Seasonal Prevalence and Molecular Identification of ThermophilicCampylobacter from Chicken, Cattle, and Respective DrinkingWater in Kajiado County, Kenya

Abstract

Thermophilic Campylobacter species are a leading cause of human gastroenteritis throughout the world and have been implicatedin reproductive disorders (abortion), mastitis, enteritis, and/or diarrhoea in livestock. A cross-sectional survey was conducted inKajiado County to determine prevalence, seasonality, and molecular detection of thermophilic Campylobacter species (withemphasis on C. jejuni, C. coli, and other thermophilic Campylobacter species) in chicken, cattle, and respective pooled drinkingwater. A total of 457 samples comprising 265 cattle rectal swabs, 142 chicken cloacal swabs, and 50 trough water samples werecollected from 55 randomly selected smallholder farms. Individual samples were subjected to standard techniques for isolationand biochemical tests, followed by singleplex polymerase chain reaction (sPCR) assays for identification and confirmation ofgenus and species. Overall, thermophilic Campylobacter prevalence was 35.4% (95% confidence interval (95% CI) 31.0–39.8),with C. jejuni dominating at 55.6% (95% CI 47.9–63.3%) over C. coli in all sample types. The highest thermophilic Cam-pylobacter prevalence was observed in cloacal swabs of live chicken at 44.4% (95% CI 36.2–52.6%), followed by rectal swabs fromlive cattle at 30.9% (95% CI 25.3–36.5%). Water samples from cattle drinkers/trough were found to be contaminated at 34%(95% CI 20.9–47.1%). The isolation rate was higher in cattle under the confinement system (44.3%) (95% CI 36.1–52.5%) thanin those under the free-roaming grazing system. Thermophilic Campylobacter species were isolated in both seasons, with higherprevalence (39.8% (95% CI 33.6–45.9)) recorded during rainy and cold season in all sample types except for water. There wassignificant (P < 0.05) association between season and thermophilic Campylobacter occurrence, even though there were nostatistical differences in the prevalence values across the two seasons. Results of this study demonstrate that cattle, chicken, andrespective drinking water harbour potentially pathogenic thermophilic campylobacters, with C. jejuni being widely distributedamong farms. It is possible that seasonal variations and cattle confinement result in differences in thermophilic Campylobactercarriage. Further epidemiological and phylogenetic studies comparing distribution of thermophilic Campylobacter spp. isolates inlivestock, environmental, and human samples are recommended to establish source attribution to reduce the impact of resultantdiseases for the wellbeing of public and livestock.