TAILIEUCHUNG - Black's veterinary dictionary 21st edition - B

Từ điển thú y vần B | B Cells One of the 2 types of lymphocytes. They are important in the provision of immunity and they respond to antigens by dividing and becoming plasma cells that can produce antibody that will bind with the antigen. Their source is the bone marrow in mammals and the Bursa of Fabricius in birds. It is believed that the function of B cells is assisted by a substance provided by T CELLS. With haptens see HAPTEN it is apparently the B cells which recognise the protein carrier and the T cells which recognise the hapten. See also LYMPHOCYTE IMMUNE RESPONSE. B Virus This is a herpes virus found in monkeys which gives rise in man to an encephalitis with an almost 100 per cent mortality. It may be transmitted to man from monkeys especially newly imported rhesus and cynomolgus monkeys. Lesions on the face and lips of monkeys should arouse suspicion of this condition. It is believed that B virus herpes simplex virus and Aujeszky s disease virus have a common origin. Babesia Babesia is another name for piroplasm one of the protozoan parasites belonging to the order Haemosporidia. These are generally relatively large parasites within the red blood cells and are pear-shaped round or oval. Multiplication is by division into 2 or by budding. Infected cells frequently have 2 pyriform parasites joined at their pointed ends. Sexual multiplication takes place in the tick. Babesiosis Piroplasmosis Nearly all the domestic mammals suffer from infection with some species of Babesia sometimes more than 1 species may be present. The general symptoms are the appearance of fever in 8 to 10 days after infection accompanied by haemoglobinuria icterus unless treated 25 to 100 per cent of the cases are fatal. Red blood cells may be reduced in number by two-thirds. Convalescence is slow and animals may remain salted for 3 to 8 years. Transmission Development occurs in certain ticks which transmit the agent to their offspring. The various species are similar but are specific to their various .

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