Characteristics of Hard Tick Relapsing Fever Caused by Borrelia miyamotoi, United States, 2013-2019

Borrelia miyamotoi in vivo antigenic variation demonstrated by serotype reisolations from infected mice

Relapsing fever Borrelia (RFB) employs antigenic variation to alter its surface protein structure in response to host immune pressure. This process occurs by the single translocation of archived variable major protein (Vmp) pseudogenes into a vmp expression locus. Borrelia miyamotoi, phylogenetically grouped with RFB, has the genetic makeup for antigenic variation, but it has not been determined whether B. miyamotoi can create new variant serotypes in vivo. We inoculated mice with a non-clonal parental B. miyamotoi CT13-2396 strain with a known Vmp majority serotype with spirochete isolation at various days post-infection. The vmp that determined the reisolated variant serotype was identified by PCR of the expression locus followed by DNA sequencing of the amplified product. For each mouse reisolate, new variants replaced the parent majority serotype. Moreover, some mice produced additional variant reisolates days apart, indicative of the presentation seen in relapsing fever infections. Infection of mice with a clonal population resulted in the elimination of the inoculated serotype and isolation of new variants. Mouse serum obtained following infection revealed IgM antibodies reactive to the parent Vmp serotype, suggesting that the immune response eliminated or greatly reduced the majority population. These results demonstrated that B. miyamotoi reisolated from infected mice exhibited serotype populations differing from the inoculated strain, indicating the spirochetes underwent antigenic variation to evade the host's immune response. However, whether the observed variation occurred by way of outgrowth of minority populations or by translocation of archived pseudogenes to the expression locus creating new variants awaits further study.

Prevalence of Babesia microti Co-Infection with Other Tick-Borne Pathogens in Pennsylvania

Babesia microti is a protozoan that infects red blood cells, causing hemolytic anemia and flu-like symptoms in humans. Understanding co-infections is crucial for the better diagnosis, treatment, and management of tick-borne diseases. This study examined the prevalence of Babesia microti co-infection with other prevalent tick-borne pathogens in Pennsylvania. The dataset acquired from the Dr. Jane Huffman Wildlife Genetics Institute included passive surveillance data from Ixodes spp. from 2021 to 2023. Submitted ticks were screened for tick-borne pathogens using species-specific TaqMan qPCR. Of the 793 B. microti-positive ticks pulled for analysis, 65.0% were co-infected with other pathogens (n = 516). Notably, 60.9% of the B. microti-positive ticks were co-infected with Borrelia burgdorferi, 10.2% with Anaplasma phagocytophilum Ap-ha, and 7.5% carried a triple co-infection with B. burgdorferi and A. phagocytophilum Ap-ha. The rates of B. microti infection and its co-infections are on the rise, with patterns observed in Pennsylvania and other regions of the USA. While other studies have collected both nymphal and adult ticks to screen for co-infections in Pennsylvania, our study stood out as a unique contribution to the field by focusing exclusively on B. microti-positive ticks. The continued monitoring of tick-borne co-infections is vital to prevent misdiagnosis and ensure effective treatment regimens.

Tick-Borne Diseases and Pregnancy: A Narrative Review Evaluating Pregnancy Complications Caused by Tick-Borne Diseases

Ticks are vectors of public health concern because the pathogens they transmit can cause detrimental diseases in humans. Lyme disease, tick-borne relapsing fever, human granulocytic anaplasmosis, Rocky Mountain spotted fever, tick-borne encephalitis, Crimean-Congo hemorrhagic fever, and babesiosis are some of the most common diseases caused by the pathogens transmitted by ticks. The overlap between human activities and tick habitats is growing, contributing to an increase in tick-borne disease cases. Unfortunately, pregnancy as a risk factor for tick-borne diseases is largely ignored. In this narrative review we use case reports, epidemiological studies, and animal studies to evaluate the maternal, pregnancy, and fetal outcomes caused by Lyme disease, tick-borne relapsing fever, human granulocytic anaplasmosis, Rocky Mountain spotted fever, tick-borne encephalitis, Crimean-Congo hemorrhagic fever, and babesiosis during pregnancy.

Lyme Disease Surveillance and Epidemiology in the United States: A Historical Perspective

In the 40 years since Steere and colleagues first described Lyme disease, the illness has increased in incidence and distribution to become the most common vector-borne disease in the United States. Public health officials have developed, implemented, and revised surveillance systems to describe and monitor the condition. Much has been learned about the epidemiology of the illness, despite practical and logistical constraints that have encumbered the collection and interpretation of surveillance data. Future development of automated data collection from electronic health records as a source of surveillance and clinical information will address practical challenges and help answer ongoing questions about complications and persistent symptoms. Robust surveillance will be essential to monitor the effectiveness and safety of future vaccines and other preventive measures.

Acute Meningoencephalitis Associated with Borrelia miyamotoi, Minnesota, USA

Borrelia miyamotoi is an emerging tickborne pathogen that has been associated with central nervous system infections in immunocompromised patients, albeit infrequently. We describe a case-patient in Minnesota, USA, who had meningeal symptoms of 1 month duration. B. miyamotoi infection was diagnosed by Gram staining on cerebrospinal fluid and confirmed by sequencing.