Notifiable disease Flashcards
Define ‘Notifiable Disease’ in the context of the UK.
A notifiable disease is an animal disease that must be reported to the Animal and Plant Health Agency (APHA) by law, even if it is only suspected. Failure to report can lead to legal consequences.
Define ‘Reportable Disease’ in the UK.
A reportable disease is usually recorded by a laboratory upon diagnosis and is used for surveillance purposes rather than initiating immediate action.
What are ‘Transboundary Diseases’?
Internationally important diseases that can cross borders and impact global animal health. In the UK, many of these diseases are classified as notifiable.
Why are some animal diseases designated as notifiable in the UK and internationally?
To ensure quick action to prevent widespread outbreaks, protect public health, and safeguard the economy and food supply. This requires consistent and transparent reporting to international organizations like the World Organisation for Animal Health (WOAH).
What are the main principles for preventing imported and exotic infections in animals?
Principles include strict quarantine measures, controlling animal movements, and applying rigorous biosecurity protocols to minimize the risk of introducing diseases from other regions.
Describe the quarantine procedures for preventing exotic infections.
Quarantine involves isolating animals for a specified period to ensure they do not show signs of infectious diseases before allowing them into a general population. It includes monitoring and, if necessary, testing for specific pathogens.
What should be done if a notifiable disease is suspected?
Report immediately to APHA. A duty vet will discuss the case and may visit the site. If suspicion remains, samples are taken, and the location becomes a ‘Suspect Premises’ with restricted movements and biosecurity measures.
What steps are taken if Foot and Mouth Disease (FMD) is suspected?
- Notify APHA immediately
- Restrict animal movements
- Implement biosecurity measures
- If confirmed:
- Establish 3 km Protection Zone
- Establish 10 km Surveillance Zone - Humane culling of affected animals if required
What happens when FMD is confirmed?
CVO (chief veterinary officer) informs WOAH (World Organisation for Animal Health)
The UK loses FMD-free status
Protection (3 km) and Surveillance (10 km) Zones enforced
Affected animals are culled
Epidemiological investigations begin to trace source and spread
Describe some control strategies for Foot and Mouth Disease (FMD).
Control strategies include strict biosecurity, immediate culling of affected animals, and establishing zones to contain the outbreak. Export restrictions and continuous monitoring are also enforced.
What are some examples of notifiable diseases in the uk
FMD
Bovine TB
Rabies
Avian ‘flu
Anthrax
Describe FMD (notifiable disease)
Aphthavirus - picornavirus
Survives well in environment (~ 1 month)
Readily transmitted on equipment, clothes, vehicles, wildlife (as fomites) and wind.
Infects ruminants and pigs (plus some other spp) causing subclinical-to-severe disease
+/- zoonotic?
Last major outbreak in the UK in 2001, further (lab escape) breakdown in 2007
Vesicles/ulcers in mouth, on tongue and feet, lameness, fever, markedly reduced production
What is Bovine Tuberculosis (bTB)
bTB is a chronic infectious disease in cattle caused by Mycobacterium bovis, leading to reduced production and is zoonotic via milk, but pasteurization prevents human transmission.
How is Bovine TB transmitted among cattle?
Long-distance transmission occurs primarily through cattle movement, while most local transmission happens between cattle in large, housed herds.
What is the role of badgers in the transmission of bTB?
Badgers can maintain bTB and transmit it to cattle and vice versa. However, cross-species transmission is less common compared to transmission within the same species.
Why is controlling bTB in badgers controversial?
Control is controversial because badger testing is difficult. Approaches include culling or vaccination, with debates on effectiveness and ethical concerns, especially due to the perturbation effect.
What are the main diagnostic tests used for bTB in cattle?
Tests include single and comparative skin tests, gamma-interferon tests, post-mortem examination, and antibody-based tests like the Enferplex and phage tests.
What is the comparative sensitivity and specificity of the skin test for bTB in cattle?
The single intradermal comparative cervical test (SICCT) has a sensitivity of around 70-80% for individuals and a specificity of about 99.5%.
What is the purpose of culling and vaccination in bTB control?
Culling is used to remove infected cattle, while vaccination (e.g., with BCG) is used to prevent future infections. However, no vaccine is 100% effective, and DIVA tests are needed to distinguish vaccinated from infected animals.
What are the benefits and drawbacks of culling badgers as a bTB control strategy?
Culling may reduce bTB in cattle by 15-20% in endemic areas but can lead to the perturbation effect, causing increased transmission among badgers. Vaccination is a potential alternative but requires further research.
Describe how bTB is detected and confirmed in cattle at abattoirs.
Skin test-positive cattle are sent to designated abattoirs. If bTB lesions are found, affected tissues are condemned. Routine abattoir testing is crucial for bTB surveillance in countries with eradication programs.
What is the ‘perturbation effect’ in relation to badger culling?
The perturbation effect occurs when culling disrupts badger social structures, leading to increased movement and potentially higher transmission rates of bTB.
How does the prevalence of bTB in a population affect the predictive values of diagnostic tests?
Lower prevalence decreases the Positive Predictive Value (PPV) of a test, meaning a positive result is less likely to indicate true infection, even with high test specificity.
What is the significance of strain typing in bTB control?
Strain typing, such as whole genome sequencing, is used to trace the epidemiology of bTB and understand the sources and routes of transmission, aiding in targeted control measures.
