Certain bacteria commonly found in dogs and cats are harmless to your pet's health, but may be deadly to humans.
A one-year-old toddler from Paarl almost died after being scratched by a cat. In this rare case, a micro-organism that occurs naturally in the saliva of cats and dogs, almost claimed his life. Cats and dogs can indeed infect humans with strange and dangerous diseases, but this is rare.
Doctors from Tygerberg Hospital in Cape Town managed to save this toddler after a battle lasting six weeks. They are of the opinion that little John-Lee Owies is possibly one of the first South Africans who developed life-threatening lung- and kidney complications after the bacterium Pasteurella multocida penetrated his body through the scratch mark.
The micro-organism Pasteurella multocida is found in the saliva of approximately 66% of dogs and 70% of cats. Cats and dogs are not affected by this micro-organism themselves. It is also found in cattle, poultry (it is known as avian cholera), rodents, rabbits and pigs, but in these animals can lead to symptoms ranging from sniffing, to bleeding to abscesses.
Transmission by scratches, bites and licks
This organism can be transmitted when a cat or a dog bites, scratches or licks a person. It can also be transmitted without the person even remembering that he/she had contact with cats, dogs or other animals, medical journals say.
Cats and dogs can also transmit other organisms. And yet, only 5% of all dog bites and 30% of cat bites result in an infection or an infection-related complications. Only in rare cases, does contact with P. multocida lead to a life-threatening complication, as in John-Lee's case.
Pasteurella multocida is a gram-negative coccobacillus bacteria. It does not form spores. It is part of the normal mouth flora of dogs (66% incidence), cats (70% incidence), and other domestic species, including birds, cattle, pigs, rodents and rabbits. Synonyms for this are Bacterium mutocodoium and Micrococcus gallicidus, to give the correct technical terms.
How can you recognise the disease in humans?
The first signs will develop at the wound site, 12 to 72 hours after the bite or scratch. In children the first symptoms can easily be confused with those of other serious diseases such as Haemophilus influenzae. However, if the child has had exposure to a cat or a dog, the doctor should be alerted. John Lee was indeed scratched by a cat. According to his mother, Johanna Owies, he liked to try and grab stray cats by their tails and try to bury their heads in the sand.
The first indications can be swelling and infection around the wound site, as well as red lines on the skin alongside the wound. The bacterium can also form abscesses in the lungs and also cause other serious lung complications. It can also affect the heart, the brain (brain infection and meningitis), the kidneys and the eyes. Inflammation in the skeletal bones and the tendons (especially after cat bites), which can be extremely painful, can follow.
Can this be treated?
It is, of course, best to prevent being bitten, scratched or licked by your cat or your dog. People who wait eight to ten hours after being bitten or scratched before they seek medical help, have a far greater chance of being infected. People with diabetes, HIV infection or any other immune-compromising condition, or liver disease, have an increased chance of becoming infected.
If a dog or cat has bitten or scratched you, the wound site should preferably be cleaned well immediately with an antibacterial fluid and lots of very clean, lukewarm water. The wound should then be treated by a doctor. Injections against tetanus and rabies are strongly recommended in all cases of animal bites.
Doctors in Chicago recently made a breakthrough in managing to save the life of a girl who was suffering from advanced rabies. But, in spite of this, it is much wiser to do everything in one's power to prevent the disease. The first symptoms of rabies appear between 20 and 60 days after a biting incident.
Other diseases which can be transmitted from cats and dogs to humans
Parasitic diseases, of which toxoplasmosis – which can only be caused by cats – is by far the worst. People who have cat litter trays in their houses, can get this. If a pregnant woman is infected by this parasite, her unborn baby could die, or the baby can be born blind or mentally handicapped. Other parasitic diseases that are spread by dogs and cats, include Giardia and Cryptosporidium, which can cause diarrhoea in humans. Then there are also ringworm and roundworm infections.
Bacterial or viral diseases include rabies, which can only be prevented if the person who has been bitten, is immediately vaccinated. Cat scratch disease or bartonellosis is caused by a bacterium known as Bartonella henselae and is transmitted by cats. It causes swollen glands, headaches and fever, which usually disappear after two to five months. Bacteria with names such as Salmonella, or Campylobacter, which can lead to bloody diarrhoea and can also be fatal, are also transmitted by dogs and cats.
Preventing diseases from your pets
You certainly do not have to have your pet put down. Take proper precautions.
Never handle your dog's faeces without gloves. Also do not work in the garden without wearing garden gloves, since all sorts or organisms can lurk in the animal faeces and the garden soil.
Always wash your hands after touching your dog, whether you touched its face, its body or its head. Teach your children to do the same.
Also teach your children never to eat sand or soil and cover your sandpit with a solid cover.
Teach your children not to play too roughly with animals.
De-worm your dogs regularly.
Vaccinate your dog against rabies.
- Last updated: June 2010