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Sharma R, Patil RD, Singh B, Chakraborty S, Chandran D, Dhama K, Gopinath D, Jairath G, Rialch A, Mal G, Singh P, Chaicumpa W, Saikumar G. Tularemia - a re-emerging disease with growing concern. Vet Q 2023; 43:1-16. [PMID: 37916743 PMCID: PMC10732219 DOI: 10.1080/01652176.2023.2277753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/25/2023] [Indexed: 11/03/2023] Open
Abstract
Tularemia caused by Gram-negative, coccobacillus bacterium, Francisella tularensis, is a highly infectious zoonotic disease. Human cases have been reported mainly from the United States, Nordic countries like Sweden and Finland, and some European and Asian countries. Naturally, the disease occurs in several vertebrates, particularly lagomorphs. Type A (subspecies tularensis) is more virulent and causes disease mainly in North America; type B (subspecies holarctica) is widespread, while subspecies mediasiatica is present in central Asia. F. tularensis is a possible bioweapon due to its lethality, low infectious dosage, and aerosol transmission. Small mammals like rabbits, hares, and muskrats are primary sources of human infections, but true reservoir of F. tularensis is unknown. Vector-borne tularemia primarily involves ticks and mosquitoes. The bacterial subspecies involved and mode of transmission determine the clinical picture. Early signs are flu-like illnesses that may evolve into different clinical forms of tularemia that may or may not include lymphadenopathy. Ulcero-glandular and glandular forms are acquired by arthropod bite or handling of infected animals, oculo-glandular form as a result of conjunctival infection, and oro-pharyngeal form by intake of contaminated food or water. Pulmonary form appears after inhalation of bacteria. Typhoidal form may occur after infection via different routes. Human-to-human transmission has not been known. Diagnosis can be achieved by serology, bacterial culture, and molecular methods. Treatment for tularemia typically entails use of quinolones, tetracyclines, or aminoglycosides. Preventive measures are necessary to avoid infection although difficult to implement. Research is underway for the development of effective live attenuated and subunit vaccines.
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Affiliation(s)
- Rinku Sharma
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Rajendra Damu Patil
- Department of Veterinary Pathology, DGCN College of Veterinary and Animal Sciences, CSK HPKV, Palampur, Himachal Pradesh, India
| | - Birbal Singh
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Sandip Chakraborty
- Department of Veterinary Microbiology, College of Veterinary Sciences and Animal Husbandry, R.K. Nagar, West Tripura, India
| | | | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India
| | - Devi Gopinath
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Gauri Jairath
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Ajayta Rialch
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Gorakh Mal
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Putan Singh
- Disease Investigation Laboratory, ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, Himachal Pradesh, India
| | - Wanpen Chaicumpa
- Center of Research Excellence in Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - G. Saikumar
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India
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Ferreira FC, González J, Milholland MT, Tung GA, Fonseca DM. Ticks (Acari: Ixodida) on synanthropic small and medium-sized mammals in areas of the northeastern United States infested with the Asian longhorned tick, Haemaphysalis longicornis. Int J Parasitol 2023; 53:809-819. [PMID: 37467875 DOI: 10.1016/j.ijpara.2023.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 05/30/2023] [Accepted: 06/06/2023] [Indexed: 07/21/2023]
Abstract
The northeastern United States (US) is a hotspot for tick-borne diseases. Adding to an already complex vector landscape, in 2017 large populations of the invasive Haemaphysalis longicornis, the Asian longhorned tick, were detected in New Jersey (NJ) and later found to be widespread from Connecticut to Georgia. In its native range in northeastern Asia, H. longicornis is considered an important vector of deadly pathogens to humans, companion animals, and livestock. To identify the primary hosts of H. longicornis, we surveyed synanthropic small and medium-sized mammals in three different sites in suburban New Brunswick, NJ. Specifically, we collected approximately 9,000 tick specimens belonging to nine species from 11 different species of mammals sampled between May and September 2021. We found that H. longicornis feeds more frequently on rodents than previously thought, and that this invasive tick is likely exposed to important enzootic and zoonotic pathogens. Overall, we obtained detailed information about the seasonal dynamics and feeding patterns of six tick species common in the northeastern US, Haemaphysalis longicornis, Amblyomma americanum, Dermacentor variabilis, Ixodes scapularis, Ixodes texanus and Ixodes cookei. We found that unlike I. scapularis that feeds on mammals of all sizes, H. longicornis feeds on hosts following the general pattern of A. americanum, favoring larger species such as skunks, groundhogs, and raccoons. However, our survey revealed that unlike A. americanum, H. longicornis reaches high densities on Virginia opossum. Overall, the newly invasive H. longicornis was the most numerous tick species, both on multiple host species and in the environment, raising significant questions regarding its role in the epidemiology of tick-borne pathogens, especially those affecting livestock, companion animals and wildlife. In conclusion, our findings provide valuable insights into the tick species composition on mammalian hosts in NJ and the ongoing national expansion of H. longicornis.
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Affiliation(s)
- Francisco C Ferreira
- Center for Vector Biology, Entomology Department, Rutgers University, New Brunswick, NJ, USA.
| | - Julia González
- Center for Vector Biology, Entomology Department, Rutgers University, New Brunswick, NJ, USA. https://twitter.com/JulsGGlez
| | - Matthew T Milholland
- AGNR-Environmental Science and Technology, University of Maryland, College Park, MD, USA
| | - Grayson A Tung
- Center for Vector Biology, Entomology Department, Rutgers University, New Brunswick, NJ, USA
| | - Dina M Fonseca
- Center for Vector Biology, Entomology Department, Rutgers University, New Brunswick, NJ, USA.
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Sanchez-Vicente S, Tokarz R. Tick-Borne Co-Infections: Challenges in Molecular and Serologic Diagnoses. Pathogens 2023; 12:1371. [PMID: 38003835 PMCID: PMC10674443 DOI: 10.3390/pathogens12111371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/14/2023] [Accepted: 11/18/2023] [Indexed: 11/26/2023] Open
Abstract
Co-infections are a poorly understood aspect of tick-borne diseases. In the United States alone, nineteen different tick-borne pathogens have been identified. The majority of these agents are transmitted by only two tick species, Ixodes scapularis and Amblyomma americanum. Surveillance studies have demonstrated the presence of multiple pathogens in individual ticks suggesting a risk of polymicrobial transmission to humans. However, relatively few studies have explored this relationship and its impact on human disease. One of the key factors for this deficiency are the intrinsic limitations associated with molecular and serologic assays employed for the diagnosis of tick-borne diseases. Limitations in the sensitivity, specificity and most importantly, the capacity for inclusion of multiple agents within a single assay represent the primary challenges for the accurate detection of polymicrobial tick-borne infections. This review will focus on outlining these limitations and discuss potential solutions for the enhanced diagnosis of tick-borne co-infections.
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Affiliation(s)
- Santiago Sanchez-Vicente
- Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY 10032, USA;
| | - Rafal Tokarz
- Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY 10032, USA;
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
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Freeman EA, Salkeld DJ. Surveillance of Rocky Mountain wood ticks (Dermacentor andersoni) and American dog ticks (Dermacentor variabilis) in Colorado. Ticks Tick Borne Dis 2022; 13:102036. [PMID: 36274450 DOI: 10.1016/j.ttbdis.2022.102036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 04/05/2022] [Accepted: 08/25/2022] [Indexed: 11/18/2022]
Abstract
Ticks pose an emerging threat of infectious pathogen transmission in the United States in part due to expanding suitable habitat ranges in the wake of climate change. Active and passive tick surveillance can inform maps of tick distributions to warn the public of their risk of exposure to ticks. In Colorado, widespread active surveillance programs have difficulty due to the state's diverse terrain. However, combining multiple citizen science techniques can create a more accurate representation of tick distribution than any passive surveillance dataset alone. Our study uses county-level tick distribution data from Northern Arizona University, the Colorado Department of Public Health and the Environment, and veterinary surveillance in addition to literature data to assess the distribution of the Rocky Mountain wood tick, Dermacentor andersoni, and the American dog tick, Dermacentor variabilis. We found that D. andersoni for the most part inhabits counties at higher elevations than D. variabilis in Colorado.
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Affiliation(s)
- Elizabeth A Freeman
- Colorado School of Public Health, Colorado State University, Fort Collins, CO 80523, United States.
| | - Daniel J Salkeld
- Department of Biology, Colorado State University, Fort Collins, CO 80523, United States
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Koloski CW, Cassone BJ. Transcriptional profiling of Dermacentor variabilis (Acari: Ixodidae) provides insights into the role of the Haller's organ in spatial DEET recognition. Ticks Tick Borne Dis 2021; 13:101827. [PMID: 34610525 DOI: 10.1016/j.ttbdis.2021.101827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/30/2022]
Abstract
DEET is the most common active ingredient in commercial repellents, providing effective protection against blood-sucking insects and ticks. However, its mode of action is not fully understood, with several theories put forward to explain its repellency effect. Unique to ticks, the Haller's organ recognizes a variety of external stimuli through non-contact mechanisms, yet the extent to which the organ plays a role in tick chemoreception is not fully known. We previously found that DEET inhibited the expression/activity of cytochrome P450s and cholinesterases in Dermacentor variabilis, however, our experimental design could not distinguish between sexes (males/females), method of exposure (volatile/tactile) or the roles of chemosensory tissues (Haller's organ). In this study, we used RNA sequencing to assess changes in transcript expression induced by volatile DEET in D. variabilis males/females with/without intact Haller's organs. Male ticks showed much greater transcriptional responses to DEET than females, which may be at least partially attributed to the sexual dimorphism of the Haller's organ. Female transcript expression profiles were most influenced by condition (i.e., intact/excised Haller's organs) with minimal changes due to repellent exposure. On the other hand, removal of the Haller's organs caused DEET treated male ticks to exhibit similar expression profiles as control (ethanol) ticks with intact Haller's organs. Consequently, the transcript-level responses to spatial DEET exposure appears largely based on males possessing their Haller's organs. The molecular signature of this response included the suppression of a large number of transcripts involved in detoxification, lipid metabolism and immunity. Taken collectively, this study furthers our understanding of the Haller's organ role in volatile DEET recognition.
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Affiliation(s)
- Cody W Koloski
- Department of Biology, Brandon University, Brandon, MB R78 6A9, Canada
| | - Bryan J Cassone
- Department of Biology, Brandon University, Brandon, MB R78 6A9, Canada.
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Eisen RJ, Paddock CD. Tick and Tickborne Pathogen Surveillance as a Public Health Tool in the United States. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1490-1502. [PMID: 32440679 PMCID: PMC8905548 DOI: 10.1093/jme/tjaa087] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Indexed: 05/03/2023]
Abstract
In recent decades, tickborne disease (TBD) cases and established populations of medically important ticks have been reported over expanding geographic areas, and an increasing number of tickborne bacteria, viruses, and protozoans have been recognized as human pathogens, collectively contributing to an increasing burden of TBDs in the United States. The prevention and diagnosis of TBDs depend greatly on an accurate understanding by the public and healthcare providers of when and where persons are at risk for exposure to human-biting ticks and to the pathogens these ticks transmit. However, national maps showing the distributions of medically important ticks and the presence or prevalence of tickborne pathogens are often incomplete, outdated, or lacking entirely. Similar deficiencies exist regarding geographic variability in host-seeking tick abundance. Efforts to accurately depict acarological risk are hampered by lack of systematic and routine surveillance for medically important ticks and their associated human pathogens. In this review, we: 1) outline the public health importance of tick surveillance; 2) identify gaps in knowledge regarding the distributions and abundance of medically important ticks in the United States and the presence and prevalence of their associated pathogens; 3) describe key objectives for tick surveillance and review methods appropriate for addressing those goals; and 4) assess current capacity and barriers to implementation and sustainability of tick surveillance programs.
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Affiliation(s)
- Rebecca J. Eisen
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO
| | - Christopher D. Paddock
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA
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Hutcheson HJ, Mertins JW, Kondratieff BC, White MM. Ticks and Tick-Borne Diseases of Colorado, Including New State Records for Argas radiatus (Ixodida: Argasidae) and Ixodes brunneus (Ixodida: Ixodidae). JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:505-517. [PMID: 33164093 DOI: 10.1093/jme/tjaa232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Indexed: 06/11/2023]
Abstract
We report 28 species of ticks (Acari: Ixodida) from Colorado (CO). We include the soft ticks (Argasidae) Argas (Argas) cooleyi Kohls and Hoogstraal, Argas (Persicargas) radiatus Railliet, Carios (Alectorobius) concanensis (Cooley and Kohls), Carios (Alectorobius) kelleyi (Cooley and Kohls), Ornithodoros (Pavlovskyella) hermsi Wheeler et al., Ornithodoros (Pavlovskyella) parkeri Cooley, Ornithodoros (Pavlovskyella) turicata (Dugès), Otobius (Otobius) lagophilus Cooley and Kohls, and Otobius (Otobius) megnini (Dugès). We include the metastriate hard ticks (Ixodidae) Dermacentor (Americentor) albipictus (Packard), Dermacentor (Dermacentor) andersoni Stiles, Dermacentor (Dermacentor) parumapertus Neumann, Dermacentor (Dermacentor) variabilis (Say), Haemaphysalis (Aboimisalis) chordeilis (Packard), Haemaphysalis (Gonixodes) leporispalustris (Packard), and Rhipicephalus (Rhipicephalus) sanguineus Latreille. Prostriate hard ticks include Ixodes (Ixodiopsis) angustus Neumann, Ixodes (Phoeloioxdes) baergi Cooley and Kohls, Ixodes (Trichotoixodes) brunneus Koch, Ixodes (Scaphixodes) howelli Cooley and Kohls, Ixodes (Phoeloioxdes) kingi Bishopp, Ixodes (Phoeloioxdes) marmotae Cooley and Kohls, Ixodes (Ixodiopsis) ochotonae Gregson, Ixodes (Phoeloioxdes) sculptus Neumann, Ixodes (Ixodiopsis) soricis Gregson, Ixodes (Ixodes) spinipalpis Hadwen and Nuttall, Ixodes (Phoeloioxdes) texanus Banks, and Ixodes (Ixodiopsis) woodi Bishopp. Argas radiatus and Ixodes brunneus represent new state records. Review of collection reports revealed that inclusion of Ixodes (Multidentatus) auritulus (Neumann), Ixodes (Phoeloioxdes) cookei Packard, Ixodes (Phoeloioxdes) marxi Banks, and Ixodes (Ixodes) pacificus Cooley and Kohls is dubious or unconfirmed and, conversely, that C. concanensis and H. chordeilis have distributions that include CO. We list an additional five species occasionally detected and 13 exotic species intercepted in CO. Tick-host associations, geographical distributions, and medical/veterinary importance are included.
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Affiliation(s)
- H Joel Hutcheson
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, Diagnostics and Biologics, National Veterinary Services Laboratories, Ames, IA
| | - James W Mertins
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, Diagnostics and Biologics, National Veterinary Services Laboratories, Ames, IA
| | - Boris C Kondratieff
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO
| | - Monica M White
- Colorado Tick-Borne Disease Awareness Association, Poncha Springs, CO
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Lynn GE, Diktas H, DePonte K, Fikrig E. Naturally Acquired Resistance to Ixodes scapularis Elicits Partial Immunity against Other Tick Vectors in a Laboratory Host. Am J Trop Med Hyg 2021; 104:175-183. [PMID: 33258439 PMCID: PMC7790098 DOI: 10.4269/ajtmh.20-0776] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/04/2020] [Indexed: 12/15/2022] Open
Abstract
In many regions where ticks negatively impact public health or economic production, multiple medically important tick species may have overlapping geographic distribution, and in North America, this includes members of Ixodes, Dermacentor, and Amblyomma genera. Acquired tick resistance is the process by which some animals develop an immune response against feeding ticks after one or more exposures. This form of immunity can restrict the ability of ticks to feed and may inhibit transmission of pathogens. Likewise, many proteins present in tick saliva are conserved among tick species, and prior studies have reported cross-protective host immunity against certain combinations of ticks. In this study, we used a guinea pig model to assess whether host resistance against Ixodes scapularis could confer protection against two other medically important tick vectors, Dermacentor variabilis and Amblyomma americanum. Tick challenges using nymphs were used to induce host resistance against a primary species, followed by additional challenge using a secondary tick species. Tick attachment to hosts and engorgement weights were reduced significantly for D. variabilis and A. americanum feeding on I. scapularis-sensitized hosts. Reciprocally, I. scapularis engorgement weights were reduced to a lesser extent, and attachment was unaffected when feeding on hosts sensitized with either D. variabilis or A. americanum. These results indicate that immunity against I. scapularis could potentially be exploited for use in an anti-tick vaccine targeting multiple tick species and their associated pathogens.
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Affiliation(s)
- Geoffrey E. Lynn
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, Connecticut
| | - Husrev Diktas
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, Connecticut
| | - Kathleen DePonte
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, Connecticut
| | - Erol Fikrig
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, Connecticut
- Howard Hughes Medical Institute, Chevy Chase, Maryland
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Tully BG, Huntley JF. A Francisella tularensis Chitinase Contributes to Bacterial Persistence and Replication in Two Major U.S. Tick Vectors. Pathogens 2020; 9:pathogens9121037. [PMID: 33321814 PMCID: PMC7764610 DOI: 10.3390/pathogens9121037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 02/07/2023] Open
Abstract
Nearly 100 years after the first report of tick-borne tularemia, questions remain about the tick vector(s) that pose the greatest risk for transmitting Francisella tularensis (Ft), the causative agent of tularemia. Additionally, few studies have identified genes/proteins required for Ft to infect, persist, and replicate in ticks. To answer questions about vector competence and Ft transmission by ticks, we infected Dermacentor variabilis (Dv),Amblyomma americanum (Aa), and Haemaphysalis longicornis (Hl; invasive species from Asia) ticks with Ft, finding that although Aa ticks initially become infected with 1 order of magnitude higher Ft, Ft replicated more robustly in Dv ticks, and did not persist in Hl ticks. In transmission studies, both Dv and Aa ticks efficiently transmitted Ft to naïve mice, causing disease in 57% and 46% of mice, respectively. Of four putative Ft chitinases, FTL1793 is the most conserved among Francisella sp. We generated a ΔFTL1793 mutant and found that ΔFTL1793 was deficient for infection, persistence, and replication in ticks. Recombinant FTL1793 exhibited chitinase activity in vitro, suggesting that FTL1793 may provide an alternative energy source for Ft in ticks. Taken together, Dv ticks appear to pose a greater risk for harboring and transmitting tularemia and FTL1793 plays a major role in promoting tick infections by Ft.
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Mechanisms Affecting the Acquisition, Persistence and Transmission of Francisella tularensis in Ticks. Microorganisms 2020; 8:microorganisms8111639. [PMID: 33114018 PMCID: PMC7690693 DOI: 10.3390/microorganisms8111639] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/15/2020] [Accepted: 10/21/2020] [Indexed: 01/06/2023] Open
Abstract
Over 600,000 vector-borne disease cases were reported in the United States (U.S.) in the past 13 years, of which more than three-quarters were tick-borne diseases. Although Lyme disease accounts for the majority of tick-borne disease cases in the U.S., tularemia cases have been increasing over the past decade, with >220 cases reported yearly. However, when comparing Borrelia burgdorferi (causative agent of Lyme disease) and Francisella tularensis (causative agent of tularemia), the low infectious dose (<10 bacteria), high morbidity and mortality rates, and potential transmission of tularemia by multiple tick vectors have raised national concerns about future tularemia outbreaks. Despite these concerns, little is known about how F. tularensis is acquired by, persists in, or is transmitted by ticks. Moreover, the role of one or more tick vectors in transmitting F. tularensis to humans remains a major question. Finally, virtually no studies have examined how F. tularensis adapts to life in the tick (vs. the mammalian host), how tick endosymbionts affect F. tularensis infections, or whether other factors (e.g., tick immunity) impact the ability of F. tularensis to infect ticks. This review will assess our current understanding of each of these issues and will offer a framework for future studies, which could help us better understand tularemia and other tick-borne diseases.
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Lehane A, Parise C, Evans C, Beati L, Nicholson WL, Eisen RJ. Reported County-Level Distribution of the American Dog Tick (Acari: Ixodidae) in the Contiguous United States. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:131-155. [PMID: 31368492 PMCID: PMC8911316 DOI: 10.1093/jme/tjz119] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Indexed: 05/03/2023]
Abstract
In the United States, tick-borne diseases are increasing in incidence and cases are reported over an expanding geographical area. Avoiding tick bites is a key strategy in tick-borne disease prevention, and this requires current and accurate information on where humans are at risk for exposure to ticks. Based on a review of published literature and records in the U.S. National Tick Collection and National Ecological Observatory Network databases, we compiled an updated county-level map showing the reported distribution of the American dog tick, Dermacentor variabilis (Say). We show that this vector of the bacterial agents causing Rocky Mountain spotted fever and tularemia is widely distributed, with records derived from 45 states across the contiguous United States. However, within these states, county-level records of established tick populations are limited. Relative to the range of suitable habitat for this tick, our data imply that D. variabilis is currently underreported in the peer-reviewed literature, highlighting a need for improved surveillance and documentation of existing tick records.
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Affiliation(s)
- Aine Lehane
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - Christina Parise
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - Colleen Evans
- U.S. National Tick Collection, Institute for Coastal Plain Science, Georgia Southern University, 202 Georgia Avenue, Statesboro, GA 30460
| | - Lorenza Beati
- U.S. National Tick Collection, Institute for Coastal Plain Science, Georgia Southern University, 202 Georgia Avenue, Statesboro, GA 30460
| | - William L. Nicholson
- Rickettsial Zoonoses Branch, 1600 Clifton Road, NE, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333
| | - Rebecca J. Eisen
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
- Corresponding author,
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Abstract
Tularemia is a Holarctic zoonosis caused by the gamma proteobacterium Francisella tularensis and is considered to be a vector-borne disease. In many regions, human risk is associated with the bites of flies, mosquitoes, or ticks. But the biology of the agent is such that risk may be fomite related, and large outbreaks can occur due to inhalation or ingestion of contaminated materials. Such well-documented human risk factors suggest a role for these risk factors in the enzootic cycle as well. Many arthropods support the growth or survival of the agent, but whether arthropods (ticks in particular) are obligately required for the perpetuation of F. tularensis remains to be demonstrated. As with most zoonoses, our knowledge of the ecology of F. tularensis has been driven with the objective of understanding human risk. In this review, we focus on the role of the arthropod in maintaining F. tularensis, particularly with respect to long-term enzootic persistence.
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Affiliation(s)
- Sam R Telford
- Department of Infectious Disease and Global Health and New England Regional Biosafety Laboratory, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536, USA;
| | - Heidi K Goethert
- Department of Infectious Disease and Global Health and New England Regional Biosafety Laboratory, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536, USA;
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Zellner B, Huntley JF. Ticks and Tularemia: Do We Know What We Don't Know? Front Cell Infect Microbiol 2019; 9:146. [PMID: 31139576 PMCID: PMC6517804 DOI: 10.3389/fcimb.2019.00146] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/23/2019] [Indexed: 01/01/2023] Open
Abstract
Francisella tularensis, the causative agent of the zoonotic disease tularemia, is characterized by high morbidity and mortality rates in over 190 different mammalian species, including humans. Based on its low infectious dose, multiple routes of infection, and ability to induce rapid and lethal disease, F. tularensis has been recognized as a severe public health threat—being designated as a NIH Category A Priority Pathogen and a CDC Tier 1 Select Agent. Despite concerns over its use as a bioweapon, most U.S. tularemia cases are tick-mediated and ticks are believed to be the major environmental reservoir for F. tularensis in the U.S. The American dog tick (Dermacentor variabilis) has been reported to be the primary tick vector for F. tularensis, but the lone star tick (Amblyomma americanum) and other tick species also have been shown to harbor F. tularensis. This review highlights what is known, not known, and is debated, about the roles of different tick species as environmental reservoirs and transmission vectors for a variety of F. tularensis genotypes/strains.
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Affiliation(s)
- Briana Zellner
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Jason F Huntley
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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Merrill MM, Boughton RK, Lord CC, Sayler KA, Wight B, Anderson WM, Wisely SM. Wild pigs as sentinels for hard ticks: A case study from south-central Florida. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2018; 7:161-170. [PMID: 29988828 PMCID: PMC6032497 DOI: 10.1016/j.ijppaw.2018.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/23/2018] [Accepted: 04/25/2018] [Indexed: 12/23/2022]
Abstract
As a result of shifts in the habitable range of ticks due to climate change and the ongoing threat of exotic tick species introductions, efficient surveillance tools for these pests and disease vectors are needed. Wild pigs are habitat generalists, distributed throughout most of the United States, and often hunted recreationally or removed as part of management programs, making them potentially useful sentinel hosts for ticks. We compared ticks collected from captured wild pigs and standard tick dragging methods on a south-central Florida cattle ranch from May 2015-August 2017. Three hundred and sixteen wild pigs were surveyed, and 84 km spanning three habitat types (seminative pasture, improved pasture, and hammock) were dragged. In total, 1023 adults of four species (Amblyomma auricularium, Amblyomma maculatum, Dermacentor variabilis, and Ixodes scapularis) were collected from wild pigs, while 39 adults of three species (A. auricularium, A. maculatum, and I. scapularis) were collected from drags. Only one immature specimen, a nymph, was collected from a pig, while dragging collected 2808 larvae and 150 nymphs. Amblyomma maculatum comprised 96% of adults collected from pigs, while A. maculatum, I. scapularis, and A. auricularium comprised 38%, 33%, and 28% of adults collected from drags, respectively. Adults of all tick species found on drags were found on pigs, and wild pig surveillance detected adults of an additional species not found on drags. Dragging was far superior for collection of immatures but not for adults of most species found in this study. These findings suggest wild pigs could be used as a sentinel for the detection of tick species. When combined with ongoing wild pig research, hunting, or management, wild pig surveillance can provide an effective method to survey for adult tick presence of some species of interest and may assist in tracking the range expansion of some tick species.
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Affiliation(s)
- Mary M Merrill
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, PO Box 100188, Gainesville, FL 32610, USA
| | - Raoul K Boughton
- Department of Wildlife Ecology and Conservation, Institute of Food and Agricultural Sciences, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL 32611, USA
| | - Cynthia C Lord
- Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, 200 9th St SE, Vero Beach, FL 32962, USA
| | - Katherine A Sayler
- Department of Wildlife Ecology and Conservation, Institute of Food and Agricultural Sciences, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL 32611, USA
| | - Bethany Wight
- Department of Wildlife Ecology and Conservation, Institute of Food and Agricultural Sciences, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL 32611, USA
| | - Wesley M Anderson
- Department of Wildlife Ecology and Conservation, Institute of Food and Agricultural Sciences, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL 32611, USA
| | - Samantha M Wisely
- Department of Wildlife Ecology and Conservation, Institute of Food and Agricultural Sciences, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL 32611, USA
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Eisen RJ, Kugeler KJ, Eisen L, Beard CB, Paddock CD. Tick-Borne Zoonoses in the United States: Persistent and Emerging Threats to Human Health. ILAR J 2017; 58:319-335. [PMID: 28369515 PMCID: PMC5610605 DOI: 10.1093/ilar/ilx005] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 02/01/2017] [Indexed: 01/02/2023] Open
Abstract
In the United States, ticks transmit the greatest diversity of arthropod-borne pathogens and are responsible for the most cases of all vector-borne diseases. In recent decades, the number of reported cases of notifiable tick-borne diseases has steadily increased, geographic distributions of many ticks and tick-borne diseases have expanded, and new tick-borne disease agents have been recognized. In this review, we (1) describe the known disease agents associated with the most commonly human-biting ixodid ticks, (2) review the natural histories of these ticks and their associated pathogens, (3) highlight spatial and temporal changes in vector tick distributions and tick-borne disease occurrence in recent decades, and (4) identify knowledge gaps and barriers to more effective prevention of tick-borne diseases. We describe 12 major tick-borne diseases caused by 15 distinct disease agents that are transmitted by the 8 most commonly human-biting ixodid ticks in the United States. Notably, 40% of these pathogens were described within the last two decades. Our assessment highlights the importance of animal studies to elucidate how tick-borne pathogens are maintained in nature, as well as advances in molecular detection of pathogens which has led to the discovery of several new tick-borne disease agents.
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Affiliation(s)
- Rebecca J Eisen
- Rebecca J. Eisen, PhD, is a Research Biologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Kiersten J. Kugeler, PhD, is an Epidemiologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Lars Eisen, PhD, is a Research Entomologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Charles B. Beard, PhD, is a Branch Chief in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Christopher D. Paddock, MD, is a Medical Officer/Pathologist in the Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Atlanta, Georgia
| | - Kiersten J Kugeler
- Rebecca J. Eisen, PhD, is a Research Biologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Kiersten J. Kugeler, PhD, is an Epidemiologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Lars Eisen, PhD, is a Research Entomologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Charles B. Beard, PhD, is a Branch Chief in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Christopher D. Paddock, MD, is a Medical Officer/Pathologist in the Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Atlanta, Georgia
| | - Lars Eisen
- Rebecca J. Eisen, PhD, is a Research Biologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Kiersten J. Kugeler, PhD, is an Epidemiologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Lars Eisen, PhD, is a Research Entomologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Charles B. Beard, PhD, is a Branch Chief in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Christopher D. Paddock, MD, is a Medical Officer/Pathologist in the Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Atlanta, Georgia
| | - Charles B Beard
- Rebecca J. Eisen, PhD, is a Research Biologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Kiersten J. Kugeler, PhD, is an Epidemiologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Lars Eisen, PhD, is a Research Entomologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Charles B. Beard, PhD, is a Branch Chief in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Christopher D. Paddock, MD, is a Medical Officer/Pathologist in the Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Atlanta, Georgia
| | - Christopher D Paddock
- Rebecca J. Eisen, PhD, is a Research Biologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Kiersten J. Kugeler, PhD, is an Epidemiologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Lars Eisen, PhD, is a Research Entomologist in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Charles B. Beard, PhD, is a Branch Chief in the Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Fort Collins, Colorado. Christopher D. Paddock, MD, is a Medical Officer/Pathologist in the Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention in Atlanta, Georgia
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Schorderet-Weber S, Noack S, Selzer PM, Kaminsky R. Blocking transmission of vector-borne diseases. Int J Parasitol Drugs Drug Resist 2017; 7:90-109. [PMID: 28189117 PMCID: PMC5302141 DOI: 10.1016/j.ijpddr.2017.01.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/22/2017] [Indexed: 12/16/2022]
Abstract
Vector-borne diseases are responsible for significant health problems in humans, as well as in companion and farm animals. Killing the vectors with ectoparasitic drugs before they have the opportunity to pass on their pathogens could be the ideal way to prevent vector borne diseases. Blocking of transmission might work when transmission is delayed during blood meal, as often happens in ticks. The recently described systemic isoxazolines have been shown to successfully prevent disease transmission under conditions of delayed pathogen transfer. However, if the pathogen is transmitted immediately at bite as it is the case with most insects, blocking transmission becomes only possible if ectoparasiticides prevent the vector from landing on or, at least, from biting the host. Chemical entities exhibiting repellent activity in addition to fast killing, like pyrethroids, could prevent pathogen transmission even in cases of immediate transfer. Successful blocking depends on effective action in the context of the extremely diverse life-cycles of vectors and vector-borne pathogens of medical and veterinary importance which are summarized in this review. This complexity leads to important parameters to consider for ectoparasiticide research and when considering the ideal drug profile for preventing disease transmission.
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Affiliation(s)
| | - Sandra Noack
- Boehringer Ingelheim Animal Health GmbH, Binger Str. 173, 55216 Ingelheim, Germany.
| | - Paul M Selzer
- Boehringer Ingelheim Animal Health GmbH, Binger Str. 173, 55216 Ingelheim, Germany.
| | - Ronald Kaminsky
- ParaC Consulting for Parasitology and Drug Discovery, Altenstein 13, 79685 Haeg-Ehrsberg, Germany.
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Brown VR, Adney DR, Olea-Popelka F, Bowen RA. Prior Inoculation with Type B Strains of Francisella tularensis Provides Partial Protection against Virulent Type A Strains in Cottontail Rabbits. PLoS One 2015; 10:e0140723. [PMID: 26474413 PMCID: PMC4608750 DOI: 10.1371/journal.pone.0140723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/28/2015] [Indexed: 11/18/2022] Open
Abstract
Francisella tularensis is a highly virulent bacterium that is capable of causing severe disease (tularemia) in a wide range of species. This organism is characterized into two distinct subspecies: tularensis (type A) and holarctica (type B) which vary in several crucial ways, with some type A strains having been found to be considerably more virulent in humans and laboratory animals. Cottontail rabbits have been widely implicated as a reservoir species for this subspecies; however, experimental inoculation in our laboratory revealed type A organisms to be highly virulent, resulting in 100% mortality following challenge with 50-100 organisms. Inoculation of cottontail rabbits with the same number of organisms from type B strains of bacteria was found to be rarely lethal and to result in a robust humoral immune response. The objective of this study was to characterize the protection afforded by a prior challenge with type B strains against a later inoculation with a type A strain in North American cottontail rabbits (Sylvilagus spp). Previous infection with a type B strain of organism was found to lengthen survival time and in some cases prevent death following inoculation with a type A2 strain of F. tularensis. In contrast, inoculation of a type A1b strain was uniformly lethal in cottontail rabbits irrespective of a prior type B inoculation. These findings provide important insight about the role cottontail rabbits may play in environmental maintenance and transmission of this organism.
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Affiliation(s)
- Vienna R. Brown
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, United States of America
| | - Danielle R. Adney
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, United States of America
| | - Francisco Olea-Popelka
- Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado, 80523, United States of America
| | - Richard A. Bowen
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, United States of America
- * E-mail:
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Genchi M, Prati P, Vicari N, Manfredini A, Sacchi L, Clementi E, Bandi C, Epis S, Fabbi M. Francisella tularensis: No Evidence for Transovarial Transmission in the Tularemia Tick Vectors Dermacentor reticulatus and Ixodes ricinus. PLoS One 2015; 10:e0133593. [PMID: 26244842 PMCID: PMC4526560 DOI: 10.1371/journal.pone.0133593] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/30/2015] [Indexed: 11/22/2022] Open
Abstract
Background Tularemia is a zoonosis caused by the Francisella tularensis, a highly infectious Gram-negative coccobacillus. Due to easy dissemination, multiple routes of infection, high environmental contamination and morbidity and mortality rates, Francisella is considered a potential bioterrorism threat and classified as a category A select agent by the CDC. Tick bites are among the most prevalent modes of transmission, and ticks have been indicated as a possible reservoir, although their reservoir competence has yet to be defined. Tick-borne transmission of F. tularensis was recognized in 1923, and transstadial transmission has been demonstrated in several tick species. Studies on transovarial transmission, however, have reported conflicting results. Objective The aim of this study was to evaluate the role of ticks as reservoirs for Francisella, assessing the transovarial transmission of F. tularensis subsp. holarctica in ticks, using experimentally-infected females of Dermacentor reticulatus and Ixodes ricinus. Results Transmission electron microscopy and fluorescence in situ hybridization showed F. tularensis within oocytes. However, cultures and bioassays of eggs and larvae were negative; in addition, microscopy techniques revealed bacterial degeneration/death in the oocytes. Conclusions These results suggest that bacterial death might occur in oocytes, preventing the transovarial transmission of Francisella. We can speculate that Francisella does not have a defined reservoir, but that rather various biological niches (e.g. ticks, rodents), that allow the bacterium to persist in the environment. Our results, suggesting that ticks are not competent for the bacterium vertical transmission, are congruent with this view.
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Affiliation(s)
- Marco Genchi
- National Reference Laboratory for Tularemia, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Pavia, Italy
- * E-mail:
| | - Paola Prati
- National Reference Laboratory for Tularemia, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Pavia, Italy
| | - Nadia Vicari
- National Reference Laboratory for Tularemia, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Pavia, Italy
| | - Andrea Manfredini
- National Reference Laboratory for Tularemia, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Pavia, Italy
| | - Luciano Sacchi
- Department of Biology and Biotechnology (Lazzaro Spallanzani), Università degli Studi di Pavia, Pavia, Italy
| | - Emanuela Clementi
- Department of Biology and Biotechnology (Lazzaro Spallanzani), Università degli Studi di Pavia, Pavia, Italy
| | - Claudio Bandi
- Department of Veterinary Science and Public Health (Divet), Università degli Studi di Milano, Milan, Italy
| | - Sara Epis
- Department of Veterinary Science and Public Health (Divet), Università degli Studi di Milano, Milan, Italy
| | - Massimo Fabbi
- National Reference Laboratory for Tularemia, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, Pavia, Italy
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PATHOGENESIS AND IMMUNE RESPONSES OF FRANCISELLA TULARENSIS STRAINS IN WILD-CAUGHT COTTONTAIL RABBITS (SYLVILAGUS SPP.). J Wildl Dis 2015; 51:564-75. [PMID: 25984770 DOI: 10.7589/2015-02-030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Francisella tularensis is a highly virulent, zoonotic bacterium that causes significant natural disease and is of concern as an organism for bioterrorism. Serologic testing of wildlife is frequently used to monitor spatial patterns of infection and to quantify exposure. Cottontail rabbits (Sylvilagus spp.) are a natural reservoir for F. tularensis in the US, although very little work has been done experimentally to determine how these animals respond to infection; thus, information gathered from field samples can be difficult to interpret. We characterized clinical disease, bacteremia, pathology, and antibody kinetics of North American cottontail rabbits experimentally infected with five strains of F. tularensis. Rabbits were infected with four field strains, including MA00-2987 (type A1b), WY96-3418 (type A2), KY99-3387, and OR96-0246 (type B), and with SchuS4 (type A1a), a widely used, virulent laboratory strain. Infection with the different strains of the bacterium resulted in varied patterns of clinical disease, gross pathology, and histopathology. Each of the type A strains were highly virulent, with rabbits succumbing to infection 3-13 d after infection. At necropsy, numerous microabscesses were observed in the livers and spleens of most rabbits, associated with high bacterial organ burdens. In contrast, most rabbits infected with type B strains developed mild fever and became lethargic, but the disease was infrequently lethal. Those rabbits infected with type B strains that survived past 14 d developed a robust humoral immune response, and F. tularensis was not isolated from liver, spleen, or lung of those animals. Understanding F. tularensis infection in a natural reservoir species can guide serosurveillance and generate new insights into environmental maintenance of this pathogen.
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Reproducible and quantitative model of infection of Dermacentor variabilis with the live vaccine strain of Francisella tularensis. Appl Environ Microbiol 2014; 81:386-95. [PMID: 25362054 DOI: 10.1128/aem.02917-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pathogen life cycles in mammalian hosts have been studied extensively, but studies with arthropod vectors represent considerable challenges. In part this is due to the difficulty of delivering a reproducible dose of bacteria to follow arthropod-associated replication. We have established reproducible techniques to introduce known numbers of Francisella tularensis strain LVS from mice into Dermacentor variabilis nymphs. Using this model infection system, we performed dose-response infection experiments and followed bacterial replication through the molt to adults and at later time points. During development to adults, bacteria replicate to high numbers and can be found associated with the gut tissues, salivary glands, and hemolymph of adult ticks. Further, we can transmit a mutant of LVS (LVS ΔpurMCD) that cannot replicate in macrophages in vitro or in mice to nymphs. Our data show that the LVS ΔpurMCD mutant cannot be transstadially transmitted from nymphs to adult ticks. We then show that a plasmid-complemented strain of this mutant is recoverable in adult ticks and necessary for bacterial replication during the molt. In a mixed-infection assay (ΔpurMCD mutant versus ΔpurMCD complement), 98% of the recovered bacteria retained the plasmid marker. These data suggest that the ΔpurMCD mutation cannot be rescued by the presence a complemented strain in a mixed infection. Importantly, our infection model provides a platform to test specific mutants for their replication in ticks, perform competition studies, and use other genetic techniques to identify F. tularensis genes that are expressed or required in this unique environment.
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Dergousoff SJ, Galloway TD, Lindsay LR, Curry PS, Chilton NB. Range expansion of Dermacentor variabilis and Dermacentor andersoni (Acari: Ixodidae) near their northern distributional limits. JOURNAL OF MEDICAL ENTOMOLOGY 2013; 50:510-520. [PMID: 23802445 DOI: 10.1603/me12193] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Distributional ranges of the ticks Dermacentor andersoni Stiles and Dermacentor variabilis (Say) in the Canadian Prairies were determined by passive surveillance and active collection. These findings were compared with historical records of both species, particularly in the province of Saskatchewan, where the northern distributional limits of both tick species occur. Before the 1960s, D. variabilis and D. andersoni were allopatric in Saskatchewan; however, since then, the distribution of D. variabilis has expanded westward and northward. Although the range of D. andersoni has remained relatively stable, range expansion of D. variabilis has resulted in a zone of sympatry at least 200 km wide. Twenty-nine species of mammals and three species of birds were identified as hosts for different life stages of these ticks.
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Affiliation(s)
- Shaun J Dergousoff
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, Canada S7N 5E2.
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Chavshin AR, Oshaghi MA, Vatandoost H, Yakhchali B, Raeisi A, Zarenejad F. Escherichia coli expressing a green fluorescent protein (GFP) in Anopheles stephensi: a preliminary model for paratransgenesis. Symbiosis 2013. [DOI: 10.1007/s13199-013-0231-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Stromdahl EY, Hickling GJ. Beyond Lyme: Aetiology of Tick-borne Human Diseases with Emphasis on the South-Eastern United States. Zoonoses Public Health 2012; 59 Suppl 2:48-64. [DOI: 10.1111/j.1863-2378.2012.01475.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mani RJ, Reichard MV, Morton RJ, Kocan KM, Clinkenbeard KD. Biology of Francisella tularensis subspecies holarctica live vaccine strain in the tick vector Dermacentor variabilis. PLoS One 2012; 7:e35441. [PMID: 22530023 PMCID: PMC3329428 DOI: 10.1371/journal.pone.0035441] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 03/16/2012] [Indexed: 11/20/2022] Open
Abstract
Background The γ-proteobacterium Francisella tularensis is the etiologic agent of seasonal tick-transmitted tularemia epizootics in rodents and rabbits and of incidental infections in humans. The biology of F. tularensis in its tick vectors has not been fully described, particularly with respect to its quanta and duration of colonization, tissue dissemination, and transovarial transmission. A systematic study of the colonization of Dermacentor variabilis by the F. tularensis subsp. holarctica live vaccine strain (LVS) was undertaken to better understand whether D. variabilis may serve as an inter-epizootic reservoir for F. tularensis. Methodology/Principal Findings Colony-reared larva, nymph, and adult D. variabilis were artificially fed LVS via glass capillary tubes fitted over the tick mouthparts, and the level of colonization determined by microbial culture. Larvae and nymphs were initially colonized with 8.8±0.8×101 and 1.1±0.03×103 CFU/tick, respectively. Post-molting, a significant increase in colonization of both molted nymphs and adults occurred, and LVS persisted in 42% of molted adult ticks at 126 days post-capillary tube feeding. In adult ticks, LVS initially colonized the gut, disseminated to hemolymph and salivary glands by 21 days, and persisted up to 165 days. LVS was detected in the salivary secretions of adult ticks after four days post intra-hemocoelic inoculation, and LVS recovered from salivary gland was infectious to mice with an infectious dose 50% of 3 CFU. LVS in gravid female ticks colonized via the intra-hemocoelic route disseminated to the ovaries and then to the oocytes, but the pathogen was not recovered from the subsequently-hatched larvae. Conclusions/Significance This study demonstrates that D. variabilis can be efficiently colonized with F. tularensis using artificial methods. The persistence of F. tularensis in D. variabilis suggests that this tick species may be involved in the maintenance of enzootic foci of tularemia in the central United States.
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Affiliation(s)
- Rinosh J. Mani
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Mason V. Reichard
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Rebecca J. Morton
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Katherine M. Kocan
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Kenneth D. Clinkenbeard
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
- * E-mail:
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Wasala NB, Jaworski DC. Dermacentor variabilis: characterization and modeling of macrophage migration inhibitory factor with phylogenetic comparisons to other ticks, insects and parasitic nematodes. Exp Parasitol 2012; 130:232-8. [PMID: 22306068 DOI: 10.1016/j.exppara.2011.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/11/2011] [Accepted: 12/15/2011] [Indexed: 10/14/2022]
Abstract
We have identified and characterized the full length cDNA sequence of macrophage migration inhibitory factor (MIF) from the American dog tick, Dermacentor variabilis. The nucleotide and putative amino acid sequences from this study shared a high level of sequence conservation with other tick MIFs. The bioinformatics analysis showed across species conservation of the MIF amino acid sequence in ticks, insects and nematodes. The multiple sequence alignment identified Pro 1, 3, 55; Thr 7, 112; Asn 8, 72; Ile 64, 96; Gly 65, 110, Ser 63 and Leu 87 amino acids to be highly conserved among the sequences selected for this study. Tick MIF does not have the oxidoreductase domain as found in MIFs from other animals suggesting that tick MIF is not capable of performing as an oxidoreductase. The phylogenetic analysis revealed that tick MIFs share a closer evolutionary proximity to parasitic nematode MIFs than to insect MIFs.
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Affiliation(s)
- Nalinda B Wasala
- Department of Entomology & Plant Pathology, Oklahoma State University, 127 Noble Research Center, Stillwater, OK 74078, United States
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Dermacentor andersoni transmission of Francisella tularensis subsp. novicida reflects bacterial colonization, dissemination, and replication coordinated with tick feeding. Infect Immun 2011; 79:4941-6. [PMID: 21930762 DOI: 10.1128/iai.05676-11] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ticks serve as biological vectors for a wide variety of bacterial pathogens which must be able to efficiently colonize specific tick tissues prior to transmission. The bacterial determinants of tick colonization are largely unknown, a knowledge gap attributed in large part to the paucity of tools to genetically manipulate these pathogens. In this study, we demonstrated that Francisella tularensis subsp. novicida, for which a complete two-allele transposon mutant library has been constructed, initially infects the midguts of 100% of acquisition-fed Dermacentor andersoni nymphs, with stable colonization and replication during a subsequent molt. Increased dissemination to and marked replication within the salivary gland was closely linked to a second (transmission) feed and culminated in secretion of bacteria into the saliva and successful transmission. Simultaneous testing of multiple mutants resulted in total bacterial levels similar to those observed for single mutants. However, there was evidence of a bottleneck during colonization, resulting in a founder effect in which the most successful mutant varied when comparing individual ticks. Thus, it is essential to assess mutant success at the level of the tick population rather than in individual ticks. The ability of F. tularensis subsp. novicida to recapitulate the key physiological events by which bacteria colonize and are transmitted by ixodid ticks provides a new genome-wide approach to identify the required pathogen molecules and pathways. The identification of specific genes and, more importantly, conserved pathways that function at the tick-pathogen interface will accelerate the development of new methods to block transmission.
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