Nav: Home

Children in developing world infected with parasite may be more prone

May 04, 2016

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 the age of two 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 Poonum Korpe, MD, 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."

For the study, Korpe worked with collaborators from the University of Virginia and the International Centre for Diarrhoeal Disease Research in Bangladesh. The researchers followed 392 children from a slum called Mirpur from birth until the age of two. Twice a week, families were visited by researchers who asked questions about the child's health, monitored growth and collected blood and stool samples, which were later tested for a variety of bacteria and parasites.

According to the World Health Organization definition, children are considered stunted if their height-to-age ratio falls under what is considered the norm. The researchers found that by the age of two, nearly 30 percent of the children in Mirpur met the WHO definition for mild stunting, nearly 36 percent for moderate stunting and 21 percent for severe stunting.

While the researchers aren't certain exactly why children without diarrhea still experienced stunting, they suspect that the appearance of the larva-like parasite in the intestines may be causing permanent damage to the intestines' ability to absorb nutrients. Recent studies of programs that provide adequate food and supplementation to families in need in low-income countries have surprised researchers in that these interventions have not had the impact on malnutrition that they expected.

"Those interventions have not been as successful as we thought they would be," Korpe says. "Malnutrition is more than just an issue of food insecurity. This study suggests a possible reason why. It could be the first step in recognizing that gut infections may be the real problem. But we have a lot of work to do to figure this all out."

According to a 2008 analysis by a separate Johns Hopkins Bloomberg School of Public Health group, 21 percent of deaths in children younger than five are attributable to malnutrition worldwide.

The infection occurs all over the developing world, but there have been sporadic outbreaks in the United States, typically in the summer when a pool is contaminated with the Cryptosporidium parasite.

Korpe says that the focus needs to be on interrupting the spread of infection as well as developing vaccines and treatments.

"These children weren't born stunted," she says. "Something happened in the environment that's doing this to them."
-end-
"Natural history of Cryptosporidiosis in a longitudinal study of slum-dwelling Bangladeshi children: association with severe malnutrition" was written by Poonum S. Korpe; Rashidul Haque; Carol Gilchrist; Cristian Valencia; Feiyang Niu; Miao Lu; Jennie Z. Ma; Sarah E. Petri; Daniel Reichman; Mamun Kabir; Priya Duggal; and William A. Petri, Jr.

The study was supported by grants from the National Institutes of Health's National Institute of Allergy and Infectious Diseases (5R01AI043596 and 5K23AI108790).

Johns Hopkins University Bloomberg School of Public Health

Related Public Health Articles:

Public health guidelines aim to lower health risks of cannabis use
Canada's Lower-Risk Cannabis Use Guidelines, released today with the endorsement of key medical and public health organizations, provide 10 science-based recommendations to enable cannabis users to reduce their health risks.
Study clusters health behavior groups to broaden public health interventions
A new study led by a University of Kansas researcher has used national health statistics and identified how to cluster seven health behavior groups based on smoking status, alcohol use, physical activity, physician visits and flu vaccination are associated with mortality.
Public health experts celebrate 30 years of CDC's prevention research solutions for communities with health disparities
It has been 30 years since CDC created the Prevention Research Centers (PRC) Program, currently a network of 26 academic institutions across the US dedicated to moving new discoveries into the communities that need them.
Public health experts support federally mandated smoke-free public housing
In response to a new federal rule mandating smoke-free policies in federally funded public housing authorities, three public health experts applaud the efforts of the US Department of Housing and Urban Development to protect nonsmoking residents from the harmful effects of tobacco exposure.
The Lancet Public Health: UK soft drinks industry levy estimated to have significant health benefits, especially among children
The UK soft drinks industry levy, due to be introduced in April 2018, is estimated to have significant health benefits, especially among children, according to the first study to estimate its health impact, published in The Lancet Public Health.
Social sciences & health innovations: Making health public
The international conference 'Social Sciences & Health Innovations: Making Health Public' is the third event organized as a collaborative endeavor between Maastricht University, the Netherlands, and Tomsk State University, the Russian Federation, with participation from Siberian State Medical University (the Russian Federation).
Columbia Mailman School Awards Public Health Prize to NYC Health Commissioner Dr. Mary T.
Dr. Mary T. Bassett, Commissioner of the New York City Department of Health and Mental Hygiene, was awarded the Frank A.
Poor health literacy a public health issue
America's poor record on health literacy is a public health issue, but one that can be fixed -- not by logging onto the internet but by increased interaction with your fellow human beings, a Michigan State University researcher argues.
Despite health law's bow to prevention, US public health funding is dropping: AJPH study
Although the language of the Affordable Care Act emphasizes disease prevention -- for example, mandating insurance coverage of clinical preventive services such as mammograms -- funding for public health programs to prevent disease have actually been declining in recent years.
'Chemsex' needs to become a public health priority
Chemsex -- sex under the influence of illegal drugs -- needs to become a public health priority, argue experts in The BMJ this week.

Related Public Health Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".