I am arriving Nairobi 11th July and after staying in a hotel there for 3 days doing a 5 day safari in Masai. After that flying down to Mombasa till Aug 3rd for the rest of my holiday. Last time I came to Kenya I took Malarone as I was in Mombasa but seeing it is July and I will be in Nairobi to start, is it necessary to be taking Malarone there? It will be expensive to buy (in Oz) for 4 weeks supply. I have read that Nairobi is not mosquito infected.Would repellant be enough?