Hoof and Mouth Disease (HMD)
Hoof-and-mouth disease (HMD), also known as foot-and-mouth disease (FMD), is a highly contagious viral infection affecting cloven-hoofed animals, including cows, pigs, sheep, and goats. It is important to note that HMD does not pose a threat to humans, though it can be transmitted from humans to animals through contaminated materials. The disease is characterized by symptoms such as fever, painful blisters in the mouth and on the feet, and can result in significant economic losses for livestock farmers due to decreased productivity and potential secondary health issues in animals.
The virus that causes HMD, belonging to the genus Aphthovirus, can spread rapidly among livestock, leading to outbreaks that may halt international trade in affected regions. Although there is no specific treatment for HMD, vaccinations exist, but they are tailored to specific types and subtypes of the virus rather than being universal. Countries with outbreaks often implement strict containment measures, including quarantining infected animals and potential euthanasia of affected livestock to prevent further spread. HMD remains a serious animal health concern globally, with areas in Africa, Asia, Europe, and South America being particularly vulnerable, while regions like North America and Australia have successfully eradicated the disease.
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Hoof and Mouth Disease (HMD)
Hoof-and-mouth disease (HMD), also known as foot-and-mouth disease (FMD), is a highly contagious viral disease of cloven-hoofed animals. The disease is not related to the common childhood virus of a similar name: hand, foot, and mouth disease. HMD does not affect humans. It can spread quickly among livestock and cause great economic loss to farmers.
Background
Hoof-and-mouth disease (HMD) only affects animals with cloven hooves such as cows, pigs, sheep, deer, water buffalo, yaks, and goats. It does not affect dogs, cats, or horses. While it can be passed from humans to animals through contaminated materials, humans cannot catch the disease.
HMD causes fever in animals. It causes blisters known as vesicles that show up inside and outside of the mouth, on the tongue and lips, on and around the hooves, and around the mammary glands. The blisters grow quickly and pop open. They leave red areas called erosions. The blisters themselves and red areas left by the blisters can be very hard to see on infected animals. The affected areas are very painful to the animals and cause secondary symptoms. These include weight loss; unwillingness to eat; depression and lethargy; drooling and excessive salivation; changes in saliva and other bodily secretions; lameness and refusing to stand up or move; spontaneous abortion in pregnant animals; low milk production; and heart disease.
Animals with HMD generally do not die from the disease; however, newborn animals that contract HMD are more likely to die from the virus. Death rates are higher among calves and piglets than other animals. HMD makes animals very weak and usually unable to produce meat or milk. It also might leave the animals unable to produce offspring. Animals with HMD are useless to livestock farmers and ranchers who depend economically on the animals for meat and milk products. HMD is highly contagious and can quickly spread from animal to animal. One single case of HMD can cease international trade of livestock for extended periods and can financially hurt everyone involved in the livestock trade industry.
A virus from the genus Aphthovirus in the family Picornaviridae causes HMD. Of the seven types of HMD, sixty subtypes exist. However, some animals are resistant to certain strains. For example, a certain strain that only affects pigs does not infect cows. In addition, some animals can be immune to one type or subtype, but this immunity will not protect them against the other strains. Once an animal is exposed to the virus, it usually takes about two to fourteen days for the illness to present.
The virus can live in the breath droplets, excretions, saliva, and urine of animals. In some cases, the virus can live several months on contaminated matter in the environment if the right conditions exist. The virus is killed by time, temperature fluctuations, and pH changes. Hooved animals exposed to HMD are at a great risk of developing the illness. They can catch the disease from being in close quarters with infected animals; coming into contact with humans who are wearing contaminated clothing or have been around ill animals; being transported in vehicles where contaminated animals were held; eating feed or hay tainted with diseased meat or other animal products; drinking tainted water; and being impregnated by an infected animal.
Overview
Once an animal has HMD, no treatment exists. The disease is not deadly, and the animals typically recover without medical intervention. HMD outbreaks should be contained quickly to reduce the spread to other animals. Many countries are prone to HMD outbreaks, and HMD remains a serious and common animal illness worldwide. Some of the areas with high numbers of HMD cases include Africa, Asia, Europe, the Middle East, and South America. Areas that do not have HMD cases include Australia, Central America, New Zealand, and North America. HMD has been eradicated from the United States since about 1929.
Because HMD is highly contagious, it can easily reenter many areas that do not have cases of HMD. Organizations in these countries, such as the United States Department of Agriculture, continue to take steps to ensure this does not happen. Some areas restrict or prohibit the import of animal products and by-products from areas known to have HMD cases.
Most countries have special protocols about how to deal with HMD-diseased animals. Some countries may quarantine infected animals and those that may have been in contact with ill creatures until all the animals have recovered from the disease—and no new outbreaks occur. In other countries, such as the United States, diseased animals and those that may have been exposed to infected creatures are euthanized, and their bodies are incinerated. Milk from infected cows can be safely rid of infection by heating it to at least 212 degrees Fahrenheit (100 degrees Celsius) for more than twenty minutes.
The animals' living quarters must be properly cleaned and disinfected. If any rodents or other vermin live in these areas, they must be euthanized to reduce spreading HMD. If any infected animals have been transported, the vehicles must undergo the same sterilization methods. New animals cannot be introduced into these areas until a specific amount of time has passed to ensure the virus has been killed and cannot infect more animals.
HMD vaccines exist, but they are specific to type and subtype. No universal HMD vaccine exists to protect all animals from all strains of the disease. During an outbreak, vaccines are used to help reduce the spread of certain types and subtypes of the disease. Animal-specific vaccines can help reduce the chance that a particular animal will contract HMD. These vaccines do not safeguard all animals or protect against all strains.
In May 2022, Indonesia experienced an HMD outbreak that soon surged to more than 450,000 cases by August of that year. At the time of the outbreak, the Jakarta Post reported that it was estimated to cause nearly US$1.37 billion in damage to the country's economy annually.
Bibliography
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