Selenium Toxicity in Breeding Ring-Necked Pheasants (Phasianus colchicus)

Environmental and occupational exposure of metals and female reproductive health

Untainted environment promotes health, but the last few decades experienced steep upsurge in environmental contaminants posing detrimental physiological impact. The responsible factors mainly include the exponential growth of human population, havoc rise in industrialization, poorly planned urbanization, and slapdash environment management. Environmental degradation can increase the likelihood of human exposure to heavy metals, resulting in health consequences such as reproductive problems. As a result, research into metal-induced causes of reproductive impairment at the genetic, epigenetic, and biochemical levels must be strengthened further. These metals impact upon the female reproduction at all strata of its regulation and functions, be it development, maturation, or endocrine functions, and are linked to an increase in the causes of infertility in women. Chronic exposures to the heavy metals may lead to breast cancer, endometriosis, endometrial cancer, menstrual disorders, and spontaneous abortions, as well as pre-term deliveries, stillbirths. For example, endometriosis, endometrial cancer, and spontaneous abortions are all caused by the metalloestrogen cadmium (Cd); lead (Pb) levels over a certain threshold can cause spontaneous abortion and have a teratogenic impact; toxic amounts of mercury (Hg) have an influence on the menstrual cycle, which can lead to infertility. Impact of environmental exposure to heavy metals on female fertility is therefore a well-known fact. Thus, the underlying mechanisms must be explained and periodically updated, given the growing evidence on the influence of increasing environmental heavy metal load on female fertility. The purpose of this review is to give a concise overview of how heavy metal affects female reproductive health.

Metals and female reproductive toxicity

Research into occupational exposure of metals and consequences of reproductive systems has made imperative scientific offerings in the preceding few decades. Early research works focused on possible effects on the reproductive functions rather than the complete reproductive health of the woman. Later, it was realized that metals, as reproductive toxins, may also induce hormonal changes affecting other facets of reproductive health such as the menstrual cycle, ovulation, and fertility. Concern is now shifting from considerations for the pregnant woman to the entire spectrum of occupational health threats and thus reproductive health among women.

Congestive Heart Failure in 6 African Grey Parrots (Psittacus e erithacus)

Six African grey parrots ( Psittacus e erithacus) were diagnosed with cardiomyopathy and congestive heart failure based on gross and microscopic findings. Ages ranged from 15 days to 8 years, and 5 of 6 parrots were either neonates or juveniles at the time of diagnosis. Two neonates and 2 juveniles came from the same breeding aviary; the 2 juveniles were born to the same breeding pair. The 2 other parrots were kept as pets. Clinical signs included distention of the coelomic cavity (4 of 6), rales (3 of 6), weakness (4 of 6), bradyarrhythmia (1 of 6), growth retardation (1 of 6), crop stasis (1 of 6), and regurgitation (1 of 6). Three parrots were euthanized and 3 died. Gross findings included cardiomegaly due to biventricular, right-, or left-sided cardiomyopathy (6 of 6); coelomic effusion (6 of 6); whitish or yellow foci in the liver (6 of 6); atrophy of the liver (particularly, the left lobe; 5 of 6); reddened or grey lungs (5 of 6); subcutaneous edema (2 of 6); hydropericardium (1 of 6); and bilateral thyroid gland enlargement (1 of 6). Relevant microscopic findings included passive hepatic congestion (6 of 6) and pulmonary congestion (2 of 6), lymphocytic thyroiditis (2 of 6), and diffuse thyroid follicular hyperplasia (2 of 6). Microscopically, the heart was unremarkable (2 of 6) or had mild lymphocytic myocarditis (2 of 6), mild multifocal cytoplasmic vacuolation of cardiomyocytes (2 of 6), mild lymphocytic myocardial (Purkinje cell) ganglioneuritis (1 of 6), and mild multifocal interstitial fibrosis and nuclear hypertrophy of cardiomyocytes (1 of 6). One parrot had concurrent proventricular dilatation disease (systemic ganglioneuritis). The cause of cardiomyopathy in these parrots was not determined.

Pet bird toxicity and related environmental concerns

Birds may be exposed to toxins through various sources in their everyday environment. Toxicity may occur through inhalation or oral or dermal exposures. Clinicians diagnose and treat these toxicities in an effort to correct the disease of the individual patient. Recognition of toxicity in the avian patient has further significance as it relates to the patient's environment, including the health of other animals, humans, and the ecosystem. While some toxicities, such as lead and zinc toxicosis, are well-documented in avian species, others are limited to anecdotal reports and extrapolation from other species. Continued research is needed in this area of avian medicine to expand our knowledge and improve our ability to diagnose and treat toxic conditions in birds.