Parasites

Recently I’ve seen an uptick in patients complaining of parasites. It’s become a popular topic on social media, including lots of information/misinformation on platforms like Tik Tok. At the same time, there’s been no appreciable increase in the actual number of cases of parasitic disease, and actually, parasitic diseases in Southern California are quite rare. What are the signs and symptoms of a parasitic infection?

Parasitic infections are diseases caused by organisms living and reproducing in another living thing. An infection can cause fever, fatigue, intestinal symptoms, skin rashes, and neurological symptoms. You can get them from contaminated food, water or surfaces, insect bites, fecal material, eating undercooked meat or other contaminated foods, and unprotected sex.

There are three types of parasitic infection:

• Protozoal infections are single-celled parasites. They can infect the blood, intestinal tract, brain, skin, eyes, and other parts of our body.

• Helminth is a general term for parasitic worms. They are further classified as flukes, tapeworms, roundworms, and thorny-headed worms. Worms usually infect the intestinal tract, but they can also infect skin, brain and other tissue.

• Ectoparasitic infections are insects and arachnids that live on or burrow into the skin. They include ticks, mites, lice and fleas.

Worldwide, the most common parasitic infection is caused by intestinal worms like ascaris, which affect more than a billion people each year. In addition, in 2024, 282 million people suffered from malaria. Other common parasitic infections include toxoplasmosis, head lice, giardiasis, pinworms, trichomoniasis, cryptosporidiosis, cysticercosis, and tapeworm.

Living in California, most of us have never seen a case of malaria or ascaris. The most commonly seen parasitic infection here is Chagas disease, with an estimated 70,000 to 100,000 people infected by the feces of the “kissing bug” (triatomine bug). This is more than in any other state; lucky us. I would suspect Chagas disease if a patient had unexplained heart failure, arrhythmias, severe gastrointestinal issues, fevers, fatigue, or eyelid swelling. Geographic risk factors would include those who have recently travelled to rural areas of Mexico or Central America, those who live near wilder, rural, or foothill areas, or those who are frequent campers. Chagas disease can be diagnosed with a blood test, and is treated with antiparasitic drugs.

Other common parasitic infections in Southern California include giardia and roundworms. Giardia infections come from drinking contaminated water or swimming in contaminated waters. Roundworm infections often start with our pets, and are then transmitted to their humans. Some parasitic diseases are spread through sexual intercourse, and include trichomoniasis, pubic lice (crabs), and scabies.

Please note that each parasitic infection causes a specific set of symptoms, and can be diagnosed through proper testing (including stool, blood, biopsy, sputum, body fluid, or X-rays). Unlike what many Tik Tok videos imply, they do not just live in the body without making themselves known. Treatment involves some very effective medications that often come with significant side effects, so a patient would only be treated after a proper diagnosis.

Prevention focuses on washing hands frequently and practicing safe food habits (proper storage, cooking, and washing and peeling fruits and vegetables). Travelers and those in the outdoors need to boil or treat drinking water, avoid swimming in known contaminated waters, wear protective clothing, use bug spray, and sleep under mosquito netting. Practicing safe sex is important, including condom use.

In Southern California, parasitic infections are seen relatively infrequently. However, if you have traveled to high-risk areas and have developed new and unexplained symptoms, I urge you to see your doctor.