Evaluation of the performance of cellular and serological diagnostic tests for the diagnosis of tuberculosis in an alpaca (Vicugna pacos) herd naturally infected with Mycobacterium bovis

Evaluation of the specificity of intradermal tuberculin and serological tests for diagnosis of tuberculosis in alpaca (Vicugna pacos) and llama (Lama glama) herds under field conditions in Peru

“…However, the significance of this dose-effect was limited on these TB-free herds, as it did not affect the outcome of the test (ie, it did not affect the Sp) and therefore its impact on the Se of the skin test should be further evaluated in infected herds. Axillary site has been usually preferred for intradermal tuberculin test in camelids although a recent study did not detect significant differences in the outcome using axillary or prescapular sites for diagnosis in naturally TB-infected alpacas (Bezos and others 2013) similarly to the present study.…”

“…Using the SCIT test, no reactors were detected regardless of the dose of PPDs (data not shown). These results demonstrate that the SIT test, a highly sensitive TB diagnostic technique in livestock that may be more limited in camelids (Bezos and others 2013), is also very specific. Significant differences on the quantitative result (mm) of those animals that received a dose of bovine PPD of 2500 IU on the cervical site were observed depending on the time of reading (72 hours>120 hours, Wilcoxon test, P=0.021).…”

“…Furthermore, camelids can be reservoirs of TB infection for other domestic and wild animals and human beings and, therefore, control of disease in these species is crucial for animal and public health (Zanolari and others 2009, Twomey and others 2010). Although there are no official data on the prevalence of TB in NWCs, several outbreaks have been reported in recent years in different European countries (Connolly and others 2008, Zanolari and others 2009, Garcia-Bocanegra and others 2010, Twomey and others 2010, Twomey and others 2012, Bezos and others 2013). Likewise, no information on the prevalence of TB in camelids in South American countries is available since no previous studies describing outbreaks in these countries have been published.…”

“…Serum samples from all the animals were collected in both herds just before and 120 hours post-PPD inoculation for detection of specific antibodies using a novel serological assay developed by Inmunología y Genética Aplicada SA (INGENASA, Madrid, Spain) and based on detection of anti-MPB83 antibodies by a double recognition ELISA (DR-ELISA) (Bezos and others 2013). Two dilutions of the same serum samples were assayed (1/25 and 1/50) and two different cut-off points (reactors when OD 450 >0.3 or OD 450 >0.4) selected for optimal Se and Sp according to manufacturer's instructions were evaluated (INGENASA).…”

Restructuring the RCVS fellowship

“…The author makes a reference to his previous work in alpacas which suggests a skin sensitivity of around 50 per cent but with a rather wide confidence interval (Bezos and others 2013).…”