Foot-and-mouth disease (FMD) is a highly infectious and notifiable disease (it is required by law to be reported to the government - specifically Animal Health and Plant Agency, APHA), for economic reasons, and is zoonotic (can go from animals to humans), however it is spread from the handling of infected animals (not from eating meat from an infected animal) and results in a temporary and mild infection [1][2]. It affects cloven-hoofed animals, such as cattle, sheep, deer, goats and pigs. It can also affect buffalo, giraffes and elephants. Horses, cats and dogs cannot contract FMD, although can aid the spread of disease between areas.
Causes
FMD is caused by an aphthovirus (a viral genus of the family Picornaviridae), of which there are 7 serotypes (distinct variations within a species of bacteria, viruses or among immune cells of different individuals), within which there are a multitude of strains.
It can be spread by contact with infected animals or coming into contact with the substances from infected animals (i.e. exhaled air, saliva, milk, faeces, urine). It can also be spread indirectly, through objects that an infected animal has come into contact with (i.e. vehicles, equipment, clothes). The virus can be transmitted by an infected animal up to ten days before the appearance of blisters, with the disease having an incubation period (the time between exposure to a disease, and the onset of symptoms) of between 2 to 14 days, dependent on the strain of the virus and the susceptibility of the host.
"The virus is inactivated within three days in carcasses that have undergone normal post-slaughter acidification, it can survive for months in chilled lymph nodes, bone marrow, viscera and blood clots. Virus has been detected in milk and semen for up to 56 days after infection. Some recovered animals remain long-term carriers." [3]
Symptoms & Diagnosis
(Shared symptoms)
Sores and blisters on the hooves (In cattle, sheep and pigs)
Sores and blisters in the tongue or on the mouth (Mainly in cattle, but may also occur in sheep)
Lameness, which may develop and spread across the flock or herd (In cattle, sheep and pigs)
Tendency to lie down (In sheep and pigs)
Unwillingness to move when made to stand (In sheep and pigs)
"Mortality is normally less than 5%, but may be high in young animals." [4]
(Individual symptoms)
Clinical signs shown by cattle are shivering, fever, lameness, blisters on teats and udders, slobbering, smacking lips and reduced milk production from cows.
Clinical signs shown by sheep are tiredness in young lambs, ewes refusing to let lambs suckle or an increased number of stillbirths, abortions and lambs dying soon after birth.
Clinical signs shown by pigs are reluctance to feed, loudly squealing from pain and blisters on the snout.
"In cattle and pigs, the clinical signs of FMD are indistinguishable from those of vesicular stomatitis (see Vesicular Stomatitis), and in pigs from those of swine vesicular disease (see Swine Vesicular Disease) and vesicular exanthema (see Vesicular Exanthema of Swine). [...] Samples must be kept as close as possible to pH 7.4 to prevent destruction of the FMD virus and antigen. They should be securely packed in double leak-proof containers that comply with national and, when appropriate, international regulations for the shipment of pathologic and hazardous material.
Samples are prepared as a 10% suspension, inoculated onto susceptible tissue culture, and directly typed by ELISA. Isolated FMD virus is characterized by antigenic comparison with existing FMD vaccine strains, and the nucleotide sequence of a segment of the 1D gene is determined for comparison with other strains of the same serotype to identify a possible origin of the outbreak." [5]
Rapid diagnostic kits are becoming more readily available, to allow diagnosis to be done on the farm, however these need to be validated.
Treatment
The protection zone is all those located within 3 kilometres from the premises (of where the infection was found). There are no movements allowed within this zone, with all animals being located, inspected, and any disease identified.
The surveillance zone is all those located within 10 kilometres from the premises. All animals within this zone are located, with very few movements allowed.
Other controls implemented may include the mandatory registration of all premises in the surrounding area.
Many countries free of FMD have a policy of slaughter of all affected and in-contact susceptible animals and strict restrictions on movement of animals and vehicles around infected premises. After slaughter, the carcasses are either burned or buried on or close to the premises, and the buildings are thoroughly washed and disinfected with mild acid or alkali and by fumigation. Tracing is done to identify the source of the outbreak and premises to which FMD virus could have already been transmitted by infected animals or animal products, by contaminated vehicles or people, or aerosol.
References - provided general understanding of the disease; including symptoms, causes and treatments
Foot and mouth disease overview
https://www.daff.qld.gov.au/animal-industries/animal-health-and-diseases/notifiable/foot-and-mouth-disease/overview
- Referenced spread and affect of disease on humans [1]
- Quote, How long the virus survives after the death of the infected animal [3]
- Quote, mortality rate of older animals [4]
Aphthovirus (cause of foot-and-mouth disease)
http://www.biodiversityexplorer.org/viruses/aphthovirus.htmn
- Referenced spread and affect of disease on humans [2]
http://www.merckmanuals.com/vet/generalized_conditions/foot-and-mouth_disease/overview_of_foot-and-mouth_disease.html#v3272923
- Quote, diagnosing FMD [5]
- Quote, control of FMD [6]
Foot and mouth disease: How to spot and report it
https://www.gov.uk/foot-and-mouth-disease
Charlotte O'Connor
Causes
FMD is caused by an aphthovirus (a viral genus of the family Picornaviridae), of which there are 7 serotypes (distinct variations within a species of bacteria, viruses or among immune cells of different individuals), within which there are a multitude of strains.
It can be spread by contact with infected animals or coming into contact with the substances from infected animals (i.e. exhaled air, saliva, milk, faeces, urine). It can also be spread indirectly, through objects that an infected animal has come into contact with (i.e. vehicles, equipment, clothes). The virus can be transmitted by an infected animal up to ten days before the appearance of blisters, with the disease having an incubation period (the time between exposure to a disease, and the onset of symptoms) of between 2 to 14 days, dependent on the strain of the virus and the susceptibility of the host.
"The virus is inactivated within three days in carcasses that have undergone normal post-slaughter acidification, it can survive for months in chilled lymph nodes, bone marrow, viscera and blood clots. Virus has been detected in milk and semen for up to 56 days after infection. Some recovered animals remain long-term carriers." [3]
Symptoms & Diagnosis
(Shared symptoms)
Sores and blisters on the hooves (In cattle, sheep and pigs)
Sores and blisters in the tongue or on the mouth (Mainly in cattle, but may also occur in sheep)
Lameness, which may develop and spread across the flock or herd (In cattle, sheep and pigs)
Tendency to lie down (In sheep and pigs)
Unwillingness to move when made to stand (In sheep and pigs)
"Mortality is normally less than 5%, but may be high in young animals." [4]
(Individual symptoms)
Clinical signs shown by cattle are shivering, fever, lameness, blisters on teats and udders, slobbering, smacking lips and reduced milk production from cows.
Clinical signs shown by sheep are tiredness in young lambs, ewes refusing to let lambs suckle or an increased number of stillbirths, abortions and lambs dying soon after birth.
Clinical signs shown by pigs are reluctance to feed, loudly squealing from pain and blisters on the snout.
"In cattle and pigs, the clinical signs of FMD are indistinguishable from those of vesicular stomatitis (see Vesicular Stomatitis), and in pigs from those of swine vesicular disease (see Swine Vesicular Disease) and vesicular exanthema (see Vesicular Exanthema of Swine). [...] Samples must be kept as close as possible to pH 7.4 to prevent destruction of the FMD virus and antigen. They should be securely packed in double leak-proof containers that comply with national and, when appropriate, international regulations for the shipment of pathologic and hazardous material.
Samples are prepared as a 10% suspension, inoculated onto susceptible tissue culture, and directly typed by ELISA. Isolated FMD virus is characterized by antigenic comparison with existing FMD vaccine strains, and the nucleotide sequence of a segment of the 1D gene is determined for comparison with other strains of the same serotype to identify a possible origin of the outbreak." [5]
Rapid diagnostic kits are becoming more readily available, to allow diagnosis to be done on the farm, however these need to be validated.
Treatment
The protection zone is all those located within 3 kilometres from the premises (of where the infection was found). There are no movements allowed within this zone, with all animals being located, inspected, and any disease identified.
The surveillance zone is all those located within 10 kilometres from the premises. All animals within this zone are located, with very few movements allowed.
Other controls implemented may include the mandatory registration of all premises in the surrounding area.
Many countries free of FMD have a policy of slaughter of all affected and in-contact susceptible animals and strict restrictions on movement of animals and vehicles around infected premises. After slaughter, the carcasses are either burned or buried on or close to the premises, and the buildings are thoroughly washed and disinfected with mild acid or alkali and by fumigation. Tracing is done to identify the source of the outbreak and premises to which FMD virus could have already been transmitted by infected animals or animal products, by contaminated vehicles or people, or aerosol.
References - provided general understanding of the disease; including symptoms, causes and treatments
Foot and mouth disease overview
https://www.daff.qld.gov.au/animal-industries/animal-health-and-diseases/notifiable/foot-and-mouth-disease/overview
- Referenced spread and affect of disease on humans [1]
- Quote, How long the virus survives after the death of the infected animal [3]
- Quote, mortality rate of older animals [4]
Aphthovirus (cause of foot-and-mouth disease)
http://www.biodiversityexplorer.org/viruses/aphthovirus.htmn
- Referenced spread and affect of disease on humans [2]
http://www.merckmanuals.com/vet/generalized_conditions/foot-and-mouth_disease/overview_of_foot-and-mouth_disease.html#v3272923
- Quote, diagnosing FMD [5]
- Quote, control of FMD [6]
Foot and mouth disease: How to spot and report it
https://www.gov.uk/foot-and-mouth-disease
Charlotte O'Connor