Development of a diagnostic blood test for tuberculosis in alpacas (Lama paces)

Abstract

Vaccination of alpacas (Lama pacos) with heat-killed Mycobacterium bovis (BCG) in oil adjuvant produces an immune response that is able to be measured in vitro. Lymphocyte transformation was present 2 weeks after boosting while antibody as measured by the enzyme-linked immunosorbent assay was present 4-6 weeks after primary vaccination. Two vaccinated animals were positive to the intradermal skin test at the conclusion of the experiment and showed signs of systemic inflammation 72 hours after the skin test, while the controls remained negative for all tests. The BCG vaccine studies showed that these laboratory tests can also identify M. bovis-specific reactivity, so the technique has potential for the diagnosis of tuberculosis in alpacas. Apart from diagnosing M. bovis-specific reactivity, the blood test for tuberculosis may also be used to diagnose non-specific mycobacterial sensitisation in farmed New Zealand alpacas.

Evaluation of Methods to Improve the Diagnosis of Systemic Inflammation in Alpacas

“…In cattle, haptoglobin is considered a major APP as immune‐stimulation can raise concentrations from undetectable levels to concentrations increased by up to 100‐fold . This appears to be in contrast to alpacas in this and another study in which concentrations of approximately 1 mg/mL occurred before experiments . Measureable increases in haptoglobin concentrations after low‐dose LPS challenge in the present study suggest that more pronounced haptoglobin changes can be expected in clinical practice, where bacterial infections are common.…”

“…Previous reports on the use of haptoglobin assays in alpacas are sparse, but increased haptoglobin concentrations were observed in alpacas vaccinated with a Mycobacterium bovis vaccine . In that study, intradermal tuberculin skin testing resulted in increased serum haptoglobin concentrations of up to 0.44 mg/mL . The earliest significant increase in haptoglobin concentration was detected in TG‐alpacas at 36 hours, which is similar to cattle in which large increases are detected 2 days after inflammatory challenge .…”

“…Previous reports on the use of haptoglobin assays in alpacas are sparse, but increased haptoglobin concentrations were observed in alpacas vaccinated with a Mycobacterium bovis vaccine . In that study, intradermal tuberculin skin testing resulted in increased serum haptoglobin concentrations of up to 0.44 mg/mL .…”

Use of serological techniques for diagnosis of Mycobacterium bovis infection in a llama herd

“…The comparative tuberculin skin test in the postaxillary site is the recommended diagnostic test in the UK and many other countries, although this test has not been fully validated and is technically more difficult to perform in camelids than in cattle. Some small studies have reported reasonable sensitivity and specificity for this test (Thoen and others 1988, Johnson and others 1989, Stevens and others 1998, Cousins and Florisson 2005); however, others have suggested that it has a low predictive value (Bleem and others 1993, Hesketh and others 1994).…”

Current Diagnostic Methods for Tuberculosis in Zoo Animals

“…26,47 In naturally infected Bactrian camels, ELISA and immunoelectrophoresis detected antibodies to multiple mycobacterial species, including M. bovis, which may explain why camelids show a high frequency of falsepositive tuberculin reactions. Routine screening is recommended as part of their regular health evaluation and may be required by regulatory agencies for interstate or international movement.…”