Special Issue "Advances in the Biology of Leptospira, Borrelia and Other Spirochetes"

A special issue of Biology (ISSN 2079-7737). This special issue belongs to the section "Microbiology".

Deadline for manuscript submissions: closed (30 September 2021).

Special Issue Editors

Prof. Dr. Filippo Fratini
E-Mail Website
Guest Editor
Dipartimento di Scienze Veterinarie, Viale delle Piagge 2, Università di Pisa, Pisa, Italy
Interests: bacterial infectious disease; zoonosis; antimicrobial resistance; wildlife
Special Issues, Collections and Topics in MDPI journals
Dr. Giovanni Cilia
E-Mail Website
Guest Editor

Special Issue Information

Spirochetes are a Gram-negative bacteria group characterized by spiral-shaped cells, some of which are serious pathogens for humans and animals, which cause diseases and are responsible for zoonosis. Among them, the most known are Leptospira species, which cause leptospirosis; Borrelia burgdorferi, Borrelia afzelii, and Borrelia gariniii, which are responsible for Lyme disease; Borrelia recurrentis, which causes relapsing fever; Treponema pallidum, which is the causative agent in syphilis and yaws; and Brachyspira pilosicoli and Brachyspira aalborgi, which cause intestinal spirochetosis.

Spirochete infections are re-emerging and widespread infectious diseases and zoonosis, globally distributed due to a large variety of wild and domestic animal species that can play a role as natural or accidental hosts. Moreover, specific animal species play an important role as reservoirs for particular spirochete species, such as members of the genera Leptospira and Treponema, while other are transmitted by ticks (e.g., Borrelia species).

The constant modification of ecosystems and habitats, especially for wildlife, the constant expansion of wild animals into urban areas which increases the possibility of direct or indirect contact with humans and domestic animals, and the emerging antibiotic-resistance phenomena highlight a new host–pathogen interaction as a consequence of the biological modification of these bacterial strains. Additionally, all of these features have important roles in human health and the epidemiology of these diseases.

The topic of this Special Issue is to investigate the biology of spirochetes, highlighting their biological modifications concerning new antibiotic resistance; new host–pathogen interactions; new genetic and genomic modifications; new signs, symptoms, and epidemiological features; new diagnoses; and other new aspects concerning the evolution of spirochetal diseases. You are invited to submit either an original article, a communication, or a review summarizing the different aspects discussed above. Manuscripts highlighting and documenting any aspect of the investigation of spirochetal diseases in humans, environment, wildlife, and domestic animals are welcome, and will be considered for publication.

Prof. Dr. Filippo Fratini
Dr. Giovanni Cilia
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Biology is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Leptospira
  • leptospirosis
  • pathology
  • zoonosis
  • wildlife
  • human health
  • infectious disease
  • domestic animal
  • Borrelia
  • Lyme disease
  • Treponema
  • syphilis
  • yaws
  • releasing fever
  • antibiotic resistance
  • host–pathogen interactions
  • Brachyspira
  • One Health

Published Papers (7 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

Article
Influence of Season, Population and Individual Characteristics on the Prevalence of Leptospira spp. in Bank Voles in North-West Germany
Biology 2021, 10(9), 933; https://doi.org/10.3390/biology10090933 - 18 Sep 2021
Viewed by 614
Abstract
Leptospirosis is a worldwide zoonotic disease with more than 1 million human cases annually. Infections are associated with direct contact to infected animals or indirect contact to contaminated water or soil. As not much is known about the prevalence and host specificity of [...] Read more.
Leptospirosis is a worldwide zoonotic disease with more than 1 million human cases annually. Infections are associated with direct contact to infected animals or indirect contact to contaminated water or soil. As not much is known about the prevalence and host specificity of Leptospira spp. in bank voles (Clethrionomys glareolus), our study aimed to evaluate Leptospira spp. prevalence and genomospecies distribution as well as the influence of season, host abundance and individual characteristics on the Leptospira prevalence. Bank voles, which are abundant and widely distributed in forest habitats, were collected in the years 2018 to 2020 in North-West Germany, covering parts of North Rhine-Westphalia and Lower Saxony. The DNA of 1817 kidney samples was analyzed by real-time PCR targeting the lipl32 gene. Positive samples were further analyzed by targeting the secY gene to determine Leptospira genomospecies and multilocus sequence typing (MLST) to determine the sequence type (ST). The overall prevalence was 7.5% (95% confidence interval: 6.4–8.9). Leptospira interrogans (83.3%), L. kirschneri (11.5%) and L. borgpetersenii (5.2%) were detected in bank voles. Increasing body weight as a proxy for age increased the individual infection probability. Only in years with high bank vole abundance was this probability significantly higher in males than in females. Even if case numbers of human leptospirosis in Germany are low, our study shows that pathogenic Leptospira spp. are present and thus a persisting potential source for human infection. Full article
(This article belongs to the Special Issue Advances in the Biology of Leptospira, Borrelia and Other Spirochetes)
Show Figures

Figure 1

Article
New Insights on Leptospira Infections in a Canine Population from North Sardinia, Italy: A Sero-Epidemiological Study
Biology 2021, 10(6), 507; https://doi.org/10.3390/biology10060507 - 07 Jun 2021
Cited by 1 | Viewed by 806
Abstract
Leptospirosis is a widespread zoonosis recognized as a re-emerging infectious disease in a wide variety of animal species, including humans and dogs. No data exist regarding the presence of Leptospira species in the canine population of Sardinia Island. This study reports the first [...] Read more.
Leptospirosis is a widespread zoonosis recognized as a re-emerging infectious disease in a wide variety of animal species, including humans and dogs. No data exist regarding the presence of Leptospira species in the canine population of Sardinia Island. This study reports the first sero-survey for leptospirosis in kennel and owned dogs from six areas of the north of Sardinia. Sera from 1296 dogs were tested by microscopic agglutination test (MAT) specific for nine different serovars that are known to be well widespread in the Mediterranean environment. Moreover, kidney homogenates from rodents collected from the study area were also analyzed by LipL32 real-time PCR and multi-locus sequence type (MLST) on the basis of the analysis of seven concatenated loci. A total of 13% of the examined sera (95%CI: 11–15) tested positive for one or more serovars of Leptospira MAT detected; antibodies for serogroup Icterohaemorrhagiae (57%; 95%CI: 49–65) were the most common, followed by serovars Bratislava (22%; 95%CI: 16–28), Canicola (14%; 95%CI: 9–19), and Grippotyphosa (7%; 95%CI: 3–11). MLST analyses on isolates from rodents identified L. interrogans and L. borgpetersenii genomospecies. Different serovars belonging to pathogenic Leptospira serogroups are circulating in dogs from the island. Moreover, data obtained from rodents, indicated that rodents likely act as reservoir of spirochetes. Further sero-epidemiological studies are needed in order to obtain data from other collection sites in Sardinia and to increase the information on Leptospira species circulating in this area. Full article
(This article belongs to the Special Issue Advances in the Biology of Leptospira, Borrelia and Other Spirochetes)
Show Figures

Figure 1

Communication
Leptospira fainei Detected in Testicles and Epididymis of Wild Boar (Sus scrofa)
Biology 2021, 10(3), 193; https://doi.org/10.3390/biology10030193 - 04 Mar 2021
Viewed by 707
Abstract
Leptospirosis is a re-emerging and worldwide diffused zoonosis. Recently, the high importance of their epidemiology was explained by the intermediate Leptospira strains. Among these strains, Leptospira fainei was the first intermediate strain detected in domestic and wild swine. Wild boars (Sus scrofa [...] Read more.
Leptospirosis is a re-emerging and worldwide diffused zoonosis. Recently, the high importance of their epidemiology was explained by the intermediate Leptospira strains. Among these strains, Leptospira fainei was the first intermediate strain detected in domestic and wild swine. Wild boars (Sus scrofa) are well known as a reservoir, as well as all swine, for pathogenic Leptospira, but very little information is available concerning intermediate Leptospira infection. The investigation aim was to evaluate if intermediate Leptospira can infect the reproductive systems of wild boars hunted in the Tuscany region (Italy), as previously demonstrated for pathogenic ones. The reproductive system tissue (testicles, epididymides, uteri), and placentas and fetuses, were collected from 200 regularly hunted animals. Bacteriological examination and real-time PCR were performed to detect intermediate Leptospira DNA. Unfortunately, no isolates were obtained. Using real-time PCR, in six (3%) male organs (both testicles and epididymis), intermediate Leptospira DNA was found. The amplification of the 16S rRNA gene identified that all DNA obtained belong to Leptospira fainei. The results of this investigation highlighted for the first time the localization of Leptospira fainei in the male wild boar reproductive system, opening up a new avenue to further investigate. Full article
(This article belongs to the Special Issue Advances in the Biology of Leptospira, Borrelia and Other Spirochetes)
Show Figures

Figure 1

Article
The Platelet Fraction Is a Novel Reservoir to Detect Lyme Borrelia in Blood
Biology 2020, 9(11), 366; https://doi.org/10.3390/biology9110366 - 29 Oct 2020
Viewed by 2134
Abstract
Serological diagnosis of Lyme disease suffers from considerable limitations. Yet, the technique cannot currently be replaced by direct detection methods, such as bacterial culture or molecular analysis, due to their inadequate sensitivity. The low bacterial burden in vasculature and lack of consensus around [...] Read more.
Serological diagnosis of Lyme disease suffers from considerable limitations. Yet, the technique cannot currently be replaced by direct detection methods, such as bacterial culture or molecular analysis, due to their inadequate sensitivity. The low bacterial burden in vasculature and lack of consensus around blood-based isolation of the causative pathogen, Borrelia burgdorferi, are central to this challenge. We therefore addressed methodological optimization of Borrelia recovery from blood, first by analyzing existing protocols, and then by using experimentally infected human blood to identify the processing conditions and fractions that increase Borrelia yield. In this proof-of-concept study, we now report two opportunities to improve recovery and detection of Borrelia from clinical samples. To enhance pathogen viability and cultivability during whole blood collection, citrate anticoagulant is superior to more commonly used EDTA. Despite the widespread reliance on serum and plasma as analytes, we found that the platelet fraction of blood concentrates Borrelia, providing an enriched resource for direct pathogen detection by microscopy, laboratory culture, Western blot, and PCR. The potential for platelets to serve as a reservoir for Borrelia and its diagnostic targets may transform direct clinical detection of this pathogen. Full article
(This article belongs to the Special Issue Advances in the Biology of Leptospira, Borrelia and Other Spirochetes)
Show Figures

Graphical abstract

Review

Jump to: Research

Review
Borreliae Part 2: Borrelia Relapsing Fever Group and Unclassified Borrelia
Biology 2021, 10(11), 1117; https://doi.org/10.3390/biology10111117 - 29 Oct 2021
Cited by 1 | Viewed by 576
Abstract
Borreliae of the relapsing fever group (RFG) are heterogenous and can be divided mainly into three groups according to vectors, namely the soft-tick-borne relapsing fever (STBRF) Borreliae, the hard-tick-borne relapsing fever (HTBRF) Borreliae, the louse-borne relapsing fever (LBRF) Borreliae, and [...] Read more.
Borreliae of the relapsing fever group (RFG) are heterogenous and can be divided mainly into three groups according to vectors, namely the soft-tick-borne relapsing fever (STBRF) Borreliae, the hard-tick-borne relapsing fever (HTBRF) Borreliae, the louse-borne relapsing fever (LBRF) Borreliae, and the avian relapsing fever ones. With respect to the geographical distribution, the STBRF Borreliae are further subdivided into Old World and New World strains. Except for the Avian relapsing fever group Borreliae, which cause avian spirochetosis, all the others share infectivity in humans. They are indeed the etiological agent of both endemic and epidemic forms of relapsing fever, causing high spirochaetemia and fever. Vectors are primarily soft ticks of Ornithodoros spp. in the STBRF group; hard ticks, notably Ixodes sp., Amblyomma sp., Dermacentor sp., and Rhipicephalus sp., in the HTBRF group; and the louse pediculus humanus humanus in the TBRF one. A recent hypothesis was supported for a common ancestor of RFG Borreliae, transmitted at the beginning by hard-body ticks. Accordingly, STBRF Borreliae switched to use soft-bodied ticks as a vector, which was followed by the use of lice by Borrelia recurrentis. There are also new candidate species of Borreliae, at present unclassified, which are also described in this review. Full article
(This article belongs to the Special Issue Advances in the Biology of Leptospira, Borrelia and Other Spirochetes)
Show Figures

Figure 1

Review
Borreliae Part 1: Borrelia Lyme Group and Echidna-Reptile Group
Biology 2021, 10(10), 1036; https://doi.org/10.3390/biology10101036 - 12 Oct 2021
Cited by 1 | Viewed by 869
Abstract
Borreliae are divided into three groups, namely the Lyme group (LG), the Echidna-Reptile group (REPG) and the Relapsing Fever group (RFG). Currently, only Borrelia of the Lyme and RF groups (not all) cause infection in humans. Borreliae of the Echidna-Reptile group represent a [...] Read more.
Borreliae are divided into three groups, namely the Lyme group (LG), the Echidna-Reptile group (REPG) and the Relapsing Fever group (RFG). Currently, only Borrelia of the Lyme and RF groups (not all) cause infection in humans. Borreliae of the Echidna-Reptile group represent a new monophyletic group of spirochaetes, which infect amphibians and reptiles. In addition to a general description of the phylum Spirochaetales, including a brief historical digression on spirochaetosis, in the present review Borreliae of Lyme and Echidna-Reptile groups are described, discussing the ecology with vectors and hosts as well as microbiological features and molecular characterization. Furthermore, differences between LG and RFG are discussed with respect to the clinical manifestations. In humans, LG Borreliae are organotropic and cause erythema migrans in the early phase of the disease, while RFG Borreliae give high spirochaetemia with fever, without the development of erythema migrans. With respect of LG Borreliae, recently Borrelia mayonii, with intermediate characteristics between LG and RFG, has been identified. As part of the LG, it gives erythema migrans but also high spirochaetemia with fever. Hard ticks are vectors for both LG and REPG groups, but in LG they are mostly Ixodes sp. ticks, while in REPG vectors do not belong to that genus. Full article
(This article belongs to the Special Issue Advances in the Biology of Leptospira, Borrelia and Other Spirochetes)
Show Figures

Figure 1

Review
Molecular Mechanisms of Borrelia burgdorferi Phagocytosis and Intracellular Processing by Human Macrophages
Biology 2021, 10(7), 567; https://doi.org/10.3390/biology10070567 - 22 Jun 2021
Viewed by 1013
Abstract
Lyme disease is the most common vector-borne illness in North America and Europe. Its causative agents are spirochetes of the Borrelia burgdorferi sensu latu complex. Infection with borreliae can manifest in different tissues, most commonly in the skin and joints, [...] Read more.
Lyme disease is the most common vector-borne illness in North America and Europe. Its causative agents are spirochetes of the Borrelia burgdorferi sensu latu complex. Infection with borreliae can manifest in different tissues, most commonly in the skin and joints, but in severe cases also in the nervous systems and the heart. The immune response of the host is a crucial factor for preventing the development or progression of Lyme disease. Macrophages are part of the innate immune system and thus one of the first cells to encounter infecting borreliae. As professional phagocytes, they are capable of recognition, uptake, intracellular processing and final elimination of borreliae. This sequence of events involves the initial capture and internalization by actin-rich cellular protrusions, filopodia and coiling pseudopods. Uptake into phagosomes is followed by compaction of the elongated spirochetes and degradation in mature phagolysosomes. In this review, we discuss the current knowledge about the processes and molecular mechanisms involved in recognition, capturing, uptake and intracellular processing of Borrelia by human macrophages. Moreover, we highlight interactions between macrophages and other cells of the immune system during these processes and point out open questions in the intracellular processing of borreliae, which include potential escape strategies of Borrelia. Full article
(This article belongs to the Special Issue Advances in the Biology of Leptospira, Borrelia and Other Spirochetes)
Show Figures

Figure 1

Back to TopTop