Anopheles mosquito exposure is associated with age, gender and bed net use in areas in Uganda experiencing varying malaria transmission intensity

  1. Sara Lynn Blanken
  2. Maxwell Kilama
  3. Jordache Ramjith
  4. Alex K. Musiime
  5. Kjerstin Lanke
  6. Daniel Ayo
  7. Kristiaan Huijbers
  8. Tom Hofste
  9. Melissa Conrad
  10. Paul Krezanoski
  11. Grant Dorsey
  12. Moses R. Kamya
  13. Emmanuel Arinaitwe
  14. Teun Bousema
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Abstract

Objectives

The number of Anopheles mosquito bites a person receives determines the risk of acquiring malaria and the likelihood of transmitting infections to mosquitoes. We assessed heterogeneity in Anopheles biting and associated factors in two settings in Uganda with different endemicity.

Methods

Plasmodium falciparum parasites in blood-fed indoor caught Anopheles mosquitoes were quantified using qPCR targeting the Pf18S rRNA gene. Human DNA in dried blood spots from household occupants and mosquito blood meals was profiled using 15 short-tandem repeats (STRs) and analysed using a log-likelihood approach for matching of both single and multi-sourced blood meals and incomplete DNA profiles.

Results

The distribution of mosquito bites was non-random; school-age children (5-15 years) and adults (≥16 years) had a mosquito biting rate ratio (BRR) 1.76 (95%CI 1.27-2.44, P < 0.001) and 1.96 (95%CI 1.41-2.73, P < 0.0001) times that of children under 5 years, respectively. Biting rates were lower in bed net users (BRR: 0.80, 95%CI 0.65-0.99, P = 0.042), and higher in males (BRR: 1.30, 95%CI 1.01-1.66, P = 0.043) and individuals infected with P. falciparum (BRR: 1.42, 95%CI 1.03-1.96, P = 0.030), though the latter effect lost statistical significance in sensitivity analyses.

Conclusions

Adults and school-age children are at higher risk for receiving mosquito bites and this has implications for the relative importance of demographic populations to onward malaria transmission to mosquitoes.

Highlights

  • A novel statistical approach allowed us to match multi-sourced mosquito bloodmeals and partially digested mosquito bloodmeals to human individuals

  • Participant age consistently related to mosquito biting: adults and school-age children had a mosquito biting rate ratio that was ∼2 and ∼1.8 times that of children below 5 years, respectively

  • Men received more mosquito bites than women and self-reported bed net use was associated with lower mosquito exposure.

  • Higher mosquito biting rates were observed in individuals infected with Plasmodium falciparum

Article activity feed

  1. Version published to 10.1101/2024.12.12.24318757v1 on medRxiv