How worm infestion affects children’s IQ

What can you do to make your kids smarter? Keeping them healthy might help. In this report by Sade Oguntola, experts say children heavily affected by everything from intestinal worms to bacteria and viruses, devote more energy to fighting off infection ends up with the lowest average IQs.


It is common to see children playing feet away from dirty pools of water, playing football barefooted or fetching drinking water from well exposed to raw sewage having problems with worm an intestinal parasite that thrives on extreme poverty.

Worm infestation is a major problem in children due to bad hygienic conditions. It is one of the major causes of childhood malnutrition, anemia, stunted physical and mental growth in children, especially when hookworm infestation is present.

People with hookworm release eggs through excrement; in areas with poor sanitation or open sewers, they end up on the ground, where they turn into microscopic, infectious larvae that dig into human skin when people walk by.

Hookworm enters the body through the skin, usually through the soles of bare feet, and travels around the body until it attaches itself to the small intestine where it proceeds to suck the blood of its host.

Over months or years, it causes iron deficiency and anemia, weight loss, interfere with absorption of critical nutrients, tiredness and suppresses the immune system as well as permanently stunt the physical and intellectual development of infected children.

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Three species of hookworms can infect humans. People most commonly infected are exposed to the worm through contaminated soil or food.

Unfortunately, hookworm infection, even at low levels, could cause cognitive impairments earlier than thought. This finding, published in scientific reports, indicated that these parasites have a real impact on cognition, independent of long-term developmental delays that can be observed within a very short period.

Cognitive impairment is when a person has trouble remembering new things, concentrating or making decisions that affect their everyday life. It may be present at birth or can occur at any point in a person’s lifespan.

Cognitive impairment which ranges from mild to severe can include loss of higher reasoning, forgetfulness, learning disabilities, concentration difficulties, decreased intelligence and other reductions in mental functions.

Other effects of hookworm infection include itchy rash, cough, fever, bloody sputum, and loss of appetite, nausea, vomiting, diarrhea, abdominal discomfort, paleness, fatigue and blood in the stool.

Professor Akinbami, a pediatrician, added:“hookworm infestation can make the child lose blood, whose role is it to carry oxygen and nutrients around the body.

“Some worms also damage the lining of the intestine, thereby affecting the absorption of nutrients from food into the body. Worms that cause diarrhea also make the child lose nutrient through the faeces that are passed. So, there is no way the person will not be malnourished, more so if it is long-standing.”

Dr Bankole Kuti, a consultant pediatrician, Obafemi Awolowo University Teaching Hospital Complex (OAUTHC), Ile-Ife, Osun State, stated that massive hookworm infestation can contribute to cognitive impairment in children.

According to him, “the worms cause micro bleedings in the gut, which makes the child lose a lot of blood and have anemia, particularly iron-deficiency anemia. Iron and blood are generally needed for cognition.

“Of course, when they detach from one point and get attached to another, the child can still bleed and lose lots of micronutrients which are needed for brain growth and development from such areas.”

Dr Kuti stated that worms generally proliferate in hundreds and thousands, partaking of the already digested food the child needs for nourishment while they reside in the small intestine, thereby contributing to malnutrition and cognitive problem and failure to attain developmental milestones.

Ironically, he stated that open defecation which leaves children exposed to eggs of worm in faeces is still a major problem in Nigeria just as eating unwashed fruits and vegetables, picked pieces of food items from the floor and poor hand washing habits.

Dr Kuti added: “Faeces, if it is openly done, can find its way into wells through runoffs. So, when such water is consumed, the eggs taken in will grow into a worm and continue to proliferate in the body and it will cause a lot of havoc. A female hookworm can lay up to 10,000 eggs in a single day.

“Some worms migrate from one part of the body to another. For instance, roundworms can migrate from the lungs to the liver, leaving the persons with asthma symptoms.

“Worm infestation is a big problem. So, it is advised that children should be de-wormed at least once every six months to reduce their worm load.”

In order to study the short-term effect of hookworm infection on brain function in a controlled laboratory setting, the researchers had developed a series of experiments to test spatial memory and object memory in rodents.

According to them, “These parasites have a real impact on brain function in rodents, independent of long-term developmental delays that can be observed very quickly after the initial infection.

“More importantly, the study supported the importance and urgency of global de-worming efforts to eliminate hookworm in order to alleviate poverty and save the brains of impoverished children.”

Children with hookworms were plagued with attention deficit disorders and lower IQ, and the infected often had strange food cravings for dirt, clay, paper, and chalk.

Studies done in different parts of Nigeria revealed a high prevalence of worm infection among children. Prevalence rates reaching 49.7 per cent among children aged 1-5 years in Calabar; 92.8 per cent among 1-4 years, 69 per cent among 5-9 years, 34.6 per cent among 10-15 years in Ibadan; 60.7 per cent among 1-5 years, 25.9 per cent among 6-10 years and 13.4 per cent among 11-15 years in Edo state [19] have been reported.

In 2018, researchers in a systematic review and meta-analysis published in BMC, worm infestation were observed more among children within community settings and school-age children. Roundworm was the most prevalent species (44.6 per cent).

Moreover, studies suggest that worldwide differences in intelligence can be explained by disparities in infectious disease. The researchers found that countries most heavily affected by infectious diseases generally had the lowest average IQs.

They propose that these illnesses hinder children’s brain development, though their conclusion is gathering mixed reviews.

Several groups have attempted to explain the pattern. For instance, researchers at the University of New Mexico, Albuquerque propose that low IQ is tied to the toll of infectious diseases.

Their idea, which the researchers call the “parasite-stress hypothesis,” is that children who contract “parasites,” which they define to include everything from intestinal worms to bacteria and viruses, devote more energy to fighting off infection. As a result, they have less energy available for brain development.

The researchers in the Proceedings of the Royal Society B, analysed independently factors such as nutrition, literacy, education, gross domestic product, and temperature that are linked to IQ.

They found that infectious disease burden was more closely correlated to average IQ than the other variables. Parasites alone account for 67per cent of the worldwide variation in intelligence.

Moreover, researchers in the September 2019 online BMC Public Health journal, demonstrated the association between intestinal worm infections and stunting appeared to be largely mediated via low IQ.

This study was in line with an early study that the burden of children malnutrition could be aggravated by infestation with hookworms.

In this survey among 2179 children aged 9–11 years old in Guizhou Province, China, the researchers had estimate the associations of intestinal worm infection with thinness, underweight, and stunting.

Parts of children were infected by intestinal worms (41.85per cent). Stunting (28 per cent ), low memory IQ (87.52 per cent ), and low process IQ (62.59 per cent ) were also highly prevalent.

More importantly, stunting in early childhood was associated with cognitive and educational deficits in late adolescence. Likewise, a previous study reported the association between intelligence and diet might be beneficial to children’s cognitive development.


Nigerian Tribune

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