Mahatma Jyotiba Fule College of VeterinaryScience and Animal Husbandry, Chomu (Raj.)

PRESENTED BY:Dr. Vikram Punia

2020-2021Assistant professor

DEPARTMENT OF VETERINARY PARASITOLOGY

COLLEGE OF VETERINARY SCIENCE & ANIMAL HUSBANDRY, CHOMU (RAJ.)

HYMENOLEPIDIDAE , TAPEWORMS OF DOG

•

•

•

•

•

•

•

•

•

•

Family :Hymenolepididae Cestodes are usually narrow and thread- like in appearance.

Tape worm are small to medium in size with retractable bearing

a single circle of hooks.

Rostellum bears 8-10 hooks.

Suckers are unarmed .

Single set reproductive organs in each proglottid.

Ovary is median in position, lobed and transversely elongate.

Testes are up to 4 in number and arranged in a row or a triangle.

Vitelline glands are potato- shaped.

Uterus is sac- like.

Cirrus is spinosed.

Hymenolepis nanaCommon name : Dwarf tape worm

Host : Rodents, primate and man.

Lifecycle : Direct or indirect with flour beetles or

fleas.

Adult size : 25-40 mm.

Common cestode of man in the tropics and

subtropics.

•

•

Eggs

Eggs are oval or sub-spehrical and smaller, ranging

40-60 um x 30-50 um. On the inner membrane are two

poles, from which 4 to 8 polar filaments spread out

between the two membranes.

The oncosphere has six hooks. Notice in picture the

extra detail of the two polar thickenings on the

membrane of the oncosphere with filaments extending

into the space around the hexacanth embryo.

Egg of Hymenolepis nana

Lifecycle

Lifecycle is direct and cysticercoids develop within the villi of

small intestine.

Self – infection through ingestion of eggs containing the

developing cysticercoids discharged with own faeces. Auto-

infection where the cysticercoids while in intestine hatch out from

the eggs and attach to mucosa to grow into adult worm.

Pre-patent period 16 days.

Pathogenesis

occur only with heavy infections and are most apparent in

children.

Gastrointestinal discomfort

Diarrhea

Weakness

Poor appetite/anorexia

Headaches

Complications: discomfort and dehydration from prolonged

diarrhea 

Diagnostic Tests:

Examination of the stool for eggs and parasites confirms the

diagnosis. Concentration techniques and repeated examinations

will increase the likelihood of detecting light infections. See

Morphology.

 Treatment

Praziquatel as a single dose is currently the treatment of choice.

Expect a full recovery following treatment. Both Niclosamide and

praziquantel have been very effective and had minimal side

effects. Niclosamide causes death to the tapeworm by interfering

with oxidative phosphorylation, use 40 mg/kg for one dose only in

children. Praziquantel causes paralysis and death use 25 mg/kg

for one dose only

•

•

•

•

•

•

The tapeworms of dog are as follows:

Dipylidium caninum

Taenia hydatigena

Taenia multiceps

Echinococcus granulosus

Mesocestoides lineatus

Diphyllobothrium latum

Dipylidium caninum

Common name :Double pored dog tapeworm.

It also occurs in man and cat.

Location : Small intestine

I/H : Dog flea: (Ctenocephalides canis), Dog lice:

 Trichodectes canis and Heterodoxus spiniger)

Metacestode stage : Cysticercoid

•

•

•

•

•

Morphology

Retractable rostellum armed with three or four rows

of rose thorn shaped hooks.

Each segment contains two sets of genital organ.

Vitelline glands and ovary form a mass on either side

resembling a bunch of grapes.

In the gravid segment uterus are replaced by egg

capsule or egg packets.

Egg packets contain 30 eggs per packet. Gravid

segments are elongate and oval in shape

resembling cucumber seed shape.

Rose thorn shaped hooks.

Dipylidium caninum

 D. caninum egg packet, containing 8 visible eggs

D. caninum eggs are round to oval (average size 35 to 40 µm;

range 31 to 50 µm by 27 to 48 µm) and contain an oncosphere

that has 6 hooklets. Proglottids of D. caninum contain

characteristic egg packets that are round to ovoid and contain 5

to 15 or more eggs each.

•

•

•

•

LIFE CYCLE

The gravid segments are passed in the faeces or spontaneously

leaving the host and crawling on the body surface of the host or

on the floor, during this process eggs are released.

Egg are ingested by larval stage of fleas, but cysticercoid

development occurs in the adult flea.

D/H acquires infection by ingestion of infected adult flea.

Man acquires infection by accidental ingestion of flea while

playing with dog and cat.

Egg ----> Larval flea ----> Adult flea ---->D/H

•

•

PATHOGENESIS

It depends upon the age of host. Adult worms are not

pathogenic to dog but heavy infection causes abdominal

pain, un-thriftiness, diarrhea or constipation and rarely

intestinal obstruction may occur.

When gravid segment leave the intestines they cause

severe irritation around the perianal area and due to

constant irritation the dog will dragging of the anus over

the ground. This condition is known as “anal pruritus”.

•

•

•

•

•

•

•

Diagnosis

Demonstration of egg packets in faeces.

Macroscopic examination of feaces for gravid segment.

Treatment

Arecoline hydrobromide - 1 to 2 mg/Kg b wt.

Praziquantel – 5 mg/Kg b wt.

Niclosamide – 100 to 150 mg/Kg b wt.

Mebendazole – 100 to 200 mg/Kg b wt. Twice daily fo 5

days.

Bithionol – 200 mg/Kg b wt.