Figure 8 fitness login
However, many of these and other efforts to examine the relationship between Anopheles and Plasmodium have for experimental simplicity often resorted to employing unnaturally high mosquito infection intensities that might have artifactually altered the natural relationships between Anopheles and Plasmodium 11, 12, 13, 14. Indeed, several studies support a hypothesis that pathogenic malaria in humans and Plasmodium infection of vectors may modulate mosquito behavior and physiology to increase the likelihood of pathogen transmission 8, 9, 10, 11. As such, Anopheles blood-meal host-seeking and preference are critical behaviors for regulating the synergistic processes that ultimately impact the mosquito’s vectorial capacity. Blood feeding, which is carried out solely by adult females, is a central factor that positively affects the complex Anopheles-Plasmodium paradigm. Despite the complexity of the interlaced Anopheles-Plasmodium life cycles and the inherent ecological and environmental challenges, it is often surprising that in malaria-endemic regions of Sub-Saharan Africa, where there is a high disease prevalence, the percentage of infectious mosquitoes within surveys of Anopheles populations is actually very low, typically ranging from 1 to 10% 7. gambiae adult females are only infectious to humans when the Plasmodia they harbor complete a multi-stage sporogonic cycle and successfully invade the mosquito’s salivary glands. Anopheles mosquitoes are anautogenous females require a blood meal for reproduction and replenishment of energy stores 6. Plasmodium parasites are solely vectored between humans by mosquitoes within the genus Anopheles 4, 5. Of utmost importance is Plasmodium falciparum, which causes severe health complications and the highest human mortality rate 3. Human malaria is the result of pathogenic infection by five species of unicellular Plasmodium (Haemosporidia: Plasmodiidae) 2.
Globally, malaria remains the most endemic infectious mosquito-borne disease, with over 500 million cases per annum, and putative vectors present in almost 100 countries worldwide placing up to 40% of the world’s population at risk 1.
Taken together, these data argue against the long-held paradigm that malaria infection is pathogenic for anophelines and, instead suggests there are biological and evolutionary advantages for the mosquito that drive the preservation of its high vectorial capacity. When compared with their uninfected counterparts, Plasmodium infected mosquitoes exhibit increased transcript abundance of genes associated with olfactory acuity as well as a range of synergistic processes that align with increased fitness based on both anti-aging and reproductive advantages.
head, sensory appendages, and salivary glands. To begin to answer this, we have completed a comparative RNAseq-based transcriptome profile study examining the effect of biologically salient, salivary gland transmission-stage Plasmodium infection on the molecular physiology of Anopheles gambiae s.s. An open question in the biology of malaria transmission is the impact of naturally occurring low-level Plasmodium infections of the vector on the mosquito’s health and longevity as well as critical behaviors such as host-preference/seeking. The continuing global impact of malaria reflects the evolutionary success of a complex vector-pathogen relationship that accordingly has been the long-term focus of both debate and study. Anopheline mosquitoes are the sole vectors for the Plasmodium pathogens responsible for malaria, which is among the oldest and most devastating of human diseases.