This complication occurs in approximately 1 in 1,000 infected individuals.

It may be the cause of 30 to 50% of children who have acute obstruction in areas where it is found.

Each female worm produces approximately 200,000 eggs per day with an estimated total of 27 million during its life span.

The eggs are highly resistant to adverse environmental conditions which contributes to its widespread distribution.

This is the most common intestinal worm infection of humans.

It is found in association with poor personal hygiene, poor sanitation, or where human feces are used as fertilizer.

Infection occurs when food or drink contaminated with roundworm eggs is ingested, or the worm eggs are on dirty fingers.

The eggs hatch releasing larvae within the intestine & make their way into veins.

The larvae then migrate through the blood stream to the lungs and burrow out into the air sacs.

During migration through the lungs the larvae may produce an eosinophilic pneumonia.

Once back in the human small intestine, they mature into adult roundworms.

Adult worms retain their location by actively swimming against peristaltic action of the intestine.

Adult worms mate & the female lays eggs that pass to the large intestine and are expelled with the feces.

Improved sanitation and hygiene in poverty conditions or developing countries will reduce the risk in those areas.

In areas where this disorder is common, routine or preventive (prophylactic) treatment with "deworming" medications may be advised.

Vomiting up worms

Low-grade fever

Bloody sputum

Shortness of breath

Stomach pain

Interference with nutrition by the worm interfering with absorption of food or vitamins.

Note: There may be no symptoms.

Kill the adult worms with Adeworming@ medications.

If there is an obstruction of worms in the intestine, medications which can make the worms relax and pass through the gut are given.

The probable outcome is usually good even without treatment.

However, complications may be caused by migratory adult worms which like to explore body passages.

May stop up (block) the intestine, especially when treated with deworming medication.

Hookworm is an intestinal parasite of humans that usually causes mild diarrhea or cramps.

Heavy infection with hookworm can create serious health problems for newborns, children, pregnant women, and persons who are malnourished.

Hookworm infections occur mostly in tropical and subtropical climates and are estimated to infect about 1 billion people -- about one-fifth of the world's population.

One of the most common species, Ancylostoma duodenale (an-cy-CLO-sto-ma doe-AH-den-al), is found in southern Europe, northern Africa, northern Asia, and parts of South America.

A second species, Necator americanus (ne-KAY-tor am-er-i-CON-us), was widespread in the southeastern United States early in this century.

The Rockefeller Sanitary Commission was founded in response, and hookworm infection has been largely controlled.

A person can become infected by direct contact with contaminated soil, generally through walking barefoot, or accidentally swallowing contaminated soil.

Hookworms have a complex life cycle that begins and ends in the small intestine.

Hookworm eggs require warm, moist, shaded soil to hatch into larvae.

These barely visible larvae penetrate the skin (often through bare feet) when they burrow into blood vessels.

The larvae are carried to the lungs by the veins.

They are either spit out (especially by tobacco chewersBperhaps the only benefit of this filthy habit), or are swallowed as a person feels the need to clear the throat.

The larvae go through the stomach and eventually reach the small intestine.

This journey takes about a week.

In the small intestine, the larvae develop into half-inch-long worms, attach themselves to the intestinal wall, and suck blood.

The worms get both oxygen and food from the blood so draw blood constantly through their bodies, almost like a small vein leaking blood continuously.

Adult worms may live up to 10 years, so the infection will not quickly clean up on its own.

There are separate sexes (dioecious) so they mate here.

The female worms produces thousands of eggs per day.

These eggs are passed in the feces.

If the eggs contaminate soil and conditions are right, they will hatch, molt, and develop into infective larvae after 5 to 10 days.

After becoming mature, the larvae can eat no more.

Wait for contact with bare human skin so they can burrow in and start the life cycle anew.

People who have direct contact with soil that contains human feces in areas where hookworm is common are at high risk of infection.

Children --because they play in dirt and often go barefoot-- are at high risk.

Since transmission of hookworm infection requires development of the larvae in soil, hookworm cannot be spread person to person.

Contact among children in institutional or child care settings should not increase the risk of infection.

Itching and a rash at the site of where skin touched soil or sand is usually the first sign of infection.

These symptoms occur when the larvae penetrate the skin.

While a light infection may cause no symptoms, heavy infection can cause anemia, abdominal pain, diarrhea, loss of appetite, and weight loss.

Heavy, chronic infections can cause stunted growth and mental development.

The most serious results of hookworm infection are the development of anemia and protein deficiency caused by blood loss.

When children are continuously infected by many worms, the loss of iron and protein can retard growth and mental development, sometimes irreversibly.

Stereotypes of the lazy, shiftless Southern hillbilly after the Civil War are believed to be partly due to hookworm infections.

Hookworm infection can also cause tiredness, difficulty breathing, enlargement of the heart, and irregular heartbeat.

Sometimes hookworm infection is fatal, especially among infants.

Visit a health care provider.

Infection is diagnosed by identifying hookworm eggs in a feces sample.

In countries where hookworm is common and reinfection is likely, light infections are often not treated.

In the United States, hookworm infections are generally treated for 1-3 days with prescription medication.

This medication cures 99% of people since it kills both the adult worms & their eggs.

The drugs, fortunately, appear to have few side effects, although it cannot be given during pregnancy..

Another feces exam should be repeated 1 to 2 weeks after therapy.

If the infection is still present, treatment will be given again.

Iron supplements will be ordered if the person has anemia.

Do not walk barefoot or contact the soil with bare hands in areas where hookworm is common or there is likely to be feces in the soil or sand.

A susceptible animal eat raw or undercooked meat containing the cysts (contain larvae) of the worm.

Larvae mature into adults in the host=s small intestine in a few weeks, requiring approximately 16 days to mature.

Males die after fertilizing the females.

Female trichina hatches fertilized eggs in her body.

Larvae are then deposited in the lining of the intestine of the host.

During the stage of infection, after the immature trichina worms are freed from their cysts, maturing larvae, if numerous, cause severe irritation of the intestinal tract.

The female dies after releasing the larvae.

Larvae make their way into the bloodstream where they travel to all parts of the body of the host.

With the release, or migration, of the larvae into the bloodstream, the host's face becomes puffy and swollen, especially the eyes, and headache and even delirium occur.

The worm grows within muscle tissue.

The muscles that are most often invaded by trichina worm are those of the diaphragm, eyes, neck, throat, larynx, and tongue.

A cyst, a tough fibrous tissue develops around larva=s body inside the muscle.

In the muscles, larvae cause severe host reaction that results in soreness and tenderness of the muscles.

In the muscles, larvae develop into infective larvae, and the next host is infected when it eats these larvae.

In the muscles, the larval capsules, or cysts, may remain alive for years, eventually becoming calcified.

The life cycle of trichina worm continues if the host=s muscle tissue containing the cysts is eaten.

This may be by such means as feeding raw garbage to hogs, hogs eating infected rats, cannibalism among rats, or any other means by which raw meat is eaten.

One gram of raw pork meat may contain 3,000 trichina cysts.

The worms which develop into females (about half of them) may inject 1,500 larvae before dying. Students should do the math on this one!

Trichina cysts in pork may be destroyed completely by freezing the meat at - 40 degrees for 21 days, or -80 degrees for about 25 hours. (Home freezers??)

Trichina larvae that are not encysted are destroyed when the meat is heated to 66 degrees celsius.

Trichinosis is a serious disease caused by trichina worm, that is transmitted primarily through eating raw or undercooked pork.

It is the best known as a parasitic disease that humans catch from eating raw or undercooked pork.

Through an aggressive program of meat inspection, the incidence of trichinosis in pigs in US has been lowered to less than 1%, so it is unlikely but still possible that pork products purchased by people in local supermarkets will contain Trichinella larvae.

In the US the incidence of infection as detected by finding calcified cysts at autopsy may be as high as 15 to 20%.

Despite rigid standards of meat inspection in US, infected pork can sometimes pass inspection because the disease is extremely difficult to recognize.

Most recent outbreaks of trichinosis in US have been traced to pork products from pigs that haven=t been inspected and that have been slaughtered privately.

Hunters should be careful when preparing wild meat from their kills. A number of infections have traced to contaminated bear meat.

Humans contract filariasis when they are bitten repeatedly by mosquitoes infected with filarial worms.

Over 70 species of mosquitoes infect humans with the disease.

Mosquitoes pick up the tiny, microfilarialform of the parasite when taking blood meals from infected humans.

In the mosquito, the microfilariaedevelop within 7-21 days into members of the next stage of the parasite=s life cycle, which are known as filariform larva.

The filariform larva are infective to humans.

When the larval worms move to a mosquito=s mouth, and then the mosquito bites humans, the parasites can spread through a human community.

Fortunately, however, many bites from infected mosquitoes are required before a person is infected with the disease.

Once a human does pick up filariform larvae from mosquito bites, the larvae move to the lymphatic system, where they develop into adult worms.

It usually takes 8-16 months after infection for symptoms of the disease to appear.

The life span of adult worms is approximately seven years (microfilariae have a life span of from 3-36 months).

The adults are about the diameter of coarse sewing thread & may be a few inches long.

In the human, the adult worms mate and then the females produce millions of new microfilariae, which then circulate in the blood stream.

Microfilariae circulating in the bloodstream can then be picked up by mosquitoes taking blood meals.

In most endemic regions, microfilariae show peak abundance in the human bloodstream between 10 p.m. and 2 a.m., which corresponds with the time when Culex mosquitoes are most active.

In some regions of the South Pacific, however, where the vectors of filariasis are active primarily in the daytime, microfilariae are most abundant during the day.

Lymphatic filariasis occurs in the tropics of India, Africa, Southern Asia, the Pacific, and Central and South America.

The largest fraction of cases occurs in Southeast Asia, with the second largest fraction occurring in Africa.

The disease has increased in frequency with a global expansion of urbanization; urbanization brings an increase in breeding sites for vector mosquitoes.

Screening. Screening for the disease has traditionally been difficult, requiring a microscopic examination of a blood sample.

Often, this blood sample had to be collected in the middle of the night in order to correspond with the time of peak microfilariae abundance.

However, a simple effective ELISA test for antigens of the parasite in blood samples collected any time of the day is now available, making screening far easier.

(1) getting rid of the microfilariae in people=s blood, so that the transmission cycle can be broken and

(2) maintaining careful hygiene in infected persons to reduce the incidence and severity of secondary (e.g., bacterial) infections.

Anti-filariasis medicines commonly used reduce microfilariae concentrations and also kills adult worms.

The disease is usually treated with single-dose regimens of a combination of two drugs, one targeting microfilariae and one targeting adult worms.

If a high enough coverage of anti-filariasis drug treatment can be achieved (treating greater than 80% of the people in a community), the disease can be eradicated from an area.

Attempts to reduce, and eventually eliminate lymphatic filariasis will be facilitated by the fact that humans are essentially the only reservoirs, and that the parasite does not increase in numbers in mosquitoes, but only in humans.

In addition, the inefficiency with which filariasis is transmitted (many bites from infected mosquitoes are required to infect a human) further improves the chances of eradicating the disease.

Covering water-storage containers and improving waste-water and solid-waste treatment systems can help by reducing the amount of standing water in which mosquitoes can lay eggs.

In addition, killing eggs (oviciding) and killing or disrupting larva (larviciding) in bodies of stagnant water can further reduce mosquito populations.

People in endemic areas can reduce the probability of being infected with filariasis by decreasing the number of times they are bitten by mosquitoes.

Such personal protection measures can include wearing long sleeves, applying insect repellent, using insecticide-impregnated bed nets, and remaining inside when mosquitoes are most active.

Pinworm is the most common worm infection in the United States.

School-age children, followed by preschoolers, have the highest rates of infection.

In some groups nearly 50% of children are infected.

Infection often occurs in more than one family member.

Adults are less likely to have pinworm infection, except mothers (or direct care provider) of infected children.

Child care centers, and other institutional settings often have cases of pinworm infection.

Pinworm eggs are infective within a few hours after being deposited on the skin.

They can survive up to 2 weeks on clothing, bedding, or other objects.

Persons can become infected after accidentally ingesting (swallowing) infective pinworm eggs from contaminated surfaces or fingers.

In a heavily-infested house where the sheets have just been shaken out, infection may result from simply breathingBthe eggs are breathed in and swallowed.

If pinworms are suspected, transparent adhesive tape (often called the "scotch tape test") is applied to the anal region.

The eggs become glued to the sticky tape and are identified by examination under a microscope.

Because bathing or having a bowel movement may remove eggs, the test should be done as soon as the person wakes up in the morning.

Since scratching of the anal area is common, samples taken from under the fingernails may also contain eggs.

At night, the adult worms can sometimes be seen directly in bedclothes or around the anal area.

With either prescription or over-the-counter drugs.

Treatment involves a two-dose course.

The second dose should be given 2 weeks after the first.

The infected person should be treated with the same two-dose treatment.

Close family contacts should also be treated.

If the infection occurs yet again, the parent should search for the source of the infection.

Playmates, schoolmates, close contacts outside the house, and household members should be considered.

Each infected person should receive the usual two-dose treatment.

Bathe when first get up to help reduce the egg contamination.

Change and wash underwear each day.

Frequent changing of night clothes are recommended.

Change underwear, night clothes, and sheets after each treatment.

Because the eggs are sensitive to sunlight, open blinds or curtains in bedrooms during the day.

Personal hygiene should include washing hands after going to the toilet, before eating and after changing diapers.

Trim fingernails short.

Discourage nail-biting and scratching bare anal areas to prevent self reinfection.

Guinea worm is a painful and debilitating disease whose effects reach beyond a single victim, crippling agricultural production and school attendance, for example.

A child suffers and is unable to attend school.

Or his parent suffers, unable to harvest crops or attend to younger children.

The village suffers a food shortfall when its people are unable to work.

During one year in the mid-1980s in southeastern Nigeria, rice farmers lost $20 million (U.S.) due to outbreaks of Guinea worm.