Human-bat Competition on Cultivated Fruit Resources Promotes Bat-borne Pathogens Spillover to Humans and Domestic Animals in Bangladesh: An Exploratory Qualitative Study.

BACKGROUND

Nipah virus (NiV) outbreaks have recurred nearly annually in Bangladesh since 2001, with a fatality >70%. These outbreaks are primarily linked to the consumption of raw date palm sap (RDPS), which is contaminated by Indian flying fox bats. Due to the rapidly changing ecology, bats increasingly depend on cultivated fruits. To address this, we observed how humans and domestic animals compete and interact with bats for cultivated fruits facilitate pathogen transmission to humans and animals.

METHODS

We conducted an exploratory qualitative study in 4 NiV outbreak districts of Bangladesh spanning both the summer (April-June) and winter (December-February) of 2021 and 2022, including 60 ethnographic interviews and 24 observations with fruit orchard owners and RDPS harvesters.

RESULTS

Almost all participants reported frequent visits of fruit bats to cultivated fruit orchards and RDPS trees. They noted wild fruit trees are scarce in their localities due to deforestation, resulting in bats turning to feed on cultivated fruits and RDPS. Participants also reported consuming bat-bitten dropped fruits and RDPS, occasionally feeding them to domestic animals, which also consume these fruits while grazing in the orchards. Orchard owners often use nets to protect their fruits from bats, and are exposed to bats during removal from the nets. Even some local ethnic people collect the trapped bats for consumption. Although RDPS harvesters use protective measures, bats scratch them to access and consume sap.

CONCLUSIONS

The study's findings highlight the significance of increasing human-bat and domestic animal-bat food competition on cultivated fruits. We recommend future studies on ecological and behavioral interventions to prevent bat-borne pathogen spillover to humans and animals.