Arsenic toxicosis in sheep: The first report from Iran

Abstract

Arsenic contamination of groundwater has been previously reported in Ghopuz, a village located in the Northwest of Iran. Samples were taken from consuming and irrigation water and plants of the region for chemical analysis. A seven-year old ewe, which had lived in and fed a lifelong at the same place, with clinical signs such as weakness, wasting and inappropriate integument was necropsied. Grossly, buccal erosion, stomatitis, cutaneous ulcers and serous atrophy of fat deposits were observed. Rumen contents, wool and several tissue samples were obtained for toxicological and histopathological examinations. Mean arsenic concentration in the spring water, irrigation water and grass/algae were 70.11, 48.74 and 141.85 ppb (µg/kg), respectively. Arsenic levels were 486.73, 247.94, 127.92, 125.97 and 231.24 ppb in wool, skin, rumen contents, liver and kidney, respectively. Microscopic study revealed hyperemia and heavy parasitic infestation of the abomasal wall. Hyperemia and regeneration of renal tubule epithelia were observed in kidneys and hyperkeratosis, suppurative deep dermatitis and paniculitis were found in skin. Periacinar fibrosis and a poorly differentiated cholangiocarcinoma were seen in liver. In pancreas, reduced cell density of islands of Langerhans was noticeable. In the central nervous system, perineuronal and perivascular edema, ischemic changes in gray matter neurons, and microcavitation of white matter were present. Our findings confirmed chronic arsenic toxicosis in small ruminants in this region. It can be concluded that long-term consumption of arsenic contamined water and forage may be associated with chronic arsenic poisoning in domestic animals and human beings, with consequent neoplastic disease and induction of diabetes in this region.

Keywords: arsenic; chronic poisoning; ghopuz; iran; small ruminant.

Figure 1

Chronic arsenicosis in a ewe: rumen mucosa is dark and leathery with erosions on pillar surface (arrow).

Figure 2

Chronic arsenicosis in a ewe: a solid whitish neoplastic mass, approximately 3.5 centimeters in diameter is seen at right side of parietal surface of liver (arrows).

Figure 3

Cut surface of the neoplastic mass is presented in Figure 2. Grossly, the mass was solid, white in color, firm in consistency with relatively homogenous cut surface.

Figure 4

A microscopic view of medulla oblongata in a ewe affected with chronic arsenicosis: perivascular edema (long arrows), ischemic change of large neurons (short arrows), satellitosis (arrow heads), and vacuolation of neuropil (stars) are noticed (H&E, 200×).

Figure 5

Microscopic view of endocrine pancreas in a ewe affected with chronic arsenicosis: a relatively normal islet of Langerhans (arrows) is observed (H&E, 400×).

Figure 6

Histopathological section of endocrine pancreas in a ewe affected with chronic arsenicosis: hypocellularity and evidence of pyknosis and regeneration of nuclei are seen in an affected islet of Langerhans (arrows) (H&E, 400×).

Figure 7

Microscopic view of tumor in liver of a ewe affected with chronic arsenicosis: the mass (arrows) consists of neoplastic cells arranged in acinar-like structures and diagnosed as cholangiocarcinoma (H&E, 40×).

Figure 8

Microscopic section of cholangiocarcinoma in liver of a ewe affected with chronic arsenicosis: neoplastic cells are arranged in acinar-like structures and tend to form lumen as bile ducts (arrows) (H&E, 400×).