The role of vector population variation and climate in Zika virus transmission patterns in Africa: a modelling study.

Dr. Jamie Calwell

Jamie Calwell, Associate Research Scholar in Gabriel Vecchi’s group at The High Meadows Environmental Institute at Princeton has developed a modeling approach to assess Zika virus (ZIKV) transmission risk across Africa, finding that mosquito population genetics influence transmission more strongly than climate, and predicting that about three-quarters of the most populous African cities could become suitable for ZIKV transmission by the end of the century. 

ZIKV outbreaks have been rare in Africa despite favorable conditions.  Her work used modeling to see if this could be explained by misdiagnosis/underreporting or by overlooked aspects of the virus-vector-climate interplay that may impede transmission in Africa.  Specifically, she and her colleagues…

- Developed a mathematical model to assess Zika virus (ZIKV) transmission risk across Africa.

 - Parameterized the model using data from laboratory experiments on mosquito traits and ZIKV characteristics.

- Validated the model by comparing predicted transmission suitability with ZIKV seroprevalence surveys conducted across Africa.

- Used projections of mosquito genetics and climate to predict future ZIKV outbreak risk in 59 major African cities.

 - Derived an equation for the basic reproductive ratio (R0) that incorporates mosquito and virus traits that vary with mosquito ancestry and climate.

Mosquito genetic variation, specifically the proportion of urban habituated Aedes aegypti subspecies aegypti  ancestry, is more influential than climate in driving ZIKV transmission patterns in Africa, and that ongoing genetic surveillance of African mosquito populations is crucial for understanding and predicting ZIKV transmission risk across the continent.

Near-current and future Zika virus transmission suitability for the 59 most populous African cities

Caldwell JM, Lambrechts L, Rose NH. The role of vector population variation and climate in Zika virus transmission patterns in Africa: a modelling study. Lancet Planet Health. 2024 Dec;8(12):e1020-e1029. doi: 10.1016/S2542-5196(24)00276-6. PMID: 39674192.  https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(24)00276-6/fulltext