Evaluation of Mk-933 and Avermectin B1 For Control of Northern Fowl Mites, 19 79-1982

Abstract

Abstract In Vitro Tests: The inside surfaces of 12-cm pasteur pipettes were coated with 0, 0.001, 0.01, 0.1, 1 or 10 μg/cm/sq of MK-933 in 25 μl of acetone and air dried. The large end of the pipette was then filled with foam rubber and 10 adult northern fowl mites (NFM) were carefully vacuumed into each pipette and the small end was plugged with clay. Six pipettes of each treatment level were replicated 3 times. Pipettes were held at room temperature and checked for mortality at 1, 24, and 48 h. No NFM death could be attributed to MK-933 at any treatment level. In Vitro Tests: Mature White Leghorn hens were infested with NFM. After NFM populations had become well established, hens were individually treated either orally, by intramuscular (IM) injections, by subcutaneous (SO injections or by whole body sprays with specific formulations of MK-933 or Avermectin B1. Individual hens were given either single or multiple oral treatments or injections. MK-933 for oral treatment was dissolved in propylene glycol. Injectable formulations were suplied by Merck. Sprays were formulated from emulsifiable concentrates (EC) of AI in propylene glycol and Triton X-100 and each hen was treated with 30 ml of solution. NFM populations were visually estimated by the same observer at specified times posttreatment using the following mite index: 0, no mites; 1, 1-10 mites/hen; 2, 11-100 mites/hen; 3, 101-1000 mites/hen; 4, 1001-10,000 mites/hen; and 5, >10,000 mites/hen.