GLIDERS

Neoplastic disease is not uncommon in gliders. A wide range of benign and malignant tumours have been docu­mented. The most important neoplastic disease in gliders is transponder (microchip) associated sarcoma, predomi­nantly a disease of feather-tailed gliders.

5.1 Transponder-associated neoplasia in gliders

Gliders, especially feather-tailed gliders, are highly suscep­tible to developing neoplasms at transponder (microchip) implantation sites (Vogelnest et al. 1997; Pessier et al. 1999; Johnson and Hemsley 2008; Whiteside et al. 2008) (Fig. 18.3 and Plate 18.1). Most are STS or fibrosarcomas, but other malignancies have also been observed, including osteosarcoma, infiltrative lipoma and myxosarcoma (Table 18.10). Some cause local cutaneous ulceration. The majority of these masses are typically discrete or locally invasive, though metastasis to the liver has been recorded

Table 18.6. Benign and pre-malignant neoplasms of dasyurids

¹ARWH 2018 case nos ^a11903.1; ^b11792.1; ^c7933.1; ^d10513.1; ^e10517.2; ^f9303.1; ^g8321.1; ^h8852.1; ⁱ11127.3; ^j11749.2; ^k7901.3; ^l7744.2; ^m4520.3; ⁿ11127.1; ^o11637.1; ^p8321.3; ²Ladds 2009; ³Holz 2008; ⁴Michael and Sangster 2010; ⁵Peck etal. 2019; ⁶Gonzalez-Astudillo etal. 2024

in one case (ARWH 2018 case no. 10682.1). Single cases of transponder-associated neoplasia have been documented in other marsupials, including sarcoma in a koala (Vogel- nest et al. 1997), carcinoma in a fat-tailed dunnart (Sminthopsis crassicaudatus) (ARWH 2018 case no.

9471.1), fibrosarcoma in a greater bilby (ARWH 2018 case no. 2582.1) and STS in a red-tailed phascogale (ARWH 2018 case no. 11106.1).

5.1.1 Treatment of transponder-associated neoplasia

In most cases animals clinically suspected to have tran­sponder-associated sarcoma were euthanased. One case of attempted treatment (excisional biopsy) is documented, though the animal died 11 d following surgery and was diagnosed with multicentric lymphosarcoma at necropsy (ARWH 2018 case no. 8630.2). These masses are often well-demarcated and mobile, suggesting they may be

Table 18.7. Malignant neoplasms of dasyurids

¹ARWH 2018 case nos ^a9611.3; ^b11549.1; ^c7373.1; ^d8852.2; ^e8854.3; ^f9919.1; ^g11106.1; ^h11106.2; ⁱ8709.1; ^j9471.1; ^k9470.1; ^l7901.3; ^m6779.2; ⁿ9206.2; ^o10201.1; ^p7744.2;, ^q9622.1; ^r8202.1; ^s8372.3; ^t10650.1; ^u7829.1; ^v12161.1; ^w12162.1; ²Holz 2008; ³Ladds 2009; ⁴Peck etal. 2019; ⁵Scheelings etal. 2014; ⁶Gonzalez-Astudillo etal. 2024; ⁷Elbert etal. 2019; ⁸Saunders etal. 2017; ⁹Anderson et al. 1990

Table 18.8. Benign neoplasms in macropods

Benign

amenable to resection if the animal is considered other­wise an appropriate surgical candidate.

5.1.2 Prevention of transponder-associated neoplasia

The use of alternative methods of identification, par­ticularly in feather-tailed gliders, has had mixed results. Visible implant elastomer (VIE) markings have been used on the ventral side of feather-tailed glider tails. In 9 of 10 feather-tailed gliders with VIE markings that had died, examination of associated tissue found microscopic evidence of granulomatous inflammation consistent with a foreign body reaction after a mini­mum of 12 mo following implantation (ZAA 2013). Additionally, VIE markings are impractical to use, col­ours are difficult to distinguish and some fade over time.

Because of the challenges with VIE implants in feather-tailed gliders, the current recommendation for transponder use in gliders is that smaller nano- or midi­chips be used in place of the larger standard chips (ZAA 2013). Additionally, clipping the fur before insertion to avoid potential introduction of fur into the subcutis is

recommended (L Vogelnest pers. comm.). With this pro­tocol, no cases of microchip-associated tumours have been seen in feather-tailed gliders for 5 yr at one institu­tion (L Vogelnest pers. comm.).

5.2 Other neoplasms in gliders

Other benign and malignant neoplasms documented in gliders are listed in Tables 18.11 and 18.12.

6.