Cryptococcosis is an important systemic mycosis caused by members of the Cryptococcus neoformans species complex. This disease is potentially fatal in various animals, including koalas. We describe the long-term surveillance and treatment of subclinical cryptococcosis and nasal colonization of koalas by Cryptococcus neoformans and C. gattii. Of the 15 animals investigated through the use of samples obtained by nasal swabs, antigen titer measurements, and pathologic examination, C. neoformans was found associated with nine koalas and C. gattii with one animal. Nine koalas showed subclinical disease and one clinical infections and antigenemia. Treatment with fluconazole, itraconazole and amphotericin B upon detection of C. neoformans or C. gattii was not effective. The results of the present study showed that C. neoformans was the predominant species isolated from the nasal swab samples and the fungus might have naturally become associated with the koalas' nasal cavities at Kanazawa Zoological Gardens. The unclear treatment effectiveness might have been caused by a shorter treatment period that is routinely used and unstable itraconazole absorption. This investigation also underscores the need for identifying effective treatment regimens for subclinical cryptococcosis and efficient measures for eradicating C. neoformans and C. gattii in koalas.

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Sarcoptes scabiei is one of the important external parasites. Although ivermectin is the recommended treatment, many raccoon dogs (Nyctereutes procyonoides) that were rescued and brought to the Kanazawa Zoological Gardens (Yokohama, Japan) have died because of S. scabiei, even after receiving single ivermectin treatment. Therefore, supportive treatment should be required. The present study revealed the number of animals that survived was greater after the administration of ivermectin along with an antibiotic for all raccoon dogs, as well as following the administration of fluid therapy to the debilitated raccoon dogs infected with S. scabiei, immediately after the rescue. During the initial period, treatment to improve the general clinical condition was required prior to deworming treatment for S. scabiei.

ABSTRACT. The prevalence of Dirofilaria immitis in free-ranging raccoon dogs (Nyctereutes procyonoides viverrinus) was examined in the southeast region of Kanagawa Prefecture, Japan, using a rapid immunomigration (RIM) test kit. Between April 2007 and March 2010, we examined 108 raccoon dogs rescued and housed by the Kanazawa Zoological Garden. D. immitis infection was found in 8 (7.4%) raccoon dogs. This is the first report to reveal the prevalence of D. immitis infection in living raccoon dogs. The prevalence of the infection was lower than previously reported values obtained on postmortem examination. One reason might be that the present study included young raccoon dogs infected with immature worms. Significant high-risk areas of D. immitis infection in the raccoon dogs were not observed.