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Malaria is a life-threatening disease caused by a parasite transmitted by infected mosquitoes. According to the World Health Organization, almost 50 percent of the world’s population is at risk of contracting the disease. Thus, a team of researchers decided to use blue dye as a weapon against malaria.
About 212 million cases of malaria and approximately 429,000 malaria deaths have been reported in 2015. Current prevention and control measures reduced malaria death rates by 29 percent in the world since 2010. But, the countries in Sub-Saharan Africa still have a high prevalence of malaria, making the region the home of 90 percent malaria cases and 92 percent malaria deaths.
In the continuous effort to eradicate malaria, a team of researchers from various institutions teamed up for a randomized, controlled trial. The trial involved the application of blue dye or methylene blue. Methylene blue as malaria treatment is not unworldly because it was used before in the late 1800s. In fact, it is the oldest synthetic medication for the disease.
But aside from being an anti-malarial drug, methylene blue is also used as a lab stain and a treatment of methemoglobinemia, a blood disorder that happens when a little amount of oxygen is delivered to the cells. The blue-colored chemical acts an antidote by reducing the overwhelming amount of methemoglobin in the blood.
In the new study, the researchers added the blue dye to dihydroartemisinin-piperaquine, a drug used to treat malaria, and discovered that the dye killed the parasites which cause the disease in just two days. The discovery has a strong impact on preventing mosquitoes from spreading the parasites after a person has been bitten. They confirmed this after analyzing another group that only received malaria treatment, but without methylene blue.
Current treatments can cure the people with malaria; however, it does not stop the spread of the parasites because recovering patients still carry gametocytes, the stage of the parasite wherein it can be passed from humans to mosquitoes. The mosquitoes carrying the gametocytes can inject it to healthy people, where the parasite will mature and start a new series of outbreaks.
Malaria typically develops within 10 days to 4 weeks after contracting the infection. But the symptoms may not develop for several months as the parasites lay dormant. Clinical symptoms of malaria include fever, chills, sweats, headaches, nausea and vomiting, and body aches. In territories where the disease is prevalent, the physical symptoms include elevated temperature, weakness, mild jaundice, liver and spleen enlargement, and increased respiratory rate.
Left untreated, malaria can lead to serious health complications, such as severe anemias due to the destruction of red blood cells, acute respiratory distress syndrome as an inflammatory reaction of the lungs, acute kidney failure, low blood pressure, metabolic acidosis from excessive acidity in the blood and tissue fluids, and cerebral malaria in which the parasites attack the brain, causing abnormal behavior, seizures, and coma.
Among five species of Plasmodium, the genus of the malarial parasite, the P. falciparum is the deadliest, causing almost 50 percent of all malaria cases. People infected by this species contract the most dangerous malaria form – the falciparum malaria. In falciparum malaria, the infected red blood cells tend to sludge and clog blood vessels after bursting, which leads to microinfarctions in the capillaries of organs and glands, such as the lungs, the brain, the liver, the intestines, and the kidneys.
While the return of methylene dye is promising in treating malaria, experts are concerned if people can endure its disadvantage.
"The treatment being followed by an intense blue coloring of the urine, and the feces becoming blue on exposure to light, it is not very likely that methylene blue will be much used outside of hospitals," noted in the 1892 publication of the Proceedings of the American Pharmaceutical Association.
"The knee-jerk reaction is, 'My body's full of this chemical.’ It looks worse than it is,” said Ingrid Chen, one of the lead authors of the study and an assistant professor of epidemiology and biostatistics at the University of California San Francisco.
The methylene dye addition to current anti-malaria medications can be a potential solution to many countries, such as Mali, where cases remain high regardless of the current preventive and control measures. According to Prof. Williams Moss at Johns Hopkins Malaria Research Institute who was not a part of the study, both methylene blue and primaquine can be effective in certain places with low malaria transmission to help eliminate the disease. The only challenge the researchers see that can stop the use of the blue dye is the refusal of the public.
According to the Centers for Disease Control and Prevention, the disease killed about 445,000 people in 2016. It also has an estimated 1,700 cases in the United States every year.
[메디컬리포트=Ralph Chen 기자]