HUMAN HEALTH CONCERNS RELATED TO PETS

Three areas where pet ownership can cause problems for human health are:

• disease transmission

• rabies - a special case

• dog attacks on people

Pets can cause many human diseases. Among the better known diseases are rabies, hydatid cysts, bite infections, ringworm, cutaneous and visceral larva migrans, toxoplasmosis and fleabite dermatitis. Owners are either not aware of these risks or they accept the risks of ownership.

While health officials should not overreact to the risks, they have a duty to develop policies that minimise the risks. Part of that duty is to ensure that the community has the facts, despite overstatements and understatements by particular lobby groups.

Leather commented at a recent UAM conference on the ocular toxocariasis debate in Britain.⁹ He said opinions could be easily swayed by proponents on each side of the debate. For example, the pro-dog lobby understated the problem by:

• questioning if the disease existed at all

• arguing that cases may have come from cats or foxes, rather than dogs

• arguing the risk was slight and that health officials were just scaremongering

• complaining that the issue had been raised as just another anti-dog ploy

Meanwhile the anti-dog lobby reacted by overstating the problem and calling for:

• all dogs to be banned, or

• dogs to be banned from all public areas, or

• dog training to be banned from council buildings

In such debates, the emotive arguments of both lobbies can only be countered by informed comment from public health officials.

One disease is so dreadful that it deserves special mention. It is rabies and it is feared by public health officials worldwide. Australia and Antarctica are the only continents that are free of the disease. New Zealand is also rabies-free.

Rabies is an almost invariably fatal viral encephalitis affecting warm-blooded animals. Death comes after a particularly unpleasant sequence of events, starting with infection through a bite from a rabid animal, or through infected saliva entering a wound or mucous membranes.

Rabies is most likely to come to Australia or New Zealand through the entry of an infected animal. Imported animals that could be carrying rabies are placed under quarantine control on arrival. Surveillance is maintained at ports and along the coastlines to detect the illegal importation of animals.

However, due to the long incubation period of this disease, these quarantine measures cannot be 100% effective. Also some animals bypass quarantine by entering illegally.¹⁰

Plans are in place to eliminate the disease if quarantine is breached. In Australia, they are contained in a series of manuals under the common title, AUSVETPLAN (Australian Veterinary Emergency Plan). The main aim will be to contain the rabies outbreak before it spreads to wild populations, and the essential elements of the plans are movement control, compulsory mass vaccination, stray control and community education.¹⁰

The stakes are high. If rabies becomes established in Australia and New Zealand, weíll pay in human suffering, animal suffering, social trauma, environmental degradation and public dollars.

For now, we have to go overseas to get bitten by a rabid dog. But we donít have to go that far to get bitten by an unrabid dog. Dogs that bite are everywhere.

Few things detract more from urban life than the loss of the right to move peacefully along footpaths and through public areas. But in many urban areas, dogs deny this right. For example, in 1996, Brisbane City Council received 1750 formal complaints regarding dog attacks, and 412 dogs were declared dangerous.¹¹ Sadly, school children and elderly people are especially at risk of attack; they often travel on foot through suburban areas. Officials who must visit homes (meter readers, posties, social workers, community nurses) are also at risk.

The publicity given to attacks by strange dogs in public areas sometimes masks a greater threat, the threat of attack at home. In fact, stray (ownerless) dogs are much less likely to bite than dogs with owners known to the victim.¹² A 1991 Adelaide study looked at victims who came to hospital for treatment. Three-quarters of all attacks were made on family members or friends of the dog owner. This statistic fits well with other surveys.¹³ The Victorian Injury Surveillance System reported in 1992 that only one quarter of dog bite injury cases occurred in public areas.¹⁴

When we look at attacks on children, children under 4 are at higher risk of being bitten by a dog or cat than older children, with 2ñ4-year-olds in the highest risk group. Dog and cat bite injuries amounted to 2% of all injuries in one national study. Bites were the most common injuries, the head was the most frequently injured body part, and most of the injuries occurred at home.¹⁵ The majority of children with wounds severe enough to require hospital admission in a Brisbane study were under 6-years-old.¹⁶

With older children, lower limbs are a more likely injury site and boys receive more bites than girls.^{17 12}

Based on the 1991 Adelaide hospital study¹³ and other data from around Australia, it has been estimated that Australian hospitals treat approximately 30,000 dog attack victims each year; in New Zealand more than 5000 are treated.¹⁸ Many more victims go to their GPs or ambulance centres. Still others do not seek any attention. The victims who do not seek medical attention may be in the majority, since most physical injuries are minor and involve a single bite to the extremities.¹⁹

With the increasing trend towards ownership of large and aggressive dogs, the seriousness of individual attacks is growing. Large entire males are more likely to be aggressive than other dogs.¹²

In the 1980s, we heard of no fatal dog attacks in Australia. In the 1990s, there have been at least 5 fatalities so far. American studies have shown that victims of fatal attacks are predominantly young or old. In one study, 70% of victims were under 10-years-old and 21% over 50-years-old.²⁰

Bare statistics canít start to show the degree of public nuisance caused by attacks. Even a minor incident where the dog does not bite can be terrifying for the person involved. No figure can convey the social cost of aggressive dogs: the psychological trauma, the anxiety to families, the loss of work or school time, the restriction of walking due to fear, and the cost to our health care system.

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