2003 saw a marked increase in the number
of reports received through the Adverse Reaction Reporting Scheme.
It is significant that several reports were received from some
quite small practices while many larger practices filed no reports
at all. This suggests that there is an element of under reporting
which may be happening for a variety of reasons.
Members of the BSAVA
Microchip Advisory Group would encourage everyone to complete
forms whenever problems are identified with implanted microchips
in any species. My only plea is that the forms should be completed
as fully as possible so that we can get the maximum benefit from
your efforts. Blank forms can be obtained from the BSAVA website
or from the Practice Support secretariat at BSAVA headquarters.
Telephone number 01452 726707
The vast majority of
reports received in 2003 relate to dogs. A few reports were also
received for cats. It is known that microchips are implanted in
a wide range of species and the Group would be especially pleased
to receive reports of reactions in the less common species.
A few of the reports
received are classified as microchip failure when the reader being
used could not identify the presence of a microchip. To be sure
that this is a true microchip problem and not a fault of the reader,
operators are encouraged to check the function of the reader against
a second microchip. For facilities that do not hold a stock of
microchips, manufacturers following the BSAVA Code of Practice
for Microchip Distributors have agreed to provide a specimen microchip
for this purpose.
Attention is also drawn
to the fact that many animals in the UK and throughout Europe
still carry older type microchips – variously known as FDX-A,
FECAVA standard or Annex A technology microchips. ISO readers
will NOT identify these transponders unless they have the additional
functions required to activate them. Older type microchips can
be read by
· ISO standard readers with annex A functions
· Older readers compatible with the previous microchip
technology
All microchips supplied
since 2000 should be FDX-B ISO microchips which will be identified
by all ISO readers. Members presented with an animal implanted
last century should be aware of this limitation.
Additionally some microchips implanted abroad are of a type that
may not be read by any of the scanners used in the UK.
Adverse reaction reports received
Year |
<1998 |
1998 |
1999 |
2000 |
2001 |
2002 |
2003 |
Total |
Number |
14 |
29 |
41 |
75 |
21 |
15 |
49 |
244 |
All reports in 2003 came from the UK. Reports in mainland Europe
are now channelled to FECAVA. No data is available from other
countries.
Species affected
Species |
<1998 |
1998 |
1999 |
2000 |
2001 |
2002 |
2003 |
Total |
Dog |
11 |
29 |
33 |
54 |
18 |
13 |
39 |
193 |
Cat |
1 |
0 |
6 |
15 |
1 |
2 |
10 |
36 |
Unknown |
2 |
0 |
2 |
6 |
2 |
0 |
0 |
12 |
Migration remains the commonest problem
with the elbow and shoulder being the favourite locations of wayward
microchips. In one dog a microchip that migrated was removed and
replaced with another microchip from the same manufacturer. The
new microchip migrated along the same route as its predecessor.
The owner declined to have a third microchip implanted! The time
between a microchip being implanted and the new location being
identified can vary between a week and 10 years. It is surprising
how quickly some microchips migrate.
The RCVS recently updated its advise
on microchip implantation. The revised advice can be found on
the RCVS web site at www.rcvs.org.uk
It is important that the implanter
is properly trained how to perform the procedure correctly. All
companies following the Code of Practice provide training courses
in the use of their products.
Type of reaction:
| Reaction
|
Unknown |
Migration |
Infection |
Failure
|
Swelling
|
Loss
|
Removed |
| <1998 |
0 |
10 |
1 |
1 |
0 |
0 |
0 |
| 1998 |
0 |
24 |
2 |
1 |
1 |
1 |
0 |
| 1999 |
1 |
28 |
1 |
1 |
2 |
7 |
1 |
| 2000 |
1 |
33 |
2 |
4 |
1 |
34 |
0 |
| 2001 |
0 |
9 |
1 |
7 |
1 |
3 |
0 |
| 2002 |
0 |
7 |
1 |
1 |
2 |
2 |
0 |
| 2003 |
1 |
22 |
0 |
11 |
8 |
7 |
0 |
Total |
3 |
133 |
8 |
26 |
15 |
54 |
1 |
The distribution among manufacturers is listed below. The relative
risk is not calculable without knowing the relative share of the
market attributed to each manufacturer. Such information is commercially
sensitive and is not available to the Microchip Advisory Committee
membership.
Reactions divided among manufacturers:
Manufacture |
Unknown |
Avid |
Animalcare |
Datamars |
Bayer
|
PetID |
Indexel |
Destron |
<1998 |
3 |
9 |
1 |
0 |
0 |
0 |
0 |
0 |
1998 |
1 |
15 |
3 |
9 |
1 |
0 |
0 |
0 |
| 1999 |
1 |
12 |
10 |
0 |
18 |
0 |
0 |
0 |
2000 |
5 |
11 |
29 |
0 |
23 |
2 |
4 |
1 |
2001 |
1 |
0 |
7 |
0 |
11 |
0 |
1 |
1 |
2002 |
2 |
0 |
0 |
0 |
10 |
1 |
0 |
0 |
2003 |
9 |
7 |
10 |
5 |
14 |
4 |
0 |
4 |
Totals |
22 |
54 |
60 |
14 |
77 |
7 |
5 |
6 |
To differentiate between lost and failed
microchips, radiographs should be taken. The following radiographs
have been taken in association with the scheme. In all cases,
the relevant suppliers were very helpful.
Year |
1998 |
1999 |
2000 |
2001 |
2002 |
2003 |
Number |
3 |
2 |
7 |
3 |
0 |
8 |
Finally the members of the BSAVA Microchip
Advisory Group would like to thank everyone who sent in adverse
reaction reports. Without your help we could not produce any data
at all.
Fred Nind September 2004
Chairman, Microchip Advisory Group
http://www.bsava.com/searchresults/?keywords=microchip
|