Fading kitten syndrome (FKS) is heartbreaking for cat owners and rescuers who care for newborn kittens. For those that regularly attend cat births, it can be frustrating to helplessly watch some kittens inexplicably "fade" and die under the most attentive care. But, an extremely perceptive caregiver might be able to recognize the signs of FKS, increasing kittens' chances of survival.
What Is Fading Kitten Syndrome?
Fading kitten syndrome is not a disease, but rather a collection of signs that develop in neonatal (newborn) kittens and signify their rapidly declining health. Kitten mortality is highest during the first week of life, accounting for up to 90% of feline deaths. An estimated 16% of kittens die before weaning.
FKS has many underlying potential causes but, unfortunately, the first and only indication of this syndrome is the unexplained death of a very young kitten. Because of this, FKS has been compared to sudden infant death syndrome (SIDS) in human babies.
Symptoms of Fading Kitten Syndrome in Cats
There are some indications that a kitten may be at risk of developing fading kitten syndrome. People who rescue and foster pregnant cats and/or foster kittens should take time to learn to spot the signs of FKS as the offspring of stray and feral cats are particularly prone to this condition. The signs to watch for include:
Kittens that develop FKS are often the smallest of the litter. They have a low birth weight and are not as active as their litter-mates.
Healthy kittens nurse almost immediately after birth. A fading kitten is often not strong enough to grasp and suckle the mother cat's nipple. During the first 72 hours or so of nursing after birth, healthy kittens that are nursing well receive special milk called colostrum. This colostrum provides essential nutrients and antibodies. Colostrum gives the kitten passive immunity, allowing them to grow and thrive until they can receive vaccinations and stop nursing. If a kitten fails to nurse and needs to be bottle-fed it will not receive colostrum and is more likely to develop FKS.
Mother cats sense when there is a weak kitten and may abandon it in favor of her other kittens. This is an instinctual reaction designed to protect the healthier kittens.
Since newborns can't regulate their body temperature, they depend on their mom for warmth. Therefore, abandoned kittens or kittens that wander away from their mom, rapidly develop hypothermia. Hypothermic kittens are lethargic. Its mouth and gums will be a bluish shade rather than a healthy pink. This can rapidly be fatal unless human intervention occurs.
Causes of Fading Kitten Syndrome
While there is no definitive cause or set of causes underlying the development of FKS, there are factors that contribute to kittens' early deaths. These include:
- Disease or malnutrition of the mother cat during gestation: If this is the queen's first litter of the season, she may not have access to the amount of food required to grow healthy kittens. Depending on the environment, a queen can have up to five litters of kittens within a year. This is physically taxing on the female cat, causing malnourishment and illness. This combination does not bode well for late-season kittens, resulting in higher rates of stillbirth, congenital abnormalities, and kittens with FKS. This is why it's so imperative to take a suspected pregnant cat to the veterinarian for a prenatal check-up. Your vet will discuss your options and how to take care of a pregnant cat.
- Infectious diseases: There are a number of viral and bacterial infections that quickly affect an entire litter of kittens. Keep litters of stray or feral queens completely separate from your household cats. If possible, donate your time or money to local feral and rescue cat organizations that help spay and neuter stray cats.
- Neonatal isoerythrolysis: This occurs when the queen and kitten have different blood types. The kitten's red blood cells are destroyed by antibodies they receive from the mother cat's colostrum.
- Fleas and other parasites: When fleas bite, they ingest blood and secrete saliva, so an infestation on a newborn kitten can lead to severe anemia or transmit parasites, both of which are potentially fatal. Kittens are susceptible to other infectious agents including protozoal infections, intestinal parasites, and ticks.
Diagnosing Fading Kitten Syndrome in Cats
Diagnosing FKS is generally based on the observation of symptoms in a newborn kitten, including lethargy, lack of nursing, and/or difficulty breathing. A veterinarian may also test the kitten for any infections or parasites.
Prognosis for Cats with Fading Kitten Syndrome
The prognosis is guarded in cases of fading kitten syndrome. Most kittens with these symptoms die.
Treatment and Prevention
The vet will prescribe a course of action to treat any infection as well as prevent hypothermia, malnutrition, and dehydration.
Since FKS is a rather mysterious syndrome that often occurs in feral cats, there is no sure-fire way to prevent it. The best course of action is to treat the specific signs in an ailing kitten and hope for the best.
In the unfortunate event that the kitten does not survive, know that you did your best to help them and try to direct your attention to the mother cat and other kittens to make sure they are healthy and thriving.
Chastant-Maillard, S., Aggouni, C., Albaret, A., Fournier, A., Mila, H. Canine and Feline Colostrum. Reproduction in Domestic Animals, 52, Suppl 2, 148-152, 2017, doi:10.1111/rda.12830
Silvestre-Ferreira, Ana C, Pastor, Josep. Feline Neonatal Isoerythrolysis and the Importance of Feline Blood Types. Veterinary Medicine International, 2010,753726, 2010, doi:10.4061/2010/753726
Lappin, Michael, R. Update on Flea and Tick Associated Diseases of Cats. Veterinary Parasitology, 254,26-29, 2018, doi:10.1016/j.vetpar.2018.02.022
Common Cat Diseases and Health Problems. Purdue University Cooperative Extension Service.