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Public release date: 14 January 2008
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Dipl.-Ing. Wilfried Soddemann
Free Science Journalist
soddemann-aachen@t-online.de
http://www.dugi-ev.de/information.html
Epidemiological analysis:
http://www.dugi-ev.de/TW_INFEKTIONEN_H5N1_20071019.pdf
Norovirus infections: Triggered off by drinking water
Norovirus infections:
Triggered off by drinking water in the run-up to limited secondary
spread from human to human
The cold is the main factor to conserve virulent viruses e.g. in water.
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.
Half of norovirus infections occur in expanse without recognized
clusters. 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. Norovirus infections exact start and finish
at water pipe temperatures of 15°C. So I\'m convinced that norovirus
infections mainly are triggered off by drinking water in the run-up to
limited secondary spread from human to human.
There is no other appropriate vehicel changing its temperature over the
year to explain the strong seasonal norovirus epidemics in the cold.
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 minimum temperature february/march: important to viruses like
norovirus and rotavirus - maximum temperature august: important to
bacteria like salmonellae and campylobacter). Norovirus (and rotavirus,
salmonellae, 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 have
to be triggered off by contaminated drinking water in the run-up to
limited secondary spread from human to human.
The performance to eliminate viruses from the drinking water processing
plants regularly does not meet the requirements of the WHO and the
USA/USEPA. Conventional disinfection procedures are poor, because
microorganisms in the water are not in suspension, but embedded in particles.
Conventional disinfection procedures (chlorine, ozone) are less
effective in the cold. Even ground water used for drinking water is not free
from viruses.
Extracts from the specialized literature:
http://www.springerlink.com/content/x6138263qn388085/
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz
Volume 50, Number 3 / März 2007
K. Botzenhart
Konrad.Botzenhart@uni-tuebingen.de
Institut für Medizinische Mikrobiologie und Hygiene, Wilhelmstraße
31, 72074 Tübingen, BRD
Viruses in drinking water
Abstract
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,
http://www.cdc.gov/ncidod/EID/vol11no11/05-0487.htm
Emerg Infect Dis [serial on the Internet]. 2005 Nov.
Maunula L, Miettinen IT, von Bonsdorff C-H.
Norovirus outbreaks from drinking water.
Abstract
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.
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