Hello today we're going to talk about all the viral diseases of the tiger mosquito
dengue, chikungunya, Zika and Vest.
We’re going to deal with dengue first, which is an emerging viral infection called
also tropical flu.
Dengue is an enviro tropical herb transmitted by the daytime mosquito bite of
rudeness, infected with the dengue virus.
It is an emerging disease characterized by its continuous geographic expansion and
the increasing increase in its incidence is a growing cause of morbidity in the
traveler. Dengue fever also poses the threat of secondary spread in
temperate regions, where the species of Albopictus are implanted is a disease with
mandatory declaration which is the subject of an anti-dissemination plan aimed at
identify any imported case in period would transfer MICC auto native case on the
territory. Epidemiological reminder.
Dengue viruses are arthropod born virus arboviruses that belong to the
family of Flavy Zirides genus Flavy virus.
These are herren viruses, with a positive polarity of 11,000 nucleotides, including
there are four different serotypes of a DN2 DN3 Dhainaut 4.
Indeed, after infection with one of these serotypes, the immunity conferred for this one
is final. But there is no lasting cross-immunity with other serotypes.
An individual living in an epidemic demo zone can therefore, in theory, contract four times
the of Ang. Man is the main reservoir.
It plays the role of amplifying host and disseminator of the virus in Asia and
Africa. Non-human primates are possible reservoirs.
Dengue viruses are transmitted from human to human by the bites of females from
infected mosquitoes belonging to the Qualified family and to the genus Edessa.
They are characterized by their strong preference Apic and the human being between Ponfilly and
their daytime activity.
Édesse et Petit is the main vector of dengue in the world.
This mosquito native to Africa is now present in the intertropical zones of
all continents and it remains able to recolonize areas where it was eradicated,
like Mediterranean Europe, Edessa albopictus, nicknamed the tiger mosquito and the same
vector that transmitted the Zika and chikungunya virus, native to the forests of the Southeast
Asian. This species is able to colonize temperate countries, because its eggs can
enter diapause if weather conditions are unfavorable.
Its presence has been proven in the South East of France for about 15 years.
Other vectors, like Édesse, Paulino, y Hensies can also be blamed.
Rare cases of maternal-fetal transmission and healthcare associated infections
accident of exposure to blood, transfusions, organ transplantation have been described.
This world map illustrates the average number of cases reported from 2010 to 2016.
Geographical distribution of dengue.
World Health Organization says lack of data available in Africa
Sub-Saharan does not mean the absence of virus circulation.
Epidemiological importance in the world.
Four hundred million cases annually.
The disease is now endemic in more than 128 countries in Africa, the Americas, the
Eastern Mediterranean, Southeast Asia and the Western Pacific, with a
predilection for urban and semi-urban Fily Vector warehouses.
Nearly 3.9 billion people are exposed to it and it is currently estimated that
annual cases at 4,100 million, including 500,000 hospitalized cases and five hundred deaths,
mainly in children.
Dengue fever, the most common in travelers.
The risk of acquiring dengue varies according to the destination visited, the season and the
level of epidemic activity.
It is the second cause of hospitalization for fever upon return from the tropics
after malaria, the first cause of fever when returning from Southeast Asia.
Imported cases pose risk of virus introduction and local spread
secondary, indigenous case in temperate countries where the competent vector, Édesse
albopictus, is implanted, as has been described in Europe Italy, France, Croatia, in
United States, China and Australia.
The clinical course is generally favorable.
Severe forms are exceptional in travelers.
Classification of cases of dengue fever by severity, dengue fever with or without warning signs.
Severe dengue. Criteria defining dengue.
Probable dengue HIV or stay while traveling in an endemic area of ​​Ang.
Presence of fever and two of the following criteria nausea, vomiting, rashes
skin, pain, positive signs.
The. Any significant laboratory confirmed IMG warning sign in the absence of signs
plasma leak warning signs, pain or tenderness on palpation
abdominal, persistent vomiting, accumulation of clinical fluids, bleeding from
mucosal level, lethargy, hepatic megalis anxiety greater than 2cm, elevation of
hematocrit measured in the laboratory occurring at the same time as a rapid decrease
platelet count requiring close observation and intervention
medical. Criteria for severe dengue fever, severe plasma leakage resulting in shock.
JN liquid accumulation
With respiratory distress.
Severe bleeding as assessed by the clinician.
Severe organic damage.
Rate of Asa or Hepatic Hallegatte greater than or equal to 1000.
Central nervous system.
Deterioration of the state of consciousness.
Damage to the heart and other organs.
Typical or classic shapes.
After an incubation period of 4 to 7 days, extreme 2 to 14 days, a fever appears
brutal. This high fever lasts from 2 to 6 days and is associated with intense asthenia and
an analgesic component retro orbital headache, honey, arthritis, JEE, low back pain.
An example of smudged times or macular opaque pulpy facial trompe oculars is present in
half of the cases are more pure than the lower limbs.
It can be of palmar or Plantar location and originated.
Digestive signs may be observed anorexia, nausea, vomiting, pain
abdominal and diarrhea.
Minor bleeding signs, the prognosis of which is uncertain, are possible.
Fart chi. Signs of the Pura Epices turnstile, Taxibus, Junji Voragine.
The turnstile sign is an appearance of Pétée Chi following the application of a
careful cuff swollen around the arm.
Taken into account in the classification of the World Health Organization WHO, S
shows an increase in capillary fragility.
It is neither sensitive nor specific.
The presence of hepato-splenomegaly and lymphadenopathy is described a gauzy dose and
mismatch. Member ideas are possible in these benign forms.
The clinical course is favorable in seven to eight days.
Prolonged residual asthenia can be observed in severe forms and classification
OMVS. The new MS water classification of 2009 distinguishes three entities the
probable dengue, dengue with warning signs and severe dengue, defined by
the existence of at least one of the following criteria.
A capillary leak syndrome responsible for shock or respiratory distress.
Severe hemorrhage according to the clinician.
Visceral involvement, including hepatic aspartame, HAS Transfers terminals, Razac.
Alani Amino will hastily transfer more than 1,000 international units per liter.
Neurological disorders of cardiac alertness.
In practice, in 2 to 4 cases, a plasma leak syndrome appears after 4 to 7
days of classic dengue at the time of thermal effervescence.
During this critical phase from the fourth to the sixth day, the observation of signs
alert whose prognostic value is recognized justifies hospital treatment.
Variable severity plasma leak syndrome results in a concentration
hematocrit elevation over 20 years Minami hypo albus.
It lasts 2 to 3 days and rarely results in shock 1% of cases of poor prognosis.
Ecology, which can detect a subclinical plasma leak, effusion of
serous and or of the vesicular wall, facilitates the early identification of the forms
serious. Hemorrhagic manifestations can complicate this situation.
They are most often secondary to a multi visceral failure, unrelated to
thrombosis pennies in the absence of early management.
The lethality of hemorrhagic forms is high.
Other rare visceral complications have been described.
Hepatitis, rhabdomyolysis, myocarditis, encephalitis, honey, leet syndrome
Guillain-Barré, activation syndrome, macrophages, tics, spleen rupture.
Some patients at risk of serious forms justify specialized care
extreme ages, pregnant women in the third trimester, associated comorbidities,
sickle cell anemia, diabetes, immunosuppression, bleeding disorders.
The risk of serious forms is increased in previously exposed migrants and expatriates
to dengue secondary infection by a serotype, hydrologist summer, diagnostic approach,
diagnosis of presumptions, epidemiological arguments.
Nonspecific asymptomatic or symptomatic pauci forms are frequent in
metropolis. If it is obvious to suspect.
After a stay in an endemic region of Southeast Asia, the Antilles, Guyana, but also
Sub-Saharan Africa, in the absence of established indigenous homes, you have to think about it
evocative symptomatology, because the transmission could be done from cases
symptomatic clinical arguments due to the short incubation period.
The diagnosis of dengue is unlikely.
In case of fever evolving for more than 15 days or starting more than two weeks after
the return from an endemic area, the presence of an exhilarating Meïté evocative but not
specific. Biological argument the words Gramm is the main orientation exam and
feedback. It should be done as soon as possible.
It classically highlights a beautiful penis thrombosis which has prognostic value
when it is early or suddenly gets worse.
A penis lecorre with a false penis and neutropenia often deep and lasting.
An Eauze hyper lymphocyte with the presence of atypical secondary appearance lymphocytes
is possible. She discusses the other causes of mononucleosis, vik, primo syndromes
Hash hash human immunodeficiency virus infection in particular.
And the increase in hematocrit is a marker of enamel, a concentration that can
translate a plasma leak that occurs between the 3rd and the 8th day.
An increase of more than 20 percent in the absence of dehydration is a sign of
gravity. Reactive protein C is most often normal or low less than 10
milligrams per liter.
The abnormalities of the hepatic balance are constant cito lysis hepatic Azza superior to the
spleen, which is a sign of severity.
If the Citeaux lyse is important Azza or greater than 1000 international units per
liter, more rarely colet stasis.
The rise in muscle enzymes rhabdomyolysis is classic.
Acute renal failure, most often functional Japanese Latrémouille can
to be observed. Coagulation anomalies with isolated elevation type of
Inactivated circulating anticoagulant headache is common.
The trombin rate is normal, except in the event of disseminated intravascular coagulation or
hepatocellular insufficiency of lipo albumin like and increased ferritin
orchard plasma 5 d 6 reflect the increase in vascular permeability.
The diagnosis of certainty of the disease is essential for clinical management
and the implementation of epidemiological surveillance measures.
It is based on an understanding of the short-term character of viremia on average five days
which is detectable between the second day before and until the seventh day after
onset of clinical signs.
Direct diagnosis.
Diagnosis can be based on direct diagnosis by detecting the virus in the blood
of the patient or more rarely in the cerebrospinal fluid or possibly in
necromancy. Three different techniques reserved for the early 5-7 stages
sick days can be used.
Molecular biology techniques are the most effective and constitute
now the benchmark.
They detect the viral genome by reverse transcriptase of chain polymerases.
RT reactions
PCR and RT
Real-time PCR and identify the serotype due to epidemiological interest detection
of viral antigens Annezin antigen, this protein specific for dengue viruses and
present at high concentrations in the serum of infected persons between
first and seventh days of illness.
ELISA and rapid immuno chromatographic tests are currently available
in the form of strips or cassettes.
These specific tests of 86 to 100 percent depending on the studies, have a sensitivity
variable according to the serotypes of the virus in question and in case of secondary dengue.
In fact, the use of these rapid tests is not recommended in endemic areas.
Their use should be strictly limited to the early stage of the disease and any
negative result must be imperatively checked by a molecular test.
Isolation of the virus by culture on mosquito cell lines, long technique
and complex, is reserved for level 3 LSB 3 biological safety laboratories, such as
the National Reference Center for Indirect Diagnostic Arboviruses.
Antibody detection is preferred from the fifth day of illness.
It is based on the detection of immunoglobulins of type M, I, GM, Elisa of type capture and
10 G specific ELISA and indirect according to their kinetics of appearance.
Over time, during a primary infection, GMs appear five to six days and
YG G 7-10 days after symptom onset, ISIS GM reaches peak
maximum in 2 to 3 weeks and can sometimes persist up to 6 months after the first
infectious episode.
Secondary infection characterized by contact with an enterologic virus, the Y
Jay-Jay appear earlier and their rate gradually increases for approximately
two weeks. ISIS GMOs are detected at lower rates and, in some cases,
may be fleeting or even absent.
The overall antibody titer increases very rapidly from the acute phase of infection
and these antibodies have significant cross-reactivity towards other antigens of
Flavy virus.
It is therefore a probabilistic diagnosis.
The observation of a rise in the title of YG
An increase of a factor of 4 is rarely observed due to the lack of a second sample
performed during the recovery period.
Biological diagnosis strategy the choice of diagnostic technique to be implemented
work is done first according to the date of onset of clinical signs.
If the collection is early less than the fifth day following the onset of
symptoms, these are the direct RT methods
PCR and detection of the Annezin antigen which are indicated between D5 and D-7.
Direct methods and serology are used after D-7.
Only the serology remains indicated by insisting on the importance of a second sample
a minimum of 15 days apart.
9 are then involved in the choice of diagnostic test.
The geographic area in which the contamination took place and in which it is located
the patient which may be different, for example symptomatic infections after
a return trip and finally in a given geographical area.
The epidemiological situation, the availability of tests and the
clinical situation of the patient care and treatment.
In the absence of specific antiviral therapy, treatment for dengue fever is
only symptomatic.
It combines rest, hydration and analgesics based on paracetamol, a risk
hepatitis. Aspirin and anti-inflammatory drugs are contraindicated, a risk
hemorrhagic and renal.
The patient and his entourage must know the warning signals in the implantation area
of vectors. The installation of vector protection around the patient
mosquito net is recommended during the febrile phase.
Any dengue occurring in a subject with a risk area for venous thrombosis
severe less than 100,000 per cubic millimeter and a fortiori at least one warning sign,
justify hospitalization in a specialized center with a
intensive care. Shocks are treated by an early volume expansion.
Tabloid attacks or colloids at the initial dosage of 10 to 20 milliliters per
kilograms per hour are equivalent in efficiency.
A brief filling, 24 to 48 hours, guided by the hematocrit clinic and written
is most often sufficient.
A risk of overloading by accumulation of solutes in the interstitial spaces.
Severe haemorrhage is due to transfusion, globular concentrates and
platelet. Vaccine.
The live attenuated vaccine bows going into Galaxia, which has a license to
placed on the market since December 2018, is indicated in subjects aged 9 to 45 years,
living in an endemic area and having a history of infection with the Ang virus in
France. According to the recommendations of the High Authority for Health, it is neither recommended nor
among people residing in overseas departments, or among travelers
making it into endemic areas.
Limited efficacy on certain serotypes and sometimes severe undesirable effects
reduce his interest.
Vector prevention and control measures.
Dengue prevention is based on two complementary pillars: the application of
personal vector protection measures covering or even impregnated clothing
insecticide, treated nets, skin repellents and insecticides suitable for
the age, type and duration of stay and the fight against hoppers in the
endemic regions or colonized by ZS in daytime activity.
Early in the morning and above all, an afternoon of the vector should lead to favor these
preventive measures at these times.