Although you might think this a strange topic for a veterinary web site (!), generally speaking you will be pleased to know that keeping pets is not a very risky business! However, as I am sure most people are aware, animals can inflict injury and they can suffer from diseases - some of these (called zoonotic diseases) can, potentially, be passed to humans and, in some cases, vice versa. Certain groups of people - usually those who have impaired immune systems (and are therefore less able to shrug off infection) - may be more at risk from such diseases - but the good news is that, even when an individuals health status changes (eg becoming pregnant or developing diabetes), taking sensible additional precautions usually means "You do not have to give up your pet".

The aim of this overview is to help you understand what these risks might be and put them into everyday perspective.

Accident or injury - pets may occasionally bite or scratch - the injury itself may require attention and infection secondary to the wound may also need treatment. These are not normally serious. Certainly, we as veterinary surgeons and nurses are well aware of the swollen, infected cat bite infection inflicted by a less than enthusiastic patient... but we still have all our fingers! However, awareness can help us to understand and avoid risky situations - we know that a frightened dog, for example, is capable of inflicting serious injury through biting - fortunately, this is not a common event - any pet exhibiting this kind of behaviour would be in need of help, probably from a qualified behaviourist who is experienced in assisting with psychological problems.

Zoonotic diseases that can be associated with pets -

• Salmonella, Campylobacter, Cryptosporidium and Giardia - Salmonella and Campylobacter present one of the highest risks of infection - these are usually associated with diarrhoea and particularly in connection with a young pet with diarrhoea which may have continued despite a course of antibiotics. However, having said this, 'food poisoning' is by far the most usual way for these 'bugs' to cause disease in humans - from contaminated food or water. Cryptosporidium and Giardia, similarly, can be picked up from a pet or from the environment.

• Roundworms (Toxocara) - from dogs and cats - these are widespread in the outside environment, particularly parks, sandboxes and beaches. The significance in the human is that the infective larval stage of the worm can be picked up from contaminated ground (not directly from faeces) - this can then migrate within the body and can lead to blindness following damage to the eye - so called visceral larva migrans. Toddlers who are at the stage when everything they pick up goes straight into their mouths are most at risk of catching this. This is now, thankfully, a rare condition — however, we, as vets, and all dog and cat owners have a public duty to ensure that our pets are wormed regularly and effectively, and that we clean up thoroughly after them particularly in public places to reduce the overall risk as best we can.

• Toxoplasmosis - a widespread organism, carried by most warm-blooded animals. Most human infection is either mild or without symptoms -immunocompromised people and the unborn child may be at increased risk -although studies have failed to link this with keeping (or being in contact with) cats, regular hunters (who eat mice, voles, etc) may carry the organism, stray cats being more likely to be carriers than pets.

Simple handly cleanliness and food hygiene reduce any risks to a minimum for most people. Additional advice, particularly for pregnant mothers and immunocompromised individuals would include minimising or avoiding direct contact with cat litter trays and cat faeces, wearing gardening gloves and making sure childrens' sand boxes/pits are covered when not in use.

• Cat Scratch Disease (CSD - Bartonella organisms)

• Ringworm - quite common fungal skin infection - cats, horses, cattle and humans amongst the commonest species affected although many others possible. In contact animals and humans in household should be screened and treated under the direction of the general practitioner and/or veterinary surgeon.

• Rabies This is not an exhaustive list of all the 'bugs' in the world that may have a link between pets and people but does represent the most likely possibilities here in the UK at the present time.

Immunocompromised Pet Owners - I mentioned earlier that certain groups of people may be more 'open' to zoonotic infections - here is a list of those that are potentially more at risk:

• Infants and children less than 5 years old
• Pregnant women
• Diabetics
• People with immune-mediated disease, eg SLE, who are on
immunosuppressive drugs
• People who have had their spleen removed
• Cancer patients undergoing chemotherapy or radiotherapy
• Transplant recipients who are on anti-rejection drugs
• People infected with HIV or affected by AIDS

How Veterinarians can help -
• We can provide information concerning veterinary and public health aspects of zoonoses to pet owners
• We cannot diagnose, treat or make recommendations about disease in humans but should refer owners to their physician for further guidance
• We can give additional advice to owners with special circumstances (ie if at increased risk - see above) regarding additional measures relating to pet ownership so that individuals can make informed decisions about keeping or acquiring pets. Remember... "You do not have to give up your pet".

Offer an Expanded Zoonotic Disease Control and Prevention Programme - as well as the usual advice, when acquiring a new puppy or kitten, to ensure that he or she is from a reputable source, and that your new pet is checked and treated for worms, fleas, ticks, etc we would recommend certain additional measures for any 'at risk' owner:
a period of quarantine for a new or clinically ill pet
- increased regular hygiene measures
- a routine check up and faecal screen every 6 months
- preventive medicine including de-worming and flea/tick control (which is routine but becomes even more important under such circumstances)

If you have any health concerns which relate to acquiring a new pet or keeping an already much-loved one please feel welcome to seek our advice.

For further reading and information please refer to the following sources

• www.cdc.gov/healthypets/index.htm
• www.deltasociety.org
• Centers for Disease Control and Prevention
• National Center for Infectious Diseases
• Healthy Pets for Healthy People