Removal and quantif

Asian tapeworm from 

chub using Praziq

David Ward

Arizona Game and Fish Depa

Research Branch
Why ?
Asian Tapeworm
Asian Tapeworm

• Introduced with Grass Carp imported f• First discovered in the Little Colorado • Can cause high mortality in new host s• Destruction of the intestine - infected f

dying 20 days earlier and at nearly twiccontrols

R. Cole 2004 US

• listed as one of six potential threats hu
Year

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

Catch per hour and 95% CI

0.000.020.040.060.080.100.12

Asian Tapeworm 

Asian fish tapeworm
Co-evolved parasites an

• Co-evolved parasites generally do n

the persistence of their host species

• Individuals excluded from the best h

highly vulnerable to disease due to and the stress response - disease bproximal cause of death

• Non- co-evolved parasites and host
Mean = 

Choudhury et al. 2001

• No baseline information for adult hum

<150 mm TL
Can we quantify tapeworm 

fish using non-lethal me

• Anti-cestodal drug / Humans and • Has been used extensively in fish 

- No established protocols

PraziquantPrazipond 

Formula: C19 H21 N2 O2
Objectives

• Evaluate dosage and time neede

Asian Fish Tapeworm using Praz

• Evaluate effects and side effects 

Praziquantel use

• Establish a standardized protoco

fish

• Evaluate Asian fish tapeworm loa

humpback chub in the Little Colo
Methods
Methods

Control Expe

24

Praz
12 hours

• 4 different dosages of Pra

0.7 mg/l 1.5 mg/l 6.0 mg/l 36

• 2 time durations

Methods

24 hou

Total = 108 fish tested

Mean = 150 mm TL, Range 110 – 45
1⁄2 fish dissected immediately afte

1⁄2 fish dissected 1 month later
Dosage (mg/l) # of fish with 

12 hours 24 ho

0.71.56.036.0

4

5

2

0

53 1

0
Laboratory Conclus

• Praziquantel is safe for use on ch• Commonly used dosage < 0.7 mg

insufficient to remove 100 % of ta

• Minimum duration of treatment is • Minimum effective dosage is 1.5 

- Recommend 6 mg/l for 24 hr
Field trials 

• Evaluate tapeworm loads in ad

humpback chub

–Little Colorado River–Mainstem Colorado River

Effects of temperatureon tapeworm dynamics
0.68 grams

(25 ml) Isopropyl 

alcohol
259 m
2005 Asian Tapeworm in Hump

Total Length (mm)

0 50 100 150 200 250 300 

Number of tapeworms

05

101520253035

180185

2001 Anindo et al. found 

Fish <150 mm TL

Average = 18
2005 HBC

Total Length

0 50 100 150 200 250 300 350 400 450

Frequency

05

10152025

2004 HBC

Total Length

0 50 100 150 200 250 300 350 400 450

Frequency

05

10152025

160170180190

2005 Asian Tap

To

0 50 100 150 

Number of tapeworms

05

101520253035

180185
Could we Control Asian T

using Praziquantel 

• Entire river treatment and era

not likely

• Treatement of highly infected 

during monitoring activities - 

- Insert a few ml of liquid praz

down the throat with an eye 

- Needs laboratory evaluation
Conclusions

• Praziquantel can be used to mon

tapeworm loads in humpback ch

• Flooding may be correlated with 

loads

• Effects of cold mainstem temps - • Some level of control may be pos
Temperature Control De

• Baseline information on Asia

tapeworm prior to a TCD

• Methods in place to track cha

Asian tapeworm infestation
Acknowledgement

Andy MakinsterTeresa HuntScott RogersJoey SlaughterAnne KretschmannPam SponholtzRandy VanhaverbekeDewey Wesley

John RinneCodey CarterProject funded by Arizona Game and Fish - Sta