Acquisition of protective immunity in Geochelone pardalis against Amblyomma marmoreum (Acari: Ixodidae) nymphal ticks

Abstract

Significant increases in serum globulins (α₁ , α₂ , β and γ) were observed in mountain leopard tortoises (Geochelone pardalis) after they had been immunized with nymphal homogenates of Amblyomma marmoreum. There was a concomitant significant increase in the numbers of leukocytes (lymphocytes, basophils, monocytes and eosinophils). Resistance to nymphal-challenge infestations was manifested by reduced feeding time, lower engorgement masses, and significantly fewer (P < 0,0001) numbers of nymphs that moulted. These findings are contrary to the generally reported phenomenon, that ticks do not induce resistance in their natural hosts.