Caliciviridae, Filoviridae, Togaviridae Flashcards
Structure: Small (___), rounded, nonenveloped, single- stranded, positive RNA viruses.
* Cause ___ in humans.
* Previously recognized as major animal pathogens with a broad host range.
* ____ classified in the family of this in the 1990s.
*___ include__ and __ genera.
* Genogroups: ___ anad ___
CALICIVIRIDAE
-30-38 nm
- acute gastroenteritis
- Noroviruses (formerly Norwalk-like viruses)
- Human caliciviruses (HuCVs)
- Norovirus and Sapovirus
- Norovirus (I, II, IV) and Sapovirus (I, II, IV, V)
Approximately 685 million cases of gastroenteritis caused by __ annually.
* About 200 million cases occur in children under 5, leading to 50,000 to 70,000 deaths yearly, mostly in developing countries.
* Major public health concern in both low- and high-income countries.
* MOT: Rapid spread due to ___, low infectious
dose (____), and high environmental stability.
* Easily transmitted via food, water, person-to-person contact, and airborne droplets.
* Virus persists in water despite treatment processes
CALICIVIRIDAE
Norovirus
fecal-oral transmission
<100 virus particles
Moderate to severe gastroenteritis: ___,___,___,__ anad ___
* Symptoms typically appear __ post-infection and last ___.
* Vomiting more common in children than adults.
* ____ causes mild to moderate gastroenteritis, more prevalent in infants and toddlers
CALICIVIRIDAE
nausea, abdominal cramps, vomiting, watery diarrhea
- 1-2 days
- 1-3 days
- Sapovirus
- Maximum shedding occurs at symptom onset; can continue for 2- 3 weeks after symptoms resolve.
- Infection does not confer long-lasting immunity, complicating control of transmission
Viral Shedding
Diagnosis of CALICIVIRIDAE
* Culture in __
* __ is the most widely used identification method.
* Commercial __ kits available but have lower sensitivity and specificity than RT-PCR.
* Multiplex NAATs (e.g., ___ and ___) can detect Noroviruses and Sapoviruses from __ samples.
Human Intestinal Enteroids (HEI)
-RT-PCR
- ELISA
- Verigene Enteric Pathogens Test, FilmArray gastrointestinal pane
- stool
Enveloped, complex, pleomorphic rodlike shaped capsid, negative sense SSRNA
* __ and __ - classified as members of the
family ___ but are now classified as___
* Long threadlike viruses, hence the name (____) -
range in size from ____.
* Cause severe or fatal hemorrhagic fevers and are endemic in Africa
FILOVIRIDAE
- Marburg and Ebola viruses
- Rhabdoviridae
- Filoviruses (Filoviridae)
- filum means thread
- 80 to 800–1000 nm
MOT: Direct contact with bodily fluids, infected animals (__,__ and ___), fomites, sexual transmission
* Incubation period: __
* Fever, severe headache, muscle pain, weakness, gastrointestinal symptoms, hemorrhagic symptoms (bleeding from the eyes, ears, nose, and mouth, as well as internal bleeding) ultimately leading to multi-organ failure and death
FILOVIRIDAE
- fruit bats, monkeys, apes
- 2-21 days
- Named after the Ebola river
- 1979 Ebola re-emerged in __, with serial person-to-person spread
- Another epidemic occurred in ____, in __.
Ebola Virus
- Sudan
- Kikwit, Zaire 1995
Ebola virus Strains
Zaire ebolavirus
Sudan ebolavirus
Tai Forest ebolavirus
Bundibugyo ebolavirus:
Reston ebolavirus
The most lethal strain, responsible for the majority of
outbreaks, with a mortality rate ranging from 50% to 90%
Zaire ebolavirus:
: Associated with outbreaks in Sudan and Uganda,
with a mortality rate of about 40% to 60%
Sudan ebolavirus
: A rare strain with a lower mortality rate,
associated with a single case
Tai Forest ebolavirus
: Identified in Uganda, with a mortality rate of
approximately 25% to 50%.
Bundibugyo ebolavirus
: Primarily found in animals, particularly in the
Philippines, and is not known to cause disease in humans
Reston ebolavirus
Ebola Virus Pathogenesis
Filovirus Replication
Cytokine Storm
Tissue Damage
: immune cells such as monocytes,
macrophages, and dendritic cells
Filovirus Replication
production of high levels of proinflammatory
cytokines, similar to what occurs with superantigens
Cytokine Storm:
necrosis in the liver, spleen, lymph nodes, and
lungs
Tissue Damage:
- The virus was first identified in ___ during simultaneous outbreaks in__,__,____,___ and ___
- linked to laboratory workers exposed to infected ____
Marburg Virus
- 1967
- Marburg and Frankfurt, Germany, and in Belgrade, Serbia
- African green monkeys
Marburg Virus Strains
Marburg Virus (Marburg, Germany)
Ravn Virus
: The original strain,
associated with the first outbreaks.
Marburg Virus (Marburg, Germany)
: Identified in a 1987 outbreak in the Democratic
Republic of the Congo, it is closely related to the Marburg virus.
Ravn Virus
Diagnosis of FILOVIRIDAE
* __ A primary method for identifying the viruses.
* __ Available in some research settings.
* __: Conducted in BSL-4 laboratories.
* ____: Used to detect IgM and IgG antibodies
against the Ebola virus.
RT-PCR Testing:
Electron Microscopy
Cell Culture
Antigen-Capture ELISA
Treatment/Prevention of FILOVIRIDAE
* Supportive Care:__,___,__ ___
Fluid replacement therapy, kidney dialysis,
blood transfusions, favipiravir
Treatment/Prevention of FILOVIRIDAE
Monoclonal Antibodies: ___ aand __
Treatments like ZMapp and MIL 77 are
Utilizing blood or plasma from
recovered patients to provide immune support.
Convalescent Plasma Therapy:
Vaccines of FILOVIRIDAE: At least 15 Ebola vaccines are in development, with____ emerging as the first to complete Phase III clinical
trials, showing substantial protection against EVD.
rVSV-ZEBOV
Major genera : __,___ and ___
* ___is the only member of the rubivirus group; disease manifestation: __ and its means of
spread differ from those of the alphaviruses
* Spherical enveloped viruses with a diameter of ___
genome is single stranded RNA
* From ‘toga’, meaning the ___, and refers to the viral envelope
TOGAVIRIDAE
– Alphavirus, Rubivirus, and Arterivirus
- Rubella virus
-German measles
- 50–70 nm
- roman mantle or cloak
__ genus consists of about 32 viruses of
which at least 13 are known to infect humans.
✓All of them are mosquito borne
Alphavirus
___, which is not arthropod borne and
which causes rubella
Rubivirus
- No known ___ cause disease in humans
Arteriviruses
Alphavirus
A. Encephalitis viruses
1. Eastern equine encephalitis (EEE)
2. Western equine encephalitis (WEE)
3. Venezuelan equine encephalitis (VEE)
B. Viruses causing febrile illness
1. Chikungunya virus (CHIKV)
2. O’nyong-nyong virus (ONNV)
3. Semliki Forest virus
4. Sindbis virus
5. Ross river virus
- Three members: __,__ and ___ cause encephalitis in horses and humans
- Vectors:__ and __
- Reservoir: ____
- Vaccine: ___ have been developed for EEE
and WEE and a ___ for VEE
Alphavirus—Encephalitis viruses
- Eastern, Western and Venezuelan equine
encephalitis viruses
- Culex and Anopheles mosquitoes
- wild birds
- Formalinized vaccines
- live attenuated vaccine
- In ___, means ‘that which bends up’, and refers
to the posture assumed by patients suffering from severe joint pains - Incubation period is __ with an average of ____
- Vector is ___.
- No animal reservoir has been identified
Chikungunya Virus
- Swahili
-1–12 days
- 2–3 days
- Aedes aegypti
Confined to Africa, is closely related to the chikungunya virus antigenically and causes a similar disease.
* Transmitted by the anopheles species __ and ___
* ___causes a similar disease in the west India and South America
O’nyong-nyong Virus
- (Anopheles funestus and Anopheles gambiae)
- Mayaro virus
- Has not been associated with clinical illness in humans though neutralizing
antibodies to the virus have been demonstrated in Africans
Semliki Forest Virus
- Originally’ isolated from __ in the Sindbis district of
Egypt in 1952, has subsequently been recovered from other parts of Africa, India, Philippines and Australia. - In Africa, it is known to be associated with febrile illness in human beings
Sindbis Virus
- culex mosquitoes
- Has been associated with epidemic polyarthritis in Australia
Ross River Virus
“____”
* highly contagious virus that primarily affects humans and is transmitted through respiratory droplets when an infected person coughs or sneezes.
* can also be transmitted from mother to fetus during pregnancy
* Incubation period: ___
* Common symptoms include Mild fever, rash that starts on the face and spreads to the rest of the body, ___ (swollen lymph nodes), joint pain (more common in adults), cold-like symptoms (e.g., runny nose, sore throat)
Rubivirus—Rubella Virus
“German Measles”
- 14-21 days
- lymphadenopathy
Infection during the first trimester poses
significant risks to the developing fetus,
potentially leading to___
* CRS can result in serious birth defects,
including:
1
2
3
4
5
* The risk of it is highest when the
mother is infected during the first
trimester.
Rubivirus—Rubella Virus
- congenital rubella syndrome (CRS)
-* Heart defects (e.g., patent ductus
arteriosus)
* Hearing loss
* Cataracts
* Microcephaly
* Developmental delays
- Diagnosis is primarily based on clinical presentation, including characteristic rash and associated symptoms
- Serological tests can detect specific IgM and IgG antibodies against rubella virus.
- ____can be used to detect viral RNA in clinical specimens.
Rubivirus—Rubella Virus
-PCR (polymerase chain reaction) tests
Vaccination:
* The most effective way to prevent rubella and its complications is through vaccination.
* The ___ vaccine is commonly
administered in childhood, typically around __
with a booster dose given between ___
MMR (measles, mumps, rubella)
-12-15 months of age
- 4-6 years
