Microchip Safety and Efficacy
Microchip Transponders and Cancer – "Is there any evidence that tumours form at
the site of transponder implantation in companion animals?"Rumours and media reports from various countries have recently hinted that implanting
transponders into companion animals may predispose them to tumour development at
the site of implantation.
The WSAVA Microchip Committee has reviewed the available evidence and come to theconclusion that from the tiny number of such cases reported compared to the huge
numbers of animals that have been implanted this effect is extremely small, if it exists atall. The benefits of transponder implantation, backed up with a reliable, accurate andavailable database, far outweigh this risk. Further details and the WSAVA Microchip
Committee position is provided below.
A Request for Information
However, in order to monitor the situation the Committee would be interested to receive
details of any cases were tumours have developed in companion animals at the site oftransponder implantation and where there is suspicion of an association. In the first
instance details should be sent to the WSAVA secretariat at fasanne@fasanne.dk.
WSAVA Microchip Committee Position on Microchips and Cancer
Reports of concerns about a possible link between the implantation of RFID
transponders and the formation of tumours have been brought to the attention of theWSAVA Microchip Committee.
1) Although these reports refer to scientific studies conducted in the 1990’s no scientificreference is made to allow us to check the original papers
2) The Committee is aware of more recent scientific papers which have reported tumour
formation at the site of implanted transponders in mice. The mice involved in thesestudies were either inbred strains or strains that have been genetically modified topredispose individual animals to cancer formation.
3) Many studies show that it is dangerous to transpose results from experiments in one
species to other species, eg from genetically modified mice to normal pet dogs and cats.
4) Transponder safety has been reviewed by many national regulatory authorities
responsible for the approval of implantable medical devises. These authorities haveapproved transponders as safe and effective ways of permanently identifying animals.
Such approval would not have been granted if there had been significant evidence that
implanting transponders induce tumour formation in the domestic animals concerned.
5) Many millions of companion animals have subsequently been implanted around theworld with a tiny proportion reporting any type of problem. In the UK where there has
been an informal reporting system for adverse reactions for over ten years only two of
the 3.7 million implanted animals recorded on the Petlog database have been reported

as developing a tumour at the site of implantation. In one of these cases the pathologist
reported that the transponder was incidental to the tumour formation. Overall, theCommittee is aware of less than ten reports of tumours forming in companion animals
associated with an implanted microchip.
6) Millions of animals have carried their transponders for most of a natural life time
without any adverse effects.
7) Conversely many thousands of implanted animals have been reunited with theirowners after going missing by tracing the owner through a reliable database.
Conclusion
While it is not possible to claim that the reaction to an implanted transponder in acompanion animal will NEVER induce tumour formation, the Committee is unanimouslyof the opinion that the benefits available to implanted animals far outweigh any possible
risk to the health of the animal concerned.
From Dr. Linda Lord, an RFID researcher at Ohio State University
in the USA
There is no evidence to suggest that companion animals implanted with a microchip are
at a higher risk for developing a tumor. The mice used in the studies where anassociation between a microchip and development of a tumor occurred were genetically
predisposed to cancer and do not represent the genetic diversity we see in our dogs andcats. In the United Kingdom where over half of the dog population has a microchip, theBritish Small Animal Veterinary Association has established a formal system for thereporting of adverse events related to microchips, including tumors. In ten years ofcollecting data, only 2 tumors were reported to their adverse event registry. When you
weigh this extremely rare event against the thousands of pets that are reunited
worldwide each year from a microchip, it seems obvious that the benefits frommicrochipping far outweigh any small risk from a tumor. All of my pets are microchipped
and all my future pets will be as well. I don't every worry about cancer from a microchip, Iworry about my pets getting lost and finding them.
___________________________________________WSAVA Microchip Committee: Failed Transponders
Although rare, failed microchips (transponders) do occur in previously implanted
animals. Additionally, some animals are implanted with two transponders, particularly insituations where governmental regulations stipulate the use of an ISO transponder yet
the animal has already been implanted with an older, non-ISO transponder (e.g.,animals relocating with their owners from the United States to Europe). In an effort todocument the occurrence and provide assurances of animal identification to authorities
in these situations, the WSAVA has worked in conjunction with the ISO committee
overseeing the global standardization of microchip technology (WG3). The result is arecommended protocol for identifying and documenting these occurrence with the form
provided in a pdf from the WSAVA website Microchip page.

We encourage WSAVA members that suspect a failed transponder in an animal to fillout the Failed Transponder Reporting Form and return it to the WSAVA for reporting
purposes.
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Recall of '999' microchips (letter)
Simon Swift
Chairman
BSAVA Microchip Advisory Group,
British Small Animal Veterinary Association
Kingsley House, Church Lane
Shurdington, Cheltenham
Gloucestershire GL5 5TQ
The Veterinary Record, October 2, 1999 408
SIR, - With increased awareness of microchip identification among the general public,
the announcement of the Pet Travel Scheme (PETS) and the introduction of compulsory
thoroughbred identification, more and more animals are being implanted withidentification microchips. In the ISO standard identification microchip, the first three digitsof the number represent a code that identifies the manufacturer of the device. This helps
to ensure the uniqueness of the rest of the identification number and helps to trace themanufacturer of any microchip that causes an adverse reaction.
Before being allocated an identification code, manufacturers must submit their products
to testing by an independent body to be sure that they meet the requirements of the ISO
standard. Such test microchips bear a code '999' as their first three digits and do notnormally reach the general circulation. Recently '999' microchips have appeared on themarket in the UK. This raises concern on two fronts. First, the code does not identify any
particular manufacturer and if there was a need to trace the source of a microchip, thiscould cause difficulty. Secondly, if more than one manufacturer released '999' test
microchips for sale, it is possible that the identification number could be duplicated.
Pet ID, the distributor of the '999' microchips, has now agreed to address this issue by
ensuring that all microchips supplied after the beginning of October, 1999 carry a proper
manufacturer code of '967' and by exchanging any of the '999' coded microchips still
unused after October 4.

All '999' numbers are carried on the Petlog database. Pet ID will also supply a complete
list of all '999' coded microchips that they have distributed in the UK to help ensure theirtraceability.
Could I, therefore, ask that practices check the numbers of any microchips on their
shelves and return any starting with '999' to their suppliers for replacement. Any
microchips which start with other three-digit codes are obviously unaffected.
Lastly, I would like to thank the manufacturer concerned for acting so quickly andcooperatively in addressing this problem.
Any questions concerning the above should be addressed to P'et ID, directly (telephone01444 441060).
__________________________________________Editor's note:
Since the above letter appeared, "999" Microchips have been identified in Australia andsome European countries, although WSAVA Microchip Committee actions in concert
with the ISO WG3 committee have since halted the distribuiton of "999" chips. However,readers are asked to notify the WSAVA microchip committee if this microchip
identification code is found in their country.
Contact:
Fred Nind, chairman, WSAVA microchip Committee