Research presented at the annual American Society of Tropical Medicine and Hygiene meeting suggests that malaria-infected children can become superspreaders by infecting mosquitoes with the disease. Moreover, children spreading infection are found to be asymptomatic.
Malaria is typically spread during the rainy seasons twice a year from three species of mosquitoes. Young asymptomatic children can now be added to ways the disease is spread. Researchers have yet to determine if human to mosquito transmission results makes malaria more infectious or not.
When asymptomatic children spread malaria to mosquitoes, the infected mosquitoes can go on to infect other people in the region. The research was conducted on children in Tororo, Uganda, where the team discovered that children between five and 15 years old were the main cause of malaria-infected mosquitoes.
Fortunately, reported Chiara Andolina from Radboud University, the region they studied has efforts to control the spread of malaria. Without these efforts, the young asymptomatic children have the potential to trigger a malaria epidemic.
According to the Severe Malaria Observatory, Uganda has the third-highest cases of malaria in the world. In 2017 and 2018, efforts to prevent malaria resulted in reducing cases by 1.5 million or 11%.
Investing heavily in malaria control naturally reduces the malaria burden, said Bousema. "But to completely eliminate malaria, scientists have to find and purge any remaining hideouts of the parasite."
531 adults and children were monitored for malaria for two years. Every month, malaria screenings were conducted and blood samples were assessed.
After experiments in the laboratory where mosquitoes were given infected blood samples, results showed that over 60% of infections were traced back to four asymptomatic children. Two of the infected children were below five years old.
Altogether, there were 148 cases of malaria with 110 asymptomatic cases. Afterward, blood samples were given to mosquitoes and were transferred in a container where they could collect blood from a skin-like membrane. After dissection, the mosquitoes were assessed for how they got infected. 99.04% of infections were from asymptomatic blood samples.
While symptomatic patients have access to a clinic and can receive treatment before transmitting the disease to mosquitoes the challenge now is how to detect asymptomatic people with malaria.
Teun Bousema said, "asymptomatic infections really dominated in children .. and schoolchildren somehow have longer duration infections." Avoiding the resurgence of malaria in the region should mean a specific focus on school-age children.
For instance, frequent malaria screenings and treatment should be available in schools to significantly reduce the outbreak of the disease. Mosquito nets are also typically used by pregnant women and children below the age of five. There need to be more preventive measures for school-aged children, said the authors, so they will avoid getting infected and potentially infecting others through human-to-mosquito transmissions.
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