Slow

Slow Virus Infection
Specialty	Neurology, Virology
Symptoms	Varies by disease
Duration	Long-term
Causes	Viruses
Diagnostic method	Diagnosis based on symptoms, medical imaging, laboratory tests
Treatment	Varies by specific virus

Slow virus infections are a subset of viral infections characterized by a long incubation period followed by progressive and often fatal disease. These infections are typically caused by unconventional viruses, such as prions, which induce chronic neurological diseases. The term "slow virus" was originally coined to describe these agents due to their prolonged incubation periods and the slow progression of the disease.

Characteristics

Slow virus infections are marked by their ability to establish a long-lasting infection in a host without causing immediate symptoms. After an incubation period that can last several years, the disease manifests with neurological symptoms that gradually worsen. Common characteristics include:

• Long incubation period
• Progressive neurological deterioration
• Lack of effective treatment and prevention methods

Examples

Some well-known diseases caused by slow viruses include:

• Subacute sclerosing panencephalitis (SSPE), linked to a persistent infection with a mutated form of the measles virus
• Progressive multifocal leukoencephalopathy (PML), associated with the JC virus in immunocompromised individuals
• Creutzfeldt-Jakob disease (CJD) and other prion diseases, which are transmissible spongiform encephalopathies

Diagnosis and Treatment

Diagnosis of slow virus infections is challenging due to the nonspecific nature of early symptoms and the long latency period. It typically involves:

• Clinical assessment of neurological symptoms
• Medical imaging techniques such as MRI
• Laboratory tests including serological and PCR assays for virus detection
• Biopsy in cases of prion diseases

Treatment options are limited and mostly focus on symptomatic relief and supportive care, as there are no curative treatments for most slow virus infections.

Prevention

Preventive measures are primarily aimed at controlling the spread of the causative agents and include:

• Vaccination where available, such as for measles to prevent SSPE
• Standard infection control practices in healthcare settings
• Public health measures to control animal diseases that may transmit viruses to humans

See also

• Virology
• Neurology
• Infectious disease