What Are The Symptoms And Treatments For Parasites?

What are the symptoms of parasites? Is there any accurate blood or stool test to detect them? What tests should I request? Is there treatment and can this be cured? Is it a risk if I get pregnant and have parasites in my blood or stools?

The field of parasitology is such an enormous one, and the number of parasites that infect humans is so great, that I had second thoughts about answering this question, but decided to go ahead in the hopes of clearing up a little bit of the confusion.

A parasite is any living organism, larger than a fungus, a bacterium, or a virus, that lives in or on humans and feeds on them. Parasitic diseases have been an extremely serious problem for humans throughout recorded history, and some of them, such as malaria, are causing serious infections in many more people than only 30 years ago. Malaria kills an estimated million children every year in Africa alone.

Parasites can live on or in the skin, in any of the body tissues, in the intestines, or in the vagina of women. The most common skin parasites are insects and include the various forms of lice and scabies. These are spread by close, not necessarily sexual, contact with other infected persons. Head lice are common among school-age children and are also seen in people who are debilitated or living in crowded conditions with poor bathing facilities. In the U.S., lice usually do not carry other diseases, but historically lice-borne infections, such as typhus, have caused major epidemics. The scabies parasite does not carry other infections but can cause an intensely itchy rash.

Single-cell parasites are called protozoa, and this group includes the amoebae; all the malaria species; pneumocystis carinii, a common infection in AIDS; toxoplasma, which can cause serious disease in AIDS patients and newborn children; cryptosporidium; and the vaginal parasite trichomonas.

Most amoebae are spread through water and food, and these parasites have become less common with improved sanitation. Cryptosporidium, which also spreads through the water supply, has caused several outbreaks in the U.S. recently and appears to be harder to eradicate from the water supply than the amoebae. Most healthy adults recover from cryptosporidium with no ill effects, but it can be a serious problem in people with HIV.

Toxoplasmosis is fairly common in humans. It can live in many animals, but in the U.S. it is most commonly caught from cats. If a pregnant woman catches toxoplasmosis, it can be passed to her unborn child and cause serious disease. Most obstetricians will routinely test for toxoplasmosis with a blood test during pregnancy, and pregnant women are advised to avoid close contact with cats, especially with the litter box.

Pneumocystis is a protozoan which is found in humans worldwide. Probably all of us carry pneumocystis from time to time, and our normal immune systems keep it under control. In people whose immune systems have been damaged by HIV infection or cancer chemotherapy, however, the parasite can cause a devastating pneumonia.

Malaria, the most widespread and deadly parasitic infection, used to be quite common in the U.S. Workers digging the Erie canal in upstate New York during the last century were plagued by malaria. We usually think of it as a tropical disease, and certainly most industrialized countries have successfully abolished it, but the mosquitoes that spread malaria are still present in the U.S. Many experts are concerned that, with increasing foreign travel, the parasite could become reestablished here. Several cases have been reported in people who had not travelled out of the U.S., so some local transmission has definitely occurred.

Some parasites, such as toxoplasmosis, can be identified by a blood test, and some, such as the amoebae and cyptosporidium, are found in the stool. Every parasite is different, and there is no easy single way to check for all of them.

In addition to insect parasites and protozoa, there are many infectious worms throughout the world, and their life cycles and modes of transmission can be extremely varied and complicated. Almost all of them must pass through another organism — a fish, snail, cow, or pig — in order to infect a human. We catch them by eating infected pork, beef, or fish, or by bathing in water containing the snail. Some are spread (not in the U.S.) by biting flies, such as river blindness in Africa, or mosquitos which transmit filiriasis in Africa and Asia.

In the U.S., most worm infections are intestinal: that is, the worm winds up living in our intestines, sharing our food, and excreting its eggs in our feces. Since fecal transmission is crucial to many of them, improved sanitation has resulted in a much lower rate of infection than in the recent past. I can remember my mother describing how she passed a long tapeworm when she was a child. I have personally seen quite a few ascaris infections, and pinworm infections are very common in children.

Ascaris is a roundworm which is occasionally passed live; people will see it moving around in the toilet and be totally freaked out. Fortunately, mild ascaris infections do not cause symptoms, are not dangerous, and will die out even if left untreated. The treatment is also safe and simple.

Pinworms are small thread-like roundworms that live in the rectum and come out at night to lay their eggs around the anus. They mostly infect kids, but since the eggs tend to float around in the air, adults in the same household can swallow them and become infected. Many infected people can feel the worms as small itchy things moving around in the rectum. The treatment is easy and safe, but everyone in a household needs to be treated at the same time. Since the eggs hang around in the air and in dust, a second treatment may be necessary. Although annoying, these worms do not cause any serious disease.

Trichinosis, a roundworm infection that is not transmitted through feces, remains a problem in this country. Most cases arise from eating undercooked pork containing the larvae of the trichinae worms. These larve mature in the intestines and burrow through the body to muscles, where they form new cysts. Light infections do not cause symptoms, and many people who were never known to have trichinosis can be found to harbor the cysts if carefully examined during an autopsy. Heavy infections can cause serious disease and even be fatal. Most cases now arise from homemade pork products, such as sausage, which have not been totally cooked. Bear and walrus meat (I know you all eat a lot of walrus) may also transmit it. Thorough cooking, freezing pork at -15 degrees centigrade for three weeks, or radiation treatment will all kill the larvae.

There have been reports in recent years of more exotic roundworm infections that people have caught from eating sushi. Many worm infections do pass through fish, especially freshwater fish. Sushi that is prepared by an inexperienced chef can contain the larvae of the worm. Some experts say one should never eat raw fish, others eat only sushi made from ocean fish but not freshwater fish, and others feel that if one patronizes a sushi chef who is skilled, he/she will be protected from infection. I personally eat sushi and love it, but I don’t worry much about parasites.

The information provided on Health Search Online is for educational purposes only and is not a substitute for medical advice, diagnosis or treatment.