[Viruses and bats: interdisciplinary issues].

The virologists' attention to bats (Сhiroptera) changed in the late 20th century as the concept of emerging infections grew in popularity. Since the beginning of the COVID-19 pandemic, the number of publications on bat viruses has increased profoundly.History of the problem; biodiversity of Chiroptera and related viruses; medical and veterinary significance of some viral genera and subgenera (Lyssavirus, Henipavirus, Marburgvirus, Ebolavirus, Sarbecovirus, Merbecovirus), as well as problems of bat protection, are addressed in a concise form. Literature search was carried out in electronic databases, mainly for the period of 2000-2021. Publications in Russian that are poorly represented in English-language reviews are also included. The purpose of the review is to substantiate the importance of an interdisciplinary approach in the context of increased interest in the study of viral infections in bats. This review was written for researchers who have not previously dealt with this problem.Since the beginning of this century, the number of known virus species associated with bats has increased by an order of magnitude (>200). The families Rhabdoviridae, Coronaviridae, Paramyxoviridae are in the first ranks according to the number of findings, and the highest diversity of viruses has been established for the families Vespertilionidae, Pteropodidae, Molossidae. Interdisciplinary cooperation positively influences the efficiency, biological safety and practical significance of the ongoing research. The best results were achieved by multidisciplinary teams with good cross-training in several specialties. Many papers emphasize the need to balance health and conservation interests.The analysis of scientific publications indicates a change in research approaches in this area: from collecting individual facts within the framework of narrow specialties to a comprehensive assessment of new knowledge from ecological, evolutionary and socio-economic positions. Results of the research emphasize the need to maintain complex approaches addressing public health needs and environmental protection. The importance of bat-borne viral infections determines the necessity for correction and interdepartmental coordination of scientific research and surveillance of wildlife zoonoses in the Russian Federation.

Rabies in the Mongolian steppes.

Historically, rabies in Mongolia has been connected to the specific steppe and forest-steppe landscapes, known as the Mongolian steppes. The main reservoirs of the rabies virus (RABV) are the wolf, red fox and corsac fox. Fox rabies has been reported in Mongolia since the early 1960s. Eleven human rabies cases (0.4 per million inhabitants) were reported in Mongolia from 1994-2004. Wild animals predominated as a source of human infection: five people died following wolf bites, two were exposed to foxes, and four to dogs. From 1996-2004, 1,273 rabid animals were reported (about 140 per year). Cattle consisted of more than 80% of all reported cases. The Mongolian steppes continue into the Chita region of Russia and the Republics of Buryatia, Tyva and Altai. Four RABV isolates from the western part of Mongolia were sequenced and compared with available isolates from Russia, China and other countries. The isolates from Mongolia belonged to the "steppe" phylogenetic clade, which includes viruses circulating in vast territories, from Southeast Europe to Tyva, West Siberia and Kazakhstan. However, RABV isolates from Mongolian-type steppes in the east (Chita region, Russia) belong to the eastern group of arctic-like viruses.

Arctic and Arctic-like rabies viruses: distribution, phylogeny and evolutionary history.

Forty-one newly sequenced isolates of Arctic and Arctic-like rabies viruses, were genetically compared to each other and to those available from GenBank. Four phylogenetic lineages of Arctic viruses were identified. Arctic-1 viruses circulate in Ontario, Arctic-2 viruses circulate in Siberia and Alaska, Arctic-3 viruses circulate circumpolarly, and a newly described lineage Arctic-4 circulates locally in Alaska. The oldest available isolates from Siberia (between 1950 and 1960) belong to the Arctic-2 and Arctic-3 lineages and share 98.6-99.2% N gene identity with contemporary viruses. Two lineages of Arctic-like viruses were identified in southern Asia and the Middle East (Arctic-like-1) and eastern Asia (Arctic-like-2). A time-scaled tree demonstrates that the time of the most recent common ancestor (TMRCA) of Arctic and Arctic-like viruses is dated between 1255 and 1786. Evolution of the Arctic viruses has occurred through a northerly spread. The Arctic-like-2 lineage diverged first, whereas Arctic viruses share a TMRCA with Arctic-like-1 viruses.

The diversity of rabies virus in Russia demonstrated by anti-nucleocapsid monoclonal antibody application and limited gene sequencing.

A comparative analysis of anti-nucleocapsid monoclonal antibody (N-mAb) reaction profiles and DNA sequences was performed on 97 selected rabies virus (RABV) isolates from Russia and neighbouring states. A panel of 73 N-mAb from the Wistar Institute (Philadelphia, PA, USA), Veterinary Laboratories Agency (Weybridge, UK) and P-41 (Tübingen, Germany) was used. The sequence of a 400 bp fragment of the N gene was generated for all available isolates and a phylogenetic analysis of the fragment was carried out. The results of genetic and antigenic typing were in concordance, except for a few deviations. Three RABV variants with distinct antigenic patterns corresponded to well characterised genetic groups. The phylogenetic analysis also allowed the discrimination of RABVs with similar antigenic profiles originating from distant geographical locations in Russia and other states of the former Soviet Union. In some instances, more than one specific antigenic variant was detected within a phylogenetic group. A number of antigenic and genetic variants were associated with a specific host species (such as red fox, raccoon dog, wolf or polar fox) in different parts of Russia. A single, antigenically divergent, P-41-positive, rodent isolate from Siberia was described.

Bat rabies surveillance in the former Soviet Union.

More than 3,000 bats were examined for lyssaviruses in the territory of the Former Soviet Union (FSU) over the past 41 years (1964-2004). European bat lyssavirus type 1 (EBLV-1) was registered in the Ukraine and the European part of Russia. Lyssaviruses Aravan (ARAV, Kyrgyzstan, 1991), Khujand (KHUV, Tajikistan, 2001), Irkut (IRKV, Irkutsk region, 2002) and West Caucasian Bat virus (WCBV, Krasnodar region, 2002) were proposed as new lyssavirus genotypes. All reports on rabies virus (RABV; serotype/genotype 1) isolation from bats to date are questionable and must be corroborated. Two human rabies cases of bat origin were registered in the town of Voroshilovgrad, the Ukraine (1977) and the town of Belgorod, Russia (1985). The second case was confirmed as EBLV-1, whereas the first case was not identified. At least five lyssaviruses, different from RABV and from each other, were recognized in the territory of the FSU, and their potential significance for veterinary and public health should not be underestimated.

Molecular epidemiological study of Arctic rabies virus isolates from Greenland and comparison with isolates from throughout the Arctic and Baltic regions.

We report a molecular epidemiological study of rabies in Arctic countries by comparing a panel of novel Greenland isolates to a larger cohort of viral sequences from both Arctic and Baltic regions. Rabies virus isolates originating from wildlife (Arctic/red foxes, raccoon-dogs and reindeer), from domestic animals (dogs/cats) and from two human cases were investigated. The resulting 400 bp N-gene sequences were compared with isolates representing neighbouring Arctic or Baltic countries from North America, the former Soviet Union and Europe. Phylogenetic analysis demonstrated similarities between sequences from the Arctic and Arctic-like viruses, which were distinct from rabies isolates originating in the Baltic region of Europe, the Steppes in Russia and from North America. The Arctic-like group consist of isolates from India, Pakistan, southeast Siberia and Japan. The Arctic group was differentiated into two lineages, Arctic 1 and Arctic 2, with good bootstrap support. Arctic 1 is mainly comprised of Canadian isolates with a single fox isolate from Maine in the USA. Arctic 2 was further divided into sub-lineages: 2a/2b. Arctic 2a comprises isolates from the Arctic regions of Yakutia in northeast Siberia and Alaska. Arctic 2b isolates represent a biotype, which is dispersed throughout the Arctic region. The broad distribution of rabies in the Arctic regions including Greenland, Canada and Alaska provides evidence for the movement of rabies across borders.

[Zoonotic infections in the central and southern ulusy of the Republic of Sakha]. / Zoonoznye infektsii v tsentral'nykh i iuzhnykh ulusakh Respubliki Sakha.

The serological survey of humans, as well as agricultural animals and rodents, for the presence of zoonotic infections, was carried out. Local inhabitants were shown to have contacts with the causative agents of pseudotuberculosis, enteric yersiniosis, tularemia, leptospirosis, Q fever, tick-borne rickettsiosis, chlamydiosis, toxoplasmosis. The immune stratum with respect to enteric yersiniosis was found to have a greater index, while the immune strata with respect to chlamydiosis, Q fever, pseudotuberculosis had the least indices. However, the indices of immune strata perceptibly varied in individual regions. The highest occurrence of antibodies to all above-mentioned zoonotic infections was registered in Megino-Kangalasskii, Amga and Neriungrinskii ulusy [correction of regions]. The probable sources of leptospirosis, toxoplasmosis and Q fever were agricultural animals, while the probable sources of enteric yersiniosis and leptospirosis were rodents.

[Comparative data on the tick-borne encephalitis virus infectiousness of hungry and satiated taiga ticks (based on the results of an immunoenzyme analysis)]. / Sravnitel'nye dannye o zarazhennosti virusom kleshchevogo éntsefalita golodnykh i pitavshikhsia taezhnykh kleshchei (po rezul'tatam immunofermentnogo analiza).

The results of individual investigation of 25,500 Ixodes persulcatus ticks from east Siberia are presented. The ticks were collected from grass, men, and animals before their sticking and after feeding at different intervals. The quantity of positive specimens was 6-11 times higher among the fed ticks hungry ones and averaged 10.36 and 1.85%, respectively, at the first stage due to the higher aggression of the infected females at the first stage and due to viral replication when the tick had feed and its better recognition as the titers increased. The proportion of ticks having high levels of tick-borne encephalitis virus antigen among the fed ticks was also considerably higher. The content of virus antigen increased in proportion with the duration of feeding. There is a moderate correlation (r = 0.59) of the infection index of hungry and fed ticks in different years and in various areas. The findings suggest that the fed ticks should be used as an additional marker for the features of tick-borne encephalitis virus circulation.

[New data on the spread of P-41-positive strains of the rabies virus in arctic and extra-arctic regions]. / Novye dannye o rasprostranenii P-41 polozhitel'nykh shtammov rabicheskogo virusa v arkticheskom i vnearkticheskom regionakh.

271 strains of rabies virus, isolated in different regions of the former USSR, were studied with the use of monoclonal antibodies P-41 (Germany). All strains isolated in the arctic regions, as well as some of the strains isolated in nonarctic regions situated 300-1700 km south of the polar circle (the Baltic countries, Central Yakutia, the eastern part of the Transbaikal region), gave positive reaction with these antibodies. Cases of hydrophobia caused by virus with the 41 (+) marker were described. Information on the spread such strains in other parts of the world is presented.

[Experimental lyssavirus infection in chiropters]. / Eksperimental'naia lissavirusnaia infektsiia u rukokrylykh.

Insectivorous bats, Pipistrellus pipistrellus in the active stage and hibernation were inoculated with bat unclassified Lyssavirus Aravan and Lyssavirus serotypes 1 and 4. The influence of hibernation on the duration of the incubation period and the distribution of viruses in extraneural tissues was demonstrated. Clinical symptoms of the diseases caused by different strains are described.

[A lyssavirus with an unusual antigenic structure isolated from a bat in southern Kyrgyzstan]. / Lissavirus s neobychnoi antigennoi strukturoi, vydelennoi ot letuchei myshi na iuge Kyrgyzstana.

Examination of 191 specimens of Chiroptera in Osh Province of Kyrgyzstan yielded 1 strain of lyssavirus from Myotis blythi, the isolate not belonging to serotype 1. The virus was designated Aravan by the area of its isolation. Its antigenic structure was studied using antinucleocapsid monoclonal antibodies of the Wistar Institute (Philadelphia, ISA) and Central Veterinary Laboratory of Great Britain (Waybridge, Great Britain). The paper presents its antigenic profile, brief characteristics of similarity and differences of the Aravan strain and known lyssavirus serotypes.

[The experimental infection of bats with lyssavirus serotypes 1 and 4]. / Eksperimental'noe zarazhenie letuchikh myshei lissavirusami serotipov 1 i 4.

The results of intramuscular inoculation of 111 bats (Myotis daubentoni, Myotis brandtii) with three strains of Lyssaviruses--Yuli, Stade, and 1150 are presented. Bats were found to have low susceptibility, especially to strains of serotype 4. After infection with serotype 4 viruses, fewer bats died but within shorter periods than after infection with serotype 1. After inoculation with strain 1150, 60% of bats yielded virus, whereas only 9-24% did after inoculation with type 4 strains. The survival time after inoculation was 32.2 and 19.0 days, respectively. Manifestations of the disease, virus distribution in viscera, and the results of examinations of specimens from bats by express methods are described.

[The results of using direct solid-phase immunoenzyme analysis for assessing the specific activity of rabies vaccines]. / Rezul'taty ispol'zovaniia priamogo tverdofaznogo immunofermentnogo analiza dlia otsenki spetsificheskoi aktivnosti antirabicheskikh vaktsin.

The effectiveness of the solid-phase enzyme immunoassay (EIA) in the determination of the specific activity of rabies vaccines is evaluated in comparison with that of the protective test in mice. Inactivated tissue-culture, concentrated tissue-culture and purified cerebral tissue vaccines for human use were studied. The methods for performing two EIA variants and evaluating the results are described. The average level of correlation between the results of EIA and the protective test for vaccines of different groups was revealed (0.546), the highest correlation index being obtained for tissue-culture vaccines: 0.753. On the basis of the data obtained in this study the expediency of using EIA for the determination of the specific activity of rabies vaccines has been substantiated.

[The antigenic characteristics of field strains of the rabies virus from different districts of the USSR studied using antinucleocapsid monoclonal antibodies]. / Antigennaia kharakteristika polevykh shtammov virusa beshenstva iz razlichnykh raionov SSSR s pomoshch'iu antinukleokapsidnykh monoklonal'nykh antitel.

98 rabies virus strains isolated from different species of wild and domestic animals have been studied by means of 36 monoclonal antibodies obtained from the Wistar Institute (USA) and 3--of the Federal Research Center on Viral Diseases of Animals (FRG). The antigenic variants determined in this study have been analyzed in comparison with the data obtained in other regions of the world, thus establishing the spread of these variants and their relationship with different species of animals.

Rabies-related Yuli virus; identification with a panel of monoclonal antibodies.

Yuli virus was isolated by intracerebral (i.c.) inoculation of suckling mice with a 10% brain suspension from 11-year-old patient who died under signs of atypical hydrophobia after a bat bite into lower lip. Identification with a panel of monoclonal antibodies (MoAb) to nucleocapsid protein (NP) confirmed that Yuli virus belongs to Lyssavirus genus, as an antigenic variant of the European Duvenhage virus.

[Detection of rabies virus antibodies in human blood serum by an immunoenzyme method]. / Obnaruzhenie antitel k virusu beshenstva v syvorotke krovi liudei s pomoshch'iu immunofermentnogo metoda.

In a coded experiment on rabies virus antibody detection in the blood sera of humans immunized with rabies vaccines, coincidence of the results of indirect ELISA, neutralization test and radial hemolysis test (RHT) was observed in 83% and 90% of the cases. The correlation coefficient of antibody titres in ELISA and NT was r = +0.75, ELISA and RHT r = +0.81. Instances of discrepancy of the results were observed with sera of low titres, no more than 1:50 by neutralization test.

Experimental rabies in hibernator rodents.

Experiments carried out in different seasons with different strains of rabies virus have shown that hibernation prolonged the incubation period in sousliks (Citellus major Pall.). Mean survival of the animals infected during the active period was 32 days, while during hibernation it was 147.3 days (P less than 0.05), in some cases up to 251 days. The virus was isolated from and/or detected by fluorescent antibody test in 50% of cases in the brown fat and in some cases in the salivary glands and visceral organs. The brown fat biopsy allowed to detect the virus not earlier than 6 days before death. We propose to use heterothermal rodents for the study of mechanism of rabies virus persistence and suggest that these animals might represent a natural reservoir for rabies.