The influence of dithiosemicarbazone on the immunity of sheep to heartwater.

Protective immunity to heartwater (Cowdria ruminantium infection) is acquired after vaccination with in vitro-attenuated rickettsiae.

A Senegalese (S) stock of Cowdria ruminantium was passaged on bovine umbilical endothelial cells with an average interval of 13.9 days (range, 8 to 34 days) between passages. The virulence of infected bovine umbilical endothelial cultures was tested in susceptible goats and sheep by intravenous inoculation of culture supernatant from passages 2 (51 days in vitro), 3 (69 days), 11 (229 days), 14...

Immunity of tick-exposed seronegative and seropositive small stock challenged with two stocks of Cowdria ruminantium.

Nineteen per cent and 32% of serologically positive sheep and goats in heartwater endemic areas of the Republic of South Africa were susceptible to challenge with, respectively, the Ball 3 and Welgevonden stocks of Cowdria ruminantium. There was good correlation between the results of the indirect fluorescent antibody test and immunity, since without exception all the seronegative animals react...

Heartwater in sheep and goats: a review.

Heartwater (cowdriosis) is an important, often fatal, tick-borne disease of domestic and wild ruminants in sub-Saharan Africa and some Indian Ocean and Caribbean islands. The causal agent, Cowdria ruminantium (Cowdry 1925), is a rickettsia closely related to members of the genus Ehrlichia, and is probably a part of a complex of genomic species. Imported breeds of sheep and goats (especially Ang...

Studies on the Duration of Immunity conferred by a Live Modified Sheep Pox Tissue Culture Virus Vaccine

The Effect of Oral Consumption of Guggul (Commiphora Mukul) Resin on Performance and Humoral Immunity Response of Broilers

This experiment was conducted to determine the effects of the oral consumption of guggulplant resin on the performance and humoral immunity response of broiler chicks. For doing this experiment, 320 one-day old chicks of the Cobb 500 strains, in a Completely randomized design with 4 treatments and 4 replicates were used. Experimental diets include: control diet (without the guggul), control die...