[Arbovirus transmission cycles in Madagascar]

Area of Science:

• * Arbovirology and Vector-borne Diseases
• * Epidemiology and Public Health
• * Entomology and Virology

Context:

• * Madagascar's unique biogeographic characteristics, including isolation and high endemicity, influence arbovirus dynamics.
• * Previous arbovirus surveillance data from 1965-1982 provide historical context for current findings.
• * Understanding arbovirus circulation is crucial for public health in Madagascar and surrounding regions.

Purpose:

• * To determine arbovirus epidemiological patterns in Madagascar through comprehensive entomological, serological, and virological surveys.
• * To identify potential arbovirus vectors and assess the risk of introduction and amplification of key arboviruses.
• * To investigate the transmission cycles of specific arboviruses circulating on the island.

Summary:

• * Extensive entomological surveys identified over 107 arthropod species, including three new species, and 4183 inoculation pools.
• * Serological studies on humans and animals revealed widespread arbovirus circulation, with a predominance of Flavivirus, including West Nile virus.
• * Nine arboviruses were isolated, including Dengue-2 virus, and transmission cycles of eight viruses (Babanki, West Nile, Rift Valley Fever, Crimean-Congo Hemorrhagic Fever, MMP 158, Ngari, Perinet, Andasibe) were studied.

Impact:

• * Identifies a very high risk for dengue introduction and amplification due to susceptible mosquito vectors and regional viral activity.
• * Assesses intermediate risk for other arboviruses like Japanese encephalitis and Chikungunya, and low risk for Yellow Fever.
• * Provides critical data for public health preparedness and targeted vector control strategies in Madagascar.