VM2 - G18 by Fizakir

fizazakir — 2017-04-03 13:51:45 UTC

Please attach your sources (journals, articles) here. We'll do our discussion here. TQ.

Ecology

asyiqinaddenan — 2017-04-07 16:30:01 UTC

The host cell range of Noroviruses
- mice
- cow
- pigs
- human

Characteristicis:
- Human Norovirus does have a binding specificity within the human species, however. ABH and Lewis histo-blood group antigens are carbohydrate epitopes present throughout many tissue of the human body.
- The type 1 and 3 chain ABH histo-blood group antigens are present on mucosal epithelial cell surfaces and in salivary secretions, with variations in the carbohydrates in different individuals based on their secretor status and blood type.
- Norovirus likely attaches to either H types 1 or 3 present on gastroduodenal epithelial cells.
- Norovirus virus-like particles bound poorly to saliva containing ABH antigens in blood group B individuals, and may also account for the observation that blood group B individuals are more resistant to NV challenge.
-Not all Norovirus infections are in humans These are just some recently proposed mechanisms for the ways in which the Human Norovirus may select for its human host.
- Norovirus spreads best in a common source such as water or food. It is incredibly infectious—as it takes as few as 10-100 particles to spread. Its environmental impacts are almost exclusively pathogenic.

Noroviruses: The Perfect Human Pathogens?

asyiqinaddenan — 2017-04-07 16:33:02 UTC

Characteristics

- highly contagious

- rapidly and prolifically shed

- constantly evolving

- evoke limited immunity

- have low infectious dose

- environmentally stable (can survive both freezing and heating)

- resistant to many common chemical disinfectants

Causes

- endemic diarrheal disease

- foodborne disease

- gastroenteritis outbreaks

Transmission

- direct contact

- ingestion of contaminated food or water

- handling of contaminated fomites

- ingestion of aerosolized particles

https://academic.oup.com/jid/article/205/11/1622/844989/Noroviruses-The-Perfect-Human-Pathogens

Norovirus Surveillance: An Epidemiological Perspective

asyiqinaddenan — 2017-04-07 16:35:03 UTC

Outbreaks
- Analysis of these data showed that >25% of outbreaks reported from 1992 to 2008 were in hospitals and that around 80% of the outbreaks were either suspected or confirmed to be due to norovirus. This period saw >1800 outbreaks of norovirus infection reported in hospitals in England, affecting >45 000 patients and staff. The seasonality of norovirus infection outbreaks was also clearly demonstrated, with increasing activity occurring in the winter months. Furthermore, differences were observed showing that some winter seasons had considerably more outbreak reports than others, particularly in 2002, when the emergence of the new GII.4 strain of norovirus was detected in Europe
https://academic.oup.com/jid/article/213/suppl_1/S8/2473361/Norovirus-Surveillance-An-Epidemiological

Norovirus in the News – What You Need to Know

asyiqinaddenan — 2017-04-07 16:35:49 UTC

Morphology
-The Norwalk agent was the first virus that was identified as causing gastroenteritis in humans, but recognition of its importance as a pathogen has been limited because of the lack of available, sensitive, and routine diagnostic methods.

-The round blue ball structure of norovirus is actually a protein surrounding the virus’s genetic material. The virus attaches to the outside of cells lining the intestine, and then transfers its genetic material into those cells. Once the genetic material has been transferred, norovirus reproduces, finally killing the human cells and releasing new copies of itself that attach to more cells of the intestine’s lining.

- Norovirus (previously called “Norwalk-like virus” or NLV) is a member of the family Caliciviridae.
- derives from the Latin for chalice—calyx—meaning cup-like, and refers to the indentations of the virus surface.
- The family of Caliciviridae consists of several distinct groups of viruses that were first named after the places where outbreaks occurred.
- The first of these outbreaks occurred in 1968 among schoolchildren in Norwalk, Ohio. The prototype strain was identified four years later, in 1972, and was the first virus identified that specifically caused gastroenteritis in humans.
- Other discoveries followed, with each strain name based on the location of its discovery—e.g., Montgomery County, Snow Mountain, Mexico, Hawaii, Parmatta, Taunton, and Toronto viruses.- A study published in 1977 found that the Toronto virus was the second most common cause of gastroenteritis in children. Eventually this confusing nomenclature was resolved, first in favor of calling each of the strains a Norwalk-like virus, and then simply, a norovirus – the term used today.

http://www.foodpoisonjournal.com/food-poisoning-information/norovirus-in-the-news-what-you-need-to-know/#.WOe_lIiGPIU

Global Economic Burden of Norovirus Gastroenteritis

asyiqinaddenan — 2017-04-07 16:36:36 UTC

There are several possible reasons for comparative lack of attention towards norovirus:
- disease burden has been challenging to estimate, in part because diagnostics of adequate sensitivity have not been widely available.
- some associate norovirus primarily with outbreaks in cruise ships and healthcare facilities however, of the estimated 20 million annual cases in the United States, only a small fraction (<1%) are associated with reported outbreaks.
- Although norovirus is perceived to only cause self-limiting, mild gastroenteritis that rarely requires medical care, causes severe disease, or death, there are an estimated 70,000 norovirus-associated deaths among children <5 years annually worldwide.
- Also, funding organizations and policy makers that focus on low- and middle-income countries (LMICs) may consider norovirus more of a priority for higher income countries, as those are the settings in which most norovirus data are generated.

Norovirus prevention and control measures
- e.g., antiviral, disinfectants, and, most notably, vaccines
- understanding the global economic burden of norovirus is increasingly timely and critical.
- Decision makers such as funders, policy makers, public health officials, and product developers need more economic information to determine where norovirus should fall on their list of priorities and how much time, effort, and resources to invest.
-there has not been a systematic international assessment of the cost of norovirus. Thus, we developed a computational simulation model that can estimate the economic burden of norovirus in each country/area (i.e., territory/state) by WHO region and globally.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0151219

Outbreaks

fatinadila267 — 2017-04-10 04:21:33 UTC

Most outbreaks of norovirus illness happen when infected people spread the virus to others. But, norovirus can also spread by consuming contaminated food or water and touching things that have the virus on them.

Norovirus is the leading cause of illness and outbreaks from contaminated food in the United States. About 50% of all outbreaks of food-related illness are caused by norovirus. Food can get contaminated with norovirus at any point when it is being grown, shipped, handled, or prepared.

Foods that are commonly involved in outbreaks of norovirus illness are—

leafy greens (such as lettuce),
fresh fruits, and
shellfish (such as oysters).

But, any food that is served raw or handled after being cooked can get contaminated.

https://www.cdc.gov/norovirus/trends-outbreaks.html

Norovirus causing Food Poisoning

n_nasiha23 — 2017-04-15 11:16:29 UTC

How Norovirus Spread In the Kitchen

n_nasiha23 — 2017-04-15 11:19:47 UTC

1) improper hand washing.
- proper hand washing is necessary to remove bacteria
2) having contaminated food contact surfaces and utensils
3) hand contamination of ready to eat food
- use gloves while handling food to prevent from bare hand contact
4) Failure to separate raw animal food from ready to eat food.

Outbreaks

fatinadila267 — 2017-04-16 02:54:28 UTC

Most outbreaks of norovirus illness happen when infected people spread the virus to others. But, norovirus can also spread by consuming contaminated food or water and touching things that have the virus on them.
Norovirus is the leading cause of illness and outbreaks from contaminated food in the United States.
About 50% of all outbreaks of food-related illness are caused by norovirus. Food can get contaminated with norovirus at any point when it is being grown, shipped, handled, or prepared.
Foods that are commonly involved in outbreaks of norovirus illness such as:

leafy greens (lettuce),
fresh fruits
shellfish (oysters).

But, any food that is served raw or handled after being cooked can get contaminated.
https://www.cdc.gov/norovirus/trends-outbreaks.html

Common Norovirus Outbreak Settings

fatinadila267 — 2017-04-16 03:06:38 UTC

Norovirus in Healthcare Facilities

Health care facilities including nursing homes and hospitals are the most commonly reported settings for norovirus outbreaks in the United States and other industrialized countries Over half of all norovirus outbreaks reported in the United States occur in long-term care facilities.
The virus can be introduced into healthcare facilities by infected patients—who may or may not be showing symptoms—or by staff, visitors, or contaminated foods.

Norovirus in Restaurants and Catered Events

Most norovirus outbreaks from contaminated food occur in food service settings like restaurants. Infected food workers are frequently the source of these outbreaks, often by touching ready-to-eat foods, such as raw fruits and vegetables, with their bare hands before serving them.
Foodborne outbreaks of norovirus illness have also occurred in banquet halls, and even at family dinners, where people eat food handled or prepared by others.
For example, oysters harvested from contaminated water and raspberries irrigated with contaminated water have caused norovirus outbreaks.

https://www.cdc.gov/norovirus/trends-outbreaks.html

Interventions: How to Prevent Growth of Norovirus in Foods

nsakinah_ak — 2017-04-16 05:36:55 UTC

4. Clean and disinfect contaminated surfaces

After throwing up or having diarrhea, immediately clean and disinfect the contaminated surfaces. Use a bleach-based household cleaner as directed on the product label or a solution made with 5 tablespoons to 1.5 cups of household bleach per 1 gallon of water.

5. Wash laundry thoroughly

Immediately remove and wash clothing or bedding that may be contaminated with vomit or stool (feces). Handle the soiled items carefully without agitating them, wear rubber or disposable gloves and wash your hands after, and wash the soiled items with detergents at the maximum available cycle length then machine dry them. Use hot water and soap to clean them.

6. Exclude infected people from childcare, preschool, school, and work

Wait until there has been no vomiting or diarrhea for 24 hours. For infected food handler, the exclusion period should be until there has been no diarrhea and vomiting for 48 hours. Avoid traveling until signs and symptoms have ended.

https://www.cdc.gov/norovirus/preventing-infection.html
http://www.sahealth.sa.gov.au/wps/wcm/connect/public+content/sa+health+internet/health+topics/health+conditions+prevention+and+treatment/infectious+diseases/norovirus+infection

Interventions: How to Prevent Growth of Norovirus in Foods

atuladawiyah13 — 2017-04-16 06:40:19 UTC

1. Practice proper hand hygiene

Wash hands carefully with soap and water. if soap and water are not available, use an alcohol based-hand sanitizer. These alcohol based-hand sanitizer can help reduce the number of germs on hands but it is not a substitute for washing with soap and water.

2. Take care in kitchen

Carefully wash fruits and vegetables before preparing and eating them. Cook oysters and other shellfish thoroughly before eating.

3. Do not prepare food while infected

People with norovirus illness should not prepare food for others while they still have the symptoms and for at least two days after they recover from their illness. The example of illness is flu.

https://www.cdc.gov/features/norovirus/

Nutrition required for Norovirus to grow

faizabahrudin — 2017-04-16 15:11:23 UTC

Norovirus can survive in any food condition. Most are found in:
- Raw fruits and vegetables
- Cold ready-to-eat food

Foods may contaminate during preparation may be through infected handler

(Michael W. Smith (2017). Norovirus: Symptoms and Treatment. Retrieved from http://www.webmd.com/food-recipes/food-poisoning/norovirus-symptoms-and-treatment)

Biochemical Tests

cutiedoc96 — 2017-04-16 16:31:33 UTC

Laboratory diagnosis:
- Focus on detecting viral RNA or viral antigen.
- Most public health and clinical virology laboratories test for norovirus by using real-time reverse transcription-polymerase chain reaction (RT-qPCR) assays.
- Enzyme Immunoassays and Convetional RT-PCR Assays for Genotyping are also another methods used in detecting norovirus.

1. RT-qPCR.
- Are preferred laboratory method for detecting norovirus.
- Detects the genetic material (RNA) of the virus.
- These assays are very sensitive and can detect as few as 10 to 100 norovirus copies per reaction.
- They use different oligonucleotide primer sets to differentiate genogroup I and genogroup II norovirus.
- Also quantitative and can provide estimates of viral load.
- May be used to detect norovirus in stool, vomitus, foods, water and environmental specimens.

Biochemical test (continue)

aishah065240 — 2017-04-17 11:04:24 UTC

2. Enzyme Immunoassay
Rapid commercial assays, such as enzyme immunoassays (EIAs), detect norovirus antigen but these kits have poor sensitivity (50-75%) and are not recommended for diagnosing norovirus infection in sporadic cases of gastroenteritis.

3. Conventional RT-PCR Assays for Genotyping
Conventional RT-PCR followed by sequence analysis of the RT-PCR products is used for norovirus genotyping. Dual typing for norovirus is being implemented by laboratories participating in CaliciNet, a national laboratory surveillance network for norovirus outbreaks coordinated by CDC. This consist of RT-PCR amplification a partial region of both the polymerase gene and the capsid gene (region B-C) in a single reaction for either genogroup I or genogroup II viruses. The sequences obtained are compared to CaliciNet reference sequences for typing. An example of dual typing is the GII.P16-GII.4 Sydney norovirus strain.

Diagnostic Methods. (2017, February 01). Retrieved April 17, 2017, from https://www.cdc.gov/norovirus/lab-testing/diagnostic.html

Characteristic of Norovirus

husnaazhar939 — 2017-04-17 11:23:41 UTC

Noroviruses are a group of viruses belonging to the Norovirus genus and the Caliciviridae family. It is a small virus that contains RNA and is surrounded by a protein coating.Noroviruses contain a linear, non-segmented, positive-sense RNA genome of approximately 7.5 kbp, encoding a large polyprotein which is cleaved into six smaller non-structural proteins (NS1/2 to NS7) by the viral 3C-like protease (NS6), a major structural protein (VP1) of about 58~60 kDa and a minor capsid protein (VP2) The virus particles demonstrate an amorphous surface structure when visualized using electron microscopy and are between 27-38 nm in size.

2017-04-20 16:25:17 UTC

summary1

fizazakir — 2017-05-10 02:36:35 UTC

summary 2

fizazakir — 2017-05-10 02:37:31 UTC

summary3

fizazakir — 2017-05-10 02:38:15 UTC

summary4

fizazakir — 2017-05-10 02:38:34 UTC

summary5

fizazakir — 2017-05-10 02:39:10 UTC