Eimeria infections in cows in the periparturient phase and their calves: oocyst excretion and levels of specific serum and colostrum antibodies

Molecular diagnosis and phylogenetic insights of Eimeria species infecting buffaloes (Bubalus bubalis) in Meghalaya's subtropical hilly region, India

Coccidiosis is an intestinal infection caused by Eimeria spp. that results in economic losses owing to morbidity and mortality in young buffalo calves. This study aimed for molecular diagnosis and phylogenetic analysis of Eimeria spp. in buffaloes of Meghalaya's sub-tropical mountainous terrain. Fresh buffaloes' fecal samples were collected from buffalo farms of Umling, Umsning and Bhoirymbong blocks, Ri Bhoi, Meghalaya and screened for Eimeria oocysts using flotation and modified McMaster methods. Fecal sample examination revealed 27.44 % (87/317) infection in buffaloes. Age wise, 64.44 % (29/45), 25.35 % (36/142) and 16.92 % (22/130) infections were recorded in <6 months, 6 months to 1 year and 1-2 year old buffaloes, respectively. Morphological characterization of Eimeria spp. revealed E. bovis (21.83 %), E. bareillyi (18.39 %), E. zuernii (11.49 %), E. ellipsoidalis (3.44 %) and mixed infection (44.82 %). Amplification of ITS-1 gene confirmed Eimeria spp. (410 bp), E. bovis (238 bp) and E. zuernii (344 bp). Phylogenetic analysis of E. bovis Umiam isolate revealed that these were closely related to the E. bovis isolate from South Korea (MH245198.1), and Turkey (KU351711.1) and distantly related to the isolates from Jammu and Kashmir (OQ103422.1) and Uttar Pradesh, Mathura (OK486542.1). E. zuernii isolate from Umiam, Meghalaya was observed to be phylogenetically close to the isolates from South Korea (MH245202.1), Japan (LC171339.1) and Turkey (KU351715.1), whereas phylogenetic divergence was observed between, E. zuernii isolate from Umiam, Meghalaya with isolates of Andhra Pradesh, Tirupati (MN601278.1) and Jammu and Kashmir (OQ103424.1). Therefore, treatment and effective control strategies should be implemented immediately to prevent spread of infection in the buffaloes.

Viability time of sporulated oocysts of bovine Eimeria spp. in water and efficacy of disinfectants in a region with tropical climate

The water can be a significant risk factor for the occurrence of cattle eimeriosis on farms located in tropical climate regions. This study aimed to assess the viability period of sporulated oocysts of bovine Eimeria spp. in water containing organic matter and to evaluate the efficacy of disinfectants against sporulated oocysts of this protozoa. Two experiments were conducted, each comprising in vitro and in vivo evaluations. In Experiment 1, the viability period of oocysts sporulated in buckets containing a solution composed of a mixture of feces with oocysts, water, and potassium dichromate was assessed. Quantifications and identification of Eimeria spp. oocysts were performed on days + 30, + 60, + 90, and every 30 days thereafter until no more oocysts were detected. Naïve calves were inoculated with this solution kept in the bucket for 6 and 12 months. In Experiment 2, the efficacy of various disinfectants (acetic acid, sodium hypochlorite, ethanol + acetic acid, and ammonia quaternary) against a new solution of sporulated oocysts and pH changes over time (10', 30', and 24 h) were evaluated in the laboratory. The most effective disinfectant was used to treat the water solution and inoculate the calves, and its efficacy was calculated. In Experiment 1, Eimeria spp. oocysts remained viable in the solution for up to 12 months. E. zuernii persisted until the end of the study period. Calves inoculated with the solution kept in the buckets for 6 and 12 months excreted at least four Eimeria species (E. zuernii, E. bovis, E. ellipsoidalis, and E. cylindrica). In Experiment 2, among the tested disinfectants, 3% acetic acid demonstrated the highest efficacy (10' = 80.9%; 30' = 87.9%; 24 h = 91.7%). The pH values of the solutions containing acetic acid ranged from 2.4 to 3.5. Calves that received the inoculum treated with 3% acetic acid did not excrete Eimeria spp. oocysts in feces during the study period (efficacy = 100%). In contrast, all animals in the control group excreted Eimeria spp. oocysts in feces. Future studies should be carried out to better understand the possible effects of cattle drinking water with 3% acetic acid.

Does parity order or cow antibody level influence the humoral immunity of calves for cattle anaplasmosis?

Anaplasmosis is a widely distributed vector-borne disease of cattle caused by the bacteria Anaplasma marginale, which may lead to severe losses in beef and dairy cattle production. Anecdotal information among farmers suggested that some cows may deliver calves more resilient to anaplasmosis. To investigate this, we tested two hypotheses: (i) whether the parity order or (ii) cow antibody levels may influence the humoral immunity of pre-weaning calves against cattle anaplasmosis. For this study, we sampled 170 cattle (Bos taurus taurus, Angus breed) on a farm in Southern Brazil, comprising 85 cows (50 multiparous and 35 primiparous) and their 85 calves (50 days old). Antibodies against A. marginale were investigated using iELISA. Eighty percent of the animals were considered seropositive (100% of the cows and 60% of the calves). There was no significant difference in seroprevalence between calves from primiparous and multiparous cows. However, calves from multiparous cows exhibited higher antibody levels. To address the second question, we classified cows based on their antibody levels to A. marginale (high or low). Calves from cows with high antibody levels also showed elevated antibody levels against A. marginale. Furthermore, calves from cows with high antibody levels had approximately four times greater odds of being seropositive for A. marginale at 50 days old than those born to mothers with low antibody levels. In conclusion, the calf's antibody level against A. marginale appears to be related to the cow's parity order and the mother's antibody level.

Dynamics of protozoal excretion in the faeces of calves during the first 28 days after arrival at the fattening farm indicate infection before regrouping and show poor temporal correlation with diarrhoea

BACKGROUND

Calves in dairy cattle production in Switzerland are transported to a fattening farm at the age of 3-5 weeks, and frequently suffer from diarrhoea within the first 14 days after arrival. To characterise the role of intestinal protozoa in this, we investigated the excretion dynamics of Eimeria, Cryptosporidium and Giardia during the first 28 days after the arrival and regrouping of calves at fattening farms.

METHODS

A total of 610 faecal samples from 122 calves (mean age 37.3 days; mean body weight 79.8 kg) were collected on seven different fattening farms during the first 28 days after the arrival and regrouping of the animals. The farms were visited between January and April (cold season; n = 4) and between June and August (warm season; n = 3). The samples were collected rectally on days 1, 4, 7, 14 and 28, assessed for consistency, and analysed using the McMaster method for quantitative determination of the number of Eimeria oocysts per gram of faeces (OPG), flotation for morphological differentiation of the unsporulated Eimeria oocysts, a concentration method for the semi-quantitative determination of Giardia cysts, and modified Ziehl-Neelsen staining for semi-quantitative determination of Cryptosporidium oocysts.

RESULTS

Overall, 50.8% (62/122) of the animals had diarrhoea during the study period. However, the faecal excretion of protozoal pathogens was neither associated with diarrhoea nor with body weight gain of the animals. Altogether, 90.2% (110/122) of the calves were Eimeria positive. Eimeria zuernii was excreted by 51 (41.8%) and Eimeria bovis by 68 (55.7%) animals. In the warm season more animals tested positive for Eimeria and OPGs were higher than in the cold season. There was no correlation between the age of the calves and the OPG values. Overall, 64.8% (79/122) of the calves excreted Eimeria oocysts within the first 7 days, indicating that they had been infected with the parasite on the dairy farm of origin. Eighty-nine calves (73.0%) excreted Giardia cysts, with more positive animals in the cold (80.3%) compared with the warm season (64.3%). Only Giardia duodenalis assemblage E was identified. Cryptosporidium oocysts were microscopically detected in 14 animals (11.5%) on five farms. Cryptosporidium spp. were present in a total of 12 animals, i.e. Cryptosporidium parvum in nine, Cryptosporidium ryanae in two, and Cryptosporidium bovis in one animal.

CONCLUSIONS

A better understanding of the temporal dynamics of protozoal infections in calves is helpful for the implementation of appropriate measures to protect the health of these animals at a critical phase in their lives. Our results indicate that factors other than those examined in the present study contributed to the onset of diarrhoea in the calves.

A pilot study for the isolation of Eimeria spp. oocysts from environmental straw samples in comparison with individual faecal examination of fattening calves

The diagnosis of eimeriosis in calves mainly relies on the presence of diarrhoea and the excretion of Eimeria oocysts in the faeces. Restraining the animals to collect rectal samples for diagnostic purposes is stressful and time-consuming. The aim of this study was to evaluate a method for the quantification of oocysts in environmental barn straw samples. To investigate the recovery rate of the method, straw and Eimeria negative faeces were spiked with Eimeria oocysts in plastic bags and mixed with water and 0.05% Tween 20 (v/v); the liquids were filtered twice through sieves (mesh size 300 and 52 μm), centrifuged and the number of oocysts in the sediment determined using a McMaster counting chamber. A recovery rate of 52.4% (95% confidence interval: 48.2-56.5%) was obtained. In the following, field straw (n = 156) and individual faecal samples (n = 195, also analysed by McMaster counting chambers) were collected on four different farms. Eimeria oocysts were present on all farms in faecal (84/195, 43.1%) and straw samples (119/156, 76.3%). In 37 (23.7%) straw samples, sporulated oocysts were observed, with a sporulation rate ranging from 0 to 40%. Despite high variability between farms and examination days, mean numbers of oocysts in the straw positively correlated with mean numbers of oocysts excreted in the faeces (ρ_Spearman = 0.60). The examination of environmental straw samples may represent an easy-to-perform, non-invasive, inexpensive preliminary diagnostic approach for surveillance of eimeriosis at group level, having the potential to assess the infection pressure.

Prevalence and risk factors of coccidiosis in calves from Veracruz, México

The objectives of the present study were: (1) to determine the prevalence of Eimeria spp. sporulated oocysts in calves from 26 Municipalities in the Central Zone of the State of Veracruz, Mexico, (2) to identify the Eimeria spp. infecting calves, and (3) to identify the risk factors associated with the presence of Eimeria spp. in tropical cattle. A total of 930 individual fecal samples were analyzed by using the McMaster technique; then, oocysts were maintained in 2.5% potassium dichromate to allow sporulation. The general prevalence of calves with Eimeria spp. oocysts was 39.7% (370/930). Of a total of 10 identified species, Eimeria canadensis was the most observed, followed by Eimeria bovis and Eimeria zuernii. The statistical analysis showed an association between the age of the calves (5 to 9 months), the presence of other animals, the physiographic regions and the restricted type of husbandry with the presence of Eimeria spp. in calves (P<0.05). Protective risk factors, such as: routine coprological analysis was also associated with a decrease in infection. These data demonstrate the presence of coccidia in cattle from the State of Veracruz, additionally to the necessary measures that must be taken to control this parasitosis.

Gastrointestinal parasitic infections in intensive dairy cattle breeding: Update on the epidemiology and associated risk factors in northern Italy

Parasitic infections such as Strongylida and Eimeria still represent a major health problem of dairy cattle impacting their health, welfare, and productivity. In view of the scarcity of data on risk factors contributing to the spread of parasitic infections in cattle breeding, an epidemiological study in intensive dairy farms in northern Italy was planned. 495 animals (lactating and dry cows, heifers, and calves) from 19 farms were enrolled in the study. Individual fecal samples were analyzed by a quantitative copromicroscopic analysis to detect the number of Strongylida eggs or Eimeria oocysts per gram of faeces (EPG/OPG). Data concerning management, sanitary and biosecurity measures were collected using a questionnaire; a management measures score (MMS) was also calculated. The possible influence of risk factors on Strongylida and Eimeria was thus assessed by statistical analysis using generalized linear mixed models (GLMMs). Eimeria spp. was the most frequently detected parasitic taxon (herd and individual prevalence: 89.5% and 46.2%, respectively), followed by Strongylida (herd and individual prevalence: 63.1% and 16.6%, respectively). The presence of Strongylida resulted associated to the productive category (p-value = 0.028), with heifers and dry cows at higher risk of infection than lactating cows and calves, and to the MMS (p-value = 0.007). Higher prevalence values were recorded in farms with intermediate or low MMS compared to those with optimal MMS. As regard Eimeria infection, a greater effect of MMS on OPG counts was recorded in calves when compared to those recorded in heifers (OR = 0.228, p-value = 0.003) and dry cows (OR = 0.241, p-value = 0.009). Gastrointestinal parasitic infections still remain an underestimated problem in intensive dairy cattle breeding. MMS may help in the choice of strategies aimed at minimizing the impact of parasites on animal health, thus improving the productivity of the entire herd.

Eimeria infections in domestic and wild ruminants with reference to control options in domestic ruminants

Eimeria infections are commonly seen in a variety of mammalian hosts. This genus of unicellular sporozoan parasites causes significant disease (coccidiosis) in different livestock species leading to economic losses for agricultural producers. Especially the production of cattle, sheep, and goat is strongly dependent on efficient coccidiosis control. However, many other livestock hosts like, e.g., camelids, bison, rabbits, and guinea pigs may benefit from reduced parasite transmission and targeted control measures as well. Besides livestock, also wildlife and pet animals may be affected by Eimeria infections resulting in clinical or subclinical coccidiosis. Wildlife herd health is crucial to conservation efforts, and Eimeria species are a prevalent pathogen in multiple mammalian wildlife species. This review aims to highlight the epidemiology of mammalian Eimeria infections in both wild and domestic ruminants, including host specificity, transmission, survival of environmental oocysts, occurrence, and risk factors for infection. Understanding general drivers of Eimeria infection may support adequate livestock and wildlife management. Furthermore, control options for livestock with reference to management factors, drug application, and alternative approaches are discussed. The goal of Eimeria control should be to reduce pathogen transmission in different host species and to improve sustainable livestock production. Controlling Eimeria infections in livestock is important considering both their animal welfare impact and their high economic relevance.

Prevalence and risk factors associated with Eimeria species infection in cattle of different geographical regions of Indonesia

Background and Aim:

Eimeria spp. are gastrointestinal protozoans that affect animal productivity, thereby causing symptoms that range from bloody diarrhea to death. These symptoms cause economic losses to farmers. The distribution of Eimeria spp. in cattle has, therefore, been reported to have spread widely, especially in the tropics and subtropics. Indonesia is a tropical country at high risk of Eimeria infections. This study aimed to identify the prevalence and risk factors related to the levels of eimeriosis in beef cattle originating from different geographic areas in Indonesia.

Materials and Methods:

Here, 817 fecal samples were collected from beef cattle in Indonesia, including 282 calves, 535 adults, 530 males, and 287 females. In addition, 156 semi-intensively and 661 intensively managed cattle were randomly collected. Then, fecal samples were analyzed by parasitology examinations.

Results:

Screening examination using the sugar flotation modification method showed that Eimeria spp. were prevalent in Indonesia, as 65.4% of the bacterial strain was detected. The prevalence of identified Eimeria spp. in Indonesia was highest in North Maluku (Maluku Island) (94.1%), whereas the lowest levels were observed in West Java (24.0%) (Java Island). The prevalence was also found to be higher in males (79.3%) than females (51.9%). Similarly, levels in semi-intensively managed cattle (66.7%) were higher than those subjected to intensive management (65.9%). However, its prevalence in calf and adult cattle was similar.

Conclusion:

Bovine eimeriosis spp. were detected at high prevalence in Indonesia, and high-level risks were observed in infected males, including those under the semi-intensive management. In addition, although the results from oocyst examinations were based on qualitative analysis, the endemicity levels of Eimeria spp. among farms in Indonesia should be considered because Eimeria spp. were distributed in most parts of Indonesia. Based on the results of this study, we provide the first information about the prevalence of bovine eimeriosis from different geographical locations in Indonesia, which have differing climates associated with the level of the existing risk factors. Hence, farmers are advised to pay more attention to strict biosecurity techniques on their farms, thereby favoring the early control of bovine eimeriosis.

Investigation and molecular identification of Eimeria sp. sampled from captive forest musk deer

Forest musk deer (Moschus berezovskii) is an endangered, protected species in China. Intestinal coccidiosis is a significant problem for captive forest musk deer. However, there are few reports on the prevalence and molecular characteristics of Eimeria sp. in forest musk deer. We sought to investigate the prevalence of Eimeria sp. in forest musk deer in the Sichuan and Shaanxi provinces in China. We also investigated the molecular characteristics of Eimeria sp. by analyzing the 18S rRNA gene. We collected a total of 328 fecal samples from forest musk deer on seven farms throughout the Sichuan and Shaanxi provinces. We extracted this parasite’s DNA and used this as a template for nested PCR amplification. The 18S rRNA gene fragment was associated with the plasmid vector, and these products were introduced into Escherichia coli (DH5α). The cultured bacterial solution was used as a PCR reaction template for identification purposes. We collected 328 fecal samples from forest musk deer in Lixian (n = 54), Maoxian (n = 52), Ma’erkang (n = 49), Dujiangyan (n = 55), Hanyuan (n = 41), Luding (n = 36) and Weinan (n = 41). One hundred ninety-eight (60.37%) fecal samples tested positive for Eimeria sp. . In our analysis of the 18S rRNA gene we found 34 types of Eimeria sp. with a similarity of 90.5–100%. We constructed a phylogenetic tree based on the parasite’s 18S rRNA gene sequence. Our findings indicated that the Eimeria sp. that parasitized the intestinal tract of forest musk deer was closely related to Eimeria alabamensis from Bos taurus and Eimeria ahsata from Ovis aries. To the best of our knowledge, ours was the first investigation and molecular identification of Eimeria sp. sampled from captive forest musk deer in China. Our results provide epidemiological data for the monitoring and prevention of Eimeria sp. in captive forest musk deer.

Prevalence and infection risk factors of bovine Eimeria in China: a systematic review and meta-analysis

Eimeria spp. cause the disease coccidiosis, which results in chronic wasting of livestock and can lead to the death of the animal. The disease, common worldwide, has caused huge economic losses to the cattle industry in particular. This is the first systematic review and meta-analysis of the prevalence of bovine Eimeria in China. Our search of five databases including PubMed, ScienceDirect, China National Knowledge Infrastructure (CNKI), Chongqing VIP, and Wan Fang for articles published up to February 29, 2020 on the prevalence of Eimeria in cattle in mainland China yielded 46 articles, in which the prevalence of cattle ranged from 4.6% to 87.5%. The rate of bovine Eimeria infection has been decreasing year by year, from 57.9% before 2000 to 25.0% after 2015, but it is still high. We also analyzed the region, sampling years, detection methods, feeding model, seasons, and species of bovine Eimeria. We recommend that prevention strategies should focus on strengthening detection of Eimeria in calves in the intensive farming model.

Eimeria spp. in naturally infected beef cattle: Dynamics of oocysts excretion, prevalence, and comparison between parasitological diagnostics

Eimeria spp. infections cause mortality, reduced well-being, and substantial economic losses implications for cattle production worldwide. The present work followed up the excretion of Eimeria spp. oocysts in two naturally infected beef herds, from two different properties, to investigate the dynamics of oocyst excretion and the prevalence of Eimeria spp. in different animal categories and seasons of the year (rainy season - October to April; dry season - May to September). Even that, the species of Eimeria were identified and the parasitological techniques of Gordon and Whitlock modified and Mini-FLOTAC were used. In both herds, animals up to 14 months had a mean total OPG counts higher than older animals (after 15-16 months of age), and the species E. zuernii and E. bovis were more frequently identified, the first species being more frequent in animals from 1 to 2 months of age, while E. bovis prevailed from three months old. On property 1, the highest mean OPG counts (P ≤ 0.05) were obtained between October 2017 and September 2018, with the highest mean OPG counts in October 2017, when the animals were aged between 4-5 months. The prevalence of the pathogen on property 1 was 59.16 % and 43.62 % in the rainy and dry season, respectively, a higher parasitic load (P ≤ 0.05) was verified in the rainy season. On property 2, the mean OPG counts of Eimeria spp. was higher (P ≤ 0.05) in animals between 8-16 months, with the highest peak in November 2019, when they were one year old. The on-site prevalence during the rainy season on property 2 was 53.09 % and 49.79 % on dry season, and no difference (P = 0.92) in the mean OPG counts of Eimeria spp. during the seasons. There was a difference (P ≤ 0.05) in the count of oocysts in females after 18 months of age than males, which was probably due to the increase in animal density. Both tested techniques can be used for quantification of the excretion of oocysts of Eimeria spp. in cattle feces showing the same OPG mean count (r = 0.9287; p = 0.0025; R² = 0.8625). Mini-FLOTAC showed higher prevalence for Eimeria spp., however, can be an obstacle depending on the number of fecal samples that need to be processed.

COMPARISON OF NATURALLY OCCURRING EIMERIA INFECTIONS IN ALPINE AND NERA DI VERZASCA GOAT BREEDS REARED IN A SUB-ALPINE ENVIRONMENT

The present study aimed to describe the natural trend of Eimeria spp. oocysts shedding in different breeds of adult goats raised in a sub-Alpine ecosystem by quantitative copromicroscopic analysis. A 1-yr long longitudinal study was planned in a goat herd composed of non-native (Alpine) and autochthonous (Nera di Verzasca) breeds. FLOTAC double technique was implemented to analyze individual fecal samples collected monthly from 2 groups (non-native and native) of 10 goats each. A generalized linear mixed model, in which each goat was included as a random intercept effect, identified 4 predictors of logarithmically transformed oocysts per gram shedding: the number of days from parturition (F = 27.744; P < 0.001), the interaction between the goat breed and the number of days from parturition (F = 8.407; P = 0.004), the interaction between the number of days from parturition and the number of parturitions (F = 6.371; P = 0.012), and the interaction between the monthly rainfalls and temperatures (F = 4.536; P = 0.023). These results indicate that the physiological status (number of days from parturition) of adult goats and its interaction with other individual features (number of parturitions and breed) can affect Eimeria spp. oocysts shedding. Besides, a combination of climatic variables can pose a risk for Eimeria spp. infection in goats reared in the sub-Alpine environment.

Efficiency of 5% toltrazuril in the metaphylactic treatment of coccidiosis in naturally infected and extensively reared beef calves

Eimeria spp. infection is one of the main diseases that affect young cattle in beef and dairy herds, leading to economic losses and compromising the performance and growth of animals. This study aimed to evaluate the effectiveness of different protocols of metaphylactic treatment with 5% toltrazuril (15 mg/kg) in naturally infected, extensively reared beef calves from birth to 1 year of age. We used 92 calves aged up to 2 weeks of life, initially divided into two experimental groups: treated and control. The animals were evaluated fortnightly with individual count of oocysts per gram of feces (OPG) tests until weaning; thereafter, they were again divided into four subgroups: I-treated at both birth and weaning; II-treated at birth but not treated at weaning; III-not treated at birth but treated at weaning; and IV-neither treated at birth nor at weaning (control). During the experimental period, the animals were evaluated for weight gain, excretion of oocysts, and presence of pathogenic species of Eimeria spp. In the first stage of the study, less oocysts were excreted in the treated group for up to 75 days and at 150 days of age (p < 0.05). In the final stage of the study, significant differences occur between groups I and II, I and IV, II and III, and III and IV (p = 0.3512), in the collection 20 days after treatment. Eimeria bovis was the most frequently identified species during the experimental period. Moreover, there was a positive correlation between the presence of diarrhea in the calves and the number of oocysts excreted, treated group (p = 0.0092) and untreated group (p = 0.2). There was no significant difference in weight gain of animals in any of the study periods (p > 0.05).

Oocyst shedding patterns of Eimeria species and their association with management and performance at ten rose veal starter farms in the Netherlands

Coccidiosis at rose veal starter farms is often diagnosed however, this was the first study performed considering this topic on this type of rearing unit. The objective of this study was to identify Eimeria species faecal shedding patterns at ten Dutch rose veal starter farms during rearing. Further objectives were to investigate associations with (gut) health, production and management decisions. Faecal samples from twelve randomly selected calves per farm were collected weekly during 9 consecutive weeks. Thereafter samples were pooled in a predetermined composition of six. These calves were clinically evaluated every sample visit and weighed at the first and last visit. Laboratory tests included a flotation test of the samples. If this yielded Eimeria oocysts, both oocysts per gram feces (OPG) and species differentiation were established using a modified McMaster method. Management parameters and technical herd results were identified after finalizing the study period using a questionnaire. Studied patterns in oocyst shedding included the pool's cumulated OPG, maximum OPG level and the number of sample days (SD) that OPG exceeded a confirmed level. Statistical analysis included univariate and multivariate analysis. Associated (p < 0.10) OPG patterns considering rumen fill, faecal consistency and average daily weight gain (ADG) were tested using a model with herd included as random effect. RESULTS: on all ten farms E. alabamensis, E.bovis and E. zuernii besides non-pathogenic species were identified, often as mixed infections. Peak OPG occurred predominately at SD 21 and 28 (E. alabamensis and E. bovis), and at SD 42 (E. zuernii). In 16 pools, OPG levels ≥500 for E. bovis or E. zuernii, were found. Significant correlation (p < 0.0001) showed between the log₁₀ OPG of pathogenic Eimeria and of all Eimeria species. Multivariate analysis showed significant correlation between cumulative faecal consistency scores and cumulative log₁₀ OPG of pathogenic Eimeria species (β = 0.16; p = 0.008). Pools exceeding 750 OPG for E. bovis showed 93 g lower ADG and pools experiencing ≥2 SD with >1000 OPG for E. alabamensis 141 g lower ADG. From the questionnaire we identified lower cumulated OPG of all Eimeria species except for E. bovis at farms where the units were cleaned before arrival of the calves. CONCLUSION: As a rule, on Dutch rose veal starter farms, mixed Eimeria infections occur, but shedding patterns differ between farms. Clinical and growth performance is related to OPG patterns found. Cleaning units before arrival of calves lowers oocyst shedding during the rearing period.

Eimeria ninakohlyakimovae casts NOX-independent NETosis and induces enhanced IL-12, TNF-α, IL-6, CCL2 and iNOS gene transcription in caprine PMN

Eimeria ninakohlyakimovae represents a highly pathogenic coccidian parasite causing severe haemorrhagic typhlocolitis in goat kids worldwide. NETosis was recently described as an efficient defense mechanism of polymorphonuclear neutrophils (PMN) acting against different parasites in vitro and in vivo. In vitro interactions of caprine PMN with parasitic stages of E. ninakohlyakimovae (i. e. oocysts and sporozoites) as well as soluble oocyst antigens (SOA) were analyzed at different ratios, concentrations and time spans. Extracellular DNA staining was used to illustrate classical molecules induced during caprine NETosis [i. e. histones (H3) and neutrophil elastase (NE)] via antibody-based immunofluorescence analyses. Functional inhibitor treatments with DPI and DNase I were applied to unveil role of NADPH oxidase (NOX) and characterize DNA-backbone composition of E. ninakohlyakimovae-triggered caprine NETosis. Scanning electron microscopy (SEM)- and immunofluorescence-analyses demonstrated that caprine PMN underwent NETosis upon contact with sporozoites and oocysts of E. ninakohlyakimovae, ensnaring filaments which firmly entrapped parasites. Detailed co-localization studies of E. ninakohlyakimovae-induced caprine NETosis revealed presence of PMN-derived DNA being adorned with nuclear H3 and NE corroborating molecular characteristics of NETosis. E. ninakohlyakoimovae-induced caprine NETosis was found to be NOX-independent since DPI inhibition led to a slight decrease of NETosis. Exposure of caprine PMN to vital E. ninakohlyakimovae sporozoites as well as SOA resulted in up-regulation of IL-12, TNF-α, IL-6, CCL2 and iNOS gene transcription in stimulated PMN. Since vital E. ninakohlyakimovae-sporozoites induced caprine NETosis, this effective entrapment mechanism might reduce initial sporozoite epithelial host cell invasion during goat coccidiosis ultimately resulting in less macromeront formation and reduced merozoites I production.

Epidemiological study on calf diarrhea and coccidiosis in dairy farms in Bahir Dar, North West Ethiopia

Background

A longitudinal prospective study was conducted from October 2017 to April 2018 on calf diarrhea and coccidiosis in dairy farms in Bahir Dar, North West Ethiopia with the objectives of determining the incidence of calf diarrhea and calf coccidiosis from diarrheic calves, assessing the major risk factors associated with calf diarrhea and coccidiosis and identifying the existing Eimeria species. A total of 237 calves, 86 calves from 52 smallholder dairy farms and 151 calves from 8 large dairy farms, were used for this study. Fresh fecal samples were collected from 86 diarrheic calves for identification of Eimeria species.

Results

Overall incidences of calf diarrhea and coccidiosis found in this study were 33.5 and 20.1%, respectively. In total, 19 potential risk factors were investigated for their association with calf diarrhea and coccidiosis from diarrheic calves using Cox regression. Age of calf (HR = 2.057, P = .002), body condition (HR = 1.802, P < .001), house condition (HR = 2.072, P = .004) and age at first colostrum feeding time (HR = 2.107, P = .002) were found significantly (P < 0.05) associated with the risk of diarrhea by multivariate Cox regression. Among the risk factors tested, age (HR = 13.36, P < .001) and sex of calves (HR = 3.500, P = .020) were found significantly (P < 0.05) associated with coccidiosis by multivariate Cox regression. A total of nine Eimeria species were identified. E. bovis (28.6%), E. zuernii (19.0%) and E. auburnensis (14.3%) were the most common Eimeria species encountered.

Conclusion

The incidence of calf diarrhea and coccidiosis was high in the dairy herds in North West Ethiopia. Therefore, sound dairy calf management practices are needed to mitigate risk factors for calf diarrhea and coccidiosis with a view to reducing the incidence of calf diarrhea and coccidiosis in Ethiopian dairy farms.

Epidemiological survey and risk factor analysis on Eimeria infections in calves and young cattle up to 1 year old in Colombia

A large-scale cross-sectional epidemiological study was conducted to evaluate prevalence, species diversity, and associated risk factors of Eimeria infections in 55 cattle farms across seven states of Colombia, including subtropical and tropical regions. In total, 1333 fecal samples from young animals (< 1 year of age) were examined at a single sampling date from August 2016 to December 2016. Flotation and McMaster techniques were conducted for parasitological investigation. Excreted Eimeria oocysts were allowed to sporulate in vitro and thereafter identified to species level based on morphological and morphometric characteristics. The overall Eimeria prevalence was 75.5% (1006/1333), with no difference observed between age categories. In total, 13 different Eimeria species were identified. The most prevalent species was E. bovis (33.5%), followed by E. auburnensis (12.5%) and E. zuernii (11.9%). Analysis of extrinsic associated risk factors revealed the floor type, feeding system, watering system, and herd size as significant (p < 0.05) risk factors for Eimeria spp. infections. Based on these data, it can be assumed that bovine coccidiosis infections occur ubiquitously in the country and might play an important role especially in its subclinical form by affecting production parameters in conventional cattle management systems.

Bovine coccidiosis cases of beef and dairy cattle in Indonesia

The number of bovine coccidiosis cases is generally high and distributed worldwide. It can reach up to 100% in the early weeks of age in calves and has a corresponding impact on further cattle development and the economic outcome. For these reasons, this study was conducted to detect the presence of Eimeria spp. oocysts followed by morphologically species characterization in different breeds of beef and dairy cattle. These breeds were reared by rural farmers in 9 provinces in Indonesia from March to October 2017. A total of 2150 fecal samples were collected, along with farmer knowledge about coccidiosis through interviews. Results show that prevalence varied as indicated by the following regions: Riau (68.73%), South Sumatera (78.34%), Banten (63.73%), Special Region of Yogyakarta (54.69%), East Java (63.89%), Bali (83.34%), West Nusa Tenggara (78.43%), Central Kalimantan (72.46%), and South Sulawesi (85.07%). The overall prevalence of bovine coccidiosis in all provinces sampled was 72.07%. Eight species of Eimeria spp. were identified, namely, E. auburnensis (52.11%), E. bovis (81.89%), E. bukidnonensis (18.44%), E. canadensis (38.22%), E. cylindrica (31.67%), E. zuernii (60%), E. ellipsoidalis (10.11%), and E. alabamensis (11.67%). The highest prevalence was found in E. bovis compared with any other Eimerias (P ≤ .0001) followed by E. zuernii. Most of the interviewed farmers in this study did not know about coccidia, especially Eimeria spp. in cattle. They were more familiar with worm infections because of both their experience and knowledge. The distribution of cattle with ages <6 months, 6-18 months, and >18 months exhibited 97%, 81%, and 38% infection, respectively. Based on these results, the authors saw the necessity to inform farmers about bovine coccidiosis as well as the veterinarian regarding better preventive and curative treatments.

Long-term use of yeast fermentation products in comparison to halofuginone for the control of cryptosporidiosis in neonatal calves

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Prophylactic effect of halofuginone against bovine cryptosporidiosis is equivocal.

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Saccharomyces cerevisiae fermentation products (SCFP) are feed additives.

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SCFP feeding showed similar clinical effects in newborn calves as halofuginone.

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Pre-weaning supplementation with SCFP may be an alternative in bovine cryptosporidiosis.

The objective of this study was to compare the effect of non-GMO Saccharomyces cerevisiae fermentation products (SCFP) with that of a halofuginone treatment against Cryptosporidium parvum infection in pre-weaned calves on a commercial dairy farm. A total of 123 neonatal female calves, housed in individual hutches, were enrolled sequentially based on date of birth in 41 blocks of 3 animals each. Calves within each block were allocated to one of 3 treatments: remaining untreated, fed with SCFP (Diamond V SmartCare^® at 1 g/d in milk and NutriTek^® at 5 g/d in starter grain) for the first 63 days of life, or treated with halofuginone (0.1 mg/kg/d) for the first 7 days of life. Fecal samples collected on days 4–21 post-partum were examined for both Cryptosporidium oocysts and coproantigen. The presence and intensity of diarrhea were monitored by scoring daily for the first 4 weeks of life. Calves were weighed at 0, 21, 42 and 63 days of age. Almost all calves were Cryptosporidium-positive at least once during the study. Halofuginone significantly reduced the number of Cryptosporidium-positive fecal samples as compared to the two other groups. Based on the coproantigen scores, both halofuginone and SCFP feeding significantly reduced the intensity of Cryptosporidium infection as compared to the untreated group. Diarrhea was recorded in almost all calves at least once. Neither the proportion of diarrheic calves nor the intensity and duration of diarrhea differed among the 3 treatment groups significantly. The mean daily weight gain during the first 3 weeks of life was significantly lower in halofuginone treated calves than in both other groups; however, at the end of the study period the total weight gain did not significantly differ among the 3 treatment groups. In conclusion, the clinical results and weight gains of pre-weaning supplementation with the SCFP were neither better nor worse than the 7-day halofuginone treatment suggesting that the SCFP feeding may be from the clinical point of view a natural alternative measure, instead of halofuginone treatment, in bovine cryptosporidiosis.

Antibody and cytokine response to Cystoisospora suis infections in immune-competent young pigs

Background

To date, investigations on the immune response to Cystoisospora suis infections focused on suckling piglets, the age group clinically most affected. Actively immunizing piglets is unfeasible due to their immature immune system and the typically early infection in the first days after birth. Therefore, understanding and possibly enhancing the immune response of immune-competent animals is the prerequisite to develop a passive immunization strategy for piglets which currently rely on very limited treatment options.

Methods

To investigate antibody and cytokine responses of immune-competent animals and the impact of the oral immunization protocol on their immune response, growers with unknown previous exposure to C. suis (10–11 weeks-old) were infected one or three times with different doses (600 and 6000 or 200 and 2000, respectively) of C. suis oocysts, and compared to uninfected controls. Oocyst excretion was evaluated, and blood and intestinal mucus antibody titers were determined by IFAT. Systemic production of Th1, Th2, inflammatory and regulatory cytokines was determined in different immune compartments at mRNA and (after stimulation with a recombinant merozoite-protein) at protein level by PCR and multiplex fluorescent immunoassay, respectively.

Results

Infection generated significantly increased serum IgA and IgG levels against C. suis sporozoites and merozoites, irrespective of infection mode, with IgG against merozoites showing the strongest increase. No clinical signs and only occasional excretion were observed. The systemic cytokine response to C. suis was only weak. Nonetheless, in white blood cells, IL-4, IL-6 and IL-10 mRNA-levels significantly increased after infection, whereas IFN-ɣ, IL-2 and TGF-β expression tended to decrease. In mesenteric lymph nodes (MLN), IL-10 and TNF-α levels were elevated while splenic cytokine expression was unaltered upon infection. Stimulated MLN-derived lymphocytes from infected pigs produced slightly more IL-12 and less IFN-α than controls.

Conclusions

An infection and a subsequent systemic immune response can be induced in immune-competent animals by all evaluated infection models and growers can be used as models to mimic sow immunizations. The immune response to C. suis, although mild and with considerable variation in cytokine expression, was characterized by a Th2-associated and regulatory cytokine profile and antibody production. However, none of the parameters clearly stood out as a potential marker associated with protection. Antibody titers were significantly positively related with oocyst excretion and might thus serve as correlates for parasite replication or severity of infection.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-2974-6) contains supplementary material, which is available to authorized users.

A clinically rare occurrence of rectal mucosal prolapse associated with tenesmus in a calf caused by Eimeria sp

Eimeria sp. is a host-specific intracellular parasite that mostly affects young animals. This parasite causes great economic losses in livestock sector. A 6 weeks old calf was brought to Referral Veterinary Polyclinic, ICAR-Indian Veterinary Research Institute, Izatnagar with the history of inappetance and passage of foul smelling diarrhoeic feces rich in occult blood and mucous for the last 3 days. On clinical examination, calf was found to be present in lateral recumbency and showed severe tenesmus, prolapsed rectal mucosa along with small quantity of blood mixed feces sticking to the perineum and tail regions. Diagnosis was done based on clinical observations and fecal examination which showed oocysts of Eimeria sp. The prolapsed rectal mucosa was corrected aseptically by manual procedure. The calf was treated with a combination of sulfadimidine and amprolium along with supportive therapy. The calf recovered clinically after 5 days of therapy and further fecal examination showed no evidence of oocysts of Eimeria sp.

OCORRÊNCIA DE EIMERIOSE EM BEZERROS CRIADOS EM PROPRIEDADES DE AGRICULTURA FAMILIAR - NOTA CIENTÍFICA

Resumo A ocorrência de eimeriose foi pesquisada em 110 bezerros da raça holandesa pertencentes a dez propriedades de agricultura familiar. As amostras de fezes foram coletadas via retal e analisadas por métodos parasitológicos qualitativos e quantitativos. Amostras de fezes positivas para Eimeria sp. foram submetidas à esporulação in vitro para posterior identificação microscópica da espécie. Todas as propriedades apresentaram positividade enteroparasitária por espécies do gênero Eimeria havendo uma prevalência de 48,2% dos animais parasitados. Foram identificadas oito espécies do gênero Eimeria, sendo E. Bovis, E. auburnensis e E. alabamensis as mais frequentes, com 23,6%, 11,8% e 9,1%, respectivamente. Animais com até seis meses de idade manejados de forma coletiva e a pasto apresentaram maior positividade enteroparasitária. A elevada prevalência de infecção parasitária em animais jovens, principalmente por coccidios de considerável patogenicidade, é indicador de falhas no manejo sanitário, sendo necessário criterioso monitoramento com uso de fármacos específicos para controlar infecções e reduzir perdas zootécnicas.

Far beyond Phagocytosis: Phagocyte-Derived Extracellular Traps Act Efficiently against Protozoan Parasites In Vitro and In Vivo

Professional mononuclear phagocytes such as polymorphonuclear neutrophils (PMN), monocytes, and macrophages are considered as the first line of defence against invasive pathogens. The formation of extracellular traps (ETs) by activated mononuclear phagocytes is meanwhile well accepted as an effector mechanism of the early host innate immune response acting against microbial infections. Recent investigations showed evidence that ETosis is a widely spread effector mechanism in vertebrates and invertebrates being utilized to entrap and kill bacteria, fungi, viruses, and protozoan parasites. ETs are released in response to intact protozoan parasites or to parasite-specific antigens in a controlled cell death process. Released ETs consist of nuclear DNA as backbone adorned with histones, antimicrobial peptides, and phagocyte-specific granular enzymes thereby producing a sticky extracellular matrix capable of entrapping and killing pathogens. This review summarizes recent data on protozoa-induced ETosis. Special attention will be given to molecular mechanisms of protozoa-induced ETosis and on its consequences for the parasites successful reproduction and life cycle accomplishment.

Eimeria bovis infection modulates endothelial host cell cholesterol metabolism for successful replication

During first merogony Eimeria bovis forms large macromeronts in endothelial host cells containing >120 000 merozoites I. During multiplication, large amounts of cholesterol are indispensable for the enormous offspring membrane production. Cholesterol auxotrophy was proven for other apicomplexan parasites. Consequently they scavenge cholesterol from their host cell apparently in a parasite-specific manner. We here analyzed the influence of E. bovis infection on endothelial host cell cholesterol metabolism and found considerable differences to other coccidian parasites. Overall, free cholesterol significantly accumulated in E. bovis infected host cells. Furthermore, a striking increase of lipid droplet formation was observed within immature macromeronts. Artificial host cell lipid droplet enrichment significantly improved E. bovis merozoite I production confirming the key role of lipid droplet contents for optimal parasite proliferation. The transcription of several genes being involved in both, cholesterol de novo biosynthesis and low density lipoprotein-(LDL) mediated uptake, was significantly up-regulated at a time in infected cells suggesting a simultaneous exploitation of these two cholesterol acquisition pathways. E. bovis scavenges LDL-derived cholesterol apparently through significantly increased levels of surface LDL receptor abundance and LDL binding to infected cells. Consequently, LDL supplementation significantly improved parasite replication. The up-regulation of the oxidized LDL receptor 1 furthermore identified this scavenger receptor as a key molecule in parasite-triggered LDL uptake. Moreover, cellular cholesterol processing was altered in infected cells as indicated by up-regulation of cholesterol-25-hydroxylase and sterol O-acyltransferase. Overall, these results show that E. bovis considerably exploits the host cell cholesterol metabolism to guarantee its massive intracellular growth and replication.

Dinâmica de eliminação de oocistos de Eimeria sp. durante a gestação e fase inicial da lactação em cabras nativas criadas extensivamente em região semiárida

<p>Objetivou-se com este estudo caracterizar a dinâmica de eliminação de oocistos de<italic>Eimeria</italic>sp<italic>.</italic> em cabras sem raça definida (SRD), criadas em sistema extensivo na região semiárida, durante a gestação e fase inicial da lactação. Vinte cabras adultas, criadas extensivamente na Caatinga, foram selecionadas e monitoradas durante oito meses. Os valores de Oopg (quantidade de oocistos por grama de fezes) foram acompanhados quinzenalmente do 1º mês de gestação ao 90º dia pós-parto. O Oopg variou durante a gestação, sendo as maiores e menores contagens de 3.300 ± 709 e 1.726 ± 215, respectivamente. Após elevação na primeira quinzena, o Oopg diminuiu gradualmente até o 105º dia e voltou a subir até o final da gestação. No período pós-parto, seguindo a tendência da fase final da gestação, houve aumento progressivo na eliminação de oocistos até o 90º dia de lactação. A quantidade média de oocistos liberados durante a fase inicial da lactação foi de 3.006 ± 102,3 Oopg comparado ao período gestacional de 2.312 ± 98,03 Oopg (P<0,05). A dinâmica de eliminação de oocistos de<italic>Eimeria</italic> sp. em cabras gestantes e lactantes, criadas extensivamente em região semiárida, foi caracterizada por três situações distintas: elevação brusca no início da gestação, seguida por redução gradual no período intermediário da gestação e aumento constante da eliminação de oocistos na fase final da gestação até inicial da lactação.</p>

The intriguing host innate immune response: novel anti-parasitic defence by neutrophil extracellular traps

The capacity of polymorphonuclear neutrophils (PMN) and other leucocytes of the innate immune system to expel their DNA in a controlled process into the extracellular environment to trap and kill pathogenic microorganisms led to a paradigm shift in our comprehension of host leucocyte-pathogen interactions. Formation of neutrophil extracellular traps (NETs) has recently been recognized as a novel effector mechanism of the host innate immune response against microbial infections. Meanwhile evidence has arisen that NET formation is a widely spread mechanism in vertebrates and invertebrates and extends not only to the entrapment of microbes, fungi and viruses but also to the capture of protozoan and metazoan parasites. PMN produce NETs after stimulation with mitogens, cytokines or pathogens in a controlled process which depends on reactive oxygen species (ROS) and the induction of the Raf-MEK-ERK-mediated signalling pathway cascade. NETs consist of nuclear DNA as a backbone decorated with histones, antimicrobial peptides, and PMN-specific granular enzymes thereby providing an extracellular matrix capable of entrapping and killing invasive pathogens. This review is intended to summarize parasite-related data on NETs. Special attention will be given to NET-associated mechanisms by which parasites, in particular apicomplexa, might be hampered in their ability to reproduce within the host cell and complete the life cycle.

Immunization with Eimeria ninakohlyakimovae-live attenuated oocysts protect goat kids from clinical coccidiosis

Caprine coccidiosis, affecting mainly young goat kids around the weaning period, is worldwide the most important disease in the goat industry. Control of caprine coccidiosis is increasingly hampered by resistances developed against coccidiostatic drugs leading to an enhanced need for anticoccidial vaccines. In the current study we conducted an oral immunization trial with live attenuated sporulated Eimeria ninakohlyakimovae oocysts. Sporulated E. ninakohlyakimovae oocysts were attenuated by X-irradiation technique. The experimental design included a total of 18 goat kids divided into the following groups: (i) animals immunized with attenuated E. ninakohlyakimovae oocysts at 5 weeks of age and challenged 3 weeks later with non-irradiated homologous oocysts (group 1); (ii) animals infected with non-attenuated E. ninakohlyakimovae oocysts at 5 weeks of age and challenged 3 weeks later with non-attenuated homologous oocysts (group 2); (iii) animals primary-infected with untreated E. ninakohlyakimovae oocysts at 8 weeks of age (control of the challenge infection, group 3); (iv) non-infected control animals (group 4). Goat kids immunized with live attenuated E. ninakohlyakimovae oocysts (group 1) excreted significantly less oocysts in the faeces (95.3% reduction) than kids infected with non-attenuated ones (group 2). Furthermore, immunization with live but attenuated oocysts resulted in ameliorated clinical coccidiosis compared to goat kids infected with untreated oocysts (group 2) and resulted in equally reduced signs of coccidiosis after challenge infection compared to acquired immunity driven by non-attenuated oocysts. Overall, the present study demonstrates for the first time that live attenuated E. ninakohlyakimovae oocysts orally administered showed almost no pathogenicity but enough immunogenicity in terms of immunoprotection. Importantly, vaccinated animals still shed low amounts of oocysts, guaranteeing environmental contamination and consecutive booster infections to sustain ongoing immunity.

Hematological and serum biochemical analyses in experimental caprine coccidiosis

In order to provide information on hematological and biochemical changes in Eimeria arloingi infection, eighteen newborn kids were allocated to three equal groups. Two groups, A and B were inoculated with a single dose of 1 × 10(3) and 1 × 10(5) sporulated oocysts of E. arloingi, respectively. The third group C remained uninfected as control. Blood samples were collected from jugular vein before inoculation as control and at 7, 14, 21, 28, 35 and 42 days post inoculation (DPI). Total erythrocyte and total leukocyte counts, hemoglobin (Hb), packed cell volume (PCV) and differential leukocyte counts were determined. Serum biochemical parameters including total protein (TP), albumin, chloride (Cl(-)), sodium (Na(+)), potassium (K(+)), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and gamma glutamyltransferase (GGT) were measured. All infected animals showed symptoms of clinical coccidiosis including diarrhea and oocyst excretion after the prepatent period that varied from 16 to 18 days after inoculation. The oocysts output did not stop until the end of the experiment. The diarrhea was associated with a reduction in ALP activity, increases in PCV and Hb and decreases in Na(+), Cl(-) and K(+). No significant differences were found in AST, ALT, GGT, albumin and TP during 42 DPI. There was no hepatic damage.

Frequency of species of Eimeria in females of the holstein-friesian breed at the post-weaning stage during autumn and winter

The frequency of species of the genus Eimeria in a dairy herd in the municipality of Boa Esperança, Southern region of the State of Minas Gerais was assessed. From 37 females of the Friesian breed aged three to seven months, 259 feces samples were analyzed between May and September 2008. The examinations to quantify oocysts per gram of feces (OPG) and identify Eimeria species were conducted at the Veterinary Parasitology Laboratory of the Federal University of Lavras. Eleven species of Eimeria were identified, namely: E. bovis (23.2%), E. zuernii (22.6%), E. ellipsoidalis (20.3%), E. cylindrica (14.1%), E. subspherica (5.4%), E. canadensis (3.5%), E. alabamensis (2.4%), E. auburnensis (2.4%), E. pellita (2.1%), E. brasiliensis (2%) and E. bukidnonensis (1.9%). E. bovis, E. zuernii and E. ellipsoidalis were the most frequent and the ones with the highest oocyst shedding over time (p < 0.05). Differences in OPG counts were found between most months studied (p < 0.05). The large number of Eimeria species found, in particular E. bovis and E. zuernii, indicates that Eimeria sp. has significant pathogenic potential in dairy cattle in the South of Minas Gerais.

Prevalence of Eimeria bovis and Eimeria zuernii in German cattle herds and factors influencing oocyst excretion

The present study was designed to investigate the prevalence of the pathogenic coccidia species E. bovis and E. zuernii in shed-reared animals in German dairy and fattening facilities.Samples were obtained from 65 cattle farms distributed randomly across all the regions of Germany, regardless of the occurrence of clinical problems. The samples were obtained rectally. Faecal consistency and the total number of oocysts per gram of faeces (OPG) were determined for Eimeria spp., along with the separate OPG values for Eimeria (E.) bovis and E. zuernii. A questionnaire was completed for each farm to record information about herd size and management together with individual animal data. Eimeria oocysts, regardless of the kind of Eimeria spp., were detected in 62 of these farms, which gives a prevalence of 95.4 %. The farm prevalence of the pathogenic species was 76.9 % for E. bovis and 83.1 % for E. zuernii. The average oocyst excretion level was 2,950 OPG in terms of total Eimeria spp. oocyst excretion, 700 OPG for E. bovis and 1,500 OPG for E. zuernii.The number of oocysts excreted could not be correlated significantly with farm type or farm management but depended on the floor type which influences the infection pressure, on the age of the calves and the time after rehousing. In general, higher oocyst excretion rates were found in calves kept on litter compared to rearing on slatted floor. Younger calves and calves sampled early after housing shed higher amounts of oocysts than older calves and calves stabled a longer period before sampling, respectively. Furthermore, there was a positive correlation between OPG and the observation of diarrhoea, defined as observation of a loose to liquid faecal consistency. Excretion of E. zuernii oocysts was more closely linked to the occurrence of diarrhoea than E. bovis oocyst excretion. This study confirms that the pathogenic coccidia E. bovis and E. zuernii are ubiquitous in German cattle populations and a significant cause of diarrhoeal disease in calf rearing.

Genetic analysis and development of species-specific PCR assays based on ITS-1 region of rRNA in bovine Eimeria parasites

At present, morphological characteristics of oocyst is the only achievable method for the identification of bovine coccidia to the species level. In this study, the internal transcribed spacer 1 (ITS-1) region of ribosomal RNA genes of six bovine Eimeria species; E. alabamensis, E. auburnensis, E. bovis, E. cylindrica, E. ellipsoidalis and E. zuernii, were sequenced and analyzed the phylogenetic relationship among them. In pair-wise alignment, the sequences among the same species had high homology of over 90%. E. bovis and E. zuernii were closely related within the same cluster. This cluster and E. alabamensis were distant from major cluster of bovine coccidia that included E. auburnensis, E. cylindrica and E. ellipsoidalis. Species-specific PCR assays based on the amplification of the ITS-1 region were also developed to identify the 6 pathogens. The ITS-1 region of each Eimeria species had sufficient inter-specific sequence variation enough to design the primer sets that differentially amplified each target species. This PCR assay for the detection and differentiation of Eimeria parasite showed higher sensitivity when compared to the conventional oocyst-morphological examination. This is the first attempt for the identification of 6 bovine Eimeria parasites in the genomic level and may provide as useful methods for diagnosis and epidemiology of bovine coccidial infection.

Influence of experimental Eimeria zuernii infection on clinical blood chemistry in calves

Coccidiosis, often caused by Eimeria zuernii infection, is an important diarrhoeal disease in calves [Fitzgerald, P.R., 1980. The economic impact of coccidiosis in domestic animals. Adv. Vet. Sci. Comp. Med. 24, 121-143]. Infection trials were performed to investigate the effects of experimental E. zuernii coccidiosis on clinical blood chemistry in calves. Three groups of calves were formed: group 1 (n=14) served as uninfected control group, group 2 (n=11) was infected with 150,000 sporulated E. zuernii oocysts per calf, and group 3 (n=16) was infected with 250,000 sporulated E. zuernii oocysts per calf. Measurements throughout the prepatent and the patent period revealed a marked influence of E. zuernii infection on the following parameters: total protein, albumin, urea, bilirubin, creatine kinase, free fatty acid concentration, and cholesterol. Aberrances in these were most pronounced in group 3. No significant and/or distinct changes after infection could be detected in blood glucose concentration. E. zuernii infection impairs intestinal function and induces catabolic metabolism in affected calves. Bilirubin, urea and cholesterol concentration, and creatine kinase activity were particularly affected indicating catabolism of protein and lipids.