Parasites Of Livestock Research Articles

Current and future trends in managing internal parasites in forage-based livestock

Current and future trends in managing internal parasites in forage-based livestock

Global analysis of neuropeptide receptor conservation across phylum Nematoda.

The phylum Nematoda is incredibly diverse and includes many parasites of humans, livestock, and plants. Peptide-activated G protein-coupled receptors (GPCRs) are central to the regulation of physiology and numerous behaviors, and they represent appealing pharmacological targets for parasite control. Efforts are ongoing to characterize the functions and define the ligands of nematode GPCRs, with already most peptide GPCRs known or predicted in Caenorhabditis elegans. However, comparative analyses of peptide GPCR conservation between C. elegans and other nematode species are limited, and many nematode GPCRs remain orphan. A phylum-wide perspective on peptide GPCR profiles will benefit functional and applied studies of nematode peptide GPCRs. We constructed a pan-phylum resource of C. elegans peptide GPCR orthologs in 125 nematode species using a semi-automated pipeline for analysis of predicted proteome datasets. The peptide GPCR profile varies between nematode species of different phylogenetic clades and multiple C. elegans peptide GPCRs have orthologs across the phylum Nematoda. We identified peptide ligands for two highly conserved orphan receptors, NPR-9 and NPR-16, that belong to the bilaterian galanin/allatostatin A (Gal/AstA) and somatostatin/allatostatin C (SST/AstC) receptor families. The AstA-like NLP-1 peptides activate NPR-9 in cultured cells and are cognate ligands of this receptor in vivo. In addition, we discovered an AstC-type peptide, NLP-99, that activates the AstC-type receptor NPR-16. In our pan-phylum resource, the phylum-wide representation of NPR-9 and NPR-16 resembles that of their cognate ligands more than those of allatostatin-like peptides that do not activate these receptors. The repertoire of C. elegans peptide GPCR orthologs varies across phylogenetic clades and several peptide GPCRs show broad conservation in the phylum Nematoda. Our work functionally characterizes the conserved receptors NPR-9 and NPR-16 as the respective GPCRs for the AstA-like NLP-1 peptides and the AstC-related peptide NLP-99. NLP-1 and NLP-99 are widely conserved in nematodes and their representation matches that of their receptor in most species. These findings demonstrate the conservation of a functional Gal/AstA and SST/AstC signaling system in nematodes. Our dataset of C. elegans peptide GPCR orthologs also lays a foundation for further functional studies of peptide GPCRs in the widely diverse nematode phylum.

Genomic data reveal a north-south split and introgression history of blood fluke (Schistosoma haematobium) populations from across Africa.

The human parasitic fluke, Schistosoma haematobium hybridizes with the livestock parasite S. bovis in the laboratory, but the extent of hybridization in nature is unclear. We analyzed 34.6 million single nucleotide variants in 162 samples from 18 African countries, revealing a sharp genetic discontinuity between northern and southern S. haematobium. We found no evidence for recent hybridization. Instead the data reveal admixture events that occurred 257-879 generations ago in northern S. haematobium populations. Fifteen introgressed S. bovis genes are approaching fixation in northern S. haematobium with four genes potentially driving adaptation. We identified 19 regions that were resistant to introgression; these were enriched on the sex chromosomes. These results (i) demonstrate strong barriers to gene flow between these species, (ii) indicate that hybridization may be less common than currently envisaged, but (iii) reveal profound genomic consequences of interspecific hybridization between schistosomes of medical and veterinary importance.

Anthelmintic activity of three selected ethnobotanical plant extracts against Strongyloides venezuelensis

The agropastoral farmers have employed Turraea vogelii(TVL),Senna podocarpa(SPL), and Jaundea pinnata (JPL) leaves for treating various diseases, including intestinal parasites in livestock and the human population in Nigeria. Gastrointestinal nematodes are highly significant to livestock production and people's health, and natural products are interesting as sources of new drugs. In this study, we evaluated the effectiveness of extracts derived from these plants in treating parasitic infections using third-stage infective larvae (L3) of Strongyloides venezuelensis. We obtained crude extracts using n-gexane (Hex), ethyl acetate (Ea), and methanol (Met). The extracts were analyzed for their phytochemical composition, and their ability to prevent hemolysis were tested. The mean concentrations of total phenols in SPL Hex, SPL Ea, and SPL Met were 92.3 ± 0.3, 103.0 ± 0.4, and 128.2 ± 0.5 mg/100 g, respectively. Total tannin concentrations for JPL Ea, SPL Ea, SPL Hex, and TVL Hex were 60.3 ± 0.1, 89.2 ± 0.2, 80.0 ± 0.1, and 66.6 ± 0.3 mg/100 g, respectively. The mean lethal concentration (LC50) at 72 h for JPL Ea 39 (26–61) μg/mL. SPL Ea was 39 (34–45) μg/mL, and TVL Hex 31 (26–36) μg/mL. The antiparasitic activities of the extracts against L3 were dose- and time-dependent. All the extracts were slightly hemolytic to the erythrocytes. In this study, the plant extract tested demonstrated significant anti-S. venezuelensis activity. These phytobotanical extracts could be used to create formulations for the potential treatment of helminthiasis in animals and humans.

Elucidating nematode diversity and prevalence in moose across a wide latitudinal gradient using DNA metabarcoding

Parasitic nematodes are ubiquitous and can negatively impact their host by reducing fecundity or increasing mortality, yet the driver of variation in the parasite community across a wildlife host's geographic distribution remains elusive for most species. Based on an extensive collection of fecal samples (n = 264) from GPS marked moose (Alces alces), we used DNA metabarcoding to characterize the individual (sex, age class) and seasonal parasitic nematode community in relation to habitat use and migration behavior in five populations distributed across a wide latitudinal gradient (59.6°N to 70.5°N) in Norway. We detected 21 distinct nematode taxa with the six most common being Ostertagia spp., Nematodirella spp., Trichostongylus spp., T. axei, Elaphostrongylus alces, and an unclassified Strongylida. There was higher prevalence of livestock parasites in areas with larger sheep populations indicating a higher risk of spillover events. The individual level nematode richness was mostly consistent across study areas, while the number and type of nematode taxa detected at each study area varied considerably but did not follow a latitudinal gradient. While migration distance affected nematode beta-diversity across all sites, it had a positive effect on richness at only two of the five study areas suggesting population specific effects. Unexpectedly, nematode richness was higher in winter than summer when very few nematodes were detected. Here we provide the first extensive description of the parasitic nematode community of moose across a wide latitudinal range. Overall, the population-specific impact of migration on parasitism across the distribution range and variation in sympatry with other ruminants suggest local characteristics affect host-parasite relationships.

Experimental evidence that dung beetles benefit from reduced ivermectin in targeted treatment of livestock parasites

Anthelmintic residues in livestock dung can adversely affect beneficial organisms. Targeted selective treatment (TST) of a reduced proportion of livestock with anthelmintics can slow resistance development in gastrointestinal nematodes by providing residue-free dung which could also benefit non-target organisms. We tested effects of TST on survival and reproduction of the dung beetle Onthophagus taurus (Scarabaeidae) in a factorial glasshouse experiment (Experimental treatments: five TST levels, 0.00, 0.25, 0.50, 0.75, 1.00 x four ivermectin concentrations, 125, 250, 375, 500 ppb). Each mesocosm comprised a 60 L bin containing sand, four dung pats and six pairs of adult beetles (F0 generation). No effects of TST level and ivermectin concentration on mortality of F0 adults after one week were observed. F0 adult brood ball production was affected by TST level, particularly at high ivermectin concentrations. Brood ball production increased as more untreated pats became available, with greater increases at higher ivermectin concentrations. We tested for evidence of a reported attraction of dung beetles to ivermectin-treated dung using a novel glitter-marker to trace the origin of dung used in brood balls. Where mesocosms contained both dung types, the proportion of brood balls created from untreated dung showed no statistical difference from the null expectation based on untreated dung availability in the mesocosm. Emergence of F1 adults was affected by the increase in TST, with this effect dependent on concentration. Treatments with concentrations of 250–500 ppb had the lowest emergence rates (ca. 5–20 % in mesocosms where all dung pats were treated) but emergence rates increased with TST level, reaching 68–88 % emergence where no dung pats were treated with ivermectin. Ivermectin-induced mortality occurred predominantly at egg and first instar stages. TST can provide refuges for dung beetles offering a strategy for livestock producers to maintain livestock welfare whilst benefiting from ecosystem services provided by important insects.

Characterisation of Nematoda and Digenea in selected Australian freshwater snails

Freshwater snails are integral to local ecosystems as a primary food source for various vertebrate species, thereby contributing significantly to ecological food webs. However, their role as intermediate hosts also makes them pivotal in the transmission of parasites. In Australia, research on freshwater snails has predominantly focused on their role as intermediate hosts for livestock parasites, while there has been limited exploration of the impact of these parasites on snail health and population dynamics. The aim of this study was to determine parasitic infection in freshwater snails. This study was conducted in the south-eastern region of Australia, in 2022. A total of 163 freshwater snails from four different species were collected and examined in the Murrumbidgee catchment area in the southeastern part of Australia during the Southern Hemisphere summer and autumn months (February to May). The species included Isidorella hainesii, Glyptophysa novaehollandica, Bullastra lessoni (endemic species), and Physella acuta (an introduced species). Through the analysis of sequence data from the various regions of the nuclear ribosomal DNA, we determined that the Digenea species in this study belonged to three distinct species, including Choanocotyle hobbsi, Petasiger sp. and an unidentified species belonging to Plagiorchioidea. Additionally, analysis of the sequences from Nematoda found in this study, revealed they could be categorized into two separate taxa, including Krefftascaris sp. and an unidentified nematode closely associated with plant and soil nematodes. This research holds significant implications for the future understanding and conservation of Australian freshwater ecosystems. Most parasites found in the present study complete their life cycle in snails and turtles. As many of freshwater snail and turtle species in Australia are endemic and face population threats, exploring the potential adverse impacts of parasitic infections on snail and turtle health, is crucial for advancing our understanding of these ecosystems and also paving the way for future research and conservation efforts. While none of the native snail species in the present study have been listed as endangered or threatened, this may simply be attributed to the absence of regular population surveys.

Experimental Infections Reveal Acquired Zoonotic Capacity of Human Schistosomiasis Trough Hybridization.

We are currently witnessing the endemization of urogenital schistosomiasis in southern Europe. The incriminated parasite is a hybrid between a human parasite and a livestock parasite. Using an experimental evolutionary protocol, we created hybrid lines from pure strains of both parasite species. We showed that the host spectrum of the human parasite is enlarged to the livestock parasite after genomic introgression. We also evidenced that the tropism of the parasites within the host changes and that some hybrid lines are more virulent than the parental strains. These results engage a paradigm shift from human to zoonotic transmission of urogenital schistosomiasis.

A phenotypic screen of the Global Health Priority Box identifies an insecticide with anthelmintic activity

BackgroundInfection with parasitic nematodes (helminths), particularly those of the order Strongylida (such as Haemonchus contortus), can cause significant and burdensome diseases in humans and animals. Widespread drug (anthelmintic) resistance in livestock parasites, the absence of vaccines against most of these nematodes, and a lack of new and effective chemical entities on the commercial market demands the discovery of new anthelmintics. In the present study, we searched the Global Health Priority Box (Medicines for Malaria Venture) for new candidates for anthelmintic development.MethodsWe employed a whole-organism, motility-based phenotypic screening assay to identify compounds from the Global Health Priority Box with activity against larvae of the model parasite H. contortus, and the free-living comparator nematode Caenorhabditis elegans. Hit compounds were further validated via dose–response assays, with lead candidates then assessed for nematocidal activity against H. contortus adult worms, and additionally, for cytotoxic and mitotoxic effects on human hepatoma (HepG2) cells.ResultsThe primary screen against H. contortus and C. elegans revealed or reidentified 16 hit compounds; further validation established MMV1794206, otherwise known as ‘flufenerim’, as a significant inhibitor of H. contortus larval motility (half-maximal inhibitory concentration [IC50] = 18 μM) and development (IC50 = 1.2 μM), H. contortus adult female motility (100% after 12 h of incubation) and C. elegans larval motility (IC50 = 0.22 μM). Further testing on a mammalian cell line (human hepatoma HepG2 cells), however, identified flufenerim to be both cytotoxic (half-maximal cytotoxic concentration [CC50] < 0.7 μM) and mitotoxic (half-maximal mitotoxic concentration [MC50] < 0.7 μM).ConclusionsThe in vitro efficacy of MMV1794206 against the most pathogenic stages of H. contortus, as well as the free-living C. elegans, suggests the potential for development as a broad-spectrum anthelmintic compound; however, the high toxicity towards mammalian cells presents a significant hindrance. Further work should seek to establish the protein–drug interactions of MMV1794206 in a nematode model, to unravel the mechanism of action, in addition to an advanced structure–activity relationship investigation to optimise anthelmintic activity and eliminate mammalian cell toxicity.Graphical

Does Faeces Excreted by Moxidectin-Treated Sheep Impact Coprophagous Insects and the Activity of Soil Microbiota in Subtropical Pastures?

Moxidectin (MOX) is used to control helminth parasites in ruminant livestock. It is released through feces and remains in the environment for a long period. This study aimed to evaluate the impact of faeces excreted by moxidectin-treated sheep on soil biodiversity (coprophagous insects, soil microbial biomass, and activity) to establish environment-related guidelines regarding the use of MOX in sheep livestock. The study consisted of two experiments. In the first one, faeces from MOX-treated (subcutaneous dose of 0.2 mg·kg-1 body weight) and nontreated rams were placed on an animal-free pasture field, protected or not against rain, for 88 days. Then, coprophagous insects were captured, identified, and counted, and faeces degradation was evaluated by measuring dry weight and carbon (C) and nitrogen (N) contents over time. Diptera, Hymenoptera, Isoptera, and Coleoptera were equally encountered in faeces from MOX-treated and nontreated animals. Faecal boluses of MOX-treated animals (with higher N content) not protected against rain degraded faster than faecal boluses of nontreated animals (with lower N content). In the second experiment, faeces from nontreated animals were amended with increasing amounts of MOX (75 to 3,000 ng·kg-1 faeces), mixed with soil samples from animal-free pasture (1.9 to 75 ng·kg-1 soil), and incubated in a greenhouse for 28 days. Increasing concentrations of MOX did not prevent the growth of cultivable bacteria, actinobacteria, or fungi in culture media. However, even the lower MOX concentration (1.9 ng·kg-1 soil) abruptly decreased soil microbial biomass, basal respiration, and N mineralization. Thus, the results indicate that faeces excreted from sheep treated with MOX under the experimental conditions of this study are not harmful to the coprophagous insects. However, adding MOX to faeces from drug-free sheep had a negative impact on soil microbial activity and biomass.

Prevalence of Gastrointestinal Tract Parasites in Small Ruminants in and around Jaja Town, Melka Belo Woreda Of East Haraghe Zone, Oromia, Ethiopia

INTRODUCTION: Parasitic diseases are global problem and effects are more pronounced, in Sub-Saharan Africa in general and Ethiopia in particular due to the availability of a wide range of agro-ecological factors suitable for diversified hosts and parasite species. Common abdominal parasites of livestock are coccidia species of phylum protozoa. Trematodes belong to flukes, nematodes commonly called roundworms, cestodes famous on tapeworms. METHODS: A cross-sectional study was carried out from May, 2023 to August, 2023 to determine the prevalence and to identify gastrointestinal tract parasites from fecal samples collected from goats and sheep in and around Jaja town and to identify the parasitic fauna circulating in the study area. RESULTS: In the present study a total 384 small ruminants (322 goats and 62 sheep) were examined for prevalence of gastrointestinal tract parasites coprological examination there was an overall prevalence of 81.51% (313/384). The gastrointestinal tract parasites infection was more prevailing in female (83.41%) than male (78.71%) in case of sex, in adult (83%) than young (78.83%) in case of age, in sheep (85.5%) than goats (80.75%) in case of species, Statistically significant difference were recorded (OR=1.85231, CI=1.204293-2.849005, P=0.005) between body conditions and the prevalence of gastrointestinal tract parasite infection and Dhagaya Belo (97.5%) followed by Makanisa (88.75%), Jaja Town (79.9), Ifabas (77.5%) and Tokuma Jalala (70%) in case of Address. CONCLUSIONS: In the study area indicates gastrointestinal tract parasites the most impairments of small ruminants. Statistically there were no significance difference between address, species, sex, age and the prevalence of gastrointestinal tract parasite infection. The majority of small ruminants were infected with one, two or three genera of the same or different gastrointestinal tract parasites.

Anti-parasitic activities of four synthetic chemicals anthelmintics on Haemonchus contortus

Synthetic anthelmintic (AHs) have always been used in veterinary medicine. The increasing development of resistance to these AHs in livestock parasites threatens animal health and global production, calling into question their effectiveness. In vitro egg hatch inhibition assay (EHA) and larval development test (LDT) performed showed ovicidal and larvicidal activities of four AHs compared to the control (PBS). However, a suspicion of Haemonchus contortus resistance to Bolumisole M1 (IC50 = 0.122µg/mL) and Ivomec-D (IC50 = 0.130µg/mL) was recorded after the EHA. Similarly, resistance was observed to Bolumisole M1 (IC50 = 0.024µg/mL), Ivomec-D (IC50 = 0.07µg/mL) and Kelanthic (IC50 = 0.144µg / mL) following the LDT. These results show that cases of parasite resistance to AHs exist in small ruminants in Burkina Faso. Therefore, a reasoned use of AHs could be a good approach in the control of gastrointestinal nematodes of small ruminants in Burkina Faso. Subsequent in vivo studies should be conducted to confirm this resistance in the real conditions of these ruminants.

Plasma disposition and faecal excretion of eprinomectin following subcutaneous administration in Saanen and Alpine goats

Eprinomectin is extensively used in veterinary medicine, particularly in the treatment of internal and external parasites in livestock, including goats. The pharmacokinetic behavior of eprinomectin in plasma and faeces was studied after a single subcutaneous administration in two different goat breeds at a dose of 0.2 mg/kg body weight. The study was conducted on one-year-old female Saanen (n = 8) and Alpine (n = 8) goats in a parallel design. There were no significant differences between Saanen and Alpine goats on the peak plasma concentration (Cmax, 28.59 ± 7.46 ng/mL vs. 37.69 ± 14.89 ng/mL), area under the curve (AUC0-∞, 93.08 ± 11.66 ng.d/mL vs. 116.98 ± 48.36 ng.d/mL), area under the first moment curve (AUMC0-∞, 311.05 ± 67.23 ng.d2/mL vs. 348.25 ± 202.64 ng.d2/mL) and mean residence time (MRT, 3.24 ± 0.77 d vs. 2.74 ± 0.64 d) values. The plasma terminal half-life and the time to reach peak plasma concentration were significantly higher in Saanen goats (T1/2λz, 2.18 ± 0.43 d; Tmax, 1.21 ± 0.25 d) than in Alpine goats (T1/2λz, 1.66 ± 0.41 d; Tmax, 0.79 ± 0.25 d). The results revealed that the plasma concentration of eprinomectin did not differ depending on the breed in Saanen and Alpine goats. However, it was determined that the eprinomectin clearance from the body may vary depending on the breed in goats. The faecal eprinomectin concentration of Saanen and Alpine goats was 90 and 80 times higher than the plasma eprinomectin concentration, respectively. Although high faecal excretion of eprinomectin confers a high efficacy advantage against parasites in the gastrointestinal tract, it may pose an ecotoxicological risk to manure fauna and aquatic organisms with high susceptibility to this compound.

Bovine Piroplasma Populations in the Philippines Characterized Using Targeted Amplicon Deep Sequencing.

Molecular assays and capillary electrophoresis sequencing have been used to identify parasites in livestock. The low sample capacity, which increases labor and processing time, is one drawback. Targeted amplicon sequencing (Ampliseq) uses the fast and large sample capacity platform to identify parasites in the target host, overcoming this limitation. DNA was extracted from 162 whole blood samples collected from cattle in three provinces in the Philippines. Using Illumina's Miseq platform, the V4 hypervariable region of the piroplasma 18S rRNA gene was amplified and sequenced. The AMPtk pipeline was used to obtain distinct amplicon sequence variants (ASVs) and the NCBI BLAST non-redundant database was used to assign taxonomy. In total, 95 (58.64%) samples were positive for piroplasma. Using the AMPTk pipeline, 2179 ASVs were obtained. A total of 79 distinct ASVs were obtained after clustering and filtering, which belonged to genera Babesia (n = 58), Theileria (n = 17), Hepatozoon (n = 2), and Sarcocystis (n = 2). The ASV top hits were composed of 10 species: Babesia bovis, B. bigemina, Theileria orientalis, Babesia sp., Hepatozoon canis, Sarcocystis cruzi, T. annulata, T. equi, T. mutans, and Theileria sp. Thung Song. The results generated in this study demonstrated the applicability of Ampliseq in detecting piroplasmid parasites infecting cattle in the Philippines.

Fasciola hepatica antioxidant and protease-inhibitor cocktail recombinant vaccines administered five times elicit potent and sustained immune responses in sheep but do not confer protection

Our laboratory’s vaccine development strategy against the livestock parasite Fasciola hepatica centres around disrupting key biological processes by combining groups of antigens with similar/complementary functional actions into a single vaccine cocktail. In this study the focus was on antioxidant protein vaccines and a protease inhibitor vaccine aimed at disrupting the parasite’s ability to defend against oxidative stress and protease-inhibitor balance, respectively. Two combinations of recombinantly expressed antioxidants were assessed, namely peroxiredoxin (rFhPrx), thioredoxin (rFhTrx) and thioredoxin-glutathione reductase (rFhTGR) (Group 1) and rFhPrx, rFhTrx, and two superoxide dismutases (rFhSOD1 and rFhSOD3) (Group 2). The protease inhibitor vaccine cocktail included representatives of each of the key secreted protease inhibitor families, namely a Kunitz-type inhibitor (rFhKT1), a serpin (rFhSrp1) and a stefin, (rFhStf1) (Group 3). The vaccine combinations were formulated in adjuvant Montanide 61VG administered at five timepoints; two before experimental challenge with 60 F. hepatica metacercariae and three after infection. The vaccine combinations did not reduce the liver fluke burden, and only Group 2 displayed a marginal reduction in egg viability (8.2%). Despite previous results showing an effect of liver fluke vaccines on overall weight gain in infected animals, no significant (P value >0.05) impact on weight gain was observed in this study. Antibodies were elicited against all the vaccine antigens within the cocktails and were maintained at high levels to the end of the trial, due to our strategy of continuing vaccine administration after infection. However, these responses were not boosted by the challenge F. hepatica infection. A comparative analysis with previous vaccine data using a protease inhibitor vaccine found no repeat of the promising outcomes associated with this vaccine, indicating that the addition of rFhSrp1 to the vaccine cocktail did not improve vaccine efficacy. Assessment of liver pathology across the two trials using a modified liver enzyme score (glutamate dehydrogenase to platelet ratio) at eight weeks post infection suggests an association with liver fluke burden above 45 flukes, which could be used to predict liver pathology in future trials. The results reported in this study highlight the ambiguousness in liver fluke vaccine development and the difficulty in obtaining consistent and repeatable protection. This work stresses the need for repetition of trials and the use of sufficiently sized groups to assess vaccine efficacy with adequate statistical power.

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

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

Exploitation of Host Resistance: A Promising Alternative Approach to Control Gastrointestinal Nematodoses in Small Ruminant: A Review

Gastrointestinal nematodes (GINs) are the most insidious pathogens causing severe economic losses to the livestock industry. Among GINs Haemonchus contortus is the most pathogenic and predominant parasite of small ruminant livestock. Although the use of chemical anthelmintics is still the corner-stone of control method for GINs, the increasing rate of prevalence of anthelmintic resistance has made it less reliable control option. Anthelmintic resistance together with global demands for chemical residue free animal product has led to search for alternative sustainable control strategies which rely less on chemical anthelmintics. One of such strategy is the exploitation of host resistance against the GINs including H. contortus. The resistance of animals to GINs varies within and between breeds of sheep and goats. Host immune response plays an important role in host resistance but the immune mechanisms responsible for resistance are not fully known. Studies on identification of gene/(s) responsible for host resistance are also being carried out to find out the molecular mechanism of GINs resistance in sheep and goats all over the world. Selective breeding for GINs resistance is the ultimate solution for the problems of anthelmintic resistance. This article reviews the published reports on GINs resistance in relation to immunological response and genetic studies in small ruminants and discusses the prospects for selective breeding of GINs resistance in sheep and goat.

UPDATE ON THE IVERMECTIN’ MODE OF ACTION AND RESISTANCE MECHANISMS: A GENERAL MEDICAL LITERATURE OVERVIEW

Ivermectin (IVM) is an antiparasitic drug, and it belongs to the avermectin family ofmedications. After its discovery in 1975, its first uses were in veterinary medicine toprevent and treat heartworm and acariasis. Approved for human use in 1987, today it isused to treat infestations including head lice, scabies, river blindness (onchocerciasis),strongyloidiasis, trichuriasis, ascariasis and lymphatic filariasis. It works through manymechanisms to kill the targeted parasites, and can be taken orally, or applied to the skinfor external infestations. It is on the World Health Organization's List of EssentialMedicines, it is available as a generic medicine, and is approved by the U.S. Food andDrug Administration as an antiparasitic agent. By the year 2022, it was the 420th mostcommonly prescribed medication in the United States, with more than 100,000prescriptions.The pioneering drug IVM, a dihydro derivative of avermectin originating solely froma single microorganism isolated at the Kitasato Intitute, Tokyo, Japan from Japanese soilhas had an immeasurably beneficial impact in improving the lives and welfare of billionsof people throughout the world. Originally introduced as a veterinary drug, it kills a widerange of internal and external parasites in commercial livestock and companion animals. Itwas quickly discovered to be ideal in combating two of the world’s most devastating anddisfiguring diseases which have plagued the world’s poor throughout the tropics forcenturies. It is now being used free-of-charge as the sole tool in campaigns to eliminateboth diseases globally. It has also been used to successfully overcome several other humandiseases and new uses for it are continually being found.IVM with many global trade names of Stromectol®, Soolantra®, Sklice® or Vietnamtrade names of Stromectin®, Pizar®, A.T Ivermectine®. IVM can be use in oral or topicalroute administration by ATC code D11AX22 (WHO) , P02CF01 (WHO), QP54AA01(WHO), QS02QA03 (WHO).

A Study on Prevalence, Morphology and Morphometric of Gongylonema pulchrum in Sheep Slaughtered in Sari, Northern Iran

Background and Aims: The genus Gongylonema infects the upper digestive tract of birds, mammals, and humans. Livestock parasites, especially in the gastrointestinal tract, have caused irreparable damage, including death, reduced products, and economic losses. The present study aimed to reveal the prevalence and morphological and morphometric study of Gongylonema spp. isolated from the esophagus of slaughtered sheep in Sari, northern Iran.&#x0D; Materials and Methods: Esophagi of 340 sheep were collected from Sari's industrial slaughterhouse during the summer and autumn of 2021 (summer=115, autumn= 225). After longitudinal cutting, the surfaces of the esophageal mucosa were carefully checked under the light. The prevalence of infection was estimated, and the morphometric and morphological characteristics of the isolated worms were investigated using a calibrated light microscope and camera lucida.&#x0D; Results: The prevalence of infection was 7.6% (26 isolates), which was estimated for summer and autumn 12 out of 115 (10.4%) and 14 out of 225 (6.2%), respectively. A comparison of morphological features of nematodes in this study with Gongylonema morphological criteria showed that all of them were Gongylonema pulchrum.&#x0D; Conclusions: In the present study, a moderate gongylonemiasis infection was estimated in the sheep from Sari's industrial slaughterhouse. Morphological examination of the retrieved worms showed characteristic morphologies of Gongylonema pulchrum. To clarify the status of the infection, several morphological and molecular studies should be performed on different types of intermediate and final hosts of the parasite in different parts of the country.

Macrocyclic lactone residues in cattle dung result in a sharp decline in the population of dung beetles in the rangelands of northern China

Dung beetles perform important ecosystem functions including livestock dung removal, nutrient recycling and parasite control. However, more research is being done on the effects of veterinary drug residues on dung beetles due to the widespread usage of macrocyclic lactone (ML). While a number of research on this topic have been published in Europe, Africa and America, few have been in Asia. In the past decade, standard veterinary antibiotics administration in livestock grazing systems in the rangelands of northern China has included ML. In the present study, the abundance, species richness, diversity, and evenness of dung beetles in the rangelands of northern China in 2020 were examined and compared to the reference data from 2010, when parasiticide had never been used, to better understand the changes in dung beetle communities after the long-term use of parasiticides. The abundance and diversity of dung beetle populations in the current three rangelands in northern China were first investigated using a baited-trap experiment. The findings revealed a 67.3 % decrease in dung beetle abundance and a shift in the dominant species from Aphodiidae to Staphylinidae. Cattle dung on the three studied rangelands included high ML residues ranging from 22.7 ppb to 130.1 ppb. According to the results of the correlation analysis, the beetle abundance and ML residues in cattle dung were negatively correlated. In the meantime, the findings of a field examination of undecomposed cattle dung on 34 rangelands in northern China revealed that the coverage rate of dried cattle dung pats ranged from 2 % to 6 % on 24 rangelands and reached above 10 % on four rangelands. According to the current findings, the decrease in cattle dung beetles would slow down the decomposition of cattle dung pats and decrease the available grazing area. Therefore, the dung beetle community in the rangelands of northern China would be negatively impacted by the frequent administration of ML to cattle. This would result in significant changes to the biogeochemical cycle of rangeland and had a negative impact on the development of local husbandry. During rangeland management, more attention should be given to the dynamic changes of coprovorous insects and the application of veterinary antibiotics.