Malaria-parasites resistant to treatment and detection have emerged in Ethiopia

Scientists have detected new strains of Plasmodium falciparum parasite in Ethiopia that are both resistant to current treatments and escape detection by common diagnostic tests — a development that could increase cases and deaths from malaria and make eliminating the persistent disease an even greater challenge[1].

Earlier, scientists had found in Uganda, Tanzania and Rwanda strains of the parasite that causes malaria that were resistant to most available antimalarial drugs; and separately, malaria parasites resistant to diagnostic tests had emerged in the Horn of Africa.

Those parasites have been spreading independently of one another, but the new study is the first published report to confirm the prevalence of this type of double-resistant malaria strain, said study author Jeffrey Bailey, an associate professor of translational research and pathology and laboratory medicine at Brown University.

“Now we're essentially seeing the worst-case scenario: parasites with the mutation that make them resistant to treatment have also picked up the chromosomal deletions that make them invisible to the diagnostic tests,” Bailey said. “This means that it will be harder to detect people who are infected, and then when infected people are treated with antimalarial drugs, that may not work to stop them from spreading the disease.”

The first-line malaria treatment recommended by the World Health Organization is a combination therapy involving artemisinin-based drug compounds, which tend to be very effective in preventing death and reducing transmission. The mutations now detected in Africa provide resistance to artemisinin.

They found that 8.2% of drug-resistant parasites also carried the deletions of the protein-expressing gene (the candidate artemisinin partial-resistance kelch13 622I mutation) that made them undetectable by the diagnostic tests[2].

While in Ethiopia the overall incidence of malaria is low, the disease remains endemic in 75% of the country, with 65% of the population at risk. More than 5 million episodes of malaria occur each year.

“The spread of these parasites will certainly make eliminating malaria in Ethiopia and elsewhere in Africa more difficult and will likely lead to increased cases and deaths,” Bailey said.

[1] Fola et al: Plasmodium falciparum resistant to artemisinin and diagnostics have emerged in Ethiopia in Nature Biology – 2023. See here.
[2] Fola et al: Clonal spread of Plasmodium falciparum candidate artemisinin partial resistance Kelch13 622I mutation and co-occurrence with pfhrp2/3 deletions in Ethiopia in MedRχiv - 2023