Biomedical subjects

J W Maunder

Publications and source records attributed to J W Maunder.

18 recordsLinked to original sources

PubMed2000

A randomized trial of dehumidification in the control of house dust mite.

BACKGROUND: House dust mites (HDM) are sensitive to humidity. Few studies have adequately examined the potential of dehumidification in reducing HDM numbers. OBJECTIVE: The study examined the effect of portable domestic dehumidifiers, and a behavioural programme to reduce humidity, on HDM counts and HDM allergen levels. METHODS: A randomized controlled trial was undertaken. A total of 76 homes were allocated to three groups that received a portable domestic dehumidifier, a behavioural programme, or no intervention. Humidity, temperature, HDM counts (trap and vacuum samples), HDM allergen, and other details of the home environment were measured on four occasions over a period of 1 year. Interventions and measurements were concerned predominantly with one bedroom. RESULTS: There was a reduction in relative humidity in the dehumidifier group, but not the behavioural group. A decline in HDM trap counts was observed for all three groups. Change scores did not indicate that the dehumidifier group had a greater decline than the other groups. A secondary analysis examining presence or absence of HDM showed a shift from households having HDM at baseline to households not having HDM in the final round for some trap measures. Change score analysis indicated that this shift was greater in the dehumidifier group compared with other groups. The dehumidifier group did not show a greater decline in HDM allergen than that seen in the other two groups. CONCLUSION: Neither the dehumidifier nor the behavioural intervention had a major effect on HDM counts or allergen levels. However, the study did have a number of limitations relating to size, timing of intervention, and running of the dehumidifiers. The secondary data analysis may indicate some effect of dehumidification, but clearly this effect was small. There is a need for more information on the effects of reducing ambient humidity on the distribution of HDM within their habitats.

Animals↗

PubMed1998

Lice and scabies. Myths and reality.

Scabies mites are only distantly related to human lice. Nevertheless, the two groups have much in common as regards to structure and life-style. These similarities result from the two groups using parallel adaptations in order to solve some of the problems of being parasites. Understanding these adaptations may help us give better advice.

Adaptation, Physiological↗

PubMed1994

Humidity regulation in the management of asthma patients sensitized to house dust mites.

Substances in the faeces of house dust mites are well-recognized as common allergens in the pathogenesis of asthma. There have been many trials of interventions aimed at reducing mite populations in the home, but most have been uncontrolled, too small, or too short to determine with confidence any beneficial effects. Of those which succeeded, very few used methods which reduced mite populations on a permanent basis. House dust mites are sensitive to humidity. Their geographical distribution is closely correlated to the availability of moisture. Very little work has been done on the effects of reducing humidity in the home environment in the long term, with a view to controlling dust mite populations. Two different methods which might reduce humidities to levels which could successfully reduce dust mite numbers are dehumidifiers, and mechanical ventilation with heat recovery (MVHR). To date there has been no work assessing the effectiveness of dehumidifiers and very little (although promising) work on MVHR. We discuss the potential of humidity control as an adjunct to the clinical treatment of asthma.

Animals↗

PubMed1993

Arena tests with piperonal, a new louse repellent.

Piperonal, once used to kill lice in Australian hospitals, was acclaimed as an effective pediculicide (Corlette, 1925) by the standards of the day. It is unusual in also exhibiting a repellent action against lice, a property only recently realised. A new, easy to use, low-fragrance, pump action spray, which incorporates 2% piperonal, was tested in the laboratory using clothing lice in an arena test and was found to exhibit consistently high repellency after half an hour, dropping only slightly after 24 hours. A well known multi-purpose insect repellent, diethyltoluamide (DEET), was then tested against piperonal. A 2% solution of piperonal was found to be almost twice as effective as a 50% solution of DEET. In arena tests using lice with the tip segments of both antennae removed, no behavioural differences or statistically significant differences from a random distribution could be found between untreated and Rappell-treated areas. This strongly suggests that sense organ(s) on the tip of the antenna are necessary for detection of the repellent. Although there can be no strict correlation between results in the laboratory and potential efficacy in the field, materials such as insecticides found to be effective in the laboratory have been found to be equally effective in the field. Furthermore, what with the threat of resistance to head lice insecticides, ineffectual treatment and the lack of contact tracing, a repellent would be of obvious use in the control of head lice.

Animals↗

PubMed1993