Copper oxide wire particles used to control Haemonchus infections: efficacy in giraffe (Giraffa camelopardalis) at Busch Gardens Tampa and potential mechanism of action

Gastrointestinal nematode (GIN) infections affect production systems and exotic hoofstock in zoos, particularly giraffe (Giraffa camelopardalis). Anthelmintic resistance (AR) prevalence is increasing in production systems and zoos. To combat the AR that compounds GIN problems, alternative control methods are used. One such alternative is copper oxide wire particles (COWP), which control the abomasal nematode Haemonchus contortus.

COWP was given to seven adult giraffe at Busch Gardens Tampa, at descending dosages: 25 g, 12.5 g, 6.3 g. Treatment administration time was determined by fecal egg count (FEC) being above 600 eggs per gram (EPG), and therefore varied with each animal. FEC following 25 g COWP treatment significantly (p < 0.05) decreased between Week 0 and Weeks 2-5. FEC following 12.5 g COWP treatment significantly (p < 0.05) decreased between Week 0 and Week 2. FEC following 6.3 g COWP treatment showed no reduction between Week 0 and all PT samples. A 25 g COWP treatment was an acceptable part of a GIN control program for treatment of Haemonchus in giraffe, a 12.5 g COWP treatment was minimally acceptable, and a 6.3 g COWP treatment was ineffective.

To determine the mechanism of action for COWP, 11 Suffolk lambs were abomasally fistulated and inoculated with H. contortus larvae. Abomasal contents, nematodes, feces, and blood were collected at 0, 12, 36, 60, and 84 hours post-treatment (HPT). pH was measured and nematodes were viewed using scanning (SEM) and transmission (TEM) electron microscopy and energy dispersive x-ray spectroscopy (EDS), and copper content analysis was performed. FEC and packed cell volume (PCV) were determined for each time period. pH was inconclusive. FEC decreased throughout the study and up to 33 days PT; no statistics were performed due to removal of nematodes. PCV had no substantial change, but the study time period was too short for a significant change. SEM showed no obvious changes between pre- and post-treatment. TEM showed cuticle damage present in PT samples. EDS showed copper present in 10 of 11 spots on PT samples. Copper content of nematodes was maximum at 60 HPT. Evidence suggests COWP has a direct effect on H. contortus.

Publish DateApril 19, 2021
Last UpdatedApril 19, 2021