Table 2. Space-time clusters of DF transmission in the Asia-Pacific region, 1955–2004.

Cluster	Countries	Radius (km)	Time frame	No. Obs.	No. Exp.	Relative risk	LLR*
1955–1964
1†	Thailand	0	1960/1/1 to 1964/12/31	18337	527.21	96.13	54814.34
2	Philippines	0	1960/1/1 to 1964/12/31	3092	571.13	5.95	2819.03
1965–1974
1†	Singapore, Malaysia,Thailand, Vietnam	1711.16	1971/1/1 to 1974/12/31	76393	6143.11	24.05	142940.013
2	Philippines	0	1966/1/1 to 1966/12/31	9384	528.09	18.88	18411.19
3	Myanmar	847.81	1974/1/1 to 1974/12/31	2477	1755.02	1.42	133.25
1975–1984
1†	Vietnam, Laos, Thailand	812.13	1980/1/1 to 1984/12/31	510942	38105.18	31.06	1024627.77
2	Cook Islands	0	1980/1/1 to 1980/12/31	357	1.31	273.01	1646.82
3	Malaysia	0	1982/1/1 to 1982/12/31	3052	1114.03	2.75	1140.04
4	Indonesia	0	1983/1/1 to 1984/12/31	26585	23294.07	1.15	228.63
1985–1994
1†	Vietnam, Laos, Thailand	812.13	1987/1/1 to 1991/12/31	1034416	79277	27.18	2009818.49
2	Cook Islands	0	1991/1/1 to 1991/12/31	1776	2.54	699.17	9858.32
3	Indonesia	0	1988/1/1 to 1988/12/31	44573	23048	1.96	7995.79
4	Maldives	0	1988/1/1 to 1988/12/31	2054	30.41	67.61	6630.25
5	Philippines	0	1991/1/1 to 1991/12/31	11317	8290	1.37	497.68
1995–2004
1†	Singapore, Malaysia,Thailand, Vietnam, Laos	1872.04	1995/1/1 to 1998/12/31	852301	95356.45	13.02	1243215.57
2	Philippines	0	2001/1/1 to 2004/12/31	94651	45564.40	2.12	21013.62
3	Sri Lanka, Maldives	983.29	2002/1/1 to 2004/12/31	29895	8771.22	3.44	15623.32

No. Obs, number of observed cases; No. Exp, number of expected cases; LLR, Log -likelihood Ratio.

*P<0.05;

^†Most likely cluster.