Anti-plasmodial Property Of Moringa Oleifera Seed Extract On Swiss Mice

CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 Definition and History of Malaria
The term malaria was derived from the Italian ‘mala aria’’ meaning foul air (Service and Townson, 2002). It is a protozoal blood infection caused by mosquito-borne apicomplexan parasites of the genus Plasmodium, which are transmitted from one human to another via the bite of infected female Anopheline mosquito species (Carter and Mendis, 2002; Greenwood et al., 2005). United States National Institute of Allergy and Infectious Diseases (U.S. NIAID) defined malaria as: a disease caused by a parasite that lives part of its life in humans and part in mosquitoes (NIAID, 2007).
Malaria is an ancient disease that could be traced back to the very earliest human history. It was accepted as a disease by Hippocrates in the 4th century BC (Krettli and Miller, 2001). In the early 17th Century, the Peruvian bark of Cinchona tree was known to treat fever (CDC, 2016). In 1847, Heinrich Meckel identified black-brown pigment granules in the blood and spleen of insane person (David, 2006). Othmer Zeidler synthesized Dichloro-Diphenyl-Trichloroethane (DDT) in 1874 for his thesis. Alphonse Laveran noticed parasites, he called Oscillaria malariae, in the blood of malaria patient in 1880 (Bruce-Chwatt, 1981). The genus plasmodium was portrayed by Ettore Marchiafava and Angelo Celli in 1885 [Chavatte et al., 2007]. William MacCallum discovered the sexual stages of malaria parasite in 1897. In 1898, Camillo Golgi and others demonstrated that human malaria was transmitted by anopheline mosquitoes (Cox, 2010).
Chloroquine was discovered in 1934 by Hans Andersag (CDC, 2016). The liver stage of malaria parasite was elaborated by Henry Shortt and Cyril Garnham in 1948. In early 1950's, malaria was thought to be eliminated from the U.S. Then after, human infection with P. knowlesi was recognized in 1965.
Artemisinin was isolated from Qinghaosu plant (Artemisia annua) in 1971. Next, dormant stages in the liver were demonstrated in 1982 by Wojciech Krotoski (Cox, 2010; David, 2006; CDC, 2016). Polymerase chain reaction (PCR) based malaria detection was depicted in the early 1990's (Snounou et al., 1993) and mean while malaria rapid diagnostic tests (RDTs) were developed (Dietze et al., 1995).
2.1.2 Etiology and Vectors of Malaria
The causative agents for malaria infection are among the genus Plasmodium and phyllum Apicomplexa (Morrissette and Sibley, 2002). The parasite is thought to have originated from Dinoflagellates, photosynthetic protozoa. There are more than 200 different species of Plasmodium. At least 13 species are pathogenic to humans (Chavatte et al., 2007; Liu et al., 2010). Other species infect other animals, including monkeys, rodents, and reptiles (Gueriard et al., 2010). Five of the human pathogens, P. falciparum, P. vivax, P. ovale (two species) and P. malariae, are well known etiologic agents for human malaria. Disease with knowlesi, monkey malaria parasite, occur in people when an Anopheles mosquito infected by a monkey bite humans (WHO, 2015).
Malaria is transmitted majorly via bites of the genus Anopheles mosquitoes, which includes 537 recognized species and most (87%) have been formally named (Harbach, 2013). Nearly, 70 of these species are able to transmit Plasmodium parasite to human hosts and 41 of 70 are considered to be dominant vector species (DVS) (Service and Townson, 2002). Due to residence of the parasite in red blood cells (RBCs), malaria can also be transmitted via blood transfusion, organ transplant, or shared use of needles or syringes contaminated with blood. A new born baby may also acquire congenital malaria from her/his mother before or during delivery (Owusu-Ofori, 2010; Manitoba, 2015). Furthermore, malaria transmission can largely be affected by global weather patterns, including El Nino and La Nina (Parham et al., 2011; PMI, 2014).