Bacterial contamination of Kale (Brassica oleracea acephala) along the supply chain in Nairobi and its environment

Objective: To assess the microbiological safety of kale (Brassica oleracea Acephala) produced from farms and those sold at the markets with special focus on coliforms, E.coli and Salmonella.Design: A cross sectional study.Setting: Peri-Urban farms (in Athi River, Ngong and Wangige), wet markets (in Kawangware, Kangemi and Githurai), supermarkets and high-end specialty store both within Nairobi city.Results: Mean coliform count on vegetables from farms were 2.6x105 ±5.0x105 cfu/g while those from the wet markets were 4.6x106 ±9.1x106 cfu/g, supermarkets, 2.6x106 ±2.7x106 and high-end specialty store 4.7x105 ±8.9x105. Coliform numbers obtained on kales from the wet markets and supermarkets were significantly higher (p<0.05) compared to those from farms, while kale samples purchased from high- end specialtystore had similar levels of coliform loads as those from the farms. E. coli prevalence in the wet markets, supermarkets and high-end specialty store were: 40, 20 and 20%, respectively. Salmonella was detected on 4.5 and 6.3% of samples collected from the farms in Wangige and wet market in Kawangware, respectively. Fecal coliforms in water used on farms (for irrigation) and in the markets (for washing the vegetables) exceeded levels recommended by World Health Organization (WHO) of 103 organisms per 100 milliliter while Salmonella was detected in 12.5% of washing water samples collected from Kangemi market.Conclusion: Poor cultivation practices and poor handling of vegetables along the supply chain could increase the risk of pathogen contamination thus puting the health of the public at risk, therefore good agricultural and handling practices should be observed

Randomized controlled field trial to assess the immunogenicity and safety of rift valley fever clone 13 vaccine in livestock

BACKGROUND:Although livestock vaccination is effective in preventing Rift Valley fever (RVF) epidemics, there are concerns about safety and effectiveness of the only commercially available RVF Smithburn vaccine. We conducted a randomized controlled field trial to evaluate the immunogenicity and safety of the new RVF Clone 13 vaccine, recently registered in South Africa. METHODS:In a blinded randomized controlled field trial, 404 animals (85 cattle, 168 sheep, and 151 goats) in three farms in Kenya were divided into three groups. Group A included males and non-pregnant females that were randomized and assigned to two groups; one vaccinated with RVF Clone 13 and the other given placebo. Groups B included animals in 1st half of pregnancy, and group C animals in 2nd half of pregnancy, which were also randomized and either vaccinated and given placebo. Animals were monitored for one year and virus antibodies titers assessed on days 14, 28, 56, 183 and 365. RESULTS:In vaccinated goats (N = 72), 72% developed anti-RVF virus IgM antibodies and 97% neutralizing IgG antibodies. In vaccinated sheep (N = 77), 84% developed IgM and 91% neutralizing IgG antibodies. Vaccinated cattle (N = 42) did not develop IgM antibodies but 67% developed neutralizing IgG antibodies. At day 14 post-vaccination, the odds of being seropositive for IgG in the vaccine group was 3.6 (95% CI, 1.5 - 9.2) in cattle, 90.0 (95% CI, 25.1 - 579.2) in goats, and 40.0 (95% CI, 16.5 - 110.5) in sheep. Abortion was observed in one vaccinated goat but histopathologic analysis did not indicate RVF virus infection. There was no evidence of teratogenicity in vaccinated or placebo animals. CONCLUSIONS:The results suggest RVF Clone 13 vaccine is safe to use and has high (>90%) immunogenicity in sheep and goats but moderate (> 65%) immunogenicity in cattle

Carrier status for Listeria monocytogenes and other Listeria species in free range farm and market healthy indigenous chickens and ducks

Background: Listeria organisms are documented to be zoonotic; one of the sources of infection is the domestic fowl where it could occur as in apparent infection. The carriage of Listeria monocytogenes and other Listeria in indigenous birds has not been documented in Kenya. Objective: To establish whether healthy looking indigenous chickens and ducks could be carriers of Listeria monocytogenes and other Listeria species. Design: Field survey of indigenous chickens and ducks in three districts of Kenya. Setting: Embakasi and Dagoreti divisions in Nairobi district; Athi river division in Machakos district; and Ngong division in Kajiado district, in Kenya. Subjects: One hundred and thirty six indigenous chickens and 39 ducks reared under free range scavenging system in Nairobi, Machakos and Kajiado districts, in Kenya, were sampled. Methods: In surveying the birds, the cloacal and pharyngeal swabs were taken from each bird separately using sterile cotton - tipped applicator swabs. The swabs in saline were transported in a coolbox to the laboratory for bacterial isolation and characterization. Interventions: None (only compared farmed and the traded birds). Main outcome measures: Isolation of Listeria species and pathogenicity of Listeria isolates. Results: Two Listeria monocytogenes and seven other Listeria species were recovered from the oropharyngeal swab samples of farm and market chickens but none from respective cloacal swabs. No Listeria was recovered from either oropharyngeal or cloacal swabs of farmed ducks and slaughter chickens. Traded chickens yielded more Listeria isolates as compared to farmed chickens. Conclusion: This study shows that indigenous chickens in Kenya are carriers of Listeria monocytogenes and other Listeria species. East African Medical Journal Vol.81(10) 2004: 529-53

Sensitivity of Listeria species, recovered from indigenous chickens to antibiotics and disinfectants

Background: Resistance of bacteria to antibiotics and disinfectants has been reported widely in the world. Listeria monocytogenes is no exception, although normally it tends to be variably sensitive to many antibiotics and disinfectants. Objectives: To assess the susceptibility of Listeria isolates recovered from indigenous chickens to commonly used antimicrobials. Design: Nine Listeria isolates recovered from village chickens were tested for sensitivity to commonly used antibiotics and disinfectants and compared with Listeria monocytogenes type strains (L028 and DGH), Staphylococcus aureus NCTC 6571 and Escherichia coli ATCC 25922. Subjects: Nine Listeria isolates. Interventions: None. Main outcome measures: Susceptibility to eight antibiotics and seven disinfectants. Results: The nine Listeria isolates were sensitive to gentamycin (100%), kanamycin (88.9%), tetracycline (77.8%), cotrimoxazole (66.7%), chloramphenicol (66.7%) and resistant to ampicillin, augmentin and cefuroxime. There was no difference between the antibiotic sensitivity to the various Listeria isolates and Listeria monocytogenes type strains (P>0.05). The isolates were sensitive to disinfectants; A (100%), B (88.9 %), D (77.8%), E (77.8%) but resistant to, CF, and G. There was significant difference between the resistance of Listeria isolates to the various disinfectants at the varied dilutions and the resistance at the recommended user - dilution (P< 0.00293). Conclusion: This study has shown that some of the Listeria isolates were resistant to most common antimicrobial agents except gentamycin and disinfectant A. Hence the need to consider this resistance pattern for effective treatment and control of listeriosis. East African Medical Journal Vol.81(10) 2004: 534-53

A case of newcastle disease in parrots in Nairobi, Kenya

No Abstract Bulletin of Animal Health and Production in Africa Vol. 55 (4) 2007: pp. 292-29

Newcastle disease virus and antibody levels in matched sera, ovules and mature eggs of indigenous village hens

In this study, one hundred and thirty three non - vaccinated village hens in lay were tested for carriage of Newcastle disease virus and presence of antibody against the virus in sera, ovules and eggs. Blood was obtained from the hens through wing venipuncture while matched ovules and mature eggs were taken from the oviducts. Cloacal and oropharyngeal swabswere collected from each hen for virus isolation. Haemagglutination inhibition assay was performed for all sera and egg yolk samples. Protective serum antibody titres of ≥3 (log2) were recorded in 5.3% of the naturally exposed, indigenous village hens. Antibody titers to Newcastle disease virus in the yolks were higher than in their sera (230.08 ± 40.05; 1.56 ± 0.74 for egg yolk and sera, respectively) (