Borrelia lusitaniae Infection Mimicking Headache, Neurologic Deficits, and Cerebrospinal Fluid Lymphocytosis

Lizards and the enzootic cycle of Borrelia burgdorferi sensu lato

Emerging and re-emerging pathogens often stem from zoonotic origins, cycling between humans and animals, and are frequently vectored and maintained by hematophagous arthropod vectors. The efficiency by which these disease agents are successfully transmitted between vertebrate hosts is influenced by many factors, including the host on which a vector feeds. The Lyme disease bacterium Borrelia burgdorferi sensu lato has adapted to survive in complex host environments, vectored by Ixodes ticks, and maintained in multiple vertebrate hosts. The versatility of Lyme borreliae in disparate host milieus is a compelling platform to investigate mechanisms dictating pathogen transmission through complex networks of vertebrates and ticks. Squamata, one of the most diverse clade of extant reptiles, is comprised primarily of lizards, many of which are readily fed upon by Ixodes ticks. Yet, lizards are one of the least studied taxa at risk of contributing to the transmission and life cycle maintenance of Lyme borreliae. In this review, we summarize the current evidence, spanning from field surveillance to laboratory infection studies, supporting their contributions to Lyme borreliae circulation. We also summarize the current understanding of divergent lizard immune responses that may explain the underlying molecular mechanisms to confer Lyme spirochete survival in vertebrate hosts. This review offers a critical perspective on potential enzootic cycles existing between lizard-tick-Borrelia interactions and highlights the importance of an eco-immunology lens for zoonotic pathogen transmission studies.

Italian peninsula as a hybridization zone of Ixodes inopinatus and I. ricinus and the prevalence of tick-borne pathogens in I. inopinatus, I. ricinus, and their hybrids

BACKGROUND

Ixodes inopinatus was described from Spain on the basis of morphology and partial sequencing of 16S ribosomal DNA. However, several studies suggested that morphological differences between I. inopinatus and Ixodes ricinus are minimal and that 16S rDNA lacks the power to distinguish the two species. Furthermore, nuclear and mitochondrial markers indicated evidence of hybridization between I. inopinatus and I. ricinus. In this study, we tested our hypothesis on tick dispersal from North Africa to Southern Europe and determined the prevalence of selected tick-borne pathogens (TBPs) in I. inopinatus, I. ricinus, and their hybrids.

METHODS

Ticks were collected in Italy and Algeria by flagging, identified by sequencing of partial TROSPA and COI genes, and screened for Borrelia burgdorferi s.l., B. miyamotoi, Rickettsia spp., and Anaplasma phagocytophilum by polymerase chain reaction and sequencing of specific markers.

RESULTS

Out of the 380 ticks, in Italy, 92 were I. ricinus, 3 were I. inopinatus, and 136 were hybrids of the two species. All 149 ticks from Algeria were I. inopinatus. Overall, 60% of ticks were positive for at least one TBP. Borrelia burgdorferi s.l. was detected in 19.5% of ticks, and it was significantly more prevalent in Ixodes ticks from Algeria than in ticks from Italy. Prevalence of Rickettsia spotted fever group (SFG) was 51.1%, with significantly greater prevalence in ticks from Algeria than in ticks from Italy. Borrelia miyamotoi and A. phagocytophilum were detected in low prevalence (0.9% and 5.2%, respectively) and only in ticks from Italy.

CONCLUSIONS

This study indicates that I. inopinatus is a dominant species in Algeria, while I. ricinus and hybrids were common in Italy. The higher prevalence of B. burgdorferi s.l. and Rickettsia SFG in I. inopinatus compared with that in I. ricinus might be due to geographical and ecological differences between these two tick species. The role of I. inopinatus in the epidemiology of TBPs needs further investigation in the Mediterranean Basin.

Detection and genetic identification of Borrelia lusitaniae in questing Ixodes inopinatus tick from Tunisia

Background

Until now, there has been limited information on the prevalence and the phylogeny of Borrelia burgdorferi sensu lato in Ixodes ticks in Tunisia, particularly in Ixodes inopinatus.

Methods

The present study aimed to determine the prevalence and the phylogeny of B. burgdorferi s.l., in coexisted I. ricinus and I. inopinatus ticks collected from Northern Tunisia. One hundred questig ticks were collected during winter 2020 by tick-dragging method in Beja gouvernorate located in the north of Tunisia. Real-time PCR panel targeting B. burgdorferi s.l. 23S rRNA gene were performed. Positive DNA samples were subjected to conventional PCRs targeting 457 bp fragment of the Borrelia sp. flagellin (fla) gene using primers FlaF/FlaR. The identified Borrelia sp. isolate underwent partial sequence analysis to determine genospecies and evaluate their phylogenetic position.

Results

The study revealed a prevalence rate of 28% (28/100) for B. burgdorferi sensu lato in the Ixodes ticks. The prevalence rates across tick species and genders did not show significant variations (p > 0.05). Interestingly, the study underlines the coexistence of I. inopinatus and I. ricinus sharing the same geographic areas in Northern Tunisia. Furthermore, DNA of B. lusitaniae was detected in I. inopinatus ticks for the first time in Tunisia. Revealed B. lusitaniae bacterium is similar to previously identified strains in Mediterranean region, but distinct from those isolated exclusively from countries of Eastern and Central Europe, such as Serbia, Romania, and Poland. This study highlights the prevalence of B. burgdorferi s.l. in I. ricinus/I. inopinatus ticks, and reveals B. lusitaniae in I. inopinatus ticks for the first time in Tunisia.

Conclusion

These findings suggest the involvement of I. inopinatus as a potential vector of this pathogenic genospeciess in Tunisia. This may help understanding the ecology of Ixodes ticks, the natural infection and the transmission dynamics of Borrelia species in this country.

Transient headache and neurological deficits with cerebrospinal fluid lymphocytosis syndrome: A comprehensive systematic review of 93 patients from 57 studies

BACKGROUND

Headache with neurologic deficits and cerebrospinal fluid lymphocytosis, previously also termed pseudomigraine with temporary neurologic symptoms and lymphocytic pleocytosis, is a self-limiting syndrome characterized by moderate to severe headache associated with focal neurological deficits occurring in the context of lymphocytosis in the cerebrospinal fluid. As a consequence of its rarity, data regarding headache with neurologic deficits and cerebrospinal fluid lymphocytosis is sparse. Therefore, we conducted this review to analyze data related to 93 patients of headache with neurologic deficits and cerebrospinal fluid lymphocytosis, to characterize their demographics, clinical manifestations, investigations and treatment options.

METHODS

We performed a systematic review of cases reported through PubMed and Google scholar database, using Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Keywords used were 'Headache with Neurologic Deficits and cerebrospinal fluid lymphocytosis', 'Headache with neurologic deficits and cerebrospinal fluid lymphocytosis syndrome'. The quality of the included studies was assessed using the Joanna Briggs Institute Critical Appraisal Tool.

RESULTS

We analyzed a total of 93 cases of headache with neurologic deficits and cerebrospinal fluid lymphocytosis with a mean age of 28.8 years at onset. Seventy patients (75.2%) were adults, while 23 (24.7%) belonged to the pediatric age group. Comparing these groups, mean age at onset was 32.5 years and 14.3 years, respectively. The average duration of follow-up was 11.08 months. Thirty percent of patients experienced relapsing episodes of headache with neurologic deficits and cerebrospinal fluid lymphocytosis symptoms. The most common type of headache reported was unilateral severe throbbing episodic headache. Other associated symptoms included sensory deficit (60%) and motor deficits (54.8%). The least common symptoms were nystagmus and agraphia, which were reported in one patient each. Antiviral agents were a common treatment option in the acute phase (n  =  23 patients [23.6%]), while Flunarizine was the most commonly used agent in the chronic setting (n = 3 patients [3.2%]). While most of the patients had normal brain magnetic resonance imaging, 20 patients had magnetic resonance imaging abnormalities, including (but not limited to) non-specific white matter lesions (eight patients) and meningeal enhancement (six patients). The most common electroencephalographic findings included diffuse and focal slowing. The mean cerebrospinal fluid opening-pressure was 240.5 mmH₂O. Cerebrospinal fluid protein was elevated in 59 (63.4%) patients, with a mean value of 114 mg/dL. Two patients in our cohort were found to have cerebrospinal fluid oligoclonal bands.

CONCLUSION

Headache with neurologic deficits and cerebrospinal fluid lymphocytosis tends to affect young individuals with a slight male predominance. Unilateral severe throbbing episodic headache with associated hemi-paresthesia and hemiparesis were the most common symptoms based on our review. Elevated cerebrospinal fluid opening-pressure can be seen in headache with neurologic deficits and cerebrospinal fluid lymphocytosis syndrome. Early recognition of the syndrome is paramount. Antivirals were found to be among the most widely used treatments in the acute setting. Magnetic resonance imaging of the brain is mostly normal. Diffuse and focal slowing were among the most common electroencephalographic findings. Cerebral flow abnormalities on perfusion scans are not uncommon in headache with neurologic deficits and cerebrospinal fluid lymphocytosis. Prospective studies with a larger sample size are needed to validate our findings and guide the clinical care of these patients.

HaNDL syndrome: a reversible cerebral vasoconstriction triggered by an infection? A case report and a case-based review

Background

The syndrome of transient Headache and Neurological Deficits with cerebrospinal fluid (CSF) Lymphocytosis (HaNDL) is classified among secondary headaches attributed to “non-infectious, inflammatory intracranial disease”. Despite its classification among secondary headaches, the current definition of HaNDL does not contemplate a causal agent. Thus, the aetiology, as well as the pathogenesis of both the headache and the transient focal deficits, remains unknown.

Case presentation

We describe a 29-year-old healthy male developing episodes of thunderclap headaches associated with recurrence of hemiparesis/hemi-paraesthesia; CSF showed lymphocytosis 200/mm³ and increased albumin; brain MRI revealed widespread leptomeningeal enhancement and a non-enhancing, circular diffusion restriction in the splenium of corpus callosum. Screening for neurotropic pathogens detected Epstein-Barr (EBV) DNA in serum and CSF, interpreted as a primary EBV infection once the seroconversion of EBV nuclear antigen (EBNA) IgM to IgG was proven on follow-up. Transcranial Doppler detected, during headache, increased flow velocity in middle cerebral arteries, possibly indicating vasospasm. Oral nimodipine was administered, with prompt clinical recovery, resolution of CSF/MRI abnormalities, and normalization of flow velocities in middle cerebral arteries.

Case-based review

Although the definition of HaNDL does not contemplate a viral trigger or abnormal brain imaging, we found other literature cases of HaNDL associated with direct or indirect signs of CNS infection.

Conclusions

At least in a proportion of patients, a viral aetiology may have a role in HaNDL. Whatever the aetiology, we suggest that the pathogenic mechanism may rely on the (viral or other) agent ultimately triggering cerebral vasoconstriction, which would explain both focal symptoms and headache. Calcium channel blockers might be a therapeutic option.