Some diseases caused by Protozoans

Protozoans are useful as well as harmful to us. Protozoans cause many diseases in human being. The below article will provide you with some diseases caused by protozoans. You will also find the symptoms and prevention methods of diseases in below article.


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:
  1. Washing hand before taking meals and after defecation with soap.
  2. Use boiled drinking water.
  3. Safe disposal of faces is essential.
  4. Proper sanitation of pen drains, street and roads.

By ematin, an alkaloid, patient gets temporary relief. Fumagillin, erythromycin, and metronidazole have also proved useful for the treatment of the disease.


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:
  1. Treatment of patient.
  2. Prophylaxis or prevention of the infection.
  3. Destruction of the vector mosquitoes.

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:
  1. Use of mosquito nets, adequate screening of the door, windows and ventilators, covering the parts of the body while sleeping can prevent the biting of the mosquitoes.
  2. Application of repellents anti-mosquito creams and mustard oil prevents the mosquito bit.
  3. Fumigation also prevents mosquitoes.
  4. We should check the places where the mosquito can breed and should be destroyed.

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:
  1. Tryponosomiasis can be reduced by killing the parasite Glossina palpalis and by destroying its habitat. It can be killed by D.D.T. spray.
  2. Domestic and wild mammals who act as reservoir host be killed but it is impracticable.
  3. Preventive measures should be adopted to avoid tsetse fly bit.
  4. A single intramuscular injection of 4 mg/kg body weight of pentamidine remains effective for about six months.


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.


Author: Swati Sharma23 Aug 2020 Member Level: Gold   Points : 2

Very informative and knowledgeable article has been written
Many diseases are caused by protozoa, which treatment is also available and possible, but we should be careful and take precautions. Some more diseases related to it are as follows -
Diarrhea in children - We often see diarrhea problem in young infants. Let us tell you that a protozoa named Giardia is responsible for this. Due to this, the problem of thin diarrhea arises in infants, due to which, essential elements like water and minerals are also lacking in their body. Actually, in places where there is dirt, such problem is more. Its infection spreads through the mouth to the small intestine. It also damages the intestine, due to which this disease can disturb the child for a long time.
This is a tooth-gum disease. This disease of the gums is caused by bad teeth and keeping teeth dirty, in this disease, the gums become puffy and bad and they start bleeding.
Sleepless disease is also a symptom of protozoan infection. Some others are -
Redness at the place of itching
Lack of blood

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