What is a Notifiable Disease in Animal Health?

In some of our recent articles, we’ve discussed various notifiable diseases like bluetongue, foot-and-mouth disease, avian influenza, and sheep scab. But what exactly is a notifiable disease and what do you have to do if you suspect one?

What is a notifiable disease?

Simply put, a notifiable disease is disease which, if suspected or confirmed, by law must be reported to an appropriate authority. In the UK, this is the Animal and Plant Health Agency (APHA). Similarly, a notifiable causative agent is an organism which, if detected, must be reported. Often, the diseases which fall under this classification have the potential to cause severe problems, are zoonotic, or are very easily transmissible.

Different countries have different notifiable diseases, but there are some diseases that are globally notifiable. For human diseases like cholera, plague and yellow fever, the relevant authority is the World Health Organisation (WHO). For animal diseases, the World Organisation for Animal Health (OIE) deals with any globally reported diseases. Some diseases can be globally notifiable, but not locally. For example, equine influenza is not a notifiable disease in the UK, but is globally, so vets and owners must report it to the OIE.

If a lab finds evidence of any notifiable disease, they must inform the relevant authorities.
If a lab finds evidence of any notifiable disease, they must inform the relevant authorities.

Why are some diseases notifiable?

Not all infectious diseases are classified as notifiable. Generally, the main factors in classifying a disease are the severity of the disease, how easily it spreads, its virulence, its potential for significant impact, and what measures are available to fight it.

Foot-and-mouth disease is a good example of this. It is a severe disease, as it causes significant illness in infected animals. Animals suffering from the disease are almost always culled. It spreads easily and quickly through mechanical means and is sometimes airborne. The impact of the disease is enormous, both on the agricultural industry and on the wider community. An outbreak of foot-and-mouth can prevent any internal animal trade and completely stop international trade. In terms of available control measures, although there is a vaccine for the disease, usually prevention is the primary means of control. These factors combine to produce a disease that is a prime candidate for notifiable status.

Once a disease is classified as notifiable, it becomes easier to track and reduce spread. Infections are more quickly and easily contained and epidemics are much less likely to occur. The notifiable status of diseases like smallpox and rinderpest aided in their eradication.

What happens when someone suspects a notifiable disease?

There are around 41 animal notifiable diseases in the UK. In Scotland, warble fly, sometimes seen in cattle, is also notifiable. If a vet or farmer suspects any of these diseases, they must report it to the APHA. Once this has happened, APHA vets will investigate to determine if the disease is present. Simultaneously, APHA will place the premises under movement restrictions. Depending on the disease, sometimes APHA will establish a temporary control zone.

One of the criteria to classify a notifiable disease is its potential impact.
One of the criteria to classify a notifiable disease is its potential impact.

The restrictions will continue for the duration of the investigation. If the disease is not present, the restrictions will then be lifted. If the disease is present, next steps will depend on which disease it is. In foot-and mouth disease for example, control usually takes the form of culling any affected animals, and preventative culling of at-risk animals. Investigations will attempt to establish the source of the infection and consider if widespread restrictions are necessary. Once the disease is no longer a threat, health organisations can remove the restrictions.

What resources are there on notifiable diseases?

The APHA and Defra have compiled a list of guidance on each of the notifiable diseases. These documents give information on how to spot the disease and what to do if you do spot it. If you’re looking for information on human notifiable diseases, Public Health England produce a weekly report that gathers information from across the country.

For information on global notifiable animal disease, the OIE have many useful resources including a list of all listed diseases and links to further information on specific infections. Similarly, the WHO have many resources on different diseases and their status.