Soft tick relapsing fever (RF) infections cause adverse pregnancy outcomes, but the impact of hard tick RF on pregnancy is unknown. We assessed pregnancy outcomes in a mouse model of hard tick RF using the Borrelia miyamotoi clinical isolate CT14D4.

The Government of Japan has conducted weekly national surveillance of notifiable infectious diseases for over 25 years. As of December 2025, 87 notifiable diseases are under surveillance, although the list has changed over time as new infections have emerged and others have been reclassified. Although weekly data are openly available, their formatting and preparation have been labour-intensive. An open-source R package, jpinfect, has the potential to improve data accessibility and analytical workflows for these data sets. In this study, we used the jpinfect package to summarize national surveillance data for 12 acari-borne diseases in Japan from week 14 of 1999 to week 52 of 2025, by prefecture and sex. In total, 18 295 acari-borne disease cases were reported nationwide. Eight diseases reported at least one case. Of these, scrub typhus (56.6%), Japanese spotted fever (32.9%) and severe fever with thrombocytopenia syndrome (6.7%) together accounted for more than 95% of all cases. Scrub typhus case numbers remained stable and widely distributed across the country, except for in the northern island of Hokkaido. Confirmed cases of the other two tick-born diseases increased, notably in western Japan, but with new cases also reported in northern Japan. Lyme disease, relapsing fever and Q fever were sporadically reported at very low incidence levels (< 0.2 per 100 000 population). In addition to providing an updated epidemiological overview of acari-borne diseases in Japan, this report highlights the potential of jpinfect to streamline the generation of national situation reports. The surveillance and analytical framework described here could serve as a model for other countries in the Western Pacific Region.

A central Texas resident found an engorged Ornithodoros turicata tick attached to their ankle while at home. The tick tested positive for Borrelia turicatae, an agent for soft tick-borne relapsing fever. Three weeks earlier, the patient started experiencing febrile episodes, rash, and nausea, yet the etiological agent went undiagnosed.

Ixodidae ticks are vectors of pathogenic spirochetes from the Borrelia burgdorferi sensu lato (s.l.) complex and the relapsing fever (RF) group. The Russian Far East is endemic for borrelioses, yet data on the distribution and genetic diversity of Borrelia spp. in this region remain scarce. We examined 3107 Ixodidae ticks (Ixodes spp., Haemaphysalis spp., and Dermacentor silvarum), collected from two mainland provinces and five islands of the Russian Far East in 2005-2023. A total of 86 Borrelia afzelii, 297 Borrelia bavariensis, 81 Borrelia garinii, 44 Borrelia miyamotoi, and 33 unclassified RF borreliae were identified. Borrelia burgdorferi s.l. and B. miyamotoi were strongly associated with Ixodes spp., whereas unclassified RF borreliae were associated with Haemaphysalis spp. Among B. burgdorferi s.l. isolates, B. afzelii and B. bavariensis were found significantly more frequently in I. persulcatus compared to I. pavlovskyi, whereas B. garinii was significantly more common in I. pavlovskyi. Genetic characterization of B. burgdorferi s.l. revealed high haplotypic diversity, particularly within B. bavariensis and B. garinii. Among RF borreliae, all B. miyamotoi isolates were highly conserved and belonged to the Asian type. In contrast, unclassified RF borreliae were genetically variable and clustered with RF borreliae previously found in Haemaphysalis and Rhipicephalus ticks. The obtained results expand the understanding of the distribution and genetic diversity of Borrelia spp. in the Russian Far East.

Plasmodium vivax is one of the most common forms of malaria worldwide, notable for its ability to relapse from a dormant liver stage. Radical cure of Plasmodium as well as with P. ovale requires the use of 8-aminoquinolines to clear both blood and liver parasites; however, they are contraindicated in glucose-6-phosphate dehydrogenase (G6PD) deficiency due to the risk of causing hemolysis and in pregnant individuals due to the unknown G6PD status of the fetus. We present a case of a young pregnant woman with fever, nausea, and vomiting, who, upon blood peripheral smear and polymerase chain reaction (PCR) confirmation, was diagnosed with Plasmodium vivax. In this case, standard radical cure was not feasible during pregnancy, and a seven-day course of quinine and clindamycin was initiated for treatment of the acute blood-stage infection while G6PD results were awaited. Upon discharge, the patient was unable to obtain the medication and returned two months later with relapsing fevers, abdominal pain, and chills. Given presumed chloroquine-sensitive Plasmodium vivax, chloroquine remains the preferred agent for suppressive therapy during pregnancy. However, hydroxychloroquine was subsequently selected due to its more favorable side effect profile and improved tolerability for prolonged use. Both agents are considered safe in pregnancy. Before initiating treatment, G6PD screening is essential, as many antimalarial agents can precipitate hemolysis; quantitative testing is particularly important to distinguish deficiency from intermediate activity in heterozygous females. This case underscores the complexities of managing P. vivax infection in overlapping contraindications. It highlights the critical role of early and precise G6PD assessment, with quantitative assays in females being particularly essential, to inform safe administration of antimalarial therapy. These findings emphasize the necessity of individualized management strategies, especially for vulnerable migrant populations, and the importance of a structured follow-up plan to prevent relapse and ensure the delivery of definitive treatment.

Laryngopharyngeal involvement in Behçet's syndrome is rare but clinically significant because it may cause severe odynophagia, dysphagia, and airway compromise. Optimal treatment has not been established, and irreversible structural sequelae, including laryngopharyngeal stenosis and ulcer scarring, may occur. We describe two men with Behçet's syndrome and symptomatic laryngopharyngeal involvement who showed rapid improvement after infliximab administration following an insufficient response to corticosteroids. In case 1, a 25-year-old man was classified as having suspected Behçet's syndrome based on recurrent oral ulcers, pharyngeal ulceration, arthritis, folliculitis-like skin lesions, and previous episodes of abdominal pain. He developed severe pharyngeal pain and dysphagia due to ulcerative lesions extending from the posterior pharyngeal wall to the esophageal inlet. Intravenous prednisolone resulted in limited endoscopic and symptomatic improvement, whereas infliximab promptly relieved pain and restored oral intake, with no recurrence over 14 years of follow-up. In case 2, a 29-year-old man presented with recurrent fever, oral aphthae, genital ulcers, arthritis, erythema nodosum-like lesions, and pharyngeal and laryngeal mucosal lesions associated with dysphagia. His symptoms and laryngoscopic abnormalities improved promptly after infliximab administration following an inadequate response to prednisolone. These cases underscore the importance of considering early anti-tumor necrosis factor-α therapy in steroid-refractory or relapsing laryngopharyngeal Behçet's syndrome, because progression to irreversible structural complications, including stenosis and adhesion, may necessitate surgical intervention if inflammation is not controlled before permanent damage occurs.

Ornithodoros (Alectorobius) puertoricensis, a soft tick previously known to inhabit the Neotropical region, is reported for the first time in Sabinas, Coahuila, Mexico, representing its northernmost record and extending its range into the Nearctic region. Specimens were collected from rock squirrel (Otospermophilus variegatus) burrows and identified using morphological and molecular analyses, including mitochondrial 16S rDNA sequencing. Phylogenetic analysis supported the species identity. This record expands the known distribution of O. (A.) puertoricensis and highlights its potential role in pathogen transmission, highlighting its ecological and public health significance.

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a UBA1-driven hemato-inflammatory disorder that mimics relapsing polychondritis, vasculitis, and myelodysplastic syndromes, often causing diagnostic delay. We describe a case presenting with relapsing polychondritis-like features and summarize, through a focused literature review, its diagnostic pathway and therapeutic implications. A 74-year-old man presented with three weeks of fever, auricular and nasal chondritis, iritis, and pulmonary infiltrates. Inflammatory markers were elevated with macrocytic anaemia. Antimicrobial therapy failed, whereas glucocorticoids produced rapid defervescence and clinical improvement. Bone-marrow examination revealed cytoplasmic vacuoles in myeloid precursors with dysplastic features. Sanger sequencing of UBA1 exon 3 on peripheral-blood DNA identified the canonical variant c.122T > C, p.(Met41Thr) as a mixed C/T chromatogram peak at codon 41. At structured 6-month follow-up the patient remained relapse-free on glucocorticoids. The genetic finding nevertheless supported the diagnosis. Diagnostic difficulty arises from clinical heterogeneity. A practical pathway emerges: recognition of relapsing polychondritis and infection presentations, evaluation of macrocytosis and cytopenias, bone-marrow examination for precursor vacuoles, UBA1 sequencing with adequate analytic sensitivity, and exclusion of mimics. Glucocorticoids are first-line; steroid-sparing options-interleukin-1 and interleukin-6 inhibitors, Janus kinase inhibitors, and allogeneic hematopoietic stem cell transplantation-are selected by phenotype, severity, and transplant eligibility. VEXAS syndrome should be suspected in older adults with refractory inflammation and unexplained cytopenias. Early recognition of marrow vacuolization and UBA1 sequencing with adequate analytic sensitivity may shorten diagnostic delay and facilitate risk-adapted treatment.

Borrelia miyamotoi Fukunaga (Spirochaetales: Spirochaetaceae), the etiological agent of hard tick relapsing fever, has been detected at low prevalence in Ixodes spp. (Acari: Ixodidae) ticks from the Northern Hemisphere. Genetically distinct populations of B. miyamotoi have been described across continents and among Ixodes tick species distributed within continents. Within the eastern United States, a previous study identified two B. miyamotoi genotypes infecting Ixodes scapularis Say (Acari: Ixodidae). Here, we expand upon that work by developing a new multiplex PCR amplicon sequencing assay to differentiate B. miyamotoi genotypes (Am-East-1 and Am-East-2), and we use the new assay to differentiate genotypes in an expanded sample of 186 B. miyamotoi ticks collected from 17 eastern states. All 80 infections derived from the Northeast (Delaware, Massachusetts, Maryland, Maine, New Hampshire, and Vermont) or northern states in the Southeast region (North Carolina and Virginia) were identified as Am-East-1. Among the 106 B. miyamotoi infections identified in I. scapularis from the Ohio Valley (Illinois, Indiana, Kentucky, Ohio, and West Virginia), Upper Midwest (Michigan, Minnesota, and Wisconsin), or Northern Rocky Mountains and Plains (Nebraska) regions, 10 (9.4%) were characterized as Am-East-1 and 96 (90.6%) were characterized as Am-East-2. We also identified a new B. miyamotoi genotype (Am-IxKi1) in a single I. keiransi Beati, Nava, Venzal, & Guglielmone (Acari: Ixodidae) collected from Virginia.

In the southwestern United States, the occurrence and potential for disease spread of Tick-Borne Relapsing Fever (TBRF) has been studied. In Florida, Borrelia pathogens that cause TBRF have only been found in two domestic dogs (Canis lupus familiaris), yet the soft tick vector, Ornithodoros turicata americanus, is commonly found throughout the state. The goal of our study was to provide the first large-scale investigation of this disease system in the southeastern US. Our objectives were to: 1) describe the occurrence and prevalence of Borrelia spp. in ticks found throughout their distribution; and 2) phylogenetically describe the pathogen species compared to other isolates of B. turicatae. We pooled ticks by sample location and extracted DNA from over 3,000 ticks systematically collected throughout Florida. Conventional PCR was used with a genus-wide IGS primer to detect any Borrelia spp. present in the ticks. We discovered a low but detectable prevalence (7/745; 0.94%) of the pathogen within localized foci, which could present an epidemiological risk to humans and companion animals in those areas. We Sanger sequenced the 7 pools that were positive for Borrelia spp. and created a phylogenetic tree with our samples and 27 previously described isolates. Our tree showed clustering of our samples into two distinct clades, one that fit with Texas isolates and one that was entirely distinct. We hypothesized that a combination of biogeographic and host influences may be the driving force behind the history of Borrelia turicatae in Florida. Future research is needed to improve our understanding of the drivers of pathogen occurrence and the phylogeography of this species. By understanding the occurrence and phylogenetics of Borrelia turicatae in the state, we can better comprehend and mitigate the risk of this neglected vector-borne disease for humans and companion animals in Florida.

Borrelia miyamotoi is an emerging relapsing fever spirochete transmitted by Ixodes spp. ticks that serve as vectors for other human pathogens, including the agents of Lyme disease. To date, an animal model to study tick-borne B. miyamotoi infection and pathology has not been reported. Here, we describe the development of a laboratory mouse model of infection using clinical isolate CT14D4 derived from the blood of a Connecticut resident with disseminated Lyme disease. Genomic analysis revealed that the CT14D4 genome was similar to other B. miyamotoi strains isolated from Ixodes scapularis ticks in the eastern United States. We show that CT14D4 can be propagated in mice by needle inoculation and through a tick-mouse infection cycle. Relapsing spirochetemia was observed in wild-type (WT), Myd88 [-/-], and splenectomized mice, all of which eventually cleared the infections. In contrast, Rag1 [-/-] mice lacking B and T cells remain persistently bacteremic. WT mice that had cleared CT14D4 infection are resistant to reinfection with this B. miyamotoi strain. Spirochetes were visualized in several organs after perfusion fixation of infected Rag1 [-/-] mice, including the brain, with histopathology revealing extramedullary hematopoiesis and inflammatory infiltrates that were most pronounced in the liver. WT mice exhibited similar but milder pathology during periods of bacteremia. These studies provide a useful model to study hard-tick relapsing fever pathogenesis and disease.