Molecular epidemiology and seroprevalence in asymptomatic Plasmodium falciparum infections of Malagasy pregnant women in the highlands.
BACKGROUND
Malaria epidemiology in Madagascar is classified into four different areas, ranging from unstable seasonal transmission in the highlands to hyperendemic perennial transmission areas in the costal level. Most malaria studies in Madagascar are focused on symptomatic children. However, because of the low transmission in some areas with correspondingly low level of semi-immunity, adults are also at risk, in particular pregnant women. The objective of this study was to gain information on the genetic epidemiology of malarial infections in pregnant women in order to provide information for malaria control and elimination programmes in Madagascar.


METHODS
Between May and August 2010, we carried out cross-sectional surveys targeting healthy pregnant women in six locations, three in the coastal area and three in the highlands at 850-1300 m. 1244 blood samples were screened for anti-Plasmodium falciparum antibodies by immunofluorescence test and for malarial infection by realtime-PCR. The prevalence of chloroquine and sulphadoxine-pyrimethamine resistance markers was also determined in all Plasmodium falciparum samples by PCR-RFLP as well as the multiplicity of infection through genotyping six neutral microsatellites.


RESULTS
In the highlands, 67.4% of the women presented antibodies against Plasmodium falciparum and 9.2% were carrying parasites, at the coast 95.6% and 14.8%, respectively. In the mean, 1.2 clones were detected in infected pregnant woman in the highlands and 1.5 at the coast. A higher level of monoclonal infections was found in the highlands (85.4%) compared to the coast (61.8%). Resistance markers for sulphadoxine-pyrimethamine were present only in two sites.


CONCLUSIONS
Immunity is triggered in Malagasy highland populations when they are infected with malaria parasites, but these populations could also serve as a reservoir for epidemics.
Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany. maiga@bni-hamburg.de.
Oumou
O
Maïga-Ascofaré
University of Antananarivo, Antananarivo, Madagascar. rakrapha13@yahoo.fr.
Raphael
R
Rakotozandrindrainy
Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany. microthewave@hotmail.com.
Mirko
M
Girmann
Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany. hahn@bni-hamburg.de.
Andreas
A
Hahn
University of Antananarivo, Antananarivo, Madagascar. njariharinjaka@yahoo.fr.
Njary
N
Randriamampionona
Justus-Liebig-University, Giessen, Germany. sven@poppert.eu.
Sven
S
Poppert
Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany. may@bni-hamburg.de.
Jürgen
J
May
Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany. schwarznorbert@bni-hamburg.de.
Norbert G
NG
Schwarz
D000293:Adolescent; D000328:Adult; D000913:Antibodies, Protozoan; D000962:Antimalarials / Q000494:pharmacology*; D058345:Asymptomatic Infections / Q000453:epidemiology*; D002738:Chloroquine / Q000494:pharmacology; D004338:Drug Combinations; D004351:Drug Resistance; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008270:Madagascar / Q000453:epidemiology; D008288:Malaria / Q000453:epidemiology* / Q000469:parasitology*; D008875:Middle Aged; D017720:Molecular Epidemiology; D010961:Plasmodium / Q000187:drug effects* / Q000235:genetics*; D011247:Pregnancy; D015995:Prevalence; D015800:Protozoan Proteins / Q000235:genetics; D011739:Pyrimethamine / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D016036:Seroepidemiologic Studies; D013413:Sulfadoxine / Q000494:pharmacology; D055815:Young Adult
D000913:Antibodies, Protozoan; D000962:Antimalarials; D004338:Drug Combinations; D015800:Protozoan Proteins; C001205:fanasil, pyrimethamine drug combination; D013413:Sulfadoxine; D002738:Chloroquine; D011739:Pyrimethamine