Page 265 - Review of Medical Microbiology and Immunology ( PDFDrive )

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PART III Basic Virology
254
changes. This observation highlights the wide variations in
The stages of a typical viral infection are the same as
the nature of the interaction between the virus and the cell,
namely, an incubation period during which the patient is
ranging from rapid destruction of the cell to a symbiotic
relationship in which the cell survives and multiplies
asymptomatic, a prodromal period during which nonspe-
despite the replication of the virus.
cific symptoms occur, a specific-illness period during
recovery period during which the illness wanes and the
THE INFECTED PATIENT
patient regains good health. In some patients, the infection
persists and a chronic carrier state or a latent infection
Pathogenesis in the infected patient involves (1) transmis- which the characteristic symptoms and signs occur, and a
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occurs (see later).
mebooksfree.com mebooksfree.com mebooksfree.com Viruses are transmitted to the individual by many different mebooksfree.com
sion of the virus and its entry into the host; (2) replication
of the virus and damage to cells; (3) spread of the virus to
Transmission & Portal of Entry
other cells and organs; (4) the immune response, both as a
host defense and as a contributing cause of certain diseases;
and (5) persistence of the virus in some instances.
routes, and their portals of entry are varied (Table 32–1).
TABLE 32–1 Main Portal of Entry of Important Viral Pathogens
Virus
Portal of Entry
Disease

Rhinovirus
Common cold

Bronchiolitis
Respiratory syncytial virus
Epstein–Barr virus
Respiratory tract 1 Influenza virus Influenza
Infectious mononucleosis
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Varicella-zoster virus
Chickenpox
Herpes simplex virus type 1
Herpes labialis

Mononucleosis syndrome

Cytomegalovirus

Measles virus
Measles
Mumps virus

Mumps
Rubella virus
Rubella

Pneumonia
Hantavirus

Pneumonia
Adenovirus
Slapped cheeks syndrome
Parvovirus B19

Poliomyelitis
Poliovirus
Rotavirus

Diarrhea
Norovirus
Gastrointestinal tract 2 Hepatitis A virus 3 Hepatitis A
Diarrhea
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3
Rabies virus
Skin
Rabies
Yellow fever

Yellow fever virus
3
Dengue
Dengue virus

Human papillomavirus
Papillomas (warts)
Genital tract
Human papillomavirus
Papillomas (warts)
Hepatitis B
Hepatitis B virus

Human immunodeficiency virus
Acquired immunodeficiency syndrome (AIDS)

Herpes simplex virus type 2
Herpes genitalis and neonatal herpes

Blood
Hepatitis B virus
Hepatitis B
Hepatitis D virus
Hepatitis D
Human T-cell lymphotropic virus
Leukemia
Transplacental Hepatitis C virus Hepatitis C
Human immunodeficiency virus
AIDS
Mononucleosis syndrome or pneumonia
Cytomegalovirus
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Congenital abnormalities
Cytomegalovirus

Congenital abnormalities
Rubella

Hydrops fetalis
Parvovirus B19
1
Transmission of these viruses is typically by respiratory aerosols or saliva.
2
Transmission of these viruses is typically by the fecal–oral route in contaminated food or water.
3
Transmission of these viruses is typically by the bite of an infected animal.
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