An Aichi Medical University team visited Timor-Leste in Feb. 15 - May 15, 2006 (the first visit hereafter), and then in Nov. 20, 2006 - Feb. 15, 2007 (the second visit, by Dr. Takesue). The objectives were;

　

 As the schedule for MDA in each district had already been formulated, a field visit to each district was arranged before the planned MDA would start. However, 6 districts of Oecussi, Dili, Liquica, Manatuto, Viqueque and Manufahi had already been given a round of MDA before the present pre-treatment study started.

 For the survey, approximately 6,000 children at 35 pre-secondary schools (12-15 years of age in 3 grades) were selected from the whole country in 13 districts (Table 2). The number of samples in a district was largely proportional to the population size of each district. A WHO/Aichi Med. Univ. team visited a prearranged school, and, with assistance of teachers, selected randomly 43-73 students from each grade, or 128-220 in a school. They were requested to collect urine in a paper cup. Each sample was identified, added with preservative, and then transferred to Aichi Med. Univ. for measurement of urinary IgG4.

 In order to facilitate finding suitable sentinel sites for MDA monitoring, in the first visit, several villages were checked with Brugia Rapid test. The test, using whole blood samples, can give results (positive or negative) in 20 minutes. Unfortunately, we experienced technical problems in using whole blood. During the second visit, 8 villages were selected and the villagers (all adults) were examined by the same Brugia Rapid test, but, this time, plasma samples were used instead of whole blood samples. Urine samples from Brugia Rapid positive individuals can be a gold standard to determine the sensitivity of urine ELISA. Both Brugia Rapid test and urine ELISA detect filaria-specific IgG4. Until the sensitivity of urine ELISA will have been determined, all data presented in this report are tentative.

　

 Thirty-four pre-secondary schools out of the total 147 in the country were surveyed in the 2 visits. One school in Dili could not be visited. In the first visit, 3,461 students at 20 schools were examined for urinary IgG4 (Table 3a). There were 90 positives with the overall prevalence of 2.6%. The highest prevalence was observed at 2 schools in Covalima district (10.9% and 8.2%). Of 20 schools, only 4 showed 0%, indicating that filariasis is widespread. However, prevalence was relatively low in 9 schools having 0% < to 2%. The prevalence decreased gradually as the altitude of school location increased (Table 4). As B. timori is transmitted by Anopheles barbirostris, and this mosquito prefers to breed in clean water with particular affinity for irrigated rice fields, this may explain the tendency in part. Based on the results obtained in the first visit, a temporary distribution map of filariasis in Timor-Leste was made (Fig.1).

 In the second visit, urine samples were collected from 2,254 students in 14 schools. The samples are at moment being measured for IgG4 at Aichi Medical University (Table 3b).

　

 A total of 643 people in 8 villages were examined with Brugia Rapid tests. The overall prevalence was 23.9%, which was much higher than the school-based surveys. The reason for the high rate is that the village survey excluded children who have lower rate than adults. The highest prevalence was 43.8% in a south coast village, Luca, which was followed by Bibileo with 33.9% (Table 5). These two villages could be suitable sentinel sites to monitor the MDA program.

 The village survey resulted in 154 Brugia Rapid positive people and their urine samples can be a gold standard to determine the sensitivity of urine ELISA.

　

 We would like to thank Dr. Alex Andjaparidze, WHO Representative in Timor-Lesto for his support in literally all aspects of this cooperative project, including security matters that were most crucial. Salvador Amaral, WHO/Dili, was always with us in the fields, making otherwise tough field work easy and smooth. We would also thank Jose Baretto, WHO/Dili, and Antonio de Costa, Ministry of Health, for their contributions to this cooperative project. Megan Counahan and David Reeve of James Cook University, Australia, were kind advisors and coworkers in the field to collect samples.