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Endemic Cryptosporidium and Giardia lamblia infections in a Thai orphanage
E N Janoff1, P S Mead, J R Mead
1Veterans Affairs Medical Center, University of Minnesota School of Medicine, Minneapolis.
Insights
Cryptosporidium and Giardia lamblia are common enteric protozoa in Thai orphans. Cryptosporidium infection, often asymptomatic, was linked to poorer acute nutritional status in children.
Area of Science:
- Public Health
- Infectious Diseases
- Pediatrics
Background:
- Institutionalized children are vulnerable to enteric protozoan infections.
- Prevalence and clinical impact of Cryptosporidium and Giardia lamblia in young children in developing countries require further investigation.
Purpose of the Study:
- To determine the prevalence of enteric protozoa, specifically Cryptosporidium and Giardia lamblia, in institutionalized orphans in Bangkok, Thailand.
- To assess the association between these infections and diarrheal symptoms and nutritional status.
- To investigate Cryptosporidium-specific immune responses in the study population.
Main Methods:
- A point prevalence survey was conducted among 205 institutionalized orphans aged 1-61 months in Bangkok.
- Stool samples were analyzed for enteric protozoa.
- Nutritional status was assessed using height-for-age and weight-for-height Z scores.
- Cryptosporidium-specific IgG antibodies were detected using ELISA.
Main Results:
- Cryptosporidium was found in 8% and Giardia lamblia in 20% of children; 1% had both.
- Diarrheal symptoms were infrequent, occurring in a minority of infected and non-infected children.
- Children with Cryptosporidium showed significantly lower acute nutritional status (weight-for-height Z score) compared to those with Giardia lamblia or no parasites.
- High levels of Cryptosporidium-specific IgG antibodies were detected in Thai children, suggesting widespread exposure.
Conclusions:
- Neither Cryptosporidium nor Giardia lamblia infections were consistently associated with acute diarrhea in this cohort.
- Cryptosporidium infection was associated with depressed acute nutritional status, highlighting its clinical significance.
- The high prevalence of Cryptosporidium antibodies indicates frequent exposure and asymptomatic shedding of the parasite in this population.
Abstract:
We conducted a point prevalence survey for enteric protozoa in 205 institutionalized orphans 1-61 months of age in Bangkok, Thailand. Cryptosporidium was identified in 17 children (8%), Giardia lamblia in 42 (20%), and 3 children (1%) had both parasites. At the time of diagnosis, diarrheal symptoms were present in a minority of subjects: 36% of children with Cryptosporidium alone, 10% with G. lamblia alone, and in 20% of those with neither parasite. Although chronic nutritional status (height/age) was similar in all groups, acute nutritional status (weight/height) was lower only in children with Cryptosporidium (Z score = -1.39 +/- 0.13) compared with children with G. lamblia (mean Z score +/- SEM = -0.56 +/- 0.26) or neither parasite (Z score = -0.78 +/- 0.13; P = 0.05). Detectable levels of Cryptosporidium-specific IgG antibodies by ELISA were identified in 15 of 16 Thai children with Cryptosporidium and in 17 of 19 Thai children without Cryptosporidium (mean OD +/- SEM = 1.27 +/- 0.18 vs. 1.06 +/- 0.13, respectively), but in only 1 of 18 sera from toddlers in day-care centers in Denver, CO (OD = 0.128 +/- 0.03). Although neither infection with Cryptosporidium nor G. lamblia was consistently associated with acute diarrheal symptoms, Cryptosporidium was more often associated with depressed acute nutritional status than G. lamblia. The high prevalence of specific antibodies to Cryptosporidium in Thai orphans suggests an association between high rates of exposure with asymptomatic excretion of the parasites.