Malaria relapses months after primary infection are associated with exoerythrocytic liver stages in infections with which Plasmodium species?

• A. P. falciparum
• B. P. malariae
• C. P. ovale
• D. P. cynomolgi

Answer: (C)

Dormant liver forms called hypnozoites allow malaria parasites to hide in the liver and reactivate months after the initial illness, causing relapse. This behavior is classically seen with species that infect humans and form these hepatic dormant stages. Among the options, the one known for liver hypnozoites and late relapse is P. ovale. The other choices don’t produce relapse through dormant hepatic stages: P. falciparum and P. malariae relapse, if they occur, are due to blood-stage dynamics rather than latent liver forms. P. cynomolgi is a simian malaria that can share the hepatic dormancy trait, but it’s not a primary human pathogen in typical clinical contexts.