Non-immunologic methods of diagnosis of babesiosis

Abstract

The diagnosis of tick-borne diseases such as babesiosis still depends on observing the parasite in the infected erythrocyte. Microscopic observation is tedious and often problematic in both early and carrier infections. Better diagnostic methods are needed to prevent clinical disease, especially when susceptible cattle are being moved into disease enzootic areas. This study evaluates two techniques for early diagnosis of Babesia bovis infections in cattle, DNA probes specific for the organism and fluorescent probes specific for nucleic acid. The radioisotopically labeled DNA probes are used in slot blot hybridizations with lysed blood samples, not purified DNA. Thusfar, the probe is specific for B. bovis and can detect as few as 1000 B. bovis parasites in 10 microliters of blood. The specificity of the fluorescent probe depends on the characteristic morphology of the babesia in whole blood samples, as determined microscopically. The fluorescent probe detects as few as 10,000 B. bovis parasites in 10 microliters os blood. The application of each method for laboratory and field use is discussed.

PCR-Based Detection ofBabesia ovisinRhipicephalus bursaand Small Ruminants

“…However, the method requires expertise because these parasites have similar morphological features and, therefore, may confuse the examiner when mixed infections occur. Serological tests were also used, but there are some difficulties with specificity and sensitivity [5]. An exact differentiation between haemoparasites is crucial to understanding their epidemiology.…”

“…and the lack of discrimination between acute infection and carrier state. Furthermore, false positive and negative results are commonly observed in these tests [5]. The use of alternative techniques, such as polymerase chain reaction (PCR), has become necessary to detect and identify Babesia infections effectively and has been reported in numerous recent studies [6, 7].…”

Development of Taqman-Based Real-Time PCR Assays for Diagnostic Detection of Babesia bovis and Babesia bigemina

“…6 However, the antibodies cannot always be detected in long-term carriers despite the presence of the parasite. 7 Furthermore, cross-reactivity of the antibodies against other Babesia species has limited the specificity of serological tests. 8,9 Polymerase chain reaction (PCR) assays for the diagnostic detection of Babesia parasites have the potential to provide rapidly qualitative results with high sensitivity, in particular, nested-PCR assay.…”

Molecular detection of Babesia bigemina infection in apparently healthy cattle of central plain zone of Punjab

“…Alternative diagnostic approaches like indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) are capable of detecting the antibody in carrier animals but suffer serious drawbacks of cross-reaction between B. bigemina and B. bovis and the lack of discrimination between previous exposure and current infections (Wagner et al 1992). However, recently a number of molecular techniques have been described that can detect and differentiate various species of Babesia in carrier animals (Oliveira et al 2005;Buling et al 2007;Ravindran et al 2008;Singh et al 2010).…”