Ecological and environmental conditions correlate with flea population within human habitations in a plague focus, Mbulu district, Tanzania.

Abstract

Plague persistence remains a major health concern in some African countries. Although the role of some flea vectors in their transmission is widely known, the local-scale factors contributing to human plague recurrence are still poorly understood, thwarting the potential disease mitigation measures in affected communities. We examined the flea population and their relationship to household practices in rural Mbulu District, northern Tanzania. We sampled fleas from both host (170 rodents in 3 species) and household interiors using a Light trap (Ltrap). We found seven species of flea inhabiting the human dwelling, with Xenopsylla brasilliensis the most common species occupying rodent species and the in-house environment. Dinopsylla lypusus and three others: Ctenocephalides canis, Ctenocephalides felis and Xenopsylla cheopis, partitioned between the rodents and the house environment, respectively, indicating niche separation and distinct disease transmission risks in these vectors. Further, the flea index varied throughout the sampling period, with the total flea index exceeding the threshold of 1. We observed that X. brasilliensis (mean = 1.93 ± 0.56SE, p < 0.001) significantly increased the abundance of rodent fleas. Furthermore, households without keeping livestock under the same roof (mean = - 0.97 ± 0.16SE, p < 0.001) and not owning livestock (mean = -1. 45 ± 0.31SE, p < 0.001) had a higher likelihood of decreased house flea population than households sharing livestock under one roof. Similarly, houses with bed arrangements with a sleeping loft positively correlated with increased rodent flea abundance (mean = 1.88 ± 1.04SE, p = 0.07), strongly suggesting the importance of improving rural lifestyle. Enhancing public education on hygiene and flea control measures to reduce the risks of plague persistence and transmission in these rural communities is an increasing priority.