Foot and Mouth disease (FMD) is a highly contagious viral disease that affects cloven hoofed animals, those with a split hoof i.e., two toes, such as pigs, cattle, sheep and goats. It is currently exotic to Australia, an enviable status that allows us access to many international export markets.
The disease is characterised by ulcerative type lesions in the mouth and on the nose; teats and feet of infected animals. Whilst it has a low mortality rate in adult animals, deaths are not uncommon in young animals.
The economic impact of FMD reaching Australia is centred around three areas: direct production losses for producers, impacts for the agricultural sector in terms of cost of eradication and loss of trading partners and markets. FMD has been eradicated in many countries, and strict trade controls put in place to prevent re-infection, but outbreaks in FMD-free countries can be extremely expensive.
In 2011, an independent review of Australia’s readiness to deal with an FMD outbreak was conducted. It showed that whilst Australia had strong biosecurity protocols in place, early detection may be delayed due to many Australian veterinarians having not had direct exposure to FMD. As a result, Australia began participating in international real-time FMD training courses from 2012.
The majority of these courses take place in Kathmandu in Nepal, where the disease is endemic, and eradication isn’t possible due to cultural reasons. They have chosen to control FMD via vaccination and, as a result, cannot be considered FMD-free and have limited access to international trading markets. Australia has been sending vets, service providers, government personnel and livestock handlers across a range of industries to these courses each year, since 2012, to ensure Australia is prepared and can detect the disease quickly, should it enter.
The cost of an outbreak to Australia is heavily related to the length of time it goes undetected. A small, quickly detected outbreak may cost approximately $6 billion, whilst a large outbreak could cost upwards of $50 billion.
What are the key points for producers to be aware of if there is an FMD outbreak in Australia?
1. How the virus survives
The virus can survive in the environment, and it survives better in cold, wet environments as opposed to hot, dry environments. It can survive for:
- 14 days on dry faeces
- 39 days in urine
- 6 months in slurry in winter conditions
- 3 days on soil in summer conditions
- Up to 20 weeks on hay or straw
All of these are dependent on pH, temperature, humidity and initial concentration. The virus cannot survive at a pH below 6.5 or above 9.
2. How animals spread the virus
All secretions from an animal can contain the virus: milk, saliva, blood, faeces, breath, oral and nasal fluids, urine, semen, muscle, etc.
Pigs are large airborne shedders of the virus over short time periods, whilst cattle and sheep will shed lower amounts of the virus but for longer periods of time (400 million TCID50/day versus 120,000 TCID50/day respectively).
Virus excretion usually begins up to a day before or the day of clinical sign appearance, but the virus can be detected in milk for up to four days before the appearance of clinical signs.
Virus excretion usually stops 4 – 5 days after the appearance of blister lesions, except in throat fluid. The period of infectiousness for cattle is likely to be between 1 – 5 days.
The virus incubation period is between 1 – 14 days, with 2 - 5 days being the most likely.
3. The main clinical signs in infected animals
a. Salivation, drooling and chomping of the jaw
b. Lameness (pigs will show extreme lameness, smaller ruminants not so much)
c. Reduction in milk production
d. Reduced weight gain
e. Fever
f. Abortions
g. Depression and lethargy
h. Blister type lesions in the mouth, teats and feet
i. Sudden death in young stock
4. How do animals become infected?
a. Direct animal contact – the most likely transmission route
b. Animal products – the virus can be spread through illegal feeding of untreated swill to pigs, or in untreated milk to young animals
c. Mechanical transmission – virus can be present in secretions or excretions on footwear, clothing, vehicles, etc
d. Wind – exhaled airborne virus can be carried by the wind
5. What animals can be carriers of the virus?
a. Pigs are NOT carriers of the virus; they will only spread the virus while infected
b. Cattle can be persistently infected and shed intermittently
c. Shedding occurs independently of the immune status, i.e., it can occur in vaccinated animals
d. Sheep can shed for up to 9 months, goats for up to 4 months, African buffalo for at least 5 years
There is no evidence of a carrier animal causing new infections of the virus, as they only shed a very small amount, with the exception of African buffalo. However, the importance of carrier animals should not be overlooked.
6. Key biosecurity principles to remember
a. Segregation
b. Cleaning – organic matter can deactivate disinfectant, so it needs to be removed prior to disinfection
c. Disinfection – contact time is important, concentration is important and correct PH is important
Some disinfectants effective against FMD are:
- Washing Soda (Na2CO3):4
- Citric Acid: 0.2%
- "FAM30": 1:240
- "Virkon" 1%
Whilst the thought of FMD entering Australia unknowingly is a cause for concern for livestock producers and those that work with producers or livestock, there are many people trained in detection of FMD across the country.
There are a number of procedures that producers can put in place on their farms to reduce the risk and protect livestock. These centre around biosecurity plans, up-to-date NLIS databases and reducing or keeping track of visitors.
It is recommended you have a veterinary approved biosecurity plan in place, that assesses all the risks to your property. Key considerations are livestock movements and visitors. Having an accurate visitors’ log in place, and ensuring anyone who visits your property signs in, and ensuring they are aware of your biosecurity protocols is paramount. Consider: vets, consultants, staff, contractors, family and sales reps, just to name a few. In Nepal, we saw that infections typically travelled through areas from outside sources, such as vets and consultants, visiting multiple farms in a day.
Ensuring your animal movement records are current and up to date will be essential for virus tracing, should an outbreak occur. With thousands of livestock being moved across the country every day, it is essential the team tracing the virus can determine where the outbreak started in order to contain it.
Save the Emergency Animal Disease Hotline number in your phone: 1800 675 888. Available 24 hours day.
The information in this article has come from the EuFMD training course in Nepal, which Milne Feeds Ruminant Sales Manager, Jessica Andony, attended in 2017. Jessica can be contacted on 0435 174 719 or jessica@milne.com.au
