In this article we will discuss about the histology of malarial parasite.
The malarial parasites belonging to the Genus, Plasmodium, possess a life cycle which shows an alternation of generation accompanied by an alternation of host. Schizogony of malarial parasite (asexual cycle) occurs in the red blood cells and also endothelial cells of inner organs in vertebrate host, while the sexual phase of the cycle occurs in blood sucking insects; for mammalian forms these are anopheline mosquitoes and for the avian forms, culicine mosquitoes.
The genus Plasmodium in human blood has been first discovered by Laveran (1880). Golgi (1885) discovered the erythrocytic schizogony in human, Bignemi (1898) observed the mosquito cycle of Plasmodium vivax and Garnham, Bird and Baker discussed various stages of the parasite under electron microscope in the year of 1963.
Plasmodium belongs to subphylum—Sporozoa, which includes all the parasitic unicellular forms. Most of them are endoparasites and are well adapted to the parasitic mode of life, the sporozoans usually have two hosts—definitive and intermediate. Definitive hosts are those hosts which provide the sexual stage of the parasite and the intermediate hosts which provide the asexual stage or any larval stage of the parasite.
Out of the various diseases which are caused by mosquito, the malaria is the most common and well known disease in India. The word ‘malaria’ is derived from two Italian words, mala (bad) and aria (air) meaning “bad air”. In 1898 Sir Ronald Ross first discovered the role of female Anopheles mosquito in the spread of the malarial parasite. So that female Anopheles mosquito acts as a vector of the malarial parasite.
He made this discovery when he was working at P. G. Hospital (now named as SSKM Hospital) in Kolkata. For this significant contribution in the field of medical science, Dr. Ronald Ross was awarded Nobel Prize in 1902.
Causative Organism of Malarial Fever:
The malarial fever is caused by the sporozoan endoparasite known as Plasmodium.
The species of Plasmodium creating the malaria in man are:
Plasmodium falciparum Welch, 1897
P. malariae Grassi and Feletti, 1890
P. ovale Stephens, 1922
P. vivax Labbe, 1899
Kinds of Malariae in Man:
The malarial disease is caused by the four different species of Plasmodium and each species manifests a bit difference from the other species and these are mentioned below:
i. Benign tertian malaria is caused by Plasmodium vivax. In this type, the fever takes place every 48 hrs. interval i.e., on every 3rd day. There is a low death rate.
ii. Malignant tertian malaria is caused by P. falciparum. Here the fever occurs every 48 hrs. interval but there is high fever. This kind of malaria is dangerous as there is high death rate.
iii. Quarter malaria is caused by P. malariae. The fever occurs every 72 hrs. interval i.e.; on every 4th day.
iv. Mid-tertian malaria is caused by P. ovale. The fever takes place every 48 hrs. interval.
