Orientia tsutsugamushi is causative agent of tsutsugamushi disease, they parasitize in mites and is transmited from mother mite to other generation through egg (vertical transmission). In addition, they is transmited from this mite strain to other mite strain (horizontal transmission), this enssure large distribution of Orientia tsutsugamushi in mite community. However, this phenomenon rarely occure in nature. Orientia tsutsugamushi transmit to human through the bite of mites due to some of mite strains
Orientia tsutsugamushi ; Disease Vectors

Background: quality of food hygiene and safety directly affected public health. In Vietnam, after 5 years implementing the programs on ensure food safety, the aspects of food safety had improved significantly; food poisoning had been gradually controlled but still high. Objectives: to access on food poisoning outbreak in first six months of 2006 in Vietnam. Subjectives and Method: a cross sectional and retrospective study on food poisoning outbreak in first six months of 2006. The studied subjectives including: health staffs of provincial preventive centre, staffs in charge of food safety work; documents of food poisoning were stored in VFA. Results: there were 204 outbreaks in 58 provinces with 4.198 victims and 44 deaths or the mortality rate was 1.05%. By causes, percentages of outbreaks, cases and deaths due to bacterial pathogens were 41.7%, 53.4% and 0.0% respectively; due to chemical contamination: 12.7%, 13.0% and 4.5%; due to food denature: 9.3%, 17.2% and 11.4%; and due to natural toxicants: 34.8%, 15.2% and 81.4%, respectively. The number of deaths was highest in North-east and North-west areas (35 cases), in North and South Central coast (5 cases), and in Mekong river data (4 cases). Similarly, the mortality rates in these three regions were 5.0%, 0.49% and 0.27%, respectively. Conclusions: here were 204 outbreaks in 58 provinces with 4.198 victims and 44 deaths. Causes due to bacterial pathogens were the highest, followed by due to natural toxicants. The number of deaths was highest in North-highland.
Foodborne Diseases/epidemiology ;

The study was carried out in an endemic area of tsutsugamushi disease, Taketa city, Japan, from January to December, 2000. Results: 1018 unengorged larvaes of 14 species were isolated from soil and ground surface by direct method and Suzuki method. Among them Helenicula miyagawai was isolated by only the Suzuki method. Leptotrombidium scutellare and l.pallidum suspected as vectors of tsutsugamushi disease in many areas of Japan were detected in this study. The seasonal occurrence of unengorged larvae of L.scutellare was from October to January with the probable peak in November. While L.pallidum occur almost throughout the year with two peak periods, one in May and the other in September.
Scrub Typhus ; Trombiculidae

The study applied the Nested PCR technique with part of 56kilodalton type-specific antigen (TSA) gene DNAs of Orientia tsutsugamushi. Forty-eight pools (480 individuals) of unengorged larvae belonging to 4 trombiculid species: L. scutellare, L. pallidum, L. kistasatoi and L. fuji, collected from soil and ground surface of an endemic area for tsutsugamushi disease, were tested for 56kilodalton type-specific antigen (TSA) gene DNAs of Orientia tsutsugamushi, by nested PCR. Among them, 2 of 13 pools of L. scutellare were positive, and 2 serotypes of Kuroki and Gilliam were identified. Remaining 35 pools of 3 species were negative for Orientia tsutsugamushi. By using epidemiological' analysis, unengorged larvae of L. scutellare was suspected as the vector of tsutsu-gamushi disease in the studied area.
Orientia tsutsugamushi ; Scrub Typhus ; Epidemiology ; Polymerase Chain Reaction