First detection of sporocysts of Dicrocoelium, an important parasite in livestock, from the snail Aegista vulgivaga in the fields of Japan

Recently, the larvae of the trematode parasite Dicrocoelium were discovered in the field, for the first time in Japan. The results of this research were published in The Journal of Veterinary Medical Science on Saturday, July 10, 2021(Japan time). This research was conducted by Tsukasa Waki (Lecturer, Faculty of Science, Toho University), Yuma Ohari (Post-doctoral researcher, Hokkaido University), Kei Hayashi (Assistant professor, Okayama University of Science), Yasuhiro Takashima (Associate professor, Gifu University), Junji Moribe (Associate professor, Gifu University), and Kayoko Matsuo (Visiting veterinary professor, Aso Public Health Center, Kumamoto Prefecture). We interviewed Dr. Waki about this research, and we present a summary of it in the following section.

Key points

Dicrocoelium is an important parasite with respect to the livestock industry in Japan, but the route of infection for these domestic animals in the country has been unknown till date.
For the first time in Japan, the larvae of Dicrocoelium chinensis were found in the field; the specimens were isolated from Aegista vulgivaga that were collected from Gifu Prefecture.
Aegista vulgivaga is shown to harbor larvae of Dicrocoelium chinensis, thereby acting as a potential transmitter of the parasite.

Dr. Tsukasa Waki, Professor, Department of Environmental Science

Key Points

Dicrocoelium is an important parasite with respect to the livestock industry in Japan, but the route of infection for these domestic animals in the country has been unknown till date.
For the first time in Japan, the larvae of Dicrocoelium chinensis were found in the field; the specimens were isolated from Aegista vulgivaga that were collected from Gifu Prefecture.
Aegista vulgivaga is shown to harbor larvae of Dicrocoelium chinensis, thereby acting as a potential transmitter of the parasite.

Laeve of *D. chinensis* detected in gonad of *A. vulgivaga*

Summary
Dicrocoelium chinensis a is a significant parasite of domestic animals such as cattle. The parasitic larvae infect these animals, thereby affecting the livestock industry. This parasite has been described in various textbooks in Japan, but due to the lack of reports of Dicrocoelium sporocysts a in any wild Japanese land snails, the route of infection for the livestock has been unclear. Initially, it was thought that this worm is transmitted to livestock via ants from a snail species, Cochlicopa lubrica. However, a high percentage of wild animals such as the Japanese deer were infected with D. chinensis in spite of the rarity or absence of C. lubrica in those places.

In Gifu Prefecture, where C. lubrica is absent, various other snails were examined, and immature larvae of Dicrocoelium chinensis were found in Aegista vulgivaga. Dr. Waki says, “Dicrocoelium chinensis can be found in many places of Central Japan. If the presence of fully matured larvae is confirmed from the snail A. vulgivaga in future, we may be able to confirm that A. vulgivaga has a primary role in transmitting the infection to the domestic animals. We would like to continue our research.”

“Ants, pretending to be spears, hunting fireflies.”— This is a word game used by aspiring veterinarian students to remember the life history of a D. chinensis, specifically the fact that C. lubrica and ants can transmit the infection to the livestock. In this case, the word “firefly” refers to the C. lubrica, but this word game may change depending on the results of future research in this field.

READ FULL ARTICLE HERE