What are the three types / categories of viral infections?
Acute, Latent, and Slow
What are the steps in an acute viral infection?
Infection -> incubation -> expression of symptoms -> recovery -> no more problem
Give an example of an acute viral infection.
What are the steps in a latent viral infection?
Infection -> incubation -> expression of symptoms -> probable recovery ->virus remains in body forever and may reactivate later.
Give an example of a latent viral infection.
What are the steps in a slow viral infection?
Infection -> very long incubation -> expression of symptoms -> death
Give an example of a slow viral infection
Prion diseases (vCJD, BSE, etc.)
Herpes Simplex 1 belongs to which viral family?
Herpes Simplex 1 causes what symptoms?
Cold sores and fever blisters
Herpes Simplex 1 is reactivated via sunburns or high fevers.
Herpes Simplex 1 is the STD form of herpes (genital herpes).
Simplex 2 is the STD form
Herpes Simplex 2 causes what symptoms?
Burning or tingling at SOI
Fluid-filled blisters at SOI
Herpes Simplex 2 can present as an oral infection.
True, although a genital infection is more common
Herpes Simplex 2 can reactivate via sunburn or other skin stresses (such as lacerations or stretch marks).
Reactivation is via physical or emotional stress
Herpes Simplex 2 has a 1 week incubation time.
Herpes Simplex 2 belongs to which viral family?
Varicella-Zoster belongs to which viral family?
What two diseases are caused by Varicella-Zoster?
Chicken Pox and Shingles
Chicken Pox is acquired through direct contact (skin to skin) with an infected person
Chicken Pox is acquired via the repiratory system
Chicken Pox has a one week incubation time
The incubation time is 2 weeks
Where does the Chicken Pox virus "set up shop?"
Nerve cells in the skin
What sympton does Chicken Pox present?
What causes a reactivation of Varicella-Zoster?
What do we call Varicella-Zoster when it does reactivate?
What is a possible complication of Varicella-Zoster?
How do you know Reyes' syndrome is happening?
Patient appears to improve then suddenly takes a drastic downturn presenting vomiting, brain dysfunction, and possibly coma or death
Reyes' syndrome has been linked to giving acetominophen to adults with shingles.
Although not well understood, Reyes' syndrome has been linked to giving aspirin to children with Chicken Pox.
What symptoms does shingles present?
Bumpy or scaly skin rash that tends to follow nerve bundles
What do we use to treat shingles?
We use acyclovir to treat shingles because it is the most effective cure
There is no cure. Acyclovir is merely a treatment to diminish the symptoms of shingles
Epstein-Barr virus (EBV) belongs to which viral family?
Epstein-Barr virus (EBV) causes what disease?
Infectious mononucleosis (a.k.a.: Mono)
EBV is transmitted via saliva (ex: kissing)
What is the hallmark symptom of EBV infection?
Person feels utterly drained of energy
How do we treat EBV infection?
Bed rest is the only treatment available currently and can last for a week or two to several months
Hepatomegaly is a possible issue with EBV infection
The possible issue is splenomegaly, not hepatomegaly
Burkitt's lymphoma is a possible complication of EBV infection, but it is almost exclusively seen in Africa.
Papilloma virus belongs to which viral family?
Papoviridae is a family of single-stranded linear RNA viruses
Papoviridae is a family of double-stranded circular DNA viruses
Papilloma virus causes _____ in humans and a few strains have been implicated in _____.
Warts, cervical cancer
Polyoma virus belongs to what viral family?
Polyoma and _____ cause a variety of cancers in _____.
Simian viruses, animals
Adenovirus belongs to the _____ family and is a _____-stranded _____ virus.
Adenoviridae, double, DNA
Adenovirus causes what?
Severe respiratory infections
What physical feature does adenovirus have to help it adhere to host cells?
Smallpox and Cowpox both belong to which viral family?
Poxviridae is a family of _____-stranded linear _____ viruses
Smallpox and Cowpox are so closely related that if you acquire immunity to one of them, you will also be immune to the other.
This is the basis for the smallpox vaccination, and the origin of the word 'vaccination', as cowpox scrapings were inoculated into people to give them immunity to smallpox ("vaca" is Italian for 'cow')
Why does vaccination work so well for smallpox/cowpox but not for other DNA viruses?
Poxviridae viruses are very stable, genetically speaking, meaning they have a very slow mutation rate so a vaccine will be effective for a long time
Picornaviridae is a family of _____-stranded linear _____ viruses
Polio virus belongs to which viral family?
Polio virus is a single-stranded circular DNA virus
It belongs to the picornaviridae family, so it is a single-stranded linear RNA virus
Polio is still a great viral threat for children in the developed world.
It has been almost eradicated in developed countries
The rhinoviruses belong to which viral family?
The rhinoviruses are single-stranded linear RNA viruses.
True, that's why they belong to Picornaviridae
What do the rhinoviruses cause?
What are the 3 reasons the common cold is so 'common?'
1. Diversity of the rhinovirus strains
2. Lack of drugs to cure rhinovirus
3. Lack of durable immunity (immunity to a strain will shortly wear off)
The flu vaccinations have to be renewed every year because they are not effective
There is a new flu vaccine every year because there is a new strain of the flu every year
Paramyxoviruses are a family of _____-stranded linear _____viruses
_____ is a large group of paramyxoviruses that cause the flu
Rubeola is also known by what name?
Rubeola belongs to which viral family?
It is actually quite difficult to transmit rubeola.
Measles are highly contagious
Rubeola is transmitted via respiratory secretions.
In what year was the first rubeola vaccine introduced and what was the result of that introduction?
1963, and the incidence of measles fell drastically in the U.S. until the mid 1980's
Why did measles make a come-back in the 1980's in the U.S.?
1. Lack of durable immunity
2. Vaccine was only about 95% effective
3. Many were never vaccinated
What is the incubation time for rubeola?
What are the symptoms of rubeola infection?
Patient will present with cold-like symptoms (sore throat, headache, cough), rash is possible which may also be in the oral cavity
What are Koplik Spots and what do they signify?
Koplik spots are the oral rash indicating rubeola infection
One in 2000 people infected with rubeola will develop this complication.
What viral family does mumps belong to?
Mumps virus is a _____-stranded _____ _____ virus.
single, linear, RNA
Mumps infects what part of the body?
What symptoms does mumps present?
Painful, swollen salivary glands usually accompanied by fever and painful swallowing
Why should adult males be particularly concerned about mumps?
4-7 days after the onset of symptoms, the virus can cause the testicles to become inflamed and lead to sterility
Mumps has a 2 week incubation time.
The incubation time is 16-18 days
Rubella belongs to which viral family?
Rubella is also known by what common name?
Rubella is stronger and more aggressive than rubeola.
Rubella is the milder form of measles
Like rubeola, rubella is transmitted via respiratory secretions.
Rubella has a 2-3 week incubation time
What symptoms does rubella present?
Patient may be asymptomatic, or they may present with a mild rash and a slight fever
What complications can occur with rubella infection?
- Congenital Rubella Syndrome in fetus (sort of like congenital toxoplasmosis)
- Loss of hearing
- Heart defects
- Mental retardation
The complications possible from rubella infection are very rare.
Rhabdoviridae is a _____-stranded _____ virus family
Rabies virus belongs to which viral family?
Rabies can only infect humans, dogs, and some wild animal species.
Rabies can infect any mammal species
Describe the morphology of the rabies virus.
Bullet shaped with an envelope and spikes
Why is rabies not very common in the U.S.?
People are pretty dilligent about vaccinating pets
Many programs to vaccinate wild animal populations, usually via oral methods
Post-Exposure Treatment (PET) protocol
What is PET?
Post-Exposure Treatment is a series of IM injections after being exposed to rabies that will prevent the disease
Rabies is transmitted via saliva.
How long is the incubation period for rabies?
30 - 50 days, but can be up to 6 years
What does the length of incubation time for rabies depend upon?
How nerve-rich the bitten area is (shorter incubations come from bites in nerve-dense areas while longer times come from bites in nerve-poor areas)
Rabies travels to the brain from the SOI via the bloodstream.
The virus follows the peripheral nerves to the CNS
What complication does rabies cause?
What characterizes an animal infected with rabies?
Alternating periods of agitation and calmness, violent throat spasms (this is the source of the 'foaming mouth') triggered by water (even just the sight of it)
Name and describe the two forms of rabies.
Furious rabies- animal is highly aggressive
Paralytic rabies- animal is minimally exciteable
Rabies eventually causes death due to damage to the nerves and brain tissues.
Retroviridae is a family of _____-stranded _____ viruses.
What viral family do the RNA tumor viruses belong to?
What do the RNA tumor viruses cause?
Leukemias and cancers in animals
HIV belongs to which viral family?
All forms of hepatitis have the same symptoms.
Symptoms of hepatitis
Infectious hepatitis is the common name for which strain of hepatitis?
Hep A is a _____-stranded _____ virus.
HAV has no envelope.
What are the transmission vectors for HAV?
Fecal-oral route and contaminated mollusks
HAV localizes where?
Epithelial cells of the GI tract
A systemic infection of HAV occurs when the virus enters the bloodstream, and this is referred to as "viriosis."
A systemic HAV infection occurs when the virus begins multiplying in the epithelial cells of the GI tract, and this is called "viremia."
Where is the highest HAV viral load found?
Where else besides the feces can HAV viral load be found (to a lesser degree)?
Saliva, blood, and urine
HAV can survive outside a host for only a few hours.
It can survive for several days
HAV is partially resistant to disinfectants.
What is the incubation time for HAV?
Who is most likely to express HAV symptoms and for how long?
Adults for about 2-21 days
What is the treatment for HAV infection?
There is none; you have to just let it run its course.
There is a vaccine for HAV, but it does not last long.
The vaccine does give long-term immunity
In 2/3 of HAV patients, this symptom is seen.
Hep B is known by what common name?
HBV is a _____-stranded _____ virus.
HBV has no envelope.
HBV is an enveloped virus
Where does the envelope around a virus come from?
It is part of the host cell's membrane.
HBV is transmitted via contaminated body fluids and this is called the 'parenteral' route.
True, this is why it is called serum hepatitis and poses such a risk to healthcare workers
What is the incubation time for HBV?
4-26 weeks (but it is mostly close to 4 weeks)
Jaundice is slightly less common in HBV than HAV.
It is more common
HBV has a 90% recovery rate.
HBV is dangerous because it poses risks to the liver, but not deadly since there is no mortality rate for it.
While HBV does pose risks to the liver, it also carries a 1% short-term mortality.
After recovery, about 30% of HBV hosts will become lifetime carriers of the virus.
10% will become permanent carriers
There is great concern about HBV because there is no cure and no vaccine for it.
There is no cure, however there IS a vaccine
HCV is a _____-stranded _____ virus.
HCV has an envelope.
How is HCV transmitted?
What is the incubation time for HCV?
There is no vaccine and no cure for HCV.
HCV carries great risk of liver damage.
HDV is a _____-stranded _____ virus.
HDV is an enveloped virus.
If you have been infected with HDV, you must have also been infected with HBV at some point.
True, you cannot get HDV without HBV being there
What is the incubation period for HDV?
If you have HDV, you are all but assured to have severe liver damage.
There is no cure and no vaccine for HDV.
True, however, since you MUST be infected with HBV to get HDV, getting the vaccine for HBV will cover you
What is the short-term mortality rate for HDV?
HEV is a _____-stranded _____ virus.
HEV has no envelope.
How is HEV transmitted?
What is the incubation time for HEV?
HEV carries a higher short-term mortality rate for pregnant women, but no one knows why.
HEV carries high risk for severe liver damage.
Chronic liver damage is not common in HEV
There is no cure for HEV, but there is a vaccine.