Studies have also implicated the natural environment as a source of C.
botulinum spores. The organism causing infant botulism is usually the
type found in the soil of the area where the illness occurs. C.
botulinum has been isolated from environmental samples such as yard
soil and vacuum cleaner dust in comparable frequencies from both
case-associated and control homes in California.

In Australia, the illnesses were associated with the organisms found
in yard soils and drinking water. In Japan, C. botulinum type A
organisms were detected not only in the honey fed to the infant before
onset of illness but also in soil samples taken at the entry to the
home and vacuum cleaner dust.

The disease was found more often in infants who were white, had older
mothers, and had mothers with more years of formal education. An
important finding to these investigators was that illness in infants
less than 2 months old was epidemiologically different from that in
infants 2 months old or older. One risk factor for infants less than 2
months old was living in a rural area or on a farm; breast feeding was
not a risk factor.

One other factor that was considered was the disturbance of soils by
agricultural and construction activities preceding the infant's
illness. Possibly, disturbance of soils by earthquakes should also be
included.

Interestingly, there appeared to be a cluster of three infant botulism
cases in Southern California following the January 1994 earthquake in
the Northridge area, north of Los Angeles. Several parents of infant
botulism cases remarked to the press about the clouds of dust that
were encountered prior to the illness of their infants.

In Colorado, three infants developed type A botulism within a 6-month
period in 1981. The families lived near each other in mobile homes. A
common link was that two of the infants had used the same crib. The
first infant had used the crib until 1 month after his illness. The
crib then was used by a second nonaffected infant and then given to a
third infant, who later developed infant botulism. However, the common
finding in all three cases was the presence of a C. botulinum type A
organism in environmental samples, including the crib, soils, and
household dust.

In Pennsylvania, a case-control study of risk factors associated with
infant botulism revealed that the infants were white, were primarily
breast-fed, and had type B botulism. More than half of the fathers had
daily contact with soil.

source:

Update: Infant Botulism
THADDEUS F. MIDURA

CLINICAL MICROBIOLOGY REVIEWS
Apr. 1996, p. 119–125 Vol. 9, No. 2
Copyright 1996, American Society for Microbiology

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