No effect of inoculation site and injection device on the skin test response of red deer to the intradermal injection of Mycobacterium avium-derived purified protein derivative (PPD)

Abstract

Mycobacterial diseases are important health issues in farmed deer. The single intradermal tuberculin test is the standard test for tuberculosis testing in deer. We studied two factors which might influence the response of deer to skin testing: the inoculation site and the injection device. Deer included in this study were 2.5 years old farmed red deer (Cervus elaphus) hinds (n = 80). Two areas of 3 cm × 3 cm were shaved at the left side of the neck. Site A (SA) was situated about 10 cm caudal to the head, while site B (SB) was 10 cm caudal to SA. All hinds received at the same time two 0.1 ml inoculations of Mycobacterium avium derived purified protein derivative (aPPD). One inoculation was made by syringe and the other one with the needle-free syringe Dermojet. To test the inoculation site effect, half of the animals were inoculated by Dermojet in SA and by syringe in SB to compare with the inoculation in SA by syringe and Dermojet in SB in the other half. No differences were recorded for the injection device nor for the inoculation site. Ten hinds had a skinfold increase larger than 30 tenths of mm by any injection device and inoculation site. Seven (9%) and 6 (8%) hinds were classified as positive by syringe and Dermojet, and at the anterior or posterior inoculation site, respectively. The distribution of skinfold thickness increases did not differ by injection device. Our findings support the needle-free Dermojet syringe as a suitable tool for skin-testing in red deer and suggest no relevant effect of the position of the inoculation site along the neck in red deer.