Key takeaways 

  • Foot-and-Mouth Disease (FMD) is highly contagious and rapidly transmitted between pigs via aerosols, contact and contaminated equipment. 
  • In pigs, the disease often causes severe lameness, vesicular lesions, and appetite loss. 
  • Serotype O remains the dominant global threat, particularly in Asia and Eastern Europe. 
  • Recent research confirms the high efficacy of inactivated and recombinant vaccines, though immunity may be delayed in piglets due to maternal antibodies. 
  • Biosecurity, early diagnosis, and outbreak zoning are vital tools in disease control, especially where FMD is not endemic. 

What is Foot-and-Mouth Disease (FMD)? 

FMD is a severe, transboundary viral disease caused by Aphthovirus (Picornaviridae), affecting all cloven-hoofed animals. It is characterised by fever, blisters in the mouth and on feet, and high contagiousness. Though FMD is often associated with cattle, pigs play a central role in amplifying the virus through massive aerosol shedding – making their management crucial to any control programme. 

There are seven serotypes of FMD virus (O, A, C, Asia 1, SAT 1, SAT 2, SAT 3). No cross-protection exists, requiring strain-specific vaccine formulations. 

Recognising the clinical signs of Foot-and-Mouth Disease in pigs 

The disease manifests with: 

  • High fever (40-41.5°C) 
  • Sudden onset of lameness; pigs may lie down and avoid walking 
  • Vesicles and erosions on snout, tongue, coronary band, and interdigital space 
  • Profuse salivation (“ropey saliva”) due to oral lesions 
  • Reduced feed intake and growth rates 
  • High piglet mortality due to myocarditis (“tiger heart” lesions) 

Symptoms in pigs may resemble those of swine vesicular disease or vesicular stomatitis. Laboratory confirmation is essential. 

Transmission routes & on-farm risk factors of Foot-and-Mouth Disease

FMD is one of the most contagious livestock diseases. Transmission pathways include: 

  • Direct contact between animals 
  • Indirect contact via people, clothing, vehicles, and equipment 
  • Airborne transmission – pigs emit virus particles in high concentrations 
  • Contaminated feed, especially raw meat or swill 
  • Semen or embryos from infected animals 

High-risk environments include: 

  • Mixed-species farms 
  • Markets and transport hubs 
  • Low vaccination coverage in endemic zones 
  • Poor enforcement of movement restrictions 

Global epidemiology 2023-2025 – Key outbreaks & serotypes of Foot-and-Mouth Disease 

FMD continues to affect regions with incomplete vaccination or weak veterinary infrastructure: 

  • Asia: SEACFMD (2024) reports 248 pig-related outbreaks, with Indonesia accounting for 111 (all serotype O). 
  • Africa: SAT 2 remains dominant in endemic countries, with spillover into pig populations in Uganda and Nigeria. 
  • Europe: Serotype O reappeared in Slovakia, Hungary, and Germany in 2025, linked to illegal meat imports and wild boar. 
  • South America: Brazil, nearing full “vaccination-free” status, remains under watch following isolated cases near borders. 

Global spread is largely dominated by serotype O, known for rapid transmission and environmental resilience. 

Economic burden of Foot-and-Mouth Disease for smallholders vs. large-scale systems 

  • Smallholder producers face catastrophic losses when FMD hits – depopulation, trade bans, and lack of compensation often drive families out of pig farming. 
  • Large commercial systems suffer from export restrictions, movement controls, and long-term loss of consumer confidence. 
  • The 2010 FMD outbreak in South Korea resulted in over 3 million pigs culled and US$2.6 billion in losses. 

Preventative vaccination and early containment are far less costly than managing full-blown outbreaks. 

Vaccination in pigs – efficacy benchmarks, schedules & interference 

Efficacy benchmarks 

  • Inactivated vaccines for serotype O demonstrate ~88% protection in pigs. 
  • Recombinant Ad5-based vaccines, especially when combined with porcine IFN-ω, achieved full protection within 24 hours post-vaccination. 

Schedules 

  • First dose: 6-8 weeks of age in non-endemic areas, or as early as 4 weeks in endemic regions 
  • Booster: at 3-4 weeks post-primary dose, then every 4-6 months 
  • Pregnant sows: vaccination 3-4 weeks pre-farrowing can enhance maternal antibody transfer 

Maternal antibody interference 

Colostral antibodies may reduce vaccine response if piglets are immunised too early. Piglets vaccinated <6 weeks old often show lower seroconversion; a delayed booster or second dose may be required to achieve full protection. 

Take-home messages for 2025 concerning Foot-and-Mouth Disease

  • Pigs are central to FMD spread and control due to their virus amplification capacity. 
  • Vaccines are effective but must be correctly timed and strain-matched. 
  • Biosecurity and rapid diagnostics remain the only defences in disease-free zones. 
  • Control strategies must target both backyard farms and industrial operations. 

Global occurrence of FMD in pigs 

FMD remains entrenched in parts of Asia, Africa, and South America. In 2025, Brazil awaits recognition as “FMD-free without vaccination.” Meanwhile, Europe witnessed fresh incursions via wild boar and illegal imports. Southeast Asia – particularly Indonesia, Myanmar, and Vietnam – continues to report high pig case numbers dominated by serotype O. Countries such as Australia, New Zealand, and the United States remain free from FMD, but risk pathways (e.g. illegal meat, migratory wildlife) require constant vigilance. 

FAQ: Foot-and-Mouth Disease in pigs 

What is the incubation period of FMD in pigs? 

FMD typically incubates in pigs for 2 to 4 days, though this can extend to up to 14 days depending on virus strain and exposure level. During this silent phase, animals may already begin to shed virus – particularly troubling in intensive systems where detection is delayed. 

Can vaccinated pigs still carry FMD virus? 

Yes. Vaccinated pigs can be sub-clinically infected, especially if exposed shortly after immunisation or when vaccine–strain matching is imperfect. Though pigs don’t appear to become persistent carriers like cattle, short-term excretion of virus is still possible –e nough to spread infection under dense conditions. 

How soon after vaccination is immunity achieved? 

Inactivated vaccines generally confer protective antibody levels within 7-10 days. However, new adenovirus-vectored vaccines show near-immediate protection (within 24 hours) when used alongside porcine interferon-ω. Achieving full herd protection, however, depends on proper booster schedules and vaccine coverage above 80%. 

Does maternal antibody interfere with piglet vaccination? 

Yes. Maternal antibodies passed via colostrum can neutralise vaccine antigens, making early vaccination ineffective. Studies recommend delaying initial vaccination to 6–8 weeks of age or using a booster protocol if early vaccination is necessary in endemic areas. 

Which disinfectants reliably inactivate FMD virus on farm equipment? 

WOAH-approved disinfectants include: 

  • 2% sodium hydroxide (NaOH) 
  • 4% sodium carbonate 
  • 0.2% citric acid 
    All require a minimum contact time of 30 minutes on cleaned, non-porous surfaces. Organic matter can block disinfection, so pre-washing is critical. 

Are there genetic lines of pigs resistant to FMD? 

No definitive resistance has been identified among domestic pig breeds. While genetic factors may influence disease severity, all pigs are susceptible to FMD infection and should be managed with consistent biosecurity, regardless of breed.