The dengue, formerly known as influenza tropical or small malaria, is a viral infection, is endemic in tropical countries. A form trigger a hemorrhagic fever, the hemorrhagic dengue fever (DHF or for dengue hemorrhagic fever), is potentially fatal. The aggravation of hemorrhagic syndrome, usually for children under 15 years, leads to dengue shock (or DSS for dengue shock syndrome).

History

Described for the first time 1779, she was the cause of significant outbreaks in Australia (1897), the Seychelles (1926) in Tunis (1927) to Athens (1928) and Taiwan (1931).

Epidemiology

Then she was present only in Southeast Asia , it has been for some years in full progress in the rest of Asia , in Africa , in French Polynesia , and especially in South America , where the number of cases multiplied by 60 between 1989and 1993. The reasons are many:

• growing demographic important;
• creation of slums around cities;
• natural disasters ;
• impoverishment ;
• Slowdown of the mosquito eradication campaigns.

With 2001more than 609,000 cases were reported in the Americas, including 15,000 were bleeding.

Since then 2006, several countries in the Caribbean have mentioned cases: Dominique, of Jamaica, the Suriname, Saint Lucia, the Martinique, the Guadeloupe, Saint-Martin and Guyana.

Beginning 2008about 36,000 people in Rio de Janeiro have contracted dengue fever, overloading hospital emergency rooms. 50% of patients were under 14 years, 24 died. 2053 new cases have been reported for a single day, March 201.

In autumn 2009, the Atlantic, the small archipelago of Cape Verde has been swept for two months by an outbreak of dengue type 3 which, with over 20,000 cases of hit 5% its population, killing six people2.

The World Health Organization (WHO) estimates that between 50 and 100 million people are infected globally each year 3. Between 200,000 and 500,000 people suffer form bleeding, which kills 20,000 people a year.

It is the arbovirus most widespread, 40% of the world population is exposed to the virus.

Contamination

The dengue virus is transmitted to humans through mosquito and often spreads in urban or semi-urban.

Mosquitoes infect humans by biting, and rarely by vertical transmission from mother to egg (1 in 600). The human being is the main natural reservoir of dengue viruses, but also the disseminator of the disease.

It is noteworthy that the four flavi-viruses (DENV-1, DENV-2, DENV-3 and DENV-4) at the origin of the infection are very close to each other, without there of immunity cross themselves, and can cause successive infections in a single individual.

Symptoms

It is most often a mild illness after a period of incubation ranging from 2 to 7 days, produced the first symptoms of an approaching syndrome influenza and severe abrupt (high fever, headache, body aches, fatigue, etc.) can last 5-7 days. A fever lasting more calls into question the diagnosis.

Following 2-3 days of evolution, nausea and vomiting sometimes intense prevent any food, resulting in burnout and dehydration with circulatory collapse (thankfully no real consequence, for responding well to hydration intra-venous).

The hemorrhagic form due to a phenomenon would be immune-allergic and affect people who have already been infected by dengue virus belong to one of three other serotypes viral. This assumption is called “theory of facilitating antibodies, the antibodies induced by the first infection would facilitate the infection of monocytes during subsequent infection by a virus of another serotype. However, this hypothesis leads to predict a significant number of severe forms of the arrival of a serotype circulate in an area where another serotype, has not been verified in a number of epidemics. It is likely that the occurrence of hemorrhagic form is an event with multiple causes involving the field of HIV patient (prior infection with other serotypes of dengue or another flavivirus), general condition but also the nature of the virus- same (belonging to a particular phylogenetic subgroup).

After an incubation period of four silent days, and a spectacular invasion, the patient with “transfixed” by the pain and the sudden rise of temperature, the period of state presents a very characteristic hyperthermic two phases are separated in three days by an important two to three days, giving the line the classic look of a “saddle cantle.

The first phase is with temperatures reaching 40 relapsing 40.5 ° C hyperalgic with headache very violent. The second, with fever from 39 to 39.5 ° C, is characterized by a rash morbilliform or scarlatiniform very itchy.

It ends, the seventh to tenth day of illness, a sudden drop in temperature, with abundant sweat crisis. Then flake the skin into strips and begins a long and painful convalescence, sometimes with depressive phases.

Diagnosis

The rash and the typical curve of heat allow clinical diagnosis. The differential diagnosis is made first with the flu (particularly in the milder forms more gradual onset), the yellow fever and other arboviruses.

Treatment

There are currently (November 2009) or prophylaxis (vaccine) or cure for dengue fever (viral infection). The management consists of supportive measures:

• soothe pain and fever ( paracetamol or ibuprofen ) in the common forms
• hydrated through venous if food intolerance (nausea) with drying
• possibly correct a state of hemodynamic shock in severe
• The transfusion of platelets is sometimes necessary.

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Convalescence takes a fortnight.

Dengue fever usually presents no complications, but there are some severe and rare hemorrhagic form, which involves a doctor and avoid self-medication, including the taking of aspirin -cons who are formally specified, so (but with a lower level of evidence) that the anti-inflammatory non -steroidal, because they would increase the risk of bleeding.

Prevention

The prevention is to take precautions against mosquitoes that bite during the day. It involves limiting the number of mosquitoes, as for other diseases carried by this vector. In Brazil and Guyana , the preventive measures used were the elimination of mosquito breeding sites, cleaning up vacant lots or busy removing bottles (containers that can collect water from rain), water tanks not cutlery, pots of aquatic plants, drainage of wet areas and the application of insecticide in the infected quarters.

To be immunized against dengue, it must have been 4 types: a non-hemorrhagic colitis and 3. Each time the symptoms are more important. It is therefore essential for the young, elderly, debilitated or a history of dengue protect themselves with a body-based repellent DEET (citronella is not enough) to be renewed every 4 h, taken repellents, a net and long clothes at dusk.

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