Parasitic Infections

When common parasites of dogs and cats infect humans, the illness is called toxocariasis (or visceral larva migrans). Toxocariasis usually affects kids under age 10. Especially at risk are those who like to put things in their mouths, or kids whose families have pet dogs or cats.

Signs and Symptoms

Many kids won’t have symptoms, but if they do, they can include fever, cough or wheezing, abdominal pain, enlarged liver or spleen, poor appetite, a rash that sometimes looks like hives, and enlarged lymph nodes (“swollen glands”).

Toxocariasis also may affect the eyes, causing decreased vision, swelling around the eyes, or a cross-eyed appearance. Untreated toxocariasis can cause damage to the retina (the part at the back of the eye that senses light).

Most cases go undiagnosed and do not cause problems. Some toxocariasis cases are diagnosed during a routine eye exam or an X-ray study done for some other reason.

Transmission

Toxocariasis is an infection caused by the larvae of parasitic worms — Toxocara canis and Toxocara cati — that usually live in the intestines of dogs and cats. Eggs from the worms pass into the feces of dogs and cats and can contaminate pet areas around the home where kids play. The eggs can be swallowed by children, especially those who like to put things in their mouths and don’t often wash their hands.

After entering the body, the eggs hatch into larvae that penetrate through walls of the digestive tract and may migrate to a child’s liver, lungs, eyes, and elsewhere.

Toxocariasis usually happens in young children ages 2 to 7, but can happen at any age. It can’t be spread from person to person.

Prevention

To help prevent kids from being exposed to toxocariasis:

• keep them away from areas where dogs or cats play
• teach your kids to wash their hands often, especially after playing with a pet dog or cat (wash a toddler’s hands yourself)
• discourage toddlers from putting dirty hands in their mouth
• keep pets away from the sandbox and cover the sandbox when it’s not being used
• take household pets to the veterinarian to be dewormed, especially puppies younger than 6 months old
• make sure your kids don’t accidentally eat dirt or soil

Diagnosis and Treatment

A doctor can usually diagnose a case of toxocariasis by physical exam and blood tests. Doctors may not prescribe any medication to treat a child with mild symptoms. Severe toxocariasis involving the lungs, eye, or other important organs may be treated with antiparasitic drugs to kill the larvae. For severe toxocariasis, doctors sometimes also prescribe steroids or might refer a person to a specialist (like an ophthalmologist if the eye is involved).

A child with severe toxocariasis should be given medicine as prescribed by your doctor. Prevent reinfection by deworming your pets and keeping kids away from areas where pets defecate (poop). Remind your kids to wash their hands often during the day, especially after playing with pets.

When to Call the Doctor

Call your doctor if your child has any of the symptoms of toxocariasis, including:

• fever
• rash
• cough or wheezing
• abdominal pain
• poor appetite
• vision problems

Toxoplasmosis is an infection by a tiny parasite (Toxoplasma gondii) that can live inside the cells of humans and animals, especially cats and farm animals.

If you have been pregnant, you may already know it’s important to avoid toxoplasmosis, which people can develop by cleaning the litter box of an infected cat or eating undercooked meat or other contaminated foods.

The Centers for Disease Control and Prevention (CDC) estimates that about 60 million people in the United States could have toxoplasmosis, but most won’t have symptoms because their immune systems are strong.

How It Spreads

People can catch toxoplasmosis from:

• touching or coming into contact with infected cat feces (poop). A cat can become infected from eating infected rodents, birds, or other small animals.
• eating raw or undercooked meat (especially lamb, pork, and venison) from animals that were infected
• eating raw, unwashed fruits or vegetables that have touched manure
• being born with it (a woman who gets toxoplasmosis while pregnant may pass the parasite to her unborn child through the bloodstream)
• accidentally ingesting (swallowing) the eggs of the parasite, which can get on the hands after handling soil without gloves or handling uncooked, unwashed foods
• drinking contaminated water

Although infection doesn’t normally spread from person to person except through pregnancy, in rare instances toxoplasmosis can contaminate blood transfusions and organs donated for transplantation.

Signs and Symptoms

Toxoplasmosis is passed from animals to humans, sometimes without causing any symptoms. When kids do have symptoms, they vary depending on a child’s age and the immune system’s response to the infection. (Both humans and infected cats often don’t show any signs of a toxoplasmosis infection.)

Toxoplasmosis in Kids

In kids, toxoplasmosis infections can be:

1. congenital (when a child is infected before birth)
2. milder, affecting otherwise healthy kids (similar to infections in pregnant women)
3. in kids with weakened immune systems

Congenital Toxoplasmosis

When a pregnant woman (even one with no symptoms) catches toxoplasmosis during pregnancy and it’s not treated, there’s a chance that she could pass the infection to her developing fetus. Babies infected during their mother’s first trimester tend to have the most severe symptoms.

A woman who got toxoplasmosis before getting pregnant usually won’t pass the infection to the baby — this is because she (and, therefore, her baby) will have built up immunity to the infection. Toxoplasmosis can be reactivated, meaning it can come back, in a pregnant woman who’s had a previous toxoplasma infection and has a weakened immune system. Generally, it’s probably a good idea to wait to try to get pregnant until at least 6 months after a toxoplasmosis infection.

Up to 90% of children born with congenital toxoplasmosis have no symptoms early in infancy, but a large percentage will show signs of infection months to years later. Premature newborns and very small newborns show clear signs of infection at birth or shortly after.

Signs and symptoms, if they happen, can include:

• fever
• swollen glands (lymph nodes)
• jaundice (yellowed skin and eyes caused by high levels of the liver chemical bilirubin)
• an unusually large or small head
• rash
• bruises or bleeding under the skin
• anemia
• an enlarged liver or spleen

Some babies with congenital toxoplasmosis have brain and nervous system problems that cause:

• seizures
• limp muscle tone
• feeding problems
• hearing loss
• intellectual disability (mental retardation)

They’re also at high risk for eye damage involving the retina (the light-sensitive lining at the back of the eye that’s responsible for sight), resulting in severe vision problems.

If a child is born with congenital toxoplasmosis and isn’t treated during infancy, there’s almost always some sign of the infection (often eye damage) by early childhood to adolescence.

Toxoplasmosis in Otherwise Healthy Kids

A healthy child with toxoplasmosis may have no signs of infection or only a few swollen glands that:

• usually appear in the neck
• are sometimes tender to the touch
• may become larger and smaller over several months

Most healthy kids with these symptoms won’t need medical treatment unless the infection gets worse.

Toxoplasmosis in Kids With Weakened Immune Systems

Kids whose immune systems are weakened (for example, by AIDS, cancer, or medicines taken after organ transplants) are at special risk for severe toxoplasmosis infections. Especially in children with AIDS, toxoplasmosis can attack the brain and nervous system, causing toxoplasmic encephalitis (an inflammation of the brain) with symptoms that include:

• fever
• seizures
• headache
• psychosis (a type of severe mental illness)
• problems with vision, speech, movement, or thinking

Duration

Although toxoplasmosis parasites may grow and multiply within a week of entering a person’s body, it may be weeks or months before symptoms of infection appear (if they appear at all).

Once someone becomes infected with toxoplasmosis, the infection remains in the body for life, usually in a latent (inactive) form that won’t cause side effects or harm. The infection can be reactivated, however, if the immune system becomes compromised by an HIV infection or cancer therapy.

In a child with a healthy immune system, mild symptoms of toxoplasmosis (such as swollen glands) usually pass within a few months, even without medical treatment. But kids born with severe congenital toxoplasmosis may have permanent vision problems or mental retardation. And in a child with a weakened immune system, toxoplasmosis can be fatal.

Diagnosis

Doctors can diagnose toxoplasmosis through laboratory tests that check for microscopic parasites in the blood, spinal fluid, amniotic fluid, placenta, lymph nodes, bone marrow, or other body tissues.

More often, doctors order blood tests to measure the level of antibodies (substances that are part of the body’s defensive immune reaction) produced to fight the parasites.

Genetic tests can identify the DNA-containing genes of toxoplasmosis parasites once they’ve invaded the body. These tests are especially useful for checking the amniotic fluid for evidence of congenital toxoplasmosis in a fetus. Obstetricians may use ultrasounds to help diagnose congenital toxoplasmosis. But these tests aren’t 100% accurate and can lead to false-positive results, meaning there may not actually be an infection.

For babies, doctors ask the mother about things like exposure to household cats or contaminated food or water sources. Tests that might be done for these babies include eye, ear, and nervous system examinations, spinal fluid analysis, and imaging of the head to look for changes in the brain.

Treatment

Unless someone has a weakened immune system or is pregnant, there’s often no need to treat a toxoplasmosis infection — symptoms (such as swollen glands) usually go away on their own in a few weeks or months. However, kids should always be checked by a doctor because swollen glands can be a sign of other illnesses.

If a pregnant woman gets infected, her doctor and an infectious disease specialist work together to create a treatment plan. Research has shown that treating the mother can help make the infant’s disease less severe, but it won’t necessarily prevent the infant from getting toxoplasmosis.

Children born with congenital toxoplasmosis are treated with different combinations of anti-toxoplasmosis medications, usually for 1 year after birth. A specialist will decide which medicines to use and for how long.

In healthy older kids who develop serious toxoplasmosis infections, treatment usually lasts 4 to 6 weeks (or for at least 2 weeks after symptoms are gone). Kids with weakened immune systems often need to be hospitalized when they develop toxoplasmosis, and those with AIDS may need to take anti-toxoplasmosis medication for life.

When to Call the Doctor

Call your doctor right away if your child develops symptoms of toxoplasmosis and any of the following:

• is already being treated for AIDS or cancer
• has a condition that affects the immune system
• has been taking medicines that weaken the immune system

Also call the doctor if you are concerned that your otherwise healthy child may be sick with symptoms of toxoplasmosis.

If you’re pregnant, call your doctor right away if you notice even one swollen gland, especially if you’ve been exposed to cats or have eaten raw or undercooked meat.

Prevention

If your cat is kept indoors and never fed raw or undercooked meat, then your family’s feline probably has a low risk of catching or spreading toxoplasmosis. Still, you can also catch it from eating raw meats or uncooked produce that’s contaminated.

To help prevent toxoplasmosis in your family:

Food Tips

• Cook meats thoroughly.
• Wash your hands with soap and water after handling raw meat or unwashed vegetables.
• Wash all fruits and vegetables before serving. You may also want to peel them.
• Freeze meat for a few days before cooking it, which helps to reduce the likelihood of toxoplasmosis infection, says the CDC.
• Never wash raw chicken. Washing raw meat and poultry can spread germs around the kitchen. Germs are killed during cooking when chicken reaches an internal temperature of 165°F (74°C). So washing doesn’t help.
• Thoroughly wash all cutting boards, utensils, and kitchen surfaces (especially those that come into contact with raw meat) with hot soapy water after each use.
• Cook all meats completely (the juices should be clear and there should be no pink areas).

Cat Tips

• If you’re pregnant, have someone else change your cat’s litter box daily. And ask that he or she use detergent and hot water to clean it, then wash his or her hands after changing the litter. If you are unable to have someone else change the litter box, wear gloves when you do it and wash your hands thoroughly afterward.
• Keep your cat inside at all times to keep your pet from getting toxoplasmosis from the soil and/or small infected animals it tries to catch or eat.
• Keep your child’s outdoor sandbox covered, especially overnight, to prevent wandering cats from using it as a litter box.
• Don’t feed your cat raw meat.
• Steer clear of stray cats.
• Don’t take in a new cat if you’re pregnant.

General and Household Tips

• Wear gloves when gardening and wash your hands afterward.
• Use window screens to try to keep your home bug-free (cat feces are a favorite haunt of flies and cockroaches and the bugs can spread the feces, and the toxoplasmosis, onto food).
• Don’t drink untreated water, especially if you’re traveling in underdeveloped countries.

Trichomoniasis, one of the most common sexually transmitted diseases (STDs), is caused by a parasite called trichomonas vaginalis. This parasite can live in the urogenital tract of males and females and infect any sexually active person, especially those who are not using protection or who have multiple partners.

Trichomoniasis (often referred to as “trich” — pronounced “trick”) is usually treated with prescription medication. An infection can be uncomfortable and can make someone who has it more susceptible to human immunodeficiency virus (HIV), the virus that causes acquired immune deficiency syndrome (AIDS).

The only way for anyone to completely prevent infection is to abstain from sex. It’s important for sexually active teens to understand the importance of always using condoms, which can help protect against trichomoniasis and other STDs.

Symptoms

Symptoms of trich can appear as early as 5 days after sex with an infected partner. But trichomoniasis often goes undiagnosed because symptoms may not appear until later, if at all.

In females, symptoms can include:

• abundant or frothy vaginal discharge ranging in color from gray to green to yellow, with a watery to milky consistency
• foul smelling vaginal discharge
• itching and tenderness in or around the vagina
• pain during sex
• bleeding after sex
• pain during urination
• soreness or itching of the labia and inner thighs
• swollen labia

If you have a teenage daughter, it’s important for her to recognize both a normal vaginal discharge (it’s usually clear or whitish, has no bad odor, and causes no irritation) and one that might signal a problem.

Males who have trichomoniasis often don’t show any symptoms. But if they do, symptoms can include:

• mild urethral itching
• mild burning after urination or ejaculation
• painful or difficult urination
• inflammation of the prostate gland
• pain and inflammation of the scrotum

Prevention

Because trichomoniasis is an STD spread through sexual contact, the best way to prevent it is to abstain from having sex. Sexual contact with more than one partner or with someone who has more than one partner increases the risk of contracting any STD.

When properly and consistently used, condoms decrease the risk of STDs. Latex condoms provide greater protection than natural-membrane condoms. The female condom, made of polyurethane, is also considered effective against STDs.

Using douche can actually increase a female’s risk of contracting STDs because it can change the natural flora of the vagina and may flush bacteria higher into the genital tract.

A teen who is being treated for trichomoniasis also should be tested for other STDs, and should have time alone with the doctor to openly discuss issues like sexual activity. Not all teens will be comfortable talking with parents about these issues. But it’s important to encourage them to talk to a trusted adult who can provide the facts.

Treatment

The doctor can determine whether there is a trichomoniasis infection by performing a pelvic or genital examination and by testing a sample of vaginal or urethral discharge. In females, the infection also may be detected on a Pap smear.

Trich can be treated with prescription medications. Both sexual partners should be considered infected and treated at the same time, even if one has no symptoms.

Because many STDs might not cause obvious symptoms, teens often don’t know when they’re infected. It’s important for all teens who have had sex to get screened regularly for STDs so that they don’t lead to other more serious health problems.

Getting Help

If your teen is thinking of becoming sexually active or already has started having sex, it’s important to talk about it. Make sure your teen knows how STDs can be spread (during anal, oral, or vaginal sex) and that these infections often don’t have symptoms, so a partner might have an STD without knowing it.

It can be difficult to talk about STDs, but just as with any other medical issue, teens need this information to stay safe and healthy. Provide the facts, and let your child know where you stand.

It’s also important that all teens have regular full physical exams — which can include screening for STDs. Your teen may want to see a gynecologist or a specialist in adolescent medicine to talk about sexual health issues. Community health organizations and sexual counseling centers in your local area also may be able to offer some guidance.