What are the possible ways to diagnose malaria?

Fevers; blood tests. Malaria symptoms show up a week to a few months after being infected by a mosquito bite. Fevers, fatigue, swelling of the spleen, etc... Usually occur. With medical treatment, the symptoms should go away in a couple of weeks. However, without treatment, and depending on the strain of malaria parasite, an infected person can have symptoms for a few years, up to a few decades.