Peter Pedant is on exactly the correct track regarding avoiding mosquito bites. The issue of malaria risk comes up fairly regularly on AB and I have occasionally contributed to the discussion.
I have many, many years experience of living in malarial areas, including some weeks in Madagascar (I envy you of the opportunity, it's a wonderful place), and only for the first three months or so of all that time did I take any medication - I found the medication unhelpful because none of those available provide full cover and in principle I dislike loading my system with chemicals. For much of the subsequent time I had my wife and sons with me, the younger starting at less than two years old - neither I or they took any medication, nor did my mother in law who visited us. None of us got malaria.
If you avoid mosquito bites then you will not get malaria. Follow Peter Pedant's advice on this and additionally use insecticide liberally in your accommodation, keeping all doors and windows shut while you are there. For even better precaution take with you a mosquito net and unfailingly use it over your bed (assuming fitting it is an option) - you could enquire in advance, perhaps they already have nets. The comment that malarial deaths in Europe are very rare is pertinent (dog parasites are estimated to cause blindness in one child per week in the UK but even the NHS plays this down, not to mention the vitriol from dog owners if you point the fact out) but for months after your return you should insist on a blood test for malaria (even if you have to pay for it, it is very swift and simple) if you feel ill - remember that sometimes people with malaria recover briefly before becoming properly ill. Heed this advice even if you take buckets of tablets because you can still get malaria.