Veterinary parasites

Question 1

Dipylidium caninum

Answer 1

Lifecycle:
Eggs are ingested by flea larvae.
Fleas mature, containing infective cysticercoids.
Dogs or cats ingest infected fleas while grooming.
Adult worms develop in the intestine.
Clinical Signs:
Often asymptomatic.
May see anal irritation, weight loss in heavy infestations.
Diagnosis:
Presence of proglottids (segments) in feces or around the anus.
Eggs or proglottids visible upon microscopic examination of feces.
Treatment:
Praziquantel or other broad-spectrum anthelmintics.
Prevention:
Regular flea control is essential.

CESTODE

Question 2

Echinococcus granulosus

Answer 2

Lifecycle:
Dogs (definitive hosts) shed eggs in feces.
Intermediate hosts (sheep, cattle, humans) ingest eggs from the environment.
Larvae develop into hydatid cysts in organs.
Dogs ingest organs containing cysts, and adult worms develop in their intestines.
Clinical Signs:
Dogs often asymptomatic.
In intermediate hosts, symptoms depend on cyst location and size.
Diagnosis:
In dogs, difficult due to small size and intermittent shedding of segments. Serology or PCR for definitive diagnosis.
Imaging (ultrasound, MRI, CT) in intermediate hosts for cyst detection.
Treatment:
Praziquantel for dogs.
Surgical removal or PAIR (puncture, aspiration, injection, re-aspiration) for cysts in intermediate hosts.
Prevention:
Regular deworming of dogs, proper disposal of animal offals, and preventing dogs from feeding on carcasses.

Cestode

Question 3

Echinococcus multilocularis

Answer 3

Lifecycle:
Similar to E. granulosus but primary intermediate hosts are rodents.
Foxes, wolves, and domestic dogs/cats are definitive hosts.
Clinical Signs:
In definitive hosts, often asymptomatic.
Severe liver disease in humans due to larval cyst proliferation.
Diagnosis:
Coproscopic examination and coproantigen testing in definitive hosts.
Imaging and serology in humans.
Treatment:
Praziquantel for definitive hosts.
Long-term antiparasitic therapy (e.g., albendazole) for humans.
Prevention:
Regular deworming and preventing pets from hunting or eating wild rodents.

Cestode

Question 4

Taenia spp.

Answer 4

Lifecycle:
Eggs shed in feces of definitive hosts (dogs, cats).
Intermediate hosts (cattle, pigs, etc.) ingest vegetation contaminated with eggs.
Larval stages develop in tissues of intermediate hosts.
Definitive hosts ingest tissues containing larvae.
Clinical Signs:
Mostly asymptomatic in both definitive and intermediate hosts.
Possible intestinal blockage or irritation in heavy infestations in definitive hosts.
Diagnosis:
Detection of proglottids or eggs in feces of definitive hosts.
In intermediate hosts, detection of cysticerci in muscles or organs.
Treatment:
Praziquantel or other cestocidal drugs for definitive hosts.
No practical treatment for intermediate hosts; control is through meat inspection and prevention.
Prevention:
Preventing access to infected offal for definitive hosts.
Proper cooking of meat to kill cysticerci.

cestode

Question 5

Mesocestoides spp.

Answer 5

Lifecycle:
Indirect, involving a definitive host (carnivores) and two intermediate hosts (usually rodents and then possibly reptiles or birds).
Dogs and cats become infected by ingesting an infected second intermediate host.
Clinical Signs:
Often asymptomatic but may include diarrhea and weight loss in heavy infestations.
Diagnosis:
Observation of tapeworm segments in feces.
Microscopic examination of eggs in feces.
Treatment:
Praziquantel or fenbendazole.
Prevention:
Control of rodent populations.
Prevent pets from eating raw meat or scavenging.

Cestode

Question 6

Toxocara canis (Dog Roundworm)

Answer 6

Lifecycle:
Dogs or foxes shed eggs in feces.
Eggs become infectious after developing in the environment.
Ingestion by dogs or accidental ingestion by humans leads to infection.
Larvae migrate through organs and tissues, eventually settling in the intestines as adults.
Clinical Signs:
Puppies: Diarrhea, vomiting, pot-bellied appearance, poor growth.
Adults: Often asymptomatic.
Diagnosis:
Fecal flotation to detect eggs.
Clinical signs in heavily infested puppies.
Treatment:
Anthelmintics (e.g., pyrantel, fenbendazole, ivermectin).
Prevention:
Regular deworming of dogs, especially puppies.
Environmental sanitation to reduce fecal contamination

Nematodes

Question 7

Toxocara cati (Cat Roundworm)

Answer 7

Lifecycle:
Similar to Toxocara canis, but in cats.
Can be transmitted to kittens through mother’s milk.
Clinical Signs:
Kittens: Diarrhea, vomiting, poor growth, pot-bellied appearance.
Adults: Often asymptomatic.
Diagnosis:
Fecal flotation for egg detection.
Treatment:
Anthelmintics (e.g., pyrantel, fenbendazole).
Prevention:
Regular deworming, starting in kittenhood.
Environmental cleanliness.

Nematodes

Question 8

Ancylostoma caninum (Canine Hookworm)

Answer 8

Lifecycle:
Larvae in the environment penetrate the host skin or are ingested.
Larvae migrate to the intestines, becoming blood-feeding adults.
Clinical Signs:
Diarrhea, anemia, weight loss, and in severe cases, death.
Diagnosis:
Fecal flotation for eggs; anemia signs.
Treatment:
Anthelmintics (e.g., pyrantel, fenbendazole, ivermectin).
Prevention:
Environmental management to reduce larval contamination.
Regular deworming.

Nematodes

Question 9

Angiostrongylus vasorum (Canine Lungworm)

Answer 9

Lifecycle:
Dogs become infected by eating larvae within slugs and snails.
Larvae migrate to the heart and pulmonary arteries.
Clinical Signs:
Respiratory distress, coughing, exercise intolerance, coagulopathies.
Diagnosis:
Fecal Baermann technique for larvae.
Serological tests.
Treatment:
Anthelmintics (e.g., ivermectin, milbemycin oxime).
Prevention:
Prevent dogs from eating snails and slugs.
Regular use of preventive anthelmintics in endemic areas.

Nematodes

Question 10

Dirofilaria immitis (Heartworm)

Answer 10

Lifecycle:
Transmitted by mosquitoes.
Larvae migrate to the heart and pulmonary arteries, maturing into adults.
Clinical Signs:
In dogs: Cough, exercise intolerance, heart failure.
In cats: Often asymptomatic, sudden death.
Diagnosis:
Antigen and antibody tests for dogs.
Microfilariae detection in blood.
Treatment:
Dogs: Adulticide therapy, strict rest, supportive care.
Cats: No approved treatment, manage symptoms.
Prevention:
Monthly preventive medications.

Nematodes

Question 11

Strongyloides stercoralis (Threadworm)

Answer 11

Lifecycle:
Infection through skin contact with contaminated soil.
Larvae migrate to the intestines, becoming adults.
Clinical Signs:
Diarrhea, dermatitis at the infection site.
Diagnosis:
Fecal flotation, larval culture, or Baermann method.
Treatment:
Ivermectin or fenbendazole.
Prevention:
Hygienic management of kennel areas and bedding.

Nematodes

Question 12

Trichuris vulpis (Whipworm)

Answer 12

Lifecycle:
Dogs ingest eggs from the environment.
Eggs hatch in the intestines, where adults live.
Clinical Signs:
Diarrhea, weight loss, anemia (certain cases), dehydration.

Diagnosis:
Fecal flotation to detect characteristic whipworm eggs.
Treatment:
Anthelmintics such as fenbendazole, febantel, or milbemycin oxime, often requiring multiple doses.
Prevention:
Regular deworming with products effective against whipworms.
Environmental decontamination, although difficult due to egg resilience

Nematodes

Question 13

Praziquantel

Answer 13

Mechanism of Action: Increases permeability of parasite cell membranes to calcium, resulting in paralysis, dislodgment, and death of the parasite.
Used to Treat: Cestodes (tapeworms) in dogs, cats, horses, and livestock; also effective against some trematodes (flukes).

Question 14

Ivermectin

Answer 14

Mechanism of Action: Binds to glutamate-gated chloride ion channels in nerve and muscle cells of invertebrates, leading to increased permeability, paralysis, and death of the parasite.
Used to Treat: A broad range of parasites including nematodes (roundworms), ectoparasites (mites, lice), and the prevention of heartworm disease in dogs and cats.

Question 15

Fenbendazole

Answer 15

Mechanism of Action: Inhibits microtubule synthesis in parasites, disrupting essential structures and processes, leading to energy depletion and death.
Used to Treat: Gastrointestinal nematodes, lungworms, and some tapeworms in livestock, horses, dogs, and cats.

Question 16

Pyrethrins/Pyrethroids

Answer 16

Mechanism of Action: Act on the nervous system of insects, causing repeated nerve firing, paralysis, and death.
Used to Treat: Ectoparasites like fleas, ticks, and lice on animals.

Question 17

Milbemycin Oxime

Answer 17

Mechanism of Action: Opens glutamate-sensitive chloride channels in parasite nerve and muscle cells, causing paralysis and death. Also disrupts neurotransmission in heartworm larvae.
Used to Treat: Heartworm prevention, intestinal worms (hookworms, roundworms, and whipworms) in dogs and cats.

Question 18

Triclabendazole

Answer 18

Mechanism of Action: Causes tubulin dysfunction and inhibits the parasite’s ability to reproduce and absorb glucose, leading to energy depletion and death.
Used to Treat: Liver flukes (Fasciola hepatica and Fasciola gigantica) in cattle and sheep.

Question 19

Selamectin

Answer 19

Mechanism of Action: Activates invertebrate-specific chloride channels, leading to hyperpolarization of nerve cells, paralysis, and death of the parasite.
Used to Treat: Heartworm disease, fleas, ear mites, sarcoptic mange, and certain ticks in dogs and cats.

Question 20

Albendazole

Answer 20

Mechanism of Action: Inhibits microtubule synthesis, preventing glucose uptake and depleting energy reserves of the parasite.
Used to Treat: A broad spectrum of gastrointestinal parasites, lungworms, and liver flukes in livestock.

Question 21

Moxidectin

Answer 21

Mechanism of Action: Binds to glutamate-gated chloride channels, causing paralysis and death of the parasite. It has a longer half-life and better tissue penetration compared to ivermectin.
Used to Treat: Internal and external parasites including gastrointestinal worms, lungworms, and certain mites and lice in livestock, horses, dogs, and cats.

Question 22

Metronidazole

Answer 22

Mechanism of Action: Forms toxic radicals which damage DNA and other critical components within anaerobic bacteria and protozoa.
Used to Treat: Protozoal infections (e.g., Giardia) and anaerobic bacterial infections in dogs and cats.

Question 23

Equine Parasites

Answer 23

Cyathostomins (Small Strongyles)

Affected Species: Horses
Lifecycle: Eggs shed in feces → develop into larvae in pasture → ingested by horses → larvae burrow into intestinal wall → mature into adults.
Treatment: Ivermectin, moxidectin, and fenbendazole.
Strongylus vulgaris (Large Strongyles)

Affected Species: Horses
Lifecycle: Similar to Cyathostomins, but larvae can migrate extensively inside the host, causing more severe damage.
Treatment: Ivermectin, moxidectin.
Parascaris equorum (Roundworms)

Affected Species: Primarily foals and young horses
Lifecycle: Eggs shed in feces → develop into infectious larvae in environment → ingested → migrate through liver and lungs → return to intestines to mature.
Treatment: Ivermectin, pyrantel pamoate.
Oxyuris equi (Pinworms)

Affected Species: Horses
Lifecycle: Eggs laid around the anus → cause itching → eggs spread to environment → ingested by other horses.
Treatment: Pyrantel pamoate, ivermectin.
Anoplocephala spp. (Tapeworms)

Affected Species: Horses
Lifecycle: Eggs passed in feces → ingested by oribatid mites (intermediate host) → horses ingest infected mites while grazing.
Treatment: Praziquantel, often combined with other anthelmintics.
Gasterophilus spp. (Botflies)

Affected Species: Horses
Lifecycle: Eggs laid on horse hair → ingested by licking → larvae attach to stomach lining → passed in feces after maturation.
Treatment: Ivermectin, moxidectin.

Question 24

Cattle parasites

Answer 24

Ostertagia ostertagi (Brown Stomach Worm)

Affected Species: Cattle
Lifecycle: Eggs shed in feces → develop into larvae in pasture → ingested by cattle → burrow into stomach lining to mature.
Treatment: Ivermectin, fenbendazole, albendazole.
Fasciola hepatica (Liver Fluke)

Affected Species: Cattle, sheep
Lifecycle: Eggs shed in feces → hatch in water → infect snails (intermediate host) → larvae emerge and encyst on vegetation → ingested by livestock.
Treatment: Triclabendazole, oxyclozanide.
Dictyocaulus viviparus (Lungworm)

Affected Species: Cattle
Lifecycle: Eggs coughed up and swallowed → passed in feces → larvae develop in pasture → ingested by cattle → migrate to lungs to mature.
Treatment: Ivermectin, moxidectin.

Question 25

Sheep parasites

Answer 25

Teladorsagia circumcincta

Affected Species: Sheep
Lifecycle: Similar to Ostertagia ostertagi in cattle.
Treatment: Ivermectin, albendazole.
Haemonchus contortus (Barber’s Pole Worm)

Affected Species: Sheep
Lifecycle: Blood-feeding adult worms in the stomach → eggs passed in feces → larvae develop in pasture → ingested by sheep.
Treatment: Ivermectin, albendazole.
Nematodirus battus (Threadworm)

Affected Species: Sheep, particularly lambs
Lifecycle: Eggs survive winter in soil → hatch in spring → larvae ingested by grazing lambs.
Treatment: Benzimidazoles (e.g., albendazole), levamisole.

Question 26

Canine Parasites

Answer 26

oxocara canis (Canine Roundworm)

Affected Species: Dogs
Lifecycle: Eggs shed in feces → develop in the environment → ingested by dogs or transported by paratenic hosts → larvae migrate through tissues, some return to the intestine to mature.
Treatment: Pyrantel pamoate, fenbendazole, ivermectin.
Ancylostoma caninum (Canine Hookworm)

Affected Species: Dogs
Lifecycle: Eggs shed in feces → larvae develop in soil → penetrate skin or ingested → migrate to lungs, then to intestines to mature.
Treatment: Pyrantel pamoate, fenbendazole, ivermectin.
Dirofilaria immitis (Heartworm)

Affected Species: Dogs (primarily), cats
Lifecycle: Transmitted by mosquitoes → larvae migrate to heart and pulmonary arteries, mature into adults → adults produce microfilariae circulating in blood, taken up by mosquitoes.
Treatment: Adulticide treatment for dogs (melarsomine dihydrochloride), strict rest; no approved adulticide for cats, manage symptoms.
Ctenocephalides felis (Flea)

Affected Species: Dogs, cats
Lifecycle: Eggs laid on host → develop in environment → emerge as adults and re-infest animals.
Treatment: Topical or oral insecticides (e.g., fipronil, imidacloprid, nitenpyram).
Sarcoptes scabiei (Sarcoptic Mange Mite)

Affected Species: Dogs
Lifecycle: Burrow into skin to lay eggs → larvae emerge and mature on host.
Treatment: Ivermectin, selamectin, moxidectin.

Question 27

Feline Parasites

Answer 27

Toxocara cati (Feline Roundworm)

Affected Species: Cats
Lifecycle: Similar to Toxocara canis in dogs.
Treatment: Pyrantel pamoate, fenbendazole.
Ancylostoma tubaeforme (Feline Hookworm)

Affected Species: Cats
Lifecycle: Similar to Ancylostoma caninum in dogs.
Treatment: Pyrantel pamoate, selamectin.
Dipylidium caninum (Flea Tapeworm)

Affected Species: Cats (and dogs)
Lifecycle: Fleas ingest tapeworm eggs → cats ingest infected fleas while grooming.
Treatment: Praziquantel.
Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV)

Not parasites but significant infectious diseases in cats.
Transmission: FIV through bite wounds; FeLV through saliva, blood, and, to a lesser extent, urine and feces.
Management: No cure; focus on preventive care, avoiding exposure, and managing secondary infections.
Ctenocephalides felis (Flea)

Affected Species: Cats (and dogs)
Lifecycle: Similar to its lifecycle in dogs.
Treatment: Topical or oral insecticides (e.g., fipronil, imidacloprid).
Otodectes cynotis (Ear Mite)

Affected Species: Cats (and dogs)
Lifecycle: Live in the ear canal, feeding on epidermal debris and ear wax → direct transmission to other animals.
Treatment: Ivermectin, selamectin.

Question 28

Avian Parasites

Answer 28

Red Mite (Dermanyssus gallinae)
Affected Birds: Poultry, wild birds, and can affect cage birds.
Details: These mites feed on the blood of birds at night, causing irritation, restlessness, decreased egg production, and in severe cases, anemia. They hide in cracks and crevices during the day.
Treatment: Environmental treatment with acaricides, cleaning, and disinfection of housing. Insecticidal dusts or sprays applied to birds may also be recommended.
2. Northern Fowl Mite (Ornithonyssus sylviarum)
Affected Birds: Mainly poultry but can affect other birds.
Details: Similar to red mites, but they remain on the birds. Infestations can lead to feather damage, irritation, anemia, and reduced egg production.
Treatment: Treatments similar to red mites, focusing on both the birds and their environment.
3. Scaly Leg Mite (Knemidocoptes mutans)
Affected Birds: Chickens and other poultry.
Details: Burrow under the scales of the legs, causing thickening and deformity. The condition is painful and can lead to lameness.
Treatment: Application of petroleum jelly, paraffin oil, or specific acaricides under veterinary guidance to suffocate the mites. Environmental cleaning is also important.
4. Gapeworm (Syngamus trachea)
Affected Birds: Poultry, pheasants, and other wild birds.
Details: Parasites that live in the trachea, causing gasping for air, coughing, and in severe cases, suffocation.
Treatment: Anthelmintic treatments such as fenbendazole or ivermectin, administered under veterinary advice.
5. Coccidiosis
Affected Birds: Poultry and other birds.
Details: Caused by Eimeria species, affecting the intestines and sometimes other organs. Symptoms include diarrhea, blood in feces, lethargy, and reduced feed intake.
Treatment: Anticoccidial drugs like amprolium or toltrazuril. Management practices such as good hygiene and reducing overcrowding can help prevent outbreaks.
6. Lice and Feather Mites
Affected Birds: Chickens, cage birds, and wild birds.
Details: External parasites that feed on feathers, skin, or the blood of birds, causing irritation, feather damage, and in severe cases, anemia.
Treatment: Insecticidal sprays or powders specifically designed for avian use. Environmental cleanliness and regular health checks are key in prevention.
7. Trichomoniasis (Canker)
Affected Birds: Pigeons, raptors, and passerine birds.
Details: Caused by the protozoan Trichomonas gallinae, leading to lesions in the mouth, throat, and upper digestive tract. Can be fatal, especially in young birds.
Treatment: Antiprotozoal medications, such as metronidazole or carnidazole, under veterinary guidance.