Virology 2 Flashcards
(28 cards)
How can influenza virus be spread?
Respiratory or salivary spread
How poliovirus be spread?
Faecal-oral spread
How can papillomavirus be spread?
Venereal spread
How can dengue virus?
Vector, biting arhtropod
How can rabies be spread?
Vertebrate reservoir
How can yellow fever virus be spread?
Vector-vertebrate reservoir
How do most viruses spread?
Enter via the epithelial cells of the mucosa because the epidermis of the skin is covered by dying cells producing keratin and provides a hostile environment for viruses
What are 6 ways in which viruses can enter?
Conjuctiva, Resp tract, Alimentary tract, Urogenital tract, Parenteral Inoculation, skin
What are the protective mechanisms for the resp tract?
Mucus, Cilia, Alveolar, Macrophages
How do viruses enter via resp tract?
Attach to specific receptors on epithelial cells
Name some localised resp tract viruses and some viruses that spread further?
Rhino and influenza are lcoalised.
Measles, Mumps, Rubella and varicella spread.
Mumps virus
1) Primary replication where?
2) Receptor is what?
3) What type of infection and what organs/system does it use?
4) what gland does it involve
1) Epithelial cells of URT(Upper resp tract)
2) Sialic acid
3) Systemic infection involving virtually all organs inc CNS
4) Salivary gland
Describe the 3 ways in which an ingested virus can move via alimentary tract
1) Replicate in the mouth but not further down the tract - herpes simple
2) Infect the oropharynx and be swallowed causing enteritis - rotavirus
3) Alimentary tract into circulation - enteroviruses
What other way can the alimentary tract become infected
Via the rectal route - HIV
Viruses that are swallowed and infect the intestinal tract are normally resistant to what so?
Resistant to acid and bile and do not have an envelope
2 main ways in which alimentary tract viruses are spread?
Mouth or Oropharynx
Fecal - Oral spread
Look at pathogensis of acute poliomyelitis
okay
3 mechanisms of spread in the body
Local spreading on epithelial surfaces
Subepithelial invasion and lymphatic spread
Spread via bloodstream - Viremia
2 types of infections
Disseminated - spread beyond primary site
Systemic - many organs infected
What are the ways to determine local or systemic infections? what are required?
Availability of receptors for the virus and of cleavage activating proteases.
Optimal temperature for replication.
Ability to withstand harsh conditions.
Polarised release (apical versus basolateral)
Ability to replicate in macrophages and lymphocytes
Viruses may be free or what in where?
May be free in plasma - HBV
May be cell associated - Measles in monocytes, HIV in T cells
May be free in the blood
Viruses in the blood are vulnerable to circulating to where and what is evolved?
Vulnerable to circulating macrophages and later antibodies. They have evolved to have an amplification stage to increase likelihood of surviving to reach the point of exit.
what is primary viremia? and secondary viremia?
Primary is where the virus is detected before amplification .
Secondary is once the virus has risen
What are the 4 outcomes of viral infection?
Fatal - viral diseases where man is not the natural host so have high mortality rates, Ebola
Full recovery - Virus completely cleared by hosts immune system eg influenza
Recovery but permanent damage - Virus cleared but left with symptoms Eg poliomyelitis, cancer
Persistent infection - virus not cleared and can resurface to cause disease
