Objective To investigate the difference in the positive rate of Orientia tsutsugamushi between different organs of small mammals, and to provide a reference for the pathogen monitoring of scrub typhus. Methods Liver, spleen, lung, kidney, and ear samples were collected from 105 small mammals collected in Yongcheng city of Henan province, China in October 2017, and liver, spleen, and ear samples were collected from 324 small mammals collected in Pinggu district of Beijing, China from September to November 2018. DNA was extracted, and nested PCR amplification was used to detect the nucleic acid fragment of the 56 kDa protein gene of O. tsutsugamushi. The specimens with specific bands were genotyped by comparison of nucleotide sequence, and the positive rate was calculated. Results The positive rate of O. tsutsugamushi in small mammals was 10.48% in Yongcheng city and 12.96% in Pinggu district, with no significant difference (χ2=0.494, P=0.504). The positive rate of O. tsutsugamushi in different organs within the same site was 0.98%-14.81%; pairwise comparison showed that the positive rate of O. tsutsugamushi in the ear of the small mammals in Yongcheng city was higher than that in the other four organs, and the positive rate of O. tsutsugamushi in the liver of the small animals in Pinggu district was significantly higher than that in the spleen (χ2=5.818, P=0.022). The comparison of the two places showed that the positive rate of O. tsutsugamushi in the ear of the small mammals in Yongcheng city was significantly higher than that in Pinggu district (χ2=6.525, P=0.011). For the small mammals in Pinggu district, the positive rate of Shimokoshi-type O. tsutsugamushi in the spleen was lower than that in liver and the ear, while there was no significant difference in the positive rate of Kawasaki-type O. tsutsugamushi between the different organs (χ2=1.560, P=0.455). The pooled analysis of the detection results of the liver and the spleen in Yongcheng city and Pinggu district showed that the positive rate of O. tsutsugamushi in the liver was higher than that in the spleen. The results of consistency test showed no significant difference (Kappa=0.015, P=0.744), with poor consistency of positive infection in the liver and the spleen. Conclusion There are no significant differences in the positive rates of Kawasaki-type O. tsutsugamushi in the liver, spleen, lung, and kidney of small mammals between Yongcheng city and Pinggu district, while the positive rate of Shimokoshi-type O. tsutsugamushi in the liver and the ear is higher than that in the spleen. Detection of O. tsutsugamushi in the organ of various small mammals or in multiple organs can improve the detection rate of O. tsutsugamushi, and rodent ears can also be used as samples for the pathogen monitoring of scrub typhus.
ZHAO Jia-xin, WANG Yu-jiao, LI Yong-xiang, MU Qun-zheng, XIA Qing, SONG Xiu-ping, LI Dong-mei, LU Liang, LI Gui-chang
. Positive rate of Orientia tsutsugamushi in different organs of small mammals[J]. Chinese Journal of Vector Biology and Control, 2021
, 32(4)
: 428
-431
.
DOI: 10.11853/j.issn.1003.8280.2021.04.008
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