Ecology of the free-living stages of cattle nematodes in the dry season in the Lerma Valley, Salta province, Argentina

The objective of this work was to describe the dynamics of development and survival of the free-living stages of cattle gastrointestinal nematodes (GIN) in fecal matter (FM) and pasture during the dry season in the Lerma Valley, Salta province, northwestern Argentina (NWA) to contribute to GIN management. The climate in the region is characterized by a rainy summer followed by a dry season from middle autumn to early spring. Fecal matter from calves naturally infected with GIN was deposited on three experimental field plots in April, July and October 2019, corresponding to the beginning, middle and end of the dry season, respectively. Each experimental unit consisted of 7 stools of about 800 g and had four repetitions. To determine the development from egg to infective larvae (L3), the first sampling (5 g fecal matter) was performed from the 10th day post-contamination and continued every 3 days until L3 were found. Subsequently, a monthly sampling was made until two consecutive negative results were obtained. Sampling of pasture began three days after the L3 recovery from FM, and continued monthly until two negative results were obtained. The following parameters were evaluated: development time and development rate from egg to L3; permanence time of L3 in feces; time of appearance on pasture; migration rate; and permanence time of L3 on pasture. The main genera of parasites present were Cooperia and Haemonchus. Significant differences were observed in the development time among contamination months (p < 0.001); development time was highest in the July contamination (28 days), with October and April contamination averaging 9 and 10 days, respectively. Development time also showed significant differences (p < 0.01) among contamination months, being highest in October (31.48%). The highest permanence time in fecal matter values were recorded in the July contamination (183 days) and migration rate was highest in the October contamination (42.49%). The highest time of appearance on pasture value was recorded in the July contamination (117 days). Finally, the highest permanence time of L3 in feces values were detected in the October contamination (148 days). The results of this work show that fecal contamination in the NWA region in the dry season would play an epidemiological role in the GIN cycle as a source of infection for the next productive cycle in the rainy season.

Neospora caninum antibodies in bulk tank milk from dairy cattle herds in Italy in relation to reproductive and productive parameters and spatial analysis

Among the available diagnostic techniques, antibody detection in bulk tank milk (BTM) represents a useful tool to estimate and monitor Neospora caninum herd prevalence. To evaluate the prevalence of N. caninum and the effect of parasite infection on herd performances, BTM samples collected from 586 dairy herds located in one of the largest dairy production areas in Italy (Lombardy) were analyzed by an indirect ELISA to detect anti-N. caninum specific antibodies. Generalized linear models (GLMs) were developed. A purely spatial analysis scanning for clusters with high or low rates for N. caninum using the Bernoulli model was performed. A maximum entropy approach was used to estimate the probability of distribution of the parasite based on occurrence records together with environmental variables. Overall, 180 herds resulted positive for N. caninum antibodies on bulk tank milk (P = 30.7 %). A higher risk of seropositivity was evidenced in the provinces of Milano, Cremona, Brescia, and Bergamo (P = 32-40 %); a lower risk was evidenced in Lodi, Pavia, and Mantova (P = 13-24 %). A higher risk of seropositivity was revealed for small-medium farms (101-300 animals) (O.R.=2.8) and for older animals with more than 4 years (O.R.=4.4). Regarding the effect of N. caninum infection on herd performances, the number of inseminations for conception was higher (> 3 inseminations), and the period from calving to conception was longer (> 150 days) for positive farms (O.R.=2.0 and O.R.=2.3, respectively); besides, lower head daily milk production (<20 kg and 21-25 kg) and mature equivalent milk yield (<11,000), and somatic cell counts higher than 300,000 cells/ml were observed for N. caninum positive herds (O.R.=0.4, O.R.=0.4 and O.R.=1.9 respectively). The geographical distribution of N. caninum positive farms with the highest level of probability covers the central sector of the Po Plain where a significant cluster for high risk of parasite infection was shown by spatial scan statistic and Maximum entropy ecological niche modelling. A further significant cluster of low risk occurred in the southern. The climatic and environmental variables with the highest training gain when used in isolation resulted altitude, land use/land cover, and other variables related to temperature and precipitation. Neosporosis is widely distributed in Italian dairy herds and an impact of the parasite on herd performances could be hypothesized. Even if the role of N. caninum in alterations of reproductive and productive parameters should be further explored, veterinarians and farmers should be aware of neosporosis, and control plans should be adopted.

Blood parameters and parasite burden in cattle with chronic fascioliasis

Fascioliasis is a trematodiasis that affects domestic and wild animals as well as humans worldwide. It is a well-recognized disease in livestock, were it produces serious economic losses. Yet in cattle, there is limited information about the burden of liver flukes and its relation to the eggs per gram shed to the environment. There is also lack of knowledge on the effect of parasite load in blood parameters of infected animals, which is important to evaluate the severity and progression of the disease. The objective of this work was to gain insight in these aspects. Cattle from Mendoza province, Argentina, were inspected at a farm and at the abattoir determining the presence or absence of Fasciola hepatica. Each animal was sampled for blood and feces and in the slaughterhouse the livers were inspected. Hematology and blood chemistry parameters were determined, feces were examined for F. hepatica eggs by a quantitative sedimentation technique and livers were thoroughly inspected to determine the number of flukes. Infected cattle presented a mild burden of liver flukes per animal, strongly correlated (r = 0.72) to the number of eggs per gram of feces. The total number of eggs (X̄=35,100) shed per animal to the environment and the type of livestock management techniques in the region exacerbate the role of cattle as efficient reservoirs of this disease. Statistically significant lower red blood cell, lymphocyte and neutrophil counts were observed in infected compared to uninfected animals. All hepatic parameters tested showed highly statistically significant differences (p < 0.001) as well as proteins by cause of rise of globulins in infected cattle. The correlation between the amount of flukes in the liver and the number of eggs per gram of faces indicates coprology as a reliable and cost-effective method to infer parasite burden. The impact of fascioliasis on blood parameters can be of aid for the veterinary practitioner on the assessment of this disease on cattle.

Resistance to natural tick infestation varies with age and coat and hair traits in a tropically adapted beef cattle breed

Rhipicephalus (Boophilus) microplus causes considerable livestock production losses. Knowledge of the traits that influence tick resistance contributes to the development of breeding strategies designed to improve herd productivity. Within this context, this study evaluated the resistance of Caracu, a tropically adapted cattle breed, to R. microplus. Tick count, hair length, coat thickness, and coat color were evaluated in 202 naturally tick-infested females (cows and heifers) over a period of 18 months. Blood samples were collected from all animals during the winter season for hematological analysis. Data were analyzed using Pearson correlations, generalized linear models, and principal component analysis. Correlation coefficients of tick count with coat color, coat thickness, and hair length were estimated within each season. Hematological parameters were only included in the winter season analysis and were analyzed by the restricted maximum likelihood method using log-transformed data. No differences in blood parameters were observed between animals with and without ticks. However, tick count was negatively correlated with erythrocytes (-0.29) and hematocrit (-0.24) and positively correlated with mean corpuscular hemoglobin (0.21) and mean corpuscular hemoglobin concentration (0.25). These findings suggest that higher tick counts lead to a decrease in erythrocytes but also to an increase in the amount of hemoglobin per erythrocyte, which could reduce the damage caused by low erythrocyte levels due to tick hematophagy, delaying or preventing anemia. Although tick infestation on pasture was demonstrated by the infestation of all staff members during herd management, none of the animals exhibited high tick counts, providing evidence of resistance of Caracu animals to R. microplus. Tick infestation was influenced by age class (cows > heifers), season (spring and summer > fall and winter), coat thickness (>1.5 mm > <1.5 mm), and hair length (>6 mm > <6 mm). Three components were extracted by principal component analysis, which accounted for 69.46% of data variance. The findings of this study will contribute to the development of efficient strategies aimed at reducing economic losses due to tick infestation and could be applied in animal breeding to select for tick resistance traits, reducing chemical control strategies and consequently improving sustainable livestock production.

Genetic characteristics of Blastocystis sp. in cattle from Hebei Province, China

Blastocystis sp. is a protozoan parasite that infects the intestines of humans and animals, causing chronic diseases such as skin rashes, abdominal pain, and irritable bowel syndrome. A survey was conducted to determine the prevalence and genetic diversity of Blastocystis sp. infection in cattle, in Hebei Province, China. 2746 cattle fecal samples were collected from 11 cities in Hebei Province and analyzed using polymerase chain reaction targeting the Blastocystis sp. barcoding gene. MEGA, PhyloSuite, and PopART were used to analyze the subtype, sequence signature, pairwise genetic distance, and genetic diversity indices. The results showed that the Blastocystis sp. detection rate was 12.60% (346/2746). The infection rate in different herds was affected by region, age, breeding mode, and variety; that is, the infection rates in areas of southern Hebei, cattle under one year old, intensive raising, and dairy cattle were higher than the infection rates in northern Hebei, cattle over one year old, scatter feeding, and beef cattle. Seven Blastocystis subtypes were identified, namely, ST1, ST2, ST5, ST10, ST14, ST21, and ST26; ST10 was the dominant subtype, and ST14 was the second most common subtype. A total of 374 polymorphic and conserved sites were obtained, including 273 invariable (monomorphic) sites and 101 variable (polymorphic) sites, accounting for 27.01% of all nucleotides. The nucleotide diversity index (Pi) was 0.07749, and the haplotype (gene) diversity index (Hd) was 0.946. This study provides the first comprehensive information on the epidemiological situation of Blastocystis sp. infection in cattle from Hebei Province, China, and revealed rich genetic diversity of Blastocystis sp.

Calicophoron daubneyi (Paramphistomidae) in deer of the Šumava National Park, Czech Republic - Consequence of prevalent rumen fluke infection in cattle

A substantial parallel increase in prevalence and geographical spread of the rumen fluke, Calicophoron daubneyi, in livestock in western and central Europe has been recognized in the recent past. In the course of the examination of rectum feces of 471 red deer (Cervus elaphus) and one sika deer (Cervus nippon) from the Fascioloides magna endemic Šumava National Park in the years 2021 and 2022, rumen fluke eggs were detected in four red deer (0.8%) and the sika deer and identified as eggs of C. daubneyi by molecular analysis. Subsequent examination of rectal fecal samples of 247 beef cattle from 22 herds of 14 farms located in or nearby the national park revealed rumen fluke eggs in 53 samples (21.5%) originating from 16 herds of 11 farms, molecularly identified as C. daubneyi eggs as well. One C. daubneyi egg positive red deer and three C. daubneyi egg positive cattle samples also contained fasciolid eggs, respectively, which were detected in 9.5% or 3.6% of the total samples from red deer or cattle, respectively. Results of this investigation reveal the first finding of C. daubneyi in sika deer worldwide and in red deer in mainland Europe and add to the growing number of reports on C. daubneyi in livestock in Europe. Considering that the ratio of cattle excreting rumen fluke eggs exceeded that of deer substantially, it can reasonably be assumed that the C. daubneyi infections in deer are a consequence of the prevalent infection in cattle, illustrating a pathogen spillover event from livestock into wildlife.

Epidemiological assessment of Anaplasma marginale, Babesia bigemina, and Babesia bovis infections in Colombian creole cattle breeds: A molecular survey in northeastern Colombia

Anaplasmosis and babesiosis are globally distributed arthropod-borne diseases known for causing substantial economic losses due to their high morbidity and mortality rates. This study aims to assess the frequency and epidemiological features associated with the infection of Anaplasma marginale, Babesia bigemina, and Babesia bovis in three Creole cattle breeds (Chino Santandereano (Chino), Casanareño (CAS), and Sanmartinero (SM)) in northeastern Colombia. Between June 2019 and March 2020, a total of 252 Creole cattle were sampled, with Chino, CAS, and SM accounting for 42.8%, 29.5%, and 29.5% of the samples, respectively. Blood samples were subjected to molecular analysis to detect the DNA of A. marginale, B. bigemina, and B. bovis, using species-specific primers. Additionally, Packed Cell Volume (PCV), total serum proteins, and body condition were evaluated. Molecular analyses revealed the presence of B. bigemina, A. marginale, and B. bovis in 83.7% (211/252; 95% CI = 79.1%-88.3%), 59.9% (151/252; 95% CI = 53.8%-66.1%), and 40.9% (103/252; 95% CI = 34.7%-46.9%) of the samples, respectively, with 69% (174/252; 95% CI = 57.8%-80.3%) exhibiting coinfections. Notably, in infected animals, no significant alterations in PCV, total serum proteins, or body condition were observed. Multivariate analyses indicated a statistically significant association between the frequency of A. marginale infection and the breed and season, with a higher frequency in SM during the rainy season (P < 0.05). To our knowledge, this is the first molecular survey that evaluates multiple arthropod-borne pathogens in Colombian Creole breeds. The results revel a high frequency of B. bigemina and A. marginale infections, coupled with a notable frequency of coinfections, all without significant alteration in the PCV, total serum proteins and body conditions. Our findings enhance the understanding of the epidemiological aspects of arthropod-borne pathogens in Colombian Creole breed and contribute to the improvement of sanitary programs for these animals.

Seroprevalence and molecular detection of Toxoplasma gondii and Neospora caninum in beef cattle and goats in Hunan province, China

BACKGROUND

Toxoplasma gondii and Neospora caninum are closely related protozoan parasites that are considered important causes of abortion in livestock, causing huge economic losses. Hunan Province ranks 12th in the production of beef and mutton in China. However, limited data are available on the seroprevalence, risk factors and molecular characterization of T. gondii and N. caninum in beef cattle and goats in Hunan province, China.

METHODS

Sera of 985 beef cattle and 1147 goats were examined for the presence of specific antibodies against T. gondii using indirect hemagglutination test (IHAT) and anti-N. caninum IgG using competitive-inhibition enzyme-linked immunoassay assay (cELISA). Statistical analysis of possible risk factors was performed using PASW Statistics. Muscle samples of 160 beef cattle and 160 goats were examined for the presence of T. gondii DNA (B1 gene) and N. caninum DNA (Nc-5 gene) by nested PCR. The B1 gene-positive samples were genotyped at 10 genetic markers using the multilocus nested PCR-RFLP (Mn-PCR-RFLP).

RESULTS

Specific IgG against T. gondii were detected in 8.3% (82/985) and 13.3% (153/1147) and against N. caninum in 2.1% (21/985) and 2.0% (23/1147) of the beef cattle and goats, respectively. Based on statistical analysis, the presence of cats, semi-intensive management mode and gender were identified as significant risk factors for T. gondii infection in beef cattle. Age was a significant risk factor for T. gondii infection in goats (P < 0.05), and age > 3 years was a significant risk factor for N. caninum infection in beef cattle (P < 0.05). PCR positivity for T. gondii was observed in three beef samples (1.9%; 3/160) and seven chevon samples (4.4%; 7/160). Genotyping of PCR positive samples identified one to be ToxoDB#10. The N. caninum DNA was observed in one beef sample (0.6%; 1/160) but was negative in all chevon samples.

CONCLUSIONS

To our knowledge, this is the first large-scale serological and molecular investigation of T. gondii and N. caninum and assessment of related risk factors in beef cattle and goats in Hunan Province, China. The findings provide baseline data for executing prevention and control of these two important parasites in beef cattle and goats in China.

In vitro efficacy testing of ivermectin against Tritrichomonas foetus trophozoites

There are no recommended drugs to treat cattle infected with the protozoan Tritrichomonas foetus (TF). Ivermectin, widely used in the treatment of intestinal parasites, was found effective against some protozoa growing in vitro. Here, its effectiveness against a TF line was investigated. Trophozoites were incubated in media with increasing concentrations of ivermectin and mortality was determined after 24 h. Ivermectin killed cells with a mean maximum effective concentration (EC50) of 2.47 μg mL-1. The effective concentration of ivermectin was rather high for a formulation suitable for systemic treatment. However, topical treatment of animals against TF could still be considered and tested.

Geographic expansion of Fasciola hepatica (Linnaeus, 1758) due to changes in land use and cover in Brazil

Fasciolosis is caused by parasites of the genus Fasciola, affecting animals and humans worldwide. In South America, the disease is a result of infection with Fasciola hepatica and although animal infections are more frequently reported, the full extent of the impact on human health due to underdiagnosis remains uncertain. This study analyzed changes in land use and the distribution of F. hepatica in bovine livers in Brazil over 18 years. Data on land use and land cover were collected from the Mapbiomas Project. Data on 414,481,963 slaughtered cattle and condemned livers due to F. hepatica infection were obtained from 4,433 municipalities. Joinpoint analysis was used to study the time series, and the Susceptible-Infected-Recovered (SIR) model was utilized to explore the behavior of F. hepatica infection. In the North, pasture areas significantly increased (P = 0.000001), while forested areas decreased (P = 0.000001). The midwestern and northern regions concentrated the highest number (>290 million) of cattle slaughtered in Brazil. More than 2 million bovine livers were infected by F. hepatica. The infected cattle originated from 194 municipalities in 2002, increasing to 747 in 2020. We consider that the changes in land use and intense cattle transportation may have caused the expansion of F. hepatica. The SIR model analyzed the spread of the disease looking at all six biomes: Caatinga, Amazon Forest, Cerrado, Pantanal, Atlantic Forest, and Pampa. Moreover, this infection not only threatens the health of animals but is also a major concern to biodiversity and vulnerable human communities in South America. Emblematic biomes such as the Amazon basin already face challenges with logging, desertification, and loss of biodiversity. Therefore, strategies for mitigating infection should include controlling illegal pasture areas, establishing health inspections of animal transport, quarantine of newly arrived animals, and livestock zoning, as well as clear One Health policies.

In-herd prevalence of Fasciola hepatica and Calicophoron / Paramphistomum spp. infections in German dairy cows with comparison of two coproscopical methods and establishment of real-time pyrosequencing for rumen fluke species differentiation

Infections with liver and rumen flukes are among the most frequent parasitic diseases in cattle worldwide. In Europe, the predominant liver fluke species is Fasciola hepatica, and the recently rapidly spreading rumen flukes are mostly Calicophoron daubneyi and occasionally Paramphistomum leydeni. In this study, 1638 faecal samples from individual dairy cows from 24 northern and 18 southern German farms as well as one central German farm, all preselected for potential F. hepatica infection, were examined to determine in-herd prevalences of liver and rumen fluke infections. Furthermore, individual faecal egg counts (FECs) were determined in the northern and central German cows. On farms with patent F. hepatica infections, the mean in-herd prevalence was 15.8% in northern Germany, 41.6% in southern Germany and 14.0% in the central German farm. Rumen fluke infections resulted in high in-herd prevalences in all regions with a mean prevalence of 46.0% in northern, 48.4% in southern and 40.0% in central Germany. Individual FECs varied between 0.1 and 4.1 (mean 0.4) eggs per gram faeces (EPG) for F. hepatica and between 0.1 and 292.4 (mean 16.9) EPG for rumen flukes. Mean in-herd prevalence and mean FECs did not differ significantly between mono- and coinfected farms for either fluke species. Comparison of the classical sedimentation technique and the Flukefinder® method on a subset of 500 faecal samples revealed a similar number of positive samples, however, Flukefinder® mean FECs were three to four times higher for liver and rumen fluke eggs, respectively, with an increasing gap between EPG levels with rising egg counts. Fluke egg size measurement confirmed P. leydeni eggs on average to be larger in length and width (161.0 µm x 87.1 µm) than those of C. daubneyi (141.8 µm x 72.9 µm). However, due to overlap of measurements, morphological species identification based on egg size proved unreliable. For accurate identification, a real-time pyrosequencing approach was established, offering the advantage over classical Sanger sequencing of unambiguously identifying rumen fluke mixed species infections. Real-time pyrosequencing confirmed C. daubneyi (78.1% [50/64]) as the predominant rumen fluke species in Germany, while P. leydeni was detected in 12.5% (8/64) of sampled cows. A total of 9.4% (6/64) cows were infected with both C. daubneyi and P. leydeni, representing the first finding of a mixed infection in domestic ruminants in Europe to date.

Assessment of oxidative stress and tissue damage in Echinococcus granulosus naturally infected bovine liver

Echinococcus granulosus is a zoonotic parasite infects many livestock species, especially cattle, sheep, goat and buffalo, causing cystic echinococcosis. The aim of this study was to demonstrate the presence of the parasite and parasitic tissue damage histopathologically and to determine the role of oxidative stress in the tissue damage through the immunohistochemical detection of the oxidative damage-marker malondialdehyde (MDA) and the antioxidant response-marker superoxide dismutase (SOD). The material of the study consisted of 20 liver samples with Echinococcus cysts and 10 E.granulosus- negative healthy liver samples obtained from different cattle at various times from slaughterhouses in Kırıkkale province, Turkey. Histopathologically, Echinococcus cysts of various sizes were observed along with the surrounding fibrous connective tissue. Giant cells, mononuclear cells, and eosinophilic leukocytes were found between the fibrous connective tissue and the cyst. In the parenchymal tissue distant from the cyst, inflammatory changes were observed, including vacuolation and necrosis in hepatocytes, congestion and dilation sinusoidal capillaries. Immunohistochemically, MDA immunopositivity was observed in both hepatocytes surrounding the cyst and areas distant from the cyst, while SOD immunopositivity was mainly detected in fibrous connective tissue and hepatocytes surrounding the Echinococcus cysts. A significant increase in MDA immunoreactivity was observed in E.granulosus s.l.-infected livers. Although no statistically significant change was observed in SOD immunopositivity in the liver tissues with cystic echinococcosis, regional variations were noted. Germinal layer (GL) of Echinococcus cyst showed immunopositive staining for MDA, while laminated layer (LL) exhibited immunonegative staining. To the authors' best understanding, this study represents a pioneering effort in showcasing and evaluating the immunoreactivities of MDA and SOD within the liver tissue afflicted with Echinococcus cysts. Simultaneously, the examination extends to encompass tissue damage and the infiltration of inflammatory cells. This study highlights the role of oxidative stress in the pathogenesis of Cystic Echinococcosis (CE) and the need for further investigation of antioxidant defense mechanisms and their regional variations.

Assesment of Hypoderma infestation in a wild population of Cervus elaphus from mountains Atlantic ecosystems in southwestern Europe (Spain)

Hypodermosis in Cervus elaphus was studied in the Riaño Regional Hunting Reserve, Province of León, north-western Spain. One hundred and ten red deer were examined for the presence of warble fly larvae. They were analyzed by PCR analysis of the COI region of mt-DNA and identified as Hypoderma actaeon. The prevalence of larvae was 42.7% with a mean intensity of 12.5 ± 18 (range 1-80) warbles/deer infested. The distribution of larvae in the infested animals showed an aggregated/overdispersed pattern (aggregation index = 25.84), where the larvae are not randomly or uniformly distributed, but strongly aggregated among their hosts. Larvae were found in all three states. First and second-instars were observed mainly in the autumn until the end of winter (November-March) and third-instars in late winter until mid-spring (March-May). The adult animals and the males had a higher prevalence than the young and the females, finding statistically significant differences only according to the sex of the animals. Seasonal variations were observed in the prevalence with the highest number of infested animals in winter and autumn, but not in terms of the mean intensity of parasites. Additionally, we assessed the presence of anti-Hypoderma antibodies in serum by means of indirect ELISA tests, using a crude larval extract (CLE) and a purified fraction the hypodermin C (HyC) obtained from first instars of Spanish isolates of Hypoderma lineatum (cattle). These findings confirm that H. actaeon is widely distributed in northern Spain, and provide new information about its chronobiology in mountainous Atlantic ecosystems from southwestern Europe.

Seasonal dynamics and genetic characterization of bovine arthropod-borne parasites in Nan Province, Thailand with molecular identification of Anaplasma platys and Trypanosoma theileri

Virulent species or strains of hematophagous borne pathogens such as Anaplasma spp., Babesia spp., Theileria spp., and Trypanosoma spp., are lethal to susceptible animals or reduce their productivity on a global scale. Nonetheless, efforts to diagnose the causative agents and assess the genotypic profiles as well as quantify the parasite burden of aforementioned parasites across seasons remain limited. Therefore, the present investigation sought to elucidate the genotypic composition of Anaplasma spp., Babesia spp., Theileria spp., and Trypanosoma spp. The findings revealed heightened infection rates during the summer, manifesting a correlation between Trypanosoma spp. infection and seasonal fluctuations. Among the identified pathogens, Anaplasma marginale emerged as the most dominant species, while the occurrence of Anaplasma platys in Thai cattle was confirmed via the sequencing of the groEL gene. Moreover, the study successfully identified two lineages of Trypanosoma theileri. The findings of this investigation offer valuable insights that can inform the development of preventive strategies for vector-borne diseases, such as considering the appropriate use of insect repellent, mosquito or insect nets, or eliminating breeding places for insects in each season.

Prevalence and risk factors of fasciolosis in a bovine population from farms in Taiping, Malaysia

Fasciolosis is a zoonotic disease, considered an emerging neglected tropical disease threatening ruminant productivity and causing economic losses. Controlling fasciolosis is challenging due to the complex life cycle of Fasciola, which involves snail intermediate hosts. The high rainfall status in Taiping makes it an optimal region for snail abundance, which increases the opportunity to complete Fasciola's life cycle. Previous studies showed that liver condemnation caused by fasciolosis was highly prevalent in the Taiping abattoir compared to other investigated main abattoirs of Peninsular Malaysia. Therefore, the present study determined the prevalence of bovine fasciolosis and risk factors in farms from Larut and Matang (Taiping), Malaysia. Sampling was carried out from February until August 2020. In this cross-sectional study, a total of 371 fecal samples from bovines (dairy cattle, beef cattle, buffalo) were examined from 23 farms selected based on location, farmer consent, and history of anthelmintic usage. Animal's intrinsic and farm management details were recorded, and interview sessions were conducted with farmers to collect information on the potential risk factors. Individual fecal samples were examined for the presence of Fasciola egg using Flukefinder® sedimentation. There was moderate prevalence of bovine fasciolosis in Taiping (36.9%, n = 137/371). Significant risk factors (p < 0.05) were observed, which include buffalo group (OR = 9.5, 95% CI: 9.44-9.55), age of >3 years (OR = 5.5, 95% CI: 5.43-5.57), thinner animals with body condition score of 1 to 4 (OR = 1.2-14.9, 95% CI: 1.09-15.08), and larger grazing area (OR = 1.3, 95% CI: 1.30-1.31). Additional risk factors include the presence of more than one ruminant species in the same farm (OR = 2.0-2.1, 95% CI: 2.00-2.22), extensive housing system (OR = 4.0, 95% CI: 3.77-4.23), farm age (OR = 1.2, 95% CI: 1.20-1.21), and also co-infection with Paramphistomes (OR = 1.4, 95% CI: 1.10-1.71). The present study underscores the importance of local bovine fasciolosis epidemiology, which could be used to conduct future veterinary and public health programmes to inform effective parasitic management aimed at reducing the prevalence of fasciolosis.

Bovine neutrophils kill the sexually-transmitted parasite Tritrichomonas foetus using trogocytosis

The protozoan parasite Tritrichomonas foetus (T. foetus) is the causative organism of bovine trichomonosis (also referred to as trichomoniasis), a sexually-transmitted infection that reduces fertility in cattle. Efforts to control trichomonosis on cattle farms are hindered by the discouragement of antibiotic use in agriculture, and the incomplete, short-lived protection conferred by the current vaccines. A more complete mechanistic understanding of what effective immunity to T. foetus entails could enable the development of more robust infection control strategies. While neutrophils, the primary responders to infection, are present in infected tissues and have been shown to kill the parasite in vitro, the mechanism they use for parasite killing has not been established. Here, we show that primary bovine neutrophils isolated from peripheral blood rapidly kill T. foetus in vitro in a dose-dependent manner, and that optimal parasite killing is reduced by inhibitors of trogocytosis. We also use imaging to show that bovine neutrophils surround T. foetus and trogocytose its membrane. These findings are consistent with killing via trogocytosis, a recently described novel neutrophil antimicrobial mechanism.

High-resolution prediction models for Rhipicephalus microplus and Amblyomma cajennense s.l. ticks affecting cattle and their spatial distribution in continental Ecuador using bioclimatic factors

In Ecuador, the main tick species affecting cattle are Rhipicephalus microplus and Amblyomma cajennense sensu lato. Understanding their spatial distribution is crucial. To assess their distribution, data from 2895 farms visited between 2012 and 2017 were utilized. Ticks were collected during animal inspections, with each farm's location georeferenced. Bioclimatic variables and vapor pressure deficit data were obtained from Climatologies at High resolution for the Earth´s Land Surface Areas (CHELSA) dataset. They were overlaid to develop predictive maps for each species using Random Forest (RF) models. The cross-validation results for RF prediction models showed high accuracy for both R. microplus and A. cajennense s.l. presence with values of accuracy = 0.97 and 0.98, sensitivity = 0.96 and 0.99, and specificity = 0.96 and 0.93, respectively. A carefully selected subset of bioclimatic variables was used to describe the presence of each tick species. Higher levels of precipitation had positive effect on the presence of R. microplus but a negative effect on A. cajennense s.l. In contrast, isothermality (BIO3) was more important for the presence of A. cajennense s.l. compared to R. microplus. As a result, R. microplus had a broader distribution across the country, while A. cajennense s.l. was mainly found in coastal areas with evident seasonality. The coexistence of both species in some regions could be attributed to transitional zones, whereas high altitudes limited tick presence. This information can aid in developing appropriate tick management plans, particularly considering A. cajennense s.l.'s broad host range species and R. microplus's specificity for cattle. Moreover, the predictive models can identify areas at risk of associated challenging hemoparasite, requiring special attention and mitigation measures.

Molecular identification, risk factor assessment, and phylogenetic analysis of tick-borne pathogens in symptomatic and asymptomatic cattle from South-Eastern Iran

Tick-borne pathogens (TBPs) represent a substantial threat to cattle globally, exerting adverse impacts on production, health, and economic viability. This study delves into the prevalence and implications of TTBPs in cattle sourced from resource-limited smallholder livestock farms situated in southeastern Iran, proximate to Afghanistan and Pakistan. Blood and tick specimens were systematically collected from a cohort of 230 cattle, comprising 150 asymptomatic and 80 symptomatic individuals. Genomic DNA isolated from blood samples underwent rigorous examination for the presence of key TBPs, including Anaplasma marginale, A. phagocytophilum, A. bovis, A. centrale, Babesia bigemina, and Theileria annulata, utilizing multiple genetic markers. Nucleotide sequence analysis facilitated the reconstruction of phylogenetic relationships. The study also evaluated various potential risk factors, such as clinical status, gender, age, breed, tick infestation, and management practices, to elucidate their associations with TTBPs. Among the cattle cohort, a staggering 87.8% (202/230) tested positive for at least one pathogen. Prevalence statistics encompassed A. marginale (72.2%), T. annulata (68.3%), A. phagocytophilum/A. platys-like complex (66.1%), A. centrale (16.7%), B. bigemina (10.0%), and A. bovis (6.1%). Remarkably, mixed infections involving two, three, and four pathogens were detected in 23%, 52.1%, and 2.2% of animals, respectively. Notably, all asymptomatic cattle were positive for at least one TBP. Tick infestation was observed in 62.2% (143/230) of cattle, predominantly caused by Hyalomma anatolicum (82.5%), Rhipicephalus (Boophilus) annulatus (13.1%), and R. sanguineus sensu lato (4.4%). Risk factors linked to TBPs encompassed tick infestation, older age, and crossbred animals. Clinical presentations among symptomatic cattle encompassed fever, anemia, weight loss, anorexia, jaundice, and enlarged superficial lymph nodes. This study underscores the pivotal role of asymptomatic carriers in the propagation of TTBPs within endemic regions. Furthermore, it emphasizes the potential for the implementation of molecular diagnostics to unmask subclinical infections, thereby affording the opportunity for targeted interventions aimed at ameliorating the burden of TTBPs in resource-constrained smallholder dairy farms.

Identification and distribution of Rhipicephalus microplus in selected high-cattle density districts in Uganda: signaling future demand for novel tick control approaches

BACKGROUND

Rhipicephalus (Boophilus) microplus (Canestrini, 1888), the Asian blue tick, is a highly invasive and adaptable ectoparasite. This tick species has successfully established itself in most regions of the world, with movement of cattle being a major driver for its spread. In the recent past, R. microplus ticks have been reported in three districts of Uganda. Information on its spread and distribution are vital in deepening our understanding of the ecological scenarios that lead to tick persistence and in the formulation of control strategies. This is especially important in the cattle-dense districts.

METHODS

We randomly collected tick specimens from 1,461cattle spread across seven cattle dense districts located in the Central, Karamoja and West Nile regions of Uganda from January to September 2020. The ticks were identified using standard morpho-taxonomic keys and the R. microplus tick species identities were confirmed by sequencing of the ITS2 region, 12S rRNA and 16S rRNA genes and phylogenetic analyses.

RESULTS

Adult ticks (n = 13,019) were collected from 1,461 cattle. Seventeen tick species were identified based on morpho-taxonomic keys and the majority (47.4%; n=6184) of these were R. appendiculatus. In total, 257 R. microplus ticks were found infesting cattle in 18 study sites in the districts of Amudat, Kaabong, Napak (Karamoja region) and Arua (West Nile region). The identity of R. microplus was confirmed using molecular technics. No R. microplus tick was recorded in the districts of Lyantonde and Nakaseke (Central region). Arua district accounted for 82.1% (n=211) of the R. microplus ticks recorded followed by Napak district at 16.3% (n=42), while Amudat and Kaabong districts accounted for 1.5% (n=4). Rhipicephalus microplus and R. decoloratus co-existed in 6 of the 13 study sites in Arua district, while in another 6 study sites, no R. decoloratus was recorded. In the Karamoja region districts R. decoloratus co-existed with R.microplus. Of the total 618 ticks belonging to four species of the subgenus Boophilus recorded in this study, R. decoloratus accounted for 50.04% (n=334), followed by R. microplus at 41.58% (n=257), R. geigyi at 2.75% (n=17) and R. annulatus at 1.61% (n=10). In the districts of Amudat, Kaabong and Napak, R. decoloratus was more dominant (76.1%; n=179) of the three Rhipicephalus (Boophilus) tick species recorded, followed by R. microplus (19.5%; n=46) and R. geigyi (4.2%; n=10). Contrariwise, R. microplus was more dominant (84%; n=211) in Arua district followed by R. decoloratus (10.7%; n=27), R. annulatus (3.9%; n=10) and R. geigyi (1.1%; n=3). Phylogenetic analyses of the ITS2 region, 12S rRNA and 16S rRNA genes revealed subgrouping of the obtained sequences with the previously published R. microplus sequences from other parts of the world.

CONCLUSION

Rhipicephalus microplus ticks were found infesting cattle in four districts of Uganda. The inability to find R. decoloratus, an indigenous tick, from six sites in the district of Arua is suggestive of its replacement by R. microplus. Rhipicephalus microplus negatively affects livestock production, and therefore, there is a need to determine its distribution and to deepen the understanding of the ecological factors that lead to its spread and persistence in an area.

Observational longitudinal study on Toxoplasma gondii infection in fattening beef cattle: serology and associated haematological findings

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is a globally distributed zoonotic infection with significant implications for human and animal health. This study investigated the prevalence of T. gondii infection in a population of beef cattle at three different stages of their productive lifespan and examined the impact of T. gondii serological status on blood parameters. A commercial beef fattening unit in Italy was the setting for this research, which involved a biosecurity assessment upon cattle arrival, blood sampling at three time points and Toxoplasma-specific serological testing using indirect fluorescent antibody tests (IFAT). Results revealed a dynamic pattern of T. gondii seropositivity in cattle, with an initial prevalence of 30.6% at arrival (T0) that increased to 44.6% at 14 days (T1) and then decreased slightly to 39.3% at slaughter after 5 months (T2). Interestingly, seroconversion was observed during the study, indicating ongoing infections, and antibody waning occurred in some animals. In terms of blood parameters, seropositive cattle exhibited significantly lower mean corpuscular volume (MCV) and a higher neutrophil-lymphocyte (N/L) ratio, suggesting an activation of the innate immune response. Furthermore, cattle with higher antibody titres displayed higher neutrophil counts. However, all blood parameters with a statistical significance were within the reference range. This study provides for the first time a longitudinal investigation on the serological status for T. gondii in naturally exposed beef cattle. These findings provide valuable insights into the clinico-pathological aspects of natural T. gondii exposure in cattle and underscore the importance of monitoring and managing T. gondii infection in livestock production systems.

The complete mitochondrial genome of cattle tick clade C reveals the genetic relationship within Rhipicephalus microplus complex

Cattle ticks (Rhipicephalus microplus) are important economic ectoparasites causing direct and indirect damage to cattle and leading to severe economic losses in cattle husbandry. It is common knowledge that R. microplus is a species complex including five clades; however, the relationships within the R. microplus complex remain unresolved. In the present study, we assembled the complete mitochondrial genome of clade C by next-generation sequencing and proved its correctness based on long PCR amplification. It was 15,004 bp in length and consisted of 13 protein genes, 22 transfer genes, and two ribosomal genes located in the two strains. There were two copies of the repeat region (pseudo-nad1 and tRNA-Glu). Data revealed that cox1, cox2, and cox3 genes were conserved within R. microplus with small genetic differences. Ka/Ks ratios suggested that 12 protein genes (excluding nad6) may be neutral selection. The genetic and phylogenetic analyses indicated that clade C was greatly close to clade B. Findings in the current study provided more data for the identification and differentiation of the R. microplus complex and made up for the lack of information about R. microplus clade C.

Nationwide survey of ticks on domesticated animals in Taiwan: Revealing the hidden threat to animal and public health

Ticks are not only bloodsucking ectoparasites but also important vectors of tick-borne diseases (TBDs), posing significant threats to public and animal health. Domesticated animals serve as critical hosts for numerous ticks, highlighting the importance of understanding tick infestations in Taiwan. To address this knowledge gap, we conducted a nationwide survey to identify ticks on domesticated animals and associated environments in 2018 and 2019. A total of 6,205 ticks were collected from 1,337 host animals, revealing the presence of seven tick species, with Rhipicephalus microplus, and Rhipicephalus sanguineus being the dominant species. High infestation rates and widespread distribution of ticks were observed on domesticated animals, especially on dogs and cattle (yellow cattle and angus cattle), and the neighbouring grassland of yellow cattle. While this study has certain limitations, it provides valuable insights into the distribution and prevalence of ticks on domesticated animals in Taiwan and their implications for controlling TBDs. Further research is needed to comprehensively understand the complex interactions among ticks, hosts and pathogens.

Systematic Review and Meta-Analysis on Piroplasma spp. Infection and Co-infection with Anaplasma marginale in Domestic Ruminants from Algeria

BACKGROUND

Piroplasmosis and anaplasmosis stand out as the primary diseases affecting livestock during periods of tick activity. These vector-borne diseases continue to emerge worldwide, exerting a detrimental impact on both animal health and national economies. The purpose of this study is to assess the prevalence of Piroplasma spp. and its co-occurrence with Anaplasma marginale in domestic ruminants in Algeria.

METHODS

Three databases were systematically reviewed to identify eligible studies for the final meta-analysis, following the PRISMA statement. The 'meta' package in the R software was employed for the meta-analysis with the random effects model chosen for data pooling.

RESULTS

The meta-analysis encompasses 14 research papers spanning a 19-year period (2004-2023). Theileria spp. was identified in all studies, covering 1675 cattle, 190 sheep, and 128 goats, yielding an overall Theileria infection rate of 45% (95% CI 26-65%). Specifically, cattle had a 59% infection rate, while sheep and goats had rates of 18% and 20%, respectively. Babesia spp. was found in nine studies, involving 1183 cattle and 190 sheep, resulting in an overall Babesia infection rate of 7% (95% CI 4-15%), with cattle and sheep having rates of 10% and 3%, respectively. Notably, eight Piroplasma species T. annulata, T. orientalis, T. buffeli, T. equi, Theileria sp., B. bovis, B. bigemina, and B. occultans were detected in cattle, with T. annulata being the most prevalent at 54%. Regional disparities and host factors also impacted infection rates, with higher rates in Northeastern Algeria and among suspected disease cattle. Additionally, gender, age, and breed influenced cattle susceptibility to Theileria infection. Furthermore, six distinct co-infections between Piroplasma spp. and A. marginale were observed, with T. annulata/A. marginale identified in six studies, demonstrating an 8.3% co-infection rate.

CONCLUSION

This analysis offers crucial insights into the current status of Piroplasmosis and its co-infection with A. marginale in Algerian domestic ruminants, providing valuable data for surveillance and prevention strategies.

Development of a "Rapid-Crypto Colorimetric LAMP Test" to Detect Cryptosporidiosis in Feces of Newborns Calves

BACKGROUND

Cryptosporidiosis is a disease that causes major intestinal damage in humans and animals. The causative agents of the disease are Cryptosporidium species. In newborn calves, diarrhea can lead to death, resulting in significant economic losses for the farms. Therefore, accurate, rapid, and cost-effective diagnosis of the disease is very important.

MATERIAL AND METHODS

In this study, a novel colorimetric loop-mediated isothermal amplification (LAMP) test named "Rapid-Crypto Colorimetric LAMP test" targeting Cryptosporidium spp. 18S rRNA gene was developed to detect cryptosporidiosis in the feces of newborn calves. The analytical sensitivity of the test was determined by plasmid controls. Clinical sensitivity was determined using the feces of 127 calves collected from farms in İzmir and Manisa provinces. All of the samples were also investigated with Real-Time PCR targeting the Cryptosporidium spp. COWP gene. Cross-reactivity was tested using the DNA of other parasites and bacteria.

RESULTS

According to the results, the analytical sensitivity of the "Rapid-Crypto Colorimetric LAMP test" was found as 1 copy plasmid/reaction. When the results were compared with the Real-Time PCR test, the sensitivity of the "Rapid-Crypto Colorimetric LAMP test" was 100% and the specificity was 97.4%. The test did not cross-react with other parasites and bacteria.   CONCLUSION: The "Rapid-Crypto Colorimetric LAMP test" developed in this study provides an advantage in the diagnosis of Cryptosporidium spp. in calf stool samples since it can be applied in basic laboratories or in the field, does not require experienced personnel, and has high sensitivity. Moreover, diagnosis can be made with the naked eye without using any device.

Sympatric occurrence of Taenia saginata and Sarcocystis spp. in cattle from Narok County, Kenya: meat inspection findings with molecular validation

The epidemiological picture of Taenia saginata infections in Kenya is fragmented with limited available data. Although Sarcocystis species are significant meat-borne parasites, few studies have explored their occurrence in Kenya. This study aimed to estimate the occurrence of bovine cysticercosis and screen for the presence of Sarcocystis spp. A meat inspection-based survey was conducted in ten abattoirs in Narok County, Kenya, and inspection for T. saginata cysticerci was limited to the Triceps brachii muscle. The apparent occurrence of the parasite was 5.4% (95% CI, 3.8, 7.6, n=573). Molecular confirmation of T. saginata was done via nested polymerase chain reaction targeting the mitochondrial 12S ribosomal RNA gene and restricted fragment length polymorphism. Sarcocystis species were identified using a multiplex polymerase chain reaction method targeting the 18S ribosomal RNA gene sequences and the mitochondrial cytochrome c oxidase subunit I gene. Of the 31 cystic lesions tested, 26/31 (83.9%) were confirmed to be T. saginata.Sarcocystis cruzi and S. hominis were detected in 8/31 (25.8%) and 1/31 (3.2%) of the cystic lesions, respectively. Co-infections of S. cruzi and T. saginata were found in 6/31 lesions (19.4%). The confirmation of bovine cysticercosis and S. hominis is suggestive of the presence of risky culinary and sanitation practices that facilitate transmission. This is the first report and molecular confirmation of Sarcocystis spp. in cattle in the country. The presence of both zoonotic S. hominis and pathogenic S. cruzi highlights an underexplored concern of veterinary and human health significance, warranting further epidemiological investigation.

Expression of sex-specific molecular markers by Babesia bovis gametes

BACKGROUND

Bovine babesiosis caused by Babesia bovis is one of the most important tick-borne diseases of cattle in tropical and subtropical regions. Babesia bovis parasites have a complex lifecycle, including development within the mammalian host and tick vector. In the tick midgut, extracellular Babesia parasites transform into gametes that fuse to form zygotes. To date, little is known about genes and proteins expressed by male gametes.

METHODS AND RESULTS

We developed a method to separate male gametes from in vitro induced B. bovis culture. Separation enabled the validation of sex-specific markers. Collected male gametocytes were observed by Giemsa-stained smear and live-cell fluorescence microscopy. Babesia male gametes were used to confirm sex-specific markers by quantitative real-time PCR. Some genes were found to be male gamete specific genes including pka, hap2, α-tubulin II and znfp2. However, α-tubulin I and ABC transporter, trap2-4 and ccp1-3 genes were found to be upregulated in culture depleted of male gametes (female-enriched). Live immunofluorescence analysis using polyclonal antibodies confirmed surface expression of HAP2 by male and TRAP2-4 by female gametes. These results revealed strong markers to distinguish between B. bovis male and female gametes.

CONCLUSIONS

Herein, we describe the identification of sex-specific molecular markers essential for B. bovis sexual reproduction. These tools will enhance our understanding of the biology of sexual stages and, consequently, the development of additional strategies to control bovine babesiosis.

Coproprevalence, seroprevalence, and geographic distribution of Fasciola spp. infection in beef and dairy cattle in Pak Chong highland, Nakhon-Ratchasima Province, Northeast Thailand

Fasciola spp. is a major livestock parasite, especially in cattle, water buffalo, sheep, and goats. Infection reduces animal productivity, e.g., meat, dairy, wool and might cause death. In Thailand, reports of Fasciola spp. infection in livestock, especially dairy and beef cattle, are sparse. Pakchong district in Nakhon Ratchasima province is one of Thailand's largest farming areas for dairy and beef cattle, but the prevalence of Fasciola spp. infection has never been reported in this district. The landscape of this area is mainly a hilltop plateau with many water sources suitable for the development of lymnaeid snails, the intermediate host of Fasciola spp., which are essential for the parasite life cycle. This study surveyed the copro- and seroprevalence of Fasciola spp. infection in dairy and beef cattle farmed in Pakchong district by microscope-based examination, PCR, and indirect ELISA. Associated risk factors and geographic information data were collected and analyzed. Paired stool and serum samples were collected from 102 dairy cattle and 99 beef cattle from April to November 2021. Sample analyses demonstrated a high prevalence of Fasciola spp. infection, especially in beef cattle. The overall copro-prevalence was 5.97%, with 0.99% in dairy cattle and 11.11% in beef cattle. The overall seroprevalence was 23.88%, with 2.94% in dairy cattle and 45.45% in beef cattle. Moreover, the data indicated that infection status was not correlated with animal sex and age whereas consumption of natural grasses, water resources, housing floor, and farming system were significant risk factors. Data analysis by a geographic information system (GIS) demonstrated that an associated risk could be farmed in lowering areas, especially in Chan Thuck, Nong Sa Rai, and Khlong Muang subdistricts. In conclusion, this study reports the prevalence of Fasciola spp. infection in cattle in a major farming area of Thailand which could be beneficial for designing parasite control policies in this region as well as adapting this knowledge to other Fasciola spp. endemic areas.

Stochastic modelling to predict a priori the potential outcomes of different control schemes against the cattle tick Rhipicephalus microplus

Stochastic models are valuable tools to describe and analyze tick population dynamic in a given area, and to evaluate different control schemes. The objective of this study was to provide a tool to predict a priori how a control scheme could affect the abundance of Rhipicephalus microplus in an area highly favourable for its development, through the building of a stochastic model of the population dynamic of this tick. The dynamic was stochastically modelled using field data of the parasitic and non-parasitic phases of R. microplus. The host susceptibility to tick infestations was also considered by including representative values of natural resistance of three different breeds (Bos indicus, B. taurus and B. indicus x B. taurus). Two different control schemes (strategic and threshold methods) using three annual applications of synthetic acaricides in different moments were evaluated. Furthermore, we have evaluated the impact of different moments of pasture spelling as a tool for tick control on the dynamic of the non-parasitic phases of R. microplus. The results showed that the model appropriately fits to field data and can simulate the annual variability in female ticks count in animals from different ecological characteristics. The model has also captured the variability that host susceptibility has on tick abundance. This fact was expressed in the different levels of tick abundance obtained for the three breeds of bovines. According to the model, strategic control applications of chemical acaricides have more efficacy than the threshold control method. The model indicates that a pasture spelling started in early or mid-summer generates a higher reduction in the number of available eggs in pastures. Analysis of the results allows to conclude that the model developed in this study was useful to predict a priori the performance of different control methods based on the strategic application of chemical acaricides or by applying pasture spelling.

Bayesian hierarchical modelling of the geospatial distribution of fasciolosis in dairy cattle and the impact on production: Application to the main milk-producing region (Galicia) in Spain

Fasciolosis caused by Fasciola hepatica is a common parasitic infection among cattle in many countries. Although infected adult cows rarely show overt clinical signs, milk production may be impaired. Thus, significant production losses may occur in dairy herds with a high prevalence of fasciolosis. In this study, Bayesian hierarchical modelling was used to estimate the geospatial distribution of dairy cattle fasciolosis and its impact on milk production. The study was conducted in Galicia, the main milk producing region in Spain and a geographically heterogeneous area. The aims were: 1) to model the geospatial distribution of fasciolosis in dairy herds in the study area, 2) to identify clusters of herds with a high prevalence of fasciolosis, and 3) to assess the effect of fasciolosis on milk yield and quality. A large number of dairy cattle farms (n = 4907), of which 1660 provided production records, were surveyed. Fasciola infection status was determined by applying the MM3-SERO ELISA test to bulk tank milk samples. A high probability of infection was predicted in several zones, particularly in the centre, northeast and southeast of Galicia. Conversely, the predicted probability was very low in some parts of the northwest of the region. Infections with high within-herd prevalence (> 25% lactating cows infected) predominated. High within-herd prevalence was associated with loss of milk production (-1.387 kg/cow/ day, on average). No association between Fasciola infection and either milk fat or protein content was observed. This study has generated the first maps of the spatial distribution of the probability of Fasciola infection in dairy cattle herds in Galicia. The maps presented here can be used for reference purposes, enabling the design of better targeted fasciolosis control programmes in the region. Use of Bayesian hierarchical statistical analysis enabled us to ascertain the uncertainty of the predictions and to account for the spatial autocorrelation in the data. It also enabled us to generate maps showing the residual spatial variation in milk production, a topic that may deserve more detailed study.

Activation of murine macrophages by membrane proteins from Tritrichomonas foetus grown on iron- and calcium-rich conditions

Tritrichomonas foetus is a protozoan parasite that causes a venereal disease in cattle limiting reproduction by abortions and sterility. The immune response against this parasite is poorly understood. Since the iron and calcium ions are important regulators of the microenvironment of the urogenital tract in cattle, we decided to evaluate the role of these divalent cations on the antigenicity of membrane proteins of T. foetus on macrophage activation as one of the first inflammatory responses towards this pathogen. Colorimetric methods and ELISA were used to detect the nitric oxide and oxygen peroxide production and expression of cytokines in culture supernatant from macrophage incubated with membrane proteins from T. foetus cultured in iron- and calcium-rich conditions. qRT-PCR assays were used to evaluate the transcript expression of genes involved in the inflammatory response on the macrophages. The membrane proteins used for in vitro stimulation caused the up-regulation of the iNOS and NOX-2 genes as well as the generation of NO and H2 O2 in murine macrophages on a dependent way of the metal concentrations. Additionally, after stimulation, macrophages showed a considerable rise in pro-inflammatory cytokines and a downregulation of anti-inflammatory cytokines, as well as up-regulation in the transcription of the TLR4 and MyD88 genes. These data suggest that membrane proteins of T. foetus induced by iron and calcium can activate an inflammatory specific macrophage response via TLR4/MyD88 signalling pathway.

Simultaneous resistance to multiple anthelmintic classes in nematode parasites of cattle in New Zealand

Resistance to the benzimidazole and macrocyclic lactone anthelmintics is widespread in Cooperia spp. on cattle farms in New Zealand. Since this was first documented in 2006 little has changed in cattle farming systems except for the widespread use of levamisole to control Cooperia spp. in young cattle (i.e., parasite control has maintained an almost total reliance on use of anthelmintics). Here we report the emergence of simultaneous resistance to the benzimidazole, macrocyclic lactone and levamisole anthelmintics in Cooperia spp. and in Ostertagia spp. Anthelmintic efficacy against nematode parasites of cattle was investigated on four commercial farms following reports of poor animal growth rates and welfare, and positive faecal egg counts, despite routine treatment with combination anthelmintics, which included levamisole. Faecal egg count reduction tests involved 15 animals per treatment group, individual egg counts (paired samples) conducted pre- and post-treatment, with eggs counted to ≤ 15 eggs per g faeces and larval cultures for morphological identification. Actives tested varied between farms but always included levamisole alone and several combination products containing levamisole. Of the 20 tests conducted (i.e., 5 products on each of 4 farms) only 3 exceeded 90% efficacy against Cooperia spp. even though 8 of the products tested were combinations containing levamisole and at least one other broad-spectrum anthelmintic. Levamisole used alone achieved efficacies between 44% and 71% against Cooperia spp. across the four trials. The only product to exceed 95% efficacy against Cooperia spp. was a combination of monepantel + abamectin which was 100% effective against all parasites. Resistance to oxfendazole in Ostertagia spp. was indicated on 3 farms, while on one farm efficacy of all the tested products was ≤75% against this parasite. All the farms involved in this study were farming intensive cattle operations with an almost total reliance on anthelmintics to control parasitism. The results clearly demonstrate the emergence of simultaneous resistance to oxfendazole, levamisole and the macrocyclic lactone anthelmintics. Despite years of advice and recommendations to change farming practices away from intensive monocultures, many farmers have continued with the practice, and some are now faced with the very real possibility of being unable to control cattle parasites on their farms.

Gastrointestinal parasitosis in cattle: Unveiling the landscape across diverse production systems in Bangladesh

BACKGROUND

Factors influencing parasitosis in cattle in Bangladesh remain inadequately explored, necessitating a comprehensive investigation for interventions and sustainable livestock farming.

OBJECTIVES

We conducted this study to estimate the prevalence and distribution of gastrointestinal parasites, exploring their intricate relationship with farm management practices across a spectrum of small-, medium-, and large-scale commercial farms.

METHODS

We conducted this study in the Chattogram district of Bangladesh. We collected a total of 189 freshly voided faecal samples from different farms. We recorded the age, breed, milking status, sex, body condition score, and anthelmintic use history of the sampled animals. We processed the samples using the direct smear method, with the identification of one egg per sample being considered positive.

RESULTS

We estimated the prevalence of gastrointestinal parasite infection in large-scale (52.1%), medium-scale (54.5%), and small-scale farms (70.0%), with statistically significant differences (p ≤ 0.05). Both pregnant and lactating cows, as well as indigenous cattle, were more likely to have gastrointestinal parasites (p ≤ 0.05). The predominant parasites across farms of all sizes were trematodes (Paramphistomum spp. and Schistosomas spp.) and protozoa (Balantidium coli and Coccidia spp.).

CONCLUSION

Poor farm management practices, such as no pasture management and inadequate deworming regimens, may contribute to the elevated prevalence and infection load observed on small-scale farms. The increased parasitosis in previously dewormed animals can be attributed to the development of anthelmintic resistance against gastrointestinal parasites. Implementing proper and effective deworming strategies is crucial to preventing gastrointestinal parasitosis and mitigating the risk of anthelmintic resistance.

Random forest classification as a tool in epidemiological modelling: Identification of farm-specific characteristics relevant for the occurrence of Fasciola hepatica on German dairy farms

Fasciola hepatica is an internal parasite of both human and veterinary relevance. In order to control fasciolosis, a multitude of attempts to predict the risk of infection such as risk maps or forecasting models have been developed. These attempts mainly focused on the influence of geo-climatic and meteorological features. Predicting bovine fasciolosis on farm level taking into account farm-specific settings yet remains challenging. In the present study, a new methodology for this purpose, a data-driven machine learning approach using a random forest classification algorithm was applied to a cross-sectional data set of farm characteristics, management regimes, and farmer aspects within two structurally different dairying regions in Germany in order to identify factors relevant for the occurrence of F. hepatica that could predict farm-level bulk tank milk positivity. The resulting models identified farm-specific key aspects in regard to the presence of F. hepatica. In study region North, farm-level production parameters (farm-level milk yield, farm-level milk fat, farm-level milk protein), leg hygiene, body condition (prevalence of overconditioned and underconditioned cows, respectively) and pasture access were identified as features relevant in regard to farm-level F. hepatica positivity. In study region South, pasture access together with farm-level lameness prevalence, farm-level prevalence of hock lesions, herd size, parity, and farm-level milk fat appeared to be important covariates. The stratification of the analysis by study region allows for the extrapolation of the results to similar settings of dairy husbandry. The local, region-specific modelling of F. hepatica presence in this work contributes to the understanding of on-farm aspects of F. hepatica appearance. The applied technique represents a novel approach in this context to model epidemiological data on fasciolosis which allows for the identification of farms at risk and together with additional findings in regard to the epidemiology of fasciolosis, can facilitate risk assessment and deepen our understanding of on-farm drivers of the occurrence of F. hepatica.

Transcriptome profiling of Madin-Darby bovine kidney cells uncover differences in the susceptibility of cattle to Toxoplasma gondii and Neospora caninum

Toxoplasma gondii and Neospora caninum are two major apicomplexan protozoan parasites with heteroxenous life cycles and worldwide distributions. The transplacental transmission of N. caninum causes bovine abortion, which resulting in serious economic losses to the dairy industry. Although T. gondii was also reported to cause abortions in pregnant woman and small ruminants, scarce cases about the symptom to the host cattle and the causality remains unknown. In this study, transcriptome analysis of Madin Darby bovine kidney (MDBK) cells infected with T. gondii and N. caninum was performed to uncover the differences in susceptibility of cattle to the two parasites. The results showed that 256 and 2225 differentially expressed genes (DEGs) were detected in cells infected with N. caninum and T. gondii, respectively. Moreover, significant biological differences were revealed by the functional analysis including GO and KEGG enrichment. One serpin peptidase inhibitor (SEPRINA14), which is associated with immunosuppression during pregnancy, was found to significantly decrease in cells infected with N. caninum and increase in cells infected with T. gondii-infected cells. Pattern recognition receptors TLR3 and NOD2 were also significantly upregulated in N. caninum-infected MDBK cells, but not in T. gondii. They could induce an increased inflammatory response leading to severe tissue damage. In addition, the interleukin 12 receptor subunit beta 2 (IL12β2), which plays an essential role in Th1 and Th2 cell differentiation and inflammatory bowel disease, was also markedly upregulated in the N. caninum infected cells, which led to an imbalance in the Th1 and Th2 cells by promoting the Th1 cellular response. Altogether, our findings recognized a new understanding on the differences between T. gondii and N. caninum infection of MDBK cells, where SEPRINA14, TLR3, NOD2, and IL12β2 may be the key genes that affect the difference in susceptibility of cattle to T. gondii and N. caninum, especially in pregnant animals. This study provides more clues as to why N. caninum is more likely to cause abortions in cattle.

Anti-parasitic benzoxaboroles are ineffective against Theileria parva in vitro

East Coast Fever (ECF) is a disease affecting cattle in sub-Saharan Africa, caused by the tick-borne Apicomplexan pathogen Theileria parva. The disease is a major problem for cattle farmers in affected regions and there are few methods of control, including a complex infection and treatment vaccine, expensive chemotherapy, and the more widespread tick control through acaricides. New intervention strategies are, therefore, sorely needed. Benzoxaboroles are a versatile class of boron-heterocyclic compounds with demonstrable pharmacological activity against a diverse group of pathogens, including those related to T. parva. In this study, the in vitro efficacy of three benzoxaboroles against the intracellular schizont stage of T. parva was investigated using a flow cytometry approach. Of the benzoxaboroles tested, only one showed any potency, albeit only at high concentrations, even though there is high protein sequence similarity in the CPSF3 protein target compared to other protozoan pathogen species. This finding suggests that benzoxaboroles currently of interest for the treatment of African animal trypanosomiasis, toxoplasmosis, cryptosporidiosis and malaria may not be suitable for the treatment of ECF. We conclude that testing of further benzoxaborole compounds is needed to fully determine whether any lead compounds can be identified to target T. parva.

First record of Babesia and Theileria parasites in ticks from Kassena-Nankana, Ghana

Ticks are efficient vectors for transmitting pathogens that negatively affect livestock production and pose a risk to public health. In this study, Babesia and Theileria species were identified in ticks collected from cattle, sheep and goats from the Kassena-Nankana Districts of Ghana between February and December 2020. A total of 1550 ticks were collected, morphologically identified, pooled and screened for pathogens using primers that amplify a 560 bp fragment of the ssrRNA gene and Sanger sequencing. Amblyomma variegatum (62.98%) was the predominant tick species. From the 491 tick pools screened, 12/15 (2.44%) positive pools were successfully sequenced. The pathogen DNA identified were Theileria ovis in eight (15.38%) pools of Rhipicephalus evertsi evertsi, Theileria velifera in two (0.78%) pools of A. variegatum and Babesia occultans and Babesia sp. Xinjiang in one (1.72%) pool each of Hyalomma truncatum. It was further observed that T. ovis occurred in ticks collected from only sheep (p < 0.001) which were females (p = 0.023) and < =1 year old (p = 0.040). This study reports the first identification of these pathogens in ticks within Kassena-Nankana. With the constant trade of livestock, there is a need for effective tick control measures to prevent infection spread.

An epidemiological survey of vector-borne pathogens infecting cattle in Kyrgyzstan

Cattle production is a major contributor to the national economy of Kyrgyzstan. Most cattle in Kyrgyzstan are managed via extensive systems and graze in communal pastures. As a result, infestations with ectoparasites are widespread, implying that various vector-borne diseases might be common in cattle. However, methods to control such infectious diseases are not available in Kyrgyzstan because the epidemiology of vector-borne pathogens (VBPs) infecting cattle remains unclear. The present study was therefore designed to survey Kyrgyz cattle for VBPs. We prepared blood DNA samples from 319 cattle in Kyrgyzstan and screened them with specific PCR assays for detecting Babesia bovis, Babesia bigemina, Babesia naoakii, Theileria annulata, Theileria orientalis, Trypanosoma evansi, Trypanosoma theileri, and Anaplasma marginale infections. Our findings indicated that the surveyed cattle were infected with six of the eight pathogens targeted, with the exceptions being B. naoakii and Try. evansi. The most common pathogen was T. orientalis (84.3%), followed by B. bigemina (47.6%), T. annulata (16.6%), A. marginale (11.6%), Try. theileri (7.2%), and B. bovis (2.5%). Additional screening of the B. bovis- and B. bigemina-negative samples with a Babesia genus-specific 18S rRNA PCR identified two positive samples, and sequencing analysis confirmed that each of them was infected with either Babesia major or Babesia occultans. To the best of our knowledge, this is the first report of B. bovis, B. bigemina, B. occultans, Try. theileri, and A. marginale infections in cattle in Kyrgyzstan. Our findings suggest that cattle in Kyrgyzstan are at high risk of infectious diseases caused by VBPs.

Cryptosporidium infections in asymptomatic calves up to 4 months in Poland: a cross-sectional population study

Cattle cryptosporidiosis is noted worldwide with varied frequency of infection prevalence depending on geographical, environmental and husbandry factors. In this study, the prevalence of Cryptosporidium infections in cattle was determined on the basis of molecular results obtained by testing 1601 faecal samples collected from calves up to 4 months of age housed in all Polish provinces from 2014 to 2018. Detection and identification of Cryptosporidium species was performed at the 18 small subunit ribosomal RNA (18S rRNA) locus by conducting PCR-RFLP analysis of the amplified DNA fragments. The prevalence of Cryptosporidium infections in the cattle population was 45.3% (CI 95%: 42.8-47.7; 725/1601). The infected animals were housed on 233/267 (87.3%) of monitored farms with regional prevalence ranging from 27.8 to 62%. The restriction pattern of 18S rRNA amplicons for positive samples was characteristic of C. parvum, C. bovis, C. ryanae, C. andersoni, and unexpectedly also of C. baileyi and C. suis. Infections of C. bovis and C. ryanae prevailed in the studied cattle population relegating C. parvum to third in prevalence. Likewise, mixed infections caused by C. bovis and C. ryanae as well as C. parvum and C. bovis were observed. A relationship between the infecting parasite species and animal breed was found. For instance, C. parvum prevailed in Black and White lowland breed, C. ryanae in Limousine cattle and C. andersoni in dairy animals of mixed dairy breeds. Furthermore, differences in prevalence of particular parasite species between cattle breeds were also shown.

Diversity of Thelazia spp. in domestic cattle from Romania: epidemiology and molecular diagnosis by a novel multiplex PCR

BACKGROUND

Thelaziosis is a neglected vector-borne disease caused by parasitic nematode worms of the genus Thelazia which affects various hosts. Limited attention has been given to ungulate-associated Thelazia species. Current diagnosis of thelaziosis and the identification/differentiation of species heavily relies on morphological features. Therefore, we conducted an epidemiological study in Romanian cattle, with the aim to obtain morphological and molecular data that can be used for species identification.

METHODS

The eyes of 705 slaughtered cattle were sampled and subjected to morphological identification, morphometric analysis, and molecular characterization. PCR amplification and sequence analysis were performed based on the cytochromec oxidase subunit 1 (COI) gene. Statistical tests assessed the correlations between infection parameters and ecological or biogeographical factors. A novel PCR method was developed based on the consensus sequence from each species. Specific forward primers were designed for each of the three species, and a reverse primer (COIintR) was used for all reactions. A consensus thermal profile was established by gradient PCR amplification of each species separately.

RESULTS

Of the sampled cattle, 19.3% were infected with Thelazia spp. Prevalence varied significantly with ecogeographical factors. A total of 585 Thelazia nematodes were recovered, with T. rhodesi being the most abundant, followed by T. skrjabini and T. gulosa. Morphometric and molecular analyses supported the morphological identification, yielding unique sequences for each species. From the 59 T. rhodesi specimens sequenced, 29 unique sequences were obtained, with a 99.1-99.85% nucleotide identity to the only other COI sequence present in GenBank®. All nine T. gulosa isolates were unique (99.37-100% nucleotide identity to other sequences), while T. skrjabini specimens displayed 98.47-100% nucleotide identity to the sole available sequence.

CONCLUSIONS

Bovine thelaziosis is prevalent in Romania, raising concerns for animal welfare and potential economic impacts. Infected cattle grazing alongside vulnerable wild ruminants, such as the European bison, may affect conservation efforts. Our newly developed multiplex PCR shows promise as a valuable surveillance tool, enabling the detection of occult infections in apparently healthy animals through lachrymal secretion testing.

Efficacy in US cattle of a novel fixed-dose combination injectable (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) against naturally acquired gastrointestinal nematode infections

Reports of macrocyclic lactone (ML) loss of efficacy suggest ML resistance in gastrointestinal nematodes (GINs) is a growing problem in the US cattle industry. Empirical and modeling data support combining an ML and second anthelmintic from a different drug class to help ML resistance development while effectively treating existing resistant parasite populations. Here, we present a novel fixed-dose combination injectable (FDCI) solution for cattle that delivers 0.2 mg of doramectin and 6.0 mg of levamisole hydrochloride (HCl) per kg of body weight. Field studies were conducted at six sites across the Midwest United States to investigate the efficacy of a single administration of the FDCI in treating common cattle GINs. Cattle (n = 425) with GIN infections confirmed by fecal egg count (FEC) on Day -10( ± 2) were randomly allocated to the control (saline) or treatment (FDCI) group. On Day 0, pre-treatment fecal samples were collected, and cattle were administered a single subcutaneous injection of saline (n = 106) or FDCI (n = 319). Post-treatment fecal samples were collected on Day 14. Fecal egg count reduction tests (FECRTs) were conducted using Day 0 and Day 14 FECs. Efficacy was evaluated using Day 14 FECs (FDCI-treated versus saline-treated). Within treatment, samples collected on Days 0 and 14 with ≥ 20 eggs per gram (EPG) were cultured for nematode larvae recovery and identification. Day -10 FECs for enrolled animals were similar between treatment groups. Coprocultures from cattle with FEC ≥ 20 EPG (n = 68 saline; n = 211, FDCI) on Day 0 showed the presence of Cooperia punctata, Ostertagia spp., Haemonchus spp., C. oncophora, Oesophagostomum spp. and Trichostrongylus spp. Day 14 FECs for FDCI-treated cattle were significantly reduced (0-3 EPG) compared to saline-treated cattle (0-1252 EPG) (p ≤ 0.0042). At all study sites, the efficacy of the new FDCI was ≥ 99.4% and the FECR was 0.99 or 1.00. Day 14 coprocultures from control cattle showed infections of common GIN genera, confirming the efficacy of the FDCI against GINs in the field. A single administration of the doramectin + levamisole HCl combination injectable effectively treats common and economically important cattle GINs.

Efficacy of a fixed-dose combination injectable (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) in New Zealand cattle against naturally acquired gastrointestinal nematode populations with demonstrated resistance to doramectin

Intensive farming practices and heavy reliance on anthelmintics have contributed significantly to the problem of macrocyclic lactone (ML) resistance in New Zealand. Farmers now have few options for effectively controlling cattle gastrointestinal nematodes (GINs) and regularly experience sub-optimal efficacy against economically important species. We present a novel fixed-dose combination injectable (FDCI) that simultaneously delivers 0.2 mg/kg doramectin and 6 mg/kg levamisole hydrochloride (HCl) to target a broad spectrum of cattle GINs in a single dose, providing an additional solution to endoparasite control in an environment of anthelmintic resistance. A dose confirmation study was conducted using naturally acquired infections of GINs in beef cattle in New Zealand. Cattle with GIN infections confirmed by fecal egg count (FEC) were randomly allocated (n = 12 per group) to the control (saline-treated), FDCI-treated or doramectin-treated group. On Day 0, cattle were weighed and administered a single subcutaneous injection of saline or endectocide. Rectal fecal samples were collected from each animal on Day 7 for individual duplicate fecal egg count (FEC) analysis, and coprocultures were conducted on pooled fecal samples within each treatment group. All animals were euthanized and necropsied for worm recovery on Days 14 through 16. Treatment efficacy was calculated based on reduction in FECs and worm burdens. All enrolled cattle were positive for GINs based on Day -5 FECs, with geometric mean (GM) FECs ranging from 337 to 521 eggs per gram (EPG). All saline-treated cattle remained positive for GIN infections for the study duration (Day 7 GM FEC = 427 EPG). Necropsy and worm recoveries revealed the presence of doramectin-resistant Cooperia oncophora, C. surnabada and Trichostrongylus longispicularis, as evidenced by ≤ 72.3 % efficacy of doramectin against these species. The new FDCI was ≥ 99.8 % effective against all GIN species, including ML-resistant C. oncophora, C. surnabada and T. longispicularis, providing broad-spectrum efficacy and eliminating economically important cattle GINs, including ML-resistant populations.

Comparative growth performance of backgrounded beef heifers treated with an injectable fixed-dose combination (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) or single-active (0.2 mg/kg ivermectin) endectocide

Gastrointestinal nematodes (GINs) can negatively impact all production classes of cattle, particularly growing cattle. A global decline in efficacy of broad-spectrum single-active anthelmintics requires alternative GIN control methods without the aid of novel drug classes. Here, we present a new fixed-dose combination injectable (FDCI) endectocide for cattle that combines doramectin (5 mg/ml) and levamisole hydrochloride (150 mg/ml). A 56-day comparative performance confinement backgrounding trial was conducted in stocker beef heifers (n = 1548) with confirmed GIN infections to (1) compare the Day 14 post-treatment effectiveness of the new FDCI endectocide to pen mates treated with the injectable single-active endectocide ivermectin, as evidenced by fecal egg counts (FECs) conducted for a randomly selected subset (10%) of both treatment groups, and (2) determine if the greater GIN control by the FDCI evidenced in the subsample improved growth performance in all FDCI-treated heifers. Heifers were procured in four cohorts, with a 10-week timeframe between enrollment of the first and last cohort. Treatment groups were comingled within dirt-floor pens (n = 31; 7-8 per cohort) and offered a standard backgrounding diet ad libitum for the study duration. Heifers with enrollment FEC ≥ 30 eggs per gram (EPG) were randomly allocated to receive the FDCI (n = 773) or ivermectin (n = 775) on Day 0. Day 0 FECs conducted on 10% of enrolled heifers (FDCI, n = 78; ivermectin, n = 79) were not different between treatment groups (p = 0.491). Day 14 FECs for the same heifers were reduced compared to Day 0 within each treatment group. Heifers given the FDCI had lower Day 14 AM FECs and higher FEC reduction test (FECRT) result (0.07 EPG; 0.999) than ivermectin-treated heifers (21.58 EPG; FECRT = 0.850). Mean body weight (BW) was not different between treatment groups on Day 0 (p = 0.2762) and Day 14 (p = 0.2010) but was significantly greater (p = 0.0007) for FDCI-treated heifers compared to ivermectin-treated heifers on Day 56. Compared to ivermectin-treated heifers, overall average daily gain from all evaluation periods (Day 0-14, Day 14-56, and Day 0-56) was greater (p ≤ 0.0052) in FDCI-treated heifers, and FDCI-treated heifers had 4.223 kg greater total weight gain over the 56-day study. The FDCI (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) was highly effective in reducing GIN infections and thus promoted improved growth performance in beef heifers over a 56-day backgrounding period.

Analysis of the bacterial community in female Rhipicephalus microplus ticks from selected provinces in Luzon, Philippines, using next-generation sequencing

Analysis of the tick microbiome can help understand tick-symbiont interactions and identify undiscovered pathogens, which may aid in implementing control of ticks and tick-borne diseases. The tropical cattle tick Rhipicephalus microplus is a widespread ectoparasite of cattle in the Philippines, negatively affecting animal productivity and health. This study characterized the bacterial community of R. microplus from Luzon, Philippines, through next-generation sequencing of 16s rRNA. DNA was extracted from 45 partially engorged female ticks from nine provinces. The DNA samples were pooled per province and then sequenced and analyzed using an open-source bioinformatics platform. In total, 667 operational taxonomic units (OTUs) were identified. The ticks in all nine provinces were found to have Coxiella, Corynebacterium, Staphylococcus, and Acinetobacter. Basic local alignment search tool (BLAST) analysis revealed the presence of known pathogens of cattle, such as Bartonella, Ehrlichia minasensis, and Dermatophilus congolensis. The tick samples from Laguna, Quezon, and Batangas had the most diverse bacterial species, whereas the tick samples from Ilocos Norte had the lowest diversity. Similarities in the composition of the bacterial community in ticks from provinces near each other were also observed. This is the first study on metagenomic analysis of cattle ticks in the Philippines, providing new insights that may be useful for controlling ticks and tick-borne diseases.

Bovine cysticercosis epidemiology and the economic impact of the triceps brachii incision in a South African export abattoir

Taenia saginata is a zoonotic tapeworm of humans with bovines as its intermediate host (bovine cysticercosis). Traditional meat inspection is the main measure to identify the larval stage in carcasses and prevent human infection, but has a notoriously low sensitivity, especially in low prevalence settings. The legislation in multiple African countries mandates an incision in both triceps brachii muscles to detect the parasite as part of the normal post-mortem inspection, but this has an economic cost and is not universally mandated in other countries. The primary aim of this study was to investigate the epidemiology of bovine cysticercosis at an export abattoir in South Africa and determine the validity and cost of the triceps incision. Risk factors were investigated, and the effect of additional heart incisions on the current inspection. Four incisions were made into the heart in addition to the normal post-mortem inspection in 3353 carcasses. The proportion of positive animals with and without the cardiac and triceps incisions were compared using McNemar's chi-square tests, while risk factors were assessed using binary logistic regression. The economic impact of the triceps incision was estimated using a stochastic economic cost model. Thirty-three positive carcasses were identified for an apparent prevalence of 0.98 % (95 %CI, 0.69-1.36 %), while the true prevalence was estimated at 6.6 % (95 %CI, 4.3-8.8 %). All cysts were confirmed as T. saginata on histopathology with 70 % (95 %CI, 53-83 %) located in the heart. The additional cardiac incisions resulted in the detection of significantly more cases compared to the normal inspection method prevalence of 0.72 % (95 %CI, 0.47-1.05 %; P < 0.001). The apparent prevalence of T. saginata when omitting the triceps incision was not significantly lower compared to the prevalence when included in the inspection (P = 0.480). External feedlots (OR= 4.17, 95 %CI: 2.04-8.54, P < 0.001) and older animals (OR=3.90, 95 %CI: 1.17-13.03, P = 0.027) were associated with a positive detection. The current median annual financial cost to the food business operator from the triceps incision was estimated at $30387 (95 %CI: $0-$130696), with the proportion of deboned meat exported identified as the most important factor affecting cost (Spearman's rho=0.853). The identification of risk factors could aid in the development of a more effective risk-based inspection system. The current inspection should be modified to increase exposure of the heart and remove the triceps incisions. The latter should especially be considered given the minimal contribution to cysticercosis detection, the unsupported requirement for its inclusion specifically in Africa, and its economic impact, especially as beef exports increase.

Sarcocystis cruzi (Hasselmann, 1923) Wenyon, 1926: redescription, molecular characterization and deposition of life cycle stages specimens in the Smithsonian Museum

Currently, 7 named Sarcocystis species infect cattle: Sarcocystis hirsuta, S. cruzi, S. hominis, S. bovifelis, S. heydorni, S. bovini and S. rommeli; other, unnamed species also infect cattle. Of these parasites of cattle, a complete life cycle description is known only for S. cruzi, the most pathogenic species in cattle. The life cycle of S. cruzi was completed experimentally in 1982, before related parasite species were structurally characterized, and before the advent of molecular diagnostics; to our knowledge, no archived frozen tissues from the cattle employed in the original descriptions remain for DNA characterization. Here, we isolated DNA from a paraffin-embedded kidney of a calf experimentally infected with S. cruzi in 1980; we then sequenced portions of 18S rRNA, 28S rRNA, COX1 and Acetyl CoA genes and verified that each shares 99–100% similarity to other available isolates attributed to S. cruzi from naturally infected cattle. We also reevaluated histological sections of tissues of calves experimentally infected with S. cruzi in the original description, exploiting improvements in photographic technology to render clearer morphological detail. Finally, we reviewed all available studies of the life cycle of S. cruzi, noting that S. cruzi was transmitted between bison (Bison bison) and cattle (Bos taurus) and that the strain of parasite derived from bison appeared more pathogenic than the cattle strain. Based on these newfound molecular, morphological and physiological data, we thereby redescribed S. cruzi and deposited reference material in the Smithsonian Museum for posterity.

Comprehensive genetic diversity and molecular evolutionary analysis of Theileria annulata isolates based on TAMS 1 gene

Molecular epidemiological studies related to the phylogenetic characterization of Theileria annulata are important in delineating the evolutionary history of the parasite. In the current study, the Theileria annulata (T. annulata) merozoite surface antigen 1 (TAMS 1) gene from 14 bovine isolates of T. annulata originating from semi-arid zone of northern India were amplified and sequenced. TAMS 1 gene sequences (n= 337) reported from 16 countries were subsequently analyzed for haplotype network along with genetic diversity. A total of five haplotypes out of the 14 sequenced isolates and 92 haplotypes out of 337 worldwide sequences are documented in this study. Phylogenetic and molecular evolutionary analyses based on TAMS 1 gene sequences showed that T. annulata is dissipated across different countries and numerous strains are closely linked, even though they belong to different geographical locations. The nucleotide homology between 14 isolates from northern India varied between 91.3 and 100%, whereas it was between 31.5 and 100% when sequences across the globe were compared. Haplotype 14 was recognized as most widely distributed haplotype, with 46 isolates circulating in 10 countries. Globally, negligible genetic distance (FST˂0.15) and very high gene flow (Nm˃1) was found in the five populations of the world (South Asia, East Asia, West Asia, Europe and Africa), supporting the absence of clearly defined subgroups in the phylogenetic analysis. Significant negative values of neutrality tests; Tajima's D (D) and Fu and Li's F (F) provided evidence for recent population expansion through positive selection of advantageous variations.

Molecular detection of Theileria cervi in equids from México

Equine piroplasmosis is a parasitic illness caused by various protozoa of the Babesia and Theileria genera, which parasitize within red blood cells. The transmission of these pathogens occurs through certain genus of ticks, including Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus. In recent times, an increase in the identification of new Theileria species and genotypes has been observed. This is further complicated by the presence of mixed Theileria infections in both mammals and tick vectors, particularly in regions where wildlife and livestock share habitats and vectors. Therefore, the objective of this study is to document the occurrence of Theileria cervi in a non-typical host. A total of 88 horses (Equus caballus) and 10 donkeys (Equus asinus) were sampled in three municipalities in Veracruz, Mexico. Molecular techniques were employed to identify Babesia/Theileria through the amplification of a segment of the 18S-rDNA and hsp70 genes. The phylogenetic reconstruction grouped the obtained sequences into a monophyletic cluster alongside sequences of T. cervi. This work represents the first documented occurrence of T. cervi in equids. These findings have significant implications from an epidemiological point of view. In addition, further studies are needed to determine the distribution and pathogenicity of this species for domestic animals and to develop effective control strategies.

Effectiveness of a fixed-dose combination injectable (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) against Rhipicephalus microplus and sucking lice infesting cattle

Unmanaged tick and sucking lice infestations negatively impact the health and production potential of cattle. Described herein are two non-interference dose confirmation studies evaluating the efficacy of a single administration of a new fixed-dose combination injectable (FDCI) endectocide consisting of 0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride, against either laboratory-induced Rhipicephalus microplus infestations in Australia or naturally acquired sucking lice (Linognathus vituli) infestations in the US. This FDCI is available as Dectomax V® in Australia and New Zealand and as Valcor® in the United States. To evaluate therapeutic efficacy against R. microplus, 12 calves were each exposed to 10 infestations of ∼5000 larvae per infestation between Days -24 and -2. Calves were either treated on Day 0 with the FDCI or left untreated (control). Additional R. microplus infestations of ∼5000 larvae were conducted on Day 2 and then three times weekly to also evaluate persistent efficacy of the FDCI. Tick collections were conducted daily from Day -3. Group mean live tick counts, egg production, and egg viability were analyzed for significant differences between the two groups. To determine efficacy of the FDCI against lice, 24 cattle with active sucking lice infestations based on Day -7 counts were allocated to two groups and treated on Day 0 with either saline (control) or the FDCI. Lice counts were conducted weekly from Day 14 through 42 and again on Day 56. Mean group lice counts on each count day were compared between treatment groups. In the R. microplus study presented here, cattle in Queensland, Australia treated with the FDCI (Dectomax V®) showed > 90 % reduction in tick counts based on arithmetic means within 48 h of treatment when compared to untreated cattle, and counts were > 95 % reduced from post-treatment Day 5 through Day 30. In the sucking lice study conducted in the US, the FDCI (Valcor®) displayed 100 % efficacy against sucking lice infestations (L. vituli) from first count day (Day 14 post-treatment) through Day 35 and then 99.9 % efficacy through Day 56 post-treatment. No treatment-related adverse events were reported for cattle in either study. Using R. microplus and sucking lice as representative ectoparasites, these studies demonstrate the ectoparasite activity of doramectin is retained in the new FDCI.

Prevalence of Cryptosporidium infection and associated risk factors in calves in Egypt

Cryptosporidium is one of the causative parasitic agents that causes gastrointestinal diseases in calves. The parasite poses a zoonotic risk to immunocompromised individuals and children. Thus, this study aimed to determine the prevalence of Cryptosporidium infection in calves in three Egyptian governorates situated in Nile Delta and assess the associated risk factors. The Cryptosporidium oocysts were detected in 81 out of 430 calves (18.84%). In addition, the univariant analysis showed that age, feeding source, hygienic status, presence of diarrhea and contact with other animals were significantly (P < 0.05) associated with Cryptosporidium prevalence in calves. Furthermore, the risk factors related with Cryptosporidium prevalence were age (OR 1.96, 95%CI 0.97-3.94), feeding on milk and pasture (OR 2.07, 95%CI 1.15-3.72), poor hygienic condition (OR 2.25, 95%CI 1.28-3.94), presence of diarrhea (OR 2.47, 95%CI 1.23-4.96) and contact with other domestic animals (OR 2.08, 95%CI 1.24-3.50). In addition, the PCR assay targeting 18srRNA showed that the most prevalent species among calves was C. parvum. Although additional researches are required to understand the most effective steps that farmers and veterinary professionals should take to decrease the occurrence of Cryptosporidium infection.

Multinomial logistic regression based on neural networks reveals inherent differences among dairy farms depending on the differential exposure to Fasciola hepatica and Ostertagia ostertagi

Fasciola hepatica and Ostertagia ostertagi are cattle parasites with worldwide relevance for economic outcome as well as animal health and welfare. The on-farm exposure of cattle to both parasites is a function of host-associated, intrinsic, as well as environmental and farm-specific, extrinsic, factors. Even though knowledge on the biology of both parasites exists, sophisticated and innovative modelling approaches can help to deepen our understanding of key aspects fostering the exposure of dairy cows to these pathogens. In the present study, multiple multinomial logistic regression models were fitted via neural networks to describe the differences among farms where cattle were not exposed to either F. hepatica or O. ostertagi, to one parasite, or to both, respectively. Farm-specific production and management characteristics were used as covariates to portray these differences. This elucidated inherent farm characteristics associated with parasite exposure. In both studied regions, pasture access for cows, farm-level milk yield, and lameness prevalence were identified as relevant factors. In region 'South', adherence to organic farming principles was a further covariate of importance. In region 'North', the prevalence of cows with a low body condition score, herd size, hock lesion prevalence, farm-level somatic cell count, and study year appeared to be of relevance. The present study broadens our understanding of the complex epidemiological scenarios that could predict differential farm-level parasite status. The analyses have revealed the importance of awareness of dissimilarities between farms in regard to the differential exposure to F. hepatica and O. ostertagi. This provides solid evidence that dynamics and relevant factors differ depending on whether or not cows are exposed to F. hepatica, O. ostertagi, or to both.