Viro Summary Flashcards
Smallest infectious agents and contain only one type of nucleic acid
Viruses
Viruses are classified into groups, designated virus families, based on common properties,
▪︎virion morphology,
▪︎genome structure,
▪︎virus protein properties, and
▪︎strategies of replication.
Obligate intracellular parasites and multiply
only in living cells.
Viruses
Encodes virusspecific products, and the host cell provides energy, biochemical
precursors, and biosynthetic machinery.
viral nucleic acid
Attachment to a cell via binding to specific receptors on the cell surface, entry into the cell, uncoating of the viral genome, regulated expression of viral transcripts, synthesis of viral proteins, replication of viral genomic nucleic acid, assembly of new progeny viruses, and release of new virions from the cell.
Steps in viral replication
Some viruses are _________ based on ease of host-to-host transmission and mortality rates.
potential bioterrorism agents
A process when a virus infects a host.
Viral pathogenesis
Most viruses enter their hosts ________
through the respiratory or gastrointestinal tract.
Most viral infections are _____ and do not result in clinical disease.
inapparent
Most viral infections are _______ and are cleared by the host, but some lead to chronic (persistent) long-term infections.
self-limiting
Cytokines that are central to the antiviral innate immune response of the host.
Interferons
______ determine the outcome of viral infections
viral and host factors
Some viruses cause ___________ at the primary site of entry; other viruses spread and produce disease at distant sites in the body
localized infections
Most effective method for preventing viral infections.
Viral vaccines
Both ______ and _______ vaccines are available
▪︎killed-virus
▪︎live-virus
Parvoviruses are small viruses with
single-stranded DNA genomes.
Human B19 virus targets
erythroid progenitor cells.
B19 is associated with
erythema infectiosum (fifth disease), transient aplastic crisis, pure red cell aplasia, and hydrops fetalis
Associated with acute respiratory disease and gastroenteritis in children, but causation has not been proven
Human bocaviruses
Nonenveloped, icosahedral viruses with a DNA genome.
Adenoviruses
Adenoviruses are excellent models for molecular studies of ________
eukaryotic cell processes
Establish long-term latent infections in tonsils and adenoids.
Group C viruses
Group C viruses cause respiratory infections in children ______ and in military recruits _______.
▪︎types 1–7
▪︎types 3, 4, 7
______ severe eye infections (epidemic keratoconjunctivitis).
Types 8, 19, and 37
_______ causes gastroenteritis in young children.
▪︎Enteric adenoviruses,
▪︎types 40 and 41
Adenoviruses can cause severe disseminated disease in _______ and _________.
▪︎immunocompromised and
▪︎transplant patients.
There are no specific treatments for ___________.
adenovirus infections.
________ are large viruses with a double-stranded DNA genome
Herpesviruses
All herpesviruses establish
lifelong latent infections
Herpesviruses may cause severe disease in __________.
immunocompromised persons
__________ share some sequence homology, exhibit a broad host range, grow rapidly, and establish latent infections in nerve cells
Herpes simplex virus types 1 and 2
_________ is classically associated with oropharyngeal lesions, and ______ with genital infections.
▪︎Herpes simplex virus type 1
▪︎type 2
__________ is the most common cause of sporadic, fatal encephalitis
Herpes simplex virus type 1
_________ causes chickenpox on primary infection in children and _______ after reactivation in adults.
▪︎Varicella-zoster virus
▪︎zoster (shingles)
A ____________ is available. A stronger version of the vaccine is licensed to prevent shingles in older individuals.
Live, attenuated varicella vaccine
____________ are important causes of developmental defects and mental retardation after congenital infections
Cytomegaloviruses
Inapparent infections with cytomegalovirus are common during _________.
childhood
__________ are at risk for reactivated cytomegalovirus disease, especially pneumonia.
Organ transplant recipients
Establishes latent infections in B lymphocytes.
Epstein-Barr virus
Epstein-Barr virus causes ________ and is associated with several human cancers, including __________ and ____________.
▪︎infectious mononucleosis
▪︎Burkitt lymphoma
▪︎nasopharyngeal carcinoma
___________ is the cause of Kaposi sarcoma, a vascular tumor.
Kaposi sarcoma herpesvirus
Large and complex viruses that contain many enzymes, including a transcriptional system.
Poxviruses
Family Poxviridae includes _______, the agent of smallpox, the first viral disease eradicated from the earth.
variola virus
Poxviruses encode _______ that inhibit the host immune defense system.
proteins
Used for smallpox vaccination and as a laboratory model for poxviruses.
Vaccinia virus
There is a _____________ in association with immunodeficiency, immunosuppression, malignancies, and pregnancy
risk with smallpox vaccination
Most poxvirus infections are accompanied by a _________.
vesicular rash
A potential biothreat agent because the human population today has little or no immunity
Smallpox virus
Patients with symptoms suggestive of pox viruses need to be _________ until smallpox is excluded diagnostically.
isolated with supportive treatment
Causes benign epidermal tumors.
Molluscum contagiosum
____ and _____ are transmitted by fecal–oral exposures
▪︎HAV and
▪︎HEV
_____, _____, and ______ are transmitted by parenteral routes.
▪︎HBV,
▪︎HCV, and
▪︎HDV
Causes outbreaks of disease, often in camps or institutions
HAV
Whereas ____, _____, and ______ frequently establish chronic infections, ____ and ___ do not.
▪︎HBV, HCV, and HDV
▪︎HAV and HEV
Most individuals ____________ as infants develop chronic infections and are at risk for liver disease as adults.
infected with HBV
The ____________ lead to chronic infections even in adults; those individuals are at risk of later development of liver disease.
majority of HCV infections
____________ is the most frequent cause for adult liver transplantation
Liver disease associated with HCV
______________ carriers may lead to highly fatal fulminant hepatitis
HDV superinfections of HBV
___ and ___ are both causes of liver cancer that may arise many years after infection.
▪︎HBV and
▪︎HCV
__________ are available against HAV and HBV.
Virus vaccines
__________ are small, nonenveloped, single-stranded RNA-containing viruses that replicate in the ________.
▪︎Picornaviruses
▪︎cytoplasm
Diseases caused by these viruses include ___________________.
▪︎paralysis, ▪︎aseptic meningitis, ▪︎pleurodynia, ▪︎myocarditis, ▪︎hepatitis, ▪︎skin lesions, ▪︎respiratory illnesses, ▪︎diarrhea, ▪︎fevers, ▪︎common colds, ▪︎conjunctivitis, and ▪︎severe disease of infants.
Cause the common cold.
Rhinoviruses
___________ is the usual means of enterovirus spread; sources can involve water, food, hands, and utensils.
Fecal contamination
Transmitted by virus-contaminated respiratory secretions, with hand contamination an important mode of spread
Rhinoviruses
Subclinical infection with __________ is far more common than clinical disease.
enteroviruses
A serious and highly contagious disease of animals, is caused by an unrelated picornavirus classified in the Aphthovirus genus.
Foot-and-mouth disease
