Effects of ultrasonic flea collars on Ctenocephalides felis on cats

Ultrasonic flea collars marketed by 2 companies were evaluated for their ability to reduce flea numbers on cats with experimentally induced flea (Ctenocephalides felis) infestations. The sound output of the collars was evaluated both before and after use to ensure that the collars were functional. Each brand was evaluated on 5 cats for a 7-day period. Collars generated peak frequencies of 40 kHz and 80 to 92 dB sound pressure level at 10 cm. An average of 98.6 and 97.4% of the fleas were still on the cats after treatment and control periods, respectively. The ultrasonic flea collars were ineffective in reducing flea numbers on these cats.     

Flea (Pulex simulans) infestation in captive giant anteaters (Myrmecophaga tridactyla).

A pair of captive adult giant anteaters (Myrmecophaga tridactyla) presented heavily infested with a flea species (Pulex simulans) commonly found on Virginia opossums (Didelphis virginiana) and raccoons (Procyon lotor) in the central United States. In this case, the flea was demonstrated to have completed its entire life cycle with the anteaters as the host. A single treatment of topical imidacloprid, coupled with removal and replacement of infested bedding, was rapidly effective at controlling the infestation and no adverse effects of the drug were noted. Control of the anteater infestation also removed the flea infestation of aardvarks in the same building.     

Transitions between blocked and zonal flows in a rotating annulus with topography

The mid-latitude atmosphere is dominated by westerly, nearly zonal flow. Occasionally, this flow is deflected poleward by blocking anticyclones that persist for 10 days or longer. Experiments in a rotating annulus used radial pumping to generate a zonal jet under the action of the Coriolis force. In the presence of two symmetric ridges at the bottom of the annulus, the resulting flows were nearly zonal at high forcing or blocked at low forcing. Intermittent switching between blocked and zonal patterns occurs because of the jet's interaction with the topography. These results shed further light on previous atmospheric observations and numerical simulations.