P. vivax malaria explained
What is malaria?
Malaria is a serious mosquito-borne infectious disease that occurs in most tropical and sub-tropical areas of the world. The disease is caused by parasites of the Plasmodium group.
In humans, six main mosquito parasite species cause malaria: P. falciparum, P. vivax, P. ovale curtisi, P. ovale wallikeri, P. malariae and P. knowlesi. Plasmodium parasites are transmitted to humans by the bite of female Anopheles mosquitoes.
P. vivax malaria
The challenging biology and ecology of P. vivax cause it to be a major barrier to malaria elimination.
- The complex lifecycle of P. vivax includes an undetectable dormant liver stage form, called the hypnozoite which may reactivate, causing multiple episodes of illness (relapses) from a single infectious bite, thus increasing the burden of disease. In some settings, up to 75-80% of vivax cases presenting for treatment may be due to relapse.1
- Hypnozoites represent a silent transmission reservoir, allowing the parasite to go undetected by conventional malaria control measures.
- Transmission from humans to mosquitoes may occur before the presence of malaria symptoms, further complicating detection.
- The disease is transmitted by a diversity of mosquito vectors adapted to a wide range of habitats; many mosquitoes bite during the day and rest outdoors, presenting challenges for vector control efforts.