Schistosoma mansoni infection reduces the incidence of murine cerebral malaria.
BACKGROUND
Plasmodium and Schistosoma are two of the most common parasites in tropical areas. Deregulation of the immune response to Plasmodium falciparum, characterized by a Th1 response, leads to cerebral malaria (CM), while a Th2 response accompanies chronic schistosomiasis.


METHODS
The development of CM was examined in mice with concomitant Schistosoma mansoni and Plasmodium berghei ANKA infections. The effect of S. mansoni egg antigen injection on disease development and survival was also determined. Cytokine serum levels were estimated using ELISA. Statistical analysis was performed using t-test.


RESULTS
The results demonstrate that concomitant S. mansoni and P. berghei ANKA infection leads to a reduction in CM. This effect is dependent on infection schedule and infecting cercariae number, and is correlated with a Th2 response. Schistosomal egg antigen injection delays the death of Plasmodium-infected mice, indicating immune involvement.


CONCLUSIONS
This research supports previous claims of a protective effect of helminth infection on CM development. The presence of multiple parasitic infections in patients from endemic areas should therefore be carefully noted in clinical trials, and in the development of standard treatment protocols for malaria. Defined helminth antigens may be considered for alleviation of immunopathological symptoms.
Waknine-Grinberg
Judith H
JH
Department of Microbiology and Molecular Genetics, The Hebrew University of Jerusalem, Jerusalem, Israel.
Gold
Daniel
D
Ohayon
Ariel
A
Flescher
Eliezer
E
Heyfets
Alina
A
Doenhoff
Michael J
MJ
Schramm
Gabriele
G
Haas
Helmut
H
Golenser
Jacob
J
D000818:Animals; D016207:Cytokines / Q000097:blood; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D015994:Incidence; D016779:Malaria, Cerebral / Q000150:complications* / Q000453:epidemiology* / Q000469:parasitology / Q000473:pathology; D008297:Male; D051379:Mice; D010962:Plasmodium berghei / Q000276:immunology / Q000472:pathogenicity; D010963:Plasmodium falciparum / Q000276:immunology / Q000472:pathogenicity*; D012555:Schistosomiasis mansoni / Q000150:complications*; D016019:Survival Analysis
D016207:Cytokines