Comparison of Trap and Equine Attraction to Mosquitoes.

Mosquitoes are pests of horses, but mosquito trap efficacy data, especially the ability of traps to protect horses, are lacking. Studies were conducted to investigate the comparative attraction between traps and horses, increase trap attraction by adding horse odors to the airstream of a trap, determine the spatial distribution of adult mosquitoes, estimate the numbers of mosquitoes feeding on horses, determine the relative attraction of horses to mosquitoes, and estimate the range of mosquitoes' attraction between two horses. When a horse and a mosquito trap were placed 3.5 m apart, there was a significant reduction in mosquitoes entering the trap. Adding horse odors to the airstream of a trap produced equivocal results because the horse providing the odors influenced the trap catches. Mosquitoes were not evenly distributed across the study site, which emphasized the importance of trap placement. Vacuuming mosquitoes from the horses in different seasons demonstrated that 324 and 359 mosquitoes per hour were feeding during the two studies. Separate analysis of data from the two horses vacuumed simultaneously revealed that one horse attracted twice as many mosquitoes as the other. This caused the results of a study to determine the attraction range of two horses moved from 3.5 to 20.4 m apart to be inconclusive.

Sweat osmolarity shows intra-animal regional variation in the horse.

BACKGROUND: Sweating is important in regulating body temperature but can be a source of loss of both fluids and electrolytes. Although the process has been studied in horses, the variation in sweat osmolarity across the body has not. OBJECTIVES: This work describes an investigation to determine if there is regional variation in the osmolarity of sweat across different anatomical regions of the horse. ANIMALS: Ten horses were used in the study and were animals either stabled for riding lessons or had livery on-site. METHODS: Sweat samples were collected from five regions on each horse following exercise and the osmolarity measurements were made using an Osmomat 030 (Gonotec, Berlin, Germany). Values were analysed by paired t-tests and analysis of variance. RESULTS: Samples from the back and ears had statistically (P < 0.05) lower osmolarity values than those seen for the neck and forelimb, with thigh values intermediate between the other two sets of values. CONCLUSIONS AND CLINICAL IMPORTANCE: Previous studies have used osmolarity values based on the sweat collected from the horse's back. The current work demonstrates that these values are probably an underestimation of electrolyte loss, which may have implications for the composition and administration of rehydration compounds.

Efficacy of Mechanical versus Non-Mechanical Sterile Preoperative Skin Preparation With Chlorhexidine Gluconate 4% Solution.

OBJECTIVE: To compare the efficacy of sterile preoperative skin antisepsis using either a 5-minute mechanical preparation or 5-minute non-mechanical preparation with chlorhexidine gluconate 4% solution. STUDY DESIGN: Matched design, ANOVA. ANIMALS: Healthy adult Thoroughbred horses (n = 30). METHODS: Each horse had both surgical preparation methods randomly assigned to identical sites on the left or right upper thigh. Prepared sites were sampled and cultured for bacteria after each preparation step. RESULTS: Mechanical and non-mechanical preparation techniques significantly reduced bacteria isolated from surface swab samples compared with samples taken from unprepared skin and after the preliminary rough prepared skin (P < 0.05). No difference in the number of skin-associated bacteria was detected between the mechanical and non-mechanical sterile preoperative preparation techniques (P = 0.77). Ten species of bacteria were identified by 16s PCR after final skin preparation. CONCLUSIONS: Pre-surgical skin preparation without repeated mechanical scrubbing using chlorhexidine gluconate 4% solution (total contact time, 225 seconds) is effective in reducing bacterial counts.

Seasonal abundance of stable flies and filth fly pupal parasitoids (Hymenoptera: Pteromalidae) at Florida equine facilities.

Beginning in November 2007 and continuing until December 2009, weekly stable fly, Stomoxys calcitrans (L.), surveillance was conducted at four equine facilities near Ocala, FL, by using alsynite sticky traps for adults and by searching immature developmental sites for pupae. Adult stable fly trap captures were highly variable throughout the year, ranging from 0 to 1,400 flies per trap per farm. The greatest adult stable fly activity was observed during the spring months of March and April, with weekly three-trap means of 121 and 136 flies per farm, respectively. The importance of cultural control measures was most apparent on the only farm with no reported insecticide use and the lowest stable fly trap captures, where an intense daily sanitation and composting program was conducted. A survey of on-site filth fly pupae revealed that 99.9% of all parasitoids recovered were Spalangia spp., consisting of Spalangia cameroni Perkins (56.5%), Spalangia nigroaenea Curtis (34.0%), Spalangia endius Walker (5.8%), and Spalangia nigra Latreille (3.7%). The implications of these findings are discussed.

Host blood meal identification by multiplex polymerase chain reaction for dispersal evidence of stable flies (Diptera:Muscidae) between livestock facilities.

A species-specific multiplex polymerase chain reaction targeting the cytochrome b gene of cattle, horses, humans, and dogs was developed to determine the blood meal sources of stable flies, Stomoxys calcitrans (L.), collected from Florida equine facilities. Of 595 presumptive blood-fed stable flies analyzed, successful host amplification was obtained in 350, for a field host-detection efficiency of 58.8%. The majority of analyzed stable flies had fed on cattle (64.6%), followed by horses (24.3%), humans (9.5%), and dogs (1.6%). A survey of animal-enclosed pastures occurring within 3 km of stable fly collection sites revealed that the nearest cattle were between 0.8 and 1.5 km from the four horse farm sampling sites. Cattle-feeding frequencies were greater on farms where cattle were located at distances of 0.8 km, suggesting that between farm differences in host-feeding frequency is related to the number of and distance from a particular host type. Time course evaluations of previously laboratory-fed stable flies demonstrated that host-detection efficiency with this system was 100, 50, and 0% when flies were evaluated at 16, 24, and 48 h postblood feeding, respectively. The results of this study suggest short-term stable fly dispersal of up to 1.5 km in a 48-h time period. The implications of these findings are discussed.

Assessing permethrin resistance in the stable fly (Diptera: Muscidae) in Florida by using laboratory selections and field evaluations.

Insecticide resistance in the stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae),has been demonstrated previously, but mostly with insecticides that are no longer used, such as the organochlorines. Resistance to commonly used pyrethroids has been evaluated twice, but only in the midwestern United States. Stable fly susceptibility to a commonly used pyrethroid, permethrin, was determined in Florida to assess the possibility of resistance development. Diagnostic concentration evaluations of three stable fly field strains demonstrated a maximum of 57 and 21% survival to permethrin residues of 3x and 10x the LC99 of a susceptible strain, respectively. Stable flies from an equine facility with no reported insecticide use demonstrated approximately 20% survival with a 3x diagnostic concentration. Despite a distance of 91-km between field collection sites, survival profiles of field-collected stable fly strains were similar. Although an established stable fly colony collected from a local dairy previously expressed low level resistance to permethrin residues, five generations of laboratory permethrin selection increased resistance 15-fold.