6. Virology II - PID

Pathogenicity

Pathogenicity

The ability of a Virus to cause disease in a host

pathogen

A virus that causes disease.

pathogenesis

The manner/mechanism of development of a disease.

Virulence

The quantitative or relative measure of the degree of pathogenicity of an infecting virus.

Avirulent

Not virulent.

is not

Virulence (IS/IS NOT) an absolute property of a virus.

variables

Virulence is dependent on many ________.

virus

Virulence is dependent on factors related to the ______, host, and other factors.

host

Virulence is dependent on factors related to the _______, virus, and other factors.

LD50

The dose of the virus required to cause death in 50% of animals.

more

A lower LD50 is a (MORE/LESS) virulent virus.

less

A higher LD50 is a (MORE/LESS) virulent virus.

A

Virus A has an LD50 of 15, while Virus B has an LD50 of 40. Virus (A/B) is more virulent

transcutaneous injection

Route of entry via a bite (by an arthropod or infected animal) or exposure to a contaminated needle.

viremia

Presence of a virus in the blood.

primary viremia

Initial entry of a virus into the blood

secondary viremia

Virus has replicated/multiplied in major organs and re-entered the blood stream.

disseminated infection

An infection that has spread beyond the primary site of infection.

systemic infection

An infection that has infected a number of organs or tissues.

nerves

Viruses can spread via _________ from the periphery, through receptors in the olfactory epithelium, or by crossing blood brain barrier.

neurotropic virus

A virus that can infect neural cells.

neuroinvasive virus

Virus that enters the CNS after infection of a peripheral site.

neurovirulent virus

A virus that causes disease of nervous tissue, manifesting as neurological symptoms and often death.

monocyte

A virus can use a ___________ as a "trojan horse" to cross blood-tissue barriers.

Viral tropism

The affinity of a virus for a particular host tissue

pantropic virus

Viruses that can replicate in more than one host organ/tissue.

after

Lysis occurs (BEFORE/AFTER) completion of viral replication.

before

Apoptosis occurs (BEFORE/AFTER) completion of viral replication.

oncovirus

Virus that can cause cancer

persistent infection

Some viruses do not cause immediate death of an infected host cell, but rather cause a ________ _________ that can result in low titer shedding for months to years.

immunosuppression

Some virus replication strategies result in atrophy or destruction of specific immune system cells, resulting in

acute

____________ infections usually result in intensive shedding over a short period.

persistent

___________ infections can result in shedding at low titers for months to years.

shedding

The release of infectious virions.

disseminated

Viral injury to the skin can be localized or __________.

localized

Viral injury to the skin can be disseminated or _________.

erythema

Reddening of the skin.

lytic

Term for destructing or bursting

Necrosis

Term for the death of body tissue

neuronophagia

The killing/devouring of neuronal cells by phagocytic cells

vacuoles

Bubbles found in cells

myelin

Material composing a sheath around nerves.

disseminated intravascular coagulation

Viral infection of the hemopoietic system can cause DIC:

teratogenic virus

Virus that causes developmental defects of embryo or fetus after in-utero infection.