Les moustiques d'intérêt médical

There are about 3 450 species of mosquitoes. The first three stages of the life cycle (egg, larva, pupa) are aquatic. The adult stage, which is 1–12 weeks long, is aerial. This article deals with the biology of mosquitoes. They can be considered as simple pests but they are also transmitters of diseases caused by parasites and arboviruses, particularly in the intertropical area. Their impact on human health is therefore significant. The main vectors are Anopheles, Aedes and Culex species. They can be discriminated quite easily by several morphological aspects that are described here. Anopheles species are transmitters of malaria, filarias and arbovirosis.Aedes and Culex species are vectors of filarias and arbovirosis. There are a few effective vaccines or treatments for these vectorborne diseases. However knowing the periods of activity of each species in order to avoid their bite, using repulsive or insecticide products are the best prevention against all of them.     

Intérêt du séquençage dans le diagnostic virologique : application au VIH et au VHC

Sequencing is an important tool for viral typing and is also used to analyse resistant genotypes. However, in current hospital practice, it is only used for HIV and HCV. In effect, it is important to monitor the genetic diversity of these two viruses as this has implications for diagnosis (antibody and viral genome detection), plasma RNA quantification and therapeutic strategy. Several methods exist for typing or genotyping. The standard method is still nucleotide sequencing followed by phylogenetic analysis. In addition, it is only by sequencing several regions of the genome that recombinant viruses can be identified in certain cases. The introduction of systematic sequencing of resistant HIV in medical virology laboratories will favour data accumulation. The available data have already served to establish decision-making algorithms that need to be continually adapted and updated with evolving knowledge and the appearance of new molecules.     

Intérêt de la biologie moléculaire dans le diagnostic des infections vlrales du système nerveux central

The use of PCR and hybridization for the detection of viral nucleic acids in cerebrospinal fluid (CSF) currently represents the most reliable method for the meningoencephalitis diagnosis due to herpes viruses, enteroviruses, JC polyomavirus and HIV-1 primary infection. The molecular tools are less suitable for the postinfectious encephalitis associated with a systemic viral infection such as neurologic complications of measles, rubella, influenza and varicella, The speed and high sensitivity allow earlier diagnosis and specific treatment. The monitoring of the antiviral therapy is assessed by the development of quantitative amplification assays in CSF or by a negative PCR result. The pattern mutations conferring resistance and the genetic variability of viruses (HIV-1, Dengue virus) could be determined from different locations in the genome. Theses methods performed over the past several years as research tools have now a large scale application with the commercialization of some tests. But before becoming the first line diagnostic test, PCR of CSF could be conducted with control quality and evaluated protocols for avoiding false positive and negative results.