Anopheles mortality is both age- and Plasmodium-density dependent: implications for malaria transmission

Area of Science:

• Vector biology
• Malaria transmission dynamics
• Parasitology

Background:

• Vector daily mortality is crucial for pathogen transmission, yet models often assume it's independent of age and infection.
• Previous research on Plasmodium-induced mosquito mortality shows conflicting results, with limited focus on infection density's impact.

Purpose of the Study:

• To investigate the relationship between Plasmodium infection intensity and Anopheles stephensi mosquito survival.
• To determine how parasite density affects mosquito mortality rates and life expectancy.

Main Methods:

• Conducted three experiments using Anopheles stephensi mosquitoes exposed to varying Plasmodium berghei ookinete densities.
• Monitored daily mortality and dissected live mosquitoes to quantify parasite density in midgut and salivary glands.

Main Results:

• Mosquito mortality is dependent on both age and Plasmodium infection intensity.
• Higher parasite loads correlated with increased mosquito mortality, particularly with advancing age.
• Mosquito life expectancy is significantly influenced by Plasmodium infection density.

Conclusions:

• Parasite density directly impacts mosquito survival, contributing to a more detailed understanding of sporogony.
• Findings highlight the importance of infection intensity in malaria transmission models.
• Results have implications for developing and evaluating malaria transmission-blocking interventions.