The Complete Guide to Tick-Borne Canine SFTS (Severe Fever with Thrombocytopenia Syndrome)

ImmunityDiseasesMeongsiljang Veterinary Advisory Board

Severe Fever with Thrombocytopenia Syndrome (SFTS) is a viral infection transmitted by the Haemaphysalis longicornis tick. It has a high fatality rate and can be transmitted to humans, so dog owners must be aware of it.

What is Canine SFTS?

A puppy diagnosed with tick-borne infection symptoms at a veterinary clinic

Canine SFTS (Severe Fever with Thrombocytopenia Syndrome) is an acute systemic infectious disease caused by the Dabie bandavirus (SFTS virus), which is transmitted by ticks. Although this virus was previously classified within the Bunyaviridae family, current textbooks classify it under the Phenuiviridae family. The most critical aspect is early recognition. If acute symptoms such as high fever, lethargy, gastrointestinal issues, or jaundice appear within a few days to about two weeks after a tick bite, you should visit an animal hospital immediately. As a zoonotic disease that has been reported to cause fatalities in humans and cats, and has also shown fatal outcomes in dogs, pet owners must also exercise caution.

How is it transmitted?

SFTS virus is transmitted through ticks, such as the Haemaphysalis longicornis tick. When a dog walks through grassy areas, bushes, or hiking trails, ticks can attach to its body and feed on its blood, potentially introducing the virus into the body. According to textbooks, many livestock and wild animals are primarily exposed to this virus through tick bites. Ticks are typically more active during warm seasons, so extra caution is needed when walking your dog during these times. Additionally, there have been reported cases of transmission to humans or other animals through direct contact with the blood or bodily fluids of infected animals, especially when these fluids come into contact with wounds or mucous membranes. Therefore, care should be taken when handling suspected infected animals.

Checklist of Main Symptoms of Canine SFTS

SFTS can be easily overlooked in its early stages because it often appears as simple lethargy. If two or more of the following signs occur simultaneously, SFTS should be suspected. - High fever: Sudden onset of fever lasting for several days - Severe lethargy: Refusal to eat and persistent weakness, with the pet lying flat and unable to get up - Vomiting and diarrhea: Sudden gastrointestinal symptoms, which may include bloody stools - Bleeding tendency: Gum bleeding, nosebleeds, or blood in the urine due to decreased platelet count - Anemia and weakness: Reduced energy levels caused by a drop in blood cells, including white blood cells and platelets (with possible bone marrow suppression) - Jaundice: Yellowing of the gums and the whites of the eyes

A veterinarian’s hand checking for pinpoint bleeding on the gums

Seek Immediate Veterinary Care for These Symptoms

Seek emergency veterinary care immediately if any one of the following signs is present. SFTS can progress rapidly, with severe thrombocytopenia and leukopenia leading to critical condition. - Tick bite marks within the past two weeks - High fever accompanied by lethargy or dull responsiveness - Bleeding symptoms such as epistaxis, hematuria, or melena - Pale or jaundiced gums - Seizures or collapse Pet owners should also wear a mask and gloves, and wash their hands thoroughly after contact.

How is it Diagnosed at the Veterinary Clinic?

Diagnosing SFTS based on clinical signs alone is challenging, so we use a combination of blood tests and molecular (genetic) testing. - Complete Blood Count (CBC): Characteristic findings include thrombocytopenia (low platelet count) and leukopenia (low white blood cell count). - Serum Biochemistry: Assesses organ involvement, such as jaundice, and evaluates overall systemic health. - PCR (Genetic) Testing: Detection of the virus's genetic material in blood or tissue samples serves as definitive evidence of active infection. - Additional Evaluation: We also investigate the underlying causes of cytopenia, such as bone marrow suppression. If you notice any tick bite sites, be sure to show them to your veterinarian. Always wear protective gear when handling samples.

How is Treatment Conducted?

There is currently no established antiviral treatment specifically for SFTS. Therefore, the cornerstone of management is supportive care aimed at alleviating symptoms and preventing complications. - Fluid therapy: Prevents dehydration and circulatory failure; requires hospitalization. - Blood transfusions: Consider whole blood or plasma transfusions if platelet and red blood cell counts drop severely. - Organ protection: Minimizes damage to vital organs such as the liver and kidneys. - Antibiotics: Prevents and treats secondary bacterial infections. - Isolation and hospitalization: Prevents transmission to caregivers and veterinary staff. The duration of treatment varies depending on the patient’s clinical condition, and outcomes are generally better with early, aggressive intervention. Your veterinarian will determine the appropriate dosage and administration schedule based on your pet’s weight and overall health status.

A dog receiving intravenous fluid therapy during hospitalization

Prevention and Management at Home

Prevention is the best defense against SFTS. According to veterinary dermatology textbooks, tick repellents containing various active ingredients are effective. - Regular use of tick preventatives: Administer spot-on or oral formulations containing ingredients such as fipronil or fluralaner at intervals of 4 to 12 weeks. - Full-body check after walks: Pay close attention to the ears, armpits, between the toes, and the groin area. - Avoid walking in grassy or bushy areas: This is especially important in dense vegetation from May to August. - Environmental management: Keep lawn grass short and remove fallen leaves. - If you find a tick: Do not pull it off with your hands; instead, use a tick remover to slowly and steadily extract it.

It Can Be Transmitted to Humans

Severe Fever with Thrombocytopenia Syndrome (SFTS) is a dangerous zoonotic disease that has been reported to cause fatalities in humans, cats, and dogs. Because direct contact with the blood or bodily fluids of an infected animal can transmit the virus to pet owners, extreme caution is essential. - If your dog shows suspected symptoms, avoid touching it with bare hands and wear disposable gloves and a mask. - When handling vomit or bloody stool, wear disposable gloves and disinfect the area with a diluted bleach solution (1:10 ratio). - If you develop a fever or muscle pain, inform your healthcare provider about your potential exposure to SFTS. Always wear protective gear, such as gloves, when removing ticks or handling samples.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Is there a vaccine for SFTS?

There is currently no widely available commercial vaccine for SFTS. The most practical preventive measures are regular administration of tick preventatives and careful management of your pet’s walking environment.

Does a tick bite always lead to SFTS?

Not exactly. The virus can only be transmitted if you’re bitten by a tick that’s already carrying it. The prevalence of infected ticks varies by region and season, so it’s important to watch for symptoms like fever and lethargy for about two weeks after a bite.

Can a fully recovered dog transmit the disease to other dogs?

Reports indicate that the virus can be detected in the bodily fluids of recovering animals for a period of time. To ensure safety, please adhere to the isolation period recommended by your veterinarian and only allow contact with other pets after your animal has been officially cleared as recovered.

Are dogs that live indoors also at risk?

Although the risk is low, ticks can hitch a ride indoors on your clothes or other pets. It’s a good idea to use preventive treatment even for short outings.

Can cats get SFTS?

Yes, cats can also become infected, and the condition can be so severe that fatalities have been reported in both humans and cats. However, some ingredients in tick preventives can be toxic to cats, so be sure to use a product specifically formulated for cats and consult with your veterinarian.

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References

[1] BSAVA Manual of Canine and Feline Dermatology, 4th Ed — Ectoparasite Control Chapter

[2] Principles and Practices of Canine and Feline Clinical Parasitic Diseases — Tick-borne Diseases Chapter

[3] 질병관리청, 중증열성혈소판감소증후군(SFTS) 관리지침, 2024