Household epidemiology of Cryptosporidium parvum infection in an urban community in northeast Brazil.
OBJECTIVE
To examine the transmission of Cryptosporidium infection in households with an identified person with cryptosporidiosis.


METHODS
Prospective cohort study.


METHODS
An urban slum in Fortaleza, Brazil.


METHODS
Thirty-one households with a child less than 3 years of age (index case) who was positive for Cryptosporidium parvum using acid-fast and auramine-stained stool smears.


METHODS
Three stool samples (at 0, 2, and 6 weeks after identification of the index case) and two serum samples (0 and 6 weeks) were collected from each family member in households with an index case of Cryptosporidium infection.


RESULTS
Forty-five percent of index cases of Cryptosporidium infection were associated with persistent (> 14 days) diarrhea. Secondary cases of Cryptosporidium infection were identified either by stool examination or seroconversion in 18 (58%) of 31 households involving 30 persons, yielding an overall transmission rate of 19%. Of the 202 persons in this study with at least one serum sample available for analysis, 191 (94.6%) had evidence of antibodies (either IgM or IgG) to Cryptosporidium.


CONCLUSIONS
Cryptosporidium parvum is highly transmissible and infective in the family setting, with transmission rates similar to other highly infectious enteric pathogens such as Shigella species. These data are cause for added concern because of the rapidly increasing rate of seropositivity for human immunodeficiency virus.
Newman
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RD
Johns Hopkins University School of Medicine, Baltimore, Maryland.
Zu
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Wuhib
T
T
Lima
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AA
Guerrant
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Sears
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CL
D000293:Adolescent; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D003457:Cryptosporidiosis / Q000150:complications / Q000635:transmission*; D016785:Cryptosporidium parvum / Q000302:isolation & purification; D003967:Diarrhea / Q000469:parasitology; D005192:Family Health; D006798:Housing; D006801:Humans; D007223:Infant; D011446:Prospective Studies; D014504:Urban Health