myxovirus and rubella

INFLUENZA VIRUS-DR.AKIF A.B

INFLUENZA VIRUS-Segmented RNA virus

- Helical symmetry

-Types :

1) Influenza A : MC cause of epidemics

- only cause of Pandemic

2) Influenza B

3) Influenza C : Not circulating currently

ANTIGENS OF INFLUENZA1) Haemagglutinin : Causes haemagglutination

2) Neuraminidase : Causes reversal of haemagglutination k/a Elution

Currently CirculatingINFLUENZA VIRUSES1) H1N1 = Swine Flu

2) H2N2

3) H3N2 =Seasonal flu

4) H5N1 = Bird Flu

5) H7N9

6) H5N6

7) TYPE - B

TYPE A

ANTIGENIC VARIATIONSANTIGENIC SHIFT ANTIGENIC DRIFT

Due to genetic Reassortment Due to point mutation

Occur in Type A Type A as well as in Type B

Pandemic and epidemics sporadic cases

Sudden onset Gradual onset

AVIAN INFLUENZA -Caused by H5N1 (MC Type)

H7N7 (Netherlands)

H9N2 (Hong Kong)

H7N9

-Bird Flu

-DOC : Oseltamavir 75mg bd for 5 days (C.I in Infants)

CLINICAL FEATURES-Incubation Period = 18-72hrs

-MC Presentation : Flu like symptoms

-MC complication : Bacterial Pneumonia (S.aureus> Pneumococci)

-Reye Syndrome : Common with Type B Influenza following Aspirin intake.

DIAGNOSIS-Most sensitive test = ELISA

-Most specific test = Neutralisation Test

VACCINES-Killed Vaccine

: 2doses, I.M route, 70-90% efficacy, last for 6-12months

-Life nasal Spray vaccine(Trivalent vaccine)

1) Influenza A (H1N1)

2) Influenza A (H3N2)

3) Influenza B

Influenza vaccine can lead to Guillian Barre Syndrome

SWINE FLU (H1N1)-Originated by genetic reassortment of four strains : 1 human

2 swine 1 avian

-Uncomplicated case presents with flu like symptoms (URTI)

-Complicated cases presents with pneumonia, dehydration, CNS involvement and multi-organ failure

SWINE FLU (H1N1)Risk factors for severe Disease

1) Infants and children <2yrs

2) Persons aged >65yrs

3) Pregnant females

4) COPD

5) Immunosuppressive diseases

6) Chronic cardiac disease

SWINE FLU (H1N1)DIAGNOSIS

1) RT-PCR : Most sensitive

2) Samples : Nasopharyngeal or throat swabs

-Patient to be isolated for 7days.

SWINE FLU (H1N1)TREATMENT

1) Oseltamavir 75mg bd for 5 days

2) Zanamavir 2 inhalations bd for 5 days

Prophylaxis : Oseltamavir 75mg once a day, duration depends on clinical settings.

PARAMYXOVIRUS- DR.AKIF A.B

PARA-INFLUENZAVIRUSES

-MC agent of Croup ( Acute Laryngo-Tracheo bronchitis)

-MC complication : Otitis media

EPIGLOTITIS

THUMB SIGN

Steeple sign

CROUP

MUMPS VIRUS-MC cause of Parotid Gland enlargement in children

-MC manifestation = Bilateral parotiris > Epididymo orchitis

-MC complication : Aseptic meningitis

-MC Complication in adolescent : Orchitis, Oopheritis

-Atypical Mumps : Patient directly presents with Aseptic Meningitis and parotitis is absent

-Once infected gets life long immunity

-Period of communicability : 4-5 days before to 7days after onset of symptoms.

- Vaccine : Live vaccine, Jeryll Lynn Strain

RUBELLA-Caused by Togavirus

-Also known as German Measles

-Incubation period = 14days

-Vaccine = RA 27/3 strain , Live vaccine, Subcutaneous

-Rubella vaccine is C.I in Pregnancy and if female is vaccinated she should be advised to prevent pregnancy for next 3 months

-Priority for vaccination:

1) 15-49 yrs reproductive age females

2) 1-14yrs children

CONGENITAL RUBELLASYNDROME

Infection in 1st trimester

Heart Disease (MC: PDA ) +Eye defect(MC: Salt and Pepper Retinopathy>Cataract)+Sensorineural deafness (MC)

- Blue berry muffin lesions

Infection in early part of 2nd trimester :

Only deafness

Infection after 16th week :

No abnormalities.

BLUE BERRY MUFFIN LESIONSRubella

Toxoplasmosis

Cytomegalovirus

Herpes simplex

Coxsackie virus

Parvovirus

Epstein Barr virus

Syphilis

Salt and Pepper Retinopathy

-Seen in

1) Syphilis

2) Rubella

3) NARP Syndrome

MEASLES-Rubeola

-Incubation period : 10-14 days

-No carriers

-Secondary attack rates : 80%

-MC complication : Otitis Media

-Koplik spots are present opposite 2nd upper molar

-Rarest but severe complication : Subacute Sclerosing Panencephalitis

-Cytopathic effect : Multinucleated Giant cells( Warthin Finkeldey cells) Containing both intra cytoplasmic and intranuclear inclusion bodies.

Fever + 3 C’sC- Coryza C- Cough C- Conjunctivitis

Warthin Finkeldey cells

MEASLESIncubation period (10days)

Fever(10days)

Koplik’s spots(12th day)

Rash( 14th day )

MEASLES

MEASLES VACCINES-Edmonston Zagreb strain

-Lyophilised form

-Reconstituted with distilled water

-Live vaccine, Sub cutaneous

-Given at 9months since that time maternal antibodies disappears by that time.

-Side effects : Toxic shock syndrome

-Measles immunoglobulin or vaccine can be given after exposure within 72days but should not be given together.

MEASLES ERADICATION1) Catch up : one time effort to vaccinate all children from 9months-10years

2) Keep up

3) Follow up : done every 2-yrs following catch up campaigns to vaccinate children of age >9months who were born after catch-up campaign

RESPIRATORY SYNCYTIALVIRUS

-MC cause of LRTI in Infants causing Bronchiolitis, Pneumonia and tracheobronchitis.

-Diagnosis :HeLa and Hep-2 are most sensitive cell lines used

- Treatment : Ribavirin

EXANTHEMATOUS DISEASES

Very Varicella Rash appears 1 day after fever

Sick Scarlet fever 2days

Patients Pox (smallpox0 3 days

Must Measles 4days

Take Typhus 5days

No no No

Double Diphtheria 7days

Treatment Typhoid 7days

Patient is infective from 24hrs prior to onset of fever.