Flashcards in Common Viral Diseases Deck (116):
What part of viruses are the complete infective particle and do not grow?
WHat are small circular RNA molecules with a rod like secondary structure that possess no capsid or envelope?
A virus particle, also known as a virion, is made of what?
nucleic acid (DNA or RNA) enclosed in a protein shell or coat.
How big are viruses?
15 - 25 nanometers in diameter
The type of genetic material found in a particular virus depends on the nature and function of the specific virus.
For example, double-stranded DNA viruses typically must enter the host cell's what before it can replicate?
Where does RNA viruses replicate?
host cell's cytoplasm
What is a capsomere?
Whats the funciton of a capsid?
protein units that compose the capsid of a virus
Function to protect the viral genetic material from damage.
In addition to the protein coat, some viruses have specialized structures. What is special about the flu virus?
The flu virus has a membrane-like envelope around it’s capsid.
The envelope has both host cell and viral components and assists the virus in infecting its host
The basic process of viral infection and virus replication occurs in 6 main steps. What are these steps?
1. Adsorption - virus binds to the host cell.
2. Penetration - virus injects its genome into host cell.
3. Viral Genome Replication - viral genome replicates using the host's cellular machinery.
4. Assembly - viral components and enzymes are produced and begin to assemble.
5. Maturation - viral components assemble and viruses fully develop.
6. Release - newly produced viruses are expelled from the host cell.
The key components of current classification systems are?
1. Type of symmetry of the virus capsid (helical versus icosahedral)
2. Presence or absence of a lipid envelope
3. Type and structure of the viral nucleic acid and the strategy used in its replication
Why does the HA and NA make the flu virus so virulent?
These protein subunits can swap back and forth and become resistant to the vaccine that has been made
Class I viruses are what kind of viruses?
What are the viruses in this class?
- double stranded DNA
What are 2 examples of papovaviruses?
Examples of adenoviruses?
Examples of the herpesvirus?4
Examples of the poxvirus?
1. warts, cervical cancer
2. respiratory diseases
3. (cold sores, genital herpes, chicken pox, mononucleosis)
4. (smallpox, cowpox)
Class II viruses are what kind of viruses?
What is the virus in this class?
single stranded DNA
-easy to recognize by the body because we dont have them
Class III virsuses are what kind of viruses?
What are the viruses in this class? 4
- double stranded RNA
Hepatitis C virus
WHat are examples of picornavirus? 2
What are exampes of a togavirus? 2
1. (polio, common cold)
2. (rubella, yellow fever)
Class IV viruses are what kind of viruses and what viruses are in this class?5
- positive single stranded RNA itself acting as mRNA
GIve an example of a rabdovirus?
Give an example of a paramyxovirus? 2
Give an example of an orthomyxovirus?
Give an example of a bunyavirus?
(Korean hemorrhagic fever)
WHat kind of virus is a class V virus.
What kind of virus is in this category and what does it cause?
- negative single stranded RNA used as a template for mRNA synthesis
What kind of viruses are class VI viruses and what virus is in this class?
GIve two examples?
What kind of viruses are class VII viruses and what virus is in this category?
- positive single stranded RNA with a DNA intermediate in replication
Retrovirus (leukemia, AIDS)
- double stranded DNA with an RNA intermediate in replication.
Hepatitis B virus
Viral exanthematous diseases?
1. Chickenpox/Herpes zoster
2. Infectious mononucleosis
3. Roseola infantum (Sixth Disease or Erythema subitum)
4. Fifth disease (Erythema infectiosum)
7. Enteroviral exanthems
Enteroviral exanthems examples? 2
DDx of exanthematous eruptions?
1. Rickettsial infections
2. Mycoplasma pneumoniae
3. Syphilis- palms and soles
4. Typhoid fever-
5. Bacterial toxins- staph - toxin shock syndrome
6. Drug eruptions
7. Live-virus vaccinations
What are the Human herpes viruses in order?
1. HHV-1: Herpes Simplex Virus 1 (HSV1)
2. HHV-2: Herpes Simplex Virus 2 (HSV2)
3. HHV-3: Varicella-Zoster Virus (VZV)
4. HHV-4: Epstein-Barr Virus (EBV)
5. HHV-5: Cytomegalovirus (CMV)
6. HHV-6: Exanthema (or Roseola) subitum (Roseola infantum or Sixth Disease)
7. HHV-7: T-lymphotropic virus (could cause cancer)
8. HHV-8: Virus associated with Kaposi’s sarcoma
What viruses have the blistering rash look?
HSV 1and 2 and chicken pox
How does herpes simplex infect infect the body?
1. through mucosal membranes or abraded skin
2. Latent infections harbored in neuronal cells
How is the rash described for HSV?
What are the clinical manifestations for the oral facial lesions for the primary infection of HSV? 2
What demographic is it commonly seen in?
What are the other symtpoms? 6
How long does it last?
What does it reoccur as?
Dew-drop on rose petal
Gingivostomatitis (canker sores on gum) and pharyngitis most frequent
Commonly seen in children and young adults
4. inability to eat,
5. irritability and
6. cervical adenopathy lasts 3-14 days
Herpes labialis (“Cold Sores”)
HSV urogential lesion systemic symtpoms? 4
What will the pt experience in the prodromal phase?
3. malaise and
Vesicular lesions of external genitalia with
3. dysuria (horrible pain peeing),
4. vagina and urethral discharge,
5. tender inguinal lymph adenopathy
patient will usually present early. makes area sore and tender first then you get the lesions
Moist ulcers will form in how many days with HSV?
How long will they last untreated?
What are recurrent infections of HSV caused by? 5
Vesicles form moist ulcers after several days and crust over in 1-2 weeks of left unaddressed
Are induced by stress, fever, infection, sunlight, chemo.
Complications of HSV?
1. Ocular disease- herpetic kerokitis
2. Neonatal and Congenital infections
3. Bells Palsy (facial nerve paralysis)
4. Encephalitis and recurrent Meningitis- you can treat it with your cyclovirs IV
If we see diseminated herpes what should we think about?
What is the most common cause of viral encepholopathy?
AIDS or some other kind of immunosuppression
How do we diagnose HSV?
Usually clinically made
1. viral culture (only if its blistering)
3. Direct flouroscence antibody
4. Tzanck prepartion
5. Types specific serologic tests
What have emerged as a more sensitive method to confirm HSV infection in clinical specimens obtained from genital ulcers, mucocutaneous sites, and cerebrospinal fluid?
What test is particularly useful for the detection of asymptomatic HSV shedding?
real-time HSV PCR assays
What test is used to detect HSV in clinical specimens?This test is specific and reproducible.
Direct fluorescent antibody
What test helps us identify the cytopathic effect of the virus (multinucleate giant cells) and can be performed on lesions scrapings?
Why dont we use it more?
What test is the only test that can determine whether an infection is HSV1 or 2?
low sensitivity and specificity and is only helpful if positive.
What are inclusion cells in HSV?
inclusion cells are the virus replicating in the cell
What is the management for Herpes simplex acute infections?
Antiviral agents only shorten duration of symptoms by 1-2 days
Cant do suppressive therapy too. Daily
Where does herpatic whitelow occur?
finger and nails
Two distinct clinical presentations for herpes zoster. What are they?
Primary infection: Chickenpox
Recurrent infections: Herpes zoster
Primary infection by Varicella Zoster is transmitted how?
VZV probably infects dorsal root ganglia during primary infection. Certain sitations will trigger it to come out
Incubation period of varicella zoster?
Infected persons are infectious for how long?
10-21 days (usually 14-17)
48 h before onset of vesicular rash, throughout vesicle formation (~4-5 d), and until all vesicles are crusted.
Primary infection: Chickenpox?
1. Rash, fever (100-103F) lasting 3-5 days, malaise
2. Skin lesions are hallmark of disease:
Maculopapules, vesicles, and scabs in varying stages of development (“crops” of lesions) on an erythematous base of 5-10 mm
3. Distribution centripetal
(much more common on trunk)
Clinical presentation for varicella zoster recurrent infection or shingles?2
What are the most common dermatomes? 2
1. Unilateral vesicular eruptions which develop within a single dermatome (T3 to L3 most common)
2. Often associated with severe pain
Diagnostics for varicella zoster?
Usually clinically made
Tests can include
1. Specialized complement fixation and virus neutralization in cell culture
2. Fluorescent antibody test of smear of lesions
1. Cell culture
2. Flourescent antibody stain
Management of varicella zoster:
Primary infeciton prevention?
Recurrent infection? 2
1. Primary infection prevention: Vaccination
2. Primary disease: Prevent secondary infections
3. Recurrent infection: Zoster
A. Antivirals (high dose)
HOw is EBV transmitted and what does it infect in the body?
Peak incidence occurrence?
How long can it be contagious/symtpomatic for?
B-cell lymphotropic virus primarily transmitted in saliva
4-8 weeks incubation period
Peak incidence occurrence
Ages 14-16 for girls
Ages 16-18 for boys
EBV shed from oropharynx for up to 18 months post-infection
Clinical presentation for EBV:
Subclinical or mild when infected during childhood
Infectious mononucleosis defined by transient appearance of heterophil Ab and clinical triad
3. Severe pharyngitis with exudates
How long is the fever for in EBV?
How long is the lymphadenpathy and what nodes is it?
How long does pharyngitis last?
1. Fever/chills: 7-14 days duration (may be prodromal)
2. Lymphadenopathy rarely exceed 3 weeks duration (Posterior chain)
3. Severe pharyngitis with exudates which is maximal for 5-7 days and resolved over following 7-10 days
Why are the lymph nodes enlarged in EBV?
The B cells are replicating in them
Other common signs/symptoms of primary infection?
What else is a risk factor in the furture if you've had EBV?
1, Headache, malaise, anorexia
2. Soft palatal petechiae
3. Maculopapular rash (especially with administration of amoxicillin/PCN)
4. Splenomegaly and mild hepatic tenderness in up to 50%
1. Nasopharyngeal carcinoma
2. B-cell lymphomas (Burkitt’s lymphoma)
Laboratory findings for EBV?
1. Throat culture ( to check for B-Hemolytic strep)
3. Heterophil antibodies
4. Atypical lymphocytosis in about 75%
5. EBV-specific immune response
When do we become positive for heterophil antibodies after we have been infected with EBV?
What are the specific antigens that are tested for EBV?
What do we need to make sure to do for mono on physical exam?
Become positive within 4 weeks after onset of symptoms
EBV antibody titers directed at several antigens
1. EB virus capsid antigen - (VCA)
2. Antibodies to EBV nuclear antigen – (EBNA)
Palpapate the spleen
Complications (many but infrequent)?
1. Bacterial Strep pharyngitis
3. Splenic rupture
Neurologic symtpoms for EBV?
Hematologic symtpoms are EBV? 2
1. CN palsies (Bell’s palsy)
2. Guillain-Barre syndrome
Epstein-Barr Virus management?
1. most cases requiring only supportive therapy
2. Acetaminophen or NSAIDS
3. Warm salt water gargles
4. Adequate rest (return to school/work based upon Sx)
5. Avoid contact sports for 6-8 weeks from onset
When will the fever in EBV disappear?
When will the EBV Lymphadenopathy and splenomegaly disappear?
How does CMV spread?
1. Prolonged close contacts (family, day-care centers, etc)
2. Blood/body fluids: transfusion (containing viable leukocytes), maternal-fetal transmission, STD
Congenital CMV occurs almost exclusively when?
almost exclusively when pregnant women acquires primary infection (vs. reactivation)
When does perinatal CMV occur?
when infant is infected at time of delivery through an infected birth canal or postnatal contact with maternal milk or other secretions
What are the biggest risks for developing CMV?
HIV, Pregnancy, Organ transplants
Clinical presentation for congenital CMV?
1. inapparent infection (most) to
2. severe/disseminated (~5%)
5. jaundice common (60-80%)
7. growth retardation,
8. prematurity (30-50%)
Perinatal CMV clinical presenation?
1. poor weight gain,
5. anemia and
6. atypical lymphocytosis
1. Heterophil Ab negative mononucleosis syndrome
2. Prolonged high fevers, profound fatigue and malaise
3. Myalgias, headache & splenomegaly are frequent
4. Exudative phayngitis and cervical adenopathy are rare
5. Occasional rubelliform rash
CMV laboratory tests?
What's the important test?
1. viral culture
3. Antigen assays
4. Tissue confirmation with AIDS related CMV
What part of the body can CMV be cultured from?
4. cervicovaginal secretions, 5. cerebrospinal fluid (CSF), 6. bronchoalveolar lavage fluid, and
Three things to look for in CMV?
1. SIGNIFICANT hepatomegaly or splenomegaly
3. blueberry muffin rash
Etiologic agent for Fifth's disease?
What is the route of transmission?
Human Parvovirus B19
Respiratory tract is probably route of transmission
fifth's disease (Erythema infectiosum)?
1. Mild febrile exanthematous disease with little or no prodrome
2. Low-grade fever,
3. varying degrees of conjunctivitis,
4. upper respiratory complaints,
5. cough, myalgia, itching,
6. nausea and diarrhea
7. Slapped face lesions (fiery cheeks)
8. Circumoral pallor
9. Bilateral symmetric eruptions (maculopapular slightly raised blotchy areas with reticular or lacy pattern)
10. Rash that lasts about a week
are initial signs and symptoms
What does the rash look like in Fifth's disease?
How would we treat it?
reticular- not raised
treat with NSAIDS and tylenol
How is the diagnosis for 5th disease made?2
Usually made clinically in kids
1. Elevated titer of IgM anti-parvovirus antibodies
2. PCR in serum
Roseola (infantum)-Sixth Disease is a benign disease in children of what ages?
What cell do they target?
What is Roseola the major cause of?
In older children/adults, associated with several illnesses. What are they?
infants 6 months months to 4 y/o (most commonly seen in children
HHV6 – b-cell lymphotropic virus
Major cause of infantile febrile seizures!!
In older children/adults, associated with several illnesses: hepatitis, Immunocompromised states, chronic fatigue syndrome, others
What will the progression of the disease look like?
1. high high fever (up to 105) and causes child to sieze.
2. have to do workup for menigitis and encephalopathy
3. Rash and low grade fever- this will happen after the high fever
When do first manifestations occur in Roseola pts?
Describe the onset
How long does the rash last?
First manifestations occur after 5-15 days incubation period
Abrupt onset irritability and fever lasting 3-5 days
Lasts a few hours or up to 1-2 days
Management of roseola?
1. still get a head CT to rule out menigitis if they have seizures
2. nice warm baths will bring down the core temp. 3. Tylenol
How is measles transmitted?
1. Transmitted through nasopharyngeal secretions (directly or airborne droplets) to
2. respiratory mucous membranes or
3. conjunctivae of susceptible persons
How long is measles contagious for?
Highly contagious: infectious from 5 days after exposure to 5 days after skin lesions appear
Clinical presenation of measles?
Whats the prodromal period?
1. Acute febrile eruption following 9-11 days incubation (2 weeks until rash eruption)
Prodromal (lasts 1-8 days; average 3-4d):
1. malaise, irritability, fever (up to 105F),
2. conjunctivitis with increased lacrimation,
3. edema of eyelids,
5. hacking cough,
7. KOPLICK SPOTS (blue white centers)
8. Brick red irregular maculopapular rash that starts on top and goes down
Diagnostic Labs for Measles?
Treatment of Measles?
2. Detection for IgM antibodies with enzyme-linked imumosorbent assay (ELIZA)- when there was outbreak this is what they used
1. Isolation of patient
Rubella is transmitted how?
Whats it caused by?
Why is it dangerous for babies?
1. Nasopharyngeal secretions transmit virus
2. Caused by Togavirus
3. Transplacental transmission results in congenital rubella syndrome
Clinical presentation of rubella?
1. Viral exanthemous primary disease is generally milder than rubeola (measles)
2. No prodromal in children
3. Adults - Prodromal illness precedes rash by 1-8 days and consists of malaise, headache, fever
When does the rash appear in rubella?
Whats the difference in appareance of rash in rubella and rubeola?
14-21 days after exposure and follows same pattern as rubeola
1. Lesions have lighter hue than measles
2. Lesions usually remain discrete versus coalescent form and last 1-5 days (most commonly 3 days)
3. Small red lesions (Forchheimer’s spots) may appear on soft palate (not pathognomonic)
What nodes are most affected by rubella?
post-auricular and suboccipital nodes
Congenital rubella syndrome
1. Heart malformations
2. Eye lesions
4. Mental retardation
6. Thrombocytopenic purpura
8. Intrauterine growth retardation
What are the heart malformations that could occur with congenital rubella?3
1. patent ductus arteriosus, 2. interventricular septal defect,
3. pulmonic stenosis
What are the eye lesions that could occur with congenital rubella?
1. corneal clouding,
Prevention!!! Attenuated virus can be detected up to 4 weeks after immunization
Diagnostic tests for Rubella?
2 and 2
2. Virus isolation and serologic tests of immunity
--Fluorescent antibody tests
--IgM antibodies to Togavirus
Complications of Rubella? 2
Congenital rubella complications?
1. Exposure during PG
2.Post infectious encephalopathy
What kind of virus is mumps?
How is it spread and how contagious is it compared to measles or chicken pox?
Etiologic agent: A paramyxovirus
Spread by respiratory route but less “contagious” than measles or chickenpox
Clinical presentaiton of mumps:
What percent of infections are subclinical?
12-25 days incubation period
At least 25% of infections are subclinical
What is the first indication of mumps and usually occurs very suddenly?
What else is a common clinical presentation in men?
Unilateral or bilateral?
Parotitis: parotid swelling (salivary adenitis) is first indication of illness and usually occurs suddenly
When are the three common cold viruses that were mentioned?
What family are the influenza viruses part of?
What types are based on antigenic characteristics of the nucleoprotein (NP) and matrix (M) protein antigens?
Type A undergoes further classification. Describe this.
Orthomyxoviridae family of viruses
Types A, B and C
Further surface antigenic classification
1. Hemagglutinin (H) antigens (H1-3)
2. Neuraminidase (N) antigens (N1-2)
Major antigenic shifts occurs regularly.
Type A viruses about every how many years?
Type B viruses about every how many years?
Clinical Presentation for Influenza:
What will the onset be like and what will the initial symtpoms be?
These symtpoms are accompanied by respiratory symptoms. What are they? 2
Acute illness generally resolves within?
Abrupt onset of systemic symptoms:
2. fever (38-41 C),
What is evidence of pulmoary complications in influenza pts?
4. diffuse rales or
5. signs of consolidation
Complications that can come from influenza?
1. Pneumonia (most common-staph)
2. Reye’s syndrome (especially children ages 2-16)
3. Myositis, rhabdomyolysis, myoglobinuria
4. Myocarditis and pericarditis
What do we not want to give kids for influenza?
Brain and liver in kids- aspirin, pepto has aspirin in it
What will we see in influenza in the elderly that is different?
mental status change
Diagnosis of Flu?
Symptomatic treatment of Flu (not in first 72 hours)?
1. Rapid flu swab (Nasal, throat)
4. Antibiotics if pneumonia is suspected
If we catch influenza in the first 72 hours we should treat with what?
What are the two alternative drugs?
1. Oseltamivir (Tamiflu)
2. Zanamivir (Relenza)
Adamantane derivatives/M2 inhibitors (proton channel through viral envelope)
Who is the flu vaccine contraindicated in?
Who do we need to make sure have the vaccination every year?
allergy to eggs
1. Chronic cardiac or pulmonary disease (including asthma)
2. Pregnant women
3. Residents of chronic care/nursing facilities
4. Over age 65
5. Chronic medical disorders: DM, renal disease, hemoglobinopathies, immunosuppressed
6. Individuals who care for high risk populations
What is a member of the Paramyxovirus genus is a major respiratory pathogen of young children?
How is it transmitted?
Incidence rates are highest in what age group?
Respiratory syncytial virus (RSV)
Transmitted primarily by close contact with contaminated fingers or fomites
Why is RSV so deadly to babies?
What is one thing you must do doing the physical exam?
1. The infection happens deep in the bronchioles and causes tons of inflammation
2. little babies can’t cough it out and they dont get any oxygen
Clinical presentation of RSV in infants:
Commonly presents initally how?4
Severe illness presents how?5
Clinical presentation in adults?
Younger children? 3
Commonly presents as
2. low-grade fever,
3. cough and wheezing,
4. mild systemic symtoms
4. cyanosis even apnea may ensue
5. Diffuse wheezing, rhonchi and rales
Adults/older children - common cold presentation
Younger children/infants - bronchiolitis, tracheobronchitis and pneumonia
Diagnostic tests for RSV?
1. Rapid RSV with nasal washings using viral antigen ID using and
2. ELIZA or immunofluorescent assay
3. Culture of nasaopharyngeal secretions
Antiviral therapy: Ribavirin
1. Contact isolation
2. Respiratory therapy, oxygen, secretion removal
4. Antibronchospastic agents
There are 4 major serotypes of croup. 3 are important. What do they cause?
What kind of virus is it?
Caused by the parainfluenza viruses: 4 major serotypes
Type 1 is most frequent cause of croup (laryngotracheo-bronchitis) in children
Type 2 is similar but less severe disease
Type 3 causes bronchiolitis and pneumonia is infants
1. Acute febrile illness in children (50-80%)
2. Coryza, sore throat, hoarseness and variably croupy cough
3. Breathing difficulty accompanied by a "barking" cough.
4. Croup is much worse at night
Management of croup? 2
ER treatment? 2
What treatment should we avoided?
What if the cough is going on for a long time?
1. Cool or moist air can bring relief.
1. Aerosolized Racemic Epinephrene
2. Predisone in ER and to go (oral)
Avoid cough medicines (supress cough, not your goal want to get rid of the information)
What virus causes rabies?
What are the two epidemiologic forms?
Clinical presentation of rabies is divided into 4 stages.
Stage one description? 2
Prodrome usually persists 1-4 days
1. Fever, headache, malaise, myalgias, increased fatigability, anorexia, nausea/vomiting, pharyngitis, nonproductive cough.
2. Paresthesias and/or fasciculations around site of inoculation suggestive of rabies
Clinical presentation of rabies is divided into 4 stages.
Stage two description? 4
1. Development of excessive motor activity, excitation and agitation
2. Confusion, hallucinations, combativeness, muscle spasms, meningismus, seizures and focal paralysis quickly follows
3. Hyperesthesia with excessive sensitivity to bright light, noise or touch is common
4. Fever (up to 105 F), dilated irregular pupils, increased lacrimation, salivation, perspiration, and postural hypotension occur
Clinical presentation of rabies is divided into 4 stages.
Stage three description? 4
Stage four description? 1
Profound brainstem dysfunction
1. Occur shortly after onset of encephalitic phase
2. Difficulty swallowing (with increased salivation) produces characteristic “foaming at the mouth”
3. Violent involuntary contractions of diaphragm and accessory respiratory, pharyngeal and laryngeal muscles
4. Coma and respiratory failure follow
Quick description of the four stages of rabies?
What is the first thing we do if we suspect rabies?
1. Prodrome: usually persists 1-4 days
2. Acute encephalitis
3. Profound brainstem dysfunction
4. Recovery (rarely)
CLEAN THE WOUND FIRST AND FOREMOST
Management for rabies:
Prevention pre and post exposure?
1. Isolation of virus (saliva, CSF or brain tissue)
2. Indirect serologic evidence of immune response
3. Direct antigen detection (skin or brain biopsies)
Post-exposure prohpylaxis is the IG antibody
What is structurely the most complex of any virus?
Differences in Variola Versus Varicella:
Rash starts where?
Lesions occur how?
Depth of lesions?
Present on palms or soles?
More rash on back or abs?
Multiloculated or Uniloculated vesicles?
Rash starts face
Lesions same stage
Back > Abdomen
Rash starts trunk
Lesions in crops
Back = Abdomen