Medical Reasons NOT to Microchip

RDOWS  POSITION STATEMENT ON MANDATORY MICROCHIPPING

 

Responsible Dog Owners of the Western States opposes any mandated microchipping of privately held domestic pet animals. The choice of whether to or whether not to microchip should be based upon all available information; and left strictly up to the owner to make for his/her animals. Our research has discovered potential health risks that are posed to domestic pet animals from microchip emplacement. Due to space only two of several findings will be cited:

(1) Vet Pathology 43:545-548 (2006) (c) 2006 American College of Veterinary Pathologists.

 

Fibrosarcoma with Typical Features of Postinjection Sarcoma at Site of Microchip Implant in a Dog: Histologic and Immunohistochemical Study - M. Vascellari, E. Melchiotti and F. Mutinelli Abstract

 

A 9-year-old, male French Bulldog was examined for a subcutaneous mass located at the site of a microchip implant. Cytologic examination of the mass was suggestive of a malignant mesenchymal neoplasm. Histologically, the mass was confirmed as a high-grade infiltrative fibrosarcoma, with multifocal necrosis and peripheral lymphoid aggregates. By immunohistochemistry, the sample was investigated for vimentin, smooth-muscle actin (SMA), CD3, CD79, and CD18.  

 

All the neoplastic cells were positive for vimentin. Scattered cells at the periphery of the lesion were also positive for SMA, highlighting a myofibroblastic phenotype. The lymphoid cells were positive for CD18 and CD3. No aluminum deposits were detected by the aurintricarboxylic acid method. A diagnosis of fibrosarcoma morphologically similar to feline post injection sarcomas was made. Fibrosarcomas at the site of injections have been reported in dogs and ferrets. Furthermore, neoplastic growth at the site of microchip implant in dog and laboratory rodents has been described.

Key words: Dog; fibrosarcoma; immunohistochemistry; microchip.
Marta Vascellari, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, 35020 Legnaro (PD) (Italy).

(2) Tumors in long-term rat studies associated with microchip animal identification devices.
 

Tumors surrounding implanted microchip animal identification devices were noted in two separate chronic toxicity/oncogenicity studies using F344 rats. The tumors occurred at a low incidence rate (approximately 1 percent), but did result in the early sacrifice of most affected animals, due to tumor size and occasional metastases. No sex-related trends were noted. All tumors occurred during the second year of the studies, were located in the subcutaneous dorsal thoracic area (the site of microchip implantation) and contained embedded microchip devices. All were mesenchymal in origin and consisted of the following types, listed in order of frequency: malignant schwannoma, fibrosarcoma, anaplastic sarcoma, and histiocytic sarcoma. The following diagnostic techniques were employed: light microscopy, scanning electron microscopy, and immunohistochemistry. The mechanism of carcinogenicity appeared to be that of foreign-body induced tumorigenesis.

Centre national de la recherche scientifique (21/09/2000) 2001, vol. 52, no 6, pp. 569-575 (24 ref.), pp. 483-491

 

Responsible Dog Owners of the Western States (RDOWS)

Cherie Graves, chairwoman, paragon@surf1.ws
Hermine Stover hermine@endangeredspecies.com