Endoparasites in calves of beef cattle herds: management systems dependent and genetic influences

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.

Giardia duodenalis Styles, 1902 Prevalence in Cattle (Bos taurus Linnaeus, 1758) in Europe: A Systematic Review

Giardia duodenalis Styles, 1902 is an infectious agent which can cause enteritic disease in cattle (Bos taurus Linnaeus, 1758) worldwide. As a zoonotic protozoan, it is important to acknowledge Giardia prevalence and assemblages found in cattle and risk factors associated with the Giardia infection in herds. This systematic review aims to estimate the prevalence of G. duodenalis and its assemblages in cattle and to identify the risk factors associated with Giardia infection in cattle in Europe. A systematic review was performed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines to collect information from published studies in Europe. A total of 1414 studies were identified and 17 relevant studies were included in this review. Mean Giardia prevalence in cattle in Europe was 35.1%, with the highest prevalence found in neonatal animals (39.6%), but mean heard prevalence was 67.0%. Mixed infections of Giardia assemblages A and E were found most frequently (55.6%), while assemblages A and B were found more frequently in animals under 24 months old. Risk factors, such as deep litter with run-out, prolonged calf contact with the dam, and seasonality, such as winter and spring, were found to be potential risk factors for Giardia presence in the herds.

Occurrence and biodiversity of Eimeria spp. (Apicomplexa: Eimeriidae) in Madura cattle reared on Kamal Subdistrict, Madura Island, Indonesia

Background and Aim:

In Indonesia, Madura cattle are native breeds that are expected to contribute to the improvement of regional meat self-sufficiency. Eimeria spp. are protozoans that are commonly found in ruminants. This study aimed to identify the occurrence and diversity of Eimeria spp. in Madura cattle.

Materials and Methods:

In this study, fresh fecal samples were collected from 100 cattle in Kamal Subdistrict, Bangkalan District, Madura Island, Indonesia. Morphological detection was performed using a light microscope, and molecular identification was performed using a polymerase chain reaction. DNA amplification was conducted using various species-specific primers for Eimeria bovis, Eimeria zuernii, Eimeria auburnensis, Eimeria alabamensis, Eimeria ellipsoidalis, and Eimeria cylindrica.

Results:

The results obtained 21% (21/100) of Eimeria spp. based on morphological detection. A total of 15 positive samples with 500–25,000/mL oocysts were selected for DNA extraction and amplification, resulting in 12 positive samples. Four Eimeria spp. were obtained based on molecular identification: E. bovis, E. zuernii, E. auburnensis, and E. cylindrica.

Conclusion:

Four species of Eimeria namely E. bovis, E. zuernii, E. auburnensis, and E. cylindrica were identified from fecal sample of Madura cattle using PCR method in this study. Further comprehensive studies are required to investigate the pathogenicity of Eimeria spp. in Madura cattle. Therefore, improved and integrated management practices should be strengthened by local governments to prevent pathogenic diseases and increase national livestock productivity in Indonesia.

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.

Pasture rewetting in the context of nature conservation shows no long-term impact on endoparasite infections in sheep and cattle

BACKGROUND

Nature conservation with reduced drainage of pastures has been increasingly promoted in agriculture in recent years. However, moisture on pastures is a crucial factor for the development of free-living stages of many parasite species in ruminants. Hence, for the first time, we conducted a field study between 2015 and 2017 at the German North Sea coast to investigate the long-term effect of pasture rewetting (since 2004) on endoparasite infections in sheep and cattle.

METHODS

We examined faecal samples of 474 sheep and 646 cattle from five farms in spring, summer and autumn each year for the presence of endoparasite infections. Animals were kept on conventionally drained, undrained and rewetted pastures. The association between pasture rewetting and endoparasite infection probability was analysed in generalized linear mixed models and including further potential confounders.

RESULTS

Infection frequencies for gastrointestinal strongyles, Eimeria spp. and Strongyloides papillosus were significantly higher in sheep (62.9%, 31.7% and 16.7%) than in cattle (39.0%, 19.7% and 2.6%). Fasciola hepatica was detected with a frequency of 13.3% in sheep and 9.8% in cattle, while rumen fluke frequency was significantly higher in cattle (12.7%) than in sheep (3.8%). Nematodirus spp., lungworms (protostrongylids, Dictyocaulus viviparus), Moniezia spp., Trichuris spp. and Dicrocoelium dendriticum were identified in less than 7% of samples. Co-infection with more than three endoparasite taxa was present significantly more often in sheep than in cattle. We identified significant positive correlations above 0.2 for excretion intensities between S. papillosus with strongyles, Eimeria spp. and Nematodirus spp. in sheep and between strongyles and Nematodirus spp. in cattle. Pasture rewetting had no long-term effect on endoparasite infections, neither in sheep nor in cattle. Interestingly, F. hepatica infections decreased significantly in sheep and cattle from 2015 (10.9% and 13.9%) to 2017 (1.4% and 2.1%).

CONCLUSIONS

Pasture rewetting for nature conservation did not increase endoparasite infection probability in ruminants in the long term. This finding should be confirmed in ongoing studies aimed at further animal welfare parameters. The rapid decrease in F. hepatica infections over 3 years may suggest climatic impact or competition with rumen flukes in addition to potential anthelmintic treatment after feedback of the results to the farmers.

Literature Review: Coinfection in Young Ruminant Livestock-Cryptosporidium spp. and Its Companions

The protozoan Cryptosporidium parvum is one of the major causative pathogens of diarrhoea in young ruminants; therefore, it causes economic losses and impairs animal welfare. Besides C. parvum, there are many other non-infectious and infectious factors, such as rotavirus, Escherichia coli, and Giardia duodenalis, which may lead to diarrhoeic disease in young livestock. Often, more than one infectious agent is detected in affected animals. Little is known about the interactions bet-ween simultaneously occurring pathogens and their potential effects on the course of disease. In this review, a brief overview about pathogens associated with diarrhoea in young ruminants is presented. Furthermore, information about coinfections involving Cryptosporidium is provided.

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.

Welfare Assessment in Calves Fattened According to the "Outdoor Veal Calf" Concept and in Conventional Veal Fattening Operations in Switzerland

Simple Summary

Antimicrobial use in humans and animals leads to the selection of resistant bacteria, a serious threat to human and animal health, as such bacteria can lead to treatment failure and death. With the “outdoor veal calf” concept, a novel calf fattening system was developed that allows for reducing antimicrobial use by 80% through improvements in management and housing, such as health check before purchase, short transport, vaccination, quarantine in individual hutches, and fattening in small groups in a roofed, straw-bedded paddock with a group hutch for shelter. In that system, veal calves spend their entire lives outdoors in the fresh air. In our study, we wanted to make sure that the observed reduction in antimicrobial treatments was not achieved at the cost of animal welfare, i.e., that sick animals were not left without treatment in order to obtain better figures for treatment reduction. Our results show that calves in the “outdoor veal calf” system had fewer signs of respiratory and digestive diseases than control calves and that their lungs had fewer lesions of pneumonia than controls after slaughter. Thus, not only was antimicrobial use drastically reduced, but calf health was really improved in the new “outdoor veal calf” system.

Abstract

The “outdoor veal calf” system was developed to encounter the demand for a veal fattening system that allows for reducing antimicrobial use without impairing animal welfare. Management improvements including direct purchase, short transportation, vaccination, three-week quarantine in individual hutches, and open-air housing in small groups in a roofed, straw-bedded paddock with a group hutch were implemented in a prospective intervention study (1905 calves, 19 intervention and 19 control farms, over one year): antimicrobial use was five times lower in "outdoor veal" farms compared to control farms (p < 0.001), but it was crucial to ensure that antimicrobial treatment reduction was not associated with decreased animal welfare, i.e., that sick animals were not left untreated. Welfare was assessed monthly on the farms, and organs of 339 calves were examined after slaughter. Cough and nasal discharge were observed significantly (p ≤ 0.05) less often in intervention than in control farms, mortality (3.1% vs. 6.3%, p = 0.020) and lung lesion prevalence (26% vs. 46%, p < 0.001) were lower; no group difference was seen in abomasal lesion prevalence (65% vs. 72%). Thus, besides reduced antimicrobial use, calf health and welfare were improved in "outdoor veal calf" farms in comparison to traditional operations.

Gastro-intestinal parasite infections of Ankole cattle in an unhealthy landscape: An assessment of ecological predictors

The distribution of gastro-intestinal (GI) parasites across landscapes is closely related to the spatial distribution of hosts. In GI parasites with environmental life stages, the vitality of parasites is also affected by ecological and landscape-related components of the environment. This is particularly relevant for domestic livestock species that are often kept across habitats with varying degrees of degradation, exposing them to a wide range of environmentally robust parasite species. In our study, we examined the effect of environmental and anthropogenic factors on the prevalence and intensity of GI parasites across a free-ranging stock of Ankole cattle in the Mutara rangelands of northeastern Rwanda. Prevalence and intensity of each parasite type (i.e., strongyle-type nematodes, Strongyloides spp., Moniezia spp., and Eimeria spp.) were used as dependent variables. Two fixed factors related to season and conservation-political history, together with three principal components (condensed from nine ecological variables) were used as independent covariates in a univariate General Linear Model (GLM). Major effects on the prevalence and intensity of strongyle-type nematodes and on the intensity of Eimeria spp. were found in that vegetation-related effects such as above-ground grass biomass in conjunction with a high degree of soil compaction had a negative relationship with these parasite types. These unexpected findings suggest that strongyle-type and coccidian infections increase with increasing rangeland degradation. Strongyle-type nematode prevalence and intensity were also negatively related to goat/sheep density, indicating a 'dilution effect' of GI infections between domestic livestock species.

Duplications and Positive Selection Drive the Evolution of Parasitism-Associated Gene Families in the Nematode Strongyloides papillosus

Gene duplication is a major mechanism playing a role in the evolution of phenotypic complexity and in the generation of novel traits. By comparing parasitic and nonparasitic nematodes, a recent study found that the evolution of parasitism in Strongyloididae is associated with a large expansion in the Astacin and CAP gene families.To gain novel insights into the developmental processes in the sheep parasite Strongyloides papillosus, we sequenced transcriptomes of different developmental stages and sexes. Overall, we found that the majority of genes are developmentally regulated and have one-to-one orthologs in the diverged S. ratti genome. Together with the finding of similar expression profiles between S. papillosus and S. ratti, these results indicate a strong evolutionary constraint acting against change at sequence and expression levels. However, the comparison between parasitic and free-living females demonstrates a quite divergent pattern that is mostly due to the previously mentioned expansion in the Astacin and CAP gene families. More detailed phylogenetic analysis of both gene families shows that most members date back to single expansion events early in the Strongyloides lineage and have undergone subfunctionalization resulting in clusters that are highly expressed either in infective larvae or in parasitic females. Finally, we found increased evidence for positive selection in both gene families relative to the genome-wide expectation.In summary, our study reveals first insights into the developmental transcriptomes of S. papillosus and provides a detailed analysis of sequence and expression evolution in parasitism-associated gene families.

Patent gastrointestinal nematode infections in organically and conventionally pastured dairy cows and their impact on individual milk and fertility parameters

Infections with gastrointestinal nematodes (GIN) can lead to production losses and impacts on product quality in affected cows, which has mainly been demonstrated during deworming experiments or via herd-level measurements. Here, a field study was carried out to explore the association between GIN infection status and milk production as well as fertility parameters in individual dairy cows. Different selection lines of Black and White cows were included in the study, which were distributed among 17 small and medium-sized organic and conventional German grassland farms. Faecal samples of 1166 dairy cows were examined twice, in July and September 2015. Nematode eggs were found in the faeces of 473 (40.6%) cows. As expected, strongylid eggs (Trichostrongylidae or Oesophagostomum and Bunostomum spp., respectively) were the predominant morphotype, followed by Strongyloides papillosus and Capillaria spp. eggs. In July, cows kept under organic conditions had a significantly lower GIN prevalence in comparison to cows kept on conventional farms. Faecal egg counts were generally low, with the highest value in September and an arithmetic mean of 11.3 eggs per gram faeces (EPG) for all observations. The relationships between GIN infection status and milk yield (kg milk/cow/day), milk protein content (%) and milk fat content (%) for each first test-day record after parasitological assessment were estimated by using linear mixed models. Milk protein content was estimated 0.05% lower in GIN positive compared to GIN negative cows, whereas no significant effect on milk yield or milk fat content was observed. The impact of GIN infection status on success in first insemination (SFI) was estimated by using a threshold model. No significant association was demonstrated between GIN infection status and SFI. Unexpectedly, the fertility parameter days from calving-to-first-service (CTFS) showed a significantly shorter average interval in GIN positive cows. However, these data on reproductive performance need to be considered preliminary as long-term studies are needed to allow a firm prediction of the impact of GIN infection status on dairy cow fertility parameters.

Prevalence of Cryptosporidium spp. in calves under one year old in Ilam county (Iran), from March 2014 to February 2015

Introduction

Cryptosporidium is a coccidian parasite that can infect most mammals, including humans. This parasite is an important cause of neonatal diarrhea and morbidity in calves, causing substantial economic loss to animal husbandry. Because of the importance of this parasite in calves, this study was designed in order to determine prevalence of Cryptosporidium spp. among calves under one year old in Ilam county (Iran).

Methods

Prevalence of Cryptosporidium spp. was estimated using a cross-sectional study. Fecal samples from 400 calves under 1 year old were collected in Ilam County, from March 2014 to February 2015 and they were microscopically analyzed using modified Ziehl-Neelsen method (mZN).

Results

The overall prevalence of Cryptosporidiosis in calves was 16% (64/400). According to age categories, the highest infection was observed in calves under one month old, and the lowest infection occurred in calves 6 to 12 months old. Age was significantly associated with Cryptosporidium spp. infection (p<0.05). The prevalence of Cryptosporidiosis in diarrheic and none diarrheic calves was 27.3 and 12.4 % respectively, which indicated a significant association between positivity and diarrhea (p<0.05). The highest prevalence was observed in winter followed by autumn, spring and summer respectively. No statically difference was found between prevalence of Cryptosporidiosis and seasons of sampling. Also, calves’ gender was not associated with Cryptosporidium spp. infection in this study.

Conclusion

Our results provide useful information about the distribution of Cryptosporidium spp. Also, the role of potential risk factors including age, sex, clinical status and seasons of sampling was indicated in studied calves from Ilam County.

Fecal parasite identification by microscopy and PCR in scimitar-horned oryx, Oryx dammah, managed at two sites

The scimitar-horned oryx, Oryx dammah, an endangered species extinct in the wild, is managed in various captive management programs and is the focus of reintroduction efforts. Management variability can contribute to substantial parasite load differences, which can affect deworming programs and potentially transfer parasites to different regions with translocations. Parasite studies in O. dammah are lacking. In this study, we determined fecal egg/oocyst counts of O. dammah in two captive herds, Fossil Rim Wildlife Center (FRWC) and Kansas City Zoo (KCZ). Fecal egg counts (FEC) were performed on O. dammah feces collected seasonally using the modified McMaster method, and microscopy provided additional identification of parasite genera ova and oocysts. To identify parasites to species level, homogenized fecals provided DNA subjected to the polymerase chain reaction (PCR) using genus specific primers. Microscopy and sequencing results indicated the presence of Strongylus (Strongylus vulgaris, Angiostrongylus cantonensis), Trichostrongylus (Haemonchus contortus, Camelostrongylus mentulatus), Trichuris (T. leporis, T. ovis, and T. discolor), Isospora (Isospora gryphoni) and Eimeria (E. zuernii and E. bovis), with Strongylus being the most common. Nematodirus was identified through microscopy at FRWC. Fecal egg counts were significantly higher in (FRWC) than in (KCZ) in all samplings (P = <0.001). No significant difference was seen between parasite load and seasons (P = 0.103), nor site and season (P = 0.51). Both study sites maintained most animals within commonly accepted FEC levels found in domestic livestock. Individuals with high numbers of EPG or OPG were subordinate males, pregnant females, or neonates. Several significant interactions were found between genera of parasites, age, sex, season, and pregnancy status in the FRWC herd. Sampling limitations prevented further analysis of the KCZ herd. Understanding interactions between parasite loads and physiological, environmental, and regional differences can help determine inter-specific transfer of parasites, and establish appropriate anthelmintic programs for O. dammah herds.

Strongyloides spp. infections of veterinary importance

This paper reviews the occurrence and impact of threadworms, Strongyloides spp., in companion animals and large livestock, the potential zoonotic implications and future research. Strongyloides spp. infect a range of domestic animal species worldwide and clinical disease is most often encountered in young animals. Dogs are infected with Strongyloides stercoralis while cats are infected with different species according to geographical location (Strongyloides felis, Strongyloides tumefaciens, Strongyloides planiceps and perhaps S. stercoralis). In contrast to the other species, lactogenic transmission is not a primary means of infection in dogs, and S. stercoralis is the only species considered zoonotic. Strongyloides papillosus in calves has been linked to heavy fatalities under conditions of high stocking density. Strongyloides westeri and Strongyloides ransomi of horses and pigs, respectively, cause only sporadic clinical disease. In conclusion, these infections are generally of low relative importance in livestock and equines, most likely due to extensive use of macrocyclic lactone anthelmintics and/or improved hygiene. Future prevalence studies need to include molecular typing of Strongyloides species in relation to different hosts. More research is urgently needed on the potential zoonotic capacity of Strongyloides from dogs and cats based on molecular typing, information on risk factors and mapping of transmission routes.

Comparative efficacy of diclazuril (Vecoxan®) and toltrazuril (Baycox bovis®) against natural infections of Eimeria bovis and Eimeria zuernii in French calves

A blinded, randomized, controlled, multi-centric field study was conducted on French dairy farms (n = 9) to evaluate the long term efficacy of metaphylactic, single oral treatments with either 1 mg/kg body weight (BW) of diclazuril (Vecoxan®), or 15 mg/kg BW of toltrazuril (Baycox®) against natural infections with Eimeria zuernii and/or Eimeria bovis, compared to untreated control animals. A total of 199 calves from nine commercial farms aged between 21 and 55 days old at the start of study were included and randomly allocated to one of three groups. Calves on all farms were observed for a period of 78 days post treatment, using both parasitological (oocyst excretion), and clinical parameters (faecal score and body weight). The assessment of efficacy was based on both control of oocyst excretion, and on the average daily weight gains throughout the study. During the whole study period, the mean number of days with diarrhoea (≥ 2) was similar (0.7 days) between treated groups. Excretion in the untreated group peaked at 21 days after treatment. In both the diclazuril and toltrazuril-treated groups, mean oocyst excretion decreased dramatically in the five days following treatment. Thereafter, particularly towards the end of the study period, oocyst counts and percentage levels of E. zuernii were highest in the toltrazuril-treated group. In pooled data from all trial sites, the average daily weight gain was significantly (p = 0.01) higher (+ 0.057 kg/day) in the diclazuril group when compared to the toltrazuril group, and the average body weight gain of the diclazuril treated group was 4.4 kg higher than the toltrazuril group. On eight of the nine trial sites, the average daily gain was greater in the diclazuril group than in the toltrazuril group. This study demonstrates that, over an extended observation period of 78 days, metaphylactic treatment with both diclazuril and toltrazuril reduces the impact of coccidiosis, but greater performance benefits based on average daily weight gains, were achieved following the use of diclazuril.

Giardiosis and other enteropathogenic infections: a study on diarrhoeic calves in Southern Germany

BACKGROUND

Diarrhoea induces massive problems in the rearing of calves. The aim of the study was to obtain current data about the frequency of Giardia spp., Cryptosporidium spp. and Eimeria spp. in diarrhoeic calves in Southern Germany with the particular focus on giardiosis.

RESULTS

1564 samples were analysed for the three pathogens using microscopical methods. Giardia spp. was detectable in 112/1564 samples (7.2%). The mean age was 46.5 days and the odds of being infected with Giardia spp. increased slowly up to 8 times from about 12 days to 30 days of age. There appeared to be no seasonal influence on the frequency of Giardia spp. A mono-infection with Giardia spp. was diagnosed in 46 calves (2.9%) whereas 15 calves (1.0%) had a mixed-infection with Cryptosporidium spp. and 51 calves (3.3%) with Eimeria spp. Cryptosporidium spp. and Eimeria spp. could be detected in 646/1564 samples (41.3%) and 208/1564 samples (13.3%), respectively, with a mean age of 11.3 and 55.0 days, respectively. The odds of being infected with Cryptosporidium spp. increased up to 4.5 times until an age of 10 days. After that the odds decreased continuously and was approaching zero at about 30 days. The odds of being infected with Eimeria spp. increased continuously up to 30 times from about 20 days to 60 days of age. There appeared to be no significant seasonal influence on the frequency of Cryptosporidium spp.; but there was one for Eimeria spp.: the odds of being infected with Eimeria spp. in March and April decreased by about half and increased up to 2.3 times between July and September. Additionally, as requested by the veterinarians, 1282 of those samples were analysed for E. coli, Rota-, Coronavirus and Cryptosporidium spp. using an ELISA. Obtained frequencies for these pathogens were 0.9%, 37.8%, 3.4% and 45.3% with a mean age of 24.8 days, 12.1 days, 9.0 days and 12.1 days, respectively.

CONCLUSIONS

The results indicate that in Southern Germany in addition to Eimeria spp., Giardia spp. seems to play a contributing role in diarrhoea in older calves, whereas Cryptosporidium spp. and Rotavirus are mostly relevant in young calves.

Prevalence of coccidial infection in dairy cattle in Shanghai, China

The prevalence of coccidial infections in dairy cattle was examined in Shanghai from November 2010 to March 2011. In total, 626 fecal samples from 24 dairy farms were examined; oocysts were identified to the species level based on morphological features. All herds were infected with Eimeria species. The overall prevalence of coccidia was 47.1%, with the highest prevalence in <4-mo-old calves (51.8%) and the lowest in >12-mo-old cattle (27.0%). The number of oocysts per gram of feces was significantly higher in young calves than in weaners and adults. Ten species of Eimeria were identified, among which Eimeria ellipsoidalis, Eimeria bovis, Eimeria zuernii, and Eimeria alabamensis were the predominant species. Concurrent infection with 2-8 species was common.

Prevalence of Eimeria infection in yaks on the Qinghai-Tibet Plateau of China

Few data are available on the prevalence of Eimeria spp. in yaks. An observational study was conducted to determine the prevalence of coccidial infection in yaks on the Qinghai-Tibet Plateau of China. A total of 324 fecal samples from 4 counties was examined, and oocysts were identified to the species level on the basis of morphological features. Eimeria oocysts were found in 113 (34.9%) samples. The species detected and their prevalence values included the following: Eimeria zuernii (54.9%), E. pellita (35.4%), E. canadensis (33.6%), E. bovis (23.0%), E. cylindrica (16.8%), E. subspherica (16.8%), E. ellipsoidalis (14.1%), E. brasiliensis (13.3%), E. wyomingensis (8.0%), E. alabamensis (7.1%), E. illinoisensis (5.3%), E. auburnensis (4.4%), E. bombayansis (3.5%), and E. bukidnonensis (2.7%). Mixed infections of 2 to 7 species were found in 66.4% of the animals. There was an age-related difference in the prevalence of infection. The highest prevalence (53.3%) was observed in calves, an intermediate prevalence in yearlings (36.1%), and the lowest was in adults (15.6%). The number of oocysts per g of feces was significantly higher in calves than in adults. More Eimeria species were indentified in calves. Eimeria zuernii was the most prevalent species in calves and adults, whereas in yearling yaks E. pellita was most common. The majority of calves and yearlings showed mixed infection, but adults tended to be infected with 1 species. The prevalence and intensity of Eimeria species were found to show statistically significant differences among different regions in Qinghai Province.

Strongyloides papillosus: changes in transcript levels of lysozyme and aspartic protease 2 in percutaneously migrated larvae

The infection of the host is the crucial event in the life-cycle of parasites. To understand the molecular mechanisms of this important step, different methods are used in present studies. For analysis of changes in transcript levels the most sensitive method is the quantitative real-time PCR (qPCR). For an accurate analysis the evaluation of a set of adequate reference genes is necessary. The present study aimed to analyse the transcriptional levels of two genes of interest, the putative aspartic protease Spa-asp-2 and the putative lysozyme Spa-lys, in infective, free-living larvae of Strongyloides papillosus at different ages and from long-term and short-term infections and percutaneously migrated ("parasitic") larvae. Percutaneously migrated larvae were collected using the PERL chamber system and ovine skin in vitro. Reference genes identified as most suitable for transcriptional analysis according to geNorm analysis were genes for the eukaryotic translation elongation factor 1 alpha (Spa-eft-2), actin variation 2 (Spa-act-v2) and beta tubulin (Spa-tbb-1). Transcriptional analysis of the genes in percutaneously migrated larvae showed an upregulation of Spa-asp-2, while Spa-lys was downregulated. Data from the presented study provide a first glance into the changes of transcript levels of S. papillosus induced by percutaneous migration.

Bovine Eimeria species in Austria

Bovine eimeriosis is considered to be of considerable importance for the productivity and health of cattle worldwide. Despite the importance of cattle farming in Austria, little is known in this country about the abundance and distribution of bovine Eimeria spp. The objective of this study was to obtain detailed information about the occurrence of different Eimeria spp. on Austrian dairy farms. Fecal samples from individual calves (n = 868) from 296 farms all over Austria (82 districts) were collected. Additionally, each farmer was questioned about the occurrence of calf diarrhea, and about the knowledge on coccidiosis and possible control measures. On 97.97% of the investigated farms, calves excreted Eimeria oocysts, and 83.67% of the individual samples were positive. After sporulation of positive samples pooled from each farm, 11 Eimeria species were found, with E. bovis (in 65.54% of the samples and 27.74% of the farms), E.zuernii (63.85%/13.86%), E. auburnensis (56.76%/13.41%) and E. ellipsoidalis (54.05%/14.38%) being the most prevalent, followed by E. alabamensis (45.61%/11.56%), E. subspherica (35.14%/5.5.05%), E. cylindrica (33.11%/7.00%), and E. canadensis (31.08%/7.74%). E. wyomingensis, E. pellita and E. bukidnonensis were only found sporadically (3.04–4.73% of the samples and 0.16–0.59% of the farms). Mixed infections were present on all farms (2–9 Eimeria species/farm). Prevalences by state provinces were high throughout with 77.1–87.9% of the samples and 93.8–100% of the farms. Lower Austria had the highest percentage of positive farms, and Vorarlberg the lowest. Individual OPG (oocysts per gram of feces) values were generally low; 75% of the samples had an OPG of 1,000 or less. The highest detected OPG was 72,400. The mean OPG was 2,525 with above average numbers in Tirol, Carinthia, and Lower Austria. The mean OPG values were significantly positively correlated with the cattle density in the different districts. The majority of the samples were from female Simmenthal calves. Clinical coccidiosis (diarrhea) was observed in 74 cases, and (semi-)liquid diarrhea (56 animals) was significantly correlated with OPG (p < 0.05). Linear regression on the OPG data showed that OPG values significantly decreased with increasing age of the calves, while the percentage of positive samples increased with age (p < 0.05 for both). The term “coccidia” was familiar to 45% of the farmers, and anticoccidial treatment was performed by 13.51% of them, most commonly with toltrazuril. Considering the ubiquitous occurrence and the possible clinical and economic relevance of calf eimeriosis, infections should receive increased attention by both farmers and veterinarians.

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.

Zoonotic potential and molecular epidemiology of Giardia species and giardiasis

Molecular diagnostic tools have been used recently in assessing the taxonomy, zoonotic potential, and transmission of Giardia species and giardiasis in humans and animals. The results of these studies have firmly established giardiasis as a zoonotic disease, although host adaptation at the genotype and subtype levels has reduced the likelihood of zoonotic transmission. These studies have also identified variations in the distribution of Giardia duodenalis genotypes among geographic areas and between domestic and wild ruminants and differences in clinical manifestations and outbreak potentials of assemblages A and B. Nevertheless, our efforts in characterizing the molecular epidemiology of giardiasis and the roles of various animals in the transmission of human giardiasis are compromised by the lack of case-control and longitudinal cohort studies and the sampling and testing of humans and animals living in the same community, the frequent occurrence of infections with mixed genotypes and subtypes, and the apparent heterozygosity at some genetic loci for some G. duodenalis genotypes. With the increased usage of multilocus genotyping tools, the development of next-generation subtyping tools, the integration of molecular analysis in epidemiological studies, and an improved understanding of the population genetics of G. duodenalis in humans and animals, we should soon have a better appreciation of the molecular epidemiology of giardiasis, the disease burden of zoonotic transmission, the taxonomy status and virulences of various G. duodenalis genotypes, and the ecology of environmental contamination.

Genetics, chromatin diminution, and sex chromosome evolution in the parasitic nematode genus Strongyloides

BACKGROUND

When chromatin diminution occurs during a cell division a portion of the chromatin is eliminated, resulting in daughter cells with a smaller amount of genetic material. In the parasitic roundworms Ascaris and Parascaris, chromatin diminution creates a genetic difference between the soma and the germline. However, the function of chromatin diminution remains a mystery, because the vast majority of the eliminated DNA is noncoding. Within the parasitic roundworm genus Strongyloides, S. stercoralis (in man) and S. ratti (in rat) employ XX/XO sex determination, but the situation in S. papillosus (in sheep) is different but controversial.

RESULTS

We demonstrate genetically that S. papillosus employs sex-specific chromatin diminution to eliminate an internal portion of one of the two homologs of one chromosome pair in males. Contrary to ascarids, the eliminated DNA in S. papillosus contains a large number of genes. We demonstrate that the region undergoing diminution is homologous to the X chromosome of the closely related S. ratti. The flanking regions, which are not diminished, are homologous to the S. ratti autosome number I. Furthermore, we found that the diminished chromosome is not incorporated into sperm, resulting in a male-specific transmission ratio distortion.

CONCLUSIONS

Our data indicate that on the evolutionary path to S. papillosus, the X chromosome fused with an autosome. Chromatin diminution serves to functionally restore an XX/XO sex-determining system. A consequence of the fusion and the process that copes with it is a transmission ratio distortion in males for certain loci.

Enteropathogens and risk factors for diarrhea in Norwegian dairy calves

The aims of the current study were to estimate the prevalence of enteropathogens in calves in Norwegian dairy herds, evaluate the clinical consequences of protozoal infections, and identify risk factors for diarrhea. The 135 participating herds were randomly selected from those in The Norwegian Dairy Herd Recording System that had at least 15 cow-years. Each herd was followed for 1 yr. Fecal samples from calves with (n = 68) or without (n = 691) diarrhea were analyzed for the presence of Cryptosporidium, Giardia, and Eimeria species. Diarrheic samples (n = 191) were assayed for rotavirus group A, bovine coronavirus (BCoV), Cryptosporidium, and Escherichia coli F5 by antigen ELISA. Blood samples (n = 1,348) were analyzed for antibodies against BCoV and rotavirus. Potential risk factors for diarrhea were analyzed by using Cox regression analysis adjusted for herd frailty effect. Rotavirus and Cryptosporidium were the most commonly detected enteropathogens in diarrheic samples. A high level of Cryptosporidium shedding or BCoV seropositive calves in a herd was associated with an increased risk of diarrhea. Other factors found to increase the risk of diarrhea were use of slatted concrete floor in group pens versus other floor types [hazard ratio (HR) = 8.9], housing of calves in free-stalls compared with tie-stalls (HR = 3.7), purchasing of calves into the herd versus not purchasing calves (HR = 4.1), and calves being born during winter compared with other seasons of the year (HR = 1.5).

Effects of pastures' re-wetting on endoparasites in cattle in northern Germany

The influence of re-wetting of pastures on the occurrence of important endoparasites in cattle was monitored over the course of three years. The study was conducted on a peninsula at the German North-Sea Coast. The cattle were stabled from November to April. During summer season, they were kept on pastures included in a nature protection program differentiating between three states of re-wetting. Faecal samples from randomly selected animals were analysed with routine diagnostic methods for the occurrence of Eimeria spp., nematode and trematode eggs and lungworm larvae. Samples were taken three times per year: before turning out, in the middle of the grazing season and at the end. After a diagnostic and plausibility check, a total of 692 samples could be used for statistical analysis. The overall prevalence was 29.5% for Eimeria spp. and 42.2% for nematodes. Eggs of the liver fluke and lungworm larvae were only detected at very low levels. Statistical analyses were performed with a generalized linear model including the fixed effects wetting status, farm, year, and if it was the first summer on pasture for the animal. Significant influences on nematodes were detected for the stage of re-wetting, while Eimeria spp. were significantly affected by the grazing period. These findings indicate that the important parasites liver fluke and lungworm have not hitherto been affected at all by re-wetting measures. Furthermore, the prevalence of nematodes and Eimeria spp. did not increase. In conclusion, no clinical signs for parasitic diseases and no significantly elevated infection levels were shown after the third year of re-wetting, but even longer observations are essential to evaluate long-term consequences.

The Strongyloides (Nematoda) of sheep and the predominant Strongyloides of cattle form at least two different, genetically isolated populations

Strongyloides sp. (Nematoda) are very wide spread small intestinal parasites of vertebrates that can form a facultative free-living generation. Most authors considered all Strongyloides of farm ruminants to belong to the same species, namely Strongyloides papillosus (Wedl, 1856). Here we show that, at least in southern Germany, the predominant Strongyloides found in cattle and the Strongyloides found in sheep belong to separate, genetically isolated populations. While we did find mixed infections in cattle, one form clearly dominated. This variety, in turn, was never found in sheep, indicating that the two forms have different host preferences. We also present molecular tools for distinguishing the two varieties, and an analysis of their phylogenetic relationship with the human parasite Strongyloides stercoralis and the major laboratory model species Strongyloides ratti. Based on our findings we propose that Strongyloides from sheep and the predominant Strongyloides from cattle should be considered separate species as it had already been proposed by [Brumpt, E., 1921. Recherches sur le determinisme des sexes et de l'evolution des Anguillules parasites (Strongyloides). Comptes rendu hebdomadaires des séances et mémoires de la Société de Biologie et de ses filiales 85, 149-152], but was largely ignored by later authors. For nomenclature, we follow [Brumpt, E., 1921. Recherches sur le determinisme des sexes et de l'evolution des Anguillules parasites (Strongyloides). Comptes rendu hebdomadaires des séances et mémoires de la Société de Biologie et de ses filiales 85, 149-152] and use the name S. papillosus for the Strongyloides of sheep and the name Strongyloides vituli for the predominant Strongyloides of cattle.

Cryptosporidium parvum infection in cattle: are current perceptions accurate?

The perception that cattle are major reservoirs for Cryptosporidium parvum infections in humans and that C. parvum is a major cause of diarrhea and production loss in cattle might not reflect the whole situation. Numerous management factors influence the epidemiological and clinical picture associated with C. parvum infections in cattle. Whereas C. parvum is highly prevalent in young dairy calves and confined beef calves, it occurs rarely in calves on range and in adult cattle. In well-managed herds, clinical disease due to C. parvum is also rare. Therefore, C. parvum infections in cattle might not be as important as current perceptions would indicate.

The free-living generation of the nematode Strongyloides papillosus undergoes sexual reproduction

The nematode genus Strongyloides consists of parasites that live as parthenogenetic females in the small intestines of their hosts. They can also form a facultative free-living generation with males and females. Recently, research on Strongyloides cellular and molecular biology has concentrated on Strongyloides ratti and Strongyloides stercoralis. We propose that the related nematode Strongyloides papillosus, a common parasite of ruminants, is well suited for comparative and evolutionary studies and we show that it is phylogentically basal to S. ratti and S. stercoralis. Based on cytological observations several reports have proposed that Strongyloides males do not contribute genetically to the next generation, leaving open the question of why males still exist. In contrast, the only study employing molecular markers showed that S. ratti males do pass on genetic material. Here, we demonstrate that in S. papillosus males also contribute molecular genetic markers to the next generation. This is interesting for two reasons. First, it shows that S. papillosus is amenable to genetic analysis and second, it indicates that sexual reproduction is more common in Strongyloides than previously assumed.

Giardia and Cryptosporidium in water buffaloes (Bubalus bubalis)

A cross-sectional survey of Giardia duodenalis and Cryptosporidium parvum infection in the water buffalo (Bubalus bubalis) was carried out in central Italy. A geographical information system (GIS) was constructed utilizing as data-layers the topographic base map and the digital aerial photographs of the study area, as well as the geo-referenced points of all the buffalo farms. The survey was conducted on a sample of 90 farms, selected using a grid approach followed by proportional allocation. For this purpose, a grid representing quadrants of 5 x 5 km was overlaid on the study area within the GIS. As a result, the study area was divided in equal quadrants, and the number of farms sampled in each quadrant was proportional to the total number of study population in that quadrant. On each farm, faecal samples were collected per rectum from three to five asymptomatic buffalo calves, aged from 1 to 9 weeks. The total number of faecal samples collected was 347. Each faecal sample was tested for the presence of copro-antigens of G. duodenalis and of C. parvum using two commercially available enzyme-linked immunosorbent assays. Out of the 90 farms, 27 (30.0%) resulted positive for G. duodenalis and 22 (24.4%) for C. parvum. Co-infection was found in ten (11.1%) farms. With respect to animals, out of the 347 faecal samples, 63 (18.1%) were found to have antigens of G. duodenalis and 51 (14.7%) of C. parvum. Co-infection was found in ten buffalo calves (2.9%). The results of the logistic regression models showed a positive association between the positivity to G. duodenalis and the presence of sheep on farm and between the positivity to C. parvum and the high number of buffaloes on farms. No significant co-infection between the two protozoa was found. In conclusion, the findings of the present study, derived from a systematic territorial survey planned with GIS, are noteworthy because they provided additional data on C. parvum and the first evidence of G. duodenalis infection in water buffaloes.

Giardiasis and cryptosporidiosis in ruminants

Although they differ considerably with respect to their biology, both Giardia duodenalis and Cryptosporidium parvum are common in ruminants, whereas Cryptosporidium andersoni is not. G. duodenalis infections are acquired during the first few months of life, tend to be chronic, and may be a production-limiting disease of ruminants. C. parvum infections remain an important cause of diarrhea in neonatal ruminants. Abomasal cryptosporidiosis, caused by C. andersoni, is an emerging disease of cattle that may affect both beef and dairy herds. This article reviews the life cycles, production impacts, treatments, controls, and zoonotic potentials of these important ruminant parasites.