Paramyxovirus lec

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1 Paramyxo viruses

Transcript of Paramyxovirus lec

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Paramyxo viruses

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Paramyxo viruses

• Paramyxoviruses are enveloped RNA virus.

• Contain one piece single stranded RNA.

• Surface spikes are: hemagglutinin, nuraminidase and fusion protein.

• Paramyxo viruses are:

Measles virus

Mumps virus

Respiratory syncytial virus

Parainfluenza virus

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Paramyxo viruses

Virus Hemagglutinin Nuraminidase Fusion protein

Measles + - +

Mumps + + +

Respiratory syncytial

- - +

Parainfluenza + + +

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Paramyxoviridae structure

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Measles virus

Measles virus

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Measles virus

• Reservoir

– Humans

• Transmission

– Person-to-person via droplets during

prodormal period and a few days after

symptos.

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Measles virus

• Incubation period

– Average 10-14 days.

• Infectious period

– From 4 days prior to rash onset to 4 days

after rash onset.

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Measles pathogenesis

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Clinical features

• Prodrome:

• Fever,

• cough,

• coryza,

• conjunctivitis.

Koplik’s spots - Bright red lesion with a white central dot, located on the buccal mucosa.

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Clinical features

• Rash: maculopapular,

begins at hairline, progresses downward

• Complications– Diarrhea, – Otitis media– Pneumonia, – Encephalitis

• Measles in pregnancy cause stillbirth rather than congenital anomalies.

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Laboratory diagnosis

• Typical clinical presentation.

• Laboratory confirmation:

• Isolation of measles virus

• Significant rise in measles IgG by any

standard serologic assay

• Positive serologic test for measles IgM

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Control measures

• Prevented by immunization with a live

attenuated vaccine.

• Should be administered with mumps and

rubella as MMR, or with mumps, rubella

and varicella as MMRV

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Mumps virus

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Transmission

• Reservoir: Human

• Transmission: Respiratory droplet nuclei.

• Incubation period: 18-21 days.

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Mumps Pathogenesis

• Respiratory transmission of virus

• Replication in nasopharynx and regional

lymph nodes

• Viremia with spread to tissues

• Multiple tissues (parotid glands, testes,

ovaries, pancreas) infected during viremia

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Clinical conditions

• Prodromal symptoms: Fever, myalgia, malaise, headache.

• Followed by acute onset of cute onset of unilateral oror bilateral tender, self-limited self-limited swelling of the of the

parotid gland (s).

• Complications:

Orchitis, Ophoritisphoritis

Sterility, Pancreatitis

CNS involvement

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Laboratory Diagnosis

• Isolation of mumps virus in cell culture.

• Detection of mumps IgM antibody

• Detection of mumps IgM antibody

• A four-fold rise in IgG antibody

• Detection of mumps DNA by PCR,

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Mumps Vaccine

• Prevented by live, attenuated vaccine.

• Should be administered with measles and

rubella (MMR) or with measles, rubella and

varicella (MMRV)

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Respiratory Syncytial Virus (RSV)

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Resp. Sync. Virus

• Enveloped, single stranded, RNA virus.

• Host range limited to humans; single

serotype

• Transmission via droplets, fingers, fomites

• Incubation period- 2-8 days

• Entry through mucosa of nose and eye

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Clinical Features

• Upper respiratory infection in older

children and adults:

Fever, Rhinitis, Pharyngitis & otitis media

• Lower Respiratory Infection in infants:

Bronchiolitis, Pneumonia, Cough, Poor

feeding, lethargy, Hypoxemia, Respiratory

Distress, Apnea

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22RSV Bronchiolitis- clinical features

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Parainfluenza viruses

• Enveloped, single stranded, RNA virus.

• Four serotypes, host range limited to

humans,

• Transmission via respiratory droplet.

• Infections limited to respiratory tract,

generally non-systemic and viremia rare.

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Parainfluenza viruses

• Serotypes 1 and 2 cause cold-like symptoms,

bronchitis and croup.

• Serotypes 3 causes infection of children in lower

respiratory tract.

• Diagnosis

– Virus culture

– Syncytia formation

– A 4 foled rise of antibody titer.

– PCR

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