Viruses Flashcards
Four types of RNA viruses
- Positive single-stranded RNA (can be used immediately to make a protein
- Retroviruses (+ssRNA that convert genome into DNA)
- Negative single-stranded RNA (has to be translated/ altered first)
- double stranded RNA
Rhinovirus diseases
Upper respiratory tract infection (common cold)
Rhinovirus transmission, prevention and treatment
Transmission: aerosols (>1m), fomites and person to person contact (hand to hand is most common).
Prevention: hand washing. Also tend to become immune to more serotypes as we age
Treatment: none. Pleconaril can reduce length/ severity if taken at right time. Can treat symptoms but not infection
Rhinovirus signs and symptoms
Sneezing, runny nose (rhinorrhea), congestion, sore throat, headache, malaise, cough
Lesions observed in all stages of poxvirus infection
Vesicle (like a burn blister with thicker skin)
Pustule: like a whitehead pimple
Two forms of small pox
Major (severe cases with 20% mortality)
Minor: much milder, though still shows blisters
Two forms of pox viruses
Small pox
Mulluscum Contaginosum
Small pox forms of transmission
Contagious: spreads person to person through contact and saliva droplets (even on breath) incubation for 7-17 days
Smallpox prevention
Vaccines, even if given after exposure (within the 4-day window), largely eradicated in the industrialized world
what is Molluscum contagiosum and how is it treated
- Caused by molluscopox virus
- causes smooth, waxy papules, and will resolve on its own in healthy individuals
- immunocompromised people may need to have the lesions surgically removed
Types of Herpes viridae (most common DNA virus)
HHV-1: causes herpes/ hand and mouth
HHV-2: causes genital herpes
HHV-3: Varicelles Zoster: chicken pox and shingles
HHV-4: Epstein Barr Virus
HHV-5: Cytomegalovirus
HHV-6: Roseolovirus (linked to M.S.)
HHV-8: Karposi’s Sarcoma in AIDS patients
Herpes (HHV-1 and HHV-2) description and treatment
Description: causes painful blisters/ sores on mouth, hands, or genitals (mostly HHV2).
Treatment: Reduce pain/ spread through contact. Not much treatment, just prevention
Varicella Zoster/ Chicken pox (HHV-3)
Chicken pox: just irritating in children (self-limiting itchy rash) but more dangerous in adults
Shingles: latent disease- painful blistering patches along the tract of a nerve.
Vaccines for both, but otherwise manage symptoms/ pain
Epstein-Barr Virus (HHV4)
Weak immune: tongue issues/ lymphoma
Healthy: asymptomatic
Strong: over-reacts and get mononucleosis symptoms (fatigue)
Weak: chronic fatigue syndrome
Cytomegalovirus (HHV-5) description and treatment
Cells become enlarged- no damage in most healthy patients. Cells show “owl eyes”
Treatment: Virsen used to treat infections of the eye
Roseolovirus (HHV-6)
May be linked to multiple sclerosis, symptoms similar to mono, and may make patients more susceptible to AIDS
HHV-8
Causes karposi’s sarcoma (cancer), especially in those with AIDS
Papilloma virus disease and treatment/ prevention
Causes warts, with genital warts being associated with increased cervical cancer risk.
Can remove warts w/ over the counter, or surgically, and can prevent some serotypes with vaccines (HPV vaccine)
Polyloma virus diseases, treatment and prevention
BK (urinary tract) and JC (WBC) viruses cause tumors in humans and animals,
JC can cause leukoencephalopathy, which destroys white matter in the brain (paralysis and death)
Viruses that cause “colds”
- Rhinovirus
- Adenovirus
Diseases caused by adenovirus
Common cold, GI distress, viral pinkeye
See hepatitis table
Do the hepatitis table!
Three types of enteroviruses
- Poliovirus
- Coxsackievirus
- Echovirus
Four conditions caused by polio viruses and their differences`
- Asymptomatic: typical in immunocompetent people
- Minor polio: GI or respiratory infection that doesn’t include CNS
- Nonparalytic polio: leads to aseptic meningitis (no virus in spinal fl)
- Paralytic polio: may be spinal, bulbar (medulla) or both
Polio virus transmission, treatment, and prevention
Transmission: fecal-oral (from pharynx to bloodstream)
Treatment: none, mostly relief of symptoms
Prevention: inactivated polio vaccine (injection, no risk of disease)
Oral polio vaccine- can cause disease in susceptible host
“Cruise-ship virus”
Calicivirus: can cause diarrhea, nausea and vomiting. Norowalk viruses causes most cases of viral gastroenteritis
No treatment, and prevention= good civil water hygine, surface disinfection, and frequent hand-washing
Difference between calicivirus and astroviruses
Calicivirus causes diarrhea, nausea AND vomiting
Astrovirus can cause diarrhea but no vomiting
Transmission method of arboviruses
Zoonotic vectors (mosquitos, ticks, to and from animal hosts)
Three examples of arboviruses and their diseases
Togavirus: Eastern (worst in humans), western, and Venezuelan equine encephalitis
Flaviviridae: Dengue fever (pain, hemorrhaging, hepatitis) and yellow fever (hepatitis, hemorrhaging, fever, shock).
Cause of German measles (and prevention)
Rubella virus,
Yes, is part of the MMR vaccine
Symptoms of rubella
Begins in respiratory system but spreads through body, and can cause arthritis and encephalitis in adults, and congenital defects in babies in uterus
The 5 childhood diseases that are caused by viruses
- Rubella (German measles)
- Chicken pox (varicella Zoster)
- Measles (rubeola)
- Fifth disease
- Rosella
What are Oncogenic retroviruses and what diseases do they cause?
- Human T-Lymphotrophic virus (HTLV) 1. Acute T-cell lymphocytic leukemia
- HTLV 2: causes rare cancer called hairy-cell leukemia
Transmission of HTLV (oncogenic retroviruses)
Through sexual intercourse, blood transfusion and contaminated needles
immunosuppressive retroviruses (lentiviruses)
it’s Human Immunodeficiency Virus (HIV) and it can lead to AIDS
Two types of HIV:
HIV-1: prevalent in US and Europe
HIV-2: prevalent in Africa
HIV diagnosis, treatment and prevention
- Diagnose based on symptoms, low CD4 lymphocyte counts, and presence of antibodies against HIV (definitive PCR test)
- Antiretroviral therapy available for treatment (drug cocktail)
- Prevention: safe-sex/ abstinence, clean needles, blood donation screening
Measles transmission and disease state
transited in air via respiratory droplets (<1m), spreads in large/dense populations of people very quickly
Disease: koplik spots appear in mucous membranes of mouth, then lesions over head and body
Rarely, can result in pneumonia, encephalitis, and subacute sclerosing pan-encephalitis (SSPE)
Measles diagnosis, treatment, and prevention
Sings of measles spots in mouth usually diagnostic
Treatment: can only prevent disease with immunoglobulin right after exposure, but before symptoms begin
Prevention: vaccine administered in infancy and again before grade school (frequent cause of death in other unvaccinated countries)
Parainfluenza virus transmission and disease
strains 1-3 associated with lower respiratory infection
Strain 4= mild upper respiratory condition
CROUP: severe condition in children, inflammation of airways, coughing, most recover within a few days but can require intubation if severe
Mumps disease, treatment, prevention
Spread through respiratory secretions
Painful enlargement of the parotid salivary glands
Meningitis, pancreatitis, or deafness in one ear may occur (or no symp)
No treatment, but vaccine has mostly eradicated the condition
Respiratory Syncytial Virus (RSV) disease and prevention
Lower respiratory tract infection: difficulty breathing can be cause of death in small children. Immune response can damage the lungs (it is prevalent in the US)
No treatment or vaccine, but nursery hygiene can prevent spread
Causative agent of rabies
The virus itself
Rabies disease/ diagnosis
Treatment
And prevention
-Zoonotic disease, causing hydrophobia, seizures, paralysis and hallucination. Causes spinal cord and brain degeneration
-Diagnosis usually w/ symptoms, but at that point too late to intervene
Postmortem can be confirmed by negri bodies in the brain
Treatment with human rabies immune globulin (or vaccine) injection at site of infection right after bite
- prevention through both human and pet vaccination
Two causative agents of hemorrhagic fevers (and their spread)
- Ebola and Marburg viruses are the causative agents
- Spread person to person through body contact (even sweat/ sebum)
- Fruit bats are natural reservoirs
Diseases of paramyoxoviridae family
Morbillivirus (measles)
Respirovirus (parainfluenzae)
Rubulavirus (mumps virus)
Pneumovirus (RSV)
Example of orthomyoxoviridae family
Influenza virus (types A and B)
Two proteins in influenza virus vital for attaching to host cells:
Glycoproteins
- Nuraminidase (NA): hydrolyzing mucus of lungs to get access to cell surface
- Hemagglutinin (HA): attaches to pulmonary epithelial cells and triggers endocytosis
Antigenic DRIFT
- Influenza enters host cell
- Mutations in antigen genes occur during viral replication within host cell’s nucleus
- New strain of influenza virus, differing slightly from original virus, exits the cell
* * can occur in A or B
Antigenic SHIFT
- Two different strains of infA enter same host cell
- Genes and antigens from both viral types are incorporated into new virions
- New influenza virus, which can be VERY different from the original two viruses, exists the cell
Influenza treatment and prevention
Treatment: oseltamivir or zanamivir inhibit neuraminidase
Prevention: Immunization with multi-valent vaccines (only against strains included in vaccine)
Bunyaviruses diseases (no treatments) and prevention
Causes variety of diseases (usually mild): Arboviruses= Rift Valley fever, California encephalitis, hemorrhagic fever
Hantavirus: American strains can cause hantavirus pulmonary syndrome (severe and often fatal pneumonia)
- Prevention: limiting contact with animal vectors/ Arthropoda
- Vaccine against Rift Valley fever
Arenaviridae diseases
lassavirus (hemorrhagic fever)
deltavirus (hepatitis D)
Rota virus infection
Most common cause of infantile gastroenteritis, common cause of death in developing countries
- fecal-oral transmission
- infection usually self-limiting, replace water and electrolytes
- prevent with good hygiene and proper sewage treatment
Vaccine can give ~some~ protection
