PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Disease Vectors”

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.

At least 19 recordsLinked to original sources
PubMedDate not supplied

[The chemical control of disease vectors. Evaluation of new insecticides. Operational insecticides. New insecticides (author's transl)].

The chemical control of disease vectors which has been very successful during about 15 years is now faced with some difficulties due to the resistance of insects to the insecticides, to the decreasing number of candidate insecticides, to the increase of their price and to the legal restrictions concerning their safe use and their environmental inocuity. Since 1960, W.H.O. has carried out an evaluation programme to define the properties of new insecticides and to access their usefulness for public health. Through this programme several alternative insecticides have been selected and are now used in vector control operations. Although research continues on organophosphorous compounds and carbamates, it also includes the promising groups of pyrethroids and insect growth regulators. The present trend of vector control is to integrate various control techniques and to limit the use of insecticides to the control of the epidemiologically dangerous part of the vector population. This approach might prevent or delay the development of resistance.

Animals↗
PubMed1979

Domiciliary biting frequency and blood ingestion of the Chagas's disease vector Rhodnius prolixus Ståhl (Hemiptera: Reduviidae), in Venezuela.

Demolition of a rural house in the State of Cojedes, Venezuela, provided a collection of 7.934 Rhodnius prolixus of which a random sample of 1,415 was weighed within 48 hours. The field weights, coupled with laboratory information of weight loss (in %) with time, average blood ingestion and meal size sufficient to promote moulting, were used to estimate biting rate under domiciliary conditions. The results show that in this particularly highly infested house, the R. prolixus population bites, on the average, at a rate of 58 times/person/day, draining blood at a rate of about 100 cm3/person/month; this meant a total of 1.2 litres/month from the 11 people inhabiting the house. It was found that the more advanced R. prolixus is in its development, the more aggressive it is in securing its meal: 15, 25, 30, 59 and 77% of fed insects of instar 1 through 5, respectively, were able to achieve moulting with only one meal. Applying the estimated biting rate to R. prolixus collections of other 13 demolished houses, with more typical insect population densities, an average biting rate of 9 bites/person/day was obtained; this value was, however, extremely variable, ranging from 0.2 bites/person/day (once every five days) to 33 bites/person/day.

Animals↗
PubMed2026

Genomic and evolutionary basis of parthenogenesis in a disease-vector tick species.

Haemaphysalis longicornis is an important tick species and pathogen vector characterized by the co-circulation of triploid parthenogenetic and diploid bisexual strains. However, the evolutionary basis of parthenogenesis in this species is unclear. Here we report reference-quality, haplotype-resolved genome assemblies of the parthenogenetic strain and two reference-quality genomes of the bisexual strains. Comparative genomic analysis revealed high collinearity between the parthenogenetic and bisexual genomes, with a stable chromosomal architecture maintained among the three haplotypes of the parthenogenetic strain. The parthenogenetic H. longicornis genome exhibited a major expansion in cell cycle-related gene families, including the inhibitor of apoptosis protein (IAP) family, but was characterized by a contraction in other gene families. Population resequencing of 179 individuals revealed two distinct subpopulations, with chromosome 7 harbouring high genetic differentiation and several candidate genes probably associated with parthenogenesis. Functional experiments showed that knockdown of the BIRC5 gene, a member of the IAP family, suppressed oviposition in both strains, with the parthenogenetic strain exhibiting milder adverse effects probably due to a stronger transcriptional response. Overall, our results reveal the genomic and evolutionary features associated with polyploid parthenogenesis in H. longicornis.

Animals↗
PubMed1979

Discriminant analysis: a method of identifying foci of vector-borne diseases.

Identification of foci of vector-borne diseases does not require knowledge of exact abundances of vectors and pathogens; rather, a focus is defined by the presence, or some minimal level of abundance, of a vector and pathogen. Stepwise discriminant analysis (DA) was applied to data on free-ranging adult wood ticks (the vector) and to data on isolations of Colorado tick fever virus from small mammals. Trap stations were grouped on the basis of relative abundance of wood ticks for one set of analyses and on the presence or absence of virus for another set of analyses. Additional data consisted of easily measured environmental variables. It is concluded that DA provides a useful tool for analysis of ecosystem structure and an effective means of identifying foci of infection.

Animals↗
PubMed1976

Public health advantages of biological insect controls.

Biological control is not new, it is simply newly appreciated. This renewed appreciation stems from the widespread insecticide treadmill which is largely a product of insecticide disruption of the balance of insect communities. Biological control is a natural phenomenon; the regulation of plant and animal numbers by natural enemies. In this broad sense, biological control is vital to public health because it keeps the myriad insect species from out-competing us. It also has direct public health advantages as where natural enemies are manipulated to control disease vectoring insects. Insecticide distruption of biological control by insecticides and the resulting pesticide treadmill have serious public health implications. One is the increased pesticide load in the environment. The other is the acceleration of pesticide resistance in disease vectoring insects. The treadmill and its associated hazards will not abate so long as chemical control dominates our pest management strategy.

Environmental Health↗
PubMed1976

[Prevalence of the ticks Dermacentor marginatus (Sulzer, 1776) and Dermacentor reticulatus (Fabricius, 1794) and their importance as vectors of diseases in Germany (author's transl)].

From a systematical study of German ticks resulted the occurrence of two tick species of the genus Dermacentor. D. marginatus is found to be widely spread in Southern Germany. Adults of the tick feed mainly on sheep. D. reticulatus is first described from Germany where the tick occurs endemic in a limited forest area on red deer. The two tick species are known from neighbouring countries of Germany in transmitting virus, rickettsiae, bacteriae and protozoa but are not yet well studied in Germany. Geiographical distribution and seasonal occurrence of D. marginatus indicates the role of the tick in the epidemiology of Q fever in Germany.

Animals↗