Tularemia, Batai fever and 6 other diseases carried by mosquitoes, ticks and flies

Mosquitoes and flies in Russia can carry dangerous diseases. Cases of infection transmission are recorded infrequently, but nevertheless we should not forget that you can get infected from bloodsucking insects not only in foreign countries.

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What diseases can be transmitted through mosquito bites?

On the territory of Russia there are more than 100 species and subspecies of mosquitoes. To endemic (that is, characteristic of the area) for our country, infections transmitted by these bloodsucking insects include:

1. Tularemia.
2. Dirofilariasis.
3. West Nile fever.
4. Fevers caused by viruses of the California encephalitis group (Inco, Tyaginya, Khatanga fever).
5. Batai fever.
6. Sindbis fever.
7. Karelian fever.
8. Semliki Forest fever.

There are also infections transmitted by mosquitoes that are not endemic to Russia. Among them are malaria, yellow fever, Dengue, Zika and Chikungunya fevers. As a rule, such infections are “imported”, i.e. they are brought into the country by people who contracted them in endemic areas.

Some mosquito species found on the Black Sea coast of the Caucasus and in the south of Krasnodar Krai may be potential carriers of pathogens of these non-endemic infections.

Let us tell you about the most known diseases.

Tularemia

doctor-epidemiologist of the Federal network of clinics of expert oncology “Euroonco”

“Tularemia is widespread throughout the country, covering almost all regions of Russia”….

The disease is caused by the bacterium Francisella tularensis, which is characterized by high infectivity. Its natural foci occur in different climatic zones and are linked to a variety of landscapes: meadows, steppes, fields, swamp floodplains, foothills and mountain streams, forests and tundra.

To date, tularemia is registered both sporadically (from case to case) and in the form of epidemic outbreaks of varying intensity. In recent years, the number of cases has ranged from 100 to 400 people per year, with more than 75% of cases occurring in three federal districts: Northern, Central and West Siberian.

The main source of infection is mammals, primarily rodents, rabbits and hares. Infection can also occur through bites of blood-sucking insects (ticks, mosquitoes, gadflies), consumption of contaminated food or inhalation of aerosol from grain and hay processing containing the pathogen from diseased rodents.

The incubation period of the infection – from infection to the appearance of symptoms – is on average 3-7 days (maximum 21 days).

The initial stage of the disease is characterized by:

• acute onset with chills and a rise in body temperature to 38-40 degrees and above;
• weakness, headache, dizziness;
• decreased appetite;
• decreased blood pressure;
• various muscle pains (especially in the lower back and calves);
• sleep disturbance;
• increased sweating, especially at night.

In severe cases, there may also be intense headache, conjunctivitis, bluish-blue complexion, nosebleeds, skin rash, and enlargement of the liver and spleen.

The duration of the disease averages 16-30 days. If the lymphatic system is affected, the disease can drag on for up to 2-3 months.

The probability of fatal outcome in the absence of treatment is 5-15%, with treatment – 1-3%.

Dirofilariasis

This is an infectious disease caused by parasitic worms of the genus Dirofilaria. Most often they are transmitted to humans through the bites of infected mosquitoes.

On the territory of Russia, dirofilariasis is found in the southern regions: Krasnodar Krai, Volgograd, Rostov, Astrakhan regions, and in Crimea. Single cases of the disease have been registered in the Moscow, Ryazan, Tula Regions, in the Urals and Siberia.

The incubation period after infection may last up to 30 days or may drag on for a couple of years.

Symptoms of dirofilariosis depend on the form of course.

So, in the cutaneous form, when the parasite is under the skin, the following signs are manifested:

• compaction under the skin and painful sensations when palpating it;
• a feeling of moving and crawling parasite under the skin;
• reddening of the skin over the seal.

The ocular form of the disease is also common, when the worm settles under the skin of the eyelids, in some cases – under the conjunctiva of the eyes or even in the eyeball itself. In this case, signs similar to symptoms of allergic reaction, conjunctivitis or other eye diseases may be observed:

• a feeling of sand, a foreign body in the eye;
• swelling and redness of the eyelids;
• itching;
• soreness with eye movement;
• lacrimation.

Any form of dirofilariosis may also present with general complaints, including weakness, restlessness, sleep disturbances, irritability, and headaches.

Cases of dyrofilariae infecting the lungs and heart in humans are extremely rare.

West Nile fever

The area of spread of the virus is quite wide: Astrakhan, Volgograd, Rostov regions, Krasnodar Krai, as well as the southern regions of Siberia and the Far East.

The infectious disease is transmitted to humans from infected mosquitoes, less often from ticks. From the moment of infection to the manifestation of signs of the disease can take from 2 to 14 days, on average, the incubation period is 3-6 days.

Symptoms of West Nile fever can be confused with a cold or flu:

• A rapid rise in body temperature to 38-40 deg;
• chills;
• sore throat;
• headaches.

There may also be signs of intestinal distress: abdominal pain and frequent stools.

What can flies infect?

Another vector of infections are flies. They can spread tularemia, tuberculosis, anthrax, brucellosis and other diseases.

Intestinal infections

These insects carry dangerous pathogens such as salmonella or E. coli.

Infection does not occur through a bite. Therefore, experts do not recommend leaving food in a place accessible to flies.

Intestinal infection is indicated by the following symptoms:

• висока телесна температура;
• weakness;
• pain in the head, muscles, abdomen;
• nausea;
• vomiting;
• diarrhea.

Tuberculosis

Flies can actually infect humans with this dangerous disease. Flying from place to place, the insects transfer bacteria from the excretions of the patient to food. The tubercle bacillus feels perfectly well outside the human body, especially in damp, dusty, dark and poorly ventilated rooms.

The main source of infection is the sputum secreted by a TB patient.

The disease can be recognized by the following symptoms:

• elevated body temperature;
• cough for more than two weeks;
• heavy sweating at night;
• chest pains;
• hemoptysis;
• shortness of breath;
• unexplained weight loss;
• fatigue.

What infections can be contracted through tick bites?

Many people know that these bloodsuckers can infect humans with tick-borne encephalitis and Lyme disease (these are the infections of choice), but not everyone has heard that ticks also carry tularemia, ehrlichiosis, tick-borne relapsing typhus, granulocytic anaplasmosis, babesiosis, and spotted fever.

Tick-borne encephalitis

The virus is transmitted by tick bite. Almost 50 regions of Russia are endemic for tick-borne encephalitis – the list of territories is approved annually by the Russian Federal Service for Supervision of Consumer Rights Protection and Human Welfare.

The disease affects the brain and spinal cord. As a rule, from infection to the appearance of the first signs of the disease takes from one to 30 days: 7-12 on average.

Symptoms of tick-borne encephalitis:

• general malaise;
• weakness in the muscles of the limbs and neck;
• increased body temperature;
• headache;
• insomnia;
• nausea and vomiting;
• confusion;
• redness of the face, neck.

Tick-borreliosis, or Lyme disease

This is a serious disease that is especially dangerous for the elderly. Infection can lead to arthritis, cognitive impairment, peripheral nerve paralysis, hearing and vision loss, and other complications.

Lyme disease is also dangerous in that it is much more common than tick-borne encephalitis, acquiring a chronic course.

From the moment of infection to the first symptoms usually takes from three to 30 days. Symptoms of the disease include:

• erythema migrans around the bite site (ring-shaped redness);
• fever;
• headache;
• fatigue;
• stiffness in the neck muscles;
• nausea and vomiting.

Anaplasmosis

In human granulocytic anaplasmosis, the pathogen penetrates the white blood cells, leukocytes, causing inflammation throughout the body. The incubation period of the infection ranges from three to 23 days: on average 14 days.

Symptoms of anaplasmosis:

• fever;
• weakness;
• chills;
• headache, joint and muscle pain;
• nausea and vomiting;
• upset stools;
• coughing, sore throat and stuffy nose may occur.

How can I protect myself from bloodsucker infections?

As we have already realized, the bites of bloodsucking insects are not only unpleasant and painful, but also dangerous to health. Although the risk of contracting serious infections is low, it is still there.

To minimize the risk of infection, you can use smoke spirals and repellents in nature. At home, mosquito nets and fumigators can help you protect yourself from mosquitoes. If you live outside the city, experts recommend treating the area with special chemical preparations.