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Flashcards in Notifiable diseases Deck (54)
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What are the reasons for a disease being notifiable?

- Internation trade
- Public health (but not always zoonosis)
- Animal welfare
- Wider society
- Due regard for cost to the community and availability of appropriate solutions


What are the criteria for the inclusion of a disease, infection or infestation in the OIE notifiable disease list?

1: Proven international spread of agent
2: At least one country has demonstrated freedom or impending freedom from the disease in a population of susceptible animals, based on provisions of Terrestrial Code
3a: natural transmission to humans proven, associated with severe consequences
3b: disease causes significant morbidity/mortality in domestic animals at level of zone/country
3c: disease shown to/indicated to cause significant morbidity/mortality in wild animal populations
4: reliable means of detection and diagnosis and precise case definition available


What must be included when informing the OIE of an important epidemiological event by sending an Immediate Notification?

- Reason for notification
- Name of disease
- Affected species
- Geographical area affected
- Control measures applied
- Any laboratory tests carried out or in progress


What is the role of the OIE regarding disease?

- Support Member Countries' efforts to prevent transboundary spread of important animal diseases incl. zoonoses
- Transparent and consistent reporting
- Harmonisation of disease detection, prevention and control


Describe the list of Human Notifiable Infectious Disease UK

- Medical practitioners have statutory duty to notify the "proper office" at local council or local health protection team of suspected cases of certain diseases
- Aims to detect outbreaks of disease and epidemics as rapidly as possible
- Some are zoonoses that are not notifiable when affecting animals
- Includes syndromes as well as disease agents


Outline the WHO system of notifiable diseases

- International Health Regulations 2005
- Member states notify WHO of events of urgent and international importance, instead of disease specific notification
- Consult with WHO in circumstances not at time requiring notification or where related guidance is needed
- Aim to catch emerging/new diseases/syndromes
- Algorithm used to decide whether to report


What actions are required following identification of a potential zoonotic disease?

- Report to appopriate authority e.g. APHA, FHI (fish health inspector), OIE, regional bee inspector or NBU (national bee unit)
- e.g. FMD, duty VO discuss case over phone, must stay on farm, movement restrictions effective immediately samples sent to lab, farm declared Suspect Premises


Describe Rinderpest

- AKA cattle plague
- Eradicated globally in 2011
- Morbillivirus, closely related to: measles, canine distemper, pest de petit ruminants
- Affects ruminant and swine


Describe peste de petit ruminants

- Goat plague (affects sheep and goats)
- Morbillivirus
- fever and depression, severe discharge from eyes and nose, coughing, diarrhoea, death
- Does not usually kill goats and sheep, does cause severe disease and loss of production
- Spreading to Greece and Turkey


Describe Classical Swine Fever

- Aka hog cholera, pig plague
- Pestivirus
- Transmitted in bodily fluids and tissues of sick or dead animals
- Vertical transmission outcome depends on strain and stage of gestation
- Congenital infection can be persistently viraemic, shed for 6-12 months before dying
- Fever, huddling, blotchy skin lesions, convulsions and death


Describe African Swine Fever

- Asfaviridae
- Sub-saharan Africa, Sardina, Caucasus, Northwest Russia
- Severe disease, high mortality
- (Sometimes bloody) V/D, reddening/darkening of skin (esp. ears, snout), gummed up eyes, laboured breathing and coughing, abortion, still births, weak litters, weakness, unwillingness to stand
- Spread by direct contact, faeces, body fluids, fomites, Ornithodoros ticks


Describe Capropoxvirus

- Poxviridae
- Lumpy skin disease
- Spread to Greece and other parts of Eastern Europe, now under control and spread prevented


Describe Foot and Mouth Disease

- Apthavirus (picornavirus)
- Quick mutation
- Survives 1 month in environment
- Transmitted on fomites and wind
- Can cause sub-clinical to severe disease
- Some concern over zoonosis (not shown in practice)
- Vesicles/ulcers in mouth, on tongue, feet, lameness, fever, markedly reduced production
- Pigs produce large amounts of virus as aerosol


Outline the steps following suspicion of an FMD case

- Report to APHA by telephone, discuss with duty VO, visit to farm
- Sample taken, sent to Pirbright, farm declared "Suspect Premises"
- Formal confirmation by Chief Veterinary Officer, informs OIE and EC, reports regularly to both
- England loses FMD free status, exports of cattle and cattle products stop (min. from within control zone)
- Protection zone, surveillance zone and restricted zone put in place


Where is the protection zone in an FMD outbreak?

Minimum of 3km radius from the IP


Where is the surveillance zone in an FMD outbreak?

Minimum of 10km radius from IP


Where is the restricted zone in an FMD outbreak?

National movement ban across GB


Describe the requirements placed on suspected premises of FMD

- Warning/keep out signs
- Records of animals, bedding etc on site
- Isolation of animals
- Prevention of movement of animals and any movements on and off farm that may spread infection
- Disinfectants at entrances and exits
- Rodent control


Describe the requirements placed on infected premises of FMD

- Restrictions imposed on premises remain in force
- Susceptible animals humanely culled
- Carcasses disposed of and preliminary disinfection carried out on farm
- Epidemiological investigation continues to establish where the disease came from and where it may have spread


Describe carcass disposal in FMD

- Normally commercial incineration, rendering or licensed commercial landfill
- Ensure on-farm pyres or mass burial not used in future (but cannot be ruled out if demand exceeds capacity of preferred disposal options


Describe pre-emptive culling in FMD

- Animal Health Act allows culling of animals NOT exposed to FMD infection where at risk
- Only where disease control (slaughter) protocol published, vaccination considered
- Vaccination preferred, aim to avoid pre-emptive culling


Outline the requirements placed on contact premises in an FMD outbreak

- If high risk: premises considered dangerous contact, animals culled
- If low risk: premises and animals under restriction, health status monitored for 3-4 weeks from last known contact with IP, sampled on epidemiological basis


Explain what is meant by contact premises in FMD

- Premises where disease may have come from or spread to
- Can arise through: movement of animals, people, farm equipment, vehicles, slurry/manure, geographical location
- When contact premises identified, assessment made about level of risk (high/low)


What are the impacts of an FMD outbreak?

- Significant economic costs to farmer and government
- Welfare culling if movement restrictions prevent access to food
- Employment of temporary staff


Describe bovine tuberculosis epidemiology

- Combination of diseases, M. tuberculosis, bovis and microti
- Zoonotic, controlled by pasteurisation
- Mainly older animals
- Most long and short distance transmission is between cattle
- In some areas, badgers are main source of bTB outbreaks


List the potential tests for bTB

- Single and comparative skin tests
- Gamma interferon tests
- Post-mortem examination and culture of all positive tests for gamma-interferon and comparative skin tests
- Others


Describe the skin tests for bTB

- Single Intradermal Comparative Cervical Tuberculin (SICCT)
- Clip 2 sites at border of anterior and middle third of neck, 12.5cm apart, 10cm below crest, measure thickness of skin fold with calipers
- Avian tuberculin inoculated into top site, bovine tuberculin into lower
- 72 hours later measure thickness
- Delayed hypersensitivity reaction causes thickening of skin if there is a reaction


Describe the bTB blood test

- Into laboratory within 5 hours of sampling
- Measure interferon gamma released by WBCs
- WBC production increased on stimulation, if exposed before (i.e. positive) leads to increased release of IFN-y


Describe bTB testing monitoring in abattoirs

- Testing important for surveillance
- Skin-test positive cattle sent to designated abattoirs
- If only 1 lesion found in lymph node then nodes and viscera condemned but rest is fit for human consumption
- Widespread and larger lesions likely to be found in non-reactor cattle
- Skin test positive animals detected early so have few or no lesions usually


What is spoligotyping and what is it used for?

- Specific Oligonucleotide Typing
- Looks for presence/absence of variable length "spacers" between repeated sequences
- Consider as bar code
- Used in bTB epidemiology investigations