As noted in prior posts, the key issue in toxic torts is
causation. Yet, how an illness, disease,
or adverse impact occurs is sometimes quite surprising. Only to illustrate the principle, I note two
recent reports that demonstrate the unexpected.
have long puzzled over why flu becomes so much more active in winter. A new
study reveals that dry air is one likely culprit. Scientists have proposed different
explanations for why influenza makes more people sick in temperate regions
during winter. One idea is that people
simply spend more time indoors together because it's colder, giving the virus
more opportunity to spread. Another idea
is that environmental factors affect the survival and transmission of the
virus. For example, laboratory studies
have found that higher temperatures affect the flu virus's coat. That could potentially explain why flu doesn't
spread during summer, but temperatures indoors, where most Americans spend the
bulk of their time, are often tightly controlled.
humidity is another suspect, but the data have not established a strong link
between relative humidity and flu outbreaks.
[Relative humidity is not a measure of the actual amount of moisture in
the air, but how close the air is to the point at which a "cloud" would start
to form.] Researchers decided to look more intensely at this issue. They reexamined laboratory data and found
that absolute humidity could account for the airborne survival and transmission
of the virus.
researchers compared death rates attributed to influenza over 31 years to
absolute humidity readings nationwide; they also used a mathematical model of
the influenza transmission cycle that incorporated previous findings of how
absolute humidity affects the survival and transmission of the virus. They reported that there were often
significant drops in absolute humidity in the weeks prior to a flu outbreak.
noting that this dry period is not a requirement for triggering an influenza
outbreak, they found it was present in 55-60% of the outbreaks analyzed. The causal link? The virus responded almost immediately to the
dry period with the result that transmission and survival rates increase. Further, about 10 days later, the observed
influenza mortality rates occurred apparently as a result, at least in
can be found at http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000316.
have long known that smokers and people exposed to secondhand smoke experience
high rates of respiratory infections.
The presumption has been that smoking impairs lung function or immunity,
which it may. However, a more
significant factor may be that cigarettes host hundreds of different bacteria,
including those responsible for many human illnesses.
extracted tobacco particles sitting atop filters or inside cigarette packaging
and placed the particles in a sterile culture medium that simulated human
lungs. In most cases, the researchers
were able to grow bacteria that had been present on the near-microscopic
flakes. The most prevalent bacteria
found to be present included Campylobacter, which can cause food poisoning;
Clostridium, Corynebacterium, Klebsiella, Pseudomonas aeruginosa, and
Stenotrophomonas maltophilia - all of which are associated with pneumonia and
other infections; E. coli; and, a number of Staphylococcus species that
underlie serious hospital-associated infections. The researchers note that it would be
worthwhile to explore if the bacteria came from tobacco and were not merely
reflective of environmental contamination.
can be found at http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info:doi/10.1289/ehp.0901201.
research also sheds light on this subject.
Researchers found, without identifying specific species, that toxins
produced by bacteria found in many filters (from tobacco particles embedded in
the filters) caused damage to or destroyed red blood cells.
can be found at http://www.ncbi.nlm.nih.gov/pubmed/18768459.
companies may be aware of this issue.
There is at least one patent that covers the use of an antibacterial
wash on fresh or partially cured tobacco as a cost-effective method "of
reducing both the numbers and activity of bacterial and fungal
populations." The patent points out that
these microbes are responsible for producing endotoxins and tobacco-specific
chemicals called nitrosamines.
Nitrosamines can cause cancer, and are a natural byproduct of the
burning of tobacco. It may also be that
arise from microbial degradation of tobacco components.
can be found at http://www.google.com/patents/about?id=foQQAAAAEBAJ&dq=6,755,200&as_drrb_ap=q&as_minm_ap=0&as_miny_ap=&as_maxm_ap=0&as_maxy_ap=&as_drrb_is=q&as_minm_is=0&as_miny_is=&as_maxm_is=0&as_maxy_is.
Thus, issues of causation can often be much more complex and
multifactorial than one would believe upon first impression.