To evaluate species identification and rabies virus (RABV) characterization among samples from bats submitted for rabies testing in the United States and assess whether a standardized approach to specimen selection for RABV characterization could enhance detection of a sentinel event in virus dissemination among bats.
United States public health rabies surveillance system data collected in January 2010 through December 2015.
The number of rabies-tested bats for which species was reported and the number of RABV-positive samples for which virus characterization would likely provide information regarding introduction of novel RABV variants and translocation and host-shift events were calculated. These specimens were designated as specimens of epizootiological importance (SEIs). Additionally, the estimated test load that public health laboratories could expect if all SEIs underwent RABV characterization was determined.
Species was reported for 74,928 of 160,017 (47%) bats submitted for rabies testing. Identified SEIs were grouped in 3 subcategories, namely nonindigenous bats; bats in southern border states, Florida, Puerto Rico, and the US Virgin Islands; and bats of species that are not commonly found to be inflected with RABV. Annually, 692 (95% CI, 600 to 784) SEIs were identified, of which only 295 (95% CI, 148 to 442) underwent virus characterization. Virus characterization of all SEIs would be expected to increase public health laboratories’ overall test load by 397 (95% CI, 287 to 506) samples each year.
CONCLUSIONS AND CLINICAL RELEVANCE
Species identification and RABV characterization may aid detection of a sentinel event in bat RABV dissemination. With additional resources, RABV characterization of all SEIs as a standardized approach to testing could contribute to knowledge of circulating bat RABV variants.
Objective—To estimate the number of dogs required
to find linkage to heritable traits of hip dysplasia in
dogs from an experimental pedigree.
Animals—147 Labrador Retrievers, Greyhounds, and
their crossbreed offspring.
Procedure—Labrador Retrievers with hip dysplasia
were crossed with unaffected Greyhounds. Age at
detection of femoral capital ossification, distraction
index (DI), hip joint dorsolateral subluxation (DLS) score,
and hip joint osteoarthritis (OA) were recorded. Power
to find linkage of a single marker to a quantitative trait
locus (QTL) controlling 100% of the variation in a dysplastic
trait in the backcross dogs was determined.
Results—For the DI at the observed effect size,
recombination fraction of 0.05, and heterozygosity of
0.75, 35 dogs in the backcross of the F1 to the
Greyhound generation would yield linkage at a power
of 0.8. For the DLS score, 35 dogs in the backcross to
the Labrador Retriever generation would be required
for linkage at the same power. For OSS, 45 dogs in
the backcross to the founding Labrador Retrievers
would yield linkage at the same power. Fewer dogs
were projected to be necessary to find linkage to hip
OA. Testing for linkage to the DLS at 4 loci simultaneously,
each controlling 25% of the phenotypic variation,
yielded an overall power of 0.7.
Conclusions and Clinical Significance—Based on
this conservative single-marker estimate, this pedigree
has the requisite power to find microsatellites
linked to susceptibility loci for hip dysplasia and hip
OA by breeding a reasonable number of backcross
dogs. (Am J Vet Res 2003;222:418–424)
Objective—To determine the genetic influence on
expression of traits associated with canine hip dysplasia.
Animals—193 dogs from an experimental canine
Procedure—An experimental canine pedigree was
developed for linkage analysis of hip dysplasia by mating
dysplastic Labrador Retrievers with nondysplastic
Greyhounds. A statistical model was designed to test
the effects of Labrador Retriever and Greyhound alleles
on age at detection of femoral capital epiphyseal
ossification, 8-month distraction index, and 8-month
dorsolateral subluxation score.
Results—The additive effect was significant for age
at detection of femoral capital epiphyseal ossification.
Restricted maximum likelihood estimates (± SD)
for this trait were 6.4 ± 1.95, 10.2 ± 2.0, 10.8 ± 3.1,
11.4 ± 2.1, and 13.6 ± 4.6 days of age for
Greyhounds, Greyhound backcross dogs, F1 dogs,
Labrador Retriever backcross dogs, and Labrador
Retrievers, respectively. The additive effect was also
significant for the distraction index. Estimates for this
trait were 0.21 ± 0.07, 0.29 ± 0.15, 0.44 ± 0.12, 0.52
± 0.18, and 0.6 ± 0.17 for the same groups, respectively.
For the dorsolateral subluxation score, additive
and dominance effects were significant. Estimates
for this trait were 73.5 ± 4.1, 71.3 ± 6.5, 69.1 ± 6.0,
50.6 ± 12.9, and 48.4 ± 7.7%, respectively, for the
Conclusions—In this canine pedigree, traits associated
with canine hip dysplasia are heritable. Phenotypic
differences exist among founder dogs of each breed
and their crosses. This pedigree should be useful for
identification of quantitative trait loci underlying the
dysplastic phenotype. (Am J Vet Res 2002;63: