Could tungiasis jump to Asia? Modelling habitat suitability and establishment risk for the tungiasis flea (Tunga penetrans) in South Asia and Southeast Asia.

Tungiasis is a neglected tropical disease (NTD) caused by the jigger flea (Tunga penetrans) which typically invades the sole of the foot causing serious morbidity and sometimes mortality through secondary infections such as tetanus. Although tungiasis is found throughout tropical regions of the Americas and Africa, it has not yet become established in tropical Asia. Due to the large human population and extensive poverty in tropical Asia, an introduction of T. penetrans would pose a serious public health threat. Therefore, to estimate the extent of suitable habitat in tropical Asia and to identify areas at high risk of tungiasis outbreaks, niche modelling using climate, soil, and poverty data was performed. This allowed identification of zones where high poverty overlap with high environmental suitability for T. penetrans. Models projected that the most environmentally suitable regions in South Asia included the west coast of India, costal Sri Lanka, the Meghna delta and catchment, Andaman Islands, and coastal Myanmar. The areas predicted to have the highest risk of tungiasis emergence were the Meghna delta and catchment and the Ayeyarwady region (Myanmar). In Southeast Asia, the areas with the highest environmental suitability included Indochina, central and northern Philippines, the eastern coast of Peninsula Malaysia, the Lesser Sunda islands and the lowlands of West Papua. The areas predicted to have the highest risk of tungiasis outbreaks were Laos, Cambodia, Vietnam, the central Philippines, and the Lesser Sunda islands. With increased trade and travel between tropical Asia and tungiasis-endemic regions, public health safeguards such as enhanced monitoring in high-risk areas and travel health education are needed to prevent the spread of tungiasis to Asia.