Here’s a tricky malaria conundrum question we received last week. What do you think? Our answer follows below:
Hello Doctor! Why is it that whenever a mosquito bites me, I’ll be malaria positive – even if I finished taking antimalarials on that day?
Thank you —
First, when you live in a Malaria endemic area like Nigeria, chances are that most people without symptoms who have their blood tested will show evidence of malaria parasite within the blood.
This is because many people are bitten by the mosquito which introduces the parasite when feeding on the blood.
So that’s one reason – you’ve been treated, but bitten again and received a fresh dose of parasites.
But- I can hear you say – how can I have the parasite and feel ok – that is NO symptoms??
The reason is that having symptoms depends on which stage of the parasite’s lifecycle is in your blood – not all stages cause obvious malaria illness.
The parasite Plasmodium
When the mosquito bites me or you, it injects parasites (plasmodium) at a particular stage of growth into the blood.
At this stage, the parasite is called a sporozoite.
These travel in the blood into the liver where they mature into another form – let’s call these schizonts.
When the schizonts are big enough, they burst and form Merozoites.
It is these Merozoites that cause the symptoms – they enter the blood, blood cells, destroy blood cells, multiply – and while all this is going on you will have symptoms – and if tested you will be positive.
Now the antimalarial medication works by killing the malaria parasites during their active development stage in the liver and red blood cells – not when you’ve just been bitten.
(Or the antimalarial may not completely clear all the parasites in the liver and blood cells and any still developing emerge at a later date).
For these reasons – you may have been completely treated of Malaria, but if bitten again, your blood sample will show some parasites in the undeveloped stage which are preparing to enter the liver and mature to the active stage.
What do you think?
Comment below on your experience with mosquito bites, blood tests and malaria treatments!
Editing By AskAwayHealth Team
All AskAwayHealth articles are written by practising Medical Practitioners on a wide range of health care conditions to