Helminth Diseases (Exam 2)

Question 1

three classes of parasites that cause disease in humans

Answer 1

protozoa, helminths, ectoparasites

Question 2

transmission of helminth diseases

Answer 2

• food and water, vectors, direct contact
• prevalent in tropical countries
• developing countries => 90% have at least one worm
• presence in U.S. is of increasing concern because of immigration, travel, HIV (physicians here are unable to recognize helminth diseases)

Question 3

classification of Helminths

Answer 3

• flat worms (Digenian flukes)
• tapeworms (cestodes)
• round worms (nematodes)

Question 4

types of fluke diseases

Answer 4

• schistosomiasis (bilharzia)
• opisthorchis sinensis (chinese liver fluke)
• paragonimus sp. (lung fluke)
• echinostome (human fluke)

Question 5

what is the 2nd nastiest parasitic infection?

Answer 5

schistomiasis

Question 6

schistosomiasis (symptoms)

Answer 6

• itchiness; damage to liver, intestine, bladder
• rarely, eggs move to brain and spinal cord => seizures and paralysis
• coughing up blood (oesophagogastic)

Question 7

What helminth disease is called ‘Katayama’ fever?

Answer 7

Acute schistosomiasis

Question 8

What sickness does acute schistosomiasis represent? What are the symptoms and how long do they last?

Answer 8

Resembles ‘serum sickness’ (immune disease)

Symptoms: often asymptomatic or flu-like; last weeks to months

Question 9

What happens with chronic intestinal schistosomiasis?

Answer 9

eggs get trapped in liver –> fibrosis
affects intestines (severe)
symptoms seen years after infection
granulomatous inflammation around eggs

Question 10

chronic hepatosplenic schistosomiasis

how to diagnose?

Answer 10

similar to chronic intestinal schistosomiasis

diagnosis: biopsy of liver to see cellular granulomas that occur at block blood flow

Question 11

what disease normally infects birds or small mammals and is not capable of fully developing in man?

Answer 11

swimmer’s itch (cercarial dermatitis)

Question 12

how is schistosomiasis diagnosed?

Answer 12

• finding eggs in urine or stool; must be tested on multiple days
• serum testing for antibodies -> must wait 6-8 week post infection

Question 13

what is the third most prevalent worm parasite in the world and endemic in Asia?

Answer 13

Opisthorchis Sinensis

Question 14

what type of helminth is opisthorchis sinensis?

Answer 14

flat worm (chinese liver fluke)

Question 15

what helminth is capable of causing cancer?

Answer 15

opisthorchis sinensis

Question 16

how is opisthorchis sinensis diagnosed?

Answer 16

identification of eggs in stool specimen with microscope

Question 17

what is the portal of entry and exit for opisthorchis sinensis?

Answer 17

entry: ingest raw or undercooked fish
exit: feces

Question 18

what helminth feeds on bile?

Answer 18

opisthorchis sinensis (chinese liver fluke)

Question 19

which helminth disease has an intermediate host of >54 species of freshwater snails?

Answer 19

Paragonimus (infectious lung fluke endemic in Asia)

Question 20

Which helminth disease has an intermediate host of 1 species of freshwater snail?

Answer 20

schistosomiasis

Question 21

what are the symptoms for long-term infections of paragonimus?

Answer 21

mimics bronchitis or TB

Question 22

How is Taeniasis transmitted?

Answer 22

humans pass tapeworm segments/eggs in feces and contaminate soil -> cows and pigs infected when eating -> humans become infected from eating beef or pork

Rare in U.S. unless there is poor sanitation

Question 23

what disease can Taenia eggs cause in animals and how?

Answer 23

eggs in animal’s intestine hatch and migrate to striated muscle, causing cysticercosis

Question 24

what helminth disease causes gradual weight loss that is not noticeable?

Answer 24

Taeniasis

Question 25

what are the tapeworm species that cause Taeniasis? which causes the most symptoms and why?

Answer 25

beef, pork (T. solium), asian (T. asiatica) beef (T. saginata) causes the most symptoms because it is larger in size (up to 10 m; the other two tapeworms are about 3 m)

Question 26

which helminth disease has the visible sign of segments of worm in feces?

Answer 26

taeniasis

Question 27

what causes cysticercosis? what parts of the body are infected and what is the result?

Answer 27

Cysticercosis is caused by larval cysts of T. soleum (pork tapeworm). The cysts infect the brain, muscle, tissue and cause seizures

Question 28

what contains testes and uterus?

Answer 28

tapeworms

Question 29

what is the largest parasite that infects humans?

Answer 29

fish tapeworm (Diphyllobothrium latum)

Question 30

what is the portal of entry and exit for fish tapeworm?

Answer 30

entry: eating raw or undercooked fish that contain cysts exit: stool (larvae grown in 3-6 weeks up to 30 feet)

Question 31

what are the roundworms?

Answer 31

- Enterobius (pinworms) - Ascaris Lumbricoides - Trichinellosis - Trichuris Trichuria (tapeworms) and hookworms - lympathic filariasis (Elephatiasis) - onchocera volvulus (river blindness) - dracanculus medinensis (guinea worm)

Question 32

what roundworm lays eggs at night time that causes intense itching and nightmares?

Answer 32

pinworms Very infectious!

Question 33

what is the most common helminthic disease in the U.S.?

Answer 33

Enterobius vermicularis (pinworm disease)

Question 34

how is enterobiasis transmitted?

Answer 34

direct contact with eggs on people, sheets, or inhalation of airborne eggs

Question 35

how is enterobiasis diagnosed?

Answer 35

scotch tape test

Question 36

who is commonly effected by pinworms?

Answer 36

children, institutionalized

Question 37

what is the most common human worm infection? (surveillance)

Answer 37

Ascaris Lumbricoides infects 25% of world population (tropics) 50% of children in U.S.

Question 38

while many are asymptomatic, what are other potential symptoms of Ascaris Lumbricoides?

Answer 38

- damage to lungs (COUGH) - severe: malnutrition - intestinal obstruction -> death

Question 39

what type of transmission is Ascaris Lumbricoides?

Answer 39

fecal-oral; can also cough out worms

Question 40

chemo can be used to treat what?

Answer 40

roundworms

Question 41

what causes trichinellosis?

Answer 41

trichinella spiralis

Question 42

what disease is obtained from eating raw or undercooked pork or wild game infected with cysts?

Answer 42

trichinellosis

Question 43

digestive juices dissolve the hard covering of ingested cysts and emerge in intestine in which disease?

Answer 43

trichinellosis

Question 44

which disease is not typically transmitted by humans?

Answer 44

trichinellosis animals (major reservoirs) feed upon infected rodents

Question 45

Trichinellosis often presents as flu-like symptoms. What other more severe symptom presents itself and how is it diagnosed?

Answer 45

Larvae deposit into muscle. Diagnosis: muscle biopsy and blood test

Question 46

What heavy infection symptoms occur from being infected with hookworms/whipworms?

Answer 46

painful stool that contains mucus, water, and blood. rectal prolapse. mental retardation in children.

Question 47

what disease is transmitted by walking barefoot on soil that is contaminated with feces?

Answer 47

whipworm/hookworm (penetrates skin)

Question 48

Other than flu-like symptoms, what is another first sign of infection of hookworms/whipworms? What other effect can occur?

Answer 48

- itching | - physical and cognitive growth of children affected (due to malnutrition)

Question 49

what disease is spread through mosquitos?

Answer 49

Lymphatic filariasis (elephantiasis)

Question 50

what helminth disease has hope for global eradication?

Answer 50

lymphatic filariasis

Question 51

what disease has an effective single dose treatment available?

Answer 51

lymphatic filariasis

Question 52

what disease is spread by bites of blackflies?

Answer 52

onchocerca volvulus (larvae develop in 10-12 days)

Question 53

what are the symptoms of onchocerca volvulus?

Answer 53

- live under the skin and near muscles and joints, causing significant pain - thickening of cornea => "River Blindness"

Question 54

which disease is referred to as "river blindness"?

Answer 54

onchocerca volvulus

Question 55

what does the guinea worm cause?

Answer 55

Dracanulus medinensis

Question 56

what is the portal of entry and exit for dracanulus medinensis?

Answer 56

entry: drinking contaminated water exit: blister develops -> cool water to ease burning pain -> worm detects temperature change and bursts from blister

Question 57

what is the portal of entry and exit for schistomiasis?

Answer 57

- portal of entry: cercarieae penetrate skin of bathers -> migrate to blood vessels (worms feed on blood) -> invade liver - portal of exit: eggs discharged in feces and urine -> develop into Cercariae - male and female worms stay together for life cycle - infection for years