Table 1 Summary of common techniques used for diagnosis of BLV prevalence
From: Epidemiology and genetic diversity of bovine leukemia virus
Diagnostic assay | Sample | Target | Advantages | Disadvantages | References | |
|---|---|---|---|---|---|---|
Type | Assay | |||||
Serological test | AGID | Serum | Antibodies (p24, gp51) | Specific, simple, and easy to perform Large scale screening Less expensive Rapid | Less sensitive and inconclusive Cannot evaluate disease states of infected cattle | Aida et al., 1989 [47] |
Wang et al., 1991 [48] | ||||||
Monti et al., 2005 [49] | ||||||
Kurdi et al., 1999 [50] | ||||||
Jimba et al., 2012 [43] | ||||||
Naif et al., 1990 [55] | ||||||
ELISA | Serum Milk Bulk milk | Antibodies (p24, gp51) | Specific and sensitive Large scale screening Time saving | False negatives (cattle in early infection phase) False positive (maternally derived antibodies) Cannot evaluate disease states of infected cattle A number of controls and a plate reader required Results require interpretation | Naif et al., 1990 [55] | |
Burridge et al., 1982 [56] | ||||||
Schoepf et al., 1997 [53] | ||||||
Kurdi et al., 1999 [50] | ||||||
Monti et al., 2005 [49] | ||||||
Jimba et al., 2012 [43] | ||||||
Zaghawa et al., 2002 [52] | ||||||
PHA | Virus particle | BLV glycoprotein | Sensitive Specific detection of BLV Large scale titration Less expensive Rapid | Affected by pH and temperature Hemagglutination activity reduced by trypsin, potassium periodate, and neuraminidase | Fukai et al., 1999 [51] | |
RIA | Serum | Antibodies (p24) | Sensitive Able to detect BLV during the early period of infection | Cannot be used for mass screening | Levy et al., 1977 [54] | |
Nguyen et al., 1993 [57] | ||||||
Proviral DNA detection | Single PCR; Semi-nested PCR; Nested PCR | Blood PBMC Tumor sample Buffy coat Milk somatic cells Semen Saliva Nasal secretions | Provirus | Direct, fast, sensitive A variety of samples can be used BLV detection during the early phase of infection or in the presence of colostrum antibodies Can detect new infections, before the development of antibodies to BLV | Unable to detect BLV when the proviral load is too low Cross contamination occurs easily Requires specific primers Requires equipment (PCR machine) False negatives in the presence of PCR inhibitory substances in samples Requires internal control Needs confirmatory testing, such as sequencing | Monti et al., 2005 [49] |
Kurdi et al., 1999 [50] | ||||||
Zaghawa et al., 2002 [52] | ||||||
Tajima et al., 1998 [64] | ||||||
Tajima et al., 2003 [61] | ||||||
Real-time PCR | Blood PBMC Tumor sample Buffy coat Milk Somatic cells Semen Saliva Nasal secretions | Provirus | Direct, fast, sensitive Low risk of contamination A variety of samples can be used Distinguishes EBL from SBL BLV can be detected during the early phase of infection or in the presence of colostrum antibodies Quantitative measurement of proviral load | Requires internal control Requires positive controls of different concentrations Requires specific primers and probes Require equipment (real-time PCR machine) Expensive Complicated sample preparation procedure | Somura et al., 2014 [68] | |
Lew et al., 2004 [69] | ||||||
Jimba et al., 2010 [70] | ||||||
Jimba et al., 2012 [43] | ||||||
Tawfeeq et al., 2013 [67] | ||||||
Brym et al., 2013 [66] | ||||||
Takeshima et al., 2015 [71] | ||||||
Direct blood-based PCR | Blood | Provirus | Cost-effective No need for DNA purification Low risk of contamination | Unable to detect BLV when the proviral load is too low Results in failure if there are mismatches between the PCR primers and BLV sequences Relatively low sensitivity | Nishimori et al., 2016 [72] | |
Takeshima et al., 2016 [73] | ||||||