Orthohantavirus

Globally, there are two major categories: Hantaviruses of the Old World and Hantaviruses of the New World .

Hemorrhagic Fever with Renal Syndrome

Hemorrhagic fever with renal syndrome (HFRS) is a group of clinically similar diseases caused by different types of hantaviruses in the Old World. Among them are: Hantaan orthohantavirus , Puumala orthohantavirus , Dobrava-Belgrade orthohantavirus and Khabarovsk orthohantavirus ^[5] . Mortality from this disease averages about 12%.

Hantavirus Cardiopulmonary Syndrome

Hantavirus Cardiopulmonary Syndrome is a similar group of clinically similar diseases that occur in the Americas. This virus group includes such species as Andes orthohantavirus , Laguna Negra orthohantavirus , Rio Segundo virus and Sin Nombre orthohantavirus ^[6] . The mortality rate of this disease averages up to 36% ^[7] , although in some cases it reached 60%.

The first major collision with hantaviruses is considered to be the outbreak of the disease, known as "Korean hemorrhagic fever." This happened during the Korean War of 1950-1953. Then, more than 3,000 soldiers of the United Nations organization experienced the effects of an unknown agent causing internal bleeding and renal dysfunction. The level of medicine at that time did not allow to determine the cause of the disease, so the virus remained unknown until 1976.

Dr. Lee and Johnson managed to isolate the etiological agent from an ordinary field mouse . The lung tissue of rodents caught showed a specific response to serum in patients with Korean hemorrhagic fever. Later, a comparison was made between the virus strains obtained from the mouse and sick people. In the same year, a study was shown of the relationship between outbreaks of a similar disease in the Soviet Union ^[5] . Currently, Korean hemorrhagic fever is known as hemorrhagic fever with renal syndrome and has been shown to be caused by Hantaan orthohantavirus .

The outbreak of diseases and the beginning of work on the study of hantaviruses in the United States occurred in 1993 in the Four Corners region of Colorado . A young and physically healthy representative of the Navajo people suddenly felt unwell, began to choke and, despite all the efforts of the doctors, died. The investigation showed that a few days before the incident, the bride of the young man also died from similar symptoms. In just a short period, there were five similar deaths. Researchers at the US Centers for Disease Control and Prevention used a new method for molecular analysis of viruses to determine the source. The virus turned out to be a new, still unknown type of hantaviruses. Subsequently, the virus was named Sin Nombre virus from the Spanish "nameless virus" ^[8] .

Views registered on ICTV

Species of the genus have little resemblance to other groups of viruses. The first classification of the genus Hantavirus was proposed in 1987 at a report in the International Committee on Virus Taxonomy (ICTV). In the future, the classification changed due to the expansion and correction of species composition. In 2017, in connection with the description of the order of the Bunyavirales, the genus was divided into the monotypic family Hantaviridae , changed its name to Orthohantavirus ^[9] and included 41 species in it ^[4] :

Species Awaiting Registration at ICTV

Every year the number of open hantaviruses is increasing. They are recognized either by typical strains of new species, or by varieties of other species. As of March 2017, the viruses that may be included in the genus Orthohantavirus are ^[4] :

Hantaviruses are roboviruses, that is, their distribution occurs through rodents . In addition, there are cases when the infection occurred after the bite of certain species of insectivorous bats ^[12] . Different types of viruses have close ties with their carriers, turning them into natural reservoirs . Now there is no exact answer, whether carriers of viruses influence their species formation. Some studies argue that hantaviruses adapt to a new carrier, thereby changing the structure of their RNA, forming new species ^{[13] [14] [15]} . Other studies show that the rate of mutation of RNA viruses corresponds to mutations in other viruses with a similar structure, from which it is concluded that the hypothesis of joint development is erroneous ^{[16] [17]} .

In most cases, the natural reservoir does not show any signs of disease from the hantavirus “native” by it ^[18] (an exception is the Puumala virus, which in some cases leads to the death of the carrier ^[19] ). When infected with alternative types of hantaviruses, adult rodents completely remove it from the body within 25-50 days, but for young individuals, infection is most often fatal ^[20] .

A study conducted in 2010 in Eurasia, North and South Americas, showed that all types of hantaviruses can be divided into 3 global groups of rodent subfamilies that are their carriers: mouse , field-popping , cotton-fowling ^[21] .

Most often, human infection with hantavirus occurs upon contact with rodents, or their metabolic products (urine, saliva, pulmonary secretions and droppings). Infection often occurs in warm and dry seasons, when people in large numbers go for walks in the forest. The virus enters the human body in various ways ^[22] :

• Inhalation of microparticles of the dung along with dust in the air, for example, when it penetrates into abandoned or preserved premises, including barns, garages and warehouses.
• Drinking urine-contaminated water and food.
• Direct contact with the carrier (rodent bite) is the lowest probability of transmitting the virus.

Transmission of the disease from person to person is not typical for hantoviruses. Nevertheless, such cases are found, but recorded only in Argentina ^[23] and Chile ^[24] .

Currently, only nucleocapsid protein is used for the serological diagnosis of hantavirus infections. In clinical practice, serodiagnosis in the form of an indirect enzyme-linked immunosorbent assay (ELISA) is widely used for the primary detection of infection and observation of it.

The study of hemorrhagic fever with renal syndrome began in Russia more than 70 years ago. The causative agents of this disease are Puumala , Huntaan , Seoul and Dobrava-Belgrade viruses. These include, in addition to pathogenic for humans, also viruses with unspecified epidemiological characteristics. In Russia, at least 8 hantavirus serotypes circulate among small mammals.

The most common natural focal infection in Russia is hantavirus infection in the form of hemorrhagic fever with renal syndrome. According to Rospotrebnadzor in 2006, 7197 cases of its people’s disease were registered in 48 subjects of the Russian Federation, the incidence rate was 5 cases per 100 thousand population, which is less by 1.4% than in 2005, but among children under fourteen years of age the incidence increased 17.3%, the total number of cases in this group is 195; The incidence of hantaviruses is more than 10-100 times greater than the incidence of tick-borne encephalitis , rabies and other common natural focal infections ^[25] .

At the moment, it is unknown the effective treatment for hantaviruses, except for the relief of symptoms, as well as support for the body's natural immunity. In the case of hantavirus cardiopulmonary syndrome, patients are immediately taken to the hospital and help restore respiratory function using liquid oxygen and mechanical ventilation ^[26] .

In the case of HFRS, continuous monitoring is established for the patient - taking into account the fluid injected and lost (to prevent dehydration ), Diet No. 4 is established , after which detoxification prophylaxis, antiviral therapy, antioxidant therapy, and prevention and treatment of infectious-toxic shock are carried out ^{[ 27]} .

The best way to prevent infection with hantaviruses is to control rodents, since human infection occurs through direct contact with bodily fluids and droppings. It also helps the destruction of rodent nests, the removal of all possible cracks and holes in the house, through which rodents can penetrate inside. Domestic predators such as cats and ferrets can also be a good help in preventing diseases.

During the years of the war in Korea in 1949-1953, the hantavirus infection clearly manifested itself, which made scientists immediately after the discovery of the hantaviruses begin work on the creation of a vaccine. In the early years, it used the traditional antiviral vaccines based on inactivated whole virion materials or attenuated strains, but due to difficulties in obtaining lysates of high titer hantaviruses, unconventional hemorrhagic fever vaccines with renal syndrome also used unconventional vaccines ^{[ what? ]} . The most tried and used is the killed Hantavax vaccine, developed by the Institute of Viral Diseases in South Korea. In China, four different vaccines are being analyzed. In Europe, a vaccine based on Puumela virus chimeric particles and recombinant protein based vaccines have been created at the Institute of Medical Virology in Germany ^{[28] [29]} . Since the 1990s, the company for the production of bacterial and viral drugs IPVE them. MP Chumakov is developing a vaccine based on the substrate of the brain tissue of Syrian hamsters ^[30] .