Different manifestations of Thelohanellus nikolskii infection in carp (Cyprinus carpio)

Abstract

Thelohanellosis is a disease that occurs in all carp categories. The cause is protozoa Thelohanellus nikolskii Achmerov, 1955. It manifests itself in two forms. The first form occurs on the fins in oneyear- old carp fry and the second one occurs on scales in two-yearold, three-year-old and older categories of common carp (Cyprinus carpio). The researches conducted between 2008 and 2012 covered 22 fish ponds, 18 of which are located in Serbia, and 4 in Bosnia and Herzegovina, Republic of Srpska. It has been concluded that both forms of the disease were present in all observed fish ponds. Prevalence of telohanellosis located on the fins ranged between 3% and 30%, and the infection intensity was between 2 and 86 cysts per individual, while in the case of thelohanellosis on scales the values were higher. Changes on the scales were present during April and May, and on the fins during July and August. After determination of morphological characteristics of spores and histopathological characteristics of plasmodia located on the fins and scales, no significant differences were noticed between them. Also, artificial infestation of carp fingerlings for species differentiation was done. Since there are no adequate therapeutic measures, control of thelohanellosis is still based on compliance with basic sanitaryprophylactic measures such as drying of equipment, freezing, mechanical cleaning and disinfection with lime.

Telohaneloza je obolenje koje se javlja kod svih kategorija šarana. Uzročnik je protozoa Thelohanellus nikolskii Achmerov, 1955. Manifestuje se u dva oblika. Prvi se javlja kao telohaneloza na perajima kod jednogodišnjih mladunaca šarana a drugi kao telohaneloza krljušti kod dvogodišnjih, trogodišnjih i višegodišnjih kategorija ribnjačkog šarana (Cyprinus carpio). Istraživanjima koja su trajala u periodu od 2008.-2012. godine obuhvaćeno je 22 ribnjaka od čega se 18 nalaze u Srbiji a 4 u BIH, Republika Srpska. Utvrđeno je da su oba oblika obolenja bila prisutna na svim ispitivanim ribnjacima. Kod telohaneloze na perajima, prevalenca se kretala od 3-30% a intenzitet infekcije od 2-84 cisti po jedinki, dok su te vrednosti kod telohaneloze na krljištima bile veće. Promene na krljuštima bile su prisutne tokom aprila i maja a na perajima tokom jula i avgusta. Utvrđivanjem morfoloških karakteristika spora iz cisti sa peraja i krljušti, kao i prilikom determinacije patohistoloških karakteristika plazmodijuma nisu uočene značajne razlike između njih. Takođe je urađen i ogled veštačkog zaražavanja mladunaca šarana radi diferencijacije vrste. Pošto ne postoji ni jedno adekvatno terapeutsko sredstvo kontrola telohaneloze i dalje se bazira na pridržavanju osnovnih sanitarno profilaktičkih mera kao što su isušivanje objekata, izmrzavanje, mehanička obrada tla i dezinfekcija krečom.