University of Massachusetts Medical School Faculty Publications

Title

Decreased Growth Rate of P. falciparum Blood Stage Parasitemia With Age in a Holoendemic Population

UMMS Affiliation

Department of Pediatrics; Department of Quantitative Health Sciences

Date

4-1-2014

Document Type

Article

Disciplines

Epidemiology | Immunology and Infectious Disease | Infectious Disease | Parasitic Diseases | Pediatrics

Abstract

In malaria holoendemic settings, decreased parasitemia and clinical disease is associated with age and cumulative exposure. The relative contribution of acquired immunity against various stages of the parasite life cycle is not well understood. In particular, it is not known whether changes in infection dynamics can be best explained by decreasing rates of infection, or by decreased growth rates of parasites in blood. Here, we analyze the dynamics of Plasmodium falciparum infection after treatment in a cohort of 197 healthy study participants of different ages. We use both polymerase chain reaction (PCR) and microscopy detection of parasitemia in order to understand parasite growth rates and infection rates over time. The more sensitive PCR assay detects parasites earlier than microscopy, and demonstrates a higher overall prevalence of infection than microscopy alone. The delay between PCR and microscopy detection is significantly longer in adults compared with children, consistent with slower parasite growth with age. We estimated the parasite multiplication rate from delay to PCR and microscopy detections of parasitemia. We find that both the delay between PCR and microscopy infection as well as the differing reinfection dynamics in different age groups are best explained by a slowing of parasite growth with age.

Comments

Citation: Pinkevych M, Petravic J, Chelimo K, Vulule J, Kazura JW, Moormann AM, Davenport MP. Decreased Growth Rate of P. falciparum Blood Stage Parasitemia With Age in a Holoendemic Population. J Infect Dis. 2014 Apr 1;209(7):1136-43. doi: 10.1093/infdis/jit613. Link to article on publisher's site

Related Resources

Link to Article in PubMed

Keywords

Malaria, Plasmodium falciparum, blood stage, immunity, mathematical modeling

PubMed ID

24265441