Effects on Children
Intestinal roundworm infections are the leading cause of disease burden in children worldwide. Although intestinal roundworms do not kill children, the cumulative effects of the parasites in the hundreds of millions of infected children over time are devastating.
Intestinal roundworms cause physical stunting, decreased mental skills, and weakened immune responses and are thus the perfect storm for a growing child. These parasites decrease a child’s chances to one day lead a productive adult life and work to trap large populations in poverty.
THE PERFECT STORM FOR DISABLING A CHILD’S DEVELOPMENT:
1. Growth stunting. Children who grow up with intestinal roundworm infections are stunted physically (e.g., shorter than normal). A study from a Northeast Brazil shantytown found that early childhood (0-2 yr) intestinal roundworm infections resulted in growth stunting of 4.6 cm (nearly 2 inches) by age 7. A large-scale review of medical literature revealed that deworming children results in significantly improved growth. If the children remain untreated, growth stunting can be permanent. (references 1)
2. Cognitive stunting and lower cognitive functioning. Children who grow up with intestinal roundworm infections develop significantly lower cognitive skills and functions. For example, school-aged children in Indonesia infected with hookworms performedsignificantly worse than uninfected children on 6 of 14 different measures of cognitive and motor skills. Intestinal roundworm infections were found to result in decreased learning skills in Tanzanian schoolchildren. (references 2)
3. Weakened immune responses and overall health. Intestinal roundworm infections lead to altered immune responsesthat can lead to higher viral titers to HIV/AIDS, higher increases in prevalence of malaria parasites, and may be associated with promoting active tuberculosis. To add insult to injury, intestinal roundworms decrease the effectiveness of vaccines to protect children from future diseases. Intestinal roundworm infections also cause malnutrition, loss of appetite, gastrointestinal pain, loss of energy, and laziness in children. (references 3)
LONGER TERM EFFECTS ON CHILDREN:
4. Significantly decreased school attendance. Studies of Aboriginal children in Malaysia and school children in Kenya both concluded that intestinal worm infections cause >25% increase in school absenteeism. Deworming may improve school participate by allowing sickly and listless children to attend more regularly or concentrate better. (references 4)
5. Significant decreases in future earnings. Intestinal roundworms cause tremendous hardships in terms of future earnings of infected children. This outcome is likely a direct result of decreases in health, growth, cognitive development, and school attendance. Hookworm infections in children in the Southeastern United States circa 1900 resulted in a drop of about 37% in adult wages. Deworming Kenyan children was associated with a 21-29% increase in future earnings. (references 5)
(1) Moore et al., 2001, Intl. J. Epidem. 30:1457-1464.Hall et al., Matern. Child. Nutr., 2008, Suppl 1:118-236.
(2) Sakti et al, Trop. Med. and Intl. Health, 1999, 4:322-334. Grigorenko et al., J. Appl Develop. Psych, 2006, 27: 499-526.
(3) Walson et al, AIDS, 2008, 22:1601-1609. Kirwan, et al., BMC Inf. Dis., 2010, 10:277. Elias et al., Expert Rev. Anti Infect. Ther., 2007, 5:475-484.LaBeaud, et al., PLoSNegl. Trop. Dis., 2009, 3: e442.Crompton et al., (editors) World Health Organization, 2003, Geneva.
(4) Ahmed et al., Parasitology, 2012, 139: 802-808. Miguel and Kremer, Econometrica, 2004, 72: 159-217.
(5) Bleakley, University of Chicago Working Paper 205, 2006. Baird et al., Worms at Work: Long-run impacts of child-health gains, 2011.