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PubMed1992

DNA probes for detecting Coxiella burnetii strains.

Methods have been developed for the rapid detection of C. burnetii by specific hybridization of labelled DNA probes to rickettsial plasmid DNA sequences present in clinical samples. One DNA probe detects all C. burnetii strains, while additional probes differentiate, between organisms associated with chronic or acute disease. Using these probes, C. burnetii can be identified in blood, urine, and tissue samples. The plasmid-derived DNA probes detect as few as 10(4) organisms and less than 1 ng of Coxiella DNA. Host-cell DNA has no effect on the hybridization signal from C. burnetii DNA, and these probes do not cross-react with a variety of microorganisms, including both common laboratory contaminants and organisms that cause clinical symptoms similar to those of Q fever. The sensitivity of the assay is markedly enhanced when the procedure employs the polymerase chain reaction (PCR) to amplify C. burnetii DNA. This requires construction of oligonucleotide primers to DNA sequences flanking the target region of the DNA being amplified. For C. burnetii detection, several sets of primers have been prepared. One set is derived from the QpH1 H fragment, a region that is shared by all C. burnetii plasmids (homologous sequences are also present in the plasmidless strains of C. burnetii). The H primers detect all strains of C. burnetii. To differentiate between C. burnetii strains, additional primers, specific for DNA sequences that are unique either to chronic or acute disease-related strains of C. burnetii are employed. PCR amplifies target sequences up to 10(6)-fold. When DNA hybridization is used in conjunction with PCR, the test can detect less than 10 C. burnetii cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1982

Antibodies to spotted fever-group rickettsiae in dogs and prevalence of infected ticks in southern Connecticut.

Blood samples and ticks were obtained from dogs to assess canine exposure to spotted fever-group (SFG) rickettsiae during 1978-1980 in southern Connecticut. Of the 1,576 dog sera screened by microimmunofluorescence. 174 (11.0%) contained specific antibodies at titers greater than or equal to 1:64 against Rickettsia montana (n = 34), R rickettsii (n = 31), R rhipicephali (n = 19), or the unclassified 369-C rickettsia (n = 90). End points greater than or equal to 1:8,192 to R rickettsii and to R rhipicephali were recorded for 6 and 3 sera, respectively. Seropositivity rates from southwestern and southeastern Connecticut were similar (about 11%), with positive sera obtained from each region in nearly all months of the investigation. Rates were between 10% for dogs 2 to 7 years old and 14% for those greater than or equal to 8 years. Eight of 629 Dermacentor variabilis, 1 of 18 Ixodes dammini, and 2 of 3 Amblyomma americanum were positive by direct immunofluorescence for SFG rickettsiae. Thirteen D variabilis contained unidentified, long, bacillus-like organisms that differed from the short, ovoid (coccal) forms typical fo the spotted-fever agent, R rickettsii. With the exposure to infected ticks and production of type-specific antibodies against at least 4 SFG antigens, dogs may serve as suitable enzootic or epizootic indicators of rickettsial activity.

Animals↗
PubMedDate not supplied

Tick- and flea-borne rickettsial emerging zoonoses.

Between 1984 and 2004, nine more species or subspecies of spotted fever rickettsiae were identified as emerging agents of tick-borne rickettsioses throughout the world. Six of these species had first been isolated from ticks and later found to be pathogenic to humans. The most recent example is Rickettsia parkeri, recognized as a human pathogen more than 60 years after its initial isolation from ticks. A new spotted fever rickettsia, R. felis was also found to be associated with fleas and to be a human pathogen. Similarly, bacteria within the family Anaplasmataceae have been considered to be of veterinary importance only, yet three species have been implicated in human diseases in recent years, including Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis, Anaplasma phagocytophilum, the agent of human anaplasmosis (formerly known as "human granulocytic ehrlichiosis agent", E. equi and E. phagocytophila), and finally Ehrlichia ewingii, which causes granulocytic ehrlichiosis in humans. We present here an overview of the various tick- and flea-borne rickettsial zoonoses described in the last 20 years, focusing on the ecological, epidemiological and clinical aspects.

Anaplasmosis↗
PubMed1998

[Cutaneous signs of Rickettsia and related microorganisms].

INTRODUCTION: Rickettsiosis are emerging, life-threatening infectious diseases that are world-wide distributed and have various manifestations. Most of the time, skin involvement is the prominent feature of clinical manifestations. Clinicians must therefore be well aware of these various clinical pictures. CURRENT KNOWLEDGE AND KEY POINTS: Knowledge about rickettsial infections has recently improved due to either the identification of new vectors and reservoirs, the description of new systemic and cutaneous signs and symptoms, or the amelioration of diagnosis methods. Cutaneous manifestations mainly depend on the type of microorganism and on the host characteristics. In some cases, they are so typical that their only identification would lead to the diagnosis. FUTURE PROSPECTS AND PROJECTS: As growing population movements may lead to an increase in the disease incidence, detailed knowledge of clinical, particularly cutaneous, manifestations of rickettsiosis is required in order to improve both diagnosis and treatment. When identified, cutaneous manifestations of rickettsiosis allow the clinician to confirm rapidly the diagnosis, using polymerase chain reaction or immunofluorescence and to institute prompt and specific treatment, thus reducing unfavorable disease outcome.

Diagnosis, Differential↗
PubMed2004

Dermatologic Infectious Diseases in International Travelers.

Skin lesions provide an important clue to the diagnoses of many infections in returned travelers. New information related to epidemiology, recognition, diagnosis, or management is described for the systemic infections--dengue fever, several of the rickettsial infections, African trypanosomiasis, and coccidioidomycosis. Many pathogens cause focal skin findings. Recent findings are presented for cutaneous leishmaniasis, Buruli ulcer, gnatho-stomiasis, cutaneous larva migrans, myiasis, tungiasis, and scabies. This paper describes the most common skin problems in returning travelers and outlines the types of infections that cause skin lesions, as defined by morphologic characteristics.

Journal Article↗
PubMedDate not supplied

Visceral leishmaniasis in a New York foxhound kennel.

Although endemic throughout much of the world, autochthonous visceral leishmaniasis has been reported on only 3 previous occasions in North America. After diagnosis of visceral leishmaniasis in 4 foxhounds from a kennel in Dutchess County, New York (index kennel), serum and ethylenediamine-tetraacetic acid (EDTA)-anticoagulated blood were collected from the remaining 108 American or cross-bred foxhounds in the index kennel and from 30 Beagles and Basset Hounds that were periodically housed in the index kennel. Samples were analyzed for antibodies to or DNA of tickborne disease pathogens and Leishmania spp. Most dogs had antibodies to Rickettsia spp., Ehrlichia spp., Babesia spp., or some combination of these pathogens but not to Bartonella vinsonii (berkhoffi). However, DNA of rickettsial, ehrlichial, or babesial agents was detected in only 9 dogs. Visceral leishmaniasis was diagnosed in 46 of 112 (41%) foxhounds from the index kennel but was not diagnosed in any of the Beagles and Basset Hounds. A positive Leishmania status was defined by 1 or more of the following criteria: a Leishmania antibody titer > or = 1:64, positive Leishmania polymerase chain reaction (PCR), positive Leishmania culture, or identification of Leishmania amastigotes by cytology or histopathology. The species and zymodeme of Leishmania that infected the foxhounds was determined to be Leishmania infantum MON-1 by isoenzyme electrophoresis. Foxhounds that were > 18 months of age or that had traveled to the southeastern United States were more likely to be diagnosed with visceral leishmaniasis. Transmission of Leishmania spp. in kennel outbreaks may involve exposure to an insect vector, direct transmission, or vertical transmission.

Animals↗
PubMedDate not supplied

The new program of the World Health Organization in medical virology.

The World Health Organization (WHO) convened a Scientific Group to adapt its program in virus diseases to recent progress in virology. The program consists of (a) general activities, such as reference services and the supplying of reagents by the WHO Collaborating Centres and (b) specific activities to solve problems-including the promotion of necessary research-caused by certain diseases of public health importance. The Group reviewed problems caused by influenza and other respiratory viruses, enteroviruses, gastroenteritis viruses (for which types A and B have been proposed as a convenient nomenclature), viral hepatitis, viruses in water and sewage, arboviruses, arenaviruses and Marburg virus, measles and rubella vaccination, smallpox, rabies, chronic infections, herpesviruses, oncogenic viruses, congenital infections, nosocomial infections, chlamydial and rickettsial infections, and mycoplasma infections.

Arboviruses↗
PubMed1998

Acute Q fever pneumonia: a review of 80 hospitalized patients.

STUDY OBJECTIVES: To emphasize epidemiologic, clinical, or radiologic characteristics whose detection could lead to an early diagnosis and to enhance therapeutic efficacy. PATIENTS: Eighty hospitalized patients from 1982 to 1996. DESIGN: The diagnosis of Q fever infection was serologically confirmed in all the patients (phase II Coxiella burnetii antibody) using the complement fixation test and/or the indirect immunofluorescence antibody test. RESULTS: Patients from rural and urban areas were noted in the same proportion; however, the usual epidemiologic factors such as contact with cats or farm animals were found in 40% of the patients. Mean age+/-SD was 49+/-20 years, and there was a higher sex ratio of male to female patients (1:3.44). We found a specific seasonal distribution since 80% of the cases occurred between February and May. Delay before referring to hospital was 8.2+/-7.8 days, while 69.3% of the patients received an antibiotic treatment that was mainly penicillin or cephalosporin. The dominant clinical features were dry cough and high fever, as the maximal temperature reached more then 40 degrees C in 58% of the patients. Digestive symptoms were rare. WBC count remained within normal range in 80% of the cases with a low proportion of lymphocytes in half of the patients, and the sedimentation rate was usually elevated (55+/-34 mm). Altered liver function consisted more frequently in an elevated level of alkaline phosphatase (70% of the cases) than transaminases, while hyponatremia was frequently mentioned (28.2% of the patients). We found radiologic evidence of unique lobar or segmental alveolar opacity involving more likely the lower lobes in 55 patients, and multiple or interstitial opacities in the others. Chest radiographs were considered normal in eight patients. The clinical response was favorable in all the patients with a reduction in fever 4.8+/-3.9 days after the start of treatment with the second antibiotic that included mainly erythromycin or quinolones, and chest radiographs returned to normal in 81% of the patients within the first month.

Acute Disease↗
PubMed1990

[Disseminated intravascular coagulation in eperythrozoonosis of swine].

Investigations were carried out on the influence of latent and clinically manifest Eperythrozoon suis infection upon haemostasis in swine. The study was carried out with 14 German Landrace pigs. Latent eperythrozoonosis was induced in 7 animals by experimental infection. Splenectomy of these 7 animals and 2 spontaneously infected pigs led to clinical manifestation of eperythrozoonosis. Five clinically healthy pigs were splenectomized and served as controls. In healthy pigs splenectomy was followed by a transient rise in fibrinogen and platelet count. Latent infection with Eperythrozoon suis did not cause an impairment of haemostasis. Acute eperythrozoonosis was associated with increased haemorrhagic tendency considered to be a consequence of intravascular coagulation and subsequent consumption coagulopathy. There was a prolongation of partial thromboplastin time and prothrombin time (Quick) and a decrease of platelet count. Thrombelastography showed prolongation of reaction and clot building time and a short-term decrease of maximum amplitude. Deviation from normal values was proportional to the number of red blood cells infected with Eperythrozoon suis. Anti-rickettsial therapy led to quick normalization of haemostasis. Various aspects of the cause and the consequences of the haemostatic defect are discussed with special regard to the underlying disease.

Anaplasmataceae Infections↗
PubMed1996

[A Q-fever pneumonia epidemic in Dusseldorf].

There was an unusually high incidence of atypical pneumonias in the catchment area of the Rhine river near the university of Düsseldorf in July 1994 during a long period of hot and dry weather. The 18 patients described in this paper (5 women and 13 men) complained of sudden onset of fever up to over 40 degrees C, often associated with severe headache and dry cough. Almost all of these patients had previously been healthy and active and of young to middle age (average 38 years) without any bronchopulmonary anamnesis. Radiology revealed that all the patients had in most cases defined pulmonary infiltrates without any specific preference for a particular site. Serology was initially negative, but four weeks later the complement fixation reaction titre was positive for Coxiella burnetii antibodies in 14 patients (78%). All patients became symptom-free within a few days'time when treated with a combination of antibiotics which included doxycycline, whereas the infiltrates receded completely only after several weeks. The occurrence of pulmonary Q-fever in a large northern German conurbation had been rare at that time. Such epidemics, however, were also noted in Berlin (1992) and in Dortmund (1993). The epidemic reported in this article probably originated from one of the frequent flocks of sheep grazing along the banks of the Rhine river near Düsseldorf. The infections were probably acquired by inhalation of airborne organisms in infected aerosols derived from infected sheep, promoted by the long-term very hot and dry weather which was at the same time very windy, leading to an unusually extensive spreading of the pathogens throughout a very large infected aerosol area.

Adult↗
PubMed1985

Immunosuppression associated with the development of chronic infections with Rickettsia tsutsugamushi: adherent suppressor cell activity and macrophage activation.

Measures of general immunocompetency such as lymphocyte responses to mitogens and alloantigens and the ability to produce antibody to T-dependent and T-independent antigens were evaluated during the development of chronic infections with Rickettsia tsutsugamushi resulting from subcutaneous infection of BALB/c mice. It was found that a transient immunosuppression was demonstrable regardless of the infecting strain of rickettsiae; however, the immunosuppression produced by the Karp and Kato strains was more pronounced and longer lived. As a marked splenomegaly resulting from inflammatory macrophage influx accompanied this immunosuppression, mitogen- and antigen-induced lymphocyte proliferation was also evaluated after adherent cell depletion or in the presence of indomethacin, and both treatments significantly improved the responses. Isolated splenic macrophages were shown to suppress the responses of lymphocytes from naive mice as well as to exhibit parameters of activation including tumor cell cytolysis and cytostasis and the ability to inhibit the replication of R. tsutsugamushi in vitro. These data suggest an association between macrophage activation involved in rickettsial clearance and a transient immunosuppression.

Animals↗