Foot and Mouth Disease p. 83 - Flashcards
Foot and Mouth Disease can not be reliably clinically differentiated from which diseaes?
o Swine vesicular disease (SVD)
o Vesicular exanthema of swine (VES)
o Vesicular stomatitis (VS)
o Laboratory diagnosis of any suspected FMD case is therefore urgent
Transmission of FMD
Not zoonotic!
• Direct or indirect contact (aerosol)
• Animate vectors (humans, visitors and including vets, etc.)
• Inanimate vectors (vehicles, implements)
• Wind, especially temperate zones (up to 60 km overland and 300 km by sea)
Resistance to physical and chemical action
• Temperature: resistant to low temperature and inactivated by high temperature
• pH: inactivated by pH below 6.0 or above 10.0
• Chemicals:
o inactivated by sodium hydroxide (2%), sodium carbonate (4%), citric acid (0.2%), aceti
cacid (2%), sodium hypochlorite (3%), potassium peroxymonosulfate/sodium chloride
(1%), and chlorine dioxide
o Resistant to iodophores, quaternary ammonium compounds, and phenol, especially in
the presence of organic matter.
• Disinfectants:
o inactivated by caustic soda, formalin, iodophores and acid.
o resistant to phenol, quaternary ammonium compounds, alcohol and lipid solvents
• Survival: persists on hay/straw for over 15 weeks, and in dried hides for much longer. Survives
well in lymph nodes and bone marrow but destroyed in muscle
From where do we take samples in case of FMD?
The preferred tissue for diagnosis is epithelium from unruptured or freshly ruptured vesicles.
• Where this is not possible, saliva and blood and/or oesophageal-pharyngeal fluid samples taken
by probang cup in ruminants or throat swabs from swine provide an alternative source of virus.
Myocardial tissue or blood can be submitted from fatal cases, but vesicles are again preferable if
present. It is vital that samples from suspected cases be transported under secure special
conditions and according to international regulations. They should only be dispatched to
authorized laboratoriesq
Sampling for FMD!!
• 1g of tissue from an un-ruptured or recently ruptured vesicle. Epithelium samples should be
placed in a transport medium which maintains a pH of 7.2-7.4. Samples should be kept at 4oC.
• Oesophageal-pharyngeal fluid collected by means of a probang cup (a special device for
collecting cells from the walls of the upper part of the oesophageus).
Measures in case of suspicion of an outbreak
• Official investigation: sampling and laboratory testing
• Official surveillance: census of all animals
• Isolation
• All products of animal origin are recorded
• Epidemiological inquiry
• Movements onto and off the holding of animals or products of animal origin are banned
• Movements of persons are subject to strict rules
• Temporary control zone may be established for up to 72 hours (until excluding/confirming disease)
• Preventive eradication programme may be implemented, including the slaughter of animals
suspected of being infected
Measures in case of confirmation of an outbreak of FMD
• All animals of susceptible species on the holding are killed on the spot – Incinerated…
• Any other animals present may be killed
• Samples and epidemiological inquiry
• Carcasses are processed without delay
• All products of animal origin present on the holding since the presumed date of
introduction of the disease are treated to destroy the virus
• Buildings and vehicles used are cleaned and disinfected under official surveillance
• Restocking of the holding may begin 21 days after cleaning at the earliest
Measures in the Protection zone of FMD
• A minimum radius of 3 km
• National and local disease control centres
• Tracing of all susceptible animals and animal products
• Registration of all holdings and establishment: regular veterinary inspections
• Animals of susceptible species must remain on the holding except where they are emergency
slaughtered in a slaughterhouse outside the protection zone – may authorise separate slaughter
at designated slaughterhouse
• Fairs, markets and shows for ungulates and artificial insemination are prohibited
• Private practitioners advised to help in these cases (paid by the state) – obligatory!
• Ban of transport of susceptible animals
• Prohibition of the placing on the market of meat and meat products derived from animals of
susceptible species
• Milk and milk products, semen, ova and embryos, hides and skins, wool, hair, bristles animal
feed, fodder, hay and straw: special treatment and/or strict veterinary control or ban
• The measures are maintained and complied with until:
o At least 15 days have elapsed since the killing and disposal of all the animals on the
holdings affected by FMD;
o A survey in all holdings in the protection zone has been concluded with negative results.
Measures in the surveillance zone of FMD
• A minimum radius of 10 km
• Tracing of all susceptible animals and animal products
• Census of the holdings and the animals on them, (obligatory to inform vet authority – but in case of
outbreak still need to go in and actually double check)
• A ban on transporting susceptible animals
• Restrictions on the placing on the market of meat and products of animal origin
• After the removal of the measures applied in the protection zone, the measures applied in the
surveillance zone continue to apply for at least two weeks
Suppressive Vaccination of FMD
not used in other diseases
o Part of an immediate stamping-out strategy
o Applied to ensure minimum spread of the virus during disposal of infected animals – if
cannot kill all of them quickly, so to delay the time of infection we can vaccinate to
suppress the spread
o Carried out only within the protection zone and on clearly identified holdings
Protective vaccination of FMD
same as in other species
o Regionalisation of the vaccination zone
o Second surveillance zone: at least 10 km wide
Recovery of FMD free and infection free status if no vaccination has been used?
o The control and eradication measures laid down for the protection and surveillance zones
have been effective and may be lifted and
o At least three months have elapsed after the last recorded outbreak
Recovery of FMD free and infection free status if vaccination has been used:
o The control and eradication measures laid down for the protection and surveillance zones
have been effective and may be lifted and
o At least three months have elapsed since the slaughter of the last vaccinated animal and
serological surveillance has been carried out; or
o At least six months have elapsed since the last outbreak of foot-and-mouth
disease or the completion of emergency vaccination
