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Foley J, López-Pérez AM, Rubino F, Backus L, Ferradas C, Barrón-Rodriguez J, Mendoza H, Arroyo-Machado R, Inustroza-Sánchez LC, Zazueta OE. Roaming Dogs, Intense Brown Dog Tick Infestation, and Emerging Rocky Mountain Spotted Fever in Tijuana, México. Am J Trop Med Hyg 2024; 110:779-794. [PMID: 38377609 PMCID: PMC10993825 DOI: 10.4269/ajtmh.23-0410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/30/2023] [Indexed: 02/22/2024] Open
Abstract
A two decades-long epidemic of Rocky Mountain spotted fever in northern México reached the U.S. border city of Tijuana in 2021. Cases were near the city periphery in marginalized areas, some lacking infrastructure such as streets or utilities. We worked in the three census areas where human cases were reported and in 12 additional control Áreas Geoestadisticas Básicas. There were dogs, the primary tick host and Rickettsia rickettsii reservoir, in 76% of homes, with 2.2 owned dogs per home on average, approximately equal numbers of roaming dogs were seen, and 46.2% of owned dogs were allowed to roam in the street. Sixty-eight percent of people had heard of Rocky Mountain spotted fever (RMSF), and 35% self-reported tick infestation, including 19% of homes without dogs. Ticks appeared to move among houses of adjacent neighbors. Of 191 examined dogs, 61.8% were tick-infested, with 6-fold increased odds if they were allowed to roam. Although no dogs were Rickettsia polymerase chain reaction-positive, we found one R. rickettsii- and 11 Rickettsia massiliae-infected ticks. The rickettsial IgG seroprevalence by immunofluorescence antibody assay was 76.4%, associated with unhealthy body condition, adults, dogs with >10 ticks, more dogs being seen in the area, and dogs being permitted in the street. Insufficient medical and canine management resources have contributed to a case fatality rate of RMSF that has exceeded 50% in areas. High canine seroprevalence suggests risks to people and dogs; unfortunately, herd immunity is impeded by high turnover in the canine population owing to the birth of puppies and high death rates. Binational One Health workers should monitor disease spread, enact canine population management and tick eradication, and provide prevention, diagnostic, and treatment support.
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Affiliation(s)
- Janet Foley
- School of Veterinary Medicine, University of California, Davis, California
| | - Andrés M. López-Pérez
- School of Veterinary Medicine, University of California, Davis, California
- Red de Biología y Conservación de Vertebrados, Instituto de Ecología, Xalapa, México
| | - Francesca Rubino
- School of Veterinary Medicine, University of California, Davis, California
| | - Laura Backus
- School of Veterinary Medicine, University of California, Davis, California
| | - Cusi Ferradas
- School of Veterinary Medicine, University of California, Davis, California
- Emerge, Unidad de Investigación en Enfermedades Emergentes y Cambio Climático, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Julio Barrón-Rodriguez
- Departamento de Ecología, Fauna Silvestre y Animales de Laboratorio, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, México City, México
| | - Hugo Mendoza
- Departamento de Ecología, Fauna Silvestre y Animales de Laboratorio, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, México City, México
| | | | | | - Oscar E. Zazueta
- Departamento de Epidemiología, Secretaría de Salud de Baja California, Mexicali, México
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McCarthy ML, Wallace DI. Optimal control of a tick population with a view to control of Rocky Mountain Spotted Fever. Math Biosci Eng 2023; 20:18916-18938. [PMID: 38052583 DOI: 10.3934/mbe.2023837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
In some regions of the Americas, domestic dogs are the host for the tick vector Rhipicephalus sanguineus, and spread the tick-borne pathogen Rickettsia rickettsii, which causes Rocky Mountain Spotted Fever (RMSF) in humans. Interventions are carried out against the vector via dog collars and acaricidal wall treatments. This paper investigates the optimal control of acaricidal wall treatments, using a prior model for populations and disease transmission developed for this particular vector, host, and pathogen. It is modified with a death term during questing stages reflecting the cost of control and level of coverage. In the presence of the control, the percentage of dogs and ticks infected with Ri. rickettsii decreases in a short period and remains suppressed for a longer period, including after treatment is discontinued. Risk of RMSF infection declines by 90% during this time. In the absence of re-application, infected tick and dog populations rebound, indicating the eventual need for repeated treatment.
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Affiliation(s)
- Maeve L McCarthy
- Department of Mathematics & Statistics, Murray State University, 203A Industry & Technology, Murray KY 42071, USA
| | - Dorothy I Wallace
- Department of Mathematics, Dartmouth College, 27 N. Main Street, 6188 Kemeny Hall, Hanover, NH 03755-3551, USA
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Marcek J, Foley J, Backus L, Suzan G, López-Pérez AM. POTENTIAL SHARED DISEASE RISK AMONG DOGS AND COYOTES (CANIS LATRANS) EXEMPLIFIED BY THE ECOLOGY OF RICKETTSIOSIS IN A ROCKY MOUNTAIN SPOTTED FEVER-EPIDEMIC REGION IN NORTHERN MEXICO. J Wildl Dis 2023; 59:722-733. [PMID: 37846906 DOI: 10.7589/jwd-d-22-00179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 03/31/2023] [Indexed: 10/18/2023]
Abstract
Rocky Mountain spotted fever (RMSF), caused by the bacterium Rickettsia rickettsii, is a re-emerging tick-borne zoonosis in North America, with hundreds of human fatalities in multiple outbreaks in northern Mexico and the southwestern US in the past few decades. Free-roaming dogs are key because they are reservoirs for the pathogen and the main hosts of the brown dog tick (Rhipicephalus sanguineus), which vectors RMSF in this region. Because coyotes (Canis latrans) can be infected with R. rickettsii and infested with Rh. sanguineus, we hypothesized that space sharing among dogs and coyotes could enhance disease risks. In summer 2021, we captured and sampled 11 coyotes at two sites in Baja California, Mexico, near population centers with human cases of RMSF, and fitted seven individuals with GPS logging collars. We also tested tissue samples, sera, and ectoparasites for DNA of R. rickettsii with PCR and used serology to detect antibodies to R. rickettsii. Finally, we deployed an array of cameras to document dog-coyote interactions. Mean home range size was 40.37 km2. Both GPS and camera data showed considerable home range overlap both between individual coyotes and between coyotes and dogs. Coyotes were active in areas where dogs occur including the domestic interface surrounding human settlements. Although none of our samples were positive for R. rickettsii on PCR, 72.7% (8/11) of the samples were seropositive with titers ≥64. Our data confirm shared space use and risk of shared parasites and disease between coyotes and dogs.
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Affiliation(s)
- Jacob Marcek
- University of California-Davis, School of Veterinary Medicine, Department of Medicine and Epidemiology, 1275 Med Science Dr., Davis, California 95616, USA
| | - Janet Foley
- University of California-Davis, School of Veterinary Medicine, Department of Medicine and Epidemiology, 1275 Med Science Dr., Davis, California 95616, USA
| | - Laura Backus
- University of California-Davis, School of Veterinary Medicine, Department of Medicine and Epidemiology, 1275 Med Science Dr., Davis, California 95616, USA
| | - Gerardo Suzan
- Laboratorio de Ecología de Enfermedades y Una Salud, Departamento de Etología, Fauna Silvestre y Animales de Laboratorio, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Ciudad Universitaria, Av. Universidad no. 3000, Coyoacán 04510 Ciudad de México, Mexico
| | - Andrés M López-Pérez
- University of California-Davis, School of Veterinary Medicine, Department of Medicine and Epidemiology, 1275 Med Science Dr., Davis, California 95616, USA
- Red de Biología y Conservación de Vertebrados, Instituto de Ecología, A.C., Carretera antigua a Coatepec 351, El Haya, Xalapa, Veracruz 91073, Mexico
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Muniz APM, Tolesano-Pascoli G, Vieira RBK, Polli MG, Rodrigues VDS, Gonzaga HT, Mamede CCN, Da Cunha NC, Szabó MJP, Yokosawa J. Evaluation of a mimotope of the Rickettsia outer membrane protein A (OmpA) as an antigen in enzyme-linked immunosorbent assay to detect rickettsiosis in capybaras (Hydrochoerus hydrochaeris), horses (Equus caballus), and opossums (Didelphis sp.). Exp Appl Acarol 2023; 89:317-327. [PMID: 36795267 DOI: 10.1007/s10493-023-00776-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Rickettsia rickettsii is the etiological agent of Rocky Mountain spotted fever, which is an important tick-borne zoonosis and, in Brazil, it causes Brazilian spotted fever, which has high lethality rate. This study aimed to evaluate a synthetic peptide corresponding to a segment of the outer membrane protein A (OmpA) as an antigen in a serological test for the diagnosis of rickettsial infections. The amino acid sequence of the peptide was selected by predicting B cell epitopes using B Cell Epitope Prediction (Immune Epitope Database and Analysis Resource) and Epitopia and OmpA sequences of Rickettsia rickettsii strain 'Brazil' and Rickettsia parkeri strains 'Maculatum 20' and 'Portsmouth'. A peptide with amino acid sequence common to both Rickettsia species was synthesized and arbitrarily named OmpA-pLMC. To evaluate this peptide in enzyme-linked immunosorbent assay (ELISA), serum samples of capybara (Hydrochoerus hydrochaeris), horse (Equus caballus), and opossum (Didelphis albiventris) that had been previously tested by indirect immunofluorescence assay (IFA) for rickettsial infection were separated into IFA-positive and IFA-negative groups and used in the assay. There were no significant differences in ELISA optical density (OD) values between IFA-positive and IFA-negative groups with horse samples. The mean OD values were significantly higher in the IFA-positive capybara serum samples (IFA-pos vs. IFA-neg = 2.389 ± 0.761 vs. 1.760 ± 0.840). However, receiver operating characteristic (ROC) curve analysis did not show significant diagnostic parameters. On the other hand, 12 out of 14 (85.7%) opossum samples of the IFA-positive group showed reactivity in ELISA, and this was significantly higher than of the IFA-negative group (0.7196 ± 0.440 vs. 0.2318 ± 0.098, respectively; 85.7% sensitivity, 100% specificity). Therefore, our results show that OmpA-pLMC has a potential to be used in immunodiagnostic assays to detect spotted fever group rickettsial infections.
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Affiliation(s)
- Ana Paula Mendes Muniz
- Laboratory of Microorganisms of Cerrado (Brazilian Savannah), Department of Microbiology, Instituto De Ciências Biomédicas (ICBIM), Universidade Federal de Uberlândia (UFU), Uberlândia, Brazil
| | | | - Raíssa Brauner Kamla Vieira
- Laboratory of Ixodology, Faculdade de Medicina Veterinária, UFU, Uberlândia, Brazil
- Department of Veterinary Public Health, Universidade Federal Fluminense (UFF), Niterói, Brazil
| | - Mayara Garcia Polli
- Laboratory of Microorganisms of Cerrado (Brazilian Savannah), Department of Microbiology, Instituto De Ciências Biomédicas (ICBIM), Universidade Federal de Uberlândia (UFU), Uberlândia, Brazil
| | | | | | | | - Nathalie Costa Da Cunha
- Department of Veterinary Public Health, Universidade Federal Fluminense (UFF), Niterói, Brazil
| | | | - Jonny Yokosawa
- Laboratory of Microorganisms of Cerrado (Brazilian Savannah), Department of Microbiology, Instituto De Ciências Biomédicas (ICBIM), Universidade Federal de Uberlândia (UFU), Uberlândia, Brazil.
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Backus L, Foley J, Chung C, Virata S, Zazueta OE, López-Pérez A. Tick-borne pathogens detected in sheltered dogs during an epidemic of Rocky Mountain spotted fever, a One Health challenge. J Am Vet Med Assoc 2022; 261:375-383. [PMID: 36563069 DOI: 10.2460/javma.22.08.0388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To assess exposure to and infection with 3 pathogens (Rickettsia rickettsii, Anaplasma platys, and Ehrlichia canis) vectored by brown dog ticks (Rhipicephalus sanguineus) in sheltered dogs at the western US-Mexico border. ANIMALS 239 dogs in shelters in San Diego and Imperial counties, US, and Mexicali and Tijuana, Mexico. PROCEDURES Each dog had blood drawn and basic demographic data collected. PCR was performed to determine active infection with Rickettsia spp, E canis, and A platys. Serology was performed to determine exposure to Rickettsia, Anaplasma, and Ehrlichia species. RESULTS 2 of 78 (2.6%) dogs sampled in Tijuana were actively infected with R rickettsii. A single brown dog tick collected from a dog in Tijuana was PCR-positive for R rickettsii. Infection with E canis and A platys ranged across shelters from 0% to 27% and 0% to 33%, respectively. Dogs in all 4 locations demonstrated exposure to all 3 pathogens, though Rickettsia and Ehrlichia seropositivity was highest in Mexicali (81% and 49%, respectively) and Anaplasma seropositivity was highest in Tijuana (45%). CLINICAL RELEVANCE While infection and exposure were highest in sheltered dogs in the southern locations, dogs in all locations demonstrated exposure to all pathogens, demonstrating the potential for emergence and spread of zoonotic pathogens with significant public health consequences in southern California and northern Baja California. In addition, veterinarians and shelter staff should be aware that Ehrlichia or Anaplasma infection may co-occur with Rocky Mountain spotted fever, which is a human health risk.
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Affiliation(s)
- Laura Backus
- 1Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA
| | - Janet Foley
- 1Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA
| | - Claire Chung
- 1Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA
| | - Sophia Virata
- 1Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA
| | - Oscar E Zazueta
- 2Departamento Estatal de Epidemiología, Instituto de Servicios de Salud Pública del Estado de Baja California, Mexicali, México
| | - Andrés López-Pérez
- 1Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA
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Binder LDC, Ramírez-Hernández A, Serpa MCDA, Pinter A, Souza CE, Labruna MB. Long-term persistence of anti-Rickettsia rickettsii antibodies in capybaras, with passive transfer to offspring. Rev Bras Parasitol Vet 2022; 31:e009922. [PMID: 36169507 DOI: 10.1590/s1984-29612022052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Abstract
The bacterium Rickettsia rickettsii is the etiological agent of Brazilian spotted fever (BSF), and its most important vector to humans in Brazil is the tick Amblyomma sculptum. Capybaras are the main hosts of A. sculptum in many BSF-endemic areas and are considered valuable sentinels for BSF surveillance. This study aimed to assess the persistence of anti-R. rickettsii antibodies for long periods in capybaras and their passive transfer to offspring. For this purpose, three adult capybaras previously exposed to multiple infections with R. rickettsii were followed up until 3.1 years after their last exposure. During the study, one female delivered five cubs, of which three survived. Blood samples were collected monthly from adults and infants, and serum samples were titrated by indirect immunofluorescence assay (IFA) to determine endpoint titers of anti-R. rickettsii antibodies. All three adults remained seroreactive to R. rickettsii with high endpoint titers until the end of the study. All infants were seroreactive to R. rickettsii after birth and remained seroreactive for one to four months. This study showed that exposure of capybaras to R. rickettsii-infected A. sculptum ticks elicits a persistent antibody response. In addition, there was evidence of passive transfer of R. rickettsii-reactive antibodies to offspring.
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Affiliation(s)
- Lina de Campos Binder
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo - USP, São Paulo, SP, Brasil
| | - Alejandro Ramírez-Hernández
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo - USP, São Paulo, SP, Brasil
- Grupo Parasitología Veterinaria, Universidad Nacional de Colombia, Bogotá D.C., Colombia
| | - Maria Carolina de Azevedo Serpa
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo - USP, São Paulo, SP, Brasil
| | | | - Celso Eduardo Souza
- Grupo de Vigilância Epidemiológica, Coordenadoria Controle de Doenças, Secretaria de Estado da Saúde, Campinas, SP, Brasil
| | - Marcelo Bahia Labruna
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo - USP, São Paulo, SP, Brasil
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Ribeiro CM, Carvalho JLBD, Bastos PADS, Katagiri S, Batalha EY, Okano W, Costa VMD. Prevalence of Rickettsia rickettsii in Ticks: Systematic Review and Meta-Analysis. Vector Borne Zoonotic Dis 2021; 21:557-565. [PMID: 34010063 DOI: 10.1089/vbz.2021.0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023] Open
Abstract
Background and Objectives:Rickettsia rickettsii is a pathogen that is known to cause spotted fever, a zoonosis that is endemic in several regions of the Americas. However, no systematic review and meta-analysis has been conducted to estimate the prevalence of this rickettsial disease in the Americas. Therefore, the objective of this study was to estimate the prevalence of R. rickettsii in ticks in the Americas. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed and data were retrieved from four electronic databases: MEDLINE/PubMed, SciELO, ScienceDirect, and Directory of Open Access Journals. The pooled prevalence and heterogeneity were determined using a random-effects model and using Cochran's Q test and I2 index, respectively. Publication bias was assessed using a funnel plot and Egger's method. Results: The pooled prevalence of R. rickettsii in ticks was highest in Colombia (17.00%; confidence interval [95% CI]: 7.01-30.24), followed by Mexico (9.89%; 95% CI: 2.03-22.74), Panama (2.76%; 95% CI: 0.45-6.93), Brazil (2.03%; 95% CI: 0.66-4.14), and the United States (0.50%; 95% CI: 0.15-1.05). The tick species most frequently infected by R. rickettsii were Rhipicephalus sanguineus sensu lato (6.23%; 95% CI: 2.79-10.92) and Amblyomma mixtum (4.36%; 95% CI: 0.25-13.14). Interpretation and Conclusion: It can be suggested that studies aiming to identify the potential vectors of R. rickettsii should be conducted more intensively to better understand the epidemiology of spotted fever in the Americas.
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Affiliation(s)
| | | | | | - Satie Katagiri
- Universidade Federal de Mato Grosso, Mato Grosso, Brazil
| | | | - Werner Okano
- Instituto de Tecnologia e Desenvolvimento Econômico e Social, Paraná, Brazil
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López-Pérez AM, Orozco L, Zazueta OE, Fierro M, Gomez P, Foley J. An exploratory analysis of demography and movement patterns of dogs: New insights in the ecology of endemic Rocky Mountain-Spotted Fever in Mexicali, Mexico. PLoS One 2020; 15:e0233567. [PMID: 32437470 PMCID: PMC7241830 DOI: 10.1371/journal.pone.0233567] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 05/07/2020] [Indexed: 12/13/2022] Open
Abstract
An outbreak of Rocky Mountain spotted fever (RMSF) transmitted by the brown dog tick (Rhipicephalus sanguineus sensu lato) has emerged as a major human and animal health concern in Mexicali, Mexico. Due to high rates of brown dog tick infestation, susceptibility, and association with humans, dogs serve as sentinels and have a key role in the ecology of RMSF. A cross-sectional household questionnaire study was conducted in six rural and urban locations to characterize dog ecology and demography in RMSF high-and low-risk areas of Mexicali. In addition, we tracked movement patterns of 16 dogs using a GPS data logger. Of 253 households, 73% owned dogs, and dog ownership tended to be higher in high-risk areas, with a mean dog:human ratio of 0.43, compared with 0.3 in low-risk areas. Dogs in high-risk areas had higher fecundity and roamed more, but the dog density and numbers of free-roaming dogs were comparable. There was a higher proportion of younger dogs and lower proportion of older dogs in high-risk areas. The high proportion of immunologically naïve puppies in high risk areas could result in a lack of herd immunity leading to a more vulnerable dog and human population. The marked increase of space use of free-roaming dogs in high-risk areas suggests that unrestrained dogs could play an important role in spreading ticks and pathogens. As means to limit RMSF risk, practical changes could include increased efforts for spay-neuter and policies encouraging dog restraint to limit canine roaming and spread of ticks across communities; due to dog density is less impactful such policies may be more useful than restrictions on the number of owned dogs.
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Affiliation(s)
- Andrés M. López-Pérez
- School of Veterinary Medicine, University of California, Davis, California, United States of America
- * E-mail:
| | - Libertad Orozco
- Área de Investigación en Biología de la Conservación, Departamento de Ciencias Ambientales, Universidad Autónoma Metropolitana-Lerma, Lerma de Villada, Estado de Mexico, Mexico
| | - Oscar E. Zazueta
- Secretaria de Salud Pública del Estado de Baja California, Mexicali, Mexico
| | - Maria Fierro
- Public Health Department, Imperial County, El Centro, California, United States of America
| | - Paola Gomez
- Secretaria de Salud Pública del Estado de Baja California, Mexicali, Mexico
| | - Janet Foley
- School of Veterinary Medicine, University of California, Davis, California, United States of America
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Costa FB, Gerardi M, Binder LDC, Benatti HR, Serpa MCDA, Lopes B, Luz HR, Ferraz KMPMB, Labruna MB. Rickettsia rickettsii (Rickettsiales: Rickettsiaceae) Infecting Amblyomma sculptum (Acari: Ixodidae) Ticks and Capybaras in a Brazilian Spotted Fever-Endemic Area of Brazil. J Med Entomol 2020; 57:308-311. [PMID: 31504641 DOI: 10.1093/jme/tjz141] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Indexed: 06/10/2023]
Abstract
The bacterium Rickettsia rickettsii is the agent of Brazilian spotted fever (BSF), a highly fatal disease that is transmitted in Brazil mainly by the tick Amblyomma sculptum Berlese, which uses capybaras (Hydrochoerus hydrochaeris Linnaeus) as major hosts. In 2015, we captured nine capybaras in a BSF-endemic area of southeastern Brazil. From each capybara, we collected blood sera that were tested through the immunofluorescence assay using Rickettsia spp. antigens, and A. sculptum ticks, processed for isolation of R. rickettsii through guinea pig inoculation. All capybaras (100%) were seroreactive to Rickettsia spp., with highest titers to R. rickettsii. A total of 166 A. sculptum ticks were macerated and inoculated into nine guinea pigs, from which only one presented high fever and seroconverted to R. rickettsii. Blood from this febrile animal was inoculated into additional guinea pigs (guinea pig passages), which also became febrile and seroconverted, or when euthanized during the fever period, their internal organs (spleen, lung) were shown to contain R. rickettsii DNA. The present rickettsial isolate has been maintained cryopreserved as infected guinea pig organs. There was at least one R. rickettsii-infected tick among the 166 macerated ticks, giving a minimal infection rate of 0.6% (1/166). This infection rate is within the range of previous studies, which reported that only 0.05% to at most 1.28% A. sculptum ticks were infected by R. rickettsii in other BSF-endemic areas. These low infection rates support the low incidence of BSF, despite of A. sculptum being the most frequent human-biting tick in southeastern Brazil.
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Affiliation(s)
- Francisco B Costa
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil
- Departamento de Patologia, Programa de Pós-graduação em Ciência Animal, Universidade Estadual do Maranhão, São Luís, MA, Brazil
| | - Monize Gerardi
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Lina de C Binder
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Hector R Benatti
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Maria Carolina de Azevedo Serpa
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Beatriz Lopes
- Departamento de Ciências Florestais, Universidade de São Paulo, Escola Superior de Agricultura 'Luiz de Queiroz', Piracicaba, SP, Brazil
| | - Hermes R Luz
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil
- Departamento de Patologia, Programa de Pós-Graduação em Biotecnologia do RENORBIO, Ponto Focal Maranhão, Universidade Federal do Maranhão, São Luís, MA, Brazil
| | - Katia M P M B Ferraz
- Departamento de Ciências Florestais, Universidade de São Paulo, Escola Superior de Agricultura 'Luiz de Queiroz', Piracicaba, SP, Brazil
| | - Marcelo B Labruna
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil
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Polo G, Mera Acosta C, Labruna MB, Ferreira F. Transmission dynamics and control of Rickettsia rickettsii in populations of Hydrochoerus hydrochaeris and Amblyomma sculptum. PLoS Negl Trop Dis 2017; 11:e0005613. [PMID: 28582429 PMCID: PMC5472331 DOI: 10.1371/journal.pntd.0005613] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 06/15/2017] [Accepted: 04/28/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Brazilian Spotted Fever (BSF), caused by the bacterium Rickettsia rickettsii, is the tick-borne disease that generates the largest number of human deaths in the world. In Brazil, the current increase of BSF human cases has been associated with the presence and expansion of capybaras Hydrochoerus hydrochaeris, which act as primary hosts for the tick Amblyomma sculptum, vector of the R. rickettsii in this area. METHODS We proposed a semi-discrete-time stochastic model to evaluate the role of capybaras in the transmission dynamics of R. rickettsii. Through a sensitivity analysis, we identified the parameters with significant influence on the R. rickettsii establishment. Afterward, we implemented the Gillespie's algorithm to simulate the impact of potential public health interventions to prevent BSF human cases. RESULTS The introduction of a single infected capybara with at least one infected attached tick is enough to trigger the disease in a non-endemic area. We found that to avoid the formation of new BSF-endemic areas, it is crucial to impede the emigration of capybaras from endemic areas by reducing their birth rate by more than 58%. Model results were corroborated by ex-situ data generated from field studies, and this supports our proposal to prevent BSF human cases by implementing control strategies focused on capybaras. CONCLUSION The proposed stochastic model illustrates how strategies for the control and prevention of vector-borne infectious diseases can be focused on amplifier hosts management practices. This work provides a basis for future prevention strategies for other neglected vector-borne diseases.
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Affiliation(s)
- Gina Polo
- Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine, University of São Paulo, São Paulo, SP, Brazil
| | | | - Marcelo B. Labruna
- Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine, University of São Paulo, São Paulo, SP, Brazil
| | - Fernando Ferreira
- Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine, University of São Paulo, São Paulo, SP, Brazil
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Peniche-Lara G, Jimenez-Delgadillo B, Dzul-Rosado K. Rickettsia rickettsii and Rickettsia felis infection in Rhipicephalus sanguineus ticks and Ctenocephalides felis fleas co-existing in a small city in Yucatan, Mexico. J Vector Ecol 2015; 40:422-424. [PMID: 26611982 DOI: 10.1111/jvec.12185] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Gaspar Peniche-Lara
- Facultad de Medicina, Unidad Interinstitucional de Investigación Clínica y Epidemiológica, Universidad Autónoma de Yucatán, Mérida Yucatán, México.
| | - Bertha Jimenez-Delgadillo
- Facultad de Medicina, Unidad Interinstitucional de Investigación Clínica y Epidemiológica, Universidad Autónoma de Yucatán, Mérida Yucatán, México
| | - Karla Dzul-Rosado
- Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, México, Avenida Itzaés # 490 × Calle 59 Colonia Centro C.P, 97000 Mérida, Yucatán, México
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Pacheco RC, Moraes-Filho J, Guedes E, Silveira I, Richtzenhain LJ, Leite RC, Labruna MB. Rickettsial infections of dogs, horses and ticks in Juiz de Fora, southeastern Brazil, and isolation of Rickettsia rickettsii from Rhipicephalus sanguineus ticks. Med Vet Entomol 2011; 25:148-155. [PMID: 20950356 DOI: 10.1111/j.1365-2915.2010.00915.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The present study was performed in an area endemic for Brazilian spotted fever (BSF) in Juiz de Fora, state of Minas Gerais, Brazil, during the years 2007 and 2008, when fatal cases of BSF (caused by Rickettsia rickettsii) were reported. Adult ticks (Acari: Ixodidae) identified as Rhipicephalus sanguineus (Latreille) and Amblyomma cajennense (Fabricius) were collected from dogs and horses, respectively, and tested by polymerase chain reaction (PCR). Overall, 13.1% of the Rh. sanguineus ticks and none of the A. cajennense were found to be infected with R. rickettsii. Two isolates of R. rickettsii were successfully established in Vero cell culture from two Rh. sanguineus ticks. An indirect immunofluorescence assay (IFA) using R. rickettsii antigens detected blood serological reaction to R. rickettsii in 67.9% (53/78) of dogs and 41.0% (16/39) of horses living in the study area. Larval offspring from two Rh. sanguineus engorged females, naturally infected by R. rickettsii, were reared to adult stage in the laboratory. All active stages (larvae, nymphs, adults) remained 100% infected by R. rickettsii, which was efficiently transmitted to naïve rabbits. Overall, the results of the present study indicate a potential risk for transmission of R. rickettsii to humans by Rh. sanguineus, an occurrence yet to be documented in Brazil.
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Affiliation(s)
- R C Pacheco
- Department of Basic Sciences and Animal Production, Faculty of Veterinary Medicine, Federal University of Mato Grosso, Cuiabá, MT, Brazil
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Kuo CC, Huang CL, Wang HC. Identification of potential hosts and vectors of scrub typhus and tick-borne spotted fever group rickettsiae in eastern Taiwan. Med Vet Entomol 2011; 25:169-177. [PMID: 21223345 DOI: 10.1111/j.1365-2915.2010.00941.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Scrub typhus and tick-borne spotted fever group (SFG) rickettsioses are transmitted by chiggers (larval trombiculid mites) and hard ticks, respectively. We assessed exposure to these disease vectors by extensively sampling both chiggers and ticks and their small mammal hosts in eastern Taiwan during 2007 and 2008. The striped field mouse Apodemus agrarius Pallas (Rodentia: Muridae) was the most common of the small mammals (36.1% of 1393 captures) and presented the highest rate of infestation with both chiggers (47.8% of 110 760) and ticks (78.1% of 1431). Leptotrombidium imphalum Vercammen-Grandjean & Langston (Trombidiformes: Trombiculidae) and immature Rhipicephalus haemaphysaloides Supino (Ixodida: Ixodidae) were the most abundant chiggers (84.5%) and ticks (>99%) identified, respectively. Immunofluorescent antibody assay revealed high seropositive rates of rodents against Orientia tsutsugamushi Hyashi (Rickettsiales: Rickettsiaceae), the aetiological agent of scrub typhus (70.0% of 437 rodents), and tick-borne SFG rickettsiae (91.9% of 418 rodents). The current study represents a first step towards elucidating the potential hosts and vectors in the enzootic transmission of O. tsutsugamushi and tick-borne SFG rickettsiae in Taiwan. Further studies should focus on characterizing pathogens in L. imphalum and R. haemaphysaloides, as well as the proclivity of both vectors to humans. Uncovering the main hosts of adult ticks is also critical for the prevention of SFG rickettsial infections.
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Affiliation(s)
- C C Kuo
- Research and Diagnostic Centre, Centres for Disease Control, Taipei, Taiwan, R.O.C
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Hidalgo M, Vesga JF, Lizarazo D, Valbuena G. A survey of antibodies against Rickettsia rickettsii and Ehrlichia chafeensis in domestic animals from a rural area of Colombia. Am J Trop Med Hyg 2009; 80:1029-1030. [PMID: 19478270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
In a rural area of Colombia endemic for Rocky Mountain spotted fever, we performed indirect immunofluorescent antibody assays for Rickettsia spp. and Ehrlichia spp. using sera from randomly sampled dogs and horses to test the use of domestic animals as possible sentinels. Antibodies against Ehrlichia spp. were detected in 8 dogs (31.8%). Antibody titers against Rickettsia rickettsii antigen were positive in 4 dogs (18.2%) and 26 horses (16.3%). These values, albeit not directly comparable, are lower than those previously reported for humans in this region. A systemic approach to understanding dynamics of transmission is needed before implementing the use of domestic animals for disease surveillance activities.
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Affiliation(s)
- Marylin Hidalgo
- Grupo de Microbiología, Instituto Nacional de Salud, Bogotá, Colombia
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Scorpio DG, Wachtman LM, Tunin RS, Barat NC, Garyu JW, Dumler JS. Retrospective clinical and molecular analysis of conditioned laboratory dogs (Canis familiaris) with serologic reactions to Ehrlichia canis, Borrelia burgdorferi, and Rickettsia rickettsii. J Am Assoc Lab Anim Sci 2008; 47:23-28. [PMID: 18947166 PMCID: PMC2691535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 01/29/2008] [Accepted: 04/22/2008] [Indexed: 05/27/2023]
Abstract
Dogs are susceptible to different tickborne infections, including members of the Anaplasmataceae (Ehrlichia canis, E. ewingii, E. chaffeensis, Anaplasma phagocytophilum, A. platys), Borrelia burgdorferi, and Rickettsia rickettsii. These diseases can manifest with clinical signs including fever, anorexia, malaise, lameness, rash, and bleeding episodes; however, these signs are nonpathognomonic, and infections can occur in the absence of clinical signs. Hematologic abnormalities can include leukopenia, thrombocytopenia, hyperproteinemia and hypergammaglobulinemia. In biomedical research, diseases such as canine monocytic ehrlichiosis, Lyme disease, and Rocky Mountain spotted fever may cause morbidity among exposed dogs and confound research results. Random-source dogs are susceptible to these diseases because of their increased risk of arthropod exposure. Nonpurpose bred, randomly selected conditioned dogs (n = 21) were examined; blood samples were taken for hematology, biochemistry analysis, tickborne pathogen serology, and PCR. Of these, 2 dogs (10% of the population) presented with illness characterized by fever, malaise, lameness, or hemostatic abnormalities, and 15 (71%) had antibodies to one or more tickborne pathogens. No specific hematologic or biochemical differences were apparent between seronegative dogs and seropositive dogs reactive to all 3 pathogens. E. canis and B. burgdorferi PCR of tissues and blood were negative for all dogs. PCR amplification of several Ehrlichia and Anaplasma genes yielded no positive samples. From this cohort of dogs, serologic and molecular results indicate prior exposure without active infection or clinical disease. Exposure to and potential for infection with these bacteria and other pathogens may contribute to blood and tissue alterations that could confound experiments and lead to misinterpretation of data in canine models.
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Affiliation(s)
- Diana G Scorpio
- Department of Molecular and Comparative Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Kidd L, Hegarty B, Sexton D, Breitschwerdt E. Molecular characterization of Rickettsia rickettsii infecting dogs and people in North Carolina. Ann N Y Acad Sci 2007; 1078:400-9. [PMID: 17114748 DOI: 10.1196/annals.1374.079] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Rocky Mountain spotted fever (RMST) is an important cause of morbidity and mortality in people and dogs in the United States. Disease manifestations are strikingly similar in both species, and illness in dogs can precede illness in people. R. rickettsii has been identified as a Select Agent by the CDC as a Category C priority pathogen by the National Institute of Allergic and Infectious Diseases because it is amenable to use as a bioterror agent. The clinical and temporal relationship of naturally occurring diseases in dogs and people suggests that dogs could serve as sentinels for natural infection and bioterrorist attacks using this organism. Recognizing genetic modifications in naturally occurring disease agents in order to distinguish them from intentionally released agents are priorities put forth by the NIAID. To determine whether the rickettsiae naturally infecting dogs is the same as those that infect persons in a given geographical region, we characterized rickettsial isolates obtained from three dogs and two persons diagnosed with RMSF in North Carolina. Portions of three genes (ompA, rrs, and gltA) amplified by PCR were cloned and sequenced or directly sequenced. Reactions were run in duplicate in forward and reverse directions. Gene sequences were aligned with known sequences deposited in GenBank and with each other. Sequences of the 5' region of the ompA gene were 100% homologous with a tick strain (Bitterroot) of R. rickettsii for all five isolates. Sequences of the rrs gene were 99.8 99.9% homologous with a tick strain (Sawtooth) of R. rickettsii. rrs gene sequences from one dog and the two persons was identical. Sequences of one dog isolate differed from these by one base pair. Sequences from another dog isolate differed by two base pairs. Sequences of the gltA gene are pending. This confirms on a molecular level that R. rickettsii causing naturally occurring RMSF in dogs in North Carolina is highly homologous to R. rickettsii that causes the disease in people in the same region. Sequence data will be deposited in GenBank, thereby providing genetic information regarding naturally occurring R. rickettsii.
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Affiliation(s)
- Linda Kidd
- TheScripps Research Institute, Department of Immunology, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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17
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Abstract
A serosurvey of free-roaming dogs for antibodies to spotted fever group rickettsiae was conducted using archival samples that had been collected in the White Mountain region of eastern Arizona during a plague study in 1996. Immunoglobulin G antibodies to Rickettsia rickettsii (5.1%) and to R. rhipicephali (3.6%) were demonstrated, and no cross-reactive samples were identified. This study indicates that R. rickettsii was likely present in the dog populations in this area prior to the recognition of human cases of Rocky Mountain spotted fever (RMSF). The role of dogs as short-term reservoirs and primary hosts for the vector tick, Rhipicephalus sanguineus, should receive closer attention.
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Affiliation(s)
- William L Nicholson
- Viral and Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Mail Stop G-13, 1600 Clifton Road, Atlanta, GA 30333, USA.
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Abstract
To obtain data about select zoonotic and other infectious diseases in free-ranging predators in five ecoregions in Nebraska, sera were collected from 67 coyotes (Canis latrans) and 63 raccoons (Procyon lotor) from November 2002 through January 2003. For coyotes, antibodies were detected against canine distemper virus (CDV, 61%), Francisella tularensis (32%), Rickettsia rickettsi (13%), and flaviviruses (48%). None of the coyote sera had antibodies to Borrelia burgdorferi, Brucella canis, or six serovars of Leptospira interrogans. Because serologic cross-reactivity exists among flaviviruses, 14 sera from flavivirus-positive coyotes were also tested for St. Louis encephalitis virus (SLE) antibodies and two (14%) were positive, suggesting that up to 48% of coyotes tested had antibodies against West Nile virus (WNV). For raccoons, antibodies were detected against CDV (33%), F. tularensis (38%), and three serovars of L. interrogans (11%).
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Affiliation(s)
- Richard Bischof
- Nebraska Game and Parks Commission, 2200 North 33rd Street, Lincoln, Nebraska 68503-0370, USA.
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19
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Abstract
Five dogs from the northeastern United States were presented with clinical signs of neurological disease associated with Rocky Mountain spotted fever (RMSF) infection. Four of the five dogs had vestibular system dysfunction. Other neurological signs included paresis, tremors, and changes in mentation. All of the dogs had an elevated indirect fluorescent antibody titer or a positive semiquantitative enzyme screening immunoassay titer for Rickettsia rickettsii at the time of presentation. Although a higher mortality rate has been reported for dogs with neurological symptoms and RMSF infection, all of the dogs in this study improved with appropriate medical therapy and supportive care.
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Affiliation(s)
- Jessica S Mikszewski
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6010, USA
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20
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Abstract
Two dogs with testicular swelling were sonographically diagnosed with orchitis and were subsequently diagnosed with Rocky Mountain spotted fever (RMSF). Use of both gray scale and color Doppler sonography allowed for differentiation of orchitis from neoplasia and torsion. While only experimentally induced RMSF is reported to cause orchitis in dogs, it should be considered in any dog with vascular insult to the testes, especially when other signs of systemic illness are involved.
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Affiliation(s)
- Christopher P Ober
- Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, 4700 Hillsborough Street, Raleigh, NC 27606, USA
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Eremeeva ME, Liang Z, Paddock C, Zaki S, Vandenbergh JG, Dasch GA, Silverman DJ. Rickettsia rickettsii infection in the pine vole, Microtus pinetorum: kinetics of infection and quantitation of antioxidant enzyme gene expression by RT-PCR. Ann N Y Acad Sci 2003; 990:468-73. [PMID: 12860675 DOI: 10.1111/j.1749-6632.2003.tb07412.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The pine vole, Microtus pinetorum, was evaluated as a laboratory animal model for infection with Rickettsia rickettsii. Voles demonstrated signs of acute disease, and 45% of infected animals died following intraperitoneal infection with 3 x 10(6) plaque forming units of R. rickettsii. Spleen, liver, kidney, lung, brain, testes and blood were analyzed for rickettsial burden by a quantitative PCR assay. The distribution of rickettsiae in tissues during the course of infection was determined by immunohistochemical staining and pathological changes in tissues were correlated with the clinical severity of infection. Quantitative RT-PCR assays were designed to measure the mRNA levels of the antioxidant enzyme genes for catalase, glutathione peroxidase, glutathione reductase, heme oxygenase, Cu-Zn superoxide dismutase (SOD) and Mn-SOD, and 2 housekeeping genes, actin and glyceraldehyde phosphate dehydrogenase. Tissues from acutely ill animals on days 2 to 6 of infection, convalescent animals, and uninfected control animals were studied. The number of transcripts of each enzyme gene was determined and compared to the degree of rickettsial infection present. These studies demonstrate that the pine vole is a valuable experimental model for studying infection with R. rickettsii. Our results provide the first experimental evidence that R. rickettsii causes alteration(s) of the anti-oxidant system in vivo.
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Affiliation(s)
- Marina E Eremeeva
- Viral and Rickettsial Zoonoses Branch, Infectious Disease Pathology Activity, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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Galvão MAM, Lamounier JA, Bonomo E, Tropia MS, Rezende EG, Calic SB, Chamone CB, Machado MC, Otoni MEA, Leite RC, Caram C, Mafra CL, Walker DH. [Emerging and reemerging rickettsiosis in an endemic area of Minas Gerais State, Brazil]. CAD SAUDE PUBLICA 2002; 18:1593-7. [PMID: 12488886 DOI: 10.1590/s0102-311x2002000600013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This article describes a serological survey for rickettsiosis in the county of Novo Cruzeiro, Minas Gerais State, Brazil, in 1998, testing schoolchildren and dogs. Sera included 331 samples from schoolchildren from an endemic area and 142 samples from schoolchildren from a non-endemic area in the county. All children examined were healthy and had not reported clinical symptoms of Brazilian spotted fever prior to the serological survey. Some 35 children in the endemic area were reactive to Rickettsia rickettsiiby indirect fluorescent antibody (IFA) with a titer of 1:64, corresponding to 10.6%. Sera from 73 dogs were tested, showing seroreactivity (IFA 1:64) to Rickettsia rickettsi, Ehrlichia chaffeensis, and Ehrlichia canisin 3 (4.11%), 11 (15.07%), and 13 (17.81%), respectively. The results in schoolchildren and the presence of canine seroreactivity to Ehrlichiaspecies that are potentially pathogenic to humans suggests the risk of transmission of other Rickettsiaein the study area.
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Affiliation(s)
- Márcio A M Galvão
- Departamento de Nutrição Clínica e Social, Escola de Nutrição, Universidade Federal de Ouro Preto, Ouro Preto, MG, 35400-000, Brasil.
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Rozental T, Bustamante MC, Amorim M, Serra-Freire NM, Lemos ERSD. Evidence of spotted fever group rickettsiae in state of Rio de Janeiro, Brazil. Rev Inst Med Trop Sao Paulo 2002; 44:155-8. [PMID: 12163909 DOI: 10.1590/s0036-46652002000300008] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ticks were obtained from dogs from February to September of 1999 at weekly intervals, in the County of Piraí, State of Rio de Janeiro. Four hundred seventy four ixodids were taxonomically identified, 103 Amblyomma cajennense, seven Amblyomma ovale, 209 Rhipicephalus sanguineus, and 155 Amblyomma sp. An hemolymph test associated with Giemsa's stain revealed two specimens in 163 ticks tested (R. sanguineus and Amblyomma sp), containing rickettsia-like organisms. Direct immunofluorescence verified the presence of spotted fever group rickettsia in one specimen of R. sanguineus. Considering the limited information on rickettsiosis in Brazil, principally in relation to the vectors involved in perpetuating it in foci, these preliminary results give us an idea on the importance of infection in ticks, allowing to expand our knowledge on this zoonosis.
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Affiliation(s)
- Tatiana Rozental
- Department of Virology, Institute Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ, Brasil.
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Paddock CD, Brenner O, Vaid C, Boyd DB, Berg JM, Joseph RJ, Zaki SR, Childs JE. Short report: concurrent Rocky Mountain spotted fever in a dog and its owner. Am J Trop Med Hyg 2002; 66:197-9. [PMID: 12135293 DOI: 10.4269/ajtmh.2002.66.197] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A sequential occurrence of Rocky Mountain spotted fever (RMSF) in a dog and its owner is described. Diagnosis of RMSF in the animal guided subsequent testing for and diagnosis of the same disease in the human patient. Previous reports of concurrent RMSF in dogs and their owners are reviewed, and the epidemiologic significance of this occurrence is discussed.
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Affiliation(s)
- Christopher D Paddock
- Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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Hinrichsen VL, Whitworth UG, Breitschwerdt EB, Hegarty BC, Mather TN. Assessing the association between the geographic distribution of deer ticks and seropositivity rates to various tick-transmitted disease organisms in dogs. J Am Vet Med Assoc 2001; 218:1092-7. [PMID: 11318358 DOI: 10.2460/javma.2001.218.1092] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine whether the geographic distribution of deer ticks (Ixodes scapularis) was associated with the distribution of dogs seropositive for various tick-transmitted disease organisms (ie, Borrelia burgdorferi, Rickettsia rickettsii, the human granulocytic ehrlichiosis [HGE] agent, Ehrlichia canis, and Bartonella vinsonii subsp berkhoffii). DESIGN Serologic survey. SAMPLE POPULATION Serum samples from 277 dogs in animal shelters and veterinary hospitals in Rhode Island. RESULTS Overall, 143 (52%) dogs were seropositive for B burgdorferi, 59 (21.3%) were seropositive for R rickettsii, 40 (14.4%) were seropositive for the HGE agent, 8 (2.9%) were seropositive for E canis, and 6 (2.2%) were seropositive for B vinsonii. Regression analysis indicated that the natural logarithm of nymphal deer tick abundance was correlated with rate of seropositivity to the HGE agent and to B burgdorferi but not to rate of seropositivity to R rickettsii, E canis, or B vinsonii. Percentages of samples seropositive for B burgdorferi, R rickettsii, the HGE agent, and E canis were significantly higher for samples from the southwestern part of the state where ticks in general and deer ticks in particular are abundant than for samples from the northern and eastern portions of the state, where ticks are relatively rare. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that all 5 disease agents are in Rhode Island and pose a risk to dogs and humans. Knowledge concerning tick distributions may be useful in predicting the pattern of disease associated with particular tick species and may aid diagnostic, prevention, and control efforts.
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Affiliation(s)
- V L Hinrichsen
- Center for Vector-Borne Disease, University of Rhode Island, Kingston 02881, USA
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Abstract
Rocky Mountain spotted fever (RMSF) was diagnosed in 30 dogs examined at North Carolina State University, Veterinary Teaching Hospital between 1984 and 1997. Historical, physical examination, and laboratory abnormalities were reviewed. Diagnostic criteria included a four-fold rise in antibody titer to Rickettsia rickettsii (R. rickettsii) (n=15) or a single R. rickettsii antibody titer of 1:1,024 or greater (n=15; when this initial titer was determined one week or more after the onset of clinical signs). Fifteen (50%) dogs were greater than seven years of age, and 13 (43%) dogs were between two and seven years of age. There was no sex predilection. Only five (17%) dogs had a history of known tick exposure. Presumably due to delayed diagnosis, dogs with antibody titers of 1:1,024 or greater at the time of presentation had a higher incidence of more severe neurological dysfunction (e.g., ataxia, hyperesthesia, vestibular disease, and seizures) and cutaneous lesions (e.g., hyperemia, edema, petechiae, ecchymoses, and necrosis). Laboratory findings included anemia, leukocytosis accompanied by toxic granulation of neutrophils, hypoalbuminemia, and coagulation abnormalities; signs were generally more severe in the 15 dogs with R. rickettsii antibody titers of 1:1,024 or greater at the time of presentation. Twelve (40%) dogs in this study were severely thrombocytopenic (less than 75 x10(3) platelets/microl; reference range, 200 to 450 x 10(3)/microl), without clinical evidence of fulminant disseminated intravascular coagulation. In this study, the survival rate following R. rickettsii infection was 100%.
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Affiliation(s)
- A M Gasser
- Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA
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Abstract
Dogs that live in tick-infested areas are at risk for contracting rickettsial infections. Clinical signs associated with ehrlichiosis or Rocky Mountain spotted fever may be dramatic or mild. Clinicians must consider the possibility of rickettsial diseases to request laboratory tests that will permit a proper diagnosis. Specific antimicrobial therapy usually brings about clinical improvement, although some dogs may not be cleared of rickettsial organisms, even with prolonged treatment. A small percentage of dogs die of rickettsial infections, either in the acute stage or owing to chronic bone marrow suppression and generalized debilitation. Ocular lesions are an important clinical sign in canine rickettsial infections and may aid the clinician in making a diagnosis and monitoring response to therapy.
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Affiliation(s)
- J Stiles
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA
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28
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Abstract
Central nervous system (CNS) complications of bacterial otitis media/interna are an infrequent occurrence in human patients and have rarely been reported in the veterinary literature. Early recognition of CNS involvement and the use of appropriate diagnostic tests to characterize the nature of the lesion(s) are crucial in determining the best course of treatment. In this paper, the authors describe a dog with bacterial meningoencephalitis secondary to otitis media/interna.
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Affiliation(s)
- E A Spangler
- Texas Veterinary Medical Center, Texas A&M University, College Station 77843-4474, USA
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29
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Grindem CB, Breitschwerdt EB, Perkins PC, Cullins LD, Thomas TJ, Hegarty BC. Platelet-associated immunoglobulin (antiplatelet antibody) in canine Rocky Mountain spotted fever and ehrlichiosis. J Am Anim Hosp Assoc 1999; 35:56-61. [PMID: 9934930 DOI: 10.5326/15473317-35-1-56] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Antiplatelet antibodies were detected in the sera of dogs with naturally occurring and experimentally induced Rickettsia rickettsii and Ehrlichia canis infections. This is the first known report documenting elevated platelet-associated immunoglobulin (PAIg) titers in Rocky Mountain spotted fever (RMSF) infections. In the naturally occurring RMSF infections and ehrlichiosis, the antibodies persisted for weeks or months, even when the platelet counts had normalized. Results of this study indicate an immunological component for rickettsial thrombocytopenia. Therefore, current therapeutic recommendations, especially regarding avoiding the use of immunosuppressive drugs in patients with rickettsial diseases, need to be critically reviewed.
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Affiliation(s)
- C B Grindem
- Department of Microbiology, Pathology, and Parasitology, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA
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30
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Ibrahim IN, Okabayashi T, Lestari EW, Yanase T, Muramatsu Y, Ueno H, Morita C. Serosurvey of wild rodents for Rickettsioses (spotted fever, murine typhus and Q fever) in Java Island, Indonesia. Eur J Epidemiol 1999; 15:89-93. [PMID: 10099001 DOI: 10.1023/a:1007547721171] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The prevalence of antibodies against spotted fever group rickettsia (SFGR), murine typhus and Q fever were investigated in wild rats captured in Indonesia. Sera of 327 rats were collected from Jakarta and Boyolali on Java Island. The prevalences of antibodies against SFGR and murine typhus were 128 (39.1%) and 48 (14.7%), respectively. Antibodies against Q fever were not detected in these serum samples. Antibodies against SFGR were found in all species of rats (20.8-51.9%). The antibody positive rate against murine typhus in Rattus norvegicus (38.0%) was significantly higher than that in other rat species (0-4.8%, p<0.01). The antibody positive rates against SFGR and murine typhus in rats captured in Jakarta were significantly higher than those in rats captured in Boyolali (p<0.01). In this survey, all species of rats had antibodies against SFGR, indicating that the 4 species of tested rats (R. norvegicus, R. rattus, R. exulans, R. tiomanicus) were infected with SFGR and that SFGR may infest the whole of Java Island. Most of the rats that were antibody-positive against murine typhus were captured in Jakarta. Therefore, R. norvegicus and R. rattus are likely to be important hosts of murine typhus in Jakarta. The antibody-positive rates against SFGR and murine typhus in rats captured in the dry season were significantly higher than those in rats captured in the rainy season. This may coincide with the active periods of ticks and fleas in Indonesia.
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Affiliation(s)
- I N Ibrahim
- Health-Ecology Research Center, National Institute of Health Research and Development, Indonesia
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31
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Abstract
Inflammatory diseases of the central nervous system (CNS) are important causes of seizures in dogs. Specific diseases include canine distemper, rabies, cryptococcosis, coccidioidomycosis, toxoplasmosis, neosporosis, Rocky Mountain spotted fever, ehrlichiosis, granulomatous meningoencephalomyelitis, and pug dog encephalitis. Inflammatory disorders should be considered when a dog with seizures has persistent neurological deficits, suffers an onset of seizures at less than 1 or greater than 5 years of age, or exhibits signs of systemic illness. A thorough history, examination, and analysis of cerebrospinal fluid are important in the diagnosis of inflammatory diseases. However, even with extensive diagnostic testing, a specific etiology is identified in less than two thirds of dogs with inflammatory diseases of the CNS.
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Affiliation(s)
- W B Thomas
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071, USA
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32
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Abstract
Sixteen beagle dogs were injected intradermally with Rickettsia rickettsii. The dogs were divided into four groups (n = 4): 1) infected, non-treated control; 2) infected, treated with doxycycline; 3) infected, treated with doxycycline and an anti-inflammatory dose of corticosteroid; and 4) infected, treated with doxycycline and an immunosuppressive dose of corticosteroid. Thoracic radiographs were made and ocular fluorescein angiography was performed on days 6, 10, 17 post-inoculation. A mild interstitial lung opacity was noted in 4/16 dogs on day 6, 5/16 on day 10 and 3/16 on day 17 post-inoculation. Increased retinal vascular permeability was noted in 8/16 dogs on day 6, 3/16 on day 10 and 1/16 on day 17 post-inoculation. Correlation between the presence of radiographic and retinal lesions was not significant (p = 0.08). Eleven, naturally infected, dogs with thoracic radiographs and a final diagnosis of RMSF were also evaluated. Four of the 11 dogs had an unstructured interstitial pattern. Dogs with acute, experimentally-infected or naturally-occurring RMSF may have subtle pulmonary changes characterized by an unstructured interstitial pattern.
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Affiliation(s)
- W T Drost
- Department of Anatomy, Physiological Sciences and Radiology, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA
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33
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Greene CE, Marks MA, Lappin MR, Breitschwerdt EB, Wolski NA, Burgdorfer W. Comparison of latex agglutination, indirect immunofluorescent antibody, and enzyme immunoassay methods for serodiagnosis of Rocky Mountain spotted fever in dogs. Am J Vet Res 1993; 54:20-8. [PMID: 8427468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Indirect immunofluorescent antibody (IFA), latex agglutination (LA), and enzyme immunoassay (EIA) methods were compared for evaluation of the serum antibody responses of dogs experimentally and naturally exposed to spotted fever-group rickettsiae. Selected sera (obtained on days 1, 42, 53, 124, 145, 236, 255, 264, and 292) were examined from three 8-month-old female Beagles inoculated with Rickettsia rickettsii on days 34 and 250 of the study. A second group of dogs comprised three 8-month-old female Beagles inoculated with R montana on days 34 and 102. Subsequently, these dogs were inoculated with R rickettsii on day 250. Serum samples were obtained from the second group of dogs on days 1, 96, 103, 132, 180, 215, 292, and 494. A third group consisted of 21 naturally exposed dogs, from which sequentially obtained serum samples were available, and which had clinical signs compatible with Rocky Mountain spotted fever. Clinical signs of disease in dogs of the third group resolved after treatment with tetracycline (22 mg/kg of body weight, PO, q 8 h) was instituted. At least 2 sequentially obtained serum samples from each dog were tested. In general, the first sample was obtained just prior to treatment and the convalescent serum samples were obtained at weekly or greater intervals thereafter. For correlation and reactivity data, an IFA test for IgG/IgM (using heavy and light chains-specific conjugate) was used as the reference standard for comparison of results with those of the other tests.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C E Greene
- Department of Small Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602
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34
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Breitschwerdt EB, Levy MG, Davidson MG, Walker DH, Burgdorfer W, Curtis BC, Babineau CA. Kinetics of IgM and IgG responses to experimental and naturally acquired Rickettsia rickettsii infection in dogs. Am J Vet Res 1990; 51:1312-6. [PMID: 2117411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The kinetics of specific IgM and IgG antibody response was characterized in four 9-month-old Beagles after inoculation of 2 x 10(2) plaque-forming units (PFU) of Sheila Smith strain of Rickettsia rickettsii. Immunoglobulin M antibodies were first detected by indirect immunofluorescence on postinoculation (PI) day 9, peaked by PI day 20, and were no longer detectable by PI day 80. Immunoglobulin G antibodies became detectable between PI days 22 and 28, peaked by PI day 42, and decreased gradually through PI day 130. Subsequent challenges with R rickettsii on PI days 216 (2 x 10(2) PFU/dog) and 1,029 (5 x 10(4) tissue culture infective dose [TCID50]/dog) resulted in slightly different serologic responses. The initial challenge exposure failed to increase the concentration of IgG antibodies and induced only low concentrations of IgM antibodies. After the second challenge inoculation, IgM antibodies were not detectable and the concentration IgG antibodies increased slightly. Clinical abnormalities and seroconversion were documented in control dogs following each challenge exposure. Examination of acute and convalescent serum samples from 55 dogs in which Rocky Mountain spotted fever was suspected clinically suggested that sole evaluation of IgM antibodies in acute-phase serum would result in inaccurate diagnoses because of false-positive and -negative results. Use of a composite conjugate that detects IgM and IgG antibodies to R rickettsii appears to be satisfactory for diagnostic purposes; however, concurrent quantitation of IgM antibodies may facilitate serodiagnosis in a select group of dogs in which a four-fold increase in convalescent antibody titer is not detected by use of the composite conjugate.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- E B Breitschwerdt
- Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606
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35
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Davidson MG, Breitschwerdt EB, Walker DH, Levy MG, Carlson CS, Hardie EM, Grindem CA, Nasisse MP. Vascular permeability and coagulation during Rickettsia rickettsii infection in dogs. Am J Vet Res 1990; 51:165-70. [PMID: 2105679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The vascular permeability of the ocular fundus, alterations in the coagulation system, and plasma concentrations of thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were studied in dogs following intradermal inoculation with 5 x 10(5) TCID50 of Rickettsia rickettsii. Twenty-four to 48 hours after the onset of fever and rickettsemia, multifocal areas of retinal vasculitis were evident, which corresponded to areas of altered vascular permeability demonstrated by fluorescein angiography. The number and intensity of retinal vessels with sodium fluorescein leakage peaked during the second week after inoculation, and retinal vascular permeability remained altered during the third week of infection, well past the phase of clinical and clinicopathologic recovery. Development of retinal vasculitic foci was associated with thrombocytopenia, increased concentrations of circulating fibrinogen, and slight prolongation of activated partial thromboplastin time. Increased concentrations of fibrin/fibrinogen degradation products were detected in 4 of 9 dogs. Despite the degree of vascular endothelial damage evident on fluorescein angiographic and histologic studies in these dogs, plasma TXB2 and 6-keto-PGF1 alpha concentrations were not increased.
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Affiliation(s)
- M G Davidson
- Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606
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36
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Abstract
A serologic survey for the agents of Rocky Mountain spotted fever (RMSF) (Rickettsia rickettsii), Borrelia spp. including the causative agent for Lyme disease (Borrelia burgdorferi), and plague (Yersinia pestis) was conducted on blood samples collected from 30 and 46 black-tailed jack rabbits (Lepus californicus) from an urban environment in Lubbock, Texas (USA) during winter 1987 and the following spring 1988, respectively. Antibody titers to the agents of RMSF and borreliosis were detected in sera of 28 and 1% of the jack rabbits, respectively. Neither organisms (rickettsiae and/or spirochetes) nor their associated antigens were detected in any of the tissue or whole blood samples; plague antibodies were not detected in the 76 jack rabbits sampled. Four of 18 ticks (Dermacentor parumapertus) removed from 12 jack rabbits were positive for RMSF using the fluorescent antibody test. The black-tailed jack rabbit is a common wildlife species living in close proximity to higher density human populations in many areas of the southwestern United States. Our results indicate the potential importance of urban populations of this mammal as reservoirs for at least one important zoonotic disease, RMSF, in western Texas.
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Affiliation(s)
- S E Henke
- Wildlife Management, Texas Tech University, Lubbock 79409
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37
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Weiser IB, Greene CE. Dermal necrosis associated with Rocky Mountain spotted fever in four dogs. J Am Vet Med Assoc 1989; 195:1756-8. [PMID: 2599964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Four dogs with Rocky Mountain spotted fever developed extensive dermal necrosis. Factors contributing to this complication included delay in initiation of appropriate therapy.
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Affiliation(s)
- I B Weiser
- Department of Small Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602
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38
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Rodgers SJ, Morton RJ, Baldwin CA. A serological survey of Ehrlichia canis, Ehrlichia equi, Rickettsia rickettsii, and Borrelia burgdorferi in dogs in Oklahoma. J Vet Diagn Invest 1989; 1:154-9. [PMID: 2518693 DOI: 10.1177/104063878900100212] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Serum samples from 259 dogs were tested for antibodies to Ehrlichia canis, Ehrlichia equi, Rickettsia rickettsii, and Borrelia burgdorferi using the indirect fluorescent antibody test. The sera were obtained from submissions to the Oklahoma Animal Disease Diagnostic Laboratory during a 14-month period from June 1986 through July 1987. The rate for positive antibody titers to E. canis was 53%, to E. equi was 33%, to R. rickettsii was 38%, and to B. burgdorferi was 18%. Higher percentages of sera serologically positive to E. canis were found in the spring through the fall months, but there were no seasonal variations for E. equi, R. rickettsii, and B. burgdorferi. There was no consistent pattern of titers to the 4 antigens when age-groups of the dogs were compared. Forty-four different breeds were tested.
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Affiliation(s)
- S J Rodgers
- Oklahoma Animal Disease Diagnostic Laboratory, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078
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39
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Davidson MG, Breitschwerdt EB, Nasisse MP, Roberts SM. Ocular manifestations of Rocky Mountain spotted fever in dogs. J Am Vet Med Assoc 1989; 194:777-81. [PMID: 2494144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Dogs were examined ophthalmoscopically to determine the prevalence and type of ocular lesions associated with naturally acquired Rocky Mountain spotted fever (RMSF). In a consecutive series of 11 dogs with serologically confirmed RMSF, 9 had ocular involvement reflecting various degrees of vascular damage, including subconjunctival hemorrhage, hyphema, anterior uveitis, iris stromal hemorrhage, retinal petechiae, and focal areas of retinal edema and perivascular inflammatory cell infiltrate. The ophthalmic lesions generally were mild, and most resolved without complication after systemic administration of appropriate antibiotics. The high prevalence of ocular lesions in these dogs suggested that critical ophthalmologic evaluation is a useful diagnostic tool for the early detection and management of RMSF in dogs.
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Affiliation(s)
- M G Davidson
- Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606
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40
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Davidson MG, Breitschwerdt EB, Walker DH, Nasisse MP, Sussman WE. Identification of rickettsiae in cutaneous biopsy specimens from dogs with experimental Rocky Mountain spotted fever. Vet Med (Auckl) 1989; 3:8-11. [PMID: 2494323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Direct immunofluorescence reaction for Rickettsia rickettsii was performed on formalin-fixed, paraffin-embedded cutaneous biopsy specimens collected from dogs with experimental Rocky Mountain spotted fever (RMSF). A technique of trypsin digestion of deparaffinized, rehydrated sections was successful in demonstrating discrete, immunofluorescent organisms in endothelia and adjacent vessel walls in the dermis. R rickettsii was identified only in grossly evident dermal lesions (macular rash or oral vesicles) and was not apparent in randomly collected biopsy specimens from clinically normal inguinal skin. These results suggest that clinical application of this technique for diagnosis of RMSF may be limited in dogs without cutaneous lesions.
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Affiliation(s)
- M G Davidson
- Department of Companion Animal and Special Species Medicine College of Veterinary Medicine, North Carolina State University, Raleigh 27606
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41
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Pletcher JM. Faithful fido fetches fever. Md Med J 1988; 37:288-9. [PMID: 3367719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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42
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Heidt GA, Rucker RA, Kennedy ML, Baeyens ME. Hematology, intestinal parasites, and selected disease antibodies from a population of bobcats (Felis rufus) in central Arkansas. J Wildl Dis 1988; 24:180-3. [PMID: 3352091 DOI: 10.7589/0090-3558-24.1.180] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Eight bobcats with adjoining or overlapping home ranges were examined. Hematological values were within previously reported ranges. Six bobcats demonstrated antibody titers to Toxoplasma gondii. Isospora spp., Taenia taeniaeformis, Spirometra mansoides, Physoloptera rara, Toxocara cati, Strongyloides spp., Trichurus spp., Capillaria spp., and Ancyclostoma spp. were found also in the animals examined. The mean number of parasite species per host was 4.1. All bobcats tested negative for serum antibodies to Rocky Mountain spotted fever (Rickettsia rickettsii). Two bobcats had titers less than or equal to 1:20 for tularemia (Francisiella tularensis), and two were positive for leptospirosis (Leptospira spp.).
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Affiliation(s)
- G A Heidt
- Department of Biology, University of Arkansas, Little Rock 72204
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43
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Greene CE. Rocky Mountain spotted fever. J Am Vet Med Assoc 1987; 191:666-71. [PMID: 3316138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- C E Greene
- Department of Small Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602
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44
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Breitschwerdt EB, Meuten DJ, Walker DH, Levy M, Kennedy K, King M, Curtis B. Canine Rocky Mountain spotted fever: a kennel epizootic. Am J Vet Res 1985; 46:2124-8. [PMID: 4062017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Within a period of 5 consecutive days after the initial observation of illness was made, 7 of 12 Siberian Husky dogs developed clinical signs of Rickettsia rickettsii infection. One dog died and was necropsied. Clinical signs of infection consisted of lethargy, anorexia, ocular and nasal discharges, and neurologic disorder (incoordination and rolling). Scleral blood vessel injection, fever, lymphadenomegaly, splenomegaly, and increased bronchovesicular lung sounds were prominent findings. Clinical laboratory test results identified decreased platelet numbers, variable neutrophil counts, increased serum alkaline phosphatase activity, hyponatremia, hypokalemia, and bilirubinuria. Diagnosis of Rocky Mountain spotted fever was confirmed by serologic evaluation of acute and convalescent sera, using the micro-immunofluorescence technique, and R rickettsii antigen was determined by demonstration of intracellular rickettsial organisms in vascular endothelial cells of brain and lung (stained with carbol-basic fuchsin and aqueous malachite green) and by demonstration of spotted fever-group rickettsiae in tissues by direct fluorescent antibody technique. Near-simultaneous naturally occurring tick-borne infection of 7 dogs with R rickettsii documents an unreported occurrence.
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45
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Greene CE, Burgdorfer W, Cavagnolo R, Philip RN, Peacock MG. Rocky Mountain spotted fever in dogs and its differentiation from canine ehrlichiosis. J Am Vet Med Assoc 1985; 186:465-72. [PMID: 3972706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Rocky Mountain spotted fever (RMSF) or ehrlichiosis was diagnosed in dogs on the basis of specific immunofluorescent testing for each disease. Comparisons between clinical and laboratory findings were made between the 2 diseases. The incidence of RMSF tended to be more seasonal and it affected younger dogs. Purebred dogs appeared to be more susceptible to both diseases. In general, RMSF had a more rapid and severe course of clinical illness than did ehrlichiosis, but acute ehrlichiosis was difficult to differentiate from RMSF. Both diseases were characterized by fever, depression, lymphadenopathy, and signs of neurologic dysfunction; petechial hemorrhages or other signs of hemorrhagic diathesis were evident only in a small proportion of cases. Anemia, leukopenia, and thrombocytopenia were more common in dogs with ehrlichiosis, whereas those with RMSF more often had leukocytosis and thrombocytopenia. Hypoalbuminemia was found in dogs with both diseases, but those with ehrlichiosis usually had concurrent hyperglobulinemia. High serum alkaline phosphatase activity and serum cholesterol concentration, and low serum calcium concentration were more common in dogs with RMSF than with ehrlichiosis. Rising serum titers or positive direct immunofluorescence for Rickettsia rickettsii in skin biopsy specimens were used to confirm RMSF, whereas a single serum titer for Ehrlichia canis enabled detection of ehrlichiosis. In the absence of neurologic deficits and when dogs were treated with tetracycline, dogs with RMSF made a more rapid and consistent recovery than did dogs with ehrlichiosis.
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46
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Smith RC, Gordon JC, Gordon SW, Philip RN. Rocky Mountain spotted fever in an urban canine population. J Am Vet Med Assoc 1983; 183:1451-3. [PMID: 6418697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A survey for the prevalence of Rocky Mountain spotted fever antibodies in dogs from a well-defined endemic area in Columbus, Ohio (Franklin County), was conducted during the summer of 1981. Seventy-three blood samples from dogs in this area were tested by microimmunofluorescence for antibodies to Rickettsia rickettsii and other rickettsial antigens. Thirty-three (45.2%) of these samples were positive for R rickettsii, with titers ranging from 1:8 to 1:2,048. For comparison, 137 blood samples from dogs at the Franklin County Dog Pound also were tested. One dog (0.7%) from the comparison group was seropositive to R rickettsii, with a 1:64 titer. The results indicated a nidus of this disease within the city of Columbus, Ohio.
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47
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48
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Kelly DJ, Osterman JV, Stephenson EH. Rocky Mountain spotted fever in areas of high and low prevalence: survey for canine antibodies to spotted fever rickettsiae. Am J Vet Res 1982; 43:1429-31. [PMID: 6808878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Antibodies to Rickettsia rickettsii were detected by indirect immunofluorescence in sera from 149 of 467 dogs (32%) examined from 4 military installations located in Kentucky, North Carolina, Pennsylvania, and Virginia. The prevalence at individual installations ranged from 4.3% at Fort Knox, Ky, to 63.4% at Fort Bragg, NC. Most of the seropositive dogs were in the working and sporting groups of dogs. The difference in antibody prevalence between sexes was not significant. Serologic responses were related to R rickettsii infection, although antibodies to R montana also were detected in a few of the sera. Comparison of serodiagnostic methods indicated that the indirect fluorescent antibody test was more sensitive than was the indirect hemagglutination test for obtaining survey data on the prevalence of Rocky Mountain spotted fever in the area.
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49
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Hill GD. Rocky Mountain spotted fever in a dog. J Am Vet Med Assoc 1982; 180:26. [PMID: 7056658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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50
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Thornton JT. Rocky mountain spotted fever in dogs and man. Mod Vet Pract 1981; 62:313-5. [PMID: 7278854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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