Comparative Sensitivity of Two Tests for the Diagnosis of Multiple Hemoparasite Infection of Cattlea

Abstract

The purpose of this study was to evaluate the efficacy of light microscopy (LM) examination of blood smears and a multiplex polymerase chain reaction (MPCR) assay, in terms of their ability to detect cattle experimentally infected with Babesia bovis, Babesia bigemina, and Anaplasma marginale. Blood samples were collected from 32 intact, 1-2 year old, Holstein bulls, previous to and after simultaneous inoculation of culture-derived or field isolates of B. bovis- and B. bigemina-infected erythrocytes. To establish the triple hemoparasite infection, 16 of the bulls were also inoculated with a calf-derived isolate of A. marginale. The results showed that both tests had 100% specificity. In contrast, the sensitivities of the MPCR assay against the LM test were 93.5% and 70.9%; 96.7% and 100%; and 93.8% and 93.8% for B. bovis, B. bigemina, and A. marginale infection, respectively. The advantages and disadvantages of the MPCR assay to differentially diagnose cattle with multiple hemoparasite infection are discussed.

Theileria gilberti n. sp. (Apicomplexa: Theileriidae) in the Gilbert's Potoroo (Potorous gilbertii)

“…Microscopy and PCR were equally effective in the detection of Theileria in our samples. These results differ from a number of reports in which it was concluded that PCR was much more effective in detecting piroplasms than microscopy (Almeria et al 2001; Figueroa et al 1996; Homer et al 2000). In situations where circulating parasite levels are extremely low it can be very difficult to visually detect piroplasms in erythrocytes.…”

Prospective Study for the Detection of Anaplasma marginale Theiler, 1911 (Rickettsiales: Anaplasmataceae) in Costa Ricaa

“…Blood samples were processed as previously described 13,14 and packed erythrocytes were kept at −20°C until analyzed.…”

“…To amplify Anaplasma DNA from blood samples, 20 μl of sedimented erythrocytes from each animal were processed as previously described. 13,14 A thermocycler (Barnstead‐Thermolyne, Model Temptronics No DB 66925, Dubuque, Iowa) was used with 35 cycles at: 1 min at 95°C (2 min for the first cycle) for template denaturation; 1 min at 60°C for primer annealing; 1.5 min at 73°C for primer extension, and with a final extension at 73°C for 15 min.…”

“…Purified A. marginale DNA served as template for the PCR synthesis of a Digoxigenin‐(Boehringer‐Mannheim, Indianapolis, IN) labeled probe using Group II primers as previously described. 13,14 Group II primers comprised Am 11/12. The labeled 160 bp product was used as an internal probe for confirmation of specificity.…”

“…DNA hybrids were detected by an alkaline phosphatase‐based chemiluminescent reaction as described before. 13,14…”