A vs B ... A Consideration
By Dr. Urs Giger
Submitted by Virginia Noblitt
June 1990 Newsletter
updated March 2012
How many of us have had a healthy litter and then, within a day or two have had
one die of no apparent cause? One possible cause could be an incompatibility between the
blood of the mother and that of the kitten.
Dr. Urs Giger of the University of Pennsylvania School of Veterinary Medicine,
Medical Genetics Section, has been heading a study of blood typing in cats. He has documented
two blood types -- type A, the most common and type B, occuring rarely. He has tested both
domestic shorthair cats and purebred cats. Reproduced here is an article whic appeared in the
July 1989 issue of Cat Fancier's Almanac, reprinted with Dr. Giger's permission.
Knowing your cat's blood type can help in preventing fading kitten syndrome and
transfusion reactions
Urs Giger, Dr. med. vet.FVH Diplomate, ACVIM, Assistant Professor of Meddicine
Blood types (groups) are genetic markers on red blood cells that are specific to
each species (cats, man, etc..). Like the Rhesus (RH) factor in humans, they may be of importance
to your cat's health or the health of their kittens.
More than one blood type has been known to exist in the cat for many years. Until
recently, however, very little was known reguarding the importance of these blood types and how
they are inherited. Our recent limited survey in the United States shows that nearly all domestic
shorthair cats have type A blood (the most common type). We have found only one domestic shorthair
with type B blood. However, we have identified many purebred cats with type B blood including
British shorthairs, Persians, Himalayans, Birmans, Abyssinians, Somalis, and Devon Rex. Some breeds
have not yet been studied. Cats with type B blood appear to have strong antibodies against
type A red blood cells. These anti-A antibodies, as they are called, can cause two serious
problems:
(1) Fading kitten syndrome: if a queen with type B blood is bred to a type
A tom and produces kittens of type A, these antibodies in the colostrum (first milk) of the
mother will cause distruction of red blood cells in the kittens. These kittens are born
healthy, and may have red-brown colored urine within hours of their first nursing. The kittens
do not thrive and may die within the first few days of life. This syndrome is called
neonatal isoerythrolysis and is a major cause of the fading kitten syndrome.
(2) Transfusion reactions: Cats with the relatively rare typ B blood
can die if given a transfusion with the common type A blood. This is the type of blood used
for transfusions in al cats at the major Veterinary Teaching Hospitals in the United States.
Our Survey showed that only a small number of these transfusion reactions have been documented,
but they can avoided by using the type B blood from the University of Pennsylvania Feline
Blood Bank, or the blood of another type B cat.
Both of these serious problems can avoided by a simple blood typing test. To
prevent the problem of fading kitten syndrome, the queen and the tom should be typed before
breeding in order in order to make sure that they are both of compatible blood type. (The blood
type does not change, so a cat only needs to be typed before any transfusion is given.)
The University of Pennsylvania now offers a blood-typing service to all breeders
and owners of cats. This service runs $40.00 per animal (check to the University of
Pennsylvania, Dr. Giger). Please check http://research.vet.upenn.edu/penngen
for current requirements and to learn about their online database https://netapps.vet.upenn.edu/PennGen/SampleTesting/default.aspx
where breeders/owners and vets have to create an account(free) for themselves and login into that account
to fill in the animal information and select the test and sample type. Once they do all that their sample gets a
submission ID allotted to it and then they should print it out and send it along with their sample.
To submit a sample of your cat's blood, have your veterinarian take a small
sample (1 to 2 cc) of blood into a "purple-topped" test tube. Have the veterinarian label
the tube with the cat's name, and include with the tube the age, breed, sex, a copy of the
cat's pedigree, and any history of problems with transfusions or fading kittens. Wrap the
tube in paper towels and put into a shipping container with ice or ice pack. Do not allow
the tubes to directly contact the ice. Ship overnight mail service to:
Dr. Urs Giger
Department of Clinical Studies, Veterinary Hospital
University of Pennsylvania
3850 Spruce Street
Philadelphia, PA 19104-6010
Phone: 215-898-8076
During the course of Dr. Giger's study, it was discovered that a type B
queen bred to a type A male can produce kittens having type A and kittens having type B
blood. Before the geneticists among us protest that this is not genetically possible, let
me explain that there is no test at prestent for a typ A cat who carries type B. A type A cat
that carries type B will test as a type A. Therefore, a type B queen and type A male mating
can produce a type B kitten.
While the adverse reaction between the blood types is known, it does not always
occur. There are instances of a type B queen bred to a type A male and having a type A kitten
without problems occurring, but this is the exception rather than the rule. Those of us who
breed Somalis, especially those of us who plan to use outcrosses in our breeding progams,
should consider blood typing. And we should all have our cats blood type before any transfusion is
needed.