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Rabies in Belarus: epidemiological surveillance of the infection and questions concerning prevention and post-exposure measures for the population

 Rediger
 1 Published: 28.06.06 Updated: 28.06.2006 17:46:05

N.P. Mishaeva,  V.I. Botjakov, L. P. Titov
The Belarus Republican Scientific Research Institute of Epidemiology and Microbiology, Minsk

Over the past decade a sharp deterioration in the epizootic situation concerning rabies in the Republic of Belarus has been observed. During the period from 1996-2003, the number of rabies cases in animals rose 39.9 times. To fight the infection in the Republic of Belarus, a complex interdepartmental programme for 2001-2003 was developed with the participation of all involved ministries and departments. The number of cases among animals has been reduced 4.8 times in 2004 as a result of the implementation of this programme. Regardless, the situation is still strained, particularly on the border to the Baltic countries. The number of persons asking for post-exposure rabies measures has not declined.

Introduction

The Republic of Belarus is situated in the centre of Europe. The region borders the Russian Federation in the north and east, Ukraine in the south, Poland in the west and in the north-west with Lithuania and Latvia. The Republic has a territory of 207,600 km2 and more than 9.75 million inhabitants as of 01.01.2006. The Republic of Belarus has always been considered an endemic country for rabies, and the number of persons bitten by sick animals has been several times higher than in the adjacent countries both before and after World War II [1, 2]. In USSR as a whole, the number of persons asking for antirabies treatment was on average 30 per 100,000 whereas in Belarus the figure was 110 per 100,000, almost 4 times higher. The incidence in humans was also high, especially in the 1950s (52 cases of hydrophobia.) From 1951 to 2003, 135 persons died from rabies. The last case was registered in 2002.

Materials and methods

The data on the number of rabid animals were provided by the State Veterinary Centre and information about humans who received post-exposure prophylaxis after bites from rabid animals by the Republican Centre of Hygiene, Epidemiology and Public Health. The veterinary service has conducted continuous surveillance of the number of rabies cases among animals from after the war (1946). The brains of sick or suspect animals are examined in the veterinary laboratories. The rabies virus is detected by antibody immunofluorescence and, in cases of doubt, by viral neutralisation. Emergency reports on all cases of illness in animals are sent to the State Veterinary Centre.

Persons who have been bitten by a sick animal or an animal with unknown rabies status are given emergency medical attention (cleaning of the wound, administration of antirabies immunoglobulin and antirabies vaccine). Persons who have been in contact with rabid animals are contacted and receive the prescribed treatment with rabies vaccine. The regional health centres prepare quarterly reports on the number of persons bitten, the type of sick animals that have bitten humans and on post-exposure treatment measures for the population, and send the information to the Republican Centre of Hygiene, Epidemiology and Public Health, and to the Ministry of Health. The final reports are published on the internet (www.rchеph.by).

Results - Number of rabies cases among animals

According to data from the State Veterinary Centre and outbreaks of rabies among animals were registered in Belarus in 1971-1972, 1974-1977, 1979-1983 and 1985-1987. From 1988 to 1995, sporadic cases of illness in animals were registered. Since 1996 a new increase of rabies cases among animals has been observed with a peak in 2003.

Fig. 1 shows the development of the number of rabies cases in animals and the frequency of requests for post-exposure rabies treatment from 1991 to 2004.  The increase in the number of cases in animals started in 1996 and was registered at a maximum in 2003. Over this period, the number of cases rose 39.9 times and the infected territory increased significantly.  In 1996, 27 cases of illness were registered in 25 of 118 administrative regions (22.9%). In 2003, 1,077 cases of rabies in animals were registered in 112 administrative regions (94.9%); only 5 (5.1%) of the regions in the south and south-east of the republic were free of the infection.[2]. 

The number of cases in animals increased, especially during 2003. The number of cases among foxes (Vulpes vulpes Linnaeus, 1758) rose by 10.2 times (from 65 to 666 in total) over 5 years (1999-2003). During the same period, the number of cases in raccoon dogs (Nyctereutes procyonoides Gray, 1834) rose by 26.6 times (from 5 to 133 cases), an observation that is in accordance with the WHO data on the increased role of this animal in the epizootic of rabies in the European territory. An increase in the number of cases is seen among grey wolves (Canis lupus Linnaeus, 1758) by 3.7 to 7 times, domestic dogs by 8.4 times (from 17 to 143) and domestic cats by 4.1 times (from 29 to 120). The number of cases in farm animals rose by 4.7 times (from 15 to 70), particularly among cattle and horses (an increase of 6.3 times, from 10 to 63 cases).

Laboratory test results show a high infection rate for rabies virus among animals. Table 1 presents data from the Belarusian State Veterinary Centre's laboratory investigation of wild and domestic animals in 2003. Of the 1,029 tested animals, 977 (94.9%) were found to be positive. At the same time, 100% positive results were found when examining 120 cats, 6 horses, 24 raccoon dogs and 7 wolves.

Table 1. Results of laboratory confirmation of rabies among different types of animals  in 2003

In Belarus, the highest number of rabies cases in animals was registered in the north-western regions of the republic, on the border to Lithuania and Latvia. In Belarus 5.2 cases of rabies were registered per 1,000 km2, while in Latvia and Lithuania  the corresponding figures were 15.1 and 17.0 cases per 1,000 km2,  or 2.9 and 3.3 times higher, respectively (Fig. 2).

During 2001-2003, the Vitebsk region bordering Latvia had the highest number of cases of rabies among animals. Three powerful natural foci have been formed there; the north-west (Braslavskij-, Berkhnedvinskij-, Dokshitskij-, Polotskij- and Miorskij regions), the southern (Chashnikskij-, Beshenkovichskij- and Lepelskij regions) and the eastern (Shumilnskij-, Gorodokskij- and Vitebskij regions), where the number of rabid animals varied from 10-15 to 84-97 cases per region. In 2002, 304 cases of rabies in animals were registered in the region and in 2003, 425 cases (an increase of 1.4 times). Domestic animals (dogs, cats and farm animals) dominated and constituted 64.5% of all cases, while wild animals constituted 35.5% of all cases. The role of raccoon dogs increased sharply to 76.7% of all cases of rabies in wild animals. Sick animals (foxes, wolves, raccoon dogs etc.) came out of the woods and attacked humans and domestic animals [4]. Over the past four years (2000-2003) 848 rabies cases have been registered in Vitebesk region, 592 of the cases in wild and 256 in domestic animals.

To fight rabies, in 2001 the Ministry of Health in Belarus developed a three year interdepartmental programme with the participation of the ministries of agriculture and food-industry, municipal services, interior, forestry and environmental protection. The programme was approved by the Council of Ministers of the Republic (Resolution № 483 from 06.04.01 «On the complex programme for combating rabies for 2001-2003"). As a result the immunisation of wild animals using an oral vaccine has risen sharply in Belarus. Bait with rabies vaccine was spread over a territory of 4,171 km2 in 2001, 7,416.5 km2 in 2003 and –9,070.1 km2 in 2004. In all, bait with rabies vaccine was spread over a territory of 33,200 km2.  The bait was placed near the dens where the density of foxes and raccoon dogs was highest by veterinary personnel assisted by hunters and workers in the forest industry.

Intensive work was conducted to immunise domestic animals and capture stray dogs and cats (Table 2). During the programme against rabies (2001-2003), 1,007,558 domestic animals (913,677 dogs and 93,881 cats) were vaccinated with the rabies vaccine at the state’s cost. In comparison with 1999, the number of vaccinated dogs rose 1.4 times and cats 3.2 times in 2003. In 2004, more than 370,000 dogs and 60,000 cats were covered by vaccination, an increase of 1.6 and 4.3 times as compared to figures for 1999 [3]. 

Table 2. The number of vaccinated and captured stray animals (dogs, cats) in Belarus from 1999 to 2004.

The number of captureed stray animals rose; 55,257 dogs and cats were captured in 1999 and 63,398 in 2004, an increase of 1.5 times. As a result of  the measures taken, i.e. the rise in the number of wild and domestic animals that have been vaccinated and the capturing of stray animals, the number of cases of rabies in animals decreased by 4.8 times in 2004 when compared with 2003.

Frequency of requests for post-exposure medical attention from the population.

The number of requests for post-exposure rabies prophylaxis from the medical institutions in Belarus has always been high, even in 1993-1995 when only sporadic cases of rabies among animals were noted (Figure 1). At the beginning of the 21st century when there was a rise in the epizootic of rabies (2000-2003) and when the number of cases among animals increased by more than 75 times, the frequency of requests for medical attention increased only by 1.3-1.6 times.

The number of persons consulting medical institutions because of bites from domestic and wild animals is high. During 2001-2003, 50,842 persons suffered bites from domestic and farm animals and rodents. Dogs were resposible for 43,180 of the bites, 6546 cat bites, 986 from farm animals and 130 from other types of animals. Wild animals bites were reported by 2,409 persons  including bites from foxes (1863), wolves (48), raccoon dogs (345) and other types of wild animals(153).

Among the wild animals, the fox has the greatest contact with humans (1,863 cases over 3 years) both in rural areas (1,962 cases) as well as in towns (799 cases). A sharp rise in the number of humans bitten by raccoon dogs has been noted (Fig. 3.) Over the period investigated, 295 persons, including 184 inhabitants in large towns, suffered from bites from foxes and raccoon dogs.

An analysis of the reasons why persons seek medical services for post-exposure antirabies treatment shows that it is primarily because they have been bitten by dogs. More than 70% of those seeking medical attention due to bites every year have been bitten by dogs. Approximately 14% of them suffer from bites from sick cats, a little more than 2.0% from bites by farm animals and 4.5 % from bites by wild animals.

Discussion

The current epizootic and epidemiologic situation for rabies in Belarus is of concern. The number of persons who are in contact with rabid wild or domestic animals is increasing. The number of city-dwellers who are in contact with rabid wild and domestic animals during trips to dachas or garden plots during the summer in addition to tourists and temporary residents who visit the Republic of Belarus for excursions is growing. Medical and veterinary services face a considerable challenge  to decrease the number of rabies cases among animals and improve the post-exposure rabies treatment for the population. However, the experience from Belarus indicates that even in a very strained epizootic situation it is possible to decrease the number of cases in animals by increasing the oral immunisation coverage of wild animals, improving the vaccination coverage of all domestic animals, especially dogs, reducing the number of stray animals and providing relevant information to the population. Regardless, the fight against rabies in animals will only be successful when the measures are carried out according to plan. This applies not only in Belarus, but also in the adjacent countries where the number of cases of rabies among animals is high in order to exclude the import of infection over the administrative borders. Similar measures have resulted in the control of rabies in many countries of Western Europe.

Literature

1. Mishaeva, N. P., Votjakov, V. I., Titov, L. P.: Rabies and other lissavirus infections in humans. Issues on immune- and chemotherapy// Minsk, BIT “Khata” 2002, p 281
2. Mishaeva, N. P., Tsvirko, L. S., Pavljushenko. Rabies in Belarus. Problems of protecting the population // Minsk, BIT “Khata”, 2004, page 296.
3. Distribution of rabies in Europe. Country summaries of rabies cases, 2003 total //Rabies Bulletin Europe.– 2003.–Vol. 27.– N. 4. – P. 9.
4. Kurljukov, A. I. The epidemiological situation with Rabies in Vitebesk region //Dissertation and presentation at 58-th scientific congress Belarus State Medical Univeristy «Fundamental science and achievements in clinical medicine and pharmacy» - Vitebsk, 2003, pages 212-213.


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