Emergence of new mosquito species, coupled with the viruses' resistance to drugs, has researchers worried
The search for a lasting solution to the malaria menace has run into headwinds with the discovery of new malaria-causing mosquito species.
This is compounded by cost of treatment across Africa, which has become very expensive.
Things are not going to be easy, experts say, thanks to increased environmental pollution and a growing drug resistance, which threaten to undo the gains made in fighting its spread.
Prof Benson Estambale, the director of the Institute of Tropical and Infectious Diseases at the University of Nairobi (UNITID), said the number of malaria-causing species of mosquitoes resistant to current drugs in the market is on the rise across Africa.
Out of every 100 Kenyans, 40 are unlikely to respond to the available malaria treatment because they have developed resistance to the drugs.
Malaria, a parasitic disease found within the tropics, mostly warm climatic conditions that support its reproduction, has developed more dangerous strains and survival instincts, making its cure expensive and beyond the reach of many.
A new line of treatment based on an artemecin derivative and the coartem cocktails, which are now being recommended, is proving to be too expensive with the prices ranging from Sh400 to Sh600 a dose.
"How are people going to access these drugs?" posed Estambale. "Resistance to malaria drugs is a big problem. The resistance started with chloroquine in the Far East, spreading through Africa. The malaria parasite has enzymes which adopt to the drugs used to treat the infection."
Scientists are now vouching for the return of old malaria treatment methods to counter renewed drug resistance and the resurgence of the disease partly due to change of climate, which has created an enabling environment for their survival.
The parasite in the mosquito was discovered to degrade the active chemicals in the chloroquine, rendering the drug useless and forcing scientists to look for new methods and new combinations of drugs to manage the leading killer disease in developing countries.
Scientists say the high level of drug resistance is worrying given that most of the drugs developed to tackle the disease are rendered useless faster than scientists are able to develop a new combination. "The insurgence of malaria is due to the breakdown in the provision of health services," said Estambale.
Doctors working in Nairobi say the level of drug resistance has been fuelled by carelessness in drug use.
"It is a global trend because resistance to drugs has developed over the last 20 to 30 years," concurred Dr Ndwiga Njue Mwachandi, a Nairobi-based consultant paediatrician.
He explained: "Our first mode of treatment was the quinine, then we moved to chloroquine but resistance to these drugs developed very fast and we shifted to using a combination of drugs known as chamoquine, which is made up of fansidar and metakelfin, but these have also been knocked down by the resistant strains."
The complex nature of the mosquito parasite is seen in its very complex development and survival tactics, especially the malaria-causing type, the female anopheles mosquito. Scientists have counted up to 60 different types of mosquito species and innumerable sub-species in Africa.
"There are quite a number of mosquitoes, the most complex one is the anopheles Gambie; it has six sub-species and is the most efficient. It is strictly a human-biting species and usually bites people in the house," said Estambale.
He said the species has the potential to cause severe bleeding and can also spread deadly tropical diseases such as the dreaded Ebola and Marburg viruses, which killed 300 people in Angola.
"Mosquitoes cannot cause haemolysis - bleeding from all orifices after a major internal bleeding - but they can carry agents or diseases which cause haemorregic fevers," Estambale said in an interview at his Kenyatta National Hospital office.
"The malaria causing parasite became resistant to these due to the misuse of the drugs. People take a dose to suppress the germs, once the level goes down, they stop using it, this makes the mosquito parasite to develop resistance," Dr Mwachandi elaborated.
The high rate of drug resistance, a result of over-the-counter treatment methods that focus on suppressing the plasmodium, the germ that causes the killer disease, is to blame for the increasing drug resistance, he said.
"With time, you have an enemy and you need multiple doses to reduce its load but since the parasite has been used to being kept dizzy, even the new treatment mode finds it too resistant because the germ develops techniques to overcome the medicine," he said.
Medicines developed to attack the parasite are specifically modelled to fight a particular strain, which makes its elimination nearly impossible, the researchers say.
But Mwachandi explained the current combination of drugs mainly grouped under the name Coartem - a combination of lumefantiae and artemesisaia - as being very effective in fighting the parasite.
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"These drugs can interfere with the vital enzymes making it impossible for the parasite to survive. Some of these drugs, which combat malaria, prevent the organism from surviving," he reiterated.
The complex treatment process, which involves a combination of expensive drugs, scientists fear, may render the control of malaria impossible due to the high poverty levels across the country.
