RESUMO
In January 1959 the malaria control programme in Trinidad was changed to a malaria eradication programme. This is scheduled to end in December 1961 and there is every indication that malaria eradication will be accomplished on schedule. DDT has been used since 1945 and while A. aquasalis, the malaria vector of the coastal regions has shown no signs of resistance, several house hold pests, particularly culex fatigans, have developed resistance to DDT and dieldrin, malathion, gammexane and sevin. In order to keep the goodwill of the housewife and thereby enable the residual spraying programme to run smoothly it was decided to investigate the effect of Baytex. In a control area, 1,247 houses were sprayed, of which 1,234 received a deposit of 0.66 gms per square metre and 113 received 1.0 gms per square metre. The results of spraying on C. fatigans and A. aquasalis were evaluated directly by wall testing and indirectly by assessing the fumigant action of Baytex. The effects on other household pests were determined by house visits and absolute mortality on these pests was obtained immediately. Wall test showed diminishing mortality of C. fatigans and A. aquasalis with the passage of time. The fumigant action of Baytex appears to be more lethal in that it has continuous effect over 24 hours in the day compared with the brief effects of actual contact from one hourly direct wall testing technique (AU)
Assuntos
Insetos Vetores , Malária/prevenção & controle , Resistência a Inseticidas , Trinidad e Tobago , DDTRESUMO
A series of laboratory tests were carried out with Baytex on the larvae and adults of Culex fatigans and Aedes aegypti. The results of these tests show that Baytex is highly effective against both these species. A comparatively safe insecticide is now available for any future campaigns against Culex fatigans and a possibility of controlling Bancroftian filaria. The length of residual action has been determined, but the indications are that the insecticide is persistent (AU)
Assuntos
Humanos , 21003 , Inseticidas , Culex , AedesRESUMO
Blood smears for precipitin analysis of freshly fed A. aquasalis the coastal vector of malaria in Trinidad were made in the villages of Laventille and New La Paille during the years 1950-1955. 13,332 smears from New La Paille and 4,590 from Laventille were analysed by the Lister Institute, London. Over 60 percent of the total number of smears made in each village were positive for bovine blood and the next highest percentage being that for equine blood. Precipitin tests revealed that A. aquasalis also feeds on goats, pigs, dogs and fowls. Among the smears, several which could not be identified, were thought to be from wild mammals and mangrove birds. Tests also revealed that A. aquasalis does not confine itself to feeding on a a single animal. It will feed on as many as four different animals. Despite differences in (a) the number of smears (b) the animal population and (c) the character of the two villages Laventille and New La Paille, the percentages of blood smears for the various animals showed some degree of similarity. (AU)
Assuntos
Humanos , Cães , 21003 , Anopheles , Testes de Precipitina/métodos , Vetores de Doenças , Trinidad e Tobago , Malária , Comportamento Alimentar , Cabras , Bovinos , Suínos , Aves Domésticas , CavalosRESUMO
A detailed tree hole survey for Aedes aegypti was carried out in the town of Arima, Trinidad. 8,045 trees were inspected and 63 holes were found with larvae of Aedes aegypti. The height of the positive holes varied from near ground level to 34 feet. Most of the trees found positive were common fruit trees. 25 of the 52 found positive were either breadfruit or chataigne, two varieties of Artocarpus communis, 7 were avocado (Persea americana), and six were golden apple (Spondias cytherea). 55 of the 63 tree holes found positive, i.e. 87 percent, were above the height of the average perifocal sprayer and hence would have escaped the treatment in the normal course of operations. There was light breeding in most of the holes. In a few it was very heavy, e.g. a mango tree hole with 150 larvae and pupae. Also found in 9 tree holes during the course of this work were larvae of Haemagogus spegazzinii. All the tree holes were treated with brickettes of benzene hexachloride in plaster of paris. (AU)
Assuntos
21003 , Aedes/isolamento & purificação , Controle de Mosquitos/métodos , Árvores , Cruzamento , Trinidad e TobagoRESUMO
Laboratory investigations proved what has been suspected from field observations, that resistance to D.D.T. had occurred in Aedes aegypti. Colonies of a local strain of Aedes aegypti were established at a field insectary and at the laboratory and D.D.T. in up to 500 parts per million failed to kill larvae in 48 hours. (AU)