Molecular identification of ovine Theileria species by a new PCR-RFLP method.

Theileria spp. infect wild and domestic ruminants in the tropical and subtropical regions of the world. Two species, T. lestoquardi and T. ovis, are suspected to cause ovine theileriosis in Iran. The epidemiological aspects of ovine theileriosis in Iran are poorly understood, and further investigations by sensitive and precise techniques are required. In this study, the use of a nested PCR for amplification of a fragment of the 18S ribosomal DNA from virtually all species of Theileria is described. For differentiation of various Theileria spp. a RFLP assay was developed as a diagnostic tool enabling direct, concurrent, highly specific and sensitive identification of Theileria spp. The sensitivity of the nested PCR for Theileria species was 10(-5)% parasitemia. Restriction fragment length polymorphism (RFLP) of the PCR products allowed differentiation between three different Theileria species (T. annulata, T. lestoquardi and T. ovis) and seems to be useful for differentiation of other species such as T. separata and Theileria spp. china. From 100 field blood samples obtained from sheep in East and South-East Iran, 56% were positive for Theileria spp. by nested-PCR compared with 21% by microscopic examination. Out of 56 positive samples, 12.5% (7/56) were positive for T. ovis and 87/5% (49/56) were positive for T. lestoquardi. This is the first report in which T. ovis has been detected in Iran using molecular identification techniques.

Seroprevalence of Toxoplasma gondii infection in stray and household cats in Tehran.

The prevalence of anti-Toxoplasma gondii specific IgG in stray and household cats in Tehran was determined by Indirect Fluorescent Antibody Test (IFAT) on serum samples from 100 cats (50 stray and 50 households). Overall infection rate was 63%. The infection rate in stray cats (90%) was significantly higher (p<0.001) than that of household cats (36%). Last serum positive dilutions varied from 1: 32 to 1: 512 titres in which the highest percentage (27%) was for 1:256 and the least (4.8%) was at 1:32. The rate of infection between male and female cats of both groups was not significantly different; 90.3% versus 89.5% for male and female in stray cats, respectively. Different sexes of household cats were seropositive at the same rate (36%). A high positive correlation (r(2)=0.97) between age and the rate of infection was observed. The prevalence of Toxoplasma gondii infection in cats in Tehran was high, especially in stray cats which are probably the main source of Toxoplasma infection in this area.