Yemen: The World Health Organization estimated that malaria cases rose in 2016 to 433,000 from 336,000 the year before.
January 20th, 2018
The malaria parasite life cycle involves two hosts. During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host 
. Sporozoites infect liver cells 
and mature into schizonts 
, which rupture and release merozoites 
. (Of note, in P. vivax and P. ovale a dormant stage [hypnozoites] can persist in the liver and cause relapses by invading the bloodstream weeks, or even years later.) After this initial replication in the liver (exo-erythrocytic schizogony 
), the parasites undergo asexual multiplication in the erythrocytes (erythrocytic schizogony 
). Merozoites infect red blood cells 
. The ring stage trophozoites mature into schizonts, which rupture releasing merozoites . Some parasites differentiate into sexual erythrocytic stages (gametocytes) 
. Blood stage parasites are responsible for the clinical manifestations of the disease.
The gametocytes, male (microgametocytes) and female (macrogametocytes), are ingested by an Anopheles mosquito during a blood meal 
. The parasites’ multiplication in the mosquito is known as the sporogonic cycle 
. While in the mosquito’s stomach, the microgametes penetrate the macrogametes generating zygotes 
. The zygotes in turn become motile and elongated (ookinetes) 
which invade the midgut wall of the mosquito where they develop into oocysts 
. The oocysts grow, rupture, and release sporozoites 
, which make their way to the mosquito’s salivary glands. Inoculation of the sporozoites into a new human host perpetuates the malaria life cycle.