Antibiotic Residues in Foods of Animal Origin in Cameroon: Prevalence, Consumers' Risk Perceptions, and attitudes.

The use of antibiotics in food animals and the nonobservance of the withdrawal period might result in the accumulation and persistence of residues in foods. The contamination of foods by antibiotic residues might induce health risks including allergy, gastrointestinal dysbiosis, antimicrobial resistance, and cancer to consumers. Therefore, this study was initiated to investigate the presence of antibiotic residues in raw eggs, raw milk, and beef collected at the wholesale and retail points in the three major cities of Cameroon and consumers' perceptions of the risk of antibiotic residues in foods. Qualitative antibiotic residue kits (PremiTest® and Delvotest®) were used to screen 407 samples of foods collected in markets of three towns (Ngaoundéré, Yaoundé, and Douala) in Cameroon. A structured questionnaire was used to evaluate the knowledge and attitudes of 1462 consumers toward microbial drug residues in foods of animal origin. Prevalence of residues of 70.55%, 17.39%, and 69.63% for beef, eggs, and milk, respectively, was observed. More than 1/3 of the respondents believed that the consumption of contaminated foods with antibiotic residues is a risk to their health and thought that allergies and intoxication they often experience are related to the consumption of contaminated foods. Most of them showed their willingness to pay more to acquire quality foods, free from antibiotic residues.

Co-Administration of Adjuvanted Recombinant Ov-103 and Ov-RAL-2 Vaccines Confer Protection against Natural Challenge in A Bovine Onchocerca ochengi Infection Model of Human Onchocerciasis.

Onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, is a neglected tropical disease mainly of sub-Saharan Africa. Worldwide, an estimated 20.9 million individuals live with infection and a further 205 million are at risk of disease. Current control methods rely on mass drug administration of ivermectin to kill microfilariae and inhibit female worm fecundity. The identification and development of efficacious vaccines as complementary preventive tools to support ongoing elimination efforts are therefore an important objective of onchocerciasis research. We evaluated the protective effects of co-administering leading O. volvulus-derived recombinant vaccine candidates (Ov-103 and Ov-RAL-2) with subsequent natural exposure to the closely related cattle parasite Onchocerca ochengi. Over a 24-month exposure period, vaccinated calves (n = 11) were shown to acquire infection and microfilaridermia at a significantly lower rate compared to unvaccinated control animals (n = 10). Furthermore, adult female worm burdens were negatively correlated with anti-Ov-103 and Ov-RAL-2 IgG1 and IgG2 responses. Peptide arrays identified several Ov-103 and Ov-RAL-2-specific epitopes homologous to those identified as human B-cell and helper T-cell epitope candidates and by naturally-infected human subjects in previous studies. Overall, this study demonstrates co-administration of Ov-103 and Ov-RAL-2 with Montanide™ ISA 206 VG is highly immunogenic in cattle, conferring partial protection against natural challenge with O. ochengi. The strong, antigen-specific IgG1 and IgG2 responses associated with vaccine-induced protection are highly suggestive of a mixed Th1/Th2 associated antibody responses. Collectively, this evidence suggests vaccine formulations for human onchocerciasis should aim to elicit similarly balanced Th1/Th2 immune responses.

Cross-Sectional Survey of Prophylactic and Metaphylactic Antimicrobial Use in Layer Poultry Farming in Cameroon: A Quantitative Pilot Study.

An evaluation of the patterns of antimicrobial use in livestock can help understand the increasing level of antimicrobial resistance worldwide. This study aimed at evaluating antimicrobial usage in modern layer poultry farms in the West Region of Cameroon. In this light, 70 layer poultry farms and 4 veterinary pharmacies were surveyed. Data on antimicrobial use were collected through interviews using a quantitative-frequency questionnaire and consultation of medical records. The four veterinary pharmacies sold a total of 2.8 tons of antimicrobials (active ingredients) during 2011. At the level of farms, 297 kg of antimicrobials (active ingredients) were used in the 50 layer poultry farms surveyed. Tetracycline, sulfonamides, quinolones, and ß-lactams (aminopenicillins) were the most sold and used drugs in layer farms. As for treatment indication, metaphylactic (58.1%) and prophylactic (41.9%) treatments were the most observed practices, and nearly all (99%) treatments were administered per os as remedies to respiratory (33.4%) and digestive (24.7%) tract symptoms. Overall, 78.2% of antimicrobials sold in pharmacies and 67.3% used in the farms belonged to the class of critically important antimicrobials of the WHO categorization of antimicrobials according to their importance to human medicine. Doxycycline, sulfonamide, ampicillin, and streptomycin, which have been banned for layer poultry in the production of eggs for human consumption, were still used in Cameroon. The treatment incidences based on the used daily dose (TIUDD) and animal daily dose (TIADD) were 11.59 and 10.45, respectively. In regard to dosage correctness based on the UDD/ADD ratio, aminoglycosides (100%), macrolides (90.6%), and tetracyclines (74.5%) were the most underdosed, while trimethoprim sulfonamides (45.8%) and ß-lactams (35.7%) were overdosed. This study highlights an irrational antimicrobial usage in layer poultry farms. Regulation of the use of antimicrobials and the education of farmers on adequate antimicrobial use are essential to preserve the effectiveness of drugs in both humans and animals.

African swine fever in the northern regions of Cameroon: seroprevalence survey and spatiotemporal analysis of outbreaks from 2010 to 2017.

The present study was carried out to establish the spatiotemporal distribution of ASF between 2010 and 2017 in the Adamawa, North, and Far North regions of Cameroon. A retrospective study with data relating to the northern regions from epidemiological reports from target organizations in Cameroon was used to analyze outbreaks of ASF from 2010 to 2016. A prospective study consisting of risk factor analysis and serological investigation of anti-ASF antibodies and ASF RT-PCR antigen detection test in pig farms in the study regions with clinical suspicion of ASF was carried out in 2017. During the period 2010 to 2016, a total of 53 ASF outbreaks were reported and confirmed in the three northern regions of Cameroon and involved 4905 pigs (2232 deaths and 2673 slaughtered for sanitary measures). The seroprevalence for the 2017 serology survey was 5.23% (95% CI [3.57-6.89]) at the individual and 10.81% (95% CI [6.34-15.28]) at herd level. Region, management of farms system, on-farm slaughter by the owner (OR = 4.60; 95% CI [0.34-46.20]; p = 0.014), and selling of animals to community or to butchers (OR = 4.82; 95% CI [0.51-62.15]; p = 0.010) had significant effect on individual level seropositivity of ASF. The viral antigen was not detected by PCR. This study showed that ASF cases have decreased significantly in the northern regions of Cameroon following the epizootic 2010 outbreaks. The findings predict a better future for the pork farming in the regions through the enforcement of strategic measures.

Antimicrobial resistance from a one health perspective in Cameroon: a systematic review and meta-analysis.

BACKGROUND: Antimicrobial resistance (AMR) is widely acknowledged as a global health problem, yet in many parts of the world its magnitude is not well elucidated. A baseline assessment of the AMR prevalence is a priority for implementation of laboratory-based AMR surveillance This review, focused on a One health approach, aimed at describing the current status of AMR in Cameroon. METHODS: PubMed, Google Scholar and African Journals Online databases were searched for articles published in English and French in accordance with the PRISMA guidelines. Retrieval and screening of article was done using a structured search string with strict inclusion/exclusion criteria. Free-text and grey literature were obtained by contacting the authors directly. The pooled prevalence and 95% confidence intervals were calculated for each pathogen-antibiotic pairs using random-effects models. RESULT: Amongst 97 full-text articles reviewed, 66 met the eligibility criteria. The studies originated from the Centre (24; 36.4%), South-West (16; 24.2%), West (13; 19.7%), Littoral (9; 13.6%) and other (4; 6.1%) regions of Cameroon. These studies reported AMR in human (45; 68.2%), animals (9; 13.6%) and the environment (12; 18.2%). Overall, 19 species of bacteria were tested against 48 antibiotics. These organisms were resistant to all classes of antibiotics and showed high levels of multidrug resistance. Escherichia coli, Klebsiella pneumoniae and Staphylococcus spp were reported in 23, 19 and 18 of the human studies and revealed multidrug resistance (MDR) rates of 47.1% [95% CI (37.3-57.2%)], 51.0% [95% CI (42.0-59.9)] and 45.2% [95% CI (38.0-54.7)], respectively. Salmonella spp was reported in 6 of the animal studies and showed a MDR rate of 46.2% [95% CI (39.2-53.5%)] while Staphylococcus spp in 8 of environment studies showed MDR rate of 67.1% [95% CI (55.2-77.2%)]. CONCLUSION: This review shows that resistance to commonly prescribed antibiotics in Cameroon is high. The findings emphasize the urgent need to address gaps in the standardization of AMR diagnostics, reporting and use of available information to optimize treatment guidelines for the arsenal of antibiotics. Effective AMR surveillance through continued data sharing, large-scale collaboration, and coordination of all stakeholders is essential to understand and manage the AMR national burden.