*Reoviridae: Respiratory Enteric Orphan viruses*
These viruses were initially found in respiratory and enteric tracts, but were not associated with specific illnesses. Be aware that they were formerly included in the Picornavirus family.
Orthoreovirus
Aka, mammalian reovirus, often referred to simply as Reovirus.
Double layers of capsid proteins.
Fecal-oral transmission.
Infects the
upper respiratory and gastrointestinal tracts.
Acid stable.
Infection is typically
asymptomatic; not a significant source of disease.
Causal relationship between Reovirus and the development of intolerance towards dietary antigens has been suggested.
For example, a causal relationship between Reovirus infection and development of
Celiac disease is of special interest.
Rotavirus
"Wheel-like" morphology.
Fecal-oral transmission.
Major cause of
severe diarrhea in young children and infants
In areas of malnutrition and dehydration, the diarrhea can lead to death.
Rotaviruses have
enterotoxin-like effects:
– NSP4 protein increases enterocyte cytoplasm calcium concentration, which leads to changes in the cytoskeleton.
– These changes disrupt membrane transport in ways that promote water and electrolyte loss (diarrhea).
Virus is shed in the feces, which promotes its transmission to new hosts.
Vaccine: Because the rotavirus can cause severe morbidity or even death, the rotavirus vaccine is recommended for all infants.
Coltivirus
Transmitted via
arthropods (wood ticks).
Virus replicates in the
bone marrow, where it infects
erythrocyte precursors, but doesn't kill them.
Instead, the coltivirus persists in the mature red blood cells, which allows it to
evade the immune system.
Colorado Tick Fever
Biphasic fever, headache, chills, muscle pain that is particularly prominent in the posterior legs, photophobia, and leukopenia.
Notice that these symptoms and the route of transmission are similar to
Lyme disease; thus, Lyme disease must be ruled out.
No specific antiviral treatment or prevention for Colorado Tick Fever.
