Fish Pathology and Parasitology Research Team

We study the parasitic, bacterial and viral diseases of cultured and natural water fish species by pathological, histological and molecular biological methods.

Scientific advisor, research team leader: 
In conformity with the traditions of our research group, we primarily pursue fish parasitology research. During that activity, we regularly check fish species living in Lake Balaton and its tributaries for parasitic infections. We strive to identify the developmental stages of myxosporean parasites and digenetic trematode species in both definitive and alternate hosts (oligochaete worms, freshwater molluscs). We study the occurrence, phylogenetic relations and development of these parasites and the diseases caused by them by the combined use of experimental, histological and molecular techniques.
In collaboration with researchers from several European countries, in the framework of a Horizon 2020 project we are participating in current research on common carp parasites and in addressing fish parasitological problems arising in Hungarian fish farms.
In the framework of our recently started bacteriological research activities our aim is to survey the occurrence of pathogens (Aeromonas, Flavobacterium) causing ulcerative dermatitis in Hungarian fish species. The isolated strains are typed and subjected to antibiotic susceptibility testing. We attempt to detect and isolate fish-pathogenic mycoplasmas and mycobacteria, as well as Chlamydia-like organisms causing epitheliocystis.
So far our virological work has focused primarily on fish circoviruses, but with the introduction of new virus isolation techniques we will have a possibility to identify fish pathogens of hitherto unclarified but presumably viral nature.

Members of the Research Group regularly give expert advice on fish health and primarily fish parasitological issues to Hungarian and international representatives of the fishery sector.

Selected publications: 

Molnár K, Gibson DI, Majoros G, Székely C, Sándor D, Cech G (2016) Malformations of the gill filaments of the ruffe Gymnocephalus cernuus (L.) (Pisces) caused by echinostomatid metacercariae. Journal of Fish Diseases. online first. doi:10.1111/jfd.12469

Székely C, Borkhanuddin MH, Cech G, Kelemen O, Molnár K (2014) Life cycles of three Myxobolus spp. from cyprinid fishes of Lake Balaton, Hungary involve triactinomyxon-type actinospores. Parasitology Research 113: 2817-2825. doi: 10.1007/s00436-014-3942-5

Rangel LF, Santos MJ, Cech G, Székely C (2009) Morphology, molecular data and development of Zschokkella mugilis (Myxosporea, Bivalvulida) in a polychaete alternate host, Nereis diversicolor. Journal of Parasitology 95: 561-569. doi: 10.1645/GE-1777.1

Székely C, Hallett SL, Atkinson SD, Molnár K (2009) Complete life cycle of Myxobolus rotundus (Myxosporea: Myxobolidae), a gill myxozoan of common bream Abramis brama. Diseases of Aquatic Organisms. 85: 147-155. doi: 10.3354/dao02068

Székely C, Shaharom-Harrison F, Cech G, Ostoros, G, Molnár K (2009) Myxozoan infections in fishes of the Tasik Kenyir Water Reservoir, Terengganu, Malaysia. Diseases of Aquatic Organisms. 83: 37–48. doi: 10.3354/dao01991

Palstra AP, Heppener DFM, van Ginneken VJT, Székely C, van den Thillart GEEJM (2007) Swimming performance of silver eels is severely impaired by the swim-bladder parasite Anguillicola crassus. Journal of Experimental Marine Biology and Ecology. 352: 244-256. doi: 10.1016/j.jembe.2007.08.003

Andree KB, Székely C, Molnár K, Gresoviac SJ, Hedrick RP (1999) Relationships among members of the genus Myxobolus (Myxozoa : Bilvalvidae) based on small subunit ribosomal DNA sequences. Journal of Parasitology. 85: 68-74. doi: 10.2307/3285702

Székely C, El-Mansy A, Molnár K, Baska, F (1998): Development of Thelohanellus hovorkai and Thelohanellus nikolskii (Myxosporea: Myxozoa) in oligochaete alternate hosts. Fish Pathology. 33: 107-114. doi: 10.3147/jsfp.33.107

Molnár K, Baska F, Csaba G, Glávits R, Székely C (1993) Pathological and histopathological studies of the swimbladder of eels Anguilla anguilla infected by Anguillicola crassus (Nematoda, Dracunculoidea). Diseases of Aquatic Organisms. 15: 41-50. doi: 10.3354/dao015041

Székely C, Molnár K (1987) Mebendazole is an efficacious drug against pseudodactylogyrosis in the european eel (Anguilla anguilla). Journal of Applied Ichthyology-Zeitschrift für Angewandte Ichthyologie. 3: 183-186. doi: 10.1111/j.1439-0426.1987.tb00539.x

National and international cooperations: 
Georgikon Faculty, Pannon University, Keszthely, Hungary (Festetics Doctoral School)
Department of Parasitology and Zoology, University of Veterinary Medicine, Budapest, Hungary
Faculty of Agriculture and Environmental Sciences, Szent István University, Gödöllő, Hungary (Bioclimate)
Laboratory of Parasitology, Fish and Bee Diseases, Veterinary Diagnostic Directorate, National Food Chain Safety Office, Budapest, Hungary (NÉBIH ÁDI)
National Agricultural Research and Innovation Centre, Research Institute for Fisheries and Aquaculture (NAIK HAKI), Szarvas,Hungary
Balaton Limnological Institute, Centre for Ecological Research, Hungarian Academy of Sciences, Tihany, Hungary (Balaton research)
Semmelweis University, Budapest, Hungary (Bioclimate)
Budapest University of Technology and Economics, Budapest, Hungary (Bioclimate)
Hungarian fish farms (including BH Nonprofit Co. Ltd., Aranyponty Co. Ltd.)
In the Horizon 2020 ParaFishControl project, 29 European institutions involved in fish parasitological research (Consortium Leader: CSIC, Instituto de Acuicultura, Torre de la Sal)
Faculty of Biological Sciences, University of Porto, Porto, Portugal
University Malaysia Terengganu (UMT), Terengganu, Malaysia
Huazhong Agricultural University and Institute of Hydrobiology, Wuhan, China
Ch. C. Singh University, Meerut, U.P., India
Retired researcher, emeritus scientific advisor: 
Assistant research fellow(s): 
Technical engineer: