Mosquito-borne viruses are becoming a serious public health problem worldwide as they spill out from their wild sylvatic habitat to emerge in many urban areas in all continents wherever competent vectors are present. Mosquito vector competence assays are needed to assess emerging virus compabilities with local mosquito species and populations, and thus, the risk of emergence.
Mosquito vector competence for viruses was reported to differ according to the virus dose, mosquito populations, virus isolates, or their combinations. More complex interactions between intrinsic (eg. mosquito virome, endogenous non-retroviral elements or bacterial microbiome) or environmental (eg. temperature, rearing or experimental settings) conditions might further complicate comparisons across vector competence studies.
Vector competence, and more specifically systemic infection and transmission rates, is a dynamic process scaled in a day unit. Starting at 0% at the day of infection, the probability for an infected mosquito to transmit a virus increases over time until to reach a maximum at time t. The cumulative distribution of virus transmission’s probabilities is shaped by the distribution of extrinsic incubation period (EIP) values (EIP refers to the time needed for an infected mosquito to become infectious).
This project aims to obtain a more comprehensive view of mosquito-borne viruses transmission dynamics in the field by integrating intra-hosts virus parameters. In addition, we believe that the modelisation of the probability to transmit a virus over time for a given reference set of conditions can facilitate inter-studies comparisons.
Preliminary results can be accessed at :https://www.biorxiv.org/content/10.1101/764498v1. Here, we revealed high infection rates and unpreceded levels of systemic infection rates in both Metropolitan France and the Reunion island Ae. albopictus populations experimentally exposed to ZIKV, without differences in infection rates or intra-mosquito systemic infection dynamics between the two mosquito populations. Ten and 20-days were needed by the virus to disseminate in 50% and 100% of the exposed mosquitoes respectively. Our results highlight that Ae. albopictus populations present in Metropolitan France and the French territoires in the Indian Ocean might become potential vector for autochthonous ZIKV transmissions.