Viral transmission and spread in the body

What are important aspects for initiating an infection

• susceptible cells

• permissive cells

• sufficient number of virons

What are the 3 general routes of infection

• Mucosa

• eye

• skin

In viral spread where does primary replication take place

lymph nodes

in viral spread secondary replication and amplification generally takes place where in the body?

at target organ

How may stages of viremia take place during normal viral spread

2

what is the most common portal of entry for viruses

respiratory tract

The respiratory tract infections are commonly temperature dependent at lower temps animals will commonly get ____________ infections and at higher temps animals will get _____________ infections

• Upper respiratory tract

• lower respiratory tract

What are the defense mechanisms for the respiratory tract against viruses

• ciliated cells

• goblet cells

• mucus secreting glands

What antibody is a common immune response for upper respiratory tract infections

IgA

What antibody is an immune response to Lower respiratory tract infections

IgG

What are the consequences of a respiratory tract infection

• destruction of epithelial cells

• loss of ciliary activity

• loss of mucus lining

• inflammation with fluid exudation

• susceptibility to secondary infections

What is the common route of transmission for respiratory infections

• Direct transmission

• indirect (forties)

What are common routes through which animals obtain a gastro intestinal infection

• oral

• hematogenic spread

when comparing the oral route vs the hematogenic route which from has the shorter incubation time for gastro intestinal infections?

oral route

Viruses that cause gastrointestinal intestinal infection through the oral route have what characteristics

• acid/bile resistant

• protected by buffer

What is the most common type of virus that tends to cause gastrointestinal intestinal infection intestinal infections

non enveloped virus

What are consequences for gastro intestinal infection

• diarrhea

which route of infection is typically impermeable

skin

what are ways the virus is able to shed from the skin

• contact with small abrasions

• skin lesions

• feather follicles

what are consequences of transplacental infection

• fetal death/abortion

what determines the likelihood of fetal death and abolition

• viral virulence

• gestational age

in wha species are aboritons more common due to transplacental infections

those in which pregnancy is sustained by fetal progesterone

what are consequences of a CNS infection

• lytic infection of neurons

• non inflammatory infections

• progressive demyelination

What route do CNS infections occur through

• neuroses

• infected leukocytes

what aspect of the CNS system makes mounting an immune response difficult

• immunologically privileged site

• No MHC1 expression on neurons

What are some morphological aspects of the rabies virus

• enveloped

• RNA genome

the rabies virus replicates ________ in _________

• locally

• muscle

what are the 3 phases of rabies infection

1. prodromal phase

2. acute excitative phase

3. paralytic stage

one way to treat rabies is _____________

post exposure vaccinations and antibodies

An infection is established in an organism if ....

the organism is infected with a sufficient dose of viruses, and has permissive and susceptible cells.