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Eisen L, Saunders MEM, Kramer VL, Eisen RJ. History of the geographic distribution of the western blacklegged tick, Ixodes pacificus, in the United States. Ticks Tick Borne Dis 2024; 15:102325. [PMID: 38387162 PMCID: PMC10960675 DOI: 10.1016/j.ttbdis.2024.102325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/02/2024] [Accepted: 02/15/2024] [Indexed: 02/24/2024]
Abstract
Ixodes pacificus (the western blacklegged tick) occurs in the far western United States (US), where it commonly bites humans. This tick was not considered a species of medical concern until it was implicated in the 1980s as a vector of Lyme disease spirochetes. Later, it was discovered to also be the primary vector to humans in the far western US of agents causing anaplasmosis and hard tick relapsing fever. The core distribution of I. pacificus in the US includes California, western Oregon, and western Washington, with outlier populations reported in Utah and Arizona. In this review, we provide a history of the documented occurrence of I. pacificus in the US from the 1890s to present, and discuss associations of its geographic range with landscape, hosts, and climate. In contrast to Ixodes scapularis (the blacklegged tick) in the eastern US, there is no evidence for a dramatic change in the geographic distribution of I. pacificus over the last half-century. Field surveys in the 1930s and 1940s documented I. pacificus along the Pacific Coast from southern California to northern Washington, in the Sierra Nevada foothills, and in western Utah. County level collection records often included both immatures and adults of I. pacificus, recovered by drag sampling or from humans, domestic animals, and wildlife. The estimated geographic distribution presented for I. pacificus in 1945 by Bishopp and Trembley is similar to that presented in 2022 by the Centers for Disease Control and Prevention. There is no clear evidence of range expansion for I. pacificus, separate from tick records in new areas that could have resulted from newly initiated or intensified surveillance efforts. Moreover, there is no evidence from long-term studies that the density of questing I. pacificus ticks has increased over time in specific areas. It therefore is not surprising that the incidence of Lyme disease has remained stable in the Pacific Coast states from the early 1990s, when it became a notifiable condition, to present. We note that deforestation and deer depredation were less severe in the far western US during the 1800s and early 1900s compared to the eastern US. This likely contributed to I. pacificus maintaining stable, widespread populations across its geographic range in the far western US in the early 1900s, while I. scapularis during the same time period appears to have been restricted to a small number of geographically isolated refugia sites within its present range in the eastern US. The impact that a warming climate may have had on the geographic distribution and local abundance of I. pacificus in recent decades remains unclear.
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Affiliation(s)
- Lars Eisen
- 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, United States.
| | - Megan E M Saunders
- Vector-Borne Disease Section, California Department of Public Health, 1616 Capitol Ave, Sacramento, CA 95814, United States
| | - Vicki L Kramer
- Vector-Borne Disease Section, California Department of Public Health, 1616 Capitol Ave, Sacramento, CA 95814, United States
| | - Rebecca J Eisen
- 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, United States
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Karshima SN, Ahmed MI, Mohammed KM, Pam VA, Momoh-Abdullateef H, Gwimi BP. Worldwide meta-analysis on Anaplasma phagocytophilum infections in animal reservoirs: Prevalence, distribution and reservoir diversity. Vet Parasitol Reg Stud Reports 2023; 38:100830. [PMID: 36725159 DOI: 10.1016/j.vprsr.2022.100830] [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: 05/04/2022] [Revised: 12/06/2022] [Accepted: 12/30/2022] [Indexed: 01/01/2023]
Abstract
A wide range of vertebrate species are competent reservoirs of Anaplasma phagocytophilum, where the pathogen is maintained in the enzootic cycle and transmitted to humans through activities of tick vectors. An insight into the role and diversity of these reservoirs is vital in understanding the epidemiology of this pathogen. Here, we determined the prevalence, distribution and reservoir diversity of A. phagocytophilum using a systematic review and meta-analysis. Data pooling was performed by the random-effects model, heterogeneity was assessed by the Cochran's Q-test and publication bias by Egger's regression test. Eighty-nine studies from 33 countries across 5 continents revealed A. phagocytophilum pooled prevalence of 15.18% (95% CI: 11.64, 19.57). Continental estimates varied significantly (p < 0.0001), with a range of 2.88% (95% CI: 0.25, 26.20) in South America to 19.91% (95% CI: 13.57, 28.24) in Europe. Country-based estimates ranged between 2.93% (95% CI: 1.17, 7.16) in Slovakia and 71.58% (95% CI: 25.91, 94.77) in Norway. Studies on A. phagocytophilum were concentrated in Europe (51.69%; 46/89) by continent and the USA (22.47%; 20/89) by country. Prevalence in wildlife (17.64%; 95% CI: 12.21-28.59) was significantly higher (p < 0.001) than that among domestic animals (10.68%; 95% CI: 6.61-16.83). Diverse species of wildlife, domestic animals and birds were infected by A. phagocytophilum. To curtail the public health, veterinary and economic consequences of A. phagocytophilum infections, we recommend an all-inclusive epidemiological approach that targets the human, animal and environmental components of the disease.
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Affiliation(s)
- Solomon Ngutor Karshima
- Department of Veterinary Public Health and Preventive Medicine, Federal University of Agriculture Zuru, PMB 28 Zuru, Kebbi State, Nigeria.
| | - Musa Isiyaku Ahmed
- Department of Veterinary Parasitology and Entomology, Federal University of Agriculture Zuru, PMB 28 Zuru, Kebbi State, Nigeria
| | - Kaltume Mamman Mohammed
- Department of Veterinary Public Health and Preventive Medicine, Federal University of Agriculture Zuru, PMB 28 Zuru, Kebbi State, Nigeria
| | - Victoria Adamu Pam
- Department of Zoology, Federal University Lafia, Lafia PMB 146, Nasarawa State, Nigeria
| | - Habiba Momoh-Abdullateef
- Department of Animal Health, Federal College of Animal Health and Production Technology, PMB 001, Vom, Plateau State, Nigeria
| | - Bulus Peter Gwimi
- Department of Veterinary Public Health and Preventive Medicine, Federal University of Agriculture Zuru, PMB 28 Zuru, Kebbi State, Nigeria
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Karshima SN, Ahmed MI, Kogi CA, Iliya PS. Anaplasma phagocytophilum infection rates in questing and host-attached ticks: a global systematic review and meta-analysis. Acta Trop 2022; 228:106299. [PMID: 34998998 DOI: 10.1016/j.actatropica.2021.106299] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 12/17/2021] [Accepted: 12/29/2021] [Indexed: 12/15/2022]
Abstract
Anaplasma phagocytophilum causes a multi-organ non-specific febrile illness referred to as human granulocytic anaplasmosis. The epidemiologic risk of the pathogen is underestimated despite human encroachment into the natural habitats of ticks. In this study, we performed a systematic review and meta-analysis to determine the global infection rates and distribution of A. phagocytophilum in tick vectors. We pooled data using the random-effects model, assessed individual study quality using the Joanna Briggs Institute critical appraisal instrument for prevalence studies and determined heterogeneity and across study bias using Cochran's Q-test and Egger's regression test respectively. A total of 126 studies from 33 countries across 4 continents reported A. phagocytophilum estimated infection rate of 4.76% (9453/174,967; 95% CI: 3.96, 5.71). Estimated IRs across sub-groups varied significantly (p <0.05) with a range of 1.95 (95% CI: 0.63, 5.86) to 7.15% (95% CI: 5.31, 9.56). Country-based IRs ranged between 0.42 (95% CI: 0.22, 0.80) in Belgium and 37.54% (95% CI: 0.72, 98.03) in Norway. The highest number of studies on A. phagocytophilum were in Europe (82/126) by continent and the USA (33/126) by country. The risk of transmitting this pathogens from ticks to animals and humans exist and therefore, we recommend the use of chemical and biological control measures as well as repellents and protective clothing by occupationally exposed individuals to curtail further transmission of the pathogen to humans and animals.
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El Hamiani Khatat S, Daminet S, Duchateau L, Elhachimi L, Kachani M, Sahibi H. Epidemiological and Clinicopathological Features of Anaplasma phagocytophilum Infection in Dogs: A Systematic Review. Front Vet Sci 2021; 8:686644. [PMID: 34250067 PMCID: PMC8260688 DOI: 10.3389/fvets.2021.686644] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
Anaplasma phagocytophilum is a worldwide emerging zoonotic tick-borne pathogen transmitted by Ixodid ticks and naturally maintained in complex and incompletely assessed enzootic cycles. Several studies have demonstrated an extensive genetic variability with variable host tropisms and pathogenicity. However, the relationship between genetic diversity and modified pathogenicity is not yet understood. Because of their proximity to humans, dogs are potential sentinels for the transmission of vector-borne pathogens. Furthermore, the strong molecular similarity between human and canine isolates of A. phagocytophilum in Europe and the USA and the positive association in the distribution of human and canine cases in the USA emphasizes the epidemiological role of dogs. Anaplasma phagocytophilum infects and survives within neutrophils by disregulating neutrophil functions and evading specific immune responses. Moreover, the complex interaction between the bacterium and the infected host immune system contribute to induce inflammatory injuries. Canine granulocytic anaplasmosis is an acute febrile illness characterized by lethargy, inappetence, weight loss and musculoskeletal pain. Hematological and biochemistry profile modifications associated with this disease are unspecific and include thrombocytopenia, anemia, morulae within neutrophils and increased liver enzymes activity. Coinfections with other tick-borne pathogens (TBPs) may occur, especially with Borrelia burgdorferi, complicating the clinical presentation, diagnosis and response to treatment. Although clinical studies have been published in dogs, it remains unclear if several clinical signs and clinicopathological abnormalities can be related to this infection.
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Affiliation(s)
- Sarah El Hamiani Khatat
- Department of Medicine, Surgery and Reproduction, Hassan II Institute of Agronomy and Veterinary Medicine, Rabat, Morocco
| | - Sylvie Daminet
- Department of Companion Animals, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Luc Duchateau
- Department of Comparative Physiology and Biometrics, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Latifa Elhachimi
- Department of Pathology and Veterinary Public Health, Unit of Parasitology, Hassan II Institute of Agronomy and Veterinary Medicine, Rabat, Morocco
| | - Malika Kachani
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA, United States
| | - Hamid Sahibi
- Department of Pathology and Veterinary Public Health, Unit of Parasitology, Hassan II Institute of Agronomy and Veterinary Medicine, Rabat, Morocco
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López-Pérez AM, Plourde B, Smith K, Rubino F, Pascoe E, Smith O, Foley J. Impacts of Timber Harvest on Communities of Small Mammals, Ticks, and Tick-Borne Pathogens in a High-Risk Landscape in Northern California. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1171-1187. [PMID: 33459790 DOI: 10.1093/jme/tjaa297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Indexed: 06/12/2023]
Abstract
Timber harvest may impact tick-borne disease by affecting small mammal and tick community structures. We assessed tick and small mammal populations in older second-growth redwood (Sequoia sempervirens (D. Don) Endl) habitat at two harvested sites in Santa Cruz County, California, where local risk of tick-borne disease is high and determined the prevalence of tick-borne pathogens in ticks. After single-tree removal harvest in 2014, there was a modest reduction in canopy, primarily toward the end of the study. Harvested sites showed strong reductions in California mouse (Peromyscus californicus, (Gambel)) captures 2-yr after harvest, resolving such that treatments and controls were comparable by the end of the study. Following harvest, treated sites experienced a transient decreased tick infestation while control plots experienced an increase. Ixodes angustus (Neumann) infestation probability on harvested plots decreased immediately after harvest, increasing with time but remaining lower than control plots, whereas I. pacificus (Cooley and Kohls) prevalence was higher shortly after the harvest on harvested plots, and continued to increase. Mean abundance of ticks on vegetation increased on control plots. We detected Borrelia burgdorferi ((Johnson et al.) Baranton) and Anaplasma phagocytophilum ((Foggie 1949) Dumler) in 3.8 and 3.1% of ticks on rodents, but no differences were associated with harvest. Impacts of forest harvest on tick-borne disease depend on removal practice and intensity, whether or not hosts are habitat specialists, and whether or not ticks are host specialists.
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Affiliation(s)
- Andres M López-Pérez
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA
| | - Benjamin Plourde
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA
| | | | - Francesca Rubino
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA
| | - Emily Pascoe
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA
| | - Olivia Smith
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA
| | - Janet Foley
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA
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Salomon J, Hamer SA, Swei A. A Beginner's Guide to Collecting Questing Hard Ticks (Acari: Ixodidae): A Standardized Tick Dragging Protocol. JOURNAL OF INSECT SCIENCE (ONLINE) 2020; 20:11. [PMID: 33135760 PMCID: PMC7604844 DOI: 10.1093/jisesa/ieaa073] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Indexed: 05/22/2023]
Abstract
Tick-borne diseases are emerging globally, necessitating increased research and coordination of tick surveillance practices. The most widely used technique for active collection of host-seeking, human-biting tick vectors is 'tick dragging', by which a cloth is dragged across the top of the vegetation or forest floor and regularly checked for the presence of ticks. Use of variable dragging protocols limits the ability of researchers to combine data sets for comparative analyses or determine patterns and trends across different spatial and temporal scales. Standardization of tick drag collection and reporting methodology will greatly benefit the field of tick-pathogen studies. Based on the recommendations of the Center for Disease Control and Prevention and other ecological considerations, we propose that tick dragging should be conducted to sample at least 750 m2 along linear transects when habitat allows in a manner that reduces bias in the sampled area, and report density of each tick species and life stage separately. A protocol for constructing a standard drag cloth, establishing linear transects, and drag sampling is presented, along with a downloadable datasheet that can be modified to suit the needs of different projects. Efforts to align tick surveillance according to these standard best practices will help generate robust data on tick population biology.
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Affiliation(s)
- Jordan Salomon
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX
| | - Sarah A Hamer
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX
| | - Andrea Swei
- Department of Biology, San Francisco State University, San Francisco, CA
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Hahn MB, Disler G, Durden LA, Coburn S, Witmer F, George W, Beckmen K, Gerlach R. Establishing a baseline for tick surveillance in Alaska: Tick collection records from 1909-2019. Ticks Tick Borne Dis 2020; 11:101495. [PMID: 32723642 PMCID: PMC7447289 DOI: 10.1016/j.ttbdis.2020.101495] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 10/24/2022]
Abstract
The expanding geographic ranges of tick species that are known pathogen vectors can have implications for human, domestic animal, and wildlife health. Although Alaska is home to several hard tick species, it has historically been outside of the range of the most common medically important ticks in the contiguous United States and western Canada. To assess the status of tick species establishment in the state and to provide a baseline for tracking future change in the distribution of ticks, we reviewed and compiled historical tick records and summarized recent tick occurrence records collected through the development of the Alaska Submit-A-Tick Program and through tick drag sampling at sentinel sites in southcentral Alaska. Between 1909-2019, there were 1190 tick records representing 4588 individual ticks across 15 species in Alaska. The majority of ticks were species historically found in Alaska: Haemaphysalis leporispalustris, Ixodes angustus, Ixodes auritulus, Ixodes howelli, Ixodes signatus, and Ixodes uriae. Over half of all tick records in the state were collected in the last 10 yr. During this time, the number of tick records and the number of tick species recorded in Alaska each year has increased substantially. Between 2010-2019, there were 611 tick records representing 1921 individual ticks. The most common hosts for reported ticks were domestic animals (n = 343, 56 %) followed by small wild mammals (n = 147, 24 %), humans (n = 49, 8%), and wild birds (n = 31, 5%). Less than 5% of records (n = 25) were of unattached ticks found in the environment. Since 2007, non-native tick species have been documented in the state every year, including Amblyomma americanum, Dermacentor andersoni, Dermacentor occidentalis, Dermacentor variabilis, Ixodes pacificus, Ixodes ricinus, Ixodes scapularis, Ixodes texanus, and Rhipicephalus sanguineus sensu lato (s.l.). Almost half of the records (n = 68, 48 %) of non-native tick species from 2010 to 2019 represented ticks found on a host (usually a dog or a human) that had traveled outside of Alaska in the two weeks prior to collection. However, A. americanum, D. variabilis, I. pacificus, I. texanus, and R. sanguineus s.l. have been found on humans and domestic animals in Alaska without reported recent travel. In particular, there is evidence to suggest that there is local establishment of R. sanguineus s.l. in Alaska. A tick species historically found in the state, I. angustus was frequently found on human and dogs, suggesting a potential role as a bridge vector of pathogens. Given the inconsistency of tick monitoring in Alaska over the past century, it is difficult to draw many conclusions from temporal trends in the data. Continued monitoring through the Alaska Submit-A-Tick Program will allow a more accurate assessment of the changing risk of ticks and tick-borne diseases in the state and provide information for setting clinical and public health guidelines for tick-borne disease prevention.
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Affiliation(s)
- Micah B Hahn
- Institute for Circumpolar Health, University of Alaska-Anchorage, 3211 Providence Drive, BOC3 270, Anchorage, Alaska 99508, United States.
| | - Gale Disler
- Division of Population Health Sciences, University of Alaska-Anchorage, United States.
| | - Lance A Durden
- Department of Biology, Georgia Southern University, 4324 Old Register Road, Statesboro, GA 30458, United States.
| | - Sarah Coburn
- Alaska Department of Environmental Conservation, Office of the State Veterinarian, 5251 Dr. Martin Luther King Jr. Ave, Anchorage, AK 99507, United States.
| | - Frank Witmer
- Department of Computer Science and Engineering, University of Alaska-Anchorage, United States.
| | - William George
- Department of Biological Sciences, University of Alaska-Anchorage, United States.
| | - Kimberlee Beckmen
- Alaska Department of Fish and Game, Division of Wildlife Conservation, Wildlife Health and Disease, Surveillance Program, 1300 College Road, Fairbanks, Alaska 99701, United States.
| | - Robert Gerlach
- Alaska Department of Environmental Conservation, Office of the State Veterinarian, 5251 Dr. Martin Luther King Jr. Ave, Anchorage, AK 99507, United States.
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Dahmani M, Anderson JF, Sultana H, Neelakanta G. Rickettsial pathogen uses arthropod tryptophan pathway metabolites to evade reactive oxygen species in tick cells. Cell Microbiol 2020; 22:e13237. [PMID: 32562372 DOI: 10.1111/cmi.13237] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/10/2020] [Accepted: 06/13/2020] [Indexed: 12/16/2022]
Abstract
Reactive oxygen species (ROS) that are induced upon pathogen infection plays an important role in host defence. The rickettsial pathogen Anaplasma phagocytophilum, which is primarily transmitted by Ixodes scapularis ticks in the United States, has evolved many strategies to escape ROS and survive in mammalian cells. However, little is known on the role of ROS in A. phagocytophilum infection in ticks. Our results show that A. phagocytophilum and hemin induce activation of l-tryptophan pathway in tick cells. Xanthurenic acid (XA), a tryptophan metabolite, supports A. phagocytophilum growth in tick cells through inhibition of tryptophan dioxygenase (TDO) activity leading to reduced l-kynurenine levels that subsequently affects build-up of ROS. However, hemin supports A. phagocytophilum growth in tick cells by inducing TDO activity leading to increased l-kynurenine levels and ROS production. Our data reveal that XA and kynurenic acid (KA) chelate hemin. Furthermore, treatment of tick cells with 3-hydroxyl l-kynurenine limits A. phagocytophilum growth in tick cells. RNAi-mediated knockdown of kynurenine aminotransferase expression results in increased ROS production and reduced A. phagocytophilum burden in tick cells. Collectively, these results suggest that l-tryptophan pathway metabolites influence A. phagocytophilum survival by affecting build up of ROS levels in tick cells.
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Affiliation(s)
- Mustapha Dahmani
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA.,Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - John F Anderson
- Department of Entomology, Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Hameeda Sultana
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA.,Center for Molecular Medicine, Old Dominion University, Norfolk, VA, USA
| | - Girish Neelakanta
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA.,Center for Molecular Medicine, Old Dominion University, Norfolk, VA, USA
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Tsai KH, Chung LH, Chien CH, Tung YJ, Wei HY, Yen TY, Shu PY, Wang HC. Human granulocytic anaplasmosis in Kinmen, an offshore island of Taiwan. PLoS Negl Trop Dis 2019; 13:e0007728. [PMID: 31539395 PMCID: PMC6774531 DOI: 10.1371/journal.pntd.0007728] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 10/02/2019] [Accepted: 08/23/2019] [Indexed: 12/22/2022] Open
Abstract
Background Human granulocytic anaplasmosis, a tick-borne infection caused by Anaplasma phagocytophilum, has received scant attention, while scrub typhus, a mite-transmitted disease caused by Orientia tsutsugamushi, is the most common rickettsiosis in Taiwan. The clinical presentations of both diseases are characterized by undifferentiated fever, headache and malaise. Moreover, both pathogens have been detected in small mammals that serve as hosts for chiggers and ticks in the wild. The objective of the present study was to investigate whether human granulocytic anaplasmosis occurs in Taiwan. Methodology/Principal findings Blood samples from 274 patients suspected of having scrub typhus in Kinmen, an offshore island of Taiwan, in 2011 and 2012 were retrospectively examined by immunofluorescence assays. IgG antibodies reactive with Anaplasma phagocytophilum was found in 31.8% (87/274) of the patients. Paired serology identified 3 patients with human granulocytic anaplasmosis and 8 patients with coinfection with O. tsutsugamushi and A. phagocytophilum. Laboratory tests showed that elevated serum ALT/AST, creatinine, and BUN levels were observed in patients with anaplasmosis and coinfection, but elevated serum CRP levels, thrombocytopenia, and anemia were only observed in coinfected patients. PCR detected A. phagocytophilum 16S rDNA and p44/msp2 in 2 patients. The phylogenetic analysis suggested that the replicons of the 16S rDNA shared high sequence similarity with the reference sequences in the Korea, USA, Japan, and China. The amplicons of p44/msp2 were close to those of the human variants identified in the USA and Japan. Conclusions Our findings indicated that A. phagocytophilum infection was prevalent but unrecognized in Taiwan. Human granulocytic anaplasmosis is a tick-borne rickettsial infection caused by Anaplasma phagocytophilum. Although most cases resolve readily, life-threatening complications can occur without prompt antibiotic treatment. The major difficulty in diagnosing human granulocytic anaplasmosis is due to the nonspecific nature of the symptoms. Given that scrub typhus is the most frequently reported rickettsial disease in Taiwan and shares similar early clinical signs with anaplasmosis, we retrospectively examined blood samples from patients with suspected diagnoses of scrub typhus in 2011 and 2012. While serological evidence of potential past exposure was found in as many as 31.8% (87/274) of the patients, current or recent anaplasmosis was supported by seroconversion in 11 patients, including 8 patients coinfected with scrub typhus. Anaplasma phagocytophilum DNA was detected in acute phase samples, and the amplified fragments were phylogenetically close to those of variants in the Korea, the USA, Japan, and China. Herein, for the first time, we confirmed the presence of human granulocytic anaplasmosis in Taiwan. By reporting coinfections with anaplasmosis and scrub typhus, the study further highlighted the health risk of increasing contact with wild rodents.
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Affiliation(s)
- Kun-Hsien Tsai
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei, Taiwan
- Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Lo-Hsuan Chung
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Chia-Hao Chien
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
| | - Yu-Jung Tung
- Kinmen Hospital, Ministry of Health and Welfare, Kinmen, Taiwan
| | - Hsin-Yi Wei
- Taipei Regional Center, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
| | - Tsai-Ying Yen
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Pei-Yun Shu
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
- * E-mail: (PYS); (HCW)
| | - Hsi-Chieh Wang
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei, Taiwan
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
- * E-mail: (PYS); (HCW)
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10
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Occi JL, Egizi AM, Robbins RG, Fonseca DM. Annotated List of the Hard Ticks (Acari: Ixodida: Ixodidae) of New Jersey. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:589-598. [PMID: 30753552 DOI: 10.1093/jme/tjz010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Indexed: 06/09/2023]
Abstract
Standardized tick surveillance requires an understanding of which species may be present. After a thorough review of the scientific literature, as well as government documents, and careful evaluation of existing accessioned tick collections (vouchers) in museums and other repositories, we have determined that the verifiable hard tick fauna of New Jersey (NJ) currently comprises 11 species. Nine are indigenous to North America and two are invasive, including the recently identified Asian longhorned tick, Haemaphysalis longicornis (Neumann, 1901). For each of the 11 species, we summarize NJ collection details and review their known public health and veterinary importance and available information on seasonality. Separately considered are seven additional species that may be present in the state or become established in the future but whose presence is not currently confirmed with NJ vouchers. We compare our list of hard ticks in NJ with those from neighboring states (Connecticut, New York, Pennsylvania, Delaware, and Maryland), discuss the importance of vouchers in tick research and surveillance, and examine the likelihood and public health consequences of additional hard tick species becoming established in NJ.
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Affiliation(s)
- James L Occi
- Center for Vector Biology, Department of Entomology, Rutgers University, New Brunswick
| | - Andrea M Egizi
- Center for Vector Biology, Department of Entomology, Rutgers University, New Brunswick
- Tick-borne Diseases Laboratory, Monmouth County Mosquito Control Division, Tinton Falls
| | - Richard G Robbins
- Walter Reed Biosystematics Unit, Department of Entomology, Smithsonian Institution, MSC, MRC, Suitland
| | - Dina M Fonseca
- Center for Vector Biology, Department of Entomology, Rutgers University, New Brunswick
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11
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Benevenute JL, Dumler JS, Ogrzewalska M, Roque ALR, Mello VVC, de Sousa KCM, Gonçalves LR, D'Andrea PS, de Sampaio Lemos ER, Machado RZ, André MR. Assessment of a quantitative 5' nuclease real-time polymerase chain reaction using groEL gene for Ehrlichia and Anaplasma species in rodents in Brazil. Ticks Tick Borne Dis 2017; 8:646-656. [PMID: 28457822 DOI: 10.1016/j.ttbdis.2017.04.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/13/2017] [Accepted: 04/14/2017] [Indexed: 12/22/2022]
Abstract
New genotypes of Anaplasmataceae agents have been detected in wild carnivores, birds and deer in Brazil. The present work aimed to investigate the presence of Ehrlichia and Anaplasma species in rodents sampled in Brazil. Additionally, a newly designed quantitative 5' nuclease real-time multiplex PCR for Ehrlichia and Anaplasma spp. detection based on groEL gene amplification was designed, showing high specificity and sensitivity (10 groEL fragment copy/μL). Between 2000 and 2011, different rodent species [n=60] were trapped in 5 Brazilian biomes. Among 458 rodent spleen samples, 0.4% (2/458) and 2.4% (11/458) were positive for Ehrlichia and Anaplasma spp., respectively. Of 458 samples, 2.0% (9/458) and 1.1% (5/458) were positive for Anaplasma sp. and Ehrlichia sp., respectively, using conventional 16S rRNA PCR assays. Maximum Likelihood phylogenetic analyse based on a small region of 16S rRNA genes positioned the Anaplasma genotypes in rodents near Anaplasma phagocytophilum or Anaplasma marginale and Anaplasma odocoilei isolates. Ehrlichia genotypes were closely related to E. canis. There was a low occurrence of Anaplasma and Ehrlichia in wild and synanthropic rodents in Brazil, suggesting the circulation of new genotypes of these agents in rodents in the studied areas.
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Affiliation(s)
- Jyan Lucas Benevenute
- Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal, SP, Brazil
| | - John Stephen Dumler
- Johns Hopkins School of Medicine, Baltimore, Maryland, USA; Uniformed Services University, Bethesda, Maryland, USA
| | - Maria Ogrzewalska
- Laboratório de Hantaviroses e Rickettsioses, Instituto Oswaldo Cruz/Fiocruz, Rio de Janeiro, Brazil
| | | | | | | | - Luiz Ricardo Gonçalves
- Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal, SP, Brazil
| | - Paulo Sérgio D'Andrea
- Laboratório de Biologia e Parasitologia de Mamíferos Silvestres Reservatórios, Instituto Oswaldo Cruz/Fiocruz, Rio de Janeiro, Brazil
| | | | - Rosangela Zacarias Machado
- Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal, SP, Brazil
| | - Marcos Rogério André
- Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal, SP, Brazil.
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12
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Battilani M, De Arcangeli S, Balboni A, Dondi F. Genetic diversity and molecular epidemiology of Anaplasma. INFECTION GENETICS AND EVOLUTION 2017; 49:195-211. [PMID: 28122249 DOI: 10.1016/j.meegid.2017.01.021] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 01/18/2017] [Accepted: 01/19/2017] [Indexed: 11/25/2022]
Abstract
Anaplasma are obligate intracellular bacteria of cells of haematopoietic origin and are aetiological agents of tick-borne diseases of both veterinary and medical interest common in both tropical and temperate regions. The recent disclosure of their zoonotic potential has greatly increased interest in the study of these bacteria, leading to the recent reorganisation of Rickettsia taxonomy and to the possible discovery of new species belonging to the genus Anaplasma. This review is particularly focused on the common and unique characteristics of Anaplasma marginale and Anaplasma phagocytophilum, with an emphasis on genetic diversity and evolution, and the main distinguishing features of the diseases caused by the different Anaplasma spp. are described as well.
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Affiliation(s)
- Mara Battilani
- Department of Veterinary Medical Sciences, Alma Mater Studiorum - University of Bologna, Via Tolara di Sopra, 50, 40064 Ozzano Emilia, Bo, Italy.
| | - Stefano De Arcangeli
- Department of Veterinary Medical Sciences, Alma Mater Studiorum - University of Bologna, Via Tolara di Sopra, 50, 40064 Ozzano Emilia, Bo, Italy
| | - Andrea Balboni
- Department of Veterinary Medical Sciences, Alma Mater Studiorum - University of Bologna, Via Tolara di Sopra, 50, 40064 Ozzano Emilia, Bo, Italy
| | - Francesco Dondi
- Department of Veterinary Medical Sciences, Alma Mater Studiorum - University of Bologna, Via Tolara di Sopra, 50, 40064 Ozzano Emilia, Bo, Italy
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13
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Stephenson N, Wong J, Foley J. Host, habitat and climate preferences of Ixodes angustus (Acari: Ixodidae) and infection with Borrelia burgdorferi and Anaplasma phagocytophilum in California, USA. EXPERIMENTAL & APPLIED ACAROLOGY 2016; 70:239-252. [PMID: 27416728 DOI: 10.1007/s10493-016-0068-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 07/05/2016] [Indexed: 06/06/2023]
Abstract
The Holarctic tick Ixodes angustus is a competent vector for Borrelia burgdorferi, the etiologic agent of Lyme disease, and possibly Anaplasma phagocytophilum, the etiologic agent of granulocytic anaplasmosis, as well. From 2005 to 2013, we collected host-feeding I. angustus individuals from live-trapped small mammals and by flagging vegetation from 12 study sites in northern and central California, and tested for B. burgdorferi sensu lato, A. phagocytophilum, and Rickettsia spp. DNA by real-time PCR. Among 261 I. angustus collected (259 from hosts and two by flagging), the most common hosts were tree squirrels (20 % of ticks) and chipmunks (37 %). The PCR-prevalence for A. phagocytophilum and B. burgdorferi in ticks was 2 % and zero, respectively. The minimum infection prevalence on pooled DNA samples was 10 % for Rickettsia spp. DNA sequencing of the ompA gene identified this rickettsia as Candidatus Rickettsia angustus, a putative endosymbiont. A zero-inflated negative binomial mixed effects model was used to evaluate geographical and climatological predictors of I. angustus burden. When host species within study site and season within year were included in the model as nested random effects, all significant variables revealed that I. angustus burden increased as temperature decreased. Together with published data, these findings suggest that I. angustus is a host generalist, has a broad geographic distribution, is more abundant in areas with lower temperature within it's range, and is rarely infected with the pathogens A. phagocytophilum and B. burgdorferi.
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Affiliation(s)
- Nicole Stephenson
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA.
| | - Johnny Wong
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA
| | - Janet Foley
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA
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14
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Parallelisms and Contrasts in the Diverse Ecologies of the Anaplasma phagocytophilum and Borrelia burgdorferi Complexes of Bacteria in the Far Western United States. Vet Sci 2016; 3:vetsci3040026. [PMID: 29056734 PMCID: PMC5606591 DOI: 10.3390/vetsci3040026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 09/03/2016] [Accepted: 09/14/2016] [Indexed: 11/17/2022] Open
Abstract
Anaplasma phagocytophilum and Borrelia burgdorferi are two tick-borne bacteria that cause disease in people and animals. For each of these bacteria, there is a complex of closely related genospecies and/or strains that are genetically distinct and have been shown through both observational and experimental studies to have different host tropisms. In this review we compare the known ecologies of these two bacterial complexes in the far western USA and find remarkable similarities, which will help us understand evolutionary histories and coadaptation among vertebrate host, tick vector, and bacteria. For both complexes, sensu stricto genospecies (those that infect humans) share a similar geographic range, are vectored mainly by ticks in the Ixodes ricinus-complex, utilize mainly white-footed mice (Peromyscus leucopus) as a reservoir in the eastern USA and tree squirrels in the far west, and tend to be generalists, infecting a wider variety of vertebrate host species. Other sensu lato genospecies within each complex are generally more specialized, occurring often in local enzootic cycles within a narrow range of vertebrate hosts and specialized vector species. We suggest that these similar ecologies may have arisen through utilization of a generalist tick species as a vector, resulting in a potentially more virulent generalist pathogen that spills over into humans, vs. utilization of a specialized tick vector on a particular vertebrate host species, promoting microbe specialization. Such tight host-vector-pathogen coupling could also facilitate high enzootic prevalence and the evolution of host immune-tolerance and bacterial avirulence.
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15
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Nieto NC, Salkeld DJ. Epidemiology and Genetic Diversity of Anaplasma phagocytophilum in the San Francisco Bay Area, California. Am J Trop Med Hyg 2016; 95:50-4. [PMID: 27139447 DOI: 10.4269/ajtmh.15-0707] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 02/17/2016] [Indexed: 11/07/2022] Open
Abstract
In California, the agent of human granulocytic anaplasmosis (HGA), Anaplasma phagocytophilum, is transmitted by western black-legged ticks (Ixodes pacificus). Cases of HGA are infrequent in California but do occur annually. We investigated nymphal and adult western black-legged tick populations in 20 recreational areas in California's San Francisco Bay Area (Marin, Napa, San Mateo, Santa Clara, Santa Cruz, and Sonoma counties). Overall, prevalence of A. phagocytophilum in adult ticks was 0.8% (11/1,465), and in nymphal ticks was 4.2% (24/568), though presence was patchy and prevalence varied locally. We detected significant sequence variation in our quantitative polymerase chain reaction (qPCR)-positive samples. This included four sequences that grouped within a clade that contains clinical human and veterinary isolates as well as four others that grouped with sequences from PCR-positive lizards from northern California. Tick populations in our study sites harbor genetically diverse strains of A. phagocytophilum, which may influence potential risk in the region.
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Affiliation(s)
- Nathan C Nieto
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona.
| | - Daniel J Salkeld
- Department of Biology, Colorado State University, Fort Collins, Colorado. Woods Center for the Environment, Stanford University, Stanford, California
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16
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Dugat T, Lagrée AC, Maillard R, Boulouis HJ, Haddad N. Opening the black box of Anaplasma phagocytophilum diversity: current situation and future perspectives. Front Cell Infect Microbiol 2015; 5:61. [PMID: 26322277 PMCID: PMC4536383 DOI: 10.3389/fcimb.2015.00061] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 07/31/2015] [Indexed: 01/28/2023] Open
Abstract
Anaplasma phagocytophilum is a zoonotic obligate intracellular bacterium known to be transmitted by ticks belonging to the Ixodes persulcatus complex. This bacterium can infect several mammalian species, and is known to cause diseases with variable symptoms in many domestic animals. Specifically, it is the causative agent of tick-borne fever (TBF), a disease of important economic impact in European domestic ruminants, and human granulocytic anaplasmosis (HGA), an emerging zoonotic disease in Asia, USA and Europe. A. phagocytophilum epidemiological cycles are complex and involve different ecotypes, vectors, and mammalian host species. Moreover, the epidemiology of A. phagocytophilum infection differs greatly between Europe and the USA. These different epidemiological contexts are associated with considerable variations in bacterial strains. Until recently, few A. phagocytophilum molecular typing tools were available, generating difficulties in completely elucidating the epidemiological cycles of this bacterium. Over the last few years, many A. phagocytophilum typing techniques have been developed, permitting in-depth epidemiological exploration. Here, we review the current knowledge and future perspectives regarding A. phagocytophilum epidemiology and phylogeny, and then focus on the molecular typing tools available for studying A. phagocytophilum genetic diversity.
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Affiliation(s)
- Thibaud Dugat
- Laboratoire de Santé Animale, UMR Biologie Moléculaire et Immunologie Parasitaires, Agence Nationale de Sécurité Sanitaire de L'alimentation, de L'environnement et du Travail, Université Paris-Est Paris, France
| | - Anne-Claire Lagrée
- UMR Biologie Moléculaire et Immunologie Parasitaires, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est Paris, France
| | - Renaud Maillard
- UMR Biologie Moléculaire et Immunologie Parasitaires, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est Paris, France ; Unité Pathologie des Ruminants, Ecole Nationale Vétérinaire de Toulouse Toulouse, France
| | - Henri-Jean Boulouis
- UMR Biologie Moléculaire et Immunologie Parasitaires, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est Paris, France
| | - Nadia Haddad
- UMR Biologie Moléculaire et Immunologie Parasitaires, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est Paris, France
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17
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Foley J, Piovia-Scott J. Vector biodiversity did not associate with tick-borne pathogen prevalence in small mammal communities in northern and central California. Ticks Tick Borne Dis 2014; 5:299-304. [PMID: 24582513 DOI: 10.1016/j.ttbdis.2013.12.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 10/28/2013] [Accepted: 12/02/2013] [Indexed: 11/25/2022]
Abstract
Vector and host abundance affect infection transmission rates, prevalence, and persistence in communities. Biological diversity in hosts and vectors may provide "rescue" hosts which buffer against pathogen extinction and "dilution" hosts which reduce the force of infection in communities. Anaplasma phagocytophilum is a tick-transmitted zoonotic pathogen that circulates in small mammal and tick communities characterized by varying levels of biological diversity. We examined the prevalence of A. phagocytophilum in Ixodes spp. ticks in 11 communities in northern and central California. A total of 1020 ticks of 8 species was evaluated. Five percent of ticks (5 species) were PCR-positive, with the highest prevalence (6-7%) in I. pacificus and I. ochotonae. In most species, adults had a higher prevalence than nymphs or larvae. PCR prevalence varied between 0% and 40% across sites; the infection probability in ticks increased with infestation load and prevalence in small mammals, but not tick species richness, diversity, evenness, or small mammal species richness. No particular tick species was likely to "rescue" infection in the community; rather the risk of A. phagocytophilum infection is related to exposure to particular tick species and life stages, and overall tick abundance.
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Affiliation(s)
- Janet Foley
- School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA.
| | - Jonah Piovia-Scott
- School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA
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18
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Rejmanek D, Freycon P, Bradburd G, Dinstell J, Foley J. Unique strains of Anaplasma phagocytophilum segregate among diverse questing and non-questing Ixodes tick species in the western United States. Ticks Tick Borne Dis 2013; 4:482-7. [PMID: 23994335 DOI: 10.1016/j.ttbdis.2013.06.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 06/24/2013] [Accepted: 06/25/2013] [Indexed: 11/19/2022]
Abstract
The emerging tick-borne pathogen Anaplasma phagocytophilum infects humans, domestic animals, and wildlife throughout the Holarctic. In the western US, the ecology of A. phagocytophilum is particularly complex, with multiple pathogen strains, tick vectors, and reservoir hosts. A recent phylogenetic analysis of A. phagocytophilum strains isolated from various small mammal hosts in California documented distinct clustering of woodrat strains separate from sciurid (chipmunk and squirrel) strains. Here, we identified strains of A. phagocytophilum in various Ixodes tick species in California and related these genotypes to those found among reservoir and clinical hosts from the same areas. The sequences from all of the nidicolous (nest-dwelling) Ixodes ticks grouped within a clade that also contained all of the woodrat-origin A. phagocytophilum strains. Two of the I. pacificus sequences were also grouped within this woodrat clade, while the remaining five belonged to a less genetically diverse clade that included several sciurid-origin strains as well as a dog, a horse, and a human strain. By comparing A. phagocytophilum strains from multiple sources concurrently, we were able to gain a clearer picture of how A. phagocytophilum strains in the western US are partitioned, which hosts and vectors are most likely to be infected with a particular strain, and which tick species and reservoir hosts pose the greatest health risk to humans and domestic animals.
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Affiliation(s)
- Daniel Rejmanek
- Davis School of Veterinary Medicine, University of California, Department of Medicine and Epidemiology, Davis, CA 95616, USA.
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19
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Stuen S, Granquist EG, Silaghi C. Anaplasma phagocytophilum--a widespread multi-host pathogen with highly adaptive strategies. Front Cell Infect Microbiol 2013; 3:31. [PMID: 23885337 PMCID: PMC3717505 DOI: 10.3389/fcimb.2013.00031] [Citation(s) in RCA: 368] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 06/30/2013] [Indexed: 11/21/2022] Open
Abstract
The bacterium Anaplasma phagocytophilum has for decades been known to cause the disease tick-borne fever (TBF) in domestic ruminants in Ixodes ricinus-infested areas in northern Europe. In recent years, the bacterium has been found associated with Ixodes-tick species more or less worldwide on the northern hemisphere. A. phagocytophilum has a broad host range and may cause severe disease in several mammalian species, including humans. However, the clinical symptoms vary from subclinical to fatal conditions, and considerable underreporting of clinical incidents is suspected in both human and veterinary medicine. Several variants of A. phagocytophilum have been genetically characterized. Identification and stratification into phylogenetic subfamilies has been based on cell culturing, experimental infections, PCR, and sequencing techniques. However, few genome sequences have been completed so far, thus observations on biological, ecological, and pathological differences between genotypes of the bacterium, have yet to be elucidated by molecular and experimental infection studies. The natural transmission cycles of various A. phagocytophilum variants, the involvement of their respective hosts and vectors involved, in particular the zoonotic potential, have to be unraveled. A. phagocytophilum is able to persist between seasons of tick activity in several mammalian species and movement of hosts and infected ticks on migrating animals or birds may spread the bacterium. In the present review, we focus on the ecology and epidemiology of A. phagocytophilum, especially the role of wildlife in contribution to the spread and sustainability of the infection in domestic livestock and humans.
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Affiliation(s)
- Snorre Stuen
- Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science Sandnes, Norway.
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20
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Rejmanek D, Bradburd G, Foley J. Molecular characterization reveals distinct genospecies of Anaplasma phagocytophilum from diverse North American hosts. J Med Microbiol 2011; 61:204-212. [PMID: 21921109 DOI: 10.1099/jmm.0.034702-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Anaplasma phagocytophilum is an emerging tick-borne pathogen that infects humans, domestic animals and wildlife throughout the Holarctic. In the far-western United States, multiple rodent species have been implicated as natural reservoirs for A. phagocytophilum. However, the presence of multiple A. phagocytophilum strains has made it difficult to determine which reservoir hosts pose the greatest risk to humans and domestic animals. Here we characterized three genetic markers (23S-5S rRNA intergenic spacer, ank and groESL) from 73 real-time TaqMan PCR-positive A. phagocytophilum strains infecting multiple rodent and reptile species, as well as a dog and a horse, from California. Bayesian and maximum-likelihood phylogenetic analyses of all three genetic markers consistently identified two major clades, one of which consisted of A. phagocytophilum strains infecting woodrats and the other consisting of strains infecting sciurids (chipmunks and squirrels) as well as the dog and horse strains. In addition, analysis of the 23S-5S rRNA spacer region identified two unique and highly dissimilar clades of A. phagocytophilum strains infecting several lizard species. Our findings indicate that multiple unique strains of A. phagocytophilum with distinct host tropisms exist in California. Future epidemiological studies evaluating human and domestic animal risk should incorporate these distinctions.
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Affiliation(s)
- Daniel Rejmanek
- University of California, Davis School of Veterinary Medicine, Department of Medicine and Epidemiology, Davis, CA 95616, USA
| | - Gideon Bradburd
- University of California, Davis, Center for Population Biology, Department of Evolution and Ecology, Davis, CA 95616, USA
| | - Janet Foley
- University of California, Davis School of Veterinary Medicine, Department of Medicine and Epidemiology, Davis, CA 95616, USA
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