Eperythrozoon Ovis Research Articles

The effect of artificial Eperythrozoon ovis infection on the growth rate of stressed and nonstressed sheep.

Australian Veterinary JournalVolume 66, Issue 6 p. 184-186 The effect of artificial Eperythrozoon ovis infection on the growth rate of stressed and non-stressed sheep TJ NICHOLLS, TJ NICHOLLS Department of Agriculture and Rural Affairs Regional Veterinary Laboratory Benalla, Victoria 3672 AustraliaSearch for more papers by this authorPI VEALE, PI VEALE Department of Agriculture and Rural Affairs Regional Veterinary Laboratory Benalla, Victoria 3672 AustraliaSearch for more papers by this authorD. OVEREND, D. OVEREND Department of Agriculture and Rural Affairs Regional Veterinary Laboratory Benalla, Victoria 3672 AustraliaSearch for more papers by this author TJ NICHOLLS, TJ NICHOLLS Department of Agriculture and Rural Affairs Regional Veterinary Laboratory Benalla, Victoria 3672 AustraliaSearch for more papers by this authorPI VEALE, PI VEALE Department of Agriculture and Rural Affairs Regional Veterinary Laboratory Benalla, Victoria 3672 AustraliaSearch for more papers by this authorD. OVEREND, D. OVEREND Department of Agriculture and Rural Affairs Regional Veterinary Laboratory Benalla, Victoria 3672 AustraliaSearch for more papers by this author First published: June 1989 https://doi.org/10.1111/j.1751-0813.1989.tb09799.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume66, Issue6June 1989Pages 184-186 RelatedInformation

A serological survey of Eperythrozoon ovis in goats and sheep in Tasmania.

Australian Veterinary JournalVolume 66, Issue 4 p. 122-123 A serological survey of Eperythrozoon ovis in goats and sheep in Tasmania RW MASON, RW MASON Veterinary Laboratory Branch, Mt Pleasant Laboratories PO Box 46, Kings Meadows, Tasmania 7249Search for more papers by this authorA. CORBOULD, A. CORBOULD Veterinary Laboratory Branch, Mt Pleasant Laboratories PO Box 46, Kings Meadows, Tasmania 7249Search for more papers by this authorP. STATHAM, P. STATHAM Veterinary Laboratory Branch, Mt Pleasant Laboratories PO Box 46, Kings Meadows, Tasmania 7249Search for more papers by this author RW MASON, RW MASON Veterinary Laboratory Branch, Mt Pleasant Laboratories PO Box 46, Kings Meadows, Tasmania 7249Search for more papers by this authorA. CORBOULD, A. CORBOULD Veterinary Laboratory Branch, Mt Pleasant Laboratories PO Box 46, Kings Meadows, Tasmania 7249Search for more papers by this authorP. STATHAM, P. STATHAM Veterinary Laboratory Branch, Mt Pleasant Laboratories PO Box 46, Kings Meadows, Tasmania 7249Search for more papers by this author First published: April 1989 https://doi.org/10.1111/j.1751-0813.1989.tb09767.xCitations: 9AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume66, Issue4April 1989Pages 122-123 RelatedInformation

Effect of [formula omitted] on the lysis of sheep erythrocytes in the complement fixation test

When erythrocytes from sheep experimentally infected with Eperythrozoon ovis were used in the titration of reagents for a standardised complement fixation test, increased amounts of both haemolysin and complement were required for erythrocyte lysis compared with preinfection titrations. The haemolysin requirement increased by up to 125% at 55 days post-infection and complement requirement increased by up to 40% at 40 days post-infection. These changes appeared to correlate with the development of a macrocytic anaemia in affected sheep rather than E. ovis parasitaemia. The results emphasise the need to carefully monitor the haematological parameters of sheep used as sources of erythrocytes for the complement fixation test.

Detection of antibodies to Eperythrozoon ovis by the use of an enzyme-linked immunosorbent assay

Specific antibody to Eperythrozoon ovis was detected by an enzyme-linked immunosorbent assay (ELISA) in the sera of infected sheep. In the presence of parasite antigen, positive control serum showed a reaction approximately eight times that of negative serum. When compared to an immunofluorescent antibody test (IFAT), the ELISA was eight times more sensitive. Positive control sera gave a titre of 1:3200 by IFAT and 1:25,600 by ELISA. Through the use of a reference titration curve ELISA could be used as a semi-quantitative system to determine antibody levels in test sera.

The effects of Eperythrozoon ovis in sheep

Infection of adult sheep with a single strain of Eperythrozoon ovis led to three different situations. First, the animal resisted the organism and no haematological changes occurred. Second, the host developed a controllable parasitaemia in which erythrocyte values fell shortly after peak parasitaemia and then returned to normal. Third, the host failed to control the parasitaemia and chronic low grade anaemia developed. Dexamethasone sometimes caused a resurgence of parasitaemia in sheep.

Changing morphology of Eperythrozoon ovis

Light microscopy studies of Eperythrozoon ovis in sheep revealed that Giemsa stain was only less reliable than acridine orange as a means of parasite identification when low parasitaemias were present. The morphology of E ovis altered as the degree of parasitaemia increased.

Separation of Eperythrozoon ovis from erythrocytes.

Separation of Eperythrozoon ovis from erythrocytes.

Chemotherapeutic efficacy of imidocarb dipropionate on experimental Eperythrozoon ovis infection in sheep.

Non-splenectomised Cheviot and Soay sheep experimentally infected with Eperythrozoon ovis were treated subcutaneously with two doses of 4 mg/kg of imidocarb dipropionate 24 hours apart. A rapid reduction in E. ovis parasitaemias following the first injection of imidocarb was observed and E. ovis organisms were not demonstrable 48 hours after the first treatment. However, recrudescences of infection were observed 14 and 28 days after treatment in the Soay and Cheviot sheep respectively. Side-effects associated with treatment were registered in the Cheviot sheep but not in the Soay sheep.

A modified indirect immunofluorescent assay for the detection of antibody to Eperythrozoon ovis in sheep.

Experimental ovine eperythrozoonosis was studied using Giemsa staining of blood films and a modified indirect immunofluorescent antibody assay (IFAA). The serums of 21 Border Leicester Merino cross lambs between 12 weeks and 7 months-of-age were analysed before and after infection with Eperythrozoon ovis (E. ovis) using the IFAA test. No rise in the IFAA titre was seen until day 7 and this coincided with the first detection of E. ovis organisms in blood smears stained with Giemsa. The percentage of E. ovis infected red blood cells peaked on day 14, but the IFAA titre did not peak until day 35. Titres to E. ovis, on average, had begun to drop by day 63. There was considerable individual variation in response to E. ovis infection as measured by the IFAA. Titres as high as 6,400 were observed in individual sheep at the peak of E. ovis parasitaemia of red cells. One sheep had a titre of 51,200 nineteen days after infection, and titres of 3,000 were maintained for several months in a few sheep. The assay proved reliable, and up to 100 samples per day could be tested. The antigenicity of the slide preparations was found to be satisfactory after storage for 6 months at -20 degrees C and 4 degrees C and for 28 months at -70 degrees C. Temperature fluctuations during storage rendered slides unsuitable for the IFAA after these times. A method of storing E. ovis infected blood in liquid nitrogen is described.

Humoral immune response of sheep to infection with Eperythrozoon ovis

Circulating antibody was detected by an indirect fluorescent antibody test (IFAT) in the serum of sheep infected experimentally with Eperythrozoon ovis. Antibodies were first detected 15 to 32 days after infection with E ovis and titres peaked at 41 days. This antibody may be associated, at least in part, with protection against infection with E ovis since the initial increase in antibody titre coincided with a fall in the primary parasitaemia. A role for antibody is suggested further by the fact that the prepatent period of infection was prolonged by one day and the parasitaemia initially remained at low levels in infected sheep protected by passively transferred hyperimmune serum. Moreover, following primary infection, acquired immunity was manifest by a lack of parasitaemia following challenge infections while increased IFA titres were observed. No evidence of opsonic activity was observed in an in vitro erythrophagocytosis test in that neither mouse macrophages nor sheep monocytes phagocytosed E ovis infected or uninfected erythrocytes sensitised with hyperimmune serum.

Mortality in weaner sheep in South Australia under different regimes of anthelmintic treatment

Causes of mortality in weaner sheep subjected to differing regimes of anthelmintic treatment were investigated at Kybybolite, S.A., between 1976 and 1981. The greatest mortality occurred in untreated sheep during the winter months, and was directly attributable to nematode infections, principally Trichostrongylus vitrinus. Deaths occurred during the summer months of the later years of the experiment. Nematode infections were considered to be a predisposing cause, with anaemia possibly due to infection with Eperythrozoon ovis as the precipitating factor in mortalities.

The protection of lambs from eperythrozoon infection while suckling Eperythrozoon ovis carrier ewes

When lambs born to and suckling Eperythrozoon ovis carrier ewes were inoculated with heparinised blood containing large numbers of E. ovis organisms, the lambs were either sterilised of the infection or patent infection was suppressed till the lambs were weaned. In vitro infection, transplacental transfer of antibodies or soluble antigens could not be demonstrated.

緬羊のエペリスロゾーン症に関する研究

Pyrexia, anemia, tachypnea, palpitation, and hemoglobinuria were manifested in experimental, as well as spontaneous, cases of eperythrozoonosis in sheep. Eperythrozoon ovis was polymorphic in blood smearsprepared from spontaneous cases and identified electron microscopically.In the case of artificial infection E. ovis appeared in the blood 15 days after inoculation, but disappeared almost completely at the climax of anemia. It seemed to have multiplied mainly in the bone marrow before it did in the peripheral blood.

Investigations on a Babesia isolated from Scottish sheep.

The pathognomic, serologic and morphometric identity of a Babesia sp. recently isolated from sheep in Argyllshire was studied. Initially, problems were encountered due to the occurrence of Eperythrozoon ovis as a contaminant of the isolate and treatment with neoarsphenamine failed to remove it. Finally, a combination of oxytetracycline therapy and rapid passage allowed isolation of the Babesia sp. and its preservation in the form of a glycerolized, infected blood stabilate. Inoculation of the stabilate into splenectomized sheep produced a mile non-pyrogenic disease. Serologically the parasite was seen to have no affinity with either of the two Babesia recognized as parasitizing sheep, but some affinity with the cattle parasite B. divergens. Morphometrically it was seen to have affinity with the deer parasite B. capreoli and with the Babesia sp. isolated from red deer in Scotland, and the low number of budding forms of the parasite seen suggested that the parasite might be reproducing slowly in an alien host. It was concluded that the parasite was likely to be B. capreoli derived from red deer via the tick Ixodes ricinus.

Culex annulirostris as a vector of Eperythrozoon ovis infection in sheep

Eperythrozoon ovis, a blood parasite of sheep, was transmitted from carrier lambs to susceptible lambs by the interrupted feeding of the mosquito Culex annulirostris. The circumstances of some of the transmissions were similar to those encountered in the field, in that carrier and susceptible lambs were exposed to a natural population of mosquitoes, while in another transmission an artificial means of containment of the mosquitoes was used. Infective E. ovis organisms were shown to be present in and/or on Cx. annulirostris for at least 14 hours by the inoculation of physiological saline-extracted material from macerated mosquitoes fed on E. ovis carrier lambs.

Effect of Eperythrozoon ovis infection on the reductive potential of sheep erythrocytes

Abstract Reduced glutathione (GSH) and methaemoglobin were measured in sheep blood during an infection cycle of Eperythrozoon ovis and in uninfected control blood. The GSH levels in infected erythrocytes were significantly lower in the latter half of the infection cycle. Incubation with acetylphenylhydrazine (APH) resulted in negligible leves in infected cells whereas control cells were approximately 45% normal. Infection with E. ovis had little effect on methaemoglobin levels. However, incubation with APH caused a marked increased of the methaemoglobin levels in both infected and control blood; the control methaemoglobin levels were significantly higher. It was concluded from these observations that E. ovis interfered with maintenance of GSH within erythrocytes to an extent that when challenged with an oxidizing chemical erythrocyte membrane integrity could be lost. In addition E. ovis may bave provided some protection against oxidative damage for the heme portion of the haemoglobin molecule or the amount of oxidative damage to haemoglobin was further advanced in the infected cells.

Observations on the pathology ofEperythrozoon ovisinfection in sheep

Abstract The main pathological features of experimental Eperythrozoon ovis infection were an increase of spleen weight by up to 250% at the peak of parasitaemia and an increase in liver weight by 36%. Haemosiderin was present in the kidneys, livers and spleens of all infected sheep at the peak and late stages of parasitaemia. Control sheep had haemosiderin in the spleen only. On the basis of these findings, intravascular haemolysis appears to be the predominant mode of red cell removal. Although not observed histologically, some erythrophagocytosis by the spleen and liver probably occurs in the course of the infection.

The effect of Eperythrozoon ovis infection on the glucose level and some acid-base factors in the venous blood of sheep.

Eperythrozoon ovis infected sheep have low venous blood glucose levels and correspondingly increased blood lactic acid levels as compared with control sheep. Acid-base studies showed that these changes were accompanied by significant falls in venous pH, and standard bicarbonate as well as a negative base excess. All these changes were considered to result from the increased alvcolytic activity of infected erythrocytes. The acidosis and hypoglycaemia associated with E. ovis infection, while not having any apparent effect on young, well-fed sheep, could be potentially serious in pregnant ewes and in sheep on a low plane of nutrition.

緬羊のEperythrozoonosisに関する研究

In November, 1975, some adult sheep produced in Japan began to suffer from fever, anemia, palpitation, tachypnea, and hemoglobinuria. Light and electron microscopy revealed that many parasitic organism of Eperythrozoon ovis were present on the surface of erythrocytes. With an increase in parasitic rate, the erythrocyte count, hematocrit, and hemoglobin values decreased, erythrocytic resistance was reduced, and hemoglobin plasma appeared.When a splenectomized and an intact sheep were inoculated with blood from a spontaneously infected sheep, Ep. ovis began to appear in their peripheral blood 10 and 12 days after inoculation, respectively. The inoculated sheep manifested the same clinical signs and hematological changes as the spontaneously infected one. This report was the first to confirm the presence of Ep. ovis in Japan.

Preliminary observations on the use of the capillary flocculation test for the diagnosis of heartwater (Cowdria ruminantium infection)

A capillary flocculation test was developed to diagnose heartwater disease of ruminants. Antigen was prepared from the brains of cattle and goats highly infected with Cowdria ruminantium. Sera were obtained from experimentally infected ruminants which either recovered naturally or with the aid of oxytetracycline treatment. Antibodies were first detected one to two weeks after clinical recovery or after treatment, and persisted for periods varying between one and four weeks. Control sera collected from cattle (sheep) and goats in the Netherlands where heartwater does not occur, or from animals serologically positive for Anaplasma marginale or Eperythrozoon ovis infections, did not react to the test.