A preliminary study of the acaricidal activity of clove oil, Eugenia caryophyllus.

Background: The search for more eco-friendly acaricides has prompted testing of medicinal plants from botanical sources.

Objective: To evaluate the eradication of house dust mites (HDM), Dermatophagoides pteronyssinus, by direct contact using the essential clove oil (Eugenia caryophyllus).

Methods: A pilot study was initiated to determine the killing power of clove oil.

Effects of high and low temperatures on development time and mortality of house dust mite eggs.

Hatching of Dermatophagoides pteronyssinus eggs was investigated when exposed to temperatures ranging from -70 to +70°C, at varying degrees of humidity (dry and wet heat, direct sunlight) and lengths of time (seven intervals, ranging from 0.5 to 5 h). Exposure to cold was induced using a domestic refrigerator at 4°C, its freezing compartment at -10°C and a deep freezer at -20, -40 and -70°C.

The accumulation of dust mite allergens on mattresses made of different kinds of materials.

Background: Different mattress materials may affect the accumulation of allergens.

Objective: To compare the amount of group 1 dust mite allergens (Der p1 + Der f1) on mattresses made of different kinds of materials before and after use.

Methods: Sixty new mattresses made of kapok, synthetic fiber, coconut fiber and sponge-like polyurethane, were placed in the house officers' dormitory at Siriraj hospital, Thailand.

Effect of helminthic infections together with mite allergen exposure on the risk of wheeze in preschool children.

Although some studies have indicated that helminthic infections and house dust mite exposure may have an alleviating effect on wheeze, an interaction effect of both risk factors has not been examined in Thailand. The objective of this study was to investigate whether exposure to helminthic infections together with house dust mite allergen was associated with wheeze in children aged 18-36 months, living in an area of southem Thailand where helminthic infections are endemic. This study was undertaken as a part of The Prospective Cohort Study of Thai Children which recruited 1,076 children born between December 2000 and November 2001.

Mite penetration of different types of material claimed as mite proof by the Siriraj chamber method.

Background: There are different materials and principles used in the construction of bed encasings. Although these covers claim to have antimite properties, they might not be mite proof.

Objective: This study evaluated the effectiveness of mite penetration of these covers by using the Siriraj chamber method.

Efficacy of various synthetic pyrethroid-impregnated encasement materials against house dust mite under laboratory conditions.

The acaricidal activity of synthetic pyrethroid and benzyl benzoate against Dermatophagoides pteronyssinus was examined in the laboratory, using a specially designed test set up. On the basis of median lethal dose (LD50) values, the compound found to be most toxic to D. pteronyssinus was benzyl benzoate (LD50 = 50 mg/m2), followed by permethrin (LD50 = 76.

Acaricidal daphnane diterpenoids from Trigonostemon reidioides (KURZ) CRAIB roots.

A new daphnane diterpenoid, rediocide F (1), was isolated together with three known compounds, rediocides A (2), C (3) and E (4), from the hexane extract of Trigonostemon reidioides roots by bioassay-guided fractionation for acaricidal activity on Dermatophagoides pteronyssinus, Thai common house dust mite. The structure of rediocide F (1) was established as the demethyl analog of rediocide C (3) on the basis of spectral analysis. Compounds 1-4 exhibited potent activity against D.

The levels of cockroach allergen in relation to cockroach species and allergic diseases in Thai patients.

Unlabelled: Recently, cockroaches have been established as the second most Important allergen, producing allergic diseases, especially in low socioeconomic populations. In Thailand, about 44-61% of atopic patients were positive to cockroach extract by a skin-prick test. This study examined cockroach allergen levels in relation to cockroach species and allergic diseases in the houses of cockroach-sensitive patients.

Cockroach allergen detection and cockroach allergens of allergic Thai patients.

Hybridomas secreting monoclonal antibodies (MAb) specific to American cockroach (Periplaneta americana) were produced through a fusion of immune splenocytes of a BALB/c mouse immunized with crude cockroach (CR) extract and mouse myeloma cells. Two hybridomas namely 38G6 and 3C2 were established. These specific hybridomas secreted IgG1 monoclonal immunoglobulins with antigenic specificities to CR protein components of over 207 to 72 kDa and 45 to 40 kDa, respectively.