Impact of habitat modifications on flea (Siphonaptera) infestation dynamics of non-volant small mammals across wildlife-human interfaces in Tanzania

Abstract

Changes in natural habitats affect the population density of small mammals, which in turn influences ectoparasite populations. This study explores how human-induced habitat modifications impact flea infestations of non-volant small mammals considering seasonal and agroecological variations. A cross-sectional study focused on two wildlife-human interfaces in the Iringa and Morogoro regions, Tanzania. Small mammals were captured using Sherman®, Havahart, and wire-cage live traps. Fleas were extracted from the animals' fur with a stiff brush and preserved in 70% alcohol. Flea identification was performed morphologically by using standard guidelines and confirmed by sequencing the mtDNA segment of the <i>cox2</i> gene. Statistical analyses were performed using Zero-Inflated Negative Binomial (ZINB) and Generalized Linear Models (GLMs) to examine variations in flea infestations across different host species, habitat types, seasons, and agroecological zones. Species diversity of small mammals decreased with increasing habitat modification (bush > farm > peridomestic). The most common rat fleas (<i>Xenopsylla cheopis</i>, <i>Xenopsylla brasiliensis)</i>, together with chicken flea (<i>Echidnophaga gallinacea</i>) and cat flea (<i>Ctenocephalides felis</i>), were identified. Flea infestation loads on small mammals increased along the habitat modification gradient (bush < farm < peridomestic). The highest prevalence and mean intensity of infestation were observed in <i>Aethomys</i> spp. at 38.5% (95% CI: 33.7- 43.7) and 2.95 (95% CI: 2.18 - 3.72, SE: 0.366), respectively. Despite <i>Mastomys natalensis</i> being the most abundant, they had a lower prevalence of flea infestation. Flea infestations were significantly higher during the rainy season than the dry season (<i>p</i>-value = 0.003) and more prevalent in peridomestic habitats than others (<i>p</i>-value = 0.014). Thus, habitat modification directly impacts flea infestation loads and small mammal species' diversity, potentially implicating zoonotic disease transmission. This highlights the urgent need for integrated wildlife conservation and public health management approaches in Tanzania.