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 Zoonosis refers to diseases that can be passed from animals to humans. Most diseases are species specific, however some can cross between species. For example: you can't catch cat flu or cat AIDS as these diseases are specific to cat species only. You can however catch ringworm from a cat.
Zoonotic diseases are infectious diseases that are caused by bacteria, viruses and parasites. There are different methods of transmission including - direct contact, spread via contaminated water, spread through contaminated food, spread by insects. Prevention and control of these diseases are outlined below.
1. Dog/cat bite wounds -The most common zoonosis in Australia is bacterial infection caused by dog or cat bite wounds. Dogs and cats carry large numbers of bacteria in their mouths which can cause painful and sometimes serious infections. When dogs and cats bite, their teeth puncture our skin and inject these nasty bacteria into the deeper layers of our skin. This results in pain, inflammation and swelling. Any wound that punctures the skin should be seen by a doctor.
2. Fleas and tapeworm -Fleas are small wingless insects that feed on the blood of dogs and cats. They can also feed on the blood of humans! Fleas live in the environment ; carpets, bedding, between floorboards, in dirt patches, the gardens etc. The adult fleas hop onto dogs and cats for a blood meal. The female flea can then lay her eggs. These eggs fall off the pet and into the environment where they go through a number of changes before emerging as adults. As an adult flea can lay up to 50 eggs per day, flea populations can quickly and easily get out of control in the average household. When flea numbers reach 200 and greater, they start to look for other hosts including humans!
Flea bites in humans are intensely itchy and look like small mosquito bites. Some people may be hypersensitive to flea saliva and these people get much more severe reactions.
More seriously though, fleas can transmit tapeworm to humans! Fleas acquire tapeworm as larvae. The tapeworm survives in the flea until the flea reaches adulthood. Tapeworm is then transmitted to humans when/if an adult flea is accidentally eaten (think about how easy it is to swallow a fly - fleas are much smaller!!). This commonly occurs in babies who are closer to the ground. The tapeworm then develops in the babies intestines and causes diarrhoea, abdominal pain and itchiness around the bottom.
The best way to ensure your family is safe from fleas and tapeworm is to ensure your pet is on strict worming and flea control regimes. If you are not sure of your pet is protected, please contact the clinic.
3. Roundworm - Roundworms (Toxocara canis and cati) are dog and cat intestinal worms that can be easily transmitted to children. Children inadvertently come into contact with worm eggs via dog and cat faeces. This sounds disgusting but can happen very easily. Worm eggs are shed in the faeces. Faecal matter and therefore eggs can remain on your pets coat and children can come into contact through kissing the pet and or patting the pet and then putting their hands in their mouths. Children can also come into contact with eggs by playing in outdoor sandpits that the cat defecates in.
If a child ingests a worm egg, the egg then hatches in the child's intestine and the worm larva migrates through the body. This migration can cause lesions in various organs (visceral larval migrans). In a worst case the larva can go to the artery that supplies the blood to the retina of the eye causing temporary but sometimes permanent blindness (ocular larval migrans).
Prevention of transmission is two fold: 1) ensure good hygiene and commonsense 2) ensure your pet is on a strict worming regime.
Ensure that any outdoor sandpits are covered when not in use, ensure that children wash their hands thoroughly after playing with the dog, do not encourage kissing the dog on the mouth/face, ensure that any outdoor toys that become soiled are washed thoroughly with warm water and a disinfectant, ensure that gloves are always worn when gardening.
Please contact the clinic if you are not sure about your pets worming regime. We will be happy to help you ensure that your pet is worm free!
4. Ringworm - ringworm is a generic term for a fungal infection that may be passed between dogs, cats, and humans (it can affect cows and horses too!). Children can transmit ringworm to one another at school. There are 3 main species of fungi that cause lesions in dogs, cats and humans. Ringworm is highly infectious and the fungal spores can live in the environment for years. The lesions on your pet may appear as - areas of fur loss in a patchy or round shape and/or areas of scaly skin. Animals tend NOT to be itchy. The lesions on humans appear red, raised and often round. They are intensely itchy. If you suspect your child has ringworm, please see a doctor and ensure you bring your pets in to us for a checkup too.
5. Toxoplasmosis - Toxoplasma is a protozoal parasite of cats. Most cats become infected with Toxoplasma by eating birds, mice and raw meat (infected beef/lamb). Cats then shed oocysts (eggs) in their faeces. Humans can come into contact with toxoplasma through - emptying litter trays, contacting cat faeces in the dirt and eating raw meat.
In humans, toxoplasmosis causes fever, enlarged lymph nodes, muscle pain and a sore throat. Symptoms similar to most colds and viruses! Toxoplasma infection is most serious in pregnant women as it can cause abortion, congenital malformations and retardation. Most doctors will test pregnant women to see if they have immunity to Toxoplasma.
Ideally women should follow the following guidelines to reduce the chance of infection whilst pregnant;
- Eat only well cooked meat,
- Clean litter trays more regularly ie 1-2 times daily (the eggs need to sit in faeces exposed to air for 24-48 hours before they become infective).
- Ensure that you wear gloves when gardening,
- Stop feeding the cat raw meat,
- Keep the cat indoors to prevent him from killing birds and mice.
There should be no need to remove the cat from the household.
For further information and advice please contact your doctor.
6. Hydatids - Hydatids are small tapeworms. These tapeworms are a parasite of dogs however unfortunately, sheep and humans can also get infected. Dogs shed eggs in their faeces. If these are ingested by another dog, they hatch and mature into adult tapeworms. If these eggs are ingested by a sheep or a human, they hatch, enter the bloodstream and migrate through the body. They eventually come to rest in various organs (usually the liver), where they form cysts. Cysts can range in size from a golf ball up to a basketball! The problems caused in humans depends on where the cyst forms and how big it is. Sounds scary!
Hydatid tapeworm infection can be prevented by 1) good hygiene and 2) ensuring that your dog is wormed for tapeworm.
Ensure that you wash your hands thoroughly after playing with the dog, do not encourage kissing the dog on the mouth/face and ensure that gloves are always worn when gardening. It is also important to note that dogs may become infected by eating raw lamb offal (if that lamb has cysts). It is best to limit feeding of raw offal.
And finally, please contact the clinic to ensure that your dog is covered for tapeworm.
7. Sarcoptic Mange - Sarcoptic mange is caused by a microscopic mite which burrows into the skin of dogs and causes intense itchness. The itchyness is often around the face, ears, elbows, legs, tail and under the belly. The mite is carried by foxes, koalas, wombats and ringtail possums and it is through contact with these animials, or where they have been, that dogs contract the mite.
There is a significant infected fox population in the Rowville area.
Diagnosis of sarcoptic mange can be tricky in dogs as a mere 5 microscopic mites can cause the disease. Once diagnosed, treatment is rapidly effective.
The mite is transferable to humans, causing very itchy, red dots to appear usually on the arms, legs or chest.
Some figures report that up to 50% of owners of infected dogs will also show signs of infection but this is not our experience. It is RARE for us to see this disease spread to humans. In humans, the disease resolves of its own accord within 7-10 days.
We currently see 1-2 cases of sarcoptic mange in our clinic each month, but the incedence of the disease is currently on the increase in Australia.
8. Psittacosis - Psittacosis is bacterial infection in birds (Chlamydia psittaci). It can affect wild birds, poultry and domestic birds including parrots, canaries and budgies. Some birds that become infected become very sick but others can carry the bacteria and shed it with no apparent illness. Psittacosis causes flu-like symptoms in humans and can be very debilitating.
Humans are at risk of catching the bacteria by breathing in the dust of dried faecal matter and feathers/dander. Therefore to prevent infection, bird cages should be kept as clean as possible ie can use newspaper for the flooring and replace this daily! Birds should also NOT be kept in bedrooms, rather they should be kept in open areas with lots of ventilation. If you are concerned about psittacosis, please contact the clinic or your GP.
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