Ichthyophthiriasis in carp Cyprinus carpio: infectivity of trophonts prematurely exiting both the immune and non-immune host

Diseases of Aquatic Organisms

T. Wahli¹  R. A. Matthews¹ 

关键词: Ichthyophthirius multifiliis;    Carp;    Infectivity;    Immune evasion;    Premature exit;   

DOI  :  10.3354/dao036201

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Ichthyophthirius multifiliis exposed to naturally immunised carp established short-term infections, the majority of parasites actively emerging within 2 h of entering the epidermis. A small, but significant, number of these expelledparasites were shown to retain theront-like properties with the capacity to directly re-invade a further fish host. Infectivity fell rapidly with time in the host and was comparable to that of trophonts of a similar age artificially induced to emerge fromnon-immune hosts with the aid of MEM (minimal essential medium). Trophonts recovered with MEM from immune carp 2 to 8 h post infection rarely established infections upon exposure to susceptible new hosts and no infections resulted from older trophontsrecovered after 8 to 24 h exposure; older trophonts, however, represented only a small percentage of the original parasite population. A low level of infectivity was recorded in trophonts collected with the aid of MEM from non-immune carp after up to 24 hof infection. The results are discussed in relation to theront transformation and evasion of the host immune response.

【 授权许可】

Unknown