Dengue

History

It is in 1779 that it was described for the first time.

It was at the origin of important epidemic S in Australia (1897), with the Seychelles (1926), with Tunis (1927), with Athens (1928) and with Taiwan (1931).

Epidemiology

Whereas it was present only in Southeast Asia, it has been for a few years in full progression in the remainder of the Asia, in Africa and especially in South America (where the number of cases was multiplied by 60 between 1989 and 1993). The reasons are multiple:

demographic growth important;
creation of Shantytown S with the accesses of the cities;
natural disasters;
impoverishment;
deceleration of the eradication campaigns of the mosquito.

The the World Health Organization (WHO) estimates that each year, between 50 and 100 million people is infected in the world. Between 200 000 and 500 000 people suffer from the hemorrhagic form , which kills 20 000 people per annum.

It is the most widespread arbovirose (40% of the world population are exposed to the virus).
It is a disease whose surface extends and who seems to be become endemic in more than one hundred country of Africa and Americas (of which the Caraïbe zone), but also in the Eastern Mediterranean, South Asia Is and Peaceful Westerner.

Only in 2001, there was more than 609.000 cases in Americas, from which 15.000 were hemorrhagic (approximately 2,5%).

Since the beginning of 2006, several countries of Caribbean announced cases: the Dominique, Jamaica, Surinam, St Lucia, Martinique, the Guadeloupe and Guyana.

Epidemics were also detected in Central America and of the South (approximately 128.200 the first 6 months notified cases of 2006).

The prevalence seems stable or in increase (as in El Salvador, in Paraguay, in Venezuela, and in certain parts of Brazil). Argentina knew some cases in 2006 whereas the virus had not been located since 2000. And the virus continues to prevail in its zone of natural endémie in Southeast Asia and Africa.

Contamination

It is to be noticed that the four Flavivirus DEN-1, DEN-2, DEN-3 and DEN-4). at the origin of the Infection from/to each other are very close, without there not existing of cross Immunité between these Virus of the dengue, which allows successive infections at the same individual.

It is transmitted to the man via Moustique S ( Aedes aegypti and in rare cases Aedes albopictus ) and is often spread in urban environment or semi-urban.

The mosquitos contaminate themselves by pricking the man, and seldom by vertical transmission of the mother to the egg (1 case out of 600).

The human being would be the principal natural basin of these viruses of the dengue, but also the disseminator of the disease.

Symptoms

Most of the time, it is a minor illness which, after one period of Incubation going from 2 to 7 days, product of the first Symptôme S approaching a Syndrome grippal severe (strong Fièvre, headaches, aches and Asthénie, etc) and brutal, which can last from 5 to 7 days. A fever lasting more than one week calls the diagnosis into question.

The nausea S and Vomiting S, sometimes intense, prevent any food, involving a syndrome of exhaustion and a Déshydratation with Collapsus, after 2 to 3 days of evolution (fortunately without real consequence, because answering well a intravenous Hydratation).

Very serious, fortunately rare hemorrhagic forms (less than 1 case for 1 000), would be due to an immuno-allergic phenomenon and would assign people having already had a dengue, but with another viral Sérotype (there are 4).

Treatment

There is for the moment (September 2005) neither preventive Traitement (vaccine) nor curative treatment of the dengue. The assumption of responsibility consists of symptomatic measurements:

to calm the pains and fevers (Paracetamol) in the common forms
to hydrate by venous way in the event of food intolerance (nausea) with dehydration
to possibly correct a state of Choc hemodynamic in the severe forms
of the transfusions of plates are sometimes nécessaires.

Convalescence lasts a fifteen or so days.

The dengue generally does not present complications, but there exist some severe forms and of rare hemorrhagic forms, which imply to consult a doctor and to avoid the self medication, in particular by the catch of aspirine which is formally contra-indicated, in the same way (but with a less level of proof) than the Anti-inflammatoire S not stéroïdiens, because they would raise the hemorrhagic risk.

Prevention

The prevention consists in being guarded against the punctures of mosquitos. It passes by the limitation of the number of the mosquitos, as for other diseases transported by this vector. With the Brazil, the preventive measures used are the elimination of the places of reproduction of the mosquito, the cleaning of the empty or occupied grounds by eliminating the bottles (containers being able to accumulate rainwater), the water tanks not - covers, the watery pots of plants, the drainage of the wet surfaces as well as the application of Insecticide in the infected districts.

To be immunized against the dengue, the 4 types should have been had: hemorrhagic and 3 nonhemorrhagic. Each time, the symptoms is more important. It is thus essential, for the young people, old, weakened or having antécédants of dengue to protect itself with repulsive body containing DEET (the lemongrass is not enough) to renew every 4:00, of the catches the repulsive ones, a mosquito net and long clothing with fallen the day.

In the West-Indian cemeteries, it is advised not to fill the vases of the plants with water but to replace the latter by wet sand which gives also good performances.

Seek

2007. According to the laboratory of the institute Leloir (Buenos Aires, Argentinian), ARN of the virus of the dengue would adopt a circular form as of its penetration in the infected cell. He would then directly be recognized by the enzyme of the cell carrying out the replication of the ARN, then translated into proteins by this same cell.

External bonds

dengue, on the site of the Institute Pasteur
dengue, on the site of WHO
Articles relating to the dengue on the site of the InVS
INVS 1/13/07 Dengue in the French departments of America, Not to January 12th, 2007
governmental Site of fight against the dengue in Singapore

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