P-72 First report of Mansonia indubitans in Guyana

Methods: Adult mosquito specimens were collected using an aspirator from the village of Arakaka in Region One in May 2025 during routine mosquito surveillance. Specimens were pinned, photographed and morphologically identified using an AmScope Dissecting Circuit 144-LED Zoom Stereo Microscope with digital camera and taxonomic keys.

Results: This is the first report of Mansonia indubitans in Guyana. Both samples were captured in Region One, Barima Waini. One specimen was collected at the Arakaka Primary School on May 28th 2025 and the other on May 29th 2025 at the Police Outpost. This species complements the other three Mansonia identified in Guyana; Mansonia humeralis, Mansonia pseudotitillans and Mansonia titillans. Specimens were morphologically distinguished from other Mansonia based on the length of the maxillary palpus and the absence of spiniform setae on the apex of abdominal tergites VII and VIII.

Conclusion: The detection of Mansonia indubitans in Guyana fills a critical knowledge gap regarding its distribution across South America and carries important public health implications. As a potential vector of arboviruses such as Mayaro, chikungunya, Zika, and Venezuelan Equine Encephalitis, its presence adds to the existing risk landscape in a country already experiencing dengue outbreaks. Additionally, given Guyana’s ongoing efforts toward the elimination of lymphatic filariasis as a public health problem, the identification of a species associated with filarial transmission elsewhere is particularly significant. This finding contributes valuable data for triangulation within national surveillance systems and highlights the need to expand entomological monitoring to include Mansonia species. Mapping its distribution will support more targeted, evidence-based vector control interventions and strengthen Guyana’s preparedness and progress toward vector-borne disease control and elimination goals.