Heterogeneous malaria transmission in long-term Afghan refugee populations: a cross-sectional study in five refugee camps in northern Pakistan.
BACKGROUND
Afghan refugees in northern Pakistan have been resident for over 30 years and current information on malaria in this population is sparse. Understanding malaria risk and distribution in refugee camps is important for effective management both in camps and on return to Afghanistan.


METHODS
Cross-sectional malariometric surveys were conducted in five Afghan refugee camps to determine infection and exposure to both Plasmodium falciparum and Plasmodium vivax. Factors associated with malaria infection and exposure were analysed using logistic regression, and spatial heterogeneity within camps was investigated with SatScan.


RESULTS
In this low-transmission setting, prevalence of infection in the five camps ranged from 0-0.2 to 0.4-9 % by rapid diagnostic test and 0-1.39 and 5-15 % by polymerase chain reaction for P. falciparum and P. vivax, respectively. Prevalence of anti-malarial antibodies to P. falciparum antigens was 3-11 and 17-45 % for P. vivax antigens. Significant foci of P. vivax infection and exposure were detected in three of the five camps. Hotspots of P. falciparum were also detected in three camps, only one of which also showed evidence of P. vivax hotspots.


CONCLUSIONS
There is low and spatially heterogeneous malaria transmission in the refugee camps in northern Pakistan. Understanding malaria risk in refugee camps is important so the malaria risk faced by these populations in the camps and upon their return to Afghanistan can be effectively managed.
Department of Zoology, University of Peshawar, Peshawar, Pakistan.
Sobia
S
Wahid
Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, Keppel Street, London, WCIE 7HT, UK.
Gillian H
GH
Stresman
Vector Control Department, Merlin Malaria Control Programme, Khyber Pakhtunkhwa, Pakistan.
Syed Sajid
SS
Kamal
Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, Keppel Street, London, WCIE 7HT, UK.
Nuno
N
Sepulveda
Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, WCIE 7HT, UK.
Immo
I
Kleinschmidt
Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, Keppel Street, London, WCIE 7HT, UK.|Department of Medical Microbiology, Radboud University Medical Center, 6500, Nijmegen, The Netherlands.
Teun
T
Bousema
Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, Keppel Street, London, WCIE 7HT, UK. Chris.Drakeley@lshtm.ac.uk.
Chris
C
Drakeley
D000293:Adolescent; D000328:Adult; D000346:Afghanistan / Q000208:ethnology; D000368:Aged; D000953:Antigens, Protozoan / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D016015:Logistic Models; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000469:parasitology / Q000635:transmission*; D016780:Malaria, Vivax / Q000453:epidemiology / Q000469:parasitology / Q000635:transmission*; D008297:Male; D008875:Middle Aged; D010154:Pakistan / Q000453:epidemiology; D010963:Plasmodium falciparum / Q000502:physiology; D010966:Plasmodium vivax / Q000502:physiology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012036:Refugees; D018570:Risk Assessment; D055815:Young Adult
D000953:Antigens, Protozoan
Afghan refugees; Hotspots of exposure; Malaria transmission; Pakistan; Plasmodium falciparum; Plasmodium vivax