Scientists try new tactics in the fight against malaria

After years of a downward trend, malaria deaths have rebounded from 16,000 in 2016 to 17,553 in 2017, according to the Economic Survey of 2018 that was released last week. Malaria also retained its spot as the second leading cause of death in Kenya, after pneumonia.

The mosquito-borne infectious disease continues to be a headache in the quest for its eradication, with a target to end malaria in the next 12 years, even as plasmodium, the malaria parasite, develops resistance to the most effective drugs available.

TREATMENT

Researchers acknowledge that new treatments and mechanisms to fight the disease are needed more urgently than ever, and they are using genetic and chemical tools targeting plasmodium at various stages of development in mosquitoes and humans.

Efforts include finding new ways of taming the anopheles mosquitoes that carry malaria parasites, and that keep evolving to outwit current methods of stopping the disease in its tracks.

Already, new drugs and vaccines are being tested on patients for effectiveness in fighting malaria including drug-resistant strains.

Among them are two new drugs under trial: KAF 156 and ivermectin, an old drug discovered in the 1980s and used to kill parasitic worms responsible for river blindness and elephantiasis.

A clinical trial in Kisumu suggests that unlike existing drugs that target the parasite to reduce the spread of malaria, ivermectin can be used to kill mosquitoes.

“Already, we have found that one tablet of ivermectin can kill mosquitoes for up to seven days. If we increase the dosage to one-and-a-half tablets or three, the drug’s killing effect goes up to 28 days,” says Dr Simon Kariuki, chief research officer at the Kenya Medical Research Institute’s Centre for Global Health Research in Kisumu.

In a study published in the Lancet Infectious Diseases last month, researchers gave 47 participants three tablets (600 milligrammes) of ivermectin for three consecutive days and then took blood samples that were then fed to mosquitoes in cages.

RESEARCH

The team, working in partnership with the US Centers for Disease Control and Prevention (CDC), and other colleagues from around the world, found that the blood of patients who took three high doses of ivermectin in pill form, kills the insects instantly and remains poisonous  to mosquitoes for up to 28 days.

“If validated in larger scale trials, Ivermectin not only has the potential to play a role in malaria elimination efforts, but will also help address the current challenges of targeting mosquitoes that are resistant to standard insecticides,” notes Dr Yeri Kombe, the director of Kenya Medical Research Institute (Kemri).

Also in Kisumu County are trials of a new anti-malarial drug developed by Swiss pharmaceutical company Novartis, alongside Medicines for Malaria Venture (MMV). The medicine known as KAF156 targets drug-resistant malaria and will be trialled in eight other countries in Africa and Asia.

According to Dr Bernhards Ogutu, a chief research officer at Kemri, initial tests suggest that KAF156 has the potential to rapidly clear malaria infection, including resistant strains, as well as block transmission of the mosquito-borne parasite.

“The drug is already showing unique characteristics and has displayed effectiveness in some drug-resistant parasites,” said Dr Ogutu, when HealthyNation visited one of the trial sites in Siaya.

KAF156 belongs to a new class of anti-malarial compounds called imidazolopiperazines. The drug is designed to be used in combination with an improved formulation of the existing anti-malarial drug lumefantrine.

Researchers are also working towards finding new ways of improving the insecticides used in bed nets as well as indoor spraying of homes, as mosquitoes become more resistant to commonly used insecticides. Field trials of the new malaria vaccine known as RTS,S or Mosquirix will also be launched later this year.

However, science alone cannot be used as a silver bullet in the fight against malaria.

“We need political goodwill to empower people with stronger health systems and human resource capacity as well as basic knowledge about prevention,” says Dr Kariuki.