Coxiella-like bacteria in Haemaphysalis wellingtoni ticks associated with Great Hornbill, Buceros bicornis.

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.

A new record of Rickettsia japonica in ticks infesting a Burmese ferret-badger in Thailand.

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.

A new record of Rickettsia japonica in ticks infesting a Burmese ferret-badger in Thailand

@#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.

Coxiella-like bacteria in Haemaphysalis wellingtoni ticks associated with Great Hornbill, Buceros bicornis

@#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.

Molecular characterization of Pegarn: a Drosophila homolog of UNC-51 kinase.

We have isolated and characterized the gene encoding a Drosophila melanogaster homolog of Caenorhabditis elegans UNC-51 (uncoordinated movement-51): Pegarn. Developmental Northern blot shows the Pegarn gene is expressed at all stages of development. The protein is detected throughout the Drosophila third instar larval central nervous system (CNS) in axons projecting out from the ventral ganglion and in the optic anlagen of the optic lobe. Heterozygous Pegarn mutant embryos show defects in larval axonal neuronal patterning, but survive to adulthood. Homozygous mutants have an even more deformed pattern of neuronal development and do not survive through the larval stages. The data from this research suggest the critical roles of Pegarn in CNS and PNS axonal formation in Drosophila melanogaster and indicates its similar role in other multicellular species.

Tick-borne pathogens and diseases of animals and humans in Thailand.

Tick-borne pathogens in Thailand can cause diseases that result in productivity and economic losses in the livestock sector as well as cause debilitating illnesses in humans and their companion animals. With the advent of molecular techniques, accurate identification of tick-borne pathogens and precise diagnosis of disease is now available. This literature review summarizes the various tick-borne pathogens that have been isolated from ticks and their vertebrate hosts in Thailand, covering those protozoa, rickettsiae, bacteria and viruses most responsible for human and veterinary disease with particular emphasis on those that have been characterized molecularly.

Wolbachia and bacteriophage WO-B density of Wolbachia A-infected Aedes albopictus mosquito.

Wolbachia are maternally inherited symbiotic bacteria capable of inducing an extensive range of reproductive abnormalities in their hosts, including cytoplasmic incompatibility (CI). Its density (concentration) is likely to influence the penetrance of CI in incompatible crosses. The variations of Wolbachia density could also be linked with phage WO density. We determined the relative density (relative concentration) of prophage WO orf7 and Wolbachia (phage-to-bacteria ratio) during early developmental and adult stages of singly infected Aedes albopictus mosquito (Wolbachia A-infected) by using real-time quantitative PCR. Phage WO and Wolbachia did not develop at the same rate. Relative Wolbachia density (bacteria-to-host ratio) was high later in development (adult stages) whilst relative prophage WO density (phage-to-bacteria ratio) was low in the adult stages. Furthermore, 12-d-old adults of singly infected female mosquito had the highest Wolbachia density. In contrast, the larval stage 4 (L4) contained the highest prophage WO-B orf7 density. The association of hosts-Wolbachia-phage among diverse species is different. Thus, if phage and Wolbachia are involved in CI mechanism, the information of this association should be acquired for each specific type of organism for future use of population replacement or gene drive system.

Bacteriophage WO-B and Wolbachia in natural mosquito hosts: infection incidence, transmission mode and relative density.

Bacteriophages of Wolbachia bacteria have been proposed as a potential transformation tool for genetically modifying mosquito vectors. In this study, we report the presence of the WO-B class of Wolbachia-associated phages among natural populations of several mosquito hosts. Eighty-eight percent (22/25) of Wolbachia-infected mosquito species surveyed were found to contain WO-B phages. WO-B phage orf7 sequence analysis suggested that a single strain of WO-B phage was found in most singly (23/24) or doubly (1/1) Wolbachia-infected mosquitoes. However, the single Wolbachia strain infecting Aedes perplexus was found to harbour at least two different WO-B phages. Phylogenetic analysis suggested that horizontal transmission of WO-B phages has occurred on an evolutionary scale between the Wolbachia residing in mosquitoes. On an ecological scale, a low trend of co-transmission occurred among specific WO-B phages within Wolbachia of each mosquito species. Assessment of the density of WO-B phage by real-time quantitative polymerase chain reaction (RTQ-PCR) revealed an average relative density of 7.76 x 10(5)+/- 1.61 x 10(5) orf7 copies per individual mosquito for a single Wolbachia strain infecting mosquitoes, but a threefold higher density in the doubly Wolbachia-infected Aedes albopictus. However, the average combined density of WO-B phage(s) did not correlate with that of their Wolbachia hosts, which varied in different mosquito species. We also confirmed the presence of WO-B-like virus particles in the laboratory colony of Ae. albopictus (KLPP) morphologically, by transmission electron microscopy (TEM). The viral-like particles were detected after purification and filtration of Ae. albopictus ovary extract, suggesting that at least one WO-B-like phage is active (temperate) within the Wolbachia of this mosquito vector. Nevertheless, the idea of utilizing these bacteriophages as transformation vectors still needs more investigation and is likely to be unfeasible.