Five years of post-validation surveillance of lymphatic filariasis in Thailand

Table 1 Results of human blood surveys in 11 provinces: PVS 2018–2022

Province (total No. of IUs)	Year^a	No. of IUs surveyed	Population in surveyed IUs	No. tested with FTS	No. of Ag+ cases	No. tested with TBF	No. of Mf+ cases	AGR (%)	Cumulative Mf rate (%) and [range]	Population coverage in surveyed IUs (%)
Mae Hong Son (76)	2019	8	1143	909	0	0	0	0	0	79.52
	2021	8	1895	1411	0	0	0	0	0	74.45
	2022	9	1763	1159	0	0	0	0	0	65.74
Chiang Mai (2)	2021	1	250	236	0	0	0	0	0	94.40
	2022	2	211	211	0	0	0	0	0	100.00
Tak (124)	2018	11	2587	0	0	1852	0	0	0	71.58
	2019	18	4878	4461	0	0	0	0	0	91.45
	2020	12	4144	3128	0	0	0	0	0	75.48
Kanchanaburi (49)	2019	5	3411	3063	0	0	0	0	0	89.79
	2020	3	1395	1275	0	0	0	0	0	91.39
	2021	6	1409	1305	3	0	0	1.25	0	92.61
	2022	5	1931	1657	0	0	0	0	0	85.81
Lamphun (3)	2022	1	238	238	0	0	0	0	0	100.00
Ratchaburi (4)	2019	1	993	824	0	0	0	0	0	82.98
	2020	2	522	483	0	0	0	0	0	92.52
Ranong (2)	2020	1	1692	510	0	0	0	0	0	30.14
	2021	1	1458	1080	0	0	0	0	0	74.07
	2022	1	352	300	0	52	0	0	0	100.00
Krabi (2)	2019	1	799	0	0	193	0	0	0	24.15
	2020	1	131	0	0	131	0	0	0	100.00
Nakhon Si Thammarat (2)	2018	1	1388	0	0	530	0	0	0	38.18
	2020	2	917	0	0	372	0	0	0	40.56
	2021	1	132	0	0	132	0	0	0	100.00
Surat (6)	2018	1	502	0	0	487	0	0	0	97.01
	2020	2	845	0	0	666	0	0	0	78.81
	2021	1	116	116	0	0	0	0	0	100.00
	2022	1	102	102	0	0	0	0	0	100.00
Narathiwat (87)	2018	9	6115	0	0	4911	9	0	0.18 [0–0.77]	80.31
	2019	10	6847	0	0	6284	8	0	0.12 [0–3.03]^b	91.77
	2020	8	5200	0	0	3791	4	0	0.10 [0–0.45]	72.90
	2021	8	4819	0	0	3989	1	0	0.02 [0–0.42]	82.77
	2022	11	5292	0	0	4351	2	0	0.04 [0–0.53]	82.21

Mf+ microfilaria positive, AGR antigen rate, IU implementation unit, FTS Filaria antigen test strip, TBF Thick blood film, PVS Post-validation surveillance
^aOnly years where surveys were conducted are tabled. No surveys were conducted in years not shown
^b Mf rate of 3.03 was recorded in Paye IU with 2 positive cases among 66 persons tested by TBF

ISSN: 2049-9957