Children infected even just once with a certain type of waterborne parasite are nearly three times as likely to suffer from moderate or severe stunted growth by age 2 than those who are not – regardless of whether their infection made them feel sick, new Johns Hopkins Bloomberg School of Public Health-led research suggests.
The researchers, publishing May 4 in the journal PLOS Neglected Tropical Diseases, found that three of every four children studied in a slum on the outskirts of the capital of Bangladesh experienced at least one Cryptosporidium infection in the first 24 months of life. One in four of the 302 infected children experienced the severe diarrhea that is associated with the parasite, while the other 72 percent were infected with Cryptosporidium but had no symptoms at all.
Despite a lack of symptoms, more than half of the children experienced stunted growth in the first two years of life, leading to irreversible damage and contributing to poor cognitive development, poor educational performance and reduced earning potential in adulthood, trapping individuals in a lifetime of poverty. Worldwide, an estimated 178 million children under 5 suffer from stunted growth, primarily in lower-income countries. The spread of Cryptosporidium can be blamed on a lack of access to clean drinking water and proper toilets. It is resistant to chlorine, which is often used to clean water.
“It has been thought that the diarrhea that results from Cryptosporidium infections was causing the dehydration and malnutrition that can lead to stunted growth,” says the study’s leader Dr. Poonum Korpe, an assistant scientist in the department of epidemiology at the Bloomberg School. “This study suggests that while diarrhea is certainly a problem, infection with the parasite itself – even if there are no diarrheal symptoms – is causing the malnutrition. These children don’t even get sick and their growth is stunted. We think it’s possible that the parasite is damaging the gut at this early age, making absorption of vital nutrients more difficult.”