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PubMedDate not supplied

[Chemotherapy of experimental rickettsial infection under the influence of small doses of radiation].

Radiation is of particular importance among a lot of environment factors dangerous for human health, including the effect of small dozes of radiation. State of rickettsial infection under the influence of small dozes of radiation and under administration of immunostimulator Imunal and antibiotic doxycyclin has been studied. Researches were conducted on guinea pigs, using the experimental rickettsial infection. Researches have shown that the use of immunostimulator Imunal and antibiotic doxycyclin had positive effect on the immunity indices of the experimental rickettsial infection in animals in the conditions of influence of small dozes of radiation.

Animals↗
PubMedDate not supplied

Bacillary angiomatosis: microbiology, histopathology, clinical presentation, diagnosis and management.

Bacillary angiomatosis is known to be caused by a rickettsial organism; Rochalimaea henselae. This causative agent has been compared with different microorganisms and clinical conditions that appear in similar settings but that have been clearly differentiated from them; e.i. Cat-scratch disease (Afipia felis), Bartonella bacilliformis, other Rochalimaea sp., Kaposi;s sarcoma, Lobular capillary hemangioma, Angiosarcoma, and Epithelioid hemangioma. Clinically the bacillary angiomatosis (BA) skin lesions vary from a single lesion to thousands. The cutaneous lesion appears as a bright-red round papule, subcutaneous nodule, or as a cellulitic plaque. When the lesion is biopsied it tends to blanch-out, bleed, and cause pain. The patient might present with signs and symptoms of chills, headaches, fever, malaise, and anorexia with or without weight loss. The extracutaneous lesions found in BA tend to be from multiple organs affecting from the oral lesions to anal mucosal lesions to widespread visceral lesions. The sites of preferences for BA lesion manifestation tend to be the liver, spleen, lymph nodes, and bone. To diagnose bacillary angiomatosis the physician should prepare a differential diagnosis based primarily on its histopathological and clinical characteristics. To confirm the results from the stain, electron microscopy can identify the bacillus and pin-point the diagnosis of bacillary angiomatosis. The lesions presented by BA respond well to therapy with erythromycin 500mg four times daily for a duration of 2 weeks to 2 months. In case of intolerance to erythromycin the second line of drug that successfully treats the BA bacillus is doxycycline. If relapses of the BA lesion recur, then a prolonged antibiotic therapy is necessary and in AIDS patients the duration may be extended as life-long suppressive therapy.

Angiomatosis, Bacillary↗
PubMed1995

[A case of tsutsugamushi disease which occurred in south western Shikoku].

We report a case of tsutsugamushi disease found in south western Shikoku. A 64-year-old male who lived in Towa Village in Kochi, developed a fever and headache on April 6, 1994, and was admitted to Uwajima City Hospital on April 15, with a ten-day history of illness. He had an eschar on the right anterior side of the breast and an enlargement of the right axillary lymph node, without a rash. Laboratory data showed mild liver injury and atypical lymphocytes with 6% in peripheral blood. After his blood was drawn for rickettsial isolation, the minocycline was administered. His symptoms improved rapidly and was discharged in good condition. We successfully isolated the causative agent, Rickettsia tsutugamushi, and designated it as the Shiba strain. High antibody titer against the Kato, Karp and Gilliam strains was detected in serum on admission and increased during the course of the disease. In Shikoku, tsutsugamushi disease is rare and only 13 cases were reported during last ten years. Especially in south western district of Shikoku, there have been no case reported since 1960. This case is important epidemiologically and suggests that we should pay attention to this disease.

Anti-Bacterial Agents↗
PubMed1991

Pathogenesis of rickettsial infections emphasis on Q fever.

The underlying mechanisms at the organismic, cellular and molecular levels that account for rickettsial pathogenesis are beginning to be revealed. In the case of Coxiella burnetii infection, relatively recent genetic and biochemical data, as well as drug susceptibility studies, indicate a correlation between isolate type and clinical disease--chronic or short-term acute. The use of cultured cells as model host systems has revealed that, indeed, different isolates from the major classified strains of C. burnetii cause different host cell responses. Use of this and other models (guinea pigs, mice) have revealed other characteristics and properties of the rickettsiae and the infected hosts and host cells that may account, in part, for acute disease and persistent infection culminating in chronic disease. The virulence factors involved apparently include the agent's surface lipopolysaccharide; other unidentified factors have not been excluded. Molecular cloning will play a major role in elucidating the roles of these factors and in identifying other virulence determinants.

Acute Disease↗
PubMed2003

From genes to proteins: in vitro expression of rickettsial proteins.

The availability of the complete genome sequences of several organisms allows the comparative analysis of genomes, a branch of bioinformatics known as genomics. With this approach, much can be learned about the biology of organisms that are difficult to culture, even when few, if any, of their proteins have been isolated and studied directly. We have focused our interest on Rickettsia conorii, an obligate intracellular bacterium responsible for Mediterranean spotted fever, a disease endemic in southern Europe. While bioinformatic annotation of the complete genome of this bacteria has allowed identification of 1,374 genes, a large number of them remain functionally uncharacterized. The final goal of many experiments in molecular biology is to use biological systems to synthesize the protein encoded by the gene being studied. Because three-dimensional structures are more resilient to evolution and change than amino acid sequences, structure determination of some open reading frames should also exhibit structural similarity to previously described protein families. We have thus initiated a systematic expression and structure determination program for the proteins encoded by rickettsial genes of interest. We have cloned different genes of R. conorii by recombinational cloning (GATEWAY), Invitrogen) a method that uses in vitro site-specific recombination to accomplish a directional cloning of PCR products and the subsequent automatic subcloning of the DNA segment into new vector backbones at high efficiency. The constructions in p-Dest17 yielded several clones able to express recombinant proteins with a C-terminal histidine tag. Expression of corresponding proteins was then performed using a cell-free protein expression system (Rapid Translation System, RTS, Roche Diagnostics). The recombinational cloning approach coupled to RTS provides an approach to rapid optimization of protein expression and is very useful to express rickettsial proteins. Moreover, this system is able to overcome some of the limitations encountered with rickettsial proteins highly toxic for E. coli or insect cells.

Bacterial Proteins↗
PubMed1979

[Boutonneuse fever in tourists as a model for clinical diagnosis of rickettsioses (author's transl)].

Case histories of boutonneuse fever are described in order to exemplify major characteristics of most rickettsioses: recent travel history, feverish illness with severe headache, skin eruptions and histological findings. Up-to-date informations concerning the epidemiologic situation of typhus, scrub typhus and Rocky Mountain spotted fever are given. The characteristics of Q fever and the possibility of rickettsial laboratory infections are pointed out.

Adult↗
PubMed1977

[Pathologo-anatomic and experimental study of the morphology of Q-fever].

The article presents a survey of the literature containing reports on lesions of some human organs in Q-fever and on a possible role of the pathogene--Rickettsia burnetii in the development of these lesions. Pathoanatomical findings were compared with those of the experimental investigations of the Q-rickettsial infectious process. The literature data and the author's own investigations confirm the capability of Rickettsia burnetii of parasitizing in cells of the reticulo-endothelial system. This is an important factor in the pathogenicity of this causative agent and lies at the root of the pathogenesis of Q-rickettsial infection.

Animals↗
PubMed2005

Serologic survey of select infectious diseases in coyotes and raccoons in Nebraska.

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%).

Animals↗
PubMed1992

Murine typhus: forgotten but not gone.

An occasional patient presents the classical symptoms of a disease that has become uncommon. Typhus is an example of such a disease, since it is now well contained through control of its rodent reservoir. It is readily treated with tetracycline or one of its long-acting analogues, doxycycline or minocycline. Because typhus is infrequently encountered, the physician may not initially include it in his differential diagnosis. Our case serves as a remainder that with the increasingly frequent movement of persons from one geographic area to another, the uncommon rickettsial infection, murine typhus, should continue to be in the differential of a febrile patient. Furthermore, our case underscores the importance of including typhus in the differential of typhoid fever.

Acute Disease↗
PubMed2005

Western gray squirrel (Rodentia: Sciuridae): a primary reservoir host of Borrelia burgdorferi in Californian oak woodlands?

In California, dense woodlands have been recognized as important biotopes where humans are exposed to the nymphal stage of the western blacklegged tick, Ixodes pacificus Cooley & Kohls, the primary vector of the Lyme disease spirochete Borrelia burgdorferi sensu stricto (s.s.), in the far-western United States. To identify the principal reservoir host(s) of this spirochete, and of closely related spirochetes in the B. burgdorferi sensu lato (s.l.) complex, in dense woodlands in Mendocino County, California, approximately 50 species of birds and mammals, including wood rats and kangaroo rats, were evaluated as potential hosts for vector ticks and borreliae in 2002 and 2003. Although polymerase chain reaction (PCR) and sequencing analyses revealed that many vertebrate species had been exposed to one or more members of the B. burgdorferi s.l. spirochetal complex, only the western gray squirrel, Sciurus griseus, fulfilled the major criteria for a reservoir host of B. burgdorferi s.s. Ear-punch biopsies from eight of 10 squirrels collected from five separate woodlands were PCR-positive for B. burgdorferi s.s., 47% of I. pacificus larvae (n = 64) and 31% of nymphs (n = 49) removed from squirrels contained B. burgdorferi s.l., and the engorgement status of I. pacificus larvae was associated positively with acquisition of spirochetes. Overall, 83 and 100% of the amplicons sequenced from PCR-positive I. pacificus larvae and nymphs, respectively, were identified as B. burgdorferi s.s, Among the five remaining positive I. pacificus larvae, three contained B. bissettii and two had uncharacterized B. burgdorferi s.l. Borrelia burgdorferi s.s. was detected in one of five larvae and zero of two nymphs of the Pacific Coast tick, Dermacentor occidentalis Marx, that likewise had been removed from squirrels. The rickettsial agent of human anaplasmosis, Anaplasma phagocytophilum, was detected in the blood or ear biopsies of two squirrels and in one (1.6%) of 64 I. pacificus larvae and two (4.1%) of 49 nymphs obtained from squirrels. The one rickettsial-positive larva was coinfected with B. burgdorferi s.s. The apparently high reservoir potential of S. griseus for B. burgdorferi s.s., plus the fact that the geographic distribution of this squirrel coincides well with that of most reported human cases of Lyme disease in this region, indicated that it may be essential for maintaining foci of B. burgdorferi s.s. in certain types of woodlands. The findings with respect to A. phagocytophilum, although of less certain significance, suggest that S. griseus could serve as a secondary host of this rickettsia.

Animals↗
PubMed2006

Widened coronary arteries in a feverish child.

A 3-year-old girl with fever of unknown origin after a visit to Surinam was seen at our hospital. Signs and symptoms were indicative of either Kawasaki syndrome or an acute viral or (atypical) bacterial illness. No cardiac abnormalities were noted at echocardiography. She was treated with intravenous immunoglobulin and clarithromycin and made a quick recovery. Serologically, the diagnosis of murine typhus was made; a flea-borne rickettsiosis caused by Rickettsia typhi. A follow-up echocardiography 1 week later showed a dilated left coronary artery, which was normal again 4 weeks later. We suggest that this phenomenon was a manifestation of rickettsial vasculitis.

Anti-Bacterial Agents↗
PubMed2005

Multispacer typing of Rickettsia prowazekii enabling epidemiological studies of epidemic typhus.

Currently, there is no tool for typing Rickettsia prowazekii, the causative agent of epidemic typhus, currently considered a potential bioterrorism agent, at the strain level. To test if the multispacer typing (MST) method could differentiate strains of R. prowazekii, we amplified and sequenced the 25 most variable intergenic spacers between the R. prowazekii and R. conorii genomes in five strains and 10 body louse amplicons of R. prowazekii from various geographic origins. Two intergenic spacers, i.e., rpmE/tRNA(fMet) and serS/virB4, were variable among tested R. prowazekii isolates and allowed identification of three and two genotypes, respectively. When the genotypes obtained from the two spacers were combined, we identified four different genotypes. MST demonstrated that several R. prowazekii strains circulated in human body lice during an outbreak of epidemic typhus in Burundi. This may help to discriminate between natural and intentional outbreaks. Our study supports the usefulness of MST as a versatile method for rickettsial strain genotyping.

Animals↗
PubMed1975

Mammals and scrub typhus ecology in peninsular Malaysia.

The overall comparisons of habitats are given in (Table III). The habitats are arranged in order of extent of alterations by man, with the least disturbed at the top. The highest average blood isolation rates came from the least disturbed areas. The highest monthly maximal rickettsial isolation rates from blood and maximal prevalence rates of antibody per month were also obtained at Bukit Lanjan, the habitat least altered by activities of man. The lowest average blood isolation rate (6%) and the lowest monthly maximal rickettsial isolation and antibody prevalence rates were obtained at Bukit Mandol, the habitat most extensively and intensively altered by man. The intermediate habitats had intermediate rates. We caution anyone interpreting these observations, however, in terms of human disease, which seem to be associated with hyperendemic foci. Here we are not dealing with hyperendemicity from the standpoint of human disease, but present evidence of widespread endemicity from which hyperendemic foci may derive. Also, we have not yet identified the prevalent strains and do not know their infectivity to man.

Animals↗