To quantify dectin-1 expression in bronchoalveolar lavage fluid (BALF), create polyclonal antibodies against equine dectin-1 and localize it in tissues, and quantify fungal exposure in pastured and stabled asthmatic and nonasthmatic horses.
BALF samples from 6 controls and 6 horses with severe asthma. Stored lung and nasal wash samples.
Dectin-1 expression was quantified by quantitative PCR (qPCR). Purified peptide from equine dectin-1 was used to generate polyclonal antibodies and was confirmed with immunological testing. Fungal exposure was quantified in BALF samples by counting fungal-like intracellular particles in phagocytic cells, by qPCR quantification of the “universal” 18S rRNA fungal gene, and by quantifying 36 specific fungi in equine and dust samples using qPCR assays.
Equine dectin-1 was localized in tissues and cells, and functional isoforms were upregulated significantly in BALF after stabling. Pastured horses from both groups had low levels of fungi in BALF, and there was a significant increase in some specific fungi, most notably for Eurotium amstelodami, Wallemia sebi, and Aspergillus niger after stabling. However, stabled asthmatic horses had fewer phagocytized particles, less 18S rRNA signal, and fewer specific fungi compared to nonasthmatic horses.
Stabling increases exposure to fungi, but asthmatic horses had fewer fungi reaching their lower airways, presumably resulting from congestion and narrowing of the airways. Exposure to fungi could contribute to airway inflammation by increasing dectin-1 functional isoforms, and exposure to indoor molds should be avoided.
Objective—To determine whether results of physical
or radiographic examination or biochemical analyses
in adult racehorses with primary lung abscesses were
associated with ability to race following treatment.
Design—Multiple-center retrospective study.
Animals—25 Standardbreds and 20 Thoroughbreds.
Procedure—Medical records of horses with a primary
lung abscess that were admitted to any of 4 veterinary
teaching hospitals were reviewed. Results of
physical examination, laboratory testing, and thoracic
radiography were reviewed. Racing performance after
treatment was compared with performance before illness
and with performance of the general population
of racehorses of similar age, sex, and breed.
Results—23 of 25 Standardbreds and 13 of 20
Thoroughbreds raced after diagnosis and treatment of
a lung abscess. Most horses had a solitary abscess in
the dorsal to caudodorsal lung fields. Results of initial
physical examination, biochemical analyses, and culture
and identification of the microbial isolate were
not associated with whether a horse returned to racing.
For horses that had raced prior to the illness, race
performance after treatment of the lung abscess was
not significantly different from performance before
Conclusions and Clinical Relevance—On the basis
of racing performance in those horses that resumed
racing after treatment, long-term residual lung damage
did not develop in horses with primary lung
abscesses that were treated appropriately. It is not
known whether horses that recovered would be more
likely to bleed from the site of a prior infection when
resuming strenuous exercise and whether lung
abscesses contributed to a failure to resume racing.
(J Am Vet Med Assoc 2000;216:1282–1287)