Nematodes of Dogs, Cats, and Humans Flashcards

Question

Capillaria aerophila

Answer 1

Lundworm Capillaria aerophila Found in trachea, bronchi, and nasal passages of dogs, cats, and foxes. Is rare. Egg Double-plugged (operculated), resembling Trichuris, but is smaller; usually asymmetric Life Cycle Direct transmission by ingestion of infective L3 eggs  adults in trachea and lungs Clinical Signs Uncommon; may cause chronic, harsh cough

Answer 2

Lungworm Rare in U.S. - Found in trachea, bronchi and lung parenchyma in fibrous nodules up to 2 cm in diameter, usually around tracheal bifurcation Life Cycle L1 larvae passed in saliva or feces – is directly infective to others by ingestion of feces or lung tissue, or from an infected bitch grooming her puppies Diagnosis Larvae in sputum or feces Bronchoscopic examination for nodule formation at the bifurcation of the trachea ``` Clinical signs May cause tracheobronchitis, dyspnea, and coughing in young puppies Control Isolate and hand-rear pups Difficult to eradicate ```

Answer 3

Cat lungworm; several cases seen in Louisiana Site Lung parenchyma and small bronchioles Life cycle Indirect – Female lays eggs in lung tissue  L1 larvae (kinked tails) in trachea  swallowed and passed in feces  Ingested by mollusk  possible paratenic host  cat ingests mollusk or paratenic host  worms develop into adult in cat Clinical signs Rare; severe infections may cause respiratory difficulty and possible death

Answer 4

Bladder worm – usually no clinical signs Morphology 15 – 60 mm long Egg Bipolar; resembles C. aerophila egg Life Cycle Indirect – Earthworms are IH Diagnosis Bipolar eggs in urine sediment

Answer 5

Kidney worm; largest known nematode Final hosts Dogs, various wild animals (mink) in temperate, cold areas Site of infection Kidney parenchyma Morphology Red color; females up to 103 cm long; males up to 35 cm Egg Barrel shaped with operculae at both poles; mamillated

Answer 6

Eggs to water environment in FH urine  annelid (Lumbriculus variegatus)  2 molts  FH infected by ingestion of annelid or paratenic host  L3 migrates to liver  kidney (right kidney more commonly infected because of location adjacent to liver) Pathology Eventually occupies entire kidney, leaving only a sac (renal capsule); 2 – 3 worms/ kidney; infection is not patent (producing eggs) unless both sexes are present in same kidney

Answer 7

Esophageal Worm Final hosts Dogs, wild canids, wild felids Morphology Females up to 80 mm; males up to 54 mm long; coiled and reddish in color when fresh Egg Small, thick-shelled; embryonated; parallel sides – “paper clip” egg

Answer 8

Live in large (up to golf ball size) fibrous nodules in wall of esophagus and stomach (up to 40 worms/nodule)  small fistulae to lumen of gut  eggs pass through fistulae  out in feces  ingested by IH (beetles)  develop to L3  FH infected by ingestion of IH or paratenic host  L3 released in FH stomach  circulation  aorta, where remain about 3 months  then pass through wall to adjacent esophagus  form nodules

Answer 9

pathology Malignant esophageal sarcomas – very close association Hypertrophic pulmonary osteoarthropathy – incomplete association – thickening of the bones of the extremities Diagnosis Eggs on fecal exam – shed intermittently Radiograph after barium swallow Endoscopy

Answer 10

Stomach worms Morphology Similar in size to ascarids; C-shaped Egg Small, thick-shelled, embryonated Life cycle Indirect – IH beetles, cockroaches, crickets, etc. Pathology Attaches to stomach wall; causes ulceration, gastritis, some blood loss Diagnosis Eggs in feces

Answer 11

Pinworm of humans Morphology Males 2-5 mm long; females 8-13 mm long, light yellowish-white, thin sharply pointed tail Site of infection Cecum (appendix) and surrounding small and large intestine; female migrates to anus to lay her eggs

Answer 12

Reinfection by contamination of hands  ingestion of infective eggs Contaminated clothing, bedding, etc. Airborne – eggs survive several days in dry dust; several weeks in high humidity and moderate temperatures Retroinfection thought possible (eggs hatch and larvae migrate back into rectum)

Answer 13

``` Symptoms None in the majority of those affected Anal pruritus Young girls  may invade vagina  local irritation May interfere with sleep ``` Treatment Anthelmintics, such as pyrantel pamoate Strict sanitation

Answer 14

Filarial Worms Morphology Like heartworms, but smaller (up to 10 cm long) Site of infection Major lymphatic ducts, coiled in nodular masses – in afferent lymphatic vessels Life cycle Similar to heartworms – prepatent period 6-12 mo.

Answer 15

Diagnosis Microfilariae (L1) in blood Some cases occult Treatment Avermectins Prevention Preventing mosquito bites

Answer 16

Africa/South America Similar to W. bancrofti IH – Blackfly ``` Pathology Onchocercomas Dermatitis/depigmentation Sclerosing keratitis  blindness Dwarfism ``` Diagnosis Microfilariae in skin snips