Abusive use of antibiotics in poultry farming in Cameroon and the public health implications.

The types and methods of use of antibiotics in poultry farms in Cameroon, residual levels and potential microbial resistance were determined. A questionnaire-based survey identified the different antibiotics used and high-performance liquid chromatography (HPLC) was used to determine residual levels of antibiotics. Pathogens were isolated, identified by use of commercial API kits and minimum inhibition concentration (MIC) was determined. Oxytetracyclin, tylocip and TCN (oxytetracycline, chloramphenicol and neomycin) were the most frequently used antibiotics. Antibiotics screened by HPLC were chloramphenicol, tetracycline and vancomycin. All of them except vancomycin were detected, and the concentration of these antibiotics was higher than the maximum residual limits (MRL) set by regulatory authorities. No residues of various antibiotics were found in egg albumen or yolk. The concentration of tetracycline was significantly higher in liver (150 ± 30 µg/g) than in other tissues. Foodborne pathogens, including Salmonella spp., Staphylococcus spp., Listeria spp., Clostridium spp. and Escherichia spp., were identified. Most of the pathogens were resistant to these various antibiotics tested. These findings imply the need for better management of antibiotic use to control sources of food contamination and reduce health risks associated with the presence of residues and the development of resistant pathogens by further legislation and enforcement of regulations on food hygiene and use of antibiotics.

[Effect of Onchocerca volvulus infestation on plasma vitamin A concentration in school children in a rural region of Cameroon]. / Influence de l'infestation par Onchocerca volvulus sur le taux sérique de vitamine A des enfants scolariss en zone rurale du Cameroun.

Vitamin A deficiency is known to be associated with immune dysfunction and common childhood infections. However, little is known about the relationship between vitamin A deficiency and onchocerciasis in children. The aim of this study was to determine the prevalence of vitamin A deficiency and to investigate the relationship between vitamin A status and onchocerciasis. A total of 231 children, aged 6 to 15 years, were randomly selected between March 1995 and April 1996 at Yambassa and Balamba (central province of Cameroon). They were examined: we determined their vitamin A status and whether they had onchocerciasis. We diagnosed onchocerciasis by skin biopsy and the detection of antibodies against Onchocerca volvulus in the blood. We found that 101 of the 231 children examined (43.73%) had palpable nodules and/or microfilariae and the remaining 130 (56.27%) had been exposed to the parasite but had no clinical signs of infestation. Some children tested negative for skin microfilariae but positive by ELISA. Thus, 197 (85.28%) children were found to be infested with O. volvulus (group A) and the remaining 34 (14.72%) were found to have been exposed to the parasite but to have no clinical signs of onchocerciasis (group B). Plasma vitamin A concentrations were marginal, with concentrations below 0.7 mumol/l (20 mug/dl) recorded for 82.25% of the subjects. Children with onchocerciasis were more likely to have low vitamin A status. The mean plasma vitamin A concentration of infested children (0.52 +/- 0.14 mumol/l) was significantly lower (p < 0.05) than that of the children exposed but not infested. The parasite, O. volvulus, uses the vitamin A present in host tissues during its development, leading to a decrease in plasma retinol concentration.