| development of resistance in laboratory animals to adults of the tick rhipicephalus evertsi evertsi. | acquired resistance to adults of the two-host tick rhipicephalus evertsi evertsi neumann has been demonstrated in guinea-pigs and rabbits. four infestations of both hosts with r.e.evertsi adults resulted in a significant reduction in the mean weight of the engorged females. a decline in the mean weight of the female ticks was also observed in ticks which fed on a rabbit previously injected with serum taken from a rabbit resistant to r.e.evertsi. this suggests that humoral immunity may have an im ... | 1991 | 1768898 |
| viraemic transmission of crimean-congo haemorrhagic fever virus to ticks. | in order to determine the way in which vertebrates infected with crimean-congo haemorrhagic fever (cchf) virus and potential ixodid tick vectors interact in nature, immature and adult ticks of several species were fed on viraemic mammals and then assayed for virus content at varying times after feeding. cchf virus was not isolated from ticks of six species tested after feeding as adults and immature forms on sheep with viraemia of 10(2.5-3.2) ld 50/ml, nor from larval ticks fed on guinea-pigs an ... | 1991 | 1902186 |
| expression of acquired immunity to immature stages of the tick rhipicephalus evertsi evertsi by rabbits and guinea-pigs. | acquired immunity in guinea-pigs and rabbits to immature stages of the two-host tick rhipicephalus evertsi evertsi neumann was demonstrated. repeated infestations of both hosts with larvae resulted in a significant reduction in the weight of later engorged nymphs. a sharp decline in the numbers of nymphs which successfully fed on both hosts was also observed. this study provides evidence for a gradual decrease in the mean weight of engorged nymphs towards the end of the detachment period suggest ... | 1989 | 2519645 |
| resistance and cross-resistance in guinea-pigs and rabbits to immature stages of ixodid ticks. | infestation of guinea-pigs and rabbits with larvae of any one of five species of ticks, rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma hebrauem koch, amblyomma variegatum fabricius and ixodes ricinus l., conferred resistance in the animals when exposed to subsequent infestations with the same tick species. resistance to infestations by other tick species was not observed. | 1989 | 2519683 |
| [sensitivity of laboratory animals to rhipicephalus evertsi evertsi paralysis]. | | 1982 | 7124196 |
| the effect of host resistance on the metabolic rate of engorged females of rhipicephalus evertsi evertsi. | this study investigated the effect of acquired resistance in guinea-pigs on the metabolic rate of adult females of the tick rhipicephalus evertsi evertsi. guinea-pigs were subjected to three successive infestations of ticks and the rate of co2 production (vco2) measured in first and third infestation engorged females. ticks which fed on resistant hosts showed a 52% decrease in mass compared to ticks that fed on naive animals. reduction in mass was accompanied by a decrease in vco2 (mlh-1) per ti ... | 1995 | 7548947 |
| the effects of tick numbers and intervals between infestations on the resistance acquired by guinea-pigs to adults of rhipicephalus evertsi evertsi (acari: ixodidae). | guinea-pigs were infested three times at short (1 week) intervals or long (10 week) intervals between successive infestations with low (1), medium (8) and high (15) numbers of adult rhipicephalus evertsi evertsi. to compare the resistance developed by the hosts at short and long intervals between infestations, a challenge (fourth) infestation was performed with the high number of ticks. resistance was assessed by comparing the mean weight of engorged female ticks that dropped from the hosts. con ... | 1994 | 7555412 |