Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RICKETTSIAL DISEASES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMed2006

Detection and identification of a novel spotted fever group rickettsia in Western Australia.

The extent to which rickettsiae are present in Western Australia (WA) is largely unknown. Recently there has been anecdotal evidence of a disease of unknown but possibly rickettsial origin occurring on Barrow Island, WA. Ticks were collected from people and screened using PCR. The rickettsial species was then cultured and its novelty and phylogenetic position examined. The infecting rickettsial species is divergent enough to be classified as a novel species. Sequence data suggest that the evolutionary route for Australian rickettsiae did not progress through a recent common ancestor. The pathogenic potential of the novel species is as yet unknown.

Evolution, Molecular↗
PubMed1981

Serological study with rickettsial antigens in erythema chronicum migrans.

21 sera of 13 patients with erythema chronicum migrans (ECM) and related diseases were examined for the presence of antibodies against 14 rickettsial antigens by using 3 serological techniques in 2 laboratories. Most tests were negative. This indicates that ECM and related diseases are not due to an hitherto known rickettsia. 5 out of 158 tests showed, however, positive reactions in low titers against Rickettsia akari and Coxiella burnetii. Thus, an antigenic relationship may exist between one or more rickettsia(e) and the etiologic agent of ECM.

Antibodies, Bacterial↗
PubMed2005

Balb/c mouse model and real-time quantitative polymerase chain reaction for evaluation of the immunoprotectivity against Q fever.

The Balb/c mice were infected with Coxiella burnetii and samples of blood and major organs from the infected mice were collected on days 1 to 14 after infection. The DNAs extracted from the samples were detected by a developed real-time quantitative PCR specific for C. burnetii and high loads of C. burnetii were found in spleens, livers, and lungs, particularly in spleens. The Balb/c mice were immunized with whole cell antigen (WCA) of C. burnetii and coxiella loads in spleens of mice were assessed by the real-time quantitative PCR on day 7 after challenge with C. burnetii. The analysis suggested that phase I whole cells were excellent immunogen that elicited complete protection against coxiella infection by two-booster but not one-booster immunization. The results suggest that the combination of Balb/c model and the real-time quantitative PCR assay is a reliable and sensitive way to evaluate the efficiency of vaccines against Q fever.

Animals↗
PubMedDate not supplied

Survey of rickettsial antibodies at two local sites and review of rickettsiosis in Papua New Guinea.

The status of rickettsial infection in Papua New Guinea (PNG) is unknown although several reports of typhus-like illnesses infecting predominantly white settlers and the Allied troops during World War 2 were published between 1930 and 1945. We performed a serological survey for evidence of rickettsial infection by measuring rickettsia-specific antibody levels in the blood of 191 non-randomly selected Papua New Guineans living in Port Moresby (n=93) and in the highland villages of Samberigi (n=98). Antibodies were measured by a microimmunofluorescence method using a panel of rickettsial antigens of a number of species and strains. In addition, we have reviewed the current status of rickettsiosis in PNG. Overall, we were able to demonstrate significant titres of antibodies to two groups of rickettsiae, the scrub typhus group (STG) and the spotted fever group (SFG). All positive individuals (7/191) were residents of Port Moresby. None from the highlands showed any significant levels of antibodies to rickettsiae. The strains detected within each group were Gilliam and Karp for STG and, for SFG, Rickettsia honei, R. conorii, R. sibirica, R. rickettsii, R. australis and R. akari. No significant antibody titres to typhus group infection were detected in either Port Moresby or highland volunteers. These findings were not surprising given previous reports of typhus-like illnesses and favourable environmental characteristics for rickettsiae in some parts of PNG. Until a definite status of this disease is known, we suggest that rickettsial infection be included as a differential diagnosis for patients presenting with acute febrile illness in Port Moresby and surrounding areas.

Humans↗
PubMed2004

Characterization of the pCS20 region of different Ehrlichia ruminantium isolates.

Heartwater is a serious tick-borne disease of ruminants caused by the rickettsial organism Ehrlichia (Cowdria) ruminantium. A diagnostic test, targeting the pCS20 genomic region and using PCR amplification and probe hybridization, detects E. ruminantium infection in ticks and animals. However, only the pCS20 sequence of the Crystal Springs E. ruminantium isolate is available and the existence of sequence variation amongst different E. ruminantium isolates has not been determined. Primers were designed from the published pCS20 sequence to obtain sequences of the pCS20 region of various E. ruminantium isolates. These primers were unable to amplify the pCS20 region from genomic Welgevonden DNA and genome walking was used to characterize the pCS20 region. This technique showed that the published pCS20 sequence is from a chimeric clone. Sequences of the pCS20 region of 14 different E. ruminantium isolates were determined after amplification with newly designed primers. Sequencing data indicated that West African E. ruminantium isolates are highly conserved, whereas more variation occurs amongst the southern African isolates. These results facilitated the design of a short pCS20 probe and a large PCR target that improved the sensitivity of the E. ruminantium detection assay.

Animals↗
PubMed2000

Sequence and expression analysis of a surface antigen gene family of the rickettsia Anaplasma marginale.

The tick-borne rickettsial organism, Anaplasma marginale, causes a disease in cattle of world-wide economic significance. This disease, anaplasmosis, is characterized by severe hemolytic anemia, high levels of rickettsemia and, often, death in animals over 3years of age. Animals that survive acute infection remain carriers, with continuous sub-microscopic cycles of rickettsemia that can persist for the lifetime of the animal. In the search for potential recombinant immunogens, it was discovered that several surface proteins of A. marginale encode polymorphic multigene families. Despite the small size of the genome (approx. 1250kb), these surface antigen gene families comprise greater than 2% of the genome. We present here a mapping, sequencing and expression analysis of five complete or partial genes encoding MSP1b in a Florida strain of A. marginale. Two genes are complete; they encode mRNA that is translated into polypeptide products. Three genes are incomplete and appear to be derived from the complete genes by a series of segmental intragenic recombinations. In two of the incomplete genes, 5' sequence in the incomplete genes is 3' sequence in the complete genes. Recombination within these gene families may generate diversity in surface antigens through combinatorial rearrangements. This could contribute to persistence in the chronic infections caused by A. marginale and related rickettsiae.

Anaplasma↗
PubMed2002

Ehrlichia ruminantium infection (heartwater) in wild animals.

Several wild animal species have been implicated as hosts of Ehrlichia ruminantium (formerly Cowdria ruminantium), the rickettsial agent causing heartwater, a fatal disease of domestic ruminants in sub-Saharan Africa and eastern Caribbean. However, evidence for infection in most wild species is inconclusive because of inadequate diagnostic techniques. Infection has been proven only in 12 African ruminants, three non-African ruminants and two African rodents. A subclinical carrier state occurs in eight of the African ruminant species. Further studies on E. ruminantium infection in wild animal species are needed in order to determine the host range of this pathogen accurately. The host range of Ehrlichia ruminantium in wildlife is reviewed here and the role played by these species in the epidemiology and spread of heartwater is discussed.

Africa↗