Plasmodium vivax
Plasmodium vivax is a protozoal parasite and a human pathogen. This parasite is the most frequent and widely distributed cause of recurring (Benign tertian) malaria, "P. vivax" is one of the five species of malaria parasites that commonly infect humans. Although it is less virulent than "Plasmodium falciparum", the deadliest of the five human malaria parasites, "P. vivax" malaria infections can lead to severe disease and death, often due to splenomegaly (a pathologically enlarged spleen). "P. vivax" is carried by the female "Anopheles" mosquito; the males do not bite.
Soil-transmitted helminthiasis
It has become the most common parasitic disease of humans worldwide. Approximately two billion people (about a third of global population) are infected as of the latest estimate, and four billion at risk, surpassing even the all-time most prevalent parasitic disease, malaria. The largest numbers of cases occur in impoverished rural areas of Sub-Saharan Africa, Latin America, Southeast Asia, and China. Its main cause, like for many types of helminth infections, is lack of sanitation, such as the practice of open defecation and lack of hygiene such as hand washing. It is regarded as one of the world's most important causes of intellectual and physical retardation.