Epidemiologic investigation of lead poisoning in trumpeter and tundra swans in Washington State, USA, 2000-2002.

An observational study was conducted to determine the proportionate mortality of wild trumpeter (Cygnus buccinator) and tundra (Cygnus columbianus columbianus) swans that died during the winters of 2000-02 in northwestern Washington State, USA. Among 400 swans necropsied, 81% were lead poisoned (302/365 trumpeter swans; 20/35 tundra swans). Mortality started in mid-November and peaked from late December through mid-February; swan mortality that was not associated with lead poisoning was uniformly lower throughout the winter months. Lead poisoning was 24 times more likely to be the cause of death in swans found in Whatcom County compared to swans found in other locations in northwestern Washington State (95% CI: 12.7, 47.0). Mortality attributable to lead poisoning was twice as likely in adults as in juveniles (95% CI: 1.0, 4.2). Aspergillosis was documented in 62 trumpeter and two tundra swans, including 37 swans in which mortality was caused by lead poisoning. Males were twice as likely as females to have aspergillosis (95% CI: 1.1, 3.8). Traumatic injuries were documented in 37 trumpeter and seven tundra swans, including seven trumpeter swans with concurrent lead poisoning. Dead swans found outside Whatcom County were four times more likely to have traumatic injuries compared to those found in Whatcom County (95% CI: 1.6, 10.0). Overall, lead-poisoned swans were significantly less likely to have concurrent aspergillosis or traumatic injuries. There was no apparent association between grit ingestion (total mass or mass categorized by size) and lead poisoning or number of lead shot. Not surprisingly, lead-poisoned swans were more likely to have one or more lead shot compared to swans that died from other causes (OR 294; 95% CI: 92, 1,005); lead-poisoned swans were also more likely to have one or more nontoxic shot compared to swans that were not poisoned (OR 63; 95% CI: 19, 318). The source(s) of shot are unknown but likely are in or near Whatcom County, Washington.

Assessment of plasma concentrations of doxycycline in budgerigars fed medicated seed or water.

OBJECTIVE: To determine whether plasma doxycycline concentrations considered effective for treatment of avian chlamydiosis could be safely established and maintained in budgerigars via administration of doxycycline in water or seed. DESIGN: Prospective study. ANIMALS: 68 healthy mature budgerigars. PROCEDURE: In 14-day trials, plasma doxycycline concentrations were measured in budgerigars provided with water containing 0, 50, 100, 200, or 400 mg of doxycycline hyclate/L or a hulled seed diet containing 0, 100, 200, or 400 mg of doxycycline hyclate/kg. On the basis of these results, birds were fed seed containing 300 mg of doxycycline/kg for 42 days, and a control group received unmedicated seed. Blood samples for plasma doxycycline analysis were collected either in the morning on treatment days 4, 7 14, 21, 28, 35, and 42 or in the afternoon on days 12, 26, and 40. Birds were observed daily. On days 14, 28, and 42, physical and plasma biochemical variables, PCV, and total solids concentration were measured; cloacal specimens were obtained for bacteriologic and fungal culture. RESULTS: During a 14-day period, treatment with water containing < or = 400 mg of doxycycline/L did not maintain plasma doxycycline concentrations of > or = 1 microg/mL, but seed containing 300 mg of doxycycline hyclate/kg maintained mean plasma doxycycline concentrations > 0.98 microg/mL for 42 days without notable adverse effects. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that hulled seed containing 300 mg of doxycycline hyclate/kg can safely establish and maintain plasma doxycycline concentrations that are considered adequate for treatment of chlamydiosis in adult nonbreeding budgerigars.