Drug-Resistant Mutation of Malaria Detected in Uganda

leading antimalarial treatment no longer effective in 20% of cases

By Jonny Lupsha, Wondrium Staff Writer

Malaria infects 200 million people per year, killing over 400,000. It has been studied for over a century and efforts are constantly made to reduce its mortality rate. A new resistant strain could make things worse.

Close up of blood sample with label "Malaria"
Only the Anopheles species of mosquito carries the parasite called Plasmodia, which is responsible for causing malaria in people who have received bites from infected mosquitos. Photo By Jarun Ontakrai / Shutterstock

Researchers studying blood samples from malaria patients in Africa have confirmed that a new strain of the deadly disease shows resistance to artemesinin, the leading drug used to treat it. Their studies showed that 20% of blood samples contained mutations that rendered the treatment ineffective. It also appears that the strain originated in Uganda as opposed to being carried over from another country.

Malaria has been notoriously difficult to conquer. In his video series An Introduction to Infectious Diseases, Dr. Barry Fox, Clinical Professor of Infectious Disease at the University of Wisconsin School of Medicine and Public Health, described the history of malaria treatment.

Honestly, Do Mosquitoes Serve Any Purpose?

According to Dr. Fox, a British physician in India named Ronald Ross studied malaria beginning in 1894.

“He headed to Bombay Civil Hospital to assess malaria patients and he spent two years studying the disease, and even contracted the illness himself,” Dr. Fox said. “He decided to pay malaria patients to let eight mosquitoes bite them in order to test his theory that mosquitoes were responsible for malaria transmission.

“After the bites, Ross dissected the mosquitoes; he noticed tiny, round cysts that were attached to the mosquitoes’ stomach wall.”

Ross realized that the cysts were actually the malaria parasite. This discovery was such a historic breakthrough that, along with other work he performed, it earned Ross the 1902 Nobel Prize in Medicine. The parasite, known as Plasmodia, is only carried by one species of mosquito: the Anopheles mosquito. Dr. Fox said that the most virulent species of the malaria parasite is Plasmodia falciparum, which is responsible for 50% of malaria infections and 95% of its deaths.

“Each time the parasites are released into the blood, there is a loss of oxygen-carrying red blood cells,” Dr. Fox. “During the blood stage, falciparum has the ability to alter the red blood cells’ surface, causing them to stick to blood vessel walls. This causes a sludging of red blood cells and impairment of oxygen to the brain.”

If untreated, the brain swells and the deprivation of red blood cells cause the heart and lungs to fail.

Treating Malaria

According to Dr. Fox, a treatment for malaria was discovered in Peru in the 1600s by using the bark of the Cinchona tree. Today it is known as quinine.

“In World War II, many battles in the South Pacific, between the U.S. and Japanese armies, were solely for the purpose of securing islands that supported the growth of quinine,” he said. “Later, this ingredient was chemically modified into chloroquine, the first synthetic antimalarial medication.”

All forms of malaria used to be sensitive to chloroquine, but after several decades of treatment, it adapted to the drug and became resistant to it, much as it is to artemesinin now. Dr. Fox said that chloroquine is only still effective in parts of the Caribbean and Latin America. Elsewhere, drugs like mefloquine, malarone, and doxycycline are used.

“Malaria is still prevalent in 106 countries,” he said. “There are ongoing efforts today by the World Health Organization to try to prevent and reduce malaria—for example, by distribution of treated mosquito netting, educational efforts for the native population, aggressive medication treatments, and the spraying of insecticides to reduce the mosquito population—but this is not enough.”

Other solutions suggest killing off mosquitoes entirely and developing malaria vaccinations. One vaccination, Dr. Fox said, resulted in a 50% reduction in malaria in African children. Eradicating mosquitoes and providing vaccinations will likely continue to be the two most important efforts to reduce malaria deaths.

Edited by Angela Shoemaker, Wondrium Daily