Drug residues in foods of animal origin are drugs and their metabolites which are found in edible tissues and milk of animals following their medication with specific drugs whose prescribed withdrawal period are not observed. Chloramphenicol (CAP) residues in the food chain are potential hazards to public health. Such hazards include: allergy, antibacterial resistance, carcinogenicity, genotoxicity, aplastic anemia and leukemia. Globally, aplastic anemia affects 1 in 10,000 to 50,000 patients receiving a typical course of CAP therapy and about 280,000 patients are susceptible to the development of aplastic anemia in Nigeria.9,10 CAP has therefore been banned globally by FAO/WHO and considered a drug of zero-tolerance in food-producing animals. This study was carried out to determine the occurrence of CAP residues in chicken eggs in the FCT and to assess the usage and awareness of its ban amongst poultry farmers.
A cross-sectional survey using structured questionnaires was conducted on poultry farmers and a survey of commercial chicken eggs from poultry farms and government owned markets in FCT, Nigeria was also carried out using CAP ELISA kits to test for the presence of CAP in eggs.
Frequencies and proportions were obtained by univariate analysis and odds ratios and Fischer‟s exact p-values at 95% confidence intervals were also obtained using OpenEpi and EpiInfo version 3.5.3 softwares.
Of the 57 questionnaire respondents, 30 (52.6%) were farm managers out of which 48 (84.2%) were males, and 27 (47.4%) were between ages 36-50 years. Pooled egg samples (10 eggs make a sample, n=288 i.e. 2880 eggs) were analyzed using CAP ELISA kits and 20 (7%) of the samples tested positive for CAP residues. Poultry farmers use both human (8.8%) and veterinary drug preparations containing CAP (43.9%) on their birds. Most poultry farmers (71.9%) were not aware that CAP is not recommended for use in food producing animals. There is a strong association (OR=14.8) between human CAP and its detection by ELISA test (Fischer‟s Exact P<0 .05="" are="" attendants="" aware.="" aware="" ban="" be="" cap="" exact="" fitscher="" less="" likely="" more="" of="" p="0.4)" poultry="" s="" span="" the="" to="" veterinarians="" while="">
There is an influx of CAP residue-containing eggs from within FCT and also from other States into FCT with 7% prevalence. Poultry farmers using both human and veterinary CAP preparations were not aware of its ban for use in food-producing animals. There is therefore the need for drug residue surveillance and education of poultry farmers on the prohibition of CAP in food animals and its hazards to public health.
CHAPTER ONE – INTRODUCTION
Drug residues in foods of animal origin are drugs and their metabolites which are found in edible tissues and milk of animals following their medication with specific drugs whose prescribed withdrawal period are not observed. 1, 2 Drug residues eventually make their way to the food chain where they can potentially pose a risk to human health. Such health problems include development of allergic reactions, emergence of multiple resistant strains of pathogenic bacteria, development of cancer and mutations, aplastic anemia and leukemia in humans.3 This has resulted in the global ban of the use of chloramphenicol in Veterinary Medicine to non-food use due to potential public health risks posed by its traces in edible tissues and was therefore considered a drug with an established zero-tolerance.4
Chloramphenicol (CAP) was first isolated in 1947 from the soil bacterium Streptomyces venezuelae, and synthetic production began in 1949.5 Due to its outstanding antibacterial properties, CAP is an often used antibiotic in the production of milk, meat and eggs. It is an inexpensive broad-spectrum antibiotic recommended for the treatment of salmonella infections and for the prevention of secondary infections associated with chronic respiratory disease and blue comb in poultry.6 It is well absorbed by both oral and parenteral routes. CAP usually acts as a bacteriostatic, but at higher concentrations or against some very susceptible organisms it can be bactericidal. It is used in the treatment of human infection with Salmonella typhi and other forms of salmonellosis and other threatening infections of the central nervous system and respiratory tract...