Foodborne viruses; Rotavirus - PowerPoint Presentation

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Foodborne viruses; RotavirusSlide2

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Global Impact of Gastroenteritis

www.who.int/vaccine_research/diseases/diarrhoeal/en/print.htmlSlide3

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FOODBORNE GASTROENTERITIS

www.cdc.gov/ncidod/dbmd/diseaseinfo/foodborneinfections_g.htm

Bacterial Agents

Campylobacter spp.

Salmonella spp.

E. coli STEC, ETEC, Other

Shigella spp.S. aureusC. perfringensC. botulinumL. monocytogenesV. choleraeV. parahemolyticusV. vulnificusVibrio spp.B. cereusY.enterocoliticaStrep spp., Grp ABrucella spp.

Viral Agents

Norovirus

Hepatitis A

Rotavirus

Sapovirus

Astrovirus

Other ???

Protozoan Agents

Giardia

intestinalis

Cryptosporidium

parvum

Cyclospora

cayatenensis

Toxoplasma

gondii

Trichinella

sppSlide4
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Rotavirus

;

VirologyFamily:

ReoviridaedsRNA, 11 segments, non-

enveloped

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serogroups

A-G; only A, B, C infect humansMany serotypes within serogroup Aresponsible for 90% of cases worldwide. However…Serotype prevalence varies geographicallyReassortments and antigenic drift occur5Slide6

Based on the

antigenicity

of VP7 and VP4, group

A rotaviruses have been serologically classified into

G serotypes

and P serotypes, respectively. Recently

, genotypes

of group A rotavirus, G type and P type defined by VP7 gene and VP4 gene, respectively, have been commonly utilized to characterize rotaviruses because these types generally represent the G and P serotypes [Estes and Kapikian, 2007].Slide7
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Rotavirus; an introduction

M

ost common cause of severe diarrhea among infants and young childrenNearly every child in the world has been infected with rotavirus at least once by the age of fiveImmunity develops with each infection, so subsequent infections are less severe; adults are rarely affectedSlide10
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Fact Sheet

http://

www.ncirs.edu.au/immunisation/fact-sheets/rotavirus-fact-sheet.pdfAlthough rotavirus was discovered in 1973 and accounts for up to 50% of hospitalisations for severe diarrhoea

in infants and children, its importance is still not widely known within the public health community, particularly in developing countries.In addition to its impact on human health, rotavirus also infects animals, and is a pathogen of livestock.Slide12

Rotavirus

An

estimated 527,000 children died in 2004; approximately 85% of those occurred in South Asia and sub-Saharan AfricaIn 2009, the World Health Organization (WHO) recommended inclusion of rotavirus vaccination in all national immunization programsSlide13
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Transmission

Children can spread the virus both before and after they become sick with diarrhea.

The virus spreads by the fecal-oral route; this means that the virus must be shed by an infected person and then enter a susceptible person’s mouth to cause infection.Rotavirus can be spread by contaminatedHandsObjects (toys, surfaces)

FoodWaterSlide16

Pathogenesis

Largely unknown

As many as 50% infections subclinicalIt infects and damages the cells that line the small intestine and causes gastroenteritis (which is often called "stomach flu" despite having no relation to influenza). Slide17

Rotavirus;

Epidemiology

Human reservoirTransmission: person-to-person fecal - oral; very rarely waterborne, foodbornerespiratory?Characteristics that facilitate spread

Virus shed in very large amounts; prolonged sheddingSmall infectious dose

Environmental

stabilitySlide18

Rotavirus:

Clinical Features

Incubation period----24-72 hDuration of illness---- 3 to 8dMost severe illness in

infants 6m – 2yrsFever, vomiting, diarrhea

Dehydration with severe electrolyte abnormalities

Exacerbating factors: malnutrition, immunodeficiency & poor sanitation

Decrease in illness severity with ageSlide19

Diagnosis

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.  Other methods, such as electron microscopy

 and PCRReverse transcription-polymerase chain reaction (RT-PCR) can detect and identify all species and serotypes of human rotavirusSlide20
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Prevention

Good hygiene (hand washing) and cleanliness

Vaccines are very effective. CDC recommends routine vaccination of infants with either of the two available vaccines:RotaTeq® (RV5), which is given in 3 doses at ages 2 months, 4 months, and 6 monthsRotarix® (RV1), which is given in 2 doses at ages 2 months and 4 months.

Very effective (85% to 98%) in preventing severe rotavirus disease in infants and young childrenSlide22

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Rotavirus;

Vaccines

RotaTeq

®

Pentavalent

vaccine containing G1, G2, G3, G4, P[8]

Licensed by FDA in 2006Rotarix®Monovalent contains genotype G1P[8]Relies on heterotypic immunityLicensed by FDA in 2008Widely used in BrazilSlide23
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Countries Using Rotavirus Vaccine in National Immunization Schedule

Source: WHO/IVB database, 193 WHO Member States. Data as of July 2009. 2009 data is provisional

Date of slide: September 2009

The boundaries and names shown and the designations used on this map do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement.

© WHO 2009. All rights reserved

No

(170 countries or 88% of countries)Yes (17 countries or 9% of countries)

Yes (Part of the country)

(2 countries or 1% of countries)

Introduction in 2009

(6 countries or 3% countries)

Yes (Risk groups)

(1 country or 0.5% of countries)

In 2008,Peru and South Africa had introduced in parts of the country and Colombia for risk groupsSlide26

A note

Vaccinated and unvaccinated children may develop rotavirus disease more than once because there are many different types of rotavirus and because neither vaccine nor natural infection provides full immunity (protection) from future infections. Usually a person’s first infection with rotavirus causes the most severe symptoms.