The following points highlight the twelve parasitic protozoans causing diseases in animals. Some of the protozoans are: 1. Trichomonas hominis 2. Trichomonas gallinae 3. Trichomonas gallinarum 4. Trichomonas foetus 5. Histomonas maleagridis 6. Trypanosoma species 7. Sarcocystis linedamanni 8. Eimeria species and Others.
Protozoa # 1. Trichomonas hominis:
It is a Mastigophra inhabiting the ileo-caecal region of monkeys, cats and dogs and is supposed to cause diarrhoea and dysentery. Its infection occurs due to ingestion of contaminated food and water which may contain cysts.
Protozoa # 2. Trichomonas gallinae:
It lives in the epithelial lining of the oesophagus and crop of pigeons, turkeys, fowls, etc. and sometimes also lives in liver and lungs. It causes necrotic nodules in these organs.
Protozoa # 3. Trichomonas gallinarum:
It dwells in the epithelium of lower intestine and liver of turkeys and fowls. It causes disease similar to black head disease.
Protozoa # 4. Trichomonas foetus:
Trichomonas foetus inhabiting the urinogenital system of cattle, horses and sheep. It causes abortions, delayed conception and inflammation of perputial sacs. Transmission takes place directly during coitus.
Protozoa # 5. Histomonas maleagridis:
It is a Mastigophora inhabiting the caecum and liver of turkeys and fowls and causes black head disease in them.
Protozoa # 6. Trypanosoma species:
Trypanosoma species also causes diseases in domestic animals.
The species of Trypanosoma causing diseases in various animals are as follows:
(i) Trypanosoma brucei causes nagana disease in domestic animals in Africa. Nagana is similar to sleeping sickness. Its vector is Glossina morsitans.
(ii) Trypanosoma evansi causes surra disease in horses, camels, dogs, mules and catties. Its vectors are flies Tabanus and Stomoxys. Surra occurs in India and various other regions and it is especially deadly in horses.
(iii) Trypanosoma equiperdum causes dourine, a disease of sex organs in horses. It is transmitted by contact during copulation.’ It has no vector.
(iv) Trypanosoma equinum causes Mai de Caderas in horses in South America. Its vector is a tabanid fly.
(v) Trypanosoma hippicum causes Murina or Deren gadera in horses and mules in Panama. Its vectors are flies.
Protozoa # 7. Sarcocystis linedamanni:
It is a sporozoan inhabiting the striped muscle fibres of sheep’s oesophagus. It causes degeneration of muscles.
Protozoa # 8. Eimeria species:
It is also a sporozoan and its many species dwell in various animals such as sheep, cattle, and birds. It causes dysentery and diarrhoea in them.
Protozoa # 9. Babesia bigemina:
It is a sporozoan parasite in erythrocytes (RBCs) of cattle. The parasite causes Texas fever or Red water fever destroying red blood cells. Texas fever is widespread in America and Australia where it kills many cattle. Its infection takes place through bite of vector female tick, Boophilus annulatus.
Protozoa # 10. Babesia canis:
It is parasitic in the red blood corpuscles of dog. It causes anaemia, malignant jaundice, fever in dogs. It is transmitted to dogs by biting of ticks.
Protozoa # 11. Babesia equi:
It is a parasitic in the red blood corpuscles of horses and causes anaemia, jaundice and paralysis of hind limbs. Its transmission to host takes place by biting of ticks.
Protozoa # 12. Nosema apis:
It is a sporozoan which dwells in the intestinal epithelium and Malpighian tubules of honey bees. It causes muscular disease in them and its infection is caused due to cytoplasmic inheritance.