Reoviruses & RotavirusFadi Marroushi

UPJSMicrobiology

2015

ReoviridaeThe name Reoviridae is derived from respiratory

enteric orphan viruses. The term orphan virus means that it is not associated with any known disease. Even though viruses in the Reoviridae family have more recently been identified with various diseases, the original name is still used. A family of viruses that can affect the

gastrointestinal system and respiratory tract.

REOVIRIDAE of VERTEBRATES

ORTHOREOVIRUSES

ORBIVIRUSES

WorldwideOral/fecalMammalian reovirusestypes 1, 2, 3

Humans, cattle, sheep, swine

Gastroenteritis, respiratory disease

Wide range of symptoms from inapparent to lethal

Asia, Americas

ROTAVIRUSES

Groups D, E, F Mammals, birds Oral/fecal

Table 3.13

Fusogenic

Non-fusogenic

GENUS/ MEMBERS

USUAL HOST(S)

TRANSMISSION or VECTOR

DISEASE WORLD DISTRIBUTION

VIRUS NAMEABBREV.

MRV

Nelson Bay virus Flying foxes (bats) AustraliaNBV

Avian reoviruses5 serotypes

Birds Oral/fecal WorldwideARV

Equines Culicoides Cardiopulmonary disease

AfricaAfrican horse sickness10 serotypes

AHSV

Sheep, cattleBluetongue24 serotypes

Culicoides Africa, Australia,Rhinitis, stomatitisBTV

Changuinola Phlebotamines Fever PanamaHumansCGLV

COLTIVIRUSES

Colorado tick fever Humans Ticks Fever, encephalitis North AmericaCTFV

Group A Humans, animals Infant diarrhea WorldwideOral/fecalRV-A

Group B Humans, animals Epidemic adult diarrhea

Primarily ChinaOral/fecalRV-B

Group C Humans, animals Clinical significance unknown

Oral/fecalRV-C

Reptilian reoviruses Snakes? ?

Baboon reovirus Monkeys Oral/fecalBRV ?

Kemerovo serogroup:

Ticks Fever, encephalitis

E. Europe, United States

Wad Medani

Great Island Chenuda Seabirds

Domestic animals

Kemerovo Humans?GIV

CNUVWMV

FishAQUAREOVIRUSES

five serogroups ? ? ?

SEADORNAVIRUSES

Eyach EYA Humans Ticks EuropeFever, encephalitis

Banna BAVKadipiro KDV

Humans Mosquitos(Culex sp.)

Fever, encephalitis Southeast Asia. Indonesia, China

RotavirusRotavirus is a virus that infects the intestinal

tract of almost all young children by age 5. Children can get rotavirus more than once, but the first infection is usually the worst. This infection causes stomach upset and diarrhea.

Causes severe gastroenteritis.The most common cause of severe diarrhea

among infants and children.Causes death of about 500,000 children

worldwide every year.

History1973: the virus was identified by Ruth Bishop and

collagues.

1974: Named by Thomas Henry Flewett.

1980: Rotavirus serotypes were first described.

1981: Rotavirus from humans was first grown in cell cultures derived from monkey kidneys, by adding trypsin to the culture medium.

Classification & IdentificationFamily ReoviridaeSubfamily SedoreovirinaeGenus RotavirusGroup III double stranded RNASpecies Rotavirus A, B, C (human)

• Serological Test• Rotavirus detection kit• Feces tests

StructureLinear Double-stranded RNA genome housed

within an icosahedral capsid.Non-enveloped.The outer capsid has T=13 icosahedral symmetry.The inner capsid has T=2 icosahedral symmetry.Consists of 10 to 12 segments.The 5th terminus of the segments have a

methylated nucleotide cap.

ReplicationReplication begins by attachment to host receptors and endocytosis into host cell vesicles.  Particles are then partially uncoated in endolysosomes, and penetrate into the cytoplasm.  Replication of the Reoviruses occurs by early transcription of each segment of the dsRNA genome by viral polymerase inside the sub-viral particle resulting in full-length plus-strand transcripts from the [-] strand template.  These +sense RNA molecules are then translated into the various viral proteins.  Some of the [+] RNAs are then encapsulated in a sub-viral particle, and are transcribed to give [-] RNA molecules.  The [-] RNAs remain base-paired with the [+] RNAs, giving rise to the dsRNA viral segments of the genome. The capsid is then assembled on the sub-viral particle to form the mature virion.

Causes & Incubation periodRotavirus spreads easilyOften spreads where many children are together.Spreads through contact with stool from an

infected child.Children who get the rotavirus germs on their

hands can get the infection when they put their hands in their mouths. They can also get infected with rotavirus by chewing on a toy that has the germs on it.

Incubation period is typically around two days.

SymptomsFeverVomitingWatery diarrheaAbdominal painDehydration (dry mouth, crying without tears,

little or no urination)Sometimes bloody diarrhea

TreatmentThere's no specific treatment for a rotavirus

infection.Antibiotics won't help a rotavirus infection.Usually, the infection resolves within three to

eight days.Preventing dehydration is the biggest concern.

VaccineTwo rotavirus vaccines, RotaTeq and Rotarix.

both are given orally and do not require an injection,

these vaccines are most effective if the first dose isgiven before age 15 weeks.

RotaTeq (RV5): is given on a schedule of three doses at ages 2 months, 4 months, and 6 months.

Rotarix (RV1) is given on a schedule of two doses at ages 2 months and 4 months.

Referenceshttp://www.viprbrc.org/brc/aboutPathogen.spg?de

corator=reo#VIhttp://emedicine.medscape.com/article/227348-ov

erviewhttps://microbewiki.kenyon.edu/index.php/Reoviri

daehttp://www.medicinenet.com/rotavirus/article.htm

#rotavirus_infection_factshttp://

www.webmd.com/children/vaccines/tc/rotavirus-topic-overview