Prevalence of Campylobacter and Salmonella in African food animals and meat: A systematic review and meta-analysis

• Published in: International journal of food microbiology Vol. 315; p. 108382
• Main Authors: Thomas, Kate M., de Glanville, William A., Barker, Gary C., Benschop, Jackie, Buza, Joram J., Cleaveland, Sarah, Davis, Margaret A., French, Nigel P., Mmbaga, Blandina T., Prinsen, Gerard, Swai, Emmanuel S., Zadoks, Ruth N., Crump, John A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 16-02-2020; Elsevier BV; Elsevier Science Publishers
• Subjects: Africa; Africa - epidemiology; Animal products; Animals; Beef cattle; Campylobacter; Campylobacter - isolation & purification; Campylobacter Infections - epidemiology; Campylobacter Infections - microbiology; Campylobacteriosis; Cattle; Contamination; Feathers; Feces - microbiology; Food; Food animals; Food contamination; Food Contamination - analysis; Food Microbiology; Food production; Food safety; Humans; Infections; Meat; Meat - microbiology; Meat production; Meat Products - microbiology; Meta-analysis; Organs; Pathogens; Poultry; Poultry - microbiology; Prevalence; Regression analysis; Reviews; Salmonella; Salmonella - isolation & purification; Salmonella Infections, Animal - epidemiology; Salmonellosis; Sheep; Swine; Africa; Salmonella; Food safety; Prevalence; Food animals; Africa; Campylobacter
• ISSN: 0168-1605; 1879-3460; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2019.108382

Campylobacter and Salmonella, particularly non-typhoidal Salmonella, are important bacterial enteric pathogens of humans which are often carried asymptomatically in animal reservoirs. Bacterial foodborne infections, including those derived from meat, are associated with illness and death globally but the burden is disproportionately high in Africa. Commercial meat production is increasing and intensifying in many African countries, creating opportunities and threats for food safety.
Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, we searched six databases for English language studies published through June 2016, that reported Campylobacter or Salmonella carriage or infection prevalence in food animals and contamination prevalence in food animal products from African countries. A random effects meta-analysis and multivariable logistic regression were used to estimate the species-specific prevalence of Salmonella and Campylobacter and assess relationships between sample type and region and the detection or isolation of either pathogen.
Seventy-three studies reporting Campylobacter and 187 studies reporting Salmonella across 27 African countries were represented. Adjusted prevalence calculations estimate Campylobacter detection in 37.7% (95% CI 31.6–44.3) of 11,828 poultry samples; 24.6% (95% CI 18.0–32.7) of 1975 pig samples; 17.8% (95% CI 12.6–24.5) of 2907 goat samples; 12.6% (95% CI 8.4–18.5) of 2382 sheep samples; and 12.3% (95% CI 9.5–15.8) of 6545 cattle samples. Salmonella were detected in 13.9% (95% CI 11.7–16.4) of 25,430 poultry samples; 13.1% (95% CI 9.3–18.3) of 5467 pig samples; 9.3% (95% CI 7.2–12.1) of 2988 camel samples; 5.3% (95% CI 4.0–6.8) of 72,292 cattle samples; 4.8% (95% CI 3.6–6.3) of 11,335 sheep samples; and 3.4% (95% CI 2.2–5.2) of 4904 goat samples. ‘External’ samples (e.g. hide, feathers) were significantly more likely to be contaminated by both pathogens than ‘gut’ (e.g. faeces, cloaca) while meat and organs were significantly less likely to be contaminated than gut samples.
This study demonstrated widespread prevalence of Campylobacter species and Salmonella serovars in African food animals and meat, particularly in samples of poultry and pig origin. Source attribution studies could help ascertain which food animals are contributing to human campylobacteriosis and salmonellosis and direct potential food safety interventions.
•Campylobacter prevalence data was compiled from 14 African countries.•Salmonella prevalence data was compiled from 27 African countries.•Campylobacter and Salmonella were most prevalent in poultry and pig samples.•C. jejuni was the most predominant Campylobacter species except in pigs where C. coli predominates.•S. enterica serovar Typhimurium was the most commonly identified Salmonella serovar.