Studies on Tick Borne Diseases in Virginia
Confirmation of Borrelia burgdorferi sensu stricto and Anaplasma phagocytophilum in Ixodes scapularis, Southwestern Virginia
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Published in Volume: 14 Issue 11: November 19, 2014
Brian H. Herrin,1 Anne M. Zajac,2 and Susan E. Little1
1Veterinary Pathobiology, Oklahoma State University Center for Veterinary Health Sciences, Stillwater, Oklahoma.
2Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, Virginia.
Address correspondence to:
Susan E. LittleOklahoma State University
Department of Veterinary Pathobiology
Center for Veterinary Health Sciences
Stillwater, OK 74078E-mail: email@example.com
To determine the prevalence of Borrelia burgdorferi and Anaplasma phagocytophilum in a newly established population of Ixodes scapularis in the mountainous region of southwestern Virginia, questing adult ticks were collected and the identity and infection status of each tick was confirmed by PCR and sequencing. A total of 364 adult ticks were tested from three field sites.
B. burgdorferi sensu stricto was identified in a total of 32/101 (32%) ticks from site A, 49/154 (32%) ticks from site B, and 36/101 (36%) ticks from site C, for a total prevalence rate of 33% (117/356). In addition, A. phagocytophilum was detected in 3/364 (0.8%) ticks, one from site A and two from site B. The prevalence of both pathogens in ticks at these sites is similar to that reported from established endemic areas.
These data document the presence of I. scapularis and the agent of Lyme disease in a newly established area of the Appalachian region, providing further evidence of range expansion of both the tick and public and veterinary health risk it creates.
Vector-Borne and Zoonotic Diseases
Published in Volume: 11 Issue 11: November 11, 2011
In this study, chronic canine and human disease, for which causation was not diagnostically defined, were reported by the breeder of a kennel of Doberman pinschers. In addition to other diagnostic tests, serology, polymerase chain reaction, and enrichment blood culture were used to assess the prevalence of Bartonella sp. infection in the dogs and their owner.
From five dogs, Bartonella vinsonii subsp. berkhoffii genotype I, multiple Bartonella henselae strains, and a species most similar to Candidatus B. volans, a rodent-associated Bartonella sp., were amplified and sequenced from biopsy tissues, cerebrospinal fluid, or blood enrichment cultures.
The owner was bacteremic with B. vinsonii subsp. berkhoffii genotype I, the same subsp. and genotype detected in one of her dogs. These results further emphasize the ecological complexity of Bartonella sp. transmission in nature.
Vector Borne Zoonotic Dis. 2004 Fall;4(3):221-9.
The dog as a sentinel for human infection: prevalence of Borrelia burgdorferi C6 antibodies in dogs from southeastern and mid-Atlantic states.
Department of Clinical Sciences, North Carolina State University, College of Veterinary Medicine, Raleigh, North Carolina 27606, USA.
Lyme disease is the most frequently reported human vector-associated disease in the United States. Infection occurs after the bite of an Ixodid tick that is infected with Borrelia burgdorferi. Dogs have often been reported to serve as effective sentinel animals to assess the risk of human B. burgdorferi infection.
Based on published data of human Lyme disease case numbers and our clinical impressions, we hypothesized that canine exposure to B. burgdorferi would be lower in North Carolina when compared to the exposure in Virginia, Maryland, and Pennsylvania. To address this hypothesis, we evaluated B. burgdorferi exposure status utilizing a specific and sensitive C6 peptide-based enzyme-linked immunosorbent assay.
Our convenience sample included 1,666 canine serum samples submitted to the Vector Borne Disease Diagnostic Laboratory from North Carolina (n = 987), Virginia (n = 472), Maryland (n = 167), and Pennsylvania (n = 40).
Comparisons among states were made using the Chi-square test or the Fisher's exact test; p-values were adjusted for multiple comparisons using the Bonferroni correction. A Chi-square test for trend was used to determine if there was an increase in the frequency of seroreactors associated with the geographical origin of the samples.
The proportion of seroreactive dogs in North Carolina was markedly lower (p < 0.008) than that observed in dogs from Virginia, Maryland, and Pennsylvania.
These results support the hypothesis that B. burgdorferi transmission seems to occur infrequently in North Carolina dogs as compared to dogs residing in other southeastern and mid-Atlantic states.
Furthermore, they support the utility of dogs as a sentinel to characterize the risk of B. burgdorferi transmission to humans in a defined geographical location.
PMID: 15631067 [PubMed - indexed for MEDLINE]
Vector Borne Zoonotic Dis. 2005 Summer;5(2):101-9.
The dog as a sentinel for human infection: prevalence of Borrelia burgdorferi C6 antibodies in dogs from southeastern and mid-Atlantic States.
Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine (NCSU-CVM), Raleigh, North Carolina 27606, USA.
Lyme disease is the most frequently reported human vector-associated disease in the United States. Infection occurs after the bite of an Ixodid tick that is infected with Borrelia burgdorferi.
Dogs have often been reported to serve as effective sentinel animals to assess the risk of human B. burgdorferi infection.
Based on published data of human Lyme disease case numbers and our clinical impressions, we hypothesized that canine exposure to B. burgdorferi would be lower in North Carolina when compared to the exposure in Virginia, Maryland, and Pennsylvania.
To address this hypothesis, we evaluated B. burgdorferi exposure status utilizing a specific and sensitive C6 peptide-based enzyme-linked immunosorbent assay.
Our convenience sample included 1,666 canine serum samples submitted to the Vector-Borne Disease Diagnostic Laboratory from North Carolina (n = 987), Virginia (n = 472), Maryland (n = 167), and Pennsylvania (n = 40). Comparisons among states were made using the Chisquare test or the Fisher's exact test; p-values were adjusted for multiple comparisons using the Bonferroni correction.
A Chi-square test for trend was used to determine if there was an increase in the frequency of seroreactors associated with the geographical origin of the samples. The proportion of seroreactive dogs in North Carolina was markedly lower (p < 0.008) than that observed in dogs from Virginia, Maryland, and Pennsylvania.
These results support the hypothesis that B. burgdorferi transmission seems to occur infrequently in North Carolina dogs as compared to dogs residing in other southeastern and mid-Atlantic states. Furthermore, they support the utility of dogs as a sentinel to characterize the risk of B. burgdorferi transmission to humans in a defined geographical location.
PMID: 16011425 [PubMed - indexed for MEDLINE]
Clin Pediatr (Phila). 2005 Jun;44(5):419-21.
Division of Immunology and Rheumatology, Department of Pediatrics, University of Virginia Health System, Charlottesville, Virginia 22908, USA.
In non-endemic areas of the country, Lyme disease may not be considered in children who present with arthritis. This report details the clinical features of Lyme arthritis in 20 children residing in central Virginia.
All patients presented with transient, often recurrent oligoarthritis of large joints, particularly the knee. Most patients were referred with a presumptive diagnosis of juvenile rheumatoid arthritis (JRA).
This report reiterates the clinical presentation of Lyme arthritis in children and reminds physicians to consider the diagnosis of Lyme arthritis in children who present with acute arthritis even if they reside in a non-endemic area of the country.
In addition, it differentiates the clinical presentation of Lyme arthritis from JRA.
PMID: 15965548 [PubMed - indexed for MEDLINE]
Mil Med. 2003 Dec;168(12):1011-4.
Preventive Medicine Directorate, Navy Environmental Health Center, 620 John Paul Jones Circle, Portsmouth, VA 23708, USA.
Reported cases of Lyme disease for Navy and Marine Corps personnel during 1997-2000 are presented from data collected in the Naval Disease Reporting System and the Defense Medical Epidemiological Database.
Naval Disease Reporting System identified 210 case subjects; 60% were men, 49% were family members, and 37% were active duty, and most originated in the second quarter of the calendar year.
States reporting the greatest number of reports were Connecticut (44%), North Carolina (16%), Rhode Island (10%), and Virginia (10%), which was generally consistent with national figures and the concentration of military populations.
Incidence rates from Defense Medical Epidemiological Database for Lyme disease were generally higher for active duty personnel than reported civilian rates. Areas for improvement for Naval Disease Reporting System are identified and include additional emphasis on complete reporting on patient history and on Lyme disease antibody testing results.
These findings suggest that Lyme disease is an important disease in military medicine, particularly in the eastern United States.
PMID: 14719627 [PubMed - indexed for MEDLINE]
Adolesc Med. 2002 Oct;13(3):663-81.
Department of Psychiatric Medicine, University of Virginia Health System, Charlottesville, Virginia 22908-0203, USA.
This article discusses the neuropsychological sequelae of adolescent infectious diseases. Primary care physicians are encouraged to extend their clinical activities beyond the primary medical care aspects of the infectious disease process to encompass a comprehensive, multidisciplinary, continuum of health care approach.
Patient, disease, and socioecologic parameters are the foundation of this approach. This article is designed to help primary care physicians appreciate the complexity of neuropsychological infectious disease issues in the adolescent.
Human immunodeficiency virus 1 (HIV-1) is emphasized because the legion of related sequelae demands a comprehensive health care approach and serves as a model for discussing other principal infectious diseases such as encephalitis (particularly Lyme disease) and bacterial meningitis.
PMID: 12270806 [PubMed - indexed for MEDLINE]
Mil Med. 2001 Feb;166(2):191-3.
Naval Ambulatory Care Center, Internal Medicine, Newport, RI 02841, USA.
A case of human ehrlichiosis (caused by infection with Ehrlichia chaffeensis) is presented. The patient was a female Naval Academy midshipman with a 26-day history of daily field training with the U.S. Marines near Quantico, Virginia.
She presented with a several-day history of myalgias, fever, and frontal headache. During her clinical course, she developed fever to 104 degrees F, dry cough, dyspnea on exertion, arthralgias, and nephrotic syndrome.
She did not develop a rash. Laboratory studies were significant for thrombocytopenia, equivocal Lyme enzyme immunosorbent assay with a negative confirmatory western immunoblot, equivocal Rocky Mountain spotted fever acute serology without a convalescent increase in immunoglobulin G, and immunoglobulin G/immunoglobulin M serology positive for human monocytic ehrlichiosis.
She manifested known sequelae for this emerging disease, including dyspnea, pedal edema, increased transminases, and nephrotic syndrome.
PMID: 11272720 [PubMed - indexed for MEDLINE]
J Med Entomol. 1999 Sep;36(5):578-87.
Ticks and antibodies to Borrelia burgdorferi from mammals at Cape Hatteras, NC and Assateague Island, MD and VA.
Institute of Arthropodology & Parasitology, Georgia Southern University, Statesboro 30460, USA.
Results of a survey for ixodid ticks and/or serum antibodies to Borrelia burgdorferi from 14 species of small to large mammals from eastern coastal areas of the United States are presented.
Most samples were obtained from July 1987 through June 1989 (excluding December-March) at 3 locales: Assateague Is. National Seashore, Worcester Co., MD., and Accomack Co., VA. (approximately 38 degrees 05' N 75 degrees 10' W), and Cape Hatteras National Seashore, Dare Co., NC (approximately 35 degrees 30' N 76 degrees 35' W).
Hosts sampled included opossums (Didelphis virginiana), least shrews (Cryptotis parva), gray foxes (Urocyon cinereoargenteus), red foxes (Vulpes vulpes), raccoons (Procyon lotor), feral cats (Felis sylvestris), feral horses (Equus caballus), sika deer (Cervus nippon), rice rats (Oryzomys palustris), white-footed mice (Peromyscus leucopus), meadow voles (Microtus pennsylvanicus), house mice (Mus musculus), norway rats (Rattus norvegicus) and jumping mice (Zapus hudsonius).
An indirect fluorescent antibody test was used for testing sera from opossums, raccoons, and feral cats; enzyme-linked immunosorbent assays were used for sera from foxes, horses, deer, and house and white-footed mice.
Antibodies to B. burgdorferi were found in all species tested from each locale. Seasonal data reinforce the contention that P. leucopus is a suitable sentinel species for B. burgdorferi.
Ticks on hosts included Ixodes scapularis Say, I. texanus Banks, Dermacentor variabilis (Say), D. albipictus (Packard), and Amblyomma americanum (L.).
Males comprised approximately 0-22 and 60-81% of Ixodes sp. and Amblyomma-Dermacentor adults collected from hosts, respectively.
All stages of A. americanum, adult D. variabilis, and larval I. scapularis were collected from vegetation.
The highest seropositivity rate (67%) was recorded for 45 P. leucopus at Assateague during July, approximately 1 mo. after peak nymphal I. scapularis intensity. Borrelia burgdorferi was isolated from 6 nymphal and 12 female I. scapularis collected from P. leucopus and C. nippon, respectively, on Assateague.
PMID: 10534951 [PubMed - indexed for MEDLINE]
J Med Entomol. 1998 Sep;35(5):629-38.
Reported distribution of Ixodes scapularis and Ixodes pacificus (Acari: Ixodidae) in the United States.
Division of Vector-Borne Infection Diseases, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Fort Collins, CO 80522, USA.
Lyme disease, caused by infection with Borrelia burgdorferi, is the most frequently reported arthropod-borne disease in the United States. To develop a national map of the distribution of the vectors of B. burgdorferi to humans (Ixodes scapularis Say and Ixodes pacificus Cooley & Kohls ticks), we sent questionnaires to acarologists, health officials, and Lyme disease researchers; surveyed the 1966-1996 MEDLINE data base; and reviewed 1907-1995 National Tick Collection data.
Tick collection methods cited included flagging and dragging, deer surveys, small- and medium-sized mammal surveys, CO2 baiting, and receipt of tick submissions. A total of 1,058 unique, county-specific I. scapularis and I. pacificus records was obtained.
Tick populations were classified as "reported" (< 6 ticks and 1 life stage identified) or "established" (> or = 6 ticks or > 1 life stage identified). Established populations of I. scapularis were identified in 396 counties in 32 states in the eastern and central United States, whereas established populations of I. pacificus were found in 90 counties in 5 western states.
Counties with established populations were most concentrated in the northeastern, upper northcentral, and west-coastal states but were also clustered in southeastern and Gulf-coastal states.
A less concentrated distribution was found in the south-central states. Reports were notably missing from all but a few counties in Ohio, West Virginia, western Virginia and North Carolina, Kentucky, and Tennessee.
They were absent in the Great Plains and Rocky Mountain regions and from large areas of western states east of the Cascade and Sierra Nevada cordilleras. These data are useful for identifying areas of Lyme disease risk, for targeting Lyme disease prevention strategies, and for monitoring trends in spatial distribution of Lyme disease vector ticks.
PMID: 9775584 [PubMed - indexed for MEDLINE]
J Med Entomol. 1998 Jan;35(1):54-8.
New York State Department of Health, SUNY College of Environmental Science and Forestry, Syracuse 13210, USA.
A 918-km section of the Appalachian National Scenic Trail from the West Virginia-Maryland border to the Massachusetts-Vermont border was surveyed for the presence of Ixodes scapularis Say.
The trail and its edges were drag-sampled during 4 hikes between May and October 1991. Trips were designed to survey areas of the Appalachian Trail when I. scapularis might be questing and to revisit states endemic for Lyme disease during differing times.
After sampling for ticks, meteorological and ecological characteristics were measured at each site. In total, 1,776 km of the Appalachian Trail were hiked during 88 d and resulted in sampling 489 sites. All life stages of Ixodes scapularis (n = 46) were collected from 21 sites within a 331-km range of the Appalachian Trail between Salisbury, CT, to Delaware Water Gap, PA.
This segment of Appalachian Trial is easily accessible to a large urban population and should be posted with tick warning signs to alert the public to the presence of I. scapularis.
PMID: 9542345 [PubMed - indexed for MEDLINE]
Am J Trop Med Hyg. 1995 Aug;53(2):123-33.
Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA.
In Virginia, Borrelia burgdorferi was more prevalent in a site along the Atlantic Ocean, near Maryland, than in an inland site near Williamsburg and Yorktown.
At the coastal site on Assateague Island, B. burgdorferi was isolated from 4.2% of 475 animals sampled, including four species of small mammals. Serologic tests indicated that 25-37% of the small rodents assayed had been exposed to B. burgdorferi. Immunofluorescence antibody assays specific for B. burgdorferi showed spirochete infection in Ixodes scapularis and Dermacentor variabilis but not in other species of ticks also examined from this site.
At another coastal site (Parramore Island), no evidence of Peromyscus leucopus was found, no immature specimens of I. scapularis were collected, and no isolations were made from numerous raccoons or small mammals sampled. Borrelia burgdorferi infection was found in one I. cookei nymph, but not in numerous specimens of I. scapularis or other tick species from this locality.
At the inland site between Williamsburg and Yorktown, B. burgdorferi was isolated from two small mammal species and antibodies to B. burgdorferi were found in only 7-10% of the small mammals sampled. Ixodes scapularis were less abundant at this locality than at the Assateague Island site.
Borrelia burgdorferi spirochetes were found in I. scapularis and a single nymph of Amblyomma americanum, but not in any of numerous specimens of four other species. Infection with B. burgdorferi was found in 20% of unfed adult I. scapularis from vegetation, but in only 0.2% of numerous adults from hunter-killed deer.
Infection in immature ticks was much lower than at Assateague Island. Borrelia burgdorferi may be more prevalent along the Atlantic coast than in inland areas.
Isolations, seroprevalence, immature I. scapularis densities, and spirochete infection rates in ticks were higher at the Assateague Island site than the Williamsburg/Yorktown site.
Consequently, the risk of human exposure to Lyme disease may be higher in some parts of the coastal area than elsewhere in Virginia. Overall, B. burgdorferi is less intense in Virginia than in the northeastern United States.
PMID: 7677212 [PubMed - indexed for MEDLINE]
Am J Med Sci. 1990 Nov;300(5):283-7.
Division of Infectious Diseases, Medical College of Virginia, Virginia Commonwealth University, Richmond.
Prior to January 1986, only one case of Lyme disease was reported from Virginia. In 1986-87, however, the Virginia Department of Health observed an increase in reports of suspected Lyme disease by physicians, despite the fact that Ixodes dammini is not highly prevalent in the Virginia tick population.
Twenty-eight cases of Lyme disease were identified in Virginia, of which eight cases occurred in 1986 and 20 in 1987. Lyme disease appears to be increasing in frequency in Virginia and moving southward along the Eastern Atlantic Seaboard.
PMID: 2240015 [PubMed - indexed for MEDLINE]
J Rheumatol. 1990 Sep;17(9):1193-4.
Department of Pediatrics, University of Virginia Health Sciences Center, Charlottesville.
Lyme arthritis and juvenile rheumatoid arthritis (JRA) share a number of clinical features. Our study was performed in order to determine the prevalence of antibody to Borrelia burgdorferi in 50 children with JRA who reside in a nonendemic area.
Three patients were weakly reactive and one patient was reactive when tested using an enzyme immunoassay to detect serum antibody to B. burgdorferi.
No patient, however, had definitive serologic evidence of B. burgdorferi infection by Western blot analysis. We conclude that the prevalence of antibody to B. burgdorferi is very low in children with JRA who reside in a nonendemic area.
PMID: 2290160 [PubMed - indexed for MEDLINE]
J Med Entomol. 1990 Jul;27(4):671-80.
Computer simulation of Rocky Mountain spotted fever transmission by the American dog tick (Acari: Ixodidae).
Insects Affecting Man and Animals Research Laboratory, USDA-ARS, Gainesville, Florida 32604.
A computer model was developed for simulation of the transmission of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever (RMSF), by the American dog tick, Dermacentor variabilis (Say).
The model of RMSF was combined with a model for population dynamics of the American dog tick and included simulation of infection and transmission of rickettsiae between ticks and host mammals and transmission of RMSF to humans.
The model simulated the effects of biotic and environmental variables such as weather, host density, habitat, transovarial transmission, fecundity of infected ticks, and infectivity level of ticks and mammals.
Some parameters in the model were fitted by iterative simulations to produce realistic rates of R. rickettsii infection in adult ticks and small and medium-sized mammal hosts. Parameters also were fitted to yield the historical average number of RMSF cases for Virginia.
Comparisons of the simulated and actual number of cases for nine other states indicated a reasonable level of validity for the model.
A theoretical tick density threshold of 252 unfed adult ticks/ha for transmission of RMSF was determined from a relationship between rate of transmission to humans and density of ticks.
The transmission threshold can be used for additional modeling efforts to study the effects of management technologies on tick densities and RMSF human cases. The model can serve as a framework for modeling other tick-borne diseases such as Lyme disease, babesiosis, and heartwater.
PMID: 2388242 [PubMed - indexed for MEDLINE]
Mo Med. 1990 Feb;87(2):86-8.
Department of Medicine, Medical College of Virginia, Virginia Commonwealth University, Richmond.
Lyme disease in most cases occurs in the states of Connecticut, Wisconsin, Oregon, California, Missouri and parts of the northeastern coast. Showing the exception to the rule, the authors discuss a case in which a patient acquired the disease on the Eastern Shore of Virginia.
PMID: 2304446 [PubMed - indexed for MEDLINE]
Am Fam Physician. 1988 Jun;37(6):95-104.
University of Virginia School of Medicine, Charlottesville.
Tick-borne diseases have their peak incidence in the spring and summer. The different infections caused by tick vectors have certain geographic locations and unique clinical presentations. The most common tick-transmitted infection is Lyme disease. Early diagnosis of tick-borne disease is essential so that effective and, in some cases, lifesaving antibiotic therapy can be instituted. Preventive measures are simple.
PMID: 3289344 [PubMed - indexed for MEDLINE]