In vivax and Ovale malaria, Relapses are due to
**Core Concept**
Malaria relapses occur due to the persistence of the parasite within the host's liver cells, particularly in the case of *Plasmodium vivax* and *Plasmodium ovale*. These parasites can remain dormant in the liver for extended periods, leading to recurrent infections.
**Why the Correct Answer is Right**
The correct answer is due to the phenomenon of hypnozoites, a dormant stage of the parasite that can be found in the liver cells of individuals infected with *P. vivax* and *P. ovale*. Hypnozoites are responsible for the relapses of malaria, as they can reactivate and initiate a new infection cycle. This is in contrast to other malaria parasites, such as *P. falciparum* and *P. malariae*, which do not have a dormant liver stage and therefore do not cause relapses.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not specify the dormant liver stage of the parasite responsible for relapses.
* **Option B:** This option is incorrect as it does not accurately describe the mechanism of relapses in vivax and ovale malaria.
* **Option D:** This option is incorrect as it is a general statement about malaria transmission and does not specifically address the mechanism of relapses.
**Clinical Pearl / High-Yield Fact**
It's essential to note that chloroquine and primaquine are often used to treat *P. vivax* and *P. ovale* malaria, with primaquine specifically targeting the hypnozoite stage to prevent relapses.
**Correct Answer: C. Hypnozoites**