Friday, 11 January 2008

Norovirus vomiting bug

An estimated 3 million people have this year caught the Norovirus vomiting bug this winter, a stomach bug which causes diarrhoea and vomiting. Symptoms will begin around 12 to 48 hours after infection and will usually last 12 to 60 hours. Most people make a full recovery within one or two days, however some (usually the very young or elderly) may become very dehydrated and require hospital treatment. The norovirus season had started "uncharacteristically early", with a greater number of cases nationally from the first week of November. Improved reporting and testing may have contributed to the increase. It's estimated that, in a typical year in the United States, 23 million people are infected, some 50,000 of them are hospitalized, and 300 die.

I got it myself last week, very unpleasant few days I can tell you. I didn’t report it to anyone however, just kept drinking lots of water and waited for it to stop. You can get oral rehydration fluid from chemists that replaces nutrients when you cant keep food down.

"Infections from the debilitating Norovirus stomach bug will peak this week as millions return to work after the holidays and spread the germs, the government has warned. The virus, which was responsible for closing more than 100 hospital wards last week and Doctors estimate that more than 100,000 people a week are catching the infection - and the rate may peak this week as the virus takes the opportunity to spread in the workplace and classrooms.

There are rumours that the official secrets act had been invoked by the government to cover up the extent of the problem. It may be linked to bird flue, whatever it is any attempt at a cover-up is sure to make it worse.


Dipl.-Ing. Wilfried Soddemann said...

Norovirus infections:
Triggered off by drinking water in the run-up to secondary spread from human to human

In temperate climates the strong seasonal waterborne infections like norovirus, rotavirus, salmonellae and campylobacter are mainly triggered off by drinking water dependent on the drinking water temperature (in Germany min. february/march: important to norovirus and rotavirus – max. august: important to salmonellae and campylobacter). Norovirus infections start and finish at water pipe temperatures of 15°C. Norovirus (and rotavirus, salmonellae and campylobacter) infections are triggered off by feces in food or in drinking water. The year over food temperature don’t change, in contrast to drinking water temperature. Logical norovirus infections are triggered off by contaminated drinking water in the run-up to secondary spread from human to human.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz
Volume 50, Number 3 / März 2007
K. Botzenhart
Institut für Medizinische Mikrobiologie und Hygiene, Tübingen, BRD Institut für Medizinische Mikrobiologie und Hygiene, Wilhelmstraße 31, 72074 Tübingen, BRD

Viruses in drinking water

Viruses in drinking water can cause infectious diseases. In the past, hepatitis A and E were the most frequently observed drinking- water-borne viral infections, but in recent years several small- and large-scale norovirus epidemics have been described, even in Europe. All virus species spread via drinking water are of fecal origin. They are regularly identified in waste water even after conventional multi-stage water treatment. The approved disinfection methods can cope with these viruses if they are not integrated in larger particles. For this reason particle separation is particularly important in water treatment. Virological tests are not reliable enough to ensure that drinking water is sufficiently virus-free. The examination of 100 mL of water for E. coli and coliform bacteria is not adequate proof either. If potentially contaminated raw water is used, consumer safety must be ensured by calculating the performance of water treatment plants on a case-by-case basis. Such a calculation takes into account the virus load of the raw water, the efficiency of the physical and chemical particle elimination steps and the effect of disinfection. Those factors which determine the effectiveness of disinfection, namely concentration and exposure time or UV radiation strength, must be adjusted according to the risk of viral infection, and calculated settings must be adhered to, even if favorable E. coli levels may make them seem excessive.
Keywords: Drinking water, Viruses, Disinfection, Particle elimination,
Emerg Infect Dis [serial on the Internet]. 2005 Nov.
Maunula L, Miettinen IT, von Bonsdorff C-H.

Norovirus outbreaks from drinking water.

As part of an intensified monitoring program for foodborne disease outbreaks in Finland, waterborne outbreaks were investigated for viruses. The diagnostic procedure included analysis of patients' stool samples by electron microscopy and reverse transcription–polymerase chain reaction (RT-PCR) for noroviruses and astroviruses. When these test results were positive for a virus, the water sample was analyzed. Virus concentration was based on positively charged filters from 1-L samples. Of the total 41 waterborne outbreaks reported during the observation period (1998–2003), samples from 28 outbreaks were available for analysis. As judged by RT-PCR results from patient samples, noroviruses caused 18 outbreaks. In 10 outbreaks, the water sample also yielded a norovirus. In all but 1 instance, the amplicon sequence was identical to that recovered from the patients. The ubiquity of waterborne norovirus outbreaks calls for measures to monitor water for viruses.

Dipl.-Ing. Wilfried Soddemann
Free Science Journalist
Epidemiological analysis:

Adrian Windisch said...
says 'The norovirus can be spread through contact with an infected person, through contact with surfaces, or objects, that are contaminated with the virus, or by eating contaminated food or water'. so I'm not sure your correct to emphasize transmission through water quite so much.

Dipl.-Ing. Wilfried Soddemann said...

Norovirus can spread through

- contact with infected persons at 37°C
- contact with surfaces or objects in [heated] houses at 20°C
- eating contaminated food with over the year constant temperatures
- drinking contaminated water with over the year changing temperatures from 20°C to 3°C.

About the half of norovirus infections occur without recognized clusters in the expanse. Norovirus infections occur general strong seasonal in the cold dependent on environmental temperatures [water, soil, drinking water pipes]. There must be an abiotic vehicel like drinking water, that changes its temperature in the cold. So I'm convinced that norovirus infections are triggered off by drinking water in the run-up to limited secondary spread from human to human. About the half of the infected humans is infected here and there triggered off by cold drinking water.

I'm sorry that I can not post the graphs to show the coherence between seasonal norovirus epidemics and the temperatures of water bodies as cold soil 1 meter deep as water pipes in 1 m depth.

There is no other appropriate vehicel changing its temperature over the year to explain the strong seasonal norovirus epidemics. Norovirus infections exact start and finish at water pipe temperatures of 15°C.The cold is the main cause to conserve virulent viruses e.g. in water.

Dipl.-Ing. Wilfried Soddemann

Anonymous said...

Wilfried, you appear to be claiming that humans are involved in secondary transmission and that water is the key player here. I thought Pasteur killed the "spontaneous generation" idea. Where do these viruses in the water come from in the first place? All viruses need a living host in order to replicate; they don't replicate in the water. In addition, all infectious agents have a minimum infectious dose. Do you know what they are for the diseases in question here when ingested? By the way what are your credentials in the fields of virology/microbiology? Where have you published your findings (I am talking scientific journals here and not blog comments boxes)? - A Virologist