Ovine helminthosis, a major health constraint to productivity of sheep in Ethiopia

Gastrointestinal parasitosis in cattle: Unveiling the landscape across diverse production systems in Bangladesh

BACKGROUND

Factors influencing parasitosis in cattle in Bangladesh remain inadequately explored, necessitating a comprehensive investigation for interventions and sustainable livestock farming.

OBJECTIVES

We conducted this study to estimate the prevalence and distribution of gastrointestinal parasites, exploring their intricate relationship with farm management practices across a spectrum of small-, medium-, and large-scale commercial farms.

METHODS

We conducted this study in the Chattogram district of Bangladesh. We collected a total of 189 freshly voided faecal samples from different farms. We recorded the age, breed, milking status, sex, body condition score, and anthelmintic use history of the sampled animals. We processed the samples using the direct smear method, with the identification of one egg per sample being considered positive.

RESULTS

We estimated the prevalence of gastrointestinal parasite infection in large-scale (52.1%), medium-scale (54.5%), and small-scale farms (70.0%), with statistically significant differences (p ≤ 0.05). Both pregnant and lactating cows, as well as indigenous cattle, were more likely to have gastrointestinal parasites (p ≤ 0.05). The predominant parasites across farms of all sizes were trematodes (Paramphistomum spp. and Schistosomas spp.) and protozoa (Balantidium coli and Coccidia spp.).

CONCLUSION

Poor farm management practices, such as no pasture management and inadequate deworming regimens, may contribute to the elevated prevalence and infection load observed on small-scale farms. The increased parasitosis in previously dewormed animals can be attributed to the development of anthelmintic resistance against gastrointestinal parasites. Implementing proper and effective deworming strategies is crucial to preventing gastrointestinal parasitosis and mitigating the risk of anthelmintic resistance.

Isolation and Molecular Detection of Mannheimia haemolytica and Pasteurella multocida from Clinically Pneumonic Pasteurellosis Cases of Bonga Sheep Breed and Their Antibiotic Susceptibility Tests in Selected Areas of Southwest Ethiopian Peoples Regional State, Ethiopia

Background

Pneumonic pasteurellosis is a respiratory system disease of sheep caused by Mannheimia haemolytica, Pasteurella multocida, and Bibersteinia trehalosi responsible for the low productivity and economic loss resulting from death and treatment costs. This study was conducted to isolate and molecularly detect causative agents and antibiotic susceptibility tests from a nasal swab sample of the Bonga sheep breed that was suspected to have pneumonic pasteurellosis in selected areas of Southwest Ethiopian Peoples Regional State.

Methods

A cross-sectional study design was used along with purposive sampling of nasal swab samples from sheep that were brought to veterinary clinics during the study period. Bacterial isolation and phenotypic characterization were carried out using microbiological and biochemical tests that followed standard microbiological techniques. To molecularly confirm the isolates, PHSSA and KMT1, species-specific PCR primer genes were used. Using the disc diffusion method, molecularly confirmed isolates were subjected to an in vitro antibiotic susceptibility test.

Results

The 85 samples that were scrutinized had an overall isolation rate of 31.76%, whereas the isolates of Pasteurella multocida and Mannheimia haemolytica had species compositions of 40.7% and 59.25%, respectively. Overall, 12.5% of the Mannheimia haemolytica and 18.18% of the Pasteurella multocida species were verified from phenotypical isolates using the species-specific PCR primer genes PHSSA and KMT1, respectively. An in vitro antibiotic susceptibility test was carried out on all four PCR-confirmed isolates for seven commonly used antibiotics used to treat ovine pasteurellosis in the study area. It was found that both bacterial species were resistant to chloramphenicol and penicillin G.

Conclusion

Using phenotypic and molecular diagnostic techniques, the results of our current inquiry revealed that Pasteurella multocida and Mannheimia haemolytica are the causative agents of ovine pneumonic pasteurellosis in the study area.

Assessment of the Epidemiology of the Gastrointestinal Tract Nematode Parasites in Sheep in Toke Kutaye, West Shoa Zone, Ethiopia

Introduction

Gastrointestinal tract nematodes are considered to be the most significant and underestimated problems that hinder sheep productivity.

Objective

This study aimed to evaluate the epidemiology of gastrointestinal tract nematode infestation of sheep in the Toke Kutaye District of West Shoa Zone, Ethiopia.

Methods

A cross-sectional study was conducted to determine the prevalence and risk factors associated with gastrointestinal tract nematode parasite infestation in sheep. Faecal samples were collected from 384 sheep and subjected to coprological examination, including direct smear, flotation techniques, and Baermann techniques for screening and identifying gastrointestinal nematodes.

Results

The overall prevalence of gastrointestinal tract nematode parasite infestation in sheep in the study area was 284 (73.96%). From the total positive cases, males and females were 97 (82.91%) and 187 (70.04%), respectively. The predominantly detected gastrointestinal tract nematodes of sheep in the study area were Trichostrongylus 111 (28.91%), Oestartagia 55 (14.32%), Haemonchus 42 (10.94%), Oesophagostomum 48 (12.50%), and Trichuris 23 (5.99%). Mixed nematode eggs were noticed in some of the sheep beside the single type of nematode eggs, with a prevalence of 85 (22.14%). The relationship in the occurrence of parasites between sex, age groups, body conditions, and seasons was statistically significant (P = 0.008, P = 0.014, P = 0.001 and P = 0.003), respectively.

Conclusion

The present study is of great importance to add to the existing knowledge of the epidemiology of gastrointestinal tract nematodes of sheep, and the findings are very important to apply the proper control and prevention strategies for gastrointestinal tract nematodes of sheep in the area.

Distribution and prevalence of gastrointestinal tract nematodes of sheep at highland and midland areas, Ethiopia

Gastrointestinal nematodes infections are the most important causes of wastage and decreased productivity. This study was conducted with the objectives of estimating the prevalence of gastrointestinal nematodes infection, and the associated risk factors. The overall prevalence of gastrointestinal nematodes infection was 83% (n = 568). The prevalence of gastrointestinal nematodes infection at Debre-Zeit and Debre-Birhan were 84% and 82.3%, respectively. It was significantly higher in poor body condition and soft faecal consistency (P < 0.05) sheep. The overall mean eggs per gram of faeces was 635.2 (95% CI 590.6-679.9). The mean egg per gram was significantly influenced by site of the study, body condition score and faecal consistency (P < 0.05). The faecal egg count was higher in midland area, and in sheep with poor body condition, and soft faecal consistency and diarrhea. The light and moderate level of infections accounted for 73.8% and 17.3%, respectively. With the coproculture the main genera identified were include: Haemonchus, Trichostrongylus, Teladorsagia/Ostertagia and Trichuris in decreasing order of their abundance. To improve sheep health and productivity their control is crucial. Hence, appropriate animal health extension work and training of sheep farmers how they able to identify anemic and diarrheic sheep are helpful. Moreover, training on how to deworm with correct drug and dose for animal owners is important in the control of these parasites. Further epidemiological studies and survey on the development of anthelmintic resistance in the areas is required.

Anthelmintic activity and non-cytotoxicity of phaeophorbide-a isolated from the leaf of Spondias mombin L

ETHNOPHARMACOLOGICAL RELEVANCE

Helminthosis (worm infection) is a disease of grazing livestock, with significant economic implications. Increasing resistance to existing synthetic anthelmintics used to control helminthosis and the unwanted presence of residues of the anthelmintics reported in meat and dairy products present a serious global health challenge. These challenges have necessitated the development of novel anthelmintics that could combat drug resistance and exhibit better safety profiles. Spondias mombin L. (Anacardiaceae) is a plant that has been used traditionally as a worm expeller.

AIM OF STUDY

The aim of the work reported herein was to isolate and characterise anthelmintic compound(s) from S. mombin leaf, establishing their bioactivity and safety profile.

MATERIALS AND METHODS

Adult Haemonchus placei motility assay was used to assess anthelmintic bioactivity. Bioassay-guided chromatographic fractionation of acetone extract of S. mombin leaf was carried out on a silica gel stationary phase. The structure of the compound was elucidated using spectroscopy (¹H and ¹³C NMR) and Liquid Chromatography-Mass Spectrometry (LC-ESI-MS). Screening to exclude potential cytotoxicity against mammalian cells (H460, Caco-2, MC3T3-E1) was done using alamar blue (AB) and CellTitreGlo (CTG) viability reagents.

RESULTS

The acetone extract yielded an active fraction 8 (Ethyl acetate: methanol 90:10; anthelmintic LC₅₀: 3.97 mg/mL), which yielded an active sub-fraction (Ethyl acetate: Methanol 95:5; anthelmintic LC₅₀: 53.8 μg/mL), from which active compound 1 was isolated and identified as phaeophorbide-a (LC₅₀: 23.0 μg/mL or 38.8 μM). The compound was not toxic below 200 μM but weakly cytotoxic at 200 μM.

CONCLUSIONS

Phaeophorbide-a (1) isolated from S. mombin leaf extract and reported in the plant for the first time in this species demonstrated anthelmintic activity. No significant toxicity to mammalian cells was observed. It therefore represents a novel anthelmintic pharmacophore as a potential lead for the development of novel anthelmintics.

Morphometrical and Molecular Characterization of Oesophagostomum columbianum (Chabertiidae: Oesophagostominae) and Haemonchus contortus (Trichostrongylidae: Haemonchinae) Isolated from Goat (Capra hircus) in Sylhet, Bangladesh

This study was aimed at describing two (2) intestinal nematodes from naturally infected native breed of goats (Capra hircus) in Bangladesh, identified as Oesophagostomum columbianum (Curtice, 1890) Stossich 1899 and Haemonchus contortus (Rudolphi, 1803) Cobb, 1898. The identification was made based on morphometric features and was confirmed by amplifying internal transcribed spacer (ITS) and cytochrome c oxidase (cox1) gene. Well-developed lateral alae, distinct cervical papillae anteriorly to esophageal expansion, and male spicule length (0.73-0.79 mm, n = 2) were characteristically observed in O. columbianum. At the same time, male spicule length (0.40-0.46 mm, n = 2) and position of female vulvar flap (4.30-4.54 mm from posterior end, n = 3) were observed in H. contortus. DNA sequence homology of the ITS and cox1 gene of both specimens revealed the same results, showing similarity to the GenBank sequences of O. columbianum (GenBank No. KC715827; JX188470) and H. contortus (GenBank No. KJ724377; HQ389229). Phylogenetic analysis computed by maximum livelihood (ML) from the ITS nucleotide sequences revealed that the O. columbianum and H. contortus isolates identified in this study were clustered in the same clade with isolates from China and Iran, respectively. This study, for the first time, illustrates the characteristics of O. columbianum and H. contortus in Bangladesh, combining both morphological and molecular data. The universal primer-based polymerase chain reaction (PCR) protocol could be an economical and efficient option for researchers from poor resource settings for precise identification of nematodes. The information generated in this study may contribute to formulating effective control strategies against these nematodes.

Gastro-intestinal nematodes in goats in Bangladesh: A large-scale epidemiological study on the prevalence and risk factors

Goats greatly influence the economic sustainability of rural communities. However, parasitic diseases, especially gastrointestinal nematodes (GINs) are a major constraint on profitable small ruminants' production worldwide. During July- 2015 to June- 2016, we conducted a cross sectional study within seven topographic zones of Bangladesh to explore the level of infection and associated risk factors of GINs infections of goats. The study followed standard flotation and modified McMaster techniques. Among 1998 samples from goats; 1241 (62.1%) were found to be infected with one or more species of GINs by fecal examination for nematode eggs. The identified nematodes were strongyles (51.9%), Strongyloides sp. (19.0%) and Trichuris spp. (2.9%). By coproculture, we identified Haemonchus spp., Oesophagostomum spp., Trichostrongylus spp. and Bunostomum spp. in the different topographic zones. According to univariate analysis; young age, other breed than Black Bengal, animals in poor condition, backyard rearing system, muddy housing, illiterate farmers and rainy season were found significantly associated with GINs infections. Besides, other breed than Black Bengal, animals in poor condition, backyard rearing system, muddy housing and illiterate farmers were identified as the risk factors of GINs infections in goats. This is the first detailed epidemiological investigation of GINs of goats in Bangladesh. The epidemiological findings are expected to help formulate effective control strategies against GINs infections in goats by improving health status of animals, management system and education level of the farmers.

In Vitro Anthelmintic Activity of Crude Extracts of Artemisia herba-alba and Punica granatum against Haemonchus contortus

Gastrointestinal nematodes (GINs) are the major limiting factor for the successfulness of livestock production throughout the world. Emergence of resistance strains as well as scarcity and high cost of the currently available drugs has led to the evaluation of other alternative helminth control options, mainly from plants. The current study is aimed at investigating the in vitro anthelmintic efficacy of crude methanolic extracts of two traditionally important medicinal plants, Artemisia herba-alba and Punica granatum, against Haemonchus contortus using adult motility assay (AMA) and egg hatch inhibition assay (EHIA). Four graded concentrations of the extracts were tested for both the AMA (10, 5, 2.5, and 1.25 mg/mg) and EHIA (0.1, 0.25, 0.5, and 1 mg/mL) in replicates. Albendazole and phosphate-buffered saline (AMA) or distilled water (EHIA) were used as the positive and negative controls, respectively. The crude extracts of A. herba-alba and P. granatum exhibited a potential anthelmintic activity at all dose levels in a concentration- and time-dependent fashion. The highest concentration (10 mg/mL) of all the extracts caused a significantly (p < 0.05) superior nematocidal activity compared to the negative control. Moreover, significant and concentration-dependent egg hatching inhibition effect was observed from both plant extracts. Maximal (98.67%) egg hatching inhibition effect was exhibited by the flower extract of A. herba-alba at 1 mg/mL concentration. The relative egg hatch inhibition efficacy indicated that both plants caused a significantly (p < 0.05) greater egg hatch inhibition within 48 hr of exposure. The current study validated the traditional use of both plants as a natural anthelmintic against H. contortus justifying a need to undertake detail pharmacological and toxicological investigation on both plants.

Epidemiology of strongyle nematode infections and first report of benzimidazole resistance in Haemonchus contortus in goats in South Darfur State, Sudan

BACKGROUND

Since pastoralists in South Darfur, Sudan, had complained about lack of albendazole (ABZ) efficacy to control nematodes in goats, the frequency of infection with gastrointestinal helminths was studied before in vivo faecal egg count reduction tests (FECRT) were conducted using ABZ orally either at the dose recommended for sheep, 5 mg/kg body weight (bw) or at 10 mg/kg bw. Experiments included goats naturally infected with gastrointestinal nematodes or experimentally infected with local Haemonchus contortus isolates. Three study areas (Nyala, Beleil and Kass) were visited in autumn or winter.

RESULTS

Out of 478 screened goats, 82.4% were infected with gastrointestinal helminths and 82% were shedding eggs of strongyle nematodes with 90% of the strongyle larvae representing Haemonchus spp. A FECRT using naturally infected goats (n = 225: 71 untreated, 104 and 50 treated with 5 and 10 mg ABZ/kg bw, respectively) detected reduced ABZ efficacy in Nyala and Kass. Paired and unpaired FECRT calculations detected reductions of 72-92% with samples taken at 8 days post treatment with 5 mg ABZ/kg bw and of 85-94% with 10 mg ABZ/kg bw. The FECRT based on day 14 post treatment samples showed reductions of 69-77% with 5 mg/kg and of 75-87% with 10 mg ABZ/kg bw. In Beleil, ABZ efficacy was 95%. In the egg hatch test EC₅₀ values for Nyala and Kass ranged from 0.12-0.24 μg thiabendazole/ml, corresponding to benzimidazole resistant phenotypes. Only Haemonchus spp. larvae were present after treatments in coprocultures. When the efficacy was evaluated experimentally using isolates of H. contortus from Nyala and Kass, the 5 mg ABZ/kg dose revealed reductions of 76-78% on day 8 and of 62-70% on day 14 with the unpaired method. Using 10 mg ABZ/kg, the FECR was still only 77-82%.

CONCLUSIONS

Both, in vivo and in vitro methods detected resistant H. contortus populations in goats from South Darfur State. The time point 14 days post treatment was more sensitive for detection of ABZ resistance than 8 days post treatment. This is the first report on the occurrence of anthelmintic resistance in Sudan confirming that anthelmintic resistance selection is occurring in African subsistence farming systems.

Parasitic infections as major cause of abattoir condemnations in cattle slaughtered at an Ethiopian abattoir: 10-year retrospective study

Abattoirs are vital for gathering information on animal diseases and protecting the public from consuming infected or unhygienic meat. To assess the major reasons for organ and carcass condemnations and their financial implications, we reviewed 10-year abattoir records of slaughtered bovines between January 2005 and December 2014 at Kombolcha ELFORA abattoir, north-east Ethiopia. Of the 46,913 cattle slaughtered during that period, 17,963 (38.3%) had at least one disease condition. Lungs (10.67%) and liver (25%) were the most affected and condemned organs, followed by heart (1.53%), head (0.56%), tongue (0.17%) and kidney (0.32%). The major conditions responsible for condemnation were fasciolosis (49.89%), hydatid cyst (55.55%), pericarditis (78.2%), hydronephrosis (35.8%), abscess (71.7%) and abscess (43.9%), in liver, lung, heart, kidneys, head and tongue, respectively. The direct financial losses incurred from organ and carcass condemnation over the 10-year period amounted to ETB 1,219,399 (USD 61,946.9), with parasitic diseases such as fascioliasis and hydatidosis accounting for ETB 256,837.5 (USD 13,047.64) and ETB 170,827.5 (USD 8678.23) in losses, respectively. This study describes a significant loss of cheap and reliable sources of protein due to non-utilization of infected organs or carcasses, emphasizing the need to implement integrated approaches in disease surveillance and control programmes.

Performance of Arsi-Bale sheep fed urea treated maize cob as basal diet and supplemented with graded levels of concentrate mixture

The experiment was conducted using 20 yearling intact male Arsi-Bale sheep with a mean body weight of 20.56 ± 0.45 (mean ± SD) to investigate the performance and economic benefit of graded levels of concentrate supplementation to urea-treated maize cob (UTMC)-based diet. The experiment consisted of 7 days of digestibility trial and subsequent 90 days of feeding trial. Before the commencement of the experiment, sheep were vaccinated against common infectious diseases, dewormed, and disinfected against internal and external parasites, respectively. The experimental design was randomized complete block design. The sheep were grouped into five blocks of four animals based on their initial body weight, and one animal from each block was randomly assigned to one of the four treatments. The treatments included ad libitum feeding of UTMC (T1) and supplementation with a concentrate mixture composed of wheat bran (WB) and noug seed cake (NSC) in 2:1 ratio, which were offered at 150 g (T2), 250 g (T3), and 350 g (T4) DM/head/day. The CP content of the UTMC was 9.3% on DM basis. The daily DM intake of UTMC was higher (P < 0.001) for T4 (614.6 g) compared to T1 (505.1 g), T2 (538.9 g), and T3 (590.3 g). Total DM intake was higher (P < 0.001) for supplemented treatments T2 (688.4 g), T3 (844.1 g), and T4 (966.9 g). Supplementation did not improve (P > 0.05) digestibility of DM, OM, NDF, and ADF, except CP digestibility which was significant (P < 0.001) across treatments. Supplementation increased (P < 0.001) final body weight (FBWT), feed conversion efficiency (FCE), and average daily weight gain (ADG). The average daily gain (ADG) was highest (P < 0.001) in T4 (80.8 ± 7.74 g/day) followed by T3 (33.3 ± 7.74 g/day) and T2 (23.1 ± 0.95 kg) whereas the un-supplemented animals lost about 9.2 g/day. The highest total return, net income, and marginal rate of return were observed in higher level supplemented sheep than the control. Therefore, T4 improved biological performance and marginal rate of return than the other treatments and can be considered as better alternative feed supplement in UTMC-based feeding of Arsi-Bale sheep in Ethiopia.

Investigations into nematode parasites of goats in pastoral and crop livestock systems of Ethiopia

We generated epidemiological information on the prevalence of nematode parasites and possible resistance/resilience of goats in three areas, Bati, Shinille, and Borana, of Ethiopia. A total of 350 breeding does were randomly selected and monitored for one year. Fecal egg counts (FEC), packed cell volume (PCV), body weight (BW), body condition score (BC), and fecal larvae identification were done. In Borana, the long rainy season had higher FEC, lower PCV, lower BC, and smaller BW compared to dry and short rainy seasons (p < 0.01). For Bati and Shinille, the differences between the seasons were significant (p < 0.01) but not clear-cut. Breed differences were also evident (p < 0.01) on FEC, PCV, and BW. The mean FEC for Borana goat was 158.5 ± 1.12, whereas for Bati it was 38.9 ± 1.12. Age differences did not have effect on FECs, PCV, and BC. No differences in parasite load, as reflected by FEC, was verified between male and female goats. In the wet season, large numbers of larvae were recovered from the study sites except for Bati. In the three sites, Haemonchus contortus followed by Trichostrongylus colubriformis were the dominant species. In the dry season, however, very little number of larvae was recovered, only of H. contortus in Bati and of H. contortus and T. colubriformis in Borana. Generally, the level of nematode infection was low. Therefore, nematode parasites are not a major problem and strategic control program using broad spectrum anthelmintic is not advisable. Rather, monitoring parasite load and selective de-worming should be sufficient to reduce productivity loses and pasture contamination.

Anthelmintic administration to small ruminants in emergency drought responses: assessing the impact in two locations of northern Kenya

Internal parasites are a significant determinant of the productivity of ruminant species in the tropics. Provision of anthelmintics has become a predominant part of animal health interventions in emergency drought responses, aiming to maintain the food conversion efficiency of livestock when pasture is scarce. This study aimed to assess the owner-perceived impact of anthelmintic provision on the health and productivity of small ruminants in the drought-prone counties of Isiolo and Marsabit, northern Kenya. Participatory approaches were used to retrospectively measure differences in key indicators of livestock output before and after anthelmintic administration. Results showed that there was no perceived impact of anthelmintic administration during droughts on small ruminant health and productivity, but some benefit of anthelmintic administration during rainy season was perceived. The study also provided some evidence of potential differences in the epidemiology of internal parasites between the counties. These findings may be utilised to inform future livestock intervention programmes in drought-prone areas.

Identification of novel loci associated with gastrointestinal parasite resistance in a Red Maasai x Dorper backcross population

Gastrointestinal (GI) parasitic infection is the main health constraint for small ruminant production, causing loss of weight and/or death. Red Maasai sheep have adapted to a tropical environment where extreme parasite exposure is a constant, especially with highly pathogenic Haemonchus contortus. This breed has been reported to be resistant to gastrointestinal parasite infection, hence it is considered an invaluable resource to study associations between host genetics and resistance. The aim of this study was to identify polymorphisms strongly associated with host resistance in a double backcross population derived from Red Maasai and Dorper sheep using a SNP-based GWAS analysis. The animals that were genotyped represented the most resistant and susceptible individuals based on the tails of phenotypic distribution (10% each) for average faecal egg counts (AVFEC). AVFEC, packed cell volume (AVPCV), and live weight (AVLWT) were adjusted for fixed effects and co-variables, and an association analysis was run using EMMAX. Revised significance levels were calculated using 100,000 permutation tests. The top five significant SNP markers with - log10 p-values >3.794 were observed on five different chromosomes for AVFEC, and BLUPPf90/PostGSf90 results confirmed EMMAX significant regions for this trait. One of these regions included a cluster of significant SNP on chromosome (Chr) 6 not in linkage disequilibrium to each other. This genomic location contains annotated genes involved in cytokine signalling, haemostasis and mucus biosynthesis. Only one association detected on Chr 7 was significant for both AVPCV and AVLWT. The results generated here reveal candidate immune variants for genes involved in differential response to infection and provide additional SNP marker information that has potential to aid selection of resistance to gastrointestinal parasites in sheep of a similar genetic background to the double backcross population.

Characterization of Oesophagostomum asperum and O. columbianum by internal transcribed spacers of nuclear ribosomal DNA

In the present study, the internal transcribed spacers (ITS) of ribosomal DNA (rDNA) of Oesophagostomum asperum and O. columbianum were amplified and sequenced. The ITS-1, 5.8S and ITS-2 rDNA sequences of O. asperum were 374 bp, 153 bp and 259 bp in length, respectively, and the corresponding sequences of O. columbianum were 259, 153 and 218 bp in length, respectively. Sequence differences in the ITS-1 and ITS-2 rDNA between the two Oesophagostomum species were 9.5–10.2% and 12.7–13.9%, respectively. Sequence differences in the ITS-1 and ITS-2 rDNA among members of the genus Oesophagostomum were 2.5–11.6% and 6.8–22.3%, respectively. Based on genetic markers in the ITS rDNA, an effective polymerase chain reaction (PCR) approach was developed to differentiate O. columbianum from O. asperum with a sensitivity of 0.2 ng/μl DNA. Since accurate characterization of parasites at different taxonomic levels is essential for population genetic studies and control of parasitosis, the present findings have important implications for studying epidemiology, taxonomy and population biology, as well as for the control of oesophagostomiasis.

Susceptibility assay of Haemonchus contortus to commonly used anthelmintics in Jimma, southwest Ethiopia

An experimental study to investigate the susceptibility pattern of Haemonchus contortus to commonly used anthelmintics (albendazole, tetramisole, ivermectin, and triclobendazole) was conducted between June and September 2009. Adult H. contortus parasites were collected from a total of 30 sheep slaughtered at Jimma municipal abattoir. The anthelmintics were assessed for egg hatch inhibition ability against H. contortus eggs. The eggs (500 eggs/ml) were incubated with different concentrations (0.25, 0.125, 0.0625, 0.03125, and 0.015625 μg/ml) at 26°C for 48 h. Egg hatching inhibition of different anthelmintics at different concentrations was recorded. The overall mean percent inhibition showed that there was a significant difference (p < 0.05) among the different concentrations. Mean egg hatch inhibition of ivermectin showed the highest result (84.90 %) at 0.25 μg/ml, followed by albendazole (78.77 %), triclobendazole (76.66 %), and tetramisole (78.98 %), respectively. The overall mean percent inhibition showed a significant difference (p < 0.05) among the different anthelmintics. Further evaluation of these anthelmintics was recommended.

Gastrointestinal nematode infections in small ruminants under the traditional husbandry system during the dry season in southern Ethiopia

A cross-sectional study was conducted from November 2008 to February 2009 to investigate the prevalence and intensity of infection and risk factors of gastrointestinal (GI) nematodes in small ruminants kept under the traditional husbandry system in two districts in southern Ethiopia. Faecal samples collected from a total of 510 small ruminants (284 sheep and 226 goats) and analysed by a modified McMaster technique revealed that 222 animals (43.5%) were found to be infected with one or more GI nematodes. Five identical genera of nematodes were found in both sheep and goats, which in order of predominance were Haemonchus (56.3%), Trichostrongylus (39.6%), Oesophagostomum (22.9%), Trichuris (21.6%) and Bunostomum (10.4%). No significant (p > 0.05) differences were observed between sheep and goats proportions except for Trichuris (p < 0.05). In both sheep and goats, most of the animals were heavily infected showing faecal egg counts (FECs) above 1,200 epg. Sheep had a significantly (p < 0.05) higher mean FEC than goats. In sheep and goats, both the prevalence of GI nematodes and mean FEC were significantly (p < 0.001) associated with body condition score and faecal consistency but not with district, sex and age (p > 0.05 for each factor). In conclusion, the observation of a strong association of GI nematodes with poor body condition coupled with heavy intensity of infection in the majority of infected animals and an abundance of nematode genera of widespread economic and pathological significance warrants the institution of appropriate control measures that should necessarily include improvement of the nutritional status of the animals.

Epidemiology of nematode parasites of sheep around Jimma, southwestern Ethiopia

An investigation was made into the epidemiology of nematode infections of sheep in two districts of Jimma zone, southwestern Ethiopia. We used two approaches--long-term monitoring of identified sheep for nematode infection and abattoir or market survey for analysis. In the first monitoring regime, we used 80 lambs [40 sheep (20 per sex) from each district (Dedo and Yebu)] averaging 4-5 months of age. Faecal egg counts (FEC), packed cell volume (PCV) and body weight changes were monitored over a period of 1 year. Additionally, faecal samples were collected (on a weekly basis) from sheep brought to abattoir/market for 1 year to monitor faecal egg counts. The nematode parasite burden, as judged by FEC and PCV, was generally low indicating that the climatic conditions are not conducive to the development and survival of nematode eggs and the free-living stages; hence, little transmission occurred. In the experimental flocks, the highest FEC and lower PCV were recorded during the long rainy season (June to September) with peak in August and September. Faecal samples collected from abattoir/market also followed the same trend. Results from experimental sheep indicated that location had a significant (P < 0.01) effect on FEC, PCV and average daily body weight gain. The FEC and PCV for sheep in Yebu (mid-altitude) district were 126 +/- 3.33 and 30.6 +/- 0.26, whereas the values for Dedo (highland) were 93 +/- 4.35 and 32.0 +/- 0.21, respectively. The results indicate that the highland areas are comparatively less favourable to the survival and development of nematodes. Female lambs had lower FEC and higher PCV compared to male lambs (P < 0.05). The overall nematode parasite challenge in the area, however, is low. We, therefore, recommend rotational grazing management combined with monitoring parasite load and selective treatment to reduce productivity loses and pasture contamination.

Efficacy of albendazole against nematode parasites isolated from a goat farm in Ethiopia: relationship between dose and efficacy in goats

A suspected case of albendazole resistance in a goat farm of Hawassa University was examined using faecal egg count reduction test (FECRT), controlled anthelmintic efficacy test and egg hatch assay (EHA) to verify the development of resistance and/or the need for higher doses of the drug in goats than in sheep. The experiment was conducted in 12 sheep (2 groups: treatment versus control) and 24 goats (4 groups: 3 treatments versus control, n = 6; per group) following artificial infection with infective larvae of Haemonchus contortus and Oesophagostomum columbianum. The first group of sheep and goats were treated orally with albendazole at the dose rate of 3.8 mg/kg body weight (i.e. manufacturer's recommended dose for sheep) while the second group of sheep and the fourth group of goats were left untreated. The second and the third group of goats were treated with albendazole at 5.7 and 7.6 mg/kg respectively. The FECRT showed an efficacy of albendazole in goats to be 65.5, 81.4 and 84.1% at the dose rate of 3.8, 5.7 and 7.6 mg/kg body weight respectively while in sheep it was 62% at the dose rate of 3.8 mg/kg. Increasing the dose to 1.5 the sheep recommended dose induced minor improvement of efficacy in goats; however the efficacy was almost the same at 1.5 and twice the dose recommended for sheep. Worm counts at day 15 post-treatment revealed that H. contortus has developed resistance to albendazole. EHA results also supported these findings. On the other hand, O. columbianum was 100% susceptible at all dose levels tested.