Laboratory Infection of Amblyomma variegatum Ticks with Cowdria ruminantium and Sustained Nymp. Infectivity after a Long preservation Period.

LAWAL, AI, AGBEDE R.I.S. and OTOBO, S.

ABSTRACT: Laboratory colonies of Amblyomma variegatium nymphae were established by incubating thirty fully and eighteen partially engorged female ticks collected from sedentary herds in Zaria. They were incubated at 28°C and 80% relative humidity. Preoviposition periods ranged from 7 to 10 days (mean 8.5+ 1.5) and 9 to 11 days (mean 10±1.0) for the fully and partially engorged ticks respectively. The eggs maintained under the same incubation conditions hatched ‘between 40-43 days (mean 41.5 +1.5) and
40 to 59 days (mean 49±9.5) post oviposition for the fully and partially engorged ticks respectively. The larvae were infected by feeding them on a heartwater infected goat using ear bags. The resultant nymphae transmitted heartwater to susceptible goats after 11 and 52 weeks, of preservation in the incubator maintained at WOC and 80% relatively humidity.

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