Gastrointestinal anthelmintic plants used on small ruminants in Benin: Traditional use and scientific results - Review.

In Benin, livestock breeders frequently use medicinal plants to treat gastrointestinal diseases in small ruminants. The aim of this review is to list the plants traditionally used in this context and to present the scientific findings on the efficacy of these plants. An extensive search was carried out using PubMed, Scopus, ScienceDirect, Biomed Central and Google Scholar databases to collect data, with combinations of relevant french and english keywords such as "ethnobotanical survey", "anthelmintic properties", "medicinal plants", "gastrointestinal parasites", "digestive strongyles", "Haemonchus", "Trichostrongylus", "small ruminants", "sheep", "goats" and "Benin". A total of 45 published articles met the eligibility criteria. This review listed 123 plants used by breeders to treat gastrointestinal ailments in small ruminants. The most commonly used parts are leaves and barks, and the most common forms are decoction, maceration and powder. Scientific studies have demonstrated the anthelmintic properties of 18 plants, including Zanthoxylum zanthoxyloides, Newbouldia laevis, Mitragyna inermis and Combretum glutinosum. The powders or leaf extracts of these plants showed in vivo significant reductions of over 50% in egg excretion, larval establishment, viability and fertility of gastrointestinal strongyles in small ruminants. Extracts of these plants also revealed in vitro inhibitory activity of over 50% on egg hatching, larval migration and motility of gastrointestinal strongyles. This manuscript highlights the traditional use of anthelmintic plants in small ruminants in Benin and provides scientific results supporting the efficacy of these plants.

Identification of third stage larvae of strongyles and molecular diagnosis of Strongylus vulgaris in the feces of Thoroughbred horses kept in training centers in Rio de Janeiro, Brazil.

The aims of the present study were to identify strongyles in the feces of Thoroughbred horses based on larval morphology; to detect Strongylus vulgaris using molecular diagnosis and compare results to those of feces culture; and to determine the association between the presence of S. vulgaris with corresponding animal information (age range, gender, and anthelmintic use). Feces of horses kept in six Training Centers in Rio de Janeiro State, that showed the presence of ≥500 eggs per gram of feces (EPG) were subjected to strongyle identification. Of the 520 fecal samples collected, 35 had an EPG ≥ 500. After fecal culture for L3 larvae identification, DNA was extracted, subjected to PCR to amplify the ITS2 region DNA fragment of S. vulgaris, and sequenced. A total of 3500 larvae were analyzed. Most were classified as small strong (99.7%), with an emphasis on the type A subfamily of Cyathostominae. Forms of S. vulgaris only corresponded to 0.2%. In all, 25 samples showed amplified S. vulgaris DNA products and 11 showed nucleotide sequences with high sequence identity. Fecal culture and PCR results showed poor agreement (kappa = 0.105) for S. vulgaris diagnosis. Age, gender, anthelmintic use, and anthelmintic administration interval were not statistically significant. The present study showed the presence of S. vulgaris in the feces of horses kept in Rio de Janeiro Training Centers, mainly seen via PCR, which has emerged as the most effective tool for diagnosis. This study made it possible to identify strongyles that infect horses in the region, emphasizing upon the necessity for constant monitoring of the animals.

Endemic status of urogenital schistosomiasis and the efficacy of a single-dose praziquantel treatment in unmapped rural farming communities in Oyo East Local Government Area, Oyo State, Nigeria.

BACKGROUND: Schistosomiasis is endemic in Nigeria, and the treatment is largely concentrated on children enrolled in schools. Consequently, the coverage of non-enrolled school-aged children is often neglected. Ajagba and Awosan are two communities in Nigeria that have never had any control intervention. Hence, this survey was designed to determine the endemicity of urogenital schistosomiasis and to evaluate the efficacy of a single-dose praziquantel in the communities. METHODS: Urine sample (10 mL) of each participant from Ajagba and Awosan communities was filtered through 12µm polycarbonate filter. The filter was placed on a microscope slide, and stained with a drop of 1% Lugol iodine solution. The stained slides were examined under the microscope and the numbers of S. haematobium eggs were counted. Water contact sites were searched for snail hosts and the snails collected were shed for Schistosoma cercariae. Data were analyzed using SPSS version 24.0 and the significance level was set at 95%. RESULTS: The overall prevalence of infection in the Ajagba community was 45.6% with a mean intensity of 61.1 ± 144.5 eggs/10 mL of urine, while the prevalence of infection in the Awosan community was 5.7% with a mean intensity of 1.4 ± 6.8 eggs/10 mL of urine. The school-aged children had a prevalence and mean intensity of infection of 73.1% and 111.6 ± 177.9 eggs/10 mL of urine, respectively. Following treatment, women had a higher egg reduction rate than men (p = 0.0283). Bulinus globosus were found in Ajagba but not in Awosan, with 5.7% shedding Schistosoma spp, cercariae. CONCLUSION: Urogenital schistosomiasis was hyperendemic in the Ajagba community, and hypoendemic in the Awosan community. The presence of Bulinus globosus supported the transmission of the schistosomiasis in the Ajagba community. Communities where schistosomiasis is still actively transmitted in Nigeria should be identified for effective intervention through the MDA programs.

Impact of Strongyloides stercoralis infection on complement activation in Type 2 diabetes mellitus: Insights from a clinical and anthelmintic intervention study.

BACKGROUND: Numerous studies indicate a potential protective role of helminths in diabetes mellitus (DM) progression. The complement system, vital for host defense, plays a crucial role in tissue homeostasis and immune surveillance. Dysregulated complement activation is implicated in diabetic complications. We aimed to investigate the influence of the helminth, Strongyloides stercoralis (Ss) on complement activation in individuals with type 2 DM (T2D). METHODOLOGY: We assessed circulating levels of complement proteins (C1q, C2, C3, C4, C4b, C5, C5a, and MBL (Lectin)) and their regulatory components (Factor B, Factor D, Factor H, and Factor I) in individuals with T2D with (n = 60) or without concomitant Ss infection (n = 58). Additionally, we evaluated the impact of anthelmintic therapy on these parameters after 6 months in Ss-infected individuals (n = 60). RESULTS: Ss+DM+ individuals demonstrated reduced levels of complement proteins (C1q, C4b, MBL (Lectin), C3, C5a, and C3b/iC3b) and complement regulatory proteins (Factor B and Factor D) compared to Ss-DM+ individuals. Following anthelmintic therapy, there was a partial reversal of these levels in Ss+DM+ individuals. CONCLUSION: Our findings indicate that Ss infection reduces complement activation, potentially mitigating inflammatory processes in individuals with T2D. The study underscores the complex interplay between helminth infections, complement regulation, and diabetes mellitus, offering insights into potential therapeutic avenues.

New benzimidazole derivative compounds with in vitro fasciolicidal properties.

BACKGROUND: Control of the zoonotic food-borne parasite Fasciola hepatica remains a major challenge in humans and livestock. It is estimated that annual economic losses due to fasciolosis can reach US$3.2 billion in agriculture and livestock. Moreover, the wide distribution of drug-resistant parasite populations and the absence of a vaccine threaten sustainable control, reinforcing the need for novel flukicides. METHODS: The present work analyses the flukicidal activity of a total of 70 benzimidazole derivatives on different stages of F. hepatica. With the aim to select the most potent ones, and screenings were first performed on eggs at decreasing concentrations ranging from 50 to 5 µM and then on adult worms at 10 µM. Only the most effective compounds were also evaluated using a resistant isolate of the parasite. RESULTS: After the first screenings at 50 and 10 µM, four hit compounds (BZD31, BZD46, BZD56, and BZD59) were selected and progressed to the next assays. At 5 µM, all hit compounds showed ovicidal activities higher than 71% on the susceptible isolate, but only BZD31 remained considerably active (53%) when they were tested on an albendazol-resistant isolate, even with values superior to the reference drug, albendazole sulfoxide. On the other hand, BZD59 displayed a high motility inhibition when tested on adult worms from an albendazole-resistant isolate after 72 h of incubation. CONCLUSIONS: BZD31 and BZD59 compounds could be promising candidates for the development of fasciolicidal compounds or as starting point for the new synthesis of structure-related compounds.

Intestinal cell diversity and treatment responses in a parasitic nematode at single cell resolution.

BACKGROUND: Parasitic nematodes, significant pathogens for humans, animals, and plants, depend on diverse organ systems for intra-host survival. Understanding the cellular diversity and molecular variations underlying these functions holds promise for developing novel therapeutics, with specific emphasis on the neuromuscular system's functional diversity. The nematode intestine, crucial for anthelmintic therapies, exhibits diverse cellular phenotypes, and unraveling this diversity at the single-cell level is essential for advancing knowledge in anthelmintic research across various organ systems. RESULTS: Here, using novel single-cell transcriptomics datasets, we delineate cellular diversity within the intestine of adult female Ascaris suum, a parasitic nematode species that infects animals and people. Gene transcripts expressed in individual nuclei of untreated intestinal cells resolved three phenotypic clusters, while lower stringency resolved additional subclusters and more potential diversity. Clusters 1 and 3 phenotypes displayed variable congruence with scRNA phenotypes of C. elegans intestinal cells, whereas the A. suum cluster 2 phenotype was markedly unique. Distinct functional pathway enrichment characterized each A. suum intestinal cell cluster. Cluster 2 was distinctly enriched for Clade III-associated genes, suggesting it evolved within clade III nematodes. Clusters also demonstrated differential transcriptional responsiveness to nematode intestinal toxic treatments, with Cluster 2 displaying the least responses to short-term intra-pseudocoelomic nematode intestinal toxin treatments. CONCLUSIONS: This investigation presents advances in knowledge related to biological differences among major cell populations of adult A. suum intestinal cells. For the first time, diverse nematode intestinal cell populations were characterized, and associated biological markers of these cells were identified to support tracking of constituent cells under experimental conditions. These advances will promote better understanding of this and other parasitic nematodes of global importance, and will help to guide future anthelmintic treatments.

Improving the Cost-efficiency of Preventive Chemotherapy: Impact of New Diagnostics on Stopping Decisions for Control of Schistosomiasis.

BACKGROUND: Control of schistosomiasis (SCH) relies on the regular distribution of preventive chemotherapy (PC) over many years. For the sake of sustainable SCH control, a decision must be made at some stage to scale down or stop PC. These "stopping decisions" are based on population surveys that assess whether infection levels are sufficiently low. However, the limited sensitivity of the currently used diagnostic (Kato-Katz [KK]) to detect low-intensity infections is a concern. Therefore, the use of new, more sensitive, molecular diagnostics has been proposed. METHODS: Through statistical analysis of Schistosoma mansoni egg counts collected from Burundi and a simulation study using an established transmission model for schistosomiasis, we investigated the extent to which more sensitive diagnostics can improve decision making regarding stopping or continuing PC for the control of S. mansoni. RESULTS: We found that KK-based strategies perform reasonably well for determining when to stop PC at a local scale. Use of more sensitive diagnostics leads to a marginally improved health impact (person-years lived with heavy infection) and comes at a cost of continuing PC for longer (up to around 3 years), unless the decision threshold for stopping PC is adapted upward. However, if this threshold is set too high, PC may be stopped prematurely, resulting in a rebound of infection levels and disease burden (+45% person-years of heavy infection). CONCLUSIONS: We conclude that the potential value of more sensitive diagnostics lies more in the reduction of survey-related costs than in the direct health impact of improved parasite control.

How Does Treatment Coverage and Proportion Never Treated Influence the Success of Schistosoma mansoni Elimination as a Public Health Problem by 2030?

BACKGROUND: The 2030 target for schistosomiasis is elimination as a public health problem (EPHP), achieved when the prevalence of heavy-intensity infection among school-aged children (SAC) reduces to <1%. To achieve this, the new World Health Organization guidelines recommend a broader target of population to include pre-SAC and adults. However, the probability of achieving EPHP should be expected to depend on patterns in repeated uptake of mass drug administration by individuals. METHODS: We employed 2 individual-based stochastic models to evaluate the impact of school-based and community-wide treatment and calculated the number of rounds required to achieve EPHP for Schistosoma mansoni by considering various levels of the population never treated (NT). We also considered 2 age-intensity profiles, corresponding to a low and high burden of infection in adults. RESULTS: The number of rounds needed to achieve this target depends on the baseline prevalence and the coverage used. For low- and moderate-transmission areas, EPHP can be achieved within 7 years if NT ≤10% and NT <5%, respectively. In high-transmission areas, community-wide treatment with NT <1% is required to achieve EPHP. CONCLUSIONS: The higher the intensity of transmission, and the lower the treatment coverage, the lower the acceptable value of NT becomes. Using more efficacious treatment regimens would permit NT values to be marginally higher. A balance between target treatment coverage and NT values may be an adequate treatment strategy depending on the epidemiological setting, but striving to increase coverage and/or minimize NT can shorten program duration.

The effectiveness of albendazole against hookworm infections and the impact of bi-annual treatment on anaemia and body mass index of school children in the Kpandai district of northern Ghana.

The impact of the Global Programme to Eliminate Lymphatic Filariasis (GPELF) (initiated in 2000 in Ghana and ran for 12 years) in mitigating soil-transmitted helminth (STH) infections in LF-endemic areas is unknown. During a 1-year hiatus which ensued between 2011 and 2012, a longitudinal study was conducted to determine GPELF effect on hookworm infections in selected communities involved in the programme since its inception, while measuring the effectiveness of biannual ALB treatments on schoolchildren living in such communities. A total of 399 school children aged 3 to 18 years were randomly selected from four communities in the Kpandai district of northern Ghana. Each presented a single stool sample at baseline, 21 days post-treatment, at the 3rd and 6th months, 21 days post-second intervention (i.e. following sample collection and treatment with ALB in the 6th month), and in the ninth month of the study period. Haemoglobin (hb) levels were also measured at all time points using finger prick blood samples and a URIT digital test kit. Each participant submitting a sample, was treated with a single-dose ALB (400mg) at baseline and in the sixth month. Stool samples were processed by preparing duplicate Kato-Katz slides per sample, and examined by microscopy. The Body Mass Index-for-age z-scores (BAZ) of participants were assessed following the determination of BMIs at each time point by measuring their height and weight with a stadiometer and weighing scale. Overall hookworm prevalences were 25.68% (95% CI = 20.51-31.75) at baseline, 11.18% (95% CI = 7.87-15.41) 21 days post-treatment, 11.78% (95% CI = 8.38-16.11) and 6.95% (95% CI = 4.41-10.43) in the 3rd and 6th months, 0.91% (95% CI = 0.19-2.65) 21 days post-second intervention, and 8.46% (95% CI = 5.62-12.23) in the ninth month. Observed overall faecal egg count reduction rates (ERRs) were 94.21% (95% CI = 81.50%- 100.00%) 21 days after baseline treatment, 97.70% (95% CI = 85.08-100.00) and 96.95% (95% CI = 84.18%- 100.00%) in the 3rd and 6th months, 99.98% (95% CI = 86.42%- 100.00%) 21 days post-second intervention, and 17.18% (95% CI = 14.07%- 20.67%) in the 9th month. Respective cure rates (CRs) were 62.35% (95% CI = 46.71-81.56%), 85.88% (95% CI = 67.32-100.00%), 87.06% (95% CI = 68.36%- 100.00%), 98.82% (95% CI = 78.83%- 100.00%), and 36.36% (95% CI = 9.91%- 93.11%). Additionally, increases in the percent frequency of 'normal hb' (p < 0.01) were observed across the study time points, whilst 'normal BAZ' cases remained high (from 94.87% to 98.87%) throughout the study period. These findings primarily indicate satisfactory effectiveness of ALB which may be maintainable in mass drug administration programmes by the modification of treatment strategies from annual to bi-annual regimes. This could minimize the likelihood of emerging poorly-responding hookworm phenotypes in Ghana. Additionally, a positive impact of bi-annual treatment on participant anaemia status is herein indicated with particular regard to the school children in our cohort.

PHARMACOKINETICS AND EFFICACY OF A SINGLE TOPICAL DOSE OF EPRINOMECTIN IN GIRAFFE (GIRAFFA SPP.).

Growing resistance to current antiparasitic medications, both in livestock and in zoological species under human care, makes it imperative to evaluate available drugs on the market, such as eprinomectin. In this prospective study, five males and one female of reticulated (Giraffa reticulata; n = 2), Masai (Giraffa tippelskirchii; n = 1), Nubian (Giraffa camelopardalis; n = 2), and hybrid subspecies (n = 1) of giraffe, received 1.5 mg/kg eprinomectin topically along the dorsum. Using high-performance liquid chromatography, concentrations of eprinomectin in plasma samples collected at 0, 4, 24, and 48 h, and 7, 14, 21, and 28 d were evaluated following drug administration. Complete blood cell counts and biochemistry panels were performed before (n = 6) and after (n = 3) eprinomectin administration. Samples for modified double centrifugal fecal flotation (n = 6) were evaluated prior to eprinomectin administration to evaluate for endoparasites and were repeated after the study (n = 5). Noncompartmental pharmacokinetic analysis was applied to the data. The observed maximum plasma concentration was 11.45 ng/ml and the time of observed maximum concentration was 2.67 d. The mean terminal half-life was 5.16 d. No adverse effects were observed related to eprinomectin administration and no blood work changes were observed. Parasite loads decreased (n = 3) or did not change (n = 2) after eprinomectin administration. The mean peak plasma concentration of eprinomectin in giraffe was similar to that achieved in cattle, despite using three times the dose.

Follicular larva migrans.

Follicular larva migrans (FLM) is a rare and atypical clinical presentation of hookworm-related cutaneous larva migrans (HrCLM). FLM is characterized clinically by follicular, round, small, erythematous papules that are sometimes topped by vesicles or pustules. These lesions are usually located on the abdomen, back, buttocks and thighs and are accompanied by more or less severe pruritus. Some typical and/or short and fragmented tracks may also be visible. FLM is more resistant to anti-helminthic drugs than classical HrCLM: this is likely due to the deep location of larvae in hair follicles. We present two cases of FLM and a review of the literature.

Efficacy of a Single Oral Dose of Artesunate plus Sulfalene-Pyrimethamineversus Praziquantel in the Treatment of Schistosoma mansoni in Kenyan Children: An Open-Label, Randomized, Exploratory Trial.

Unlike praziquantel, artemisinin derivatives are effective against juvenile schistosome worms. We assessed the efficacy and safety of a single oral dose of artesunate plus sulfalene-pyrimethamine versus praziquantel in the treatment of Schistosoma mansoni. Seventy-three schoolchildren (aged 9-15 years) with confirmed S. mansoni infection in Rarieda, western Kenya, were randomly assigned to receive either a single oral dose of artesunate plus sulfalene-pyrimethamine (n = 39) or a single dose of praziquantel (n = 34). The cure and egg reduction rates at 4 weeks posttreatment were 69.4% (25/36) versus 80.6% (25/31) (P = 0.297) and 99.1% versus 97.5% (P = 0.607) in the artesunate plus sulfalene-pyrimethamine group versus praziquantel group, respectively. Fourteen children developed adverse events, and there were no serious adverse events. A single oral dose of artesunate plus sulfalene-pyrimethamine has efficacy comparable to that of praziquantel in the treatment of S. mansoni, but these results should be confirmed in larger randomized controlled trials.

Adolescents' Perspective Regarding a Community-Wide Mass Drug Administration Program for Soil-Transmitted Helminths in India.

This study was undertaken to understand the perspective of adolescents in endemic communities of India regarding soil-transmitted helminth (STH) infections and community-wide mass drug administration (cMDA). A multicountry community-based cluster-randomized trial, the Deworm3 trial, tested the feasibility of interrupting STH transmission with cMDA, where all individuals aged 1-99 are treated empirically with albendazole. Using a guideline based on the Consolidated Framework for Implementation Research, eight focus group discussions were conducted among 57 adolescents from the trial site in India and analyzed on ATLAS.ti 8.0 software using an a priori thematic codebook. Adolescents believed that adults could be a source of STH infection because they were not routinely dewormed like the children through the national deworming program. Perceived benefits of cMDA for all were better health and increased work efficiency. Perceived barriers to adults' participation in cMDA was their mistrust about the program, fear of side effects, perceived low risk of infection, and absence during drug distribution. To encourage adult participation in cMDAs, adolescents suggested community outreach activities, engaging village influencers and health workers, and tailoring drug distribution to when adults would be available. Adolescents were confident in their ability to be change agents within their households for treatment compliance. Adolescents provided insights into potential barriers and solutions to improve adult participation in cMDA, identified best practices of cMDA delivery, and suggested that they have unique roles as change agents to increase their household participation in cMDA.

Revisiting anthelmintic resistance in sheep flocks from São Paulo State, Brazil.

Haemonchus contortus and Trichostrongylus colubriformis are the most important gastrointestinal nematodes causing serious losses in sheep production of tropical and subtropical regions. Prophylaxis of gastrointestinal nematode infections is based on anthelmintics use, but their frequent administration selects multiple-resistant parasites. To evaluate how the situation has changed over the last decades, the anthelmintic resistance status of gastrointestinal nematodes in sheep flocks was assessed in the current study and compared to previous surveys. In each one of the 15 flocks evaluated, animals (n ≥ 7) were allocated into at least five groups and treated as follows: 1) untreated control; 2) albendazole; 3) levamisole; 4) ivermectin; and 5) monepantel. If more animals were available, two additional groups were included: 6) closantel, and 7) moxidectin. The faecal egg count reduction test (FECRT) was carried out to evaluate the pre- and post-treatment using the SHINY tool. Haemonchus spp. was the most prevalent nematode from faecal cultures. The mean efficacy of albendazole was 40%. Only in two farms, levamisole presented a relatively high percentage of reduction in the FECRT about 90%, while ivermectin and moxidectin presented the worst mean efficacy of 34% and 21% among all farms, respectively. Like other anthelmintics, closantel demonstrated low efficacy (63%) across all farms evaluated. Monepantel presented an overall mean efficacy of 79%, but it was the only anthelmintic that presented efficacy ≥95%, in five farms. The results revealed that gastrointestinal nematodes with multiple anthelmintic resistance were prevalent in all 15 sheep herds. The research suggests that nematodes are becoming more and more resistant to various anthelmintic compounds, which has made the problem worse. This circumstance highlights the necessity to put into practice sustainable and long-lasting methods to prevent gastrointestinal nematode infections in sheep husbandry.

Getting around the roundworms: Identifying knowledge gaps and research priorities for the ascarids.

The ascarids are a large group of parasitic nematodes that infect a wide range of animal species. In humans, they cause neglected diseases of poverty; many animal parasites also cause zoonotic infections in people. Control measures include hygiene and anthelmintic treatments, but they are not always appropriate or effective and this creates a continuing need to search for better ways to reduce the human, welfare and economic costs of these infections. To this end, Le Studium Institute of Advanced Studies organized a two-day conference to identify major gaps in our understanding of ascarid parasites with a view to setting research priorities that would allow for improved control. The participants identified several key areas for future focus, comprising of advances in genomic analysis and the use of model organisms, especially Caenorhabditis elegans, a more thorough appreciation of the complexity of host-parasite (and parasite-parasite) communications, a search for novel anthelmintic drugs and the development of effective vaccines. The participants agreed to try and maintain informal links in the future that could form the basis for collaborative projects, and to co-operate to organize future meetings and workshops to promote ascarid research.

Anthelmintic efficacy of nitazoxanide in dogs naturally infected with Toxocara canis.

Toxocara canis (T. canis) is a gastrointestinal nematode in dogs, and its larvae also infect humans, causing severe larval migratory disease. Anthelmintic drugs have become the primary means to combat T. canis. In this study, the efficacy of nitazoxanide (NTZ) was tested against all the internal stages of T. canis, including L3 larval stage in vitro experiments and gastrointestinal worm in vivo experiments. In the in vitro experiment, after treatment with NTZ at 7.81 and 62.5 µg/mL for 12 h, the larval mortality efficacy reached 90.0 and 100.0%, respectively. In the in vivo experiments, 100 mg/kg NTZ possessed good anthelmintic efficacy against T. canis, with an egg per gram (EPG) reduction of 99.19%, and 90.00% of dogs cleared with residual worms. These results were comparable to those of the positive control drug. The highest anthelmintic efficacy was observed in the group treated with 150 mg/kg NTZ. Based on faecal egg counts, the number of T. canis eggs decreased by 100.00%, and the percentage of dogs cleared with residual worms achieved 90.00% after 7 days of treatment in the 150-mg/kg NTZ treatment group. In general, NTZ showed great potential to be applied as an anthelmintic against T. canis.

Machine learning prediction of multiple anthelmintic resistance and gastrointestinal nematode control in sheep flocks.

The high prevalence of Haemonchus contortus and its anthelmintic resistance have affected sheep production worldwide. Machine learning approaches are able to investigate the complex relationships among the factors involved in resistance. Classification trees were built to predict multidrug resistance from 36 management practices in 27 sheep flocks. Resistance to five anthelmintics was assessed using a fecal egg count reduction test (FECRT), and 20 flocks with FECRT < 80% for four or five anthelmintics were considered resistant. The data were randomly split into training (75%) and test (25%) sets, resampled 1,000 times, and the classification trees were generated for the training data. Of the 1,000 trees, 24 (2.4%) showed 100% accuracy, sensitivity, and specificity in predicting a flock as resistant or susceptible for the test data. Forage species was a split common to all 24 trees, and the most frequent trees (12/24) were split by forage species, grazing pasture area, and fecal examination. The farming system, Suffolk sheep breed, and anthelmintic choice criteria were practices highlighted in the other trees. These management practices can be used to predict the anthelmintic resistance status and guide measures for gastrointestinal nematode control in sheep flocks.

Epidemiology and field efficacy of anthelmintic drugs associated with gastrointestinal nematodes of sheep in Nejo district, Oromia, Ethiopia.

Gastrointestinal nematodes (GINs) are major constraints to health and productivity of small ruminants. Methods of their control relies mainly on anthelmintic drugs; however, the indiscriminate use of these drugs could lead to the development of anthelmintic resistance (AR). This study aimed to investigate the epidemiology of GINs infection, and field evaluation of anthelmintic efficacy in sheep. The epidemiological data were collected using a cross-sectional study design while a farm-based field study design was employed for the evaluation of anthelminthic efficacy. Furthermore, standard parasitological techniques were employed for qualitative and quantitative worm identification. The overall prevalence indicated 50.3%. Six genera of GINs (Haemonchus, Trichostrongylus, Oesophagostomum/Chabertia, Trichuris, Teladosargia/Ostertagia and Nematodirus) were identified. Among the identified genera, Haemonchus (25.4%) and Trichostrongylus (24.8%) were the dominant genera followed by mixed infection (21.8%), Oesophagostomum/Chabertia (10.4%), Trichuris (7.8%), Teladosargia (Ostertagia) (5.7%) and Nematodirus (4.1%). Mixed infections consisted either of double infections with Haemonchus and Trichostrongylus, or triple infections with Haemonchus, Trichostrongylus and Trichuris. The McMaster egg counting results showed that the mean EPG of infected sheep was 845.6. The results also showed 66 (34.2%), 101 (52.3%) and 26 (13.5%) sheep had low, moderate and heavy worm burden, respectively. Albendazole and Ivermectin showed low efficacy (percentage reductions = 90% and 92%; 95% lower confidence limit = 82.1% and 83.6% respectively) whereas Tetramisole was effective (FECR% = 96.8%; 95% LCL = 93.4%). Factors such as age, body condition, management system and past deworming history of sheep were found to have a statistically significant (p < 0.05) influence on the occurrence and burden of the worms. This is further explained as the highest prevalence and worm burden was detected in sheep of young age (p = 0.008; OR = 0.58; 95% CI = 0.39-0.87), poor body condition (p = 0.001; OR = 0.08; 95% CI = 0.04-0.16) and sheep kept under semi-intensive (p = 0.04; OR = 1.53; 95% CI = 1.02-2.29) with no deworming history for the last two months (p = 0.001; OR = 2.97; 95% CI = 1.94-4.56). The study results revealed that nematode infections were among sheep health constraints that could hurt their productivity while low efficacy of Albendazole and Ivermectin were detected. Therefore, the appropriate management techniques of GIN infections should be designed and implemented. Moreover, a further study involving more sensitive techniques (e.g. Mini-FLOTAC, molecular, and serological techniques) should be conducted by considering different host and environmental risk factors such as production level and seasons.