Zoonotic diseases are diseases or ill health caused by the transmission of bacteria, protazoa, fungi and parasites from animal to human. The ones I will be writing about are not only local to Australia but I specifically researched the common ones present here in Australia. Some you may

of heard of, others you may not of but if you own a pet such as cat, dog, bird or reptile you and your family may be at risk of contracting one of these diseases.

Bacterial zoonosis.

• Cat scratch fever: This is an infection caused by Bartonella Henselae. About 40% of cats will carry this bacteria in their saliva in their life and is more common in kittens than older cats. Cats carrying this, don't usually show any clinical signs and may be in very good health otherwise. It is carried in the saliva and usually infection occurs after a cat scratch or bite, all though it can be carried on the fur (cats clean themselves with their tongues!!!!) and transmission can occur by rubbing your eyes after petting your cat. In otherwise healthy people this is rarely fatal and a small nodule (raised lump) at the site of entry within 10 days of the injury occuring. Symptoms that may follow include fever, chills, nausea, vomiting, fatigue and inflamed lymph nodes. More nodules under the skin may occur, but usually this infection will resolve itself with out medical attention. If the lymph nodes remain swollen for an ongoing period of time, antibiotics can be prescribed by a GP usually until the nodules have gone which usually happens in 3 -4 weeks. For those with weakened immune systems, such as those with HIV/AIDS it can cause an abnormal growth of vessels which leads to inflammation of organs such as the liver, spleen, lungs, brain and bone marrow. Left untreated it will be fatal. To prevent being infected, avoid situations where you may be bitten or scratched, wash your hands after handling your cat and as it is believed the cats contract the bacteria through flea bites, flea control is believed to be beneficial in the avoidance of cat scratch fever. If you have been bitten or scratched by a cat and start showing any of these symptoms it is reccomended that you see you GP immediately.

 

• Listeriosis: Also known as listeria is caused by the bacterium listeria monocytogenes. Those most at risk are pregnant women (particularly in the last trimester), newborns, and kids and those with weakened immune systems. People who have also recently recieved an organ transplant are at an increased risk. it is transmitted through unpasturised dairy products, processed meats, undercooked meats, shellfish, coleslaw made from contaminated cabbage, soil and water, although once contracted it usually has no identifiable source. Symptoms include fever, vomiting, diahorrea, difficulty breathing, lethargy and poor feeding in new borns and young children and inappetance in adults. In pregnant women only mild flu like symptoms will present and you may be at risk of premature delivery, miscarriage or stillbirth. For those with weakened immune systems more serious complications such as pneumonia. meningitis and sepsis can occur. treatment is usually a course of IV (intra veinous) antibiotics over a 10 day period which may vary depending on each individuals immune response. The sooner it is detected and treated the better, all though prevention is better than cure, there is no vaccine available as yet and precautions can be taken to avoid being infected. These include safe foodhandling procedures, cooking meat thoroughly and avoiding the above mentioned foods if you are in a high risk catergory. Contact your doctor immediately if you show these symptoms and believe you may have eaten something which could possibly have been contaminated.

 

• Salmonellosis:  Caused by the salmonella bacteria, which is carried by some animals such as turtlles and lizards and is transmitted through the feaces of the animal. It can also be transmitted through undercooked or raw meats and eggs and it may also be present in water or soil. Handwashing and proper foodhandling procedures are the best way to avoid getting salmonella along with not owning reptiles with young children. Those most at risk of getting salmonella are children under 4y/o who account for 1/3 of reported infections in Amercia. The most common type of salmonella associated with humans is nonthyphoidal salmonella and is carried by chickens, cows and reptiles. Symptoms include  nausea, vomiting, diahorrea (sometimes bloody), fever  and headache. The other source of salmonella also known as thyphoidal salmonella which only humans carry is alot rarer and is usually contracted through direct handling of feaces from an infected persons. This usually occurs in third world countries where appropriate systems for handling human waste are not present. This form is usually more severe in its symptoms which include high fever, abdominal pain, headache, lethargy, constipation and skin rash. In nonthyphoidal salmonella, symptoms usually present in 3 days and require no medical treatment. In the case of thyphoidal salmonella symptoms are the same but the spleen and liver can become enlarged and the infected person will present with a rose spotted rash and it can lead to more severe complications such as menengtitis and pneumonia. For those in a higher risk group (weakened immune systems, sickle cell disease, nonfuctioning or absent spleen and those who take large quantities of medication for stomach acid) doctors will usually treat an infection with antibiotics. A doctors visit is always reccomended especially if your young child is showing any of the above symptoms. Your doctor may let it pass its course or prescribe panadol (or other fever and pain reducing medication) and/or antibiotics if it has gone on for more than 3 days.

Protazoan zoonosis.

• Toxoplasmosis: Caused by the parasite Toxoplasma gondii, toxoplasmosis is usually transmitted through cat feaces or eating undercooked/raw meat, particularly pork, lamb or venison. Symptoms are similar to that of the flu, fever, chills, muscle aches and pains and usually last from a few days to a few weeks. Normally people aren't even aware they have contracted the parasite and the good news for those of us with healthy immune responses, once you have had it, you can't get it again. Getting toxo for the first time during pregnancy usually has a devasting effect because the infection is passed from mother to baby and can cause serious defects in the unborn baby including mental retardation, cerebal palsey, deafness, microcephaly (unusually small head) or hydrocephalus (unusually large head due to pressure on the brain) and that is if miscarriage or stillbirth does not occur. Toxo can be tested for in the blood and is that refined you can be told if the infection was sometime ago or more recent. Prevention for those in high risk groups, such as pregnancy and/or weakened immune system include, wearing gloves when working outdoors or handling dirt, kitty litter and raw meats. Washing your hands with warm soapy water after each of these activities has also been proven to be very effective in the prevention of toxo. Above all else if it is possible have someone else do these activities for you. If you can't have someone handling your kitty litter tray, changing it daily will help reduce the risk of getting toxo because the parasite needs a few days to become infectious. Once a cat has toxo, it is only able to contaminate humans for a few weeks as after that the cats immune system does what ours does. For otherwise healthy, non pregnant people treatment is not needed, but is available to treat the parasite in pregnant women and those with weakened immune systems.

Parasitic zoonosis.

• Hydatid disease: This is a hard one to write about as it is a really complex cycle. It starts as adult tapeworm in dogs, then the eggs are passed in the feaces of an infected dog, they are then ingested where stomach acid causes the eggs to hatch in the small intestine and then penetrate the intestine and travel through the blood to other organs such as the liver, lungs brain and eyes (just a few examples). They then develop through expansion into a cyst where through asexual reproduction many tiny tapeworm heads form. Cysts can grow to a very massive size and eventually if left untreated can explode causing fatality. Symptoms vary so greatly depending on the size of cysts, location/ organs infected, and pressure put on surrounding structures. Risk factors include, porr hygiene of both human/animal, feeding of raw offal to dogs, allowing dogs to roam along with regular, close contact. Prevention of infection includes hygiene measures such as hand washing, not handling dog feaces, not allowing dogs to defeacate in the vicinity of high traffic areas, and a wormer for your dog which contains Praziquantel.

Fungal zoonosis.

• Ringworm: Ringworm is not caused by worms. It is a fungus which lives on the top layer of the skin and on the hair. It grows best in warm moist conditions and is very common. Symptoms is usually a red itchy rash in the shape of a ring (but not always ring shaped). It can affect anywhere on the body and is not specific to any particular groups. transmission is usually from pets to human or human to human contact and diagnosis can usually be done by veiwing a skin scraping under a microscope or with a blue light in a dark room where the fungus will illuminate. Treatment is not always necessary and with good self care usually clears up in around 4 weeks. Keeping the skin clean and dry, washing your sheets while infected on a daily basis, and an over the counter antifungal cream. severe or persistant infection may require treatmeant from a doctor who may prescribe stronger antifungal pills and/or creams. antibiotics may also be needed for related bacterial infections at the site of infection. Any pets will also need treatment to prevent re infection. You should seek medical attention if areas such as scalp or beard are ifected or if an infection has persisted for mour than 4 weeks. Prevention, once again is better than cure and good skin care such as cleanliness and dryness, not sharing personal items such as protective headgear, brushes, towels and clothing, avoiding animals with bald spots, shampooing regularly especially after haircuts, and wearing thongs or sandals at pools and showers.

These are only a few of the more common diseases that can infect humans from animals and if you have any concerns or believe you may have one of these conditions, I strongly reccomend a visit to the doctor if not for a confirmational diagnosis, your own peace of mind. With preventing the transmission of any of these, good personal hygiene is essential and should be followed any how. Hope this has been helpful to you all and please feel free to leave a comment below if you would like any further information, think I can improve this article or simply if you did find it helpful. Thanks for taking the time to read.