DNA Viruses 2 (poxviruses)

What type of genome do poxviruses have?

Enveloped, double-stranded DNA.

Where do poxviruses replicate?

In the cytoplasm, unlike most DNA viruses.

What type of inclusion bodies do poxviruses produce?

Intracytoplasmic inclusion bodies.

What is the basic pathogenesis of poxvirus infection?

Viral proteins stimulate epidermal proliferation, producing raised lesions; endothelial infection causes vasculitis.

What is the typical progression of poxvirus skin lesions?

Raised skin lesions that progress to scabs.

What are the main transmission routes for poxviruses?

Aerosol, direct contact, and mechanical transmission by insects.

How does systemic poxvirus infection differ immunologically from local infection?

Systemic infection produces lifelong immunity; local infection produces transient immunity, so recurrence is possible.

Which poxvirus group causes generalized infection and characteristic skin lesions in cattle, sheep, and goats?

Capripoxviruses.

Which diseases are caused by capripoxviruses?

Lumpy skin disease in cattle, sheeppox, and goatpox.

What are key features of capripoxvirus infections?

Generalized infection with characteristic skin lesions; these are foreign animal diseases eradicated from the United States.

What is lumpy skin disease?

A capripoxvirus disease of cattle causing characteristic skin lesions and potentially systemic involvement.

What respiratory lesions can occur with lumpy skin disease?

Proliferative bronchiolitis and type II pneumocyte hyperplasia.

What is the primary presentation of swinepox?

Mild skin disease.

How is swinepox transmitted?

By the pig louse.

What are parapoxviruses notable for regarding zoonotic transmission?

All parapoxviruses are transmissible to humans.

What is orf, and which animals does it affect?

A parapoxvirus infection affecting young sheep, with lesions around the muzzle and lips.

What is bovine papular stomatitis, and which animals does it affect?

A parapoxvirus infection of young calves causing lesions on the muzzle, tongue, and esophagus.

What is pseudocowpox, and where are its lesions commonly found?

A parapoxvirus infection with lesions commonly found on the teats; it can cause milker's nodules in humans.

Which poxvirus causes milker's nodules in people?

Pseudocowpox virus.

How do orf, bovine papular stomatitis, and pseudocowpox differ?

Orf: young sheep, muzzle and lips; bovine papular stomatitis: young calves, muzzle, tongue, and esophagus; pseudocowpox: teat lesions and human milker's nodules.

What are the major similarities between poxvirus infections in domestic animals?

Epidermal proliferation, raised lesions progressing to scabs, and possible vasculitis.

Which poxvirus group is especially associated with systemic disease in ruminants?

Capripoxviruses.

Which poxvirus group is transmissible to humans?

Parapoxviruses, including orf, bovine papular stomatitis, and pseudocowpox viruses.

What is the key difference between parvovirus and poxvirus replication?

Parvoviruses replicate in nuclei of rapidly dividing cells; poxviruses replicate in the cytoplasm.