Functional significance of low-intensity polyparasite helminth infections in anemia.
BACKGROUND
We wanted to quantify the impact that polyparasite infections, including multiple concurrent low-intensity infections, have on anemia.


METHODS
Three stool samples were collected and read in duplicate by the Kato-Katz method in a cross-sectional sample of 507 children from Leyte, The Philippines. The number of eggs per gram of stool was used to define 3 infection intensity categories--uninfected, low, and moderate/high (M+)--for 3 geohelminth species and Schistosomiasis japonicum. Four polyparasite infection profiles were defined in addition to a reference profile that consisted of either no infections or low-intensity infection with only 1 parasite. Logistic regression models were used to quantify the effect that polyparasitism has on anemia (hemoglobin level <11 g/dL).


RESULTS
The odds of having anemia in children with low-intensity polyparasite infections were nearly 5-fold higher (P = .052) than those in children with the reference profile. The odds of having anemia in children infected with 3 or 4 parasite species at M+ intensity were 8-fold greater than those in children with the reference profile (P < .001).


CONCLUSIONS
Low-intensity polyparasite infections were associated with increased odds of having anemia. In most parts of the developing world, concurrent infection with multiple parasite species is more common than single-species infections. This study suggests that concurrent low-intensity infections with multiple parasite species result in clinically significant morbidity.
Ezeamama
Amara E
AE
International Health Institute, Brown University, Providence, RI 02912, USA. Amara_Ezeamama@brown.edu
Friedman
Jennifer F
JF
Olveda
Remigio M
RM
Acosta
Luz P
LP
Kurtis
Jonathan D
JD
Mor
Vincent
V
McGarvey
Stephen T
ST
D000293:Adolescent; D000740:Anemia / Q000150:complications* / Q000453:epidemiology; D000818:Animals; D001196:Ascariasis / Q000150:complications / Q000453:epidemiology / Q000469:parasitology; D002648:Child; D003430:Cross-Sectional Studies; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009332:Necatoriasis / Q000150:complications / Q000453:epidemiology / Q000469:parasitology; D009348:Nematoda / Q000145:classification / Q000302:isolation & purification; D009349:Nematode Infections / Q000150:complications* / Q000453:epidemiology / Q000469:parasitology*; D010270:Parasite Egg Count; D010679:Philippines / Q000453:epidemiology; D012549:Schistosoma japonicum / Q000145:classification / Q000302:isolation & purification; D012554:Schistosomiasis japonica / Q000150:complications* / Q000453:epidemiology / Q000469:parasitology*; D014257:Trichuriasis / Q000150:complications / Q000453:epidemiology / Q000469:parasitology