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PubMed1983

[Q fever in the Ukraine].

Q fever occurs in all geographical landscape zones and in most administrative regions of the Ukrainian SSR. The disease was diagnosed in those areas where no such cases had ever been registered. In the Kharkov region the examination of 425 fever patients with unclear diagnosis resulted in diagnosing 5 cases of Q fever. The proportion of seropositive persons among different professional groups of the population in the eastern part of the republic was determined (6.9% among workers of meat-packing factories, 8.7% among workers of fur- and wool-treating establishments, 5.2% among stock breeders). At the farms of the Kharkov, Poltava and Sumy regions the spread of infection among large cattle was 2.3% and among small cattle 5.6%. Rickettsial carriership revealed in hard ticks collected in the Kharkov region indicated the possibility of the existence of the natural focus of Q fever in this zone and increased the available information on the presence of the territories with the natural foci of this infection in the Ukraine.

Agricultural Workers' Diseases↗
PubMed1986

Production and characterization of monoclonal strain-specific antibodies against prototype strains of Rickettsia tsutsugamushi.

We have developed 18 hybridoma cell lines which secrete murine monoclonal strain-specific antibodies to prototype strains of Rickettsia tsutsugamushi: nine anti-Gilliam, four anti-Karp and five anti-Kato antibodies. All the monoclonal antibodies reacted only with their homologous strains in direct and indirect immunofluorescence (IF), or indirect immunoperoxidase (IP) test. By IF and IP tests with the monoclonal antibodies, 22 strains of R. tsutsugamushi, which were newly isolated from mites, field rodents and patients with Tsutsugamushi disease (scrub typhus) in Japan, were all clearly identified as either Gilliam or Karp type. Analysis by polyacrylamide gel electrophoresis and immunoblotting techniques revealed that the monoclonal antibodies recognized primarily the polypeptides of an apparent molecular weight of 54 to 56 kilodaltons of the homologous rickettsial surface. The monoclonal antibodies produced in the present study should enhance the serotyping and further analytical investigation of the rickettsial antigens since they recognize the strain- or type-specific polypeptides and do not show any cross-reaction among strains.

Animals↗
PubMed1969

Ecology of tick vectors of American spotted fever.

The author reviews the natural history of the tick vectors of American spotted fever. The discussion concerns the ecology of the Rocky Mountain wood tick, Dermacentor andersoni, the American dog tick, Dermacentor variabilis, and the lone-star tick, Amblyomma americanum, all of which are proven vectors of Rocky Mountain spotted fever to man. Also included are the rabbit tick, Haemaphysalis leporispalustris and Dermacentor parumapertus, which very rarely bite man but which are considered of importance in maintaining and distributing Rickettsia rickettsi, the etiological agent of Rocky Mountain spotted fever, in nature. Brief reference is also made to recently developed techniques for studying the ecology of tick vectors.

Animals↗
PubMed1995

Serological evidence of Ehrlichia canis in dogs in southern Italy.

A serological survey of antibodies to Ehrlichia canis was performed on 423 dogs. The indirect fluorescence antibody test was employed. For this purpose mouse-dog hybridoma cells infected with Ehrlichia canis were used. Eighty-five dogs were found positive. The study tested 25 dogs with clinical signs suggestive of a rickettsial infection. Twenty-three of them had antibodies to E. canis.

Animals↗
PubMed1996

Heartwater in sheep and goats: a review.

Heartwater (cowdriosis) is an important, often fatal, tick-borne disease of domestic and wild ruminants in sub-Saharan Africa and some Indian Ocean and Caribbean islands. The causal agent, Cowdria ruminantium (Cowdry 1925), is a rickettsia closely related to members of the genus Ehrlichia, and is probably a part of a complex of genomic species. Imported breeds of sheep and goats (especially Angoras) are highly susceptible, but indigenous populations of endemic areas may be resistant to infection. Very young stock (less than 9 d old) possess a natural resistance that is unrelated to the immune status of the dams. Symptoms of heartwater vary, but usually begin with fever and may involve neurological signs and respiratory distress. Clinical diagnosis is based on symptoms, history of tick-exposure and post-mortem findings, and is confirmed by demonstration of characteristic rickettsial organisms in vascular endothelial cells. Laboratory diagnosis is retrospective and includes fluorescent antibody and enzyme-linked immunosorbent assays. Serological tests are compromised by non-specific reactions with certain Ehrlichia spp. DNA and oligonucleotide probes have been developed, but are thus far unavailable in many countries affected by heartwater. Treatment with tetracyclines is effective if begun in the early stages of infection. Control is based on a knowledge of the disease cycle in nature, and is achieved through judicious tick control, vaccination or both. A virulent, blood-based vaccine is available. Existence of a carrier state in recovered animals, including wild ruminants, complicates control efforts, and eradication is feasible only in circumscribed foci. Problem areas in fundamental and applied research on heartwater, as it affects sheep and goats, are discussed.

Animals↗
PubMed2001

Rickettsial infection in murine models activates an early anti-rickettsial effect mediated by NK cells and associated with production of gamma interferon.

Natural killer (NK) cell activity was significantly increased on days 2-6 of infection in the Rickettsia conorii-infected C3H/HeN mice and on day 2 in the Rickettsia typhi-infected C57BL/6 mice. Depletion of NK cell activity utilizing anti-NK1.1 monoclonal antibody enhanced the susceptibility of normally resistant C57BL/6 mice to infection with R. typhi, and depletion of NK cell activity with antibody to asialo GM1 enhanced the susceptibility of C3H/HeN mice to infection with R. conorii. Serum gamma interferon was increased in R. conorii-infected C3H/HeN mice compared with NK cell-depleted, infected mice during the early course of infection. Additionally, the NK cell activating cytokine IL-12 was elevated in the sera of infected mice during the time period representing enhanced NK cell activity compared with uninfected mice. Thus, it appears that NK cells contribute to the early anti-rickettsial immune response, likely via a mechanism involving gamma interferon.

Animals↗
PubMed1982

Spondweni virus infection in a foreign resident of Upper Volta.

Spondweni virus is a mosquito-borne flavivirus previously reported to cause human disease in Southern and West Africa. A serologically confirmed case of Spondweni virus infection in a U.S. citizen residing in Upper Volta is reported. Symptoms included fever, chills, headache, myalgia, nausea, and rash. A greyish mucoid lining was present on the posterior pharynx. The differential diagnosis included rickettsial infection, leptospirosis, typhoid fever, and numerous viral illnesses including Lassa fever. Evidence of Spondweni virus infection was also found in two other U.S. citizens residing in Gabon and Cameroon. Spondweni virus might be a cause of acute febrile illness throughout West Africa, and its presence should be considered in the differential diagnosis of febrile illness and in antibody surveys in that region.

Adult↗
PubMed1992

Characterization and comparison of Australian human spotted fever group rickettsiae.

The microbiological and molecular characteristics of the rickettsiae isolated from humans with Queensland tick typhus (QTT) caused by Rickettsia australis and the recently described Flinders Island spotted fever (FISF) were compared. Clinically and serologically, the diseases are similar. Cell culture reveals differences in the plaque-forming abilities of the isolates. Characterization of the gene encoding the genus-specific 17-kDa antigen of R. australis revealed a unique nucleotide sequence unlike those of the FISF isolate and Rickettsia rickettsii. Southern blot analysis of rickettsial DNA from the isolates with a 17-kDa-antigen gene probe revealed the presence of this gene in all isolates but no difference in banding patterns. When a probe for the rRNA genes was used, clear differences in banding patterns of isolates from patients with QTT and FISF were revealed. Thus, the rickettsiae isolated from patients with FISF differ from those from patients with QTT and may represent a new rickettsial species.

Antigens, Bacterial↗
PubMed1992

Experimental transmission of Cowdria ruminantium (Rickettsiales) by the American reptile tick Amblyomma dissimile Koch, 1844.

A Senegalese isolate of the rickettsia Cowdria ruminantium was transmitted transstadially by nymphs of the American reptile tick Amblyomma dissimile. Only eight nymphs, fed as larvae on a Saanen goat reacting to heartwater, were required to transmit fatal heartwater to another susceptible goat. Since A. dissimile usually feeds on snakes, iguanas and lizards in central America, the tick is not considered to play a significant role in the transmission of heartwater between ruminants. However, the tick could play a role in maintaining a rickettsial reservoir in reptile populations, since it has been shown that an African reptile can be a subclinical carrier of C. ruminantium, infective to vector ticks.

Animals↗
PubMedDate not supplied

[The disseminated intravascular coagulation syndrome and infection].

The disseminated intravascular coagulation syndrome (1) Definition. History. (2) Etiopathogeny of the disseminated intravascular coagulation syndrome. (3) The clinical and laboratory diagnosis of the disseminated intravascular coagulation syndrome. (4) The principal infections in which the disseminated intravascular coagulation syndrome has been described: bacterial, viral, rickettsial, parasitic, mycotic. (5) Treatment of the disseminated intravascular coagulation syndrome.

Aminocaproates↗
PubMed1986

Kawasaki syndrome: a controlled study of an outbreak in Wisconsin.

The etiology of Kawasaki syndrome remains unestablished, although a possible role has been suggested for exposure to the application of carpet shampoo, house dust mites, and rickettsial infection. During an outbreak of 20 cases of Kawasaki syndrome that occurred in southeastern Wisconsin from November 1982 through March 1983, a case-control study was done of 15 cases and 30 matched controls. The study included questionnaire administration, dust collection from homes, and serum specimen collection. Only one patient had been exposed to a shampooed carpet within 30 days before onset of illness. No differences were noted between cases and controls in the degree of exposure to house dust mite-associated factors in the home, nor in the occurrence, density and species-specific prevalence of house dust mites in the home. Meadow voles exposed to house dust mites from the homes of patients did not develop serologic or pathologic evidence of infection due to rickettsiae in the spotted fever and typhus groups or Coxiella burnetii. Anti-mite-specific immunoglobulin E was not detected in serum specimens from cases or controls. Results from this study do not support hypotheses suggesting that the development of Kawasaki syndrome is associated with exposure to application of carpet shampoo, house dust mites, or rickettsial infection.

Animals↗
PubMed2003

Serologically detected "new" tick-borne zoonoses in eastern Croatia.

AIM: To establish serologically a contact with causative agents of human monocytic and granulocytic ehrlichiosis, human babesiosis, recently detected rickettsioses, and Lyme disease in individuals with a history of tick bite from three counties in eastern Croatia. METHODS: Seroepidemiologic testing was performed in 102 subjects with a history of tick bite, who either requested examination for a tick bite or were suspected of having tick-borne disease. The study was carried out during the 1998-1999 period in the area of the Vukovar-Srijem, Osijek-Baranya, and Brod-Posavina counties. Serum analysis was performed by indirect immunofluorescence assay for the detection of antibodies to causative agents of human monocytic and granulocytic ehrlichiosis (Ehrlichia chaffeensis and human granulocytic ehrlichiosis agent), human babesiosis (Babesia divergens), and rickettsiosis. Enzyme-linked immunosorbent assay was used for the detection of antibodies to the spirochete Borrelia burgdorferi, the cause of Lyme disease. The assays were performed at the Department of Microbiology, Osijek Public Health Institute in Osijek, and their results were confirmed at the Department of Microbiology and Immunology, School of Medicine in Ljubljana, Slovenia. RESULTS: Ehrlichia chaffensis antibodies were detected in 5 sera, and antibodies to the causative agent of human granulocytic ehrlichiosis in 7 sera. A low titer of antibodies to the etiologic agent of babesiosis (Babesia microti) was detected only in a single serum. Eight sera that were positive for rickettsial antibodies contained rather high titers of antibodies against Rickettsia conorii, the agent of Mediterranean fever, and Rickettsia rickettsii, the agent of Rocky Mountain spotted fever. In six out of these 8 sera, antibodies to Rickettsia typhi, the cause of murine typhus, were detected possibly as a cross-reaction with some "newly detected" rickettsia circulating in this part of Europe, most likely Rickettsia slovaca. Positive titer of antibodies to Borrelia burgdorferi was detected in 15 sera. CONCLUSION: The agents of human monocytic and granulocytic ehrlichiosis and of possibly newly detected rickettsiae were indirectly demonstrated to circulate in eastern parts of Croatia. The results obtained by IFA failed to provide definite evidence for the circulation of the human babesiosis agent, because the IFA used in our study detected Babesia microti, which prevails in the USA, but not Babesia divergens, which is the predominant cause of the disease in Europe. Serologic evidence for Borrelia burgdorferi infection was demonstrated in 80% of the subjects suspected of having the skin manifestation of Lyme disease.

Adolescent↗
PubMed1997

Rickettsia rickettsii growth and temperature-inducible protein expression in embryonic tick cell lines.

Rickettsia rickettsii has limited adverse effects on its arthropod vector, but causes severe disease in man. To model differences in host-parasite interaction, R. rickettsii growth and protein expression were examined at temperatures reflective of host environment in the tick cell lines DALBE3 and IDE2, the human endothelial cell line ECV304, and the African green monkey kidney cell line Vero76. At low multiplicities of infection, rickettsial titres increased 10(2)-10(3)-fold in all cell lines after incubation for 3 days at 34 degrees C. At higher multiplicities and with extended incubation, R. rickettsii showed enhanced survival in tick versus mammalian cells. No difference in rickettsial ultrastructure or protein profiles was detected between different host cell types. Rickettsial proteins of 42, 43, 48, 75 and 100 kDa are induced in tick cells shifted from 28 degrees to 34 degrees C, but not in cells maintained at 28 degrees C. This temperature response may be associated with expression of rickettsial determinants that are pathogenic to mammalian hosts.

Animals↗
PubMed1995

Evaluation of the pathogenic potential of Rickettsia canada and Rickettsia prowazekii organisms in dogs.

An unusual pattern of seroreactivity to antigens of rickettsial organisms (Rickettsia rickettsii, R rhipicephali, R montana, and R bellii), particularly to R bellii antigen, was detected in 3 dogs during a 2-month period. Thus, studies were initiated to clarify the pathogenic potential of the more distantly related rickettsial organisms (R canada and R prowazekii) in dogs. Because R bellii are nonpathogenic rickettsiae that share numerous common properties with spotted fever-group and typhus-group rickettsiae, and because closely related pathogenic relatives of R bellii have not been identified, we examined the pathogenic potential of these typhus-group rickettsiae by testing stored serum samples, by attempting rickettsial isolation from febrile dogs, and by experimentally inoculating dogs with R canada and R prowazekii. Evaluation of results of a serosurvey of acute and convalescent serum samples from 80 dogs in which Rocky Mountain spotted fever had been considered as a differential diagnosis, but seroconversion to R rickettsii had not been documented, identified 1 dog with a fourfold increase in antibody titer to R rhipicephali and 3 dogs with fourfold increases in antibody titer to 1 or more antigens of typhus-group rickettsial organisms. A study of 15 dogs that were febrile during summer months failed to identify serologic or tissue culture evidence of typhus-group rickettsial infection or typhus-group rickettsemia, but did result in isolation of R rickettsii and Ehrlichia canis, respectively, from 1 dog each. In our final study, after experimentally inoculating 6 dogs with R canada and R prowazekii, all dogs seroconverted to the respective rickettsiae, but rickettsemia or clinical and hematologic evidence of disease was not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1978

Alterations of body fluid compartments and distribution of tissue water and electrolytes in rhesus monkeys with rocky mountain spotted fever.

Chair-restrained rhesus monkeys (Macaca mulatta) were inoculated subcutaneously with 10(2)--10(3) plaque-forming units of virulent Rickettsia rickettsii. The latent period for fever and rickettsemia was three to four days; death occurred six to eight days after infection. Total circulatory electrolyte levels and fluid volumes, including plasma, red blood cell, true circulatory blood, and extracellular fluid, increased. The expansion of the extracellular and plasma volumes resembled findings reported during severe Rocky Mountain spotted fever in humans, guinea pigs, and rabbits. Total water content of the liver also increased. Intracellular concentrations of K+, as well as total Na+ and K+, decreased in the diaphragm. Both the lung and medulla oblongata showed increased levels of intracellular Na+ and water with simultaneously decreased levels of extracellular Na+ and water. Such an intracellular overhydration of the medulla oblongata could contribute to death as a result of depression of the cardiovascular and respiratory centers. On the basis of the findings in monkeys, the intravenous infusion of fluids and electrolytes during clinical therapy of severe rickettsial infections should be considered extremely dangerous.

Animals↗
PubMed1985

Rocky Mountain spotted fever mimicking acute cholecystitis.

Rocky Mountain spotted fever can present with predominantly abdominal symptoms including nausea, vomiting, diarrhea, and abdominal pain. Two elderly patients presented with an acute febrile illness and abdominal symptoms. Rash was not present initially. Workup disclosed cholelithiasis in one, and a thickened gallbladder wall surrounded by a sonolucent zone suggesting a pericholecystic abscess was found by ultrasonography in the other. Both patients underwent emergency laparotomy, with cholecystectomy in both and appendectomy in one. Both patients died several days postoperatively. Pathologic specimens reviewed later showed that multiple blood vessels of the gallbladder and the appendix were infected with Rickettsia rickettsii, and there was focal vascular thrombosis and hemorrhage. These documented direct rickettsial infections and lesions in the blood vessels of abdominal viscera suggest the basis for the abdominal symptoms in Rocky Mountain spotted fever.

Acute Disease↗