Agroecology influences Salmonella food contamination with high exposure risk among children in Karamoja sub-region: A high diarrhoea prevalent locality in Uganda

Uganda is among low-income countries where Salmonella induced diarrhoea still contributes significantly to children under five years (CUF) mortality. Karamoja, a sub-region characterised by three agroecologies (pastoral: PE; agro-pastoral: APE; agricultural: AE), is a geographical location that has consistently experienced a high prevalence of diarrhoea among CUF over the last decade nationally. This study examined whether agroecology influences Salmonella food contamination and exposure risk to CUF. A total of 240 food samples (PE: 78; APE: 73; AE: 89) were examined for Salmonella load using Xylose Lysine Deoxycholate Agar and confirmed using polymerase chain reaction targeting invA gene. Analysis of variance for nested design was used to compare Salmonella counts among food types within and across agroecologies and means were separated using Tukey Honestly Significant Difference test at 5% (p < 0.05). Proportion of foods with Salmonella load exceeding World Health Organisation (WHO) set-limit was expressed in percentage. Exposure risk of CUF was computed by multiplying quantity of food intake by Salmonella load and compared to minimum infectious dose (MID) of the pathogen (3 log CFU) whereas chi-square was used to compare proportions of CUF with exposure above or below MID among agroecologies. Salmonella load ranged from 0.00 ± 0.00 to 8.23 ± 1.12 log CFU but varied by food type and agroecology. Salmonella aggregated load in foods from PE was significantly higher than from APE or AE (p < 0.05). The proportion of Salmonella contaminated foods from PE, APE, and AE was 33–90%, 40–67%, and 17–88%, respectively. Salmonella exposure risks to CUF were similar (p > 0.05) at 96%, 92%, and 91% in PE, APE, and AE, respectively. Sorghum-based foods and leafy vegetables were the predominant high-risk foods. This study has revealed that Salmonella contamination of foods with high exposure risk among CUF in Karamoja sub-region varies with agroecology. Efforts to address food contamination in the sub-region should take into account agroecology.