Genetic variability of cloned Cytauxzoon felis ribosomal RNA ITS1 and ITS2 genomic regions from domestic cats with varied clinical outcomes from five states.

Cytauxzoon felis is a tick-borne hemoparasite that causes cytauxzoonosis in domestic cats in the United States. Historically, feline cytauxzoonosis was reported to be nearly always fatal. However, increasing evidence of cats surviving acute infection and/or harboring a chronic, subclinical infection has suggested the existence of different C. felis strains that may vary in pathogenicity. In this study, the intraspecific variation of the C. felis first and second ribosomal RNA internal transcribed spacer (ITS1, ITS2) regions was assessed for any clinical outcome or geographic associations. Sequence data were obtained for 122C. felis ITS1 and ITS2 clones from 41 domestic cat blood samples from Arkansas, Kansas, Missouri, Oklahoma, and Texas. Seven previously reported ITS1 region sequences were found, and a previously undescribed 23-bp insert was detected in cloned ITS1 sequences from a domestic cat in Missouri and two cats in Oklahoma. Four previously reported ITS2 region sequences were identified, and a 40-bp insert similar to that previously reported in C. felis of a domestic cat from Arkansas and pumas was detected in 18 cloned C. felis sequences from 12 domestic cats. One clone contained both the 23-bp insert and 40-bp insert within the ITS1 and ITS2 regions, respectively. Combined ITS1 and ITS2 sequence genotypes revealed that C. felis sequences from 27 cats (72/122 clones) corresponded to four previously described genotypes, ITSa, ITSc, ITSd, and ITSn. Five clones with the novel 23-bp insert from three cat isolates represented two new genotypes, ITSaa and ITSbb. Genotypes ITScc, ITSdd, ITSee, ITSff, ITSgg, and ITShh denoted 13 clones that matched prior sequences but had no previously assigned genotype. Genotypes ITSii through ITStt comprised 32 clones that were similar to, but did not exactly match, previously described genotypes. Twenty-five cats had C. felis infections with multiple ITS genotypes. Considerable C. felis genetic diversity was revealed with no significant geographic or clinical outcome associations.

Molecular characterization of Trypanosoma (Megatrypanum) spp. infecting cattle (Bos taurus), white-tailed deer (Odocoileus virginianus), and elk (Cervus elaphus canadensis) in the United States.

In the United States, the generally non-pathogenic trypanosome of cattle is designated Trypanosoma (Megatrypanum) theileri and is distinguished morphologically from Trypanosoma (M.) cervi, a trypanosome originally described in mule deer and elk. Phylogenetic studies of the Megatrypanum trypanosomes using various molecular markers reveal two lineages, designated TthI and TthII, with several genotypes within each. However, to date there is very limited genetic data for T. theileri, and none for the Megatrypanum trypanosomes found in wild ungulates, in the U.S. In this study U.S. isolates from cattle (Bos taurus), white-tailed deer (Odocoileus virginianus) (WTD), and elk (Cervus elaphus canadensis) were compared by ribosomal DNA (rDNA) sequence analysis and their incidence in cattle and WTD in south Texas counties was investigated. Phylogenetic analyses showed clear separation of the bovine and cervine trypanosomes. Both lineages I and II were represented in the U.S. cattle and WTD parasites. Lineage I cattle isolates were of a previously described genotype, whereas WTD and elk isolates were of two new genotypes distinct from the cattle trypanosomes. The cattle isolate of lineage II was of a previously reported genotype and was divergent from the WTD isolate, which was of a new genotype. In La Salle, Starr, Webb, and Zapata counties in south Texas a total of 51.8% of white-tailed deer were positive for trypanosomes by 18S rDNA PCR. Of the cattle screened in Webb County, 35.4% were positive. Drought conditions prevailing in south Texas when the animals were screened suggest the possibility of a vector for Trypanosoma other than the ked (Lipoptena mazamae) and tabanid flies (Tabanus spp. and Haematopota spp.).