No abstract

During 15 July to 4 October, 1999, rabies control programs were implemented with the objective being to contain the first three confirmed cases of raccoon rabies in Canada. The strategy, called point infection control (PIC) involved the use of three tactics: population reduction (PR), trap-vaccinate-release (TVR) and oral rabies vaccination with baits (ORV), to control the spread of raccoon rabies. A total of 1,202 raccoons (Procyon lotor) and 337 skunks (Mephitis mephitis) were captured and euthanized using 24,719 trap-nights in the three PR zones around the location of the three rabies cases, near Brockville, Ontario. That represented an 83% to 91% reduction in the raccoon populations in an approximate 225 km 2 area around the three rabies cases. Raccoon density in the PR zones declined from 5.1-7.1/km 2 to 0.6-1.1/km 2 following control. All tested specimens were negative for rabies by the fluorescent antibody test (FAT). In addition, 1,759 raccoons and 377 skunks were intramuscularly vaccinated against rabies and released using 27,956 trap-nights in an approximate 485 km 2 TVR zone implemented outside of the PR zones. A total of 856 cats from both PR and TVR areas were also captured, vaccinated and released. Cost for the three PIC operations was $363,000.00 Cdn or about $500.00 Cdn/ km 2 . To further contain the outbreak, about 81,300 baits containing Raboral V-RG oral rabies vaccine were aerially distributed on 8 and 27 September 1999, to create an 8 to 15 km wide buffer zone (1,200 km 2 area) of vaccinated raccoons immediately beyond the PR and TVR zones. This was the first time that V-RG was used in Canada to orally vaccinate free ranging raccoons against rabies. Baiting costs were $241,000.00 Cdn or about $200.00 Cdn/km 2 including post baiting assessment costs. As of 31 August, 2000, thirty-five additional cases (38 in total) of raccoon rabies have occurred in the control and vaccination zones. This number is far below the level of rabies prevalence in USA jurisdictions where raccoon rabies was epizootic. In the future, PIC methodologies will continue to be used in Ontario to contain isolated cases of raccoon rabies.

Several instances of emerging diseases in humans appear to be caused by the spillover of viruses endemic to bats, either directly or through other animal intermediaries. The objective of this study was to detect, identify and characterize viruses in bats in the province of Manitoba and other regions of Canada. Bats were sampled from three sources: live-trapped Myotis lucifugus from Manitoba, rabies-negative Eptesicus fuscus, M. lucifugus, M. yumanensis, M. septentrionalis, M. californicus, M. evotis, Lasionycteris (L.) noctivagans and Lasiurus (Las.) cinereus, provided by the Centre of Expertise for Rabies of the Canadian Food Inspection Agency (CFIA), and L. noctivagans, Las. cinereus and Las. borealis collected from a wind farm in Manitoba. We attempted to isolate viruses from fresh tissue samples taken from trapped bats in cultured cells of bat, primate, rodent, porcine, ovine and avian origin. We also screened bat tissues by PCR using primers designed to amplify nucleic acids from members of certain families of viruses. We detected RNA of a group 1 coronavirus from M. lucifugus (3 of 31 animals) and DNA from an asyet undescribed polyomavirus from female M. lucifugus (4 of 31 animals) and M. californicus (pooled tissues from two females).

A comprehensive phylogenetic analysis of the Lyssavirus genus, employing P gene sequences from 128 isolates recovered globally, is presented. While confirming prior suggestions of the genetic distinctness of the Australian bat lyssaviruses, these data also revealed a clear division within the rabies virus clade (Genotype 1) between globally distributed viruses circulating predominantly in canid species (subgroup 1-1), and American strains harbored by both chiropteran and terrestrial hosts (subgroup 1-2). Nucleotide substitution patterns within the P locus suggested differential selection operating along the length of the open reading frame (ORF) between rabies viruses of these two subgroups. Comparison of the deduced primary sequences of the encoded phosphoproteins of all isolates provided insights into the product's structural organization. Two conserved (CD1,2) and two variable (VD1,2) domains were evident; high variation in the VD2 region was reflected by differences in hydropathic profiles. Only two of five serine residues reported to function as phosphate acceptors in the P protein of the rabies challenge virus standard (CVS) strain were absolutely conserved; similarly, out of four internal methionines reported to direct internal translation initiation of the CVS strain to produce N-terminally truncated P proteins, only Met(20) was universally retained. In contrast, two sequence motifs, one believed to confer binding to the cytoplasmic dynein light chain LC8, and a lysine-rich sequence probably contributing to N protein binding, were conserved throughout the genus. Most rabies viruses of the carnivora (1-1) contain a potential C ORF in alternate frame to that of P, a feature limited or absent in most other isolates of the genus, an observation interpreted with consideration to the predicted course of lyssavirus evolution.

Canine rabies, responsible for most human rabies deaths, is a serious global public health concern. This zoonosis is entirely preventable, but by focusing solely upon rabies prevention in humans, this “incurable wound” persists at high costs. Although preventing human deaths through canine rabies elimination is feasible, dog rabies control is often neglected, because dogs are not considered typical economic commodities by the animal health sector. Here, we demonstrate that the responsibility of managing rabies falls upon multiple sectors, that a truly integrated approach is the key to rabies elimination, and that considerable progress has been made to this effect. Achievements include the construction of global rabies networks and organizational partnerships; development of road maps, operational toolkits, and a blueprint for rabies prevention and control; and opportunities for scaling up and replication of successful programs. Progress must continue towards overcoming the remaining challenges preventing the ultimate goal of rabies elimination.