Efficacy of VERYL® in the treatment of cattle naturally infected with gastro-intestinal nematodes in Kenya.

Co-infections caused by trypanosomes and gastro-intestinal nematodes (GINs) compromise cattle productivity and their control requires a holistic approach. The effectiveness of trypanocides and anthelmintics is compromised by increasing resistance. Use of combined chemotherapeutic products for synergy, mainly practiced in human medicine, is gaining importance in livestock. A trial to evaluate efficacy of VERYL®, containing diminazene diaceturate (3.5 mg/kg body weight) and levamisole chloride (5 mg/kg body weight) for the control of GINs in cattle, was conducted at KALRO-VSRI Muguga, Kenya, between June and August 2016. Thirty-eight cattle aged between 6 and 12 months, naturally infected with GINs, were randomly allocated into two groups; a treatment group received VERYL® intra-muscularly at 10 mL/100 kg bwt and a control group which received Veriben® (Diminazene aceturate) at 3.5 mg/kg bwt. Faecal egg counts (FECs), coproculture, packed cell volume (PCV) and local tolerance at the injection site were measured during the study. FECs were comparable between the treatment and control groups at day 0. However, treatment of cattle with VERYL significantly (p < 0.001) reduced FECs by day 7 and sustained to day 21 post-treatment. Coproculture results for the treatment and control groups revealed presence of Haemonchus, Cooperia, Ostertagia, Trichostrongylus and Oesophagostomum species. Cattle treated with VERYL® had a significant (p < 0.05) reduction in larval recoveries compared to the control group. VERYL® had minimal adverse effects which cleared after a short while and is thus recommended for controlling GINs in cattle.

Seroepidemiological survey of Taenia saginata cysticercosis in Kenya.

A sero-epidemiological study of Taenia saginata cysticercosis was carried out to determine the prevalence and distribution of the infection in three provinces of Kenya. Serum samples and meat inspection records were collected from cattle at slaughter at export and district abattoirs. Cattle origin and the presence of T. saginata cysticerci were noted as was the prevalence of other helminths such as Echinococcus granulosus and Fasciola gigantica. Serum samples were screened for circulating parasite antigen using a monoclonal antibody-based enzyme-linked immunosorbent assay (Ag-ELISA) and for ante-parasite antibody by indirect ELISA (Ab-ELISA). Eighty per cent of the sera were collected from cattle from the Rift Valley Province of Kenya. The prevalence of T. saginata cysticercosis and the other helminth infections varied between districts and was particularly high in Narok. Animal husbandry practices in arid areas such as Narok may be particularly conducive to transmission. The potential value of the Ag-ELISA for use in sero-epidemiological studies was verified by this study. It detected at least twice as many cases as T. saginata cysticercosis as meat inspection and, of the three methods investigated, was considered the most valuable.

Epidemiology of parasitic gastrointestinal nematode infections of ruminants on smallholder farms in central Kenya.

In order to establish the infection pattern with gastrointestinal nematodes in ruminants in the central Kenya highlands, a study was carried out in 58 smallholder farms. The study involved monthly faecal examinations from sheep, goats and cattle and pasture sampling from eight communal grazing areas. Each month, six Dorper worm-free tracer lambs were introduced and four locally grazed cross-bred sheep were purchased for parasite recovery. The mean faecal egg counts (FEC) for cattle were low throughout the study period, whereas those for sheep and goats showed a seasonal pattern with high levels of infection occurring during the two main rainy seasons, especially in March, April and October. There were significant differences in egg counts over time and among farms. Haemonchus contortus was the most prevalent nematode in the tracer lambs whereas the previously exposed locally grazed sheep had significantly lower numbers of H contortus but significantly higher numbers of Trichostrongylus species The highest levels of infection in the tracer lambs occurred in November 1995 and January, May and June 1996. Based on this study, it is now possible to explore the possibility of using strategic treatments for the control of parasitic gastroenteritis in this area of Kenya.

Prevalence of parasites of the local scavenging chickens in a selected semi-arid zone of Eastern Kenya.

A study to identify and estimate the prevalence of parasites of local chickens in a semi arid area of Kenya was conducted between March 2005 and August 2006. Three hundred and sixty (360) local chickens purchased from Yathui division of Machakos were examined. Of those, 93.3% had helminths. Nematodes were recovered in 268 (74.4%) chickens whereas 245 (68.1%) had cestodes. Tetrameres americana (37.7%), Ascaridia galli (33.3%) and Heterakis gallinarum (22.8%) were the most important nematode species identified. Raillietina echinobothrida (33.3%) and Davainea proglottina (19.4%) were the two most important cestode species identified. Two coccidia species, namely Eimeria necatrix (6.7%) and E. tenella (16.7%) were isolated and identified as per location in the digestive system. Important ectoparasites identified included Echidnophaga gallinacea (76.7%), Menacanthus stramineus (79.4%) and Dermanyssus gallinae (60.0%). Endo-parasites (helminths and coccidia) occurred in significantly (p<0.05) higher frequencies during the wet season than during the dry season. On the contrary, ecto-parasites were significantly (p<0.05) more fequent during the dry season. Male chickens generally exhibited increased odds for the occurrence of parasites than female birds. Further investigations are required to establish a plausible explanation for this. Overall, parasitism was a big constraint to chicken productivity in the study area. Urgent integrated parasite control approaches should be initiated to address parasitism in chickens in the Yathui cluster.

The prevalence and economic significance of Fasciola gigantica and Stilesia hepatica in slaughtered animals in the semi-arid coastal Kenya.

Fasciola gigantica and Stilesia hepatica constrain ruminant productivity. The prevalence and economic losses caused by F. gigantica and S. hepatica in the ruminant production systems of Taveta division of Kenya were estimated in a retrospective appraisal of the slaughter records on the total number of animals slaughtered and livers condemned over the period 1989 to 2004. Only liver condemnations based on infestation by F. gigantica and S. hepatica were considered for purposes of this study. Liver condemnation rates differed significantly between bovines, caprines and ovines (p < or = 0.05) for F. gigantica (26%, 6.6% and 5.2%, respectively) and for S. hepatica (0.4%, 22% and 28%, respectively). The total loss through condemnation of both F. gigantica and S. hepatica infested livers was 4,408,272 KES (Kenyan shillings) (US dollars 72,272). The proportion of loss in bovines, caprines and ovines, was 76%, 17% and 7%, respectively. Fasciolosis contributed 3505410 KES (79.5%) and S. hepatica infestation 903,210 KES (20.5%) to the total losses due to liver condemnations. The authors feel strongly that there is a need for more work on the two parasites using live animals to determine the prevalence in animals of various ages, species and breeds and the economics of disease control at farm level.

Diagnosis of Stilesia hepatica infection in sheep.

A technique for examining faecal samples for Stilesia hepatica proglottids was assessed for diagnosis of this infection in live sheep. It detected infection in 67% of all the sheep that were confirmed infected by examining the livers during meat inspection and in 63% of sheep from a farm with a history of up to 100% infection rate at slaughter. It is 100% specific since it relied on the morphological identification of S. hepatica proglottids, which are characteristic. In addition it detected Avitellina centripunctata proglottids.