A regional One Health approach to the risk of invasion by Anopheles stephensi in Mauritius

Abstract

BackgroundAnopheles stephensi is an invasive malaria vector in Africa that threatens to put an additional 126 million people at risk of malaria if it continues to spread. The island nation of Mauritius is highly connected to Asia and Africa and is at risk of introduction due to this connectivity. For early detection of An. stephensi, the Vector Biology and Control Division under the Ministry of Health in Mauritius, leveraged a well-established Aedes program, as An. stephensi is known to share Aedes habitats. These efforts triggered multisectoral coordination and cascading benefits of integrated vector and One Health approaches. MethodsBeginning June 2021, entomological surveys were conducted at points of entry (seaport, airport) and on ships transporting livestock in collaboration with the Civil Aviation Department, the Mauritian Port Authority and National Veterinary Services. A total of 39, 18, 723 mosquito larval surveys were respectively conducted in the seaport, airport and other localities in Mauritius while 20, two and 26 adult mosquito surveys were respectively conducted in the seaport, airport and twenty-six animal points. Alongside adult mosquito surveys, surveillance of vectors of veterinary importance (e.g.- licoides spp.) was also carried out in collaboration with National Parks and Conservation Service and land owners. ResultsA total of 8,428 adult mosquitoes were collected and 1,844 larval habitats were positive for mosquitoes. All collected mosquitoes were morphologically identified and 151 Anopheles and 339 Aedes mosquitoes were also molecularly characterized. Mosquito species detected were Aedes albopictus, Anopheles arabiensis, An. coustani, An. merus, Culex quinquefasciatus, Cx. thalassius and Lutzia tigripes. Anopheles stephensi was not detected. The One Health approach was shared with the French Agricultural Research Centre for International Development (CIRAD), strengthening collaboration between Mauritius and Reunion Island on vector surveillance at entry points and insecticide resistance monitoring. The Indian Ocean Commission (IOC) was also alerted to the risk of An. stephensi, leading to regional efforts supporting trainings and development of a response strategy to An. stephensi bringing together stakeholders from Comoros, Madagascar, Mauritius, Reunion Island and Seychelles. ConclusionsMauritius is a model system showing how existing public health entomology capabilities can be used to enhance vector surveillance and control and create multisectoral networks to respond to any emerging public and veterinary health vector-borne disease threat. Author summaryThe malaria mosquito, Anopheles stephensi, is invasive in Africa where it threatens to put an additional 126 million people at risk of malaria if it continues to spread throughout the continent. The island nation of Mauritius is highly connected to Asia and Africa through maritime trade and therefore may be at risk of An. stephensi introduction and establishment. Mauritius implemented a One Health approach, enhancing entomological surveillance at entry points and collaborating across sectors (e.g. veterinary services, sea and air port authorities, national parks and conservation, communities, etc.) conducted extensive integrated vector surveillance, inspecting 85,071 larval habitats, and analyzing 8,428 adult mosquitoes morphologically and molecularly. Although An. stephensi was not detected, the initiative catalyzed and strengthened multisectoral partnerships nationally and across the Indian Ocean region member states (Comoros, Madagascar, Mauritius, Reunion Island and Seychelles). Leveraging the threat of An. stephensi, Mauritius exemplifies utilizing existing capabilities to create multisectoral networks for effective vector surveillance and response.