Four Killer Protists
By; Seth H.
Malaria is a serious and sometimes fatal disease caused by a parasite that commonly infects a certain type of mosquito which feeds on humans. People who get malaria are typically very sick with high fevers, shaking chills, and flu-like illness. Four kinds of malaria parasites have long been known to infect humans: Plasmodium falciparum, P. vivax, P. ovale, and P. malariae. Recently, it has been recognized that P. knowlesi, a type of malaria that naturally infects macaques in Southeast Asia, also infects humans, causing malaria that is transmitted from animal to human ("zoonotic" malaria). P. falciparum is the type of malaria that is most likely to result in severe infections and if not promptly treated, may lead to death. Although malaria can be a deadly disease, illness and death from malaria can usually be prevented.
African sleeping Sickness
Caused by the protist protozoa Trypanosoma brucei, this disease is symptomized by fever and headaches in the initial stages, which may be accompanied by vital organ dysfunction, followed by swelling of the lymph nodes in the second stage. The last stage is characterized by mental confusion and disruption of the sleep cycle, often reversing the diurnal-wakefulness-nocturnal-slumber sequence. This is accompanied by distorted coordination and extreme fatigue. The parasites invade the lymphatic system and gradually cross over to the blood stream. The last stage occurs when they bypass the blood brain barrier and invade the central nervous system. These protists are usually transmitted from the bite of the tsetse fly which acts as both the primary host and the disease vector.
Spread by blood sucking assassin bugs, this disease is caused by the protozoa Trypanosoma cruzi which is passed on to the secondary hosts, humans, when these bugs feed on the hosts' blood and defecate immediately near the site of the bite. The protists carried in the bug excreta enter the host's body when the site of feeding is scratched and the skin surface is aggravated as such. They enter through the wound, undergo binary fission to differentiate into trypomastigotes which invade the blood stream.
This is a form of diarrhea caused by the infectious protist Giardia lamblia. Giardia cysts can be transmitted on coming in contact with an infected person who does not maintain proper personal hygiene or by coming in contact with contaminated water. The parasite invades the small intestine and the common symptoms are watery stool, flatulence and accumulation of foul-smelling stomach gas, vomiting, abdominal cramps and foul breath.