Host Preferences and Impact of Climate on Blood Feeding in Anopheles funestus Group from South Africa

Abstract

Anopheles vaneedeni and Anopheles parensis (members of the An. funestus group) are generally not considered malaria vectors. However, both species were recently identified as potential vectors in South Africa. A critical factor needed to determine their role in malaria transmission is their preference for human blood. The human blood index of An. vaneedeni and An. parensis and their potential role in the ongoing residual malaria transmission in South Africa is unknown. This study aimed to identify host blood meals from the wild-caught An. funestus group in a longitudinal study, and to establish the relationship between temperature, relative humidity, and precipitation on host feeding preferences. Anopheles leesoni, An. parensis, An. vaneedeni, and Anopheles rivulorum were collected, and females mainly fed on cattle. Climatic parameters did not influence the host feeding preferences of these four members of the An. funestus group, but impacted the proportion of females that took a blood meal. Significant changes in feeding proportions were driven by relative humidity, temperature, and precipitation. The role of these species in the ongoing residual malaria transmission in South Africa needs further investigation, as no human blood meals were identified. It is recommended that vector surveillance teams incorporate climatic monitoring and host blood meal identification into their routine activities. This information could provide the malaria vector control programmes with scientific evidence to evaluate the importance of the An. funestus group in residual malaria transmission.