ISSN Versión impresa 2218-6425 ISSN Versión Electrónica 1995-1043

ORIGINAL ARTICLE / ARTÍCULO ORIGINAL

HELMINTHS OF THE NUTRIA MYOCASTOR COYPUS (RODENTIA: MYOCASTORIDAE) IN THE

FOREST OF ARAUCARIAS, BRAZIL

HELMINTOS DE NUTRIA MYOCASTOR COYPUS (RODENTIA: MYOCASTORIDAE) EN LA MATA

DE ARAUCARIAS, BRASIL

Parasitology Laboratory, Federal University of the Fronteira Sul, Campus Realeza, PR, Brazil.

2 Laboratory for Parasitic Diseases of Animals, Department of Preventive Veterinary Medicine and Animal Reproduction,

School of Agrarian and Veterinarian Sciences, Paulista State University (UNESP).

Corresponding author: Fagner Luiz da Costa Freitas, Rua Edmundo Gaievski 1000, Acesso PR 182 km. CEP 85770-000,

Realeza, PR, Brazil. Phone: +55(46)3543 - 8377

E-mail: fagner.freitas@uffs.edu.br

1 2 2

Danise Benati ; Marcela Figuerêdo DuarteMoraes ; Estevam Guilherme Lux Hoppe ; José Hairton ;

Tebaldi

1,*

Iucif Abrão Fagner Luiz da Costa Freitas

Nascif Júnior &

ABSTRACT

Keywords: Brazilian Araucaria Forest – Helminth fauna – Indicators of infection – Neotropical Region – Rodents – Wild

The nutria (Myocastor coypus Molina, 1782) can significantly affect ecosystems, resulting in adverse

socioeconomic and health consequences for humans and animals. The present study identified the

helminth fauna of M. coypus from a region of Mata de Araucaria in the State of Paraná, Brazil. Three free-

living adult males that were found dead in the rural zone of this municipality were used. Anatomical

segments from the digestive tract, respiratory tract, heart and kidneys were sieved and the material was

fixed in Railliet and Henry solution. The helminths were identified and counted and the infection

indicators were analyzed descriptively. A total of 341 helminths was collected belonging to the Orders and

Families Trichostrongylidea: Heligmonelidae; Cestoda: Hymenolepididae; and Digenea: Notocotylidae.

The prevalence, parasite intensity and abundance of the two first helminth species were observed in the

animals evaluated. The region of study represents a new locality record for the three species diagnosed.

Myocastor coypus is a new registered host for Rondentolepis octocoronata Linstow, 1879 in Brazil. These

data contribute to the knowledge of the helminth fauna of free-living M. coypus in the Brazilian Araucaria

Forest region.

Neotropical Helminthology

377

Neotropical Helminthology, 2017, 11(2), jul-dic: 377-386

INTRODUCTION

378

RESUMEN

Palavras clave: Helmintofauna – indicadores de infección – Mata de Araucária Brasileña – Región Neotropical – Roedores – salvaje

La nutria (Myocastor coypus Molina, 1782) puede afectar significativamente los ecosistemas, resultando

en consecuencias socioeconómicas y de salud adversas para los seres humanos y los animales. El presente

trabajo identificó la helmintofauna de M. coypus oriundos de una región de Mata de Araucária en el Estado

de Paraná, Brasil. Se utilizaron tres animales de vida libre, adultos, machos, encontrados muertos en el

área rural del municipio de Dos Vizinhos-PR. Los segmentos anatómicos del tracto digestivo,

respiratorio, cardíaco y renal fueron tamizados y el contenido fijado en solución de Railliet y Henry.

Después de la identificación y recuento de los helmintos, se elaboró un análisis descriptivo de los

indicadores de infección. Se recogieron 341 helmintos, pertenecientes al Orden y Familia:

Trichostrongylidea: Heligmonelidae, Cestoda: Hymenolepididae y Digenea: Notocotylidae. La

prevalencia, intensidad y abundancia parasitaria media de las dos primeras especies de helmintos fueron

las mayores observadas en los animales evaluados. La región de estudio representa un nuevo registro de

localidad para las tres especies diagnosticadas. Myocastor coypus es un nuevo huésped registrado para

Rondentolepis octocoronata Linstow, 1879, en Brasil. Estos datos contribuyen al conocimiento de la

helmintofauna de M. coypus de vida libre en la región de la Mata de Araucária Brasileña.

being part of this ecosystem. Predominates the

subtropical climate, which presents/screens

rigorous winters and hot summers, with rainfall

indexes relatively high and well distributed during

the year (Basso, 2010, IBGE, 2012).

The species of parasites and indicators of parasitic

infection (prevalence, abundance, mean intensity

and variation of intensity) observed in M. coypus

vary according to the geographical region they

inhabit, it is considered that cold temperatures are a

limiting factor for the geographical distribution of

the populations of coypus (Baroch et al., 2002).

Microbial and endoparasite infections can cause

considerable mortality, especially in times of high

population density. Endoparasites rarely kill their

host but may reduce the ability of coypus

populations to slow population growth (Sheffels,

2013; Zanzani et al., 2016).

The helminth fauna of M. coypus has been

described in studies conducted in North America,

Europe and some countries of South America.

Cases of natural infection with the following have

been described: Graphidioides myocastoris

(Babero, 1979), Trichuris myocastoris (Baruš et al.

1975), Dipetalonema sp. (Grassi, 1890),

Hippocrepis myocastoris (Cabello & Kinoed,

1979), Rodentolepis sp. (Yamaguti, 1959),

Heligmosomoides sp. (Büchner, 1889),

Coypus (Myocastor coypus Molina, 1782) are

rodents belonging to the family Capromyidae,

natives to the South America(Woods et al., 1992;

Carter & Leonard, 2002). They live on the banks of

rivers and lakes and are herbivores with nocturnal

habits (Gosling & Baker, 1981; Rodrigues &

Ferigolo, 2004). They are considered opportunistic

animals, known to use different food sources,

depending on the vegetation present in the region,

are general herbivores capable of consuming up to

25% of their body mass daily, using both aquatic

and terrestrial vegetation (Gosling & Baker, 1981;

Christen, 1978; Guichón et al., 2003). They cause

adverse impacts on the ecosystem such as

disruption of ecological processes, competition

with native species for resources and reduction of

biodiversity (Elton, 1958; Mack & D'antonio,

1998).

The Araucaria forest, a typical phytophysiognomy

of the Southern Region of Brazil and also found in

the highest relief points of the Southeastern

Region, whose characteristic species is the Paraná

Pine (Araucaria angustifolia), (IBGE, 2012)

presents remnants dispersed in small capons, some

of which are still conserved characteristics of

primary forest with a flora of Pteridophytes own

Neotropical Helminthology, 2017, 11(2), jul-dic Benati et al.

379

Neotropical Helminthology, 2017, 11(2), jul-dic Helminths of the Myocastor coypus

Strongyloides myopotami (Artigas & Pacheco,

1933), Trichuris sp. (Roederer, 1761), Capillaria

hepatica (Bancroft, 1893), Trichostrongylus

colubriformis (Leiper, 1909), Trichostrongylus sp.

(Leiper, 1909), Trichostrongylus duretteae

(Leiper, 1909), Rodentolepis avetjanae

(Akhumian, 1956), Anoplocephala sp. (Goeze,

1782), Hymenolepis octocoronata (Linstow,

1879), Dicrocoelium lanceolatum (Braun, 1902),

Dicrocoelium sp. (Braun, 1902) and Fasciola

hepatica (Linnaeus, 1758) (Wenzel, 1982; Silva et

al., 2007; El-Kouba, et al., 2009; Guerreiro et al.,

2014). In Brazil, infection by Hippocrepis

fuelleborni (Travassos & Vogelsang, 1930) and

Trichuris travassoi (Linnaeus , 1771) has been

described, along with infection by the protozoa

Giardia sp. (Kunstler, 1882), Cryptosporidium sp.

(Levine, 1984) and Cystoisospora sp. (Frenkel,

1977) (Silva et al., 2007; Sheffels & Sytma, 2007;

Rocha et al., 2012).

Thus, because of the need to expand knowledge

regarding helminth parasites of Myocastor coypus

in Brazil, the present study had the objective of

identifying the helminth fauna of coypus from the

region of Forest in Araucaria.

Study area

The research was conducted in the Araucarias

Forest, located in the southwestern region of the

state of Paraná, between the parallels 25° 44 'and

5°S and the meridians 53°3' and 31º W, in the

municipality of Dois Vizinhos, Paraná, Brazil (Fig.

1).

The Subtropical Forest, also known as Forest in the

Araucaria, Pine tree of Paraná among other names,

has preference in areas of higher altitude (above

500m), where the temperature is milder. Although

Araucaria predominates, other vegetables such as

Imbuia and Mate herb are also associated with it.

Currently it is reduced to approximately 3% of the

initial area (IBGE, 2012).

Animals

In the period from 2013 to 2014, three free-living

male adults (M. coypus) were found dead in the

rural area of the municipality of Dois Vizinhos,

Southwest of the State of Paraná, and donated by

rural producers to the Laboratory of Parasitology

of the Federal University of the Fronteira Sul,

Campus Realeza-PR.

Parasitological methods

The animals were stored in a freezer at -20 °C until

the time of necropsy. Then the specimens were

thawed at room temperature. Necropsies were

performed at the Laboratory of Parasitology of the

Federal University of the Fronteira Sul, Campus

Realeza - PR. The anatomical segments of the

digestive tract (esophagus, stomach, small

intestine and large intestine), along with the

trachea, heart, lung, liver, pancreas and kidneys,

were sectioned separately and the material

obtained was sieved using a Tyler 100 mesh and

was fixed in Railliet & Henry solution, for

subsequent identification of the helminths with the

aid of a stereoscopic microscope.

The helminths were diaphanized in 80% acetic acid

solution and, if necessary, diaphanized in beech

creosote for studies in optical microscopy on

temporary slides. For each species, at least 10

specimens of each sex were measured. In case of

species with few specimens, all specimens

obtained were evaluated. To obtain morphometric

and morphological characteristics, we used a clear

camera equipped microscope and the images of the

specimens obtained with an Olympus BX-51

microscope equipped with a Q-Color 3 digital

camera and the images were processed by the

image analyzer software Image-Pro Plus 4.0 ,

The taxonomic identification of helminths was

made following keys proposed by Linstow (1879),

Travassos & Vogelsang (1930) and Artigas &

Pacheco (1933). After identification and counting

of the helminths, a descriptive analysis of the

infection indicators according to Bush et al. (1997).

Specimens of each species diagnosed were

deposited in the collection of the Laboratory of

Parasitology of the Federal University of the

Fronteira Sul, Campus Realeza-PR.

Ethical issues

This study was approved through the Sistema de

Autorização e Informação em Biodiversidade -

SISBIO (Protocol N°. 45.720) and the Ethics

Committee for Animal Use UFFS/Realeza

(Protocol N°. 23205.005173/2014-81).

MATERIALS AND METHODS

(Adapted from WWF, 2012 and Government of the state of Paraná, 2017).

Figure 1. Map representing the Araucaria Forest in Brazil, highlighting the Municipality of Dois Vizinhos, PR – Brazil.

Neotropical Helminthology, 2017, 11(2), jul-dic

diagnosed. Still, M.coypus is a new registered host

for R. octocoronata in Brazil.

Pudica maldonadoi Artigas & Pacheco, 1933

(Trichostrongyloidea: Heligmonelidae)

Thin, spiraled nematode was attenuated anterior

ending; mouth small, with poorly visible papillae.

Thick cuticle along the body was transversal

striated and in cross-section, at midbody 12

cuticular crests with uniform striations may be

observes. The male body length is 4.98 mm ± 0.40,

width 0.069 mm ± 8.5. The cephalic vesicle is

0.074 mm ± 0.0095, excretory pore is 0.55 mm ±

0.17 (from the anterior ending). Long, and the

esophagus is 0.43 mm ± 0.012, long and the nerve

ring is 0.21 mm ± 0.022. From the anterior ending

the copulatory pouch is asymmetrical, and the thin

spicules are thin, is 0.46 mm ± 0.1 in length. The

female is longer than the male, with total length of

10.5 mm ± 0.06, and 0.11 mm ± 0.008 wide. The

vulva is at 0.13 m ± 0.023, from tail anus. Distance

from the anus to the posterior extremity is 0.05 mm

± 0.026, with simple genital apparatus and acute

conical tail, without a terminal spine. The caudal

RESULTS

A total of 341 specimens of three species

representing the groups Digenea, Cestoidea and

Nematoda were identified. The three species that

were identified as parasitizing M. coypus in the

st ud y ar ea w ere P u d i c a m a l d o n a d o i

(Trichostrongylidea: Heligmonelidae ),

R o d e n t o l e p i s o c t o c o ro n a t a ( Cesto da :

Hymenolepididae) and Hippocrepis fuelleborni

(Diginea: Notocotylidae) (Table 1).

The nematode P. maldonadoi was the most

abundant species among the samples, with the

higher prevalence, mean intensity and abundance

rates. Although it presented the same prevalence as

the cestode R. octocoronata, it was observed that

the latter presented abundance and mean intensity

lower than the former. The digenetic H. fuelleborni

was the species with the lowest descriptions of

infections among the animals evaluated.

The region of study represents a new record of

locality for the three species of helminths

380

Benati et al.

Neotropical Helminthology, 2017, 11(2), jul-dic Helminths of the Myocastor coypus

extremity presents an intumescent cuticle at the

level of the vulva that forms dorsal a foreskin-

shaped fold (Fig. 2).

Taxonomic summary:

Host: Myocastor coypus

Location of infection: Small intestine

Locality: Dois Vizinhos, state of Paraná, Brazil

Prevalence: 100%

Abundance: 65.3 parasites/host

Mean intensity: 65.3 parasites/host

Variation of intensity:11 to 54 parasites

Rodentolepis octocoronata Linstow, 1879

(Cestoidea, Hymenolepididae)

Scolex was four oval suction cups and a face with

eight prominent hooks, meander 0.062 mm in

lenght. The cirrus pouch is perpendicular is the

proglottids. The cirrus is long and tangled. Each

proglottids has a uterus and three well-developed

testicles (Fig. 3).

Taxonomic summary:

Host: Myocastor coypus

Figure 2. Morphology of Pudica maldonadoi: A) Copulatory bursa of the male; B) Anterior extremity; C) Cross-section through

the synlophe. Scale bar: A and C: 50µm, B: 100µm.

381

Table 1. Helminth species and descriptor of infection indicators identied in three adults coypus (Myocastor coypus)

that originated from the municipality of Dois Vizinhos, state of Paraná, Brazil.

Helminths Site of

infection Prevalence

Abundance Mean

intensity

Range of

intensity No

Nematoda

Trichostrongyloidea

Pudica maldonadoi

Small

intestine 100 65.3 65.3 11 -

196

Cestoda

Hymenolepididae

Rodentolepis octocoronata

Small

intestine 100 37 37 24 -

111

Digenea

Notocotylidae

Hippocrepis fuelleborni

Large

intestine

66.6 8 2 2 -12 34

Location of infection: Small intestine

Locality: Dois Vizinhos, state of Paraná, Brazil

Prevalence: 100%

Abundance: 37 parasites/host

Mean intensity: 37 parasites/host

Variation of intensity: 24 to 55 parasites

Hippocrepis fuelleborni Travassos & Vogelsang,

1930 (Digenea, Notocotylidae)

Elongated body was 3.02 mm ± 1.14 in length, the

anterior with is 0.33 mm ± 0.09, becoming widow

at middle is 0.47 mm ± 0.19, and posterior portion

of 0.55 mm ± 0.16. The oral sucker is 0.27 ± 0.08 x

0.29 ± 0.09 mm was the presence of ventral

papillae. Pharynx absent and esophagus short.

Male reproductive system with presence of

elongated cirrus pouch, with small spines

measuring 0.49 mm ± 0.16 in length. The testicules

are lobates and displace diagonary. The left testicle

is 0.23 ± 0.14 x 0.22 ± 0.16 mm and the right

testicle is 0.21 ± 0.18 x 0.25 ± 0.15 mm. The

insertion ceca join together in the end portion

between the testicles. The female reproductive

system is formed by a well-developed uterus and

pre-testicular ovary of 0.17 ± 0.13 x 0.16 ± 0.14

mm (Fig. 4).

Taxonomic summary:

Host: Myocastor coypus

Location of infection: Large intestine

Locality: Dois Vizinhos, state of Paraná, Brazil

Prevalence: 66.6%

Abundance: 8 parasites/host

Mean intensity: 12 parasites/host

Variation of intensity: 2 to 22 parasites

Neotropical Helminthology, 2017, 11(2), jul-dic

Figure 3. Morphology of Rodentolepis octocoronata: A) Presence of eight thorns; B) Immature proglottid. Scale bar: A: 50µm,

B: 250 µm.

382

Benati et al.

Neotropical Helminthology, 2017, 11(2), jul-dic Helminths of the Myocastor coypus

Figure 4. Hippocrepis fuelleborni: A) and C) Posterior extremity – reproductive system; B) Anterior extremity. Scale bar: A and

B: 300µm, C: 500 µm.

383

Artigas, P & Pacheco, G. 1933. Longistriata

m a l d o n a d o i n . s p . ( N e m a t o d a :

Trichostrongylidae) parasite of Myocastor

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Babero, BB & Lee, J W. 1961. Studies on the

helminths of nutria, Myocastor coypus

(Molina), in Louisiana with check-list of

other worm parasites from this host. Journal

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Poché, RM. 2002. Nutria (Myocaster

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BIBLIOGRAPHIC REFERENCES

Graphidioides myocastoris and Trichuris

myocastoris. However, in Argentina, the most

prevalent digenean found in coypus was Fasciola

hepatica (Artigas & Pacheco, 1933). It is important

to emphasize that the helminths identified in M.

coypus in the municipality of Dois Vizinhos,

Paraná, were specific parasites for this host. There

are still no records in the literature regarding the

presence of these helminths parasitizing other

species of mammals.

The helminthological fauna of M. coypus reported

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parasites for this host, including 11 species of

digeneans, 21 species of cestodes, one species of

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(Babero & Lee, 1961). However, in the present

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This variation of diversity and prevalence of

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This study describes the helminths of coypus

(Myocastor coypus) in the municipality of Dois

Vizinhos, Paraná, Brazil. These data contribute to

the knowledge of the helminth fauna of wild M.

coypus in the primary habitat of this species and

octocoronata in coypus in Brazil.

Neotropical Helminthology, 2017, 11(2), jul-dic

DISCUSSION

The nematode P. maldonadoi was the most

abundant species among the samples, with the

higher prevalence, mean intensity and abundance

rates. Although it presented the same prevalence as

the cestode R. octocoronata, it was observed that

the latter presented lower abundance and mean

intensity. The digenean H. fuelleborni was the

species with the lowest descriptors of infection

among the animals evaluated. The region of study

represents a new locality record for the three

parasite species diagnosed. Nevertheless,

M.coypus is a new host record for R. octocoronata.

Higher prevalence of nematodes than of other

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