RESUMO
Objective@#To understand the situation and genotype distribution of spotted fever group rickettsia (SFGR) in the border area of Tumen River Basin in free ticks in Yanbian Korean Autonomous Prefecture (Yanbian Prefecture), Jilin Province. @*Methods@#From April to September, 2017, ticks were collected using flagging method from Hunchun, Tumen, Helong and Longjing cities in the Tumen River basin of Yanbian Prefecture. Outer membrane protein A (ompA) was detected by Polymerase Chain Reaction (PCR), then, the species were identified by gene sequencing and analyzed systematically. The positive rate of pools and MIR(minimum infection rate per 100 ticks,MIR) of SFGR were calculated, and the difference of positive rate of pools among ticks with different characteristics was compared by Chi-square test. @*Results@#A total of 3 079 ticks were collected and divided into 536 pools. The positive rate of pools of SFGR nucleic acid was 39.7% (213 pools). The MIR of SFGR was 6.9%.The positive rate of pools of SFGR in Dermacentor silvarum, Haemaphysalis concinna, Haemaphysalis japonica, Haemaphysalis longicornis and Ixodes persulcatus were 80.4% (41/51), 14.0% (25/179), 20.2% (18/89), 78.9% (101/128) and 25.9% (21/81), and the difference was statistically significant (P<0.001). There was statistical difference in the positive rate of pools of SFGR in developmental stages of ticks (P<0.001); the positive rate of pools of female adults, male adults, nymph and larvae were 36.4% (95/261), 34.2% (67/196), 56.3% (40/71) and 7/8, and the MIR was 7.9%, 7.7%, 4.9% and 3.5%. The five genotype was detected which was Candidatus Rickettsia longicornii, Rickettsia raoultii, Rickettsia heilongjiangensis, Candidatus Rickettsia tarasevichiae,Rickettsia monacensis and have 98%-100% homology with known gene sequences. Candidatus Rickettsia longicornii, Rickettsia raoultii, Rickettsia heilongjiangensis and Candidatus Rickettsia tarasevichiae showed close evolutionary relationship with known specie (have 98%-100% homology with known gene sequences); Rickettsia monacensis showed Far from evolutionary relationship with known species (have 98% homology with known gene sequences). @*Conclusion@#SFGR infection of ticks is common in the border areas of the Tumen River Basin. There was high diversity in SFGR species and tick species in the areas surveyed.
RESUMO
OBJECTIVE: This study aimed at finding epidemiological and clinical features of autochthonous Lyme borreliosis in humans through epidemiological investigations and identifying its vectors and pathogens through analysis of ticks. METHOD: Epidemiological investigations, including review of the retrospective medical records and patient interviews, were conducted in two cases that occurred in 2012. To identify the vectors and pathogens, ticks were collected between September 23 and October 6, 2012 from the area where the tick bite in the first patient occurred. The ticks were classified, and polymerase chain reaction (PCR) tests and cultures were performed. RESULTS: The first patient, a 46-year-old female, visited a forest in Gangwon province, which was 900 m above sea level, where the tick bite occurred. Two weeks after the tick bite, erythema migrans (12 × 6 cm(2) in size) appeared on the site of tick bite, along with fever, chill, fatigue, myalgia, and arthralgia on shoulders, knees, and hips. The second patient, a 44-year-old male, visited a mountain in Gangwon province, which was 1200 m above sea level, where a tick bite occurred. One month after the tick bite, erythema migrans appeared at the site of the tick bite, along with fatigue, myalgia, and arthralgia on the right shoulder and temporomandibular joint. Indirect fluorescent antibody testing and Western blotting were carried out in these two cases for diagnosis, and positive findings were obtained. As a result, Lyme borreliosis could be confirmed. To estimate the pathogens and vectors, the ticks were collected. A total of 122 ticks were collected and only two species, Haemaphysalis japonica and Haemaphysalis flava, were identified. PCR and culture were performed on ticks. However, Borrelia burgdo rferi sensu lato was not isolated from any collected ticks. CONCLUSIONS: This study is significant to confirm Lyme borreliosis officially at first by the national surveillance system, although identification of the mites and pathogens failed.
