The common zoonotic protozoal diseases causing abortion

Abstract

Toxoplasmosis, neosporosis, sarcosporidiosis (sarcocystosis) and trypanosomiasis are the common zoonotic protozoal diseases causing abortion which caused by single-celled protozoan parasites; Toxoplasma gondii, Neospora caninum, Sarcocystis spp and Trypanosoma evansi, respectively. Toxoplasmosis is generally considered the most important disease that causing abortion of both pregnant women and different female animals throughout the world, about third of human being population had antibodies against T. gondii. The infection can pass via placenta, causing encephalitis, chorio-retinitis, mental retardation and loss of vision in congenitally-infected children and stillbirth or mummification of the aborted fetuses of livestock. Neosporosis is recognized as a major cause of serious abortion in varieties of wild and domestic animals around the world particularly cattle, the disease cause serious economic losses among dairy and beef cattle due to decrease in milk and meat production. While unlike toxoplasmosis, neosporosis is not recognized as a human pathogen and evidence to date shows that neosporosis is only detected by serology in the human population. Sarcosporidiosis also can cause abortion in animals particularly cattle, buffaloes and sheep with acute infection through high dose of infection with sarcocysts. On the other hand, humans have been reported as final and intermediate host for sarcosporidiosis but not represent a serious health problem. Trypanosomiasis by T. evansi cause dangerous infection among domestic animals in tropical and subtropical areas. Several cases of abortion had been recorded in cattle and buffaloes infected with T. evansi while, a single case of human infection was reported in India. Trichomoniasis and babesiosis abortion occurs with non-zoonotic Trichomonas and Babesia species while the zoonotic species had not been incriminated in induction of abortion in both animals and man. The current review article concluded that there is still need of wide scope for evaluation of the zoonotic impact and control of these diseases.

Keywords: Abortion; Neospora; Sarcocystis; Toxoplasma; Trypanosoma; Zoonotic protozoa.

Fig. 1

Toxoplasma gondii life cycle

Fig. 2

T. gondii infective stages; Tachyzoites (a), tissue cysts (b) and oocysts (c) (×400)

Fig. 3

Neospora caninum life cycle

Fig. 4

Neospora caninum infective stages; Tachyzoites (a), tissue cysts (b) and un-sporulated and sporulated oocysts(c) (×400)

Fig. 5

Srcocystis sp. life cycle

Fig. 6

Sarcocystis sp. Infective stages; oocyst and sporocysts (a), macroscopic sarcocysts in muscles (b) and microscopic sarcocysts contain bradyzoites (c) (×400)

Fig. 7

T. evansi trypomastigote in Giemsa-stained blood smear

Fig. 8

Some of the potential vectors of Trypanosoma evansi; Tabanus (a), Haematobia (b), Hippobosca (c) and Stomoxys (d)