Synergistic associations between hookworm and other helminth species in a rural community in Brazil.
OBJECTIVE
To identify possible synergistic associations of hookworm and other helminths.


METHODS
Cross-sectional survey of all households within 10 km2 of Americaninhas, a rural community in Minas Gerais, Brazil. We determined the prevalence and intensity of single and multiple helminth species infection in an age-stratified sample of 1332 individuals from 335 households.


RESULTS
Hookworm was the most prevalent helminth infection (68.2%), followed by Ascaris lumbricoides (48.8%) and Schistosoma mansoni (45.3%). Overall, 60.6% of individuals harboured mixed helminth infections. Multivariate analysis indicated significant positive associations for co-infection with hookworm and S. mansoni and for co-infection with hookworm and A. lumbricoides. Co-infections with hookworm and A. lumbricoides resulted in higher egg counts for both, suggesting a synergistic relationship between these species, although, we found important age differences in this relationship. However, the intensity of S. mansoni or A. lumbricoides co-infection did not differ from that of mono-infection.


CONCLUSIONS
These results have implications for the epidemiology, immunology and control of multiple helminth infections. More research is needed to examine the rates of re-infection and immune responses after chemotherapy, and to what extent the effects of polyparasitism are altered by chemotherapy.
Fleming
Fiona M
FM
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, UK.
Brooker
Simon
S
Geiger
Stefan M
SM
Caldas
Iramaya R
IR
Correa-Oliveira
Rodrigo
R
Hotez
Peter J
PJ
Bethony
Jeffrey M
JM
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000818:Animals; D001196:Ascariasis / Q000453:epidemiology / Q000469:parasitology; D017164:Ascaris lumbricoides / Q000302:isolation & purification; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006373:Helminthiasis / Q000453:epidemiology / Q000469:parasitology*; D006725:Hookworm Infections / Q000453:epidemiology / Q000469:parasitology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010270:Parasite Egg Count; D011159:Population Surveillance; D015995:Prevalence; D012423:Rural Health; D012555:Schistosomiasis mansoni / Q000453:epidemiology