Asymptomatic and symptomatic cryptosporidiosis: their acute effect on weight gain in Peruvian children

Abstract

This study investigated whether a child's first infection with Cryptosporidium parvum had an acute effect on weight gain. Specifically, the authors compared monthly rates of weight gain between C. parvum-infected and noninfected children. Over a 2-year period (1989-1991), a cohort of Peruvian children aged 0-3 months at recruitment were followed twice weekly for assessment of daily diarrheal status, weekly for C. parvum stool examinations, and monthly for anthropometric measurements. Data on 207 children permitted the authors to examine the effect of C. parvum infection on weight gain. During the 2-year study period, 45% (94/207) of the children became infected with C. parvum for the first time. Weight gain intervals in 57 of the 94 infected children met criteria for analysis. Of these, 63 percent (36/57) were asymptomatic (i.e., had no diarrhea). On average, children with symptomatic cryptosporidiosis gained (i.e., grew) 342 g less (95% confidence interval 167-517) during the first month of infection than did children without diarrhea who were not yet infected. The effect of asymptomatic cryptosporidiosis was less severe: On average, children with asymptomatic infection gained 162 g less (95% confidence interval 27-297) during the first month of infection than did children without diarrhea who were not yet infected. Symptomatic cryptosporidiosis retarded weight gain more than did asymptomatic cryptosporidiosis, but the latter was twice as common. Since asymptomatic cryptosporidiosis is more prevalent, it may have more of an overall adverse effect on child growth in the community than symptomatic cryptosporidiosis.

PIP: During September 1989-November 1991 in Peru, 207 infants, 0-3 months old at enrollment and living in a periurban shanty town in Lima, were followed to determine whether a child's first infection with Cryptosporidium parvum had an adverse effect on weight gain during the first month of infection and whether poor nutritional status was a risk factor for C. parvum. Infection with C. parvum occurred at least once in 45% (97) of the infants. Median age at onset of a first C. parvum infection was 16 months. The growth interval of only 57 (61%) of C. parvum infected children was evaluated. 36 (63%) children were asymptomatic. The remaining 21 infected children had diarrhea. Children with cryptosporidiosis, whether symptomatic or asymptomatic, gained less weight during the first month of infection than children without cryptosporidiosis. Children with symptomatic cryptosporidiosis gained 184 g less weight during the first month of infection than did children with asymptomatic cryptosporidiosis. Children with symptomatic cryptosporidiosis gained 342 g less during the first month of infection than did children who were not infected with C. parvum and did not have diarrhea. Children with asymptomatic cryptosporidiosis gained 162 g less during the first month of infection than did children who were not infected with C. parvum and did not have diarrhea. The adverse effect of C. parvum on weight gain was strongest in children younger than 12 months. Neither wasting nor underweight was a significant risk factor for C. parvum infection. Stunting tended to increase the risk of C. parvum infection but the effect was not statistically significant. These findings show that C. parvum infection has an adverse effect on growth. Asymptomatic cryptosporidiosis is of special concern, since it was more prevalent and thus probably would have more of an overall adverse effect on child growth in the community.