In accordance with the Japan-Lao Medical Cooperation Program for the Control of Schistosomiasis in South Laos, Sasakawa Memorial Health Foundation dispatches us, Professor Kazuo Yasuraoka, Profeddor Hajime Matsuda, and Dr. Masashi Kirinoki to Laos for the period 25 April - 13 May 1995 to collaborate with the Deprtment of Health, Institute of Malariology, Parasitology and Entomology(IMPE) and the local staff involved in schistosomiasis control in South Laos. Taking this opportunity, sincere appreciation is expressed to you for your kind arrangements to have our passports visaed.
We arrived at Khong on 30 April. Malacological and seroepidemiological surveys were conducted along the Mekong River from Khong up to the north of Pakxe. All the operations were performed in excellent cooperation with Dr. Rattanaxay Phetsouvanh and Mr. Bourley Keokhamphavanh, IMPE, Dr.Vath Khongkeo and Messrs. Kamphan and Bounthavi, Champasack Province Health Office, as well as the technical staff of the District Health Offices involved.
Malacological surveys
When the malacological surveys commenced at Khong on 30 April, the circumstances contrasted with the previous visit in low water periods in April-May 1991. Green algae or duck weeds have grown extensively along the shore of Khong Town due to unusual low water this year. The search for snails in Khong was therefore accomplished in shallow water with a detectable curent, 100 to 200 meters off the shore. In this survey, sanils were collected by lifting submerged stones and taking them by toothbrushes from the stones to which they adhered. Snail population density was
expressed as the number of snails per 100 square cm on a stone, by counting all snails on stones collected. It was reconfirmed that the gamma Neotricula aperta extremely predominated in the (hong District(Table 1).
