[DDVF aerosols to protect animals from horseflies].
Explore the source record for details and available documents.
SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
As part of a study of visceral leishmaniasis in the Cévennes in southern France, an infection was transmitted from dog to dog by the bite of a single sandfly, Phlebotomus ariasi Tonnoir, 1921. The role of this species as a vector, suspected from earlier studies, is, therefore, confirmed. Twenty female sandflies, which had engorged on a naturally infected dog 23 +/- 2 days previously were put with a healthy dog which, after an incubation period of 15 months, developed viscero-cutaneous leishmaniasis. In dissections of the sandflies immediately after contact with the experimental dog, it was found that only one had engorged. All of 17 sandflies dissected had midgut infections: 10 of these also had infections in the pharynx. The engorged specimen additionally had parasites in the proboscis, a condition thought by many workers to be necessary for the parasite to be transmitted by bite.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The history and structure of the WHO Onchocerciasis Control Programme in the Volta River Basin are described. An outline of the vector control operations is given, and the techniques and organisation of the entomological evaluation network are described in detail. During the course of the evaluation and related studies undertaken between November 1974 and October 1978 almost 1.2 million S. damnosum females have been taken in over 52,000 man days of catching, and 674,000 flies were dissected. An assessment based on this effort using Annual Biting Rates and Annual Transmission Potentials shows that the transmission of O. volvulus has been reduced to below a defined maximum permissible level over most of the central part of the Programme Area. The difficulties encountered in the remainder, and at certain problem sites are outlined and relevant data given. The benefits to be expected from extending the area further southwards and the possibilities of later reductions in control activity are discussed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The aerial larvicidng operation of the Onchocerciasis Control Programme of the World Health Organization which began in February 1975 resulted in a sharp reduction in Simulium damnosum numbers. However, at the onset of the rainy season the fly population increased in certain areas. Detailed surveys both on the ground and by helicopter did not reveal any significant failures of treatments that could account for the fly densities observed, and it was concluded that the flies must originate from sources outside the controlled zone. This reinvasion proved to be an annual occurrence which has been studied in detail between 1975 and 1978 in the south-western parts of the control zone. The methods used included full day catches by vector collectors carried out every day throughout the season, cytotaxonomic determination of larvae, detailed morphological examination of reared and biting adults and treatment of suspected source rivers with insecticide. The results indicate that the invasion takes place in a SW-NE direction across country for distances of 300 km or more along the track of the monsoon winds. It involves mainly the savanna cytospecies S. damnosum s. str. and S. sirbanum. The invading populations are composed of older parous flies, many of which carry infective 3rd stage larvae indistinguishable from those of Onchocerca volvulus. These females tend to bite close to the rivers and do not disperse as far as normal populations with a higher proportion of younger flies.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Experiments were conducted to examine the dynamics of Cache Valley virus in Culiseta inornata, the probable chief vector of the virus. Of about 1500 laboratory reared C. inornata exposed to viraemic suckling mice, 72 took a blood meal. A relatively high precentage (93%) of the latter mosquitoes became infected. The virus increased more than 100-fold in the experimentally infected mosquitoes. The increasing viral titres were noticed after 7 days and after 15 days. Peak titres averaged 105.0 (mean suckling mouse intracerebral lethal dose) SMICLD50/0.02 mL. The infected mosquitoes had peak titres until at least 35 days after the mosquitoes ingested blood from infected suckling mice. A single trasmission of virus by bite occurred 30 days after the viraemic blood meal. Transovarial transmission was demonstrated. In two experiments, 3.3 and 2.9% of infected mosquitoes transovarially transmitted Cache Valley virus to both male and female progeny. The minimum infection rate for the progeny was 2.05/1000 mosquitoes. This is the first reported experimental demonstration of transovarian transmission in a species of mosquito which overwinters as an adult. The role of transovarian transmission in the natural maintenance of Cache Valley virus remains undetermined.
We present a case of clear cell acanthoma localized on inferior third of the external portion of the left leg, the evolution was of one and a half year, with previous insect bites on the area. We insist on the histologic appearance, characterized by hyperplasia of epithelial cells, intercellular bridges, and presence of acidophilic hyalins intracytoplasmiques. Nous postulons la possibility of a viral etiology, transmitted by insect bite, of an epidermotropal virus.
During 1979 the aerial larviciding operations of the Onchocerciasis Control Programme were extended southwestwards to cover those areas with Ivory Coast where the savanna cytospecies of the Simulium damnosum complex were known to breed. This resulted in a marked reduction of the reinvasion which threatened the Programme in Ivory Coast and Upper Volta in earlier years. Previous conclusions concerning the location of sources of invading populations and consequently the direction and distance of the movements of flies were substantiated. It was confirmed that S. damnosum s. str. and S. sirbanum were the main migrant species. In this area S. Squamosum was shown to be of much less importance as a migratory vector.
Explore the source record for details and available documents.