Phylogenetic analysis of the spirochete Borrelia microti, a potential agent of relapsing fever in Iran

Prevalence of Lyme Disease and Relapsing Fever Borrelia spp. in Vectors, Animals, and Humans within a One Health Approach in Mediterranean Countries

The genus Borrelia has been divided into Borreliella spp., which can cause Lyme Disease (LD), and Borrelia spp., which can cause Relapsing Fever (RF). The distribution of genus Borrelia has broadened due to factors such as climate change, alterations in land use, and enhanced human and animal mobility. Consequently, there is an increasing necessity for a One Health strategy to identify the key components in the Borrelia transmission cycle by monitoring the human-animal-environment interactions. The aim of this study is to summarize all accessible data to increase our understanding and provide a comprehensive overview of Borrelia distribution in the Mediterranean region. Databases including PubMed, Google Scholar, and Google were searched to determine the presence of Borreliella and Borrelia spp. in vectors, animals, and humans in countries around the Mediterranean Sea. A total of 3026 were identified and screened and after exclusion of papers that did not fulfill the including criteria, 429 were used. After examination of the available literature, it was revealed that various species associated with LD and RF are prevalent in vectors, animals, and humans in Mediterranean countries and should be monitored in order to effectively manage and prevent potential infections.

Borrelia theileri infections in Rhipicephalus annulatus ticks from the north of Iran

Ticks serve as vectors and reservoirs of various Borrelia species, potentially causing diseases in humans and animals. Mazandaran, a fertile green land in northern Iran, provides ample grazing grounds for livestock and harbors at least 26 hard tick species. This study investigated Borrelia infection in hard ticks from forest areas in this region and compared their genetic identity with the species data in the GenBank database. A total of 2,049 ticks were collected manually from mammalian hosts or using dragging and flagging methods. These ticks were then grouped into 190 pools and 41 individuals based on host, species, developmental stage, and gender. A real-time PCR (qPCR) detected Borrelia DNA in 26 pools from female, male, and nymph of Rhipicephalus annulatus (n = 17) and Ixodes ricinus (n = 9) ticks and one individual female Haemaphysalis punctata tick. The generated partial flaB and glpQ sequences from qPCR-positive Rh. annulatus ticks exhibited the highest identities of 98.1-100% and 98.2% with Borrelia theileri and closely related undefined isolates. Additionally, in phylogenetic analysis, these sequences clustered within well-supported clades with B. theileri and the closely related undefined isolates from various geographic regions, confirming the presence of B. theileri in the north of Iran. Divergence in B. theileri flaB and glpQ sequences across various geographical areas suggests potential subspeciation driven by adaptations to different tick species. This divergence in our flaB sequences implies the possible introduction of B. theileri-infected ticks from different geographical origins into Iran.

Borrelia duttonii-like spirochetes parasitize Meriones persicus in East Azerbaijan Province of Iran

In Iran, Borrelia persica and Borrelia microti/microti-like borreliae have been established as causative agents of tickborne relapsing fever (TBRF). However, the epidemiology of two previously described species, Borrelia balthazardi and Borrelia latyschewii (latychevi), has remained elusive for many years. We investigated Borrelia infection in various rodents and small mammals in the TBRF endemic East Azerbaijan Province, northwestern Iran, where B. perisca and B. balthazardi might coexist. Among trapped animals (n=210), a 16S real-time PCR detected Borrelia DNA in 11 Meriones persicus. Multilocus sequence analysis (MLSA) using six different loci, including four coding regions (flaB, glpQ, groEL, p66) and two non-coding (rrs, IGS) followed by phylogeny revealed considerable sequence identity between the borreliae detected, B. microti, and East African Borrelia duttonii, and Borrelia recurrentis. Our results indicate that B. microti and microti-like borreliae, including the specimens previously characterized in the south of Iran and the present study, are different ecotypes of B. duttonii, i.e., exhibiting a single species/entity or descendants of a recent common ancestor. Our findings also suggest that the species we had long coined as B. balthazardi and the microti-like borreliae detected herein might be the same.

The Family Borreliaceae (Spirochaetales), a Diverse Group in Two Genera of Tick-Borne Spirochetes of Mammals, Birds, and Reptiles

Spirochetes of the family Borreliaceae are, with one exception, tick-borne pathogens of a variety of vertebrates. The family at present comprises two genera: Borrelia (Swellengrebel), which includes the agents of relapsing fever, avian spirochetosis, and bovine borreliosis, and Borreliella (Gupta et al.), which includes the agents of Lyme disease and was formerly known as 'Borrelia burgdorferi sensulato complex'. The two genera are distinguished not only by their disease associations but also biological features in the tick vector, including tissue location in unfed ticks and transovarial transmission. Borrelia species transmitted by argasid (soft) ticks tend to have more exclusive relationships with their tick vectors than do other Borrelia species and all Borreliella species that have ixodid (hard) ticks as vectors. The division of genera is supported by phylogenomic evidence from whole genomes and by several specific molecular markers. These distinguishing phylogenetic criteria also applied to three new species or isolates of Borrelia that were discovered in ixodid ticks of reptiles, a monotreme, and birds. Although the deep branching of the family from other spirochetes has been a challenge for inferences about evolution of the family, the discovery of related microorganisms in the gut microbiota of other arachnids suggests an ancestral origin for the family as symbionts of ticks and other arachnids.

Development of A Loop-Mediated Isothermal Amplification (LAMP) Assay for Detection of Relapsing Fever Borreliae

Background

This study aimed to develop a loop-mediated isothermal amplification (LAMP) assay for the rapid detection of tick-borne relapsing fever in resource-limited areas.

Methods

A set of six primers were designed based on the conserved regions of the Glycerophosphodiester phosphodiesterase (glpQ) gene of Borrelia species. For sensitivity assay, serial dilutions of a recombinant plasmid containing a 219bp sequence of the glpQ were prepared and used as the template DNA. The LAMP reactions containing the six primers and the reagents required for amplification were incubated at 60-65 °C for 60min in a Loopamp real-time turbidimeter. For the specificity test, DNA from 14 other bacteria were included in the assays, and double-distilled water was used as the negative control. Also, DNA from dried blood spots (DBSs) of spirochetemic mice, and blood samples from relapsing fever-suspected patients were examined by the LAMP along a Borrelia-specific nested PCR that targets the rrs-rrl-IGS region.

Results

The LAMP detected as low as 90glpQ copies in reactions. The primers reacted with DNA from DBS of spirochetemic mice showing spirochete concentrations of ≤ one per a 1000X microscopic field. In clinical samples, the LAMP assay showed a higher sensitivity compared to nested-PCR. The LAMP specificity was 100%, as the primers did not react with other bacteria DNA.

Conclusion

The high sensitivity and specificity of the test, along with the simplicity of the DNA extraction procedure, make the LAMP a reliable and adaptable tool for the diagnosis of tick-borne relapsing fever in rural endemic areas.

Infection of hard ticks in the Caspian Sea littoral of Iran with Lyme borreliosis and relapsing fever borreliae

The Caspian Sea littoral of Iran is home to various hard tick species, including Ixodes ricinus, the notorious vector of Lyme borreliosis (LB) in Eurasia. Here, in this area, we examined I. ricinus and other hard ticks, along with common rodents and small mammals for LB and relapsing fever (RF) borreliae infection. Ticks were collected from various mammalian hosts, including sheep, goats, cattle, camels, horses, dogs, donkeys, rodents, and hedgehogs. Rodents and small mammals were live-captured from different habitats. A real-time PCR for 16S rRNA sequence revealed borrelial DNA in 71 out of 501 (≈14 %) specimens belonging to I. ricinus and Rhipicephalus ticks. None of the rodents and small mammals showed borrelial infection in the viscera. PCR amplification and sequencing of a 600-bp sequence of the flaB identified Borrelia bavariensis, Borrelia garinii, Borrelia afzelii, and Borrelia valaisiana, and the RF Borrelia, B. miyamotoi in I. ricinus ticks. The RF-like Borrelia in Rhipicephalus ticks shared the highest identity (98.97 %) with an isolate infecting Haemaphysalis megaspinosa ticks in Japan. Our phylogeny and BLAST analysis suggest the range extension of the European I. ricinus-associated borreliae into the north of Iran.

Ornithodoros savignyi, the Tick Vector of "Candidatus Borrelia kalaharica" in Nigeria

Endemic tick-borne relapsing fever (TBRF) has not been documented in Nigeria, yet clinically compatible cases have been described, and soft tick species are endemic in surrounding countries. Consequently, our aim was to investigate if TBRF-associated Borrelia is present in Nigeria. To address this, we examined 49 soft tick pools to identify the tick species and to screen for Borrelia The tick species was revealed by 16S rRNA gene amplification and Sanger sequencing to be Ornithodoros savignyi, an aggressive, multihost, rapidly feeding species with significant veterinary impact. We detected a Borrelia organism in 3 of 49 pooled samples (6%). Molecular analysis of amplified 16S rRNA and flagellin genes and intragenic spacer fragments disclosed that this Borrelia organism was synonymous with the recently described organism "Candidatus Borrelia kalaharica," identified in a tourist returning to Germany from South Africa. Given the widespread endemic range of this tick vector, TBRF should be considered part of the differential diagnosis for patients with fever returning from arid areas of Africa and further afield.

Relapsing Fevers: Neglected Tick-Borne Diseases

Relapsing fever still remains a neglected disease and little is known on its reservoir, tick vector and physiopathology in the vertebrate host. The disease occurs in temperate as well as tropical countries. Relapsing fever borreliae are spirochaetes, members of the Borreliaceae family which also contain Lyme disease spirochaetes. They are mainly transmitted by Ornithodoros soft ticks, but some species are vectored by ixodid ticks. Traditionally a Borrelia species is associated with a specific vector in a particular geographical area. However, new species are regularly described, and taxonomical uncertainties deserve further investigations to better understand Borrelia vector/host adaptation. The medical importance of Borrelia miyamotoi, transmitted by Ixodes spp., has recently spawned new interest in this bacterial group. In this review, recent data on tick-host-pathogen interactions for tick-borne relapsing fevers is presented, with special focus on B. miyamotoi.

The fauna and perspective of rodentia ectoparasites in Iran relying on their roles within public health and veterinary characteristics

Historically, rodents-ectoparasites are responsible for many diseases in human and domestic animal communities because they are well-adapted to the environment and nutritional resources. In addition, ectoparasites can affect the reproductive rates, ecological fitness and the dispersal pattern of their hosts. Data was compiled through all publications relating to ectoparasites fauna from Iranian rodents. Host specificity, rodent-parasites interaction, geographical distribution, ecological trends as well as the medical or veterinary importance of ectoparasites are considered in this review. Also, results compared with other equal global findings. According to the obtained information, the genus Hyalomma considered being the major vector of Crimean-Congo hemorrhagic fever. Sistan-Balouchistan, Isfahan, Fars and Khuzestan are endemic provinces of this disease in Iran. Ixodes ticks (especially Hyalomma spp.) commonly existed throughout the months but had high activity in spring and late autumn seasons. Muridae as the most diversified rodent family was more reiterated exploited host by all parasites in this knowledge. Tatera indica confirmed as a positive host for Francisella tularensis by serological test but the definitive reservoir is still unclear in Iran. Meriones persicus as a nocturnal jird has been permanently presented in semi-desert areas except Dasht-e Kavir desert. This rodent was the frequent host for Pulicid fleas followed by Mus musculus and Cricetulus migratorius (Cricetidae). Rattus norvegicus was specialized host for Polyplax spinulosa (spiny rat louse). Pulex irritans from Pulicidae was spread in particularly west of Iran which known as an endemic focus of plague. Mites were high diversity than other taxa. The domestic vertebrates (sheep, goat and cattle) were primitive hosts and rodents were discovered as auxiliary hosts for ticks in Iran apparently. The available data suggested that lice had a type of model of host specificity due to their morphological traits. Meanwhile, Alborz and Zagros mountains ranges provided the specialized habitats for animals which have been surrounded by northern and western regions. Perhaps these mountainous areas can prevent gene flow between local mammalian populations. Notably, the genealogy of parasite genome can orient toward the evolutionary process into speciation point. In general, more researches are needed to decipher the whole sights of host-parasite association and the role of ectoparasites within zoonosis diseases.

Relapsing fever causative agent in Southern Iran is a closely related species to East African borreliae

We obtained two blood samples from relapsing fever patients residing in Jask County, Hormozgan Province, southern Iran in 2013. Sequencing of a partial fragment of glpQ from two samples, and further characterization of one of them by analyzing flaB gene, and 16S-23S spacer (IGS) revealed the greatest sequence identity with East African borreliae, Borrelia recurrentis, and Borrelia duttonii, and Borrelia microti from Iran. Phylogenetic analyses of glpQ, flaB, and concatenated sequences (glpQ, flab, and IGS) clustered these sequences amongst East African Relapsing fever borreliae and B. microti from Iran. However, the more discriminatory IGS disclosed a unique 8-bp signature (CAGCCTAA) separating these from B. microti and indeed other relapsing fever borreliae. In southern Iran, relapsing fever cases are mostly from localities in which O. erraticus ticks, the notorious vector of B. microti, prevail. There are chances that this argasid tick serves as a host and vector of several closely related species or ecotypes including the one we identified in the present study. The distribution of this Borrelia species remains to be elucidated, but it is assumed to be endemic to lowland areas of the Hormozgan Province, as well as Sistan va Baluchistan in the southeast and South Khorasan (in Persian: Khorasan-e Jonobi) in the east of Iran.

A case of canine borreliosis in Iran caused by Borrelia persica

Tick-borne relapsing fever is an endemic disease in Iran, with most cases attributed to infection by Borrelia persica, which is transmitted by Ornithodoros tholozani soft ticks. Here, we report spirochetemia in blood of a puppy residing in Tehran, Iran. The causative species was identified by use of highly discriminative IGS sequencing; the 489 bp IGS sequence obtained in our study showed 99% identity (100% coverage) when compared with B. persica sequences derived from clinical cases or from O. tholozani ticks. Our IGS sequence also showed 99% similarity over 414 bp (85% coverage) with a strain from a domestic dog, and 96% over 328 bp (69% coverage) with a strain from a domestic cat. Pet-keeping in cosmopolitan cities like Tehran has become increasingly popular in recent years. Animals are often transported into the city in cages or cardboard boxes that might also harbor minute tick larvae and/or early stages of the nymphs bringing them into the urban environment. This may pose a threat to household members who buy and keep these puppies and as a result may come into close contact with infected ticks.

Relapsing Fever Borreliae: A Global Review

Relapsing fever borreliae were notorious and feared infectious agents that earned their place in history through their devastating impact as causes of both epidemic and endemic infection. They are now considered more as an oddity, and their burden of infection is largely overshadowed by other infections such as malaria, which presents in a similar clinical way. Despite this, they remain the most common bacterial infection in some developing countries. Transmitted by soft ticks or lice, these fascinating spirochetes have evolved a myriad of mechanisms to survive within their diverse environments.

Relapsing fever borreliae in Africa

The study of relapsing fever borreliae in Africa has long suffered from the use of non-specific laboratory tools for the direct detection of these spirochetes in clinical and vector specimens. Accordingly, Borrelia hispanica, Borrelia crocidurae, Borrelia duttonii, and Borrelia recurrentis have traditionally been distinguished on the basis of geography and vector and the unproven hypothesis that each species was exclusive to one vector. The recent sequencing of three relapsing fever Borrelia genomes in our laboratory prompted the development of more specific tools and a reappraisal of the epidemiology in Africa. Five additional potential species still need to be cultured from clinical and vector sources in East Africa to further assess their uniqueness. Here, we review the molecular evidence of relapsing fever borreliae in hosts and ectoparasites in Africa and explore the diversity, geographical distribution, and vector association of these pathogens for Africans and travelers to Africa.