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Etiology

Pathogenesis

Epidemiology

Clinic

From the 1st day, algic syndrome is expressed, especially severe retro-orbital headache, as well as pain in muscles and joints (gait without bending the legs - “dandy”, “dandy”). There may be swelling and redness of small joints, nausea and vomiting.

Hyperemia and puffiness of the face, injection of scleral vessels, general erythema (“red fever”) and skin hyperesthesia are distinct. Peripheral lymph nodes are enlarged.

Tachycardia is noted, and from the 2-3rd day of illness - bradycardia. Leukopenia and thrombocytopenia are detected in the blood.

The internal organs are not significantly changed. By the 3-4th day the temperature drops, which is accompanied by heavy sweat.

The condition improves, but myalgia, arthralgia, typical gait, severe weakness (“lead cape on the shoulders”) persist. After 1-4 days, the temperature rises again, the main symptoms of the disease intensify. The second wave is easier and lasts 2-3 days.

In 80-90% of patients, during the second wave or immediately after a drop in temperature, a profuse maculopapular (“flying measles”), urticarial or scarlet-like (“rheumatic scarlet fever”) rash appears, accompanied by itching and leaving pityriasis-like peeling. The total duration of the disease is 6-10 days.

Convalescence lasts for 3-8 weeks (asthenia, pain in joints and muscles). The hemorrhagic form is more severe.

In addition to the described clinic, during the first febrile wave, more severe intoxication is observed. In most patients, the size of the liver increases.

From the 2nd day of illness, hemorrhagic syndrome is expressed to varying degrees: petechial rash, hemorrhagic purpura, extensive ecchymosis, bleeding gums, nasal, pulmonary, and gastrointestinal bleeding. In 20-40% of patients, infectious-toxic shock develops with symptoms of depression of the central nervous system, cardiovascular failure, blood thickening, hypoproteinemia, oligo- or anuria.

The mortality rate for classic dengue fever does not exceed 0.1-0.5%, for hemorrhagic fever it reaches 5%, and among children - 15-20%.

Differential diagnosis

In addition, pappataci differs from dengue by Taussig's symptom and the always present injection of scleral vessels in the form of a triangle at the outer corners of the eyes (Pick's symptom). The initial symptoms of malaria - chills, rapid rise in temperature, headache and muscle pain, leukopenia - may resemble the symptom pathology of the first dengue fever wave. However, malaria is characterized by an early increase in the size of the spleen and liver, subsequent periodicity of characteristic febrile attacks (3- and 4-day malaria), and a long duration of the disease. Dengue is also distinguished from malaria by a profuse rash, polyadenitis, a typical gait, and the change from tachycardia to bradycardia.

The last two symptoms and the absence of jaundice are the main ones features hemorrhagic forms of dengue. The diagnosis is sometimes determined through laboratory tests. Dengue fever differs from influenza in its seasonality associated with the flight of mosquitoes, the absence of catarrhal symptoms, and appearance and the gait of patients, the presence of rash, polyadenitis. The presence of a rash with dengue makes it necessary to differentiate it from measles, scarlet fever, and rubella.

Dengue is distinguished from these diseases by severe headache, retro-orbital pain, muscle and joint pain, and a characteristic gait. In addition, unlike measles, dengue fever does not have pronounced catarrhal symptoms of the upper respiratory tract (cough, runny nose), Velsky-Filatov-Koplik spots, or a clear phasing (by day) of rashes. The measles rash is not accompanied by itching. Dengue differs from scarlet fever by the absence of a bright sore throat, severe pain when swallowing, a pale nasolabial triangle, and a “crimson” tongue.

With scarlet fever, the fever does not have a two-wave character; there is leukocytosis in the blood, not leukopenia. Leptospirosis from dengue help to distinguish the duration of the disease, symptoms of liver and kidney damage, an increase in the size of the spleen, the appearance of jaundice, typical “scleritis”, leukocytosis in the blood, the presence of leptospira in the blood and urine.

Prevention

Diagnostics

Attention! The described treatment does not guarantee positive result. For more reliable information, ALWAYS consult a specialist.

The content of the article

Historical Data of Dengue Fever

Etiology of Dengue fever

Epidemiology of Dengue fever

Pathogenesis and pathomorphology of Dengue fever

Dengue Fever Clinic

Classic shape

Hemorrhagic form

Diagnosis of Dengue fever

Specific diagnosis of Dengue fever

Dengue fever treatment

Prevention of Dengue Fever

Specific timing of exacerbation of the epidemiological situation is predicted as follows:

The carrier of the infection is mainly the Egyptian biting mosquito - Aedesaegypti and some of its other relatives. And for breeding, this type of mosquito, like others, prefer to choose stagnant bodies of water or, as they often say, wetlands. (*But these can also be small tanks, as well as showers and toilets.) Thus, the peak of the epidemic coincides with the beginning of the rainy season - April May(but it’s better to focus on the rain), and subsequently the situation subsides a little, but there is still a chance of infection. The mosquito is only a carrier - there is no need to blame it for all the bad things. The source of the disease is humans and some primates. Therefore, when the number of carriers decreases due to the actions of doctors and natural processes, then the epidemiological situation decreases.

There is no warning as such about the beginning of the epidemic, the locals already know. If they sit down and make a notification, they will say a couple of times on the news and that’s enough. Previously, this problem was more acute in Thailand, there was a high mortality rate, not like now, then the notification was as necessary. And now local medicine has learned to recognize and cope with this disease well.

How to protect yourself?

It’s very simple to protect yourself, avoid the carriers – the Egyptian biting mosquito – Aedesaegypti:

Egyptian biter, distinctive feature is the presence of white dots on the black body.

1. Most of all, the mosquito loves to be in a shady area.

2. Interesting feature The mosquito is that most of all it loves human blood and the blood of primates.

3. The most favorite breeding places for mosquitoes are places of stagnant water - wetlands or water filled with organic decay products, various leaves, grass, etc. But the most dangerous of them for humans can be the shower and toilet.

4. The increase in the population of this mosquito is facilitated by uncontrolled urbanization, accompanied by the emergence of urban areas without a centralized sewerage system, littered with household waste, many components of which, for example cans, serve as an excellent breeding ground for mosquitoes;

5. As a precaution, it is recommended to wear clothes with long sleeves, and use mosquito spray.

Back in 1635, the first outbreak of dengue fever was recorded in the Caribbean. Since then, over the course of three centuries, the disease has periodically made itself felt. Most often, fever outbreaks occur in the tropics. However, thanks to the visits of modern tourists to exotic countries, pathology is often diagnosed in various parts of the world. Today, a disease that was rare in the past has become one of the most common arboviral infections.

Dangerous tropical disease

Dengue fever is an acute viral pathology. The disease is accompanied by symptoms characteristic of the flu, or the presence of a hemorrhagic rash over the body.

The main carrier of fever is the mosquito. It is he who is initially the carrier of the pathogenic microorganism. Even one bite is enough to infect a person.

The disease is most often diagnosed in children. The percentage of patients is especially high among infants and children over 3 years old.

The course of the fever is quite severe. Patients experience increased body temperature, severe intoxication, muscle and joint pain, and inflammation of the lymph nodes. The presence of bleeding and a characteristic rash indicates the development of a hemorrhagic form of pathology (more severe).

Dengue fever, taking into account the symptoms and timing of its progression, is called: bone-breaking fever, seven-day fever, joint fever, five-day fever. Some even call it giraffe fever.

Pregnant women infected with Dengue fever have an increased risk of fetal death or spontaneous miscarriage.

In addition, the insidiousness of the disease lies in the ability of the virus that has infected the mother’s body to penetrate the fetus through the placenta. In this case, the child is already born with antibodies indicating the classic form of the disease.

If the baby has inherited immunity from the mother to one of the types of fever virus (there are 4 subtypes in total), then re-infection of the baby is very dangerous. After all, such an infection leads to the development of a severe form of pathology in the baby - hemorrhagic. It is one of the main reasons for high infant mortality in tropical countries.

If an infection is introduced into a baby’s body for the first time (as a rule, this is observed in preschoolers), then the pathology is relatively easy. Severe symptoms characteristic of adult patients practically do not occur.

Video about the disease

Classification

Sometimes the fever is quite mild. However, some patients experience a severe form, which can even lead to death.

Considering these features of the pathology, doctors distinguish two main forms of fever:

1. Classic. This disease has a relatively mild course. The classic form is diagnosed during primary infection. That is why such a pathology is most often found among tourists eager to see exotic countries.
2. Hemorrhagic. A severe form of the disease, characteristic of the local population. It is distinguished by the severity of clinical manifestations and a high risk of death. It develops only against the background of secondary infection. Immunity plays a special role in the appearance of this form. After the initial infection, antibodies are produced. They are the ones who force the body to react sharply to re-infection. However, you can get sick with the hemorrhagic form only in the period from 3 months to 5 years after the initial infection.

Causes and routes of infection

Dengue fever is a viral pathology with 4 subtypes. Each of them is capable of triggering the development of a disease, which during primary infection proceeds favorably.

The main carrier of the virus is the mosquito. After an insect bite, a person becomes a carrier of the infection. It is not contagious to people around it, but it becomes an excellent source for the virus to infect other mosquitoes.

Predisposing factors

Understanding the mechanism of human infection, we can safely say that you can only become infected with Dengue fever through contact with infected mosquitoes.

And this is possible in a number of the following cases:

• tourism to countries in Africa, the Caribbean, Southeast Asia, Oceania;
• visiting places with a negative epidemiological situation for this pathology;
• non-compliance with prevention rules protecting against insect bites.

Symptoms and signs of various periods of the disease

Seven days of Dengue begins suddenly. As a rule, the incubation period (the time after a mosquito bite until the first clinical manifestations) can be 3–15 days. In most cases it lasts 5–7 days.

Pathology usually begins with a slight malaise, which manifests itself:

• headache;
• feeling overwhelmed;
• increased weakness.

6–10 hours after such a deterioration, the main clinical manifestations of fever develop. Symptoms of the pathology completely depend on the form of the disease.

Symptoms of classic fever

This form of the disease is called bone crushing (or articular). The pathology is characterized by a benign course.

It causes the patient:

1. Hyperthermia. This is the main sign of the disease. Temperatures can rise to very high numbers. This reveals the cyclical nature of this symptom:
   • high fever accompanied by rapid heartbeat is observed for 3 days;
   • over the next 2–3 days there is a sudden drop in temperature. Bradycardia appears, the heart rate can decrease to 40 beats/min;
   • the temperature rises sharply again. Hyperthermia is accompanied by increased heart rate. These symptoms continue for another 3 days;
   • by the ninth day there is significant improvement. The patient recovers;
2. Headache. Severe pressing discomfort is noted in eyeballs. Redness of the eyelids may occur. Inflammation of the mucous membrane of the eyes occurs. Photophobia sets in.
3. Arthralgia, myalgia. Patients experience severe muscle and joint pain. Tension in the tissues, aches, and stiffness appear. Particularly disturbing are the knees, sacral area and back.
4. Enlarged lymph nodes.
5. Symptoms of intoxication. Patients complain of severe weakness and dizziness. Some experience nausea and vomiting. The patient's sleep is disturbed and his appetite disappears. There may be a bitter taste in the mouth. Sometimes the pathology is accompanied by a runny nose.
6. Rash on the body. It usually appears on days 5–6. The rash initially appears on the inner areas of the shoulders and chest. Then the rash covers the entire torso, followed by the limbs. The rash consists of red papules (lumps that rise slightly above the skin) and spots. This rash causes severe itching in the patient. After it, areas of peeling remain on the skin.

The classic form of Dengue fever, which occurs in a severe form, can provoke severe vomiting, impaired consciousness, and delirium in the patient.

Symptoms of hemorrhagic form in a child

The course of hemorrhagic fever is much more severe. It is this form that often leads to death. Doctors call this hemorrhagic type of pathology severe dengue.

With this disease, patients do not experience muscle or bone pain. However, the symptoms of fever are quite painful:

• cyclical hyperthermia (increase and decrease in temperature is the same as in the classical form);
• headache;
• swelling of the face, redness of the mucous membranes;
• pain, sore throat, cough;
• severe chills;
• abdominal pain, profuse diarrhea;
• feeling of nausea, repeated vomiting, in some cases with streaks of blood;
• enlarged liver, pain occurs when palpating the right hypochondrium;
• the appearance of a red rash on the inner surfaces of the elbows and knees;
• spread of rashes over the entire body within five days;
• itchy rash accompanied by peeling;
• increased breathing;
• increasing weakness.

After 2–7 days, normalization of body temperature may be observed. These symptoms indicate a healing process.

Disease severity

To assess the severity of the hemorrhagic form, WHO proposed classifying the pathology by stage.

There are 4 degrees of fever:

1. Against the background of hyperthermia with general intoxication, initial signs characteristic of hemorrhagic syndrome begin to develop. With slight compression of the skin in the elbow area, hemorrhages appear.
2. A slight decrease in temperature is typical, usually to subfebrile levels. The patient begins to bleed spontaneously. They can be both external and internal. Bleeding gums are possible. Patients may experience nasal, uterine (in women) bleeding. Sometimes hemorrhages are observed in the brain, stomach, and intestines.
3. This is the degree of shock syndrome. The patient's condition is complicated by circulatory insufficiency (weakened blood flow). The patient becomes agitated and extremely restless. Blood pressure drops sharply and the heartbeat slows. The patient begins to develop respiratory failure.
4. Blood pressure drops so much that it is almost impossible to measure it. The patient enters the stage of deep decompensated shock.

Signs of severe form

If the hemorrhagic form is severe (degree 3–4), then to the one described above clinical picture the following symptoms are added:

• the torso is warm, and the limbs are cold, covered with sticky sweat;
• the face is pale, lips and limbs become blue;
• pinpoint hemorrhages can be observed throughout the body ( greatest number in the area of ​​the hands, forehead, feet);
• convulsions and bloody vomiting appear.

Diagnosis of dengue fever

For correct setting The diagnosis of Dengue fever is initially assessed by:

1. Epidemiological situation. The doctor finds out whether the patient was in an area with high level morbidity due to this pathology.
2. A set of symptoms of a disease. Based on the clinical picture, the development of fever can be suspected.

Then comes the turn of laboratory tests, which make it possible to accurately establish the diagnosis and differentiate Dengue fever from other diseases:

1. Detection of the virus. The PCR diagnostic method is used. It makes it possible to accurately identify the causative agent of the disease. But such an analysis can be carried out only in the first 2-3 days of fever.
2. Determining the subtype of the virus. The same PCR method is used. Determining the subtype of the virus is necessary for emergency prevention. It consists of introducing immunoglobulin into the body of a person who has already had this subtype of fever and has a strong immunity to it.
3. Determination of antibodies in blood. Based on the presence of specific antibodies in the blood that are designed to fight the virus, a doctor can diagnose a fever.
4. Blood analysis. It shows a decrease in platelets, an increased volume of blood cells and hemoconcentration (blood thickening).

Differential diagnosis is carried out with the following diseases:

• malaria;
• yellow fever;
• infectious-toxic shock in bacterial pathologies (sepsis, meningococcemia).

Treatment methods

If a virus is detected in a patient’s body, doctors immediately send him to the infectious diseases or intensive care unit of the hospital.

No specific treatment for the pathology has been developed. Therapeutic measures are reduced to:

• reducing the severity of negative symptoms;
• preventing the development of complications;
• support of the body.

Great importance is given to the treatment of pathology dietary nutrition and drinking plenty of fluids. During illness, it is recommended to adhere to a gentle diet. It is useful to drink mineral waters: Morshynskaya, Borjomi, Essentuki No. 4, Truskavetskaya.

Classic form therapy

The following groups of drugs are used in therapy:

1. Antipyretic. Various drugs may be prescribed, except those that can cause bleeding (for example, Aspirin, Ibuprofen). Paracetamol is good for reducing fever and eliminating pain during Dengue fever.
2. Painkillers. To eliminate pain, Dexalgin (intramuscular) can be prescribed.
3. Antibiotics. This treatment is used when bacterial complications develop. Cefepime, Ceftazidime, Cefoperazone may be prescribed.
4. Anticoagulants. These medications are designed to protect against blood clots. They prevent blood clotting. Heparin is usually recommended. For mild forms of the disease, the following may be prescribed: Enoxaparin, Nadroparin, Dalteparin.
5. Antihistamines. To eliminate itching, doctors recommend taking Terfenadine, Cetirizine, Ebastine.
6. Vitamins. The patient may be included in therapy using the multivitamin complex Supradin.
7. Medicines to remove toxins. To cleanse the body, it is recommended to take Sorbex. Prescribe physiological solutions (intravenously): Sodium chloride, Ringer's solution.

Drugs to eliminate fever - photo gallery

Paracetamol is excellent for reducing fever in dengue fever
Dexalgin eliminates pain
Heparin prevents blood clotting
Ebastine perfectly relieves itching
Sorbex helps cleanse the body
Ringer's solution is recommended for removing toxins

Therapy for hemorrhagic form

Treatment of the disease is carried out in intensive care conditions. The following measures are indicated for the patient:

1. Drip administration of saline solution (Ringer's, Sodium chloride), vitamins and glucose.
2. Transfusion of plasma or plasma substitutes.
3. Inhalation of humidified oxygen.
4. Prescription of glucocorticosteroids. The drug Prednisolone is effective.
5. Administration of anticoagulants. Heparin is usually prescribed. It is administered intravenously.

Depending on the patient’s condition, symptomatic treatment is prescribed to prevent the development of respiratory failure and pathologies of the cardiovascular system.

Prognosis for treatment of the disease, complications and consequences

The classic form almost always has a favorable prognosis. The mortality rate in this case is 1%. This disease has a tendency to heal itself.

However, if hyperthermia is not dealt with, the following complications are possible:

• heatstroke;
• overheating of the body.

The prognosis for grade 1–2 hemorrhagic fever is also favorable. But if the patient begins to develop shock syndrome, then his situation worsens significantly. With this form, the risk of death is already 10%.

The disease can lead to quite serious consequences:

• dehydration, disturbed blood composition;
• brain pathologies - meningitis, encephalitis;
• inflammation of the middle and inner ear, parotid glands;
• pneumonia, bronchopneumonia;
• respiratory failure;
• damage to the nervous system - psychosis, polyneuritis.

Post-infectious immunity

After an illness, a person develops immunity. But it is short-lived and lasts about 5 years. In addition, immunity develops only to the subtype of the virus that provoked the fever.

After being bitten by a mosquito infected with a different serotype, the immune system is unable to protect the person from developing the disease. Such re-infection leads to a hemorrhagic form.

Prevention

Most effective method prevention of infectious pathologies is vaccination. Unfortunately, there is no vaccine against dengue fever. It is known that several vaccines have already been developed and today they are being tested.

Given the lack of licensed drugs to avoid infection, it is recommended to resort to measures aimed at protecting against insect bites.

For these purposes, perform the following actions:

1. Patients must be kept in an isolation room, the windows of which must be covered with mosquito nets.
2. It is recommended to use mosquito repellents in the form of sprays and creams.
3. Mosquito nets must be installed on the windows of your home.
4. In epidemic areas, spraying insecticides to kill mosquitoes is recommended.
5. All vehicles and cargo arriving from exotic countries, must undergo disinfestation.

Dengue fever is one of the pathologies that can be fatal. However, with timely consultation with a doctor and adequate therapy, even this serious illness can be cured.

Dengue fever, or joint fever, is a naturally occurring infectious disease caused by a group of arboviruses (a type of virus transmitted by arthropods). Depending on the form, it occurs like the flu with a rash on the body, myalgia and joint pain, or is accompanied by hemorrhagic syndrome, spontaneous bleeding, shock, collapse, and often leads to death. The disease is caused by the dengue virus, which is transmitted by tropical mosquitoes. There are no etiotropic drugs that affect it, so therapy is based on eliminating symptoms and the use of hemostatic and anti-shock measures.

Features of the disease

Dengue fever is a vector-borne disease caused by the virus of the same name, found in tropical and subtropical climatic zones. Cases of mass infection have been identified in 110 countries, Australia, Africa and Oceania, on the South American continent, southeast Asia, and the Mediterranean coast.

Outbreaks of epidemics depend on the seasons and are observed during the rainy season. In endemic areas, usually in cities, up to several hundred thousand people are infected per year; precedents are recorded outside the hotspots during the migration of already infected people or the importation of carrier mosquitoes.

Fever manifests itself in two independent forms, differing in symptoms and consequences of infection:

• Classic. It is accompanied by a feverish state, pain in the joints and muscles, the development of lymphadenitis (inflammation of the lymph nodes) and leukopenia (decreased white blood cells).
• Hemorrhagic. The disease is severe and is characterized by impaired vascular permeability. Hemorrhagic diarrhea develops due to a decrease in the number of platelets in the blood (thrombocytopenia) and a clotting defect. A decrease in circulating blood, proteins and electrolytes causes disturbances in organ function, which leads to shock, becoming the main cause of high mortality rates from the disease (in some areas - up to 50%).

There are cases of atypical and asymptomatic course of the disease, which is associated with the characteristics of the genes of individual individuals.

Causes

Dengue virus

Fever develops as a result of invasion of the human body by an arbovirus from the family Togaviridae, genus Flavivirus. Science knows the virion serotypes from DEN-1-2-3-4, the fifth was established recently, in 2013. All of them differ in antigenic structure, differentiation occurs by the neutralization reaction and HRT titers.

Each strain causes similar symptoms of disease and can provoke both types of fever. Types 2 and 3 have the greatest cytopathic effect.

After the illness, immunity to the pathogen is developed for 2 years and resistance to other types for 2 months.

It has been noted that the hemorrhagic form often develops in people who have previously been ill when they are re-infected with a different serotype of the virus. Disorders of hemostasis, activation of complement and other parts of the system are most likely associated with the immune response and its damaging effects.

The shape of the dengue virus is spherical, the diameter is approximately 40-45 nm. It has an additional lipid bilayer with surface projections and single-stranded unsegmented RNA. Close relatives of the virion are the encephalitis, yellow fever, West Nile, and Zika viruses. All these species are transmitted by arthropods and are therefore called arboviruses.

Extracellular agents are unstable to heat and die at a temperature of about 60 °C, but when dried or frozen to -70 °C they remain active for up to 10 years. They are sensitive to formaldehyde, ether, and are destroyed by proteolytic enzymes.

Transmission routes

Scheme of human infection

The source of infection is a sick person, primates and bats. The virus is transmitted by yellow fever mosquitoes of the genus Aedes, mainly Aedes aegypti, but also Aedes albopictus, Aedes scutellaris, Aedes polynesiensis.

Having penetrated the body of a blood-sucking insect with the patient’s blood, the pathogen develops in its intestines at a temperature of at least 22 °C, and after 8-14 days it spreads to other parts of the body. The mosquito becomes infectious by excreting the virus in its saliva throughout its life. Mosquitoes are active and reproduce at a temperature of 28 °C - during this period, the maturation time of the virus is reduced to a minimum.

A person is sensitive to the pathogen, so one insect bite is enough for infection. A person bitten becomes infectious the day before symptoms appear and spreads the infection for 5 days after the onset of the disease.

In countries where mosquito vectors live, endemic foci have formed, and outbreaks of epidemics occur periodically. Major pandemics occur when a new serotype of the virus is introduced into an area. The classic form is observed among the local population (mainly children) and visitors. Hemorrhagic fever primarily affects babies under one year of age who have passive immunity to another type of virus - they develop a primary immune response. This group includes children who have previously had the disease and who develop a secondary type of immune system reaction to the new serotype. The virus is also dangerous for elderly and frail people with asthma and diabetes.

Symptoms

After a mosquito bite, the virus multiplies in the cells of the lymph nodes and endothelium lining the cavity of the blood vessels, destroying them. After 5 days, primary replication ends, and the particles enter the bloodstream - they enter the brain, heart, liver and other organs, causing fever and signs of intoxication.

The virus actively multiplies in monocyte cells and tissue macrophages. As a result, the affected particles produce enzymes that affect inflammatory proteins, change the permeability of the vascular walls and the blood coagulation system. These factors influence the development of the form of the disease and its clinical manifestations.

Classic shape

In the classic course of the disease, from the introduction of infection to the appearance of symptoms of the disease, on average, it takes from 3 days to two weeks, more often - 5-7 days. The short-term prodromal period is characterized by decreased appetite and weakness, conjunctivitis and rhinitis.

Often the disease manifests itself acutely, the following are observed:

• dizziness and intense headache concentrated behind the eyes;
• nausea with vomiting;
• chills and a sharp increase in temperature up to 39°, often up to 41°;
• hyperemia and puffiness of the face, scleral injection, in 80% of patients the next day there is general erythema (redness of the skin caused by dilation of the capillaries);
• enlargement of peripheral lymph nodes;
• severe pain in the vertebral and thigh muscles, in the joints (usually in the knees), sometimes noticeable swelling appears;
• rapid heartbeat (on the 2nd or 3rd day, tachycardia turns into relative bradycardia);
• coated tongue and redness on the palate.

Myalgia and arthralgia cause difficulty in movement, which is expressed in a change in gait - it becomes mannered and unnatural. This symptom formed the basis for the name of the disease: dengue - distorted English word dandy (dandy). A decrease in leukocytes (leukopenia) and platelets (thrombocytopenia) is detected in the patient’s blood, and the presence of protein is detected in the urine.

After 3 or 4 days, a sharp drop in temperature is accompanied by profuse sweating. The person’s well-being improves, but pain in the muscles and joints remains. The next wave of exacerbation provokes a repeated increase in temperature over 2-3 days, but with lower rates, which is associated with the penetration of pathogenic agents into the organs.

During the period of apyrexia (between attacks) or during a new exacerbation (approximately on the 6th - 7th day of the disease), the erythema transforms into a multimorphic profuse rash in the form of urticaria or maculopapular formations, which are accompanied by pityriasis-like peeling.

The duration of the disease is up to 9 days until a sufficient amount of antibodies accumulates in the blood. Full recovery, even with a mild course, occurs after 3-4 weeks, in some cases it lasts up to two months, while signs of weakness, pain in muscles and joints remain.

Hemorrhagic form

Petechial rash

The duration of incubation of the hemorrhagic form is 4-10 days. The disease is manifested by a sharp increase in temperature, signs of intoxication, and cephalgia. Myalgia and arthralgia are often absent. The condition is accompanied by:

• conjunctivitis;
• nausea and vomiting;
• disturbance of consciousness (prostration);
• enlarged liver, abdominal pain;
• the appearance of a petechial rash on the skin after 2 or 3 days - the formation of hemorrhagic purpura and extensive areas of hemorrhage (ecchymosis) is possible.

Mainly small vessels are affected. Deterioration of blood aggregation in severe cases is manifested by bleeding gums and nosebleeds, hemorrhages in the internal organs: Gastrointestinal tract, lungs, myocardium.

Damage is indicated by bloody vomiting, black semi-liquid feces (melena), and blood in the urine (hematuria).

On the 3rd - 7th day, 40% of patients develop shock syndrome. It is believed to be caused by autoimmune processes. The condition is characterized by increased permeability of the vascular walls, which leads to plasma leakage, thickening of the blood and a decrease in protein in it (hypoproteinemia). Due to internal bleeding, the patient's blood pressure drops, tachycardia develops, and intravascular coagulation accelerates with the formation of blood clots. Due to lack of blood, internal organs and the brain suffer, cyanosis, loss of consciousness, and sometimes convulsions are observed.

To determine the severity of disorders in the hemorrhagic course of Dengue fever and determine the prognosis, a classification has been created that divides the disease into stages:

Careful monitoring of patients is important. Urgent medical attention is needed if signs of shock appear: weakening and increased heart rate, cold extremities, blue discoloration around the mouth (cyanosis), decreased blood pressure and a sharp increase in hematocrit. Excessive agitation or lethargy may be evidence of shock.

Complications

The virus is carried by blood into the liver, bone marrow, connective tissues, muscles, subjects them to cytolysis, and also penetrates into nervous system, therefore, it is possible to develop complications after the illness, which manifest themselves:

• otitis;
• thrombophlebitis;
• polyneuritis;
• psychosis;
• encephalitis or meningitis;
• cerebral edema;
• mumps, and in men - orchitis.

In pregnant women, the infection can cause miscarriage or fetal death.

Diagnostics

Making a diagnosis when classic painting The disease is not difficult and is based on the typical manifestations of Dengue fever:

• muscle and joint soreness;
• change in gait;
• two-wave flow;
• exanthema and enlarged lymph nodes.

Errors are possible with an atypical course of infection, when the high temperature remains at the same level and there are no rashes.

In the hemorrhagic form, a preliminary diagnosis is established based on signs of intoxication and identification of hemorrhagic diathesis. During examination, a “tourniquet test” helps confirm the assumption: a positive reaction is noted when, after applying a bandage or pneumatic cuff to measure pressure for 5 minutes, new spots of intradermal hemorrhage appear at the site of exposure. The presence of disease outbreaks, mosquito bites, and visits to endemic areas must be taken into account.

Early laboratory blood tests:

• confirm the presence of the virus in the body using PCR or through intracerebral infection of newborn young white mice;
• show the dynamics of the increase in antibodies to the type of virus introduced and its related species using serological studies of RPHA or RSK, enzyme immunoassay testing;
• detect a decrease in the number of white blood cells and platelet mass, metabolic disorders in the direction of decreasing pH (metabolic acidosis);
• show a moderate increase in the enzyme transaminase in the liver, which is associated with leukopenia and thrombocytopenia.

Severe fever leads to plasma leakage and blood thickening, so examination reveals an increase in hematocrit (red blood cells) and a decrease in albumin concentration (hypoalbuminemia), which indicates movement of exudate from the vascular space. If there is a noticeable accumulation of fluid in the abdominal cavity and pleural effusion, pathology is detected during a physical examination. The beginning of the process is difficult to detect, so ultrasound examination is used.

The classic version of Dengue fever is differentiated from influenza, yellow fever and pappataci fever, and in children - from measles and rubella. Hemorrhagic form - from hemorrhagic diathesis of non-infectious nature and other types of viral invasions, similar in clinical manifestations - chikungunya, Crimean and Omsk, yellow hemorrhagic fever, etc.

Treatment

Polyion solution

Etiotropic therapy for Dengue fever is not carried out, since methods to combat the virus do not yet exist. Measures are being taken to relieve symptoms of the disease:

• For severe joint pain, painkillers are used.
• For insomnia, delirium and agitation, barbiturates, bromides or tranquilizers are prescribed.
• If dehydration develops due to high fever and vomiting, frequent drinking is recommended. A pronounced disturbance of the acid-base balance towards a decrease in pH (acidosis) and an increase in hematocrit (red blood cells) requires infusion therapy: intravenous infusion of glucose, alkaline and electrolyte solutions of sodium chloride and bicarbonate, Hemodesa.
• For severe pain and intoxication, the use of Prednisolone is indicated.
• When a secondary infection occurs, antibiotics are used.

In case of shock, oxygen therapy is indicated - the use of oxygen, cardiac medications. Plasma or its substitutes are injected intravenously until normal body temperature, respiration and pulse are restored. Polyionic solutions are used until the hematocrit level decreases to 40%.

Prognosis and prevention

In sporadic cases of dengue fever, the prognosis is usually favorable. During extensive epidemics, 0.5% of deaths were recorded; during periods of individual outbreaks, mortality reached 2 and even 5%, mainly in childhood. With the hemorrhagic form, about 40% of patients die.

Disease prevention in epidemic areas includes the following measures:

• extermination of mosquitoes and treatment of areas where offspring live;
• the use of fumigators, repellents and nets to block access to the premises;
• wearing long sleeves to protect against bites;
• compliance with sanitary standards and storage of water in closed containers;
• isolation of patients and avoidance of contact with the carrier until the period of illness is over.

It is possible to prevent the spread of infection from endemic areas through quarantine measures.

Currently, the only vaccine against Dengue fever is CYD-TDV, which is based on weakened strains of 4 serotypes of the virus. It is approved for use after 9 years, but its final qualification has not yet been carried out. Research results have shown that the effectiveness of vaccination in treating infection remains at 60-79%. Controversy arises due to cases of severe disease development due to the use of the vaccine in children, therefore, further testing and new developments are required due to the discovery of a new fifth virion.