Rabies prophylaxis

In humans, rabies still is a fatally evolving encephalomyelitis caused by a Rhabdovirus of the genus Lyssavirus. In general, the disease is contracted through a contact with an infected mammal. Taxonomically, different rabies and closely related rabies-like viruses can be distinguished. New molecular identification techniques can be utilized as epidemiological tools to study the geographic distribution and presence in different reservoirs of the viruses. Antigenic diversity and new insights in the mechanisms of the immune response can have serious implication in vaccine strategies. Virus detection for diagnostic and epidemiological purposes can be done by immunofluorescency, by inoculating murine neuroblastoma cells and by using molecular techniques. Rabies is a zoonosis with a worldwide distribution. In Belgium, the epizootic is present in the Southern part of the country. Fox vaccination campaigns contributed significantly to the eradication of the virus from its natural reservoir. The importance of the prophylactic and therapeutic use of the vaccine, the control of wildlife animal reservoir and stringent public health measures to combat rabies is discussed. Due to stringent control measures, no endogenous case of human rabies have been reported since 1922 in Belgium</p

Elimination of Fox Rabies from Belgium Using a Recombinant Vaccinia-Rabies Vaccine: An Update

To improve both safety and stability of the vaccines used in the field to vaccinate foxes against rabies by the oral route, a recombinant vaccinia virus, expressing the glycoprotein of rabies virus (VVTGgRAB) has been developed. VVTGgRAB innocuity was verified in target species and in domestic animals as well as in numerous wild animal species that could compete with the red fox in consuming vaccine baits in Europe. Oral immunization of foxes, by distributing VVTGgRAB vaccine-baits, was undertaken in the whole of the infected area of Belgium (10,000 km2). Five campaigns of fox vaccination covering the whole infected area were carried out from the autumn of 1989 until 1991. Each time, 150,000 vaccine-baits were dispersed by air at a mean density of 15 per km2. These campaigns induced a drastic decrease in the incidence of rabies and the elimination of the disease from 80% of the initial infected area. Regarding the geographical evolution of rabies in Belgium and in adjacent regions in neighbouring countries, new spatial strategies for bait dispersal were planned for 1992, 1993 and 1994: successive restricted campaigns were carried out along political borders only. These campaigns induced a new decrease of incidence; no rabid foxes could be detected in 1993 in spite of an improved epidemiological surveillance. In 1994, rabies was confirmed again in 13 foxes collected in a region situated close to the French border. These cases demonstrate the persistence of a focus of rabies on the border and justify further restricted campaigns of vaccination

Essai clinique d'innocuité et d'efficacité d'un vaccin antirabique inactivé et purifié à usage humain

Quatre cent soixante etudiants veterinaires en debut d'essai clinique (220 en Belgique et 240 en France) ont recu une primovaccination par voie intramusculaire (JO, J7 et J28) ainsi qu'un rappel apres 1 an avec trois lots industriels successifs d'un vaccin antirabique prepare sur cellules Vero et purifie par chromato­ graphie . Les resultats immunologiques tant apres primovaccination (J42) qu'apres rappel (J379) etaient supe­rieurs au seuil de protection theoriquement admis de 0,5Ul/ml. On n'a pas mis en evidence de difference si­gnificative entre les trois lots de vaccin utilises en terme de moyenne geometrique des titres en anticorps antirabiques neutralisants. Quant a l'innocuite de ce vaccin, les reactions locales et systemiques etaient en ge­neral legeres. Aucune reaction immediate severe n'a ete observee et aucun evenement indesirable grave n'a ete relie au vaccin. Les reactions locales sont le plus souvent des douleurs a l'endroit de !'injection: elles ap­paraissent dans 60% des cas en primovaccination et 53% des cas en rappel. Ces douleurs apparaissent le plus souvent dans les 24 heures apres vaccination et durent generalement 24 a 48 heures. L'incidence des autres reactions locales ne depasse jamais 9,8%. Les reactions systemiques sont le plus souvent legeres ou moderees; on y retrouve le plus souvent des troubles gastro-intestinaux et generaux. Le pourcentage de. su­ jets presentant au moins une reaction systemique variait de plus ou moins 20% en primovaccination a plus ou moins 15% lors du rappel. On n'a pas mis en evidence de difference significative dans la frequence d'appari­ tion des reactions locales et generales en fonction du lot, et cela quelle que soit la dose rec;ue. On peut conclure de maniere generale que la vaccination avec le vaccin antirabique prepare sur cellules Vero et purifie par chro­ matographie s'est revelee efficace et bien toleree

A Field Trial in Belgium to Control Fox Rabies by Oral Immunisation

Campaigns of fox vaccination against rabies were carried out in Belgium in September 1986 and June and September 1987. The SAD B19 attenuated strain of rabies virus was inserted into baits which were distributed over an area of 2100 km2 at a density of 11 baits/km2. As recommended by the World Health Organisation, the efficacy and the innocuity of the method were controlled in the field and in the laboratory. Samples of blood and brain and jaw were taken from foxes which were shot or found dead in the vaccination area, for the diagnosis of rabies, the titration of antirabies antibody and the detection of tetracycline marker. In rabid animals, the virus strain was characterised by immunofluorescence using monoclonal antibodies. In September 1987, the uptake of the baits had reached 72 per cent by 14 days after distribution. Several wild species competed with foxes in taking the baits. After the last campaign, tetracycline was found in 65 per cent of the healthy foxes collected and rabies virus neutralising antibodies were detected in 77 per cent of them. In 1987, the incidence of rabies decreased markedly in the vaccination area compared with the untreated areas. No vaccine virus was isolated either from rabid animals or from 228 small mammals trapped in the vaccination area