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.

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.

Cytotaxonomy, morphology and ecology of the Simulium nobile species group (Diptera: Simuliidae) in Thailand.

The polytene chromosomes of 512 larvae of the Simulium nobile species group collected from 16 stream sites in northern, central and southern Thailand were examined. Band-by- band comparisons relative to the established standard chromosome map for the subgenus Simulium distinguished the 2 species of this group, S. nobile and S. nodosum. The differences are mainly due to the position of the nucleolar organizer, pseudochromocenter, and fixed and polymorphic inversions. S. nobile is a monomorphic species, while S. nodosum is a polymorphic species. The morphology of these taxa is described based on the gill filaments and the color of the antennae and female genitalia. S. nobile is distributed in southern Thailand at low altitudes, whereas the distribution of S. nodosum is in the north at higher altitudes.

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.

Metaphase karyotypes of fruit flies of Thailand. I. Five sibling species of the Bactrocera dorsalis complex.

Natural populations of fruit flies of the Bactrocera dorsalis complex exhibit chromosomal variation based on differences in the amount and distribution of constitutive heterochromatin in the centromeric regions of the autosomes and the sex chromosomes. The chromosomal variation, coupled with differences in external morphology and host plant specific preferences, strongly suggest the existence of 5 closely related species within the B. dorsalis complex that have provisionally been designated B. dorsalis species B, C, D, and E in contrast with B. dorsalis s.s. (species A). Analysis of heterochromatin in autosomes and sex chromosomes has revealed 4 distinct groups of mitotic karyotypes. Bactrocera dorsalis is the only representative of Group I, which is characterized by the typical metacentric X chromosome and major blocks of centromeric heterochromatin in autosomes 5 and 6. Group 2 consists of species B and C, which show prominent landmarks of pericentric heterochromatin in all autosomes and in the X chromosome. Group 3 comprises species D, which is characterized by conspicuous blocks of pericentric heterochromatin in all autosomes but the long arm of the subtelocentric X chromosome is euchromatic and lacks a major portion of centromeric heterochromatin. Species E belongs to Group 4, which differs from Group 3 in having major blocks of heterochromatin at the distal portion of the X chromosome in addition to the prominent landmarks of pericentric heterochromatin in all autosomes. Chromosomal evolution among closely related species within the B. dorsalis complex clearly involves the presence or absence of constitutive heterochromatin in the centromeric regions of autosomes as well as in the X chromosome.