SEASONAL VARIATION IN THE TEMPERATURE-EXTRUDING RESPONSE RELATION OF ONCOMELANIA NOSOPHORA, THE VECTOR SNAIL OF SCHISTOSOMA JAPONICUM IN JAPAN

• Published in: Japanese Journal of Medical Science and Biology Vol. 14; no. 4; pp. 195 - 200
• Main Author: YASURAOKA, KAZUO
• Format: Journal Article
• Language: English
• Published: National Institute of Infectious Diseases, Japanese Journal of Infectious Diseases Editorial Committee 1961
• ISSN: 0021-5112; 1884-2828
• DOI: 10.7883/yoken1952.14.195

Oncomelania nosophora, the vector snail of Schistosoma japonicum in Japan, has an amphibious habit. These snails are usually found on the moist soil just above the water edge of the brook or on moist vegetable matter above the level of water. If the habitat is changed into unfavorable condition such as the dryness, the cold or the heat, they shut themselves up into the shells. When the snails were submerged in water at room temperature, they open their opercula and extrude out the feet and the heads, from the shell. There are several factors which influence the mode of the response. Among them, temperature appears to be the most important one. As has already been pointed out by McMullen (1952), apparent limitations of molluscicides against Oncomelania snails, imposed by environmental conditions, have prompted increased emphasis on fundamental studies of snail biology. Although it has been found that temperature affects the biological process of the snails and molluscicidal activity against the snails, very little is known concerning the seasonal variation in the response of snails to temperature. Therefore, the study herein reported was conducted to know the seasonal variation and experimental acclimatization in the temperature-extruding response of O. nosophora.