Chronic eperythrozoonosis in an adult ewe

Abstract

April 25, and the ewe was treated with two doses of 20 mg/kg oxytetracycline (Engemycin 10 per cent) for suspected bacterial pneumonia. The illthrift and harsh lung sounds initially improved, but the ewe developed more severe anaemia; the organisms reappeared in blood smears, and the pneumonia recrudesced. The ewe was euthanased on June 18, 2002, and examined postmortem.Grossly, the ewe's carcase was pale and emaciated. There was 200 ml of clear, pale yellow fluid in the peritoneal cavity. Gelatinous oedema was evident in the mediastinal, mesenteric and perirenal tissues. Haemal nodes in the mesentery and sublumbar tissue were enlarged, with dimensions up to 10 mm x 5 mm x 5 mm. There was well demarcated, greybrown consolidation in the cranioventral portions of the left and right lungs, and brown, malodorous fluid exuded from cut surfaces.On histological examination, the lymphoid tissue of the haemal nodes was hyperplastic (Fig 2b), whereas there was little development of lymphoid follicles in the splenic white pulp or the cortices of the mesenteric and mediastinal lymph nodes. The medullae of the lymph nodes were oedematous, with a diffuse increase in polymorphonuclear leucocytes. Haemosiderosis was evident in Küpffer cells in the liver and in other cells of the monocyte-macrophage system in the spleen, lymph nodes, haemal nodes and lungs. There were accumulations of haemosiderin in the proximal convoluted tubular epithelial cells and interstitial macrophages in the kidney (Figs 2c, d). Erythrophagocytosis was evident in the spleen and haemal nodes. Bone marrow from the mid-diaphysis of the femur consisted of a loose, oedematous, fibrillary stroma of low cellularity. The liver had several small foci of periacinar necrosis associated with loss of hepatocytes and infiltration by macrophages containing brown, granular material. Suppurative bronchopneumonia was evident in the cranioventral portions of the lungs. Mild, non-suppurative epicarditis and interstitial myositis were evident. Small numbers of sarcocysts were scattered throughout the myocardium and skeletal muscle. There was hyperplasia of the zona fasciculata of the adrenal gland. A cyst was present in the thyroid gland. Mild chronic enteritis was evident. There were no significant findings in the rumen, reticulum, abomasum or pancreas.Faecal samples collected when the ewe was presented were negative for nematode eggs by the McMaster technique and negative for fluke eggs by the Boray flotation technique. Non-haemolytic Escherichia coli was isolated from faeces submitted for culture on February 13, but faecal cultures were negative for β-haemolytic E coli, as well as Salmonella, Campylobacter and Clostridium species. Faecal smears stained by the Ziehl-Neelsen technique were negative for acid-fast

Human Coinfection with Bartonella henselae and Two Hemotropic Mycoplasma Variants Resembling Mycoplasma ovis

“…In adult sheep, chronic, subclinical infections are typical, unless immunosuppression, including the stress of parturition, triggers the development of hemolytic anemia. Lymphoid depletion within the spleen and lymph nodes was also described in one affected sheep (20). Coinfection of sheep with two distinct strains, differing with respect to a 17-bp fragment, was recently reported in sheep from Hungary (11).…”

“…The organism attaches to erythrocytes and causes "ill thrift," hemolytic anemia, and occasionally icterus, hemoglobinuria, and mortality in lambs (20,24). Decreased growth rate and wool production have also been reported in flocks, as well as immunosuppression with predisposition to pneumonia and abscessation (20), although the mechanisms of immunosuppression have not been elucidated. In adult sheep, chronic, subclinical infections are typical, unless immunosuppression, including the stress of parturition, triggers the development of hemolytic anemia.…”

“…Previously known as "Eperythrozoon ovis," the organism was reclassified as M. ovis based upon 16S rRNA gene sequence analysis (17). The organism attaches to erythrocytes and causes "ill thrift," hemolytic anemia, and occasionally icterus, hemoglobinuria, and mortality in lambs (20,24). Decreased growth rate and wool production have also been reported in flocks, as well as immunosuppression with predisposition to pneumonia and abscessation (20), although the mechanisms of immunosuppression have not been elucidated.…”

“…Transmission among sheep is thought to occur by blood-feeding arthropods, and reuse of needles and blood-contaminated instruments during procedures such as flock immunization and ear-tagging (6,17,20,24). Oral transmission has been documented experimentally (18).…”

A Clinical Case of Severe Anemia in a Sheep Coinfected with Mycoplasma ovis and Candidatus Mycoplasma haemovis' in Hokkaido, Japan

“…Ovine hemoplasmosis is mainly observed in lambs, and is rare in adults [11]. M. ovis is prevalent all over the world, but 'Candidatus M. haemovis', a new ovine hemoplasma, has only been reported in Hungary [5].…”