Malaria parasites in Kenya can grow drug resistant

Scientists have discovered genetic factors that could enable malaria parasites found in Kenya develop resistance to anti-malaria drugs. 

The discovery means if new forms of treatment are not developed, the progress made against malaria may be at risk.

The study was carried out in Kisumu and other regions in 15 African countries. The results were published last week in the Science journal.

“This is crucial information for understanding how resistance to malaria drugs is developing in Africa," said Prof Abdoulaye Djimde of the the Wellcome Sanger Institute.

He said the information will help track the emergence and spread of drug-resistant strains, assisting efforts to eliminate malaria.

It is the first ever study to uncover the genetic features of the malaria parasites, the Plasmodium falciparum, that inhabit different regions of Africa, including the genetic factors that confer resistance to anti-malarial drugs.

The study was carried out by a network of African scientists, called the Plasmodium Diversity Network Africa.

"The worldwide decline in malaria prevalence is now stalling and additional knowledge, new tools, and intervention strategies will be needed for global malaria elimination and eradication," the scientists say in the study.

No resistance to the current artemisinin-based drugs has been reported in Kenya, although some mosquito populations mostly in Western Kenya have developed resistance to the DDT and pyrethrin pesticides used to treat bednets.

 Malaria prevalence in Kenya has been falling but last year, the country recorded  10.7 million malaria cases, up from 7.9 million in 2017.

Nationally, the prevalence is about eight per cent but hovers around 27 per cent around Lake Victoria, according the 2015 Kenya Malaria Indicator Survey.

The Science study found that Kisumu has the most complex infections of the malaria parasite in Africa, signifying the need for better interventions.

Kenya Medical Research Institute scientist Edwin Kamau took part in analyzing the parasites around Kisumu. 

In general, the study indicated that the of P. falciparum parasites are genetically distinct according to which region of Africa they are found.

However, the results confirmed that populations have shared genetic information over time, particularly genes associated with resistance to antimalarial drugs.

"Genetic material originating from all directions was shared by all populations, indicating that the flow of genes is multi-directional, as opposed to unidirectional from east to west as previously thought. This is crucial information for understanding how resistance to malaria drugs is developing in Africa," said Prof Djimdé. 

Currently, Kenya plans to launch an anti-malaria vaccine targeting at least 120,000 children  in Kakamega, Vihiga, Bungoma, Busia, Kisumu, Homa Bay, Migori and Siaya counties.

The vaccine, RTS,S or Mosquirix, will be given to children aged six months to 24 months in four doses.

The pilot, supported by the World Health Organisation, will assess the feasibility of delivering four doses in real-life settings, and assess the vaccine’s potential to reduce child deaths.

The pilot has faced various delays as it was first scheduled for October last year, then August this year.

The results from the pilot will help Kenya decide whether or not to adopt the vaccine and make it part of routine immunisation.

However, the vaccine – made by GSK - is only effective in 30 to 50 per cent of patients, says the WHO.

Its effectiveness diminishes over time and it disappears fastest in children who are most exposed to malarial mosquito bites. However, because no defence against malaria is perfect, the vaccine is being considered in addition to the existing defences.