Aetiologies of bacterial tick-borne febrile illnesses in humans in Africa: diagnostic limitations and the need for improvement.

Tick-borne febrile illnesses caused by pathogens like Anaplasma spp., Bartonella spp., Borrelia spp., Ehrlichia spp., Coxiella burnetii, Francisella tularensis, and Rickettsia spp., are significant health concerns in Africa. The epidemiological occurrence of these pathogens is closely linked to the habitats of their vectors, prevalent in rural and semi-urban areas where humans and livestock coexist. The overlapping clinical presentations, non-specific symptoms, and limited access to commercially available in vitro diagnostics in resource-limited settings exacerbate the complexity of accurate diagnoses. This review aimed to systematically extract and analyze existing literature on tick-borne febrile illnesses in Africa, highlighting the diagnostic challenges and presenting an up-to-date overview of the most relevant pathogens affecting human populations. A comprehensive literature search from January 1990 to June 2024 using databases like PubMed, Cochrane Library, Science Direct, EMBASE, and Google Scholar yielded 13,420 articles, of which 70 met the inclusion criteria. Anaplasma spp. were reported in Morocco, Egypt, and South Africa; Francisella spp. in Kenya and Ethiopia; Ehrlichia spp. in Cameroon; Bartonella spp. in Senegal, Namibia, South Africa, and Ethiopia; Borrelia spp. in Senegal, Gabon, Tanzania, and Ethiopia; Coxiella burnetii in 10 countries including Senegal, Mali, and South Africa; and Rickettsia spp. in 14 countries including Senegal, Algeria, and Uganda. Data were analyzed using a fixed-effect model in R version 4.0.1 and visualized on an African map using Tableau version 2022.2. This review highlights the urgent need for improved diagnostics to better manage and control tick-borne febrile illnesses in Africa.

Effects of steroids on super-refractory status epilepticus in tick-borne meningoencephalitis.

We report a unique case of super-refractory status epilepticus (SRSE) secondary to tick-borne encephalitis (TBE) to evaluate the therapeutic challenges and potential benefits of steroid treatment in this context. A previously healthy 31-year-old woman was admitted to the hospital with fever, headache, vertigo, and meningismus, ultimately diagnosed with TBE. Despite empirical antimicrobial treatment, the patient's condition deteriorated, leading to coma and SRSE. Various antiseizure medications and sedatives were administered without sustained success. Steroid treatment was initiated due to elevated intracranial pressure and persistent seizure activity. Following the administration of dexamethasone, electrographic status epilepticus resolved, though the patient developed clinical signs of increased intracranial pressure necessitating decompressive craniectomy. The patient's condition stabilized with a combination of antiseizure medicazions. Despite cessation of SRSE, the patient remained in a minimally conscious state at discharge, showing only gradual improvement over time. The use of steroids in TBE is controversial, with limited reports of potential benefits. In this case, steroid administration coincided with the cessation of SRSE, and authors explore its potential benefit considering its immunomodulatory effects.

Surveillance data from 2011-2020 indicate a lower risk of Lyme disease in the USA in even-numbered years.

From 2011-2020 the number of reported cases of Lyme disease in the USA was lower in each even-numbered year compared with the preceding odd-numbered year. This observation suggests that fewer nymphal stage Ixodes scapularis ticks infected with Borrelia burgdorferi were present during even-numbered years in locations where people spend time.

Tick control prevents carcass condemnations in labs caused by Anaplasma ovis.

Ovine anaplasmosis is causing relevant economic losses in Spain due to icteric carcass condemnation in lambs. Anaplasma ovis infection occurs through grazing sheep that transfer ticks to their offspring. This study compared the efficacy of deltamethrin and cypermethrin pour-on treatments for tick control. A total of 250 PCR A. ovis-positive ewes and their offspring were divided into 5 groups. Group A (50 ewes/50 lambs) was kept as an untreated control group. In groups B (50/50) and C (45/93), the lambs were treated with deltamethrin pour-on and cypermethrin pour-on, respectively, one week after birth. In groups D (50/75) and E (51/68), the ewes were treated with cypermethrin pour-on and deltamethrin pour-on one week before the estimated parturition. External parasite assessment and A. ovis PCR were conducted before treatment and at 21 and 42 days post-treatment. Ewes were checked weekly for tick-detection until weaning. Lamb carcasses were examined at the slaughterhouse. Riphicephalus sanguineus sensu lato ticks were found in ewes throughout the study, with only one tick found in a control group lamb. Three lambs tested positive for A. ovis during the trial, with one condemnation at the abattoir due to jaundice. However, no significant differences were observed between treatment groups. Overall, a significant decrease in infected animals and condemned carcasses was observed compared to previous years, suggesting that deltamethrin and cypermethrin prevent A. ovis transmission from dams to lambs. Further studies are needed to confirm synthetic pyrethroids' effectiveness in controlling tick infestation and averting A. ovis transmission to lambs.

[Changes in the Genome of the Tick-Borne Encephalitis Virus during Cultivation].

The tick-borne encephalitis virus (TBEV) strain C11-13 (GenBank acc. no. OQ565596) of the Siberian genotype was previously isolated from the brain of a deceased person. TBEV C11-13 variants obtained at passages 3 and 8 in SPEV cells were inoculated into the brains of white mice for subsequent passages. Full genome sequences of all virus variants were analyzed by high-throughput sequencing. A total of 41 single nucleotide substitutions were found to occur mainly in the genes for the nonstructural proteins NS3 and NS5 (GenBank MF043953, OP902894, and OP902895), and 12 amino acid substitutions were identified in the deduced protein sequences. Reverse nucleotide and amino acid substitutions were detected after three passages through mouse brains. The substitutions restored the primary structures that were characteristic of the isolate C11-13 from a human patient and changed during the eight subsequent passages in SPEV cells. In addition, the 3'-untranslated region (3'-UTR) of the viral genome increased by 306 nt. The Y3 and Y2 3'-UTR elements were found to contain imperfect L and R repeats, which were probably associated with inhibition of cellular XRN1 RNase and thus involved in the formation of subgenomic flaviviral RNAs (sfRNAs). All TBEV variants showed high-level reproduction in both cell cultures and mouse brains. The genomic changes that occurred during successive passages of TBEV are most likely due to its significant genetic variability, which ensures its efficient reproduction in various hosts and its broad distribution in various climatic zones.

Development and evaluation of a TaqMan® real-time PCR assay for species-specific detection of Ehrlichia canis.

The aim of this work was to develop a real-time PCR assay with a TaqMan® probe that detects a species-specific part of the 16S rDNA gene of Ehrlichia canis. Canine blood samples (n = 207), collected and tested by a conventional PCR assay within a study conducted by De Salvo et al., were simultaneously analyzed with the novel designed real-time PCR, and the results of both assays were compared. The agreement between the two methods was 97.6 % with a kappa value of 0.92186. Hereby, the standard error was 0.034416 and the 95 % confidence interval from 0.8544 to 0.98931. While the conventional PCR assay showed false negative results (2.42 %; 5/207), the real-time PCR assays showed a specificity of 100 %. The results of the current study showed that the developed assay presents sensitivity and specificity for the detection of E. canis in blood samples, adding a new tool for the diagnosis of this pathogen.

Ixodes ricinus tick presence is associated with abiotic but not biotic factors.

Species composition and densities of wild ungulate communities in Europe have changed over the last decades. As ungulates play an important role in the life-cycle of the tick species Ixodes ricinus, these changes could affect both the life-cycle of I. ricinus and the transmission of tick-borne pathogens like Borrelia burgdorferi (s.l.) and Anaplasma phagocytophilum. Due to morphological and behavioural differences among the ungulate species, these species might have different effects on the densities of questing I. ricinus, either directly through a bloodmeal or indirectly via the impact of ungulates on rodent numbers via the vegetation. In this study, we aimed to investigate these direct and indirect effects of five different ungulate species, fallow deer (Dama dama), roe deer (Capreolus capreolus), red deer (Cervus elaphus), moose (Alces alces), and wild boar (Sus scrofa), on the presence and abundance of I. ricinus ticks. In the summer of 2019, on 20 1 × 1 km transects in south-central Sweden that differed in ungulate community composition, we collected data on tick presence and abundance (by dragging a cloth), ungulate community composition (using camera traps), vegetation height (using the drop-disc method), temperature above field layer and rodent abundance (by snap-trapping). Using generalized linear mixed models we did not find any associations between vegetation height and tick presence/abundance or ungulate visitation frequencies, or between ungulate visitation frequencies and the presence/abundance of questing I. ricinus. The power of our analyses was, however, low due to very low tick and rodent numbers. We did find a negative association between adult ticks and air temperature, where we were more likely to find adult ticks if temperature in the field layer was lower. We conclude that more elaborate long-term studies are needed to elucidate the investigated associations. Such future studies should differentiate among the potential impacts of different ungulate species instead of treating all ungulate species as one group.

Incidence of symptomatic Borrelia burgdorferi sensu lato infection in Romania, 2018-2023.

BACKGROUND: Lyme borreliosis (LB), caused by Borrelia burgdorferi sensu lato (Bbsl), is the most common tick-borne disease in Europe. Although public health surveillance for LB has been conducted in Romania since 2007, the extent of under-detection of Bbsl infections by LB surveillance has not been estimated. We therefore estimated the under-detection of symptomatic Bbsl infections by LB surveillance to better understand the LB burden in Romania. METHODS: The number of incident symptomatic Bbsl infections were estimated from a seroprevalence study conducted in six counties (population 2.3 M) and estimates of the symptomatic proportion and duration of persistence of anti-Bbsl immunoglobulin G (IgG) antibodies. The number of incident symptomatic Bbsl infections were compared with the number of surveillance-reported LB cases to derive an under-detection multiplier, and then the under-detection multiplier was applied to LB surveillance data to estimate the incidence of symptomatic Bbsl infection from 2018 to 2023. RESULTS: We estimate that there were 1968 individuals with incident symptomatic Bbsl infection in the six counties where the seroprevalence study was conducted in 2020, compared with the 187 surveillance-reported LB cases, resulting in an under-detection multiplier of 10.5 (i.e., for every surveillance-reported LB case, there were 10.5 symptomatic incident Bbsl infections). The incidence of symptomatic Bbsl infection in the six counties was 86.9/100,000 population in 2023, similar to the incidence in 2018-2020 (86.0) and higher than in 2021-2022 (40.3). CONCLUSIONS: There is a higher incidence of symptomatic Bbsl infection than is reported through public health surveillance for LB in Romania. Additional efforts are needed to strengthen disease prevention and address the important public health problem of LB.

Prevalence of Tick Infection with Bartonella in China: A Review and Meta-analysis.

OBJECTIVE: Bartonellosis is a global vector-borne zoonosis caused by Bartonella, a genus of intracellular Gram-negative bacteria. It is one of 14 emerging infectious diseases that have recently been identified in China, and the prevalence varies by region. A more in-depth understanding is needed regarding the role and influencing factors of ticks in the transmission of Bartonella, including the infection rate of ticks with Bartonella in different regions. This study explored the prevalence of Bartonella in ticks and the factors that influence it. METHODS: Databases (PubMed, Embase, Elsevier ScienceDirect, Cochrane Library, Web of Science, CNKI, VIP, CBM, and WanFang) were searched to review the preliminary research on Bartonella-carrying ticks in China. RESULTS: We identified and included 22 articles. Bartonella infection rates in ticks varied from 0 to 22.79% examined by the included studies. Our meta-analysis revealed that the prevalence of Bartonella in ticks was 3.15% (95% CI: 1.22 - 5.82%); the prevalence was higher in parasitic ticks (4.90%; 95% CI: 1.39 -10.14%) than ticks seeking hosts (1.42%; 95% CI: 0.62 - 2.50%) (P = 0.047). CONCLUSION: The prevalence of Bartonella in the southern region of China (6.45%) was higher than that in the northern region (1.28%) (P = 0.030). Knowledge of ticks' vectors and reservoir competence is crucial to reduce the disease burden.

TaqMan qPCR and IgM Detection in Samples of Patients with Tick-Borne Encephalitis Virus Infection in Northeast China.

Purpose: Tick-borne encephalitis virus (TBEV) infections result in severe central nervous system diseases in humans across Asia and Europe. In China, cases of tick-borne encephalitis are primarily caused by the Far East subtype of TBEV, which exhibits a distinct disease course compared to other extensively studied subtypes. However, there is limited knowledge regarding the nucleic acid and serological diagnostic characteristics of patients infected with the TBEV in China, which is the focus of investigation in the present study. Methods: This study established a TaqMan qPCR approach to detect TBEV RNA in the serum with optimal specificity, sensitivity, and precision. Using TaqMan qPCR and ELISA assay for TBEV IgM detection, serum samples from 63 hospitalized patients bitten by ticks in Northeast China were investigated for diagnostic characteristics. Results: Twenty-five patients were positive for viral RNA; nineteen patients were positive for IgM, and nine were positive for both viral RNA and IgM. Through comparative analysis, TBEV RNA copies were negatively correlated with the virus incubation period. IgM levels were positively correlated with the clinical symptom scores of patients. The severity of clinical symptoms and the length after the tick bite could be used to predict the IgM occurrence. Furthermore, IgM levels and viral RNA copies were not correlated in double-positive patients. Conclusion: Both nucleic acid and serological detection methods exhibited distinct windows for detecting TBEV infection, with some overlap, and were associated with specific correlated factors. This study provided novel insights into the diagnosis and course of TBEV-induced tick-borne encephalitis in China.

Procalcitonin levels in severe fever with thrombocytopenia syndrome patients: a retrospective investigation in Anhui, China.

INTRODUCTION: This work aim to evaluate the association of procalcitonin (PCT) levels with disease severity and prognosis in severe fever with thrombocytopenia syndrome (SFTS) patients. METHODOLOGY: The medical records of 158 confirmed SFTS patients at two hospitals were reviewed. The patients were divided into survival group and nonsurvival group according to outcomes. Additionally, to assess mortality rates at different PCT levels, patients were divided into two groups, PCT < 0.25 ng/mL and PCT ≥ 0.25 ng/mL. RESULTS: Among the 158 confirmed SFTS patients, 26 died; the case fatality rate was 16.46%. PCT data were available for 132 of these patients; 66 were in the PCT < 0.25 ng/mL group, and 66 were in the PCT ≥ 0.25 ng/mL group. The SFTS patients had abnormal results on routine blood tests, indicating varying degrees of thrombocytopenia and leukopenia, and most patients presented with multiple organ dysfunction. The PCT level of the nonsurvival group was significantly higher than that of the survival group (p < 0.01). Additionally, the mortality of the PCT ≥ 0.25 ng/mL group was significantly higher than that of the PCT < 0.25 ng/mL group (p < 0.01); mortality increased sharply ( ≥ 25%) when the PCT level exceeded 0.1 ng/mL. CONCLUSIONS: PCT levels in SFTS patients are closely related to the severity and prognosis of their illness. The serum PCT level is a promising predictor of mortality and severity in SFTS patients when considered in combination with clinical data and other laboratory tests.

Knowledge, attitudes and behaviour towards ticks and tick-borne diseases-A survey among Lyme borreliosis cases in Bavaria in 2019.

Lyme borreliosis (LB) is the most common tick-borne disease (TBD) in Germany. In Bavaria, the average annual incidence of reported cases was 34.3 cases per 100,000 inhabitants between 2013 and 2020, although case numbers were presumed to be substantially higher. Since no vaccine against LB is currently available, prevention focuses on individual protection measures. This study aims to address knowledge, attitudes, and behaviours among LB cases, a population group at increased exposure to ticks, tick bites and repeated infections. We invited Bavarian LB cases reported between weeks 23 and 35 in 2019 to participate in a questionnaire study. Questions included socio-demographic characteristics, experiences with TBDs, potential tick exposures, details of the recent episode of LB, and knowledge, attitudes, and behaviours regarding TBDs and protection measures. Among the 377 participants, 300 were adults/adolescents, 77 were children (<14 years). Two third resided in rural areas. Although mostly well informed, a significant proportion of participants did not know or were misinformed about availability of repellents (48.5 %), risk of LB in their district (24.9 %), ticks not falling from trees (22.1 %) and non-availability of vaccination against LB (20.9 %). Even though a majority perceived checking for ticks after spending time outdoors, wearing long clothes, wearing closed shoes and tucking pants in socks as effective protection measures against tick bites, a much lower proportion applied those measures frequently (proportions perceived vs. applied: 99.2 % vs. 72.1%; 93.8 % vs. 40.2 %, 88.8 % vs. 51.1 % and 85.4 % vs. 16.8 %, respectively). Identified lack of knowledge or misconception regarding risk factors, availability of protection measures and tick behaviour may hamper application of recommended protection measures. There appeared to be a discrepancy between perceived effectiveness and frequency of application of protection measures. Addressing identified gaps in education campaigns, specifically targeting people living in rural areas, and utilising physician-patient interactions for education are promising entry points to increase awareness and prevent TBDs. Moreover, motivators and barriers for the application of preventive behaviour should be subject of future studies.

Prevalence of Anaplasma Spp. and Theileria Spp. Antigens and Antibodies in Housed and Grazing Korean Indigenous Cattle.

Background: Infection with tick-borne pathogens (TBPs) causes anemia, jaundice, and growth retardation in cattle. Many studies have conducted antigen (Ag) tests for major TBPs, such as Anaplasma spp. and Theileria spp., in Korean indigenous cattle (KIC); however, few studies have analyzed antibodies (Ab) against these pathogens. Materials and Methods: This study simultaneously tested 15 housed cattle raised indoor for over a year and 67 grazing cattle for Anaplasma spp. and Theileria spp. Ag using polymerase chain reaction analysis and Ab using enzyme-linked immunosorbent assay. Results: The A. phagocytophilum was detected in 3 housed cattle (20.0%) and 30 grazing cattle (44.8%), whereas the T. orientalis was detected in 3 housed cattle (20.0%) and 54 grazing cattle (80.6%). The positivity rates for Anaplasma spp. Ab did not differ significantly between housed and grazing cattle (4 out of 15 [93.3%] and 55 out of 67 [80.0%], respectively). The positivity rates for Theileria spp. Ab were higher in grazing cattle than in housed cattle (21 of 67 [31.3%] and 0 out of 15 [0.0%], respectively) (P < 0.01). No difference was observed between the frequency of grazing and the abundance of Ab against either pathogen. Meanwhile, as a result of comparing the detection of pathogen Ag and Ab, Anaplasma spp. showed the highest proportions of 73.3% and 47.8% in Ag (-)/Ab (+) for housed cattle and grazing cattle, respectively. Theileria spp. showed the highest rates of 80.0% in Ag (-)/Ab (-) for housed cattle and 52.2% in Ag (+)/Ab (-) for grazing cattle. Conclusions: This is the first study to determine the impact of antibody abundance against Anaplasma spp. and Theileria spp. on antigen prevalence in KIC.

Identification and characterization of Jingmen tick virus from Rhipicephalus microplus in Hunan, China.

Jingmen tick virus (JMTV) is a tick-borne pathogen known to affect human beings, characterized by a segmented genome structure that defies the conventional understanding of the Flaviviridae family. In the present study, we employed metagenomic analysis to screen for tick-borne viruses in Hunan Province, China, and identified five JMTV variants with complete genomes from Rhipicephalus microplus ticks sampled from cattle. These viral strains exhibited the highest sequence similarity to JMTV isolates previously reported in Hubei Province, China. However, evidence of genomic reassortment was detected, particularly with the S2 segment showing greater similarity to the strains from Japan. Phylogenetic analysis demonstrated that JMTV strains cluster predominantly based on their geographic origin. In agreement with the homology data, the S1, S3, and S4 segments of the strains identified in this study grouped with those from Hubei Province, while the S2 segment displayed a distinct topological structure. Moreover, JMTV displayed limited replication in mammal-derived cells, but thrived in tick-derived cell lines. In addition to the commonly used R. microplus-derived BME/CTVM23 cells, we found that JMTV also proliferated robustly in both Ixodes scapularis-derived ISE6 and Ixodes ricinus-derived IRE/CTVM19 cells, offering new avenues for in vitro production of the virus. In summary, this study expands the known geographic distribution and genetic diversity of JMTV, providing valuable insights into its epidemiology and potential for in vitro cultivation.

Detection of Neoehrlichia mikurensis in 11 persons who attribute their persistent health complaints to a tick-borne disease.

BACKGROUND: Neoehrlichia mikurensis infections can cause symptomatic disease, particular among immunosuppressed persons. Long-lasting asymptomatic carriage of N. mikurensis may be common in endemic areas. This study explores possible associations between carriage of N. mikurensis DNA and persistent health complaints in persons who attribute their symptoms to a tick-borne disease. METHODS: Eleven persons tested positive for N. mikurensis DNA by PCR in a study cohort of 285 persons reporting persistent health complaints. The 11 persons were tested again in a follow-up sample. Oral doxycycline treatment was given if the confirmatory PCR-test was positive. Treatment response was assessed by telephone interview. Demographics, clinical manifestations, tick exposure, physical health, somatic symptom burden and fatigue were compared to persons with negative N. mikurensis PCR (controls, N = 274). RESULTS: Six persons had detectable N. mikurensis DNA in a follow-up sample up to 9.5 months after the index sample. Seven persons (one without a positive confirmative test) received doxycycline treatment. Three reported symptom restitution after completed antibiotic treatment. However, their symptoms were not clearly attributed to infection by N. mikurensis. We did not find any significant differences between infected persons and non-infected controls regarding their clinical manifestations and health burdens. CONCLUSIONS: We corroborate previous evidence of long-term carriage of N. mikurensis, but cannot infer that to be causative of persistent health complaints.

Administration of Corticosteroids for Prompt Suppression of Cytokine Storm in Severe Cases of Japanese Spotted Fever.

Japanese spotted fever (JSF) is a tick-borne disease caused by Rickettsia japonicaand primarily affects the warmer coastal areas of Japan. Early treatment with tetracycline antibiotics is crucial to prevent severe complications, such as pneumonia, meningitis, disseminated intravascular coagulation (DIC), and systemic inflammatory response syndrome. An 83-year-old man with hypertension, chronic kidney disease, and hyperuricemia presented with DIC and subsequently developed septic shock. Polymerase chain reaction confirmed JSF caused by R. japonica. Initial treatment with ceftriaxone was ineffective, leading to a switch to intravenous minocycline and levofloxacin. Considering the high levels of C-reactive protein, procalcitonin, ferritin, and soluble interleukin-2 receptor, intravenous hydrocortisone (200 mg/day) was administered to control the cytokine storm. On day 4, the patient's condition improved significantly, with increased blood pressure, reduced DIC markers, and decreased levels of inflammatory cytokines, including interleukin-6 and tumor necrosis factor-α. The patient's recovery continued, and he was transferred to a chronic care hospital. Severe JSF cases are primarily driven by a cytokine storm caused by an excessive immune response. Early administration of corticosteroids along with antibiotics effectively suppressed the cytokine storm in this case. Reports have shown mixed results, indicating the need for further research to determine the optimal type, dosage, and duration of corticosteroid treatment.

Crimean-Congo Hemorrhagic Fever Virus: An Emerging Threat in Europe with a Focus on Epidemiology in Spain.

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne disease transmitted by ticks of the genus Hyalomma and caused by a virus of the Nairoviridae family. In humans, the virus can generate different clinical presentations that can range from asymptomatic to mild illness or produce an hemorrhagic fever with a mortality rate of approximately 30%. The virus pathogenicity and the lack of effective treatment or vaccine for its prevention make it an agent of concern from a public health point of view. The main transmission route is tick bites, so people most exposed to this risk are more likely to become infected. Another risk group are veterinarians and livestock farmers who are in contact with the blood and other fluids of animals that are mostly asymptomatic. Finally, due to its first phase with a non-characteristic symptomatology, there exists a risk of nosocomial infection. It is endemic in Africa, the Balkans, the Middle East, and those Asian countries south of the 50th parallel north, the geographical limit of the main vector. Recently, autochthonous cases have been observed in areas of Europe where the virus was not previously present. Human cases have been detected in Greece, Bulgaria, and Spain. Spain is one of the most affected countries, with a total of 17 autochthonous cases detected since 2013. In other countries, such as France, the virus is present in ticks and animals but has not spread to humans. A high-quality epidemiological surveillance system in these countries is essential to avoid the expansion of this virus to new areas and to limit the impact of current cases.

Clinical Evaluation of the VirClia IgM/IgG Chemiluminescence Tests for the Diagnosis of Tick-Borne Encephalitis in an Endemic Part of Norway.

The aim of this study was to evaluate the clinical usefulness of VirClia IgM/IgG single-assay chemiluminescence tests for the diagnosis of tick-borne encephalitis (TBE) in an endemic part of Norway. Patients hospitalized at Vestfold or Telemark Hospitals with suspected infection in the central nervous system (CNS) in the period between May 2021 and December 2023 were included, with 85 TBE cases identified. The VirClia IgM assay was positive in the initial serum sample in 75/85 cases, giving a sensitivity of 88.2% (95% CI, 79.4-94.2). The ReaScan TBE IgM rapid test was positive in 80/85 cases, with an estimated sensitivity of 94.1% (95% CI, 86.8-98.1). Vaccine breakthrough infections were the predominant cause of non-reactive IgM cases. The calculated specificity for the VirClia IgM was 95.8% (95% CI, 92.5-98.0). In conclusion, the sensitivity of the VirClia IgM was non-inferior to the ReaScan TBE IgM rapid test. However, isolated IgM reactive results must be interpreted with caution, since false-reactive results occur.

Rapid Increase in Seroprevalence of Borrelia burgdorferi Antibodies among Dogs, Northwestern North Carolina, USA, 2017-20211.

We evaluated spatial-temporal risk for Lyme disease in northwestern North Carolina, USA, by using individual-level canine Borrelia burgdorferi seroprevalence data collected during 2017-2021 at routine veterinary screenings for tickborne diseases. Seroprevalence in dogs increased from 2.2% (47/2,130) in 2017 to 11.2% (339/3,033) in 2021. The percentage of incident seropositivity increased from 2.1% (45/2,130) in 2017 to 7.6% (231/3,033) in 2021. Exploratory geographic analyses found canine seroprevalence shifted from clustered (2017, Moran's I = 0.30) to dispersed (2021, Moran's I = -0.20). Elevation, slope, aspect, and forest land cover density were associated with canine seroprevalence within various household buffer regions in 2017. Slope was associated with seroprevalence at the household level in 2021. Results support the use of individual-level canine seroprevalence data for monitoring human risk for Lyme disease. Establishing sentinel veterinary clinics within Lyme disease-emergent communities might promote prevention and control efforts and provide opportunities for educational and behavioral interventions.

Molecular detection of Rickettsia aeschlimannii, Candidatus Rickettsia shennongii, Rickettsia sp. and Coxiella burnetii in ticks collected from camels.

Tick-borne bacteria of the genera Rickettsia and Coxiella cause several emerging veterinary and human infectious diseases. Ticks of the genus Hyalomma are medically important vectors due to their potential role in the transmission of pathogens to vertebrate hosts. There is an inadequate knowledge on tick-borne Rickettsia spp. and Coxiella spp. in ticks infesting transhumant camels in Pakistan. In this study, we conducted a molecular survey for screening of Rickettsia spp. and Coxiella spp. in ticks infesting camels. Seven hard tick species including Hyalomma dromedarii, Hyalomma anatolicum, Hyalomma scupense, Hyalomma isaaci, Hyalomma turanicum, Hyalomma asiaticum, and Rhipicephalus sanguineus s.l were confirmed on camels in three distinct physiographic regions of Khyber Pakhtunkhwa, Pakistan. A subset of morphologically identified ticks were subjected to molecular assays for the genetic characterization of ticks and the detection and genetic characterization of Rickettsia and Coxiella species using standard genetic markers. Ticks screened for pathogens resulted in the detection of Rickettsia aeschlimannii and Candidatus Rickettsia shennongii and Coxiella burnetii. The molecular analysis further reveals the presences of an undetermined Rickettsia aeschlimannii-like species, that is making a distinct phylogenetic clade with R. aeschlimannii. The detection of pathogens in camel ticks poses potential health hazards as these ticks frequently bites humans. Molecular screening of Rickettsia spp. and Coxiella spp. associated with camel ticks is a preliminary step toward the surveillance of evaluating their zoonotic threats in the region.