Leucocytozoonosis in nestling bald eagles in Michigan and Minnesota.

Thirteen of 21 nestling bald eagles (Haliaeetus leucocephalus) examined for blood parasites in Michigan and Minnesota (USA) during June and July 1997 had patent infections of Leucocytozoon toddi. No other parasites were seen. The degree of parasitemia was light and varied from 1 to 2 on the Ashford Scale. Several of the infected nestlings appeared to have elevated levels of heterophils in their peripheral circulating blood. One of the infected nestlings also showed signs of severe anemia. We believe this is the first report of L. toddi in the bald eagle.     

Impact of the California lead ammunition ban on reducing lead exposure in golden eagles and turkey vultures

Predatory and scavenging birds may be exposed to high levels of lead when they ingest shot or bullet fragments embedded in the tissues of animals injured or killed with lead ammunition. Lead poisoning was a contributing factor in the decline of the endangered California condor population in the 1980s, and remains one of the primary factors threatening species recovery. In response to this threat, a ban on the use of lead ammunition for most hunting activities in the range of the condor in California was implemented in 2008. Monitoring of lead exposure in predatory and scavenging birds is essential for assessing the effectiveness of the lead ammunition ban in reducing lead exposure in these species. In this study, we assessed the effectiveness of the regulation in decreasing blood lead concentration in two avian sentinels, golden eagles and turkey vultures, within the condor range in California. We compared blood lead concentration in golden eagles and turkey vultures prior to the lead ammunition ban and one year following implementation of the ban. Lead exposure in both golden eagles and turkey vultures declined significantly post-ban. Our findings provide evidence that hunter compliance with lead ammunition regulations was sufficient to reduce lead exposure in predatory and scavenging birds at our study sites.     

Elemental and organochlorine residues in bald eagles from Adak Island,Alaska

Adak Island is a remote island in the Aleutian Island archipelago of Alaska (USA) and home to various military activities since World War II. To assess the contaminant burden of one of Adak Island's top predators, livers and kidneys were collected from 26 bald eagle (Haliaeetus leucocephalus) carcasses between 1993 and 1998 for elemental and organochlorine analyses. Mean cadmium, chromium, mercury, and selenium concentrations were consistent with levels observed in other avian studies and were below toxic thresholds. However, elevated concentrations of chromium and mercury in some individuals may warrant concern. Furthermore, although mean polychlorinated biphenyl and pp'-dichlorodiphenyldichloroethylene concentrations were below acute toxic thresholds, they were surprisingly high given Adak Island's remote location.     

Noninvasive assessment of seasonal hormone profile in captive bald eagles (Haliaeetus leucocephalus)

The hypothesis was to test whether a ratio of estrogen:androgen in eagle feces would reflect gonadal activity, and whether our procedure for noninvasive hormone analysis of fecal steroids could be applied to assess seasonal reproductive function in four captive bald eagles (Haliaeetus leucocephalus). Total immunoreactive excretory estrogens (E) and testosterone (T) were analyzed and compared as an E/T ratio from ad libitum monthly stool collections during the 1980–81 breeding season of birds maintained in an artificial insemination (AI) project. Since active male gonads are known to secrete a preponderance of androgens into the peripheral circulation and that renal clearance filters steroid metabolites into the urine, it was reasonable to assume that a lowered excretory E/T profile would mimic major changes in male seasonal steroidogenesis; analogously, active female gonads would result in an increased excretion of urinary estrogens, in turn reflected by a seasonal elevation of E/T ratios. A serial profile of excretory E/T ratio data for two male bald eagles approximated unity values except for a midseason low (x < 0.4) in February, one month prior to semen collections, followed by a significant end-of-breeding season rise in E/T values (x > 2.5, P < 0.01). The average E/T profile from data of two female eagles were two- to sixfold higher than males except for a significant mid-breeding season peak in E/T values during March (x > 13.5, P < 0.01). Despite the absence of nest building or egg production by either female, these preliminary observational data indicated seasonal patterns of gonadal activity in both female eagles that were synchronous with semen availability from adjacent males.     

Global approach to reducing lead exposure and poisoning

Lead poisoning is an important environmental disease that can have life-long adverse health effects. Most susceptible are children, and most commonly exposed are those who are poor and live in developing countries. Studies of children's blood-lead levels (BLLs) are showing cognitive impairment at increasingly lower BLLs. Lead is dangerous at all levels in children. The sources of lead exposure vary among and within countries depending on past and current uses. Sources of lead may be from historic contamination, recycling old lead products, or from manufacturing new products. In all countries that have banned leaded gasoline, average population BLLs have declined rapidly. In many developing countries where leaded gasoline is no longer used, many children and workers are exposed to fugitive emissions and mining wastes. Unexpected lead threats, such as improper disposal of electronics and children's toys contaminated with lead, continue to emerge. The only medical treatment available is chelation, which can save lives of persons with very high BLLs. However, chelating drugs are not always available in developing countries and have limited value in reducing the sequelae of chronic low dose lead exposure. Therefore, the best approach is to prevent exposure to lead. Because a key strategy for preventing lead poisoning is to identify and control or eliminate lead sources, this article highlights several major sources of lead poisoning worldwide. In addition, we recommend three primary prevention strategies for lead poisoning: identify sources, eliminate or control sources, and monitor environmental exposures and hazards.     

Genotoxic effects of occupational exposure to lead and cadmium

This study was designed to assess genotoxic damage in somatic cells of workers in a Polish battery plant after high-level occupational exposure to lead (Pb) and cadmium (Cd), by use of the following techniques: the micronucleus (MN) assay, combined with in situ fluorescence hybridization (FISH) with pan-centromeric probes, analysis of sister chromatid exchanges (SCEs), and the comet assay. Blood samples from 44 workers exposed to lead, 22 exposed to cadmium, and 52 unexposed persons were used for SCE and MN analysis with 5'-bromodeoxyuridine (BrdU) or cytokinesis block, respectively. In parallel, the comet assay was performed with blood samples from the same persons for detection of DNA damage, including single-strand breaks (SSB) and alkali-labile sites (ALS). In workers exposed mostly to lead, blood Pb concentrations ranged from 282 to 655 microg/l, while the range in the controls was from 17 to 180 microg/l. Cd concentration in lead-exposed workers fell in the same range as for the controls. In workers exposed mainly to cadmium, blood Cd levels varied from 5.4 to 30.8 microg/l, with respective values for controls within the range of 0.2-5.7 microg/l. Pb concentrations were similar as for the controls. The incidence of MN in peripheral lymphocytes from workers exposed to Pb and Cd was over twice as high as in the controls (P<0.01). Using a combination of conventional scoring of MN and FISH with pan-centromeric probes, we assessed that this increase may have been due to clastogenic as well as aneugenic effects. In Cd- and Pb-exposed workers, the frequency of SCEs as well as the incidence of leukocytes with DNA fragmentation in lymphocytes were slightly, but significantly increased ( P<0.05) as compared with controls. After a 3h incubation of the cells to allow for DNA repair, a clear decrease was found in the level of DNA damage in the controls as well as in the exposed workers. No significant influence of smoking on genotoxic damage could be detected in metal-exposed cohorts. Our findings indicate that lead and cadmium induce clastogenic as well as aneugenic effects in peripheral lymphocytes, indicating a potential health risk for working populations with significant exposures to these heavy metals.     

Influence of L-lysine and zinc administration during exposure to lead or lead and ethanol in rats

Influence of lysine and zinc administration on the lead-sensitive biochemical parameters and the accumulation of lead during exposure to lead or lead and ethanol was investigated in rats. The lead exposure inhibited blood δ-aminolevulinic acid dehydratase (ALAD) activity, increased blood zinc protoporphyrin (ZPP), urinary δ-aminolevulinic acid (ALA), serum glutamic oxalacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), blood and tissue lead levels, and decreased blood and hepatic glutahione (GSH) contents. Some of these effects were enhanced on coexposure to ethanol. The simultaneous administration of lysine and zinc reduced tissue accumulation of lead and most of the lead-induced biochemical alterations irrespective of exposure to lead alone or lead and ethanol. The depletion of endogenous calcium and magnesium owing to lead or ethanol exposure was also prevented by co-administration of lysine and zinc.     

Developmental exposure to lead and late life abnormalities of nervous system

Role of developmental exposure to environmental agents in altering the disease process is well known. Exposure to chemical agents at critical periods of development may cause some permanent changes in the functioning of various vital systems including the nervous system in the organisms. It is not surprising to see an extensive response due to exposure to chemical agents early in life as the organ systems are more vulnerable to chemical insults during developmental stages. In some cases the response to low level environmental insults may not be obvious until adult or old age. Results from several studies have shown such latency in response to the nervous system leading to neurodegeneration in old age. Studies conducted in murine and primate models provided ample evidence for the association of developmental exposure to low levels of heavy metal lead (Pb) and Alzheimer's disease-like pathology during senescence. It is not clear about the reasons behind such response; however, the contribution of epigenetic mechanisms could explain the role of early events in life in inducing the late life abnormalities of nervous system. It is possible that environmental agents epigenetically modulate the gene regulation to persist the response silent for a long period of time and to result pathological outcomes significantly later in life. This article will summarize the association of early life exposure to environmental agents and late-life abnormalities with an emphasis on developmental exposure to Pb and neurodegeneration in old age.     

Hygienic-toxicological aspects of exposure to lead. A critical review

This review on hygienic, toxicologic and ecologic aspects of environmental burden of lead deals with the following topics: occurrence, production and use of lead; metabolism of lead and experimental toxicology of lead; toxicity of lead to man; hygienic and ecologic aspects of lead pollution. Lead ore mining and processing, production of lead-acid batteries and combustion of gasoline containing tetraethyl-lead as an anti-knock ingredient constitute at present the most important sources of lead pollution. The last named source of lead pollution in urban atmosphere is most hazardous to human health. Attempts to reduce this health hazard include use of additive-free gasoline, or replacement of tetraethyl lead by other anti-knock agents, e. g. by tetraethylcopper. The experiments with the use of organic compounds of manganese have failed to succeed. The possibility of biological monitoring of occupational and nonoccupational exposures to lead is discussed in detail in this review.     

Survey for hemoparasites in imperial eagles (Aquila heliaca), steppe eagles (Aquila nipalensis), and white-tailed sea eagles (Haliaeetus albicilla) from Kazakhstan

Prevalence of hemoparasites has been investigated in many avian species throughout Europe and North America. Basic hematologic surveys are the first step toward evaluating whether host-parasite prevalences observed in North America and Europe occur elsewhere in the world. We collected blood smears from 94 nestling imperial eagles (Aquila heliaca), five nestling steppe eagles (Aquila nipalensis), and 14 nestling white-tailed sea eagles (Haliaeetus albicilla) at Naurzum Zapovednik (Naurzum National Nature Reserve) in Kazakhstan during the summers of 1999 and 2000. In 1999, six of 29 imperial eagles were infected with Lencocytozoon toddi. Five of 65 imperial eagles and one of 14 white-tailed sea eagle were infected with L. toddi in 2000. Furthermore, in 2000, one of 65 imperial eagles was infected with Haemoproteus sp. We found no parasites in steppe eagles in either year, and no bird had multiple-species infections. These data are important because few hematologic studies of these eagle species have been conducted.     

Amyoplasia congenita-like condition and maternal malathion exposure

This report concerns an amyoplasia-like condition in a case with maternal exposure to malathion during the 11th to 12th week of pregnancy. Malathion is an agent acting on the neuromuscular system. The possibility of a causal association is discussed.     

Hematocrit is related to age but not to nutritional condition in greater flamingo chicks

We measured the hematocrit from greater flamingo chicks Phoenicopterus roseus over 4 years to test whether this blood parameter was related to the nutritional condition of chicks, as there are controversial results on whether hematocrit may be used as an index of body condition. We also tested whether hematocrit increased with chick age, as there would be an age-related increase of oxygen demand due to exercising. We found no evidences that hematocrit was related neither to the nutritional nor to the body condition of chicks. Hematocrit increased with chick age, which may be related to the increased requirements of chicks for oxygen delivery during development.     

Rat renal carcinogenesis after chronic simultaneous exposure to lead acetate and N-nitrosodiethylamine

Chronic oral administration of lead acetate and/or N-nitrosodiethylamine to rats produces three different types of renal cell tumors composed of basophilic, chromophobic or oncocytic cells. The most frequent tumor, often visible macroscopically, is made up of basophilic cells and forms tubular, cystic, pseudo-papillary or solid structures; it may show considerable cellular atypia but does not metastasize or invade the surrounding parenchyma. Chromophobic and oncocytic tumors are rare and can only be detected with the microscope; they usually form cystic or solid structures. Basophilic and chromophobic tumors arise from specific segments of the proximal tubules, characteristic for each carcinogen: P2, P3C and P3M for lead acetate; P2 and P3C for N-nitrosodiethylamine. Karyomegalia in proximal tubule cells appears to be irrelevant in renal carcinogenesis. However, the appearance of basophilic and chromophobic cells in P2, P3C and P3M segments is considered to be an early change in tumor development. Oncocytic microadenomas originate from collecting ducts showing focal oncocytic transformation. Synergistic or inhibitory effects are not observed after chronic simultaneous administration of lead acetate and N-nitrosodiethylamine, although both carcinogens act in common on P2 and P3C proximal tubule segments.