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Volume 26-02 |
International NotesWORLD SURVEY OF RABIES, 1997*The thirty-third world survey of rabies for the year 1997 is based on data received from 103 countries and territories out of 193 World Health Organization (WHO) Member States/Associate Members which were sent the questionnaire. In addition, other official sources were used, expanding its coverage to 169 countries and territories. The survey reports on five major topics: (1) rabies situation and trends for 1997
(2) rabies post-exposure treatments (3) rabies vaccine production and imports human vaccines animal vaccines (4) diagnostic techniques in medical and veterinary laboratories (5) rabies vaccine application to dogs and other animal species, including oral immunization. The survey also provided information on the main rabies epidemiologic patterns, the post-exposure treatment rate (per 100,000 population), diagnostic techniques most commonly used for rabies diagnosis, and countries where oral immunization of foxes and other carnivores is carried out. Rabies situation and trends, 1997 Human deaths Worldwide, the number of human rabies deaths is estimated to be between 35,000 and 50,000 annually. Africa: Most of the reported human deaths from rabies (96%) were diagnosed on clinical grounds only. The main source of exposure was dogs (40%). In 35% of reported cases, the source of exposure was unknown but thought to be related to a dog bite. Americas: A total of 114 rabies deaths were notified, 69 less than in 1996. The United States reported four human deaths caused by the exposure to bats. Asia: The highest incidence continued to be observed in Asia, with 33,008 reported human deaths. Most of them (an estimated 30,000) occurred in India. Rabies diagnosis was mainly made on clinical grounds only. Europe: With 13 deaths, Europe notified < 0.1% of all reported rabies mortality in the world. Most of these cases (10) were reported from the Russian Federation. The case notified in France followed exposure outside the country. Animal cases Africa: The total number of reported animal rabies cases was 2,344. In 72% of cases, the diagnosis was confirmed by a laboratory. The majority of the laboratory-confirmed cases occurred in dogs (57%), followed by ruminants (25%). Americas: With 16,486 animal rabies cases, the Americas reported 49% of the total number of cases in the world; 26% of all laboratory-confirmed cases were diagnosed in dogs. The United States notified 8,509 animal rabies cases, which is a indication of the level of active surveillance in this region as well as of the underreporting in other parts of the world. Rabies was mostly reported in wildlife in the United States, while dogs rabies prevailed in the Caribbean and South America. The number of cases diagnosed in bats was the highest compared to other continents. Most cases in bats were diagnosed in the United States, with 958 out of 961 cases for the whole of the Americas. Asia: The majority of rabies diagnoses in animals were laboratory-confirmed. The dog was the main species involved (90% of the total number of laboratory-confirmed animal rabies cases). The highest number of rabies cases was reported by the Philippines (with 1,966 laboratory-confirmed cases), followed by Thailand. Europe: A total number of 5,098 cases were reported. All reported animal cases were laboratory-confirmed. Wild animals remain the main rabies reservoir in Europe. The vast majority of rabies cases occurred in foxes (60%). Dogs were affected in 12% of cases, and ruminants accounted for 11% of the total cases reported, followed by cats (8%). Poland and the Russian Federation reported the highest number of animal rabies cases of all European countries. Rabies trends One of the countries that replied to the questionnaire for 1997 reported elimination of rabies (Italy). None of the countries or territories reported introduction of rabies. Trends are shown in Figure 1. According to the questionnaire, increase or decrease means at least a 10% variation against the number of rabies cases reported during the preceding year. Ten out of 17 countries in Europe reported a decrease of rabies cases. In the 54 countries and territories which reported on the epidemiologic pattern of the disease, dog rabies accounted for 57%, wildlife for 33% and bat rabies for 10%. Dogs rabies prevailed in Africa and Asia. Wildlife rabies was the main pattern in Europe and North America. Human rabies post-exposure treatment Dogs were the origin of exposure in 87% of the human post-exposure treatments administered in Africa, 97% in Asia, and 74% in Europe (where 8% of the treatments followed exposure to wildlife species). Rabies post-exposure treatment consisted mainly in the application of vaccine alone in Africa (82%), in Asia (88%), and in Europe (80%). In China, about 5 million people are estimated to be vaccinated annually. India estimated the annual number of post-exposure treatments at approximately 1 million, whereas Bangladesh reported around 60,000 post-exposure treatments per year. The designation employed and the presentation of material on this map do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city, or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Human vaccines According to replies from the 67 countries and territories, 13 produced human rabies vaccine in 1997. About 76% of all human rabies vaccine doses manufactured in these 13 countries were produced on cell culture. Seven countries produced only vaccines prepared on neural tissues. Six countries produced rabies vaccines on cell culture. All human vaccines produced in Europe are prepared on cell culture. Fifty-one countries reported importing human vaccines, 95% were of cell-culture origin, and 2% of neural tissue origin. Approximately 2% of the vaccines imported were manufactured on embryonating eggs. Animal vaccines Twenty-six (25%) out of 103 countries and territories reported producing animal rabies vaccines. Twelve countries (46%) produced vaccines prepared on cell culture, five countries (19%) on neural tissues, and 8% on embryonating eggs, with seven countries producing more than one type of vaccine; 99% of the total quantity of veterinary rabies vaccines were produced on cell culture, whereas 0.6% stemmed from neural tissue and < 0.1% were produced on embryonating eggs. Fifty-three countries and territories reported importing animal rabies vaccines. About 99% of these vaccines were prepared on cell culture. Diagnostic techniques used in medical and veterinary laboratories Thirty-four countries and territories provided information on the diagnostic used in medical laboratories and 67 on those used in veterinary laboratories. The fluorescent antibody test continued to be the technique most widely used to diagnose rabies in humans (32 out of 34 countries and territories) and in animals (61 out of 67). In 65% (22) of the 34 countries and territories, the laboratories responsible for human rabies diagnosis used the mouse inoculation test, 15% (five) histological techniques, and 24% (eight) other techniques. Many laboratories applied more one technique to confirm rabies cases. The tissue culture inoculation test was carried out in six countries, one country reported using an enzyme-linked immunosorbent assay and one a polymerase chain reaction test. Source: WHO Weekly Epidemiological Record, Vol 74, No 45, 1999. * Full document is available from: CDS Information
Resource Centre, World Health Organization, 1211 Geneva 27, Switzerland;
Fax: +41 22 791 42 85;
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