Encephalomyocarditis Virus Infection in Pigs
- See your vet immediately if a pig has sudden collapse, severe breathing trouble, trembling, staggering, or if multiple pigs die unexpectedly.
- Encephalomyocarditis virus, or EMCV, is a rodent-associated viral disease that most often damages the heart in pigs and can also cause late-pregnancy abortions, stillbirths, and mummified fetuses.
- Young pigs can die very quickly, sometimes before obvious warning signs are noticed. In older pigs, losses may be lower but outbreaks can still be serious.
- There is no specific antiviral treatment. Care focuses on confirming the cause, reducing stress, supporting affected pigs when possible, and tightening rodent control and biosecurity.
- A practical diagnostic cost range in the US is about $200-$700+ per case or outbreak workup, depending on whether your vet recommends farm call fees, necropsy, PCR, histopathology, and herd-level testing.
What Is Encephalomyocarditis Virus Infection in Pigs?
Encephalomyocarditis virus infection is a contagious viral disease of pigs caused by a cardiovirus in the Picornaviridae family. Even though the name mentions the brain and heart, the most important problem in pigs is usually damage to the heart muscle, which can lead to heart failure, fluid in the lungs, and sudden death.
EMCV has been reported in pigs around the world and is strongly linked to wild rats and mice. Rodents can shed the virus in urine and feces, contaminating feed, water, and the pig environment. In pig herds, the first clue may be unexpected deaths in piglets or growers, or reproductive losses in sows.
This infection can affect pigs of any age. Suckling pigs may have very high death loss, while older pigs may have lower mortality. In breeding herds, EMCV can also cross the placenta and contribute to late-term abortions, stillbirths, fetal mummification, and reduced farrowing success.
Because several other swine diseases can look similar, your vet usually needs lab testing to confirm EMCV. Fast action matters, especially when there is sudden death or herd-level reproductive loss.
Symptoms of Encephalomyocarditis Virus Infection in Pigs
- Sudden death
- Breathing difficulty or open-mouth breathing
- Fever
- Anorexia or reduced feed intake
- Listlessness or weakness
- Trembling or staggering
- Paralysis or collapse
- Late-term abortions, stillbirths, or mummified fetuses
See your vet immediately if a pig collapses, struggles to breathe, or if you notice multiple sudden deaths in a group. EMCV can move fast, and young pigs may die before many signs are seen.
Call your vet promptly for late-pregnancy abortions, stillborn litters, or mummified fetuses, especially if rodent activity has increased around feed storage or housing. These signs are not specific to EMCV, so a timely herd investigation is the safest next step.
What Causes Encephalomyocarditis Virus Infection in Pigs?
EMCV infection in pigs is usually linked to spillover from infected rodents, especially rats and mice. Rodents can shed the virus in urine and feces, which then contaminate feed bins, feeders, water sources, bedding, and barn surfaces. Pigs may also be exposed by ingesting dead or dying rodents.
After pigs become infected, they can shed virus in nasal secretions and feces for a short period, which means pig-to-pig spread can happen through direct contact. Even so, rodent exposure is considered the key driver in many outbreaks.
The virus is also environmentally hardy. It can remain infectious for weeks to months under adverse conditions, which makes cleanup and prevention more challenging than with some fragile viruses.
Outbreak risk often rises when rodent populations increase, feed is easy for rodents to access, carcass disposal is delayed, or biosecurity slips. Stress and excitement may worsen losses in exposed pigs, so your vet may recommend handling changes while the herd is being evaluated.
How Is Encephalomyocarditis Virus Infection in Pigs Diagnosed?
Your vet will usually start with the history, age group affected, pattern of sudden deaths, reproductive losses, and rodent exposure risk. EMCV cannot be confirmed by signs alone because other swine problems can also cause sudden death, myocarditis, abortions, or weak piglets.
A strong diagnosis usually depends on necropsy and laboratory testing. In pigs that die acutely, the heart may show pale, linear, circular, or hemorrhagic areas, and fluid buildup may be present in the chest or lungs. However, these findings are not unique to EMCV, so your vet may submit heart, liver, kidney, spleen, brain, or fetal tissues for testing.
Definitive testing may include PCR, virus isolation, and sometimes immunohistochemistry. Merck notes that heart, liver, kidney, and spleen from acutely dead pigs or aborted fetuses are preferred samples for virus isolation, and EMCV can also be detected in porcine heart tissue by PCR. Single antibody tests are usually less helpful because subclinical exposure can occur.
For budgeting, a porcine necropsy at one US veterinary diagnostic lab is listed at $160 plus a $10 accession fee, and EMCV PCR is listed at $30 while EMCV virus isolation is $50. That puts a basic necropsy-plus-EMCV test combination around $200-$220 before shipping, farm call fees, and any added herd testing. Your vet can help choose the most useful samples and the most practical testing plan.
Treatment Options for Encephalomyocarditis Virus Infection in Pigs
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Urgent exam or herd consultation with your vet
- Isolation of visibly affected pigs when practical
- Stress reduction, quiet handling, and close monitoring
- Basic supportive care directed by your vet
- Focused rodent control and feed-storage cleanup
- Limited diagnostics such as selected necropsy or a small number of PCR submissions
Recommended Standard Treatment
- Farm visit or clinic consultation with full herd history review
- Necropsy of fresh deaths plus targeted PCR and pathology
- Supportive care plan for sick pigs as advised by your vet
- Review of breeding losses, abortion timing, and affected age groups
- Structured rodent control program
- Biosecurity review for feed, water, carcass disposal, and traffic flow
- Short-term monitoring plan for additional deaths or reproductive events
Advanced / Critical Care
- Comprehensive herd outbreak investigation
- Multiple necropsies and expanded tissue testing
- Broader differential testing for other reproductive, neurologic, or sudden-death diseases
- Detailed pathology review and possible outside-lab confirmation
- Intensive nursing and individualized supportive care for valuable pigs when feasible
- Formal biosecurity redesign and aggressive rodent exclusion measures
- Follow-up herd surveillance and repeat testing if your vet recommends it
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Encephalomyocarditis Virus Infection in Pigs
Bring these questions to your vet appointment to get the most out of your visit.
- Based on my pigs' ages and signs, how strongly do you suspect EMCV versus other causes of sudden death or reproductive loss?
- Which pigs or fetuses should be submitted for necropsy and PCR to give us the best chance of a diagnosis?
- What samples do you want collected, and how should they be stored or transported before they reach the lab?
- What level of supportive care is realistic for the pigs that are still alive, and what signs mean they need urgent reassessment?
- What rodent-control steps should we start today around feed, water, bedding, and building entry points?
- Do we need to change handling, movement, breeding plans, or group housing while we wait for test results?
- Are there other diseases you want to test for at the same time because the signs overlap with EMCV?
- What is the most practical cost range for diagnosis and herd prevention in our specific setup?
How to Prevent Encephalomyocarditis Virus Infection in Pigs
Prevention centers on rodent control. EMCV is strongly associated with rats and mice, so the most important step is reducing rodent access to feed, water, bedding, and housing. Store feed in rodent-resistant containers, clean up spills quickly, remove clutter, and seal entry points where possible.
Good carcass disposal also matters. Prompt removal and proper disposal of dead pigs can reduce contamination and may lower the chance of ongoing exposure. Your vet may also recommend reviewing traffic patterns, equipment sharing, and sanitation practices if there has been an outbreak.
Because EMCV can stay infectious in the environment for weeks to months, cleaning should be paired with an appropriate disinfectant program. Merck notes the virus can be inactivated by heat at 60°C for 30 minutes and by disinfectants containing chlorine or iodine when used correctly on production-animal premises.
There is no widely available commercial EMCV vaccine for routine swine use in the US. Autogenous products may exist in limited situations, but prevention usually relies on biosecurity, rodent management, and fast veterinary investigation of sudden deaths or reproductive losses.