Objective—To compare the virulence of spores of 7
fungi by tracheal inoculation of goats following exposure
of goats to an aerosol of sterilized feedyard dust.
Animals—54 weanling Boer-Spanish goats.
Procedure—A prospective randomized controlled
study was conducted. There were 7 fungal treatment
groups, a tent control group, and a pen control group
(n = 6 goats/group). Goats in the 7 treatment and tent
control groups were exposed to autoclaved
aerosolized feedyard dust for 4 hours in a specially
constructed tent. Goats in the 7 treatment groups
were then inoculated intratracheally with 30 mL of a
fungal spore preparation, whereas tent control goats
were intratracheally inoculated with 30 mL of physiologic
saline (0.9% NaCl) solution. These treatments
were repeated each week for 6 weeks.
Results—Severity of pathologic changes differed significantly
among the 7 fungal treatment groups as
determined on the basis of gross atelectatic and consolidated
lung lesions and histologic lesions of the
lungs. Descending order for severity of lesions was
Mucor ramosissimus, Trichoderma viride,
Chaetomium globosum, Stachybotrys chartarum,
Aspergillus fumigatus, Penicillium chrysogenum, and
Monotospora lanuginosa. Trichoderma viride spores
were the most invasive and were isolated from the
bronchial lymph nodes and thoracic fluid of all 6 goats
administered this organism. Spores were observedhistologically
in lung tissues harvested 72 hours after
inoculation from all treatment groups.
Conclusions and Clinical Relevance—4 of 7 fungal
spore types induced significantly larger lung lesions,
compared with those induced by the other 3 spore
types or those evident in control goats. (Am J Vet Res 2005;66:615–622)
Objective—To determine effects of repeated aerosol
exposures to fly ash dust on respiratory tracts of tent-confined
Animals—12 weanling Boer-Spanish crossbred
Procedure—Goats were randomly assigned to 2
groups: fly ash treatment group (principal goats,
n = 6) or control group (control goats, 6). Aerosolized fly
ash dust was provided during a 4-hour period for each
of 6 applications given over 3 months and one 2-hour
application prior to necropsy. Fly ash particle diameters
ranged from 0.1 to 130 µm and averaged 17.8 µm, with
1.5% of fly ash particles in the 0.1- to 5-µm-diameter
range. A mean ± SD of 748 ± 152 g/treatment was
delivered inside a tent containing principal goats; control
goats were placed inside a similar tent for 4-hour
treatments without dust. Following treatment, rectal
temperatures were taken at 0, 4, 6, 8, 24, and 72
hours; Hcts were recorded at 0, 24, and 72 hours.
Results—Rectal temperatures were significantly
increased at 4, 6, and 8 hours and decreased at 72
hours, compared with 0 hours. Mean ± SEM Hct values
were significantly increased for principal goats
(37.47 ± 0.39%), compared with control goats (36.17
± 0.42%). A significant increase in the mean area of
gross atelectatic lung lesions (1,410 mm2) was found
in principal goats (n = 6), compared with control goats
(440 mm2; 5).
Conclusions and Clinical Relevance—An increase
in atelectatic lung lesions was observed in principal
goats, compared with control goats; however, overall,
fly ash dust effects were nontoxic. ( Am J Vet Res 2005;66:991–995)
Objective—To investigate the effects of sterile fine dust aerosol inhalation on antibody responses and lung tissue changes induced by Mucor ramosissimus or Trichoderma viride spores following intratracheal inoculation in goats.
Animals—36 weanling Boer-Spanish goats.
Procedures—6 goats were allocated to each of 2 M ramosissimus–inoculated groups, 2 T viride–inoculated groups, and 2 control (tent or pen) groups. One of each pair of sporetreated groups and the tent control group were exposed 7 times to sterilized fine feedyard dust (mean ± SD particle diameter, < 7.72 ± 0.69 μm) for 4 hours in a specially constructed tent. Goats in the 4 fungal treatment groups were inoculated intratracheally 5 times with a fungal spore preparation (30 mL), whereas tent control goats were intratracheally inoculated with physiologic saline (0.9% NaCl) solution (30 mL). Pen control goats were not inoculated or exposed to dust. Goats received an IV challenge with equine RBCs to assess antibody responses to foreign antigens. Postmortem examinations were performed at study completion (day 68) to evaluate lung tissue lesions.
Results—5 of 7 deaths occurred between days 18 and 45 and were attributed to fine dust exposures prior to fungal treatments. Fine dust inhalation induced similar lung lesions and precipitating antibodies among spore-treated goats. Following spore inoculations, dust-exposed goats had significantly more spores per gram of consolidated lung tissue than did their nonexposed counterparts.
Conclusions and Clinical Relevance—Fine dust inhalation appeared to decrease the ability of goats to successfully clear fungal spores from the lungs following intratracheal inoculation.
Objective—To determine the clinical, clinicopathologic,
and histologic effects of aerosolized feedyard dust
that contains natural endotoxins on adult sheep.
Animals—Eighteen 3-year-old Saint Croix sheep.
Procedure—A prospective randomized controlled
study was conducted. There were 2 treatment groups
(dust-endotoxin group, n = 9; control group, 9).
Aerosolized feedyard dust was provided continuously
during a 4-hour period for each application (once in week
1, 3 times in week 2, and 7 times in week 3) to sheep in
a semiairtight tent. All sheep were euthanatized and
necropsied 8 hours after the treatment group received
the last dust treatment. Variables measured before and
after each dust treatment were rectal temperature,
total WBC count, and concentrations of fibrinogen
Results—Mean amount of dust administered during
each treatment was 451 g/4 h. Filter collection indicated
51 mg of dust/m3 and 7,423 ng of endotoxin.
Mean rectal temperature at 8 hours (40.4 C) and
mean WBC counts 12 and 24 hours after dust treatment
were significantly higher for the treated group
than the means of the respective variables for the
control group. Similar responses were observed with
repeated dust-endotoxin treatments; however, with
each subsequent treatment, there was a diminished
response. Sheep in the treatment group had generalized
alveolar septal thickening and hypercellularity.
Conclusion and Clinical Relevance—Feedyard
dust induced a temporary febrile response and leukocytosis
in sheep in the treatment group. Exposure to
dust that contains endotoxins may be a stressor preceding
acute infectious respiratory tract disease of
marketed sheep. (Am J Vet Res 2002;63:28–35)