Crimean Congo hemorrhagic fever virus. Hemorrhagic fever of the Congo-Crimea

Among experts, you can hear other names for this dangerous disease - infectious capillary toxicosis, Crimean-Congo hemorrhagic fever or Central Asian hemorrhagic fever.

The disease got its name after, in 1945, after a detailed study of the blood of sick settlers and soldiers employed in hayfields in the Crimea, its pathogen was identified. After 11 years, cases of a similar disease were recorded in the Congo. Laboratory tests showed that their pathogens are identical.

Susceptibility to the disease is high regardless of the age of the person. Crimean hemorrhagic fever is more often detected in men aged 20 to 60 years. Seasonal outbreaks of the disease are recorded in the summer. Predisposition to the disease are people whose professional activities are related to animal husbandry, as well as hunters and people caring for patients with this infection.

REASONS FOR THE DEVELOPMENT OF THE DISEASE

The causative agent of Crimean hemorrhagic fever is an arbovirus belonging to the Buniavirus family. Its ability to replicate in two temperature ranges (22-25°C and 36-38°C) allows the pathogen to multiply both in the body of insects and in the body of humans and warm-blooded animals.

The virus of the Crimean hemorrhagic fever is inactivated by solutions of disinfectants and fat solvents. During boiling, it quickly dies, heating to 45 ° C leads to its death within two hours, while freezing the virus persists for a long time.

The development of Crimean hemorrhagic fever is poorly understood. Gates for the penetration of an infectious agent are the site of a tick bite or skin lesions, as well as direct contact with infected blood. At the site of penetration of the virus tissue is not changed.

SYMPTOMS

The incubation period of the Crimean hemorrhagic fever is relatively short, usually a latent course is observed for 3-7 days, but the duration of the latent period can vary between 1-14 days. So, with a tick bite, it lasts up to three days, and with a contact route of transmission, it lasts about 5-9 days.

The pathological process manifests rapidly. The first symptoms of the Crimean hemorrhagic fever make themselves felt by an increase in temperature to critically high levels, which is accompanied by intoxication.

Signs of the first stage of the Crimean hemorrhagic fever:

  • increase in body temperature;
  • chills;
  • nausea, vomiting;
  • slow heart rate (bradycardia);
  • weakness;
  • migraine;
  • myalgia and arthralgia;
  • fear of bright light;
  • pain in the epigastrium;
  • redness of the face and mucous membranes.

Before the manifestation of the disease, the body temperature drops to 37 ° C, and then rises again. On the 3-6th day after the onset of the disease, the condition worsens significantly, the next stage of the disease develops - hemorrhagic syndrome.

Signs of the hemorrhagic stage:

  • bruising on the skin and mucous membranes, resembling bruises, rashes or spots;
  • bleeding at the puncture sites with a syringe;
  • nosebleeds;
  • bleeding gums;
  • pain in the liver;
  • yellowing of the skin;
  • hepatomegaly;
  • vomiting and diarrhea;
  • enlarged lymph nodes;
  • pallor and swelling of the face;
  • tachycardia.

The fever continues for 10-12 days. The cessation of bleeding and the stabilization of body temperature to normal levels indicate the transition to the recovery stage. As a rule, after the transferred Crimean fever, patients are in an exhausted state for another 1-2 months.

The outcome of the disease depends on the severity of the symptoms. Hemorrhagic manifestations of the Crimean hemorrhagic fever can have a different severity - from skin rashes to abdominal bleeding from the digestive, respiratory and internal genital organs (uterine bleeding).

At this stage of the Crimean fever, severe conditions can develop, which are accompanied by convulsive phenomena, confusion and coma.

Complications of the Crimean hemorrhagic fever:

  • sepsis;
  • pulmonary edema;
  • otitis;
  • secondary bacterial infections;
  • focal type pneumonia;
  • impaired renal function;
  • thrombophlebitis;
  • infectious toxic shock.

At autopsy of patients who died from this infection, multiple bruises are found on the mucous surface of the digestive tract, in the lungs, kidneys, liver, hyperemia of the brain, its membranes and hemorrhages with damage to the medulla.

Sometimes hemorrhagic syndrome and re-growth of body temperature are absent. Often, with such symptoms, Crimean hemorrhagic fever is not detected, since signs of intoxication have common features with other common infections.

TREATMENT

If Crimean hemorrhagic fever is detected, a sick person is urgently hospitalized in an infectious diseases hospital. Such patients are isolated in special boxes to prevent contact with others. They are recommended bed rest and the rejection of physical activity.

The complexity of early diagnosis is that during the incubation period of fever, there are no prodromal phenomena.

Principles of therapy for Crimean fever:

  • Symptomatic treatment with antipyretics based on ibuprofen and paracetamol. With a significant increase in body temperature to critical levels, an intravenous infusion of more effective drugs is performed.
  • Infusion injections for the correction of water and electrolyte balance and the elimination of toxins.
  • Hemostatic agents to prevent or stop bleeding.
  • Antiviral drugs as etiological treatment.
  • Immunocorrective therapy involves the introduction of heterogeneous specific serum obtained from the blood of sick or vaccinated people. In addition, such preparations based on immunoglobulins are used as a prophylaxis in the circle of close contacts.
  • Hyposensitizing therapy.
  • The diet provides for the use of easily digestible food, preference is given to such simple dishes as soups and cereals.
  • Broad-spectrum antibiotics, anti-shock and cardiovascular drugs are prescribed according to indications.
  • Transfusion of donor blood elements to restore normal blood clotting of the patient.
  • Intensive care and resuscitation in extremely severe disease development.

In the treatment of Crimean hemorrhagic fever, the use of drugs based on sulfonamides, which can have a traumatic effect on the kidneys, is excluded.

PREVENTION

After treatment of hemorrhagic fever, immunity to the pathogen persists for 1-2 years. To create sustainable artificial immunity, it is recommended to administer a vaccine made from the brains of infected rats and mice. Preventive vaccination is recommended for everyone who plans to travel to the southern regions of Russia and Ukraine.

For the prevention of Crimean fever, tick control is carried out.

Primary prevention measures:

  • regular disinfection of livestock buildings with special chemicals against ticks - acaricides;
  • a ban on grazing animals in natural foci of the spread of the disease;
  • treatment of animals with pesticides and quarantine before being sent to the slaughterhouse;
  • the use of protective equipment in the form of closed clothing and repellents when visiting forests or pastures;
  • regular self-examination to identify stuck ticks.

The destruction of ticks in their natural habitat does not show high efficiency.

For the prevention of Crimean hemorrhagic fever, patients are sent to an isolated hospital. In such patients, according to a special technique, blood is taken, their secretions are disposed of, and instruments are disinfected.

Outbreaks of disease in recent years are explained by non-compliance with anti-epidemic measures and the lack of proper treatment of livestock from ticks that carry the disease.

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Crimean-Congo hemorrhagic fever (CCHF) is a disease that is common on three continents - in Europe, Asia and Africa - and causes a high proportion of deaths, varying from 10 to 50% in different years, and in some cases, when the infectious agent is transmitted from person to person, reaching 80%.

Story

CCHF has been recorded by different researchers and under different names for a very long time: as far back as the 12th century, in the book of the Persian physician Ibu Ibrahim Jurjani, a disease associated with insect bites was described, with clinical manifestations similar to those of CCHF. Subsequently, this disease was designated as Central Asian hemorrhagic fever, karakhalak, infectious capillarotoxicosis, etc. The causative agent of this disease was discovered in 1945 by the Soviet scientist M.P. Chumakov and colleagues and designated as Crimean hemorrhagic fever. However, only in 1970, after the discovery of Congo fever and obtaining evidence of the identity of the pathogens that cause Crimean hemorrhagic fever and Congo fever, scientists involved in this infection came to a consensus on the name of the causative agent of hemorrhagic fever. Since then, it has been called the Crimean-Congo hemorrhagic fever virus.

Epidemiology

Among tick-borne viruses that cause disease in humans, CCHF virus has the highest geographical distribution. Ticks of 30 species are carriers and keepers of the virus, among which ticks of the genus Hyalomma are of particular importance. Ticks of this genus are distributed almost everywhere, but Hyalomma marginatum, Hyalomma asiaticum, and Hyalomma anatolicum have a special role in the distribution of CCHF. These ticks have different biological characteristics, different geographic distribution, but, nevertheless, they are the main sources of infection. Infestation of ticks of this genus with CCHF virus ranges from 1.5 to 20%.

The species composition of animals that carry the CCHF virus with ticks is extensive and includes mammals of various species, birds and, in rare cases, reptiles. Of particular importance in the maintenance of the CCHF virus in nature are animals that have a high level of the virus in the blood, and which provide the spread of the infection, in the so-called "horizontal way". There is also a “vertical” mode of spread, in which the virus is transmitted transovarially (i.e. through tick eggs) and then to larvae, nymphs and adults (adults).

The mechanisms and methods of transmission of the CCHF virus are different: these are the ways of spreading within the outbreak and to the areas bordering it due to tick host animals, and the transfer of immature phases of ticks (larvae, nymphs) by migratory birds for thousands of kilometers.

The bite of an infected tick on a human usually leads to the development of CCHF disease, although cases of asymptomatic infection are sometimes found.

Activation of CCHF

After "silence" that lasted for decades, CCHF in 1999 on the territory of the Russian Federation dozens of cases of this disease were registered.

The reasons for this could be both a reduction in the number of arable land and a decrease in the anti-tick treatment of agricultural and domestic animals. According to Rospotrebnadzor in the Russian Federation, epidemic manifestations of CCHF for the period from 1999 to 2006 were registered in 7 out of 13 subjects of the Southern Federal District of Russia (Rostov, Volgograd, Astrakhan Region, Stavropol Territory, the Republic of Dagestan, Kalmykia, Ingushetia). Over eight years, 766 people fell ill with CCHF, of which 45 (5.9%) died. A tense epidemiological situation was noted in the Stavropol Territory, where 283 patients were detected over the indicated years, which is 39.4% of all patients registered in the Southern Federal District, in the Republic of Kalmykia - 22.1% of patients and in the Rostov Region - 16, nine%.

However, the activation of CCHF has occurred all over the world and the reasons for this are not yet clear. New CCHF foci have appeared in Turkey and Greece, where this disease has never been registered before, a case of importing CCHF to France with this infection has been noted. The ability of the CCHF virus to be transmitted from person to person, unprecedented by previous standards, has been registered: for example, in Mauritania, 19 people were infected from one sick person.

That. it is obvious that the epidemiological features of this infection are undergoing changes, which, according to researchers, is associated with a general warming of the climate. Therefore, it is difficult to predict where else this dangerous infection will spread from the usual areas.

Pathogenesis and clinic of CCHF disease

CCHF refers to natural focal and is characterized by the presence of hemorrhagic syndrome against the background of fever and general intoxication.

The main way the virus enters the body is through the bites of infected ticks and contact with the secretions of patients. It is not uncommon for people to get sick when cutting the carcasses of infected animals and when cutting the hair of “ticked” animals. At the site of a tick bite, as a rule, no changes in the skin are observed. The virus enters the bloodstream and accumulates in the cells of the reticuloendothelial system. During the period of accumulation of the virus, an infected person feels healthy. The incubation period varies from one day after a tick bite to two weeks, and, apparently, depends on the dose of the virus introduced into the human body. The disease begins suddenly and with a sharp rise in temperature (39-40 degrees Celsius). In the prehemorrhagic period (from 1 to 7 days), the phenomena of general intoxication of the body are noted. A constant symptom is fever, which has a “double-humped” temperature curve characteristic of CCHF (during the hemorrhagic period, the temperature drops to subfebrile, and then rises again). The hemorrhagic period is characterized by the appearance of a rash on the skin and mucous membranes and hemorrhages of various localization. The outcome of the disease depends on the severity of the hemorrhagic syndrome. With the normalization of temperature and the cessation of bleeding, recovery occurs.

Genetic studies of the CCHF virus

Despite the fact that the CCHF virus was first discovered by Soviet scientists in 1945, the genetic features of this virus circulating in the Southern Federal District of the Russian Federation and the Central Asian republics remained unknown until 2000.

In 2000, SSC VB "Vector", Institute of Virology named after. DI. Ivanovsky, together with colleagues from Kazakhstan and Tajikistan, began to study the genotypes of the virus circulating in a vast territory, including both the south of the European part of Russia and the territories of Kazakhstan, Tajikistan, Uzbekistan and Turkmenistan. The study was conducted using clinical and field samples obtained during outbreaks of CCHF that occurred immediately during the study period, and collection (historical) strains of the virus obtained at different time periods.

It was found that a genetically homogeneous CCHF virus is circulating in Russia, which differs significantly from the genotypes of this virus from other regions of the world. The homogeneity of this group has been proven using various methods of phylogenetic analysis. A study was made of strains and isolates of the CCHF virus isolated both from patients and from ticks in the Astrakhan, Volgograd, Rostov regions and in the Stavropol Territory. All variants of the virus turned out to be very similar genetically, although there was a tendency to divide this genetic group into two subgroups according to a geographical basis: Stavropol-Astrakhan and Rostov-Volgograd. The strain of the CCHF virus from Bulgaria that we studied was assigned to the same genetic group. These data were later confirmed by other researchers.

A different picture of the distribution of genotypes was found in the study of the CCHF virus circulating in the Central Asian republics. We were able to show that not only "Asian" genovariants of the CCHF virus are circulating in Kazakhstan, but also a virus with a genotype characteristic of South Africa. These data, for the first time, directly confirmed the thesis about the possibility of transferring the CCHF virus from continent to continent. The population of CCHF viruses in other countries of Central Asia also turned out to be heterogeneous: two distinct large genetic groups of the virus were identified, which, in turn, are divided into two subgroups, including previously known genetic variants of the virus from China, Turkmenistan, and Pakistan. Thus, a large degree of heterogeneity of CCHF virus circulating in the Asian region has been established.

The data obtained during these studies made it possible not only to identify genovariants of the CCHF virus circulating in various regions of the CIS countries, to show the possibility of the virus going far beyond its natural range and to create the basis for the development of diagnostic test systems, but also for the first time made it possible to propose a geographical clustering of genotypes CCHF virus.

The tasks that require further research are the study of the possibility of spreading CCHF beyond the usual foci of this infection associated with climate change, as well as the development of a universal vaccine that could be used to prevent CCHF disease in humans and farm animals.

Employees of the FGUN SSC VB "Vector" V.S. Petrov (head of work), O.I. Vyshemirsky, G.I. Tyunnikov, L.N. Yashina, S.V. Seregin , S.S. Seregin, V.V. Gutorov, I.D. Petrova, N.V. Yakimenko, N.N. Tuchina.

Collaborating organizations made an important contribution to the work.

Thanks to colleagues from collaborating organizations:

  • Institute of Virology. D.I. Ivanovsky:
    • Lvov Dmitry Konstantinovich, Director of the Institute, Academician of the Russian Academy of Medical Sciences,
    • Samokhvalov Evgeny Ivanovich,
    • Aristova Valeria Anatolyevna;
  • Kazakh Republican Sanitary and Epidemiological Station, Almaty, Kazakhstan:
    • Ospanov Kenes Sarsengalievich, chief physician,
    • Kazakov Stanislav Vladimirovich,
  • Tajik Research Institute of Preventive Medicine of the Ministry of Health of Tajikistan:
    • Tishkova Farida Khamatgalievna, Director.

Vladimir Semyonovich Petrov
Head of the laboratory of bunyaviruses, Ph.D.
FGUN SSC VB "Vector"

Crimean hemorrhagic fever has an incubation period of 2-14 days (3-5 on average).

There are three clinical forms of the disease:

  • Crimean hemorrhagic fever with hemorrhagic syndrome;
  • Crimean hemorrhagic fever without hemorrhagic syndrome;
  • inapparent form.

Crimean hemorrhagic fever without hemorrhagic syndrome can occur in mild and moderate forms; with hemorrhagic syndrome - in mild, moderate and severe forms. The course of the disease is cyclic and includes the following periods:

  • initial period (pre-hemorrhagic);
  • peak period (hemorrhagic manifestations);
  • period of convalescence and long-term consequences (residual).

The initial period lasts 3-4 days; there are such symptoms of Crimean hemorrhagic fever as: a sudden rise in temperature, severe headache, aches and pains throughout the body (especially in the lower back), severe weakness, lack of appetite, nausea, and vomiting not associated with eating; in severe cases - dizziness and impaired consciousness. Hypotension and bradycardia are also detected.

During the peak period (2-4 days of the course of the disease), a short-term decrease in body temperature is detected (within 24-36 hours), and then it rises again and on the 6-7th day begins to lytically decrease ("double-humped" temperature curve) ; hemorrhagic syndrome develops in the form of a petechial rash on the lateral surfaces of the chest and abdomen, hemorrhages at injection sites, hematomas, bleeding gums, bloody discharge from the eyes and ears, as well as nasal, pulmonary, gastrointestinal and uterine bleeding. The patient's condition deteriorates sharply: symptoms of intoxication, muffled heart tones, arterial hypotension, bradycardia is replaced by tachycardia, the liver is enlarged. They reveal lethargy, adynamia, sometimes stupor and confusion, less often - agitation, hallucinations, delirium. Meningeal symptoms (stiff neck, Kernig's symptom) are often expressed, transient anisocoria, pyramidal signs, convergence disorder are detected. Patients have a characteristic appearance: pharynx, face, neck and upper chest are hyperemic; sclera injected; enanthema is expressed on the soft palate and oral mucosa; jaundice rarely occurs. The severity and outcome of the disease are determined by the severity of the hemorrhagic syndrome. Jaundice in combination with other manifestations of liver damage is a poor prognostic symptom of Crimean hemorrhagic fever. The dominance of hepatitis in the clinical picture can lead to death.

The period of convalescence is long (from 1-2 months to 1-2 years or more); begins with the normalization of body temperature, the cessation of manifestations of hemorrhagic syndrome. This period is characterized by the following symptoms of the Crimean hemorrhagic fever: asthenovegetative disorders: weakness, fatigue, dizziness, headaches and pain in the heart, injection of scleral vessels, hyperemia of the oropharyngeal mucosa, hypotension and pulse lability (remain for 2-3 weeks).

  • The Crimean-Congo hemorrhagic fever (CCHF) virus causes a number of outbreaks of viral hemorrhagic fever.
  • The fatality rate during outbreaks of CCHF reaches 40%.
  • The virus is transmitted to humans mainly from ticks and livestock. Human-to-human transmission can occur through close contact with the blood, secretions, organs, or other body fluids of infected people.
  • CCHF is endemic in Africa, the Balkans, the Middle East and Asia, in countries south of the 50th parallel north latitude.
  • There is no vaccine for humans or animals.

Crimean-Congo hemorrhagic fever (CCHF) is a widespread disease caused by a tick-borne virus (Nairovirus) of the Bunyaviridae family. The CCHF virus causes outbreaks of severe viral hemorrhagic fever with a case fatality rate of 10-40%.

CCHF is endemic in Africa, the Balkans, the Middle East, and Asian countries south of 50°N, the geographic limit of the tick, which is the main vector.

Crimean-Congo hemorrhagic fever virus in animals and ticks

CCHF virus vectors include a wide range of wild and domestic animals such as cattle, sheep and goats. Many birds are resistant to this infection, but ostriches are susceptible and may experience high rates of infection in endemic areas where they are a source of infection in human cases. For example, one of the past outbreaks of the disease occurred in an ostrich slaughterhouse in South Africa. There are no obvious signs of the disease in these animals.

Animals become infected by the bite of infected ticks and the virus remains in their bloodstream for about one week after infection, allowing subsequent tick bites to continue the tick-animal-tick cycle. While several types of ticks can be infected with CCHF, the Hyalomma ticks are the main vectors.

Transmission

The CCHF virus is transmitted to humans either by tick bites or contact with infected animal blood or tissues during and immediately after slaughter. Most infections occur in people employed in industrial animal husbandry, such as farm workers, slaughterhouse workers, and veterinarians.

Human-to-human transmission can occur through close contact with the blood, secretions, organs, or other body fluids of infected people. Hospital-acquired infections can also occur as a result of improper sterilization of medical equipment, reuse of needles, and contamination of medical supplies.

Signs and symptoms

The duration of the incubation period depends on the method of infection with the virus. After infection by a tick bite, the incubation period is usually one to three days, with a maximum of nine days. The incubation period following contact with infected blood or tissue is typically five to six days, with a documented maximum period of 13 days.

Symptoms come on suddenly with fever, myalgia (muscle pain), dizziness, neck pain and stiffness, back or lower back pain, headache, eye inflammation, and photophobia (sensitivity to light). Nausea, vomiting, diarrhea, abdominal pain, and sore throat may occur, followed by mood swings and confusion. After two to four days, excitement may change to drowsiness, depression, and fatigue, and abdominal pain may be localized in the right upper part with detectable hepatomegaly (liver enlargement).

Other clinical signs include tachycardia (rapid heartbeat), lymphadenopathy (swollen lymph nodes), and petechial rash (a rash caused by bleeding into the skin) on the inner surface of mucous membranes, such as in the mouth and throat, and on the skin. A petechial rash may progress to a larger rash called ecchymosis and other hemorrhagic phenomena. There are usually signs of hepatitis, and after the fifth day of illness, severely ill patients may experience a rapid deterioration in kidney function and sudden liver or lung failure.

The mortality rate for CCHF is approximately 30%, with death occurring in the second week of illness. In recovering patients, improvement usually begins on the ninth or tenth day after the onset of the disease.

Diagnostics

CCHF virus infection can be diagnosed by several different laboratory tests:

  • enzyme immunoassay (ELISA);
  • detection of antigens;
  • serum neutralization;
  • reverse transcriptase polymerase chain reaction (RT-PCR);
  • virus isolation in cell cultures.

Terminally ill patients, as well as patients in the first few days of the disease, usually do not produce measurable antibodies, so diagnosis in such patients is made by detecting the virus or RNA in blood or tissue samples.

Testing of patient specimens poses an extremely high biological risk and should only be performed under maximum biosecurity conditions. However, if specimens are inactivated (eg by virucides, gamma radiation, formaldehyde, exposure to high temperatures, etc.), they can be handled under basic biosecurity conditions.

Treatment

The main approach to the management of CCHF in humans is conventional supportive care with symptom management.

The antiviral drug ribavirin has shown clear positive results in the treatment of CCHF infection. Both oral and intravenous dosage forms are effective.

Disease prevention and control

Control of CCHF in animals and ticks

Robert Swanepoel/NICD South Africa

Prevention and control of CCHF infection in animals and ticks is difficult because the tick-animal-tick cycle usually goes unnoticed and infection in pets usually goes unnoticed. In addition, ticks that carry the disease are numerous and widespread, so the only practical option for properly managed livestock operations is to control ticks with acaricides (chemicals designed to kill ticks). For example, following an outbreak of the disease at an ostrich slaughterhouse in South Africa (mentioned above), steps were taken to ensure that ostriches remained tick-free in the quarantine facility for 14 days prior to slaughter. This measure helped to reduce the risk that the animal was infected at the time of slaughter and to prevent contamination of people who had contact with the animals.

There are no vaccines for use in animals.

Reducing the risk of human infection

Although an inactivated mouse brain-derived vaccine has been developed against CCHF and has been used on a small scale in Eastern Europe, there is currently no safe and effective vaccine available for widespread use in humans.

In the absence of a vaccine, the only way to reduce human infections is to raise awareness of risk factors and educate people about the steps they can take to limit exposure to the virus.

  • Reducing the risk of virus transmission from a tick to humans:
    • wear protective clothing (long sleeves, long trousers);
    • wear light-colored clothing that makes it easy to detect ticks on clothing;
    • use approved acaricides (chemicals designed to kill ticks) for clothing;
    • use approved repellents for skin and clothing;
    • regularly examine clothing and skin in order to detect ticks; if they are found, remove them by safe methods;
    • strive to prevent the infestation of animals with ticks or carry out the fight against ticks in premises for keeping animals;
    • avoid staying in areas where there are a large number of ticks and during the seasons when they are most active.
  • Reducing the risk of virus transmission from animals to humans:
    • wear gloves and other protective clothing when handling animals or their tissues in endemic areas, especially during slaughter, dressing and culling in slaughterhouses or at home;
    • keep animals in quarantine prior to their arrival at slaughterhouses or routinely treat animals with pesticides two weeks prior to slaughter.
  • Reducing the risk of human-to-human transmission in selected communities:
    • avoid close physical contact with people infected with CCHF;
    • wear gloves and protective clothing when caring for sick people;
    • wash hands regularly after caring for or visiting sick people.

Infection control in healthcare settings

Healthcare workers caring for patients with suspected or confirmed CCHF or handling specimens collected from them should follow standard infection control measures. These include basic hand hygiene, use of personal protective equipment, safe injection practices and safe burial practices.

As a precautionary measure, healthcare workers caring for patients directly outside the CCHF outbreak area should also follow standard infection control measures.

Samples taken from people with suspected CCHF should be handled by specially trained staff working in properly equipped laboratories.

Recommendations for infection control in the care of patients with suspected or confirmed Crimean-Congo haemorrhagic fever should be consistent with WHO recommendations for Ebola and Marburg haemorrhagic fevers.

WHO activities

WHO is working with partners to support CCHF surveillance, diagnostic capacity and outbreak response in Europe, the Middle East, Asia and Africa.

WHO also provides documentation to support research and control of the disease and has developed an aide-mémoire on standard precautions in healthcare settings that is designed to reduce the risk of transmission of blood-borne and other pathogens.

Crimean hemorrhagic fever is a very dangerous pathology. Timely diagnosis is essential to start treatment. Running processes are fraught with very serious consequences. The disease has an acute onset and proceeds with pronounced manifestations.

What is a disease

Crimean hemorrhagic fever is a viral disease. The causative agent belongs to the genus Arboviruses. The main carrier of the infection is the tick. This pathology has a high percentage of cases with a fatal outcome. The disease is common in warm climates. Farmers are more susceptible to this type of fever than others. According to statistics, such a viral disease affects mainly young men, it is less common in women. In children, the disease is detected in isolated cases and is extremely difficult due to a weak immune system. The risk of getting sick is in spring and summer, when ticks are especially active.

The disease is otherwise called Congo hemorrhagic fever - Crimea, Congo-Crimean fever, Central Asian hemorrhagic fever.

What is Crimean-Congo fever - video

Transmission routes and development factors

The main cause of the disease is the entry into the blood of the bunyavirus, which is transmitted by sucking a tick. The temperature favorable for the vital activity of an infectious agent is from 20 to 40 degrees, which allows it to live quite comfortably both in the body of an insect and animal, and in humans. There is also a contact method of transmission when the tick is crushed and the biological material of infected animals gets on the wound surfaces.

Bunyavirus - the causative agent of the Crimean hemorrhagic fever

The body of most people is very susceptible to the virus. You can also become infected through poor-quality sterilization of medical instruments. The weaker the immune response, the more severe the course of the disease. The virus is resistant to adverse environmental conditions and can only be destroyed by boiling.

Crimean hemorrhagic fever is common in many countries of the world.

The presence of chronic infections is one of the provoking factors of the acute course of the disease. With age, the risk of death increases.

Symptoms of hemorrhagic fever

The incubation period (from infection to the appearance of the first signs) of the Crimean hemorrhagic fever is from three to nine days. After a tick bite, the picture of the disease develops much faster than with another method of transmission. Among the first signs of the disease are the following:

  • increase in body temperature to high numbers;
  • severe weakness;
  • dizziness;
  • chills.

Then joint, muscle and headache join the clinical picture. There is nausea, vomiting and inflammation of the conjunctiva. In the future, irritability and aggression join, which are replaced by lethargy and apathy. During this period, body temperature often drops to normal levels, and then sharply increases again.

An increase in body temperature is the main symptom of the Crimean-Congo fever

As the process progresses from the third to sixth day, the infection affects the vascular bed. In this case, skin and other types of hemorrhages occur. These manifestations are fatal. The source of bleeding can be both the nasal mucosa and internal organs. Characteristic rashes appear on the skin.

Then, as a rule, confusion and low blood pressure join. The person may fall into a coma. If the disease has a favorable course, then recovery occurs on the 7th day with a gradual decrease in the severity of the main manifestations.

Diagnostic measures

Diagnostics is important. It is necessary to differentiate the disease from meningococcal infection, typhoid and influenza. To do this, a blood test is carried out to identify certain protective proteins-antibodies against the Crimean hemorrhagic fever virus. In addition, a lot of research is being carried out:


In addition to all of the above, the doctor examines the patient and, based on a combination of clinical signs, can make a diagnosis.

Main treatments: hospitalization, drugs

In the presence of Crimean hemorrhagic fever, urgent hospitalization of the patient is required to prevent life-threatening consequences. The treatment of the disease is symptomatic, since there is no remedy that could destroy the virus. In this case, the following groups of drugs are often used:

  1. Antipyretic. Used to reduce high temperatures. Most often, non-steroidal anti-inflammatory drugs are used, which not only relieve fever, but also relieve unpleasant pain symptoms. These drugs include Ibuprofen and Nurofen.
  2. Hemostatic. Aminocaproic acid is used to prevent serious complications. Additionally, ascorbic acid and Etamzilat are used to prevent bleeding. These funds strengthen the vascular wall and accelerate the adhesion of platelets. All medicinal substances are administered intravenously.
  3. Immunostimulants. This group of drugs is necessary to speed up the healing process and get rid of complications. The patient is injected with a solution of immune serum, which increases the body's resistance to the virus.
  4. Glucocorticoids. In severe cases of the main process, Dexamethasone and Hydrocortisone are used. These fast-acting drugs help to eliminate severe symptoms, reduce pain.
  5. cardiac glycosides. Used to prevent insufficient myocardial contractility. Most often, Digoxin and Strofantin are used, which allow regulating the activity of the heart muscle. These drugs are the prevention of congestion in the lungs and other internal organs.

To prevent dehydration and the removal of toxins, intravenous infusions of a solution of Albumin and Sodium chloride are used to replenish the fluid deficiency.

Drugs used for therapy, pictured

Ascorbic acid strengthens the wall of blood vessels
Strofantin is used to prevent heart failure
Dexamethasone relieves severe pain and skin manifestations
Ibuprofen relieves fever and pain
Aminocaproic acid prevents bleeding

Treatment prognosis and complications

With a timely approach to treatment and the normal functioning of the immune system, the prognosis of the disease is favorable. However, the virus causes an increased sensitivity in a person, so in most cases the disease is extremely difficult. Treatment should only be carried out in a hospital, as the death rate is at least 40% of all cases.

Early initiation of therapy in the first 3 days after infection allows you to achieve good results. A person is injected with a specific immunoglobulin. As a result, the likelihood of recovery increases several times. In each patient, the disease proceeds with varying degrees of severity of clinical manifestations.

After a fever, long-term immunity is developed. One of the dangerous consequences of the disease is infectious-toxic shock, in which the patient falls into a coma.

Vaccine and other preventive measures

To combat Crimean hemorrhagic fever, it is necessary to protect yourself from tick attacks.

A person who is going on vacation to countries with a warm climate is recommended to carry out preventive vaccination, which will allow developing specific immunity in the body.

Crimean hemorrhagic fever is a complex disease that at the initial stage can be confused with influenza. However, the symptoms increase very quickly and become extremely severe. At the first sign of the presence of the disease, you should immediately consult a doctor.