Scrub typhus ecology: a systematic review of Orientia in vectors and hosts

Parasites & Vectors

Table 2 Summary of total and median tested and O. tsutsugamushi positive for the three most frequently reported Leptotrombidium chigger species, subdivided into laboratory test categories

Laboratory method	Vector species name	Total no. tested	Median no. tested	Range	Total no. positive	Median no. positive/study site	Median positive (%)
Combination culture and molecular
	L. deliense	0^a	0	0	0	0	0
Pools	L. scutellare	10^b	10	10	8	4	40.0
	L. pallidum	?^b	?	?	3	3	–
Combination culture and serology
	L. deliense	?^b	?	?	3	3	–
Pools	L. deliense	?^b	?	?	2	2	–
	L. scutellare	10	10	10	4	4	40.0
Pools	L. scutellare	15	4	1–10	5	2.5	63.0
	L. pallidum	1811^b	66	23–734	75	12	18.0
Pools	L. pallidum	115^b	15	1–52	68	5	33.0
Combination culture +/− microscopy
	L. deliense	7^b	4	1–6	1	1	25.0
Pools	L. deliense	398^b	7	1–131	193	3	43.0
Pools	L. scutellare	183^b	24	11–148	5	1	4.2
	L. pallidum	17^b	8.5	1–16	8	4	47.0
Pools	L. pallidum	36^b	3	1–30	13	1	33.0
Serology
	L. deliense	1874	314	285–1275	51	4	13.0
Pools	L. deliense	665	333	5–660	18	9	27.0
	L. scutellare	1242	131	1–1110	6	3	2.3
	L. pallidum	1900	42	12–1263	202	10	24.0
Pools	L. pallidum	?^b	?	7–?	73	4	–
Molecular
	L. deliense	44	22	15–29	3	1.5	6.8
Pools	L. deliense	515	6	1–315	124	3	50.0
	L. scutellare	3053	54	11–1907	57	5	9.3
Pools	L. scutellare	127^b	4	1–105	35	1	25.0
	L. pallidum	1357	38	1–474	57	7	18.0
Pools	L. pallidum	4	2	1–3	0	0	0
Combined molecular and serology
Pools	L. deliense	42	42	42	25	25	60.0
	L. scutellare	2050	119	6–579	22	2	1.7
	L. pallidum	2735	80	1–1420	31	3	3.8

^aOne study reported 75% O. tsutsugamushi infection rate in pools made up of 20,700 L. deliense, but the number of pools tested and number positive were not reported [258]
^bIncludes studies where number of individuals/pools tested was not given (i.e. no denominator)
Key: +/−, with or without; ? unknown

ISSN: 1756-3305