Increased pathogenicity of an Ehrlichia-like agent after passage through Amblyomma hebraeum: a preliminary report.
نویسنده
چکیده
After being passaged through 3 generations of Amblyomma hebraeum, an Ehrlichia-like agent isolated from an adult Hyalomma truncatum female became more pathogenic and elicited a disease in sheep indistinguishable from heartwater. Cross-immunity between this agent and several stocks of Cowdria ruminantium and high levels of antibody elicited by the agent against 2 stocks of C. ruminantium in the indirect fluorescent antibody test, confirmed its close relationship to Cowdria.
منابع مشابه
The detection of antibodies cross-reacting with Cowdria ruminantium in the sera of domestic ruminants in regions of South Africa where Amblyomma hebraeum does not occur.
High levels of seropositivity, in all probability attributable to Ehrlichia, were recorded in the serum of domestic ruminants throughout districts in South Africa where Amblyomma hebraeum, the vector of the heartwater agent, does not occur. The antibodies, detected with the indirect fluorescent antibody (IFA) and the indirect ELISA tests, cross-reacted with Cowdria ruminantium, which was used a...
متن کاملThe presence of Cowdria ruminantium antigen in various tissues of Amblyomma hebraeum imagines as detected by an enzyme-linked immunosorbent assay.
Investigation into the presence of C. ruminantium antigen, using an enzyme-linked immunosorbent assay (ELISA) in various tick tissues and haemolymph of adult Amblyomma hebraeum ticks revealed that the organism invades a number of body parts and can be demonstrated in A. hebraeum. In females, the gut, salivary glands, hypodermis and synganglion and in males, the salivary glands and gut showed th...
متن کاملThe detection of antibodies to Cowdria ruminantium in serum and C. ruminantium antigen in Amblyomma hebraeum by an enzyme-linked immunosorbent assay.
A sensitive and reliable enzyme-linked immunosorbent assay for the detection of antibodies to Cowdria ruminantium in serum and C. ruminantium antigen in Amblyomma hebraeum nymphae is described. For the screening of antibodies, C. ruminantium from A. hebraeum nymphae, partially purified by wheat-germ lectin affinity chromatography, was used as antigen. To screen nymph populations, sera from eith...
متن کاملA method for determining the Cowdria ruminantium infection rate of Amblyomma hebraeum: effects in mice injected with tick homogenates.
Amblyomma hebraeum ticks, collected in the field and individually homogenized, were injected into mice. Thirteen out of 240 ticks were shown to be infected with the heartwater agent. Antibodies against Cowdria ruminantium were detected in the sera of the mice by means of the indirect fluorescent antibody test. Giemsa-stained smears, prepared from the haemocytes of the ticks, revealed morphologi...
متن کاملAdult Amblyomma hebraeum burdens and heartwater endemic stability in cattle.
Several conclusions of importance to studies on the epidemiology of heartwater were drawn from an investigation in which the numbers of adult Amblyomma hebraeum ticks, to which a closed herd of Hereford cattle were exposed over a period of 6 1/2 years, were manipulated. With a tick Cowdria ruminantium infection rate of 3-5%, an endemically stable situation was created by dipping the herd only w...
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ورودعنوان ژورنال:
- The Onderstepoort journal of veterinary research
دوره 57 4 شماره
صفحات -
تاریخ انتشار 1990