The rabies situation in Eastern Europe.

An overview of the rabies situation in the 19 countries of Central and Eastern Europe covering more than 2.5 million km2 is presented. In 2005, 6,500 cases of rabies were registered in this region with 31% in domestic animals and 69% in wild animals. Rabies was found in a limited number of dogs in 10 countries, and sporadically in three countries with seven cases in bats. A similar situation existed in 2006. Rabies is very rare in humans: 2 cases were reported in Belarus in 2006. Around 40,000 people are treated yearly due to rabies exposure. The main vector and reservoir is the red fox (Vulpes vulpes), with a 50% incidence in positive findings. The raccoon dog (Nyctereutes procyonoides) is another significant vector, mainly in the Baltics. Oral vaccination is used in varying degrees in 10 countries, with promising results. Two countries are currently rabies free, and several others are close to being rabies-free. An unfavourable situation remains mainly in the Baltics and nearby eastern countries, and also in some Balkan regions. All countries studied have national reference laboratories, appropriate legislation, and rabies as a notifiable disease.

Rabies-free status of the Czech Republic after 15 years of oral vaccination.

Rabies in foxes was widespread in the Czech Republic after World War II, reaching its highest incidence in the 1980s. Applied control measures had only a limited effect and rabies incidence in wildlife continuously endangered both domestic animals and human beings. A significant improvement was noticed after the introduction of oral vaccination of foxes in 1989. The original manual distribution of vaccine baits has been replaced by aerial distribution, leading to the total elimination of rabies throughout the country. The last case of rabies was diagnosed in a fox in the district of Trutnov in April 2002. Since that time no case of rabies has been registered in the Czech Republic, and it therefore fulfils the requirements for the status of a 'rabies-free country'. Effective epidemiological surveillance and preventive oral vaccination of foxes will be necessary to maintain this status, especially in the endangered border regions.

Elimination of rabies in the Czech Republic.

Rabies in foxes was widespread in the territory of the Czech Republic after the Second World War. The first three cases of fox rabies appeared in North and South Bohemia in 1947. In the following year, a considerable increase in rabies incidence was reported and of the 146 cases, 106 (74 %) of the 117 wildlife cases were in foxes. Rabies in foxes and other wild animals was verified in many border Czech and Moravian districts. Sylvatic rabies was established in the Czech Republic and persisted there enzootically for many years as a continuing problem. The red fox (Vulpes vulpes) became the principal vector and reservoir. Averaging rabies cases over the long term, foxes account for about 90 % of all positive cases. The highest incidence of rabies was recorded in 1984, reaching 2,232 reported cases. Since then a continual decline in the number of cases has been visible, especially since 1992 when the positive effect of oral vaccination became evident.

Molecular epidemiology of rabies viruses in Europe.

Several different strains of classical rabies virus co-circulate in Europe. In order to investigate the roles of the host species and topography on the molecular epidemiology of these viruses, a 400 bp region of the nucleoprotein gene was sequenced and compared with more than 500 European virus isolates. Viruses from 21 European countries were represented including some unique panels of archived isolates from the former Republic of Yugoslavia, Estonia, the Czech Republic, Poland and Austria. Phylogenetic analysis of 198 unique sequences demonstrated numerous groups of viruses clustered at both geographical and host-species levels.

[The campaign against rabies--history and the present state]. / Boj proti vztekline--historie a soucasnost.

Rabies is one of the oldest known infectious diseases and with regard to its present prevalence it still remains an important zoonosis. In the submitted paper the author presents data on the historical development of scientific findings on rabies, the important part played by Louis Pasteur and his pupils, the development of the position as regards rabies in the Czech Republic in the past and present time and the role of different animal species. At present we can define in Europe five basic ecological biovariants of rabies associated with specific vector animal species. The role of a dominant vector is held in this country by the fox. Anti-infectious provisions are concentrated mainly on the oral immunization of foxes, preventive immunization of domestic animals and therapeutic and prophylactic provisions in man. In antirabies prophylaxis highly immunogenic and safe tissue vaccines are preferred.

[The role of small terrestrial mammals in the epidemiology of rabies]. / Uloha drobných zemních savcu v epidemiologii vztekliny.

The examination should help to elucidate the possibility of virus occurrence in free living small terrestrial rodents. The examination was oriented on the following: 1. Animals living in natural surroundings. 2. Rodents examined after injuring man. The examination was carried out by means of the direct immunofluorescent test and, partially, also by biological assay on suckling laboratory mice. In the first part of experiment, more than 10,000 small terrestrial mammals were entrapped, belonging to 16 species. In the second part of experiment, 1,969 rodents, belonging to 12 species, were examined after injuring humans. In these cases, a biological test was also carried out to demonstrate the occurrence of the virus. In neither of the above mentioned experiment the occurrence of rabies was proved.

[Vaccination of ferrets (Putorius furo) against rabies using a tissue vaccine]. / Vakcinace fretek (Putorius furo) proti vztekline tkánovou vakcínou.

The use of live tissue rabies vaccine from Vnukovo-32 strain produced by the Bioveta National Corporation at Ivanovice na Hané was tested on 15 ferrets (Putorius furo L. 1758). The 21st day after subcutaneous application of 3 ml of vaccine, the average titre of virus-neutralizing antibodies was 1 : 71.4, and after subcutaneous and intramuscular application of 1 ml of vaccine the average titre was 1:20.6 and 1 : 15.6, respectively. The challenge test was performed 52 weeks after vaccination: a dose of 10(5) MICLD50 of the street rabies virus was applied i. m. to the neck muscle. All the vaccinated animals survived. As indicated by the results of the trials, a good tolerance and full immunity of vaccinates to the infection with the street rabies virus was maintained for one year. 1 ml of vaccine diluted according to instructions and applied s. c. or i. m. was found to be sufficient.

[Annual testing of immunity in foxes after oral rabies immunization]. / Overení rocní imunity u lisek po orální imunizaci proti vztekline.

Ten young foxes were orally immunized with a "Rabies vaccine for oral immunization of foxes--LYSVULPEN por. a.u.v.," batch 69 10 93, commercially manufactured by the company Bioveta, s.r.o. at Ivanovice in Haná. The vaccine contained 1.8 x 10 of rabies vaccination virus, strain SAD-Bern, in a vaccination dose. Three foxes were used as control animals without vaccination. Blood samples were taken before the beginning of the experiment in all test foxes, and then in three-month intervals. The last blood samples were taken just before the beginning of a challenge experiment and two months after challenge in the foxes that survived. A challenge test was done in all foxes (vaccinated and nonvaccinated ones) a year after single oral immunization against rabies. Challenge virus was prepared from the salivary gland of a naturally infected fox living in the territory of the Czech Republic. Street virus was applied to each fox i.m. to a great depth to both masticatory muscles (musculus masseter) at a total dose of 10,000 MICLD50. The experimental animals were 60 days under observation. Tab. I shows the titers of virus-neutralizing rabies antibodies after oral immunization against rabies in all experimental foxes. Except fox no. 8, the formation of specific virus-neutralizing rabies antibodies was recorded in all animals after they had eaten vaccination baits. The antibodies were detected throughout the whole year of observation. Tab. II shows the results of challenge test. Out of the nine vaccinated foxes (fox no. 9 died before infection) only fox no. 8 died from rabies, the other treated foxes were protected from rabies (89% rate of protection). Tab. III presents the results of laboratory examination. Tetracycline was demonstrated in all treated foxes (a vaccination proof). Death due to rabies was demonstrated in control animals without vaccination and in fox no. 8. The results achieved in the Czech Republic for oral immunization of foxes against rabies with the vaccination strain SAD-Bern document very good efficacy of the vaccine manufactured by the company Bioveta, s.r.o., in Ivanovice in Haná since 1992. Oral immunization largely improved the infection situation in the Czech Republic. A total of 1,501 cases of rabies infection were recorded at the start of vaccination in 1989 while it was only 221 cases in 1994 (a decrease in then number of foci by 85%).

[Examination and incidence of rabies on the territory of the Czech Socialist Republic during 1969 - 1973]. / Vysetrení a výskyt vztekliny na uzemí CSR v letech 1969 az 1973

In the course of the years 1969 until 1973, 20 058 animals including 43 species were examined for rabies in the Czech Socialist Republic. In the mentioned period rabies was found out in 1002 cases. The lowest occurrence was in the year 1970 -- 110 cases, and the highest in the year 1972, when 267 positive cases of rabies were diagnosed. A majority of the positive findings in the five years' period occurred in freely living animals, of which 889 cases (88.7 p. c.) were foxes. In dogs and cats, rabies was found altogether in 53 cases, which amounts to 8.6 p. c. In the territory of the Czech Socialist Republic rabies occurs in its silvatic form with an occasional transmission to domestic animals.

[Pathologico-morphologic changes in the digestive system in rabid foxes]. / Patologicko-morfologické zmeny v trávicím ústrojí rabických lisek.

Pathologico-morphological changes in the digestive tract were investigated in fifty naturally infected common foxes (Vulpes vulpes crucigera). Nineteen animals were found to suffer from mild cachexia, 31 animals suffered from complete cachexia. Erosions were observed in the mucosa of oral cavities of 21 foxes. Traumatic injuries appeared in the teeth of 11 animals. One case of swollen and hyperaemic tongue was described; in three cases there occurred sialo-adenitis. A mild degree of inflammation was recorded in the gullet in three animals. Fifteen animals had empty stomachs, thirty-five animals had atypical food or foreign bodies in the stomach contents; simple hyperaemia was recorded 18 times, acute catarrhal gastritis 19 times and haemorrhagic gastritis was observed in two cases. Acute catarrhal enteritis was found in six cases, haemorrhagic enteritis in one case.

[Survival of rabies virus under external conditions]. / Prezívání viru vztekliny ve vnejsích podmínkách.

The survival of the street rabies virus in a 10% suspension, prepared from the salivary gland of a naturally infected fox, was studied under various conditions. A bioassay and titration on mice were used for the identification of the virus in different intervals. The heat inactivation of the virus in a suspension kept in a test tube at the temperatures of 20 degrees C and 37 degrees C was performed in two stages. The rapid reduction of the titre within 24 hours was followed by a slower decrease, reaching total inactivation after 96 hours at both temperatures. When the virus was tested by means of the contamination of various substrates (glass, metal sheet, plant leaf) with 0.1 ml of infection suspension in a thin layer, the longest survival of the virus was recorded at the temperature of 5 degrees C--144 hours. At the temperature of 20 to 21 degrees C the virus kept its activity on the glass and plant leaf for 24 hours and on the metal sheet for 48 hours although the applied drops looked like having dried. The temperature of 30 degrees C combined with intensive sunshine devitalized the virus within 1.5 hours, whereas without sunshine the virus still remained active, at the temperature of 30 degrees C, after 20 hours.

[Excretion of the rabies virus in foxes after experimental infection]. / Vylucování viru vztekliny u lisek po experimentální infekci.

Fourteen foxes (Vulpes vulpes crucigera) were experimentally infected with rabies. The excretion of the virus in saliva was subjected to qualitative study. Three different street strains isolated in the territory of the Czech Socialist Republic were used for the intramuscular infection at the doses of 50 or 5000 MICLD50. The presence of the virus in saliva was demonstrated in 12 animals (86%). Post-mortal examination revealed the virus in the salivary gland of 13 animals (93%). The virus started to be excreted in saliva maximally two days before the onset of the clinical signs of the disease and it lasted maximally six days. The affinity of the virus for the salivary gland was related to the strain used, and increased when a lower infection dose had been administered.

[What is next in antirabies immunization?]. / Jak dále v antirabické imunizaci?

The authors compare the geometrical means of titres of specific antirabic antibodies in a group of subjects immunized by the intradermal route with vaccine from a tissue culture of human diploid cell (Rabivac Behring, FRG) and in groups of subjects immunized by the subcutaneous route with the vaccine Vnukovo SAD-32 (USSR), using a short and long immunization pattern resp. The group with intradermal administration had higher geometrical mean values of antibody titres than the age-matched group immunized by the subcutaneous vaccine Vnukovo. The low mean titres and incidence of zero values of antirabic antibodies in age groups above 50 years is alarming.

[Intradermal method of vaccination with a human diploid cell tissue culture vaccine for preexposure antirabies immunization]. / Intradermální zpusob ockování vakcínou z tkánové kultury lidských diploidních bunek v preexpozicní antirabické imunizaci.

The authors provide evidence of seroconversion in 16 subjects (100%) following intradermal administration of antirabies vaccine from a tissue culture of human diploid cells [Rabivac, Behring, FRG] for the purpose of pre-exposure immunization. The immunomodulating preparation Levamisol [Decaris Richter, Hungary] did not influence the mean antibody titre during administration by the intradermal route.