Half the children in Guinea-Bissau have intestinal parasites

Environment and sustainability 4. jul 2019 2 min Ph.d.-studerende, Cand.med. Sebastian Leicht von Huth Written by Morten Busch

The researchers set out to study the immune system of children with intestinal worms in Guinea-Bissau. However, they were surprised when they investigated the samples from sick children. Fewer children than expected had intestinal worms, but half had intestinal parasites. Most surprisingly, the researchers also found that the same percentage of healthy children had the parasites. The researchers now aim to identify which children have harmful parasites and which children have parasites that may even be beneficial.

Guinea-Bissau is one of the poorest countries in the world, and this affects health: 55 of 1000 children die at birth, people with diabetes are rarely diagnosed and treated, and cancer is simply a death sentence. Sewerage and sanitation are also incredibly poor, making infections an everyday event. Researchers have now investigated one of the worst plagues affecting the country’s children – intestinal parasites that lead to malnutrition, impaired quality of life and cognitive problems.

”Our goal was to investigate the immune system of children with intestinal worms so we can diagnose and treat them. Fortunately, treatment efforts in recent years appear to have significantly reduced the proliferation of these worms. Nevertheless, half the children had intestinal protozoa. We will now develop a method to identify the children who need treatment and the children to whom the parasites are harmless or even beneficial,” explains a main author, Sebastian Leicht von Huth, Visiting Researcher, Department of Cancer and Inflammation Research, University of Southern Denmark, Odense.

A big surprise

The research is part of the Bandim Health Project that has operated since the late 1970s, in which researchers from Statens Serum Institut and various universities in Denmark monitor more than 200,000 people in urban and rural areas of Guinea-Bissau, including the effects of vaccines, vitamin supplements and other measures to improve health.

“The initial plan was to examine some of the signalling molecules in the immune system of children with intestinal worms. We were pleased to observe, however, that the policy of treating all children in a school simultaneously for intestinal worms had worked really well. Nevertheless, our tests showed that half the children had intestinal parasites.”

These pathogenic protozoa were Entamoeba histolytica, Entamoeba dispar and Giardia lamblia. The researchers found that many of the sick children who came to the research clinic seeking healthcare had these intestinal parasites. However, when the researchers examined children from a comparison population, they got a big surprise.

“The same percentage of children from the comparison population had these intestinal protozoa. However, since these children did not have any symptoms, this suggests that the protozoa they had do not make them sick.”

Important to wait for the results

Unfortunately, one of these three protozoa is pathogenic. Entamoeba histolytica can cause amoebic dysentery. However, the researchers analysed stool samples by microscopy and could therefore not determine how many children had Entamoeba histolytica and how many had the harmless Entamoeba dispar.

“In the next project, we will examine the children using a polymerase chain reaction test to differentiate between Entamoeba histolytica and Entamoeba dispar. If we succeed, we can focus on treating the children with Entamoeba histolytica.”

An obvious idea would be treating children collectively, similar to how the intestinal worms were combated. However, the treatment for protozoa is much more complicated because it has to be given several days in a row, whereas children with intestinal worms can be treated only once. In addition, according to Sebastian Leicht von Huth, there is another good reason to wait for the results instead of just starting to treat all children with protozoa.

”Protozoa can actually be beneficial in some cases. The harmless protozoa may even help to keep the children healthy. In any case, it is remarkable that so many children have them without getting sick. So the most important thing initially is to develop a method that can identify children with Entamoeba histolytica.”

Prevalence and potential risk factors for gastrointestinal parasitic infections in children in urban Bissau, Guinea-Bissau” has been published in Transactions of the Royal Society of Tropical Medicine & Hygiene. The study received funding from the Odense University Hospital Free Research Fund, Aase and Ejnar Danielsen Foundation A.P. Møller  Foundation of the Advancement of Medical Science and others. The Novo Nordisk Foundation has frequently supported the Bandim Health Project at Statens Serum Institut. In 2018, the Foundation awarded a grant to co-author Uffe Holmskov, Department of Molecular Medicine, University of Southern Denmark, Odense for the project FIBCD1-mediated Signal Transduction Pathways Regulate Gut Inflammation.

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