Canine Taeniasis

There are many types of tapeworms that parasitize in the small intestine of dogs. Not only the adult stage is very harmful to the health of dogs, but most of the larval stages use other domestic animals (or people) as intermediate hosts, seriously harming domestic animals. and human health.

Canine tapeworm pathogens and their life history

(1) Canine tapeworms (Diplopodium caninum, Tapeworm melon): The body of the worm is light red and 10 to 50 cm long. Mature body segments are 7 mm long, 2-3 mm wide, long oval in shape, and look like cucumber seeds. Each mature segment contains two sets of male and female reproductive organs, with the genital pore opening in the center of both sides of the segment. Fleas and hairlice are the intermediate hosts of dog tapeworms, in which they develop into cysticerci-like cysts. The final host becomes infected by ingesting a flea or tick containing a cystic tail, and develops into an adult worm in the small intestine in about 3 weeks.
(2) Midline tapeworm (midline tapeworm): The body length of the worm is 30 to 250 cm, and the widest part is 3 mm. The mature proglottids are nearly square, and each segment has a set of reproductive organs. The uterus is located in the center of the proglottids and is in the shape of a long vertical sac. Therefore, when viewed from the naked eye, there is a vertical line running through the center of the chain body of this tapeworm. It is known that midline tapeworms require two intermediate hosts. The first intermediate host is a coprophagous ground mite, in which cysticerci are formed. The second intermediate hosts are snakes, frogs, birds and rodents, in which four-grooved larvae are formed, which are mostly found in the abdominal cavity or liver, lungs and other organs of the second intermediate host. After being ingested by the definitive host, the tetrasulcus larvae transform into adults in 16 to 20 days.
(3) Taenia bullae (taenia marginale): The body length of the worm is 75 to 500 cm. The anterior segments are wide and short, and the posterior segments gradually lengthen. The mature segments are 10 to 14 mm in length and width ~5mm. The uterus has 5 to 10 pairs of large lateral branches, which are further divided into smaller branches. Each segment has a set of reproductive organs, and the genital pores open irregularly alternately on one side of the segment. The intermediate hosts are cattle, sheep, pigs and other domestic animals. The larvae are Cysticercus tenuitus, which parasitizes in the liver, omentum and mesentery of the intermediate host. Dogs are infected by swallowing the internal organs containing Cysticercus tenuitus. After 36 to 73 They develop into adult worms in the small intestine.
(4) Taenia taeniae (Seratotooth tapeworm), the body length is 60~200 cm, the genital pores are irregularly opened alternately on one side of the segments, slightly protruding, making the side edges of the body serrated, mature The length and width of the body segments are 10~15 mm x 4~7 mm: the uterus has 8~14 pairs of side branches. The intermediate hosts are rabbits and hares, and the larvae are cysticerci, which parasitize in the liver, omentum, mesentery, etc. of rabbits. Dogs ingest the internal organs containing leguminous cysticerci, which develop into adult worms in 35 to 46 days.
(5) Taenia multicephalus (Taenia polycephalum) has a body length of 40 to 100 cm and a width of 5 mm. The uterus has 9 to 26 pairs of side branches. The intermediate hosts are cattle and sheep, and the larvae are polycephalic larvae (cercariae), which parasitize in the brain of the intermediate host and sometimes in the medulla or spinal cord. Dogs become infected by ingesting brains containing multiple worms, which develop into adult worms in approximately 41 to 73 days.
(6) Echinococcus granulosus: The body of the tapeworm consists of 1 scolex and 3 to 4 segments, with a total length of no more than 7 mm. There is a set of reproductive organs in the mature proglottids, and the pregnancyThe length of the segments exceeds half of the total length of the insect, and the uterus is sac-shaped with no side branches and only some protrusions. The larvae of Echinococcus granulosus are Echinococcus, which parasitizes in the liver, lungs and other organs of a variety of animals and humans. Dogs become infected after eating organs containing Echinococcus.
(7) Mansoni tapeworm (Schizocephala mansoni): The tapeworm is about 100 cm long and 2~2.5 cm wide. The scolex is finger-shaped, with a longitudinal suction groove on the dorsal and ventral sides. The neck segment is slender. Proglottids are generally wider than long. The length and width of the proglottids are almost equal. There is a set of reproductive organs in the mature proglottids. There is a circular male genital pore in the center of the front part of the proglottids. The uterus is spirally coiled and located in the middle of the proglottids. The end opening of the uterus and the vaginal opening are located below the male genital pore respectively. The body of the insect is yellow-gray, and the center of the body segment is connected by gray-black dots due to the uterus and eggs. The tapeworm Mansoni requires two intermediate hosts: the first intermediate host is a freshwater copepod (such as Daphnia), in which protocercariae develop. The second intermediate hosts are frogs and snakes (fish, birds and even dogs can be used as transit hosts), in which sparganoides develop. Cats and dogs are the final hosts, and sparganoides develop into adult worms in their small intestines.

Key points for diagnosis of canine taeniasis

(1) Clinical symptoms: Except for the occasional discharge of mature proglottids in sick dogs, mild infection is usually unnoticeable. Severe infection may cause abnormal appetite (bulimia, heterophilia), vomiting, chronic enteritis, alternating diarrhea and constipation, anemia, weight loss, easy agitation or depression, and some may cause spasm or limb paralysis. When the worms form into clumps, they can block the intestines, leading to acute abdominal diseases such as intestinal obstruction, intussusception, volvulus, and intestinal rupture.
(2) Check for tapeworm proglottids: If it is found that there are gravid tapeworm segments hanging from the anus of the sick dog, and short tapeworm segments are mixed in the feces, it can help to diagnose the disease. The proglottids are white, the smallest ones are like grains of rice, and the ones in dogs can be about 9 mm long.

Measures for the prevention and control of canine taeniasis

(1) Therapeutic anthelmintic: use hydrobromoarecoline at a dosage of 1.5~2 mg/kg body weight, orally. Make the sick dog fast for 12 to 20 hours and then administer the drug. In order to prevent vomiting, dilute iodine tincture (10 ml of water, two drops of iodine tincture) should be given 15 to 20 minutes before taking the medicine. Or use praziquantel, the dosage is 5~10 mg/kg body weight per time, orally. Or use butenamidine hydrochloride, the dosage is 25~50 mg/kg body weight, once orally, to expel Echinococcus granulosus, use 50 mg, and then use it once every 48 hours.
(2) Preventive deworming: Preventive deworming should be carried out 4 times a year (once per quarter), and breeding dogs should be carried out 3 to 4 weeks before breeding. When deworming, the dog should be isolated within a certain range so that the excreted worms and feces can be collected and completely destroyed to prevent the spread of pathogens.
(3) Pay attention to cleanliness and eliminate sources of noise: properly dispose of slaughter waste to prevent dogs from eating intermediate hosts containing tapeworm larvae or their uncooked organs; keep the kennel and dog body clean, Frequently use insecticides to kill fleas and ticks on your dog and eliminate rodents.