Challenge #1: Find the parasite
You can't beat an opponent you can't see
Malaria thrives on misinformation. It always has. Even the word malaria is a misnomer. It’s Italian for “bad air,” because the Romans attributed the seasonal sickness (that killed at least four Popes, and probably the poet Dante) to noxious fumes coming off the swamps. It wasn’t until 1897 that Dr. Ronald Ross confirmed the mosquito as the vector that spreads the disease.
And misinformation is one of the big reasons malaria continues to kill a child at the rate of one every sixty seconds. Solving the information challenge is going to be key if we’re going to end this disease, and no piece of information is more vital than knowing who is carrying the parasite and who isn’t.
THE HIDDEN MALARIA CHALLENGE
While there are more than 200 million malaria cases every year – that is, people who are getting sick from the disease – it is estimated that there are five times as many people carrying the parasite in their bodies at any given moment – a ticking time bomb of illness and infection.
That amounts to more than one billion people – one out of every seven people on the planet – who are potentially infected with the malaria parasite, jeopardizing their health, hampering their productivity and making them a source of infection for their families and communities. And, most of them have no idea they’re carrying the potentially deadly disease!
The biggest host of the malaria parasite is healthy people, not sick people or mosquitoes.
The insight that sick patients showing up at clinics are only the tip of the malaria iceberg underpins emerging strategies for eradicating the disease. Simply put: you can’t beat malaria if you can’t find it. So any attempt to eradicate the disease must start with developing the diagnostic capabilities to find and free the roughly one billion people living with the parasite in their body and stop them from transmitting.
It may sound like a daunting task, until you consider how far we’ve come in recent years – and how fast.
THE DIAGNOSTIC REVOLUTION
Until 2010, there was no practical way to get a timely, accurate diagnosis for malaria. If you had a fever and wanted to be tested for malaria, you had to travel a long distance – sometimes tens of miles on foot – to find a hospital or clinic equipped with an expensive microscope and a trained lab technician. You had to take a blood slide, then wait several hours for the result – hoping that the lab technician read it right.
It was impractical, and people simply didn’t do it.
In many African languages, the words for “malaria” and “fever” are the same. It’s easy to understand why. Absent practical diagnostics, doctors simply treated every fever as if it was malaria and hoped for the best.
Then came the breakthrough: the rapid diagnostic test, or RDT. This simple, fifty-cent, finger-prick blood test can tell you in a matter of minutes with better than 99% accuracy if your fever is malaria.
The RDT has revolutionized the malaria fight, enabling lightly trained community health workers operating on the far reaches of the health system to test patients for malaria. Negative results are as important as positive ones as they direct doctors to consider other top killers, such as pneumonia and upper-respiratory infection. There are now more than 200 million RDTs distributed across Africa each year.
NEXT GENERATION TESTS
Today, we need to revolutionize diagnosis yet again, this time with a focus on identifying asymptomatic cases and guiding treatment.
Current RDTs have a sensitivity of 200 parasites per microliter of blood – sufficient for identifying all cases in sick people. But finding low-levels of the parasite in asymptomatic patients is like an elaborate game of hide and seek. To do it, we need a new generation of simple, portable, inexpensive diagnostic tests that are 10 times more sensitive, detecting malaria at levels of 20 parasites per microliter or even lower.
Fortunately, through innovative public–private partnerships led by groups like the Medicines for Malaria Venture (MMV) and Seattle-based partner PATH, we’re well on our way to developing next-generation diagnostic tests.
Other next-generation diagnostics will potentially help solve some of the treatment challenges that stand in the way of elimination. Efforts to tackle the dominant strain of malaria in Asia and South America, known as P. vivax, have been hamstrung by the fact that some people have an adverse reaction to the drug recommended for completely clearing the parasite, due to a common inherited trait known as G6PD enzyme deficiency.
The development of diagnostics to identify individuals with G6PD deficiency would ensure better use of current drugs and potential new single-dose treatments, such as tafenoquine, currently in development by GlaxoSmithKline and MMV.
Armed with new diagnostics, we’ll be in a position to take the fight to the parasite. Instead of passively waiting for sick people to show up at clinics, we can go on offense: actively testing and treating entire communities to find and root out malaria, while ensuring the type of treatment provided to patients will be safe and effective.
Which sets up the next of our challenges - check back in next week to read about another big innovation in the malaria fight: developing a complete cure!