Rabies is a preventable viral disease of mammals most often transmitted through the bite of a rabid animal. The vast majority of rabies cases reported in Yugoslavia each year occur in foxes. Domestic animals account for less than 10% of the reported rabies cases, with cats most often reported rabid, and occasionally in dogs, cattle, sheep and goats.
Rabies virus infects the central nervous system, causing fatal encephalitis and ultimately death. Early symptoms of rabies in humans are nonspecific, consisting of fever, headache, and general malaise. As the disease progresses, neurological symptoms appear and may include insomnia, anxiety, confusion, slight or partial paralysis, excitation, hallucinations, agitation, hyper salivation, difficulty swallowing, and hydrophobia. Death usually occurs within days of the onset of symptoms.
Public health importance of rabies
Over the last 100 years, rabies in the Yugoslavia has changed dramatically. More than 90% of all animal cases reported annually now occur in wildlife; In northern part of country urban rabies was eliminated before 1960, in Central Serbia at the end of seventies and in Kosovo and Metohija in early 1980. The principal rabies hosts today are foxes. The latest human deaths in the Yugoslavia were registered in 1980. on Kosovo i Metohija. Modern prophylaxis has proven with 100% successful. In Yugoslavia, animals bite about 10.000 persons annually. Only 10% of them are treated against rabies.
Post exposure prophylaxis in Yugoslavia is organized over the Net of Antirabic stations in Institutes of Public Health or Clinics for Infective Diseases across the country and it is free of coast for all of the patients. In last 10 years HRIG is produced in Yugoslavia, with high quality and good potency. Since 1990 the Institute for Blood Transfusion in Belgrade and Pasteur Institute in Novi Sad have been producing HRIG. Nowadays human rabies vaccine from cell culture is imported but in few last years we developed human rabies vaccine on BHK cell culture for human use. Now it is in clinical trails on human volunteers. We have good results in all with high antibodies titer and mild adverse reaction at the inoculation site.
The direct fluorescent antibody test (DFA) is most frequently used to routine diagnose of rabies. This test can be performed on brain tissue of animals suspected of being rabid. The rapid and accurate laboratory diagnosis of rabies infections in animals is essential for timely administration of postexposure prophylaxis. Within a few hours, a diagnostic laboratory can determine whether or not an animal is rabid and inform the responsible medical personnel. The laboratory results may save a patient from unnecessary physical and psychological trauma, if the animal is not rabid. All rabies laboratories in the Yugoslavia (3) perform this test on animals suspected of having rabies.
The DFA test is based on the principle that an animal infected by rabies virus will have rabies virus antigen present in its tissue. Because rabies is present in nervous tissue (and not blood like many other viruses) the ideal tissue to test for the presence of rabies antigen is brain. The most important part of a DFA test is flouresecently-labelled anti-rabies antibody. Pasteur Institute in Novi Sad produced fluorescent-labelled anti-rabies antibody on hamsters and goat. When labeled antibody is added to rabies-suspect brain tissue, it will bind to rabies antigen if it is present. Unbound antibody can be washed away and the areas where the antigen has bound antibody will appear as a bright fluorescent apple green color when viewed with a fluorescence microscope. If rabies virus is absent there will be no staining. The rabies antibody in the DFA test is primarily directed against the nucleoprotein (antigen) of the virus. Rabies virus replicates in the cytoplasm of cells, and infected cells may contain large round or oval inclusions containing collections of nucleoprotein (N) or smaller collections of antigen that appear as dust-like fluorescent particles if stained by the DFA procedure.