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Eperythrozoon ovis, an erythrocytic agent that causes haemolytic anaemia in sheep and goats, occurs worldwide and is currently thought to be a rickettsia. To determine the relationship between this agent and other haemotrophic bacterial parasites, the 16S rRNA gene of this organism was sequenced. Phylogenetic analysis revealed that this wall-less bacterium is not a rickettsia, but a mycoplasma. This mycoplasma is related closely to several other uncultivated, epierythrocytic mycoplasmas that comprise a recently identified group, the haemotrophic mycoplasmas (haemoplasmas). The haemoplasma group is composed of former Eperythrozoon and Haemobartonella species, as well as newly identified epierythrocytic mycoplasmas. Haemoplasmas parasitize the surface of erythrocytes of a wide variety of vertebrate animal hosts and are transmitted mainly by blood-feeding arthropod vectors. Recognition that E. ovis is a mycoplasma provides a new approach to dealing with this bacterium. It is proposed that E. ovis should be reclassified as Mycoplasma ovis comb. nov.Eperythrozoon ovis is an uncultivated, wall-less bacterium that parasitizes the surface of sheep erythrocytes. This organism is transmitted by blood-feeding arthropods and parasitizes animals in sheep-rearing regions throughout the world. Signs of infection include mild to severe haemolytic anaemia, as well as icterus; animals may exhibit poor weight gain and depression, but death is rare in adults. Infections are frequently unapparent and chronic. E. ovis also infects goats, in which it results in more severe disease (Splitter et al., 1956;Kreier & Ristic, 1963;Daddow, 1979;Mason et al., 1989;Mason & Statham, 1991).As E. ovis has not been cultivated, diagnosis is made by detection of organisms on erythrocytes in Romanowskytype or acridine orange-stained blood smears and by serological methods. Parasitism of erythrocytes often occurs at a low level and is transient; detection requires examination of repeated blood smears. However, erythrocyte parasitaemia can be as high as 100 % in our experience; a high level of parasitaemia can occur even in subclinical infection and can persist for months (Overas, 1969;Brun-Hansen et al., 1997). E. ovis is completely resistant to penicillin and other antimicrobial agents that target the cell wall. Also, tetracycline treatment does not eliminate this agent from chronically infected animals. This organism has been thought to be a rickettsia because of its obligate parasitism, erythrocyte localization, small size, staining properties and transmission by arthropod vectors. E. ovis and a number of similar haemotrophic bacteria have been classified in the order Rickettsiales, family Anaplasmataceae, in the genera Haemobartonella and Eperythrozoon (Kreier & Ristic, 1984;Kreier et al., 1992). Recently, phylogenetic analysis of 16S rRNA gene sequences from four of these bacteria, Haemobartonella felis, Haemobartonella muris, Eperythrozoon suis and Eperythrozoon wenyonii, has demonstrated that these wallless bacteria are not rickettsiae, but tha...

Anatoxin-a, a toxin produced by several genera of blue-green algae, is considered a potent neurotoxin. Ingestion of water contaminated with the toxin results in acute neurological signs and often death. This report describes fatal cases of anatoxin-a ingestion in 6 dogs, with confirmation of anatoxin-a exposure by liquid chromatography/tandem mass spectrometry (LC-MS/MS/MS). In 1 outbreak, 3 dogs developed seizures and died within an hour after swimming in a river in California, while the other outbreak involved 3 dogs that died within 1 hour after swimming in a pond in Ontario. Anatoxin-a poisoning is rarely reported in dogs as a cause of acute neurological signs and death. However, increased occurrences of blue-green algae blooms in North America make this neurotoxin an important consideration in the diagnosis of sudden death associated with environmental water exposure. This brief communication reports on the isolation and detection of anatoxin-a from environmental water sources and the stomach contents of North American dogs dying of acute neurotoxicosis. This demonstrates the first documented cases of anatoxin-a poisoning in dogs in North America and the importance of LC-MS/MS/MS in identifying neurotoxins responsible for sudden death in cases of suspected blue-green algae toxicosis; especially those cases showing no gross or histological lesions.

Total protein, nucleated cell count, and percentage of neutrophils in synovial fluid were significantly increased after arthroscopic lavage; however, synovial fluid SAA was not affected by this procedure. Further research is warranted to validate synovial fluid SAA as a monitoring tool during treatment of septic arthritis.

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