Family Corona Toga/Flavi Picorna Calici RetroGenome <-------------------------------------------ss (+) RNA---------------------------------------------> Diploid (+) RNA

Capsid symmetry Helical <--------------------------------------Icosahedral------------------------------------------------->

Envelope <----------------------Yes--------------------> <---------------------No----------------------> Yese.g. Human corona

virusRubella virusHepatitis C virus

PolioHepatitis A virus

Norwalk agentHepatitis E virus

HIV-1

Plus Sense RNA Viruses

Famiglia CoronaviridaeVirus rotondeggianti di 80-160 nm di diamFormati da:

rivestimento esterno glicoproteico formato da unitàtozze e ben visibili (aspetto a corona)capside interno elicoidale e flessibile di 20nm di diamun genoma: RNA monocatenario non segmentato (+) infettante di 27-31.000 paia di basi

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Coronaviridae

Schema grafico Immagine reale

The envelope carries three glycoproteins:S - Spike protein: receptor binding, cell fusion, major antigenE - Envelope protein: small, envelope-associatedproteinM - Membrane protein: transmembrane - budding& envelope formation In a few types, there is a third glycoprotein:HE - Haemagglutinin-esteraseThe genome is associated with a basic phosphoprotein, N.

ReplicazioneEntrano per endocitosiRestano nel citoplasmaLa progenie si assembla nel

GolgiEscono per gemmazioneCrescono lentamente (24-

48 ore)

Famiglia Coronaviridae

Due Generi che infettano i vertebrati:CoronavirusTorovirus

Le infezioni umane da Coronavirus

Coronavirus:tre gruppiGruppo I HCoV-229E

diarrea epidemica del maiale gastroenterite trasmissibile del maiale gastroenterite del cane peritonite infettiva del gatto

Gruppo II HCoV-OC43epatite del topo

virus boviniGruppo III Virus della

bronchite aviaria (CoV) T CoV (tacchino)

These viruses infect a variety of mammals& birds. The exact number of humanisolates are not known as many cannot begrown in culture. In humans, they cause: Respiratory infections (common), includingSevere Acute Respiratory Syndrome(SARS) Enteric infections (occasional - mostly in infants <12 months) Neurological syndromes (rare)

TRASMISSIONE

by aerosols of respiratory secretionsby the faecal-oral route by mechanical transmission.

EpidemiologiaCoronavirus infection is very common and occurs

worldwide.The incidence of infection is strongly seasonal, with

the greatest incidence in children in winter. Adult infections are less common.The number of coronavirus serotypes and the extent

of antigenic variation is unknown. Re-infections appear to occur throughout life,

implying multiple serotypes (at least four are known) and/or antigenic variation, hence the prospects for immunization appear bleak.

PatogenicitàMost virus growth occurs in epithelial cells. Occasionally the liver, kidneys, heart or eyes may be infected,

as well as other cell types such as macrophages.

In cold-type respiratory infections, growth appears to belocalized to the epithelium of the upper respiratory tract, butthere is no adequate animal model for the human respiratorycoronaviruses.

Clinically, most infections cause a mild, self-limited disease(classical 'cold' or upset stomach), but there may be rare neurological complications. SARS is a form of viralpneumonia where infection encompasses the lowerrespiratory tract.

SARSSARS is a type of viral pneumonia, with symptoms including

fever, a dry cough, dyspnea, headache, and hypoxaemia(low blood oxygen concentration).

Typical laboratory findings include lymphopaenia (reducedlymphocyte numbers) and mildly elevatedaminotransferase levels (indicating liver damage).

Death may result from progressive respiratory failure due toalveolar damage.

The estimated case fatality rate is 13·2% for patients youngerthan 60 years and 43·3% for patients aged 60 years or older

DIAGNOSI DI LABORATORIO

Serological testing for anti-coronavirus antibodies consists of indirect fluorescent antibody testing and enzyme-linkedimmunosorbent assays (ELISA)

Although some patients have detectable coronavirus antibody within 14 days of illness onset, definitive interpretation of negative coronavirus antibody tests is possible only forspecimens obtained >21 days after onset of fever.

Molecular testing consists of reverse transcriptase-polymerase chain reaction (RT-PCR) tests specific for the RNA

This can detect infection within the first 10 days after the onset of fever in some SARS patients, but the duration of detectable viraemia and virus shedding is unknown, so RT-PCR tests performed too late could give negative results.