Can malaria still be detected after a year?
In most cases, malaria infections are relatively short-lived, lasting only days or maybe a couple of weeks at most, particularly if the patient receives appropriate treatment. In these cases, you would not be able to detect any malaria parasites in the patient’s blood after the infection – so certainly not after a year. However, you could possibly still detect antibodies (proteins that the body produces to combat infections) against malaria – some types of antibodies can last for months or even years. In this way, you could probably detect after a year that a person had been infected with malaria at some point in the past, even though they no longer have an active infection.
In addition, there are some types of malaria, notably caused by Plasmodium vivax, which can persist in the body even after the initial infection is over. By hiding out in the liver, this type of malaria can lie dormant for months or even years, before recurring again. In this way, you could potentially say that someone with P. vivax infection might be able to have their infection detected again after a year, despite not having been sick in the meantime since his or her initial infection. Malaria caused by P. vivax needs special treatment, with a drug called primaquine, to kill the parasite stages that can hide in the liver, and thus prevent further infection.