by JOsé de Souza Nogueira is 63 and says he has had malaria more than 130 times. That’s an exceptionally high number, even for a country like Brazil, where the mosquito-borne disease is endemic. But doctors agree that it’s entirely possible for a small farmer who has spent his entire life in the countryside – the mosquitoes’ favorite breeding ground.
“I work and live alone and sell what I grow: bananas, oranges, sugar cane, cassava… If I have malaria, I can’t take care of the plants,” he says.
In Brazil, tens of thousands of people suffer from malaria every year. The most common form, Plasmodium vivaxis less deadly than malaria typical in Africa, but can be more difficult to combat.
The parasite can lie dormant in the liver before erupting again, causing symptoms including fever, chills, muscle and joint pain, heavy sweating, nausea and vomiting.
Authorities hope that the introduction of a new testing and treatment process, currently in its early stages, will help eradicate the disease from Brazil by 2035.
Since the 1990s, the country has used two drugs to treat P. vivax: Chloroquine for three days and primaquine for at least seven.
However, because chloroquine fights symptoms, many patients stop taking the drug after the first three days when they feel better, so that the parasite in the liver “wakes up” after a few weeks or months.
Patients’ reluctance to continue treatment is understandable, says Eliana Pasini, health secretary of Porto Velho, the capital of the Amazon state of Rondônia, where Nogueiro lives.
“They need to work and want to get back to work quickly,” she says. “Usually they are small farmers, self-employed people, people who come to this region from all over to look for new opportunities.”
But it does cause future costs. “If a patient has a relapse of malaria, you have to give them more medication, they may have to go to hospital,” she says. “That’s why stopping treatment is very bad for us, but also for the patient, who is then bedridden for days.”
So Brazil is trying something new: It is the first malaria-endemic country in the world to use tafenoquine – a drug taken as a single dose – to treat P. vivax cases.
If possible, primaquine is replaced and treatment includes chloroquine for three days and two tablets of tafenoquine on the first day only.
The “new” drug was discovered in 1978 at the US Walter Reed Army Institute of Research, but has been further developed over the last 15 years by GlaxoSmithKline (GSK) and Medicines for Malaria Venture (MMV).
A study conducted in Brazil between 2021 and 2022 – jointly sponsored by the Brazilian and UK governments, MMV, the Bill & Melinda Gates Foundation and Newcrest Mining – found that tafenoquine is a viable option for the country.
However, the new drug is not a panacea. It is not suitable for children, breastfeeding women and people weighing less than 35 kg – and in some of the regions where it is used, there is a high rate of malnutrition.
Additionally, it cannot be used safely without an accompanying test for a genetic condition called G6PD enzyme deficiency, which means both primaquine and tafenoquine can be harmful.
Nogueira is one of the 5% of people who suffer from malaria deficiency. His last bout of malaria was the worst: in early June, he spent five days in hospital in Porto Velho.
“I couldn’t work for days and I felt dizzy. I couldn’t earn any money,” he says. “I was exhausted and had pain in my legs and head.” Doctors diagnosed an increased hemoglobin level, apparently caused by taking primaquine.
At that time, the tests for G6PD enzyme deficiency were not yet available. Only now – along with the launch of tafenoquine – is the Ministry of Health distributing them as a result of another study conducted by the same team. A drop of blood from the fingertip is placed in a portable device that provides results within two minutes.
In order to make the tests available, the British social enterprise MedAccess and the US non-profit organization Path had to give a quantity guarantee to the test manufacturer, the South Korean company SD Biosensor.
Although primaquine can also be harmful to patients with G6PD deficiency – as in Nogueira’s case – if doctors are aware of this, they can change and space out the dosage and increase monitoring to reduce the risk. Tafenoquine is a once-only drug and its dosage cannot be spaced out.
Brazil registered 131,000 cases of malaria (84% caused by P. vivax) in 2022 and is far from its goal of eradicating the disease by 2035. About 99% of malaria cases in Brazil are concentrated in the Amazon states.
Nogueira lives in the Flor do Amazonas settlement in Candeias do Jamari, 25 km from the centre of Porto Velho. Porto Velho has a population of 460,000 but covers an area of 32,000 km², an area larger than Belgium, and parts of it are only accessible by river.
Pasini believes that the geographical location makes the fight against malaria even more difficult.
“Many people live scattered across the vast area, and there is also a population that moves around a lot in search of work,” she says. “Some work in mining, others as small farmers.”
“People start living where no one lived before. They start cutting down trees and come into contact with the mosquito, which infects one person and then another, and a network is created that is difficult to control because these places are not easy to reach quickly due to their difficult accessibility,” she adds.
Since April, the government has trained more than 850 medical workers from five cities on tafenoquine and G6PD testing, stressing that distribution is on schedule, although the drugs and tests had not yet been used on patients as of June 21.
In its first contract, the Brazilian government purchased 15,000 doses of tafenoquine from GSK for £4.30 each, representing less than 15% of the total P. vivax cases in 2022.
According to official information, a further purchase of 103,000 doses is underway and the drug should reach all endemic cities “by the second half of 2026”.
Malaria researcher Marcus Lacerda says the cost of treatment could be an “Achilles heel.” “The drug itself is not expensive, but the test is,” he says.
The government purchased 1,400 devices from SD Biosensor for £210 each and 87,000 test slides for £2.35 each. About 5% of these have been delivered so far, according to the company’s representative in Brazil.
“If someone asks, ‘Brazil has started using tafenoquine. Will other countries do the same?’, I don’t know,” says Lacerda. “Because I don’t know if everyone can afford the G6PD test.”
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This article also mentions the Bill & Melinda Gates Foundation’s support for tafenoquine research. The Guardian’s global development coverage is supported by the Bill & Melinda Gates Foundation through theguardian.org. Read more about how the Guardian ensures its editorial independence here.
