Characteristics of the parasite and its life history
(1) Tapeworm canis
Mainly parasitic in the small intestine of dogs and cats, and occasionally in humans. Eggs are round, transparent, 35-50 mm in diameter, with two thin egg shells, containing six hook larvae. Intermediate hosts are canine, cat fleas and canine hair lice. Pregnant ovum tablets escape from the anus of dogs and cats or are excreted with feces.
After rupture, the eggs escape and are ingested by flea larvae, and the hexapod larvae hatch in their intestines and develop through migration. .
A single flea body can carry as many as 56 cysticercoids, which can be infected by dog tapeworms when dogs and cats eat fleas. It develops into an adult after about 3 weeks. Children are often infected by ingesting infected fleas and lice through close contact with dogs and cats.
The disease is widely distributed in all parts of the world, has no obvious seasonality, and has a very wide host range. The infection rate of dogs and cats is high, and wild animals such as foxes and wolves can also be infected;
The human body is mainly infected by children. Mild infection does not show symptoms, and severe infection in puppies can cause symptoms such as loss of appetite, indigestion, diarrhea or constipation, and anal itching.
Intestinal obstruction may also occur when the infection is particularly large. After the gestational period can be found in the feces of the dog, the characteristic oocysts can be observed under the microscope, which can confirm the diagnosis.
(2) Taenia vesicularis
parasitic in the small intestine of dogs and cats. The eggs are approximately elliptical, with a size of (38-39) mm X (0.3-0.35) mm, and use pigs, cattle, sheep, deer, etc. as intermediate hosts. The larvae are cysticercosis sclerosus, which often parasitize in the greater omentum, mesentery, liver, diaphragm, etc. of pigs, cattle, and sheep.
(3) Taenia bean tapeworm
The edges of the segments are serrated, so they are also called tapeworms. The eggs are round and 32-37 mm in diameter.
Taenia lumiformis parasites in the small intestine of dogs and occasionally in cats, and uses rodents such as rabbits and hares as intermediate hosts. The larvae are cysticercosis lentis, parasitic on the liver, omentum, mesentery, etc. of rabbits, and the number is usually several, dozens or even 200, in the shape of grapes.
(4) Tapeworms
There are three types of tapeworms that live in the small intestine of canines.
①Taenia polycephalus
The larvae are cerebral polycephalus. Multi-headed tapeworm, the worm body is 40-80 cm long and consists of 200-250 segments. The eggs are round, with a diameter of 20-37 microns. The larvae are parasitic in the brains of sheep, goats, cattle, yaks, camels and other animals. Sometimes they can also be found in the oblong brain or bone marrow, and people are also accidentally infected.
②Continuous multi-headed tapeworm
The body length of the worm is 20-75 cm, with 26-32 hooks on the apex, arranged in two rows. The larvae are continuous polycephaly, often parasitic on the subcutaneous, intermuscular, abdominal organs, myocardium, lungs, etc. of rodents such as hares, rabbits, and squirrels, forming cysts the size of a child’s fist, containing several head segments.
③Polytaenia stuartii
The body length of the worm is 20 cm, and there are 2 rows of small hooks on the apical process, a total of 32. Eggs are nearly round, 32-36 microns in diameter. The larvae are Polycephalus stennius, parasitic in the muscle, subcutaneous, thoracic cavity and esophagus of sheep, and occasionally in the heart and skeletal muscle.
(5) Echinococcus granulosus
The body consists of 1 head segment and 3 or 4 The segment consists of segments, not exceeding 7 mm. The cephalic segment is not large, with 28-50 hooks on the apical process, the egg size is (32-36) μm X (25-30) μm, and the outer layer has a thicker embryonic membrane with radial lines.
The larvae of Echinococcus granulosus are Echinococcus, which parasitize the liver, lung and other organs of various animals and humans, causing serious hydatid disease (hydatid disease),
The ultimate hosts are canine carnivores such as dogs, jackals, and wolves, parasitic in the small intestine, and the intermediate hosts are herbivores such as sheep, cattle, and camels, and humans.
It mainly harms its host in the form of larvae (echinococcosis), causing severe echinococcosis (hydatid disease). With the extension of the parasitic time, the hydatid grows continuously, and the largest can reach 30-40 cm.
Echinococcus can live in the human body for more than 40 years. The final host, such as dogs and wolves, devoured echinococcosis or the carcass of animals containing echinococcosis.
Echinococcus granulosus is more prevalent in areas with developed animal husbandry, and the main sources of echinococcosis infection in animals and humans are wild dogs and shepherd dogs; Sheep viscera containing echinococcosis, causing the transmission of Echinococcus between sheep and dogs.
(6) Midline tapeworm
The body length is 75-100 cm, and there are 4 on the head segment Well developed suction cups, without apex. The eggs are oblong in size (40-60) micrometers X (35-43) micrometers, and contain hexagonocysts in two membranes. The adult tapeworm midline is parasitic in the small intestine of dogs and cats, and the ground mites are the first intermediate hosts, which develop into cysticercoid-like in vivo; the second intermediate hosts are various rodents, birds and reptiles.
The tetrads and amphibians develop into tetrads after ingesting ground mites that resemble cysticercoids, and develop into adults in the small intestine after intermediate hosts or tetrads are ingested by the terminal hosts.
(7) Taenia mansoni
Mainly parasitic in the small intestine of cats and dogs. The worm body is about 100 cm long, the head segment is finger-shaped, the dorsal and ventral surfaces each have a longitudinal suction slot, the neck segment is slender, and the segment is generally wider than long. The eggs are nearly oval, slightly pointed at both ends, light gray-brown, with an egg cover at one end, and the egg shell is thin, containing many yolk cells and one embryo cell, with a size of (52-68) microns X (32-43) microns .
The development of Taenia mansoni requires two intermediate hosts. The first intermediate host is Daphnia daphnia, which develops into protocercariae;
The second intermediate host is Frogs, snakes, and birds, fish (and even humans as transport hosts) develop into spargans in their bodies. Cats, dogs, tigers, leopards and other carnivores are the final hosts, and the sparganes develop into adults in the small intestine.
The eggs are usually detected in the feces 3 weeks after infection. The lifespan of an adult worm in a cat is about three and a half years.
(8) C. broad-segmented bilobal trough tapeworm
The developmental history and man Similar to Taenia solani, it also needs to go through two intermediate hosts, the first intermediate host is Daphnia daphnia, and the second intermediate host is fish. Humans and carnivores such as dogs and cats are the ultimate hosts.
Final host ingests fish containing Sparganus and develops into adults 5-6 weeks after infection. Adult worms live 5-13 years in the human body. In endemic areas, human, dog, and cat feces contaminate water sources, which is an important reason for the infection of Daphnia daphnia. In addition, a variety of wild animals can also be infected, becoming the natural foci of the disease.
Clinical symptoms
When a large number of parasites are parasitized, the parasites damage the host’s mesentery with their hooks and suckers, often causing inflammation. The worms absorb nutrients and cause obstacles to the growth and development of the host; the toxins secreted by the worms can cause host poisoning; the worms aggregate into clusters, which can block the intestinal lumen of the small intestine, causing abdominal pain, volvulus and even intestinal rupture. When other mammals and humans serve as intermediate hosts, they mostly parasitize internal organs, causing serious diseases.
A mild infection in dogs is often asymptomatic. In severe infection, symptoms such as vomiting, chronic intestinal catarrhal, anorexia, heterophilia, progressive weight loss, malnutrition, and lack of energy in the sick dog; Symptoms of paralysis of the limbs. Canine tapeworm disease is often chronic.
Differential Diagnosis
(1) Canine Tapeworm and Canine Hookworm
Both have rough and dull coat
, loss of appetite, progressive weight loss, anemia, heterophobia, vomiting, diarrhea and other clinical symptoms.
Difference: The pathogen of canine hookworm disease is hookworm. The sick dog has bloody stools with mucus, or black tarry stools with a rancid smell; redness and itching between the toes, swelling and ulceration of the toes, or erosion of the corners of the mouth; colorless oval eggs can be seen in stool examination.
(2) Canine taeniasis and canine whipworm
Both have clinical symptoms such as diarrhea and weight loss.
Difference: The pathogen of canine whipworm is whipworm. There are bright red or brown blood in the feces of the sick dog, with a foul odor, and the fecal examination shows yellow-brown, thick and smooth eggs.
(3) Canine taeniasis and canine ascariasis
Both have reduced food intake, have heterophilia, vomiting, diarrhea, and sometimes have clinical symptoms such as excitement, convulsions, and epilepsy.
Difference: The pathogen of canine ascariasis is Toxocara canis. The sick dog sometimes vomits or excretes the parasite, and the feces are found to have parasite eggs (yellow-brown, with depressions on the surface of the round shell, such as honeycomb).
Tips
According to clinical symptoms, combined with the results of fecal examination of worm eggs. If it is found that the anus of the sick dog is often sandwiched with egg-pregnant segments that have not yet fallen to the ground, as well as short tapeworm segments in the feces, it can help to diagnose.
Prevention measures
(1) Prevention
①In order to ensure dogs and cats If they are healthy, they should be treated with internal deworming on a regular basis.
②Do not feed dogs and cats with waste from meat processing, especially abnormal meat and offal food that have not been harmlessly treated.
③The fish and shrimp caught in the endemic areas of schizophrenia should not be fed raw to dogs and cats.
④ Regularly kill intermediate hosts such as fleas and lice in the pet house and on the body surface.
(2) Treatment
①arecolic hydrobromide, 1-2 mg/kg for dogs Body weight, taken orally once.
②Chlorothiophene, 200 mg/kg body weight for dogs and cats, taken orally once, is effective for vesicular tapeworm disease.
③Butenamidine hydrochloride, 25-50 mg/kg body weight for dogs and cats, orally administered once. When expelling Echinococcus granulosus, take 50 mg/kg body weight once orally, and then take it once every 48 hours.
④ Praziquantel, 5 mg/kg body weight for dogs and 2 mg/kg body weight for cats, orally administered once.
⑤Albendazole, 10-20 mg/kg body weight for dogs, orally, once a day for 3-4 days.
