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Zoonotic Diseases
Zoonoses are those diseases of animals which are naturally
transmissible to humans. The number of zoonoses known to occur
naturally in New Zealand are comparatively few, less than
30. There are over 150 zoonoses recorded throughout the world.
While these diseases may seem to be serious, it is important
to keep them in perspective. The advantages of pet ownership
far outweigh the risks of these diseases. Do any of you smoke?
Campylobacteriosis
Causative Agent
Bacteria belonging to the group Campylobacter.
Occurrence in Animals
A common unapparent infection in poultry, and wildlife (seagulls
are commonly infected). Also occurs in dogs and cats.
Disease in Animals
Usually an unapparent infection. May cause diarrhoea in dogs
and cats, especially kittens and puppies.
Features of Transmission
Infection is usually by the oral route and contact with infected
faeces. Infective dose is low.
Disease in Humans
Enteritis causing diarrhoea and abdominal pain. Severe in
immuno-compromised individuals.
Diagnosis
Isolation and culture of the organism in faeces.
Treatment
Most cases are self limiting. May require antibiotics.
Leptospirosis
Causative Agent
Bacteria belonging to the group Leptospira interrogans.
Occurrence in Animals
Infection is common in possums, rats, mice, and hedgehogs.
Different types affect different species of rats.
Disease in Animals
Usually no signs of disease.
Dogs develop serious kidney disease.
Features of Transmission
Urine from infected animals is the mode of transmission. Infection
is gained through the skin or mucous membranes.
Infection is common in adult animals and is usually present
for life. Wild rodents are a potential source of infection.
Infection from possums is unlikely.
Disease in Humans
Initially the disease produces flu like symptoms. This may
develop into abdominal pain, vomiting, and meningitis.
Diagnosis
Blood tests.
Treatment
Pain relief, rehydration, and antibiotics if caught early
enough.
Ornithosis
Causative Agent
Avian strains of Chlamydia psittaci.
Occurrence in Animals
The organism is found in wild and cage birds, especially the
parrots.
Disease in Animals
Usually enteritis, liver and spleen disorders. Respiratory
disease, conjunctivitis, diarrhoea.
Features of Transmission
The disease is rare in cage birds in New Zealand. Not much
information exists about the disease in wild birds.
Disease in Humans
Flu like symptoms, pneumonia, liver and spleen disease.
Diagnosis
Blood tests.
Treatment
Antibiotics.
Pasteurellosis
Causative Agent
Bacteria of the class Pasturella.
Occurrence in Animals
A common inhabitant of the respiratory system of cats, dogs
and rodents. Common in the mouth of cats and dogs.
Disease in Animals
Common cause of respiratory and skin disease of rabbits.
Features of Transmission
Commonly associated with cat bite abscesses, and stress related
diseases in intensively housed animals.
Dog and cat bites
Disease in Humans
Most common form is a local infection and lymph node infection
due to a bite. can be associated with respiratory infections.
Pasteurellosis contd
Diagnosis
Bacterial isolation.
Treatment
Antibiotics.
Salmonellosis
Causative Agent
Bacteria from a large group of Salmonella.
Occurrence in Animals
Common organisms in most animal species. Occurs in seagulls,
broiler chickens, reptiles, particularly turtles.
Disease in Animals
Usually no signs of disease.
Features of Transmission
Faecal spread. The entire turtle tank.
Disease in Humans
Infection via oral route. Gastroenteritis.
Diagnosis
Bacterial culture
Treatment
Self limiting. Antibiotics.
Tuberculosis
Causative Agent
Mycobacterium tuberculosis, M bovis, M avium.
Occurrence in Animals
Cattle and possums.
Disease in Animals
Draining skin wounds.
Features of Transmission
Spread by contact with pus. Oral and respiratory routes.
Disease in Humans
Very rare. Respiratory disease, lymph node infections, and
abscesses.
Diagnosis
Culture and blood tests.
Treatment
Very long antibiotic treatment.
Ringworm
Causative Agent
Fungi, Microsporum canis, Trichophyton erinacei.
Occurrence in Animals
Common in kittens, puppies. Very common in hedgehogs.
Disease in Animals
Crusty lesions, hair loss. Can have no symptoms.
Features of Transmission
Direct contact. Contaminated environment. Difficult to catch.
Disease in Humans
Local areas of inflammation. Hair loss.
Diagnosis
Microscopic exam. Culture.
Treatment
Antifungal drugs, oral & topical.
Toxoplasmosis
Causative Agent
A protozoal parasite called Toxoplasma gondii.
Occurrence in Animals
Very common in a wide variety of animals and birds. Especially
common in kittens.
Disease in Animals
Usually unapparent infection. Can cause abortion in sheep.
Features of Transmission
Eggs are very commonly found in environment, and can last
a long time. Infective cysts found most commonly in cat faeces
and raw mutton. Infection is gained orally. Kittens pass high
numbers of eggs in faeces.
Disease in Humans
“Humans are surrounded by a sea of toxoplasms”.
No correlation between cat ownership and infection. Pregnant
women most at risk group.
Don’t eat raw or undercooked mutton
Wear gloves when gardening, or handling cat faeces/litter
trays.
Don’t get a new kitten prior or at time of pregnancy.
Soil contamination is most likely source of infection.
Usual infection is self limiting and fever and lymph node
enlargement.
Pregnant women face the risk of foetal abnormalities.
Immunocompromised people can have severe infections.
Pregnant women working at SPCA.
Diagnosis
Blood tests
Treatment
Antibiotics.
Usually self limiting disease.
Visceral Larva Migrans
Causative Agent
Larval stage of Toxocara canis, T cati
Occurrence in Animals
Infection rates are very high in young animals. Puppies 100%.
Disease in Animals
Mostly subclinical.
Can produce vomiting, diarrhoea, pot belly, cough.
Features of Transmission
Egg passed out in animals faeces is the infective stage.
Regular worming of young animals easily kills the worms.
Route of infection is by oral route.
Eggs can last a long time in environment.
Disease in Humans
• Disease related to migration of larva through body
tissues causing inflammation
• Eye disease in children resembles a cancer
• Can affect brain and heart
• Usual infection is self limiting and fever and lymph
node enlargement
• Pregnant women face the risk of foetal abnormalities
• Immunocompromised people can have sever infections
Diagnosis
Blood tests.
Treatment
Usually self limiting disease.
Some drugs.
Hydatids
Causative Agent
Hydatids cysts of Echinocccus granulosa.
Occurrence in Animals
Rare.
Mainly occurs on farms where dogs are fed wrong food or scavenge
dead animals.
Disease in Animals
No signs of infection in dogs.
Sheep have cysts.
Features of Transmission
Infection by direct or indirect contact with infected dogs,
and eating of eggs shed in faeces.
Easily treated with worm tablets in dogs.
Disease in Humans
Very rare. Cysts develop in tissues.
Diagnosis
X-ray, blood tests.
Treatment
Surgery
Fleas
Causative Agent
Ctenocephalides canis, C. felis, various bird fleas
Occurrence in Animals
Most common ectoparasite in dogs and cats.
Disease in Animals
Skin irritation and hair loss.
Features of Transmission
Require close contact with infected animals or contaminated
environment.
Life cycle 4 stages, occur on animals and environment.
Easily treated in animals.
Disease in Humans
Skin irritations.
Allergic individuals.
Diagnosis
Lesions. History of contact.
Treatment
Insecticides on animals and environment.
Mites/Lice
Causative Agent
Various species especially from cats and birds.
Sarcoptes, Cheyletiella
Occurrence in Animals
Rare.
Seen occasionally on sick/debilitated cats.
Common on seabirds.
Disease in Animals
Skin irritation
Features of Transmission
Direct contact.
Self limiting.
Disease in Humans
Skin irritation.
Mites/Lice contd
Diagnosis
History. Direct observation.
Treatment
Insecticides.
Cat Scratch Disease
Causative Agent
Unknown agent.
Occurrence in Animals
No clinical disease seen in animals.
Disease in Animals
No clinical disease seen in animals.
Features of Transmission
Transmission by scratches and bites from cats.
Disease in Humans
Common in children.
Initial skin lesion at site of trauma. Then lymph node enlargement,
fever, malaise develops for days to weeks.
Diagnosis
History and signs.
Treatment
No specific treatment. Antibiotics used.
Summary
• wash hands after handling animals, wastes, rubbish,
before eating
• wear gloves when handling body wastes
• don’t eat and work at same time
• wear protective clothing
• immunocompromised people - diabetics, immunosuppressive
drugs, AIDS
• pregnant women
• don’t smoke and work at same time
• report any injuries, including scratches and bites
• report any abnormalities in animals
• if in doubt ask the supervisor
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