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PubMed1975

Indirect hemagglutination test for human antibody to typhus and spotted fever group rickettsiae.

An indirect hemagglutination (IHA) test is described that uses glutaraldehyde-stabilized erythrocytes treated with a rickettsial erythrocyte-sensitizing substance obtained from Rickettsia typhi or Rickettsia rickettsii. The serological reagent was stable for at least 3 months at room temperature and 6 months at 4 C. It exhibited group specificity and no group cross-reactivity. At a minimum dilution of 1:40, acute and early convalescent epidemic and murine typhus antisera showed 86% positive reactors, whereas similar spotted fever antisera had 74% positive reactors. In comparison with the indirect fluorescent antibody test, the IHA procedure gave lower titers but showed comparable detection of seroconversion with most paired sera. The IHA test demonstrated significantly higher titers than the complement fixation test and was more sensitive than either the complement fixation or Weil-Felix test in identifying seroconversion. No agglutination was observed when sensitized erythrocytes were tested with rodent sera known to contain rickettsial antibodies.

Agglutination Tests↗
PubMed1992

The reactivity between rickettsiae and Weil-Felix test antigens against sera of rickettsial disease patients.

Of the sera which were positive to Rickettsia tsutsugamushi by indirect immunoperoxidase test, approximately 80% sera were positive to a Proteus OXK antigen by Weil-Felix test at 10 or more days after the onset of fever, while only 10% sera were positive within 9 days from the onset of fever. In ELISA using the OXK antigen, almost all of the paired sera of tsutsugamushi disease (TD) patients increased on the IgM antibody titres with the rise of their titres by Weil-Felix test, whereas the IgG antibody titres of these sera were unrelated with the titres of Weil-Felix test. We suspect that the reactivity of TD patients sera to the OXK antigen in Weil-Felix test was derived from the reactivity of the IgM antibody against the OXK antigen common with R. tsutsugamushi. The patient sera infected with a Japanese isolate of spotted fever group rickettsia (SFGR) cross-reacted with the Thai Tick Typhus (TTT) strain of SFGR by indirect immunoperoxidase test. In Weil-Felix test, the reactivity of these sera to OX2 antigen were higher than that to OX19 antigen, like the sera infected with other SFGR, except of R. rickettsii. These sera also reacted with TTT and OX2 antigens by ELISA. The titres of IgM antibody against OX2 antigen in the sera in ELISA were in parallel with the titres of the sera against OX2 antigen in Weil-Felix test, but not the titres of IgG antibody. We suggest that the reactivity of the patient sera infected with SFGR to OX2 antigen of Weil-Felix test is dependent on the IgM antibody.

Antigens, Bacterial↗
PubMed1993

Chemical properties of lipopolysaccharides from spotted fever group rickettsiae and their common antigenicity with lipopolysaccharides from Proteus species.

The lipopolysaccharides (LPS) isolated from spotted fever group (SFG) rickettsia strains Thai tick typhus TT-118 and Katayama were characterized by chemical analyses, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, enzyme-linked immunosorbent assay (ELISA), and immunoblotting. These LPS did not contain heptose, but they contained 3-deoxy-D-manno-octulosonic acid (KDO), glucosamine, quinovosamine, phosphate, ribose, an unknown neutral sugar, and palmitic acid. Resolution of the apparent molecular masses of these LPS by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and staining with silver showed ladder-like bands. In an ELISA, convalescent-phase sera from 10 patients with Japanese spotted fever reacted with LPS from the Katayama strain, and 90% (9 of 10) of these sera also reacted with LPS isolated from Proteus vulgaris OX2. Immunoblotting revealed that the sera reacted with the high-molecular-mass bands of LPS from SFG rickettsiae, in addition to those of OX2 LPS. In an ELISA, immunoglobulin M antibodies from these sera reacted with the O-polysaccharide and lipid A portions of LPS from P. vulgaris OX2. The epitopes common to LPS of SFG rickettsiae and P. vulgaris OX2 may be in the O-polysaccharide and lipid A portions.

Antibodies, Bacterial↗
PubMed2003

Emerging rickettsial infections in Sri Lanka: the pattern in the hilly Central Province.

OBJECTIVES: To identify different rickettsial infections using a specific immunofluorescent technique in patients clinically diagnosed as 'typhus fever' in the Central Province of Sri Lanka, and to define the clinical picture, assess the severity of infection and to determine the pattern of geographical distribution of the infections of the hospital-based patients. METHODS: A specific indirect immunofluorescent antibody technique was used on the sera of two groups of patients in laboratories in Japan and Thailand. RESULTS: We serodiagnosed infections with Orientia tsutsugamushi, Rickettsia typhi and spotted fever group in 56 of 118 clinically investigated patients. There were eight infections with O. tsutsugamushi, two with R. typhi and 10 spotted fever group patients with IgM antibodies suggestive of acute infection. Nineteen patients had antibodies against these three rickettsial species, suggestive of past exposure, co-infection or cross-reactivity of antigens. Discrete, erythematous maculopapular rash was common to all three types of infection except for five patients who had no rash. Five patients positive for spotted fever antibodies developed fern-leaf type skin necrosis with severe illness. Duration of the febrile period ranged from 4 to 23 days with defervescence occurring after specific antibiotic treatment. CONCLUSIONS: The study has shown the presence of different types of rickettsial infections in the Central Province of Sri Lanka. The characterization of the clinical picture and the severity of infection provide useful information for the proper management of the patients in the future.

Adult↗
PubMed1984

Macrophages in resistance to rickettsial infections: protection against lethal Rickettsia tsutsugamushi infections by treatment of mice with macrophage-activating agents.

Peritoneal macrophages of BALB/c and C3H/HeN mice activated in vivo by intraperitoneal inoculation of viable Mycobacterium bovis strain BCG or the nonliving macrophage-activating agent Propionibacterium acnes (Corynebacterium parvum), were resistant to infection with Rickettsia tsutsugamushi, and they killed bacteria that did gain entry into the intracellular environment of these cells. This macrophage resistance to infection and intracellular destruction of rickettsiae was dependent upon development of an immune response to the activating agents, since macrophages elicited by sterile inflammatory agents failed to display either microbicidal activity unless cells were exposed to factors present in lymphokine-rich culture fluids from antigen or mitogen stimulated spleen cells (LK) in vitro. C3H/HeN mice that had been treated with activating agents, but not sterile inflammatory irritants, also survived intraperitoneal inoculation of up to 10(4) R. tsutsugamushi. This nonspecific protection required the chronic presence of activated macrophages: acute immune response induced by intraperitoneal injection of PPD into mice inoculated intradermally with BCG, or intraperitoneal inoculation of conconavalin A, were not sufficient to induce survival of rickettsial disease, although macrophages from these animals were activated to kill rickettsiae at the time of challenge. The critical nature of activated macrophages in nonspecific protection against rickettsial infection was demonstrated with the macrophage-defective C3H/HeJ mice. These mice are equally as susceptible as C3H/HeN mice to intraperitoneal inoculation of R. tsutsugamushi, but do not develop activated macrophages in response to BCG infection, and are not protected against lethal rickettsial challenge following BCG treatment.

Animals↗
PubMed1982

Sero-epidemiological survey of Rickettsia tsutsugamushi infection in a rural Thai village.

A sero-epidemiological survey of a rural Thai village demonstrated a 77% prevalence of antibody against Rickettsia tsutsugamushi in adults. Acquisition of antibody occurred very early in life, especially in females, but the prevalence of antibody in the adult population showed no statistically significant sexual distinction. Antibody against all three prototype strains was present in Thailand but antibody titres did not vary by strain type or the age of the individual.

Adolescent↗
PubMed1983

Development of antibody to Rickettsia tsutsugamushi in soldiers in Malaysia.

Malaysian, British and New Zealand soldiers were tested for evidence of infection with Rickettsia tsutsugamushi after several weeks' exposure to the infection during field exercises in Malaysia. 39 (5.0%) of 787 British and New Zealand soldiers developed immunofluorescent antibody (IFA) to R. tsutsugamushi to a titre of 1:50 and two (0.3%) to a titre of 1:100. 11 (1.5%) of 751 Malaysian soldiers also developed low titres less than or equal to 1:100. These low antibody levels were not correlated with clinical disease, and their significance is unknown. Seven (0.9%) of the Malaysians showed an IFA rise to greater than or equal to 1:200, and three of these experienced febrile illnesses, one lasting two weeks. An additional eight Malaysian soldiers had an IFA titre of greater than or equal to 1:400 when first tested and six of these also had a Proteus OXK agglutinin titre of greater than or equal to 1:160, indicating infection shortly before the study.

Antibodies, Bacterial↗
PubMed2005

Survival of two Orientia tsutsugamushi bacterial strains that infect mouse macrophages with varying degrees of virulence.

Orientia tsutsugamushi, an intracellular parasitic bacterium, comprises numerous strains of differing virulence. When BALB/c mice were infected intraperitoneally with this pathogen, a virulent strain known as Karp was found to multiply in the intraperitoneal macrophages and kill the mouse. In contrast, an avirulent strain, Kuroki, was shown to invade macrophages but be eliminated from the cells, allowing mouse survival. O. tsutsugamushi invades its host cell cytoplasm through phagocytosis and disruption of phagosomal membranes but some bacteria are then killed by phago-lysosomes within 1h of infection. Microscopic observations could not differentiate the Karp and Kuroki strains during entry and subsequent cell killing by phago-lysosomes. However, the Kuroki cells failed to divide and were markedly deformed following cytoplasmic invasion at several days post-infection. These findings suggest that macrophages have a mechanism to eliminate O. tsutsugamushi in the cytoplasm, if the invading bacteria escape phagosomal clearance, and that it is this mechanism that Kuroki does not survive. Additionally, significant levels of nitric oxide (NO) are produced in macrophages by Kuroki, but not by Karp. An NO synthase inhibitor, however, does not increase the growth of Kuroki, suggesting that NO is induced in a strain-dependent manner but does not effect proliferation.

Animals↗
PubMed2000

Development and persistence of antibodies to Orientia tsutsugamushi in the roof rat, Rattus rattus and laboratory mice following attachment of naturally infected Leptotrombidium deliense.

The development and persistence of antibodies to Orientia tsutsugamushi in Rattus rattus and laboratory mice following infection from the bite of naturally infected Leptotrombidium deliense is reported. Antibodies in R. rattus were first detected using an indirect immunoperoxidase method 2 weeks after attachment of an infected mite. The IgM antibody response was mild, and was detected 2, 4 and 6 weeks after infection, while the IgG response was stronger and was detected from 2 to 19 weeks after infection, when the tests ceased. Active rickettsiae were isolated from R. rattus 1-8 weeks after attachment of infected L. deliense, but rats were not adversely affected by infection and appeared to behave in the same way as uninfected rats. In contrast to rats, laboratory mice were killed by O. tsutsugamushi following infection by attachment of infected L. deliense. The development of antibodies in mice was not detected before gross symptoms of infection were observed. Antibodies were first detected 14 days after attachment of infected mites, when mice were close to death.

Animals↗
PubMedDate not supplied

Branch retinal vein occlusion in the right eye and retinal hemorrhage in the left in a patient with classical Tsutsugamushi disease.

PURPOSE: To report branch retinal vein occlusion and retinal hemorrhages associated with tsutsugamushi disease. METHODS: Case report of a 60-year-old woman who complained of fever, chills, headache, lymphadenopathy, and blurred vision in the right eye following an insect bite to the lower right forehead. RESULTS: Serological findings showed elevated titers for the strains of Rickettsia tsutsugamushi. Ophthalmologic examination disclosed bilateral conjunctival injection, flame-shaped hemorrhage in her right fundus, and scattered hemorrhage in her left fundus. Fluorescein angiography demonstrated dye leakage and dilation of capillaries. CONCLUSIONS: Branch retinal vein occlusion associated with classical tsutsugamushi disease, as demonstrated in our patient, may be rare.

Antibodies, Bacterial↗
PubMedDate not supplied

Conjunctival injection, episcleral vessel dilation, and subconjunctival hemorrhage in patients with new tsutsugamushi disease.

Tsutsugamushi disease is found in two types: classical and new. There have been very few reports describing the ocular findings in patients with the new form. We have described four patients with this type, selected according to their clinical and laboratory findings, including immunofluorescent titers and polymerase chain reaction results. Eyes were examined by standard ophthalmic procedures. Patient 1 had bilateral conjunctival injection and subconjunctival hemorrhage; patients 2-4 had conjunctival injection and episcleral vessel dilation bilaterally. We believe that conjunctival injection is found in most eyes of patients with new tsutsugamushi disease.

Adult↗