Community-led intensive trapping reduces abundance of key plague reservoir and flea vector.

Background: Zoonotic pathogens transmitted by rodents are highly prevalent in low-middle income countries and effective control measures that are easily implemented are urgently needed. Whilst rodent control seems sensible as a mitigation strategy, there is a risk that disease prevalence in reservoir populations can increase following control due to impacts on movement and demographics. Additionally, removing rodents from the population does not necessarily lead to reductions in abundance as populations can compensate for removal through increased breeding and immigration. In a previous study of intermittent control within houses, we showed that reduction in rodent abundance was only very short-term. Working in rural settings within the plague-endemic area of Madagascar, this study explores whether community-led daily intensive rodent trapping within houses can effectively reduce long-term rodent and flea abundance.

Main text: A rodent management experiment was carried out in six rural villages of Madagascar during 2022-2023. Three villages were selected as intervention villages, where intensive daily rodent trapping inside houses was conducted. Surveillance of rodent and flea abundance using traps and tiles took place at 4-month intervals. We show that community-led intensive rodent trapping in rural Malagasy households effectively reduced abundance of the main rodent reservoir (Rattus rattus) and indoor flea vector (Xenopsylla cheopis) of plague. Importantly, indoor abundance of the outside flea vector (Synopsyllus fonquerniei) did not increase.

Conclusions: Community-based intensive rodent trapping inside houses is an effective methodology in controlling key reservoirs and vectors of plague, which can be implemented by the communities themselves. Co-ordinated and sustained rodent control should be considered as an important plague mitigation strategy.