Introduction Some protozoans live as harmless endocommensal in the host's body. These protozoans are termed as non-pathogenic. Those protozoans which produce diseases in human beings are called pathogenic protozoans. The pathogenic protozoans occur in all the classes of protozoa. More than 25 different species of parasitic protozoans are known to live in man alone which are responsible for several dreadful and fatal human diseases. The important diseases caused by protozoans and their causative protozoans are explained in this article.
Amoebiasis or dysentery Amoebiasis or dysentery is caused by Entamoeba histolytica . Amoebiasis is quite prevalent in tropical countries. The intestine of persons infected with Entamoeba histolytica develops ulcers due to which mucus and blood pass out with faeces along with cysts of Entamoeba histolytica . The patient develops headaches, fever and spasmatic pain in the abdomen. In acute and chronic cases, parasites reach the liver, heart, lungs, brain, etc. along with blood and damage the tissues of these organs.
Prevention : To prevent the infection of Entamoeba histolytica , fruits and vegetables should be eaten after washing with potassium permanganate. Contaminated food and water should not be taken. The following precautions should be followed to prevent the infection:
By ematin, an alkaloid, patient gets temporary relief. Fumagillin, erythromycin, and metronidazole have also proved useful for the treatment of the disease.
Malaria Although Malaria is noted from every part of the world yet it is more prevalent in tropical countries. However, in Africa, it is most common. About 11 crore people suffer from this disease in a year in the whole world. According to reports of the World Health Organization, about 1-2 lacs people die of malaria disease every year in the world. Most of these are children below the age of 5 years. Malaria is caused by the different species of Plasmodium .
In 1880, for the first time, Laveren observed Plasmodium in the blood of a person suffering from malaria. In 1887, Sir Ronald Ross observed that malaria is associated with mosquitoes. He observed that mosquito (female Anopheles) transfer these parasites into the blood of a healthy man when it penetrates hypopharynx or sucks the blood. Four species of Plasmodium are harboured by mosquitoes. These species are Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malariae. The patient suffering from malaria develops fever periodically in a week.
Control of Malaria: The malaria is the most severe and widely spread disease in India and Africa. Therefore, the Indian government has established a separate Anti -Malaria Department to control malaria through the National Malaria Eradication Programme (NMEP). The control of malaria disease involves:
The disease is diagnosed by a blood test of the patient during fever. After proper diagnosis treatment is given. Quinine and camoquin are employed for the treatment of malaria.
Preventions: It involves the elimination of mosquitoes and use of drugs:
African sleeping sickness African sleeping is caused by a flagellated Trypanosoma gambiense. Trypanosoma gambiense is found in the blood of man and other vertebrates. It may also be found spleen, lymph glands and cerebrospinal fluid. The disease sleeping sickness is preceded by anaemia, headache, fever and enlargement of liver and spleen. Trypanosoma gambiense is transferred from one host to another by tsetse fly Glossina palpalis It is very prevalent in Nigeria and Congo. When Trypanosoma gambiense enter the cerebrospinal fluid that surrounds the brain and the spinal cord of the patient, the patient loses consciousness and sleeping sickness comes to a fatal end.
Nowadays, two drugs Bayer 205 (Antrypol, Germanin or Suramin commercial names) and Pentamidine or Iomodine are used in the early stage of infection. When the parasites invade the central nervous system, these medicines are ineffective. Now, an arsenic compound Tryparsamide is used. Tryparsamide is also now superseded by Melarsoprol.
Prevention: The following precautions should be taken to prevent sleeping sickness:
Chagas Chagas is a disease of children, first intracellular in gonads, heart, muscles, brain, spinal cord, etc., later extracellular in blood. Chagas disease is accompanied by fever, diarrhoea, headache, anaemia, heart failure, etc. Chagas spreads by infection of wounds by contaminated faeces of blood-sucking vector bugs (triatomidae).
Kala Azar Kala Azar is malaria-like disease which is characterized by fever, anaemia and enlargement of liver and spleen. It also affects leucocytes, lymph glands, liver, spleen and bone marrow of man. It spreads by the bite of the vector sandfly (Phlebotomus).
Important Note: The medicine in this article is for knowledge purposes only. You should take medicines only on the advice of your physician.
Hakimuddin Kuwakhedawala is based in India with over 15 years experience as a teacher. Teaching and writing are his passion. Most of the articles of Hakimuddin are related to education, exam, environmental problems, etc.
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