Research Note - Some Trematode, Nematode, and Acanthocephalan Parasites of Rainbow Trout, Oncorhynchus mykiss, Introduced into Chile

3 Pages·1995·0.43 MB·English

by  Torres, P

J. Helminthol. Soc. Wash.
62(2), 1995, pp. 257-259
Research Note
Some Trematode, Nematode, and Acanthocephalan Parasites of
Rainbow Trout, Oncorhynchus mykiss, Introduced into Chile
PATRICIO TORRES
Institute de Parasitologia, Universidad Austral de Chile, Valdivia, Chile
ABSTRACT: The gastrointestinal tracts of 211 adult Maihue (40°15'S,72°02'W/33/28.1 ± 7.4), Ran-
Oncorhynchus mykiss (Walbaum, 1792) were exam- co (40°11'S, 72°22'W/30/27.2 ± 7.4), Villarrica
ined for trematode, nematode, and acanthocephalan
(39°13'S, 72°06'W/29/29.4 ± 5.2), Caburga
parasites from 8 lakes in southern Chile (between 41 °0 5'
and 39°03' south latitude). The parasites Derogenes (39°06'S, 71°45'W/27/33.8 ± 4.7), and Colico
patagonicus, Acanthostomoides apophalliformis, Ca- (39°03'S, 7 l°59'W/21/29.4 ± 7.6). Dead fish were
mallanus corderoi, Hysterothylacium sp., Acantho- kept at 4°C and examined within 72 hr of col-
cephalus tumescens, and Acanthocephalus sp. were
lection. Procedures of host necropsy, fixation,
present. Camallanus corderoi and D. patagonicus were
staining, and/or clearing of parasites followed
present in 8 and 6 lakes, respectively. In 6 lakes, the
prevalence was higher for C. corderoi compared to 2 those of Torres et al. (1990a, 1992). The defi-
other lakes. In 3 different lakes, the mean intensities nitions of prevalence, mean intensity, and lo-
were higher for D. patagonicus (Lakes Rupanco, Puye- cality adhere to Margolis et al. (1982). Repre-
hue, and Maihue) and C. corderoi (Lakes Ranco, Col-
sentative helminths were deposited in the Col-
ico, and Caburga) with respect to other species. Acan-
thocephalans were infrequent in rainbow trout, except lection of the Institute of Parasitology, Univer-
for A. tumescens in Lake Villarrica. sidad Austral de Chile: Derogenes patagonicus
KEY WORDS: Trematoda, Derogenes patagonicus, (IPUAT 233-236), Camallanus corderoi (IPUAT
Acanthostomoides apophalliformis, Nematoda, Ca-
237-241), Acanthocephalus tumescens (IPUAT
mallanus corderoi, Hysterothylacium sp., Acanthoce-
242-243), Acanthocephalus sp. (IPUAT 244),
phala, Acanthocephalus tumescens, Acanthocephalus
sp., Salmonidae, Oncorhynchus mykiss, prevalence, in- Hysterothylacium sp. (IPUAT 245), and Acan-
tensity. thostomoides apophalliformis (IPUAT 246).
The prevalence and mean intensity of the 6
The successful introduction of salmonids into helminth species in rainbow trout from 8 lakes
Chile was carried out from Hamburg in 1905 are given Table 1. The taxa consisted of 2 trem-
(Golusda, 1927), and their production in fish atode species, Derogenes patagonicus (Szidat,
hatcheries has undergone an important devel- 1956) and Acanthostomoides apophalliformis
opment since 1981 (Alvarado et al, 1990). Re- Szidat, 1956; 2 nematode species, Camallanus
search on the parasitic helminths of wild salmo- corderoiTorres, Teuber, and Miranda, 1990, and
nids is important because of zoonotic implica- Hysterothylacium sp.; and 2 acanthocephalan
tions, damage to fish tissues, potential risk of species, Acanthocephalus tumescens (Linstow,
transmission to fish hatcheries, and impact on 1896) and Acanthocephalus sp. Derogenes pa-
the tourist activity in the lake region of southern tagonicus was found in the stomach, whereas the
Chile (Wetzlar, 1979; Torres et al., 1989). This other species occurred in the intestine. All hel-
note presents information on the prevalence and minth species are first records for rainbow trout
mean intensity of 6 helminth species in the gas- in the lakes studied.
trointestinal tract of rainbow trout, from 8 lakes The specimens of D. patagonicus, Acantho-
in southern Chile, where no previous records have cephalus sp., and A. tumescens were represented
been made of these parasite groups. by adults, sometimes gravid worms, and juve-
Between 1989 and 1990, 211 adult rainbow niles. The specimens of C. corderoi were adults
trout (Salmonidae), were examined. They were and fourth-stage larvae (L4s). The only speci-
caught with 5-, 10-, and 20-mm mesh gill nets mens of A. apophalliformis and Hysterothyla-
in the following lakes (geographic locality/num- cium sp. were a gravid adult and a male, respec-
ber of fish/standard length in centimeters [x ± tively.
SD]): Todoslos Santos (41°05'S, 72°15'W/14/30 Three helminth taxa of various assemblages
± 6.2), Rupanco (40°46'S, 72°30'W/27/32.3 ± were present in rainbow trout from 6 of the 8
7.3), Puyehue(40°36'S, 72°26'W/30/29.2 ± 6.5), lakes, with the exception of Lakes Caburga and
257
Copyright © 2011, The Helminthological Society of Washington
258 JOURNAL OF THE HELMINTHOLOGICAL SOCIETY OF WASHINGTON, 62(2), JUL 1995
Puyehue, where 1 and 2 species, respectively, Table 1. Prevalence and mean intensity of helminth
were recorded. Camallanus cordewiwas the only parasites from Oncorhynchus mykiss in 8 lakes from
southern Chile.
parasite infecting rainbow trout from all 8 lakes,
whereas D. patagonicus was found in 6 lakes.
No.
In the majority of lakes, the prevalence was
infected
higher for C. corderoi compared to Lakes Ru- fishes Mean
panco and Todos los Santos. The mean inten- Lake (% preva- intensity
Helminth taxon lence) (maximum)
sities were higher for D. patagonicus in Lakes
Rupanco, Puyehue, and Maihue compared to 5
Caburga (27)*
other lakes and C. corderoi in Lakes Ranco, Ca- Camallanus corderoi 2(7) 10.5 (17)
burga, and Colico. The mean intensity of A. tu-
Colico (21)
mescens was highest in Lake Villarrica.
Derogenes patagonicus 2(10) 2.5 (3)
Camallanus corderoi was described in perch Camallanus corderoi 6(29) 8.3 (27)
trout, Percichthys trucha, in the Valdivia River Acanthocephalus sp. 3(14) 2.3 (5)
basin, Chile (Torres et al., 1990b). Later, it was Maihue (33)
recorded in wild-introduced salmonids, O. my- Derogenes patagonicus 5(15) 15.4(58)
kiss, and brown trout, Salmo trutta, in the same Camallanus corderoi 9(27) 5.9 (25)
basin (Torres et al., 199la) and in rainbow trout Acanthocephalus tumescens 5(15) 1.8 (3)
cultured in Lake Puyehue (Torres et al., 1993). Puyehue (30)
Analysis of the diet of wild salmonids suggests Derogenes patagonicus 10(33) 82.8 (280)
that the transmission of C. corderoi is augmented Camallanus corderoi 14(47) 23.6(101)
by the frequent consumption of other autoch- Ranco (30)
thonous plankton-eating fishes (especially Gal- Camallanus corderoi 6(20) 9.8(31)
axias spp.), which harbor L4s and immature Acanthocephalus tumescens 4(13) 5.8 (10)
Hysterothylacium sp. 1(3) 1.0
adults (Torres et al., 1991 a). Derogenes patagon-
icus was described by Szidat (1956) in P. trucha Rupanco (27)
in the Argentinian Patagonia. In Chile, D. pa- Derogenes patagonicus 13(48) 24.7 (85)
Acanthostomoides apophalliformis 1 (4) 1.0
tagonicus has been recorded in O. mykiss and S.
Camallanus corderoi 12(44) 12.3(89)
trutta in Lakes Yelcho (43°16'S, 72°15'W) and
Todos los Santos (14)
Tagua Tagua (41°39'S, 72°09'W) (Torres et al.,
Derogenes patagonicus 1 (7) 1.0
1992).
Camallanus corderoi 1 (7) 1.0
Acanthocephalus tumescens was described by
Acanthocephalus sp. 4(29) 1.5(2)
Linstow (1896) from the Patagonian pejerrey,
Villarrica (29)
Atherinichthys microlepidotus, from Argentina.
Derogenes patagonicus 1(3) 2.0
Simultaneous infections by A. tumescens and
Camallanus corderoi 16(55) 10.9 (49)
Acanthocephalus sp. were not observed in rain- Acanthocephalus tumescens 6(21) 22.2(120)
bow trout. Acanthocephalus tumescens occurred
* Number of fishes examined.
only in rainbow trout from Lakes Maihue, Ran-
co, and Villarrica. The mean intensity of Acan-
thocephalus spp., in general, was low, except in trout from Chile. Torres et al. (1992) reported
Lake Villarrica, where A. tumescens had a mean that this species had a low intensity (1-3) in brown
intensity of 22.2. trout and perch trout in Lakes Yelcho and Tagua
Acanthocephalus tumescens and Acanthoceph- Tagua, respectively.
alus sp. have been recorded in rainbow trout, Acanthostomoides apophalliformis was de-
brown trout, puye, and southern smelt, Aplochi- scribed by Szidat (1956) in perch trout in Lake
ton taeniatus, in Lake Yelcho (Torres et al., 1992). Pellegrini, located in the Argentinian Patagonia.
Acanthocephalus sp. has also been recorded in In Chile, it was recorded in perch trout from Lake
P. trucha from Lake Tagua Tagua (Torres et al., Tagua Tagua with a prevalence of 45% and a
1992). mean intensity of 38. Their metacercariae have
The presence of A. apophalliformis and Hys- been observed in the liver of puye and juvenile
terothylacium sp. in rainbow trout from Lakes southern smelt in Lakes Yelcho and Tagua Tagua
Rupanco and Ranco, respectively, seems to be (Torres et al., 1992).
"accidental" by low prevalence. Hysterothyla- The 6 helminth species infecting rainbow trout
cium sp. is recorded for the first time in rainbow in the present study have been found previously
Copyright © 2011, The Helminthological Society of Washington
RESEARCH NOTES 259
in autochthonous Chilean fishes (Torres et al., gonischen Gewasser und die Beziehungen des
1990a, b, 1992). These fishes act as reservoirs Wirtsfisches und seiner Parasiten zur palaarktisch-
en Region. Archiv fur Hydrobiologie 51:542-577.
from which infections have apparently devel-
Torres, P., X. Cabezas, J. Arenas, J. C. Miranda, C.
oped in introduced salmonids. In regard to sal- Jara, and C. Gallardo. 1991 a. Ecological aspects
monid breeding in the lakes of southern Chile, of nematode parasites of introduced salmonids
the presence of parasites in introduced and au- from Valdivia River basin, Chile. Memorias do
Institute Oswaldo Cruz, Rio de Janeiro 86:115-
tochthonous fishes should be considered. This
122.
parasitological knowledge should precede initi-
, A. Contreras, V. Cubillos, W. Gesche, A. Mon-
ation of intensive salmon breeding activities in tefusco, C. Rebolledo, A. Mira, J. Arenas, J. C.
limnetic ecosystems in order to assess potential Miranda, S. Asenjo, and R. Schlatter. 1992. Par-
risk factors to fish populations. asitismo en peces, aves piscivoras y comunidades
humanas riberefias en los lagos Yelcho y Tagua-
Prevalence, mean intensity, and pathology by
Tagua, X Region de Chile. Archives de Medicina
Diphyllobothrium latum and Diphyllobothrium Veterinaria 24:77-92.
dendriticum have been reported in rainbow and , V. Cubillos, W. Gesche, C. Rebolledo, A. Mon-
brown trouts in lakes from southern Chile (Tor- tefusco, C. Miranda, J. Arenas, A. Mira, M. Nilo,
and C. Abello. 1991b. Difilobotriasis en sal-
res et al., 1991b). Infection by D. latum has been
monidos introducidos en lagos del sur de Chile:
reported in humans associated with consuming
Aspectos patologicos, relacion con infection hu-
raw and smoked salmonids in Chile (Torres et mana, animales domesticos y aves piscivoras. Ar-
al., 1989). chives de Medicina Veterinaria 23:165-183.
, R. Franjola, J. Perez, S. Auad, F. Uherek, J.
Acknowledgments C. Miranda, L. Flores, J. Riquelme, S. Salazar, C.
Hermosilla, and R. Rojo. 1989. Epidemiologia
Funding for this study was provided by grants de la difilobotriasis en la cuenca del rio Valdivia,
69/89 (FONDECYT) and S-92-01 (Direction de Chile. Revista de Saiide Publica 23:45-57.
Investigation, Universidad Austral de Chile. , W. Gesche, and O. Garrido. 1993. Primer
registro de Camallanus corderoi Torres, Teuber
y Miranda, 1990 (Nematoda: Camallanidae) en
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Copyright © 2011, The Helminthological Society of Washington