Yohei Matoba

Molecular evidence for the presence of new Babesia species in feral raccoons (Procyon lotor) in Hokkaido, Japan.

We recently reported that feral raccoons (Procyon lotor) with splenomegaly native to Japan were carriers of a Babesia microti-like parasite identical to that found in the United States, which was likely introduced to Japan from North America via raccoons imported as pets. Thus, we attempted extensive molecular survey for piroplasma infections of feral raccoon with normal spleen in Hokkaido, Japan using nested PCR that target broadly to 18S ribosomal RNA gene (SSU-rDNA) of all the parasites in the genus Babesia, Theileria, Cytauxzoon and B. microti group. Of the 348 raccoon samples analyzed, 9 gave positive signals. Cloning and phylogenetic analysis on SSU-rDNA sequences revealed that six of nine positives were found to be infected with Babesia and the remaining three with previously unreported Sarcocystis. Babesia sequences were further separated into two distantly related groups, those that reside in a novel phylogenetic group were consisted solely of four parasites found in this study, while those which included one identical sequence found in the three of our specimens were assembled together with both Babesia parasites of ticks in Japan and of raccoons in U.S. These results may indicate that not only a B. microti-like parasite but also at least two yet undescribed Babesia species are being established in their new life cycles in the feral raccoon populations in Japan.

Parasitic helminths from feral raccoons (Procyon lotor) in Japan

SummaryAn epidemiological survey of 1688 free-ranging raccoons (Procyon lotor) captured on the Japanese main islands of Hokkaido, Honshu and Kyushu was undertaken to determine whether Baylisascaris procyonis, which provokes fatal neurological larva migrans was present; however, the worm was not detected in any of these individuals. A helminthological investigation was carried out on 229 of the captured racoons and the following worms obtained: Toxocara tanuki, Porrocaecum sp., Molineus legerae, Ancylostoma kushimaense, Aonchotheca putorii, Centrorhynchus sp., Centrorhynchus bazaleticus, C. elongatum, Plagiorhynchidae gen sp., Hemiechinosoma sp., Metagonimus takahashii, M. miyatai, Euparyphium sp., Plagiorchis muris, Brachylaima sp., and Taenia hydatigena. These were the first records of Porrocaecum sp., M. miyatai, Brachylaima sp. and T. hydatigena obtained from Japanese feral raccoons. Scanning electron microscopic and/or molecular analyses were performed for both T. tanuki and T. hydatigena as these helminths both have a zoonotic counterpart amongst their families.

Epidemiology, histpathology, and muscle distribution of Trichinella T9 in feral raccoons (Procyon lotor) and wildlife of Japan

The prevalences of Trichinella T9 in trapped raccoons (Procyon lotor) and several other potential mammalian reservoirs in Hokkaido, Wakayama, and Nagasaki Prefectures were investigated. Muscle samples were collected from 2003 to 2006 from 1,080 raccoons, 113 raccoon dogs including 2 species (Nyctereutes procyonoides albus and N. p. viverrinus), 41 wild boars (Sus scrofa leucomystax), 14 martens (Martes melampus), 10 badgers (Meles meles), 5 Siberian weasels (Martes sibirica coreana), 7 mink (Mustela vison), and 1 red fox (Vulpes vulpes japonica). The samples were digested, and the prevalence and mean intensity of infection with the Trichinella muscle larvae were determined. The prevalence and intensity of the muscle larvae were 0.9% and 93.3 larvae/g (range 0.4–201.8) in raccoons, and 1.6% and 61.6 larvae/g in raccoon dogs, respectively. The infected animals were captured in different areas in Hokkaido Prefecture. These results confirmed that raccoons, which have been introduced from North America since the 1970s, are involved in the sylvatic cycle of Trichinella in Japan. In raccoons, the muscle density of Trichinella T9 larvae was highest in the tongue, and larvae were not found in the heart muscle or diaphragm. This is the first report of Trichinella T9 infection of feral raccoons in Japan.