Malaria has been with me since the late 1980′s after 6 years in Malawi.
During the 90′s I had it twice per year in Feb and Sept. Blood tests always came up negative. Treatment was with Chloroquine, later Halafantrin and then Co Artem. 2 or 3 treatments were required as symptoms appeared 2 weeks after completion of initial treatment.
In 2004 I treated with a bodyweight specific dose of Arinate and did not have another bout until 1 week into a Southern Mozambique visit in Aug 2008. (I was on doxycycline as a prophylactic but discontinued due to it causing diarrhoea.) Treatment was with Artecospe (unsuccessful) and CoArtem (successful.) In Nov 2010 after a visit to N Botswana another bout – treated twice with CoArtem.
Sept 18 2011 it struck again. (I have not been near a malaria area since Nov 2010). CoArtem unsuccessful 3 times with Artecospe have not worked and now on Co Arinate.
Have I some resistant strain of Malaria? Does eating during a malaria bout reduce the efficacy of treatment?
So far, no strains of malaria have been discovered to be resistant to Coartem. Moreover, recurrent malaria is only caused by Plasmodium vivax and Plasmodium ovale—neither of these are nearly as common in Malawi as Plasmodium falciparum, which can recrudesce (parasites re-appear in the blood) if not treated appropriately but will not relapse or reoccur months or years after the initial infection—if you have tested positive for malaria in your more recent bouts of illness, you should ask your doctor whether it could be P. vivax or P. ovale.
If it is one of these two species of malaria, you should ask about the possibility of taking primaquine to kill the dormant liver stages of the parasites and prevent future recurrence. You will need to be tested for G6DP prior to being able to take primaquine.
However, since you tested negative in Malawi initially, I suspect you did not have malaria at all at that point, and should have been tested further to determine what was causing your symptoms. Moreover, chloroquine should not have been the first treatment of choice, as resistance is rife in sub-Saharan Africa.
The symptoms of malaria are notoriously non-specific and therefore diagnosis is crucial prior to treatment, as many other infections will present with similar clinical symptoms, such as fever and nausea. Therefore, if you have any further symptoms which you suspect might be malaria, please visit a doctor or travel medicine clinic straight away for a blood test. If it is not malaria, there is no point taking further doses of Coartem or other anti-malarials and further tests might reveal another diagnosis.