DENGUE (dengue; the distorted English dandy the dandy) — the acute disease proceeding in two forms — classical fever of a dengue and hemorrhagic fever of a dengue.
Causative agents of classical fever of a dengue and hemorrhagic fever of a dengue — viruses from the Togaviridae family, the sorts Flavivirus of the 1, 2, 3 and 4 antigenic types enter into ecological group arbovirus (see). They are various on an antigenic structure, but cause the diseases similar on a wedge, a picture. Viruses are differentiated on a neutralization test and on credits of RTGA. The people who had the disease caused by one of types of viruses within 2 months of a rezistentna to others.
Viruses D. are sensitive to ether. Collapse dezoksikholaty sodium. Very much termolabilna, remain only in the presence of stabilizers (serum, solution of albumine). At t ° — 70 ° or in the dried-up look they remain up to 8 — 10 years.
Viruses pathogens for newborn white mice at infection in a brain and intraperitoneally. The virus adapted to adult mice loses pathogenicity for the person. Chicken embryos are susceptible. Viruses D. in cultures of tissues of kidneys of monkeys, hamsters, the person, testicles of monkeys, and also the intertwined lines of cells HeLa, KV and skin of the person breed.
Cytopathic activity of viruses D. is expressed poorly and is most regularly shown in cells of VPK-21, HeLa and kidneys of monkeys. Viruses D. of the 2nd and 3rd types have rather bigger cytopathic activity.
Classical fever of a dengue
Classical fever of a dengue (synonym: breakbone fever, joint fever, five-day fever, seven-day fever, fever of «giraffes») proceeds with fever, arthralgias and mialgiya, a dieback, a polyadenitis and a leukopenia.
the Name of a disease is given in 1869. The London Royal college of doctors also comes from the English word «dandy» (dandy) that emphasizes peculiar, changed gait of patients. For the first time observed epidemic of this disease and described it under the name «joint fever» and «remittiruyushchy fever» D. Bylon in Batavia in 1779 and Rush (V. of Rush) in Philadelphia in 1780. In 19 and 20 centuries in various countries with tropical and subtropical climate numerous epidemics were registered.
In 1906 Bankroft (T. L. Bancroft) suggested about transfer of a disease of mosquitoes of Ayodes aegypti. In 1907 Mr. Ashbern (R. M. of Ashburn) and Ch. Craig established the virus nature of a disease. However only in 1944 Mr. Seybin (And. Century of Sabin) allocated and studied a virus D.
=== Geographical distribution === in detail D.'s Diseases were registered between 42 ° sowing. and 40 ° yuzh. latitudes in North, Central and South America, in some countries of Africa, Southern and Southeast Asia, Greece, Spain, on the lake of Cyprus. In the USSR the disease does not meet.
Sources of an infection — the sick person and monkeys at whom the disease can proceed latentno. Circulation of a virus in blood is noted for 6 — 18 hours before emergence a wedge, symptoms and continues within 3 — 5 days from the beginning of a disease. Transfer of the activator happens at a sting the infected mosquitoes carriers of Aedes aegypti, A. albopictus, A. hebridens, A. polynesiensis, And. scutellaris. The virus in a body of a mosquito can develop at a temperature not below 22 °. The mosquito becomes infectious in 8 — 14 days and remains infected for life (from 1 to 5 month).
In the endemic centers the disease is registered in the form of sporadic cases, is preferential among children and visitors. Epid, D.'s flashes are observed in the countries with tropical and subtropical climate at a drift of a virus of that serol, type which was not registered in this area earlier. Incidence has seasonal fluctuations, its growth is usually connected with a rainy season.
Pathogeny diseases it is not studied. The virus is brought by a blood flow in a liver, muscles, marrow, connecting fabric. According to Voykulesku (M. of Woiculesku, 1964), the virus has tropism concerning a nervous system. The cells affected with a virus are exposed to a cytolysis.
Pathological anatomy it is studied insufficiently. At gistol, researches dystrophic changes in a liver, kidneys, a myocardium, a brain are revealed.
After the postponed disease develops type-specific immunity duration up to 2 years. Recurrent diseases during the same season are caused by other type of a virus.
The clinical picture
the Incubation interval of 3 — 15 days, is more often than 5 — 7 days. The disease begins sharply — with a fever and sudden rise in temperature to 39 — 41 °. From the first day of a disease the intensive headache, dizziness, a loss of appetite, nausea, an oxycinesia of eyeglobes is noted. Severe pains in muscles of a back, hips, on the course of a backbone, in joints are characteristic (especially knee). Small joints can swell up a little. Owing to difficulty of movements gait of patients is broken, becomes unnatural, pretentious. The person is hyperemic, odutlovato. Vessels of scleras are injected. Peripheral limf, nodes are increased. Quite often for the 2nd day of a disease the general erythema appears. With 2 — the 3rd day of a disease tachycardia is replaced by relative bradycardia. In a picture of blood a leukopenia till 1500 in 1 ml, thrombocytopenia, relative limfomonotsitoz. High temperature keeps 3 — 4 days, decreasing critically to norm with pouring then. The condition of patients improves, but arthralgias and mialgiya remain. Gait remains unnatural. In 1 — 4 day temperature increases again and 2 — 3 days keep. At the second rise temperature is lower. At this time against the background of fever, and sometimes in an apireksiya after the second wave (6 — the 7th day of a disease) there is plentiful makulopapulezny or urtikarny pruritic rash which is leaving behind a scaly peeling. In 10 — 20% of cases the disease proceeds without rash.
Reconvalescence even at easy disease drags on to 3 — 4, and sometimes 6 — 8 weeks when remain astenisation, muscular and joint pains.
Complications are observed seldom. Thrombophlebitis, encephalitis, meningitis, psychosis, a polyneuritis, pneumonia, parotitis, otitis, an orchitis can take place.
Diagnosis does not present difficulty in the presence of characteristic symptoms of a disease (two-wave fever, the expressed muscular and joint pains, the changed gait, a dieback, a polyadenitis, a leukopenia) taking into account data epidemiol, the anamnesis. Diagnostic mistakes arise at an atypical current of D. when there are no fever or rash, and the temperature curve has one, but long feverish wave.
Laboratory confirmation of the diagnosis is based on allocation of a virus from blood of patients in the first 2 — 3 days of a disease, and also on increase of a caption of specific antibodies in the pair serums taken in the first days and later 2 — 3 weeks in RSK, a neutralization test (PH) and RTGA.
Differential diagnosis classical form of fever of a dengue it is carried out with flebotomny fever (see), at a cut there are no so expressed damages of joints, gait does not change, the injection of scleral vessels at outside corners of eyes in the form of a triangle is always observed. Differs from yellow fever (see) absence of jaundice, and from flu — lack of the catarral phenomena. The catarral phenomena and Filatov's spots — Velsky at measles (see) allow to otdifferentsirovat it from D. Otlichayetsya D. and from rubellas (see) absence of pharyngitis and increase occipital limf, nodes.
there are no Specific remedies. The complex of symptomatic means is applied. For reduction of muscular and joint pains appoint soothing — pyramidon, acetilsalicylic to - that, analginum. At motive excitement, nonsense, sleeplessness bromides, barbiturates, aminazine are recommended. For fight against intoxication, acidosis solution of glucose, isotonic solution of sodium chloride with addition of 4 g of hydrosodium carbonate on 1 l of solution intravenously enter 10%. Use of Prednisolonum shortens duration of a pain syndrome, reduces intoxication. Purpose of a complex of citrins, With, is shown Century. Antibiotics apply at secondary bacterial complications.
Forecast diseases at sporadic cases are more often favorable. During some large epidemics the lethality made ODES — 0,5%, and in separate epidemics increased up to 2 — 5% and was observed generally among children.
the Main means of fight is destruction of places of breeding of mosquitoes and destruction of the inspired mosquitoes. For protection against stings of insects repellents, protecting screens are used. Patients are isolated to rooms where access of carriers for the period of the infectious period is excluded. The prevention of a drift of an infection from the endemic countries is carried out by means of quarantine actions. Offered by Seybin and Schlesinger (A. V. of Sabin, R. W. Schlesinger, 1945) the live vaccine was ineffective.
Hemorrhagic fever of a dengue
Hemorrhagic fever of a dengue proceeds with the expressed hemorrhagic syndrome, affecting preferential children.
For the first time D. with a hemorrhagic syndrome is registered in 1954 in Manila. In the next years epid, the outbreaks of hemorrhagic fever of a dengue were noted in a number of the countries of Southeast Asia and in the region South zap. parts of the Pacific Ocean. Big epidemics were in Rangoon, Bangkok and Manila.
Diseases are registered hl. obr. in the countries of Southeast Asia. Epid, flashes are observed in city settlements on the Philippine islands, in Thailand, Burma, Kampuchea, Laos, Indonesia, Malaysia, Singapore, and also in India.
the Source of an infection — the person and probably monkeys. Transfer of the activator happens through a sting of a mosquito of Aedes aegypti, A. albopictus, And. scutellaris, etc. from which virus was allocated during epidemic. There are no proofs of a possibility of direct transfer of a contagium from the person to the person. Diseases are noted usually only during rainy seasons in areas with a high number of mosquitoes carriers. The age of the patients with hemorrhagic fever of a dengue in many areas (except Singapore and Calcutta) fluctuates from 4 months to 30 years (more often 3 — 5 years). Antiserum capacities to a virus D. at more senior children and adults are usually higher, than at children of younger age. Many mild cases of D. are distinguished only with the help serol, reactions. Hemorrhagic fever of a dengue does not affect Europeans though they got sick with classical fever of a dengue during epidemics. It indicates communication of diseases of hemorrhagic fever of a dengue with some changing factors of a susceptibility of an organism of the owner.
In pathogeny hemorrhagic fever of a dengue as it is considered to be, the sensitization of the human body which transferred a slight disease of D. in the past, and then several months later or years undergone the second attack of viruses D has exclusive value. Against the background of the perverted reactivity of an organism heavy shock and a hemorrhagic syndrome develops.
Owing to damage of cells and a hyperpermeability of capillaries the hypovolemia develops (see. Oligemiya ). The mass of the circulating blood sharply decreases to a critical level. Comes acidosis (see), an anoxia (see. Hypoxia ), hyperpotassemia (see).
On openings find the selective defeat of small vessels which is shown multiple hemorrhages in endo-and a pericardium, c. N of page, muscles, skin and mucous membranes.
A clinical picture
the Incubation interval — 4 — 10 days. The disease begins usually suddenly with high temperature, a headache, nausea, vomiting; the patient is in a condition of prostration. There are abdominal pains, conjunctivitis, the phenomena of hemorrhagic diathesis: nasal, pulmonary, went. - kish. bleeding, petekhialny hemorrhagic rash; sometimes phenomena of a hemorrhagic purpura, extensive ecchymomas. Approximately at 40% of patients on 3 — the 7th day of a disease arises the heavy shock caused, apparently, by autoimmune processes. Shock is followed by sharp increase in the vascular permeability leading to leak of plasma, a pachemia, a hypoproteinemia.
Hemorrhages in went. - kish. the path or lungs can imperceptibly occur. It is considered that in a wedge, a picture of the disease arising in the different countries there are distinctions: increase in a liver was noted at patients in Thailand and was absent at patients on Philippines, but to their thicket nasal bleedings were noted. In blood the leukopenia, thrombocytopenia, lengthening of a blood clotting time is noted. In urine of squirrels, sometimes blood.
Diagnosis is based on the expressed symptoms of intoxication, the phenomena of hemorrhagic diathesis taking into account data epidemiol, the anamnesis and is confirmed serological or allocation of a virus.
In serol, reactions raising of antiserum capacities to the corresponding types of a virus which caused a disease and to related viruses is usually noted. The activator can be allocated from blood of the patient in the first 2 days of fever by intracerebral infection of white mice suckers.
Differential diagnosis hemorrhagic form of fever of a dengue it is carried out with noninfectious hemorrhagic diathesis of which gradual development, lack of symptoms of intoxication is characteristic, and with hemorrhagic fevers (see) which on a wedge, a picture to distinguish very difficult. In these cases the diagnosis is established on the basis epidemiol, data, serol. by method and allocation of a virus.
Treatment it is directed first of all to fight against shock, intoxication, acidosis, a collapse. Intravenously enter solutions of glucose (5%), a reopoliglyukin, isotonic solution of sodium chloride, 4% solution of hydrosodium carbonate, Haemodesum. At a hypoproteinemia — plasma transfusion, Polyglucinum, Amincrovinum, Aminopeptidum, cardiovascular means, corticosteroid drugs are shown.
Forecast in hard cases it is serious. The lethality apprx. 5%, among children is younger than 15 years — to 10 — 15%.
Prevention — fight against carriers by the same methods, as at classical fever of a dengue.
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