Role of Rhipicephalus bursa larvae in transstadial transmission and endemicity of Babesia ovis in chronically infected sheep.

Babesia ovis, transmitted by Rhipicephalus bursa ticks, is the causative agent of ovine babesiosis, a disease characterized by fever, anemia, hemoglobinuria, and high mortality in sheep. This study investigates whether sheep that survived babesiosis without treatment can serve as a source of infection for B. ovis-free host-seeking R. bursa larvae in a later season. Three donor sheep were experimentally infected with B. ovis, and after six months, persistence of B. ovis was assessed through blood and tick transmission experiments. Blood from donor sheep was intravenously injected into three recipient sheep, while donor sheep were also infested with B. ovis-free R. bursa larvae. Engorged nymphs molted to adults, and new recipient sheep were infested with these ticks. All recipient sheep were monitored for B. ovis for 100 days using microscopic, serological, and molecular approaches. The presence of B. ovis was confirmed in the recipient sheep that received blood, leading to clinical infection in two. However, no B. ovis was detected in recipient sheep infested with ticks. These results suggest that sheep recovering from B. ovis infection do not serve as a source of infection for R. bursa larvae in subsequent seasons.

Treatment and management of coenurosis by Taenia multiceps: field data from outbreaks in endemic regions and literature review.

BACKGROUND: Taenia multiceps coenurosis is endemic in sheep from various regions worldwide. Dogs, the key hosts, shed T. multiceps eggs in their feces contaminating the pasture, and lambs are mostly infected during their first turnout into pastures. The disease is manifested in two forms: acute (due to the migrating oncospheres in the CNS) or chronic (due to the developing coenuri in the brain or spinal cord). Both forms are frequently accompanied by neurological symptoms. METHODS: Field trials conducted in an endemic region (Sardinia, Italy) to treat replacement lambs in six sheep flocks infected with acute coenurosis are summarized in this article. The article also reviews earlier reports on various approaches developed to treat and immunize sheep against coenurosis. RESULTS: Accurate detection of the time in which lambs become infected is crucial in deciding which treatment approach should be used. Acute disease can be successfully treated via chemotherapy. Results of field trials conducted in Sardinia revealed the efficacy of three (1-week apart) oxfendazole doses (14.15 mg/kg) in protecting apparently healthy lambs in the infected flocks from developing neurological symptoms. A single praziquantel dose (18.75 mg/kg) worked well for the same purpose and was also found significant in treating 5 of 16 clinically ill lambs in one flock. Earlier reports documented high rates of recovery (up to 100%) in clinically diseased lambs that received much higher doses (50-100 mg/kg) of praziquantel. However, chemotherapy is not preferred in chronic coenurosis since it can lead to rupture of the coenuri, giving rise to serious inflammation in the CNS. Surgical intervention is highly recommended in this case, and the pooled success rates for surgery in chronic-infected cases was estimated at 82.1% (95% CI 73.1-91.0%). However, various trials have been conducted to immunize sheep against T. multiceps coenurosis, and the 18k (Tm18) family of oncosphere antigens was found promising as a vaccine candidate. CONCLUSIONS: In acute coenurosis, selection of the proper anthelmintic should be done after consulting the owner for several reasons: (1) costs of the used anthelmintic: treating a small flock of 100 sheep costs around 1170 and 660 € for praziquantel and oxfendazole, respectively; (2) withdrawal time of the used anthelmintic: No time is required before consuming meat and milk from praziquantel-treated sheep, whereas meat and milk from oxfendazole-treated sheep should not be consumed for 44 and 9 days, respectively, causing additional costs for the farmers. Since no commercial vaccines have yet been developed against T. multiceps coenurosis in sheep, preventive measures remain the cornerstone of controlling this serious disease.

A pilot study of the in vitro efficacy of different concentrations of Duddingtonia flagrans for the control of gastrointestinal nematodes of sheep.

Duddingtonia flagrans is a nematode trapping fungus used for the control of gastrointestinal nematodes in livestock. The quantity of chlamydospores of D. flagrans required for the reduction of third-stage larvae (L3) of sheep gastrointestinal nematodes (GIN) is largely unknown, and a matter of discussion. The aim of this experiment was to determine in vitro the nematophagous activity of four different concentrations of D. flagrans (1000, 3000, 6250, or 11000 chlamydospores/ml) in the presence of varying numbers of GIN third-stage larvae (L3) (500, 1000, 1500). Additionally, the study sought to evaluate the efficacy of this fungus on Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus colubriformis and Chabertia ovina. The results showed that as fungal concentrations increased, so did the larval reduction of third-stage infective larvae in each test. L3s number was not a determining factor in the efficacy against GIN. The comparison between various concentrations of chlamydospores revealed significant differences, particularly between 1000 and 11000 chlamydospores (P≤0.05). Regarding the larval reduction of the GIN species considered, D. flagrans demonstrated the same effectiveness across all species tested. The results of the current study confirm the efficacy and underscore the importance of D. flagrans as an alternative for controlling of GIN.

The first molecular detection of benzimidazole resistance in Haemonchus contortus from sheep in Hejing and Minfeng counties of Southern Xinjiang.

To understand the benzimidazole (BZ) resistance of Haemonchus contortus in Southern Xinjiang, three single nucleotide polymorphisms (SNPs) designated as F167Y, E198A, and F200Y, in the isotype-1 ß-tubulin gene which are associated with BZ resistance, were investigated for H. contortus populations from sheep in Hejing and Minfeng counties of Southern Xinjiang. In brief, a total of 190 H. contortus adults were collected from 52 out of 70 slaughtered sheep in city abattoirs across two regions in Southern Xinjiang. The species identity of each adult worm was confirmed by PCR amplification of ITS-2 using H. contortus-specific primers targeting the ITS-2. The samples were then investigated for BZ-related SNPs at locus 167, 198, and 200, by PCR-sequencing of the isotype-1 ß-tubulin gene. The results showed that only E198A and F200Y mutations were detected in the investigated H. contortus populations. The E198A mutation (homozygous and heterozygote resistant: found in 40% and 30% of sequenced samples from Minfeng and Hejing counties, respectively) was predominant compared with the F200Y mutation (homozygous and heterozygote resistant: found in 14% and 13.3% of sequenced samples from Minfeng and Hejing counties, respectively). The results indicate a high prevalence of BZ resistance in H. contortus populations from certain areas of Southern Xinjiang. Our findings provide valuable information for the prevention and control of H. contortus in areas with similar conditions.

Biomolecular survey on the main infectious causes of abortion in sheep in the Italian regions of Latium and Tuscany.

Background: Ruminants play an important role in economic sustenance in many developing countries. Abortion is one of the most important causes of economic losses in sheep livestock and, for this reason, it is very important to know, at an early stage, which pathogens caused abortion. Aim: The aim of the study is to obtain data about the distribution of abortifacient pathogens in the Italian regions of Latium and Tuscany, the awareness of the distribution of infectious agents causing abortion could allow the development of an appropriate vaccination and prophylaxis plan, to avoid major economic losses. Methods: 388 abortions were collected during the 2015-2018 period. Organs, tissues, and swabs were subjected to DNA extraction and then analyzed with commercial q-PCR kits for the detection of the most common abortion pathogens circulating in these geographical areas. Results: The positivity in 148 abortions was 56% for Chlamydia abortus, 14% for Coxiella burnetii, 16% for Salmonella spp, 12% for Toxoplasma gondii, and 2% for Neospora caninum. Interesting results were obtained for cases of abortions with co-infection of abortion pathogens. Conclusion: Diagnosing the cause of abortion remains a multifaceted process that may also include non-infectious factors such as deficiencies and toxicities. Further research is needed also to assess the role of low pathogen concentrations and co-infections in the abortions of sheep.

Ovicidal activity and cytotoxicity of ethanolic extract of turmeric (Curcuma longa) and green tea (Camellia sinensis) to treat digestive parasite of sheep.

Background: The Trichuris eggs are collected from naturally infected sheep. Natural antihelmintics such as herbal medicines are needed as an alternative, such as natural compounds from endemic plants. Aim: This present study aims to evaluate the ovicidal activity and cytotoxicity effects of ethanolic extract of Curcuma longa (EECL) and Camelia sinensis (EECS) as a biological anthelmintic against the egg of Trichuris sp. Methods: The Trichuris eggs are collected from naturally infected sheep. CMC-Na solution 1% was used as a control. The treatments were 0.12% EECL; 0.24% EECL; 0.15% EECS; 0.30% EECS; a combination of 0.12% EECL and 0.30% EECS; a combination of 0.24% EECL; and 0.15% EECS. Ovicidal activity testing by microscopic examination of eggs treated using different concentrations of EECL extract, EECS, and a combination of them. They were exposed for various times (7, 14, 21, and 28 days) and incubated at room temperature. Results: The study shows that a combination of C. longa extract and tea extract exhibits good ovicidal anthelmintic activity against Trichuris sp. in sheep. Cytotoxicity examination using the 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT) test. Based on MTT data processed using regression analysis, the obtained LC50 from the administration of EECL, EECS, and a combination of both in a ratio of 1:1, 2:2, 1:2, and 2:1. The combination of EECL extract and EECS with the highest concentration produced cell viability of 28.46%, 17.25%, 56.01%, and 46.47%, respectively. Conclusion: It can be concluded that the most cytotoxic ingredient is found in the combination of EECL and EECS (2:2) at 17.25% and the safest is in the ratio (1:2) at 56.01%.

Diversity of hard ticks parasitizing farm animals in the Qarabulli region, Northwestern Libya.

Background: There are 26 species of ticks known to exist in Libya. Despite the presence of a number of investigations on ticks in Libya, there are no published studies on ticks in the Al-Qarboulli area. Aim: The aim of this study was to identify the tick species infesting farm animals in the Qarabulli region. Methods: Ticks were collected manually on a monthly basis from the examined hosts (cattle, sheep, dogs, and camels) that were selected randomly in the period between July 2021 and June 2022. Results: A total of 717 ticks were collected on 775 hosts, eight tick species were encountered: Hyalomma excavatum (41.00%), Rhipicephalus sanguineus (23.43%), Hyalomma dromedarii (12.13%), Hyalomma marginatum (9.21%), Hyalomma anatolicum (8.51%), Rhipicephalus annulatus (5.30%), Hyalomma rufipes (0.28%), and Boophilus microplus (0.14%). The mean prevalence of all species was 22.32%. The mean intensity of all species was 0.93 ticks per host. The presence of ticks among the months of the year varied among tick species. Conclusion: The results showed high tick infestation in farm animals of Qarabulli, Libya, suggesting an increased risk of tick-borne diseases. This highlights the need for preventative measures and public awareness to reduce tick populations. Further studies are recommended to understand the spread of tick-borne diseases in the area.

Moniezia benedeni drives the SNAP-25 expression of the enteric nerves in sheep's small intestine.

BACKGROUND: The neuroimmune network plays a crucial role in regulating mucosal immune homeostasis within the digestive tract. Synaptosome-associated protein 25 (SNAP-25) is a presynaptic membrane-binding protein that activates ILC2s, initiating the host's anti-parasitic immune response. METHODS: To investigate the effect of Moniezia benedeni (M. benedeni) infection on the distribution of SNAP-25 in the sheep's small intestine, the recombinant plasmid pET-28a-SNAP-25 was constructed and expressed in BL21, yielding the recombinant protein. Then, the rabbit anti-sheep SNAP-25 polyclonal antibody was prepared and immunofluorescence staining was performed with it. The expression levels of SNAP-25 in the intestines of normal and M. benedeni-infected sheep were detected by ELISA. RESULTS: The results showed that the SNAP-25 recombinant protein was 29.3 KDa, the titer of the prepared immune serum reached 1:128,000. It was demonstrated that the rabbit anti-sheep SNAP-25 polyclonal antibody could bind to the natural protein of sheep SNAP-25 specifically. The expression levels of SNAP-25 in the sheep's small intestine revealed its primary presence in the muscular layer and lamina propria, particularly around nerve fibers surrounding the intestinal glands. Average expression levels in the duodenum, jejunum, and ileum were 130.32 pg/mg, 185.71 pg/mg, and 172.68 pg/mg, respectively. Under conditions of M. benedeni infection, the spatial distribution of SNAP-25-expressing nerve fibers remained consistent, but its expression level in each intestine segment was increased significantly (P < 0.05), up to 262.02 pg/mg, 276.84 pg/mg, and 326.65 pg/mg in the duodenum, jejunum, and ileum, and it was increased by 101.06%, 49.07%, and 89.16% respectively. CONCLUSIONS: These findings suggest that M. benedeni could induce the SNAP-25 expression levels in sheep's intestinal nerves significantly. The results lay a foundation for further exploration of the molecular mechanism by which the gastrointestinal nerve-mucosal immune network perceives parasites in sheep.

Unveiling the presence and genotypic diversity of Giardia duodenalis on large-scale sheep farms: insights from the Henan and Ningxia Regions, China.

BACKGROUND: The parasitic protozoan Giardia duodenalis is an important cause of diarrheal disease in humans and animals that can be spread by fecal-oral transmission through water and the environment, posing a challenge to public health and animal husbandry. Little is known about its impact on large-scale sheep farms in China. In this study we investigated G. duodenalis infection of sheep and contamination of the environment in large-scale sheep farms in two regions of China, Henan and Ningxia. METHODS: A total of 528 fecal samples, 402 environmental samples and 30 water samples were collected from seven large-scale sheep farms, and 88 fecal samples and 13 environmental samples were collected from 12 backyard farms. The presence of G. duodenalis was detected by targeting the ß-giardin (bg) gene, and the assemblage and multilocus genotype of G. duodenalis were investigated by analyzing three genes: bg, glutamate dehydrogenase (gdh) and triphosphate isomerase (tpi). RESULTS: The overall G. duodenalis detection rate was 7.8%, 1.4% and 23.3% in fecal, environmental and water samples, respectively. On the large-scale sheep farms tested, the infection rate of sheep in Henan (13.8%) was found to be significantly higher than that of sheep in Ningxia (4.2%) (P < 0.05). However, the difference between the rates of environmental pollution in Henan (1.9%) and Ningxia (1.0%) was not significant (P > 0.05). Investigations of sheep at different physiological stages revealed that late pregnancy ewes showed the lowest infection rate (1.7%) and that young lambs exhibited the highest (18.8%). Genetic analysis identified G. duodenalis belonging to two assemblages, A and E, with assemblage E being dominant. A total of 27 multilocus genotypes were identified for members of assemblage E. CONCLUSIONS: The results suggest that G. duodenalis is prevalent on large-scale sheep farms in Henan and Ningxia, China, and that there is a risk of environmental contamination. This study is the first comprehensive examination of the presence of G. duodenalis on large-scale sheep farms in China. Challenges posed by G. duodenalis to sheep farms need to be addressed proactively to ensure public health safety.

Impacts of a highly pathogenic ovine Eimeria ovinoidalis on the growth of Hu lambs.

The apicomplexan Eimeria ovinoidalis is distributed worldwide. It can cause clinical coccidiosis, which is one of the most pathogenic species in sheep, reducing growth rates and resulting in significant economic losses in the industry. Its principal clinical sign is profuse diarrhoea in young animals. In this study, we established a model of E. ovinoidalis infection in lambs to understand its pathogenicity and evaluate the gut microbiota and fecal metabolite profiles. Specifically, we observed a significant shift in the abundance of bacteria and disrupted metabolism in lambs. Especially during the peak period of excrete oocysts, it promoted the reproduction of some harmful bacteria in Proteobacteria and Actinobacteriota, and reduced the abundance of beneficial bacteria such as Lachnospiraceae and Rikenellaceae. In the later stage of the patent period, the abundance of harmful bacteria in the intestine decreased, the abundance of beneficial bacteria which could produce anti-inflammatory substances began to increase, and the abundance and diversity of intestinal flora also tended to parallel with the control group. Coccidia infection could lead to the increase of differential metabolites and metabolic pathways between infected and control group, but the difference decreased with time. During the peak period of excrete oocysts, although the antimicrobial metabolites such as Lividamine were up-regulated, the excess of these metabolites could still induce the production of endotoxin, while Butanoic acid and other anti-inflammatory metabolites decreased significantly. A metabolomics analysis showed that E. ovinoidalis infection altered metabolites and metabolic pathways, with biosynthesis of unsaturated fatty acids, Teichoic acid biosynthesis and Butanoate metabolism as the major disrupted metabolic pathways. Details of the gut microbiota and the metabolome after infection with E. ovinoidalis may aid in the discovery of specific diagnostic markers and help us understand the changes in parasite metabolic pathways.

Inconsistency of in vitro exsheathment triggers for gastrointestinal nematode parasites of sheep, cattle and deer.

Exsheathment is crucial in the transition from free-living to parasitic phase for most strongyle nematode species. A greater understanding of this process could help in developing new parasitic control methods. This study aimed to identify commonalities in response to exsheathment triggers (heat acclimation, CO2 and pH) in a wide range of species (Haemonchus contortus, Trichostrongylus spp., Cooperia spp., Oesophagostomum spp., Chabertia ovina, and members of the subfamily Ostertagiinae) from sheep, cattle and farmed deer. The initial expectation of similarity in pH requirements amongst species residing within the same organ was not supported, with unexpected pH preferences for exsheathment of Trichostrongylus axei, Trichostrongylus vitrinus, Trichostrongylus colubriformis and Cooperia oncophora. We also found differences between species in their response to temperature acclimation, with higher exsheathment in response to heat shock observed for H. contortus, Ostertagia ostertagi, T. axei, T. vitrinus and Oesophagostomum sikae. Furthermore, some species showed poor exsheathment under all experimental conditions, such as Cooperia curticei and the large intestinal nematodes C. ovina and Oesophagostomum venulosum. Interestingly, there were some significant differences in response depending on the host from which the parasites were derived. The host species significantly impacted on the exsheathment response for H. contortus, Teladorsagia circumcincta, T. vitrinus and T. colubriformis. Overall, the data showed variability between nematode species in their response to these in vitro exsheathment triggers, highlighting the complexity of finding a common set of conditions for all species in order to develop a control method based on triggering the exsheathment process prematurely.

Identification and prevalence of ticks infesting small ruminants of Fort Munro region in South Punjab, Pakistan.

Fort Munro is a hill station in Southern Punjab the residents of whom are heavily dependent upon livestock for their living but ticks are a big treat for the livestock. The purpose of this study was to ascertain the tick infestation among the small ruminants of Fort Munro. Ticks (N = 273) were collected from 333 animals (165 goats and 168 sheep) during August and September 2022. Two tick genera Hyalomma and Rhipicephalus were identified. Rhipicephalus was most abundant tick genera (78.02%) followed by Hyalomma (21.98%).Tick distribution significantly varied with the host: Rhipicephalus ticks were more frequently infesting goats while Hyalomma were more common on sheep. For both hosts, tick infestation varied with the sampling sites and male animals were significantly more infested than females. Five tick species were infesting goats with the following relative abundance: Rhipicephalus (R.) senegalensis (39.20%) > R. sanguineus (36.8%) > R. appendiculatus (10.40%) > R. turanicus (8%) > R. guilhoni (5.6%). Rhipicephalus senegalensis (41.22%) was also the most common tick species infesting sheep followed by Hyalomma (H.) marginatum (29.73%), R. guilhoni (18.24%), H. dromedarii (5.41%) and H. impeltatum (5.41%). Male ticks very more abundantly on both goats and sheep than female. Distribution of Hyalomma species also varied between the sampling sites. In conclusion, we are reporting the infestation of 3 Hyalomma and 5 Rhipicephalus in small ruminants of Fort Munro. The data generated through this study will help in developing appropriate tick control in the study area and will add to the existing knowledge regarding tick species that are infesting the small ruminants of Pakistan.

Ovine dicrocoeliosis in Castellón province, eastern Spain: Prevalence, dynamics, and comparative study of different diagnostic techniques.

Dicrocoeliosis is a parasitic disease that mainly affects ruminants during grazing, caused by trematodes of the genus Dicrocoelium, with D. dendriticum being the most common species worldwide. This parasitosis is a chronic and generally subclinical process, with nonspecific signs, which makes its diagnosis challenging. This study aimed to determine the prevalence and seasonal dynamics of D. dendriticum infection in adult sheep from the Valencian Community, eastern Spain, as well as to evaluate the efficacy of flotation and sedimentation techniques when compared with the macroscopic exam of the liver. From February to May 2018, 2019, 2020, 2021, and 2022, a total of 290 adult sheep were examined. The animals were sourced from Castellón province, where a semi-intensive production system predominates. Each animal was euthanized and underwent a macroscopic examination of the liver, as well as a fecal analysis. Among the sampled animals, 117 (40.6%) tested positive for adult trematodes in their liver, while 87 (30%) showed evidence of trematode eggs in the coprological exam, reaching a total of 126 sheep parasitized, with a prevalence of 43.4%. The parasitic burden was established in 90.3 adults per animal when the liver was examined and in 54.5 eggs per gram when the sedimentation coprological exam was performed. No eggs were observed when the flotation technique was employed. A positive correlation was found between the number of adults in the liver and the fecal egg count. No significant differences were detected in the prevalence or parasitic burden throughout the study. Considering the difficulty in controlling the intermediate hosts and the complexity of the life cycle, effective diagnostic methods, combined with the adoption of other preventive measures, is crucial to achieving proper management of this parasitic disease.

Frequency of Besnoitia besnoiti and Neospora caninum antibodies in cattle and small ruminants from greater Cairo and Beni Suef governorates, Egypt.

Livestock industry is a pivotal sector for providing food, work places and monetary support for Egyptian people. Besnoitia besnoiti and Neospora caninum are protozoan parasites that are responsible for significant economic losses in ruminants, particularly in cattle. Besnoitia besnoiti can cause fertility problems and a general loss in productivity, while N. caninum is a major cause of abortion and neonatal abnormalities in infected animals. There is little information on the existence of these protozoa in Egypt, thus we conducted this study to reveal the current situation in cattle (n = 264), sheep (n = 151), and goats (n = 25). Serum samples were collected from governorates of Cairo, Giza, and Beni Suef, representing the most densely populated regions in Egypt. Using commercial ELISAs, an overall estimation among all tested animals (n = 440) revealed 7.7%, 13.2%, and 0.9% as seropositive rates for B. besnoiti, N. caninum, and mixed infection, respectively. Animal species (cattle vs sheep vs goat) and age of cattle (less than vs >1 year old) were analyzed as risk factors for infection. Regarding B. besnoiti, the seroprevalence was significantly higher in cattle than in sheep and goats and in adult cattle than calves. For N. caninum infection, no significant differences were recorded, although the seropositive rates were higher in cattle, and in adult cattle. This study provides the first seroprevalence data for B. besnoiti in all surveyed animals in the regions included, and in sheep and goats from Egypt, and supports the current knowledge for the occurrence of N. caninum in Egypt.

Prevalence and risk factors for gastrointestinal parasitosis in small ruminant farms in the Sahelian zone of Niger.

The general aim of this study is to analyse the risk factors for gastrointestinal parasitosis in small ruminants in order to contribute to the emergence of targeted treatment methods, at herd and agro-climatic zone levels, for the integrated and sustainable management of parasitic diseases in Sahelian livestock systems. The methodology was based on a questionnaire survey conducted in 37 villages and coprological analysis using the McMaster method on faecal samples from 968 small ruminants, including 555 goats and 413 sheep. Multiple logistic regression was used to highlight the risk factors associated with each type of parasitosis encountered. The results showed that the most widespread farming system remained 100% traditional, with feeding based essentially on natural grazing. Coprological results showed the prevalence of nematodosis (70.2%), Cestodosis (4.1%) and Coccidiosis (79.9%), with an average prevalence of coinfection of 56.9%. These parasite loads were significantly higher during the rainy season and in the more arid northern Sahelian zone, with a marked reduction at the end of the season. Average parasitic egg excretions were 1089 EPG of nematodes and 6864 EPG of coccidia. Parasite loads were higher in the wetter southern strip and varied significantly by breed. Of the five breeds of small ruminants studied, the ara-ara sheep had the highest parasitic loads and prevalences for nematodosis (78.6%), coccidiosis (89,3%) and coinfection (70.9%), appears to be the most susceptible to parasitosis. As for risk factors for severe parasite pressure, animals at the end of the rainy season, older animals and those with poor body condition were at risk of nematodiasis or coinfection. On the other hand, animals at the beginning of the rainy season, farms located in less arid southern Sahelian zones and male subjects were the groups at significant risk of coccidiosis. In these extensive Sahelian farming conditions, the control of these parasitoses by selective treatment of animals could be developed, targeting in particular the risk groups highlighted in this study.

Genomic Regions Associated with Resistance to Gastrointestinal Parasites in Australian Merino Sheep.

The objective of this study was to identify genomic regions and genes associated with resistance to gastrointestinal nematodes in Australian Merino sheep in Uruguay, using the single-step GWAS methodology (ssGWAS), which is based on genomic estimated breeding values (GEBVs) obtained from a combination of pedigree, genomic, and phenotypic data. This methodology converts GEBVs into SNP effects. The analysis included 26,638 animals with fecal egg count (FEC) records obtained in two independent parasitic cycles (FEC1 and FEC2) and 1700 50K SNP genotypes. The comparison of genomic regions was based on genetic variances (gVar(%)) explained by non-overlapping regions of 20 SNPs. For FEC1 and FEC2, 18 and 22 genomic windows exceeded the significance threshold (gVar(%) ≥ 0.22%), respectively. The genomic regions with strong associations with FEC1 were located on chromosomes OAR 2, 6, 11, 21, and 25, and for FEC2 on OAR 5, 6, and 11. The proportion of genetic variance attributed to the top windows was 0.83% and 1.9% for FEC1 and FEC2, respectively. The 33 candidate genes shared between the two traits were subjected to enrichment analysis, revealing a marked enrichment in biological processes related to immune system functions. These results contribute to the understanding of the genetics underlying gastrointestinal parasite resistance and its implications for other productive and welfare traits in animal breeding programs.

Chromosome-Scale Genome Assembly of the Sheep-Biting Louse Bovicola ovis Using Nanopore Sequencing Data and Pore-C Analysis.

Bovicola ovis, commonly known as the sheep-biting louse, is an ectoparasite that adversely affects the sheep industry. Sheep louse infestation lowers the quality of products, including wool and leather, causing a loss of approximately AUD 123M per annum in Australia alone. The lack of a high-quality genome assembly for the sheep-biting louse, as well as any closely related livestock lice, has hindered the development of louse research and management control tools. In this study, we present the assembly of B. ovis with a genome size of ~123 Mbp based on a nanopore long-read sequencing library and Illumina RNA sequencing, complemented with a chromosome-level scaffolding using the Pore-C multiway chromatin contact dataset. Combining multiple alignment and gene prediction tools, a comprehensive annotation on the assembled B. ovis genome was conducted and recalled 11,810 genes as well as other genomic features including orf, ssr, rRNA and tRNA. A manual curation using alignment with the available closely related louse species, Pediculus humanus, increased the number of annotated genes to 16,024. Overall, this study reported critical genetic resources and biological insights for the advancement of sheep louse research and the development of sustainable control strategies in the sheep industry.

Molecular prevalence, associated risk factors and phylogenetic evaluation of Theileria lestoquardi in the blood samples of small ruminants.

Raising small ruminants is the main source of income for farmers in Pakistan especially in rural areas of Dera Ghazi Khan in Punjab. Despite having large sheep population, the prevalence of intra-erythrocytic protozoa, Theileria (T.) lestoquardi, has never been reported from this area. This study was conducted to fill this knowledge gap and 333 blood samples of apparently healthy small ruminants (168 sheep and 165 goats) along with their epidemiological data were collected from Dera Ghazi Khan district during August till November 2022. The polymerase chain reaction (PCR) analysis amplified a 785 base pair amplicon specific for the Merozoite surface antigen (ms 1-2) gene of T. lestoquardi in 2 out of the 168 (3.3%) sheep blood samples, while no goat blood sample out of 165 was found to be infected with T. lestoquardi. DNA sequencing confirmed the presence of Theileria lestoquardi in both samples and phylogenetic analysis revealed that these amplicon resembled the partial ms 1-2 gene sequences detected in small ruminants from Pakistan, India Iran and Egypt. All the studied epidemiological factors (age, sex, breed, size of herd, dogs with herd, composition of herd, size of herd and Tick burden on sheep) were not found associated with the prevalence of T. lestoquardi. In conclusion, this study reports a low prevalence of T. lestoquardi infection in the Dera Ghazi Khan District of Punjab, Pakistan. The data generated from this work will help pave the way for the prophylactic detection and control of ovine and caprine theileriosis in the region.

Divergent humoral responses between males and females against 24 kDa excretory-secretory protein of Haemonchus contortus and influence of ovine ß-globin polymorphism.

Lambs harboring the Hb-AA ß-globin haplotype present improved cell-mediated responses and increased resistance against Haemonchus contortus infection. The aim of the present study was to compare the effect of sex and ß-globin haplotypes on specific humoral responses and phenotypes of resistance during H. contortus infection in Morada Nova sheep. As expected, females displayed stronger resistance during the first and second experimental challenges. Differential systemic humoral immune responses were observed comparing sex groups, in which higher levels of specific antibodies targeting 24 kDa excretory-secretory (ES24) protein of H. contortus of IgG and IgM antibodies were respectively observed as predominant isotypes in males and females. The IgM levels were significantly correlated with phenotypes of resistance, evaluated by packed cell volume and fecal egg counts. To our knowledge this is the first study reporting divergent humoral responses profiles to H. contortus infection between male and female sheep. The impact of ß-globin haplotypes was less pronounced in females compared to males. Notably, only males showed significant weight differences across haplotypes, with Hb-AA lambs being the heaviest. Additionally, Hb-AA males had significantly higher PCV (indicating better red blood cell health) and lower FEC (indicating lower parasite burden). These findings suggest a more pronounced effect of ß-globin polymorphisms on H. contortus infection in males, potentially due to their generally weaker resistance compared to females. This study highlights the importance of sex and ß-globin haplotypes in shaping immune responses to H. contortus infection. Specifically, IgM antibodies targeting the ES24 protein appear to play a crucial role in host-parasite interactions and may hold promise for therapeutic development.

Beyond parasitism: Exploring the microbial profile of Haemonchus contortus and its predilection site (abomasum) in Kashmir Merino sheep.

Gastrointestinal helminth infection, particularly by Haemonchus contortus, poses significant challenges to sheep farming worldwide. While anthelmintic drugs have been traditional control measures, the emergence of resistance calls for alternative strategies. Understanding the interaction between parasites, host, and their microbiome is crucial for management of helminth infection. This study intricately explores the interactions between microbial communities in Kashmir Merino sheep infected with H. contortus, to understand the complex interplay between host, parasite, and their microbiome. Sheep abomasal contents and H. contortus were collected from infected and control groups, processed for DNA extraction, and subjected to metagenomic sequencing of the 16 S rRNA gene. Downstream analysis unveils distinct microbial patterns, where Proteobacteria were dominant in H. contortus, while Bacteroidota and Firmicutes prevailed in the sheep abomasum. The revelation of unique genera and shifts in diversity indices underscored helminth-induced disruptions in the host. Beta diversity analysis further showed significant variations in bacterial profiles, providing insights into the intricate host, parasite, and microbiome dynamics. Additionally, this study elucidated the presence of pathogenic bacteria within H. contortus, accentuating their potential role in exacerbating sheep health issues. This finding underscores the complexity of the host-parasite-microbiome interaction showing helminth-induced microbiome alterations of the host.