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150 years of disease notification – A life-saving procedure

01 March 2017, at 12:00am

The notification of infectious disease cases to a public health authority takes place for both human and animal diseases in Great Britain. Notification is an essential means of disease control, since it enables authority to measure the presence of a given infection in a population, and alerts it to sudden rises in case numbers – such alerts may indicate the occurrence of a local outbreak or the beginning of an epidemic.

Notification was first introduced in England and Wales by order of the Privy Council as a response to imported cattle plague in July 1865. The measure was consolidated in the 1866 Diseases of Cattle Prevention Act, and re-enacted in the Contagious Diseases of Animals Act, 1867 and in subsequent legislation. Notification and slaughter were the core measures of the so-called ‘stamping out policy’ which now became official policy for infection control. The Veterinary Department of the Privy Council, first forerunner of the Department of Environment, Food and Rural Affairs of today, was established on 14 October 1865 (the first Board of Agriculture was created in 1889). Government payment for veterinary services has run continuously since August 1865. The more contentious measure of notification for human infectious diseases was first introduced in 1889.

Notifiable diseases are also known as ‘crowd diseases’ – those with the potential for damaging spread among animal populations. In Britain these include anthrax, foot-and-mouth, tuberculosis, avian influenza, BSE, bluetongue virus, brucellosis, rabies, scrapie and fowl pest, among others. Initial identification is often symptom based, and rests with the person in charge of the animal or carcass known or suspected to be affected. Under current legislation (Requirements under Specified Diseases (Notification) Order, 1996) that person is also responsible for notifying such cases to the Divisional Veterinary Manager, or the local police, but these provisions apply equally to veterinarians inspecting or examining animals, and to persons analysing laboratory samples.

Notification of infectious animal diseases is important as a tool for preventing epidemic outbreaks on at least two counts. First, such epidemics are potentially immensely costly financially to individual farmers, to the state which must operate the control mechanisms, and to the wider economy through movement restrictions, and consequent disruption of non-agricultural activities. Secondly, such epidemics are also immensely costly in terms of emotional stress – to the farmers who care for their animals and are deeply upset by their loss in such circumstances, to the vets who must supervise the culling of infected animals, and even to the general public, who are exposed and involved in such catastrophes via coverage in news media.

The national experience of the foot-and-mouth outbreak of 2001 – which saw 2,000 cases in cattle and sheep, and resulted in the slaughter of 10 million animals, the cancellation of events such as the Cheltenham Festival, the postponement of the General Election, and exposed the general public via news reports to vivid images of animal carcasses piled and burning – was nothing less than a national trauma. And although financial compensation was available under EU regulations to farmers whose animals were slaughtered, the many who suffered financially through movement restrictions were not eligible for compensation. The swift response to a further outbreak in August 2007 reflected the distress of 2001.

Notification is also important on two further counts. In the first place there are animal diseases with the potential also to cause human infections – bovine tuberculosis being a case in point. For the first half of the twentieth century, the campaigns to control tuberculosis in human and bovine populations were linked by widespread human consumption of unpasteurised milk. Pasteurised milk only came to dominate the British market circa 1960, although the sale of unpasteurised milk continues small scale, and still constitutes a hazard to human health, being also linked to various gastro-enteric infections. Secondly, and more worryingly, avian influenza viruses have the potential not only to infect humans, but also to mutate into strains which can be highly lethal both to birds and humans. Influenza viruses are constantly circulating and constantly evolving. A global epidemic of lethal ‘bird flu’ constitutes an ongoing threat to human populations, for which the example of the 1918-19 influenza epidemic – one of the deadliest disease outbreaks in history, estimated to have killed 50 million people worldwide – provides a terrible blueprint.

Animal infectious diseases represent a constant potential problem for both animal and human health. Aside from the biggest threats to British animal populations – undoubtedly bovine tuberculosis, avian influenza, fowl pest and foot-and-mouth disease – the importation of brucellosis and new infections such as Schmallenberg virus in sheep are also a cause for concern. Other infections hover: the NFU, for example, issued a serious bluetongue alert in July 2016. The range of infections on the list of notifiable diseases, from African horse sickness through rabies to salmonellosis and viral haemorrhagic disease, is testimony to the dangers inherent in international communications, whether by air or sea, via birds, smuggled animals, livestock or even imported meats.

In the case of animal infections, as with human infections, the price of safety is eternal vigilance. Britain’s farming community, whose flocks and herds, being animal crowds, are especially vulnerable to viral, airborne, and insect-borne infections, constitutes the first line of defence against outbreaks. Knowledge of the symptoms of likely infections, careful attention to any manifestation of illness, prompt notification, and veterinary attention are essential.

Veterinarians themselves have an important part to play in educating the farming community, passing on alerts for outbreaks and likely importations both to local farmers and local police, and in responding promptly to ominous-sounding call-outs. Communication with the NFU and the BBC’s Farming Today programme, which also act to channel information to the farming community, offers further routes for dissemination of developments on infectious threats. The lynchpin which holds these preventive measures together is, however, notification. Without a nationally accepted and effective system of infection notification, Britain’s livestock, avian, bovine, equine and ovine, will always be vulnerable to the potentially devastating crowd infections which are particular to their species.

Honorary Professor of the History of Public Health at London School of Hygiene and Tropical Medicine

Anne was on the academic staff of the Academic Unit of the Wellcome Trust Centre for the History of Medicine at UCL from 1990 to 2010. She is the author of several books on infectious diseases and public health.

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