The age distribution of a mosquito population has a considerable effect on its ability to vector disease. Specifically, older mosquitoes have bitten a greater number of people in their lifetime, and thus are more likely to have bitten an infected human, survived through the pathogen’s incubation, and become infectious.
Despite that, there are currently few methods for determining the age of mosquitoes, and other suffer from considerable imprecision. As new techniques for age grading mosquitoes emerge, a natural question that arises is how precise do these techniques need to be to be useful? We answer this question by first acknowledging that imprecision in age grading translates into imprecision in estimates of disease incidence based on age grading. Mosquito age structure is regularly altered by interventions, making this question particularly relevant to those interested in using changes in mosquito age distribution as proxies of changes in disease incidence.
Results/Conclusions
Through utilization of mathematical models of disease incidence in humans, we found that the precision of mosquito age grading must be more accurate in populations with shorter average lifespans to accurately predict human disease incidence. This assessment was based on simulation results showing wider confidence bands for estimates of disease incidence with increasing mean lifespan.
We also simulated a scenario in which one population of mosquitoes was subject to a lifespan-reducing intervention and another group acted as a control. We found that a larger sample of mosquitoes would be needed for the analysis to have acceptable power in populations where mean lifespan is shorter. These results have implications for testing how a wide range of interventions targeting mosquitoes will affect disease incidence in humans.