How is West Nile Virus diagnosed in dogs and cats?

Your vet will typically collect blood or neural samples for PCR or antibody testing, interpreted alongside clinical signs and imaging findings. Discuss diagnostic options with your vet.

What is the treatment for West Nile Virus infection?

Treatment is primarily supportive care, including vital signs monitoring and symptomatic management. Hospitalisation or outpatient follow-up will be arranged based on your vet's assessment — ask your vet for specific management details.

How can West Nile Virus infection be prevented?

The key is reducing mosquito exposure: eliminate standing water, improve environmental mosquito control, and ask your vet for recommendations on home protection.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

West Nile Virus in Dogs & Cats: Neurological Symptoms, PCR Testing & Supportive Care [2025]

A mosquito-borne viral infection that can cause neurological signs such as seizures and paralysis; no specific antiviral exists and treatment is primarily supportive care.

Take 1 minute to check the symptoms first

Last updated: 2026/01/06

Pethealthmap Editorial Team

Sources: AVMA, CDC, National Taiwan University Veterinary Hospital

When to See a Vet

Seek emergency care immediately

•Sudden hind limb weakness with complete inability to stand
•Continuous full-body seizures lasting several minutes without stopping
•Onset of coma or severely impaired responsiveness that persists

Schedule a clinic visit soon (within 24–72 hours)

•Persistent weakness with noticeably reduced appetite lasting more than one day
•Repeated tremors or brief seizure episodes occurring multiple times
•Unsteady gait or difficulty standing but still able to walk short distances

01What symptoms indicate something is wrong?

West Nile Virus infection in dogs and cats can cause both neurological and systemic signs, ranging from mild discomfort to severe neurological abnormalities.

Generalised weakness and noticeably reduced activity
Reduced appetite or appearing unwilling to eat
Repeated trembling or muscle twitching (not caused by cold)
Unsteady gait, losing balance when standing or walking
Seizures or involuntary muscle contractions
Partial or generalised flaccid paralysis with restricted movement

Seek emergency care immediately if you notice the following symptoms:

⚠️ Sudden hindlimb paralysis with complete loss of mobility
⚠️ Continuous seizures that cannot be stopped
⚠️ Loss of consciousness or severe disorientation

02How to assess the situation at home: what to monitor and when to go to the emergency vet

Careful observation and logging of changes at home helps your vet quickly understand the progression and identify the right diagnostic priorities.

Note the time symptoms first appeared and how they have progressed
Track daily changes in food and water intake
Video any episodes of unsteady walking, trembling, or seizures for your vet to review
Observe and log the frequency and any abnormalities in urination and defecation
Note the frequency, duration, and any triggers of trembling or shaking
If symptoms worsen, contact your vet immediately to arrange an assessment

03How will the vet diagnose this? Common diagnostic tests

Your vet will combine a physical examination with laboratory and imaging tests to confirm whether the signs are related to viral infection or another condition.

Full physical examination with a focus on the neurological system and general vital signs

Blood and biochemistry panel

assessing organ function and inflammatory markers

Urinalysis

to rule out urinary or metabolic issues

PCR or antibody testing

detecting viral nucleic acids or immune response to support diagnosis

CT or MRI if needed to evaluate central nervous system lesions

Referral to a facility with PCR testing and advanced imaging capabilities is recommended

04What comes after diagnosis? Treatment, diet adjustments, and home care guide

Treatment is primarily supportive care; hospitalisation for monitoring may be required depending on severity, along with scheduled follow-up to assess recovery.

Inpatient or outpatient supportive care with vital signs monitoring
Symptomatic management and scheduled recheck appointments based on condition
Maintaining hydration and nutrition, with feeding method adjusted if necessary
Keep the home environment quiet, minimise stimulation, and allow the pet to rest fully
Follow your vet's schedule for periodic blood tests or imaging to track recovery
If recovery is slow, consider referral to an infectious disease or neurology specialist

05What to prepare before the vet visit: key information to help your vet work faster

Write down when symptoms started and how they have changed over time

List all current medications, vaccines, and supplements

Bring notes on eating and toilet habits

Use your phone to record any seizures, gait abnormalities, or unsteadiness for the vet

Bring any previous test results or discharge summaries if available

For urgent or severe cases, book ahead at a specialist hospital with PCR testing capability

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.