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Home › Topics › Infectious Diseases › Infections A-Z › Zoonoses (infections acquired from animals) ›Epidemiological Data ›  Surveillance of Zoonotic infections
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Surveillance of Zoonotic infections

  1. National surveillance of laboratory-confirmed infections
  2. Sources of data
  3. Notifications
  4. Enhanced surveillance

National surveillance of laboratory-confirmed infections

Surveillance of laboratory-reported zoonotic infections is undertaken by Health Protection Services at the Health Protection Agency Colindale in collaboration with Public Health Wales. National surveillance is maintained on several thousand species, subspecies and subtypes of microbial pathogens, of which zoonotic micro-organisms are a comparatively small proportion.

The following events must occur for data on a given case to be included in a national surveillance database for laboratory confirmed-infections:

  • an infected individual must consult a clinician (GP or hospital doctor)
  • the doctor must arrange for a specimen to be taken (faeces, blood etc.) and referred to a clinical microbiology laboratory
  • the laboratory must isolate and identify a micro-organism, or detect antibodies to an organism 
  • the laboratory must submit a report to the national surveillance centre

The national surveillance schemes for laboratory confirmed infections are not designed to provide direct measures of the numbers of cases of infection in the population caused by those pathogens under surveillance. A number of factors influence the degree of the disparity between the number of recorded laboratory reports for any given pathogen and the number of cases of infection in the population. These include:

  • severity of disease
  • duration of symptoms
  • selectivity of screening protocols employed by diagnostic laboratories
  • sensitivity of available diagnostic techniques

The severity of the disease and the duration of symptoms associated with infection dictate both the proportion of cases that consult clinicians, and the proportion of presenting cases from whom specimens are collected. They vary widely across the range of zoonoses under surveillance in the UK.

Sources of data

There are three main sources of data which together help to build a picture of the burden of zoonotic infection in the human population. These are:

Not all zoonotic diseases are notifiable under Public Health legislation. Recorded human cases represent only the “tip of the iceberg” as many patients do not seek medical attention or, their doctor does not request laboratory investigation and, a positive result is either not notified or the occurrence of the disease is not notifiable. Reports may also be biased towards more clinically severe cases in high risk groups.

Notifications

Notifications relate to clinical disease. All doctors have a statutory duty to notify the proper officer of the local authority of all clinically suspected cases of those diseases specified under the Public Health (Infectious Disease) regulations 1988, and the revisions made in England in 2010. The revised measures are contained within the amended Public Health (Control of Disease) Act 1984 and its accompanying Regulations. These new Regulations for clinical notifications came into force on 6 April 2010, and those relating to laboratory notifications on 1 October 2010.

Notifiable zoonoses include anthrax and rabies. See here for more information

Tuberculosis is also notifiable. Clinical tuberculosis can result from infection with either Mycobacterium tuberculosis (which is not a zoonosis and is spread from person to person) or M. bovis (bovine tuberculosis) infection. It is not possible to use tuberculosis notification data to assess the burden of human infection with bovine tuberculosis in England and Wales.

Food poisoning is notifiable. Food poisoning has been defined as ”any disease of an infectious or toxic nature caused or thought to be caused by the consumption of food or water”. Infections caused by zoonotic agents include the non-typhoidal salmonellas, campylobacters and Cryptosporidium. As with tuberculosis, notifications do not include information on the cause of the disease and it is not possible to determine the number of cases of notified food poisoning which are attributable to specific zoonoses.

Enhanced surveillance

From time to time additional data are collected or specific surveillance studies set up, either nationally or locally, to provide information on certain aspects of a zoonotic infection.


Last reviewed: 17 November 2010