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We report the detection of Crimean-Congo hemorrhagic fever virus (CCHFV) in Corsica, France. We identified CCHFV African genotype I in ticks collected from cattle at 2 different sites in southeastern and central-western Corsica, indicating an established CCHFV circulation. Healthcare professionals and at-risk groups should be alerted to CCHFV circulation in Corsica.

We conducted surveillance studies in Sinaloa, Mexico, to determine the circulation of tick-borne relapsing fever spirochetes. We collected argasid ticks from a home in the village of Camayeca and isolated spirochetes. Genomic analysis indicated that Borrelia turicatae infection is a threat to those living in resource-limited settings.

We report the detection of Crimean-Congo hemorrhagic fever virus (CCHFV) in Corsica, France. We identified CCHFV African genotype I in ticks collected from cattle at 2 different sites in southeastern and central-western Corsica, indicating an established CCHFV circulation. Healthcare professionals and at-risk groups should be alerted to CCHFV circulation in Corsica.

Human-biting ticks threaten public health in the United States. Registration by the Environmental Protection Agency of products to kill host-seeking ticks or repel ticks contacting humans is indicative of their safety and effectiveness. Unregulated minimum risk products, exempt from Environmental Protection Agency registration and often based on botanical oils, are proliferating in the marketplace, but there is concern about their effectiveness to kill and repel ticks. Evaluations of such products are limited in the published literature. A review showed considerable variability among minimum risk products to kill host-seeking blacklegged ticks, with effectiveness similar to chemical pesticide products for some minimum risk products but minimal impact on the ticks for other products. Evaluations of minimum risk tick repellents have typically focused on individual active ingredients rather than formulated products, which often combine multiple active ingredients. Consumers should be aware that effectiveness to kill and repel ticks can differ among unregulated minimum risk products.

We conducted surveillance studies in Sinaloa, Mexico, to determine the circulation of tick-borne relapsing fever spirochetes. We collected argasid ticks from a home in the village of Camayeca and isolated spirochetes. Genomic analysis indicated that Borrelia turicatae infection is a threat to those living in resource-limited settings.

Human-biting ticks threaten public health in the United States. The blacklegged tick (Ixodes scapularis) is a frequent human-biter and vector of viral, bacterial, and parasitic agents causing human illness, including [...]

We detected Borrelia bavariensis in Ixodes ricinus ticks collected near 2 towns in the United Kingdom. Human B. bavariensis infections have not been reported previously in the country, underscoring the value of tick surveillance to warn of emerging human disease. B. bavariensis should be considered in patients with suspected neuroborreliosis.

We document a case of Rickettsia parkeri rickettsiosis in a patient in Connecticut, USA, who became ill after a bite from a Gulf Coast tick (Amblyomma maculatum). We used PCR to amplify R. parkeri DNA from the detached tick. The patient showed a 4-fold rise in IgG reactive with R. parkeri antigens.

Viruses of the genus Orthonairovirus, family Nairoviridae, include the consequential tick-transmitted pathogens Crimean-Congo hemorrhagic fever virus and Nairobi sheep disease virus, as well as other poorly characterized viruses that have [...]

Monitoring of tickborne diseases is critical for prevention and management. We analyzed 418 ticks removed from 359 patients during 2014–2021 in Marseille, France, for identification and bacteria detection. Using morphology, molecular methods, or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, we identified 197 (47%) Ixodes, 136 (33%) Dermacentor, 67 (16%) Rhipicephalus, 8 (2%) Hyalomma, 6 (1%) Amblyomma, 2 (0.5%) Argas, and 2 (0.5%) Haemaphysalis tick species. We also detected bacterial DNA in 241 (58%) ticks. The most frequent bacterial pathogens were Rickettsia raoultii (17%) and R. slovaca (13%) in Dermacentor ticks, Borrelia spp. (9%) in Ixodes ticks, and R. massiliae (16%) in Rhipicephalus ticks. Among patients who were bitten, 107 had symptoms, and tickborne diseases were diagnosed in 26, including scalp eschar and neck lymphadenopathy after tick bite and Lyme borrelioses. Rapid tick and bacteria identification using a combination of methods can substantially contribute to clinical diagnosis, treatment, and surveillance of tickborne diseases.

We isolated a new orthonairovirus from Dermacentor silvarum ticks near the China–North Korea border. Phylogenetic analysis showed 71.9%–73.0% nucleic acid identity to the recently discovered Songling orthonairovirus, which causes febrile illness in humans. We recommend enhanced surveillance for infection by this new virus among humans and livestock.

We identified Yezo virus infection in a febrile patient who had a tick bite in northeastern China, where 0.5% of Ixodes persulcatus ticks were positive for viral RNA. Clinicians should be aware of this potential health threat and include this emerging virus in the differential diagnosis for tick-bitten patients in this region.

In Corsica, France, 9.1% of livestock serum samples collected during 2014-2016 were found to have antibodies against Crimean-Congo hemorrhagic fever virus (CCHFV), an emerging tickborne zoonotic disease. We tested 8,051 ticks for CCHFV RNA and Nairovirus RNA. The results indicate that Corsica is not a hotspot for CCHFV.

Tickborne diseases (TBDs) such as Lyme disease result in ≈500,000 diagnoses annually in the United States. Various methods can reduce the abundance of ticks at small spatial scales, but whether these methods lower incidence of TBDs is poorly understood. We conducted a randomized, replicated, fully crossed, placebo-controlled, masked experiment to test whether 2 environmentally safe interventions, the Tick Control System (TCS) and Met52 fungal spray, used separately or together, affected risk for and incidence of TBDs in humans and pets in 24 residential neighborhoods. All participating properties in a neighborhood received the same treatment. TCS was associated with fewer questing ticks and fewer ticks feeding on rodents. The interventions did not result in a significant difference in incidence of human TBDs but did significantly reduce incidence in pets. Our study is consistent with previous evidence suggesting that reducing tick abundance in residential areas might not reduce incidence of TBDs in humans.

Powassan virus is a tickborne flavivirus that can cause lethal or debilitating neurologic illness. It is canonically transmitted by Ixodes spp. ticks but might spill over to sympatric Dermacentor species. We detected Powassan virus lineage I from a pool of field-collected D. variabilis ticks in New York, USA.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is spreading rapidly in Asia. This virus is transmitted by the Asian longhorned tick (Haemaphysalis longicornis), which has parthenogenetically and sexually reproducing populations. Parthenogenetic populations were found in ≥15 provinces in China and strongly correlated with the distribution of severe fever with thrombocytopenia syndrome cases. However, distribution of these cases was poorly correlated with the distribution of populations of bisexual ticks. Phylogeographic analysis suggested that the parthenogenetic population spread much faster than bisexual population because colonization is independent of sexual reproduction. A higher proportion of parthenogenetic ticks was collected from migratory birds captured at an SFTSV-endemic area, implicating the contribution to the long-range movement of these ticks in China. The SFTSV susceptibility of parthenogenetic females was similar to that of bisexual females under laboratory conditions. These results suggest that parthenogenetic Asian longhorned ticks, probably transported by migratory birds, play a major role in the rapid spread of SFTSV.

Report of a human death and exposure of white-tailed deer to Heartland virus (HRTV) in Georgia, USA, prompted the sampling of questing ticks during 2018-2019 in 26 sites near where seropositive deer were captured and the residence of the human case-patient. We processed 9,294 Amblyomma americanum ticks in pools by virus isolation in Vero E6 cells and reverse transcription PCR. Positive pools underwent whole-genome sequencing. Three pools were positive for HRTV (minimum infection rate 0.46/1,000 ticks) and none for Bourbon virus. Cell cultures confirmed HRTV presence in 2 pools. Genome sequencing, achieved for the 3 HRTV isolates, showed high similarity among samples but marked differences with previously sequenced HRTV isolates. The isolation and genomic characterization of HRTV from A. americanum ticks in Georgia confirm virus presence in the state. Clinicians and public health professionals should be aware of this emerging tickborne pathogen.

Tickborne diseases (TBDs) such as Lyme disease result in ≈500,000 diagnoses annually in the United States. Various methods can reduce the abundance of ticks at small spatial scales, but whether these methods lower incidence of TBDs is poorly understood. We conducted a randomized, replicated, fully crossed, placebo-controlled, masked experiment to test whether 2 environmentally safe interventions, the Tick Control System (TCS) and Met52 fungal spray, used separately or together, affected risk for and incidence of TBDs in humans and pets in 24 residential neighborhoods. All participating properties in a neighborhood received the same treatment. TCS was associated with fewer questing ticks and fewer ticks feeding on rodents. The interventions did not result in a significant difference in incidence of human TBDs but did significantly reduce incidence in pets. Our study is consistent with previous evidence suggesting that reducing tick abundance in residential areas might not reduce incidence of TBDs in humans.

Ticks are obligate hematophagous arthropods that are the second most prevalent vectors of human zoonotic pathogens after mosquitoes (1). Ticks harbor a vast number of pathogenic bacteria, viruses, and protozoa [...]

We demonstrated experimental acquisition and transmission of Heartland bandavirus by Haemaphysalis longicornis ticks. Virus was detected in tick salivary gland and midgut tissues. A total of 80% of mice exposed to 1 infected tick seroconverted, suggesting horizontal transmission. H. longicornis ticks can transmit the virus in the transovarial mode.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is spreading rapidly in Asia. This virus is transmitted by the Asian longhorned tick (Haemaphysalis longicornis), which has parthenogenetically and sexually reproducing populations. Parthenogenetic populations were found in ≥15 provinces in China and strongly correlated with the distribution of severe fever with thrombocytopenia syndrome cases. However, distribution of these cases was poorly correlated with the distribution of populations of bisexual ticks. Phylogeographic analysis suggested that the parthenogenetic population spread much faster than bisexual population because colonization is independent of sexual reproduction. A higher proportion of parthenogenetic ticks was collected from migratory birds captured at an SFTSV-endemic area, implicating the contribution to the long-range movement of these ticks in China. The SFTSV susceptibility of parthenogenetic females was similar to that of bisexual females under laboratory conditions. These results suggest that parthenogenetic Asian longhorned ticks, probably transported by migratory birds, play a major role in the rapid spread of SFTSV.

In Corsica, France, 9.1% of livestock serum samples collected during 2014–2016 were found to have antibodies against Crimean–Congo hemorrhagic fever virus (CCHFV), an emerging tickborne zoonotic disease. We tested 8,051 ticks for CCHFV RNA and Nairovirus RNA. The results indicate that Corsica is not a hotspot for CCHFV.

We previously detected a potentially novel reassortant of Crimean-Congo hemorrhagic fever virus in camels at the largest livestock market in the United Arab Emirates. A broader survey of large mammals at the site indicated zoonotic transmission is associated with dromedaries and camel ticks. Seroprevalence in cattle, sheep, and goats is minimal.

Borrelia bavariensis is one of several genospecies within the B. burgdorferi sensu lato complex to be associated with Lyme disease (1). B. bavariensis is widely distributed across Europe and Asia [...]

We demonstrated experimental acquisition and transmission of Heartland bandavirus by Haemaphysalis longicornis ticks. Virus was detected in tick salivary gland and midgut tissues. A total of 80% of mice exposed to 1 infected tick seroconverted, suggesting horizontal transmission. H. longicornis ticks can transmit the virus in the transovarial mode.

We document a case of Rickettsia parkeri rickettsiosis in a patient in Connecticut, USA, who became ill after a bite from a Gulf Coast tick (Amblyomma maculatum). We used PCR to amplify R. parkeri DNA from the detached tick. The patient showed a 4-fold rise in IgG reactive with R. parkeri antigens.

Crimean-Congo hemorrhagic fever (CCHF) is a tickborne zoonotic disease causing severe illness, considered by the World Health Organization to be 1 of the 7 highest-priority epidemic-prone diseases. CCHF is considered [...]

Tickborne orthonairoviruses have been considered a major public health threat worldwide (1). In China, other than Crimean-Congo hemorrhagic fever virus, there are 3 emerging orthonairoviruses: Tacheng tick virus 1 (2), [...]

We report molecular detection of Rickettsia africae in Amblyomma ovale ticks from Nicaragua and a novel rickettsial strain in an A. triste tick. Of 146 ticks from dogs, 16.4% were Rickettsia PCR positive. The presence of Rickettsia spp. in human-biting ticks in Nicaragua may pose a public health concern.

We collected 1,671 Dermacentor reticulatus ticks from 17 locations in the Czech Republic, Slovakia, and Hungary. We found 47.9% overall prevalence of Rickettsia species in ticks over all locations. Sequence analysis confirmed that all tested samples belonged to R. raoultii, the causative agent of tick-borne lymphadenopathy.

We collected questing Haemaphysalis longicornis ticks from southeastern counties of Pennsylvania, USA. Of 263 ticks tested by PCR for pathogens, 1 adult female was positive for Borrelia burgdorferi sensu stricto, yielding a 0.4% infection rate. Continued monitoring of this invasive tick is essential to determine its public health role.

Anaplasma phagocytophilum is the bacterium capable of causing anaplasmosis (2,2). Anaplasmosis symptoms include fever, headache, myalgia, and malaise (3). Severe illness is reported more commonly in older and immunocompromised patients [...]

Migratory birds can transport infected ticks across continents. We evaluated pathogens in ticks collected from migratory birds in Italy. We found DNA from Rickettsia aeschlimannii, R. africae, and R. raoultii bacteria, all of which can cause disease in humans. Bird migrations might facilitate the spread of these pathogens into new areas.

During 2013–2019, Borrelia miyamotoi infection was detected in 19 US states. Infection rate was 0.5%–3.2%; of B. miyamotoi–positive ticks, 59.09% had concurrent infections. B. miyamotoi is homogeneous with 1 genotype from Ixodes scapularis ticks in northeastern and midwestern states and 1 from I. pacificus in western states.

Anaplasmosis, caused by the tickborne bacterium Anaplasma phagocytophilum, is an emerging public health threat in the United States. In the northeastern United States, the blacklegged tick (Ixodes scapularis) transmits the human pathogenic genetic variant of A. phagocytophilum (Ap-ha) and a nonpathogenic variant (Ap-V1). New York has recently experienced a rapid and geographically focused increase in cases of anaplasmosis. We analyzed A. phagocytophilum–infected I. scapularis ticks collected across New York during 2008–2020 to differentiate between variants and calculate an entomological risk index (ERI) for each. Ap-ha ERI varied between regions and increased in all regions during the final years of the study. Space-time scan analyses detected expanding clusters of Ap-ha located within documented anaplasmosis hotspots. Ap-ha ERI was more positively correlated with anaplasmosis incidence than non-genotyped A. phagocytophilum ERI. Our findings help elucidate the relationship between the spatial ecology of A. phagocytophilum variants and anaplasmosis.

We studied the prevalence of tickborne pathogens in canine ticks, South Korea, during 2010-2015. Results revealed a high prevalence of the emerging pathogen Rickettsia raoultii. Dog ticks may be maintenance hosts for tickborne pathogens, suggesting the need to continually evaluate the potential public health threat posed by R. raoultii-infected ticks.

Human cases of Crimean-Congo hemorrhagic fever (CCHF) were first detected in Spain in 2016. National human and animal health authorities organized a large, multidisciplinary study focusing on ticks as sentinels to determine the nationwide distribution of ticks with CCHF virus. Ticks were collected from animals and vegetation, samples pooled (12,584 ticks; 4,556 pools), and molecular methods used to look for the virus. We detected the virus in 135 pools from most of the regions studied, indicating that it is widespread in Spain. We found sequences of CCHF virus genotypes I, III, and IV in the tick species collected, most commonly in Hyalomma lusitanicum, suggesting this tick has a prominent role in the virus's natural cycle. The red deer (Cervus elaphus) was the host that most frequently yielded positive ticks. Our study highlights the need for larger studies in Spain to ascertain the complete risk to public health.

Kasokero virus (KASV; genus Orthonairovirus) was first isolated in 1977 at Uganda Virus Research Institute from serum collected from Rousettus aegyptiacus bats captured at Kasokero Cave, Uganda. During virus characterization studies at the institute, 4 laboratory-associated infections resulted in mild to severe disease. Although orthonairoviruses are typically associated with vertebrate and tick hosts, a tick vector of KASV never has been reported. We tested 786 Ornithodoros (Reticulinasus) faini tick pools (3,930 ticks) for KASV. The ticks were collected from a large R. aegyptiacus bat roosting site in western Uganda. We detected KASV RNA in 43 tick pools and recovered 2 infectious isolates, 1 of which was derived from host blood–depleted ticks. Our findings suggest that KASV is maintained in an enzootic transmission cycle involving O. (R.) faini ticks and R. aegyptiacus bats and has the potential for incidental virus spillover to humans.

Ticks and tickborne diseases are increasingly problematic. There have been positive developments that should result in improved strategies and better tools to suppress ticks, reduce human tick bites, and roll back tickborne diseases. However, we equally need to address the question of who is responsible for implementing the solutions. The current model of individual responsibility for tick control evolved from a scenario in the 1990s focusing strongly on exposure to blacklegged ticks and Lyme disease spirochetes in peridomestic settings of the northeastern United States. Today, the threat posed by human-biting ticks is more widespread across the eastern United States, increasingly complex (multiple tick species and >10 notable tickborne pathogens), and, across tick species, more spatially diffuse (including backyards, neighborhood green spaces, and public recreation areas). To mitigate tick-associated negative societal effects, we must consider shifting the responsibility for tick control to include both individual persons and professionally staffed tick-management programs.

During 2016-2018, we collected 3,193 ticks from rural areas in South Korea to investigate the prevalence of severe fever with thrombocytopenia syndrome virus (SFTSV). We detected SFTSV in ticks at an infection rate (IR) of 11.1%. We noted increases in the human IR associated with the monthly SFTSV IR in ticks.

In 2018, Heartland disease virus infected 2 persons in Illinois, USA. In 2019, ticks were collected at potential tick bite exposure locations and tested for Heartland and Bourbon viruses. A Heartland virus-positive pool of adult male Amblyomma americanum ticks was found at 2 locations, 439 km apart, suggesting widespread distribution in Illinois.

Report of a human death and exposure of white-tailed deer to Heartland virus (HRTV) in Georgia, USA, prompted the sampling of questing ticks during 2018–2019 in 26 sites near where seropositive deer were captured and the residence of the human case-patient. We processed 9,294 Amblyomma americanum ticks in pools by virus isolation in Vero E6 cells and reverse transcription PCR. Positive pools underwent whole-genome sequencing. Three pools were positive for HRTV (minimum infection rate 0.46/1,000 ticks) and none for Bourbon virus. Cell cultures confirmed HRTV presence in 2 pools. Genome sequencing, achieved for the 3 HRTV isolates, showed high similarity among samples but marked differences with previously sequenced HRTV isolates. The isolation and genomic characterization of HRTV from A. americanum ticks in Georgia confirm virus presence in the state. Clinicians and public health professionals should be aware of this emerging tickborne pathogen.

Powassan virus is a tickborne flavivirus that can cause lethal or debilitating neurologic illness. It is canonically transmitted by Ixodes spp. ticks but might spill over to sympatric Dermacentor species. We detected Powassan virus lineage I from a pool of field-collected D. variabilis ticks in New York, USA. [ABSTRACT FROM AUTHOR]

We conducted a molecular survey for Borrelia spp. in Ornithodoros ticks previously reported as biting humans. We collected specimens in natural ecosystems and inside human dwellings in 6 states in Brazil. Phylogenetic analyses unveiled the occurrence of 4 putatively new species of relapsing fever group borreliae.

Worldwide, only mosquitoes spread more vectorborne diseases than ticks; however, in temperate areas of North America, Europe, and Asia, ticks cause most vectorborne diseases. Ticks are vectors for multiple viruses, [...]

Migratory birds can transport infected ticks across continents. We evaluated pathogens in ticks collected from migratory birds in Italy. We found DNA from Rickettsia aeschlimannii, R. africae, and R. raoultii bacteria, all of which can cause disease in humans. Bird migrations might facilitate the spread of these pathogens into new areas.

We studied the prevalence of tickborne pathogens in canine ticks, South Korea, during 2010–2015. Results revealed a high prevalence of the emerging pathogen Rickettsia raoultii. Dog ticks may be maintenance hosts for tickborne pathogens, suggesting the need to continually evaluate the potential public health threat posed by R. raoultii–infected ticks.

Human cases of Crimean-Congo hemorrhagic fever (CCHF) were first detected in Spain in 2016. National human and animal health authorities organized a large, multidisciplinary study focusing on ticks as sentinels to determine the nationwide distribution of ticks with CCHF virus. Ticks were collected from animals and vegetation, samples pooled (12,584 ticks; 4,556 pools), and molecular methods used to look for the virus. We detected the virus in 135 pools from most of the regions studied, indicating that it is widespread in Spain. We found sequences of CCHF virus genotypes I, III, and IV in the tick species collected, most commonly in Hyalomma lusitanicum, suggesting this tick has a prominent role in the virus’s natural cycle. The red deer (Cervus elaphus) was the host that most frequently yielded positive ticks. Our study highlights the need for larger studies in Spain to ascertain the complete risk to public health.