What Is The Expected Impact On Malaria Transmission Dynamics In A Region With High Seasonal Rainfall Variability If The Anopheles Gambiae Mosquito Population Shifts From Being Predominantly Zoophilic To Anthropophilic, Assuming A Moderate Level Of Insecticide-treated Bed Net Coverage And A Recent Introduction Of The Pfhrp2/3 Deletion In The Local Plasmodium Falciparum Parasite Population?

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The shift of Anopheles gambiae from zoophilic to anthropophilic behavior in a region with high seasonal rainfall variability, coupled with moderate insecticide-treated bed net coverage and the Pfhrp2/3 deletion in Plasmodium falciparum, is expected to significantly impact malaria transmission dynamics as follows:

  1. Increased Transmission Potential:

    • The shift to anthropophilic feeding behavior increases the frequency of human-mosquito contact, enhancing the potential for malaria transmission. This change makes mosquitoes more efficient vectors, even with fluctuations in population due to rainfall variability.

  2. Impact of Bed Nets:

    • While insecticide-treated bed nets reduce bites, moderate coverage may not fully mitigate the increased transmission from more anthropophilic mosquitoes. Consistency in use and potential insecticide resistance (not mentioned but a consideration) could affect their efficacy.

  3. Pfhrp2/3 Deletion Effects:

    • This deletion impairs rapid diagnostic tests, leading to underdiagnosis and potential untreated cases. Asymptomatic carriers may act as reservoirs, sustaining transmission and complicating control efforts.

  4. Seasonal Rainfall Influence:

    • High variability may cause population spikes during wet seasons, increasing transmission. Dry seasons might reduce populations, but the anthropophilic shift could maintain transmission efficiency even with fewer mosquitoes.

  5. Indirect Consequences:

    • The Pfhrp2/3 deletion hinders case tracking and treatment, indirectly supporting ongoing transmission. This, combined with more efficient vectors, could lead to sustained or increased transmission intensity.

In conclusion, the region is likely to experience an increase in malaria transmission intensity, driven by more efficient vectors and challenges in diagnosis, despite some mitigating effects from bed nets and seasonal population fluctuations.