Prevalence of Norovirus Among Citizens of the United States from 2006-2007

Maria Ayzza BarcarseMichael JohnsonElman Punzalan Michael Rosete

Extent of the problem

• Leading Cause of gastroenteritis & foodborne outbreaks in the United Stateso Accounts for 19-21 million reported cases of acute

gastroenteritis each year

• Very Contagious

• No vaccination or antiviral medications available

Centers for Disease Control and Prevention (CDC), 2013

Extent of the problem

• Morbidityo 1.7-1.9 million annual outpatient visitso 400,000 annual emergency department visitso 56,000-71 annual hospitalizations

• Mortalityo 570-800 deaths, mostly in young children and elderly

CDC, 2013

Agent of Disease

• Non-enveloped, single-stranded RNA virus

• Strains that infect humans - GI, GII, GIV

• GII. 4 strain is responsible for causing majority of gastroenteritis outbreaks worldwideo Minerva Strain (GII. 4, 2006) strain was the viral

strain involved in 2006-2007 US epidemic (CDC, 2007) CDC, 2007; CDC, 2013

The Norovirus Condition

• Gastroenteritis: Inflammation of the stomach and intestinal tracto Commonly referred to as stomach flu or food

poisoning

CDC, 2013

The Norovirus Condition

• Symptoms include:o Nauseao Aches (headaches, abdominal cramps)o Vomitingo Low-grade fevero Diarrhea

dehydrationCDC, 2013

The Norovirus Condition

• Symptoms appear 1-2 days after exposure

• Full recovery between 1-3 days

• Severe cases require hospitalizationo Typically occurs in the elderly (+65 Y/O)

• Diagnosis is made from symptoms of vomiting & diarrhea

California Department of Public Health, 2013

Modes of Transmission

• Direct contacto Fecal-oral routeo Physical contacto Linen or clothing items soiled with feces or vomito Contaminated services

CDC, 2013

Modes of Transmission

• Airborne droplet transmissiono Vomiting

CDC, 2013

Modes of Transmission

• Indirect contacto Contaminated watero Food contamination

Improper handling of food (ex: shellfish) Failure to wash hands

California Department of Public Health, 2013; CDC, 2013

Mechanisms to control the problem or spread of disease

• Routine hand washing

• Proper food handling practices

• wash & cook food thoroughlyo Clean surfaceso Cleaning soiled

laundry immediatelyCDC, 2013

Host Factors of Vulnerability

• Due to the virulent nature, all people are affectedo However, some may be at greater risk than others

• Raceo A single study of military personnel has suggested

African Americans may have a protective factor.

Host Factors of Vulnerability• Gender, Marital Status

o There is no evidence to suggest disparities based on gender or marital status, however married couples may have a higher risk for transmission due to close proximity.

● Age○ Young children and elderly are at

higher risk for prolonged symptoms

■ These populations are at higher risk for dehydration and must quickly replenish water.

Environmental & Occupational Risks

• Prevalent in Enclosed Areaso Including nursing homes, cruise ships, hospitals

• Higher Risk for Those:o Working in food service, hotels or cruise shipso Working for institutional facilities such as schools,

prisons, hospitals

(Ecolab, 2013)

Geographic Risk

• Tends to be more prevalent in colder climates and colder weathero Far north or south

climates may be at greater risk

Reynolds, et al, 2002; CDC, 2013

Geographic Risk

• Geographic Study in Japano Found over the course of three years that the

Northern regions of Japan see a spike of norovirus cases as temperature and humidity rapidly drops in the Fall/Winter months.

Suzuki, Saito, Matsuno, Shobugawa, 2013

Geographic Study in Japan

Seino, n.d.

Temporal Variation

• Cyclical Trendso Cases typically increase in the colder winter months

of the year and decrease in warmer months

Temporal Variation

• Norovirus is an Endemico It is transmitted in all parts of the world and in the

United States, occurs relatively frequently.

• Epidemicso However, with major outbreaks such as 2006-2007’s

outbreak, can become an Epidemic. This is due to it’s tendency to spread rapidly and

affect large amounts of people.

(Media Office at the UNSW Australia, 2013)

Epidemiologic Variables

● First identified in 1972 after a gastroenteritis outbreak occurred in Norwalk, Ohio.

● Outbreaks have been traced back to companies who handle food.○ Agricultural workers○ Food suppliers/distributors○ Restaurant workers

California Department of Public Health, 2013

Hypotheses• Lack of adherence to food handling guidelines

• Lack of proper sanitation and disinfection of contaminated surfaces

• More time spent indoors during winter months

Norovirus 2006-2007

• When new strains of diseases are introduced, outbreaks often occur.o This occurred in the winter of 2006, continuing into

2007 with the “minerva” strain of Norovirus

CDC, 2013

Norovirus 2006-2007

Norovirus Associated Deaths

CDC, 2013

Norovirus 2006-2007Norovirus Associated Hospitalizations

CDC, 2013

Norovirus 2006-2007Norovirus Associated Emergency Department Visits

CDC, 2013

Norovirus 2006-2007

Norovirus Associated Outpatient Visits

CDC, 2013

Gaps in knowledge

● A researcher’s point of view, limited knowledge about the norovirus○ Biological Data○ Genetic Diversity

CDC, 2013

Gaps in knowledge

● The public's point of view, insufficient knowledge about the disease

● A person can become infected with the norovirus multiple times throughout their lifetime.

● Currently there is no treatment for it.

CDC, 2013

Existing/Proposal Policies● Suspected Norovirus Outbreak

○ State, local, and territorial health departments■ serve as the lead agencies■ interview patients and perform diagnostic testing

○ Food regulatory agencies (FDA, USDA, and State authorities).

○ CDC investigations and control. ○ Kaplan Criteria

CDC, 2013

Existing/Proposed Policies

● Policies in a Healthcare Setting○ Protocol

■ Notification of infected persons, including patients and staff members, to the proper authorities

■ Ward closures and isolation of infected persons from other patients

■ Aseptic technique with regards to hand washing and proper use of personal protective equipment when involved

with a patient care.

CDC, 2013

Significance of health policies

● These health policies can help:○ Prevention○ Containment○ Treatment

Areas for Further Epidemiologic Research● Identify emerging strains which are

pathogenic.● Better understanding of the body’s response

to various strains.○ To determine the likelihood of a person to serve as a

reservoir for transmission.■ Identifying predisposing factors that increase

susceptibility.National Institute of Allergy and Infectious Diseases, 2013

Areas for Further Epidemiologic Research● Vaccine development

○ Identify individuals/groups most often infected to determine for whom the vaccine is of utmost priority.■ High-risk groups:

● Young children● Elderly

■ Special interest groups:● Healthcare workers● Travelers● Military personnel

National Institute of Allergy and Infectious Diseases, 2013

Conclusion● Norovirus is very contagious!

○ Direct vs. Indirect transmission○ Cleanliness and hand hygiene very helpful

● Special concern for certain age groups● Not a quick fix

○ No available vaccine or antiviral medication○ Caused by a virus

Class Activity

Question 1

Based upon our research, what factor does NOT contribute to the spread of norovirus.

A. Climate and Weather

B. Food Handling Practice

C. Sedentary Lifestyles

D. Disinfection of Surfaces

Question 2

Which Strain of Norovirus was prevalent in the 2006-2007 epidemic?

A. The Bermuda Strain

B. The Kreuzen-Johnson Strain

C. The Minerva Strain

D. The Yosemite-Islet Strain

Question 3

What groups of people are NOT considered to be at high risk for contracting norovirus.

A. Elderly

B. Institutional Workers

C. Young Children

D. College Students

Question 4What is the significance of the geographic study in Japan?

A. Helped to reinforce that colder climates have higher rates of norovirus

B. Helped to establish that Asian races are at higher risk for contracting norovirus

C. A & B

D. None of the above

Bonus Question

The Norovirus is the leading cause of gastroenteritis outbreaks in the United States. How many cases are reported each year?

ReferencesCalifornia Department of Public Health. (2013). Norovirus (Norwalk Virus). Retried October 5, 2013, from

http://www.cdph.ca.gov/HealthInfo/discond/Pages/Norovirus.aspx

Centers for Disease Control and Prevention (CDC). (2007). Norovirus activity - United States, 2006-2007. Retrieved from, http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5633a2.htm

Centers for Disease Control and Prevention (CDC). (2013). Surveillance for Norovirus Outbreaks. Retrieved from, http://www.cdc.gov/features/dsnorovirus

Centers for Disease Control and Prevention (CDC). (2013). Trends of Norovirus-associated outcome figures. Retrieved November 19, 2013, from http://www.cdc.gov/norovirus/trends-outbreaks-figure-1.html

Ecolab Inc. (n.d.) Norovirus. Retrieved October 2, 2013, from http://www.ecolab.com/our-story/our-company/our-vision/safe-food/microbial-risks/norovirus

Reynolds, R.W., N.A. Rayner, T.M. Smith, D.C. Stokes, and W. Wang (2002). "An improved in situ and satellite SST analysis for climate". J. Climate 15: 1609-1625

Seino, H. (n.d.) Annual mean temperature graph. Retrieved November 17, 2013 from, from http://www.niaes.affrc.go.jp/topics/g7/tm.gif

Suzuki, H., Saito, R., Matsuno, S., & Shobugawa, Y. (n.d.). The South to North Variation of Norovirus Epidemics from 2006–07 to 2008–09 in Japan. PLOS ONE : accelerating the publication of peer-reviewed science. Retrieved October 4, 2013, from http://www.plosone.org/articleinfo%3Adoi