NEW YORK (Reuters Health) – About one in four children adopted in the US from outside the country have at least one intestinal parasite, and while the likelihood of pathogen recovery is not related to gastrointestinal symptoms, it is significantly increased with evaluation of multiple stool specimens.

Those are some of the findings from a study of intestinal parasite screening in internationally adopted children, reported in the September issue of Pediatrics.

“On the basis of our results,” the authors advise, “American Academy of Pediatrics recommendations should be revisited so that 3 stool specimens are submitted and evaluated for all internationally adopted children on arrival to the United States, regardless of gastrointestinal symptoms.”

Dr. Mary Allen Staat, at Cincinnati Children’s Hospital Medical Center, Ohio and colleagues note that nearly 200,000 children were internationally adopted in the US over the past 10 years. Currently the American Academy of Pediatrics recommends that such children should be screened for intestinal parasites as part of a comprehensive evaluation. For this, up to four stool specimens are recommended, but just one sample is deemed sufficient for asymptomatic children.

To examine risk factors for parasite infection and the value of multiple stool specimens, the team studied data on 1042 children screened within 120 days of arrival in the US.

Overall, 279 of the children (27%) had at least one pathogenic parasite, the investigators found. Most common were the protozoa Giardia intestinalis (19%), Blastocystis hominis (10%), Dientamoeba fragilis (5%), and Entamoeba histolytica (1%), followed by a lesser prevalence of various helminths.

The prevalence of pathogens was lowest in children from South Korea and Guatemala and highest in those from Ethiopia and Ukraine, according to the report.

Age and institutionalization were also risk factors. Just 7% of children less than 1 year of age had a pathogen compared with 40% of older children; and rates were 4% in non-institutionalized children versus 34% in those who had been in an institution.

On the other hand, as mentioned, findings were no different in children with or without GI symptoms of diarrhea or frequent stools.

“Parents were asked to collect 3 stools 48 to 72 hours apart,” the researchers explain, and this provided them with the opportunity to see if evaluating multiple stool specimens increased the yield of parasite identification. They found that it did.

Specifically, in children found to be infected, the probability of identifying any pathogen in one specimen was 79%; with two specimens it rose to 92%; and with three, it was 100%.

Based on these findings, Dr. Staat and colleagues conclude, “All internationally adopted children should have at least 3 stools examined to identify intestinal parasites.”

They add, “Our results provide data for the development of evidence-based guidelines for intestinal parasite screening in internationally adopted children.”

Reference:
Intestinal Parasite Screening in Internationally Adopted Children: Importance of Multiple Stool Specimens
Pediatrics 2011;128:e000