Theileria annulata seroprevalence among different cattle breeds in Rajshahi Division, Bangladesh

Abstract

An epidemiological survey of Theileria annulata infection was undertaken in a cattle population in Rajshahi Division, Bangladesh. The local cattle breeds from the area (North Bengal Gray and Deshi) and crosses between the local breeds and Holstein cattle were predominantly screened. In total, 192 cattle serum samples were collected in two areas of Rajshahi Division, the Rajshahi District (n=147) and Natore District (n=45). The samples were screened with an enzyme-linked immunosorbent assay using T. annulata surface protein (TaSP) as the antigen. The seroprevalence was 80.0% (36/45) in Natore and 20.4% (30/147) in Rajshahi. A logistic regression analysis showed that the sampling location was significantly associated with seropositivity, whereas age, sex and breed were not. Although the logistic regression analysis did not show a linear dependence on age, we considered age-specific seroprevalence separately in the two districts. Seroprevalence did not differ significantly among age categories in the Natore District. In contrast, all the cattle <1 year old in the Rajshahi District were seronegative (11/11). Seroprevalence in the 1- and 2-year-old cattle was significantly lower in the Rajshahi District than in the Natore District. In the older age categories (3, 4 and >5 years), seroprevalence did not differ significantly between the Natore and Rajshahi Districts. These results suggest that the cattle in the Rajshahi District were sporadically exposed to T. annulata, whereas most cattle in the Natore District became infected during an early phase of life.

Fig. 1.

Reactivity against TaSP of T. olientalis seropositive and negative cattle sera. (A) SDS PAGE of TaSP protein expressing E. coli lysate, fusion protein with TaSP and GST purified using Glutathione Sepharose 4B and TaSP protein separated from GST with PreScissionProtease. (B) Western blotting analysis of the separated TaSP. Obtained TaSP protein was applied for SDS PAGE and reacted with T. olientalis seropositive sera (lanes 1 and 2) and seronegative sera (lanes 3 and 4). Gray arrow, black arrow and open arrowhead indicate fusion protein with TaSP and GST, TaSP and trace amount of contaminated protein.

Fig. 2.

Seroprevalence of T. annulata in cattle in Bangladesh. (A) Location of the study areas. Gray and deep-gray areas on the map show Rajshahi Division and the Natore District, respectively. Inserted map shows the Natore District. The black area indicates Singra Upazila in the Natore District. (B) Distribution of absorbance values on the anti-TaSP ELISA. Black and gray bars indicate Japanese and Bangladesh cattle data, respectively (n=37 and 192, respectively). Dotted line indicates the calculated cut-off value. (C, D) Seroprevalence in the two sampling areas and sexes. 95% CIs of seroprevalence are also indicated.

Fig. 3.

Seroprevalence of T. annulata in cattle in Natore (open circles) and Rajshahi (solid circles). 95% CIs of seroprevalence are also indicated. Seroprevalence patterns by sex (A), breed (B) and age categories (C).