The lead article in MalariaWorld this week is ‘Rapid diagnostics test can detect asymptomatic malaria cases’ by Patel and Duncan of Imperial College, London. The article claims that the new test called Dragonfly is so sensitive it can detect 95% of cases where the numbers of parasites were too low to be detected by looking at blood under a microscope. It is well accepted that microscopy by an expert technician is the ‘gold standard’ for malaria plasmodium detection. However, this article says that PCR testing is the gold standard!
Kary Mullis, the discoverer of PCR (Polymerase chain reaction) said: “Anyone can test positive for practically anything with a PCR test, if you run it long enough with PCR if you do it well, you can find almost anything in anybody. It doesn’t tell you that you’re sick.” We all remember how PCR tests run for very long cycles detected many COVID-19 cases during the pandemic. Clearly PCR and Dragonfly are supposedly detecting plasmodia that are not detectable by the gold standard, microscopy.
The article title claims that asymptomatic cases (i.e. people who are not ill) can be detected. Presumable they can then be put on a dose of artesunate or another treatment generating more revenue. The benefit of detecting asymptomatic cases is supposed to be that by treating asymptomatic cases before they have symptoms, there will be less opportunity for a mosquito to become infected by biting them. However, if plasmodia levels are so low they can only be detected with super-sensitive methods, it seems unlikely a mosquito sucking a tiny aliquot of blood will be infected by such a person, even if the mosquito transmission hypothesis were true.
The other benefit of Dragonfly is that it will be even cheaper to run tests on many people even those without symptoms. Dr Jesus Rodriguez-Manzano of the Department of Infectious Disease stated “The technology delivered through this work represents a game changer for malaria control efforts.” If malaria were indeed a parasitic illness caused by plasmodia being spread by mosquito bites, this might be true. However, the evidence supporting this hypothesis is very flimsy. Seeking the truth is very difficult for researchers such as Rodriguez-Manzano. To again quote Upton Sinclair, ‘It is difficult to get a man to understand something when his salary depends upon his not understanding it.’