Microbiology Test 4 - Viral Diseases I and II

HSV 1 and HSV 2 manifestations

(tissue tropism example) HSV 1 - above waist - oral herpes cold sores on lips cold sores on gums = gingivostomatitis ocular herpes = herpes keratitis = major cause of blindness in young people whitlow = on fingers (dentists) HSV 2 - below waist genital herpes neonatal herpes - transmission to newborn that can result in mental impairment, blindness, convulsions, fatality --- C-section and antiviral recommended for pregnant women with herpes

Common Cold pathogenicity/virulence factors

- binding pocket (like spike) on capsid recognizes iCAM-I on surface of host cell, binds and triggers endocytosis of rhinovirus - some immunity can be acquired against serotypes (number of infections decreases with age) - body fights infections with interferons and specific immune response (cell mediated and humoral)

All the viral disease we will look at and what tissue trophism they have Pneumotropic - respiratory Dermotrophic - skin Viscerotropic - internal organs Neurotrophic - replicate in nervous tissue

----------Pneumotropic - respiratory---------- Rhinoviruses, Adenoviruses, Coronaviruses (common cold) respiratory syncytial disease influenza -----------Dermotrophic - skin------------- HHVI simplex 1, HHV2 simplex 2, HHV3 varicella-zoster, HHV4 - Epstein-Barr (herpesviridae) HPV human papilloma virus - Warts ---------Viscerotropic - internal organs---------- Yellow Fever, Mononucleosis, Hepatitis A and B, Ebola -----Neurotrophic - replicate in nervous tissue---- West Nile Virus, Rabies

Hepatitis B types of viral particles diagnosis treatment

1) Dane particles = virions (infectious) 2) Spherical particles (membrane particles) 3) Filamentous particles (membrane particles) antibodies get soaked up by noninfectious membrane particles bc they all have the same surface antigen diagnosis detecting presence of viral antigens treatment/prevention none/vaccination and safe sex

Human herpesvirus 3 (Varicella-Zoster) - pathogenicity and treatment/prevention

1) infects respiratory tract, skin, or eyes resulting in malaise 2) travels through bloodstream to peripheral nerves and skin where it actively replicates on skin/cutaneous tissue 3) little itchy vessels of viruses appear 2-3 weeks after infection 4) can be treated with topical acyclovir and prevented with attenuated virus vaccine

influenza - types

A - infect variety of animals but wild birds are natural hosts (subtypes named based on type of hemagglutinin and neuraminidase) - virulent bird flu is type A subtype H5N1 B and C infect humans but don't cause pandemics

influenza - antigenic changes

Antigenic changes are responsible for recurring flu epidemics Antigenic drift - small changes in the virus which occur continually over time (viral RNA-dependent RNA polymerase is error prone and leads to errors in replication) Antigenic shift - abrupt major changes in the virus that can result in new H and N combos not seen yet by humans (happens bc animal human viruses interact on a host)

Human herpesvirus 3 (Varicella-Zoster) - latency and shingles

Hangs out in nerves close to spinal cord nerve ganglia Shingles - activated with emotional or physical stress, travels down nerves, replicates and produces shingles on trunk Can give someone chicken pox, esp people with AIDs.

Influenza pathogenicity/virulence factors

Hemagglutinin (HA) - attachment to sialic acid on ciliated epithelial cells Neuraminidase (NA) - entry/exit, snips sialic acid from carbohydrate on cell membrane so influenza can bud from host virus does endocytosis, replicates, assembles, buds, spreads to nearby cells in 6 hours while infected cells die and slough off (destroy mucosal escalator)

Viscerotropic viral disease infect which organs, and how are they transmitted

Infect - small or large intestines, liver, spleen, blood Transmission - bodily fluids from those infected, contaminated food or drink, arthropods

Common Cold treatment/prevention

block attachment with antibodies in the nose that bind iCAM so rhinovirus can't --> Pleconaril (supposed to prevent viral attachment but not FDA approved) --> Zicam - doesn't work but binds zinc in binding pocket --> Killer Kleenex - tissue sandwich with acidic substance in between as prevention (help not transmit cold) --> Vitamin C - stimulates interferon production by strengthening collagen - limits ability of virus to spread through tissues - prevents neighboring cell infection - clinical studies show minimal benefits --> Wash hands

West Nile Fever causative agent transmission

causative agent (+) ssRNA icosahedral, enveloped virus from Flaviviridae family (like Yellow Fever) transmission >> bird animal reservoir -> mosquito bites bird -> mosquito bites human/horse >> blood transfusions, organ transplants, breastfeeding, pregnancy >> NOT direct contact

Yellow Fever causative agent - mosquito type transmission/endemic to Panama Canal with Walter Reed

causative agent (+) ssRNA, icosahedral, enveloped virion of the Flaviviridae family >>Arbovirus : arthropod borne virus >>> Aedes aegypti as biological vectors transmission >>Endemic to central america, south america, and africa >> transmitted by mosquitos that get the virus from infected mammals >> monkey > mosquito > person >> person > mosquito > person Walter Reed >> prevented deaths by preventing mosquito bites by proving it was the first human disease found to be caused by a virus

Ebola Hemorrhagic Fever causative agent transmission

causative agent >> Ebola virus, Marbug virus >> (-) ssRNA enveloped filovirus (long, helical) >> Level 4 Biocontainment transmission >> natural host unknown but likely bats >> human-human transmission through bodily fluids - high spread to healthcare workers

Rabies causative agent transmission

causative agent >> Rabies virus >> (-) ssRNA virion, complex, enveloped with spikes from Rhabdoviridae family; 5 genes and bullet shaped transmission >> can occur in most warm-blooded mammals >> no rabies in AUS, GB, NZ, HI >> transmitted by fluid (saliva, blood, urine) through direct entry break in skin

Hepatitis A causative agent transmission symptoms

causative agent >> caused by several different viruses, results in acute liver inflammation >> Hepatitis A virus (HAV) - (+) ssRNA, icosahedral, no envelope, picornaviridae family >> heparnavirus (hepatitis RNA-virus) transmission >> fecal-oral, water contaminated, food (shellfish) >> extremely resistant to chemical/physical agents symptoms >> appear 2-4 weeks later (short-incubation) >> initial = anorexia, nausea, vomiting, low-grade fever, tummy pain >> 1-2 weeks later = jaundice

Hepatitis B causative agent transmission

causative agent >> hepatitis B virus = hepadnavirus >> enveloped, single and double stranded DNA; plasmid with piece of one strand missing for genome >> HBV is only DNA virus that causes hepatitis transmission >> virions are shed into saliva, semen, and vaginal secretions >> transmitted when infected body fluids contact breaks in the skin or mucous membranes through needles, sex (STD), mother -> child >> many asymptomatic patients >> association with liver cancer

Infectious Mononucleosis causative agent transmission parthenogenesis

causative agent Epstein-Barr Virus (HHV-4), enveloped, icosahedral dsDNA herpesviridae family transmission oropharyngeal secretions (saliva) parthenogenesis >> virus infects B-lymphocytes (mononuclear WBC) that proliferate --> Downey Cells are swollen lymphocytes >> cell mediated immunity leads to to cytotoxic T cells killing virus infected B-lymphocytes

HPV causative agent symptoms

causative agent human papilloma virus is a non-enveloped DNA virus symptoms >>> small clusters of infected cells overgrow and bulge - warts are small tumors or papillomas that can be removed by freezing >>> over 200 different viruses with different tissue tropisms - plantar warts (bottom of feet), genital warts (condylomata=knob-shaped)

Respiratory Syncytial Disease causative agent

causative agent - Respiratory Syncytial Virus (RSV) part of Paramyxoviridae family - helical, (-) ssRNA, enveloped virus

Influenza causative agent

causative agent - influenza virus is a member of the Orthomyxoviridae family --> 8 separate (-) ssRNA helical genome segments like mini chromosomes (brings RNA dependent RNA polymerase) --> capsid surrounds each segment = ribonucleoprotein --> second capsid (matrix protein) encloses the ribonucleoprotein segments --> lipid envelopes the whole thing

Common Cold causative agent

causative agents - adenoviruses, coronaviruses, mostly rhinoviruses - icosahedral viruses of the Picornaviridae family -> group of (+) ssRNA viruses with >200 serotypes and no envelope -> nose is a target because temp is lower than rest of body -> infections limited to the upper respiratory tract (mucus membranes are cooler - leprosy)

Respiratory Syncytial Disease pathogenicity/virulence factors

cell membranes fuse and form giant multinucleated cells = syncytia which function abnormally, die, slough off

Hepatitis A diagnosis treatment prevention

diagnosis >> check liver functioning, check for HAV abs in serum >> infected can be asymptomatic and contagious treatment >> no alcohol or fried food prevention >> removal of source of outbreaks >> vaccination with inactivated viruses

Rabies diagnosis treatment prevention

diagnosis neurological symptoms (also too late to intervene) treatment clean wound, administer human rabies immune globulin (HRIG), vaccinate with human diploid cell vaccine (HDCV) prevention vaccinate dogs and cats, oral vaccine for wildlife

Respiratory Syncytial Disease diagnosis and treatment

diagnosis - based on signs of respiratory distress and verified by immunoassay treatment - supportive - oxygen, intravenous fluids, fever reducers, IgG against RSV from recently recovered blood donor

Human herpesvirus 1 and 2 - diagnosis, treatment, prevention

diagnosis - lesions treatment - Acyclovir limits duration of lesions and reduces viral shedding (not curative) --> nucleoside analog with missing 3'OH (where you attach next nucleoside blocks) --> thymidine kinase from virus converts nucleoside to nucleotide (or acyclovir to false nucleotide) by phosphorylation of Acyclovir on 5'OH -->virus can't differentiate fake and real nucleoside (our cellular thymidine kinases can = why this is the key to selective toxicity) prevention - wear gloves, abstinence

Human herpesvirus 3 (Varicella-Zoster) - causative agent

dsDNA icosahedral enveloped virion that causes 2 diseases 1) varicella (chicken pox in kids usually) (little vessel) by respiratory droplets or skin contact with pox 2) Herpes zoster (shingles in adults usually on trunk)

Example of Antigenic Shift

example bird flu - type A (virus 1 is highly contagious with low mortality; only infects humans) (virus 2 human to human transmission is low and mostly infects birds; high mortality) 1) virus 1 and 2 infect chicken farmer host cell at the same time 2) budding viruses yield combinations that might have bad properties of both viruses -> pandemic like WWI spanish flu (60M die instead of 16M in WWI dying fighting)

Influenza - Complications

flu patients are susceptible to secondary bacterial infections due to virally produced damage to lung epithelium Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae (normal flora infections) Guillain-Barre Syndrome - paralysis, nerve damage, coma Reye's Syndrome - kids who had the flu and took aspirin (give ibuprofen instead) - elevated fever, vomiting, lethargy, glassy eyes, incoherence (complications mostly with young, old, and immunocompromised)

Herpesviridae generalities latency types

generalities - most common DNA viruses --> enveloped, polyhedral capsids and linear dsDNA viruses that enter host cells by membrane fusion before integrating into genome often latent - remain inactive inside infected cells and get reactivated (doesn't recombine into host cell genome) (human herpes virus) HHV1 - herpes simplex 1 HHV2 - herpes simplex 2 HHV3 - varicella-zoster HHV4 - epstein-barr (viscerotropic)

Ebola Hemorrhagic Fever parthenogenesis

parthenogenesis A. Direct infection/replication in monocytes and macrophages causes the release of cytokines associated with inflammation and fever B. infection of endothelial cells that line blood vessels damage endothelial barrier causing cells to detach, die, vascular instability (blood loss), and shock/seizures

Rabies pathogenicity

pathogenicity >> virus enters through tissue from saliva of animal >> viral replication in muscle tissue near bite then moves up PNS to CNS undetected by immune system >> virus moves up spinal cord to brain and causes fatal encephalitis/delusion >> virus moves down and enters salivary glands and other organs

Yellow Fever pathogenicity symptoms treatment/prevention

pathogenicity >> virus travels in blood to lymph nodes, multiples >> spreads to liver, spleen, kidneys, heart >> in severe cases, lesions in infected organs -> hemorrhaging = bleeding gums, vomit blood symptoms >> early = fever/chills then nausea/black vomit >> liver damage -> jaundice >> 7.5% mortality treatment/prevention >> no proven antiviral treatment >> attenuated virus vaccine and control mosquito population

Ebola Hemorrhagic Fever symptoms treatment

symptoms >> initial = typically flu-like >> progression -> massive internal bleeding, blood spurts, organs liquify, seizures >> internal bleeding before immune defense - 90% mortality treatment >> vaccine >> Zmapp = monoclonal antibody genetically engineered to make a protein specific antibody to neutralize ebola >> TKM Ebola - 3 small antisense RNAs (like L19 treatment) bind to Ebola RNA to block translation or target mRNA for degradation

Rabies symptoms

symptoms >> initially mild until CNS is involved >> spasms/paralysis of pharyngeal muscles (drippy saliva, difficulty to swallow, hydrophobia), hallucinations, agitation, aggression >> death from respiratory paralysis >> furious rabies - excitable restless animals bite anything >> paralytic rabies - lethargic docile (cat) >> highest morality of any human disease once symptoms have fully materialized

Hepatitis B symptoms

symptoms >> more severe than HAV with long incubation (4wks-6mo) >> initial = fatigue, anorexia, taste changes (no nausea or vomiting) >> later = dark urine, weird colored stools, jaundice >> chronic liver infection/hepatocarcinoma due to liver not making enough bile sometimes >> more likely to get liver damage or cancer

Infectious Mononucleosis symptoms diagnosis connected diseases

symptoms enlargement of lymph nodes, spleen, fever, malaise, sore throat diagnosis >>> take serum from patient and if the antibodies agglutinate horse RBCs; heterophile antibodies appear as a consequences of B-Cell infection >>> presence of large, lobed B-lymphocytes (Downey Cells) connected diseases >>> Burkitt's lymphoma in East Africa >>> Nasopharyngeal carcinoma in South China >>> chronic fatigue syndrome

West Nile Fever symptoms complications treatment/prevention

symptoms >> develops in 3-14 days, virus multiples in bloodstream then travels to brain sometimes (mostly over 50) >> mostly asymptomatic (70-80%) but when non there's fever, headache, nausea, vomiting, swollen lymph glands, skin rash on chest, stomach, back (20%) >> some (1 in 150) get encephalitis or meningitis = stiff neck, disorientation, coma convulsions, vision loss, paralysis, sometimes permanent neurological effects treatment/prevention - avoid mosquitoes

Common Cold transmission symptoms

transmission - aerosols, fomites, most commonly by direct person to person contact symptoms - sneezing, coughing, congestion, rhinorrhea, malaise, sore throat, NO FEVER

Influenza transmission symptoms

transmission - airborne droplets symptoms - 2 day incubation, body aches, chills, high fever, chest pain due to viral invasion of trachea/bronchi, self-limiting disease (7-10 days)

Respiratory Syncytial Disease transmission symptoms

transmission - typically only infect kids/immunocompromised --> leading cause of fatal respiratory disease in infants/kids --> via fomites, hands, respiratory droplets symptoms - fever, runny nose, barking cough, inflammation/bronchial blockage -> weezing, mild cold-like symptoms in teens/adults

influenza treatment prevention

treatment Amantadine (symmetrel) - prevents viral uncoating by neutralizing acidic environment in phagolysosomes/endocytic vesicle Oseltamivir (tamiflu) - blocks baby virus release from host cells prevention vaccine - antigenic variation requires new vaccination with predicted future strains every year -> inactivated/attenuated viruses cultivated on eggs (less severe symptoms)

Human herpesvirus 1 and 2 - epidemiology

usually from active lesion shedding, but can have asymptomatic shedding as well with HHV/HSV2 transmission from close bodily contact through cuts or cracks in mucous membranes - HHV1 = casual child contact - HHV2 = sex ages 15-29

Neurotrophic Viral Diseases - how do they work

viral infections of the nervous system occur more frequently than bacterial and fungal infection --> readily cross blood-brain barrier

Human herpesvirus 1 and 2 - pathogenicity

virions bind receptors on epithelial cells, infect, multiply, and cause infected cells to die and make sores/blisters virus spreads slowly by inducing syncytia; killed eventually by cell mediated response virus becomes latent in nerves and gets reactivated by stress

HPV pathogenicity/virulence factors complications prevention

virulence/pathogenicity >>> HPV can survive on inanimate objects such as mats, showers, toilets complications >>> small percent can become cancerous due to virulence factors that inactivate tumor suppressor proteins --- association with cervical cancer prevention quadrivalent vaccine against 4 types of HPV