The Zika virus is a spherical arbovirus with a diameter of no more than 40-45 nm, belonging to the Flaviviridae family, capable of causing a disease known as Zika fever when entering the human body.
Zika virus is a spherical arbovirus
The Zika virus was first isolated from the blood of rhesus monkeys in the tropical forests of Uganda in 1947, hence the name (“Zika” means “thicket” in the local indigenous language).
The Zika virus was discovered in human blood 5 years after its discovery, amid outbreaks of the disease in Nigeria, Tanzania and Uganda. Over the following years, epidemics of Zika fever were periodically recorded in many countries of the African continent (which is due to the presence of optimal living conditions for the carrier of the Zika virus: a hot, humid climate).
It is believed that the spread of the Zika virus eastward across the Pacific Ocean began in 2007, reaching South and Central America, some regions of India, French Polynesia and other territories within 7-8 years. Currently, isolated cases of the disease are being reported in some European countries.
The largest Zika epidemic on record began in 2015, spreading to more than 30 countries and regions in both the Americas. According to some reports, in Brazil alone the number of infected people has reached one and a half million.
The World Health Organization announced that 3–4 million people had been infected with the Zika virus, and the disease was declared a pandemic at the end of 2016.
At this point, Zika is officially considered an international public health threat, even though the potential of the virus is not fully understood.
Features of the spread and transmission of the Zika virus
The Zika virus is transmitted by tropical mosquitoes of the genus Aedes; the causative agent of the disease enters the human body at the time of the bite of a blood-sucking insect.
The bulk of arboviruses migrate between animals, which are their main hosts, and blood-sucking arthropods.
In typical cases of arboviral infections, a person is a dead-end branch for the development and reproduction of pathogens, since the concentration of viral particles in his body is insufficient to be released into the external environment in significant concentrations to infect others.
The Zika virus (along with a few other pathogens of tropical infections) in this regard is an exception to the rule, since it reaches high concentrations in the internal environments of the human body: it is determined in the blood, urine, saliva, seminal fluid, cerebrospinal fluid, and amniotic fluid.
The Zika virus is transmitted by tropical mosquitoes of the genus Aedes.
To date, the following routes of transmission of the Zika virus from an infected person to a healthy person have been reliably confirmed:
- when transfusing infected blood (the danger lies in the long incubation period of Zika fever, when the donor does not know that he is infected: in some cases, symptoms appeared in donors 1-2 weeks after they donated blood);
- through sexual contact (there are no cases of transmission of the Zika virus by women to men);
- in utero from an infected mother to the fetus.
Of particular concern is the vertical transmission of infection caused by the Zika virus, from mother to fetus.
During the epidemic that began in 2015, in Brazil alone, according to some data, there was a 20-fold increase in the birth rate of children with central nervous system pathology, mainly microcephaly (abnormally small size of the head and, as a result, the brain).
When Zika virus is transmitted from mother to fetus, there is a high risk of having a baby with microcephaly
Some children exposed to the Zika virus in utero experience seizures, dysfunction of brain stem structures, hearing and vision abnormalities, and other neurological abnormalities. Collectively, congenital pathologies associated with exposure of the fetus to a pathogenic agent during pregnancy are known as congenital Zika virus syndrome.
In Latin American countries, the leadership of some states has officially recommended that couples planning to have children give up pregnancy until the epidemiological situation improves.
Forms of Zika fever
The infection occurs in several forms depending on the severity of the process:
- asymptomatic;
- light;
- moderate severity;
- heavy.
More than 2/3 of all cases of Zika fever are either asymptomatic or in an erased form.
Severe forms of infection caused by the Zika virus are extremely rare, and deaths from the disease are rare. Mortality from the disease is not reliably related to previous infection with the Zika virus, and theoretically the disease is considered non-fatal.
The Zika virus was first isolated from the blood of rhesus monkeys in the tropical forests of Uganda in 1947, hence the name (“Zika” means “thicket” in the local indigenous language).
Symptoms of Zika fever
Zika fever is currently not well understood. Presumably, primates and humans serve as natural reservoirs for the virus: for some animal species the virus is deadly, but in some, on the contrary, it does not cause any symptoms of the disease.
The duration of the incubation period (the time from the moment of infection to the appearance of the first clinical manifestations of the disease) is not reliably known; the majority of researchers are inclined to believe that its duration varies from several days to one and a half to two weeks.
The obvious form of the disease has the following symptoms:
- weakness, drowsiness, deterioration in general health;
- pain in the eyeball area;
- conjunctivitis, photophobia (intolerance to bright light);
- moderate headache;
- temperature rise to low-grade levels, in some cases chills are possible;
- soreness in muscles and joints;
- a small rash, consisting of hard blisters with liquid contents no more than 1 cm in diameter, initially appears on the face and torso, then spreads over the entire surface of the skin;
- sore throat, sore throat or rawness, accompanied by enlargement of regional lymph nodes (submandibular, anterior and posterior cervical);
- dyspeptic symptoms: nausea, diarrhea, abdominal pain, vomiting (rare).
In the obvious form of Zika fever, pain in the eyeballs, weakness, and deterioration of health occur.
Symptoms of Zika fever resolve spontaneously within 2 to 7 days. After recovery, stable lifelong immunity is formed.
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Diagnosis of Zika fever
Diagnosing Zika virus infection is challenging. This is due to the following reasons:
- a large number of cases of asymptomatic Zika fever (up to 75%);
- multiple routes of transmission;
- imperfection of specific laboratory methods for detecting the virus;
- molecular evolution of the virus.
Criteria to suspect Zika virus infection:
- the patient has characteristic skin rashes, possibly accompanied by an increase in body temperature and at least one of the following signs: joint pain, arthritis, non-purulent conjunctivitis;
- the presence of IgM antibodies to the Zika virus in the blood;
- contact with a person with a confirmed diagnosis or stay in a region with an unfavorable epidemiological situation no earlier than 2 weeks before the appearance of the first symptoms of the disease.
This is what a Zika virus rash looks like
The following laboratory test results can reliably confirm the presence of Zika fever:
- presence of Zika virus DNA or antigen in serum or other samples (eg, saliva, tissue, urine, whole blood); or
- a positive reaction to IgM antibodies to the Zika virus and a PRNT90 titer for the Zika virus ≥ 20, and a PRNT90 titer coefficient for the Zika virus in relation to other flaviviruses ≥ 4; and exclusion of other flaviviruses.
The largest Zika epidemic on record began in 2015, spreading to more than 30 countries and regions in both the Americas.
The virus is detected in the body of an infected person for approximately a week after infection.
Treatment of Zika fever
There is no specific treatment for Zika virus infection. Known antiviral drugs do not have the desired effect on the causative agent of the disease.
Pharmacotherapy is aimed at eliminating the symptoms of Zika fever:
- antihistamines;
- detoxification therapy;
- antipyretic drugs;
- non-steroidal anti-inflammatory drugs for intense myalgia and arthralgia.
Possible complications and consequences of the disease
Complications of Zika fever can include:
- damage to fetal brain structures due to intrauterine infection (usually microcephaly);
- Guillain-Barré syndrome (a rare autoimmune disease manifested by damage to peripheral nerves).
Despite the fact that the outcome of Guillain-Barré syndrome can be complete immobilization, in the vast majority of cases, even with extremely severe forms of the pathology, regression of painful symptoms and complete recovery of patients occurs.
Of particular concern is the vertical transmission of infection caused by the Zika virus, from mother to fetus. This is fraught with the birth of children with central nervous system pathologies, mainly microcephaly.
Forecast
The prognosis is generally favorable, the disease resolves without specific treatment, after which stable immunity is formed.
Preventing Zika virus infection
Since the danger of Zika fever has been confirmed internationally, the World Health Organization has developed recommendations for the prevention of the disease in places with unfavorable epidemiological conditions:
- protection against insect bites (using repellents containing DEET, IR3535 or icaridin, wearing clothing that maximally protects the surface of the body and preferably light colors, installing mosquito nets on windows, curtains on beds);
- eliminating favorable conditions for mosquito breeding (covering or emptying water containers, cleaning decorative ponds, drying up gutters, etc.);
- the use of reliable contraception during sexual contacts in unfavorable epidemic conditions.
- WHO is currently developing effective antiviral agents, vaccines and accessible diagnostic techniques to combat the Zika virus.
- Video from YouTube on the topic of the article:
Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher education, 2004 (State Educational Institution of Higher Professional Education “Kursk State Medical University”), specialty “General Medicine”, qualification “Doctor”. 2008-2012
– postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty “pharmacology, clinical pharmacology”). 2014-2015
– professional retraining, specialty “Management in Education”, Federal State Budgetary Educational Institution of Higher Professional Education “KSU”.
The information is generalized and is provided for informational purposes. At the first signs of illness, consult a doctor. Self-medication is dangerous to health!
Source: https://www.neboleem.net/virus-zika.php
Zika fever
Zika fever is an acute infectious disease with a predominantly vector-borne transmission mechanism. The disease is asymptomatic or manifests itself with increased body temperature, general intoxication syndrome, pain in muscles, joints, conjunctivitis, and rash. The main danger of infection is the formation of microcephaly and various neurological disorders in the fetus in case of infection of pregnant women, as well as persistent pathologies of the central nervous system in adults. Diagnostics is based on the detection of the virus itself in biological material, as well as specific antibodies in human blood serum. Etiotropic treatment has not been developed. Symptomatic therapy is carried out.
The virus was first isolated from the blood of a monkey living in the Zika forest in Uganda. Translated from the local dialect, “zika” means “thickets.” Endemic areas for this infectious disease are the countries of Central and South America, Africa, Southeast Asia, and the Pacific Islands.
In other countries, examples of infection have also been recorded, but they are caused by imported cases among travelers. Since 2015, about 4 million cases have been recorded. In 2016, WHO declared an international health emergency due to the outbreak.
Such caution is associated with the pronounced teratogenic effect of the virus and the lack of specific treatment.
Receptivity is universal. Seasonality is not pronounced, but there is an increase in cases of infection during heavy rains, which is associated with an increase in the activity of mosquito vectors.
With the development of global warming, the distribution area of the corresponding insects is increasing, which creates an even greater danger for humans. However, the virus cannot tolerate low temperatures.
Therefore, the formation of persistent foci of fever in countries with a temperate climate is impossible, but imported cases can contribute to the development of outbreaks in the summer.
Zika fever
The causative agent of the disease is an RNA virus from the Flaviviridae family. Belongs to arboviruses. The pathogen is quite stable in the environment. In a lyophilized state, it can be stored for up to 30 months.
Phenol and low-percentage ethyl alcohol do not kill the microorganism, however, it is quickly inactivated upon contact with ether, a solution of potassium permanganate. There are two lines of the virus: Asian and African.
The African form is believed to be a parasite in monkeys, with humans being the occasional host. The Asian lineage was isolated from the majority of patients during epidemics in endemic areas.
The source of infection is monkeys and sick humans. The disease is transmitted through a vector-borne mechanism using Aedes mosquitoes. Possible sexual, parenteral (through transfusion of blood components), transplacental, contact (with saliva) routes of infection. The sexual tract occurs only in men.
Some authors have expressed the possibility of aspiration infection in immunocompromised individuals. The virus is found in blood, saliva, urine, semen, breast milk, and amniotic fluid during intrauterine infection. The danger is posed by the transmission of the Zika virus during blood transfusions and organ and tissue transplantations, because
in most cases, the disease is asymptomatic; there is no specific screening of donors, which can lead to iatrogenic infection of recipients.
The mechanism of development of this infectious disease is not fully understood. It is believed that dendritic cells are the first to be affected at the site of the bite. The virus then spreads through the bloodstream to various organs and tissues. RNA replication occurs in infected cells of the human body.
During the release of new virion particles from the cell, cytolysis of the affected structures develops. When studying microslides, morphological changes were found in skeletal muscles and myocardium (swelling of fibers, necrosis, proliferation of nuclei, disappearance of transverse striations).
Experiments on laboratory animals have proven the high tropism of the virus to cells of the nervous system. In the case of intrauterine infection, the pathogen affects the chorionic villi and the vessels of the placenta. Persistent fetal ischemia occurs.
In addition, the Zika virus affects the mitotic activity of cells, which in turn leads to the formation of developmental defects.
In four out of five cases, the infection is asymptomatic. The incubation period ranges from 3 days to 2 weeks. A person becomes contagious several days before the first symptoms appear.
Characterized by the presence of low-grade fever, which lasts up to 5 days. There is weakness, lethargy, drowsiness, and a feeling of malaise. Typical symptoms include myalgia, arthralgia, pain in the eyeballs, and photophobia.
Conjunctivitis and swelling of small joints often develop.
From the first day of the disease, a small itchy maculopapular rash appears on the face and torso, followed by possible spread throughout the body. Elements can increase in size and merge.
Sometimes blisters with transparent contents form. Very rarely, dyspeptic symptoms occur in the form of nausea, vomiting, diarrhea, a feeling of heaviness, and epigastric pain.
The duration of the disease is about 7 days.
In pregnant women and children infected through a non-transplacental route, the disease occurs with typical clinical symptoms. It is believed that after an infection, stable immunity is formed, and re-infection is unlikely.
The most serious complication in adults who have recovered from Zika fever is the development of Guillain-Barré syndrome. There is no direct evidence linking this neurological disorder with infection, however, according to studies in countries at risk, more than 90% of patients with Guillain-Barré syndrome had antibodies to the Zika virus.
The greatest danger is infection of women during pregnancy, especially during critical periods of fetal development.
It is characterized by interruption of gestation in the early stages, the formation of fetoplacental insufficiency, developmental defects, damage to the central nervous system with the development of microcephaly and brain malformations.
In some cases, pathology of the optic nerve occurs. Many authors associate the Zika virus with the development of meningoencephalitis, myelitis, and hemorrhagic complications.
During an objective examination, no specific symptoms are revealed. The presence of a rash, conjunctivitis, and possibly swelling of small joints is noted.
This disease most often occurs in a mild form, so those infected rarely seek medical help. If Zika fever is suspected, consultation with an infectious disease specialist is necessary.
The following clinical and laboratory methods are used in diagnosis:
- Virus detection. Viral RNA is identified using reverse transcription PCR. This method is most informative from 3 to 7 days from the onset of the disease. Blood serum is used as the test material. Research studies also look at urine and semen.
- Serological methods. The dynamics of the increase in the titer of specific IgM antibodies is determined by ELISA. This method may give false-positive results due to the possibility of cross-reactions with other flaviviruses.
- Ultrasound of the fetus. Sonography makes it possible to identify fetal malformations at the antenatal stage. Signs of microcephaly with a decrease in head circumference, the presence of intracranial calcifications, and ventriculomegaly are determined.
- Amniocentesis. There is no consensus on the need for testing in infected pregnant women. The Zika virus is detected in amniotic fluid 6-8 weeks after the mother is infected. In addition, the degree of pathogen release into the amniotic fluid depends on the maturity of the fetal kidneys.
WHO identifies the following criteria for diagnosing Zika fever: suspected, possible and confirmed cases. A presumptive case is based only on the presence of clinical symptoms. A possible case includes the absence of a clinic, detection of IgM in the blood, and a burdened epidemiological history.
A confirmed variant is characterized by the detection of viral RNA, IgM in a diagnostically significant titer, and the exclusion of infection with other flaviviruses.
Differential diagnosis is carried out with yellow fever, dengue fever, chikungunya, rubella, malaria, HIV infection, leptospirosis, measles, rickettsiosis, infection with parvovirus, enterovirus, adenovirus, streptococcal infection.
Specific drugs for the treatment of Zika virus infection have not been developed to date. Symptomatic treatment is carried out. Patients are advised to drink plenty of fluids for detoxification purposes. In case of severe intoxication syndrome, infusion solutions are prescribed.
Until dengue fever has been ruled out, NSAIDs should be avoided to prevent hemorrhagic complications. The use of non-steroidal drugs in pregnant women up to 32 weeks can cause premature closure of the ductus botalus in the fetus. Antihistamines may be prescribed to reduce itching.
Some authors recommend taking drugs that activate the immune system (ginseng, eleutherococcus).
The prognosis is relatively favorable. In most cases, this viral infection occurs in mild forms. However, long-term consequences are associated with the development of severe neurological complications. The virus is also associated with the formation of malformations in the fetus and termination of pregnancy in the early stages of development. Statistical studies demonstrate a similar connection.
Specific prevention has not been developed. Non-specific protection measures include the use of repellents, mosquito nets in ventilated areas, long sleeves, destruction of mosquito breeding sites, and the use of air conditioners.
Pregnant women and women planning pregnancy are not recommended to visit countries where the infection is spreading. An algorithm is being developed to screen all pregnant women returning from countries at risk for Zika fever.
Men should use barrier methods of contraception when returning from travel to endemic areas for at least a month, although there is evidence of virus shedding from semen for up to 60 days.
Source: https://www.KrasotaiMedicina.ru/diseases/infectious/Zika
Zika virus: what is it and should you worry?
If a pregnant woman has had the Zika virus, this increases the risk of giving birth to a child with brain damage. There is no vaccine for the virus, no specific medicines, and there is no way to protect a child from its effects. The only good news is that the virus and its complications are rare.
The Zika virus in 20% of cases is manifested by fever, rash, joint pain, and conjunctivitis. Most of the sick get away with a slight increase in temperature or do not feel any symptoms at all. All signs of the disease disappear in two days, maximum in a week.
The Zika virus belongs to the flavivirus genus and is a relative of yellow fever and dengue fever. All these diseases are carried by mosquitoes.
Until recently, little attention was paid to the Zika virus. It was rare and was not associated with serious illnesses. But an outbreak in Brazil in 2015 found a link between the virus and microcephaly in newborns.
Even Rospotrebnadzor recommended that pregnant women refrain from traveling to countries where the virus is widespread.
The exact connection between the Zika virus and microcephaly has not been proven, but it is highly likely. The virus reached Brazil recently, possibly during the 2014 FIFA World Cup. This was followed by an outbreak of microcephaly cases. The virus may spread further: the 2016 Summer Olympics will be held in Rio.
The Brazilian government reports 4,000 cases of children being born with a head circumference of less than 33 cm. For comparison, there are usually no more than 150 such cases per year in the country.
The figure may be inflated: most children are healthy, despite their small head sizes. In addition, in some people microcephaly is caused by other reasons.
But even if we discard these exceptions, everything else points to the harm of the Zika virus.
Should anyone other than pregnant women need to worry?
It's worth worrying about. A possible complication that affects not only pregnant women is Guillain-Barré syndrome. This is a rare disease in which the body's immune system attacks its own nerve cells. As a result, paralysis may develop. The syndrome is triggered by infectious diseases - from enteritis to influenza.
The connection between the Zika virus and Guillain-Barre syndrome, as already mentioned, has not been proven. But in Brazil, too, surges in the incidence of the Zika virus and this syndrome coincided in time.
The Zika virus can also be transmitted sexually. In the United States, such a case has already been recorded: one of the partners traveled to a region where the virus is widespread and infected the other.
At least two more similar cases (one occurred in 2007, the other in 2011) indicate this possibility.
Scott Weaver, an infectious disease specialist, commented on these cases in an interview with The New York Times:
If I had symptoms of the Zika virus and my wife was of reproductive age, I would take extra protection for a few weeks.
Scott Weave
If sexual transmission exists, it occurs rarely. But this does not mean that it should be brushed aside. So, if you travel to dangerous regions, do not forget to protect yourself at home.
There is one more important point. Even if you are not planning a child, but theoretically you can become pregnant, you need to take the same precautions as pregnant women. In other words, before the trip, during it and for some time after it, you need to protect yourself with special attention and meticulously choose repellents. You never know.
Will repellents help?
They will help. Nothing is 100% guaranteed, but repellents containing DEET are effective at repelling mosquitoes. Products with natural ingredients will also work.
DEET is safe when used correctly, including during pregnancy. Renew your protection in time, because after a few hours the effect of repellents decreases.
Which regions are dangerous and will the Zika virus come to Russia?
A complete list of countries that may be dangerous to visit is provided here. The list contains more than 25 items, including island states.
Outbreaks of microcephaly are shown in the map below. This is a screenshot of an interactive map where you can find detailed information.
The Zika virus was first recorded in Africa in 1947, but there it did not reach epidemic proportions; only isolated cases were encountered.
It is transmitted by mosquitoes of the yellow fever mosquito species. It can be identified by its small white spots. Insects are active during the day. Not all regions where mosquitoes live experience disease outbreaks, but if there are carriers, then the disease can appear.
Distribution area of Zika virus vectors. Wikipedia
Disease carriers are unlikely to take root in Russia. These mosquitoes prefer warmer climates. The only spread option is to bring the virus from abroad, from hot countries.
What risk does a trip to a dangerous region create for an unborn child?
Small. In Brazil, the 4,000 cases of microcephaly mentioned above account for 0.1% of all newborns.
The risk of damage to the fetus is comparable to the risk created by cytomegalovirus during primary infection during pregnancy.
And earlier, until there was a vaccine against measles, rubella and mumps, rubella was the main cause of microcephaly. That is, the risk of getting microcephaly from the Zika virus is even less than from common diseases.
So even in Brazil it is difficult to get sick, especially using repellents. But it still makes sense for pregnant women to postpone their trip.
How to determine if a child has suffered from the Zika virus
Be sure to tell your doctor that you have been to a high-risk country if you are pregnant. Especially if you have a rash, fever, or red eyes. The disease is treated symptomatically, like any viral disease. Pregnant women may require additional examinations:
- Blood test using PCR to detect the virus or the presence of antibodies in the blood serum.
- Amniocentesis is the removal of amniotic fluid to test for the presence of a virus. But this method itself is associated with a risk for pregnancy, so it is used as a last resort.
- Regular ultrasound examinations every 3-4 weeks, which will allow you to monitor the development of the child’s brain.
The tricky part is this: you can't predict exactly how test results will affect the chances of having a baby with microcephaly. The same ultrasound examination cannot show the development of this disease during pregnancy up to 24 weeks.
So if you suddenly contract the Zika virus, you find yourself in a difficult situation with many unknowns. No one knows what a positive blood test will lead to and how the virus will affect the child.
How the Zika virus affects children later in life
“Microcephaly is a black box,” writes Brazilian journalist Ana Caceras. The doctors said that she would not walk or talk. But they were wrong.
However, in most cases, doctors are right: microcephaly entails serious consequences, children die early. Moreover, the Zika virus is precisely associated with the most difficult cases.
This is still a new discovery, so it is difficult to predict how children born with microcephaly due to the virus will develop. Cytomegalovirus, for example, destroys stem cells in the brain so that nerve tissue simply does not develop as well as it should. The Zika virus may work the same way.
Microcephaly is irreversible; treatment can only achieve the maximum possible development of such children.
What are people doing around the world about this?
Without a vaccine and specific medicine, much cannot be done. Countries are issuing travel advisories and advising pregnant women to avoid traveling to dangerous places.
In Brazil and El Salvador it is proposed to postpone pregnancy (in El Salvador - until 2018). This advice is not easy to follow (especially in El Salvador, where contraception is expensive and the most popular method of birth control is sterilization).
The World Health Organization works in several directions:
- Development of diagnostics and tests. This is a more important task than developing a vaccine and treatment. Without good testing, it is impossible to tell who needs treatment or how far the disease has spread.
- Mosquito population control. People need protective equipment to reduce the risk of infection.
- Providing medical care to countries experiencing an epidemic. For example, neurologists and physiotherapists are needed there to help children with microcephaly.
- WHO does not impose restrictions on visiting countries where the virus is widespread. But some countries do not recommend pregnant women to visit dangerous regions.
In the near future, the most effective way to combat the Zika virus will be disinsection - mosquito control.
This includes the elimination of reservoirs with stagnant water, and the use of insecticides, and genetic changes in male mosquitoes (which do not leave offspring), and infection of mosquitoes with Wolbachia - bacteria that make insects infertile. It sounds creepy, but “microcephaly” doesn’t sound any better.
Since mosquitoes spread many diseases, the hysteria surrounding the Zika virus could help combat them, too.
A vaccine is already in development and may be tested before the end of the year. The blind spots regarding the impact of the Zika virus should be closed in the coming years: affected children will grow and develop as much as possible, and doctors will look for the most effective methods of rehabilitation.
So right now it’s difficult to say how dangerous the virus is. While this issue is being studied, it is better to be safe.
Source: https://Lifehacker.ru/virus-zika/
Zika virus: symptoms, modes of transmission, diagnosis and treatment
Zika virus is the virus that causes Zika fever or Zika disease. The carrier (source of the disease) is mosquitoes of the genus Aedes. In 1947, the virus was first recorded in Uganda in macaques living in the Zika forest, then in 1952, Zika fever was identified in citizens of Uganda and Tanzania.
The reservoir of the disease is unknown. The virus itself belongs to the genus Flaviviruses. The incubation period of the disease caused by the Zika virus is not known for certain, however, based on observations of patients, it can be assumed that it is several days.
| Zika virus: basic data | |
| Source of infection | Aedes mosquitoes |
| Incubation period | several days |
| Symptoms |
|
| Diagnostics | PCR method |
| Treatment | symptomatic |
| Prevention |
|
Symptoms of Zika virus disease
The first manifestations of the disease are similar to typical arboviral fevers, such as dengue fever. Symptoms of Zika virus infection include:
- High body temperature.
- Rash (exanthema - spotted papular rubella-like rash) on the skin.
- Development of conjunctivitis.
- Presence of muscle pain and joint pain.
- Headache.
All symptoms of the Zika virus are mild, usually their manifestations persist for 2 to 7 days.
During periods of massive outbreaks of the Zika virus, possible complications were recorded, including autoimmune and neurological disorders. Similar cases were recorded in 2013 in French Polynesia and in 2015 in Brazil. All complications were studied and described by national health authorities.
Also during these two major outbreaks, a link was identified between the Zika virus and the birth of infants with microencephaly, a disorder of brain development in which the brain mass and skull size are smaller than normal.
Microencephaly is a cause of mental retardation, which affects the length and quality of life of the patient.
It is impossible to prevent the development of this disorder, just as there is no treatment (only symptomatic).
Now virologists, neurologists and perinatologists continue to study the true impact of the Zika virus on the development of intrauterine fetal disorders, and also study possible other consequences of the disease caused by the Zika virus.
Source of the disease
The Zika virus is transmitted by mosquitoes, in particular Aedes aegypti, whose habitat includes countries in the tropical region. Aedes mosquitoes are also responsible for outbreaks of dengue and chikungunya fevers and yellow fever.
Due to the fact that the source of infection is mosquitoes, the Zika virus spreads quickly, so if from 1947 to 2007 (over 60 years) only 15 cases of the disease were described, then already in 2014 the Zika virus was identified in 23 countries of America, and in In 2016, it was discovered in 8 European countries (Italy, Switzerland, Finland, Portugal, Germany, Denmark, Sweden, France).
Speaking about other ways of transmitting the Zika virus, the disease is not transmitted through airborne droplets or through personal contact with a patient. However, a case of sexual transmission of the virus has been described in the United States.
Scientists have confirmed that one case of infection was recorded after sexual contact, but such confirmations were not recorded en masse, so there is no reason to assert that there is a 100% risk of this method of transmitting the virus.
Diagnosis of Zika virus
- Because the disease caused by the Zika virus is mild, in some cases even undetectable, diagnosis is carried out only if an outbreak of the disease is confirmed or the patient has returned from an area with an increased risk of infection.
- It is also unlikely to suspect the disease on your own, since the Zika virus does not cause specific symptoms and/or signs.
- Diagnosis is made in a laboratory using polymerase chain reaction or PCR and detection of the virus in patient blood samples.
- Differential diagnosis of Zika virus is carried out to exclude the presence of dengue fever, West Nile virus and yellow fever.
Treatment for Zika virus
Zika fever, or the disease caused by the Zika virus, most often occurs in mild forms and does not require specific treatment or the development of specific antiviral drugs. Patients with the Zika virus are advised to rest, drink plenty of fluids, and take medications to relieve unpleasant symptoms (fever, body aches, fever).
If your illness worsens or new, previously unknown symptoms appear, you should immediately seek professional medical help.
Preventing the Zika virus
Due to the specific causes of the spread of the Zika virus (bites from Aedes mosquitoes), the main and most reliable way to prevent infection is to avoid visiting countries and regions where cases of the disease caused by the Zika virus have been confirmed.
People staying in dangerous regions and at particular risk of infection are recommended to use repellents (sprays, ointments and other products containing chemicals that repel insects, in particular mosquitoes). They should also wear light-colored clothing that covers their body as much as possible, use screens for doors and windows, and mosquito curtains.
In regions affected by the Zika virus outbreak, insecticides may be sprayed to reduce mosquito populations by order of local authorities or on WHO recommendations. Near bodies of water, the use of larvicides capable of destroying the larvae and caterpillars of potentially dangerous insects is indicated.
As for specific prevention of the Zika virus, it has not been developed to date. However, according to scientists and global pharmaceutical giants, a vaccine against the Zika virus will be ready by the end of 2016. The development is carried out by Laval University (Canada), the University of Pennsylvania (USA), Inovio Pharmaceuticals (USA) and GeneOne Life Science (South Korea).
Source: https://www.eurolab.ua/encyclopedia/323/49591/
Zika virus: who is it dangerous for and how to protect yourself from it
/TASS/. In early February, the World Health Organization (WHO) declared the Zika outbreak in the Americas an international health emergency. The fever caused by the Zika virus has long been considered harmless to humans.
However, after its rapid spread in Brazil, it became clear: this disease can lead to irreversible consequences, and the complications that arise in people as a result of infection require urgent scientific research.
In a matter of weeks, Zika has gone from being a regional exotic disease of interest only to the scientific community to a problem that affects millions of people across the planet.
Where did the name Zika come from?
The virus was first discovered in 1947 in Uganda in rhesus monkeys living in a forest called Zika. Until recently, it was identified only in African and Asian countries, as well as in the island countries of the Pacific region. However, in May 2015, Zika fever was diagnosed in residents of Brazil.
There are two versions explaining the appearance of the virus on the South American continent. According to one of them, it could have been brought from Africa during the FIFA World Cup held in Brazil in 2014. Another hypothesis is that the virus entered the largest country in South America from Micronesia.
Currently, cases of Zika fever have been reported in more than 20 countries in Latin America and the Caribbean, as well as in the United States and several European countries.
What is the danger of the virus
Microcephaly. In November 2015, the Brazilian Ministry of Health confirmed that infection with the virus during pregnancy causes microcephaly in the child - a birth defect that consists of a significant reduction in the size of the skull and is accompanied by mental retardation, neurotic disorders, hearing and vision impairment.
The country's authorities are recording an increase in cases of births of children with microcephaly.
According to the latest data, from October 22 (when authorities began keeping relevant statistics) to January 23, 4,180 possible cases of microcephaly in infants were registered in the largest South American country, which is more than 25 times higher than in 2014, when the number of sick children did not exceed 150.
In turn, WHO Director General Margaret Chan said that “a cause-and-effect relationship between the Zika virus, developmental defects and neurological syndromes has not yet been established, but there are strong suspicions about its existence.”
Guillain-Barre syndrome. Some researchers believe that the Zika virus poses a danger not only to children, but also to adults. It is believed that fever can lead to the development of a rare autoimmune disease - Guillain-Barré syndrome.
It is characterized by paresis (partial paralysis) of the lower extremities, which after a few days or even hours spreads to the arms and then to other muscles of the body. The main danger is that it can affect the respiratory system, in which case the person risks dying from lack of oxygen.
In addition, in some cases, Guillain-Barré syndrome causes some of the person's muscles to remain paralyzed for life.
Lack of vaccine. The situation around the virus is aggravated by the fact that there is no vaccine for it. According to experts, the corresponding drugs will appear no earlier than in two to three years.
Routes of transmission of the virus
The Zika virus is transmitted by the Aedes aegypti mosquito, better known as the tiger mosquito. It is also a carrier of dengue and chikungunya viruses. A favorable environment for the reproduction of these insects is created, in particular, by garbage dumps and open water reservoirs. Aedes aegypti are present in most countries with tropical and subtropical climates.
Currently, employees of the Brazilian scientific Oswaldo Cruz Foundation (Fiocruz) are testing the hypothesis that other types of mosquitoes, for example, Culex, can be carriers of the Zika virus. This assumption is based on the fact that the fever epidemic was recorded in Micronesia, where Aedes aegypti does not live.
In addition, there is evidence that the virus can be transmitted from person to person during unprotected sex.
Transmission from mother to fetus is also possible. However, WHO emphasizes that “evidence of mother-to-child transmission of Zika during pregnancy or childbirth is limited.”
“Research is currently underway to gather more evidence regarding perinatal transmission and better understand how the virus affects infants.”
So far, there is “no evidence that Zika can be transmitted through breast milk.”
Symptoms
The Zika virus has the same symptoms as dengue and chikungunya fevers: high fever, headaches, muscle aches, weakness, skin rashes and conjunctivitis. In some cases, the disease is accompanied by nausea and vomiting, as well as stomach pain.
However, some experts point to the fact that Zika fever can occur without pronounced symptoms.
In this regard, it is very difficult to establish the exact number of cases: many patients, after contracting the virus, feel only mildly unwell and do not go to the doctor.
The disease lasts about a week (from two to seven days). The incubation period is from three to 12 days.
After recovery, the virus persists for more than two weeks in the seminal fluid.
Geography of distribution
WHO predicts that the Zika virus could spread widely in the Americas, affecting all countries except Canada and mainland Chile.
There are two main reasons for the rapid spread of the virus. The population of North and South America has not previously encountered Zika and therefore has no immunity against it. And secondly, the main vector, the Aedes aegypti mosquito, is present in all countries in the region except Canada and mainland Chile.
Continuation
At the same time, the WHO does not rule out that 3-4 million people in the world may become ill with Zika fever.
Against the backdrop of news coming from abroad, Russian President Vladimir Putin instructed Health Minister Veronika Skvortsova to prevent the spread of the virus in Russia, and also to develop antiviral drugs.
There is also some kind of nasty thing moving around from Latin America, also some kind of virus. Mosquitoes spread it, they, of course, will not fly across the ocean, but infected people can and do fly over
Russian President Vladimir Putin
In turn, the head of the Ministry of Health expressed confidence that this virus does not pose a threat to the citizens of the country.
How to protect yourself
According to Rospotrebnadzor, now the only effective way to combat Zika fever is to destroy the mosquitoes that carry the virus.
When visiting countries where Aedes aegypti mosquitoes live:
- use repellents;
- do not open windows that are not equipped with mosquito nets;
- wear long sleeves and pants (preferably light colors);
- try to avoid wetlands and crowded areas;
- If you feel unwell after returning from regions where Zika fever has been reported, contact your doctor immediately and report your visit to such countries.
To protect yourself from insects that carry the virus, it is advisable to use air conditioning indoors: according to some data, Aedes aegypti cannot tolerate temperatures below 16 degrees Celsius.
Rospotrebnadzor recommended that people be careful with water containers, since it is in them that mosquitoes that carry the virus actively reproduce. “In order to destroy possible breeding grounds for mosquitoes, containers in which even a small amount of water can accumulate (buckets, flower pots) should be washed and closed,” the department said.
The agency also published a list of 27 countries in North America, South America and the Asia-Pacific region where pregnant women are considered dangerous due to the Zika fever epidemic:
- Barbados,
- Bolivia,
- Brazil,
- Cape Verde,
- Colombia,
- Ecuador,
- Salvador,
- Fiji,
- French Guiana,
- Guadeloupe,
- Guatemala,
- Guyana,
- Haiti,
- Honduras,
- Maldives,
- Martinique,
- Mexico,
- New Caledonia,
- Panama,
- Paraguay,
- Puerto Rico,
- Saint Martin,
- Samoa,
- Solomon islands,
- Suriname,
- Thailand,
- Venezuela.
Source: https://tass.ru/obschestvo/2619455
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