Steve Dada
18 March 2009
Lagos — Scientists may have recorded another milestone over malaria eradication, by the discovery of what triggers an immune response to the development of a parasite in several mosquito varieties that cause malaria in humans.
This was the result of a study by Johns Hopkins University Research Institute released to the public yesterday.
Malaria kills more than one million people worldwide every year.
By silencing the gene, the scientists found they could stop the formation of the parasite in the gut of the mosquitoes, George Dimopoulos, PhD, the senior author of the study and associate professor at the Institute, said in a press release.
The parasite that causes malaria in humans is called Plasmodium falciparum. It affects three varieties of mosquitoes found in Africa, the Americas and Asia.
"When a mosquito is feeding on malaria-infected blood, the parasite will be recognized by the mosquito's immune system through receptors that then start the immune response. In the wild, this response is believed to occur too late to mount an efficient immune defence that would kill all parasites. At least a few Plasmodia will successfully develop inside the mosquito and enable transmission of malaria," Dimopoulos said.
"In the lab, we activated this immune response in advance of infection, giving the mosquito a head start in defeating the invading parasite," he added.
The findings by Dimopoulos and his colleagues Lindsey Graver and Yuemei Dong was published March 13.
The disease, a recurring phenomenon, has done greater havoc to humanity occurring in about 100 countries, largely in the tropics, with half of the figure affecting Africans.
The efforts at global eradication of the hydra-headed disease started in 1600 when the first treatment emerged in Peru, where native Indians cure malaria with Cinchona bark and becoming available 50 years later in England with the name Jesuit Powder.
In 1969, global malaria eradication programme stopped shortly after most countries in Europe such as Hungary, Romania, Yugoslavia, Spain, Italy, Poland, Netherlands and Portugal had succeeded in eradicating the disease, leaving Africa essentially as non-beneficiary of the eradication efforts.
In 17th century, Africa was named 'White Man's grave which perhaps could best be described as the 'black man's grave today due to the damage done to human's health by the disease from which 300-500 million attack cases are reported annually killing about 1.5 to three million people, with 85 per cent coming from Africa, accounting for five per cent of global fatalities with children less than five years and pregnant women being worse hit.
One child, according to report, dies of malaria every second in Africa, while every 12 seconds someone somewhere dies of the disease in the world, in which Plasmodium falciparum accounts for 98 per cent of all cases in Nigeria causing high morbidity and mortality.
Malaria accounts for 60 per cent of Out Patient Department (OPD) visits and accounts for 30 per cent of under-five mortality, 11 per cent of maternal mortality, while children experience one to four malaria attacks annually.
In Nigeria, according to report, rural dwellers suffer more than city dwellers in which 300,000 children die annually causing chronic anaemia in children, poor development and disability.
Experts said prompt recognition and appropriate management of uncomplicated falciparum malaria is of vital importance as patient with the condition might present, with confusion, or drowsiness with extreme weakness.
In addition, a number of complications may develop which include: acute pulmonary oedema and adult respiratory distress syndrome (ARDS), circulatory collapse, shock, septicaemia, abnormal bleeding, jaundice, haemoglobinuria, high fever and hyperparasitaemia.
http://allafrica.com/stories/200903180569.html