Asymptomatic falciparum and Non-falciparum Malarial Parasitemia in Adult Volunteers with and without HIV-1 Coinfection in a Cohort Study in Western Kenya

Am J Trop Med Hyg. 2021 Jun 7;105(1):159-166. doi: 10.4269/ajtmh.21-0012.


Asymptomatic malarial parasitemia represents the largest reservoir of infection and transmission, and the impact of coinfection with HIV-1 on this reservoir remains incompletely described. Accordingly, we sought to determine the prevalence of asymptomatic malarial parasitemia in Kombewa, Western Kenya, a region that is endemic for both malaria and HIV-1. A total of 1,762 dried blood spots were collected from asymptomatic adults in a cross-sectional study. The presence of parasitemia was first determined by a sensitive Plasmodium genus-specific 18S assay, followed by less sensitive species-specific DNA-based quantitative polymerase chain reaction (PCR) assays. The prevalence of asymptomatic malarial parasitemia by 18S genus-specific PCR assay was 64.4% (1,134/1,762). Of the 1,134 malaria positive samples, Plasmodium falciparum was the most prevalent species (57.4%), followed by Plasmodium malariae (3.8%) and Plasmodium ovale (2.6%) as single or mixed infections. As expected, the majority of infections were below the detection limit of microscopy and rapid diagnostic tests. HIV-1 prevalence was 10.6%, and we observed a significant association with malarial parasitemia by χ2 analysis (P = 0.0475). Seventy-one percent of HIV-1 infected volunteers were positive for Plasmodium 18S (132/186), with only 29% negative (54/186). In HIV-1-negative volunteers, the proportion was lower; 64% were found to be positive for 18S (998/1,569) and 36% were negative (571/1,569). Overall, the prevalence of asymptomatic malarial parasitemia in Western Kenya is high, and knowledge of these associations with HIV-1 infection are critically important for malaria elimination and eradication efforts focused on this important reservoir population.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Asymptomatic Infections / epidemiology
  • Cohort Studies
  • Coinfection / pathology*
  • Cross-Sectional Studies
  • Female
  • HIV-1 / pathogenicity*
  • Healthy Volunteers
  • Humans
  • Kenya / epidemiology
  • Malaria / blood
  • Malaria / epidemiology
  • Malaria / pathology*
  • Malaria, Falciparum / blood
  • Malaria, Falciparum / epidemiology
  • Malaria, Falciparum / pathology*
  • Male
  • Middle Aged
  • Parasitemia / blood
  • Plasmodium falciparum / genetics*
  • Prevalence
  • Young Adult