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Title: Spot-on Treatments of Diflubenzuron and Permethrin to Control a Guinea Pig Louse, Gliricola Porcelli (Phthiraptera: Gyropidae)

Author
item Reeves, Will
item Miller, Myrna

Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2009
Publication Date: 11/20/2009
Citation: Reeves, W.K., Miller, M.M. Spot-on Treatments of Diflubenzuron and Permethrin to Control a Guinea Pig Louse, Gliricola Porcelli (Phthiraptera: Gyropidae). Journal of Entomological Science. Vol. 44; 410-411.

Interpretive Summary: Guinea pigs are pets and laboratory animals. They can be infested by a chewing louse, which is fairly common in some animal rearing facilities, pet stores, and on wild guinea pigs. Lice are wingless ectoparasitic insects that can irritate and injure their hosts and transmit agents of diseases. Guinea pigs in a Missouri based breeding facility were reportedly suffering from continuous severe infestations of lice. We report on the insecticidal activity of 5% Dimilin mixed with 5% permethrin in an oil based solution, for the control of lice on naturally infested guinea pigs. We received naturally louse-infested guinea pigs, Louse infestations were measured on each animal by counting all lice in a known area. Animals were treated with 3 drops of Clean-UpTM. After 4 weeks a second louse count was made with a magnifying glass and lights. There were no lice found post treatment but untreated animals in the breeding facility were still infested. Based on our data a mixture of 5% Dimilin with 5% permethrin in an oil-based solution will control G. porcelli.

Technical Abstract: Guinea pigs (Cavia porcellus (L.)) (Rodentia: Caviidae) are pets and laboratory animals. They can be infested by a chewing louse, Gliricola porcelli (Schrank) (Phthiraptera: Gyropidae), which is fairly common in some animal rearing facilities, pet stores, and on wild guinea pigs. Infestation with G. porcelli can lead to scratching, partial alopecia, and scabs around the ears. In addition to irritating their hosts some lice of rodents have been associated with pathogens. Guinea pigs in a Missouri based breeding facility were reportedly suffering from continuous severe infestations of G. porcelli. Insecticides in the class of benzoylphenylureas such as diflubenzuron (Dimilin) and triflumuron are chitin synthesis inhibitors and are effective in controlling chewing lice. We report on the insecticidal activity of a spot-on insecticide containing 5% Dimilin mixed with 5% permethrin in an oil based solution, for the control of G. porcelli on naturally infested guinea pigs. We received guinea pigs from the breeding facility. The animals were naturally infested with G. porcelli and a fur mite Chirodiscoides caviae Hirst (Acari: Atopomelidae). Louse infestations were measured on each animal by counting all lice in a known area. Animals were treated with 0.15 ml of Clean-UpTM as a spot-on at the base of the neck and along the back-midline and animals remaining on the facility were untreated as controls. Animals were observed 24 h post application to check for irritation. After 4 weeks a second louse count was made. The average louse infestation for the pre-treatment guinea pigs was 3 lice/2cm2 with a range of 1 louse/2cm2 to 4 lice/2cm2. There were no lice found post treatment but untreated animals in the breeding facility were still infested. Based on our data a mixture of 5% Dimilin with 5% permethrin in an oil-based solution will control G. porcelli.