Nematodes: roundworms, pinworms, whipworms Flashcards

Question

Name some differences in the life cycles of Toxocara canis and cati.

Answer 1

Transplacental transmission is possible in dogs as well as lactogenic. Only lactogenic is possible for vertical transmission of T.cati in cats.

Answer 2

Definitive hosts: dogs, cats Paratenic hosts: rodents

Answer 3

Infectious stage: L2 larva in egg. Paratenic host infected with L3. Eggs develop outside fast! - 1 week (Toxocara species 4 weeks) No migratory phase - larva is in small intestine wall for two weeks, then moults Prepatent period: 10-11 weeks

Answer 4

Toxascaris leonina eggs Infectious stage: L2 larva in egg

Answer 5

Toxocara spp. Egg round, 75-90 µm, thick shell, surface golf ball-like Brown to black colour Content: single cell occupies almost all the shell

Answer 6

Toxascaris leonina Egg round, 70-85 µm Thick shell, smooth surface, „inner layer“ of shell braid-like Light coloured Content: single cell occupies only part of the shell

Answer 7

Young animals are more susceptible <3-6 months, especially newborns. In foals and yearlings - important cause of distress. Older animals are carriers of the parasite (encysted larvae). Infection gives immunity (partial or full). Disease names: ascariosis, toxocariosis, parascariosis, etc.

Answer 8

Prevalence Worldwide. More in tropical regions More in warm season In Estonia is prevalent Toxocara and Toxascaris often together

Answer 9

either ingestion of eggs with larvae inside or ingestion of paratenic hosts with infection (e.g. mice)

Answer 10

Mostly from migrating larvae. Eosinophilic infiltration. Liver Petechiae Destruction of tissues white spots (milk spots) - seen in recent infection - migration of larvae Larvae in lungs - Oedema - Emphysema - ascaris pneumonia Adults in intestines - mucoid enteritis, occlusion, perforation, peritonitis

Answer 11

Mostly asymptomatic or mild. Potbelly, retarded growth, irregular apetite vomiting and diarrhea (foul-smelling in horses). Heavy infections – migrating larvae - Stunted growth - Cough (pneumonia), nasal discharge, dyspnea - Pulmonary oedema – death Adults in the intestines - Enteritis, diarrhea (with phases of constipation), abdominal pain, perforation, peritonitis Toxascaris seems less pathogenic than Toxocara, infestation is usually without any clinical signs.

Answer 12

Visceral larva migrans (cutaneous larva migrans) - fever, lymphadenopathy, cough - Abdominal pain - Pruritic skin - Encephalitis – death Ocular larva migrans - Granulomas in retina - uveitis, chorioretinitis - loss of vision

Answer 13

Anamnesis and history Clinical signs Differential diagnosis: Other liver (milk spots), lungs, GI parasites Biliary colic

Answer 14

For intestinal stages: Benzimidazoles Avermectins For larval stages: Levamisole Ivermectin 3-4 days post treatment – clean pens

Answer 15

Deworm females 2 weeks after delivery. Deworm puppies at 2 weeks, and then every 2 weeks until weaning. Then, monthly until 6months. Deworm adult animals 4 x year.

Answer 16

Strict hygiene Frequent cleaning (3% formaldehyde, 2% cresol) Avoid RAW MEAT, paratenic hosts. No dogs on children's playgrounds. Anthelmintic treatment of young animals. Quarantine of newly purchased animals. Coproscopic screening

Answer 17

Oxyuris equi is a horse pinworm Family Oxyridae Order Oxyurida

Answer 18

Horses, donkeys Mostly in young animals (up to 1 year) & old horses.

Answer 19

Mucosal villi of the Caecum, colon, rectum

Answer 20

Mature Female: up to 15cm * Large greyish-white opaque worm * Body is transparent * Long narrow pin-like tail * Uterus opening|vulva situated anteriorly Mature Male: up to 1.2cm * Expanded caudal alae * Blunt tail * Single pin shaped spicule Double esophageal bulb in both sexes. L4 already has a developed mouth

Answer 21

Direct 1) Horse eats embryonated eggs with L3 – infection 2) Larvae hatches in the small intestine (A in image) 3) In the mucosa of the caecum or colon molts to L4 (3-11 days after infection) (B) 4) L4 moves to lumen of the caecum, small and large colon, molts again (7-8 weeks after infection) (C) 5) After fertilization, female migrates to the anus, extrudes her anterior end and lays eggs in clumps around perianal skin (up to 50 000 eggs per female) (C) 6) Fast development inside the egg – 3-5 days and 2 molts 7) Perianal skin starts to itch – horse scratch the skin and eggs rub off – environment is contaminated. Prepatent period 4-5 months Longevity of a female worm – 6months

Answer 22

Equine female adult pinworm (Oxyuris equi) laying a mass of eggs

Answer 23

Oxyuris equi causes: - Perineal dermatitis, tail itching - Colitis (L4) - But is mostly asymptomatic

Answer 24

Anamnesis Clinical signs + observation Laboratory diagnostics: Examination of faeces (adult worms) - Eggs found rarely - Stool sampled per rectum Examination of perianal clumps - Scotch-tape impression - native sample Necropsy

Answer 25

Other causes of dermatitis - Mange (acariosis) Other causes of itching - ectoparasites, insect bites, fungal diseases, drug side-effects, allergy, eosinophilic dermatitis, etc. Other causes of restlessness - Colics -GI parasites

Answer 26

Egg of Oxyuris equi / horse pinworm Egg: 85-95 x 40-45 µm, asymmetric, yellow to brown in colour, flattened along one side, and feature a mucoid plug at one end, U-shaped larva.

Answer 27

Oxyuris equi egg (horse pinworm) this egg is embryonated / larvae is developing or developed

Answer 28

Routine anthelmintic therapy - Ivermectin - Moxidectin - Benzimidazoles - Pyrantel - Recent reports show reduced efficacy of ivermectin and moxidectin – probable potential resistance. Accurate doses are important. Repeat scotch-test 2 weeks after treatment.

Answer 29

Routine deworming Stop re-infection cycle - Wash perianal region - Disinfect stables/pastures (walls, floor, posts, fence, water and feed bucket) - Change the bedding and feed regularly. In case of severe infection, don’t use pasture for 6 months.

Answer 30

Trichuris spp. which cause trichuriosis

Answer 31

Synonym: Trichocephalus spp. because „hair“ = „tricho“ is located on the head side and „cephalus“ means head (see image)

Answer 32

whipworms Anterior part is 2x (+) longer than posterior part. - Long and slender - whip-like - Place for the esophagus Posterior part - Thick and short - Place for the intestines and reproductive organs 3-8 cm long Males have spicule with sheath Their tail is coiled spirally

Answer 33

eggs of Trichuris spp. (whipworms) Size: 50-70 µm Form: lemon-shaped Shell: thick-shell, yellow to brown with 2 visible poles Content: granular PS: Due to size and shape, resemble eggs of the nematode Capillaria spp. (lower right in image). Trichuris egg poles are transparent.

Answer 34

Direct cycle: In feces, infective larvae develops inside eggs within 1-2 months (L1) – under optimal conditions. After ingestion, the egg dissolves in the duodenum and L1 stage larvae hatches. L1 penetrates the mucosal glands of the colon and caecum. Molts in the mucosa 4 times. Adult comes to lumen and lays eggs, their anterior part is attached to mucosa. Prepatent period 7-12 weeks Patency up to 16 months

Answer 35

Prevalent worldwide, common in Estonia Older dogs more intensively infected Infection heavier in younger animals Eggs are very resistant, last years in the bedding or ground.

Answer 36

caecum and colon Slender anterior part inside the mucosa

Answer 37

alimentary transmission with egg containing L1 stage larvae

Answer 38

Light infections are asymptomatic. Heavy infections: diarrhoea mucus and blood in faeces anaemia weight loss death Whipworms feed off blood. Infection in the mucosa of the colon, caecum. The anterior part of the worm inside the mucosa and posterior part on the mucosa.

Answer 39

Anamnesis Clinical signs quite unspecific Fecal analysis ❖ Usually low amount of eggs in the faeces ❖ Centrifugation-flotation method (at least 10 g faeces) ❖ Antigen test Necropsy

Answer 40

Anthelmintics - more effective against adults - less effective against larvae Probenzimidazoles, benzimidazoles, milbemycins Supportive treatment

Answer 41

Good hygiene – animal kennels, pastures Repeating the treatment 3 times – monthly intervals Reinfection is common Eggs survive for years

Answer 42

hairworms & threadworms

Answer 43

Parasite of birds and mammals. In the intestines, bladder, respiratory organs and liver. Causes Capillarioses

Answer 44

Whitish filamentous worm Male - 20mm and female - 30mm Has stichosome esophagus – 1/3 to 1/2 of the body length. - stichosome is a part of the esophagus - function: secretory gland Simple mouth Males have one simple spicule with a primitive bursa-like structure.

Answer 45

Aka lungworm though this term is usually used for other nematodes. Alt. bronchial capillariasis. a). Ingestion of infective eggs from the environment or via paratenic host (earthworm) b). Larvae hatch in the duodenum and migrate via the bloodstream to the lungs (through the liver and heart) c). In the lungs they settle in the bronchi, they molt 2 times and mature d). Following maturation of the worms; reproduction starts, eggs are laid, coughed up, swallowed and excreted via the feces. e). Prepatent period is about 6 weeks. In the environment, the infective larva develop in the egg in 5 – 6 weeks.

Answer 46

1. Dog ingests infective egg with L1 or the paratenic host. 2. In the duodenum the larva hatches and migrates to lungs through liver and heart. 3. From the lungs the larva migrates to nasal passages – develops to adult and lays eggs. 4. Eggs travel from mouth to intestines and out with feces.

Answer 47

1) Adult worms are located deep within the liver parenchyma of the host, and lay hundreds of eggs in the surrounding parenchymal tissue. 2) Eggs remain in the liver until the animal dies. 3) Or is eaten by a predator or scavenger. 4) Then unembryonated (not infectious) eggs pass through the digestive tract out in feces. 5) Eggs embryonate in the environment. 6) Embryonation is slow and may take between 6 weeks and 5 months. . 7) The cycle continues when embryonated eggs are eaten by a suitable mammalian. 8) Infective eggs hatch in the intestine, releasing L1 which penetrates the intestinal wall and migrate via the portal vein to the liver parenchyma within 3-4 days. Larvae take about 3-4 weeks to mature into adults and mate. Dogs, cats, humans are usually infected after ingesting embryonated eggs in fecally-contaminated food, water, or soil.

Answer 48

Light infection is asymptomatic Moderate to severe infection: C. aerophile: nasal discharge, sneezing, cough, dyspnoea, weakness, poor growth, death C. putorii: digestive disorders, vomiting C. plica: infection in the bladder, urinary disorders: painful and frequent, hematuria C. hepatica.: liver function disorders, icterus, apathy, anorexia, vomiting

Answer 49

Eggs Size: 60-80 µm and 30-40 µm Color: green to yellow brown Content: granular, unsegmented Shape: ovale, 2 polar plugs are transparent Shell: thick-shell

Answer 50

Based on clinical signs Faecal analysis with flotation method - eggs Nasal discharge - eggs in it Necropsy - scrapings from tissues and organs - native preparation - worms and eggs

Answer 51

Anthelmintic effective - benzimidazoles - ivermectin - levamisole Supportive treatment Good hygiene, avoid contact with earthworms

Answer 52

Capillaria, Angylostoma, Trichuris Capillaria eggs look similar to those of Trichuris species (large eggs and poles are non-transparent); C. eggs = both polar plugs are not protruding, so that the poles appear more or less rounded. PS: C. plica egg are found in the urine!

Nematodes: roundworms, pinworms, whipworms Flashcards

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