Re: Could Sulfur Gases Prevent Respiratory Infections?
http://www.ncbi.nlm.nih.gov/pubmed/189703
Ozone inhalation caused pronounced inhibition of influenza virus growth in mousenoses
sulfur dioxide (6 ppm for 7 days) caused partial inhibition
Neither gas altered the propagation of influenza in the lungs
The inhibitory effect of ozone and sulfur dioxide on influenza virus growth in nasal epithelium
suggests a competitive interaction between the chemical inhalant, the virus, and host tissues,
http://aem.asm.org/cgi/reprint/44/3/723.pdf
http://www.sciencedirect.com/scienc...serid=10&md5=c6e66789d6c38c5ca698d3aaec498188
mice were exposed to influenza and sulfur dioxide,alone and in combination.
Temperature, relative humidity and length of exposure were all controlled.
Virus exposure produced pneumonia even at low dose.
Sulfur dioxide produced pneumonia at higher doses, but appeared to have an
inverse effect at lower doses
The two combined produced more pneumonia than either one did separately.
Sulfur dioxide produced more weight reduction than influenza virus,
and combination exposures produced more weight reduction than either
stimulus did separately.
http://www.netl.doe.gov/technologie...ty_research/health_effects/pdfs/AppendixB.pdf
virus shedding. It has been suggested
that mechanisms of asthmatic sensitivity
may be associated with a wild-type allele
of the TNF-alpha promoter
polymorphism or may involve mast cell
degranulation.
Non-Clinical Studies
Increased mortality and decreased
survival time was observed in a group of
female mice with respiratory infection
exposed to 10 ppm for up to 3 weeks
compared to non-exposed controls. Mice
exposed to 0.03 to 0.1 ppm and an
influenza virus developed antibodies to
the virus more rapidly than mice
exposed to the virus alone. The study
authors postulate from this that SO2
alters nasal mucus membranes thereby
decreasing a defensive barrier to disease
and resulting in increased severity of
influenza infection. However, another
study reported that exposure to 6 ppm
for 7 days resulted in partial inhibition of
influenza virus growth in the nasal
epithelium and no propagation in the
lungs. Studies on guinea pigs suggested
that exposure to low levels of SO2 (1
ppm) might enhance the development of
ovalbumin-induced asthmatic reactions
and reported a significant increase in
ovalbumin-specific antibodies in serum
and bronchoalveolar fluid with exposure
to 0.1 to 16.6 ppm for 8 hours/day for 5
days. A study on mice exposed to 250
ppm for 3 hours reported an increased
uptake of iron in airway epithelium. The
clinical significance of many of these
studies is unclear and not discussed in
the studies themselves.
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Giddens and Fairchild (1972) exposed
mice to 10 ppm SO2 for 4 to 72 hours to
observe the effect of SO2 exposure on
the nasal and respiratory tracts. Lesions
consisting of edema, necrosis, and
desquamation of the olfactory and
respiratory epithelium were observed at
24-hour and longer exposures. More
injury was observed in the nasomaxillary
turbinates than in the rest of the
respiratory tract (Study ID .. 191).
Ukai (1977) investigated the effect of
SO2 exposure (0.03 to 0.1 ppm for 4
weeks) on upper respiratory infection
response in mice inoculated with
influenza virus. More rapid and more
severe inflammatory response, as well as
more rapid development and higher
levels of HI titer were observed in the
SO2-exposed mice (Study ID .. 207).
Fairchild (1977) observed an inhibition
in the growth of influenza virus in the
noses of mice exposed to 6 ppm of SO2
for 7 days. Virus propagation was not
altered (Study ID .. 238).
Hanacek (1987) investigated the effect
of SO2 on cough and expiratory reflexes
of 22 anaesthetized rabbits. Exposure to
200-300 ppm SO2 for 10-15 minutes
resulted in decreases in both
mechanically stimulated cough
excitability and cough reflex strength in
rabbits. Reporting of the experimental
methods and results lack detail (Study
ID ..300).
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Fairchild et al. (1972) investigated the
effect of exposure to SO2 on influenzal
pneumonia in mice. Mice were exposed
to concentrations ranging between 3.4
and 34.5 ppm continuously for up to 7
days. When SO2 was administered after
virus exposure, significantly increased
incidence of pneumonia was observed at
19 ppm and greater. When the virus was
administered after SO2 exposure, a
significant increase in pneumonia
incidence occurred only at 25 ppm after
4 to 7 days of exposure.
Histopathological effects were observed
at SO2 concentrations of 27 ppm and
greater after 7 days of continuous
exposure (Study ID .. 182).
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Ukai (1977) investigated the effect of
exposure to low levels (0.03 to 0.1 ppm)
of SO2 on the pathogenesis of influenza
virus infection in mice. In mice exposed
to both SO2 and the virus, antibodies to
the virus developed more rapidly than in
those mice exposed to virus alone. In
addition, mice exposed to SO2 but not
the virus showed an increase in the
number of goblet cells in nasal epithelial
cells. These observations suggest that
SO2 alters the nasal mucus membranes,
eliminating a major defensive barrier
against disease and subsequently
resulting in increased severity of
influenza infection (Study ID .. 207).
Fairchild (1977) investigated the effects
of SO2 on the growth of influenza virus
in the nasal epithelia of mice. Exposure
to 6 ppm SO2 for 7 days caused partial
inhibition of influenza virus growth in
the nasal epithelium and no propagation
in the lungs (Study ID .. 238).
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Increased mortality and decreased
survival time was observed in a group of
female mice with respiratory infection
exposed to 10 ppm for up to 3 weeks
compared to non-exposed controls. Mice
exposed to 0.03 to 0.1 ppm and an
influenza virus developed antibodies to
the virus more rapidly than mice
exposed to the virus alone. The literature
suggests that SO2 alters nasal mucus
membranes thereby decreasing a
defensive barrier to disease and
resulting in increased severity of
influenza infection. However, another
study reported that exposure to 6 ppm
for 7 days caused partial inhibition of
influenza virus growth in the nasal
epithelium and no propagation in the
lungs. Studies on guinea pigs suggested
-----------------------------------------------
Fairchild,G., J.Roan, and J.McCarroll. 1972. Atmospheric pollutants and the
pathogenesis of viral respiratory infection: sulfur dioxide and influenza infection.
Archives of Environmental Health 25:174-182.
Ref ID: 182
Fairchild,G. 1977. Effects of ozone and sulfur dioxide on virus growth in mice. Archives
of Environmental Health 32:28-33.
Ref ID: 238
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Table 3D ? ?Positive? Respiratory Effects Associated With Short-term Exposure to
SO2: Animal Toxicology Studies ? Greater Than 7 Day Exposures
Concentration
ppm
(mg/m3)
Effects Exposure
Duration
0.03 (0.08) ..More rapid and more severe inflammatory response to influenza infection (to 0.1
ppm; Mice)207
4 weeks
10 (26) ..Increased concentrations of cholesterol, total lipids, gangliosides and decreased
phospholipids (Guinea pigs)163
1 hr/d x 30d
100 (262) ..Decreased glutathione concentration and inflammation (Rats)251 5hr/d, 7 to 28d
150 (393) ..Increased lung resistance, decreased breathing frequency (Rabbits)239 12 x 3hr
600 (1573) ..Increase in solid material recovered by bronchial lavage (Rats)250 3 hr/d for 9,18,
or 30 d
---------------------------------------------
Table 6. Respiratory Health Effects Associated with Short-term Exposure to SO2
Summary of ?Positive? Findings: Clinical and Non-clinical studies
Concentration
(ppm)
Effects
0.03 ..More rapid and more severe inflammatory response to influenza infection (to 0.1 ppm; Mice)207
--------------------------------------------------
0.1 ..Increased respiratory pause (Guinea pigs)259
..Slight reduction in FEV1, Vmax 50 (AC)277
..Bronchoconstriction at lower concentrations in dry air than humidified air (HA)057
..Slight reduction in lung clearance (Rats)235
..Increased antigen-specific antibodies in serum and bronchoalveolar fluid (Guinea pigs)133
0.15 ..Decreased specific a
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..Increased frequencies of polychromatic erythrocyte formation (Mice)380
6 ..Inhibition of influenza virus growth in mice exposed for 7 days238
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Study ID Reference SO2
Concentration
Time Species/Population
Group
Effect
..207 Ukai, 1977 0.03 to 0.1 ppm 4 wk Mice More rapid and more severe
inflammatory response to influenza
infection
..238 Fairchild, 1977 6 ppm 7 d Mice Inhibition of virus growth
..300 Hanacek, 1987 200-300 ppm 10-15 min Rabb
----------------------------------------------------
..238 Fairchild, 1977 6 ppm 7 d Mice Inhibition of influenza virus growth
..134 Trimpe et al., 1986 27 ppm Not clear Hamsters No difference in bacterial clearance
rates
..259 Park et al., 2001 0.1 ppm 5 hr/d, 5 d Guinea pigs Enhanced ovalbumin-induced
asthmatic reactions
..133 Riedel et al., 1988 0.1 to 16.6 ppm 8 hr/d, 5 d Guinea pigs Increased ovalbumin-specific
antibodies and bronchoalveolar fluid
..201 Gause and
Rowlands, 1975
Unclear Not reported Human lymphocyte
membranes
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More rapid and more severe
inflammatory response to influenza
infection (to 0.1 ppm; Mice)207
(4 weeks)