A single bite from an infected mosquito can be enough to transmit the Rift Valley fever virus and make a sheep sick. This is one of the conclusions of Wageningen University & Research’s research into a model to quantify the efficiency of virus transmission. The scientists published their research in Frontiers in Cellular and Infection Microbiology.
Rift Valley fever virus is a mosquito-borne pathogen. How the virus spreads through a population depends on interactions between the vector, host, and pathogen. Researchers at Wageningen University & Research designed a study design to evaluate whether and how infections develop in animals exposed to the virus.
In this experimental design, the focus was on Aedes a Egypti mosquitoes for transmission of Rift Valley fever virus to lambs. The animals were exposed to different numbers of infected mosquitoes. Exposure to 1–3 mosquitoes was considered “low exposure”; Seven to nine mosquitoes were considered “high exposure.” All lambs in the final group became infected within 2-4 days and showed characteristic signs of the disease. In the “low exposure” group, 3 out of 12 animals developed viremia and disease.
The results of the experiment were used to estimate the transfer efficiency. The transmission efficiency per bite from mosquito to host has been estimated at 28%. Using the Ross-McDonald mathematical model, transmission efficiency was combined with estimates of the life characteristics of Aedes a Egypti or related mosquitoes.
The model was then used to illustrate scenarios that could lead to large outbreaks in a population that had never previously experienced outbreaks of Rift Valley fever virus. According to the model, two factors are important for the rapid spread of the disease: Both a relatively large number of mosquitoes per animal and mosquitoes that can transmit the virus when feeding on animals are needed for the disease to spread.
Further information is available in the publication “Quantification of Rift Valley fever virus transmission efficiency in a lamb-mosquito-lamb model” in Frontiers in Cellular and Infection Microbiology.
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2024-01-02 11:29:55
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