Zika fever: causes, symptoms, treatment, prevention

In the environment there is a huge number of viruses. Microorganisms that can not be seen with the naked eye, cause a person various diseases. Some of the pathogens lead to even a fatal outcome. The virus of Zeka is quite dangerous.

Pathogen of the disease

The fever of Zika is a disease caused by the eponymous virus. He is a representative of the genus Flavivirus. The virus was first detected in 1947 in the blood of a monkey that inhabited the forest of Zika (Uganda). That is why the name of the fever.

In 1948, scientists discovered Zik's virus in mosquitoes that lived in the same forest. Studies, which were subsequently carried out by specialists, showed that the causative agent can also infect humans. Cases of human infection were identified in 1952 (Uganda and United Republic of Tanzania).

Spread of fever

This disease for a long period of time was considered harmless. There were no epidemics associated with a disease such as Zick's fever. In which countries was the agent found? Antibodies to the virus were found in the inhabitants of Africa and Southeast Asia (Egypt, India, Vietnam, Indonesia, Central African Republic, Thailand, etc.). Interest in the disease arose in researchers in recent years, when the infection began to rapidly spread beyond its range.

The first outbreak of Zika fever was recorded on the islands of Yap, located in the Pacific Ocean and part of the Federated States of Micronesia. After conducting laboratory tests, 49 cases of infection were confirmed. A few years later, another outbreak was recorded in French Polynesia. In 2013-2014, 32 thousand people were examined. The national system of epidemiological surveillance registered more than 8 thousand suspected cases of the disease. Of these, 383 people confirmed BVVZ (disease caused by the virus Zika) after laboratory tests.

In 2014, the disease came to South America. The fever of Zeka was diagnosed among the inhabitants of Easter Island. About a year later, the RNA of the pathogen was detected in people living in the northeastern part of Brazil. From January 2015 to February 2016, cases of infection with the virus were registered in 44 countries around the world. BVVZ has become a global problem.

The first case of Zik fever in Russia

In Australia, China, Japan, Canada and Europe only "imported" cases of the disease are recorded. In Russia, too, the case of the importation of the fever of Zik by a tourist who returned to his homeland is fixed. A woman (36 years old) was vacationing in the Dominican Republic between January 27 and February 3, 2016. Several times she was bitten by mosquitoes, which caused the disease.

The fever of Zeka manifested itself on the day of return. The tourist felt a weakness, discomfort in the stomach. Arriving in Russia, she began to notice the following symptoms: loosening of the chair, headaches, rashes on the chest and hands, fever. A few days after the return, the woman was hospitalized in a state of moderate severity. Doctors noted her hyperemic oropharynx, a small rash on the face, trunk and extremities, an increase in the cervical lymph nodes, an increase in body temperature to 38 degrees.

The existing symptoms allowed doctors to presume the presence of one of such diseases as dengue fever and Zika fever. Treatment could be prescribed only after a precise diagnosis. To do this, specialists took samples of urine and blood for laboratory analysis. In the course of the studies, it was possible to detect the RNA of the Zick virus.

Transmission of pathogens through bites

The carriers of the virus are mosquitoes of the genus Aedes (Ae. Africanus, Ae. Aegypti, Ae. Albopictus). In the organism of insects, the pathogen gets after the bites of the patients of primates. How are monkeys infected - a question that modern science can not answer? The reservoir of the virus in nature is unknown.

In humans, Zik's fever occurs after sucking in infected mosquitoes. At the time of the bite, the viruses penetrate the human body, spread along it with blood flow through the vessels. This path of transmission of the causative agent is called transmissible.

Transmission of the virus by sex

In people infected with Zik fever, the pathogen was detected not only in plasma and serum, but also in semen, the secretion of the vagina. This fact allowed to suggest to specialists that the transmissive transmission path is not the only one. The virus can enter the body of a healthy person during intimacy with the patient.

The transmission of Zika's fever by sexual transmission is fixed in France, Italy, the USA, New Zealand, Argentina. The causative agent of the disease also appears in the saliva, the urine of sick people. However, at present there is no evidence to support the possibility of transmission of the virus through contact with these biological fluids.

Transmission of the virus to the fetus during pregnancy or childbirth

Zika fever can be transmitted to the child during pregnancy or childbirth. Vertical transplacental spread of the virus provokes intrauterine infection and the occurrence of malformations. Infection occurring during labor causes an innate infection.

Intrauterine infection can result in:

• To the defeat of the central nervous system;
• Delay in fetal growth;
• Placental insufficiency ;
• Death of the fetus.

With Zick's fever in early pregnancy, there is a high probability of microcephaly. By this term, specialists understand the too small size of the skull and brain. In children with this complication, the head does not grow after birth. Microcephaly is a fairly rare condition. However, in 2015-2016, the number of children born with this pathology increased significantly. This is due to the zik fever. During this period, more than 5 thousand births of babies with microcephaly from mothers infected with the virus were recorded.

Symptoms of the disease

After a mosquito bite, which carries the virus, the incubation period begins. Its duration can be from 3 days to 2 weeks. After the incubation period, the first symptoms appear. It should be noted that clinical manifestations of the disease develop only in 20-25% of infected individuals. So that doctors could suspect such a disease as Zick's fever, the symptoms should be observed as follows:

• Single increase in body temperature;
• Rashes on the trunk and extremities;
• joint pain;
• Inflammation of the eye mucosa.

Some patients complain of pain in the muscles and abdomen, frequent and frequent liquid stools, nausea, skin itching. However, these symptoms are extremely rare with Zik fever.

Conducting diagnostics

Plasma and blood serum, saliva, urine, sperm are a material suitable for detecting a disease such as Zick's fever. Diagnosis if necessary can be carried out by spinal and amniotic fluid, cord blood. At the death of the examined person, samples of internal organs (tissues of the liver, kidneys, brain, lungs) are studied.

In general, specialists only take blood. This procedure is performed in the morning. Blood in a volume of 3-4 ml is taken into a tube with an anticoagulant. It is then centrifuged to obtain a plazma. The resulting sample is stored before the polymerase chain reaction (PCR):

• Not more than 5 days at a temperature of plus 4-8 degrees Celsius;
• For 1 year at a temperature of minus 6-20 degrees;
• For a long period of time at a temperature of -70 degrees Celsius.

Serum is obtained by standard methods. It is stored until the moment of performing serological and molecular-genetic diagnostic studies in the same regimes as plasma.

Diagnosis is usually done on the 5th-7th day of the disease and after 7-10 days. In the first week of the disease, polymerase chain reaction (PCR) in the blood samples taken reveals the virus of Zik fever - or rather, its RNA. Antibodies of IgM class are found approximately on the 5th-6th day of fever. By the end of the second week of the disease, antibodies of IgG class appear in the blood of infected people.

Treatment of fever

In all countries of the world, with the exception of Russia, the hospitalization of people with symptoms of the disease caused by the Zick virus is carried out only if there are clinical indications. In Russia everything is different. All patients with suspicious symptoms are hospitalized in an infectious hospital, where they undergo examinations.

The fever of Zika, the symptoms of which are manifested, usually proceeds in mild form. Doctors prescribe patients antipyretic agents, recommend a lot of rest and drink more fluid. Etiotropic therapy, which can eliminate the cause of Zick's fever, does not exist. Research institutes and international companies are working on the development of antiviral drugs. However, it has not yet been possible to develop a product that could destroy the pathogen in the human body.

Particular attention should be paid to the management of pregnant women with Zika fever. When diagnosing this disease, women in the position are not recommended to prescribe acetylsalicylic acid. In the first trimester of pregnancy, a comprehensive examination is needed. Ultrasound is performed, invasive prenatal diagnostic methods are used. The results obtained make it possible to resolve the issue of maintaining a pregnancy.

Possible complications

In 2015, an outbreak of BVVZ was registered in Brazil. Experts who assessed the situation noted that with the increase in the number of infected people, the number of patients with Guillain-Barre syndrome increased. This is a condition in which the human immune system affects the peripheral nervous system.

In most cases, the Guillain-Barre syndrome in humans is mild. Patients report weakness and tingling in their lower and upper limbs. Some people have paralysis of the legs, hands, facial muscles. In severe cases Guillain-Barre syndrome leads to paralysis of the respiratory muscles, cardiac arrest. As a result, death occurs.

Patients with Guillain-Barre syndrome caused by Zick's fever should be carefully monitored (blood pressure, palpitations, and respiration are needed). That's why sick people even in the mild course of this complication are hospitalized.

Preventive measures

In order not to face such a disease as Zick's fever, prevention should consist of the following:

1. People choosing a place to relax abroad should pay attention to countries that are free from epidemiology.
2. If the holiday is planned in the state where mosquitoes are the sources of the fever, then it is recommended to take repellents with them. For protection from insects, you can use light clothing covering most of the body.
3. In hotels, do not open windows, unless they are equipped with mosquito nets.
4. You should also avoid visiting wetlands. Tanks with water (car tires, flower pots) should be emptied and cleaned (or covered), because mosquitoes like a damp and cool atmosphere.

Do not forget that BWVZ can be transmitted sexually. On return from rest for 8 weeks (in the absence of symptoms), one should adhere to safe sexual behavior (use condoms or avoid intimate contacts). When the first signs of the disease appear, this way of life will have to be carried on for 6 months (at least).

In conclusion, it should be noted that the zik fever (clinic, epidemiology, treatment and prevention of the disease) - this is an urgent topic. An illness that was not taken seriously for a long period of time, in recent years has become a threat to the health and life of the majority of the inhabitants of the planet. Currently, BVVZ is not yet fully understood: all complications that may arise due to the pathogen are not known, vaccines and drugs against the virus have not been developed. Perhaps these issues will be resolved in the near future, because international organizations and research institutes are working in these areas.