Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SCRUB TYPHUS”

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 415 records · Page 23Linked to original sources
PubMed1999

Rickettsia serosurvey in Kimberley, Western Australia.

To determine if antibodies to rickettsiae (scrub typhus, spotted fever, and typhus group rickettsiae) occur among persons living in the Kimberley (northern tropical) region of Western Australia, 920 sera collected in a non-random manner in 1996 from patients in Kununurra, Broome, Fitzroy Crossing, Wyndham, Derby, and Halls Creek were tested by micro-immunofluorescence for antibodies to a panel of rickettsial antigens. Of 920 sera examined, 52 (5.6%) were positive for antibodies to one or more of the three groups of rickettsial microorganisms. The largest group of sera (24; 2.6%) were positive for scrub typhus (Orientia tsutsugamushi). Eleven other sera (1.2%) were positive for scrub typhus and spotted fever group rickettsiae and four (0.4%) were positive for scrub typhus, spotted fever group, and typhus group rickettsiae. In addition 13 sera (1.4%) were positive only for spotted fever group rickettsiae. In this study, only titers > or = 1:256 were considered significant. Thus, there is serologic evidence for scrub typhus and spotted fever group rickettsial infections in the Kimberley region of Western Australia. Because of the method of serum collection, it is not possible to determine the prevalence of seropositivity, but the data support the need for a proper epidemiologic study of rickettsial diseases in this region of Australia.

Antibodies, Bacterial↗
PubMed2001

Serological evidence for the continued presence of human rickettsioses in southern India.

Rickettsiosis is generally believed to have disappeared from many parts of India. However, the serological testing of 37 residents of southern India who presented with fever of unknown aetiology in 1996-1998 confirmed that spotted fever, epidemic/endemic typhus and scrub typhus continue to occur in southern India. The epidemiology and magnitude of the problem need to be evaluated.

Adolescent↗
PubMed1994

First cases of spotted fever group rickettsiosis in Thailand.

The first three cases of spotted fever group rickettsiosis from Thailand are reported. The patients presented with fever, headache, lymphadenopathy, and petechial maculopapular rash. One patient also had an eschar and overt evidence of confusion. An indirect fluorescent antibody test, an indirect immunoperoxidase test, and an enzyme-linked immunosorbent assay demonstrated a broad, strong reactions of the sera of the patients with spotted fever group rickettsia antigens of many species, but not with antigens of typhus or scrub typhus rickettsiae. All three patients responded to treatment with a single dose of doxycycline.

Adult↗
PubMed2000

Rickettsial infection in five remote Orang Ulu villages in upper Rejang River, Sarawak, Malaysia.

People in 5 Orang Ulu villages in Sarawak, Malaysia were tested for rickettsial infection by Weil-Felix reaction and by indirect immunoperoxidase reaction. Of those surveyed 9.6% were positive for typhus. Of the positives, 3.8% were positive for tick typhus (7/11), scrub typhus (4/11) or endemic typhus (1/11). The incidence of typhus was higher among semi-nomadic Penans compared with the settled Kayans.

Adolescent↗
PubMed1993

[Treatment of eruptive rickettsioses. Review of the literature from the microbiology to the clinic].

The authors review the literature concerning the treatment of rickettsiosis including Rocky Mountain spotted fever, Mediterranean spotted fever, murine typhus, and Scrub typhus. They report in vitro antibiotic susceptibilities of the causing organisms and in vivo activity on animal models. They also report their clinical experience and these of the literature in the treatment of rickettsiosis.

Animals↗
PubMed1988

Imported rickettsial disease: clinical and epidemiologic features.

PURPOSE AND METHODS: The rickettsioses continue to constitute major health problems in many parts of the world. With increasing international travel, recognition of rickettsial diseases by physicians is becoming more important. The clinical features of four cases of rickettsial disease imported into Canada over a five-year period are presented; two patients with tick typhus (Rickettsia conorii), one patient with scrub typhus (R. tsutsugamushi), and one patient with murine typhus (R. typhi). We also present the North American data over the past 10 years from the Centers for Disease Control (CDC) (Atlanta). RESULTS: Since 1983 in the United States, three cases of imported scrub typhus, all after travel to India, were confirmed, as well as six cases of murine typhus after travel to southeast Asia. At the CDC, 67 imported cases of tick typhus have been confirmed by indirect fluorescent antibody test since 1976; most illnesses occurred after travel to Africa. CONCLUSION: Rickettsial diseases are underrecognized by physicians, who should consider these diagnoses in travelers returning from endemic areas. Since effective treatment is available, prompt diagnosis and treatment are important. In all cases, specific serologic confirmation should be obtained.

Adult↗
PubMed2001

Orientia tsutsugamushi suppresses the production of inflammatory cytokines induced by its own heat-stable component in murine macrophages.

Orientia tsutsugamushi is a Gram-negative obligate intracellular bacterium, which causes scrub typhus. To understand the pathogenesis of scrub typhus, we have investigated the induction of tumor necrosis alpha (TNF-alpha) and interleukin-6 (IL-6) by O. tsutsugamushi in two murine macrophage cell lines. Both live and heat-killed orientia stimulated the production of cytokines in J774A.1 cells. Polymyxin B does not affect the secretion of cytokines. These together with the fact that the immature macrophage cell line, P388D1, did not produce TNF-alpha when induced by either live or heat-killed O. tsutsugamushi strongly argue against any roles of lipopolysaccharide (LPS) in cytokine production. Furthermore, the result that the cytokine responses were more brisk when macrophage cell lines had been induced by heat-killed O. tsutsugamushi than by live organisms strongly suggest that a heat-stable molecule might be responsible for the induction of cytokine production and O. tsutsugamushi might have mechanisms suppressing the production of inflammatory cytokines induced by its own heat-stable molecule.

Animals↗
PubMed1997

[Primary surveillance of spotted fever group antibodies on rats in the Kinmen area].

The positive rate of rickettsial antibodies of 107 rats in the Kinmen area by indirect immunofluorescent antibody (IFA) technique was 0% (0/107) in typhus fever, 38.3% (41/107) in scrub typhus and 66.4% (71/107) in spotted fever group; the positive rate (42.9%) of spotted fever group of 21 rats in Taiwan island also higher than scrub typhus (19.0). It suggests that spotted fever group patients may be present in our country but have not been discovered.

Animals↗
PubMed1992

Diagnosis of typhus infection with Rickettsia tsutsugamushi by polymerase chain reaction.

Two sets of oligonucleotide primers were used to amplify the genomic DNA of Rickettsia tsutsugamushi, the causative agent of scrub typhus (tsutsugamushi disease), by the polymerase chain reaction. Each set of primers amplified 538-bp and 109-bp products, representing part of a gene encoding a possible major 58-kDa immunogenic protein, from whole genomic DNA extracted from R. tsutsugamushi strains Karp, Kato, Gilliam, Kuroki and Kawasaki. No amplification was observed from R. sibirica, R. rickettsii, mouse and human genomic DNA. DNA amplification was observed from crude lysates of peripheral whole blood, tissue homogenates and paraffin-embedded skin biopsy sections obtained from patients with scrub typhus disease. Southern blot analysis demonstrated the specificity of the amplified DNA fragments following hybridisation with a DNA probe generated from R. tsutsugamushi strain Karp. By means of this procedure, a rapid and sensitive diagnosis of scrub typhus disease can be made during the acute stage of this infection.

Acute Disease↗
PubMed2003

Occurrence of Orientia tsutsugamushi in small mammals from Thailand.

Extensive sampling of small mammals was conducted in eight provinces of Thailand between September 9, 1992 and April 29, 2001. A total of 3,498 specimens representing 22 species were collected. Eighty-eight percent (3,089 of 3,498) of the animals were collected from a region in Chiangrai Province, which is commonly recognized as endemic for human scrub typhus. Blood and tissue samples from each animal were tested for the presence of Orientia tsutsugamushi, the etiologic agent of scrub typhus. The predominant species collected were Rattus rattus (53%, n = 1,863), R. losea (18%, n = 638), Bandicota indica (16%, n = 564), and R. exulans (4%, n = 146). Orientia tsutsugamushi was detected in 10 of the 22 species of mammals that included R. bukit (25% infected, 1 of 4), R. rattus (23%, 419 of 1,855), R. argentiventer (22%, 5 of 23), R. berdmorei (22%, 2 of 9), R. losea (13%, 82 of 638), B. indica (9%, 52 of 564), R. koratensis (8%, 1 of 12), B. savilei (3%, 1 of 30), R. exulans (1%, 2 of 146), and Tupaia glis (2%, 1 of 49). Infected animals were found in Chiangrai (18% infected, 563 of 3,084), Bangkok (11%, 1 of 9), Sukothai (3%, 1 of 30), and Nonthaburi (1%, 1 of 69) Provinces. The implications towards scrub typhus maintenance and transmission are discussed.

Animals↗
PubMed2004

Chemokine and cytokine production during Orientia tsutsugamushi infection in mice.

Orientia tsutsugamushi, an obligate intracellular bacterium, is the causative agent of scrub typhus which is histopathologically characterized by inflammatory manifestations, indicating that rickettsiae induce mechanisms that amplify the inflammatory response. To understand the pathogenesis of scrub typhus, we examined chemokine and cytokine production after infection with O. tsutsugamushi in mice. The mRNAs that were upregulated included lymphotactin, RANTES (regulated upon activation, normal T-cell expressed and secreted), macrophage inflammatory proteins 1alpha/beta (MIP-1alpha/beta), MIP-2, monocyte chemoattractant protein 1, lymphotoxin beta, tumor necrosis factor alpha, interleukin-6, gamma-interferon, transforming growth factor beta1, and migration inhibition factor. Peak expression of these chemokines and cytokines was observed between 4 and 8 days after infection. Gene induction was followed by the secretion of chemokine and cytokine proteins. Chemokine profile in infected mice was well correlated with kinetics of inflammatory cell infiltration. Thus, O. tsutsugamushi appears to be a strong inducer of chemokines and cytokines which may, by the attraction and activation of phagocytic leukocytes, significantly contribute to inflammation observed in scrub typhus.

Animals↗
PubMed2003

Prevalence of relative bradycardia in Orientia tsutsugamushi infection.

We investigated 100 febrile patients infected with Orientia tsutsugamushi (the etiologic agent of scrub typhus) for the presence of relative bradycardia, defined as in increase in heart rate of < 10 beats/minutes/1 degree C increase in temperature. The median heart rate response for the entire febrile scrub typhus population was 9.3 beats/minute/degrees C and the prevalence of relative bradycardia was 53%. The occurrence of relative bradycardia was independent of patient age or gender. There were no differences in median basal temperature or febrile temperature between those patients exhibiting relative bradycardia and those with a normal febrile pulse increase. However, febrile patients with relative bradycardia had a significantly higher resting pulse rate following recovery from infection than did patients who had a normal pulse increase during their illness. These data demonstrate that relative bradycardia frequently accompanies mild infection with O. tsutsugamushi and that baseline cardiovascular parameters may affect the febrile heart rate response to scrub typhus.

Adolescent↗
PubMed1990

Molecular cloning and sequence analysis of the Sta58 major antigen gene of Rickettsia tsutsugamushi: sequence homology and antigenic comparison of Sta58 to the 60-kilodalton family of stress proteins.

The scrub typhus 58-kilodalton (kDa) antigen (Sta58) of Rickettsia tsutsugamushi is a major protein antigen often recognized by humans infected with scrub typhus rickettsiae. A 2.9-kilobase HindIII fragment containing a complete sta58 gene was cloned in Escherichia coli and found to express the entire Sta58 antigen and a smaller protein with an apparent molecular mass of 11 kDa (Stp11). DNA sequence analysis of the 2.9-kilobase HindIII fragment revealed two adjacent open reading frames encoding proteins of 11 (Stp11) and 60 (Sta58) kDa. Comparisons of deduced amino acid sequences disclosed a high degree of homology between the R. tsutsugamushi proteins Stp11 and Sta58 and the E. coli proteins GroES and GroEL, respectively, and the family of primordial heat shock proteins designated Hsp10 Hsp60. Although the sequence homology between the Sta58 antigen and the Hsp60 protein family is striking, the Sta58 protein appeared to be antigenically distinct among a sample of other bacterial Hsp60 homologs, including the typhus group of rickettsiae. The antigenic uniqueness of the Sta58 antigen indicates that this protein may be a potentially protective antigen and a useful diagnostic reagent for scrub typhus fever.

Amino Acid Sequence↗
PubMed1972

Zoonotic infections in military scout and tracker dogs in Vietnam.

Significant levels of antibodies indicative of a variety of zoonotic infections were demonstrated in sera collected from 64 U.S. military scout and tracker dogs after service in the Republic of Vietnam (RVN). Scrub typhus antibodies were found in 45% of the specimens, melioidosis in 19%, group B arbovirus in 49%, and leptospirosis in 62%. Only 38% of the seropositive reactions for leptospirosis could be related to overseas infections. Tests were conducted on paired sera obtained from 32 of the dogs before service in RVN. Significant increases in titer were demonstrated with scrub typhus, melioidosis, leptospirosis, plague, group B arbovirus, and Rickettsia canada antigens. After 2 to 6 months of service in RVN, 8 of 19 dogs developed antibody titers to at least one of four zoonotic diseases. Only 3 of 45 dogs with 7 or more months of service failed to develop antibodies to one or more of the agents. The serological findings pose questions on the potential epidemiological importance and veterinary significance of scrub typhus, group B arbovirus, leptospirosis, and melioidosis infections in dogs.

Animals↗
PubMed1993

Pathologic study of mice infected with Rickettsia tsutsugamushi R19 strain.

Scrub typhus, an acute febrile infectious disease caused by R. tsutsugamushi, has been reported from various parts of the far east and pacific rim of Asia including Korea. It is well known that all human pathogenic rickettsia share an affinity to endothelial cells of the small blood vessels and evoke vascular inflammation variably associated with a rash, microthrombi, and hemorrhage. We infected the ICR mice by inoculating sublethal doses of R. tsutsugamushi R19 strain intraperitoneally and observed the pathologic changes by time sequence. The histopathologic features of experimentally induced scrub typhus in the mice were generally nonspecific interstitial inflammations characterized by interstitial pneumonitis, periportal inflammation, multifocal hepatic necrosis, interstitial nephritis, sinusoidal engorgement, and lymphohistiocytic cell infiltration in lymph nodes and spleen. Contrary to the general features of other rickettsial diseases, the pathologic process of scrub typhus experimentally induced by R. tsutsugamushi R19 strain mainly involved the interstitial connective tissue but not the blood vessels.

Animals↗
PubMed2002

The use of the indirect immunoperoxidase test for the serodiagnosis of rickettsial diseases in Malaysia.

The indirect immunoperoxidase (HP) test has been used extensively in most government hospitals in Malaysia for the serodiagnosis of scrub typhus, murine typhus and tick typhus during the 1990s. The test was used to determine the IgG and IgM antibody titers in patients' sera for three rickettsial species, ie Orientia tsutsugamushi OT; the causative agent of scrub typhus), Rickettsia typhi (RT; the causative agent of murine typhus), and TT118 spotted fever group rickettsiae (TT; the causative agent of tick typhus). The serological findings obtained from Malaysian hospitals using the IIP test (1994-1999) were analyzed. During the six-year period, a total of 61,501 patients' sera were tested, of which 9.6%, 10.5%, and 12.9% had antibody (IgG and/or IgM of > or = 1:50) for OT, RT and TT respectively. A total of 8.6%, 9.8%, and 9.7% of sera had IgG antibody of > or = 1:50 for OT, RT, and TT respectively, indicating past infection. A total of 3.4%, 3.8%, and 6.4 % of sera had IgM antibody of > or = 1:50 for OT, RT, and TT respectively, indicating recent infection. A total of 2,986 (4.9%), 1,882 (3.1%), and 1,574 (2.6%) of sera had IgG and/or IgM antibody titers of > or = 1:400 for OT, RT, and TT respectively, suggesting active rickettsial infection. The seropositivity rates of OT, RT and TT varied according to geographical locations. While the seropositivity of OT remained constant during the six-year period, a reduction in the seropositivity of both RT and TT was noted during recent years. The serological findings reflect the endemicity of rickettsial diseases, including tick typhus, and endemic typhus in various parts of Malaysia. Awareness of these diseases by health and medical staff and by the general public is important if the mortality and morbidity associated with scrub typhus, tick typhus, and murine typhus in Malaysia, are to be reduced.

Antibodies, Bacterial↗
PubMedDate not supplied

Antibodies to Orientia tsutsugamushi, Rickettsia typhi and spotted fever group rickettsiae among febrile patients in rural areas of Malaysia.

A serosurvey was conducted in 1995-97 among 1596 febrile patients from 8 health centres in Malaysia for antibodies against Orientia tsutsugamushi (OT), Rickettsia typhi (RT) and TT118 spotted fever group rickettsiae (SFGR) by using an indirect immunoperoxidase assay. A total of 51.4% patients had antibody against at least 1 of those rickettsiae. Antibody to SFGR was most prevalent (42.5%), followed by RT (28.1%) and OT (24.9%). The seroprevalences of antibodies to SFGR, RT or OT alone were 12.4, 3.6 and 4.3%, respectively. Antibodies against more than 1 species of rickettsiae were presence in 31.1% of the patients, suggesting the possibility of co-infection, previous exposures or serological cross-reactivities. Seroprevalence of the various rickettsiae varied according to locality, with SFGR antibodies being the most prevalent in most areas. There was no significant association of prevalence of rickettsial antibody with gender. The seroprevalence of OT, SFGR and RT increased with patient age but an increase of antibody titre with age was not significant. Those working in the agricultural sectors had significantly higher seroprevalence of OT, SFGR and RT than those not related with agricultural activities. Scrub typhus remains a public health problem with an estimated annual attack rate of 18.5%. Tick typhus and murine typhus as shown in this serosurvey appear much more widespread than scrub typhus in this country.

Adolescent↗
PubMed1991

Molecular cloning and sequence analysis of a Rickettsia tsutsugamushi 22 kDa antigen containing B- and T-cell epitopes.

The identification of Rickettsia tsutsugamushi T-cell epitopes is necessary for the characterization of the protective immune response (of which the T-cell response is essential) against scrub typhus rickettsiae. A T-helper cell line derived from R. tsutsugamushi (Karp strain) immune mice reacted with rickettsial protein antigens eluted from the 18-35 kDa region of polyacrylamide gels. Within this region is a 22 kDa protein which is reactive with immune serum. The gene encoding the 22 kDa scrub typhus antigen (sta22) was cloned and expressed in Escherichia coli. Nucleotide sequence analysis of the sta22 gene revealed a potential open reading frame (ORF) in the sta22 sequence encoding a 22 kDa protein. A recombinant 22 kDa protein synthesized in E. coli maxicells was reactive with anti-rickettsial antibodies. The codon usage of the adenine and thymine rich sta22 sequence was similar to other previously sequenced R. tsutsugamushi genes. Computer analysis of the deduced amino acid sequence suggested that the Sta22 protein has several amphipathic regions which may be potential T-cell epitopes. The recombinant Sta22 protein eluted from polyacrylamide gels induced a strong proliferative response from the scrub typhus rickettsiae reactive T-cell line. Recognition of the R. tsutsugamushi Sta22 polypeptide by both cellular and humoral immune mechanisms implicates this antigen as one of potential importance in vaccine development.

Amino Acid Sequence↗