ORIGINAL ARTICLE /ARTÍCULO ORIGINAL
LERNAEOSIS IN CNESTERODON DECEMMACULATUS (CYPRINODONTIFORMES,
POECILIDAE) AND OBSERVATIONS ON THE LETHAL EFFECT IN SMALL SIZED
SPECIES OF HOSTS
LERNEOSIS EN CNESTERODON DECEMMACULATUS (CYPRINODONTIFORMES,
POECILIDAE) Y OBSERVACIONES SOBRE EL EFECTO LETAL SOBRE ESPECIES
HOSPEDADORAS DE PEQUEÑA TALLA
Laboratoriode Patología de Organismos Acuáticos de Interés Comercial. Universidad Nacional del Sur,
Bahía Blanca, Argentina. E-mail: sguaglia@criba.edu.ar
Neotropical Helminthology, 2016, 10(2), jul-dic: 275-280.
ABSTRACT
Keywords: Lernaea cyprinacea – Cnesterodon decemmaculatus – Fish pathology
Lernaea cyprinacea is one of the best known species of the genus, with a wide global distribution,
that causes lesions on the skin of fresh water fish fostering secondary infections. The aim of the
present study was to record the presence of L. cyprinacea on Cnesterodon decemmaculatus and
to study the lethal effect of this copepod on a host species of small size. The specimens were
parasitized by post-metamorphic stages of females. The ulcerous lesions rapidly became
contaminated with dense Saprolegnia sp. mycelia and they were associated with Epistylis sp., a
ciliated peritrichid. Histological examination showed invasion of the visceral mass which
exerted mechanical compression on the muscle, kidney, spleen and gonad. Fibrous encapsulation
and inflammatory infiltrate were observed as a response. The intense visceral invasion provoked
in C. decemmaculatus in the reproductive stages makes the fish potentially susceptible to lethal
consequences, with consequent damage at the population level.
275
ISSN Versión impresa 2218-6425 ISSN Versión Electrónica 1995-1043
Silvia Guagliardo & Daniel Tanzola
RESUMEN
Palabras clave: Lernaea cyprinacea - Cnesterodon decemmaculatus - Patología de peces
Lernaea cyprinacea es una de las especies mejor conocidas del género, con una distribución
mundial, que causa lesiones en la piel de los peces de agua dulce promoviendo infecciones
secundarias. El objetivo del presente estudio fue registrar a L. cyrpinacea en Cnesterodon
decemmaculatus y estudiar el efecto letal de éste copépodo en una especie de hospedador de
pequeña talla. Los especímenes estuvieron parasitados por hembras post-metamórficas. Las
lesiones ulcerativas rápudamente se contaminaron con densos micelios de Saprolegnia sp.
asociados con el ciliado peritrichido Epistylis sp. El examen histológico mostró invasión de la
masa visceral el cual ejerció compression mecánica sobre el músculo, el riñón, el bazo y las
gónadas. Se observó una respuesta de encapsulación fibrosa e infiltrado inflamatorio. La intensa
invasión visceral de C. decemmaculatus en estados reproductivos torna al pez potencialmente
susceptible a consecuencias letales con el perjuicio consecutivo a nivel poblacional.
276
Neotropical Helminthology. Vol. 10, Nº2, jul-dic 2016
One hundred and eighteen adults of
Cnesterodon decemmaculatus (62 females and
56 males) from an urban lake in Bahía Blanca,
Argentina (38º41'S; 62º15'W) were examined
during March and April 2012. They were
between 23-34 mm (Mean= 28; Standard
deviation= 3.02) in size and had a total weight
between 0.227-0.277 g (Mean= 0.250;
Standard deviation= 0.018). A hand net was
used to catch the fish which were then kept in
an aerated aquarium at 18-20°C and fed with
fish food. The external areas of the body
examined were skin, eyes and fins. The :
parasitized fish were fixed in 10% formalin,
transverse sections in series (5 μm thick) were
made of the whole body and stained with
hematoxylin and eosin (HE) and Masson
trichrome.
The specimens were parasitized by post-
metamorphic stages of females of L.
cyprinacea. They were identified by
morphological features such as the structure of
antennae, maxillae, maxillipeds and
thoracopods. The site of anchorage of the
copepods varied between dorsal (8/19), anal
(9/19) and left pectoral fins (2/19) (Figures 1a
and 1b). The prevalence of infection was
19.1% and the mean intensity 1. Ulcerative
lesions were rapidly contaminated with dense
mycelia of Saprolegnia sp. that invaded the
external integument and the scale sack. Dense
colonies of Epistylis sp (ciliated peritrichids)
and Gomphonema spp (diatoms) were fixed to
the external segment of the neck of L.
cyprinacea.
The histological examination showed that the
whole visceral mass of the fish was invaded.
Figures 2 illustrate the anchor apparatus
Cnesterodon decemmaculatus, , Jenyns, 1842
is one of the small species of the Argentine
ichthyofauna. They live in shallow pools and
streams from the south of Brazil to Río Negro
(Lucinda, 2005). Until now it was not known
as a host to Lernaea cyprinacea Linnaeus,
1758 (Copepoda, Cyclopoida), a species
introduced accidentally in South America via
the Cyprinids (Piasecki et al., 2004). Records
of anchor worms in Argentina are occasional
(Paggi, 1972, 1976; Ortubay et al., 1994; Roux
et al., 2000; Vanotti and Tanzola, 2005,
Mancini et al., 2006, 2008; Plaul et al., 2010).
Lernaea cyprinacea is one of the best known
species in the genus, with the widest global
distribution, that causes skin lesions on fresh
water fish. Cases have been reported of
secondary infections in unsuitable water
conditions (Carnevia & Speranza, 2003;
Mancini et al., 2008, Bednarska et al., 2009).
Among the lesions caused by different species
of Lernaea the following are mentioned:
disruption of the dermis and epidermis,
hyperplasia, acute and chronic inflammation,
granuloma formation, fibrotic encapsulation,
ulceration and necrosis, and the following cell
types of the immune response are observed:
neutrophils, lymphocytes and eosinophilic
granule cells (ECGs). Fish mortality appears to
be related to the size of the fish (Sharif &
Roberts, 1989; Paperna, 1996; Mancini et al.,
2008).
The objective of the present study is to record
the presence of L. cy prinacea in C.
decemmaculatus and to study the lethal effect
of this copepod on a small sized host species.
They have not experimented with live animals,
not affected population parameters of the host
or provoked impacts on the environment and
human health or animal.
INTRODUCTION MATERIALS AND METHOD
RESULTS
Guagliardo & Tanzola
277
Neotropical Helminthology. Vol. 10, Nº2, jul-dic 2016
congestion or hemorrhagic areas in the visceral
mass were observed. All the parasitized fish
became emaciated and died at the end of three
weeks. In contrast, there was 100% survival in
another fish group without parasites
maintained in the same conditions.
(arrows) of the parasite invading internal
organs and exerting mechanical compression
on the muscle and kidney. The fish developed a
strong fibrotic response around the horns of the
an ch or. Fi gu re 3 sh ow s i n f il tr at ed
inflammatory tissue around the parasite,
severe compressive atrophy in the spleen. No
Figure 1. Lernaea cyprinacea (in situ) parasitising Cnesterodon decemmaculatus. a) Ventral location of anchorage; b) Dorsal fin
affected, observed the heavy colonization by micelia of Saprolegnia sp., Epystilis sp. and Gomphonema sp. (Scale-bar= 10mm)
Figure 2. Transverse section of Cnesterodon decemmaculatus showing two sections (arrows) of the anchorage aparatus (horns)
exerting mechanical compression on the muscle and kidney and a strong fibrosis arround the visceral mass (Scale-bar= 0.1mm)
Lernaeosis in Cnesterodon
278
fish, which appears to be the maximum
permitted number considering the body mass
ratio between parasite and host.
El-Mansy (2009) showed that specimens of
Carassius auratus Linnaeus, 1758 infected by
Lernaea were stressed, exhausted, lost scales
and stopped feeding. They showed oedema in
the anchorage point, hemorrhage, fibrotic
reaction around the parasite, leukocyte
infiltration, necrosis and ulcerative areas
especially on the base of the fins. There are
numerous reports of the presence of
eosinophilic granular cells (EGCs), but it is
still not clear what role they play in the
inflammatory processes (Sharif & Roberts,
1989; Silva-Souza et al., 2000; Wojciech et al.,
2004). In the present study, mononuclear
infiltrates predominated around the parasite.
Essa et al. (2003) demonstrated the deleterious
effect of increased cortisol levels in the grass
carp, Ctenopharyngodon idella Steindachner,
1866 parasitized by L. cyprinacea.
Lernaea cyprinacea is a cosmopolitan species
and one of the freshwater fish ectoparasites
with lower host specificity. To the present, it
has been recorded in 16 fish species in
Argentina (Mancini et al., 2008; Plaul et al.,
2010). This is the first record of L. cyprinacea
in C. decemmaculatus. All parasitic females
were ripped, coincident with the season of
previous records in the literature (end of
summer). In respect to the site of location on
the host, the following points of insertion were
reported in the literature: the base of the dorsal
and pectoral fins and the middle part of the
b o d y ( i n O d o n t e s t h e s b o n a r i e n s i s
(Valenciennes, 1835)), the caudal peduncle (in
Rhamdia quelen (Quoy & Gaimard, 1824)) or
without any preferred site in Oligosarcus
jenynsii (Günther, 1864) (Mancini et al.,
2008). In the present study the invaded zones
were the base of the dorsal, anal and left
pectoral fins. Only one copepod was found per
DISCUSSION
Figure 3. Transverse section of Cnesterodon decemmaculatus showing severe compressive atrophy in the spleen (arrow) (Scale-
bar= 0.1mm)
Neotropical Helminthology. Vol. 10, Nº2, jul-dic 2016 Guagliardo & Tanzola
279
Sometimes infected fish were noted scratching
on the walls of the tank (Sharif & Roberts,
1989). In the hosts studied in captivity a
progressive loss of condition and positive
response to feeding was observed. After three
weeks 100% lethality was recorded compared
to another group kept without parasites.
Considering the parasitic prevalence (P) and
intensities (I) documented for Argentine fish,
the estimates in this study can be classified as
moderated (P=19%; I= 1) compared to 53.6%
in O. bonariensis; 80.9% in O. jenynsii and
100% in Cyprinus carpio, among others.
Paperna (1996) indicated that lernaeosis in fish
smaller than 40 mm is lethal. The heavy
invasion in the visceral mass of C.
decemmaculatus makes the fish potentially
susceptible of suffering lethal consequences in
the reproductive stage, with consequent
negative effect at population level, considering
that the standard length recorded for this
species varies between 38 mm (Ringuelet et
al., 1967), and 35 mm (males) and 45 mm
(females) (Lucinda, 2003).
The authors wish to thank Rosemary Scoffield
for her review of the English version.
ACKNOWLEDGMENTS
Bednarska, M, Bednarski, M, Soltisyak, Z &
Polechonski, R. 2009. Invasion of
Lernaea cyprinacea in rainbow trout
(Onchorhyn c hu s myki s s). Acta
Scientiarum Polonorum., Medicina
Veterinaria, vol. 8, pp. 27-32.
Carnevia, D & Speranza, G. 2003. First report
of L. cyprinacea L., 1758 in Uruguay
introduced by goldfish C. auratus (L.,
1758) and affecting axolotl Ambystoma
BIBLIOGRAPHIC REFERENCES
mexicanum. Bulletin of the European
Association of Fish Pathologists, vol. 23,
pp. 255-256.
El-Mansy A. 2009. On the occurrence of adult
females of Lernaea species (Crustacea:
Copepoda) parasitic on gold fish
Carassius auratus (Linnaeus) in some
commercial aquaria in Egypt. Egypt
Journal of Aquatic Biology and
Fisheries, vol. 13, pp. 7-36.
Essa, M, Abd El-Galil, M, Mousa, W &
Ibrahim S. 2003. Verification of the
deleterious effects of Lernaeosis on the
health of grass carp (Ctenopharyngodon
idella). Egypt Journal of Aquatic
Biology and Fisheries, vol. 7, pp. 241-
261.
Lucinda, 2003. Poeciliidae (Livebearers). p.
555-581. In R.E. Reis, S.O. Kullander
and C.J. Ferraris, Jr. (eds.) Checklist of
the Freshwater Fishes of South and
Centr al Ameri ca. Po rto Alegre:
EDIPUCRS, Brazil.
Lucinda P. 2005. Systemmatics of genus
C n e s t e r o d o n G a r m a , 1 8 9 5
(Cyprinodontiformes: Poeciliidae:
Poeciliinae). Neotropical Ichthyology,
vol. 3: pp. 259-270.
Mancini, M, Rodríguez, C, Prosperi, C,
Salinas, V & Bucco, C. 2006. Main
diseases of pejerrey (Odontesthes
bonariensis) in central Argentina.
Pesquisa Veterinaria Brasileira, vol. 26,
pp. 205-210.
Mancini, M, Rodríguez, C, Ortiz, M, Salinas,
V & Tanzola, R. 2008. Lerneosis en
peces silvestres y cultivados del Centro
de Argentina. Biología Acuática, vol. 24,
pp. 33-41.
Ortubay, S, Semenas, L, Ubeda, C, Quagliotto,
A & Viozzi, G. 1994. Catálogo de peces
dulceac uícolas d e la Pat agonia
Argentina y sus parásitos metazoos.
Dirección de Pesca, Subsecretaría de
Recursos Naturales. Río Negro, 108 pp.
Paggi, J. 1972. Contribución al conocimiento
d e l o s L e r n a e i d a e ( C r u s t a c e a ,
Neotropical Helminthology. Vol. 10, Nº2, jul-dic 2016 Lernaeosis in Cnesterodon
280
deportiva del río Paraná Superior
(tramo Ituzaingo – Ita Ibate, Corrientes,
Argentina). Comunicaciones Científicas
y Tecnológicas. Universidad Nacional
del Nordeste, Corrientes, 3 pp.
Silva-Souza, A, Almeida, S & Machado P.
2000. Effect of the infestation by Lernaea
cyprinacea Linnaeus, 1758 (Copepoda,
Lernaidae) on the leucocytes of
Schizodon intermedius Garavello &
B r i t s k i , 1 9 9 0 ( O s t e i c h t h y e s ,
Anostomidae). Revista Brasileira de
Biología, vol. 60, pp. 217-220.
Sharif, M & Roberts, R. 1989. Th e
experimental histopathology of Lernaea
polymorpha Yu, 1938 infection in naïve
Aristichthys nobilis (Richardson) and a
comparison with lesion in naturally
infected clinically resistant fish. Journal
of Fish Diseases, vol. 12, pp.405-414.
Vanotti, M & Tanzola R. 2005. Relación entre
la carga parasitaria total y algunos
parámetros hematológicos de Rhamdia
sapo Val. (Pisces) en condiciones
naturales. Biología Acuática, vol. 22,
pp. 249-258.
Wojciech, P, Goodwin, A & Eiras, J. 2004.
Importance of Copepoda in fresh water
Aquaculture. Zoological Studies, vol.
43, pp. 193-205.
Copepoda) de Argentina. Lernaea
argentinensis sp. nov. y Taurocheros
salminisii Brian 1924, parásitos de
peces del río Paraná. Acta Zoológica
Lilloana, vol.29, pp. 35-46.
Paggi, J. 1976. Una nueva especie de
Copepodo Lerneido, Taurocheros
tarangophilus sp. nov., parásita de
Hoplias malabaricus (Bloch, 1974)
hallada en el río Paraná. Physis, vol. 35,
pp. 113-119.
Paperna, I. 1996. Parasites, infections and
diseases of fishes in Africa. An Update.
CIFA Technical Paper 31. FAO. Rome.
220 pp.
Piasecki, W, Goodwin, A, Eiras, J & Nowak, B.
2004. Importance of Copepoda in
freshwater Aquaculture. Zoological
Studies, vol. 43, pp. 193-205.
Plaul, S, García Romero, N & Barbeito, C.
2010. Distribution of the exotic parasite,
Lernaea cyprinacea (c op e p o da ,
Lernaeidae) in Argentina. Bulletin of the
E u r o p e a n A s s o c i a t i o n o f F i s h
Pathologists, vol. 30, pp. 65-73.
Ringuelet, RA, Aramburu, RH & Aramburu,
AA de. 1967. Los peces argentinos de
a g u a d u l c e . C o m i s i ó n d e
Investigaciones Científicas de la
Provincia de Buenos Aires, La Plata,
Argentina, 602 pp.
Roux, J, Tocalino, P, González, A, Sánchez, S
& Bechara, J. 2000. Parásitos externos
de peces de importancia comercial y/o
Received August 9, 2016.
Accepted October 6, 2016.
Neotropical Helminthology. Vol. 10, Nº2, jul-dic 2016 Guagliardo & Tanzola
