Phylogenetic analysis by rRNA comparison of the highly pathogenic sheep-infecting parasites Theileria lestoquardi and a Theileria species identified in China.

SCHNITTGER L, HONG Y, JIANXUN L, LUDWIG W, SHAYAN P, RAHBARI S, VOSS-HOLTMANN A, AHMED JS

ANNALS OF THE NEW YORK ACADEMY OF SCIENCES.

Año: 2000 p. 271 - 275

0077-8923

In the Northwestern part of China there have been reports of clinical cases in small ruminants of a haemoparasite with the characteristics of Theileria hirci (T. lestoquardi). However, some properties of this parasite argue against its classification as T. lestoquardi. In this paper, we present evidence that T. lestoquardi and the Chinese Theileria isolate are distinct parasite species. Phylogenetic analysis of determined nucleotide sequences of small subunit ribosoma RNA (srRNA) genes of T. lestoquardi and the Chinese Theileria parasite show that they belong to different clades within the phylogenetic tree of piroplasms. The srRNA sequence of the Chinese parasite was found to be most closely related to T. buffeli, which, with T. sergenti, belongs to an evolutionary lineage of non-lymphoproliferative Theileria species. On the other hand, it was clearly divergent to a lineage of lymphoproliferative Theileri species: T. annulata, T. parva, T. taurotragi, and T. lestoquardi, the latter being most closely related to T. annulata.