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53 Cards in this Set
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This negative ssRNA enveloped virus is a true zoonoses, and has 5 genes and 8 proteins, and has hemagglutinin on its envelope.
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Rhabdovirus -> Rabies
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The route of infection for this virus is inhalation, organ transplant, or bite of a rabid animal
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Rabies - rhabdovirus. SsRNA-. Virus replicates at wound site and slowly migrates up axons to CNS. CNS gives off descending infection to eyes, skin, salivary glands
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There are 4 phases of rabies, what are they?
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1. Prodromal - fever, headache, sore throat, fatigue, nausea. Often undiagnosed. Must give post-exposure vaccine before this.
2. Sensory - photophobia, anxious, belligerant 3. Excitement: Spasms, tonic contractions, beligerance. Acute encephalitis, siezures. 4. Paralytic - virus killed nerves, brainstem encephalitis = cannot swallow, foam at mouth. Death from respiratory dysfunction. |
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How do you treat rabies?
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Cleanse + debride wound, pour hyperimmune rabies serum onto wound, give rest to patient. Post-exposure vaccine, series of 5, started before CNS involvement. THIS IS THE ONLY VACCINE WE USE POST-EXPOSURE.
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What is the only vaccine we use post-exposure?
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Rabies. Series of 5 that must be started before prodromal stage. There is only one antigenic varient worldwide.
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Where is rhabdovirus found?
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Endemic in wild nimals, dogs, cats, skunks, raccoons, bats. Either you get bitten or inhale feces.
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How do you diagnose rabies?
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Symptoms and hx of bite.
IMMUNOFLOUR ID of rabies antigen in skin biopsy. Negri bodies in tissue samples of brain and spinal cord are classic. Serology will demonstrate rising antibody titers. |
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These two ssRNA negative viruses are very similar
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Orthomyxovirus and paramyxovirus
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What are the four types of disease caused by paramyxovirus?
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Measels
Mumps Parainfluenza Respiratory Syncytial Virus |
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SSRNA negative
Non-segmented Helical enveloped with HN and F No shift and drift |
Paramyxovirus - all of them
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This paramyxovirus is acquired from contaminated aerosols of NP secretions, kills infected cells, and has characteristic Koplik's spots
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Measels. Symptoms appear 10 days after exposure. Get cough, fever, lymadenopathy, Koplik's spots BEFORE RASH, rash, and occasional CNS involvement. Encephalitis can occur, with necrosis of neurons and demyelination (1/500 cases)
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What does the measels rash look like?
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Starting within a day of kopliks spots, it starts at head, moves to trunk, down to leg. Called rubeola.
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What is a rare but horrible side effect of measels?
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Subacute Sclerosing Panencephalitis. Due to chronic infection of CNS, appears 2-10 years after infection, and is fatal.
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What is the vaccine for measels?
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A live attenuated virus, leading to lifelong immunity, given 13-15 months. NOT to pregnant or immunocompromised people.
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How do you diagnose and treat measels?
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Dx is based on clinical findings, can to flourscence of urine or pharyngeal cells.
Tx is supportive and treat secondary bacterial infections |
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At what time of year to we often see measels?
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winter and spring, limited to non-immunized groups. Worldwide. will cause fetal death.
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This ssRNA negative paramyxovirus' initial infection comes from aerosols, and then disseminates by blood to target tissues like parotid gland, CNS, kidneys, ovaries, or testes
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Mumps. The salivary gland swelling comes from desquamation of epithelial cells followed by cellular infiltration.
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3 weeks after exposure, mumps virus can result in the following symptoms
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Swelling of salivary glands, meningitis, orchitis (post pubertal male), oophoritis
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What type of vaccine is used for mumps?
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Live attenuated virus - lifelong immunity (also occurs after infection). Recommended for infants 1+yrs.
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This SSRNA negative virus is non segmented and is a single antigenic type that is highly infectious and occurs in late winter and spring.
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Mumps paramyxovirus
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How do you diagnose and treat mumps?
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Lab dx rare, can use NP swabs and urine and do direct immunoflourescence. PRIMARILY CLINICAL DX.
Treatment based on symptoms. |
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What type of virus is parainfluenza?
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A paramyxovirus, ssRNA negative non segmented helical virus.
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How many antigenic types of parainfluenza are there?
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4 antigenic types (1-4), with infections happening primarily in fall and winter.
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What does parainfluenza cause?
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CROUP. Life threatening inflammation and swelling of bronchi in children less than one. Get URT infection, coryza, rhinitis, fever, can progress to pneumonia. croup causes strydor, a distinct barking cough.
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How is parainfluenzavirus maintained in nature?
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Animal reservoirs, like domestic cattle.
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How do you diagnose parainfluenzavirus?
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This paramyxovirus is diagnosed based on clinical findings primarily. Can do immunoflourescing.
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How do you treat croup?
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No methods right now, just supportive. Immunity is only transient, so no vaccine, can get reinfection.
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This paramyxovirus is the single most serious cause of bronchitis and pneumonia in infants
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Respiratory Syncytial Virus, 15% mortality in those with congenital disease/immunocompromised. A big problem in the NICU.
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What is so different about RSV compared to the other paramyxoviruses?
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No HA as a membrane glycoprotein, instead has G and F.
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What happens with an RSV infection?
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Prodromal sx = URT, ilness progresses to bronchiolitis or pneumonia, get cough, wheezing, respiratory distress and
HYPEREXPANSION of the lungs. Immunity is only transient. |
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What causes death in RSV?
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Respiratory and heart failure, bacterial infection
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What treatments are used for RSV?
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Respigam - Human RSV Ig - IV, prophylactic (1dose/season). Doesn't prevent infection but reduces severity.
Treatment of secondary infections. NO vaccine, initial one caused worse disease upon second infection. Palivizumab - monoclonal Ab. Dx based on clinical findings. |
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This SSRNA negative helically enveloped virus has HA and NA, with M protein to anchor them into lipid bilayer. It also contains 8 genes
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Orthomyxovirus - INFLUENZA.
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Genetic Drift
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A small mutational change, resulting in an epidemic of flu. Occurs with HA and NA.
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Genetic Shift
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Reassortment. Animal and human strains co infect a third party cell and pop out a completely new strain. Could also be an adaption of animal strain to human. Only seen in influenza A, creates Pandemics. Occurs in HA and NA
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Name 3 types of flu that occured due to antigenic shift
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Spanish Flu H1N1
Asian Flu H2N2 Hong Kong Flu H3N2. Flu from drift = H9N2, China (?) |
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How does the flu virus enter a cell?
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Hemagglutinin attaches at neuramic acid residue of host cell, neruamidase cleaves hemagglutinin, enters cell by pinocytosis, acid environment activates M2 ion channel protein and transcription occurs.
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In this virus, transcroption occurs, replicates inthe cytoplasm except for step where 5' is added to mRNA in the nucleus
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Orthomyxovirus
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What kind of disease does orthomyxovirus cause?
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Acute respiratory disease, damagining respiratory epithelium and cilia, increasing susceptibility to bacteria. NA actually disrupts mucin exposing sialic acid sites.
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Group A Flu causes what kind of illness?
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Usually a mild febrile illness. Death can result from complications like pneumonia or Reyes syndrome. Group A is the only group known to infect other mammals and birds. Group A causes pandemics. Group B is endemic.
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What is Reyes Syndrome?
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Vomiting, lethargy, stupor, coma, fatty liver, hyperactive reflexes, seixures, pneumonia associated with acetosalicilic acid (aspirin). Seen in children.
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What goes into making the flu vaccine?
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Normally, a trivalent vaccine is selected each year, with 2 group As and 1 group B influenza. Given to debilitated and elderly. It is attenuated, grown in eggs.
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What is amantidine?
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A prophylaxis used for those allergic to flu vaccine or given during period before vaccine is effective. It is an ion channel blocker. Rimantidine is effective against group A if given early, and has less side effects than amantidine.
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How is the flu diagnosed?
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Rapid dx made by NP aspirate and throat washing iwth ELISA and PCR. Serology is retrospective, but gives type specific dx.
Detection of a 4 fold increase in Igg at two different points in time. Type = M and nuclear protein Strain = NA and HA |
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What is Tamiflu?
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A neuramidase inhibitor (Zanamivir Oseltamivir) that is highly effective with few side effects. Against orthomyxovirus. (influenza)
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IgA is the most important part of immunity towards this ssRNA negative virus that shows shift and drift
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Orthomyxovirus (influenza).
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This SS circular RNA negative virus has 2 segments, is zooitic, and is shed from urine of infected rodents
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Arenavirus. Causes Lassa Fever, Junin Virus.
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How do you treat arenavirus?
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Ribovirin, only works prior to symptoms.
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What does arenavirus do?
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Causes meningitis and hemorrhagic fever. It is present in US, S. America, Africa, and replicates in numerous organs.
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This ssRNA negative virus is characteristically filamenotous and patient who contracts it usually dies
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Filoviridae = Ebola and Marburg Virus
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How is ebola or marburg contracted?
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Human to human, maybe animal to human but no animal reservoir found.
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What are the symptoms of filovirus?
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Fever, headache, joint and muscle ache, sore throat, diarrhea, vomiting, stomach pain, HICCUPS, red eyes, internal and external bleeding. This is MARBURG or EBOLA.
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This SSRNA negative circular virus family has 3 segments, G and N glylcoproteins, and zoonotic.
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Bunyaviridae - including bunyavirus, phlebovirus, nairovirus, tospovirus, CA Encephalitis, and Hantavirus. They all have arthropod vector except hantavirus.
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