A Group of Experts of IPB Developed Diagnostic Kit from Egg Yolks for Rabies
Rabies virus is a neurotropic virus that causes rabies in humans and animals. Rabies transmission can occur through the saliva of animals and less commonly through contact with human saliva. Rabies virus, like many rhabdoviruses, has an extremely wide host range. In the wild it has been found infecting many mammalian species, while in the laboratory it has been found that birds can be infected, as well as cell cultures from mammals, birds, reptiles and insects. Rabies is an endemic fatal zoonotic disease, commonly transmitted to humans through contact (bites and scratches) with infected animals. Prevention and control of this fatal disease require a sensitive surveillance system to follow 'suspected' animal and human rabies cases thoroughly through the improved reporting system, which contains the history of exposure, clinical examinations, symptoms and laboratory results. Once symptoms of the disease develop, rabies is fatal to both animals and humans. Prevention of human rabies must be a community effort involving both veterinary and public health officials. WHO promotes activities for the control and elimination of dog rabies particularly in Asia and Africa. A number of WHO documents dealing with the various aspects of a comprehensive dog rabies control programme have been developed over time.
To respond such issues, a group of experts of the Faculty of Veterinary Medicine of Bogor Agricultural University (FKH IPB) implemented a study program on the preparation of rabies-specific yolk immunoglobulin (IgY) for the development of diagnostic kits. Members of the group were Suwarny Ruhi, Sri Murtini and Okti Nadia Poetri. The most widely used laboratory test for rabies diagnosis is the fluorescent antibody test (FAT), which is recommended by both WHO and OIE, as it is sensitive, specific and inexpensive. This “gold-standard” laboratory test is performed with fluorescent antibodies specific to the entire rabies virus or to the rabies ribonucleocapsid protein, labeled with a fluorochrome such as fluorescein isothiocyanate (FITC). The IgY extracts were used for preparing fluorescent conjugates which were used to detect rabies virus by FAT in infected cells culture.
Sri Murtini said efforts to control rabies could be done through vaccinations and the reduction of non-proprietary dogs. Rabies in humans is 100% preventable through prompt appropriate medical care. This major source of rabies in humans can be eliminated through ensuring adequate animal vaccination and control, educating those at risk, and enhancing access of those bitten to appropriate medical care. In some areas, rabies cases are on the rise in Indonesia. This condition certainly increases public awareness in efforts to control the disease. Rapid and accurate laboratory diagnosis of rabies in humans and other animals is essential for timely administration of post exposure 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, and financial burdens, if the animal is not rabid.
"The diagnosis of rabies disease in Indonesia has only been based on clinical symptoms and histopathological examination of brain preparations from animal suspects. Diagnose techniques for the detection of rabies virus should be continuously developed. Standard antibodies and antibodies are indispensable for rabies diagnosis. One of the alternatives developed is a diagnostic kit from chicken eggs, "he said.
He explained, that the methods of extraction of ribonucleocapsid and IgY are easy and feasible in producing a quality conjugate that can be used in rabies virus infection surveillance. Y immunoglobulin is an antibody protein found in chicken egg yolk. The presence of IgY in the yolk has the same analogy as the presence of IgG in milk. In chickens has been known to exist three classes of immunoglobulin analogous to mammalian immunoglobulin that is IgA, IgM and IgY. The chicken transfers the parent antibodies into the egg yolks. The parent antibody passively transferred by the mother to her child, serves as a defense system against foreign substances when the child's immune system is not perfect.
The results showed that anti-rabies antibodies could be detected in egg yolk during the second week after the first vaccination. The method of producing IgY antibody has some advantages over the production of antibodies from mammals. By this method there is no need to bleed the animals, it is easy to purify a large amount of antibody and it is feasible to produce a specific antibody with a small amount of antigen. Purification of IgY with NaCl yielded a concentration of 331 μg / ml and 184 μg / ml WSF technique. Based on these results, they concluded that chickens are an optimal host for the production of polyclonal antibodies with high titer. (Wied)
