Term
| What does positive strand mean? |
|
Definition
| Viral genome functions as mRNA |
|
|
Term
| What does negative strand mean? |
|
Definition
| Negative RNA genome is a TEMPLATE for mRNA |
|
|
Term
| What is the structure of Rhabdoviruses |
|
Definition
| Rhabdo= ROD in Greek- these are BULLET-SHAPED viruses, with a Negative Sense RNA strand, ENVELOPED, helical |
|
|
Term
| What virus is BULLET SHAPED? |
|
Definition
|
|
Term
| How does one typically get rabies? |
|
Definition
| Bite of a rabid animal; inoculation of intact mucous membranes; aerosolization (though bites are most common) |
|
|
Term
| How does rabies promote its own spread? |
|
Definition
| Hypersalivation with heaps of virus in the saliva combined with PROMOTING AGGRESSIVE BEHAVIOR |
|
|
Term
| Where does rabies spread to in the body? |
|
Definition
| Directly to peripheral nerves by binding the nicotinic Ach Receptor OR indirectly into the muscle at the site of inoculation |
|
|
Term
| How does the rabies virus travel? |
|
Definition
| RETROGRADE AXOPLASMIC TRANSPORT to dorsal root ganglion and spinal cord |
|
|
Term
| What virus travels via RETROGRADE AXOPLASMIC TRANSPORT? |
|
Definition
|
|
Term
| Where does the rabies virus go after brain infection? |
|
Definition
| Highly innervated sites like skin, salivary glands, retina, cornea, nasal mucosa- FATAL |
|
|
Term
| What is the principle vector of rabies worldwide? What are the minor animal vectors? |
|
Definition
| DOGS; raccoons, skunks, bats, foxes |
|
|
Term
| What are the classic neurological symptoms of rabies? |
|
Definition
| Hydrophobia, seizures, disorientation, hallucination, paralysis, confusion, delerium |
|
|
Term
| What virus causes HYDROPHOBIA? |
|
Definition
|
|
Term
| What is the laboratory presentation of rabies on microscopy? |
|
Definition
| NEGRI BODIES- cytoplasmic inclusions where viral assembly occurs |
|
|
Term
| Infection from what virus will cause NEGRI BODIES on microscopy? |
|
Definition
|
|
Term
| What is the course of treatment if rabies infection is suspected? |
|
Definition
1 dose of human rabies immunoglobulin (HRIG)
5 doses of rabies vaccine |
|
|
Term
| What are the characteristics of filoviridae? |
|
Definition
Filamentous, ENVELOPED, Negative Sense RNA Virus- helical nucleocapsid
endemic in Africa
-Ebola and Marburg |
|
|
Term
| What are the main sites of tissue damage in Ebola, and what is the end result of the infection? |
|
Definition
Parenchyma of liver, spleen, LN and lungs
-WIDESPREAD HEMORRHAGE THAT CAUSES EDEMA AND SHOCK |
|
|
Term
| How is Ebola transmitted? |
|
Definition
| Airborne to animals; direct contact with blood and other secretions |
|
|
Term
| What are some "fascinating facts" about Marburg Virus? |
|
Definition
| Exposure to African Green Monkeys imported for research and to prepare polio vaccine |
|
|
Term
| What are the characteristics of bunyaviridae? |
|
Definition
Segmented, ENVELOPED, Negative Sense RNA Viruses- helical
-Hanta, Nairo, Phlebo, Bunya
ZOONOTIC |
|
|
Term
| How is Hantavirus spread? |
|
Definition
|
|
Term
| What is the vector for most Bunyaviridae? |
|
Definition
| Mosquitos- can cause encephalitis |
|
|
Term
| Because bunyaviruses are injected directly into blood via mosquitos, how does this effect their pathogenesis? |
|
Definition
| Primary viremia which spreads to target organs including CNS, liver, kidney, and vascular endothelium |
|
|
Term
| What are the neural and CNS complications of bunyavirus infection? |
|
Definition
| Neuronal or glial cell damage, cerebral edema leading to encephalitis |
|
|
Term
| What is the hallmark symptom of Hantavirus infection? |
|
Definition
| MASSIVE PULMONARY EDEMA (Hantavirus Pulmonary Syndrom HPS) |
|
|
Term
| What virus causes MASSIVE PULMONARY EDEMA? |
|
Definition
|
|
Term
| What are the clinical symptoms of Hantavirus infection? |
|
Definition
| Hantavirus Pulmonary Syndrome (massive pulmonary edema); hemorrhagic tissue destruction and lethal complications; FUNCTIONAL IMPAIRMENT OF VASCULAR ENDOTHELIUM; significant leg cramping and pain |
|
|
Term
| What virus causes FUNCTIONAL IMPAIRMENT OF VASCULAR ENDOTHELIUM? |
|
Definition
|
|
Term
| What is the vector for bunyaviruses and where do they breed? |
|
Definition
| Aedes; water treeholes and discarded trees |
|
|
Term
| How are humans infected by Hantavirus? |
|
Definition
| Close contact with rodents or droppings |
|
|
Term
| What are the symptoms of Hantavirus? |
|
Definition
Non-specific presentation with short febrile prodrome lasting 3-5 days
-fever, myalgia, headache, chills, dizziness, non-productive cough, nausea, vomiting
SHORTNESS OF BREATH, TACHYPNEA, TACHYCARDIA |
|
|
Term
| What are the symptoms of progressed Hantavirus? |
|
Definition
| Cardiopulmonary phase- hospitalization is necessary, often with ventilator, to manage TACHYPNEA and TACHYCARDIA |
|
|
Term
| What are the 4 Arenaviridae, and what do they cause? |
|
Definition
LCMV- Lymphocytic Choriomeningitis Virus
Lassa, Junin, and Machupo all cause Hemorrhagic Fever |
|
|
Term
| What is the structure of the Reoviruses? |
|
Definition
| DOUBLE-STRANDED NAKED RNA- reovirus, rotavirus, Colorado Tick Fever Virus |
|
|
Term
| How is rotavirus transmitted, and what does it cause? |
|
Definition
| Fecal-oral; gastroenteritis without blood or pus |
|
|
Term
| How is reovirus transmitted, and what does it cause? |
|
Definition
| Fecal-oral AND respiratory; common cold, gastroenteritis |
|
|
Term
| How is Colorado Tick Fever Virus spread, and what does it cause? |
|
Definition
Ticks- virus infects erythroid precursors;
Flu-like illness, biphasic fever, conjunctivitis, possible rash |
|
|
Term
| What virus causes BIPHASIC FEVER and CONJUNCTIVITIS? |
|
Definition
| Colorado Tick Fever Virus |
|
|
Term
| What are the 3 viruses in the orthomyxoviridae family? |
|
Definition
|
|
Term
| Which influenza virus can be found in animals and humans, and which can be found only in humans? |
|
Definition
INFLUENZA A- ANIMALS AND HUMANS
(Shift can only happen in A)
INFLUENZA B- ONLY HUMANS |
|
|
Term
| Which influenza virus can undergo SHIFT? |
|
Definition
|
|
Term
| What type of viral change causes EPIDEMICS in influenza? |
|
Definition
|
|
Term
| What type of viral change causes PANDEMICS in influenza? |
|
Definition
|
|
Term
| What is the structure of the orthomyxoviridae? |
|
Definition
Negative Stranded ENVELOPED RNA viruses-
8 SEGMENT Genome |
|
|
Term
| What is Hemagglutinin (HA)? |
|
Definition
On the influenza viral envelope- responsible for entry of virus into cells
-BINDS TO N-ACETYLNEURAMIC ACID (SIALIC ACID) ON THE CELL SURFACE |
|
|
Term
| What part of influenza binds to sialic acid on the host cell surface? |
|
Definition
|
|
Term
| What virus has hemagglutinin and what does it bind to? |
|
Definition
|
|
Term
| What is Neuraminidase (NA)? |
|
Definition
On the influenza viral envelope- liquifies mucous in the respiratory tract to allow the virus easy access to epithelial cells
-REMOVES SIALIC ACID from proteins in virus and infected cells |
|
|
Term
| What part of the influenza virus does the new class of flu drugs block the function of? |
|
Definition
| Neuraminidase- prevents ACCESS |
|
|
Term
| What do the nomenclature designations of H and N stand for? |
|
Definition
| Hemagglutinin and Neuraminidase |
|
|
Term
| How many antigenically different flu vaccines are included in the main flu vaccine? |
|
Definition
|
|
Term
|
Definition
The sudden replacement of one flu subtype that has been around for decades with a brand new subtype-
-always involves the HA subtype, but only sometimes the NA subtype |
|
|
Term
| What flu subtype is ALWAYS involved in antigenic SHIFT? |
|
Definition
|
|
Term
| How does antigenic shift occur? |
|
Definition
Only in Type A influenza virus (because they infect animals as well as humans); REASSORTMENT OF VIRAL RNA SEGMENTS WHEN THERE IS COINFECTION WITH 2 DIFFERENT INFLUENZA SUBTYPES
(must have all 8 genome segments together) |
|
|
Term
| What is it called when cells are coinfected with two different influenza subtypes and the RNA segments are reassorted to make a new virus? |
|
Definition
|
|
Term
| What must happen to the viral genome in antigenic shift? |
|
Definition
| ALL 8 PIECES OF THE GENOME MUST BE ASSEMEBLED (FROM 2 DIFFERENT SOURCES) |
|
|
Term
| What is antigenic drift and what types of influenza viruses can use it? |
|
Definition
Mutations in RNA; both types A and B can drift
-small changes in the amino acid sequence of HA and NA |
|
|
Term
| What is the term for small changes in the amino acid sequence of HA and NA in influenza? |
|
Definition
|
|
Term
| What does antigenic drift allow for in a population? |
|
Definition
| Drift in HA allows the virus to circumvent existing immunity in a segment of the population each year |
|
|
Term
| How many antigenic sites on HA are recognized by antibodies, and what happens to these sites during antigenic drift? |
|
Definition
| 4 sites; gradual AA sequence changes occur to allow the virus to avoid antibody recognition |
|
|
Term
| What is the consequence of destruction of ciliated epithelium in viral infections? |
|
Definition
| Like Influenza- the cilia don't work, so stuff doesn't get cleared as well, and it creates a chain reaction with secondary BACTERIAL INFECTIONS |
|
|
Term
| How is the influenza virus spread? |
|
Definition
|
|
Term
| What cells are infected by influenza virus? |
|
Definition
| Ciliated columnar epithelium |
|
|
Term
| How does influenza enter ciliated epithelium? |
|
Definition
| HA binds to sialic acid receptors and the virus is phagocytized |
|
|
Term
| What is the effect of M2 protein in influenza infection? |
|
Definition
| The endosome pH drops to 5.5 because the M2 protein acts as an ion channel in the virus envelope; nucleocapsids are released into the cytoplasm |
|
|
Term
| What viral infection is characterized by ABRUPT ONSET of fever? |
|
Definition
|
|
Term
| What is the progression of symptoms in influenza infection? |
|
Definition
Abrupt onset of fever;
Headache (severe RETROORBITAL pain), myalgia, sore throat, and non-productive cough;
4th day- respiratory symptoms predominate (pharyngitis, laryngitis, and tracheobronchitis);
Cough and malaise may last 1-2 weeks after other symptoms
TOTAL DURATION= ABOUT 1 WEEK |
|
|
Term
| What causes the systemic symptoms in influenza infection? |
|
Definition
| Cell damage initiates acute inflammatory response, and systemic symptoms are due to the release of inflammatory mediators |
|
|
Term
| In what setting is influenza diagnosis particularly important? |
|
Definition
|
|
Term
| What do rapid influenza tests not differentiate? |
|
Definition
| Between influenza A and B |
|
|
Term
| What should not be given to children or adolescents as a treatment for the flu? |
|
Definition
| Aspirin: can cause Reye's syndrome- similar to chicken pox |
|
|
Term
| What antiviral treatments are used against the flu in severe cases? |
|
Definition
Amantadine and Rimantadine: specific activity against TYPE A viruses- they interfere with viral uncoding
-can be used prophylactically, and are best given within 48 hours |
|
|
Term
| How do Neurominidase Inhibitors work? |
|
Definition
Inhibit influenza A and B neurominidase- the drugs are ANALOGS OF SIALIC ACID, so they block the active site of Neuraminidase
-Prevent viral infection of uninfected cells
TAMIFLU and RELENZA
-most effective in the first few days |
|
|
Term
| What type of vaccine is available for influenza? |
|
Definition
Inactivated (killed) or live attenuated- usually given in the late fall before the flu season starts
-Both Type A and Type B vaccines are given concomitantly |
|
|
Term
| What two subtypes of Type A influenza are still circulating currently? |
|
Definition
| H3N2 and H1N1- both are included in vaccine |
|
|
Term
| What is picked each year for the trivalent vaccine? |
|
Definition
One H3N2, one H1N1, and one type B strain
-chosen as the strains most likely to be prevalent in the upcoming winter |
|
|
Term
| What is special about the Paramyxoviridae (measles, etc.) in terms of their action on cells? |
|
Definition
| The can induce cell to cell fusion forming a SYNCYTIA- giant, multinucleated cells |
|
|
Term
| What Negative Sense RNA viral family causes cells to form SYNCYTIA? |
|
Definition
Paramyxoviridae, like measles, parainfluenza, RSV
FUSION PROTEIN IN THE ENVELOPE |
|
|
Term
| Name four viruses in the paramyxoviridae family: |
|
Definition
| Measles, parainfluenza, mumps, and RSV |
|
|
Term
| What virus causes measles, and what are its symptoms? |
|
Definition
| Morbillivirus; rash, high fever, cough, conjunctivitis, coryza (symptoms of a head cold) |
|
|
Term
| What is the pathogenesis of measles? |
|
Definition
| Cell fusion, formation of giant cells- virus passes directly from cell to cell and escapes antibody recognition |
|
|
Term
| How is measles transmitted? |
|
Definition
|
|
Term
| Where does measles replicate, and where does it spread? |
|
Definition
| Respiratory tract; spreads to lymphatics and causes viremia |
|
|
Term
| What are some possible sites of infection due to measles? |
|
Definition
| Conjunctiva, respiratory tract, urinary tract, small blood vessels, lymphatics, and CNS |
|
|
Term
| What is the sneaky thing about the spread of measles? |
|
Definition
| It can be spread in respiratory secretions before AND after the onset of symptoms. |
|
|
Term
| What virus can be spread in respiratory secretions both before AND after the onset of symptoms? |
|
Definition
|
|
Term
| What is the difference in timeframe between German Measles and regular Measles? |
|
Definition
German Measles= RUBELLA= 3 days
Measles Measles= RUBEOLA= Full Week |
|
|
Term
|
Definition
| Caused by Herpes 6- FEVER GOES AWAY, THEN RASH APPEARS |
|
|
Term
| What are the 3C's of measles? |
|
Definition
| Cough, conjunctivitis, and coryza (runny nose) |
|
|
Term
| What are Koplick spots, and in what viral infection do they occur? |
|
Definition
| Look like small grains of sand that appear on buccal mucosa, conjunctiva, or vagina- Associated with MEASLES |
|
|
Term
| What is the relationship between Koplick Spots and the rash in measles? |
|
Definition
| Spots appear before the rash |
|
|
Term
| What characterizes the rash in measles? |
|
Definition
12-24 hours after the appearance of Koplick spots, the measles rash begins BELOW THE EARS and spreads all over the body
MACULOPAPULAR RASH
-FEVER IS HIGHEST ON THE DAY OF THE RASH |
|
|
Term
| Where does the measles rash start? |
|
Definition
| Below the ears, spreads to entire body |
|
|
Term
| What virus causes a maculopapular rash that starts BELOW THE EARS, and the presence of which marks the day that the fever is highest and patient is sickest? |
|
Definition
|
|
Term
| What causes 60% of measles deaths, and what other virus can cause this? |
|
Definition
| Giant Cell Pneumonia- also caused by chickenpox |
|
|
Term
| What characterizes atypical measles? |
|
Definition
Occurs in people that have by vaccinated by inactivated vaccine and have insufficient protection-
-ILLNESS BEGINS ABRUPTLY AND IS MORE INTENSE THAN PRIMARY MEASLES |
|
|
Term
| What is Subacute Sclerosing Pan Encephalitis (SSPE) and what virus causes it? |
|
Definition
-Extremely serious neurological sequelae of measles-RARE
-defective measles virus in the brain acts as a slow virus- it can replicate and spread from cell to cell, but is not released
-changes in behavior, muscle jerks, blindness |
|
|
Term
| What is the diagnostic test for Subacute Sclerosing Pan Encephalitis? |
|
Definition
| High levels of measles Ab in blood and CSF |
|
|
Term
| How is measles diagnosed? |
|
Definition
Usually clinical presentation- difficult to isolate and grow, but can be found in secretions, blood, urine, and brain tissue
-can LOOK FOR GIANT CELLS
-immunofluorescence
-Virus-specific IgM when rash is present |
|
|
Term
| What are the symptoms of paramyxovirus parainfluenzae? |
|
Definition
Mild, cold-like symptoms, but can cause serious upper respiratory tract disease
CAN CAUSE CROUP |
|
|
Term
| What virus can cause CROUP, and what is it? |
|
Definition
| Parainfluenzae (paramyxovirus); SEAL BARKING COUGH |
|
|
Term
| What virus causes a SEAL BARKING COUGH? |
|
Definition
| Parainfluenza- this is called Croup |
|
|
Term
| What is the diagnostic for parainfluenza? |
|
Definition
Isolated from nasal washings and respiratory secretions- SYNCYTIA can be observed by IF
Hemadsorption and hemagglutination |
|
|
Term
| What virus causes acute, benign parotitis? |
|
Definition
|
|
Term
| What virus causes painful swelling of the salivary glands? |
|
Definition
|
|
Term
| What is acute benign parotitis? |
|
Definition
| Painful swelling of the salivary glands, as in MUMPS |
|
|
Term
| What type of infection is mumps, and to what cells does it initially spread? |
|
Definition
| Lytic; upper respiratory tract epithelium |
|
|
Term
| Where in the body does mumps spread? |
|
Definition
| Via viremia to testes, ovary, pancreas, thyroid, and CNS in 50% of cases |
|
|
Term
| What virus causes orchitis and sterility? |
|
Definition
|
|
Term
| What are the reproductive consequences of mumps in males? |
|
Definition
|
|
Term
|
Definition
| Respiratory droplets- usually in younger people |
|
|
Term
| What are the clinical symptoms of mumps? |
|
Definition
BILATERAL parotitis; sudden onset low grade fever, headache, malaise
Oral exam reveals redness and swelling of OSTIUM OF STENSON's DUCT |
|
|
Term
| What virus causes redness and swelling of the ostium of Stenson's duct? |
|
Definition
|
|
Term
| What are the potential complications of mumps? |
|
Definition
| CNS involvement (50%); pancreatitis; deafness; orchitis-sterility; death |
|
|
Term
|
Definition
Virus can be recovered from saliva, urine, pharynx, and CSF
-can grow in culture and look for MULTINUCLEATED CELLS
-4x increase in specific IgM
-Hemagglutination inhibition, ELISA, IF |
|
|
Term
| What is the most frequent cause of fatal respiratory tract infections in infants and young childrean? |
|
Definition
| Pneumovirus: Respiratory Syncytial Virus |
|
|
Term
| What should you immediately think of in a case with an INFANT THAT HAS VIRAL PNEUMONIA? |
|
Definition
| Respiratory Syncytial Virus |
|
|
Term
| What does RSV cause in adults? |
|
Definition
|
|
Term
| Describe the pathogenesis of Respiratory Syncytial Virus: |
|
Definition
Upper Respiratory Tract
Syncytia
Direct viral invasion of respiratory epithelium
NECROSIS OF BRONCHI AND BRONCHIOLES LEADING TO MUCUS PLUGS AND FIBRIN which can block airway |
|
|
Term
| What virus leads to mucus plugs and fibrin that can block the airway? |
|
Definition
|
|
Term
| In what season does RSV almost always occur? |
|
Definition
|
|
Term
|
Definition
On the hands by fomites, and by respiratory routes;
Shed in respiratory secretions for days |
|
|
Term
| What are the symptoms of RSV? |
|
Definition
Ranging from common cold to pneumonia
RUNNY NOSE
Some cases can progress to LRT and cause bronchiolitis in infants;
low grade fever, tachypnea, tachycardia and wheezing |
|
|
Term
| What RESPIRATORY virus causes a VERY SERIOUSLY RUNNY RUNNY NOSE? |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
Supportive care, oxygen, IV fluids
Ribavirin- can be administered as an inhalant
Synagis- Monoclonal Ab against F protein |
|
|
