If untreated how long will a person suffer symptoms caused by Malaria?
The answer to that depends a lot on what type of malaria they have as well as their own immune status, and particularly if they have been infected with malaria before. So, for example, P. falciparum is the most severe and deadly kind of malaria, and without treatment, many people who do not have acquired immunity (from previous infections) are likely to die within just a few days. This is the type of malaria that causes the most deaths, and explains why most of the fatalities occur in young children, who have not had the chance to acquire immunity.
In contrast, other kinds of malaria are less severe, and so symptoms can persist before the malaria parasite is naturally cleared by the parasite, usually within 1-2 weeks. In extreme cases, this can last much longer; Plasmodium malariae is the slowest replicating form of malaria, and so frequently causes mild infections which can last weeks, if not months. In some cases, people are infected with low levels of P. malariae for years without even experiencing symptoms, since their own immune system is able to keep levels of the parasite low enough so that they don’t cause noticeable disease.