QUESTION:

I’m in a malarious country and I had no idea about anti-malarials until I got here, so I started taking anti-malaria(doxycicline) two weeks late. It has been three weeks since I started taking the medicine. Do you think it would work or should I stop taking it?

ANSWER:

It depends a bit on where you are, and what types of malaria are in your region. Plasmodium falciparum usually takes between 7 and 14 days for symptoms to develop after exposure; P. vivax and P. ovale take between 9 and 14 days. P. malariae, on the other hand, sometimes doesn’t show symptoms until 30 days after infection. However, the most acute and dangerous form of malaria is that caused by P. falciparum; as such, if you haven’t had any symptoms since you started taking anti-malarials three weeks ago, you should be ok, and it certainly would be advisable that you continue with the preventative medicine while you remain in the malarial area.

It’s also worth mentioning that because of the lag between infection and symptoms, in many cases you need to continue taking antimalarials for some period of time after you leave the malaria zone. Of course, if at any point you start to develop symptoms, such as fever or chills, go to a hospital or see a doctor for prompt diagnosis.