Facilitative ecological interactions between invasive species: Arundo donax stands as favorable habitat for cattle ticks (Acari: Ixodidae) along the U.S.-Mexico border.

The cattle tick, Rhipicephalus (Boophilus) spp. is a key vector of protozoa that cause bovine babesiosis. Largely eradicated from most of the United States, the cattle tick continues to infest south Texas, and recent outbreaks in this area may signal a resurgence of cattle tick populations despite current management efforts. An improved understanding of the dynamic ecology of cattle fever ticks along the U.S.-Mexico border is required to devise strategies for sustainable eradication efforts. Management areas of the cattle tick overlap considerably with dense, wide infestations of the non-native, invasive grass known as giant reed (Arundo donax L.). Here we show that stands of giant reed are associated with abiotic and biotic conditions that are favorable to tick survival, especially when compared with other nearby habitats (open pastures of buffelgrass (Pennisetum ciliare) and closed canopy native forests). Overhead canopies in giant reed stands and native riparian forests reduce daily high temperature, which was the best abiotic predictor of oviposition by engorged females. In sites where temperatures were extreme, specifically open grasslands, fewer females laid eggs and the resulting egg masses were smaller. Pitfall trap collections of ground dwelling arthropods suggest a low potential for natural suppression of tick populations in giant reed stands. The finding that A. donax infestations present environmental conditions that facilitate the survival and persistence of cattle ticks, as well or better than native riparian habitats and open grasslands, represents an alarming complication for cattle fever tick management in the United States.

Injuries and illnesses in working dogs used during the disaster response after the bombing in Oklahoma City.

OBJECTIVES: To determine characteristics of working dogs used during the disaster response after the bombing in Oklahoma City and risk factors for injuries and illnesses of those dogs, and to document recommendations for future disaster responses. DESIGN: Survey. STUDY POPULATION: Information for 74 working dogs used at the bombing site. PROCEDURES: Dog handlers were identified and asked to complete a questionnaire. Questions were asked about the training and use of each dog, use of paw protection, injuries and illnesses incurred, possible effects after completion of duty at Oklahoma City, and handler's experience. RESULTS: Data were obtained for all 74 dogs used at the site. Handlers of 69 of 74 (93%) dogs responded. The dogs had been extensively trained and were used 491 dog-days at the site, with 46 dogs used in search, 14 in patrol, 12 in explosive-detection duty, and 2 in search/patrol. Fifteen (22%) dogs became ill. Nineteen (28%) dogs incurred 20 injuries. Footpad injuries constituted 18 of the injuries. Only 16 of 69 (23%) dogs were provided with paw protection. Dogs were more likely to be injured when they were used in a search capacity, were used during the first 2 days after the bombing, were German Shepherd Dogs, or were older. CLINICAL IMPLICATIONS: Although working in a high-risk environment, injuries to dogs were few, and most were minor. Specific recommendations could facilitate use of dogs in disaster situations and improve safety for those dogs.

Metered dose inhalers III: Metaproterenol sulphate; particle size distribution and dose uniformity.

Three American products and one Canadian product were examined for content uniformity and particle size distribution. The results showed that not all products performed equally well. Some of the products exhibited high sprays early in the canister lifetime and all products demonstrated loss of prime. The particle size distributions were determined using the Andersen cascade impactor (USP Induction Port) and the fine particle fraction was determined using the twin impinger. The results showed that three of the four products had similar particle size distribution profiles. Both the Andersen cascade impactor and the twin impinger yielded the same trends in the amount of drug substance delivered to the fine particle fraction.