British Small Animal Veterinary Association
Importance of understanding zoonoses
More than 200 companies contributed to the exhibition held in association
with the BSAVA congress |
The prevention of zoonoses — diseases contracted from animals — requires
an understanding of the biology of the pathogens as well as common sense
measures such as hand washing and proper disposal of animal waste, said
Alan Radford, of the University of Liverpool Small Animal Teaching Hospital,
in an update lecture on zoonotic infections.
Prompt diagnosis and treatment
of the infected animals are also vital. Dr Radford said that zoonotic
infections range from common to rare and involve all the important
pathogen groups. Many are mild and have only temporary effects but others
can
be fatal. Most can be severe in high risk populations such as the old,
the young and the immunocompromised.
Briefly reviewing the more important and interesting zoonotic infections,
Dr Radford said that the classic small animal zoonosis is probably
rabies. Although rare in the UK it remains a common and terrifying
disease in
other areas of the world with between 40,000 and 70,000 deaths annually,
according to World Health Organization statistics.
A new viral zoonosis is avian influenza, which is known to have killed
more than 200 people. Less serious viral infections include cowpox
virus which has its reservoir in wild rodents but can cause skin lesions
in
humans and cats.
Turning to bacterial zoonoses, Dr Radford said that undercooked meat
(especially poultry), unpasteurised milk and untreated water are associated
with intestinal disease caused by campylobacter. Other examples of
bacterial zoonoses include Bordetella bronchiseptica, which causes
kennel cough
in dogs. Many cases have been reported of severe infections in immunocompromised
people.
Other agents of zoonotic infection include fungi (eg, ringworm), protozoa
(toxoplasmosis) and nematodes.
How to alleviate fear-induced aggression in dogs
The treatment of canine fear aggression was discussed by Gary Landsberg,
of North Toronto Animal Clinic, Ontario, Canada, who gave advice on behavioural
management and products.
Dr Landsberg told the audience that a dog’s response to a stimulus
is based on its genetics, socialisation and previous experience. How
the stimulus and owner respond might further reinforce or aggravate the
situation. Thus if aggression resulted in withdrawal of the stimulus
the behaviour has been negatively reinforced. On the other hand if the
stimulus retaliates or becomes worse then the pet fear will be further
conditioned.
The fear-inducing situation can be modified by placing more distance
between the stimulus and the dog, by changing the nature or intensity
of the stimulus, by changing the location of the interaction (eg, in
the open rather than in a constrained area) or by separating the stimulus
into component parts (eg, a visit to the vet may involve a car journey,
time in the waiting room with other animals, time in the surgery, etc)
and dealing with each in turn.
Dr Landsberg emphasised the importance of “reading” a dog’s
temperament before seeking permission from the owner to approach it.
This is even more important if no owner is present or the animal is off
a leash. Erect ears, staring eyes, yawning, licking of lips or snarling
are all signs that the animal may be likely to bite.
For guidance on how to avoid bites from dog, particularly in children,
Dr Landsberg recommended the websites
The Blue Dog (www.thebluedog.org)
Doggonesafe (www.doggonesafe.com)
The particular problems of pain control in cats
Dealing with feline pain presents particular problems, said Garry Stanway,
a vet from Cheshire, in a presentation on chemical restraint and the
analgesic approach in cats.
He emphasised that cats demonstrate pain differently from dogs by becoming
quiet and withdrawn, and hiding. Further, cats do not express pain, and
acquiescence should not be interpreted as comfort. They are also dangerous
and hard to control when scared.
Mr Stanway said that analgesics are used less frequently in cats than
in dogs because there is a perception that morphine causes a rage reaction
in cats, because cats cannot metabolise non-steroidal anti-inflammatory
drugs as well as dogs can and because cats’ small size leaves them
vulnerable to adverse reactions from local anaesthetics.
Concluding, Mr Stanway said that the measures that can be taken to promote
good analgesic practice include the use of pre-emptive analgesia and
the concurrent use of analgesics from different drug groups.
Troublesome ticks
Tick-borne diseases of dogs and cats were discussed in a presentation
by Janet Foley, of the University of California, Davis, School of
Veterinary Medicine. She said that ticks are major pests of dogs and,
to a lesser
extent, cats. They bite, feed on blood, cause local irritation and
transmit several serious diseases.
After piercing the skin with biting mouthparts they cement themselves
into the skin and secrete immunoactive chemicals to ensure an influx
of inflammatory cells and prevent clotting. Tick bites produce local
irritation and can predispose the bitten area to secondary bacterial
infection. |
The
Pharmaceutical Journal