Mosquito Fever (Pappatachi Fever)

What is mosquito fever (pappatachi fever)?

Pappatachi fever (synonyms: mosquito fever, three-day fever, phlebotomus – fever, soldier’s disease) is an acute arbovirus disease, characterized by short-term fever, severe headache, myalgia, conjunctivitis and peculiarly injectables and specific injectables and specific injectables.

What triggers mosquito fever (Pappatachi fever)?

The causative agent of fever pappatachi belongs to the bunyavirus (Vipuaviridae family, Phlebovirus genus). It has now been established that at least 5 immunologically distinct phleboviruses can cause this disease, in particular, the causative agents of Neapolitan mosquito fever, Sicilian mosquito fever, Punta Toro, Chagres and Candira. There may be other variants of the pathogen. They are characterized by common properties. The size of the virus particles 40-50 nm, inactivated when heated, under the influence of disinfectants. Cultivated on chicken embryos, newborn mice, tissue cultures. Formalin (1: 1000) inactivates the virus without depriving it of its immunogenic properties. The vaccine can also be made from strains of the virus adapted to chicken embryos or mice.

The main host of the virus is man.

The reservoir and carrier of infection are mosquitoes (Phlebotomus rarratasif, perhaps also Ph. Caucasicus, Ph. Sergenti). Mosquitoes become infected by the bites of a sick person, the virus in mosquitoes can be transmitted transovarially. They assume that birds can be an additional reservoir of infection. Mosquitoes are very small, able to penetrate the premises through small cracks, their bite does not cause irritation and is often not noticed. Only about 1% of the patients noticed mosquito bites. The disease is spread throughout the Mediterranean basin, in the Balkans, the Middle East, in eastern Africa, in Pakistan, in certain regions of India, China and other Asian countries. Pappatachi fever is also found in Panama and Brazil. The incidence is characterized by seasonality, has two seasonal increases – in May-June and at the end of July-August, which are due to the seasonality of the number of mosquitoes-carriers. Mass diseases are observed, as a rule, in persons who arrived for the first time in endemic areas. The local population suffers the disease in early childhood, which leads to the development of immunity, which is then maintained at a high level.

Pathogenesis during mosquito fever (Pappatachi fever)

The pathogen penetrates through the skin or mucous membranes, at the site of introduction the primary affect is not observed, and there is no increase in regional lymph nodes. Reproduction and accumulation of the virus in the human body occurs quickly. In the first 2 days of the disease, the virus is detected in the patient’s blood. The main changes in fever papatachi occur in small blood vessels, striated muscles and in the nervous system.

Symptoms of Mosquito Fever (Pappatachi Fever)

The duration of the incubation period ranges from 3 to 9 days (more than 4-5 days). The disease, as a rule, begins suddenly, the body temperature rises with chills and in a few hours reaches 39-40 ° С, in some cases 4 ° C. Patients complain of severe headache in the forehead, pain during eye movement and retroorbital, photophobia, general weakness, pain in the calf mice, sacrum, back. Sometimes there are muscle pains in the chest and abdomen, resembling those with epidemic myalgia.

The following symptoms are characteristic – severe pain when lifting with the fingers of the upper eyelid (the first symptom of Taussig), soreness with pressure on the eyeball (the second symptom of Taussig), pronounced hyperemia of the sclera conjunctiva in the shape of a triangle, pointing apex to the cornea. The triangle is located at the outer corner of the eye (Pick’s symptom). The sharp hyperemia of the skin of the face, vascular injection of the sclera, hyperemia of the mucous membrane of the pharynx, swelling of the palatine arches and uvula attracts attention. In the soft palate, an enanthema may appear in the form of small bubbles, a herpetic rash on the lips, in some patients maculae elements appear on the skin, sometimes merging into erythematous fields, urticarial elements. Bradycardia is noted at the height of fever, BP is lowered. Signs of catarrh of the upper respiratory tract are absent or weakly expressed. An enlarged spleen is rare. Some patients develop abdominal distention and loose stools 5-6 times a day.

In most patients, the fever lasts 3 days, only in 10% of patients it exceeds 4 days. During the recovery period, the patients noted weakness, decreased physical and mental performance, and headache. In 15% of patients after 2-12 weeks develops a second attack of the disease.

With more severe course (approximately 12% of patients), serous meningitis develops. There is a severe headache, vomiting, stiff neck muscles, the symptoms of Kernig, Brudzinsky. In the analysis of cerebrospinal fluid, moderate cytosis and elevated protein levels are detected. Mild swelling of the optic nerve may also be observed.

Changes in the blood are characterized by leukopenia (2.5-4.0 x 109 / l). Leukopenia sometimes appears only at the end of the febrile period. Lymphopenia, aneosinophilia, monocytosis, leukocyte shift to the left are also characteristic.

Complications: pneumonia, infectious psychosis. Rarely observed.

Diagnosis of Mosquito Fever (Pappatachi Fever)

In diagnosis, one should take into account the geographical location of the locality, the mass of the disease, short duration of fever, and characteristic clinical symptoms (Taussiga, Pika). Of the laboratory methods, the most simple and informative is the study of blood (increasing leukopenia). Specific laboratory methods are rarely used in practice. The increase in the titers of specific antibodies can be identified using the neutralization reaction, RAC, rtga. Examine paired serum taken in the first 2-3 days of illness and after 2-3 weeks.

Differentiate from influenza, leptospirosis, dengue, etc.

Treatment of Mosquito Fever (Pappatachi Fever)

There is no specific treatment, antibiotics and chemotherapy are ineffective. Recommend bed rest at the time of fever, a sufficient amount of fluids, vitamins. Symptomatic therapy is used.

The prognosis is favorable.

Prevention of Mosquito Fever (Pappatachi Fever)

Surrounded by the patient are necessary: ​​the destruction of mosquitoes, protection from their bites (screening windows, use of repellents, etc.). For specific prophylaxis, an embryonic formalin vaccine or a dry vaccine from strains of the virus adapted to chicken embryos is used. The vaccine is administered through scarified skin (like ospreepvial) 2 months before the start of the epidemic season.

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