Th 1 Response

• INF gamma epitomizes Th 1 respone and prevents Th2
• inducers of DCL? and IL-12 production
• IL-2 promotes expansion of imune responses by promoting T, B and NK cell growth 
• important for viruses, intracellular bacteria, fungi, intracellular parasites and tumors
• DCs have to be activated by infection ot get Th1 response
• TLR ligants and TNF beta

Th 17 Response

• immune response in presence of TGFβ, IL-1, IL-6
• IL-23 can activate in gut, rapid response by stimulation of neutrophils (anti bacterial and fungal)(promotes memory)
• negatives are initiation and maintenence of Autoimmune disease (chrohns, rheumatoid arthritis)
• IL-17 is what is released to epithelial cell to produce TNF, IL1, IL6 and activate neutrophils
• IL-17 activates epithelial cells to make antimicrobial peptides and important for anti-fungal
• IL-12 converts responses to Th1 and IL-4 to Th2
• CD4 cells activated by IL-6 and 1 in presence of TGFβ
• excessive Th17 contributes to chronic infl. (rheumatoid arthritis)

Th2 Responses

• No IL-12, instead IL-4 and 5 (also some IL-10)
• promotes growth and class swithc (IgG, A, E)
• antibodies w/o cellular responses
• systemic, not local: vieremia and bacteremia
• IL-5 promotes antibody production and T cell help for antibody class switch
• response to inactivated vaccine
• facilitates worm elimination (IgE and mucous)
• negative aspects: IgE and allergies and inhibits Th1 (bad for mycobacterial infections)

Papillomaviruses

• noneveloped circ dsDNA
• cutaneous (warts, basal ganlgia) and mucosal (low risk and high risk) HPV
• high risk is  HPV 16 and 17
• protein E6 inhibs P53 and E7 Retinoblastoma protein (immortalizing; HPV 16 and 17)
• hallmark: koilocytes (enlarged, wrinkled nucleus)
• PCR and blotting used to diagnose (papsmear
• Vaccine has 10x more antibody production (esp mucosal IgA)

Polyomaviruses

• nonenveloped dsDNA genome 
• rare diseases: PML (JC virus), Neuro prob (BK virus)
• immunosuprresed at most risk
• PML: goes resp, than viremia to kidney, and blood monocells, most infections are asymptomatic and not associated with tumors
• BK: can kill transplant organs (kidney), brain tissue biopsy before, now PCR of CSF for diagnosis
• no good treatment for BK; raise immune system
• both worldwide, BK appears earlier than JC

Parvovirus

• nonenv. linear ssDNA (3 genes)
• smallest DNA virus to cause disease
• must replicate in nuc of activ. dividing cell
• human parvovirus is B19 virus
• this virus makes prominant vacuoles in erythroid precursor cells and they eventually apoptos

B19 Virus

• non enveloped ssDNA Parvovirus
• attaches to erythrocyte P angtigen 
• replication lysis cell (erythropoesis interupt for week)
• recovery correlates w/ IgM and IgG production
• 2-10% under 5; 40-60% adults
• malaria sickle cell, thallasemia patients at risk for enemia from B19
• causes hdrops fetalis or erythema infectiosum (slapped cheeks or 5th cheeks rash)
• diagnose w/ IgM or viral DNA PCR (no vaccine)

Adenoviruses

(intermediate size)

• non env linear dsDNA (codes for viral DNApol)
• viral fiber attachment protein extends from capsid
• attaches to cell w/ CAR receptor
• RNA splicing required for mRNA
• infects Resp, GI and eye (in regional lymph nodes)
• can block IFN and supress MHC I (not tumor causing)
• Resp most common in winter and spring(not epidem)
• age effects presentation of virus (worse in older)
• constant cough and conjunctivitis (pink eye)
• must distinguish from strep: use hemagglutination or DNA alalysis 
• antiviral for ocular inf, none for resp and enteric vaccine for military
• fecal oral, can be in pools

Herpes Viruses

• large enveloped dsDNA
• envelope made in golgi
• produce virus or become latent
• T cell necesary to control infection (causes sympts2)
• active and passive viral escape (against Ab and cells)
• antiviral therapy: DNApol, TK (HSV and VZV)
• HSV, VZV (chicken pox and shingles), EBV, CMV, HHV6 and HHV8

Herpes Simplex Virus

• enters cells by fusion, latent in neurons (LAT-RNA)
• spread y cell-cell, syncytia or lysis
• counteract IFN (PKR), inh DC act, block Ab binding and T cell apoptosis and use latency
• Intranuclear Cowdry Type A inclusion bodies
• whitlow (finger), gladitorum/rugbiorum (on back and chest), kerator conjunctiviis and can disseminate
• Tzanck smear of vessicle fluid used to verify
• A-cyclovirs used (TK and DNA pol inhs), no vaccine
• child, neonates and immunosupr at risk (stress)

Varicella Zoster Virus 

(alpha herpes)

• primary (chick pox) worse in adults
• Chicken Pox: start in lung than spread to skin by T cells, contagious 3 days b4 symps, long term immunity
• Rash for Cpox goes macula, papules, vessicles, pustules and crust
• Zoster: recurrent, virus replicate in entire dermatone, post herpetic neuralgia (pain)
• resp and contact transmission (very contagious)
• confirm with PCR
• live vaccine and new adult vaccine for zoster 
• Varicella Zoster Immune Globulin (VZIG) vaccine (leuk child)
• Acyclovir and (other cyclovirs)

Epstein Barr Virus 

(gamma Herpes)

• lymphotrophic (B cells)
• can be immortalizing (in germinal center) and Lytic
• binds to C3d rec on B cells 
• activated B cells have productive infection and espress EBNAs (1-6)
• Memory B cells have latent infections (antigen stim promotes lytic cycle)
• response is Tcell hyperplasia (contagious mono)
• downey cells are characteristic
• stim viral b cells can make IgM that is a Heterophilic Ab [Paul Bunnel Ag]
• EBV more severe in adults, leukemia/lymphoma in immunosuppresed
• no effective treatment or prevention

Mononucleolus

• Epstein Barr Virus (EBV): Herpes Virus
• swollen glands and exudative pharyngitis
• headache fatigue and fever
• Triad: lymphadenopathy, splenomegaly and exudative pharyngitis
• confirm w/ CBC: hyperplasia and Downey Cells
• best is heterophilic Ab: paul bunnel antigen (sheep, horse, bovine)

African Burkitt's Lymphoma

• Epstein Barr Virus: Herpes Virus
• immortalizes Germinal Center B cells
• malarial asociation
• C-mye oncogene translocation to Ig Promotor
• immunologically invisible tumor cell
• treatable w/ cytoxan

Cytomegalovirus (CMV)

Beta Herpes

• ubiquitous (latent in 50% of population); opportunist
• most common cause of viral disease in AIDS patients
• Broad tissue tropism; mono-like in imunocompetant
• Congenital CMV: neonates are small, hearing loss, retarded, organ and CNS sequale
• can cause activation and rejection in transplant
• Large cell (cytomegaly) and Basophilic (Owl's eye) nuclear inclusion bodies
• asymp and can be STD
• treatment: polymerase inhs: Gancyclovir,Valganciclovir and cidofovir (not nice drugs)

HHV6 

(beta herpes)

• ubiquotos, lymphotrophic
• causes Roseola (slapped face rash)
• 4-7 day incubation, scare mom fever, and than rash (immune response)
• in 1% of population HHV6 is on there telomerase of cells (influences health negatively)

HHV8

(gamma Herpes)

• Kaposi's Sarcoma associated viruses
• stimulates growth of cells by making analogue of growth factor
• only happens in immunosupressed patients (AIDS)
• not ubiquitous (opposite of HHV6)

Picronavirus

• nonenv linear ssRNA (+): codes for viralRNApol, proteases
• polio and rhino are Ig supergene family
• fecal-oral route (most innaparent)
• may spread to liver, bone marrow, spleen and major is CNS (ant horn of spine)
• lytic destruction of nerve cells leads to muscle paralysis (poliomyelitis): brain stem in resp paral.
• Polio, Coxsacki, Echovirus, and Rhinovirus (ICAM attachment in nasopharynx)

Poliovirus

• picornavirus (non env ssRNA +)
• post poliomyeltis syndrome: yrs later new muscle weakness, pain, atrophy and fatigue; theory that surviving cells become overworked
• extensive replication in gut leads to high conc. in stool
• 7-10 day incubation, found in stool for 3-6 weeks
• nasal IgA goes way up in live vaccine

Coxsackie Virus (A and B)

• Picornavirus (linear nonenv ssRNA +)
• Group A: hyperangina, fever, soar throat and tender vessicles in mouth and skin (Rush)
• hand, foot, mouth disease, and accute conjunctivits
• Group B: (for body): pleurodynia, sever chest pain with fever
• myocarditis(some lead to heart failure)
• upper resp infection (esp group A); may be epidemic

Echovirus

• picornavirus (non enveloped ssRNA +)
• leading cause of aseptic meningitis (nonbacterial) 
• long term outcomes of abnormalities or sequelae not found
• genearally young and infants hit most 

Caliciviruses

• non env ssRNA + that is Cl resistant
• fecal oral: also person-person transmission
• Norovirus
• 1-2 day incubation with 1-2 day disease
• most common cause of accute gastroenteritis in humans (all ages)
• high genetic variability leads to poor or not lasting immunity
• dagnosis w/ stool samples and RT-PCR
• almost 50% of food borne illnes (Cruise ships)

Coronavirus (CoV)

• enveloped with Spike (glyco)proteins: can enter GI
• largest ssRNA (+), capped and adenylated
• causes resp (30% of upper resp inf) and enteric
• typically disrupts ciliated epithelium and causes common cold
• 2-3 day incubation than malaise, headache, and rhinorea, sneezing, pos. fever and GI symp
• replication restricted at 37C so limited to Upper resp Tract
• Lasts 7 days
• SARS and MERS is also coronavirus

SARS and MERS

• unlike normal coronavirus, can replicate at 37C so can infect upper and rest of lung (lower)
• epithelial destruction and increased macrophages in lungs; cytokine dysregulation
• Zoonitic origin
• high fever, headache, body ache, diarrhea, viral pneumonia, flu like: rapid progression
• # of viruses increase over 1-2 weeks(incubation) allowing for transmission
• seroconversion (Ab) after 1st week of illness
• treatment is disease control and artificial ventilation

Reoviruses

(rotovirus)

• non-env segmented dsRNA with double capsid
• cytoplasmic replication and results in cell lysis
• immune response againts VP7 and VP4 on outer
• VP6 on inner and used for classification
• winter, person-person (fecal-oral), 2 day incubation
• infects villus cells(absorp)of small intestine and stim enteric NS (enterotoxin NSP4)
• diarrhea can go from mild to fatal (no blood or leuk)
• local Ab prim. protection (memory prevents against severity but not reinfection)
• Triad: Vommiting, diarrhea and high grade fever
• treat w/ fluids and diagnose w/ ELISA
• 2 vaccines: VP7 and VP4

Hypersensitivities

• Type I: Allergies, Th2  cells stim IgE production
• Type II: frustrated phagocytes, opsinization or anomalous activation of recepter by Ab, local autoimmune
• Type II furstrated phagocytes: pemphigus vulgaris (blisters), goodpasturs syndrome (nephritis), and acute rheumatic fever (mycarditis and arhtritis)
• Type III: immune complex formation and trapped complexes, systemic autoimmune, arthus rx and serum sickness
• Type IV: T cells and damage by cytokines or Tcell cytolysis: poison ivy, PPD test, hypersensitivity pneumonitis

Hemolytic Disease of Neworn

• Type II Hypersensitivity
• occurs in Rh - mothers 
• first pregnancy w/ Rh + child creates memory antibodies
• 2nd pregnancy IgG can cross placenta and attack babies RBcs causing anemia
• treat mother with Anti-D titer (anti Rh +) which will kill the babies Rh + before mothers cells mount defense against it 

Type II Hypersensitivity

other diseases

• Frustrated Phagocytes: Pemphigus vulgaris (blisters), Goodpastures syndrome (nephritis), and Acute Rheumaic Fever (mycarditis)
• Ab activating or inhibiting: myasthenia gravis, Grave's Disease (hyperthyroid), pernicous anemia (attacks cells that make Intrinsic Factor that normally allows absorption)

Hypersensitivity Pneumonitis

• Type IV hypersensitivity
• Farmers lung, humidifiers lung, pidgeon breeders lung
• inhaltion of orgainc dust containing spores, thermophilic bacteria, fungi or animal proteins
• ong going type IV reaction leads to granulomata and fibrosis of lungs

Transplant Rejection Types

• Hyper Acute Rejection: prexisting antibody in circ (Type II reaction)
• Acute Antibody Mediated Reaction: Humoral Response
• Acute T Cell Mediated Reaction: Type IV hypersensitivity, treatable (anti-C3D Ab)
• Chronic Antibody Rejection: progressive damage to vascular system, scarring, 10yr donation lifespan
• Graft vs Host disease: immunosuppress if happening

Poxvirus

• large enveloped linear dsDNA (boxcar)
• oval brick shaped w/ dumbell shaped viral core containing DNA
• inside nucleocapsids lacking outer env. may be sequestered into inclusion bodies
• entire pox virus replication happens in cytoplasm
• Virus binds to GAG rec on host cell
• core DNA released into cytoplasm
• early genes produce enzymes for DNA replication
• late genes for structural proteins
• assembly of virus, release by lysis
• Smallpox, vaccina, molluscum contagiousm, monkeypox, orf virus, cowpox

Smallpox

• replicates in upper resp tract, than spreads to local lymph nodes
• asymp viremia on day 3-4, spread to bone marrow, spleen and liver
• 2nd viremia day 8, fever and toxic appearnce
• virus becomes localized in blood vessels or dermis, produce erruption of pocks
• Erruptive phase: lesions on mucous membrane in mouth, tongue, palate and oropharynx; simultaneous outbreak of rash on face, proximal extremities, trunk and distal extremities
• maculas, papules, vesicles and pustules, crust: heal with depigmentation
• vomiting, diarrhea and bleeding
• 30-50% mortality due to coagulopathy, hypotension, multiorgan failure
• Diagnosis: virus formation from fluid of lesions, growth on embryoid eggs, pocks appear or charioallantonic membrane
• vaccinate: during or before first week, Vaccinia immune globulin (VIG)
• antiviral drug (Cidofavir; NT analogue)

Vaccina Virus

(orthopoxvirus)

• used as vaccine for smallpox
• can be spread by close contact
• used as expression vector to produce live recombinant vaccines (hybridized with G proteins of rabies)
• many stories about contact infection
• from people recently vaccinated (military)
• eczema vaccinatum

Molluscum Contagiousum

(molluscipoxvirus)

• chronic localized infection, consists of flesh colored, dome shaped papules on skin; wart like lesions w/ central umbilication
• 2-8 weeks incubation (long compared to others)
• transmited by sex, contact sports, fomites
• effects immunocompromised
• appears anywhere except palms and soles
• char. eosinophillic cytopl. inclusion bodies (molluscum bodies)
• liquid nitrogen, blistering agent and cream used

Monkeypox

• rash similar to small pox, appear comonely on volar surfaces (palms and soles)
• person-person spread; incidental host
• reservoir possibly african rodents (from animal blood or bite)
• fever and pustular rash developed after contact w/ praire dog
• rash, fever, chills, lyphodenopathy (only one), headache and myalgias
• diagnosis w/ virus isolation, PCR , ELISA
• Cidofovir or ST-246
• vaccine using vaccinia

Orf Virus

(pox virus)

• zoonotic (sheep and goat), parapoxvirus endemic to most countries
• infection appears as painless ulcerative or vesicular legion, commonly fingers after occupational exposure
• self limiting in hosts w/ normal immune system
• Bulla caused by orf virus after puncture by a bone or recently slaughtered goat
• lesions are nodular and granulomatous
• histo shows intraepithelial balloning and intracytoplasmic inclusion bodies; ovid cros hatch
• PCR for definite diagnosis
• prevent with barrier and hand hygeine

Cowpox Virus

• related to vaccina virus
• lesions are localized and pustular may resemble mild smallpox
• produces immunity to small pox
• reservoir is rodents
• infections 1st via contact w/ infected teats; now from pet cats, rats and mice
• lesions usually remain localized and self limiting
• lesions are nodular and hemorrhagic
• presence of 2 types of inclusion bodies
• irregular B type inclusion bodies
• LArge, numerous, homogenous, acidophilic A type inclusion bodies
• lesion regress spontaneously; Vacc Ig
• barrier and proper handwashing

Paramyxovirus

• pleomorphic, sometimes filamentous
• enveloped linear ssRNA (-), forms syncytium 
• env has 2 glycoproteins: F and H/HN/G
• uses F protein to fuse viral envelope with cell
• viral attachment proteins interact w/ CD46 and CD150 that are on leukeocytes
• exits by budding
• measles, mumps, parainfluenza, RSV

Measles Virus

(paramyxovirus)

• only 1 antigenic type; short survival in air/objects but highly infections (90%)
• aerosals/nasal secr to resp tract infection, contagious till 2-4 days after rash
• replic in nasopharynx and regional lymph: forms multinucleated giant cells  (syncytia)
• Prodromal period with 3Cs: coryza, conjunctivitis, cough
• Koplik's spots: blue white centsers inside mouth 1-2 days before rash
• Rash: begins on face and head, spreads downward
• 30% have complications w/ common ones being diarrhea, otitis media and pneumonia
• live attenuated vaccine for measles and mumps

Measles Complications

• accute measles encephalitis: virus in CNS and involves autoimmune encephalitis (why we vaccinate)
• Post measles encephalitis: allergic response to measles antigen in CNS
• SSPE: neurological infecation: always fatal
• Measles in malnourished (vit A def): co infection common, severe cases

Mumps Virus

(paramyxovirus)

• resp dorplets, upper resp infection
• viremia infects various tissues (esp parotids)
• fever, malaise and headache 7-10 days
• rapid enlargement of the parotid glands
• increased complications about age 15: orchitis and oophoritis (enlargement) in post pubertal; deafness (usually unilateral and permanent)
• before vaccine it was the leading cause of viral encephalitis

Human Parainfluenza Virus

(paramyxovirus)

• infect resp epithel., 3-6 day incubation and has virus for a month
• HPIVs antigen stable types differ in features and season of attack
• Humagluttinin neuraminidase
• Bronchitis: up resp, malaise, headache, persistant cough (productive after 2 days); self limiting 
• Broncholitis: atelectasis (missing gas fromw hole or part of lung), wheezing, tachypnea (rapid breathing), and cyanosis in severe cases
• Croup: first up resp tract, sore throat, high fever, than lower resp tract producing laryngeal and tracheal spasms; has hoarse barking cough

Respiratory Syncytial Virus (RSV)

(paramyxovirus)

• major cause of lower resp infection; innoculation being nose and eye
• fomites involved in transmision (nosocomial)
• may produce serious illness, even w/ maternal Ab against it (bronchoiolitis; pneumonia)
• Bronchiolitis: mainly infants less than 6 months 
• sharp rise in temp 2-3 days after up resp tract
• necrosis of epith of bronchioles
• lumen of small airways become obstructed w/ dad cells and excess mucus
• repeated infections common
• confirm with IF of nasal wash
• treat with Ribavirin

Orthomyxovirus Structure

• eveloped ssRNA with 8 segments
• Three types: A, B, and C
• Hemaglutinin(HA): binds to host sialic acid, allowing endocytosis into endosome, conform change in HA unleases fusion peptide that allows release of viral RNP into cytoplasm
• nucleocapsid: steals mRNA caps from host mRNA so that host transcribes viral mRNA
• Neuraminidase (NA): elution of virus from infect cell surface and inhibits dumbing
• M2: ion channel active import in virus for pH 
• NS-1: IFN antagonist 
• PB2, PB1 and PA: viral polymerase genes; mutation in genes relevant to viral adaption and virulence 

Influenza Virus

(orthomyxovirus)

• Transmitted by resp droplets to Up resp tract
• cytokines cause most symptoms: can be complic
• direct involv of U and L resp tract accounts for much of illness:: damages bronchial epith (lyses); lowers mucociliary clearence
• Adults: rapid onset, fever, chills, headach, unprod cough, traid (cough, fever, prostration)
• Children: fever, rhinitis and half vomit and diarrhea (uncommon in adults)
• Elderly: confusion, weariness, nasal congestion usually only symptoms
• now bedside test for nucleoprotein antigens
• 2-3 type A vaccine and a Type B: HA protein used
• antiviral drugs in first 48 hours (only type A)

SLE (Lupis)

• ulcerative skin lesions
• LE cell: neutrophil engulfed Ab coated cell nucleus
• autoantiboides: ANA and anti-DNA
• ANA tested on HEp-2 or ELISA (sensitive but not specific)
• Anti-DNA detected by Crithidia luciliae or ELISA (specific but not sensitive)
• Postive diagnosis of 4 positives out of all 11 criteria

Scleroderma

• autoimmune disease
• hardening or thickening of skin
• diffuse or limiting
• organs: Lungs, GI and Kidneys
• CREST variant: calcinosis, Raynuds phenomena, esophageal involvement, sclerodactyly and telangiotasia
• ANA, Nuclear pattern (anti-RNA) used to diagnose
• centromere pattern in CREST on HEp-2 Cells
• SCL70csd-1: anticentromere antibody

Primary Biliary Cirrhosis

• 90% female, usually age 30-35
• pruritis(itchy skin), dark urine and hepatomegaly
• later bone pain, hyperpigmentation and cirrhosis
• associated with CREST and PSS(if one autoimmune disease, increased chance of others)
• Anti-mitoch. Ab (also in App 10-15% of CAH)
• IgM polyclonally increased in 80-90%
• plasma cells in portal region of liver (not assoc with Hep Virus)

Autoantibodies associated w/

Celiac Disease

• Anti-Reticulin Ab
• Anti-Giladin Ab
• Anti-endomysial Ab (immunofluorescence)
• Anti-tissue transglutaminase
• ELISA, IFA and multiplex
• IFA is subjective (microscope), but can see cases others might not

Arbovirus

• enveloped ssRNA (+), vector borne (mosquito)
• local replication in vascular endothelium, lymph; than viremia
• fever, chills, headache, muscle aches; may asymptomatic
• followed by movt to muscles, joints, skin and brain
• if in CNS: neuronal necrosis w/ neurophagia
• most replicate in both arthropod and vertebrate host (can winter in larvae/eggs)
• viral encephalitis possible (children more likely to survive)
• adults have sequelae of paralysis, mental debility and seizure
• equine enceph, western equine and West nile (looks like polio)
• Hemorrhagiv fever: high fever and bleeding in organs, GI and in severe cases shock; diagnose with IgM serology (hard to culture)
• Togavirus and Flavivirus

Togavirus

(arbovirus)

• enveloped ssRNA (+)
• E1 and E2 viral glycoproteins on envelope
• makes polyprotein that gets cleaved: leads to subgenomic transcription to cause less cell stress
• febrile illness, rash, arthritis
• CNS encephalitis
• Rubella and Congenital Rubella

Flavivirus

• arbovirus
• also E1 and E2 viral glycoproteins on envelope (ssRNA+)
• yellow fever
• Alpha virus (Equine Enceophalitis family)
• West Nile dead end in humans but dengue and yellow fever (live vaccine) can go erson to person
• no subgenomic RNA (unlike Toga)
• also Hep C

West Nile Virus

• Flavivirus
• mosquito vector and bird reservoir
• cases down but meningitis and encephalitis is on the rise
• highly neuovirulent strain out there (2003)
• Hemorrhagic Fever? (property of arboviruses)
• Risk Factors: hypertension, imuno suppression and cardiovascular problems
• humans are a dead end host
• meningitis, fever, encephalitis, reversible paralysis, neuroinvasive

Dengue Virus

• Flavivirus: 4 viral serotypes
• sudden onset of fever, headache, myalgia, rash, nausea and vommiting (usually self limited)
• musculoskeletal pain (bonebreak fever)
• severe cases cause shock and death: may be due to secondary serotype infection or inflamation and reduced Cardiac output
• Dengue Shock Syndrome (DSS) and Dengue hemorrhage Fever (DHF)
• urban disease in tropics: humans and A. aegypt (mosquito that bites humans
• major world health problem

Rubella Virus 

• Togavirus (not arbovirus because not vector borne)
• mild childhood rash 
• resp tract infection spread by resp route
• viremia develops
• If infected in first trimester, high probability of Congenital Rubella Syndrome in baby
• no vector: human to human
• also called german measles

Congenital Rubella Syndrome

• rubella infection in first trimester can spread to placenta and fetus
• in fetal infection virus can multiply and damage almost any organ system
• slows rate of cell growth and may help produce chromosomal abnormalities
• severe damage: deafness, blindness, hearing and brain defects (15-30% chance of this)

Bunyaviruses

• enveloped, ssRNA (-); 3 Segments
• uniquely cytocidal for vertebrate cells but not mosquitos
• Large RNA seg (polymerase), Medium (glycoprotein), small (capsid) (allow for reassortment w/ dif strains)
• Lacrosse virus, Hantaan and Sin Nombre

Lacrosse Virus 

• Bunyavirius (orthobunyavirus)
• acute infection; short incubation 3-7 day
• fever, malaise; viremia
• encphalitis and siezures pathogenesis involves viral glycoproteins G1 and G2
• chipmunks and squirels reservoir
• children ( <15) dead end common hosts
• encephalitis in late sumer is suspect
• IgM Ab or 4 fold inc in IgG btw early or late serum
• rapid diagnosis is vital
• give them Abs (supportive care)
• acyclovir and brain biopsy unescesarily done a lot
• prepare family for possible sequelaes

Hantan Viruses

• 3 circ ssRNA (-) seg
• transmission to humans by inhalation or aerosals from infected rodent poop
• bot acute syndromes assocated w/ acute thrombocytopenia and changes in vacular permeability (endothelial)
• Sin Nombre caues Hemorrhagic pulmonary syndrome and cardiopulmonary syndrome
• Hantaan virus causes Hemorrhagic fever with renal syndrome
• not nosocomial

Sin Nombre

• a hantan bunyavirus
• fever, myalgia and abdominal pain
• pulmonary edema and resp failure
• Hemorrhagic Pulmonary Syndrome (HPS): diff primary organ target
• lack of widespread hemorrhage compared to Hemorrhagic fever with renal syndrome
• cardiopulmonary hemorrhage

Hantaan Virus

• hantan virus of the bunyavirus family
• fever, chills, lethargy 
• hemorrhagic and renal failure
• Hemorrhagic Fever with Renal Syndrome (HFRS)
• not nosocomial

Arenaviruses

• spherical envelope, 2 seg ssRNA, ambisense (+/-) RNA on same strand
• virus binds to alpha-dystroglycan; cytoplasmic replication
• mainly rodent hosts, humans accidental (lab and hospital infections reported)
• transmitted by exposure to infected rodent poop
• nosocomial
• 6-20 day incubation
• produce humorrhagic fever w/ necrosis of liver (like yellow fever)
• hemorrhage due to inflammation, not virus 
• Lassa virus, South American arenavirus, lymphatic choriomeningitis virus
• treat Lassa with Ribavirin 

Types of Arenavirus

• Lassa Virus : Lass Fever
• South American Arenavirus : Humorragic Fever mortality 15-30%
• Lymphocytic Choriomeningitis Virus : Meningitis, organ transplant failure and Fetal hydrocephalus