Test One Flashcards
What is the scientific name for pinworms?
Enterobius vermicularis
Where do the larva of pinworms hatch?
Small intestine
What is the difference between male and female pinworms?
Female is much larger than the male. male is also more curly.
Where do adult pinworms live?
Large intestine. specifically the cecum
How long does it take for pinworm eggs to embryonate?
4-6 hours
How long is the pinworm life cycle?
2-4 weeks.
Describe the life cycle of pinworms.
Embryonated eggs are eaten. They hatch in the small intestine and the larva begin growing. They reach the L5 stage in the large intestine. The females crawl out of the anus and lay their eggs, or more correctly explode their uterus. Itching by the affected person and then contact with the mouth re-infects the person.
Define retroinfection
Larva that come from eggs hatching around the anus crawl back into the host.
What is the most common helminthic infection in the US?
Pinworm infection.
How long is a fully grown female? Male?
Female: 8-12 mm, Male: 2-5 mm
What are coprolites?
ancient poo
What is the distribution of pinworm infections?
20 million in the US, 200 million worldwide. Found in 10,000 year old coprolites. Primarily infects school children.
What are the clinical manifestations of a pinworm infection?
Pruitis ani (itchy butt)
Vaginitis
Irritibility, insomnia, bed wetting
Secondary perianal rash and infection
How long will pinworm eggs remain viable?
for up to a week in cool, moist environments
What is required for a laboratory diagnosis of pinworms?
Female in perineum area. Eggs around the anus
Describe the pinworm eggs
Clear shell, planoconvex shape. 20X50 micrometers
Describe the method of collecting pinworm eggs for diagnosis
Scotch tape on a stick. Stick it between the perianal folds and then stick the tape on a microscope slide.
Also can do a fingernail scraping
Define “alae”
Fins seen in a cross section of a pinworm in tissue.
What is the treatment for pinworm infection?
Mebendazole. repeat in two weeks. Leave house for a week to give enough time for the eggs to die.
What is the connection to D. fragilis
D. fragilis (a single celled parasite) can be transmitted by pinworm eggs.
What is the scientific name for whipworms?
Trichuris trichiura
Describe the shape of a whipworm.
Looks like a whip. Head end is skinny and the tail end is thick.
How long can an adult whipworm grow?
3-5 cm
Where do whipworm eggs embryonate? how long does it take to embryonate?
Embryonate in the soil. Takes around 3 weeks
How long does it take a whipworm to mature?
3 months
How long does a whipworm live?
1-8 years.
Describe the life cycle of Ascaris lumbricoides.
Eggs embryonate in the soil and are eaten. They hatch in the stomach and penetrate the intestinal wall. They get into the blood stream where they travel around until they get to the liver. They molt in the liver, penetrate the tissue and migrate to the lungs. In the lungs they go up the trachea in mucus and are swallowed. Become adults in the large intestine.
How soon after the initial infection will ascarids begin shedding eggs?
60 days
How long does it take for ascarid eggs to embryonate?
10-20 days
How many eggs can be passed each day during an ascarid infection?
200,000. a single female may contain 27 million eggs at a time
What are some of the problems associated with an ascarid infection?
Milk spot liver. Verminous pneumonia. Intestinal blockage. Malabsorption of nutrients. Possible peritonitis if the worms migrate after some sort of trauma
How long can adult ascarids get?
15-40 cm
What is the ascarid found in pigs?
Ascaris suum
How do ascarid worms stay in the intestine?
swim upstream.
How long do ascarids live for?
6-18 months
How long can ascarid eggs stay infectious for>
2 months to 6 years
What is the distribution of ascarids?
poorly sanitzed areas. Warm, moist, and shady climates. One billion people affected world wide
What are the early clinical signs of an ascarid infection?
Pneumonia, fever, coughing, wheezing (thumps in pigs), larva in sputum. Can be asymptomatic with small amounts of worms.
What are the later clinical signs of an ascarid infection?
Abdominal pain, Malnutrition, intestinal obstruction, growth interference. Can have as many as 2000 worms per person
What will a lab look for in a diagnosis?
Larva in sputum, eggs in feces, Eosinophilia during larval migration.
What do ascarid eggs look like?
Lumpy
WHat is the ascarid that infects dogs and cats?
A. canis and A. cati
What are the two hookworm genus and specie names?
Necator americanus and Ancylostoma duodenale
How can one differentiate male and female hookworms?
Males have the copulatory bursa on their tail; females just have a conical tail.
Describe the hookworm life cycle.
Mature adults live in the intestine of humans. Eggs are shed in the feces. In a warm, moist, shady environment the eggs hatch and the worms undergo a series of molts until they are infective. The host steps on them and they burrow through the skin getting into the blood stream and following it until they reach the lungs. After migrating up the lungs they are coughed up and swallowed. In the large intestine is where they become mature and start shedding eggs.
Describe arrested development.
Eggs that are in drier environments will freeze until more desirable conditions occur (like a rainy season).
What is the most common iron deficient anemias in the world?
Hookworm infections
Describe N. americanus.
Two cutting plates. Most common hookworm infection in the world. drink .03 ml of blood per day. First found in the americas but later found to be indigenous to africa and asia. live 3-5 years
What was the rockefeller foundation started up for?
To eliminate hookworm disease.
What are the 3 factors affecting hookworm infection?
- Type of hookworm
- Nutritional condition of the affected person.
- Number of worms that get inside the person.
Hookworm:
Describe the cutaneous phase.
Repeated infections can lead to hypersensitivity.
Hookworm:
Describe the pulmonary phase.
Usually asymptomatic. Maybe a sore throat and coughing.
Hookworm:
Describe the intestinal phase.
Hookworms latch onto the intestinal wall and suck blood. During a heavy infection a person can lose 200 ml of water per day.
Describe a heavy infection by hookworms.
Protein deficiency. pot belly in children. Delayed puberty, mental dullness due to iron loss. Can lead to heart failure and death.
Describe Ancylostoma duodenale
4 teeth on the top of the mouth. sucks up to .2 ml of blood per day. can lay up to 20,000 eggs per day
What is the disease impact by hookworm infection?
700 million people infected. 7 million liters of blood lost per day
Describe a hookworm egg.
lumpy looking. Clear shell surrounding it
Describe the life cycle of Wuchereria bancrofti and Brugia malayi.
Mosquito sucks blood and ingests the immature form of the worm. The worm molts and grows in the mosquitos gut. travels to the thoracic muscles and molts. Moves to the mosquitos salivary glands. The mosquito bites a human and injects the worm which travels to the lymphatic system and becomes an adult.
How long does it take for Wuchereria bancrofti and Brugia malayi to mature?
About 5 months
How long to females release babies for?
5-15 years
Differentiate between Wb and Bm
Wb is slightly longer than Bm (260mm compared to 220 mm). Wb has no terminal nuclei, Bm has 2
How long does it take for the worm to grow to filiariform larvae?
10-11 days
Differentiate the types of areas where Wb and Bm live.
Wb prefers to live and breed in densely populated areas, while Bm lives in rural areas.
What are the symptoms of a Wb of Bm infection?
Light infections can be asymptomatic. heavier ones can produce fevers, chills, sweats, muscle pains, swollen tender lymphatics, enlarged tender nodes.
What is elephatiasis?
When the lymph ducts get blocked up by a dead worm and inflammation. Edema. Happens in legs breasts and genitals
Define chyluria.
Lymph in the urine
What are the laboratory findings with a Wb infection.
Eosinophilia. Dilated afferent lymph vessels. Microfilariae in the blood (best checked between 10 pm and 2 am), also come into blood 60 min after DEC (kills adult and juvenile worms) admin. Microfilariae in the lymph. Adults in the lymph nodes.
Treatment for Wb
DEC, surgery for the elephantiasis, andtihistamines, steroids. Prevent by mass treatment and mosquito control.
