Acceptance of candidate baits by domestic dogs for delivery of oral rabies vaccines.

Protocols for evaluating oral rabies vaccine baits for domestic dogs were field tested in central Mexico, after which dog-food manufacturers and suppliers to the pet-food industry were advised as to potential ingredients for use in prototype dog baits. Bait-preference trials in which confined dogs were used were then undertaken, followed by field tests of free-ranging farmer-owned dogs in three towns in the Nile River Delta region of Egypt. Both confined and free-ranging dogs showed strong preferences for certain baits or bait coatings (poultry, beef tallow, cheese, egg and a proprietary product). Fish-meal polymer baits, widely used for wildlife species, were less preferred. In Egypt, a commercial dog-food-meal bait coated with beef tallow and dry cheese, was consumed at a rate approaching that of a chicken-head bait. The percentage baits that were actually eaten after they had been offered to dogs, ranged from 71-96% for household dogs tested in Mexico, 65-91% for confined dogs (beagles and mixed breeds) tested in the United States, and 32-88% for farmer-owned dogs tested in Egypt.

A field evaluation in Mexico of four baits for oral rabies vaccination of dogs.

We evaluated four baits for the delivery of oral rabies vaccines to dogs. In a controlled study in a town in rural Mexico, 177 randomly selected dogs were assigned to receive one of four experimental baits (two of which were developed by the Denver Wildlife Research Center [DWRC]): one of two cylindrical polyurethane sponges with a corn meal coating (one fried in corn oil [DWRC-corn], the other in fish oil [DWRC-fish]), a fish-flavored polymer bait, or a wax bait. Each dog was also offered a commercial dog biscuit. We recorded whether or not the bait was completely consumed, and used the following measures to estimate the amount of oropharyngeal contact with each bait: total chewing time, presence of pieces of bait on the ground following administration, the total area of ground surrounding the location of ingestion that was covered with green dye contained in each bait, and condition of ampules that contained the dye. The dog biscuits were completely consumed significantly more often than the baits (155 of 176 [88%] for the biscuits versus 89 of 176 [50.5%] for the four baits; P less than 10(-6)), but were chewed for a significantly shorter time than the baits (mean time 34 sec for the biscuit versus 60-82 sec for the four baits: P less than 0.001). The ideal bait would probably combine the attractiveness of the commercial biscuit and the ability of the sponge baits to promote contact with the mucous membranes.

Prevention of canine rabies in rural Mexico: an epidemiologic study of vaccination campaigns.

We compared three vaccination strategies in three rural communities in Mexico to determine the factors associated with the success of vaccination programs in areas where canine rabies is poorly controlled. In town A, intensive publicity and community participation were used; owners were instructed to bring their dogs to temporary centralized clinics for vaccination. In town B, only brief precampaign publicity was used, followed by vaccination at a centralized site. Minimal publicity was also used in town C, but the vaccination campaign was conducted house to house. A total of 5,426 residents and 1,597 dogs were counted in the three towns (mean human:dog ratio 3.4:1). In Town A, 70.1% (472 of 673) of the dogs were vaccinated; the campaign required 40 person-minutes per dog. Significantly greater proportions were vaccinated in town B (262 of 318 [82.4%]; P less than 0.001) and town C (483 of 561 [86.1%]; P less than 0.00001); each of these latter campaigns required 10 person-minutes per dog. The following factors were positively associated (by multivariate analyses) with vaccination of individual dogs: non-intensive publicity, house-to-house vaccination, dogs owned by a single member of the household, and dogs acquired greater than 15 days after birth. Intensive publicity did not increase the overall success of the vaccination program; the efficiency of centralized versus and house-to-house vaccination was comparable.