Introduction Neosporosis is a disease caused by the obligate
intracellular apicomplexan parasite Neospora caninum that can cause fatal
multisystemic infections in dogs. Antemortem diagnosis can be difficult and false
negatives may lead to inappropriate treatments and poor outcome. Here we describe
an
ISH protocol for muscle biopsies.
Material and Methods Muscle biopsies of 12 cases with confirmed N.
caninum infection were retrospectively evaluated with ISH. Two chromogenic
labeled probes targeting the 18S and the 28S ribosomal RNA (rRNA) of N.
caninum were designed and different protocols were tested and evaluated.
Immunohistochemistry (IHC) was used for comparison.
Results ISH was able to detect N. caninum in 8/12
cases. In 3/12 no positive signal could be identified and in one case
results were considered inconclusive. IHC revealed intralesional parasites in
6/12 cases.
Conclusion To the best of our knowledge, ISH has never been used in
diagnostic settings on canine muscle biopsies for detection of N. caninum.
Apart from identification of parasitic cysts, our protocol was also able to identify
bradyzoites from ruptured cysts. Overall, we could increase the sensitivity of
microscopic parasitic identification with direct impact on patient management.
