1.A new record of Rickettsia japonica in ticks infesting a Burmese ferret-badger in Thailand
Hirunkanokpun, S. ; Ahantarig, A. ; Baimai, V. ; Pramual, P. ; Trinachartvanit, W.
Tropical Biomedicine 2022;39(No.1):55-59
Ticks are important vectors of arthropod-borne diseases and they can transmit a wide variety
of zoonotic pathogens to humans, domestic and wild animals. Rickettsia japonica is a member
of SFG rickettsiae causing Japanese spotted fever (JSF) and can transmit to humans via
infected ticks. In this study, we report the first case of Rickettsia japonica in Haemaphysalis
hystricis tick collected from a roadkill Burmese ferret-badger (Melogale personata) in Loei
province, northeastern Thailand. According to the DNA sequences and phylogenetic analyses
of the outer membrane protein A and B genes (ompA and ompB), the detected R. japonica
was identical to those found in JSF patients in Korea, Japan, and China, and closely related
to Rickettsia detected by ompA in a tick from Thailand. Further study on the prevalence of
R. japonica and diversity of mammalian reservoir hosts will be useful to gain a better
understanding of JSF epidemiology.
2.Coxiella-like bacteria in Haemaphysalis wellingtoni ticks associated with Great Hornbill, Buceros bicornis
Usananan, P. ; Kaenkan, W. ; Trinachartvanit, W. ; Baimai, V. ; Ahantarig, A.
Tropical Biomedicine 2022;39(No.2):191-196
Birds are known to be the most mobile hosts and are therefore considered to be hosts with potential
to contribute to the long-distance spread and transmission of tick-borne pathogens. In the present
study, ticks were collected from a hornbill nest at Chaiyaphum Province, Thailand. They were screened
for the presence of Coxiella bacteria using conventional PCR. The evolutionary relationships of positive
Coxiella-like bacteria (CLB) were analysed based on the gene sequences of 16S rRNA, groEL and rpoB.
Among all 22 tested ticks, CLB infections were found in 2 Haemaphysalis wellingtoni individuals. In a
phylogenetic analysis, the Coxiella 16S rRNA gene detected in this study formed a separate clade from
sequences found in ticks of the same genus. In contrast, the phylogenetic relationships based on groEL
and rpoB revealed that these two genes from H. wellingtoni ticks grouped with CLB from the same
tick genus (Haemaphysalis). This study is the first to report the presence of CLB in H. wellingtoni ticks
associated with the Great Hornbill, Buceros bicornis in Thailand. Three genes of CLB studied herein
were grouped separately with Coxiella burnetii (pathogenic strain). The effects of CLB in the ticks and
Buceros bicornis require further investigation.