Parasitic infections are a group of diseases transmitted and caused by parasites. These organisms live on or inside other organisms – namely, humans – who serve as hosts to parasites and provide them with food and a growth-supporting microenvironment. Some parasites do not have much visible or perceptible effect on the host’s health and can co-exist with the bearer quite peacefully for many years or even the entire life. Others, however, tend to grow, multiply, and invade vital human body systems, discharging toxins, making their hosts sick, and – sometimes – even causing their death.

The three predominant classes of disease-causing parasites in humans are helminths (worms), ectoparasites (mites, ticks, mosquitoes, lice, fleas), and protozoans (single-cell organisms). Regarding their survival mode, parasites can be divided into two groups: endoparasites that reside inside the host and ectoparasites, which live on the human skin permanently or occasionally derive their nourishment from it. Endoparasitic infections tend to have a more severe health impact. Ectoparasites, while less detrimental to the health of an individual, might be transmitting agents of certain dangerous pathogens, such as malaria or Dengue virus, and thus present a greater risk to public health in general.

How big is the problem of parasitic infections in the USA and worldwide?

Despite how advanced our medicine has got today and how progressive modern treatments are, parasitic infections remain a worldwide health concern that harms around 1.7 billion people and causes over a million deaths each year. While diseases caused by parasites are not as common a problem in the United States as in less developed countries, there are still areas – impoverished urban zones, USA-Mexico borderland regions, and river deltas – where these infections are widely present.

Statistically, people at the most risk for catching a parasitic disease are the ones who travel to developing or underdeveloped countries, immigrants, racial minorities, individuals that live in adverse hygienic conditions, and those without access to proper medical care. However, although parasitic infections have distinctive socio-economic, ethnic, and geographical preferences, they still affect people from every income and social class. The only way to stop the spread of such diseases and protect public health on a more global scale is through efficient prevention and diagnostics measures and the increased availability of modern treatments.

Signs and Symptoms of a Parasitic Infection

It is not always possible to know you have a parasite until properly tested at a medical facility. The signs and symptoms of a parasitic disease vary greatly, depending on what type of infection it is and what organisms caused it. For instance, trichomoniasis – an STD triggered by parasites- is often asymptomatic, except for infrequent itch, mild reddening of tissues, and unusual genital discharge. On the other hand, a protozoan infection like cryptosporidiosis may be accompanied by some prominent symptoms, such as stomach pain and spasms, diarrhea, vomiting sickness, fever, dehydration, and rapid loss of weight.

Still, there is a wide range of nonspecific symptoms that can point to a parasitic infection being present in the human. The problem is that since these symptoms are nonexclusive, they can be confused for other diseases like gastrointestinal problems, food poisoning, flu, etc. It once again shows the importance of due prevention and timely diagnostics efforts.

The most widespread symptoms of a parasite-caused disease are as follows:

  • Abdominal spasms and pain
  • Nausea and vomiting
  • Loss of appetite and dehydration
  • Loss of weight
  • Digestive disorders
  • Skin problems (itch, redness, hives, blistering)
  • Swelling in the lymph nodes
  • Joint or muscular pain
  • Excessive fatigue and sleepiness
  • Feeling hungry even after consuming a big meal
  • Anemia
  • Anxiety and depression
  • Trouble falling asleep and sleeping
  • Mood swings
  • Repetitive candida infection
  • Continuous and increasing itching in the genital area.

The majority of the above symptoms can easily be misinterpreted for signs of different, non-parasitic diseases, which leads to delays in treatment and further aggravation of the patient’s condition. People who suspect they might have contracted a parasite should promptly see a specialist and start the therapy as soon as the diagnosis has been confirmed. Self-treatment of individual parasitic infection symptoms, in most cases, turns out to be ineffective and cannot be a substitute for targeted medications prescribed by a licensed physician or infectious disease doctor.

What should give you the idea it might be a parasitic disease?

Here are the five main reasons to believe that your symptoms might be caused by a parasite:

  1. You recently traveled abroad, specifically, to tropical or subtropical countries and regions where you got a severe diarrhea episode.
  2. You got a new pet or recently contacted a farm animal.
  3. You swam in lakes, ponds, or rivers where parasites are common.
  4. Your work involves dealing with soil or feces.
  5. You recently had unprotected sexual contact and have been having unusual and worrying genital symptoms ever since.

How to Treat Parasitic Infections?

The plan of treatment that your doctor will choose for you will depend on the precise, lab-confirmed diagnosis. For the most part, such diseases call for the use of specifically designed antiparasitic medications – sometimes – with the addition of other, more general therapies to address certain persistent and bothering symptoms like diarrhea that can lead to dehydration if it goes untreated.

Top-5 most popular parasitic infection drugs

The most commonly prescribed drugs for the treatment of parasite-caused diseases fall into three main classes: antiparasitic meds, nitroimidazoles, and pyrethroids.

  1. Stromectol (ivermectin)

Stromectol is an anti-infective, anthelmintic prescription medication used to treat the symptoms of certain parasite-caused diseases, such as river blindness and strongyloidiasis. A single dose of Stromectol is usually enough to eradicate the roundworm in the individual’s small intestine. If the infection is extensive, the doctor may choose to prolong the course of treatment for the patient. As an off-label medication, Stromectol may also be effective against head lice, filariasis, and scabies. For more information visit product page.

  1. Albenza (albendazole)

Albendazole is a popular broad-spectrum antiparasitic medication prescribed for the treatment of infections caused by pork and dog tapeworms, including neurocysticercosis, hydatidosis. It also can be used off-label to treat patients infected with whipworms, G. lamblia, roundworms, and pinworms. When combined with some other topical treatments, albendazole can help with crusted scabies, head lice, and intestinal myiasis.

  1. Flagyl (metronidazole)

Metronidazole is an effective nitroimidazole antibiotic drug that treats certain kinds of parasitic diseases and anaerobic bacterial infections. The drug has shown great efficacy in eliminating the symptoms of Giardia infections, amebic liver abscess, intestinal amebiosis, BV, and trichomoniasis. Metronidazole is sometimes ordered for patients with Clostridioides difficile-caused infections of the colon.

  1. Vermox/Emverm (mebendazole) 

Mebendazole is prescribed for treating intestinal infections caused by worms (pinworms, hookworms, whipworms, and roundworms). This antiparasitic kills various bowel worms with only a few doses and is safe to use in patients over two years old.

  1. Piperazine

Piperazine is a time-tested anthelmintic medicine that eradicates roundworms and pinworms. Currently, the drug is getting less used worldwide, mainly because it needs repeated doses to be effective.

How to Protect Oneself against Parasitic Infections?

While it is impossible to shield oneself from parasites completely, there are a few efficient steps people can take to lower the risk of getting such an infection:

Improve personal hygiene.

Sticking to good personal hygiene habits can help ward off many dangerous parasite-caused infections and reduce the likelihood of your passing on parasites to others. To avoid getting sick, here are a few tips that can help:

  • Wash your hands well and regularly.
  • Clean and dress all cuts in a timely fashion.
  • See a doctor if the wound is deep and slow to heal.
  • Do not let anyone else use your dishes, cutlery, glasses, toiletry, and personal care items.
  • Do not use napkins, tissues, or any similar items once others have used them.
  • Cover a sneeze or a cough with a tissue, or use your elbow.

Exercise reasonable food safety.

Many parasites come from food that is consumed raw or undercooked. You can prevent such infections by storing the food properly, washing it thoroughly, and cooking it to the intended temperature. Here are a few things that will help you stay safe:

  • Wash meat, fish, domestic fowl, vegetables, and fruits under running water for a decent amount of time.
  • Rinse your hands with soap and hot water after you have been in contact with raw fish or meat.
  • Do not store raw food and prepared meals close together, and do not use the same cutlery to handle those.
  • Never defrost raw meat, fish, or other deep-frozen foods outside the fridge or microwave.

Vaccinate in time.

Apart from maintaining good personal and food hygiene, getting vaccinated in time is the next most essential thing to do if you want to stay parasite-free. Immunization keeps many infections at bay on both personal and public health levels. Make sure to talk to your health care provider about how you can keep your vaccinations up-to-date.

Take proper travel precautions.

When traveling to a country where parasitic infections are commonplace, it is crucial to take preventive measures that will allow you to stay safe and free of parasites:

  • Receive all the required immunizations in due time.
  • Use a DEET repellent when visiting a country with high numbers of insect-borne disease cases.
  • Try not to do any vaccine shots, immunizations, surgeries, or tattoos in a foreign country.
  • Take your drinks without ice unless you are 100% sure the water used is purified.
  • Drink clean bottled water only or boil it yourself if possible.
  • Clean local fruits and vegetables with anti-bacterial wipes before consuming those.
  • Do not eat raw fish, meat, or dairy products when traveling abroad.
  • Avoid accidentally swallowing water from lakes, ponds, seas, and oceans.

Engage in safe sex only.

Practicing safe sex with only one partner who you trust is the best way to avoid catching a parasitic infection and other STDs. Get yourself and your sexual partner tested regularly and use condoms every time.

Get professional medical help early.

If you are experiencing any unusual symptoms that make you suspect you might have caught a parasitic infection, contact your health care provider and get the necessary treatment as early as possible. Avoid self-diagnosing a parasite-borne disease or self-prescribing medications to treat it.

Frequently Asked Questions

Below are some of the most frequently asked questions regarding how parasitic infections spread and operate inside a human body and what methods modern medicine has to diagnose them.

Can house pets transmit parasites to humans?

Yes, pets can be infected with intestinal worms (roundworms, tapeworms, hookworms, and whipworms) and pass parasite eggs to humans through feces. Besides, some external parasites like ticks, fleas, and mites can also endanger people.

What is the deadliest parasite in the world?

It is hard to name an absolute winner in such an ominous competition, but here are the three most dangerous parasites that can easily damage the human body beyond repair:

  • Halicephalobus gingivali is a soil-dwelling nematode that mainly affects people with a compromised immune system. The meningoencephalomyelitis (brain and spinal cord inflammation) that it causes is lethal in 100% of cases. It comes through contaminated food and skin tears.
  • Naegleria fowleri is a brain-eating single-celled amoeba that causes meningoencephalitis and many other severe and painful neurological symptoms. The mortality rate is at 97%.
  • Cryptostrongylus pulmoni is a microscopic roundworm that travels in the bloodstream and severely impairs the brain functions of the host with the biological molecules it secretes. Patients are often late to start showing symptoms, which makes the disease harder to diagnose and treat.

How to diagnose a parasitic infection?

Many lab tests can be effective in confirming a parasite-caused disease. Your health care provider will determine which kinds of tests to try, depending on your symptoms, concurrent conditions, travel history, etc. The most common diagnostic methods include a stool exam, endoscopy, colonoscopy, blood tests, X-ray, MRI, and CAT scans.

Liability disclaimer

It’s important to note that this article is presented for educational purposes exclusively. We are not responsible for the accuracy or relevance of the information regarding Parasitic infections and its consumption. The article shouldn’t be viewed or used as a substitute for professional medical advice, as it is up to your doctor to decide whether the medication is right for you. We encourage you to always consult a professional before taking any medications. The information in this article is generalized, so it won’t apply to every patient. You should keep in mind that self-treatment can be dangerous for your health, as you may not be aware of all the necessary precautions.