Teschovirus

Teschoviruses are emerging pathogens, belonging to the family Picornaviridae, and infects porcine population only. Among all, porcine teschoviruses (PTVs) are of high prominence leading to clinical illness and consequent economic loss to the livestock sector. These are associated with extremely lethal non-suppurative polioencephalomyelitis (Teschen disease) and are distributed world over. Its milder form, Talfan disease, inflicts low morbidity and mortality and general clinical disease. The first epizootics of Teschen disease occurred in 1929 in the Czech Republic. Mature virions are small (23–30 nm) and stable in environmental conditions (pH range 2–9, heat, lipid solvents). Genetic variations in the major surface protein, VP1, lead to the evolution of several new types. As of now, 13 genotypes in PTV are approved, namely PTV-1–13. Among all, PTV-1 is highly virulent and causes severe mortality and morbidity in the porcine population, domestic as well as wild. Ingestion is the main spreading route of infection, though intra-nasal infection and virus secretion in the urine are also noted. Along with encephalitis, PTVs are also responsible for reproductive disorders, diarrhoea, pneumonia, pericarditis and myocarditis. PTVs are also found as co-infection with several bacterial, viral and parasitic pathogens. Several conventional and modern diagnostics tools are available for their detection. Alternative of serological typing, VP1 and VP2 gene-based molecular typing is now preferred to know the epidemiological pattern. Although initially vaccines were used for its eradication in Europe, due to the sporadic reports of mild PTV infection in several countries, the approach was discontinued. Moreover, due to the presence of multiple serotypes, developing a multivalent PTV vaccine to protect against all strains is a major challenge.