Prevalence of and Awareness of the Risks Associated with Antimicrobial Drug Residues in Edible Tissues of cattle and Pigs in Enugu State, Nigeria

ABSTRACT 

This study was aimed at determining the prevalence of and awareness of health risks associated with antimicrobial residues (AMRs) in edible tissues of cattle and pigs slaughtered for human consumption in Enugu State. In the first phase, the awareness of public health problems associated with consumption of animal tissues containing AMRs and compliance to specified withdrawal period (WP) by livestock farmers and veterinary practitioners were determined. This was carried out using a total of 200 copies of a structured questionnaire designed to obtain information on the status of antimicrobial drug use, observance of WP and awareness of public health problems associated with consumption of animal products containing AMRs. A minimum of sixty (60) copies of the questionnaire were distributed to willing respondents in each of the three senatorial zones of the state. One hundred and eighty-two (182) copies of completed questionnaire were recovered and the responses collated and analyzed. The second phase of the study which was the determination of the prevalence of AMRs in edible tissues (kidney, liver and muscle) of cattle and pigs in the study area was carried out using Premi® test kit. A total of 285 tissue samples (180 from cattle and 105 from pigs) were randomly collected from animals slaughtered in Nsukka, Akwata and 9th Mile slaughter houses. Chi-square (χ 2 ) test of independence was used to determine the strength of association between educational level of the respondents and observance of withdrawal period, and awareness of public health risks associated with consumption of animal products containing AMRs. Job experience and observance of withdrawal period were also compared among the respondents using the same test. Furthermore, the strength of association in the occurrence of AMRs among the species (cattle and pigs) and organs in each of the species were also determined. All the respondents (100%) had used at least one antimicrobial drug in food animals between January and April, 2011 but only 25.99% of the respondents administered these drugs based on veterinary prescription. The antimicrobial drugs used in food animals and the percentage of respondents that utilized them were oxytetracycline (23.44%), penicillin (21.16%), streptomycin (16.81%) tylosin (11.62%), sulphadimidines (10.17%), enrofloxacin (8.92%) and chloramphenicol (7.88%). Only 33.12% of the respondents administered the drugs for chemotherapeutic purposes while the rest (66.88%) used the drugs for non-chemotherapeutic purposes (prophylaxis or growth promotion). Irrespective of educational levels, majority (84.68%) of the livestock farmers were not aware of the public health risks associated with consumption of animal products containing AMRs. All the 12 veterinary practitioners surveyed were aware of the health problems associated with the consumption of AMRs in edible tissues. Majority of the livestock farmers (88.37%) and some (30.19%) of the veterinary practitioners do not observe WP. There were significant association (p0.05) existed between job experience and observance of WP in both the livestock farmers and veterinary practitioners. The prevalence of AMRs was significantly higher (p0.05) in the organ (kidney, liver and muscle) distributions of AMRs in both cattle and pigs. The general public in the study area are at risk of the health hazards associated with consumption of animal tissues containing AMRs. Withdrawal period should be observed and strict enforcement of veterinary drug laws in Nigeria is recommended to safeguard human health.