| investigations of breakdowns in protection provided by living babesia bovis vaccine. | field investigations of protection afforded by live babesia bovis vaccine in australia revealed that a ninefold increase in vaccine failures occurred in the period from 1985 to 1990. laboratory trials using 189 experimental cattle were conducted to evaluate the protection afforded by the babesia bovis strain used in the commercial vaccine during this time. four isolates from clinical cases of babesiosis in vaccinated cattle were assessed. the results showed that the strain used in the vaccine du ... | 1992 | 1496802 |
| serological studies of babesiosis and anaplasmosis of cattle. | bos indicus-crossbred calves exposed to natural babesia bovis infection in wet and dry tropical environments in northern queensland were tested for antibodies using the indirect haemagglutination (iha) test. there was evidence of maternal antibodies suggesting endemicity of b. bovis in the 2 environments. within one year 35.3 to 94.6% of the calves had acquired b. bovis infection. the highest titres and most rapid conversion rates were observed just after the wet season when the tick population ... | 1982 | 7181776 |
| studies on failure of t strain live babesia bovis vaccine. | field investigations of the protection afforded by the australian live babesia bovis vaccine used in the early 1990s (t strain) revealed inadequate vaccine-induced protection in certain herds. vaccination/challenge trials using 207 experimental cattle were conducted to evaluate the protection afforded by t strain b bovis against field isolates from these herds. the trials investigated whether isolates that could 'break-through' t strain immunity were present in the field, the ability or inabilit ... | 1995 | 8579560 |
| identification of an immunodominant 40 kda merozoite antigen common to the australian t and dixie vaccine strains of babesia bovis and the development of diagnostic tests specific for these strains. | antigenic differences among australian vaccine and field strains of babesia bovis were investigated in an attempt to identify strain specific antigens. immunoblots revealed substantial differences between the current vaccine strains, designated t and dixie, and previous vaccine strains and field isolates collected on properties where vaccination with the t or dixie strains had failed to provide complete protection against tick-borne challenge. a major difference was an immunodominant 40 kda anti ... | 1995 | 8747906 |
| development of effective living vaccines against bovine babesiosis--the longest field trial? | between 1959 and 1996, research was performed to change a vaccine against babesiosis in australia and to improve it as actual or threatened untoward field responses became apparent. the most significant change occurred in 1964 with the traditionally used carriers of babesia being replaced as vaccine donors by acutely infected splenectomised calves. this ensured the infectivity of the vaccine and was fortuitously associated with a reduction in the virulence of babesia bovis in vaccine. since then ... | 1997 | 9279577 |
| genotypic diversity in field isolates of babesia bovis from cattle with babesiosis after vaccination. | to determine whether particular genotypes of babesia bovis were common to field isolates obtained from cattle properties in queensland where the b bovis vaccine had apparently failed. | 1997 | 9293339 |
| overcoming constraints to meeting increased demand for babesia bigemina vaccine in australia. | demand for live trivalent tick fever vaccine containing babesia bovis, babesia bigemina and anaplasma centrale produced by the department of primary industries, queensland, has increased from less than 10,000 doses in 1988 to 500,000 doses in 2001. this paper describes a series of trials aimed at overcoming certain constraints to obtain b. bigemina parasitised erythrocytes (pes) on a large enough scale from infected splenectomised calves to meet the demand. passage through a series of splenectom ... | 2003 | 12935736 |
| serological evidence of exposure to tick fever organisms in young cattle on queensland dairy farms. | to compare the features of farms on which the exposure of young cattle to tick fever organisms is sufficient to ensure that immunity is high and the risk of clinical disease is low (endemic stability) with those of farms on which exposure is insufficient to induce widespread immunity (hence without endemic stability); to examine the relationships between the management of ticks and tick fever, and endemic stability to babesia bovis, b. bigemina and anaplasma marginale. | 2003 | 15080428 |