Figure 1Monthly distribution for the field ticks collected in South Korea, from May 2014-April 2018.
Figure 2Phylogenetic tree based on 16S rRNA gene sequence of Rickettsia species detected in the field ticks collected in South Korea, from May 2014-April 2018. The phylogenetic tree was constructed through the neighbor-joining method with the Kimura two-parameter model (bootstrap 1,000) using MEGA 6.0. The GenBank accession numbers of each sequence of Rickettsia species and Anaplasma species are indicated.
Figure 3Phylogenetic tree based on 16S rRNA gene sequence of Anaplasma species detected in the field ticks collected in South Korea, from May 2014-April 2018. The phylogenetic tree was constructed through the neighbor-joining method with the Kimura two-parameter model (bootstrap 1,000) using MEGA 6.0. The GenBank accession numbers of each sequence of Anaplasma phagocytopylum and Ehrlichia species are indicated.
Figure 4Phylogenetic tree based on the Fla gene sequence of Borrelia species detected in the field ticks collected in South Korea, from May 2014-April 2018. The phylogenetic tree was conducted through the neighbor-joining method with the Kimura two-parameter model (bootstrap 1,000) using MEGA 6.0. GenBank accession numbers of Borrelia species are indicated for each sequence
Table 1Seasonal variation of species detected in field ticks collected in the Gwang-ju metropolitan area, South Korea (May 2014–April 2018).
Duration |
Tick (pools) |
Hamaphysalis longicornis
|
Hamaphysalis flava
|
Ixodes nipponensis
|
Amblyomma testudinarium
|
11,717 (1,094) |
10,904 (93.1%) |
656 (5.6%) |
151 (1.3%) |
6 (0.05%) |
May-December 2014 |
1,824 (179) |
1,761 |
41 |
22 |
0 |
2015 |
2,849 (297) |
2,578 |
240 |
29 |
2 |
2016 |
3,172 (308) |
2,895 |
237 |
39 |
1 |
2017 |
3,079 (238) |
2,940 |
99 |
39 |
1 |
January-April 2018 |
793 (72) |
790 |
39 |
22 |
2 |
Table 2Prevalence [minimum positive rate (%)] of pathogens (pools) in the field ticks collected in the Gwang-ju metropolitan area, South Korea (May 2014–April 2018).
|
Total |
Hamaphysalis longicornis
|
Hamaphysalis flava
|
Ixodes nipponensis
|
Amblyomma testudinarium
|
Collected field ticks |
11,717 |
10,904 |
656 |
151 |
6 |
|
Pools |
(1,094p) |
(640p) |
(321p) |
(127p) |
(6p) |
|
Detected pathogen (pool) |
57 |
35 |
4 |
16 |
- |
|
Rickettsia species
|
45 (0.38) |
31 (0.28) |
5 (0.76) |
9 (5.96) |
- |
Anaplasma phagocytopylum
|
3 (0.02) |
2 (0.02) |
- |
1 (0.66) |
- |
Borrelia species
|
9 (0.07) |
2 (< 0.01) |
1 (0.15) |
6 (3.97) |
- |
Table 3A cross-sectional study of seasonal factors and tick species using logistic regression analysis of Rickettsia species in field ticks collected in the Gwang-ju metropolitan area, South Korea (May 2014 - April 2018).
Factors |
Tick (test pools) |
Positive pools (MPR, %) |
p
|
OR |
95% CI |
Season |
11,717 (1,094) |
45 (0.38) |
|
|
|
|
Spring (March-May) |
4,021 (341) |
13 (0.32) |
0.166 |
0.236 |
0.030–1.824 |
Summer (June-August) |
3,303 (290) |
14 (0.42) |
0.104 |
0.184 |
0.024–1.418 |
Autumn (September-November) |
4,193 (355) |
17 (0.40) |
0.118 |
0.198 |
0.026–1.511 |
Winter* (December-February) |
200 (108) |
1 (0.5) |
- |
- |
- |
|
Species of ticks |
11,717 (1,094) |
45 (0.38) |
|
|
|
|
Haemaphysalis longicornis
|
10,904 (640) |
31 (0.28) |
0.302 |
1.498 |
0.695–3.229 |
Haemaphysalis. flava
|
656 (321) |
5 (0.76) |
0.006 |
4.820 |
1.583–14.678 |
Ixodes nipponensis*
|
151 (127) |
9 (5.96) |
- |
- |
- |
Amblyomma testudinarium
|
6 (6) |
0 (0.0) |
- |
- |
- |