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At least 793 records · Page 44Linked to original sources
PubMed1969

Ortho-isopropoxphenyl methylcarbamate (OMS-33) as a residual spray for control of anopheline mosquitos. With special reference to its evaluation in the WHO programme for evaluating and testing new insecticides.

More than 1300 compounds have so far been included in the WHO Programme for Evaluating and Testing New Insecticides, which is designed to disclose compounds that may satisfactorily replace those to which insect vectors of disease have become resistant. The authors describe the successful passage of o-isopropoxyphenyl methylcarbamate (OMS-33) through the first 6 stages of the 7-stage programme that has been established for compounds intended for use against anopheline mosquitos and conclude that this product is suitable for testing in the final stage-large-scale epidemiological evaluation.In operational field trials (at 2 g/m(2)) OMS-33 has been shown capable of controlling Anopheles stephensi (in Iran), An. gambiae and An. funestus (in Nigeria) for 3-4 months, An. albimanus (in El Salvador) for 2-4 months and An. dthali (in Iran) for 2(1/2) months. It has an airborne effect by which anophelines are killed for a considerable time after OMS-33 has been sprayed, even though they do not make contact with a sprayed surface; this quality would appear advantageous in areas where anophelines enter houses and bite man but do not rest long enough on sprayed surfaces to acquire a lethal dose of insecticide or where significant outdoor biting occurs. The observance of simple safety precautions protects occupants of sprayed houses, spraymen and others from danger. Chemical studies have indicated that commercially produced water-dispersible powders of OMS-33 are stable under field conditions of storage and use.

Aerosols↗
PubMed1983

[Clear cell acanthoma].

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.

Animals↗
PubMed1981

Influence of organ extracts of Triatoma infestans on differentiation of Trypanosoma cruzi.

The influence that extracts of different T. infestans organs possess to induce Trypanosoma cruzi differentiation from epimastigotes to metacyclic forms in Grace's and modified Grace's media was analyzed. Growth of epimastigotes was adequate in Grace's medium when homogenates of stomach, testes, and ovaries from recently fed insects were added. Growth of epimastigotes was adequate when testes or ovaries obtained from recently fed triatomes were added to modified Grace's medium. Similar results were obtained in Grace's or modified Grace's media supplemented with stomach or intestinal homogenates obtained from "starved" triatomes. None of the above culture conditions induced differentiation of epimastigotes to the metacyclic stage. When extracts of intestine or stomach obtained from triatomes fed 24 to 48 hr previously were used to supplement the modified Grace's medium, growth and differentiation to the metacyclic stage was induced in a high percentage of the population. When extracts of intestine obtained from recently fed insects were used to supplement Grace's medium, differentiation and growth was an in modified Grace's medium. No important differences were observed if cultures were prepared at pH 6.4 or 7.0. The triatome food source did not seem to be important for the differentiation. The parasite population after differentiation to metacyclic type forms showed a higher degree of infectivity than the original population constituted mostly by epimastigotes. These studies suggest the importance of factors from the insect vector in differentiation of T. cruzi.

Animals↗
PubMed1980

New aspects on cutaneous leishmaniasis.

Cutaneous Leishmaniasis today is still a persistent health problem in most parts of the world even in the nonendemic countries. In the first part of this work the general aspects of the disease are considered such as, the organism, the reservoir, the insect vector and the mode of transmission. Epidemiological data including the author's personal observations follow. The traditional clinical classification is mentioned as well as the "new aspects" of the clinical classification by the author as results from his histological investigation. The main points of this classification could be summarized as follows: a) The histologically characterized as granulomatous phase of this disease corresponds clinically to the papular-nodular ulcerated lesions (Acute Leishmaniasis). b) The histologically microtuberculoid phase corresponds clinically to chronic cutaneous Leishmaniasis. c) The Lupus vulgaris-like histological picture, corresponds clinically to the recidivans or late form of Cutaneous Leishmaniasis. This classification is conventional with several clinical criteria. Furthermore, immunology treatment and control of this disease are discussed.

Age Factors↗
PubMed1994

Evaluation of the Chagas' disease vector control program in Minas Gerais, Brazil, with special reference to Triatoma sordida.

As of 1979, data gathered by the Chagas' Disease Control Program (CDCP) in the Brazilian state of Minas Gerais indicated that Triatoma infestans was the Chagas' disease vector most commonly found in and around human dwellings. A decade later, however, this picture had changed, presumably as a result of control efforts; few specimens of T. infestans were collected; and Triatoma sordida had become the most commonly collected vector insect. The aim of the work reported here was to assess the effectiveness of the CDCP in Minas Gerais in 1979-1989, with special reference to T. sordida. For this purpose, 1979-1989 triatomine collection data were reviewed for the two Minas Gerais health districts (Montes Claros and Uberaba) believed to have the heaviest T. sordida infestations. In addition, 1987 data from a serologic survey for human Trypanosoma cruzi infections in seven municipalities of these regions were compared with earlier (1978) serologic data from the same locales. In general, the triatomine collection data documented the precipitous decline of T. infestans in and around human dwellings. They also indicated that while the T. sordida collections had remained stable (in Uberaba) or increased markedly (in Montes Claros), there had been no great upsurge in the numbers of T. sordida collected inside dwellings. It was concluded that control measures were preventing extensive house reinfestations in both Montes Claros and Uberaba; that the situation in Uberaba was relatively stable; and that the marked increase in T. sordida populations around homes in Montes Claros was associated with forest clearing and changing settlement patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Characterization of GDP-alpha-D-arabinopyranose, the precursor of D-Arap in Leishmania major lipophosphoglycan.

Protozoan parasites of the genus Leishmania synthesize a complex lipophosphoglycan (LPG), which is the major cell surface macromolecule. The LPG from Leishmania major contains beta-D-Arap-terminating side chains that are involved in regulating the attachment of the parasite to the midgut epithelium of its insect vector. An arabinose sugar nucleotide donor was identified in soluble extracts of L. major promastigotes. This sugar nucleotide was biosynthetically labeled with D-[2-3H]Glc and with D-[5-3H]Ara. The labeled sugar nucleotide generated [3H]Ara and GDP after mild acid hydrolysis. The absolute configuration of the arabinose was determined after reduction and acylation with a pure enantiomer of Mosher's acid chloride. The pyranose ring configuration was inferred from the ability of GDP-Ara to form borate complexes, and the anomeric configuration was deduced from the results of mild base hydrolysis experiments. Taken together these data suggest that the sugar nucleotide has the structure GDP-alpha-D-Arap. This sugar nucleotide has not been previously described from natural sources and may be unique to trypanosomatid protozoan parasites. Ara-1-PO4 and GDP-Ara were the only soluble metabolites labeled with [3H]Ara, and pulse-chase experiment data are consistent with them being precursors of the arabinosyl residues of LPG.

Animals↗
PubMed1995

From asps to allegations: biological warfare in history.

Biological warfare has been waged intermittently for nearly 2,500 years. The techniques of delivery and weaponization of biological warfare agents have gradually evolved from the catapulting of plague victims to the deliberate use of infected clothes, insect vectors, and specialized weapon systems. Despite advances in immunotherapy and chemotherapy, the threat of biological warfare is increasing, and military health personnel should be acquainted with this area. This paper reviews the history, often controversial, of biological warfare from the Scythian archers through the Russian offensive program in 1994.

Animals↗
PubMed1996

Zoonotic diseases in Canada: an interdisciplinary challenge.

Although zoonotic diseases are generally rare in Canada, a wide range of pathogens can be transmitted from animal reservoirs to humans through insect vectors or direct contact with wild and domestic animals. Across the country researchers with backgrounds ranging from wildlife biology to parasitology and epidemiology are tracking a variety of zoonotic diseases, some of which are causing increasing concern among public health officials.

Animals↗
PubMed1997

Non-cultivable phytopathogenic mycoplasmas: characterization, detection and perspectives for control.

Phytoplasmas (ex MLOs) and spiroplasmas are important groups of plant pathogenic mollicutes, discovered in 1967 and 1970 respectively. Spiroplasmas, like other mollicutes, can be cultured in artificial media and are thus well characterized. On the contrary, phytoplasmas have resisted in vitro cultivation and their study was difficult until the recent development of molecular techniques. From the sequence of their 16S rDNA, phytoplasmas have been shown to be true mollicutes. Fourteen phytoplasma subclasses have been defined, but only two phytoplasmas have so far been named at the genus and species level. Monoclonal antibodies, DNA probes and PCR primers for the specific detection of various phytoplasmas have been obtained. These showed that a given phytoplasma can infect a broad range of plants, while others are restricted to a single plant species. Specific reagents are also used for identification of insect vectors and reservoir plants of the various phytoplasmas. Plant pathogenic mollicutes cannot be controlled chemically today, since the use of antibiotic treatment is forbidden in agriculture. However, the growth and metabolism of mollicutes are known to be inhibited by antibodies and this provides a hopeful approach for future control of these agents in plants. Indeed, it has been shown recently that plants can be engineered to express and assemble functional immunoglobulin chains. Transgenic tobacco plants expressing an antibody against the stolbur phytoplasmas have been developed. They have now to be challenged with the phytoplasma to determine if they have acquired resistance to this mollicute.

Mycoplasma↗