Plasmodium vivax is a protozoan parasite transmitted to humans through the bite of infected mosquitoes, and is the cause of one of the most common forms of malaria. Although it is not one of the most dangerous forms, it affects many people annually and can be somewhat resistant to the drugs typically used to treat malaria. Once contracted, it can remain in the liver for years if not treated with the right medications. Since the condition often occurs in the poorest parts of the world, these medications are not always available, and some people continue to suffer from the effects of plasmodium vivax for years. These infections affect poor countries in other ways because many hospitalizations are due to the initial symptoms of malaria, which is costly.
Areas where people can get Plasmodium vivax include Asia, the Middle East, islands like Australia, New Guinea, and others (Oceania), Central and South America, and limited parts of Africa. There are occasional reported cases of p. vivax malaria elsewhere, such as North America, but most cases occur in the areas mentioned above. People traveling to places known for a high load of plasmodium vivax or other malaria infections should consult a doctor.
When people are affected by plasmodium vivax, they often show symptoms of high fever, chills, fatigue, and profuse sweating. These symptoms often last for a period of about two to three days, but can be complicated if a person has additional illnesses. Other symptoms such as vomiting, muscle aches, dizziness, or fever that come and go in some people. After this primary infection, the disease can become inactive, but symptoms can recur regularly and other conditions such as jaundice can develop because plasmodium vivax establishes itself in the liver.
In most cases, people can have a recurrence of the disease without treatment, but do not develop life-threatening complications. Others may have a complicated disease and conditions such as liver failure. The five different types of malaria can be diagnosed with small blood samples, which can help identify the causative parasite and determine the most effective treatment.
The normal treatment for plasmodium vivax is a 14-day cycle of the drugs chloroquine and primaquine. In areas where P. vivax is profuse, strains of the parasite are resistant to chloroquine and other drugs are used instead. With this treatment, the disease can be completely cured, either in the early or later stages. Other blood tests check for the additional presence of the parasite, but once it is no longer evident after a course of treatment, the disease is considered completely cured, although some people are reinfected.
There is no vaccine against plasmodium vivax, although people traveling to areas with a high incidence of malaria can use chloroquine prophylactically. Countries also promote prevention with mosquito reduction programs, and these can help reduce the risk of contracting the disease. Still, many physicians advocate for faster work on vaccine development for all forms of malaria.