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Deworming a dog: symptoms of worming and pills for dog deworming

Deworming the dog

Worms in a dog belong to internal parasites.

Please remember what the term actually means:

parasitism is a form of coexistence of organisms in which the parasite and its host participate.

The parasite is usually smaller in size and uses the host's organism as a living environment and food source.

Parasites can be internal (endoparasites), their place of existence is either inside the body or outside (ectoparasites), living on the outer covers of the body, usually on the skin and its products.

Parasites have a negative and pathogenic effect on the host's organism.

We distinguish between the final host, in which the parasite reaches sexual maturity and reproduces sexually, and the intermediate host, in which there are larval forms of the parasite, and in which the parasite can reproduce asexually.

There may be more than one intermediate host in the development cycles.

An intermediate host is not essential for all parasites, then the life cycle is simple, involving only one host.

In the simple cycle, sexual reproduction takes place in the host, and non-invasive forms (eggs, cysts, larvae) excreted into the environment transform into invasive forms.

Usually one intermediate host is involved in the composite cycle, sometimes there are more.

They are also present in some parasites paratenic hosts (reserve, accidental), they are not necessary to close the cycle, but they promote the spread of parasites in the environment.

The infestation of the host by parasites is referred to as the term invasion.

There are two different periods in the course of the invasion:

  • prepatent,
  • patent.

The pre-patent period, i.e. the latent period, is the time from the penetration of the parasite into the host until it reaches sexual maturity and begins to reproduce.

The patent period, i.e. the open period, is the time from the parasite reaching sexual maturity until the death of the parasite or host.

During this period, the parasites (eggs, larvae, cysts, oocysts, etc.) are excreted.).

There is no correlation between the occurrence of symptoms and the stage of infestation, and symptoms may appear soon after infection.

It is possible to re-infect the host with the parasite that already has individuals of this species.

This situation is called a super invasion.

The animal may also be re-infected after the previous parasites have been removed, this is the so-called. reinvention.

Infection most often occurs through the ingestion, but it is possible intrauterine, lactogenic (through milk while suckling the mother) or through the skin.

Parasites of importance for human and animal health in the temperate climate zone are of three types:

  • flat worms,
  • round worms,
  • arthropods.

In this article, dear reader, I will introduce you to the topic of flat and round worms, and ways of deworming a dog.

  • Worms in a dog
    • Fluke in a dog
    • A tapeworm in a dog
    • Nematodes in dogs
    • Ascaris in a dog
    • Hookworm in a dog
    • Whipworm in dogs
    • Wegorczyca in a dog
    • Angiostrongylosis in a dog
    • Heartworm disease in dogs
  • Deworming the dog
    • Deworming of the dog - nematodes
    • Dog deworming - heartworm Dirofilaria immitis
    • Deworming the dog - tapeworms
  • Diagram of deworming an adult dog
    • Risk group A
    • Risk group B
    • Risk group C
    • Risk group D

Worms in a dog

Flat worms (flatworms) are dorso-ventral flattened invertebrates, ranging in length from a few millimeters to over a dozen meters.

Among flat worms, only vortices are free-living animals, the rest are parasitic organisms.

In some flatworms, the body is segmented.

Parasitic forms have adhesive organs, such as suction cups, grooves or hooks, that allow them to attach to the host's tissues.

Flat worms include, among others flukes and tapeworms.

The flukes have a lanceolate, leaf-shaped or conical, unsegmented body in length from 0.2 to 130 mm.

The adherent organs are suckers.

Flukes, with one exception (family Schistosomatidae), are hermaphroditic.

Tapeworms have a flattened dorso-ventral body, segmented, divided into head, neck and strobe.

Mature forms are devoid of the gastrointestinal tract, they feed on the contents of the intestine by absorbing the food with the entire surface of the body.

Most tapeworms are bisexual (hermaphrodite) animals.

Roundworms (roundworms) are animals with elongated, oval, non-segmented, often threadlike bodies.

They are dioecious.

Most roundworms that parasitize humans and animals are nematodes.

Fluke in a dog

Parasitological examination

Alariosis in a dog

It is caused by the Alaria alata fluke, which can reach a length of 2-6 mm.

The dog as well as the fox and cat are its final hosts.

Development cycle

The first intermediate host is the Planorbis snail (coves), the second are tadpoles and frogs.

These flukes live in the small intestine of the final host.

Dogs become infected by eating them tadpoles and frogs.

Clinical symptoms

The invasion is usually not accompanied by any disease symptoms, this fluke is considered non-pathogenic.

Stool examination is useful for diagnosis, as the eggs of these parasites can appear in the stool.

Antiparasitic agents, for example, containing praziquantel.

Opistorchosis in a dog

The flukes of the Opistorchiidae family are flat, oval or spindle-shaped parasites in the bile and pancreatic ducts of mammals, birds and reptiles, as well as dogs.

Development cycle

Two intermediate hosts participate in the life cycle, freshwater snails of the genus Bithynia and fish, most often of the carp family.

Eggs excreted in the faeces of the dog or other final host, after getting into the water, are eaten by the snail, where the larva hatches out of the egg.

It leaves the snail's body and, while swimming in the water, looks for a second intermediate host.

The larva attacks the fish actively, getting through its skin to the muscles, where it transforms into metacercaria.

After being eaten by the final host, they are released in the digestive tract and travel to the bile ducts or the pancreas.

Period prepatent invasion is 3-4 weeks, whereas patent period lasts for years.


The presence of flukes in the bile ducts can lead to:

  • cyst formation,
  • epithelial hyperplasia,
  • inflammation of the walls of the ducts.

Clinical symptoms

Low-intensity invasions are usually asymptomatic, but an intense and longer-lasting invasion leads to:

  • emaciation,
  • gastric disorders,
  • anemia,
  • jaundice,
  • enlargement of the liver and its severe failure.

A stool test is helpful in the diagnosis.

Antiparasitic agents with praziquantel are recommended for treatment.

Prevention is about excluding raw or undercooked fish from the diet.

A tapeworm in a dog

Tapeworm dipylidium caninum | source: wikipedia

Tapeworms that infest dogs include:

  • belonging to the genus Dipilidiidae:
    • Dipylidium caninum,
  • to the genus Taenia:
    • Taenia hydatigena,
    • Taenia pisiformis,
    • Taenia ovis,
    • Taenia serrialis,
    • Taenia multiceps
  • belonging to the genus Echinococcus:
    • Echinococcus granulosus,
    • Echinococcus multiocularis.

Tapeworm infestation occurs by eating intermediate hosts or their organs containing larvae, for example by feeding dogs raw meat if slaughter waste.

In Poland, the occurrence of Dipylidium caninum is quite frequent, which results from its prevalence fleas and lice in environment.

Eggs shed by carnivorous animals die in the environment quite quickly, but under favorable conditions they can even overwinter.

Tapeworms live in the small intestines, attaching to the mucosa with clinging organs (suction cups, hooks).

Therefore, they cause mechanical damage to the intestinal mucosa, making it difficult to digest food and absorb nutrients.

Large tapeworms can even block the lumen of the intestine and lead to severe obstruction.

In addition, tapeworms eat away nutrients from the host, and their toxic metabolites can cause neurological disorders.

Tapeworms can even survive in the host for few years.

Among the clinical symptoms are disorders of the digestive system, such as diarrhea if constipation.

May be present emaciation or stunted growth in young animals.

It often comes to deterioration of the quality of the coat, the hair is puffed up and dull.

Occasionally there may be:

  • seizures,
  • stupor,
  • anxiety and excitement.

In the event of an invasion of Dipylidium caninum leaking from the anus may be the cause itching and perianal inflammation, then the dog can sledge, or rub the back of the body against the ground.

They are helpful in recognizing infestation with tapeworms faecal flotation and sedimentation tests, in which eggs and members of parasites are looked for.

It is also possible to see tapeworm members in the stool or on the hair around the anus.

Deworming preparations containing:

  • praziquantel,
  • epsiprantel,
  • nitroscanate.

Prevention consists in excluding raw meat, fish and slaughter waste from the diet, as well as regular use of anti-flea preparations.

It is important that humans can be an intermediate host for Echinococcus granulosus and Echinococcus multiocularis tapeworms.

Man can be an intermediate host for tapeworms

Tapeworms of the genus Dipilidiidae - Dipylidium caninum

Tapeworms of this species are dangerous parasites up to 80 cm in length.

They are equipped with four suction cups and a snout armed with hooks that hold in the small intestine where they live.

The pumpkin seed-shaped end members have the possibility of movement after detaching from the strobe.

They come out passively through the faeces or actively through the anus.

Apart from the host, they break up into bags containing packets of several to several dozen eggs, in which there are oncospheres equipped with 3 pairs of hooks.

Oncospheres are eaten by flea larvae or biting lice, which are intermediate hosts of the tapeworm.

The ultimate host is the dog, cat and fox, which become infected by eating fleas or biting lice.

The pre-patent period is two or three weeks, while patent about a year.

Clinical symptoms

In dogs, infestation is usually asymptomatic or symptoms are mild.

May be present anal itching associated with crawling limbs, which causes the dog to rub against the ground.

There may also be symptoms of the digestive system and disruption of its work that is manifested vomiting if diarrhea.

Over time it can come to deterioration of the hair quality or light emaciation.

It is helpful in recognition stool examination and visualizing tapeworm members on the hair coat.

Sometimes human Dipylidium caninum is accidentally infected, especially children.

After accidentally eating a flea or biting larvae, a person develops a tapeworm.

Possible symptoms of a tapeworm infestation in children include:

  • stomach pain,
  • sleep disturbance,
  • loss of appetite,
  • excessive mobility.

Tapeworm members are easy to find on underwear.

The basic action to protect humans against invasion is:

  • observe personal hygiene,
  • frequent hand washing,
  • fighting fleas in dogs and cats,
  • decontamination of the environment in which the flea-covered animals were kept.

It should be borne in mind that flea pupae in a cocoon can survive in cracks in the floor, carpets or carpets, even up to six months.

This developmental form of the flea is insensitive to parasiticides and is therefore the main cause of flea recurrence in dogs and cats.

That is why it is important to vacuum the rooms, pens and bedding of animals frequently, even daily.

Aerosol preparations containing dimeticon (Flee preparation) for use in rooms exposed to fleas.

It is very important to regularly use insecticides on animals, at intervals recommended by the manufacturer of the preparation.

These can be preparations in aerosol, spot pipettes - him or also flea pills.

Tapeworms of the genus Taenia

These include:

  • Taenia hydatigena,
  • Taenia pisiformis,
  • Taenia multiceps.

Infestation with Taenia genus rarely causes disease symptoms in dogs.

Increased invasion may be the cause gastric disorders and poorer quality hair.

Dogs become infected with tapeworms by eating tissues or internal organs of intermediate hosts that contain tapeworm larvae.

Intermediate hosts become infected by eating eggs excreted in the faeces.

Man can become infected with many species of tapeworms by swallowing invasive eggs.

In prevention, it is important to avoid dogs accessing intermediate hosts and not to feed them with raw meat and slaughter waste.

They are helpful in diagnosing an infestation stool tests.

In addition, the owner may notice tapeworms stuck to the hair.

Appropriate anthelmintic preparations are used in the treatment in a dose and intervals recommended by a veterinarian.

Taenia hydatigena

They achieve 1-5m length.

Skoleks is equipped with 4 suction cups and 2 rings of hooks.

The ultimate host is:

  • dog,
  • cat,
  • Nov.

Intermediate hosts are:

  • sheep,
  • cattle,
  • pigs.

Oncospheres from the gastrointestinal tract of intermediate hosts go with the blood to the liver where they settle, forming blackheads, i.e. blisters the size of a hen's egg filled with fluid, in which a large scolex on a thin neck is visible.

The final host becomes infected by eating internal organs along with blackheads.

The pre-patent period is 7-10 weeks, patent it 25 years.

Taenia pisiformis

Length tapeworms from 0.5 to 2 meters.

Skoleks also has suction cups and hooks.

The ultimate host is:

  • dog,
  • cat,
  • Nov.

Intermediate hosts:

  • rabbits,
  • hares,
  • rats,
  • mice.

In the intermediate host, after eating the tapeworm members filled with eggs, the larvae are released and migrate to the liver.

They settle as blackheads in the liver, mesentery, mesentery, and sometimes the pleura.

The final host becomes infected by eating the intermediate host or its organs with blackheads.

The pre-patent period for the invasion is 6-8 weeks, patent lasts approx 25 years.

Taenia multiceps

This tapeworm reaches up to a meter in length.

There are 2 rings of hooks on the scolex.

The ultimate host is:

  • dog,
  • cat,
  • Nov.

The intermediate host is mainly:

  • small ruminants (sheep, goats),
  • cattle,
  • wild ruminants,
  • sometimes a man.

When eaten by an intermediate host, the larvae travel through the bloodstream to the organs, eventually settling at the base of the brain, where they form a fluid-filled bladder containing up to several hundred scolexes.

The pre-patent period is 4-6 weeks, patent several years.

Taenia ovis

The ultimate host is the dog, the intermediate host is the sheep.

The larva in sheep settles in the skeletal muscles and the heart muscle.

Taenia serialis

The intermediate host is rabbits in which the larva settles in the subcutaneous tissue or in internal organs.

Occasionally, humans can also act as an intermediate host after ingesting eggs from contaminated dog faeces with water or food.

Tapeworms of the genus Echinococcus

Belong to them:

  • Echinococcus granulosus,
  • Echinococcus multiocularis.

Echinococcus granulosus

Very small tapeworms (2- 6 mm long) having 32 rings of hooks.

The dog is the ultimate host, the cat does not reach sexual maturity, and it is difficult for the fox to develop.

It lives in the small intestine.

Eggs released in the faeces are a source of infestation for intermediate hosts, including humans.

Eggs are invasive as soon as they are expelled along with the faeces.

The pre-patent period is 5-8 weeks, patent approx half a year.

Intermediate hosts are:

  • ruminants,
  • pigs,
  • horses,
  • man.

Infection occurs after eating eggs, for example, through dirty hands or contaminated water or food.

The tapeworm eggs, when eaten by an intermediate host, release the larvae, which are distributed with the blood throughout the body.

The larvae settle mainly in the liver and lungs and transform into single-chamber fluid-filled blisters.

As the blisters grow, they take up more and more space, causing the loss of organs that surround them.

In the human body, blisters are usually located in the liver.

Blisters in humans develop over many years and therefore become very large, putting pressure on adjacent organs.

The infection is asymptomatic for a long time.

In Poland echinococcosis it is a real threat, especially in rural areas. The echinococcus tapeworm is very dangerous to humans

Echinococcus multiocularis

Small tapeworms (1-3mm in length) with a strobe composed of only 3-4 members.

There are 2 rings of hooks on the scolex.

The final host is mainly a fox, but it is also sporadic in dogs and cats.

In a dog, it lives in the small intestine.

Carnivores become infected by eating intermediate hosts or their organs with blisters.

In the final host, the invasion is asymptomatic.

The pre-patent period for the invasion is 4-5 weeks, patent period approx half a year.

The intermediate hosts are small mammals - rodents:

  • vole,
  • bank vole,
  • muskrat,
  • grubber.

The expelled eggs are eaten by small mammals.

The larvae enter the liver with the blood, where they take the form of a cartilage-like structure with fluid-filled blisters and scolexes.

Larvae through the lymphatic vessels can metastasize to various organs.

A human can also become a nonspecific intermediate host in which the larvae settle in the liver.

The infection occurs after the consumption of water, food, soil contaminated with eggs, or through dirty hands.

This tapeworm causes a serious disease in humans, multi-chamber echinococcosis. If untreated, this disease has a mortality rate of over 90%.

Alveolar blisters in humans, they constantly grow and infiltrate the surrounding tissues like a malignant tumor, they can also metastasize.

The incubation period of disease in humans is long, even by 5-15 years, the invasion may be asymptomatic.

Treatment in humans alveolar echinococcosis it is very difficult and the disease can even lead to death.

The direct source of infestation for humans is often a dog or cat.

You should scrupulously follow the rules of hygiene and systematically deworm your cats and dogs.

It is also important to avoid feeding your animals raw or undercooked meat and offal.

Nematodes in dogs

The nematodes that parasitize dogs belong to several genera and species.

The nematodes are cylindrical or thread-like in shape and reach length from 1 mm to 1 m.

Nematodes can cause in dogs:

  • ascariasis,
  • hookworm,
  • the whipworm,
  • angiostrongylosis,
  • cutaneous and cardiac heartworm.

Ascaris in a dog

Ascaris canis toxocara canis | source: wikipedia

Roundworms they belong to the largest and most widespread group of parasitic nematodes in the digestive system of animals.

Dogs are the definitive hosts for Toxocara canis and Toxascaris leonina.

Toxocara canis are white worms or white-yellow nematodes.

The males are long 10 - 13 cm, females 12cm - 19cm.

The males Toxascaris leonina have a length 4 - 6 cm, females to 10 cm.

These roundworms live in the small intestine.

Female roundworms are characterized by high fertility, therefore there is an intense contamination of the environment with eggs excreted with the faeces.

Under favorable conditions, ascaris eggs can survive in the environment for many years, because they are surrounded by a thick shell.

Invasive roundworm eggs can be eaten by the final host (carnivores), but also by non-specific hosts (mammals, birds and invertebrates such as earthworms).

Encapsulated larvae in the tissues of nonspecific hosts they live for many years.

Ascaris life cycle

Toxocara canis eggs are excreted in the faeces.

Under the right conditions, they turn into invasive larvae.

Temperature less than minus 10 ° C and greater than 45 ° C cause the eggs to be killed.

The development of eggs in the environment to the invasive stage continues from 3 to 4 weeks.

Invasive roundworm eggs can be eaten by dogs and cats, but also by other animals: mammals, birds or invertebrates, they are random hosts (parathenic), in their tissues encysted larvae survive for many years.

In young dogs, after eating eggs with larvae or accidental hosts in whose tissues there are larvae, the larvae migrate through the intestinal blood vessels to the liver, heart and lungs.

From the lungs, the larvae travel to the bronchi and trachea from where, when swallowed, they re-enter the small intestine, where they settle and mature sexually.

The pre-patent period is approx 28-30 days.

In older dogs, after reaching the heart, the larvae are transported together with the blood to various organs (perirenal area, uterus, mammary gland, intermuscular tissue, liver, brain, etc.), where they encapsulate and remain viable for many years.

The larvae may leave the place where they are encapsulated during hormonal changes (pregnancy, heat) or weakened immunity.

Some of these larvae can re-enter the circulatory system, lungs, bronchi and trachea, and if swallowed, enter the intestines, sexually mature and reproduce.

In pregnant bitches, the larvae released under the influence of hormonal changes penetrate the liver of the fetus, and after the puppies are born, further migration and development of roundworms takes place.

Infection by this route is common, which results from the large accumulation of larvae in the body of the bitch and the possibility of successive release of larvae during subsequent pregnancies, even after a single infestation.

The released larvae also reach the mammary gland and, along with the milk, infect the puppies, this is lactogenic infection.

Infected puppies shed larvae in the faeces, which can also cause reinfestation of a bitch weakened by childbirth and lactation.

That is why it is so important regular deworming of puppies.

The development of Toxascaris leonina ascarids is different from that of the Toxocara genus.

The larvae hatched from the eaten eggs do not travel through the body, but live in the intestine, where they reach sexual maturity.

The pre-patent period is 7-10 weeks.

When a nonspecific host eats the eggs, the hatched larvae travel into the body cavity and accumulate in the tissues surrounding the abdominal cavity of the host.

Such random hosts, such as rodents or other small mammals, are also an important source of infection for dogs.


Toxocara spp. Larvae. they mechanically damage organs during their journey, while roundworms in the small intestine disrupt its motility and narrow the intestine's lumen.

The moving nematodes damage the intestinal epithelium and cause inflammation of the mucosa.

Parasite metabolites are toxic and allergenic.

Symptoms of ascariasis in a dog

Symptoms of ascariasis in a dog

The severity of clinical signs depends on the age of the animals, the intensity and the period of infestation.

Young animals are the most sensitive, in which the invasion of ascarids causes:

  • distorted or loss of appetite,
  • vomiting,
  • diarrhea with mucus or constipation.

In suckling puppies, T. canis induces strong stomach ache, which is the cause of the constant squeaking and whining.

It comes to:

  • emaciation,
  • stunted growth,
  • apathy,
  • anemia,
  • rickets.

The hair of the animals is dull, puffed up, thinning and without shine.

In puppies it is visible bloating and enlargement of the abdomen and increased intestinal peristalsis, especially after feeding.

Larvae of T. canis pass through the lungs during their migration, which can provoke inflammation of the airways with symptoms of cough, runny nose and shortness of breath.

A large number of parasites can cause bowel obstruction, and even perforation of the intestinal wall or obstruction of the bile ducts, which leads to death.

Immunodeficiency caused by invasion and secondary viral, bacterial or fungal infections are also causes of death.

The diagnosis of ascariasis is by looking for eggs in the feces.

The treatment uses anthelmintic preparations containing, inter alia:

  • pyrantel compounds,
  • oxybendazole,
  • flubendazole,
  • mebendazole,
  • febantel,
  • selamectin.

Prevention of ascariasis is difficult and requires strict compliance with the rules of hygiene.

Keeping the culture clean can greatly reduce the infestation of roundworms.

A person can become infected with the canine roundworm eggs, but it is an intermediate host, the parasite does not develop into a mature form.

Infection occurs through the ingestion of eggs.

The sources of eggs are:

  • contaminated soil,
  • water,
  • unwashed vegetables and fruits,
  • dirty hands.

In humans, the development of roundworms stops at the stage of the larvae that goes to the internal organs (visceral toxocarosis) or eyeball (ocular toxocarosis).

That is why it is so important to clean up dog droppings, which reduces environmental contamination with eggs. Cleaning up dog droppings reduces egg contamination of the environment

You should always follow the rules of personal hygiene, wash your hands before a meal, after playing with foreign animals, you should not feed children in playgrounds.

It is also important to deworm the animals regularly as recommended by your veterinarian.

Hookworm in a dog

Hookworm - Ancylostoma tubaeforme | source: wikipedia

This infection is caused by hookworms Ancylostoma caninum and Uncinaria stenocephala.

They are small nematodes in length from 5 to 21 mm, colonizing the small intestine.

Hookworms in the mouthpouch have cloves (Ancylostoma caninum) or cutters (Uncinaria stenocephala) that attach to the wall of the small intestine and collect blood.

In Poland, hookworms are common.

Development cycle

The life cycle is simple, with no intermediate hosts.

The eggs and the feces get into the soil, where, under favorable conditions, the larvae hatch.

These larvae, after moulting twice, become 3rd stage larvae, which they retain the ability to invade for several months.

The larvae, when eaten by a dog, undergo further development in the glands and lumen of the small intestine.

The parasites mature sexually and produce eggs which appear in your dog's feces from 14 to 17 days after infection.

Active invasion of the larvae through the skin is also possible.

The larvae then enter the lymph and blood vessels, and then along with the blood through the heart to the lungs, where, after piercing the alveolar walls, they penetrate the lumen of the bronchioles.

Then, through the bronchi, they travel to the trachea and larynx, and when swallowed, they go to the intestine, where they reach sexual maturity.

In this form of invasion, eggs are produced about a month after skin penetration.

Infection with Ancylostoma caninum is also possible intrauterine or by the lactogenic route along with mother's milk.

The pre-patent period therefore varies depending on the path of invasion and the type of parasite from 12 to 30 days.

Not all larvae mature, some penetrate the muscles or the intestinal wall and go dormant.

Dormant larvae are activated after some time and migrate to the small intestine (where they mature and reproduce sexually) or to the mammary gland from where they, along with the milk, infect puppies.


Hookworms they stick with their mouths to the mucosa, damaging it.

They are hematophages and feed on blood, after cutting the tissues with cutting elements in the mouth sac (teeth, cutting sticks).

Clinical symptoms

Low-intensity infections are usually asymptomatic.

In case of intense invasions hookworm may take the form:

  • over sharp,
  • spicy,
  • chronic,
  • secondary.

The acute form usually occurs in very young puppies as a result of an intrauterine infection.

Revealed severe anemia often leading to death.

Puppies from two weeks of age show serious symptoms:

  • they are apathetic,
  • mucous membranes have a pale shade,
  • feces are thin and watery, dark in color.

The prognosis is there unsuccessful, essential is Blood transfusion.

Also in the form of acute there is development severe anemia that could be the cause of death.

As chronic anemia may be absent or of a low degree, the secondary form is a development of the chronic form in poorly kept, debilitated animals, then severe anemia develops.

Identifying hookworms in a dog relies on stool examination, where parasite eggs are looked for.

The treatment uses antiparasitic agents such as:

  • pyrantel pamoate,
  • fenbendazole,
  • selamectin.

Healing can sometimes be difficult due to napping larvae that are not affected by routine anti-parasitic treatments.

After the adult hookworms are eradicated from the intestines, the dormant larvae are activated and travel to the gastrointestinal tract.

With a large number of dormant larvae, it is difficult to combat the infestation.

In prevention, it is important to follow the rules of hygiene and regularly examine the faeces or deworming animals, especially bitches intended for breeding.

In purebred dog kennels, routine disinfection of cages and runs and the use of concrete surfaces is recommended.

Whipworm in dogs

The cause of the invasion are nematodes Trichuris vulpis, common in Poland.

They have a thinner front part of the body, much longer than the back part.

The front part includes a throat.

Whipworms parasitize the large intestine of the host.

Development cycle

In eggs excreted in the faeces within approx 2 weeks an invasive larva develops.

The larvae found in the eggs can even survive in the external environment several years.

Dogs become infected by eating invasive eggs.

The larvae released in the intestine develop in the wall and then in the intestinal lumen.

The pre-patent period is quite long, it amounts to 11-15 weeks, while patent more than a year.


Whipworms stick with the thinner front part of the body into the intestinal mucosa, causing inflammation.

These nematodes feed on blood, causing anemia, and their secretions and excreta have a toxic effect on the host.

The larvae that damage the intestinal wall during development are also pathogenic.

Clinical symptoms

Intensive infestation is accompanied by bloody diarrhea and an admixture of mucus in the stool.

The animals are emaciated, anemic, and their growth is stunted.

Recognition is about stool examination, Characteristic lemon-shaped or barrel-shaped eggs with two rocking suppositories are sought.

The treatment uses antiparasitic drugs for several consecutive days, containing:

  • flubendazole,
  • fenbendazole,
  • mebendazole.

Prevention is difficult due to the high resistance of eggs to environmental conditions.

In farms or shelters, the top layer of soil should be removed or the ground should be hardened, for example concrete.

Wegorczyca in a dog

Strongyloides-stercoralis intestinal nematode | source: wikipedia

The cause of the invasion are the nematodes - Strongyloides stercoralis.

Only females parasitize.

They are very small nematodes that reach a length up to 2.2 mm.

The larvae found in the stool are of length up to 380 micrometers.

The invasion of nematodes in carnivorous animals takes place mainly in countries with a warm climate, in Europe it is reported sporadically.

The host is the dog, but also the cat, the fox and the human.

They are located in the small intestine.

Infection usually occurs through the skin, although it is also possible to eat the larvae.

It is also common to be infected with breast milk.

The life cycle is simple, with no intermediate host.

Females living in the intestines lay eggs, from which the larvae hatch in the digestive tract.

After getting into the environment with feces, they go through subsequent cycles until they become invasive larvae.

The larvae travel through the body via the bloodstream to the lungs and then through the trachea, larynx and throat to the intestine.

Some of the larvae migrate to deeper tissues, from where they are passed on to the offspring during lactation along with the milk.

The pre-patent period for the invasion is 9-19 days, patent 3-15 months.

In warm climates, generations of free-living nematodes are present, composed of males and females, alternating with parasitic females.

The larvae of free-living females are a parasitic form that is invasive to animals.


Mature nematodes damage the cells of the intestinal wall, while the larvae damage the skin and lungs during their journey.

Clinical symptoms

An intense invasion can manifest itself diarrhea with blood.

The penetration of the larvae through the skin causes its inflammation, itching and eruptions.

Migrating larvae contribute to development inflammatory changes in the lungs.

An intense and prolonged invasion leads to cachexia, and even death.


Diagnosis of worms in the dog

Apply stool examination, in which the nematode larvae are looked for.

Antiparasitic agents are used in the treatment.

Prevention of infestation is difficult due to the presence of larvae in the environment.

Nematodes circulate between different hosts, so it is worth remembering that Strongyloides stercoralis can also parasitize humans.

Angiostrongylosis in a dog

The cause of the invasion is the blood-red nematode Angiostrongylus vasorum in size 14 - 25 mm.

Single cases have been confirmed in Poland.

The ultimate hosts are dogs and foxes, and the intermediate hosts are land and water snails.

The development cycle of Angiostrongylus

First-stage larvae emerge from the eggs laid by nematodes in the lungs of the final host, which enter the larynx through the bronchi and trachea, and are excreted with the faeces when swallowed again and enters the gastrointestinal tract.

Stage I larvae in the intermediate host (snail) develop into invasive larvae.

After the dog eats the snail, the larvae travel to the pulmonary artery or heart where they settle and mature sexually.

It is also possible for the snail to be eaten by an incidental host such as a bird, rodent or amphibian.

The dog becomes infected by also eating an incidental host.

After snail dies, the larvae survive in water and on plants, posing a threat to the final hosts.

A dog can become infected even by drinking water from a contaminated tank or puddle.

The pre-patent period is 4 - 8 weeks, even patent 5 - 6 years.


Nematodes that settle in the pulmonary artery contribute to development pneumonia, larvae piercing the alveoli can induce hemorrhages.

Mature forms can get through the bloodstream to the eyeballs, central nervous system, liver, kidneys, muscles and other organs.

Clinical symptoms

Symptoms result from circulatory disorders, they are:

  • dyspnoea,
  • cough,
  • fainting.

In addition, it comes to:

  • weight loss,
  • anemia,
  • vomiting.

It is also possible sudden death of an animal.


It relies on searching for larvae in the stool, for example by the Baermann method.

It is possible to find the larvae in bronchial mucus.

Also available blood serological tests or detecting parasite antigens in the faeces.


There is a causal treatment aimed at eliminating parasites from the body and supporting and alleviating clinical symptoms.

In fighting parasites, the following are used:

  • moxidectin,
  • milbemycin,
  • fenbendazole.
Treatment must be carried out by a veterinarian as it may be life-threatening.

Killed worms reaching the blood vessels of the lungs can be life-threatening congestion.

That is why additional symptomatic treatment is so important.


Preventive measures to avoid dog contact with intermediate hosts are difficult to implement.

Prophylactic use of antiparasitic agents containing, for example, is possible milbemycin if moxidectin.

Heartworm disease in dogs

Microfilariae of dirofilaria immitis | source: wikipedia

The cause of the invasion is threadlike nematodes Dirofilaria immitis and Dirofilaria repens.

Adult specimens even achieve up to 30 cm in length.

Larvae - microfilariae, they have from 218 to 329 microns in length.

Dirofilaria development cycle

The disease is spread by mosquitoes that are spread by the larvae of the parasite - microfilariae.

Mosquitoes collect the larvae along with the blood, then in about 2 weeks the larvae reach the invasive stage.

During the mosquito blood collection, invasive larvae enter the wound and then enter the subcutaneous tissue and muscles, where they undergo the next stage of development.

They then migrate to their final settlement area where they mature sexually.

In the case of D. immitis is it heart and pulmonary artery (cardiopulmonary heartworm), for D. repens is it subcutaneous tissue (subcutaneous heartworm).

The subcutaneous form of heartworm disease is found more and more frequently in Poland.

A human can become an accidental and at the same time the final host.

The length of the development cycle depends on the ambient temperature, the prepatent period varies within limits 6-9 months, the patent period is even up to 5 years.

Clinical symptoms

Itching may be a symptom of heartworm disease

In the subcutaneous form of heartworm, these are diverse changes in the skin and subcutaneous tissue.

They result from both mechanical damage to tissues by parasites and the toxic influence of their metabolites.

Skin lesions may take the form of delimited nodules with parasites inside, or multifocal dermatitis accompanied by itching and erythema.

Massive microfilariae could be the cause multi-organ failure syndrome, covering the liver, kidneys and heart, ending the death of an animal.

In the cardiac form, Dirofilaria immitis parasitizes in right ventricle and pulmonary artery.

Parasites lead to a narrowing of the lumen of the pulmonary artery and disturb the functioning of the heart.

Blood clots form around the nematodes, which further disturb the circulation.

In addition, parasites cause inflammation of the vessels.

The symptoms are:

  • dyspnoea,
  • rapid fatigue of animals,
  • cough.

They can also join:

  • swelling,
  • ascites,
  • enlarged liver,
  • nephritis.


It puts on the base Blood tests (presence of microfilariae, PCR tests detecting the parasite antigen) or finding adults in subcutaneous tissue.

In the cardiac form, an X-ray of the chest should be taken.

Parasites can also often become visible during echocardiographic examination.

In the diagnosis of D. immitis, ELISA tests for detecting antibodies or antigens of the parasite are also available.


In the treatment of cutaneous heartworm disease, spot-on drops containing selamectin or moxidectin.

The preparation should be applied to the skin through 6 months on a monthly basis.

Surgical procedures are also implemented during which subcutaneous lesions are removed.

Treatment of the cardiac form includes, in addition to killing the adult parasites and their larvae, also supportive treatment to minimize the adverse effects of toxic drugs and to reduce the pulmonary complications that develop after killing the parasites.

In the first step, injectable drugs are administered to kill adults, according to a regimen tailored to the severity of the disease.

Then after approx 3-4 weeks drugs are administered orally to kill the larval forms of the parasite.

If, secondarily to cardiac heartworm has developed heart failure or eosinophilic inflammation lungs are treated appropriately.


In the prophylaxis of heartworm disease, spot-on preparations containing moxidectin and selamectin.

It can also be used orally milbemycin.

Keep in mind that heartworm disease is zoonotic.

You can learn more about heartworm disease in the article "Dog and cat heartworm disease "

Deworming the dog

Pills for worms in a dog

The deworming program is always individually adapted to the individual animal.

Factors that influence the frequency of treatment and the pills used to deworm your dog:

  • age of the dog: puppies and older animals are at increased risk compared to adults;
  • health condition: decreased immunity, fitness, external parasites present increase the risk of parasitic infestation;
  • reproductive status: pregnant and lactating bitches are a source of intrauterine and lactogenic infection in puppies;
  • environment, lifestyle and utility of the dog - dogs living in rural areas, in kennels and shelters, having contact with many other animals, hunting dogs are at increased risk;
  • traveling: traveling, especially to warm climates, increases exposure to certain groups of parasites;
  • diet used: feeding with raw meat and fish, post-slaughter waste, the possibility of eating rodents, snails increases the risk of infestation with internal parasites.

Deworming of the dog - nematodes

Deworming puppies

Puppies are dewormed from the second week of life, then every 14 days up to 2 weeks after weaning.

Subsequent treatments every 4 weeks until 6 months of age.

Deworming pregnant bitches

In order to prevent Toxocar transmission to puppies, pregnant bitches should receive the appropriate group preparation macrocyclic lactones in 40 and 55 days of pregnancy or fenbendazole daily from day 40 of pregnancy to day 14 postpartum.

Deworming a nursing bitch

They should be treated simultaneously with the first deworming of puppies.

Deworming dogs in an increased risk group

Dogs in an increased risk group (sports, competitions, exhibitions) should be groomed twice: maximum 4 weeks before and 2-4 weeks after the party.

Deworming dogs in kennels

Deworming is performed every 4 weeks or faecal examinations are performed at these intervals.

Deworming of working dogs

Working dogs (police dogs, rescue dogs, guide dogs) should be dewormed 12 times a year, to exclude the possibility of passing nematode eggs.

Deworming dogs in homes with young children or immunocompromised people

Dogs in homes with small children or people with reduced immunity should be dewormed 12 times a year, to exclude the possibility of passing nematode eggs.

Dog deworming - heartworm Dirofilaria immitis

Deworming your dog should be performed when traveling to areas endemic to heartworms.

Deworming should be performed no later than 30 days after the start of the trip, up to 30 days after returning, monthly intervals.

Deworming the dog - tapeworms

Dogs eating raw meat or offal not subjected to heat treatment (10 min temp. inside the meat 65ºC) or freezing (7 days at -17 to -20ºC) must be dewormed every 6 weeks against tapeworms.

In the case of finding fleas on the dog, one-time deworming combined with flea should be performed (fleas are a vector for Dipylidium caninum).

Journey to areas endemic to Echinococcus spp.

Dogs in high-risk conditions echinococcal tapeworms should be backed up 4 weeks after the start of the trip, then every 4 weeks, and a month after returning.

The stool test must be performed immediately after the trip, and treatment is performed when necessary.

Diagram of deworming an adult dog

For the sake of simplicity, the principles of deworming adult dogs can be divided into separate risk groups, depending on their lifestyle and behavior.

Risk group A

Dogs belonging to this group are under constant control on walks, do not run freely or run freely, remain under supervision, do not come into contact with foreign dogs, do not eat carcasses or faeces, do not hunt and eat prey and raw, uncooked meat.

Deworming: dogs in this group should be wormed against nematodes and tapeworms 1-2 times a year or alternatively should be performed at this time stool examination.

Risk group B

Dogs belonging to this group are under constant control during walks, do not run freely or run freely, remain under supervision, have contact with foreign dogs, do not eat carcasses or faeces, do not hunt and eat prey and raw, uncooked meat.

Deworming: dogs in this group should be dewormed against nematodes and tapeworms 4 times a year or alternatively, a stool examination should be performed during this time.

Risk group C

Dogs belonging to this group are under constant control during walks, do not run freely or run freely, remain under supervision, have contact with foreign dogs, do not eat carcasses or faeces, hunt and eat prey and raw, uncooked meat.

Deworming: dogs in this group should be wormed against nematodes 4 times a year and tapeworms 12 times a year or alternatively, a stool examination should be performed during this time.

Risk group D

Dogs belonging to this group run freely without supervision, have contact with foreign dogs, eat carrion or feces of other dogs, hunt and eat prey and raw, uncooked meat.

Deworming: dogs in this group should be wormed against nematodes and tapeworms 12 times a year or alternatively, a stool examination should be performed during this time.

If the group and risk of infection cannot be determined, the dog should be dewormed at least 4 times a year.

Current research indicates that Deworming a dog 1-3 times a year is not enough.


To deworm the dog or not?

Hope you already know why after reading this article deworming the dog is so important.

Due to the widespread presence of parasites in the environment and the still occurring cases of not cleaning up the faeces of your animals, infection can occur extremely easily.

If you have any questions related to the content, please post them under the article, I will reply as soon as possible.

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