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Unseen infections harming world's children

October 9, 2018
University of Virginia Health System
Children around the world are suffering from unnoticed infections that are stunting their growth and mental development, new research from an international coalition of scientists reveals.

Children around the world are suffering from unnoticed infections that are stunting their growth and mental development, new research from an international coalition of scientists reveals.

Up to 30 percent of children in low-resource countries suffer from stunted growth. Inadequate nutrition and diarrhea have long been blamed, but scientists have, until now, been unable to explain a large percentage of stunting cases. Two new studies, however, show that a tremendous number of children with no signs of diarrhea are carrying harmful infections. These infections ultimately prevent them from reaching their full potential and perpetuate a vicious cycle of poverty.

"If we're just targeting diarrhea, that may not be enough. We need to be addressing these asymptomatic exposures as well," said researcher Liz Rogawski McQuade, PhD, of the University of Virginia School of Medicine. "If we could have interventions against just four pathogens, we would expect an improvement in growth that's similar to what has been seen for nutritional interventions in similar settings. This puts pathogen exposure, in terms of importance, on the same level as nutrition, which in the past has been considered the main reason for poor growth."

Childhood Infections

The researchers examined more than 44,000 stool samples from children in eight countries: Pakistan, India, Nepal, Bangladesh, Tanzania, South Africa, Peru and Brazil. They analyzed the samples using highly sensitive molecular testing -- testing much more sensitive than that available in the past -- to determine whether the children were carrying harmful infections. They found that four main pathogens were widely present in asymptomatic children: Shigella bacteria, Campylobacter bacteria, enteroaggregative E. coli bacteria and the giardia parasite. More than 95 percent of the children tested positive for at least one pathogen.

"It was surprising that these infections without diarrhea were so common, and that they seemed to explain a large amount of the stunting," said researcher Eric R. Houpt, MD, of UVA's Division of Infectious Diseases and International Health. "The challenge now will be to see if we can reduce these four."

The dangers of Shigella are well known, as it is associated with bloody diarrhea. But the new research suggests that it may be an even greater threat than expected. The researchers examined stool samples from children with diarrhea, and they found that Shigella was common even among children with diarrhea that was not bloody. It was especially common in the second year of life.

"Existing international guidelines recommend that only bloody diarrhea needs to be treated with antibiotics in children in these settings, a recommendation that is designed to target the treatment of shigellosis" said researcher James A. Platts-Mills, MD, of UVA's Department of Medicine. "The frequent detection of Shigella from non-bloody diarrhea, as well as the strong association between Shigella infection and poor growth, suggest that those guidelines need to be revisited."

Asymptomatic Infections

Houpt noted that childhood infections have lasting effects. "Stunting means children aren't growing and means that they get sick more easily," he said. "They don't do as well in school, and this can trap them in poverty."

Finding ways to address these infections among the world's children could have tremendous benefits. Vaccines, for example, are being developed for both Shigella and Campylobacter, noted McQuade, of UVA's Department of Public Health Sciences and UVA's Division of Infectious Diseases and International Health.

"We've made huge gains in diarrhea around the world, and the mortality rate has decreased very rapidly. Both are wonderful, but there is still a lot of room for improvement, and we really need to target these subclinical infections," she said. "We think that these early-life experiences are extremely important for child cognitive development, which is essential for their future earning potential and ... paramount to health."

UVA is now conducting a clinical trial in Tanzania to determine if treating these asymptomatic infections will reduce stunting without significantly increasing antibiotic resistance.

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Materials provided by University of Virginia Health System. Note: Content may be edited for style and length.

Journal Reference:

  1. Elizabeth T Rogawski, Jie Liu, James A Platts-Mills, Furqan Kabir, Paphavee Lertsethtakarn, Mery Siguas, Shaila S Khan, Ira Praharaj, Arinao Murei, Rosemary Nshama, Buliga Mujaga, Alexandre Havt, Irene A Maciel, Darwin J Operario, Mami Taniuchi, Jean Gratz, Suzanne E Stroup, James H Roberts, Adil Kalam, Fatima Aziz, Shahida Qureshi, M Ohedul Islam, Pimmada Sakpaisal, Sasikorn Silapong, Pablo P Yori, Revathi Rajendiran, Blossom Benny, Monica McGrath, Jessica C Seidman, Dennis Lang, Michael Gottlieb, Richard L Guerrant, Aldo A M Lima, Jose Paulo Leite, Amidou Samie, Pascal O Bessong, Nicola Page, Ladaporn Bodhidatta, Carl Mason, Sanjaya Shrestha, Ireen Kiwelu, Estomih R Mduma, Najeeha T Iqbal, Zulfiqar A Bhutta, Tahmeed Ahmed, Rashidul Haque, Gagandeep Kang, Margaret N Kosek, Eric R Houpt, Angel Mendez Acosta, Rosa Rios de Burga, Cesar Banda Chavez, Julian Torres Flores, Maribel Paredes Olotegui, Silvia Rengifo Pinedo, Dixner Rengifo Trigoso, Angel Orbe Vasquez, Imran Ahmed, Didar Alam, Asad Ali, Muneera Rasheed, Sajid Soofi, Ali Turab, Aisha Yousafzai, Anita KM Zaidi, Binob Shrestha, Bishnu Bahadur Rayamajhi, Tor Strand, Geetha Ammu, Sudhir Babji, Anuradha Bose, Ajila T George, Dinesh Hariraju, M. Steffi Jennifer, Sushil John, Shiny Kaki, Priyadarshani Karunakaran, Beena Koshy, Robin P Lazarus, Jayaprakash Muliyil, Preethi Ragasudha, Mohan Venkata Raghava, Sophy Raju, Anup Ramachandran, Rakhi Ramadas, Karthikeyan Ramanujam, Anuradha Rose, Reeba Roshan, Srujan L Sharma, Shanmuga Sundaram, Rahul J Thomas, William K Pan, Ramya Ambikapathi, J Daniel Carreon, Viyada Doan, Christel Hoest, Stacey Knobler, Mark A Miller, Stephanie Psaki, Zeba Rasmussen, Stephanie A Richard, Karen H Tountas, Erling Svensen, Caroline Amour, Eliwaza Bayyo, Regisiana Mvungi, John Pascal, Ladislaus Yarrot, Leah Barrett, Rebecca Dillingham, William A Petri, Rebecca Scharf, AM Shamsir Ahmed, Md Ashraful Alam, Umma Haque, Md Iqbal Hossain, Munirul Islam, Mustafa Mahfuz, Dinesh Mondal, Baitun Nahar, Fahmida Tofail, Ram Krishna Chandyo, Prakash Sunder Shrestha, Rita Shrestha, Manjeswori Ulak, Aubrey Bauck, Robert Black, Laura Caulfield, William Checkley, Gwenyth Lee, Kerry Schulze, Samuel Scott, Laura E Murray-Kolb, A Catharine Ross, Barbara Schaefer, Suzanne Simons, Laura Pendergast, Cláudia B Abreu, Hilda Costa, Alessandra Di Moura, José Quirino Filho, Álvaro M Leite, Noélia L Lima, Ila F Lima, Bruna LL Maciel, Pedro HQS Medeiros, Milena Moraes, Francisco S Mota, Reinaldo B Oriá, Josiane Quetz, Alberto M Soares, Rosa MS Mota, Crystal L Patil, Cloupas Mahopo, Angelina Maphula, Emanuel Nyathi. Use of quantitative molecular diagnostic methods to investigate the effect of enteropathogen infections on linear growth in children in low-resource settings: longitudinal analysis of results from the MAL-ED cohort study. The Lancet Global Health, 2018; DOI: 10.1016/S2214-109X(18)30351-6

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University of Virginia Health System. "Unseen infections harming world's children." ScienceDaily. ScienceDaily, 9 October 2018. <>.
University of Virginia Health System. (2018, October 9). Unseen infections harming world's children. ScienceDaily. Retrieved December 1, 2023 from
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