Evaluation of two oral baiting systems for wild rodents.

Tetracycline hydrochloride (TC)-treated peanut butter or rodent chow baits were distributed during March 1990, on separate 0.53 ha sites in Oglethorpe County, Georgia (USA). Rodents were trapped on a control site prior to bait distribution and on two baited sites 6 days post-distribution. Cleaned skulls from euthanized mammals were grossly examined for TC fluorescence using an ultraviolet (UV) light. Mandibles were sectioned and examined for TC fluorescence using an ultraviolet light microscope. All 21 cotton rats (Sigmodon hispidus), four eastern harvest mice (Rithrodontomys humulis), and two golden mice (Ochrotomys nuttalli) captured on the control site were negative for TC fluorescence. On the peanut butter bait site, mandible sections from 29 of 32 (91%) cotton rats, three of three (100%) eastern harvest mice, two of three (66%) golden mice, zero of five (0%) white-footed mice (Peromyscus leucopus), one of three (33%) short-tailed shrews (Blarina brevicauda), and zero of two (0%) least shrews (Cryptotis parva) were positive for TC. Results from the rodent chow bait site indicated that 18 of 25 (72%) cotton rats, zero of three (0%) eastern harvest mice, two of seven (29%) golden mice, zero of four (0%) white-footed mice, and zero of four (0%) least shrews were positive for TC fluorescence in mandible sections. These results suggest that a large portion of a free-ranging small rodent population can be administered biological markers or vaccines using baits.

Field evaluation of baits and baiting strategies for delivering oral vaccine to mongooses in Antigua, West Indies.

A field study was conducted on Antigua, West Indies, to determine the feasibility of delivering an oral rabies vaccine or population control agent to free-ranging mongooses (Herpestes javanicus). Two biomarkers (tetracycline hydrochloride [THCL] and DuPont Oil Blue A dye) and two bait types (DuPont polymer fish meal and polyurethane foam) were used to bait three study sites. Four hundred polymer baits containing both biomarkers were distributed at 36 central point bait stations (11 baits/station) on an 80 ha study site (5 baits/ha); 69% of the mongoose population consumed one or more baits. Two thousand baits containing THCL and 400 baits containing DuPont dye were distributed on two additional 100 ha study sites (24 baits/ha). Polymer fish meal baits were used on the first site and polyurethane baits on the second site. Based on the presence of biomarkers in bone or soft tissue, 96 to 97% of the mongooses at both sites consumed at least one bait. We conclude that oral baiting of mongooses is a feasible method for delivery of vaccines for the control of rabies in this species.

Field evaluation of baits and baiting strategies for delivering oral vaccine to mongooses in Antigua, West Indies

A field of study was conducted on Antigua, West Indies to determine the feasibility of delivering an oral rabies vaccine or population control agent to free-ranging mongooses (Herpestes javanicua). Two biomarkers (tetracycline hydrochloride [THCL] and Dupoint Oil Blue A dye) and two bait types (Dupont polymer fish meal and polyurethane foam) were used to bait three study sites. Four hundred polymer baits containing both biomarkers were distributed at 36 central point bait stations (11 baits/station) on an 80 ha study site (5 baits/ha); 69 percent of the mongoose population consumed one or more baits. Two thousand baits containing THCL and 400 baits containing DuPont dye were distributed on two additional 100 ha study sites (24 baits/ha). Polymer fish meal baits were used on the first site and polyurethane baits on the second site. Based on the presence of biomarkers in bone or soft tissue, 96 to 97 percent of the mongooses at both sites consumed at least one bait. We conclude that oral baiting of mongooses is a feasible method for delivery of vaccines for the control of rabies in this species (AU)

Wildlife as hosts for ticks (Acari) in Antigua, West Indies.

A survey was conducted to determine the status of wild mammals and birds as hosts for Amblyomma variegatum (F.) and other tick species in Antigua. Surveys of wild mammals and birds were conducted periodically from September 1988 through May 1991. Wild mammals surveyed included the small Indian mongoose (Herpestes auropunctatus Hodgson), Norway rat (Rattus norvegicus Berkenhout), and house mouse (Mus musculus L.), but only mongooses were surveyed intensively. Larvae and nymphs of A. variegatum, larvae of Boophilus microplus (Canestrini), and larvae of Ornithodoros puertoricensis (Fox) were recovered. The mean prevalences of infestation of mongooses by A. variegatum larvae and nymphs were 4.7 and 1.3%, respectively; maximums were 16.1 and 5.0%, respectively. The mean prevalence of infestation of mongooses by B. microplus was 3.2%. O. puertoricensis is reported from Antigua for the first time. The mean prevalence of infestation of mongooses by O. puertoricensis larvae was 41.2%, but seasonal prevalences ranged from 27.8 to 55.0%. Of 610 birds representing 16 species, three Carib grackles (Quiscalus lugubris Swainson) were each infested with one larva of A. variegatum.

Potential role of cattle egrets, Bubulcus ibis (Ciconiformes: Ardeidae), in the dissemination of Amblyomma variegatum (Acari: Ixodidae) in the eastern Caribbean.

The potential role of cattle egrets, Bubulcus ibis (L.), in the dissemination of Amblyomma variegatum (F.) in the eastern Caribbean was evaluated. The status of cattle egrets as hosts for A. variegatum in Antigua was determined during seven survey periods between September 1988 and May 1991. The mean prevalences of infestation by larvae and nymphs were 2.3 and 0.5%, respectively. The mean intensity and relative density of infestation by larvae were 8.8 (SD = 9.80) and 0.2 (SD = 0.28), respectively. Cattle egrets examined in Guadeloupe during February-March 1991 were not infested but 5.9% were infested by larvae during June-July 1991. Interisland movement of cattle egrets was evaluated relative to emigration of birds captured and marked in Antigua and Guadeloupe. During this aspect of the study, 1,129 cattle egrets were captured, marked, and released. Of 195 sighting reports received, 56 were determined to be independent sightings. Emigration of cattle egrets included movement of birds marked in Antigua or Guadeloupe to 14 Caribbean islands and the Florida Keys. Interisland movement occurred in each of the discrete observation periods during the 3-yr study period. The rate of emigration per period ranged from 1.2 to 12.9%. That cattle egrets served as hosts for immature A. variegatum in the eastern Caribbean and moved between islands in the region demonstrates that these birds could serve as disseminators of the tick. Estimates of the numbers of infested cattle egrets emigrating from Antigua and Guadeloupe ranged from 0 to 0.24% of the current populations.

Evaluation of baits for oral rabies vaccination of mongooses: pilot field trials in Antigua, West Indies.

A field study was conducted on the island of Antigua, West Indies, to evaluate baits for delivering an oral rabies vaccine to the small Indian mongoose (Herpestes auropunctatus). Tracking tiles were used to determine that mongooses were nonselective and took both egg-flavored polyurethane baits and fish-flavored polymer baits containing several different food materials. A high proportion of baits were taken the day of placement with minimal disturbance by nontarget species. DuPont Oil Blue A dye was an effective short-term biomarker for use in baits; based on its subsequent detection in mongooses, some of the population had consumed and not cached or discarded baits. Central point baiting stations showed promise as an alternative delivery technique.

Evaluation of baits for oral rabies vaccination of mongooses: pilot field trials in Antigua, West Indies

A field study was conducted on the island of Antigua, West Indies, to evaluated baits for delivering an oral rabies vaccine to the small mongoose (Herpestes auropunctatus). Tracking tiles were used to determine that mongooses were nonselective and took both egg-flavored polyurethane baits and fish-flavored polymer baits containing several different food materials. A high proportion of baits were taken the day of placement with minimal disturbance by nontarget species. DuPont Oil Blue A dye was an effective short-term biomarker for use in baits;based on its subsequent detection in mongooses, some of the population had consumed and not cached or discarded baits. Central point baiting stations showed promise as an alternative delivery technique (AU)

A field trial to determine the feasibility of delivering oral vaccines to wild swine.

A field study was conducted on Ossabaw Island, Georgia (USA) to determine the feasibility of delivering oral vaccines to wild swine (Sus scrofa). Baits were made of polymerbound fish meal and contained a gelatin capsule as a potential vaccine chamber. Two biomarkers, iophenoxic acid and tetracycline, were incorporated into each bait, and soured chicken mash was used as an attractant. Baits (n = 1,980) were distributed in a grid pattern on a 405-ha test site and monitored for animal disturbance. Within 72 hr, 88% of 393 monitored baits were gone, and observations of track-beds surrounding 100 baits indicated that at least 52% were taken by wild swine. Subsequent testing of 80 wild swine for the biomarkers revealed that 95% of the animals had consumed bait. Track-bed observations indicated that raccoons (Procyon lotor) were the only non-target animal that frequently took baits. Biomarker analyses indicated 44% of 16 raccoons tested had eaten bait. It was concluded that oral vaccine delivery to wild swine should be considered as a feasible method of control or eradication of pseudorabies and/or swine brucellosis in wild swine if effective vaccines become available.