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References to the relationship between environment and the
incidence of dog-borne diseases frequently appear in the medical
press - one interesting report relating to beaches in Australia
(Burry 1978). But the UK Department of Health does
no monitoring and, as far as can be ascertained, has no policy
on dog-related diseases apart from rabies. The World Health
Organisation (WHO) however, regards zoonoses as a major problem
and includes the dog as a vector (World Health Organisation
1979).
As populations of domestic dogs (and cats) become larger
they become greater reservoirs for pathogens. Although intrinsically
the dog is no more a disease vector than many other species,
humans share their living accomodation with the domestic dog,
but not with wildlife. Pets other than dogs can harbour zoonoses,
but it is rare for non-canine pets to be exposed to infections
on a regular basis by being taken for walks time and again
to places contaminated with disease-causing organisms.
The World Health Organisation has produced a circular (World
Health Organisation 1995) concerning mainly research on
toxocariasis in Italy, involving nearly 3000 people, dog owners
included. It had been found in Britain (de Savigny et
al 1979) at one time that 2% of the adults in a healthy
population had toxocariasis antibodies. In Italy however (also
excluding children, who had been found to show a much higher
incidence) the figure was 4%. The Italian work confirms that
Toxocara eggs are more infective than is generally
supposed. A further conclusion was that the risk of infestation
was environmental rather than a hazard associated with dog
ownership. This was confirmed by the observation of peaks
in the frequency of infestation for people involved with soil.
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