Subject(s)
Cells, Cultured , Humans , Lymphocyte Activation , Scrub Typhus/immunology , Specimen Handling , Tropical ClimateABSTRACT
R. tsutsugamushi strains found in chiggers collected from 3 different sites throughout Thailand were antigenically characterized. Monotypic infections were observed in 76.7% of the chiggers. Karp was the most predominant strain, followed by TA716, TA763, TA686 and Kato. This study represents the first confirmed report of R. tsutsugamushi infection in 8 different chigger species in Thailand.
Subject(s)
Animals , Mites/microbiology , Orientia tsutsugamushi/classification , Serotyping , Thailand , Trombiculidae/microbiologyABSTRACT
L. (L.) deliense was the predominant vector of scrub typhus in a mature oil palm estate, but a small number of L. (L.) fletcheri (0.1% from rodents) and L. (L.) vivericola (0.02% from rodents and 8.0% from black plates) was also collected. Although good correlation between L. (L.) deliense collected from rodents and from black plates was not established, either method may serve as a general indicator of population fluctuations over a period of time. For the most part, the vectors of scrub typhus were limited to litter piles, and thus, the possibility of contracting scrub typhus within this type of habitat was minimal.
Subject(s)
Animals , Arachnid Vectors/physiology , Humans , Mites/physiology , Population Density , Rats/parasitology , Scrub Typhus/transmission , Trees , Trombiculidae/physiologyABSTRACT
An epidemiological study in a mature oil palm estate in Peninsular Malaysia has demonstrated a low prevalence of R. tsutsugamushi infection in small mammals. The direct fluorescent antibody technique for assaying infections in chiggers proved more sensitive than mouse inoculation. Most infections in both chiggers and rodents were caused by the Karp strain.
Subject(s)
Animals , Animals, Wild/immunology , Antibodies, Bacterial/analysis , Disease Vectors , Fluorescent Antibody Technique , Malaysia , Mites/immunology , Orientia tsutsugamushi/immunology , Rodentia/immunology , Scrub Typhus/immunology , Serotyping , Trombiculidae/immunologyABSTRACT
Rickettsia tsutsugamushi organisms were identified in Giemsa and fluorescent antibody stained monocyte cell cultures derived from experimentally infected monkeys and dogs. The identification of organisms in monocyte cell cultures compared favorably with the standard technique of mouse inoculation.
Subject(s)
Animals , Azure Stains , Dogs , Fluorescent Antibody Technique , Haplorhini , Monocytes/microbiology , Orientia tsutsugamushi/isolation & purification , Scrub Typhus/microbiologyABSTRACT
Dog sera, collected from different communities throughout Selangor, Peninsular Malaysia, were investigated for the presence of antibodies to R. tsutsugamushi and R. typhi. Scrub typhus antibodies were present in animals from the rural areas only, whereas murine typhus antibodies were observed in equal numbers of dogs from both rural and metropolitan areas. Greater percentage of dogs from suburban areas had demonstrable antibody titers to murine typhus than from the urban area.
Subject(s)
Animals , Antibodies, Bacterial/analysis , Dog Diseases/epidemiology , Dogs , Fluorescent Antibody Technique/methods , Malaysia , Orientia tsutsugamushi/immunology , Rickettsia typhi/immunology , Scrub Typhus/diagnosis , Typhus, Endemic Flea-Borne/diagnosisABSTRACT
Over 1,200 isolations of R. tsutsugamushi were obtained over 7 generations of L. (L.) arenicola and no reproducible differences in virulence or antigenic markers could be detected among these isolations. The F8 generation yielded rickettsia with the same antigenic makeup and virulence properties as the original female parent mite. When these isolates were inoculated into mice they elicited the same predominant antibody specificities, i.e. they all produced antibody which reacted with the TA 763 and Karp strains. These were the same as the major antigens detected by direct fluorescent antibody staining of the isolates.
Subject(s)
Animals , Antibody Specificity , Antigens, Bacterial , Arachnid Vectors , Mites/microbiology , Orientia tsutsugamushi/immunology , Trombiculidae/microbiology , VirulenceABSTRACT
A high prevalence of murine typhus was found in the human and rodent populations of Senaling, West Malaysia. In addition to 2 index cases which prompted the investigation, 45% of the humans and 35% of the rodents had IFA titers of 1/50 or greater. Serological studies provided evidence of recent infections in 3 human subjects. In a control group of Malaysian soldiers IFA titers of 1/50 or greater were found in only 13 (5%) of 265 sera tested.
Subject(s)
Adolescent , Adult , Animals , Child , Female , Siphonaptera , Humans , Malaysia , Male , Rats , Rodent Diseases/epidemiology , Typhus, Endemic Flea-Borne/epidemiologyABSTRACT
A study of 1,437 unselected febrile patients in rural Malaysia yielded a diagnosis of leptospirosis in 86 (6.0%). The clinical syndrome was mild to moderate in all cases, jaundice was observed in only 2 (2.3%) and no deaths were documented. The diagnosis was not clinically obvious in most cases, and it is apparent that many infections must be going unnoticed at present.
Subject(s)
Fever/etiology , Headache/etiology , Humans , Jaundice/etiology , Leptospirosis/complications , MalaysiaABSTRACT
The passive transfer of convalescent sera did not protect the majority of mice against challenge with the homologous strain and was completely ineffective against challenge with strains unrelated by fluorescent antibody techniques. When the immune sera was incubated with the rickettsia in vitro and then inoculated into the mice a dramatic increase occurred in the number of surviving mice. The importance of these data in relation to published results with other species of rickettsia is discussed.