A Fluorescent Erythrocyte Test for Lead Poisoning in Waterfowl

Abstract

Forty-five mallards (Arlas platyrhynchos) and 12 Canada geese (Branta canadensis) were experimentally poisoned with lead shot. Blood samples collected from poisoned and unexposed birds were subjected to blue-ultraviolet light of approximately 400 m,t4 and examined microscopically for the presence of fluorescent erythrocytes. Some red fluorescence of erythrocytes was observed in all 64 blood samples drawn between 10 hours and 10 days postexposure from 27 of the poisoned mallards. Similarly, all 23 blood samples drawn between postexposure days 1 and 14, from the 12 poisoned Canada geese, contained unequivocally fluorescent erythrocytes. In general, after the first 3 to 9 days postexposure, the strength of the fluorescence progressively decreased, but still remained diagnostic at death for 19 of 20 mallards and for all 7 Canada geese that succumbed to lead poisoning. By com- parison, 19 mallards that had recovered from lead toxicosis, 20 unexposed mallards, and 11 of 12 unexposed geese had no erythrocytes that fluoresced. The fluorescence probably resulted from in- creased erythrocyte protoporphyrin caused by elevated blood lead concentrations. The fluorescent erythrocyte test is a quick, simple test for lead poisoning in waterfowl and appears to be as reliable as some conventional techniques previously used. In addition, blood from live birds can be tested for the presence of fluorescent erythrocytes. This test can therefore be used in conjunction with banding programs to investigate the incidence of lead intoxication in waterfowl populations.