Seroprevalence of malaria in inhabitants of the urban zone of Antananarivo, Madagascar.
BACKGROUND
Antananarivo, the capital of Madagascar, is located at an altitude of over 1,200 m. The environment at this altitude is not particularly favourable to malaria transmission, but malaria nonetheless remains a major public health problem. The aim of this study was to evaluate exposure to malaria in the urban population of Antananarivo, by measuring the specific seroprevalence of Plasmodium falciparum.


METHODS
Serological studies specific for P. falciparum were carried out with an indirect fluorescent antibody test (IFAT). In a representative population of Antananarivo, 1,059 healthy volunteers were interviewed and serum samples were taken.


RESULTS
The seroprevalence of IgG+IgA+IgM was 56.1% and that of IgM was 5.9%. The major risk factor associated with a positive IgG+IgA+IgM IFAT was travel outside Antananarivo, whether in the central highlands or on the coast. The abundance of rice fields in certain urban districts was not associated with a higher seroprevalence.


CONCLUSIONS
Malaria transmission levels are low in Antananarivo, but seroprevalence is high. Humans come into contact with the parasite primarily when travelling outside the city. Further studies are required to identify indigenous risk factors and intra-city variations more clearly.
Domarle
Olivier
O
Institut Pasteur de Madagascar, Antananarivo, Madagascar. domarle@pasteur.mg
Razakandrainibe
Romy
R
Rakotomalala
Emma
E
Jolivet
Laurence
L
Randremanana
Rindra Vatosoa
RV
Rakotomanana
Fanjasoa
F
Ramarokoto
Charles Emile
CE
Soares
Jean-Louis
JL
Ariey
Frédéric
F
D000293:Adolescent; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D002648:Child; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008270:Madagascar / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000097:blood* / Q000453:epidemiology* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000276:immunology; D016036:Seroepidemiologic Studies; D014504:Urban Health / Q000706:statistics & numerical data*; D014505:Urban Population
D000913:Antibodies, Protozoan; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M