Porcine Enterovirus Infection Study Guide

Overview and Clinical Importance

Porcine enterovirus infections encompass a group of diseases caused by viruses in the family Picornaviridae, primarily affecting swine through several clinical syndromes. These viruses have been reclassified into three genera: Teschovirus (formerly PEV 1-7 and 11-13), Sapelovirus (formerly PEV-8), and Enterovirus G (formerly PEV 9-10). The most clinically significant is Porcine Teschovirus (PTV), which causes neurological disease ranging from mild ataxia (Talfan disease) to fatal polioencephalomyelitis (Teschen disease).

For the NAVLE, understanding this disease is essential because it involves multisystemic presentations including neurological, reproductive, enteric, and respiratory manifestations. The acronym SMEDI (Stillbirth, Mummification, Embryonic Death, Infertility) was originally coined for porcine enterovirus-associated reproductive failure, though porcine parvovirus is now considered the more common cause.

Etiology

Viral Classification and Characteristics

Key Viral Properties

• Non-enveloped, small (25-30 nm) icosahedral viruses
• Positive-sense single-stranded RNA genome (~7.1 kb)
• Extremely stable in environment: survives pH 2-9, resists heat and lipid solvents
• Persists greater than 5 months at 15°C; survives in liquid manure for prolonged periods
• Effective disinfectants: Sodium hypochlorite, 70% ethanol, sodium chlorite with heat

Epidemiology

Host Range and Distribution

Pigs (Sus scrofa) are the only known natural hosts, including domestic swine and wild boar. PTVs are ubiquitous in pig populations worldwide, with most infections being subclinical. Severe Teschen disease outbreaks have occurred in Europe (Czech Republic 1929, Haiti 2009, Canada 2011) and Africa (Madagascar). The disease is now rare in Western Europe but remains endemic in parts of Eastern Europe and Africa.