RESUMO
Rocky Mountain spotted fever is an acute illness caused by Rickettsia rickettsii (R. rickettsii) and is transmitted by the bite of ticks of the genera Dermacentor, Amblyomma and Rhipicephalus. The illness results in a high mortality rate and may be easily confused with other febrile syndromes. In Yucatan State, Mexico, childhood cases with a high mortality have been reported. In this work we report the isolation of a Mexican R. rickettsii strain from a tick egg mass using an alternative method for Rickettsia isolation with 24-well plates. We also identified a potential vector of R. rickettsii in the southeast of Mexico, which is Amblyomma parvum.
RESUMO
The authors describe their work in the Americas in Rickettsia felis cases in humans and the presence of Rickettsia felis in vectors.
Assuntos
Infecções por Rickettsia/epidemiologia , Rickettsia felis , Animais , Humanos , Insetos Vetores , América do Norte/epidemiologia , Infecções por Rickettsia/diagnóstico , América do Sul/epidemiologiaRESUMO
In search for the vector of the recently recognized spotted fever rickettsiosis of the Yucatán, ticks, fleas, and lice were collected from vegetation and dogs in localities where seropositive persons had been found. The arthropods were examined by polymerase chain reaction (PCR) using primers for the genus-specific 17-kDa protein gene followed by restriction fragment length polymorphism (RFLP) and DNA sequencing. Eleven (20%) of 54 pools of Ctenocephalides felis fleas contained DNA of Rickettsia felis. None of 219 Amblyomma cajennense, 474 Rhiphicephalus sanguineus, 258 Boophilus sp. ticks, and 33 Poliplax species lice contained DNA of Rickettsia. The identity of the rickettsial DNA was confirmed as R. felis by PCR/RFLP for the citrate synthase and outer membrane protein A genes and by DNA sequencing. The results indicate that the host of R. felis in Yucatán is C. felis and suggest that the spotted fever rickettsiosis that has infected >5% of the population of the Yucatán and can present as a dengue-like illness is likely to be caused by R. felis.
Assuntos
Insetos Vetores/microbiologia , Infecções por Rickettsia/microbiologia , Rickettsia felis/isolamento & purificação , Sifonápteros/microbiologia , Animais , DNA Bacteriano/isolamento & purificação , Insetos Vetores/classificação , México/epidemiologia , Infecções por Rickettsia/epidemiologia , Rickettsia felis/genética , Sifonápteros/classificaçãoRESUMO
Three patients with fever, exanthem, headache, and central-nervous-system involvement were diagnosed with Rickettsia fells infection by specific PCR of blood or skin and seroconversion to surrogate Rickettsia antigens. Although R. felis's relationship to other Rickettsia species is known and the pathogenic potential of this clade is well documented, R. felis's role as a pathogen has not been fully understood.
Assuntos
Infecções por Rickettsia/patologia , Rickettsia/genética , Adulto , DNA Bacteriano/química , DNA Bacteriano/genética , Feminino , Humanos , Masculino , México , Reação em Cadeia da Polimerase , Infecções por Rickettsia/microbiologia , Análise de Sequência de DNARESUMO
Because of the discovery of a spotted fever group rickettsiosis with signs and symptoms similar to dengue fever in Yucatan, Mexico, immunofluorescence assay (IFA) serology was performed on sera from 390 persons selected from a representative geographic distribution of rural Yucatan to detect antibodies reactive with Rickettsia rickettsii, R. akari, a Thai strain (TT-118) that is most closely related to a rickettsia identified in Amblyomma cajennense ticks in southern Texas, and R. typhi. The IFA antibodies at titers > or = 1:64 against R. akari were detected in 22 (5.6%) of the samples with the expected cross-reactivity against the other antigens of the spotted fever group. Immunoblotting with antigens of R. akari identified antibodies against antigens of spotted fever group lipopolysaccharides and not against rickettsial outer membrane proteins A and B, which contain the species-specific epitopes. A rickettsiosis most likely caused by a relative of R. akari appears to be both prevalent and widely distributed geographically in Yucatan.
Assuntos
Anticorpos Antibacterianos/sangue , Infecções por Rickettsia/epidemiologia , Rickettsia rickettsii/imunologia , Rickettsia typhi/imunologia , Rickettsia/imunologia , Adolescente , Adulto , Idoso , Western Blotting , Reações Cruzadas , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Prevalência , Rickettsia/classificação , Infecções por Rickettsia/microbiologia , Febre Maculosa das Montanhas Rochosas/epidemiologia , Estudos Soroepidemiológicos , Tifo Endêmico Transmitido por Pulgas/epidemiologiaRESUMO
Although Rocky Mountain spotted fever was documented in northern Mexico during the 1940s, spotted fever group (SFG) rickettsioses have subsequently received little attention in Mexico. In this study, sera collected in 1993 from 50 patients from the Mexican states of Yucatan and Jalisco, who were suspected clinically to have dengue fever but had no antibodies to dengue virus, were examined by indirect immunofluorescence for IgM antibodies reactive with Rickettsia rickettsii, R. akari, and R. typhi. Twenty (40%) of the patients' sera contained IgM antibodies to SFG rickettsiae at a titer of 128 or greater. Among five sera reactive only against R. akari, four were from patients in Jalisco where a cluster of cases occurred in June and July. Among five sera reactive only with R. rickettsii, all were from Yucatan patients. Sera of 10 patients contained antibodies reactive with antigens shared by R. rickettsii and R. akari. The clinical signs and symptoms (fever, 100%; myalgia, 95%; headache, 85%; rash, 85%) were similar to those of dengue fever patients identified in this study. However, the incidence of rash was substantially higher than the nondengue, nonrickettsiosis patients. One or more SFG rickettsioses appear to be present in areas of Mexico not previously recognized to harbor these organisms. The etiologic agent or agents are as yet unknown.
Assuntos
Anticorpos Antibacterianos/sangue , Dengue/diagnóstico , Infecções por Rickettsia/diagnóstico , Rickettsia/imunologia , Adolescente , Adulto , Anticorpos Antivirais/sangue , Vírus da Dengue/imunologia , Diagnóstico Diferencial , Surtos de Doenças , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Infecções por Rickettsia/epidemiologia , Rickettsia rickettsii/imunologia , Rickettsia typhi/imunologia , Febre Maculosa das Montanhas Rochosas/diagnóstico , Febre Maculosa das Montanhas Rochosas/epidemiologia , Estações do Ano , Tifo Endêmico Transmitido por Pulgas/diagnóstico , Tifo Endêmico Transmitido por Pulgas/epidemiologiaRESUMO
In order to determine Trypanosoma cruzi infection among mammals in Yucatan, Mexico, 372 animals, both wild and synanthropic including carnivores, marsupials and rodents were studied. Serological studies by indirect haemagglutination (IHA) were carried out to detect antibodies to T. cruzi and a parasitological study was also performed (blood smear and histopathology). Of all the animals tested 18.54% were serologically positive, with a significantly higher frequency among the wild ones (33.33%) compared to the synanthropic ones (17.79%). To determine T. cruzi in positive animals, blood was inoculated into a white mouse (webster type) to prove myocardium colonization. The serological and parasitological positivity of these animals, as well as their behavior in the environment, taken together with the socioeconomic and cultural characteristics of the population, suggest that in Yucatan, Mexico, Canis familiaris, Didelphis marsupialis and Rattus rattus act as a link with the wild cycle.
Assuntos
Doença de Chagas/veterinária , Mamíferos/parasitologia , Animais , Anticorpos Antiprotozoários/sangue , Doença de Chagas/sangue , Doença de Chagas/imunologia , Mamíferos/imunologia , México , Camundongos , Ratos , Trypanosoma cruzi/imunologia , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
The purpose of this study was to determine the frequency of cardiopathy due to Chagas' disease in 36 patients of the cardiology department at the Regional General Hospital O'Horan in Merida, Yucatan. All patients included in the study had cardiac involvement compatible with acute or chronic stages of Chagas' disease. Medical records prepared for each one of the patients included a Chagas' disease targeted clinical history, chest X-ray, electrocardiogram, blood culture and serology using indirect immunofluorescence test. Out of the 36 patients studied, 7 were diagnosed as having Chagas' disease cardiopathy. Grade II cardiomegaly was established in 2 patients while the remaining 5 had grade III cardiomegaly. Conduction abnormalities were established in 6 patients while 2 of these had evidence of necrosis and/or ischemia. Chagas' disease cardiopathy, as our results suggest, is not a rare event in the cardiology ward at the O'Horan Hospital.
Assuntos
Cardiomiopatia Chagásica/epidemiologia , Cardiomiopatia Chagásica/diagnóstico , Doença Crônica , Feminino , Hospitais Gerais , Humanos , México , Pessoa de Meia-IdadeRESUMO
The relationship between abortion and infection by Toxoplasma gondii was analyzed in 100 cases of spontaneous abortions, 51 of which corresponded to single abortions and 49 to cases with a history of repeated abortions. The Sabin-Feldman test was used for the detection of specific antibodies. Parasites were identified and isolated in the aborted material; sections were stained by Hematoxilin-Eosin, processed for indirect immunofluorescence and inoculated into mice. Antibodies to Toxoplasma were detected in 47 percent of the total study population. Positive identification of parasites in the decidua and corionic villae was established in 2 percent of the patients studied. Parasites could only be isolated in one of these patients. Both cases belonged to the group with positive serology and antibody titers of 1:64 and 1:128, and having experienced a single abortion. There was no significant statistical difference with regard to antibody titers between the single abortion and repeated abortion groups. Our results indicate an important causative relationship between toxoplasmosis and abortions in Mérida, Yucatán, México.