Back to Search
Start Over
Clustered local transmission and asymptomatic Plasmodium falciparum and Plasmodium vivax malaria infections in a recently emerged, hypoendemic Peruvian Amazon community
Clustered local transmission and asymptomatic Plasmodium falciparum and Plasmodium vivax malaria infections in a recently emerged, hypoendemic Peruvian Amazon community
- Source :
- Malaria Journal, Malaria Journal, Vol 4, Iss 1, p 27 (2005)
- Publication Year :
- 2005
-
Abstract
- Background There is a low incidence of malaria in Iquitos, Peru, suburbs detected by passive case-detection. This low incidence might be attributable to infections clustered in some households/regions and/or undetected asymptomatic infections. Methods Passive case-detection (PCD) during the malaria season (February-July) and an active case-detection (ACD) community-wide survey (March) surveyed 1,907 persons. Each month, April-July, 100-metre at-risk zones were defined by location of Plasmodium falciparum infections in the previous month. Longitudinal ACD and PCD (ACP+PCD) occurred within at-risk zones, where 137 houses (573 persons) were randomly selected as sentinels, each with one month of weekly active sampling. Entomological captures were conducted in the sentinel houses. Results The PCD incidence was 0.03 P. falciparum and 0.22 Plasmodium vivax infections/person/malaria-season. However, the ACD+PCD prevalence was 0.13 and 0.39, respectively. One explanation for this 4.33 and 1.77-fold increase, respectively, was infection clustering within at-risk zones and contiguous households. Clustering makes PCD, generalized to the entire population, artificially low. Another attributable-factor was that only 41% and 24% of the P. falciparum and P. vivax infections were associated with fever and 80% of the asymptomatic infections had low-density or absent parasitaemias the following week. After accounting for asymptomatic infections, a 2.6-fold increase in ACD+PCD versus PCD was attributable to clustered transmission in at-risk zones. Conclusion Even in low transmission, there are frequent highly-clustered asymptomatic infections, making PCD an inadequate measure of incidence. These findings support a strategy of concentrating ACD and insecticide campaigns in houses adjacent to houses were malaria was detected one month prior.
- Subjects :
- Adult
Male
medicine.medical_specialty
lcsh:Arctic medicine. Tropical medicine
Time Factors
Adolescent
lcsh:RC955-962
Plasmodium vivax
Plasmodium falciparum
Asymptomatic
lcsh:Infectious and parasitic diseases
Antimalarials
parasitic diseases
Anopheles
Peru
medicine
Malaria, Vivax
Prevalence
Animals
Humans
lcsh:RC109-216
Malaria, Falciparum
Child
Aged
Aged, 80 and over
biology
Transmission (medicine)
Incidence (epidemiology)
Incidence
Research
Infant
Middle Aged
biology.organism_classification
medicine.disease
Virology
Suburban Population
Infectious Diseases
Child, Preschool
Tropical medicine
Parasitology
Female
medicine.symptom
Malaria
Subjects
Details
- ISSN :
- 14752875
- Volume :
- 4
- Database :
- OpenAIRE
- Journal :
- Malaria journal
- Accession number :
- edsair.doi.dedup.....79ba0c9a2c85e6813038ad355d0525f1