blood, which is then bottled for use. The vaccine is delivered containing the live protozoa to induce immunity without acute disease. Theileria annulata can be grown and attenuated in virulence by means of infecting cell cultures with the schizont stage of the protozoan. This is delivered as a frozen vaccine from which live parasites are thawed out before injection. Cattle can be protected against East Coast fever by an infection-and-treatment procedure. Rhipicephalus appendiculatus ticks are infected with Theileria parva under laboratory conditions; theilerial sporozoites are extracted from the ticks and stored in liquid nitrogen; infective doses of the live vaccine are delivered to identified cattle and a few days later a protective dose of antibiotic is delivered to stop the infection from developing into clinical East Coast fever. Vaccines are often highly effective, but the live parasite vaccines have problems of potential contamination with other microbes and induction of a carrier state which may be unwanted. Intensive attempts are made to develop vaccines to control these diseases using a recombinant DNA techniques to synthesize the relevant antigens, but as with vaccines against human malaria this is a difficult technological challenge. A commercial vaccine was developed in Australia against Rh. microplus. It acts against a glycoprotein molecule that is exposed on the outer membrane of digestive cells of the gut of feeding ticks. This molecule is synthesized using recombinant DNA technique to make the antigen of the vaccine. Vaccinated cattle develop antibodies circulating in their blood. When the Rh. microplus female ticks engorge with blood, the antibody reacts with the natural antigen in their guts so strongly that digestion is disrupted and the reproductive rate of the ticks is reduced. This vaccine is manufactured in Australia and a closely similar vaccine is manufactured in Cuba. References External links Ticks. Centers for Disease Control and Prevention, USA. Tick-borne Livestock Diseases and their Vectors: Five-part Series. Food and Agriculture Organization of the United Nations. Ticks. Livestock Veterinary Entomology. Texas A&M AgriLife Extension. Tropical bont tick, Amblyomma variegatum. Prine, K. C. and A. C. Hodges. EENY-518. University of Florida IFAS. Published 2012, updated 2013. Overview of tick paralysis. Parasitic Insects, Mites and Ticks: Genera of Medical and Veterinary Importance Wikibooks Further reading Baker, A.S. (1999) Mites and Ticks of Domestic Animals: an identification guide and information source. London: The Stationery Office, . Bowman, A. S. & Nuttall, P. A. (2008) Ticks: Biology, Disease and