:: wikimiki.org ::
| Aedes |
Aedes
Aedes albopictus
Aedes aegypti
This page is about the genus of mosquito, for the Roman building see aedes (Roman)
Aedes is a genus of mosquito found in tropical and subtropical zones. The name comes from the Greek aēdēs, meaning unpleasant, so called because of the diseases this mosquito transmits, which include dengue and yellow fever. The genus was named by Johann Wilhelm Meigen in 1818.There are presently some controversial moves afoot to abolish Aedes as a generic name and to replace it with Stegomyia.
Currently, the Aedes aegypti genome is being sequenced by TIGR, The Institute for Genomic Research, and is expected to be finished around the end of the year.
Category:Flies
ms:Aedes
Aedes albopictus
Aedes albopictus (Family Culicidae), the Asian Tiger Mosquito or Forest Day Mosquito, is characterized by its black and white striped legs and small, black and white body. It was native to Southeast Asia, and occupied a habitat that spread from Madagascar eastward to New Guinea, and north to the latitude of Korea.
The typical member of the Aedes albopictus has a length of about 5 mm. As with other members of the mosquito family, the female is equiped with an elongated proboscis that she uses to collect blood to feed her eggs. By contrast the male member of the species primarily feeds on nectar. The female reproduces by laying her eggs in water, which is typically a stagnant pool. However any open container containing water will suffice.
Invasive species
This species is able to survive in a wide range of habitats and conditions. It is generally more aggressive than indigenous mosquitoes, and is outcompeting them. The asian tiger mosquito has a rapid bite that allows to escape most attempts by people to swat it.
Other mosquitoes in North America, such as Ochlerotatus canadensis, have a similar leg pattern. Asian Tiger Mosquitoes were first found in North America in a shipment of used tires at the port of Houston in 1985. Since then they have spread across southern USA, and as far up the East Coast as southern New Jersey. This species is an introduced species in Hawaii as well, but has been there since before 1896.
This mosquito has become a significant pest in many communities because it closely associates with humans (rather than living in wetlands), and typically flies and feeds in the daytime rather than at night or at dusk and dawn. It is a container and puddle breeder, needing only a few ounces of water to breed. It has a short flight range (less than 200 m), so breeding sites are likely to be close by where you find this mosquito (Nishida & Tenorio, 1993).
It has not been implicated as a carrier of West Nile virus, but can carry Eastern Equine Encephalitis. It is also a known vector of dengue fever in Central America, South America, and the Pacific.
Controlling Asian Tiger Mosquitoes
A lot of futile and risky spraying has been done in the last few years because of the West Nile virus scare. This mosquito is active in the day time and so is identified if people are being bitten in the day time. Most mosquito spraying is done at night and will have little effect on Asian Tiger mosquitoes. (Daytime spraying is usually a violation of label directions because of foraging bees on blossoms in the application area.)
bee
It is however, simple to find and deal with the breeding spots, which are never far from where people are being bitten, since this is a weak flyer. Locate puddles that last more than 3 days, sagging or plugged roof gutters, old tires holding water, litter, bird baths, kiddie pools, and any other possible containers or pools of standing water. Flowing water will not be a breeding spot and water that contains minnows is not usually a problem, because the fish eat the mosquito larvae. Dragonflies are also an excellent method of imposing control. Dragonfly larvae eat mosquito larvae in the water, and adults will snatch adult mosquitoes as they fly. Insecticide application that also kills dragonflies may actually cause only a brief suppression of mosquitoes, followed by a long term increase in populations.
Whenever possible, all sources of standing water, even if only a quarter cup, should be dumped every three days. Litter, especially containers in ditches, can hold water after the ditch dries up, and all litter should be cleaned up. Bird baths, wading pools, and any other container that can hold rainwater should be emptied. Rain barrels used for garden irrigation, and many other containers that cannot be dumped can be treated with a spoonful of vegetable oil, which will suffocate mosquito larvae as they try to breathe at the surface.
Any standing water in pools, catchment basins, etc, that cannot be drained, dumped, or treated with a small quantity of vegetable oil, can be periodically treated with Bacillus thuringiensis israelensis. This is a disease organism that only affects the pest insects. It is readily available at farm, garden and pool suppliers.
References
- Nishida, G.M. and J.M. Tenorio. 1993. What Bit Me? Identifying Hawai'i's Stinging and Biting Insects and Their Kin. University of Hawaii Press, Honolulu. 72 pp.
- [http://www.iberianature.com/material/tigermosquito.htm Tiger mosquitoes in Spain] News tracking the recent spread of the tiger mosquito to Spain
Category:Flies
Category:Invasive species
Aedes aegypti
Stegomyia aegypti (St. aegypti) is a mosquito that can host the dengue and yellow fever viruses (and other diseases as well). In 2005 the subgenus Stegomyia was elevated to generic level, changing the name for this mosquito to Stegomyia aegypti from Aedes (stegomyia) aegypti or Aedes aegypti. Interestingly, Aedes aegypti used to be called Stegomyia in the past. Stegomyia aegypti is considered the primary vector for both dengue and yellow fever. The mosquito can be recognized by white markings, although other mosquitoes may have only slightly different patterns. The mosquito is most frequently found in the tropics, but has some presence in the southern eastern part of the US (such as the lower half of florida) although it seems to have been competitively displaced by the introduction of Aedes albopictus.
The CDC traveler's page on preventing dengue fever suggests using mosquito repellants that contain N,N-diethylmetatoluamide (DEET). Presumably this has some effectiveness in repelling Aedes aegypti. The CDC traveler's page also explains the following:
1) Although it may feed at any time, the mosquito's periods of peak biting activity are few hours after dawn and in the late afternoon until a few hours after dark.
2) The mosquito's preferred breeding areas are in areas of stagnant water, such as flower vases, uncovered barrels, buckets, discarded tires, but the most dangerous areas are wet shower floors and toilet bowls, as they breed right in the residence.
External links
- [http://gvcocks.homeip.net/Diptera/Culicidae/aedes%20egypti.htm A page that has an image of Stegomyia aegypti]
- [http://medent.usyd.edu.au/photos/aedes%20aegypti.htm Aedes aegypti page from University of Sydney, Australia]
- [http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/art98/aedrol.html Aedes aegypti and Dengue fever]
- [http://www.cdc.gov/ncidod/dvbid/dengue/ United States CDC page on dengue fever containing information on prevalence of Aedes aegypti worldwide and past efforts to eradicate it]
Genus
In biology, a genus (plural genera) is a grouping in the classification of living organisms having one or more related and morphologically similar species. In the common binomial nomenclature, the name of an organism is composed of two parts: its genus (always capitalized) and a species modifier. An example is Homo sapiens, the name for the human species which belongs to the genus Homo. See scientific classification for more details of this system.
The type genus of a taxon is usually the first genus to be named and described. Families, and in plants all taxa up to division, are named after the type genus. The genus and these higher taxa are typified by a specimen that shows the characteristics of the genus. The specimen used to describe this species is preserved as the holotype and designated as a generitype in a zoological museum or a herbarium to be available for further study.
A generic name in one kingdom is allowed to bear the same name as a genus or other taxon name in another kingdom (though this is discouraged by the International Code of Zoological Nomenclature). For instance, Anura is a genus of plants in the family Asteraceae and the order of frogs; Aotus is the genus of golden peas and night monkeys; Oenanthe is the genus of wheatears and water dropworts, and Prunella is the genus of accentors and self-heal. It is, however, not allowed for two genera within the same kingdom to have the same name. This explains why the platypus genus is Ornithorhynchus — although the name Platypus was chosen by George Shaw in 1799, that name had already been given to the ambrosia beetle by Johann Friedrich Wilhelm Herbst in 1793. Since beetles and platypuses are both member of the kingdom Animalia, the name Platypus could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800.
See also
- Linnaean taxonomy
- Cladistics
rank17
rank17
rank17
als:Gattung (Biologie)
ms:Genus
th:สกุล (ชีววิทยา)
Mosquito
See text.
The mosquito is a member of the family Culicidae; these insects have a pair of scaled wings, a pair of halteres, a slender body, and long legs. The females of most mosquito species suck blood from other animals. Size varies but is rarely greater than 15 mm (0.6 inch). Mosquitoes weigh only about 2 to 2.5 mg (0.03 to 0.04 grain). They can fly at about 1.5 to 2.5 km/h (0.9 to 1.6 mph) and most species are nocturnal.
Mosquitoes are believed to have evolved around 170 million years ago during the Jurassic era (206–135 million years ago) with the earliest known fossils from the Cretaceous era (144–65 million years ago). They evolved in the land mass that is now South America, spreading initially to the northern continent Laurasia and re-entering the tropics from the north. Ancestral mosquitoes were about three times the size of the extant species and they are a sister group to the Chaoboridae (biting midges).
The family Culicidae belongs to the order Diptera and contains about 3500 species in three subfamilies: Anophelinae (3 genera), the Culicinae (9 genera and >80% of all the species) and the Toxorhynchitinae (1 genus). The genera include Anopheles, Culex, Psorophora, Ochlerotatus, Aedes, Sabethes, Wyeomyia, Culiseta, and Haemagoggus. Within the family Anophelinae six subgenera are recognized: Stethomyia, Lophopodomyia, Kerteszia, Nyssorhynchus (all South American), Cellia (Old World only) and Anopheles (worldwide).
Mosquitos are principally nectar feeders with only the females requiring a meal of blood. In contrast to this rule the Toxorhynchites never drinks blood. This family includes the largest of the extant mosquitoes (colloquially referred to as "mosquito eaters") and their larvae are predatory on the larvae of other mosquitoes. Attempts have been made in the past to use these as mosquito control agents but with variable success.
Mosquito is a Spanish word meaning "little fly", with its use dates back to about 1583. Before then, they were called "biting flies" in English, but the term "mosquito" was adopted to prevent confusion with the house fly. The word derives from Sanskrit maksh (fly) via the Latin word musca (fly) and the Italian moschetta or Spanish mosquito (little fly). The French word is moustique.
The female mosquito (in almost all species) sucks the blood of mammals, including humans — commonly referred to (incorrectly) as a "bite." Mosquito bites often swell up hours after happening, causing a red ringed white bump about a centimeter in diameter. This bump can itch for days and over-scratching the bite can cause it to bleed. Mosquito bites can transmit diseases, such as malaria and West Nile Virus, so authorities in many areas take measures to reduce mosquito populations through pesticides or more organic means. An easy way to reduce mosquito populations in a residential area is the removal of standing water (where mosquitoes breed), and the use of repellents, such as DEET.
Natural history
DEET
In most female mosquitoes, the mouth parts form a long proboscis for piercing the skin of mammals (or in some cases birds or even reptiles and amphibians) to suck their blood. As opposed to a syringe's typically smooth needle, the mosquito proboscis is highly serrated, which leaves a minimal number of points of contact with the skin being pierced — this reduces nerve stimulation to the point where the "bite" is not felt at all, which is generally the case (see the Mosquitoes and health section below for an explanation on the swelling.) The females require protein for egg development, and since the normal mosquito diet consists of nectar and fruit juice, which has no protein, most must drink blood to get the necessary protein. Males differ from females, with mouth parts not suitable for blood sucking.
Mosquitoes and health
The mosquito undergoes complete metamorphosis, going through four distinct stages in its life cycle: egg, larva, pupa, and adult — a process that was first described by the Greek philosopher Aristotle. The length of the first three stages is dependent on the species and temperature. Culex tarsalis may complete its life cycle in 14 days at 20 °C (68 °F) and only ten days at 25 °C (77 °F). Some species have a life cycle of as little as four days or up to one month. The larvae are the "wrigglers" or "wigglers" found in puddles or water-filled containers. These breathe atmospheric oxygen through a siphon at the tail end. The pupae are nearly as active as the larvae, but breathe through thoracic "horns" attached to the thoracic spiracles. Most larvae feed on microorganisms, but a few are predatory on other mosquito larvae. Some mosquito larvae, such as those of Wyeomyia live in unusual situations. These mosquito wigglers live either in the water collected in epiphytic bromeliads or inside water stored in carnivorous pitcher plants. Larvae of the genus Deinocerites live in crab holes along the edge of the ocean.
Most mosquito species outside of the tropics overwinter as eggs, but a significant minority overwinter as larvae or adults. Mosquitoes of the genus Culex (a vector for St. Louis encephalitis) overwinter as mated adult females.
St. Louis encephalitis
The females of blood sucking species locate their victims primarily through scent. They are extremely sensitive to the carbon dioxide in exhaled breath, as well as several substances found in sweat. Some people seem to attract mosquitoes more than others. Empirical studies of mosquito bites suggest that the risk of being bitten follows an approximately negative binomial distribution. Being male, being overweight, and having type 'O' blood may increase the risk of being bitten. Mosquitoes can detect heat, so they can find warm-blooded mammals and birds very easily once they get close enough.
Mosquitoes and health
In the United States, mosquito bites are mostly a nuisance. However, worldwide, mosquitoes are a major public health problem; they are estimated to transmit disease to more than 700 million annually, and will be responsible for the deaths of about one in 17 people currently alive. [http://www.slu.edu/colleges/sph/csbei/emerginginfections/wnv/key_ref/acp_asim_1.pdf]
Some mosquitoes are capable of transmitting protozoan diseases such as malaria (see Plasmodium falciparum), filarial diseases like filariasis, and viral diseases such as yellow fever, dengue, epidemic polyarthritis, encephalitis, and West Nile virus.
West Nile virus was accidentally introduced into the United States in 1999 and by 2003 had spread to almost every state. Through the transmission of such diseases, it can be argued that mosquitoes have caused more human deaths than any other animal.
When a mosquito first bites a human, she injects saliva and anti-coagulants. When one is first bitten there is no reaction, but after several bites the body's immune system develops antibodies and an itchy red mark appears about a day after the bite. This is the usual reaction in young children.
After many more bites, the sensitivity of the human immune system increases, and an itchy red hive appears in minutes where the immune response has broken capillary blood vessels and fluid has collected under the skin. This type of reaction is common in older children and adults.
Some adults could possibly become desensitized to mosquitoes, and not have any reaction to their bites, but others can become hyper-sensitive with bites causing large painful red welts.
Mosquitoes are also very irritating as sometimes they tend to fly around the ears of humans, their wingbeats coming within audible range of the human ear. This is especially more pronounced during the monsoon season in tropical climates, when the incidence of mosquitoes increases manyfold. The buzzing noise wakes up people who would otherwise have not been disturbed by the mosquito bite alone. This has prompted many to stuff their ears with cotton to shut out the buzzing of the mosquitoes.
Mosquito control and integrated mosquito management
There are two kinds of mosquito control: large, organized programs to reduce mosquito populations over a wide area, and actions and invidual can take to control mosquitoes with respect to themselves and their own property.
Organized mosquito control programs today draw on the principles of integrated pest management. An integrated mosquito control program typically includes the following measures, all guided by surveillance of mosquito populations and knowledge of the mosquito life cycle: [http://vector.ifas.ufl.edu/chap03.pdf]
- source reduction - the removal of mosquito breeding habitats
- habitat modification - manipulating habitats to reduce breeding
- biocontrol - introducing natural predators of mosquitoes
- larvicide - using pesticides to reduce larval populations
- adulticide - using pesticides to reduce adult populations
Since many mosquitoes breed in standing water, source reduction can be as simple as overturning an old tin can, or can be as complex as permanently draining marshes. Much source reduction is a matter of education. For example, homeowners can eliminate mosquito breeding grounds by removing unused plastic pools, old tires, or buckets; by clearing clogged gutters and repairing leaks around faucets; by regularly changing water in bird baths; and by filling or draining puddles, swampy areas, and tree stumps. Eliminating such mosquito breeding areas can be an extremely effective and permanent way to reduce mosquito populations without resorting to insecticides.
Habitat modification, such as ditching or diking marshes or manipulating daily water flows can be effective at reducing mosquito populations by disrupting the mosquito life cycle, but experience has shown that such large-scale programs can be harmful to the ecosystem if not undertaken carefully. One example of a successful approach to habitat modification, open marsh water management, involves the use of shallow ditches to connect the shallow waters where mosquitoes breed to deeper waters where natural predators live. Simply giving the predators access to the mosquito larvae can result in long-term mosquito control.
Biocontrol is the direct introduction of predators to target mosquitoes. Effective biocontrol agents include predatory fish that feed on mosquito larvae such as Gambusia affinis and other minnows and killifish. Some other biocontrol agents that have had lesser degrees of success include the predator mosquito Toxorhynchites and predator crustaceans, nematodes, and fungi. Some public agencies also employ other predators such as birds, bats, dragonflies, and frogs, but evidence of effectiveness of these agents is only anecdotal. In particular, there is no documented study that establishes that bats or purple martins consume enough mosquitoes to significantly control mosquito populations.
Also used as biological control agent are the dead spores of varieties of the natural soil bacteria Bacillus thuringiensis, especially Bt israelensis (BTI). BTI is used to interfere in the digestion systems of larvae. It can be dispersed by hand or dropped by helicopter in large areas. BTI is no longer effective after the larvae turn into pupae, because they stop eating.
At this point larviciding oils, such as Golden Bear, can be used which increase the water tension until the pupae and larvae cannot break the surface to obtain air and therefore drown. A chemical commonly used in the United States is methoprene, considered slightly toxic to larger animals, which mimics and interferes with natural growth hormones in mosquito larvae, preventing development. Methoprene is frequently distributed in time-release briquette form in breeding areas.
Adulticide, the ground or arial application of chemical pesticides, is less effective than the other methods of mosquito control and is generally considered a method of last resort. Nevertheless, careful application of adulticide is considered a critical part of integrated mosquito management. For example, ultra low volume (ULV) spraying of Malathion has been used in metropolitan areas like New York City to decrease the mosquito population and prevent the spread of West Nile Virus.
The most effective solutions for malaria control efforts in the third world are: mosquito nets (klamboe), insecticide-laced mosquito nets, and DDT. [http://www.cdc.gov/malaria/control_prevention/vector_control.htm] Plain mosquito nets are cheap, they are completely effective in protecting humans within the net, they do not adversely affect the health of natural predators such as dragonflies, and do not require sophisticated public health capacity on the part of the government.
The role of DDT in combating mosquitoes has been the subject of considerable controversy. While some argue that DDT deeply damages biodiversity, others argue that DDT is the most effective weapon in combating mosquitoes and hence malaria. While some of this disagreement is based on differences in the extent to which disease control is valued as opposed to the value of biodiversity, there is also genuine disagreement amongst experts about the costs and benefits of using DDT. Moreover, DDT-resistant mosquitoes have started to increase in numbers, especially in tropics due to mutations, reducing the effectiveness of this chemical.
Mosquito repellants and personal mosquito control
Mosquito repellants generally contain one of the following active ingredients: DEET, Catnip oil extract, nepetalactone, citronella, or eucalyptus oil extract. Often the best "repellant" is a fan or gentle breeze as mosquitoes do not like moving air.
Other popular methods of household mosquito control include use of small electrical mats, mosquito repellent vapour, and mosquito coil, all containing a form of the chemical allethrin. Mosquito repellant candles containing Citronella oil is another method to keep mosquitoes at bay. Some more lesser known methods use the cultivation of plants like wormwood or sagewort, lemon balm, lemon grass, lemon thyme and the mosquito plant (Pelargonium) which act against mosquitoes. However scientists have determined that these plants are effective only when the leaves are crushed and used.
There are several widespread theories about mosquito control such as the assertion that Vitamin B, garlic, ultrasonic devices, incense, bats, purple martins and bug zappers can be used to repel or control moquitoes [http://dermnetnz.org/arthropods/bites.html]. Whether these methods are effective at deterring mosquitos or significantly reducing mosquito populations remains disputed.[http://www.vnh.org/NHB/HW9421Mosquito2.html] Moreover, some manufacturers of "mosquito repelling" ultrasonic devices have been found to be fraudulent [http://www.ftc.gov/opa/2002/08/lentek.htm].
Although bats can be prodigious consumers of insects, many of which are pests, less than 1% of a bat's diet will consist of mosquitoes; bats mostly feed on larger insects such as beetles. Bats are known carriers of rabies, so care must be taken if attempting to use bats to control insects. Similarly, bug zappers kill a wide range of flying insects including many beneficial insects as well as mosquitoes; bug zappers are not effective at controlling mosquito populations.
Some newer mosquito traps emit a plume of carbon dioxide together with other mosquito attractants such as chemical scents, warmth, water vapor and sounds. By mimicking a mammal, these factors draw female mosquitoes toward the trap, where they are typically sucked into a net or holder where they collect. According to the American Mosquito Control Association [http://www.mosquito.org/trapqueries.php], "these devices will, indeed, trap and kill measurable numbers of mosquitoes," but their effectiveness in any particular case will depend on a number of factors such as the size and species of the mosquito population and the type and location of the breeding habitat. The relative effectiveness of these newer mosquito traps is still being studied.
External links
- [http://www.mosquito.org/mosquito-information/index.aspx American Mosquito Control Association - Mosquito Information]
- [http://www.slu.edu/colleges/sph/csbei/emerginginfections/wnv/key_ref/acp_asim_1.pdf Mosquitoes and mosquito repellents: a clinician’s guide]
- [http://vector.ifas.ufl.edu/chapter_03.htm University of Florida Public Health Pesticide Applicator Training Manual - Chapter on Mosquitoes]
- [http://klab.agsci.colostate.edu/ Mosquito Genomics WWW Server]
- [http://www.microscopy-uk.org.uk/mag/artsep03/drmosq.html Mosquitoes - Micscape September 2003]
- [http://www.mosquito-pictures.com Mosquito pictures] - Shares facts and pictures regarding mosquitoes and their behavior, life cycle, and feeding habits.
- [http://www.mosquito-kill-net.com/mosquito-pictures.html Close up mosquito pictures] - Close up shots of mosquitoes before and after feeding and while mating.
- [http://hypertextbook.com/facts/2000/DianaLeung.shtml Frequency of Mosquito Wings]
- [http://www.cieh-npap.org.uk/documents/Human_biting_mosquito_species_of_the_British_Isles.pdf Mosquito Species of the British Isles] (PDF file)
- [http://www.blackwellpublishing.com/ridley/tutorials/The_theory_of_natural_selection__part_1_13.asp The evolution of DDT resistant mosquitoes]
- [http://www.cdc.gov/ncidod/dvbid/ CDC Division of Vector-Bourne Infectious Diseases] - Information on West Nile virus as well as other mosquito- and tick- bourne diseases.
- [http://dermnetnz.org/arthropods/bites.html New Zealand Dermatological Society Incorporated] - Insect bites and stings and how to prevent them.
Category:Parasitology
Category:Flies
Category:Insects
ko:모기
ms:Nyamuk
ja:カ
Dengue
:This article is about the tropical disease. For the article about the California-based psychadelic rock band, see Dengue Fever (band).
Dengue and dengue hemorrhagic fever (DHF) are acute febrile diseases, found in the tropics, with a geographical spread similar to malaria. Caused by one of four closely related virus serotypes of the genus Flavivirus, family Flaviviridae, each serotype is sufficiently different that there is no cross-protection and epidemics caused by multiple serotypes (hyperendemicity) can occur. Dengue is transmitted to humans by the mosquito Aedes aegypti (rarely Aedes albopictus).
Signs and symptoms
The disease is manifested by a sudden onset of fever, with severe headache, joint and muscular pains (myalgias and arthralgias—severe pain gives it the name break-bone fever) and rashes; the dengue rash is characteristically bright red petechia and usually appears first on the lower limbs and the chest - in some patients, it spreads to cover most of the body. There may also be gastritis with some combination of associated abdominal pain, nausea, vomiting or diarrhoea.
Some cases develop much milder symptoms, which can, when no rash is present, be misdiagnosed as a flu or other viral infection. Thus, travelers from tropical areas may inadvertently pass on dengue in their home countries, having not being properly diagnosed at the height of their illness. Patients with dengue can only pass on the infection through mosquitoes or blood products while they are still febrile.
The classic dengue fever lasts about six to seven days, with a smaller peak of fever at the trailing end of the fever (the so-called "biphasic pattern"). Clinically, the platelet count will drop until the patient's temperature is normal.
Cases of DHF also shows higher fever, haemorrhagic phenomena, thrombocytopenia and haemoconcentration. A small proportion of cases leads to dengue shock syndrome (DSS) which has a high mortality rate.
Diagnosis
The diagnosis of dengue is usually made clinically. The classic picture is high fever with no localising source of infection, a petechial rash with thrombocytopenia and relative leukopenia.
Serology and PCR (polymerase chain reaction) studies are available to confirm the diagnosis of dengue if clinically indicated.
Treatment
The mainstay of treatment is supportive therapy. The patient is encouraged to keep up oral intake, especially of oral fluids. If the patient is unable to maintain oral intake, supplementation with intravenous fluids may be necessary to prevent dehydration and significant hemoconcentration. A platelet transfusion is indicated if the platelet level drops significantly.
Epidemiology
The first epidemics occurred almost simultaneously, in Asia, Africa, and North America in the 1780s. The disease was identified and named in 1779. A global pandemic began in Southeast Asia in the 1950s and by 1975 DHF had become a leading cause of death among children in many countries in that region. Epidemic dengue has become more common since the 1980s - by the late 1990s, dengue was the most important mosquito-borne viral disease affecting humans after malaria, there being around 40 million cases of dengue fever and several hundred thousand cases of dengue hemorrhagic fever each year. In February 2002 there was a serious outbreak in Rio De Janeiro, affecting around one million people but only killing sixteen.
Significant outbreaks of dengue fever tend to occur every five or six years. There tend to remain large numbers of susceptible people in the population despite previous outbreaks because there are four different strains of the dengue virus and because of new susceptible individuals entering the target population, either through childbirth or immigration.
There is significant evidence, originally suggested by S.B. Halstead in the 1970s, that dengue hemorrhagic fever is more likely to occur in patients who have secondary infections by serotypes different from the primary infection - in a process known as antibody-dependent enhancement (ADE). Therefore, people that have passed a primary infection are usually advised to minimise the risk of a second one.
In Singapore, there are about 4000-5000 reported cases of dengue fever or dengue haemorrhagic fever every year. In the year 2003, there were 6 deaths from dengue shock syndrome. It is believed that the reported cases of dengue are an underrepresentation of all the cases of dengue as it would ignore subclinical cases and cases where the patient did not present for medical treatment. With proper medical treatment, the mortality rate for dengue can therefore be brought down to less than 1 in 1000.
Prevention
There is no commercially ready vaccine for the dengue flavivirus.
Primary prevention of dengue mainly resides in eliminating or reducing the mosquito vector for dengue. Initiatives to eradicate pools of standing water (such as in flowerpots) have proven useful in controlling mosquito borne diseases. Promising new techniques have been recently reported from Oxford University on rendering the Aedes mosquito pest sterile.
Personal prevention consists of the use of mosquito nets and repellents.
Potential antiviral approaches
In cell culture experiments Morpholino antisense oligos have shown specific activity against Dengue virus [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15795296] .
Recent outbreaks
Recent dengue outbreaks in South East Asia:
- Philippines ([http://news.inq7.net/breaking/index.php?index=2&story_id=53192 January - October 2005]) 21,537 cases with 280 dead.
- Thailand (May 2005) 7200 infected. At least 12 dead.
- Indonesia (2004) 80,000 infected with 800 deaths.
- Malaysia (January 2005), 33,203 cases.
- Singapore (2005), At least 13 deaths, (2004), 9460 cases, (2003), 4788 cases.
As of September 2005, Singapore reported a significant rise in the number of dengue cases - about 9000 in the year to date so far, about double the rate for the same period in 2004. It is even possible to have more than 500 cases per week. The large increase in dengue cases has caused hospitals to cancel some elective surgery due to the need to allocate more beds for dengue patients.
September 2005
References
- Theiler, Max and Downs, W. G. 1973. The Arthropod-Borne Viruses of Vertebrates: An Account of The Rockefeller Foundation Virus Program 1951-1970. Yale University Press.
- Downs, Wilbur H., et al. 1965. Virus diseases in the West Indies. Special edition of the Caribbean Medical Journal, Vol. XXVI, Nos. 1-4, 1965
External link
- [http://edition.cnn.com/2004/WORLD/asiapcf/02/20/indon.dengue/ CNN report on dengue fever].
Category:Infectious diseasesCategory:Flaviviruses
- [http://www.cdc.gov/ncidod/dvbid/dengue/index.htm CDC site on Dengue Fever].
Category:Infectious diseasesCategory:Flaviviruses
See also:
- Tropical disease
zh-min-nan:Thian-káu-jia̍t
ms:Demam Denggi
ja:デング熱
Johann Wilhelm MeigenJohann Wilhelm Meigen (3 May 1764 - 11 July 1845) was a German entomologist famous for his pioneering work on Diptera.
Life
Early Years
Meigen was born on 3 May 1764 in Solingen, Germany, the fifth of eight children of Johann Clemens Meigen and Sibylla Margaretha Bick. His parents, though not poor, were not wealthy either. The ran a small shop in Solingen. His paternal grandparents however owned an estate and hamlet with twenty houses. Adding to the rental income, Meigen’s grandfather was a farmer and a guild mastercutler in Solingen.
Two years after Meigen was born his grandparents died and his parents moved to the family estate. This was already heavily indebted by the Seven Years War, then bad crops and rash speculations forced sale and the family moved back to Solingen.
Meigen attended the town school but only for a short time. Fortunately he had learned to read and write on his grandfather’s estate and he read widely at home as well as taking an interest in natural history. A lodger in the household, a state surveyor named Stamm gave Meigen instruction in mathematics. Another family friend a Reformed Church organist and teacher called Berger, gave him lessons from his 10th year on in piano, orthography, and calligraphy, Later on, in 1776, he also taught him French.
Meigen became Berger's assistant, going to Mülheim, with him. There he saw for the first time a systematic collection of butterflies, and here he also learnt how to collect and prepare insects.
In the Autumn of 1779 he returned to Solingen to help his parents, at first by giving private lessons in French, but in the following year he started a French school that lasted until early in 1784. During his few free hours in this period he studied history from Charles Rollin's 15 volume Roman History and that author's 4 volume Ancient History (both in French). The
only entomological work in his possession at this time was Moder's (or Kleemann's) Caterpillar Calendar.
Later in 1784 he was recommended to Pelzer,a tradesman in Aachen, for the position of resident tutor.On taking up the post, he was treated as a family member.Pelzer had a cousin in Aachen by the name of Mathias Baumhauer,a wool merchant's son, who was a very able entomologist. Baumhauer had a butterfly collection including about 1200 species as well as numbers of insects of all other orders.
Early entomology
Meigen’s first attempts to identify his collection which was mainly of Diptera were made with a two volume work by Philipp Ludwig Statius Muller a German translation of Linnaeus's Natursystem published in Holland by Houttyn. He soon made his first discovery. The Linnean genera were too inclusive and a better classification could be arrived at using wing venation. This conclusion had already occurred to both Moses Harris in England and Louis Jurine in Geneva but at the time Meigen was unaware of this. Sensing an important step forward he secured the works of Fabricius and from that time concentrated on Diptera.
He soon found that wing venation alone was not enough to classify the Dipera correctly and he began to make drawings of the antennae viewed under a 20-power wooden-framed microscope purchased at the fair in Aachen, This, a lens of about 6-power, and his own very sharp eyesight and visual memory led him to the next important conclusion, that the Diptera could only be classified using character combinations; what is now known as an eclectic system..
Return to Solingen
In 1786 the Solingen organist, a younger brother of his former teacher Berger died in Solingen. That position, with a French school connected with it,was offered to Meigen and he went back to Solingen.
There he became closely accquainted with a man called Weniger, who shared his interests in botany and entomology.His enthusiasm for entomology and botany became broader and he decided to extend his studies to world species. Weniger felt likewise and they contacted a Herr Gerning in Frankfurt. Gerning wrote to his son in Holland,who bought insect specimens for him. A Swiss, Count von Meuron, who was in the Dutch service and whose brother was governor of Trincomalee on Ceylon heard of their wishes and obtained for them the offer of positions as surgeons on an East Indiaman, with an additional stipend.This plan was given up when Meigen’s mother opposed it.
To Burtscheid
In 1792 Meigen took instruction in drawing. Then he was offered a teaching position in Burtscheid near Aachen. However, he could not leave Solingen because the it was occupied by the French army during the Battle of Jemappes . Only when the French withdrew after the Battle of Neerwinden was he able to leave for Burtscheid and Aachen, where he then taught as well as collecting assiduously.
In 1796, Meigen took a job teaching French in Stolberg, 2 hours from Aachen. Here he remained without further change of residence until his death. In Stolberg outside of school hours he taught drawing,geography, history and piano.He also met a brass-worker named J. A. Peltzer, who was a mathematician and owned a 60-power Tiedemann achromatic telescope. Soon Meigen was teaching astronomy as well.
In 1801 Meigen met the French naturalist Count Lacépède who had come to Stolberg to visit the brass works. They talked about natural history and Meigen showed Count Lacépède his drawings of Diptera. The following day Meigen was asked to visit Count Lacépède who asked him to join Capt. Baudin's voyage around the world as a botanist. Meigen declined.
In 1802 Johann Karl Wilhelm Illiger who must have heard of Miegen from Count Lacépède and was at the baths in Aachen with Johann Centurius Hoffmannsegg invited him to join them. Meigen took his drawings along, and made arrangements with Illiger and Hoffmannsegg for future work. Illiger had captured a new and unknown Dipteron and showed a pen drawing of it to Meigen, asking him how it should be classified. Meigen described it as Eoxocera Hoffmannseggi. Illiger also agreed to proofread Meigen's first work on Diptera which was then published in 1804 by Reichard in Braunschweig.
Controversy
In 1804 the only classification of Diptera was that of Fabricius . Despite Meigen’s more advanced, and more natural classification, Meigen's Die Fliegen found little favour with most entomologists, who were adherents of Fabricius, but that did not deflect Meigen.
In the same year Fabricius visited Paris and saw Meigen’s work. On returning home, he wrote Meigen and arranged to meet him in Aachen. A few days later Fabricius came to Stolberg Here he was shown all of Meigen's new genera in order that he might use them in the projected new edition of Systema Antliatorum. Fabricius criticized Meigen for his eclectic method, asserting that a classification should be based upon one part of the body, (mainly mouthparts) not on several different parts. Meigen pointed out that Fabricius himself did not consistently follow his own precepts but even so Fabricius refused to use the eclectic method.
Marriage
In 1801 Meigen married Anna, the sister of the Reverend Mänsse, a preacher at Hückelhoven near Linnich. Anna was clearly devoted to Meigen which was as well since hard times were ahead. Until 1808 the number of students of French steadily declined, resulting of course in a considerable reduction in Meigen's income.In this crisis, a merchant in Stolberg, one Adolf Pelzer, obtained for him the secretaryship for the Stolberg commercial committee, including keeping minutes of meetings and carrying on correspondence in both German and French. Then, in another reversal, he was replaced by a voluntary secretariat.
Coal Fossils
In 1812 the French government provided Meigen with the job of finishing drawings of coal fossils. At this time his work day began usually at about 4 in the morning and lasted until late in the evening for 314 days of each year. All free time was spent with the study of entomology mostly Diptera,but also otherorders. He also studied history and mathematics.At this time Meigen drew and coloured Many more species for Die Fliegen.
From 1812 to 1814 Meigen drew some maps for the municipality of Stolberg. He also corresponded again with Count von Hoffmannsegg, until the latter sold his collection to the Berlin Museum.
An offer from Wiedemann
In 1815, Meigen received a letter from State Attorney (Justizrat) Christian Rudolph Wilhelm Wiedemann asking if there was any prospect that his work begun in 1804 could be continued. He offered access to the Fabricius collection in the University of Kiel.Then in the summer of 1816 Wiedemann came to Stolberg and stayed 8 days to outline an ambitious project. He had material sent to Meigen from the Vienna Museum, from the Hoffmannsegg collection in Berlin, and from the Peter Simon Pallas collection. Meigen worked constantly and in 1818 the first volume of the new and enlarged edition of Die Fliegen came out, followed by the others until the 7th volume appeared in 1838. For this last volume Meigen had to make the lithographic plates himself to cut expenses. He also prepared 19 lithographic plates for Wiedemann's Aussereuropaische Zweiflugler. The first volumes of Die Fliegen were published by Meigen himself, but the costs were high, in spite of a considerable list of subscriptions. The Schulz bookdealers in Hamm took over the job with a sizeable honorarium.
In 1818, Meigen's longtime friend, the tireless collector, Baumhauer died in Paris. His widow brought his collection to Aachen and got Meigen to determine it. He took on the determination of at least 50,000 specimens from Germany, France, the Pyrenees, the Alps and northern Italy and worked on it for a year and a half.The collection was then sold for 1100 Dutch guilders, part of it going to Leiden and part to Luttich.
These years were very certainly hard. In 1816 and 1817 Because of poor harvests, food prices rose enormously. There were 7 children in his family at this time and his income was extremely low, there being now no demand for a French teacher, the French Empire having collapsed . Eventually, through the fortunate intervention of the inspector of water supply, he got a well paid contract for some map-drawing lasting a couple of years. Astronomy also brought him some map-work.
He was able,however to make a trip to the Siebengebirge chiefly for botany and Meigen made some drawings of plants for Prof. Johann Georg Christian Lehmann a Hamburg botanist.
In 1821, Meigen made the acquaintance of Prof. Gaede of Luttich, whose name he gave to Trypeta gaedii and the tachinid genus Gaedia.
Wiedemann's second visit and a trip to Scandinavia
In 1822 Wiedemann made a second visit to Meigen, proposing that Meigen come to Kiel and revise the Fabrician collection,
and offering to defray expenses.Meigen accepted, leaving for Hamburg on 23 June 1823. He was met in Hamburg
by the entomologist Wilhelm Von Winthem, who invited him to stay at his home.Meigen, found himself in the house in which the great poet and dramatist Klopstock spent the last 30 years of his life and which Von Winthem's sister, Johanna Elisabeth von Winthem, Klopstocks widow, then owned . Here he studied the Winthem collection which contained so much that Meigen had to leave a more careful review of it for his return trip. He went on to Kiel to meet Wiedemann, He also met Heinrich Boie in Kiel. Next Meigen and Wiedemann went to Copenhagen to visit Westermann and work on the Museum collection, postponing the main job on the Fabrician collection. Meigen was permitted to take all of the material away for examination. On the 19th of July, the two of them went to Lund, where both Prof.Carl Fredrik Fallén and Johan Wilhelm Zetterstedt met them. Meigen examined Fallén's and Zetterstedt's collections at length.
On the 23rd of July, Wiedemann and Meigen returned to Copenhagen, where Meigen stayed On the 30th they were back in Kiel, where everything in the collections of Fabricius and Westermann was carefully examined and compared and the unknown species drawn and described.After completing the research in Kiel, both left for Hamburg.There Meigen examined the Winthem collection, but there were so many new species in it that Winthem decided to send it all to Stolberg, where it could be worked on more conveniently. Also in Hamburg, Meigen met the entomologist Sommer from Altona and the botanist Lehmann.
The trip to Denmark and Sweden lasted altogether 12 weeks, the result of which was a series of colored drawings of more than 400 species of insects, together with their descriptions and a large amount of corrections and notes. Studies of his collection of the Diptera in Fabricius ' collection led to a very substantial revision.
Last Years
Soon after 1822 The French school soon closed down completely and Meigen took the unpaid position of organist for his parish but he wrote a choral book, for which the church board paid him well. Meigen continued in this capacity until 1831.
In 1825, Meigen made a translation of François Fénelon ‘s Telemachus, and in the same year he was enabled to attend a meeting of naturalists in Berlin.Meigen's expenses were organised by Nees von Esenbeck, and many to whom he was known through his works on Diptera. He also saw there again Wiedemann. He took advantage of this occasion to examine the collection of the Berlin Museum and those of Ruthé and Bouché
Von Winthem visited Meigen in 1826. Meigen also made a trip in that year to Crefeld and Dusseldorf. The following year, 1824, a Handbook for Butterfly Collectors appeared under his name, and he also started a much larger work on Lepidoptera. This latter appeared in fascicles, each of 10 quarto plates lithographed by Meigen himself. It went as far as
the Euphalaenae, where lack of funds brought it to a close. He coloured the plates in a few copies. The figures, except a very few borrowed from other works, were drawn by Meigen from specimens,many from the collection of an old friend Seeger.
After discontinuance of the work on Lepidoptera and the completion of that on Diptera with its 6th volume, Meigen had Diptera sent to him for determination from many sources. Outstanding among them were contributions from Walt1 and Bronn, These induced him to work up a supplementary volume, which was notable for the division of the genera Tachina, Musca and Anthomyia into a number of genera based upon more critical characters than those used previous French and English workers.
At the same time Meigen worked industriously-on a Flora of Germany, which was not completed until a few years before his death. The last volume of this work, also containing numerous drawings made largely from nature by Meigen himself,
appeared in 1842. It was his last work.
When the French dipterologist Jean Macquart visited him in 1839 to see his collection, Meigen also showed him 2 thick quarto volumes of drawings containing 300 plates of colored and mostly enlarged drawings of all the species that had described. Macquart told Meigen that he would like to buy them, quoting a price of 1800 francs on behalf of the Jardin des Plantes in Paris. He paid an additional 1200 francs for Meigen's collection of Diptera, which also went to Paris.
Meigen then disposed of his library and the remainder of his collection. His books and fruit and plant collection were bought by the Verein für narturliche Wissenschaften und Gewerbe (Society for useful sciences and industry) in Aachen,
All of his insects other than Diptera were bought by Arnold Foerster, along with a few manuscripts including colored drawings of Hymenoptera.
In 1839, the Crown-Prince of Prussia awarded Meigen with a pension of 200 thalers a year.
On the 3rd of May, 1845 Meigen was presented with a doctor's diploma from the University of Bonn.
Meigen died in Stolberg near Aachen (=Aix-la-Chapelle), on 11 July 1845 at the age of 83.
Achievements
Meigen is universally recognized as the "father" of Dipterology. Aside from his beautifully executed drawings Meigen's great achievement was to employ combinations of morphological characters to work out his scientific classification. This was in contrast to his Swedish contemporary Carl Frederick Fallén who had used mouthpart characters alone. Thus he had come to the same conclusion as Pierre André Latreille,Moses Harris and Louis Jurine though independently and an eclectic methodology was firmly established.
Meigen described a vast number of European Diptera (mostly valid) and his work laid the foundations of all later work on this important insect group.
Meigen was the naming authority of the fruit fly, Drosophila melanogaster, which is a model organism in the study of genetics.
Works
- Meigen, J. W., 1804., Klassifikazion und Beschreibung der europäischen zweiflügeligen Insekten Part 1 , in English, Systematic description of the known European two-winged insects. Reichard,Braunschweig [= Brunswick] (5 November)
- Meigen, J. W., 1820, Systematische Beschreibung der bekannten europäischen zweiflügeligenInsektenPart 2 F.W. Forstmann, Aachen.(before December).
This masterwork work has a long and complicated history, with successive versions in French as well as German.
Collections
Most of the the Meigen collection is in the Muséum National d'Histoire Naturelle, Paris. There are other specimens,including types in the Natural History Museum of Vienna .
External links
- [http://de.wikipedia.org/wiki/Johann_Wilhelm_Meigen Wikisite in German]
- [http://wrbu.si.edu/www/MS/06/MS06N02P079.PDF Biography by J. A. Förster]
Meigen
Meigen
Meigen
HMS QuickmatchHMAS Quickmatch (G92/F04) was a Q class destroyer laid down by J. Samuel White and Company Limited of Cowes on the Isle of Wight in England on 6 February 1941, launched on 11 April 1942 by Mrs. Shearman, commissioned into the Royal Navy as HMS Quickmatch on 14 September 1942, transferred to Australia and paid off on 15 May 1950, underwent conversion to a modern anti-submarine frigate at Williamstown Naval Dockyard in Victoria and re-commissioned on 23 September 1955. HMAS Quickmatch paid off to reserve at Williamstown on 26 April 1963 where she served as an accommodation ship, was sold for scrap to the Fujita Salvage Company Limited of Osaka in Japan on 15 February 1972 and departed Melbourne for Japan under tow on 6 July 1972.
Quickmatch
Quickmatch
seo slots kalorie prag hotel aminokwasy
|
|
|
| :: RELATED NEWS :: |
Neptuno
O termo Neptuno (ou Netuno) pode se referir aos seguintes significados:
- Neptuno, o planeta
- Neptuno, deus da mitologia romana
- P-2 Neptuno, um avião bimotor utilizado para reconhecimento aéreo e
|
Dióxido de carbono
O dióxido de carbono, ou anidrido carbónico (como é conhecido no Brasil, e também em Portugal há alguns anos atrás) é um composto químico constituído por dois átomos de oxigénio e um átomo de carbono. A representação química é CO2. O dióxido de carbono foi descoberto pelo escocês Joseph Black em
|
Monóxido de carbono
O monóxido de carbono é um composto constituído por um átomo de carbono e o um átomo de oxigénio.
É altamente tóxico matando por asfixia.
Categoria:Óxidos
ja:一酸化炭素
ko:일산화 탄소
|
Escravatura
A escravatura, também nomeada de escravidão ou escravagismo no Brasil, é a prática social em que um ser humano tem direitos de propriedade sobre outro designado por escravo, que são impostos involuntariamente sobre o escravo. A escravatura foi comum na Antigüidade em todo o mundo, a partir do momento em que o crescimento populacional nu
|
Phantasy Star
Dentre os jogos eletrônicos, Phantasy Star (ファンタシースター) é o mais famoso RPG para os consoles da SEGA, e tem muitas versões, incluse uma online. Ao contrário da maioria dos RPGs deste tipo, ele tem uma ambientação futurista/fantasia, onde você combate monstros usando armas (como espadas e pistolas) e magias.
Enredo
A primeira versão foi para o Sega Master S
|
História da Jamaica
O nome do país deriva do nome Xamayca, que significa "terra de madeira e água", que lhe foi dado pelo povo Arawak proveniente da América do Sul que se fixou na ilha pela primeira vez por volta do ano 1000.
A Jamaica foi reclamada pela Espanha depois de Cristóvão Colombo a ter descoberto em 1494. Colombo usou a ilha como propriedade privada da sua família. Os
|
Escravos
A escravatura, também nomeada de escravidão ou escravagismo no Brasil, é a prática social em que um ser humano tem direitos de propriedade sobre outro designado por escravo, que são impostos involuntariamente sobre o escravo. A escravatura foi comum na Antigüidade em todo o mundo, a partir do momento em que o crescimento populacional nu
|
Demos
Deimos é a menor e mais afastada das duas luas de Marte. É, também, a menor lua reconhecida do Sistema solar.
Seu nome vem da mitologia grega. Deimos é um dos filhos de Ares (Marte) e Afrodite (Vénus); "deimos" é palavra grega para pânico ou terror.
A lua foi descoberta a 10 de Agosto de 1877 por Asaph Hall e fotografado pela Viking 1 em 1977. Deimos tem um formato bastante irregular e acredita-se tratar de um
|
Líquen
Os líquenes são seres vivos muito simples que se desenvolvem como lâminas ou placas de várias cores na superfície de árvores ou de pedras, expostas à humidade e ao sol. São geralmente estudados pelos botânicos, apesar de não serem verdadeiras plantas. Os líquenes são uma simbiose – um organismo for
|
Meson
Mesão (ou méson) é uma partícula subatômica (um hadrão) composta por um quark e por um antiquark de carga de cor oposta. Frequentemente, um par de quark e antiquark não ocorre isoladamente, mas, em vez disso, mistura-se com outros de
|
|
