Association between Subclinical Malaria Infection and Inflammatory Host Response in a Pre-Elimination Setting.
PLoS One
; 11(7): e0158656, 2016.
Article
in En
| MEDLINE
| ID: mdl-27386859
ABSTRACT
BACKGROUND:
Subclinical infections in endemic areas of Southeast Asia sustain malaria transmission. These asymptomatic infections might sustain immunity against clinical malaria and have been considered benign for the host, but if they are associated with chronic low-grade inflammation this could be harmful. We conducted a case-control study to explore the association between subclinical malaria and C-reactive protein (CRP), an established biomarker of inflammation.METHODS:
Blood samples from asymptomatic villagers in Pailin, Western Cambodia were tested for malaria by high-volume ultra-sensitive polymerase chain reaction (uPCR) to determine the Plasmodium species. Plasma CRP concentration was measured in 328 individuals with parasitaemia (cases) and compared with i) the same individual's value at the first time point when they had no detectable parasites (n = 282); and ii) age- sex- and village-matched controls (n = 328) free of Plasmodium infection. Plasma CRP concentrations were compared against thresholds of 3mg/L and 10mg/L. Subgroup analysis was carried out for cases with P vivax and P falciparum mono-infections.RESULTS:
Median plasma CRP level for all samples was 0.59mg/L (interquartile range 0.24-1.64mg/L). CRP concentrations were higher in parasitaemic individuals compared with same-person-controls (p = 0.050); and matched-controls (p = 0.025). 4.9% of samples had CRP concentrations above 10mg/L and 14.6% were above 3mg/L. Cases were more likely to have plasma CRP concentrations above these thresholds than age/sex matched controls, odds ratio 3.5 (95%CI 1.5-9.8) and 1.8 (95%CI 1.1-2.9), respectively. Amongst cases, parasite density and CRP were positively correlated (p<0.001), an association that remained significant when controlling for age and fever. Individuals with P.vivax mono-infections had the highest plasma CRP concentrations with the greatest association with parasitaemia.DISCUSSION:
In this setting persistent malaria infections in asymptomatic individuals were associated with moderately elevated plasma CRP concentrations; chiefly evident in cases with P.vivax mono-infections. As well as interrupting malaria transmission within the community, treatment of asymptomatic malaria infections, in particular radical cure of vivax malaria, may benefit the health of infected individuals.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Malaria, Vivax
/
Malaria, Falciparum
/
Asymptomatic Infections
/
Inflammation
Type of study:
Observational_studies
/
Risk_factors_studies
Limits:
Adolescent
/
Adult
/
Child
/
Child, preschool
/
Female
/
Humans
/
Infant
/
Male
Country/Region as subject:
Asia
Language:
En
Journal:
PLoS One
Journal subject:
CIENCIA
/
MEDICINA
Year:
2016
Document type:
Article
Affiliation country:
Thailand