DR.T.V.RAO MD 1

ROTAVIRAL INFECTIONAN UPDATE

Dr.T.V.Rao MD

DR.T.V.RAO MD 2

IMPORTANCE OF ROTAVIRUSES• Rotaviruses are major cause of diarrheal illness in Human

infants in the world

• Adults too can get infected

• Young animals, calves, piglets can also infected

• Rotavirus infections spread easily. Outbreaks usually occur in the winter and early spring, between about November and April. Rotavirus infections often spread in settings where many children are together, such as daycare centres.

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GLOBAL IMPACT OF ROTAVIRUS INFECTIONS

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CHARACTERS OF ROTAVIRUS• A rotavirus has a characteristic

wheel-like appearance when viewed by electron microscopy (the name rotavirus is derived from the Latin rota, meaning "wheel"). Rotaviruses are non enveloped, double-shelled viruses. The genome is composed of 11 segments of double-stranded RNA, which code for six structural and five non-structural proteins. The virus is stable in the environment

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ROTAVIRUS RESEMBLES A WHEEL( ROTA = WHEEL )

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CLASSIFICATION OF ROTAVIRUSES

• Rota viruses are classified as Five species ( A- E )

• Two other species are tentatively identified

( F and G )

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STRUCTURAL CONFIGURATION OF ROTAVIRUS

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STRUCTURE OF ROTAVIRUSES• Antigenic classification

mainly dependent on structural protein VP6

• Group A is important human pathogen

• Outer capsid protein VP4 and VP7 carry epitopes important in neutralizing antibodies

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• Rota viruses are classified as Five species ( A- E )

• Two other species are tentatively identified

( F and G )

CLASSIFICATION OF ROTAVIRUSES

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TRANSMISSION OF ROTAVIRUS

• Rotavirus is transmitted by the faecal-oral route, via contact with contaminated hands, surfaces and objects, and possibly by the respiratory route. The faeces of an infected person can contain more than 10 trillion infectious particles per gram; fewer than 100 of these are required to transmit infection to another person.

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PATHOGENICITY• The virus infect the villi of the small intestine (Gastric and

colonic mucosa are not infected) • They multiply in the cytoplasm of the enterocytes and

damage their transport mechanisms.• The Rota viral encoded particle NSP4 is a viral enterotoxin

and induces secretions by triggering a signal transduction pathway

• Damaged cell may show into lumen of the intestinal and release large quantities of virus which appear in the stool.

• Viral excretion usually lasts for 2 – 12 days in otherwise healthy patients

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WHY DIARRHEA IN ROTA VIRAL INFECTIONS

• Diarrhea caused by Rotaviruses may be due to impaired sodium and glucose absorption as damaged cell on villi are replaced by non absorbing immature crypt cell

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IMMUNITY IN ROTA VIRAL INFECTIONS• By age 3 years, 90% of the

children have serum antibodies to one or more types

• Young children suffer upto to five reinfections by 2 years of age

• Secretary IgA or Interferon are important in protection against Rota viral infections.

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ROTA VIRAL INFECTION DAMAGES INTESTINES

• Pathogens, e.g., rotavirus, may strip the tips of the villi from large patches of the intestinal wall thus decreasing the surface area and decreasing by more than 50% the specific absorptive capacities of the intestine. The result is malabsorption which can cause malnutrition - most especially in a child already nutritionally compromised by repeated previous attacks of diarrhea.

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DEHYDRATION IS LEADING CAUSE IN MORBIDITY AND MORTALITY

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ROTA VIRAL INFECTION IN IMMUNOSUPPRESSED AND OTHERS

• In children with immunodeficienes , Rotavirus cause severe and prolonged disease.

• Adults seroconvert but not manfiest with diarrhea

• However in closed wards sever disease can occur.

• In India and China large outbreaks of severe gastroenteritis have occurred

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DIAGNOSIS OF ROTAVIRUS INFECTIONS

• Diagnosis of infection with rotavirus normally follows diagnosis of gastroenteritis as the cause of severe diarrhoea. Most children admitted to hospital with gastroenteritis are tested for rotavirus A. Specific diagnosis of infection with rotavirus A is made by finding the virus in the child’s stool by enzyme immunoassay. There are several licensed test kits on the market which are sensitive, specific and detect all serotypes of

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LABORATORY DIAGNOSIS• Microscopy ( EM )

Demonstration of Virus in stool helps in early disease

Electron Microscopy has made the identification simpler

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OTHER METHODS IN DIAGNOSIS

• Virus can be demonstrated by IEM

• Latex agglutination tests

• ELISA can detect antibodies and establishing raise in titers

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TREATMENT• Treatment of Gastroenteritis is supportive• Correction of Loss of water and electrolytes• Failure for prompt correction of dehydration leads to

Acidosis

Shock

Death

Correction Electrolyte remain the goal treatment in Rota viral infections.

Lesser deaths if effective replacement therapy is initiated

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UNICEF/WHO O.R.S

• Sodium Chloride 3.5 grams

• Sodium Bicarbonate 2.5 grams

• Potassium Chloride 1.5 grams

• Glucose 20 grams

• To be dissolved in one liter of clean drinking water

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• Management consists of replacement of fluids ( ORS ) and restoration of Electrolyte balance

• Oral rehydration Therapy is highly effective in reducing morbidity and mortality

• Severe dehydration needs parental administration of fluids.

FLUID REPLACEMENT

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BASIC MEASURES IN ROTA VIRAL PREVENTION

• Keep your hands clean. Wash hands often with soap and warm water after using the toilet, diapering and before preparing or eating food.

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EPIDEMIOLOGY• Rota viral infections continue to be most

important cause of Gastroenteritis in young children

• Estimates range 3 billion – 5 billion infections• Children > 5 years age highly susceptible to

infections• Results in 1 million deaths

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• Upto 50 % of cases of Acute Gastroenteritis of the Hospitalized children through the world are caused by Rotavirus

• Winter season highly predisposing

• Nosocomial infections need attention

IMPACT ON HOSPITALS

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PREVENTION AND CONTROL

• In view of fecal oral route of transmission waste water management, safe water supplies sanitation are significant control measurers.• Vaccine – In 2006 an Oral Bovine

based Rota viral vaccine was licensed in USA

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UPDATE ON VACCINATION• Two different rotavirus vaccines are currently

licensed for use in infants in the United States. The vaccines are RotaTeq® (RV5) and Rotarix® (RV1). Before being licensed, both vaccines were tested in clinical trials and shown to be safe and effective. In these studies, during approximately the first year of an infant’s life, rotavirus vaccine was found to prevent almost all (85%-98%) rotavirus illness episodes that were severe and to prevent 74%-87% of all rotavirus illness episodes.

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BASIC MEASURES IN ROTA VIRAL PREVENTION

• Keep your hands clean. Wash hands often with soap and warm water after using the toilet, diapering and before preparing or eating food.

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