WEEK 15 SSRNA

Arenaviridae

Bunyavridae

Caliciviridae

Coronaviridae

Filoviridae

Flaviviridae

SsRNA

Arena

It means “sand”

Arenaviruses

Under an electron microscope, ______ appear sandy and granular (ribosomes)

Arenaviridae

Enveloped, segmented ssRNA

Arenaviridae

Includes many species that cause hemorrhagic fever

Old world

New world

Two groups of arenaviridae

Tacaribe Amapari Cupixi Parana

Latino

Pichinde Tamiami Flexal Oliveros Whitewater Arroyo

Pirital Bear Canyon

Allpahuayo

Catarina Pampa

Skinner Tank

Chapare viruses

New world (viruses)

Junin virus (arenaviridae)

Argentine hemorrhagic fever

Machupo (arenaviridae)

Bolivian fever

Sabia (arenaviridae)

Brazilian fever

Guanarito virus (arenaviridae)

Venezuelean fever

Lymphocytic choriomeningitis (LCM) virus

Lassa fever virus

Old world complex

Lymphocytic choriomeningitis (LCM) virus

Can be asymptomatic

Causes influenza-like illness

Lymphocytic choriomeningitis (LCM) virus

About 25% of infected patients develop meningitis

MOT: inhale the aerosolized virus, contact with fomites

Lassa fever viruses

Mostly asymptomatic

Causes influenza-like illness as well as severe hemorrhagic fever; CNS involvement includes seizures and encelopathy

Lassa fever viruses

MOT: inhale the aerosolized virus, contact with fomites, person-to-person, sexual contact, nosocomial

Arenavidae

Infect rodents and humans

Family muridae of rodents

Arenaviridae

Notable reservoir: pet hamsters

Urine

Feces

Saliva

(Arenaviridae) rodents are infected for long periods and typically do not become ill from the viruses, which they shed in:

Serology

RT-PCR

Cell culture (inconsistent sensitivity)

Method of diagnosis of arenaviridae

Supportive

Treatment for LCM is ____

Ribavirin

Treatment for lassa virus is:

Arthropod-borne viruses

Aka arboviruses

Arboviruses

Taxonomically heterogenous but were once grouped together because of their common mode of transmission

Blood sucking

MOT of arthropods

Bunyarviridae

Flaviviridae

Reoviridae

Togaviridae

Arboviruses (4)

Arboviruses

Vector acquires a lifelong infection

Found in all temperature and tropical zones; named after a disease or after geographic area

Arboviruses

Clinical syndromes:

• fevers of an undifferentiated type (w/ or w/out a maculopapular rash)

• Encephalitis

• Hemorrhagic fever

Bunyaviridae

First detected virus in bunyamwera uganda

Bunyaviridae

Enveloped: three, ssRNA, segments enclosed in a helical nucleocapsid (tripatite genome—unique; reassortment)

Bunyaviridae

Transmission: mosquito, tick, and sandfly vectors (except hantaviruses)

Orthobunyavirus

(Bunyaviridae)

• california encephalitis

• La crosse (LACV)

Phlebovirus

(Bunyaviridae)

• rift valley fever

• Sandfly fever

Nairovirus

(Bunyaviridae)

• crimean congo hemorrhagic fever)

La crosse virus (LACV)

California encephalitis virus complex

Orthobunyavirus (bunyaviridae)

Mostly asymptomatic; disease is typically mild and self-limiting

• rates are underestimated

Summer flu

Summer cold

LACV: commonly found in children; referred to as the ____ or ______

Orthobunyavirus (bunyaviridae)

Severe, fatal encephalitis in 2% of infected patients

Orthobunyavirus (bunyaviridae)

MOT: aedes mosquitoes (blood meals)

Reservoirs: rodents, birds

Rift valley fever (phlebovirus)

Targets domestic livestock (zoonotic)

Mosquitoes: aedes specie

Rift valley fever (phlebovirus)

Humans are secondarily infected during the course of epizootics in domesticated animals

• contact with infected animal blood

• Body fluids

• Mosquito bites

Rift valley fever (phlebovirus)

Clinical manifestations - mild febrile illness

Complications:

• retinitis

• Encephalitis

• Hemorrhagic fever

• Permanent loss of vision may occur

• Death in 1% of patients

Rift valley fever (phlebovirus)

Exist in most countries of sub-saharan africa

Outbreaks

• 1977 egypt

• 1987 west africa

• 1997 east africa

• 2000 yemen and saudi arabia

Sandfly fever (phlebovirus)

Phlebotomus fever or pappataci fever

Common in childhood

Large outbreak can occur

Sandfly fever (phlebovirus)

Mistaken for malaria

Phlebotomus papatasii

Female sandfly

Sandfly fever (phlebovirus)

Characteristic

• small itching skin papules

Symptoms

• headache, malaise, nausea, fever, photophobia, stiffness of the neck and back, abdominal pain, leukopenia

Sandfly fever (phlebovirus)

No specific treatment

Use of insect repellents and insecticides

Crimean congo hemorrhagic fever

Infects the vascular endothelium and liver; ticks

High mortality infection in humans; reported nosocomial transmission

Crimean congo hemorrhagic fever

CM:

• begins with fever, myalgia, arthralgia, photophobia

• Mental status changes

• Petechiae and ecchymoses

• Bleeding from bowel, nose and gums

Genus hantavirus

Rodent-borne; transmitted via contact or inhalation of aerosolized rodent excreta

Genus hantavirus

Typically affect the peritoneal cavity, kidneys, thoracic cavity, or lungs

genus hantavirus

hemorrhagic fever with renal syndrome (hfrs)

hemorrhagic fever with renal syndrome (genus hantavirus)

hantaan virus, seoul virus, puumala virus, dobrava virus

hemorrhagic fever with renal syndrome (genus hantavirus)

target kidneys

febrile prodrome, fever and shock, oliguria

1% - 15%

mortality rate for HFRS

hantaan and dobrava viruses

what viruses of genus hantavirus causes severe disease

puumala hantavirus

mild form of HFRS called nephropathia epidemica

genus hantavirus

rodent: apodemus agarius

sin nombre virus

hantavirus pulmonary syndrome

deer mice: peromycus maniculatus

new world hantaviruses

genus hantavirus (new world)

MOT: inhaling contaminated aerosolized mouse urine, saliva and feces

1993: sin nombre (genus hantavirus)

transmitted by inhaling contaminated aerosolized mouse (deer mice) urine, saliva, and feces

1993: sin nombre (genus hantavirus)

causes hantavirus pulmonary syndrome 9HPS)

genus hantavirus

3 to 5 days febrile prodrome, with fever, chills, and myalgia

genus hantavirus

px then enter a phase of hypotensive shock and pulmonary edemal; then develops tachycardia, hypoxia, and hypotension

severe cases: DIC

genus hantavirus

mortality rate: 50%

treatment: primarily supportive

hantavirus pulmonary syndrome

• fever, chills, myalgia

• hypotensive shock and pulmonary edema

• tachycardia, hypoxia, hypotension

• no signs of hemorrhage

• sever cases: DIC

caliciviridae

naked, icosahedra

non-segmented, linear (+) ssRNA

formerly included hepatitis E virus

caliciviridae

important agents of viral gastroenteritis in humans

noroviruses

most significant member of caliciviridae

norwalk virus

prototype strain of noroviruses

norovirus

sapovirus

nebovirus

lagovirus

vesivirus

5 genera of caliciviridae

norwalk viruses

sapporo-like viruses

bovine enteric viruses

rabbot hemorrhagic disease virus

vesicular exanthem virus of swine, feline calicivirus, and marine viruses

norovirus

sapovirus

nebovirus

lagovirus

vesivirus

becovirus

recovirus

newly proposed caliciviridae

norovirus

sapovirus

human caliciviruses

norovirus (norwalk virus; caliciviridae)

most important cause of epidemic viral gastroenteritis in adults

norovirus (norwalk virus; caliciviridae)

cause outbreaks of acute gastroenteritis in schools, colleges, nursing homes, families, cruise ships, resort

norovirus (norwalk virus; caliciviridae)

MOT: foodborne (primarily); waterborne and person to person transmission can be significant

norovirus (norwalk virus; caliciviridae)

diagnosis:

• RT-PCR (most commonly used for stool, vomitus, and environmental samples)

• EIAS

24-48 hours

incubation period of: norwalk viral gastroenteritis (caliciviridae)

norwalk viral gastroenteritis (caliciviridae)

symptoms:

• diarrhea, nausea, vomiting, lo-grade fever, abdominal cramps. headache, malaise

most common cause:

• dehydration

sapovirus (sapporo virus: calici)

1977, sapporo japan

small, with cup-shaped morphology

sapovirus (sapporo virus: calici)

causes diarrhea and vomiting

• infants, young children, older patients

caliciviridae

MOT:

• fecal oral ropute via contaminated food or water

• shellfish associated gastroenteritis

• fomites

• person to person contact

• aerosolization of vomitus

caliciviridae

outbreaks:

• cruise ships, resort areas, schools, colleges, and nursing homes

caliciviridae

lab diagnosis:

• viruses CANNOT be grown in culture

• RT-PCR: most widely used technique(stool, vomitus, environmental samples)

• electron microscopy (stools)

• ELISA

caliciviridae

treatment and control:

• effective handwashing

• disposal of stool samples

• containment and disinfection of soiled areas and bedding

• careful processing of food

• drinking water and pool purification

no vaccine available

coronaviridae

linear, non-segmented,LONGEST known (+) sense RNA genome

coronaviridae

helical nucleocapsid

pleomorphic, enveloped

club-shaped, or petal projections: solar crown

coronaviridae

infect: human, dogs, cats, rodents, bats, and poultry

2nd most prevalent cause of COMMON COLD

alphacoronavirus

betacoronavirus

torovirus

gammacoronavirus

bafinivirus

5 genere of coronaviridae

alphacoronavirus

betacoronavirus

torovirus

genera of coronaviridae that infect HUMANS

coronaviridae

• cold-like infections in adults and pediatric diarrhea

• high concentrations in the nasal passages

coronaviridae

lab diagnosis:

• extremely fatigue and difficult to culture

• immunofluorescence

• electron microscopy

• EIA

• westernblot

• RT-PCR (most common)

severe acute respiratory syndrome (SARS: corona)

pandemic respiratory disease

civet cat to humans

high fever, pneumonia, ARDS

no vaccine or antiviral agent available

SARS-COV

causative agent of: 2002, guandong, china, and hong kong

2006 rocky mountainregion, USA (corona)

bats:

• eptesicus fuscus

• myotis occultus

2006 rocky mountainregion, USA (corona)

target: epithelia cells of GI tract

2006 rocky mountainregion, USA (corona)

MOT: direct cotnact, droplet, or airborne

2006 rocky mountainregion, USA (corona)

affects: spleen, lymphnodes, digestive and urogenitak tracts, CNS, bonemarrow, and heart