Gastrointestinal nematodes in indigenous Zebu cattle under pastoral and nomadic management systems in the lower plain of the southern highlands of Tanzania

Camel gastrointestinal helminths in selected districts of Fafan zone, eastern Ethiopia

A cross-sectional study was conducted to estimate the incidence and prevalence of helminths in camels in the Jigjiga and Gursum districts of Fafan zone, Somali regional state of Ethiopia. Fecal samples were collected from individual animals and analyzed using a McMaster fecal flotation method. Fecal samples were mixed with water and centrifuged to remove excess debris prior to mixing with flotation solution and performing the McMaster. For each sample, the number and types of parasite eggs present were recorded. 77.3% of examined camels were found harboring gastrointestinal parasites. Trichostrongylid spp. (68.06%) were the predominant parasite followed by Strongyloides spp. (25.6%), Trichuris spp. (15.5%) and Monezia spp. (8.4%). Risk factors for gastrointestinal parasite prevalence included age, body condition score and fecal quality (P < 0.05). Camels from the Gursum district had a significantly higher mean egg count than camels from the Jigjiga district (868.9 ± 1064.2 vs 351 ± 422.4; F = 20.8, P < 0.001). Moreover, there was a statistically significant difference in mean egg count between the sexes (F = 5.9, P = 0.02), with females (724.6 ± 960.6) having higher egg counts than males (373.4 ± 470.6). This study indicates that gastrointestinal helminths are highly prevalent and may affect the health and productivity of the camels in pastoral areas of Fafan zone.

Molecular identification of different Trichostrongylus species infecting sheep and goats from Dakahlia governorate, Egypt

Nematodes of genus Trichostrongylus can cause remarkable economic losses in the small ruminant`s industry and some species have a zoonotic potential. Since the most common source for human infection is the infected animals, accurate identification of different Trichostrongylus species in animals would reflect the species that can infect humans from the same area. The objective of the present study is to identify common Trichostrongylus species infecting small ruminants in Dakahlia governorate, Egypt using molecular-based techniques. Fecal samples from 340 sheep and 115 goats from rural areas in 3 cities of Dakahlia governorate and 2 cities at its borders were collected, and the strongyle-type eggs were detected in 33.2% and 14.7% of sheep and goats, respectively. PCR amplification of the internal transcribed spacer of the ribosomal DNA (ITS2 rDNA) for 3 Trichostrongylus spp.; T. axei, T. colubriformis and T. vitrinus was conducted for eggs harvested from 25 sheep and 16 goat samples. Two species were detected; T. axei (in 16 sheep and 14 goats) and T. colubriformis (in 2 sheep but no goats). This is the first report of T. colubriformis in sheep from Dakahlia governorate, where this species was reported earlier from humans. No T. vitrinus was detected in any tested sample of sheep or goats. Purified PCR products of T. axei isolates were successfully sequenced and revealed 3 haplotypes; 2 from sheep and 1 from goats, and the isolates are related genetically to T. axei isolates from camels in Egypt. Phylogenetic analysis of the Genbank-retrieved ITS2-amplified T. axei isolates worldwide suggested the existence of genetic variants. Earlier reports on the identified Trichostrongylus spp. in different animals from Egypt as well as African and Arabian countries are tabulated.

A systematic review and meta-analysis on the prevalence, distribution and nematode species diversity in small ruminants: a Nigerian perspective

Despite the global projections that agriculture will have to feed an additional 3 billion of the world's population in the nearest future, the global trends and negative impacts of nematodes on livestock productivity are still on the increase. Here, we reported the burden of gastrointestinal nematodes in small ruminants in Nigeria. Six thousand, five hundred and eighty one of the 13,259 small ruminants reported in 40 eligible studies across 18 Nigerian States were infected with at least one nematode species, yielding an overall pooled prevalence (PP) of 58.3% (95% CI 48.8, 67.2). Regional PP varied significantly (P < 0.001) and ranged between 19.5 (95% CI 5.8, 48.7) and 83.7% (95% CI 68.5, 92.3). Seasonal PP was higher in the dry (Prev: 56.5%, 95% CI 34.2, 76.4) than the rainy (Prev: 43.2%, 95% CI 26.7, 61.3) season. Haemonchus species were the most prevalent 21.3% while, Trichuris ovis and Strongyloides species had the widest geographic distribution. Several species of nematodes of small ruminants are highly prevalent in Nigeria. An all-inclusive approach involving public education and standardised management practices that involve adequate hygiene and sanitation, strategic and prophylactic use of anthelmintics, rotational grazing and the control of arthropod intermediate hosts will reduce the economic losses due to these parasites and curtail possible transmission to humans.

Management factors associated with time-to-onset and fecal egg/oocyst counts of gastrointestinal parasites in heifer calves on Kenyan smallholder farms

A prospective cohort study on zero-grazed smallholder dairy farms was conducted to determine factors associated with onset and counts of gastrointestinal parasitism in heifer calves. The researchers recruited 187 newborn heifer calves from 150 farms in Kenya. Over 16 months, farm visits every two months were used to collect rectal fecal samples and animal- and farm-level measures. Fecal samples underwent centrifugal fecal flotation with Sheather's sugar to determine counts of strongyle-type eggs and coccidia oocysts. Cox proportional hazard (Cox PH) analysis and mixed-effects negative binomial (MeNB) regression determined factors associated with time-to-onset and counts of strongyle-type eggs and coccidia oocysts, respectively (P < 0.05). The incidence rate of strongyles was 0.0011 cases/animal-day while coccidia was 0.0073 cases /animal-day. Incidence risks of strongyles and coccidia over the study period were 28.3 % (53/187) and 87.7 % (164/187), respectively. For infected calves, median time-to-onset for strongyles and coccidia was 78 (interquartile-range: IQR 38-117) and 43 (IQR 29-92) days, respectively. In the final Cox PH model for strongyles, breed (Ayrshires and Jerseys) and weaned calves had a greater hazard of infection than Friesians and preweaned calves, respectively. Calf tethering outside the pen was associated with a higher hazard of strongyle infection. In the final Cox PH model for coccidia, calves with watery and/or hemorrhagic diarrhea had a higher hazard compared with those with hard or soft feces. Weaning status and birth weight (kg) were time-varying covariates, leading to increased hazard over time. In the final MeNB model for strongyles, weaned animals had higher counts than those still on milk. In an interaction variable, the predicted strongyle-type egg counts increased with longer duration of farm operation when herd size was less than five cattle, but decreased when herd size was more than five. In the final MeNB model for coccidia, calves sometimes tethered outside their pens had higher counts than those continuously enclosed in the pen. Calf pen floors with either scant manure or moderate slurry had higher predicted counts than those on a clean pen floor. Calves with watery or hemorrhagic diarrhea and fed fresh Napier grass (Pennisetum purpureum) had higher counts compared with soft or hard feces and those not given fresh Napier, respectively. In an interaction variable, calves experiencing diarrhea and raised on elevated slatted floors had lower oocyst counts compared with those having diarrhea but not on elevated floors. The identified management practices associated with onset and counts of gastrointestinal parasitism should be considered in control efforts.

Protozoan and helminthes parasites endorsed by imported camels (Camel dromedaries) to Egypt

The prevalence and species spectrum of some blood and intestinal parasites affecting imported camels was studied on a total of 120 clinically suspected camels (males) imported to Egypt from Sudan during the period from January till July 2016 in Abu-Simbel quarantine station, Aswan governorate. Blood and fecal samples were collected from all camels under the study. The fecal samples were collected and examined by sedimentation-floatation techniques for detection of parasitic eggs/oocysts. Coprological examination revealed that the prevalence rate of the parasitic infection was 60% (72 out of 120). Eighteen species of helminthes/protozoan parasites eggs/oocysts were encountered stongyles species were the hightest prevalent of nematodes 12.5%. Four genera of flat worms were identified in the present study including Paramphistomum sp. 0.8%, Fasciola sp. 3.3%, Moniezia sp. 7.5% and Dicrocoelim sp. 0.8%. Four species of Eimeria were identified (E. cameli, E. dromedarii, E. rajasthaniand E. pellerdyi) in infected camels the commenst one is E. cameli 15.8%, Cryptospridium sp. and Balatidium coli were recorded with a prevalence rate about 15.8%, 8.3% and 6.7% respectively. Blood smears from jugular vein revealed that 2.5% of camels were infected with Dipetalonema evansi. Wide spectrum and high prevalence of internal parasites were observed in the present study which may be lead to severe economic losses, so the application of control measures and treatment of infected camels with specific and effective drugs during the quarantine period are most important to prevent spreading of parasitic infestation and/or introduction of parasites previously not exist in our country.

Pathological findings of condemned bovine liver specimens and associated economic loss at Nyabugogo abattoir, Kigali, Rwanda

There are no published abattoir bovine hepatic lesion prevalence studies in cattle in Rwanda. This study estimated that 12.3% of the livers (n=4751) examined at Nyabugogo slaughterhouse in Kigali were condemned. Condemnation prejudiced the nation of 3492.00kg of meat with attendant economic losses of US$8932.40 during the study period. Risk factors for these lesions were also assessed. Male and female animals from 11 districts were used in this study. Hepatic lesions were higher in females (14.6%; n=1494) than in males (11.1%; n=3257). About 78.7% of the condemnations were due to fascioliasis, followed by abscesses (5.7%), hepatitis (5.3%), cirrhosis (4%) and other lesions (6.3%). Female animal livers showed more fascioliasis and abscesses (82.2% and 9.5%) than male animal livers (73.3% and 3.3%). The highest rate of condemnation was observed from Kayonza (40.2%; n=413) and the least was from Gakenke district (0.9%; n=1031). Cattle from the Eastern Province showed significantly (P<0.05) higher prevalence of condemnations (26.8%) than the rest of the provinces. Liver specimens of animals below 3 years and above 6 years of age had a significantly higher (P<0.05) condemnation rate (14.4%) (n=3000 and n=769) than the 3-6year age-group at 4.1% (n=982). We conclude that fascioliasis was responsible for a significant proportion of the liver condemnations at Nyabugogo slaughterhouse. Being a zoonosis, we recommend an epidemio-surveillance, implementation of control measures and anthelmintic resistance investigation for fascioliasis in Rwanda.

Vaccination of sheep and cattle against haemonchosis

Vaccines against gastrointestinal nematodes are one potential option for the control of parasitic gastroenteritis in ruminants. Excretory/secretory (E/S) and hidden antigens are being studied as candidates for vaccines against Haemonchus spp., which is a major parasite in cattle and small ruminants that are raised in warm climates. Protection has been observed after vaccination with some E/S proteases, particularly cysteine proteases and with some glycans that are abundant on the surfaces and in the secretory products of helminths. However, the most promising results are being obtained with glycoprotein antigens extracted from the microvillar surfaces of the Haemonchus contortus intestinal cells. These antigens are called 'hidden' because they are not exposed to the host's immune system during infection. Thus far, recombinant forms of these antigens have not been usefully protective. However, because only 5 μg of antigen is required per dose, production of a native antigen vaccine from adult parasites has been found to be practical and commercially viable. Trials indicate that a vaccine made from one particular isolate will cross-protect against geographically distant isolates.

Variation and covariation in strongyle infection in East African shorthorn zebu calves

Parasite burden varies widely between individuals within a population, and can covary with multiple aspects of individual phenotype. Here we investigate the sources of variation in faecal strongyle eggs counts, and its association with body weight and a suite of haematological measures, in a cohort of indigenous zebu calves in Western Kenya, using relatedness matrices reconstructed from single nucleotide polymorphism (SNP) genotypes. Strongyle egg count was heritable (h² = 23·9%, s.e. = 11·8%) and we also found heritability of white blood cell counts (WBC) (h² = 27·6%, s.e. = 10·6%). All the traits investigated showed negative phenotypic covariances with strongyle egg count throughout the first year: high worm counts were associated with low values of WBC, red blood cell count, total serum protein and absolute eosinophil count. Furthermore, calf body weight at 1 week old was a significant predictor of strongyle EPG at 16–51 weeks, with smaller calves having a higher strongyle egg count later in life. Our results indicate a genetic basis to strongyle EPG in this population, and also reveal consistently strong negative associations between strongyle infection and other important aspects of the multivariate phenotype.

Comparative analyses of the complete mitochondrial genomes of the two ruminant hookworms Bunostomum trigonocephalum and Bunostomum phlebotomum

Bunostomum trigonocephalum and Bunostomum phlebotomum are blood-feeding hookworms of sheep and cattle, causing considerable economic losses to the live stock industries. Studying genetic variability within and among hookworm populations is critical to addressing epidemiological and ecological questions. Mitochondrial (mt) DNA is known to provide useful markers for investigations of population genetics of hookworms, but mt genome sequence data are scant. In the present study, the complete mitochondrial DNA (mtDNA) sequences of the sheep and goat hookworm B. trigonocephalum were determined for the first time, and the mt genome of B. phlebotomum from yak in China was also sequenced for comparative analyses of their gene contents and genome organizations. The lengths of mt DNA sequences of B. trigonocephalum sheep isolate, B. trigonocephalum goat isolate and B. phlebotomum China yak isolate were 13,764bp, 13,771bp and 13,803bp in size, respectively. The identity of the mt genomes was 99.7% between B. trigonocephalum sheep isolate and B. trigonocephalum goat isolate. The identity of B. phlebotomum China yak isolate mt genomes was 85.3% with B. trigonocephalum sheep isolate, and 85.2% with B. trigonocephalum goat isolate. All the mt genes of the two hookworms were transcribed in the same direction and gene arrangements were consistent with those of the GA3 type, including 12 protein-coding genes, 2 rRNA genes and 22 tRNA genes, but lacking ATP synthetase subunit 8 gene. The mt genomes of B. trigonocephalum and B. phlebotomum were similar to prefer bases A and T, the contents of A+T are 76.5% (sheep isolate), 76.4% (goat isolate) and 76.9% (China yak isolate), respectively. Phylogenetic relationships reconstructed using concatenated amino acid sequences of 12 protein-coding genes with three methods (maximum likelihood, Bayesian inference and neighbor joining) revealed that the B. trigonocephalum and B. phlebotomum represent distinct but closely-related species. These data provide novel and useful genetic markers for studying the systematics, and population genetics of the two ruminant hookworms.

Supplements containing Acacia karroo foliage reduce nematode burdens in Nguni and crossbred cattle

The objective of this study was to compare nematode worm burdens in Nguni and crossbred cattle supplemented with Acacia karroo leaf meal. Eighteen Nguni (274.4 ± 17.34 kg) and 12 crossbred (230.5 ± 14.62 kg) steers aged 19 months were allocated to three dietary treatments: A. karroo leaf meal, sunflower cake and control with no supplement. Steers in all the treatments grazed on natural pasture whereas those on A. karroo leaf meal and sunflower cake diets were given an additional 1.5 kg and 650 g of feed, respectively, to supply 150 g of protein per day for 60 days. Faecal samples collected from the steers’ recta every fortnight were examined for nematode egg types using the modified McMaster technique. At slaughter, the abomasa and intestines were collected, opened and washed for worm identification. Nguni steers supplemented with the A. karroo leaf meal diet had the lowest mean strongyles egg counts and mean total egg counts (P < 0.05). Steers that received the A. karroo leaf meal and sunflower cake diets had lower Haemonchus contortus and Oesophagostomum colombianum worm burdens than those that received the control diet (P < 0.05). Mean strongyles and Strongyloides egg counts, and H. contortus and Oes. colombianum worm counts were negatively correlated with average daily gain and body condition scores (P < 0.05). Generally, Nguni cattle supplemented with A. karroo leaf meal had the lowest egg loads and worm burdens. It was concluded that supplementing cattle with A. karroo could reduce nematode burdens.

Effectiveness of strategic anthelmintic treatments in the control of gastrointestinal nematodes and Fasciola gigantica in cattle in Iringa region, Tanzania

A longitudinal field trial was conducted to determine the effectiveness of strategic anthelmintic treatments in the control of gastrointestinal (GI) nematodes and Fasciola gigantica in cattle. A total of 167 cattle (6-18 months) from three large-scale dairy farms, four traditional farms and nine small-scale dairy farms were randomly selected. The selected animals on each farm were ear tagged and allocated into three groups based on live weight and treated as follows: Group T4 was treated with albendazole 10% drench at 10 mg/kg four times a year (mid rainy, end of the rain, mid dry and late dry/early rainy season). Group T2 was treated with albendazole 10% drench at 10 mg/kg two times a year (mid rainy and late dry/early rainy season). Group UT remained as untreated control. Faecal, blood and pasture samples were taken every month for 13 months. In addition, individual body weight (BWT) was measured on every sampling date. Results showed that two and four strategic treatments significantly reduced faecal egg counts (FEC) by 49.5% and 62.3% respectively compared to untreated control animals (P < 0.001). Two and four strategic treatments per year significantly reduced the proportion of animals passing Fasciola eggs in faeces by 30.6% and 51.7% (P < 0.001), respectively. Animals treated two and four times a year significantly outgained untreated animals by 14.8 kg and 17.7 kg respectively at the end of the trial (P < 0.05). The management system had a significant effect on packed cell volume and the proportion of animals passing Fasciola eggs in faeces (P < 0.05). The programme of two strategic treatments per year was only effective in controlling GI nematodes. It is concluded that a programme of four strategic treatments per year was effective in controlling GI nematodes and F. gigantica and improved weight gain.

Cross-sectional prevalence of helminth infections in cattle on traditional, small-scale and large-scale dairy farms in Iringa district, Tanzania

A cross-sectional study was carried out to determine the prevalence of gastrointestinal (GI) nematodes and flukes (Fasciola and amphistomes) infection in communally grazed traditional cattle, zero-grazed small-scale dairy cattle and intensively grazed large-scale dairy cattle through examination of helminth eggs in faeces. Results indicated that the type of management, especially the grazing habit, has a significant influence on the prevalence and intensity of GI nematodes and flukes. The prevalence of GI nematodes in traditional, large-scale dairy and small-scale dairy cattle was 67%, 44.4% and 37%, respectively, with the highest faecal egg counts in calves. The overall prevalence of Fasciola gigantica in traditional, large-scale dairy and small-scale dairy cattle was 63.8%, 46.2% and 28.4%, respectively. The prevalence of amphistomes was 81.9%, 55.5% and 41.1% in traditional, large-scale dairy and small-scale dairy cattle, respectively. The high prevalence of flukes in the traditional system was attributed to communal grazing and watering management practices. Stomach flukes recovered in examined cattle at the abattoir were Calicophoron microbothrium and Cotylophoron jacksoni. About 42.1% of infected animals had both Fasciola and amphistomes. The prevalence of both GI nematodes and flukes varied greatly among villages and farms. The prevalence of both Fasciola and amphistomes was higher in adults (58.5%, 75.2%) than in yearlings (36.5%, 51.5%) or calves (24.9%, 47.2%). The variation in the prevalence of both GI nematodes and flukes among management and age groups within systems can be used as an entry point towards rational use of anthelmintics for each management system. More studies on seasonal transmission pattern of all these parasites are required in order to design rational, economic and locally sustainable parasite control programmes.

Epidemiology of gastrointestinal nematodes in cattle on traditional, small-scale dairy and large-scale dairy farms in Iringa district, Tanzania

A longitudinal study was carried out to determine the prevalence, distribution and intensity of gastrointestinal (GI) nematodes in traditional, small-scale dairy and large-scale dairy cattle farms in Iringa district, Southern highlands of Tanzania. Coprological examination of cohorts for GI nematode eggs in faeces, tracer worm counts and pasture larval counts were performed monthly for 1 year. Results indicated that the type of management, especially the grazing habit has a significant influence on the prevalence and intensity of GI nematodes. The predominant nematodes were Cooperia spp. (51.6%), Oesophagostomum radiatum (35.7%) and Haemonchus placei (10.2%). The worm burden in tracers was mainly composed of Cooperia spp. (83%) in large-scale dairy farms, while O. radiatum was dominant (60.8%) in traditional farms. Faecal egg counts (FEC) and tracer worm counts were generally low and FEC peaked only in calves and weaners/yearlings. Adults and all age groups in small-scale dairy farms had very low FEC throughout the year. Pasture larval counts, FEC and tracer worm counts peaked towards the end of the rainy season. Based on conditions of the study area, farmers could save substantial amount of money through strategic treatments as opposed to the previous routine of treating the whole herd at least four times a year. Strategic treatments are recommended in calves and weaners only in traditional and large-scale dairy farms. Strategic treatment of adults and small-scale dairy cattle might be not necessary. Strategic treatments at the end of the rainy/early dry season (May/June) and at the end of the dry/early rainy season (November/December) are recommended in the district. An additional treatment against GI nematodes in calves during the mid rainy season (February/March) might be important.

Worm control practices and anthelmintic usage in traditional and dairy cattle farms in the southern highlands of Tanzania

Worm control practices and anthelmintic usage in 177 cattle farms in Iringa district in the southern highlands of Tanzania was determined through a questionnaire survey. A total of 76 traditional, 92 small-scale dairy and 9 large-scale dairy cattle farms were included in the survey. Results indicated that 87.7% traditional, 97.8% small-scale dairy and 100% large-scale farmers relied solely on the use of anthelmintics, 2.7% traditional farmers used traditional medicines while 9.6% traditional farmers had not any form of worm control practice. Worm infection was ranked the second most important constraint of productivity in cattle in the three production systems. Most farms (57.6% traditional, 35.8% small-scale dairy, 66.7% large-scale dairy) used anthelmintics with a combination of levamisole and oxyclozanide. Benzimidazoles were used only in traditional (25.4%) and small-scale dairy (32.1%) farms while nitroxynil (Trodax) was mostly used in large-scale dairy farms (33.3%). Generally, 40% of farmers treated three or four times a year and the frequency in some farms was surprisingly high for resource poor small-scale farmers. The frequency of anthelmintic treatment was mostly the same regardless of the management system. Treatments in most farms depended on availability of money and drugs and not the epidemiology of parasites. A significant proportion (46.3%, P=0.007) of farmers especially in rural areas failed to follow their pre-planned treatment schedules due to lack of money (86%) and unavailability of drugs (6.6%). Many farmers (58.9%) had used the same type of anthelmintic for four or more consecutive years and 85.3% of them would continue with the same anthelmintic. Farmers in all management systems mostly purchased anthelmintics from private veterinary drug shops and about 43% traditional and 33.3% small-scale dairy farmers mostly in rural areas obtained anthelmintics from village extension officers. Despite the fact that all farmers were aware of worm infection and the associated signs in cattle, 42.5% had poor knowledge on the source of worm infection. Small-scale dairy farmers allowed only a 1-day withdraw period for milk regardless of the type of anthelmintic used and there was no milk and slaughter clearance in traditional farms. It was concluded from this study that worm control in Iringa faces serious constrains and that education of farmers and farm hands is not adequate. Moreover, poor quality control and high price of potent anthelmintics, few extension workers, low income and low education among farmers contributed significantly to erratic worm control practices and anthelmintic usage in peri-urban and rural areas.