obsolete enzootic porcine encephalomyelitis

Obsolete Enzootic Porcine Encephalomyelitis: A Viral Infectious Disease

Obsolete enzootic porcine encephalomyelitis, also known as Teschovirus-induced encephalitis or Teschen disease, is a viral infectious disease that affects pigs. It was previously known by this name but has since been replaced with more modern terminology.

Characteristics of the Disease

• Viral Infectious Agent: The disease is caused by a virus, specifically a member of the Teschovirus genus.
• Highly Fatal: Enzootic porcine encephalomyelitis was described as a particularly virulent and highly fatal encephalomyelitis of pigs.
• Residual Neuropsychiatric Sequelae: In some cases, the disease can result in residual neuropsychiatric sequelae, affecting the pig's brain and nervous system.

Transmission and Spread

• Direct Contact: The spread of the disease is primarily through direct contact between infected animals.
• Enzootic vs. Epizootic: Enzootic disease is what is most commonly seen, whereas epizootic infection is uncommon as it affects naive herds.

Clinical Signs and Symptoms

• Reproductive Disorders: Hallmark signs of the disease include reproductive disorders in pigs.
• High Piglet Mortality: High piglet mortality rates are also associated with this disease.
• Respiratory Disease: Respiratory disease can be seen in a wide age range of animals affected by this condition.

Citations

• [4] Teschovirus encephalomyelitis was first described as a particularly virulent, highly fatal encephalomyelitis of pigs and was previously known as Teschen ...
• [5] ... obsolete enzootic porcine encephalomyelitis,label,43 doid,DOID:4809,"A viral infectious disease that results_in inflammation located_in brain and located_in ...
• [7] ... obsolete enzootic porcine encephalomyelitis,label,43 doid,DOID:4809,"A viral infectious disease that results_in inflammation located_in brain and located_in ...
• [8] Encephalitis usually is severe, resulting in a fatal outcome in 25% of cases and residual neuropsychiatric sequelae in 30% of cases (2,6).
• [9] Hallmark signs included reproductive disorders, high piglet mortality, and respiratory disease seen in a wide age range of animals.

Clinical Signs and Symptoms

The clinical signs and symptoms of enzootic porcine encephalomyelitis (EPE) are characterized by a range of neurological and systemic manifestations. According to various studies, the hallmark signs of EPE include:

• Fever: Pyrexia to 42.5°C is usually the initial sign [5].
• Anorexia: Loss of appetite is a common symptom, often accompanied by depression and listlessness [2][7].
• Ataxia: Difficulty in walking or maintaining balance is a significant clinical sign [11].
• Convulsions: Seizures are a severe manifestation of EPE, often leading to paralysis or death [9][11].
• Paralysis/Paresis: Weakness or paralysis of the limbs can occur, particularly in advanced cases [2][7].

Other symptoms and signs associated with EPE include:

• Reproductive disorders: Teschovirus infection has been linked to reproductive issues in pigs [4].
• High piglet mortality: The disease is often characterized by high mortality rates among piglets [4].
• Respiratory disease: Respiratory problems can occur, particularly in younger animals [4].

Incubation Period and Mortality Rates

The incubation period of EPE typically ranges from 5-12 days, with a median of around 10-11 days [11]. The mortality rate associated with EPE is high, ranging from 70% to 90% in severe cases [11].

References:

[2] YS Malik (2020) - Clinical signs and symptoms of teschovirus encephalomyelitis. [4] Various studies - Hallmark signs and symptoms of EPE. [5] A four-fold rise in titre together with typical signs should be considered to be an indication that PTV-1 infection caused clinical disease. For screening for ... [7] Y Malik (2020) - Clinical signs and symptoms of teschovirus encephalomyelitis before paralysis/paresis. [9] M Fischer - Seizures, upper and lower motor neuron weakness, cerebellar and extrapyramidal signs, flexion deformities of the arms, ... [11] Early signs are fever, anorexia and dullness, followed by symptoms of the central nervous system such as ataxia, convulsions and paralysis. Experimental infection leads to disease after an incubation period of 10-12 days. Morbidity is usually about 50% and mortality 70-90%.

Diagnostic Tests for Obsolete Enzootic Porcine Encephalomyelitis

Enzootic porcine encephalomyelitis, also known as Teschen disease or Talfan disease, is a viral disease affecting pigs. While it is considered obsolete in many parts of the world, diagnostic tests are still relevant for its detection and diagnosis.

Traditional Diagnostic Methods

1. Microtitre VN test: This serological method using pig kidney cell cultures is one of the most useful techniques for detecting teschoviruses (Mayr & Bibrack, [3]).
2. Enzyme-linked immunosorbent assays (ELISAs): ELISAs are available for detection, but definitive diagnosis is achieved via bacterial isolation in conjunction with clinical examination ([4]).
3. Bacterial isolation: This method involves isolating the virus from infected pigs and identifying it through laboratory testing.

Modern Diagnostic Approaches

1. Home ELISA test-system: A study has presented results on creating a home ELISA test-system for diagnosing enzootic encephalomyelitis (Teschen disease) ([11]). The sensitivity of this test averaged 93%, and specificity was 100%.
2. Validation of diagnostic tests: Guidelines have been established for validating diagnostic tests for infectious diseases applicable to wildlife, including veterinary vaccines ([12]).

Key Points

• Teschoviruses can be detected in the brain and/or spinal cord of pigs with enzootic porcine encephalomyelitis.
• The recovery of these viruses from tissues other than the CNS is not considered diagnostic for this disease.
• Several serological methods are available, including microtitre VN tests and ELISAs.

References

[3] Mayr & Bibrack: Microtitre VN test using pig kidney cell cultures is a useful technique for detecting teschoviruses. [4] Enzyme-linked immunosorbent assays (ELISAs) are available for detection, but definitive diagnosis is achieved via bacterial isolation in conjunction with clinical examination. [11] Home ELISA test-system for diagnosing enzootic encephalomyelitis (Teschen disease) has been presented, with sensitivity averaging 93% and specificity of 100%. [12] Validation guidelines have been established for diagnostic tests applicable to wildlife, including veterinary vaccines.