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Biomedical subjects

H F SCHOOF

Publications and source records attributed to H F SCHOOF.

At least 19 recordsLinked to original sources
PubMed1965

DICHLORVOS VAPOUR DISINSECTION OF AIRCRAFT.

The authors describe the testing of an automatic aircraft disinsection system permanently installed on a commercial DC-6B passenger aircraft. An air-compressor forces ambient cabin air, partially saturated with dichlorvos vapour at a set concentration, through the cabin, cockpit and baggage compartments of the aircraft for 30 minutes. Insecticide concentrations and insect mortality were observed in post-overhaul check flights, and insect mortality and passenger reactions were observed on scheduled flights between Miami, Florida, and Nassau, Bahamas.The results showed satisfactory biological efficiency. The passengers were unaware of the disinsection process and showed no signs of discomfort.

Aircraft↗
PubMed1963

DICHLORVOS AS A RESIDUAL FUMIGANT IN MUD, PLYWOOD AND BAMBOO HUTS.

In experiments conducted at Savannah, Ga., dichlorvos dispensers of montan (lignite) wax installed at a rate of six units per 1000 cubic feet (28 m(3)) in huts with mud or bamboo walls and with thatched roofs produced kills of caged Anopheles quadrimaculatus (12 hours' exposure) at or above 95% for 5-6 weeks. The doors, windows, and eaves of the huts were open for maximum ventilation. In a non-ventilated plywood hut, a single dispenser gave effective kills for 7 months but in a non-ventilated mud hut the period was 5 months. Air concentrations of dichlorvos in the mud hut were shown to be definitely lower than those in a plywood hut at the same dosage level.

Animals↗
PubMed1963

INITIAL FIELD STUDIES IN UPPER VOLTA WITH DICHLORVOS RESIDUAL FUMIGANT AS A MALARIA ERADICATION TECHNIQUE. 1. GENERAL CONSIDERATIONS.

Laboratory and simulated field tests have shown that dichlorvos, a volatile insecticide, can be prepared in a solid formulation which releases the dichlorvos vapour over a period of several months at a relatively uniform rate high enough to kill adult anopheline mosquitos but low enough to have no effect on man and the higher animals.A field experiment is in progress in Wakara, Upper Volta, to evaluate the residual fumigant technique under practical field conditions. Chemical, biological, toxicological and epidemiological data obtained during the first nine months indicate that the method produced dichlorvos vapours in a concentration effective against mosquitos for 3 to 5 months per treatment, that the occupants of the treated dwellings showed no detectable effects from the insecticidal vapours, and that the malaria rates were reduced by 38%-55% among the population of the treated village as compared with a nearby untreated control village.

Africa↗
PubMed1961

Insecticidal vapours for aircraft disinsection.

A general discussion of the problem of aircraft disinsection is presented. The weaknesses of the present aerosol method, the limitations imposed by airline operators, government officials, passengers, and others, and the potential value of insecticidal vapours as a means of aircraft disinsection are discussed. An apparatus is described for screening insecticides for their vapour toxicity to houseflies and mosquitos. This apparatus led to the discovery of DDVP (O,O-dimethyl-2,2-dichlorovinyl phosphate) and its remarkable vapour toxicity to insects, and to the subsequent studies of its potential use in the vapour state for aircraft disinsection.

Aerosols↗
PubMed1961

Disinsection of aircraft with a mechanical dispenser of DDVP vapour.

In-flight and on-ground tests in commercial aircraft have demonstrated the feasibility of using DDVP (O,O-dimethyl-2,2-dichlorovinyl phosphate) vapour for disinsection purposes. Treatment of the passenger compartments of DC-6 and DC-7 aeroplanes was accomplished by passing cabin air through a fibrous cartridge impregnated with DDVP. The DDVP-charged air stream was distributed from the cartridge into the passenger compartment through small orifices, spaced 3 feet apart, in metal tubing suspended at ceiling height along the longitudinal axis of the cabin. Further distribution of the vapour was effected by the air currents of the ventilating system. During in-flight tests, vapour concentrations of 0.20 and 0.24 mug of DDVP per litre of air gave 100% mortalities of caged houseflies located at 12 sites at three different levels and exposed for 30 minutes. No effect of the vapour was noticed on the cholinesterase levels of three individuals exposed to the treatment during 24 tests.

Aerosols↗
PubMed1961

Field tests on the residual effectiveness of deposits of malathion and Bayer 29493 against resistant Anopheles albimaus in El Salvador.

The appearance of resistance to both dieldrin and DDT in several malaria vectors has intensified investigations on the potential of organophosphorus compounds for residual application. This report describes the final year's activities of a three-year study on malathion. Water-wettable formulations of malathion and of Bayer 29493 were evaluated against DDT/dieldrin-resistant Anopheles albimanus in El Salvador.The results indicate that neither compound at a dosage of 0.5 g/m(2) offers any promise as a residual agent. At dosages of 1.0 g/m(2) or 2.0 g/m(2) the two toxicants gave effective kills (70%-100%) for periods of 21/2-3 months, based on 1-hour exposure to the treated surfaces. Up to 3 months, both compounds gave similar levels of effectiveness on wood, thatch, and mud. On whitewash and plaster surfaces, Bayer 29493 was superior to malathion.The findings indicate that each insecticide has considerable potential value for residual treatment in areas where the malaria vector cannot be killed effectively by either DDT or dieldrin. In such areas, further investigation into their utility as replacements for the chlorinated hydrocarbon insecticides is warranted.

Animals↗