SAT-1 FOOT-AND-MOUTH DISEASE: SIGNS, TRANSMISSION ROUTES, TREATMENT, AND EFFECTIVE PREVENTION

SAT-1 Foot-and-mouth disease is one of the most dangerous serotypes of the foot-and-mouth disease virus affecting cloven-hoofed animals such as buffaloes, cattle, pigs, goats, and sheep (according to the Department of Livestock Production and Animal Health). This strain can spread rapidly and cause significant losses in productivity, reproduction, and disease control costs if not detected early.
In the context of increasingly complex cross-border disease risks, livestock producers need to clearly understand what SAT-1 is, how the disease spreads, its clinical signs, diagnostic methods, how to respond when an outbreak is suspected, and the most effective prevention measures. In this article, the Fivevet Field Technical Department summarizes important information to help farm owners proactively respond to SAT-1 foot-and-mouth disease. 1. What is SAT-1 Foot-and-Mouth Disease?
According to the Department of Livestock Production and Animal Health, foot-and-mouth disease is a highly contagious disease caused by a virus belonging to the genus Aphthovirus and the family Picornaviridae. The virus causes characteristic symptoms such as blisters and ulcers in and around the mouth, nose, teats, and feet of affected cattle.
The foot-and-mouth disease virus has 7 serotypes: O, A, C, Asia 1, SAT-1, SAT-2, and SAT-3. Each serotype also contains multiple different subtypes. Therefore, accurate identification of the virus type is essential for disease surveillance and selecting appropriate vaccines.
The foot-and-mouth disease (FMD) virus is a positive-sense single-stranded RNA virus containing approximately 8,000 nucleotides and four major structural proteins: VP1, VP2, VP3, and VP4. Among these, the VP1 gene region has a high mutation rate and plays an important role in the virus’s genetic variation and antigenic properties.
SAT-1 stands for Southern African Territories type 1. To date, Vietnam has recorded the presence of serotypes O, A, and Asia 1. Although the SAT-1 serotype has not yet been detected in Vietnam, it remains a potential threat that requires close monitoring due to the risk of introduction from external sources.
How Dangerous Is SAT-1?
SAT-1 has a broad host range and can infect many cloven-hoofed animals such as buffaloes, cattle, pigs, goats, and sheep. It may also occur in camels, deer, and several other hoofed animals.
The danger of SAT-1 lies not only in its rapid transmission but also in its long-term impacts on livestock herds. Infected animals often develop high fever, reduced appetite, rapid weight loss, decreased reproductive performance, a significant drop in milk production in dairy cattle, and an increased risk of myocarditis complications in young animals.
The level of damage caused by the disease is highly concerning. In adult buffaloes and cattle, the mortality rate may range from 5–10%, but it can increase to 20–50% in calves depending on their health status. In pigs, the mortality rate in adults is around 20%, while in piglets it can reach 50–80% due to severe damage caused by the virus to the heart and respiratory system.
In addition to direct losses from mortality and reduced productivity, the disease also increases treatment costs, labor and care expenses, disinfection costs, prolongs recovery time, and negatively affects the transportation, trading, and marketing of animal. Transmission Routes of SAT-1 Foot-and-Mouth Disease
The SAT-1 virus can spread very rapidly through both direct and indirect transmission routes. The main modes of transmission are through the digestive tract, respiratory tract, and direct contact between infected and healthy animals.
Sources of the virus include saliva, vesicular fluid, milk, urine, feces, semen, exhaled air from infected animals, as well as contaminated meat and internal organs. The virus can also spread indirectly through farming equipment, caretakers, transport vehicles, livestock waste, wastewater from animal housing, and contaminated feed and drinking water.
Under favorable conditions, the virus may also spread through the air by wind, greatly increasing the speed of transmission within affected areas.
2. Clinical Signs of SAT-1 Foot-and-Mouth Disease in cattle
Incubation Period
The incubation period is typically 3–6 days. In some cases, it may range from 2–14 days depending on the animal species, immune status, and the amount of virus exposure.
Typical Clinical Signs of SAT-1 Foot-and-Mouth Disease
Infected animals commonly show high fever (40–41°C), fatigue, reduced appetite, or complete loss of appetite. In buffaloes and cattle, excessive salivation is often observed, with thick, white, foamy saliva hanging in long strands around the mouth.
Affected animals develop vesicles (blisters) on the tongue, lips, gums, upper jaw, nostrils, around the teats, coronary bands, and interdigital spaces. As these vesicles enlarge and rupture, painful ulcers form, making animals highly susceptible to secondary infections. This results in difficulty eating, rapid weight loss, and slow recovery.
Another characteristic sign is difficulty walking or lameness. Small red lesions may first appear around the coronary band, later developing into widespread vesicles that can lead to hoof separation or hoof loss, especially in piglets. Clinical Signs in Different Animal Groups
In buffaloes and cattle:
Excessive salivation is commonly observed, with thick white saliva resembling soap foam and forming long strands around the mouth. Clear vesicles develop in the oral cavity, accompanied by inflammation and ulceration of the oral mucosa, reduced rumination, decreased feed intake, and lower milk production.
In pigs:
Lesions on the feet are usually more prominent. Affected pigs often show lameness, foot pain, reluctance to stand, prolonged lying, and may experience hoof separation or hoof loss.
In young animals:
Young livestock may die suddenly due to myocarditis, even when lesions in the mouth and hooves are not yet clearly visible.
3. Diagnosis of SAT-1 Foot-and-Mouth Disease
Clinical Diagnosis
The disease can be suspected based on characteristic signs such as sudden high fever, vesicles on the mouth, feet, and teats, excessive salivation, loss of appetite, and difficulty walking. However, diagnosis should not rely solely on clinical signs, as the disease may be confused with other conditions that also cause lesions in the mouth or feet.
Lesions Observed During Necropsy
During necropsy of infected animals, lesions such as vesicles and ulcers in the mouth, on the feet, and around the teats may be observed. Ulceration and inflammation of the tongue mucosa and digestive tract can also occur, along with myocarditis in young animals.
Laboratory Diagnosis
RT-PCR Testing
This method is used to detect FMD viral RNA in clinical samples such as blood, vesicular fluid, mucosal swabs, or organ tissues collected from suspected animals.
ELISA Testing
ELISA is used to detect antibodies against the FMD virus in blood samples, helping evaluate infection status or the immune response of livestock.
Virus Isolation
This method is performed to isolate, identify, and determine the serotype of the FMD virus, supporting disease diagnosis, epidemiological surveillance, and the selection of appropriate prevention measures.
4. What Should Be Done When SAT-1 Is Suspected?
When livestock show signs of suspected SAT-1 foot-and-mouth disease, immediate action is required to limit the spread within the herd and surrounding areas.
Isolate suspected animals immediately:
Separate infected or suspected animals from healthy ones, minimize direct contact, and restrict the movement of people into and out of the farming area.
Stop livestock movement:
Do not transport suspected animals out of the farm, do not sell infected animals, and avoid unauthorized slaughtering.
Implement thorough cleaning and disinfection:
Animal houses, floors, exercise areas, feeding and watering areas, farming equipment, transport vehicles, as well as caretakers’ clothing and footwear should be cleaned and disinfected regularly to break the transmission route of the virus.
Provide appropriate supportive care:
Currently, there is no specific treatment for foot-and-mouth disease. Management mainly focuses on symptomatic treatment and supportive care, including fever reduction, pain relief, anti-inflammatory support, disinfection of ulcers, immune support, control of secondary bacterial infections, and providing soft, easily digestible feed along with clean drinking water.
Report immediately to veterinary authorities:
When an outbreak is suspected, farmers should promptly notify veterinary officers for sample collection, laboratory testing, accurate diagnosis, outbreak containment, and proper disease control measures.
Supportive Treatment and Herd Care
Supportive treatment should be carried out under the guidance of a veterinarian. Depending on the condition of the affected herd, measures may include fever and pain control, anti-inflammatory treatment, cleaning and disinfecting lesions, strengthening immunity, controlling secondary bacterial infections, and providing appropriate care for different animal groups.
Because the health of infected animals is significantly weakened, with multiple open lesions and a high risk of disease spread, supportive care must be carried out carefully, comprehensively, and appropriately according to each stage of the disease to help animals recover more effectively.
- Antipyretic and analgesics: Products such as Five-Mexicam, Five-Metamax.50, Five-Ketofen, Five-Flunixin, Five-Tofen@LA, ... may be used.
- Disinfect the ulcer: Disinfectant solutions should be used to clean ulcers in the mouth and on the feet. Products such as Five-Iodine can be applied directly to the wounds, while Five-CTC Spray may be sprayed onto cleaned lesion areas after proper sanitation.
- Immune support and control of secondary infections: using one of the products such as Five-Cefketo Plus, Five-Cetifor Inj, Five-Cfor, Five-Amox@.LA, Five-PenStrep.LA, and Five-Oxylin.LA. These may be combined with supportive supplements such as Five-Butasal, Five-Acemin.B12, Five-Cafein,... 5. Effective Prevention of SAT-1 Foot-and-Mouth Disease
Vaccination with the Correct Strain and Proper Schedule
Currently, there is no commercially available vaccine for mass vaccination against SAT-1 foot-and-mouth disease. Therefore, livestock producers should proactively protect their herds against other circulating FMD virus serotypes by following recommended vaccination schedules and using vaccines approved by veterinary authorities. When FMD is suspected, farmers should immediately notify veterinary authorities for sample collection, virus serotyping, and timely disease control measures.
The following vaccination schedule for FMD serotypes currently circulating in Vietnam (O, A, and Asia 1) may be used as a reference:
- Buffaloes and cattle: The first vaccination should be administered to calves from 2 weeks of age onward, followed by a booster dose after 4 weeks. Revaccination should then be carried out every 6 months.
- Pigs: The first vaccination should be given from 2 weeks of age onward, followed by a booster after 4 weeks. Thereafter, breeding sows and boars should be revaccinated every 6 months. In particular, sows should receive a booster 2–3 weeks before farrowing to enhance passive immunity in piglets.
- Goats and sheep: The first vaccination should be administered from 2 weeks of age onward, followed by a booster after 4 weeks, then revaccinated once a year. Booster doses should use the same vaccine type as the initial vaccination according to veterinary recommendations.
Epidemiological Control and Biosecurity
- Strict control should be applied to people, transport vehicles, and farming equipment entering and leaving the farm area. Livestock from outbreak areas should not be transported, traded, or slaughtered, and the introduction of animals with unclear origins should be avoided.
- Newly introduced animals should undergo health checks, and necessary laboratory testing should be performed when there is suspicion of disease risk. These animals should be quarantined for at least 21 days before being officially introduced into the herd.
Cleaning and sanitation of animal housing, and management of feed and drinking water.
- Animal housing, farming equipment, playgrounds, and grazing areas should be cleaned and disinfected regularly. In addition, insects and rodents should be controlled as they may act as disease vectors. Manure, livestock waste, and dead animals must be disposed of properly in accordance with regulations.
- To eliminate pathogens in the farming environment, some disinfectant products such as Five-Iodine, Five-B.K.G, Five-BGF, and Five-Perkon 3S can be used periodically. In addition, insect control products such as Five-Tox 250, Five-Cymethrin, Five-Permethrin, and Five-Larva Kill can be used in combination.
- In addition, clean feed and drinking water should be provided, free from contamination and disease-causing pathogens. Leftover feed from disease-affected areas must not be used. The diet should be nutritionally balanced, appropriate in type, and suitable for each animal species and age group in order to maintain the herd’s immunity and resistance.
- Full vaccination according to the recommended schedule and field strain, combined with proper care, good nutrition, and strict biosecurity measures, is currently the most effective solution for preventing Foot-and-Mouth Disease.
- Foot-and-Mouth Disease is a major threat to the livestock industry due to its rapid spread, severe lesions, and negative impact on production efficiency. Early recognition of clinical signs, strict implementation of biosecurity measures, proper control of animal introduction, vaccination according to the recommended program, and timely reporting to veterinary authorities are important measures to protect livestock herds.
The earlier farmers detect the disease and apply proper control measures from the beginning, the lower the risk of economic losses.
This article was prepared by the Field Technical Department of Fivevet.
Frequently Asked Questions
1. What is SAT-1 Foot-and-Mouth Disease?
Foot-and-Mouth Disease SAT-1 is a serotype of the Foot-and-Mouth Disease virus that can infect many cloven-hoofed animals such as buffaloes, cattle, pigs, goats, and sheep. It is considered a dangerous strain due to its rapid transmission and potential to cause severe economic losses in livestock production.
2. Has SAT-1 been detected in Vietnam?
At present, Vietnam has mainly reported the O, A, and Asia 1 serotypes. The SAT-1 serotype has not yet been officially detected; however, it remains a potential threat that requires close monitoring because of the risk of introduction from outside the country.
3. Which animals can be infected by SAT-1?
All cloven-hoofed animals are at risk of infection, most commonly buffaloes, cattle, pigs, goats, and sheep. In addition, this strain may also affect some other hoofed animals.
4. What should be done first when SAT-1 is suspected?
When an outbreak is suspected, sick or suspected animals should be isolated immediately, livestock movement must be stopped, and the farming area should be cleaned and disinfected thoroughly. Farmers should also promptly notify veterinary authorities for guidance on sampling, diagnosis, and proper outbreak management procedures.
5. How can SAT-1 Foot-and-Mouth Disease be effectively prevented?
The most important preventive measure is full vaccination according to the recommended schedule and field strain, combined with strict biosecurity practices, proper control of new animal introduction, regular cleaning and disinfection of animal housing, and providing clean feed and drinking water for animal.