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David H. Walker - One of the best experts on this subject based on the ideXlab platform.
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Spotted Fever group Rickettsia in small rodents from areas of low endemicity for Brazilian Spotted Fever in the eastern region of Minas Gerais State, Brazil.
The American journal of tropical medicine and hygiene, 2013Co-Authors: Bruno Silva Milagres, David H. Walker, Marcelo B. Labruna, Cláudio Mafra, Amanda De Freitas Padilha, Carlos Emmanuel Montandon, Renata Nascimento De Freitas, Richard C. Pacheco, Márcio Antônio Moreira GalvãoAbstract:We investigated the humoral immune response against different species of Rickettsia in serum samples from small rodents collected in two areas of a silent focus for Brazilian Spotted Fever in the eastern region of Minas Gerais State, Brazil. Sera samples were analyzed by indirect immunofluorescence assay using antigens from Rickettsia species of the Spotted Fever, ancestral, and transition groups. Titers ≥ 1:64 were considered positive. In Santa Cruz do Escalvado, 94% (30 of 32) of the samples collected from Rattus rattus, 22% (5 of 23) from Nectomys squamipes, and 80% (4 of 5) from Akodon sp., reacted by indirect immunofluorescence assay with Rickettsia antigens of the Spotted Fever group. In the municipality of Pingo D'Água, 84% (26 of 31) of the samples collected from R. rattus, 86% (6 of 7) of the samples from Oryzomys subflavus, 86% (6 of 7) from N. squamipes, and 100% (1 of 1) from Bolomys sp. contained antibodies that reacted with rickettsial antigens of the Spotted Fever group. These results demonstrated the previous exposure of small rodents to Spotted Fever group Rickettsia, suggesting the participation of these animals in the natural history of these rickettsiae in this region.
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first serologic evidence of human Spotted Fever group rickettsiosis in korea
Journal of Clinical Microbiology, 2004Co-Authors: Won-jong Jang, Jonghyun Kim, Kwang Don Jung, Yang Gyu Kim, Seunghyun Lee, Ik Sang Kim, Yeon-joo Choi, Myungsik Choi, David H. Walker, Kyunghee ParkAbstract:To investigate the prevalence of Spotted Fever group rickettsioses in Korea, a serosurvey of Japanese Spotted Fever rickettsiosis in patients with acute febrile illness was conducted with an indirect immunofluorescence assay. Overall, 19.88% of the patients were found to have polyvalent antibody against Rickettsia japonica. This study is the first documentation of Spotted Fever group rickettsiosis in Korea.
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Spotted Fever rickettsiosis in Coronel Fabriciano, Minas Gerais State
Revista da Sociedade Brasileira de Medicina Tropical, 2003Co-Authors: Márcio Antônio Moreira Galvão, Juan P. Olano, Simone Berger Calic, Chequer Buffe Chamone, Gracco Cesarino Filho, Cláudio Lísias Mafra S., David H. WalkerAbstract:We report cases of Spotted Fever rickettsiosis in Coronel Fabriciano Municipality of Minas Gerais State, Brazil. The cases occurred in May and June of 2000. During this period there were two deaths among children from an area named Pedreira in a periurban area of this municipality. In a boy who died with clinical manifestations of Brazilian Spotted Fever, a necropsy revealed the presence of a Spotted Fever group Rickettsia. The serological results confirm the difficulty in the differential diagnosis of patients with symptoms of rickettsial diseases.
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Fatal Spotted Fever Rickettsiosis, Minas Gerais, Brazil
Emerging infectious diseases, 2003Co-Authors: Márcio Antônio Moreira Galvão, Juan P. Olano, J. Stephen Dumler, Cláudio Mafra, Simone Berger Calic, Chequer Buffe Chamone, Gracco Cesarino Filho, David H. WalkerAbstract:The emergence and reemergence of a serious infectious disease are often associated with a high case-fatality rate because of misdiagnosis and inappropriate or delayed treatment. The current reemergence of Spotted Fever rickettsiosis caused by Rickettsia rickettsii in Brazil has resulted in a high proportion of fatal cases. We describe two familial clusters of Brazilian Spotted Fever in the state of Minas Gerais, involving six children 9 months to 15 years of age; five died. Immunohistochemical investigation of tissues obtained at necropsy of a child in each location, Novo Cruzeiro and Coronel Fabriciano municipalities, established the diagnosis by demonstration of disseminated endothelial infection with Spotted Fever group rickettsiae. The diagnosis in the two fatal cases from Coronel Fabriciano and the surviving patient from Novo Cruzeiro was further supported by immunofluorescence serologic tests.
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Hemostatic changes in Rocky Mountain Spotted Fever and Mediterranean Spotted Fever.
American journal of clinical pathology, 1999Co-Authors: M. Tarek Elghetany, David H. WalkerAbstract:Rocky Mountain Spotted Fever and Mediterranean Spotted Fever are rickettsial infections primarily of endothelial cells that normally have a potent anticoagulant function. As a result of endothelial cell infection and injury, the hemostatic system is perturbed and shows changes that vary widely from a minor reduction in the platelet count (frequently) to severe coagulopathies, such as deep venous thrombosis and disseminated intravascular coagulation (rarely). Changes favoring a hypercoagulable state include endothelial injury and release of procoagulant components, activation of the coagulation cascade with thrombin generation, platelet activation, increased antifibrinoly tic factors, consumption of natural anticoagulants, and possibly high levels of coagulation-promoting cytokines. Yet, most studies have been performed on endothelial cell cultures that provide nonphysiologic, reductionistic, experimental conditions. The lack of flow, platelets, and WBCs makes these experiments far from simulating the response of endothelial cells in the human body. Coagulopathies and thrombotic events should be considered as potential complications of severe Rocky Mountain Spotted Fever and Mediterranean Spotted Fever.
Christopher D. Paddock - One of the best experts on this subject based on the ideXlab platform.
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rocky mountain Spotted Fever in mexico past present and future
Lancet Infectious Diseases, 2017Co-Authors: Gerardo Alvarezhernandez, Jesus Felipe Gonzalez Roldan, Nestor Saul Hernandez Milan, Ryan R Lash, Casey Barton Behravesh, Christopher D. PaddockAbstract:Summary Rocky Mountain Spotted Fever, a tick-borne zoonosis caused by Rickettsia rickettsii , is among the most lethal of all infectious diseases in the Americas. In Mexico, the disease was first described during the early 1940s by scientists who carefully documented specific environmental determinants responsible for devastating outbreaks in several communities in the states of Sinaloa, Sonora, Durango, and Coahuila. These investigators also described the pivotal roles of domesticated dogs and Rhipicephalus sanguineus sensu lato (brown dog ticks) as drivers of epidemic levels of Rocky Mountain Spotted Fever. After several decades of quiescence, the disease re-emerged in Sonora and Baja California during the early 21st century, driven by the same environmental circumstances that perpetuated outbreaks in Mexico during the 1940s. This Review explores the history of Rocky Mountain Spotted Fever in Mexico, current epidemiology, and the multiple clinical, economic, and social challenges that must be considered in the control and prevention of this life-threatening illness.
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Rocky Mountain Spotted Fever in Argentina.
The American journal of tropical medicine and hygiene, 2008Co-Authors: Christopher D. Paddock, Susana Fernandez, Gustavo A. Echenique, John W. Sumner, Will K. Reeves, Sherif R. Zaki, Carlos E. RemondeguiAbstract:We describe the first molecular confirmation of Rickettsia rickettsii, the cause of Rocky Mountain Spotted Fever (RMSF), from a tick vector, Amblyomma cajennense, and from a cluster of fatal Spotted Fever cases in Argentina. Questing A. cajennense ticks were collected at or near sites of presumed or confirmed cases of Spotted Fever rickettsiosis in Jujuy Province and evaluated by polymerase chain reaction assays for Spotted Fever group rickettsiae. DNA of R. rickettsii was amplified from a pool of A. cajennense ticks and from tissues of one of four patients who died during 2003-2004 after illnesses characterized by high Fever, severe headache, myalgias, and petechial rash. The diagnosis of Spotted Fever rickettsiosis was confirmed in the other patients by indirect immunofluorescence antibody and immunohistochemical staining techniques. These findings show the existence of RMSF in Argentina and emphasize the need for clinicians throughout the Americas to consider RMSF in patients with febrile rash illnesses.
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rocky mountain Spotted Fever panama
Emerging Infectious Diseases, 2007Co-Authors: Dora Estripeaut, Christopher D. Paddock, Sherif R. Zaki, Gregory A. Dasch, Maria Gabriela Aramburu, Xavier Saezllorens, Herbert A Thompson, Marina E. EremeevaAbstract:We describe a fatal pediatric case of Rocky Mountain Spotted Fever in Panama, the first, to our knowledge, since the 1950s. Diagnosis was established by immunohistochemistry, PCR, and isolation of Rickettsia rickettsii from postmortem tissues. Molecular typing demonstrated strong relatedness of the isolate to strains of R. rickettsii from Central and South America.
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Rocky Mountain Spotted Fever from an unexpected tick vector in Arizona.
The New England journal of medicine, 2005Co-Authors: Linda J. Demma, Christopher D. Paddock, Marc S. Traeger, William L. Nicholson, Dianna M. Blau, Marina E. Eremeeva, Gregory A. Dasch, Michael Levin, Joseph Singleton, Sherif R. ZakiAbstract:background Rocky Mountain Spotted Fever is a life-threatening, tick-borne disease caused by Rickettsia rickettsii . This disease is rarely reported in Arizona, and the principal vectors, Dermacentor species ticks, are uncommon in the state. From 2002 through 2004, a focus of Rocky Mountain Spotted Fever was investigated in rural eastern Arizona. methods We obtained blood and tissue specimens from patients with suspected Rocky Mountain Spotted Fever and ticks from patients’ homesites. Serologic, molecular, immunohistochemical, and culture assays were performed to identify the causative agent. On the basis of specific laboratory criteria, patients were classified as having confirmed or probable Rocky Mountain Spotted Fever infection. results A total of 16 patients with Rocky Mountain Spotted Fever infection (11 with confirmed and 5 with probable infection) were identified. Of these patients, 13 (81 percent) were children 12 years of age or younger, 15 (94 percent) were hospitalized, and 2 (12 percent) died. Dense populations of Rhipicephalus sanguineus ticks were found on dogs and in the yards of patients’ homesites. All patients with confirmed Rocky Mountain Spotted Fever had contact with tick-infested dogs, and four had a reported history of tick bite preceding the illness. R. rickettsii DNA was detected in nonengorged R. sanguineus ticks collected at one home, and R. rickettsii isolates were cultured from these ticks. conclusions This investigation documents the presence of Rocky Mountain Spotted Fever in eastern Arizona, with common brown dog ticks ( R. sanguineus ) implicated as a vector of R. rickettsii . The broad distribution of this common tick raises concern about its potential to transmit R. rickettsii in other settings.
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Rocky Mountain Spotted Fever: a clinician's dilemma.
Archives of internal medicine, 2003Co-Authors: Edwin J. Masters, Gary S. Olson, Scott J. Weiner, Christopher D. PaddockAbstract:Rocky Mountain Spotted Fever is still the most lethal tick-vectored illness in the United States. We examine the dilemmas facing the clinician who is evaluating the patient with possible Rocky Mountain Spotted Fever, with particular attention to the following 8 pitfalls in diagnosis and treatment: (1) waiting for a petechial rash to develop before diagnosis; (2) misdiagnosing as gastroenteritis; (3) discounting a diagnosis when there is no history of a tick bite; (4) using an inappropriate geographic exclusion; (5) using an inappropriate seasonal exclusion; (6) failing to treat on clinical suspicion; (7) failing to elicit an appropriate history; and (8) failing to treat with doxycycline. Early diagnosis and proper treatment save lives.
Gregory A. Dasch - One of the best experts on this subject based on the ideXlab platform.
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rocky mountain Spotted Fever panama
Emerging Infectious Diseases, 2007Co-Authors: Dora Estripeaut, Christopher D. Paddock, Sherif R. Zaki, Gregory A. Dasch, Maria Gabriela Aramburu, Xavier Saezllorens, Herbert A Thompson, Marina E. EremeevaAbstract:We describe a fatal pediatric case of Rocky Mountain Spotted Fever in Panama, the first, to our knowledge, since the 1950s. Diagnosis was established by immunohistochemistry, PCR, and isolation of Rickettsia rickettsii from postmortem tissues. Molecular typing demonstrated strong relatedness of the isolate to strains of R. rickettsii from Central and South America.
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Rocky Mountain Spotted Fever from an unexpected tick vector in Arizona.
The New England journal of medicine, 2005Co-Authors: Linda J. Demma, Christopher D. Paddock, Marc S. Traeger, William L. Nicholson, Dianna M. Blau, Marina E. Eremeeva, Gregory A. Dasch, Michael Levin, Joseph Singleton, Sherif R. ZakiAbstract:background Rocky Mountain Spotted Fever is a life-threatening, tick-borne disease caused by Rickettsia rickettsii . This disease is rarely reported in Arizona, and the principal vectors, Dermacentor species ticks, are uncommon in the state. From 2002 through 2004, a focus of Rocky Mountain Spotted Fever was investigated in rural eastern Arizona. methods We obtained blood and tissue specimens from patients with suspected Rocky Mountain Spotted Fever and ticks from patients’ homesites. Serologic, molecular, immunohistochemical, and culture assays were performed to identify the causative agent. On the basis of specific laboratory criteria, patients were classified as having confirmed or probable Rocky Mountain Spotted Fever infection. results A total of 16 patients with Rocky Mountain Spotted Fever infection (11 with confirmed and 5 with probable infection) were identified. Of these patients, 13 (81 percent) were children 12 years of age or younger, 15 (94 percent) were hospitalized, and 2 (12 percent) died. Dense populations of Rhipicephalus sanguineus ticks were found on dogs and in the yards of patients’ homesites. All patients with confirmed Rocky Mountain Spotted Fever had contact with tick-infested dogs, and four had a reported history of tick bite preceding the illness. R. rickettsii DNA was detected in nonengorged R. sanguineus ticks collected at one home, and R. rickettsii isolates were cultured from these ticks. conclusions This investigation documents the presence of Rocky Mountain Spotted Fever in eastern Arizona, with common brown dog ticks ( R. sanguineus ) implicated as a vector of R. rickettsii . The broad distribution of this common tick raises concern about its potential to transmit R. rickettsii in other settings.
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First Cases of Spotted Fever Group Rickettsiosis in Thailand
The American journal of tropical medicine and hygiene, 1994Co-Authors: Thira Sirisanthana, Virat Pinyopornpanit, Virat Sirisanthana, Daniel Strickman, Daryl J. Kelly, Gregory A. DaschAbstract:Abstract The first three cases of Spotted Fever group rickettsiosis from Thailand are reported. The patients presented with Fever, headache, lymphadenopathy, and petechial maculopapular rash. One patient also had an eschar and overt evidence of confusion. An indirect fluorescent antibody test, an indirect immunoperoxidase test, and an enzyme-linked immunosorbent assay demonstrated a broad, strong reactions of the sera of the patients with Spotted Fever group rickettsia antigens of many species, but not with antigens of typhus or scrub typhus rickettsiae. All three patients responded to treatment with a single dose of doxycycline.
Didier Raoult - One of the best experts on this subject based on the ideXlab platform.
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mediterranean Spotted Fever
Infectious Disease Clinics of North America, 2008Co-Authors: Clarisse Rovery, Didier RaoultAbstract:Rickettsial disease has recently undergone an important evolution, particularly in the field of molecular genetics. This development includes Mediterranean Spotted Fever (MSF), a tick-borne disease caused by Rickettsia conorii . Important changes have occurred in ecologic and epidemiologic comprehension of the disease, and in the occurrence of severe forms. However, many questions still remain, including the identity of the real vector and reservoir of R conorii , and whether other risk factors exist for a severe form of MSF.
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Fatal case of Israeli Spotted Fever after Mediterranean cruise.
Emerging infectious diseases, 2008Co-Authors: Noémie Boillat, Didier Raoult, Blaise Genton, Valérie D'acremont, Gilbert GreubAbstract:To the Editor: Israeli Spotted Fever (ISF) is caused by Rickettsia conorii subsp. israelensis. This recently described subspecies is genetically close to R. conorii subsp. conorii, the agent of Mediterranean Spotted Fever (MSF) (1,2). ISF is likely transmitted by the dog tick Rhipicephalus sanguineus (3). This tick, which is also the vector of R. conorii subsp. conorii, has low affinity for hosts other than dogs. Therefore, like MSF, cases of ISF will likely be sporadic (4,5). ISF was first reported in Israel (1) and was also recently described in Portugal and Italy (6–8). The clinical manifestations of ISF are similar to those of other Spotted Fever group infections, but an inoculation eschar is rarely observed and a history of tick exposure is not always present (4–6,9). The incubation period is ≈7–8 days after the tick bite (4).
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Serosurvey among Mediterranean Spotted Fever patients of a new Spotted Fever group rickettsial strain (Bar29)
European journal of epidemiology, 2003Co-Authors: Neus Cardeñosa, Ferran Segura, Didier RaoultAbstract:Mediterranean Spotted Fever is an endemic disease in Catalonia, Spain. A new Spotted Fever group (SFG) rickettsial strain (Bar29) of unknown pathogenicity for humans was isolated by our group, in 1996, from the dog brown tick, Rhipicephalus sanguineus. Interestingly, Rickettsia conorii was not isolated in this study. The aim of the present study was to assess the possible pathogenic role of the Bar29 strain. To this purpose, serum samples from 15 patients with Mediterranean Spotted Fever were obtained and tested by immunofluorescence for antibodies against four related rickettsial strains (R. conorii, R. africae, R. massiliae, and Bar29). Eight of the studied sera reacted at high titers with only R. conorii and Bar29 antigens. For five of the eight sera, the titers against Bar29 were clearly higher than for R. conorii. Four of these sera were also studied by Western blot immunoassay to confirm a specific response. Two of these sera reacted with the high-molecular-mass specific proteins of Bar29 as well as with the low-molecular-mass region (LPS antigen) whereas their reactions with R. conorii were located only on bands of the LPS. This specific response would support the possible pathogenic role of the Bar29 strain for humans. According to this finding, Spotted Fever caused by R. conorii and rickettsial strain Bar29 may be present in our area. The epidemiological implications of Spotted Fever caused by R. conorii and by rickettsial strain Bar29 in the Catalonia deserve further studies with isolation and characterization of more rickettsial strains.
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Studies of a "new" rickettsiosis "Astrakhan" Spotted Fever.
European journal of epidemiology, 1991Co-Authors: Irina Tarasevich, V. A. Makarova, N. F. Fetisova, A. V. Stepanov, E. D. Miskarova, Didier RaoultAbstract:The acute febrile disease with characteristic rash seen in Astrakhan region and named as "viral exanthema of unknown etiology" was proved to be a Spotted Fever group rickettsiosis. Serological examination of humans from endemic areas by complement fixation test revealed antibodies to R. conorii, R. akari and strains Netsvetaev and AR-74 of R. sibirica in titres from 20 to 640 in sera from ill persons. Of 429 sera from healthy persons, 5.1% were serologically positive in a titre of 20-40. The presence of Spotted Fever group rickettsiae was detected in 8 of 104 Rhipicephalus sanguineus ticks removed from dogs and tested by haemocyte test with Gimenez staining and indirect immunofluorescence technique. Attempts at isolation of rickettsiae in guinea pigs and cell cultures resulted in appearance of specific Spotted Fever group rickettsiae antibodies in guinea pigs (4 of 8 samples examined were positive) and detection of rickettsiae by immunofluorescence technique in cell cultures (in 2 of 12 samples tested).
Márcio Antônio Moreira Galvão - One of the best experts on this subject based on the ideXlab platform.
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Spotted Fever group Rickettsia in small rodents from areas of low endemicity for Brazilian Spotted Fever in the eastern region of Minas Gerais State, Brazil.
The American journal of tropical medicine and hygiene, 2013Co-Authors: Bruno Silva Milagres, David H. Walker, Marcelo B. Labruna, Cláudio Mafra, Amanda De Freitas Padilha, Carlos Emmanuel Montandon, Renata Nascimento De Freitas, Richard C. Pacheco, Márcio Antônio Moreira GalvãoAbstract:We investigated the humoral immune response against different species of Rickettsia in serum samples from small rodents collected in two areas of a silent focus for Brazilian Spotted Fever in the eastern region of Minas Gerais State, Brazil. Sera samples were analyzed by indirect immunofluorescence assay using antigens from Rickettsia species of the Spotted Fever, ancestral, and transition groups. Titers ≥ 1:64 were considered positive. In Santa Cruz do Escalvado, 94% (30 of 32) of the samples collected from Rattus rattus, 22% (5 of 23) from Nectomys squamipes, and 80% (4 of 5) from Akodon sp., reacted by indirect immunofluorescence assay with Rickettsia antigens of the Spotted Fever group. In the municipality of Pingo D'Água, 84% (26 of 31) of the samples collected from R. rattus, 86% (6 of 7) of the samples from Oryzomys subflavus, 86% (6 of 7) from N. squamipes, and 100% (1 of 1) from Bolomys sp. contained antibodies that reacted with rickettsial antigens of the Spotted Fever group. These results demonstrated the previous exposure of small rodents to Spotted Fever group Rickettsia, suggesting the participation of these animals in the natural history of these rickettsiae in this region.
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Spotted Fever rickettsiosis in Coronel Fabriciano, Minas Gerais State
Revista da Sociedade Brasileira de Medicina Tropical, 2003Co-Authors: Márcio Antônio Moreira Galvão, Juan P. Olano, Simone Berger Calic, Chequer Buffe Chamone, Gracco Cesarino Filho, Cláudio Lísias Mafra S., David H. WalkerAbstract:We report cases of Spotted Fever rickettsiosis in Coronel Fabriciano Municipality of Minas Gerais State, Brazil. The cases occurred in May and June of 2000. During this period there were two deaths among children from an area named Pedreira in a periurban area of this municipality. In a boy who died with clinical manifestations of Brazilian Spotted Fever, a necropsy revealed the presence of a Spotted Fever group Rickettsia. The serological results confirm the difficulty in the differential diagnosis of patients with symptoms of rickettsial diseases.
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Fatal Spotted Fever Rickettsiosis, Minas Gerais, Brazil
Emerging infectious diseases, 2003Co-Authors: Márcio Antônio Moreira Galvão, Juan P. Olano, J. Stephen Dumler, Cláudio Mafra, Simone Berger Calic, Chequer Buffe Chamone, Gracco Cesarino Filho, David H. WalkerAbstract:The emergence and reemergence of a serious infectious disease are often associated with a high case-fatality rate because of misdiagnosis and inappropriate or delayed treatment. The current reemergence of Spotted Fever rickettsiosis caused by Rickettsia rickettsii in Brazil has resulted in a high proportion of fatal cases. We describe two familial clusters of Brazilian Spotted Fever in the state of Minas Gerais, involving six children 9 months to 15 years of age; five died. Immunohistochemical investigation of tissues obtained at necropsy of a child in each location, Novo Cruzeiro and Coronel Fabriciano municipalities, established the diagnosis by demonstration of disseminated endothelial infection with Spotted Fever group rickettsiae. The diagnosis in the two fatal cases from Coronel Fabriciano and the surviving patient from Novo Cruzeiro was further supported by immunofluorescence serologic tests.
