2.01 a - Blood and Tissue Nematodes Flashcards

Question

What is the migration of filiriae in the arthropod?

Answer 1

arthropod takes a blood meal; ingests microfiliriae microfiliriae shed sheaths, penetrate fly's midgut, and migrate to thoracic muscles migrate to head and arthropod's proboscis arthropod takes a blood meal and L3 larvae enter bite wound

Answer 2

Locate microfilariae in stained blood smear - Knott technique serology (lacks specificity)

Answer 3

Knott technique – used when filariasis is suspected, to concentrate the blood in order to increase the possibility of finding microfilariae.  2% formalin is added to 2ml of blood to lyse RBCs, fix blood protozoa, and kill and straighten microfilariae.  Centrifuge for 5 minutes at 1000 rpm.

Answer 4

Examine for the presence or absence of sheath (a thin, translucent eggshell remnant covering of the body of the microfilaria and extending past the head and tail.  Examine the tail area of microfilaria for the presence or absence of cells that exhibit characteristic array of stained nucleus.

Answer 5

- sheathed - body gently curved - tail is tapered to a point - the nuclear column is loosely packed and do not extend to the tip of the tail

Answer 6

- sheathed measuring approximately 170-230mm and have 2 terminal nucleai that are distinctly separated from other nuclei in the tail

Answer 7

- kinked and sheathed - nuclei crowded extending - tip of the tail tapers

Answer 8

- unsheathed, only about 150-350 um long - head is 2x longer than broad - no nuclei in tail tip

Answer 9

Elephantiasis, Bancroft’s filariasis

Answer 10

Malayan filariasis

Answer 11

Blinding filarial; river blindness

Answer 12

- In the early acute phase, fever and lymphangitis - After years of repeated exposure, chronic elephantiasis develops due to obstruction of lymphatics, lymph stasis and lymphadematous changes. - After death of the adult worm, a surrounding granulomatous thickening the lymphatic walls are formed causing obstruction and resultant enlargement below the blocked area. aka Bancroft's Filaria

Answer 13

- More often asymptomatic - In endemic areas, “filarial fevers” are seen with recurrent acute lymphangitis and adenolymphangitis - Topical eosinophilia (or Weingarten’s syndrome): resembles asthma with high eosinophilia and no microfilariae

Answer 14

(or Weingarten’s syndrome): resembles asthma with high eosinophilia and no microfilariae

Answer 15

- Localized subcutaneous edema (Calabar swellings), particularly around the eye - Caused by microfilariae migration and death in capillaries - Dying adults induce a granulomatous reaction - Proteinuria and endomyocardial fibrosis can also occur

Answer 16

- Fibrotic nodules on the skin encapsulate adults (Onchocercomas) - Progressively severe allergic onchodermatitis (pigmented rash) develops - Blindness occurs from the presence of microfilariae in all ocular structures - Very prevalent in Africa and on central American coffee plantations - Onchocerciasis is the major cause of blindness in Africa; insect control is difficult because Simulium spp breeds in running water.

Answer 17

- Diethycarbamazine | - Ivermectin

Answer 18

- Diethylcarbamazine

Answer 19

- Diethylcarbamazine (also prophylactically)

Answer 20

- Ivermectin

Answer 21

Trichnia worm

Answer 22

trichinella spiralis

Answer 23

Encysted Larvae

Answer 24

striated muscle tissue

Answer 25

trichinella spiralis larva encysted in the muscle cell Granuloma forms around the nurse cell and becomes calcified over time

Answer 26

Ingestion of raw/ undercooked contaminated meat

Answer 27

Diagnostic specimen: Skeletal muscle biopsy/ blood (LDH, Aldolase, CPK)

Answer 28

- Trichinellosis is acquired by ingesting meat containing cysts (encysted larvae) of Trichinella  - After exposure to gastric acid and pepsin, the larvae are released from the cysts and invade the small bowel mucosa where they develop into adult worms -  After one week, the females release larvae -  The larvae migrates to the striated muscles where they encyst - Encystment is completed in 4 to 5 weeks and the encysted larvae may remain viable for several years. - Ingestion of the encysted larvae perpetuates the cycle

Answer 29

-  Rats and rodents are primarily responsible for its endemicity  - Carnivorous/ omnivorous animals feed on infected rodents  - Humans are accidentally infected when eating improperly processed meat of these carnivorous animals.

Answer 30

intestinal phase migration phase muscular phase

Answer 31

shows small intestine edema and inflammation, nausea, vomiting, abdominal pain, diarrhea, headache and fever (1st week after infection)

Answer 32

shows high fever, blurred vision, edema of face and eyes, cough, pleural pains, and eosinophilia lasting 1 month in heavy infection (death can occur during this phase)

Answer 33

shows acute local inflammation with edema and pain Larvae encyst in skeletal muscles of limbs, diaphragm, and face

Answer 34

- Non life-threatening infection (self-limiting): rest, analgesics and antipyretics - Life-threatening infection: prednisone; thiabendazole (with caution due to side effects) - Cooking meat to 137F or freezing for 20 days at 5F will kill larvae

Answer 35

Dog roundworm

Answer 36

Toxocariasis

Answer 37

Puppies usually contract from the mother before birth or from her milk. At 3-4 weeks old, they begin to produce hundred thousands of eggs that contaminate the environment thru their feces.

Answer 38

Peripheral blood. Eosinophilia is the most important finding. Serologic testing (ELISA, immunoblot); serum total IgE markedly increased.

Answer 39

Eosinophilia is the most important finding.

Answer 40

- T. canis accomplishes its life cycle in dogs, with human as accidental hosts - Unembryonated eggs are shed in the feces dogs/puppies. Eggs embryonate and become infective in the environment. - Following ingestion by dogs, the infective eggs hatch and larvae penetrate the gut wall. - In younger dogs, adult worms develop and oviposit in small intestine. - In older dogs, larval encystment in tissues, reactivated in female dogs in late pregnancy and - Infect their puppies by the transplacental and transmammary routes. - T. canis can also be transmitted thru ingestion of paratenic hosts. - The life cycle is completed when dogs eat these hosts. - Humans are accidental hosts by ingesting infective eggs in contaminated soil.

Answer 41

T. canis accomplishes its life cycle in dogs, with human as accidental hosts

Answer 42

Unembryonated eggs are shed in the feces dogs/puppies. Eggs embryonate and become infective in the environment. Following ingestion by dogs, the infective eggs hatch and larvae penetrate the gut wall.

Answer 43

- In younger dogs, adult worms develop and oviposit in small intestine. - In older dogs, larval encystment in tissues, reactivated in female dogs in late pregnancy and - Infect their puppies by the transplacental and transmammary routes.

Answer 44

Humans are accidental hosts by ingesting infective eggs in | contaminated soil.

Answer 45

Covert toxocariasis Visceral larva migrans Ocular larva migrans

Answer 46

– mild, subclinical febrile illness in children. Symptoms include cough, difficulty sleeping, abdominal pain, headaches, behavioral problems.

Answer 47

– caused by migration of larva through the internal organs of humans. Symptoms: fatigue, anorexia, weight loss, pneumonia, fever, cough, bronchospasm, abdominal pain, headaches, rashes and occasionally, seizures.

Answer 48

– migration of larva into the posterior segment of the eye. Sympyoms: decreased vision, red eye, leokokoria (white appearance of pupil), unilateral visual loss, retinal fibrosis and retinal detachment can occur.

Answer 49

- In general, blood eosinophilia combined with a positive serologic test result indicates active toxocariasis and requires treatment. - Mebendazole or diethylcarbamazine kills the nematode larvae. - Prednisone can be used as an adjunct for patients with wheezing or other signs of inflammation.

Answer 50

- Dogs should be dewormed. Puppies should be dewormed at 2,4,6, and 8 weeks - Sandboxes should be covered when not in use. - Dogs feces should be disposed properly. - Wash hands before eating.

Answer 51

Angiostrongylus cantonensis

Answer 52

Most common cause of human eosinophilic meningitis.

Answer 53

- Final Host : Rat | - Intermediate Host : Snails & slugs

Answer 54

Diagnostic Exam : CSF examination with moderate to high WBC count; large numbers of Charcot-Leyden crystals in the meninges.

Answer 55

- Adult worms of A. cantonensis live in the pulmonary arteries of rats. - The females lay eggs that hatch, yielding first-stage larvae, in the terminal branches of the pulmonary arteries. - The first stage larvae migrate to the pharynx, are swallowed, and passed in the feces. - They penetrate or are ingested by an intermediate host (snail or slug). - After two molts, third-stage larvae are produced, which are infective to mammalian hosts. - When the mollusc is ingested by the definitive host, the 3rd stage larvae migrate to the brain where they develop into young adults.

Answer 56

After two molts, third-stage larvae are produced, which are infective to mammalian hosts.

Answer 57

Humans are indidental hosts of a. cantonensis

Answer 58

- Some infected people don't have any symptoms -- or have only mild symptoms that don't last very long. - Sometimes the infection causes a rare type of meningitis (eosinophilic meningitis). The symptoms can include headache, stiff neck, tingling or painful feelings in the skin, low-grade fever, nausea, and vomiting.

Answer 59

- There’s usually none since the parasite dies over time. Even people who develop eosinophilic meningitis usually don't need antibiotics. Sometimes the symptoms of the infection last for several weeks or months, while the body's immune system responds to the dying parasites. - The most common types of treatment are for the symptoms of the infection, such as pain medication for headache or medications to reduce the body’s reaction to the parasite, rather than for the infection itself. Patients with severe cases of meningitis may benefit from some other types of treatment.

Answer 60

- Don't eat raw or undercooked snails or slugs, frogs or shrimps, prawns - If you handle snails or slugs, wear gloves and wash your hands. - Always remember to thoroughly wash fresh produce. - When travelling in areas where the parasite is common, avoid eating uncooked vegetables.

Answer 61

- Toxocara canis = Ocular larva migrans – migration of larva into the posterior segment of the eye. Sympyoms: decreased vision, red eye, leokokoria (white appearance of pupil), unilateral visual loss, retinal fibrosis and retinal detachment can occur. Eye Worm (Loa Loa) - Localized subcutaneous edema (Calabar swellings), particularly around the eye - Caused by microfilariae migration and death in capillaries - Dying adults induce a granulomatous reaction - Proteinuria and endomyocardial fibrosis can also occur Blinding Filaria; River Blindness (Onchocerca volvulus) - Fibrotic nodules on the skin encapsulate adults (Onchocercomas) - Progressively severe allergic onchodermatitis (pigmented rash) develops - Blindness occurs from the presence of microfilariae in all ocular structures - Very prevalent in Africa and on central American coffee plantations - Onchocerciasis is the major cause of blindness in Africa; insect control is difficult because Simulium spp breeds in running water.

Answer 62

Wuchereria bancrofti Brugia malayi Loa loa (also prophylactically) Toxocara canis

2.01 a - Blood and Tissue Nematodes Flashcards

(87 cards)