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Production and characterization of monoclonal antibodies to Rickettsia rickettsii.

Five mouse ascitic fluids (MAFs) containing monoclonal antibody to Rickettsia rickettsii were produced from three original fusions by murine hybridoma technology. The five MAFs were fractionated and purified; each contained monoclonal antibody of the immunoglobulin G2a subclass. Each monoclonal antibody-containing MAF was titrated by indirect immunofluorescence against three R. rickettsii isolates from humans and four other spotted fever group rickettsiae. Each MAF was also titrated in the complement fixation, latex agglutination, microagglutination, and indirect hemagglutination tests. Two of…

Endemicity of spotted fever group rickettsiae in Connecticut.

To compare rickettsial infectivity and seropositivity rates against spotted fever group (SFG) rickettsiae, ticks and wild mammals were collected from three areas where Rickettsia rickettsii was thought to be enzootic in Connecticut during 1978-1979, and from four additional sites (with no reported human cases) between 1976 and 1979. Of the 1,001 Dermacentor variabilis examined by the hemolymph test, 59 (5.9%) contained rickettsia-like organisms; direct immunofluorescence tests verified the presence of SFT rickettsiae in 14 specimens. Prevalence of rickettsiae-infected ticks at Newtown, an area…

Proteins of typhus and spotted fever group rickettsiae.

Purified radioactive rickettsiae were obtained from irradiated and cycloheximide-inhibited L cells, and their proteins were analyzed by polyacrylamide gel electrophoresis. Rickettsial species could be distinguished by comparing the relative mobilities of constituent proteins after migration of two differentially labeled preparations in a single gel. Distinct differences were observed in gel patterns of rickettsiae from the typhus and spotted fever groups, as well as with different species within a group. Rickettsial organisms causing murine and epidemic typhus were clearly distinguished, as we…

Plaque assay of rickettsiae in a mammalian cell line.

Clear-cut and repeatable plaque assays were obtained for three rickettsiae of the spotted fever group (Rickettsia rickettsi, R. conori, and R. montana) in Vero cells used in a manner similar to that for arboviruses. In addition, three typhus group agents (R. typhi, R. canada, R. prowazeki) induced plaques in these cells. In preliminary tests Coxiella burneti (Nine Mile strain) failed to produce plaques. Comparable results were obtained in plastic flasks and plastic culture trays incubated in ambient air with or without addition of N-2-hydroxyethyl-piperazine-N'-2-ethanesulfinic acid buffer. La…

High prevalence of "Candidatus Rickettsia andeanae" and apparent exclusion of Rickettsia parkeri in adult Amblyomma maculatum (Acari: Ixodidae) from Kansas and Oklahoma.

Amblyomma maculatum (the Gulf Coast tick), an aggressive, human-biting, Nearctic and Neotropical tick, is the principal vector of Rickettsia parkeri in the United States. This pathogenic spotted fever group Rickettsia species has been identified in 8-52% of questing adult Gulf Coast ticks in the southeastern United States. To our knowledge, R. parkeri has not been reported previously from adult specimens of A. maculatum collected in Kansas or Oklahoma. A total of 216 adult A. maculatum ticks were collected from 18 counties in Kansas and Oklahoma during 2011-2014 and evaluated by molecular meth…

High rates of Rickettsia parkeri infection in Gulf Coast ticks (Amblyomma maculatum) and identification of "Candidatus Rickettsia andeanae" from Fairfax County, Virginia.

The Gulf Coast tick, Amblyomma maculatum, is a vector of Rickettsia parkeri, a recently identified human pathogen that causes a disease with clinical symptoms that resemble a mild form of Rocky Mountain spotted fever. Because the prevalence of R. parkeri infection in geographically distinct populations of A. maculatum is not fully understood, A. maculatum specimens collected as part of a tick and pathogen surveillance system in Fairfax County, Virginia, were screened to determine pathogen infection rates. Overall, R. parkeri was found in 41.4% of the A. maculatum that were screened. Additional…

Clinical case of spotted fever group rickettsiae.

We report a Astrakhan ricketsiosis fever in woman who came from Astrakhan. On admission she had fever, intoxication syndrome, exanthema. In complex examination of blood serum by ELISA were reveled IgM and IgG to Rickettsia conorii on the 15th day of the disease.

Evidence of exposure to Rickettsia felis in Australian patients.

Rickettsia felis is an emerging zoonosis, causing flea-borne spotted fever (FBSF). Serological diagnosis is typically confounded by cross-reactivity with typhus group rickettsiae and prior to the development of specific serological methods, cases of FBSF in Australia were misdiagnosed. Patient sera tested between August 2010 and December 2013 and known to be seropositive to R. typhi by immunofluorescence antibody testing (IFAT) were subsequently retested against R. felis using an R. felis-specific IFAT. Sera of 49 patients were of a sufficient quality to be included in re-analysis. A classific…

Strategies for detecting rickettsiae and diagnosing rickettsial diseases.

Rickettsial diseases and scrub typhus constitute a group of the oldest known vector-borne diseases. The cosmopolitan distribution of the vectors that transmit rickettsiae and orientiae leads to a worldwide prevalence of these diseases. Despite their significant historical status, detection and diagnosis of these diseases are still evolving today. Serological methods remain among the most prevalent techniques used for the detection/diagnosis of rickettsial diseases and scrub typhus. Molecular techniques have been instrumental in increasing the sensitivity/specificity of diagnosis, identifying n…

Serosurveillance of Orientia tsutsugamushi and Rickettsia typhi in Bangladesh.

Scrub and murine typhus infections are under-diagnosed causes of febrile illness across the tropics, and it is not known how common they are in Bangladesh. We conducted a prospective seroepidemiologic survey across six major teaching hospitals in Bangladesh by using an IgM enzyme-linked immunosorbent assay. Results indicated recent exposure (287 of 1,209, 23.7% seropositive for Orientia tsutsugamushi and 805 of 1,209, 66.6% seropositive for Rickettsia typhi). Seropositive rates were different in each region. However, there was no geographic clustering of seropositive results for both organisms…

Molecular detection of Rickettsia typhi in cats and fleas.

BACKGROUND: Rickettsiatyphi is the etiological agent of murine typhus (MT), a disease transmitted by two cycles: rat-flea-rat, and peridomestic cycle. Murine typhus is often misdiagnosed and underreported. A correct diagnosis is important because MT can cause severe illness and death. Our previous seroprevalence results pointed to presence of human R. typhi infection in our region; however, no clinical case has been reported. Although cats have been related to MT, no naturally infected cat has been described. The aim of the study is to confirm the existence of R. typhi in our location analyzin…

Рикитцзя в Заливе тикает, Арканзас, США.

Для того чтобы определить причины пятна лихорадки на юге Соединенных Штатов, мы проверили клещи (Amblyomma maculatum), собранные в Арканзасе, на рикетсиа. Из проверенных клещей 30% имели ампликоны PCR, соответствующие Рикитсии Паркери или Кандидату Рикеттсии.

Совпадение в аннотации оригинала
To determine the cause of spotted fever cases in the southern United States, we screened Gulf Coast ticks (Amblyomma maculatum) collected in Arkansas for rickettsiae. Of the screened ticks, 30% had PCR amplicons consistent with Rickettsia parkeri or Candidatus Rickettsia amblyommii.

Spotted fever group rickettsiae in ticks, Morocco.

A total of 370 ticks, encompassing 7 species from 4 genera, were collected during 2002-2006 from domestic animals and vegetation in the Taza region of northeastern Morocco. Rickettsial DNA was identified in 101 ticks (27%) by sequencing PCR products of fragments of the citrate synthase and outer membrane protein genes of Rickettsia spp. Seven rickettsiae of the spotted fever group were identified, including 4 pathogens: R. aeschlimannii in Hyalomma marginatum marginatum, R. massiliae in Rhipicephalus sanguineus, R. slovaca in Dermacentor marginatus, and R. monacensis in Ixodes ricinus. Two sus…

Rickettsia: an unusual cause of sepsis in the emergency department.

Mediterranean spotted fever (caused by Rickettsia conorii) is one of the tick-borne rickettsioses. It is prevalent in southern Europe, Africa and central Asia and may also be seen in travellers returning from these areas. It presents with various non-specific symptoms, including fever, maculopapular rash, headache, myalgia or diarrhoea and vomiting. A visible eschar at the site of the tick bite is characteristic but not present in all cases. There is no test that reliably confirms the disease in its early stages and diagnosis is often made on clinical grounds. Delay in diagnosis and in providi…

Investigation of Rickettsia conorii antibodies in the Antalya area.

Mediterranean spotted fever, caused by Rickettsia conorii, is a tick-borne infection. Serum samples for screening R. conorii antibodies of professionally exposed persons in the Antalya region, on the Mediterranean coast of Turkey, were analyzed. R. conorii IgG antibodies were detected in 13 of 98 (13.3%) serum samples. Mediterranean spotted fever antibodies were found to be positive in 9.4% of the men and 15.2% of the women (a total of 13 cases). Only three cases had a history of fever and rash.