Conferencias Magistrales. Human Ehrlichiosis and Anaplasmosis in America. Stephen Dumler. A description of Ehrlichia and Anaplasma agents that have been linked to human disease is presented. A particular emphasis is given to Ehrlichia chaffeensis , Anaplasma phagocytophilum , and Ehrlichia canis. The clinical features associated with each agent, as well as the corresponding diagnosis and treatment are also described.
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Thiago F. Martins 3. Felipe S. Krawczak 3. Marcelo B. Labruna 3. The aims of this study were to determine the seroprevalence of Ehrlichia spp. Serum samples from dogs, 16 horses and humans were used.
Fifty-six out of In conclusion, anti- Ehrlichia spp. Additionally, the higher seroprevalence of E. Concluindo, anticorpos anti- Ehrlichia spp. Ehrlichiosis is a tick-borne disease caused by Ehrlichia spp.
The disease is historically endemic in tropical and subtropical regions and has increasingly been recognized, not only in traditionally endemic areas, but also in temperate regions This may be attributed to several factors, including the improved diagnostic tools, and both environmental and climate changes which directly influences the distribution of ticks In some regions of Brazil, dogs and horses are frequently exposed to ticks 29 Dogs and humans are exposed and susceptible to infection by many of the very same tick-borne bacterial pathogens in the order Rickettsiales, including Ehrlichia spp.
Ehrlichia canis is the causative agent of canine monocytic ehrlichiosis and is the main Ehrlichia species present in dogs in Brazil Additionally, E.
In humans there are two recognized diseases to date caused by Ehrlichia species; human monocytic ehrlichiosis HME , caused by Ehrlichia chaffeensis ; and human granulocytic ehrlichiosis HGE due to Ehrlichia ewingii Human ehrlichiosis cases have been serologically identified in Brazil since 6 11 12 ; however, the Ehrlichia species associated with these cases were not identified.
Additional cases of human ehrlichiosis have been serologically diagnosed in other South American countries, including Argentina 45 , Chile 31 , Peru 38 and Venezuela 43 Ticks have never been implicated in the transmission of N.
While clinical cases of EME have been reported in southern and southeastern regions of Brazil 10 17 18 , horses serologically reactive to A. The increasing number of people living in rural settlements in Brazil, with poor-resources and precarious living conditions, inadequate sanitary care, and sanitary education, associated to the presence of pets, production animals, wild animals, and ticks sharing the same environment, may represent an important source of several zoonotic pathogens.
The area is located within the rural perimeter of Alvorada do Sul, 16 km from downtown, m above sea level. The region is subdivided in 60 homesteads, each with an area of approximately 12 hectares, amounting to hectares. The main activity of subsistence is the cultivation of grains and vegetables. There is a barrage close to the area, where the habitants often fish and bath. This region provides the maintenance of various ticks, to which dogs, horses, and humans are continually exposed.
Study design: According to the seasonal dynamics of adult ticks 50 52 , samples were collected in March , which represents the end of the summer in the South hemisphere. Sampling was performed house-to-house, comprising all 60 homesteads of the area. A questionnaire focused on epidemiological aspects was given to each owner.
Breed, age, gender of their dogs and horses, and presence or previous contact with ticks were evaluated. Age, gender and history of previous contact with ticks were also addressed for humans. Collection of ticks: A total of and 26 tick specimens were collected from dogs and horses, respectively. Ticks were classified according to taxonomic keys 2 20 34 Detection of anti- Ehrlichia spp antibodies: Serum samples of dogs and 16 horses were tested for E.
The kit also detects antibodies anti- A. Anti- Ehrlichia spp. Crude antigens were produced by culturing ehrlichiae in DH82 cells, as previously described 1 Horse samples were titred with a dilution of of fluorescein isothiocyanate-conjugated rabbit anti-horse IgG Sigma-Aldrich, St. Louis, MO. Titers were determined to the largest dilution in which fluorescence was visualized around the bacteria endpoint titers.
Statistical analysis: The Chi-square or Fisher's exact test were used to determine the difference between whether individual factors were associated with seropositivity to Ehrlichia spp. A total of dogs were sampled, 83 All were mixed breed, with ages varying from six months to 12 years. No significant association was found between gender or presence of ticks, and seropositivity to E. Data on E.
Additionally, anti- A. Anti- B. Horses included nine Ten out of 16 Antibodies titers ranged from to for E. Additionally, antibodies anti- B. Antibodies anti- A. From the total of seropositive samples, two reacted for both agents. Antibodies titers ranged from 64 to for E.
No significant association was found between age, gender or previous exposure to tick bites, and seropositivity to Ehrlichia spp. Seropositive human samples were: female, 12 years-old, and kept five dogs at home, all seropositive for E. All humans recalled tick and insect bites, and recollected acute febrile syndromes in the past. Two tick species were identified: A. Despite this test has been developed for screening canine samples 8 , the assay uses antigen-specific conjugate and was previously validated for screening B.
Thus, differences in the number of seropositive horses found by each test were somewhat expected, since the commercial ELISA rapid test utilizes synthetic peptides from p30 and p outer membrane proteins of E. A weak cross-reactivity between N. Recently developed Western blot tests coupled with serum absorption techniques have been used in order to identify the organisms involved and solve the serological cross-reactivity between these agents In the present study, horse antibody endpoint titers ranged from to for E.
Moreover, Ehrlichia canis is transmitted through the bite of the brown dog tick R. Neither horse infestations by R. In addition, no data are currently available on the vector competence of A.
On the other hand, ticks have never been implicated in the transmission of N. Thus, authors did not exclude the possibility on the involvement of a not-yet-described Ehrlichia species in the population of horses herein studied, which should be further molecularly identified and characterized.
Although clinical cases of human ehrlichiosis have been reported in Brazil by using E. Although molecular detection of E. Seropositivity to E. Serological surveys of E. Previous studies have reported that male dogs previously exposed to tick bites were at high risk of being seropositive for E.
In the present study, besides Thus, seroprevalence for E. Antibodies anti- Ehrlichia species were found in horses by two different serological methods. However, the lack of a molecular characterization precludes any conclusion regarding the agent involved. The higher E. This study is part of a PhD degree of Rafael F.
Vieira at the Universidade Estadual de Londrina. Cienc Rural. Notas de Ixodologia. Mem Inst Oswaldo Cruz. Nested polymerase chain reaction for detection of Ehrlichia risticii genomic DNA in infected horses. Vet Parasitol. Antigenic characterization of ehrlichiae: protein immunoblotting of Ehrlichia canis, Ehrlichia sennetsu, and Ehrlichia risticii. J Clin Microbiol. Centers for Disease Control and Prevention. Division of viral and rickettsial diseases: indirect fluorescent antibody technique for the detection of rickettsial antibodies.
Atlanta: National Center for Infectious Diseases; Human ehrlichioses in Brazil: first suspect cases. Braz J Infect Dis. Performance of a commercially available in-clinic ELISA for the detection of antibodies against Anaplasma phagocytophilum, Ehrlichia canis, and Borrelia burgdorferi and Dirofilaria immitis antigen in dogs. Am J Vet Res.
1999, Número 3
Abstract Ehrlichia canis was considered an exclusive canine pathogen and its main vector is ticks of the Rhipicephalus sanguineus complex. Several case studies show that it can also cause pathology in humans, which until now have only been associated with asymptomatic infections and mild to moderate intensity. The aim of this paper is describe the clinical presentation of a severe case of ehrlichiosis, an immuno-competent young man. Present the differential diagnosis of Ehrlichia canis. No results were obtained for serological tests against dengue, hantavirus, HIV, Leptospira, nor on PCR for parainfluenza 1, 2, 3 , adenovirus, influenza A and B , and rhinovirus. This is the first confirmed and described case of E. Dumler, S.
Thiago F. Martins 3. Felipe S. Krawczak 3. Marcelo B.