Lernaea spp. was identified as a widespread problem in
West Malaysia and various aspects of the parasite were
studied. A survey of the distribution of Lernaea spp. in
West Malaysia revealed its presence in all the 8 government
owned fish breeding stations, 104 privately owned farms and
4 out of 5 consignments of imported fingerlings. The
Lernaea spp. present in these ponds were identified as L.
piscinae and L. cyprinacea “Asian” form (=b.elegans) and its
morpha forms, L. ctenopharyngodonis and L.guadrinucifera.
The life cycles of L. cyprinacea and L. piscinae were
determined under laboratory conditions.
Infection of ~. auratus with the offspring of L.
cyprinacea “Asian” form produced adult females similar to
the maternal form and another form identified as b.
ctenopharyngodonis. A. nobilis, infected with L. cyprinacea
“Asian” form and L. piscinae produced only species identical
to the maternal form. A high degree of polymorphism was
revealed and was further investigated.
Morphometric studies on the larval stages and adult female
parasites were investigated and reliable characteristics for
the identification of Lernaea is discussed.
The distribution frequency of b. cyprinacea on 3 host
species and L. piscinae on A. nobilis in aquarium tanks was
goodness of
tested for/fit with the theoretical negative binomial
distribution. The bases of fins were found to be the
preferred site of infection for both species.
studies on growth performance of A. nobilis
infected with L. piscinae in ponds, revealed a significant
reduction in Specific Growth Rates. Infected fish had a
higher mortality than uninfected fish. A decrease in
parasite infection on the body surface after 3 months was
associated with its appearance in the eye. A challenge
infection did not establish and the fish were suspected of
being immune.
Histopathological studies showed a typical inflammatory
response with the formation of a granuloma. Eosinophilic
granular cells, lymphocytes, and club cells which were
identified in the hosts immune to the infection, were
believed to play an important role in the rejection of
parasites.