Bayer and Kyowa Hakko will begin sales on March 9, 2000 of an oral ectoparasiticide that disinfests the Benedenia seriolae (common name, hada mushi) that live on the body surface of fish belonging to the order Percomorphi. The product will be sold under the trade name "Hada Clean" by Bayer and "Suisanyo Benesal" by Kyowa Hakko, respectively.

Praziquantel (isoquinoline pyrazine derivatives), the product's principal ingredient, was developed by Bayer and is marketed worldwide as a medicine for human and animals. To extend its efficacy to parasitical disease in fish, Bayer commenced a joint research project in 1996 with Kyowa Hakko, a company noted for its significant presence in the Japanese aquaculture market. Approval for aquacultural applications was obtained on February 24, 2000. This product, the first orally administered ectoparasiticide for aquacultural use in Japan, demonstrates a superior ability to disinfest hada mushi among fish in the order Percomorphi (yellowtail, etc.). Bayer will import the active ingredient, and both companies will engage in their own manufacturing operations.

Hada mushi is a parasite that belong to the subfamily, Monogenean benedenia. Adhering firmly to the body surfaces of fish, it intakes epithelial cells, mucus, etc., and grow to a length of approximately 14 millimeters. On fish that have become hosts to hada mushi, the infested part ulcerates, and bleeding occasionally occurs. Moreover, symptoms can worsen as the fish rub their bodies against enclosure nets, which increases the chances for bacterial infection in the infested parts. Consequently, damage frequently becomes extensive.

Fish farmers have conventionally dealt with hada mushi by placing fish for short periods in sheet-tanks filled with fresh water or preparations of hydrogen peroxide water. But because of the large amounts of labor required to move the fish and the great stress placed on the fish during this procedure, fish farmers have earnestly hoped for the development of an orally administered medication to treat benedeniosis.

"Hada Clean" and "Suisanyo Benesal" are administered by mixing with cultured fish feed. In this form, the medication moves quickly through the body of the fish to the epidermis, where it acts on the hada mushi living on the body surface and disinfests the parasite. Because it is orally administered, this product is easy to handle and its effectiveness in controlling parasite is extremely high. Other benefits of oral administration include the minimizing of stress placed on fish, and the opportunity to sharply reduce labor requirements.

1. Product names	"Hada Clean" (Bayer) "Suisanyo Benesal" (Kyowa Hakko)
2. General name	Praziquantel (isoquinoline pyrazine derivatives)
3. Efficacy	Disinfests parasitical hada mushi living on the body surface of fish in the order Percomorphi
4. Special characteristics	(1) Extremely high efficacy (2) Ease of handling due to oral administration (3) Minimal stress caused on fish (4) Major reductions in the labor required for controlling hada mushi (5) Quick movement of the active ingredient into mucus on body surface after oral adminsitration

Bayer Group in Japan
Established: 1911
Location of parent company: Minato-ku, Tokyo (corporate headquarters)
Senior representative: Knut Kleedehn
Number of employees: 2,973
Sales: ¥223.0 billion (1998)
Business activities: The import, manufacturing and marketing of health care products, agriculture-related products, polymers, and chemicals.


Kyowa Hakko Kogyo Co., Ltd.
Established: 1949
Location of parent company: 6-1, Otemachi 1-chome, Chiyoda-ku, Tokyo
President: Tadashi Hirata
Number of employees: 5,044 (as of the end of March 1999)
Sales: ¥323.2 billion (April 1998 - March 1999)
Business activities: Primarily, the manufacturing and marketing of pharmaceutical products; also the production and marketing of alcoholic beverages, foods, chemicals and biochemical-related products.