What are Parasitic Diseases?

Organisms that live off a host and derive their nutrients from them cause parasitic diseases. These parasites can be classified into broad types which include → Protozoa, helminths, and ectoparasites. Some Parasitic infections may not show symptoms, but others can make you very ill or even cause death. In this article, we’ll provide all the details about parasitic diseases.  Let’s discuss the different kinds of parasites responsible for causing these diseases and how they spread. But let’s first know what exactly are these parasites.


Parasitic Diseases

Parasitic diseases happen when organisms that live on or inside a host organism like → humans or animals, get their nutrients from them. Nature contains these organisms.  There’s a variety of sizes for these parasites starting from small, single-celled protozoa all the way up to larger worms and insects. Parasites can affect different body parts, such as → the digestive system, respiratory system, and blood, causing various symptoms.

Types of Parasites that Cause Diseases

Parasites come in many different kinds. These parasites cause different types of diseases in humans. Some common parasites are:



Tiny single-celled organisms are protozoa. It can cause diseases such as → malaria, toxoplasmosis, and amoebic dysentery. Toxoplasmosis comes from a parasite infection known as Toxoplasma gondii. Contaminated water or food typically transmits them, or an infected mosquito or tick bites and transmits them.



Worms called helminths can give you diseases like → hookworm infection, schistosomiasis, and filariasis (a disease caused by thread-like nematode worms). Contaminated soil or water can typically transmit them through touch or by consuming unclean food.



Ectoparasites, they’re parasites that live and thrive on the skin or hair of a host organism. Examples include → lice, fleas, and ticks. These parasites, such as → the bacterium Borrelia burgdorferi, can cause diseases like Lyme disease, which is a tick-borne illness. Borrelia burgdorferi is the bacteria that causes it. They cause another disease known as typhus, which infects the body and leads to flu-like symptoms. Infected insects typically transmit it through their bite.

To prevent infection and get the right treatment, it’s important for us to understand the various parasites that can cause diseases. 

In the next section, we’ll talk about the different kinds of Parasitic diseases.

Types of Parasites Diseases

Parasites are organisms that live off the host and cause diseases. Humans can be affected by various types of parasites that cause diseases. There are some parasites like protozoa, helminths, and ectoparasites.


Single-celled organisms have the ability to get many diseases including –  malaria, amoebiasis, and giardiasis.

Some of the most common protozoal infections include malaria, amoebiasis, and giardiasis:

  1. Malaria: Malaria is a life-threatening disease. It is generated by the parasite Plasmodium. It is transmitted to humans through the bite of infected mosquitoes. Malaria symptoms include → fever, chills, and symptoms similar to the flu.
  2. Amoebiasis: The Entamoeba histolytica parasite causes amoebiasis. It spreads through food and water that has been contaminated. Symptoms of amoebiasis include → diarrhea, abdominal pain, and weight loss.
  3. Giardiasis: The Giardia lamblia parasite Causes giardiasis, and it spreads through food and water that has been contaminated. People with giardiasis experience symptoms like → diarrhea, abdominal pain, and bloating.


Worms can cause diseases such as schistosomiasis, hookworm infection, and tapeworm infestation. There are several prevalent diseases related to Helminths.

  1. Schistosomiasis: This occurs due to a Parasitic worm present in tropical and subtropical freshwater. Schistosomiasis Causes Symptoms like itching, rash, and abdominal pain.
  2. Hookworm Infection: A Parasitic worm enters your body through the skin and Causes hookworm infection. Symptoms of hookworm infection include – abdominal pain, diarrhea, and weight loss.
  3. Tapeworm Infestation When you eat undercooked or contaminated meat, you can contract a Parasitic worm that Causes tapeworm infestation. This infestation leads to Symptoms like abdominal pain, nausea, and diarrhea.


There are parasites like fleas, ticks, and lice that live on the skin or fur of animals. Some of the most common Ectoparasites related diseases are:

  1. Fleas: Fleas are small, wingless insects that feed on the blood of animals and humans. Flea bites can cause itching, skin irritation, and allergic reactions.
  2. Ticks: Ticks are small creatures and arachnids that suck blood from animals and humans. Tick bites can transmit diseases such as Lyme disease and Rocky Mountain spotted fever.
  3. Lice: Small insects called lice live on human skin and hair. Lice infestations can cause itching, skin irritation, and secondary infections.

In the next section, we’re going to talk about how Parasitic diseases spread and how doctors diagnose them.

Transmission of Parasitic Diseases

Parasitic diseases pass from person to person in different ways – through contaminated food or water, by touching infected animals, or when insects bite. Let’s have a closer look at how each of these methods can lead to Parasitic infection:

Contaminated Food or Water

You can come across parasites in food and water contaminated with fecal matter, which contains eggs or cysts of parasites. This can happen due to poor hygiene, improper waste disposal, or inadequate water treatment. There are several Parasitic diseases that people can catch from contaminated food or water. People can contract several diseases, including giardiasis, cryptosporidiosis, and cholera.

Contact with Infected Animals

Parasites can also spread when you come into contact with infected animals, whether it’s direct or indirect contact. For example, infected mosquitoes or ticks can bite you and transfer a few Parasitic diseases. Another example is that other diseases can also be transmitted through contact with animal feces or contaminated soil. There are several Parasitic diseases that infected animals can transmit through contact. These are a few of many diseases –  malaria, Lyme disease, and toxoplasmosis.

Insect Bites

Insect bites can also transmit Parasitic diseases. Mosquitoes, transmit several Parasitic diseases, including malaria, dengue fever, and the Zika virus. Other insects like fleas and lice can also transmit Parasitic diseases.

Here are some common risk factors for Parasitic infection:

Risk Factors for Parasitic Infection

Several factors can increase a person’s risk of Parasitic infection. These include:

Poor sanitation

The higher chances of getting infected with parasites are contributed to by the improper disposal of waste and the lack of access to clean water. The reason behind this is that unsanitary conditions create an environment where parasites can grow and thrive, making it easier for them to spread through contaminated food or water.


People living in poverty face an increased risk of parasite infection due to factors such as lacking proper sanitation, being unable to access healthcare, and having limited resources for personal hygiene. Moreover, poverty can lead to malnutrition, weakening the immune system and making people more at risk of Parasitic infections.

Travel to Endemic Areas

Some Parasitic diseases are more common in certain regions of the world, known as endemic areas. People who travel to these regions may be at a higher risk of Parasitic infection. Endemic Parasitic diseases such as malaria, Chagas disease (a Parasitic infection caused by the protozoan parasite), and leishmaniasis are some examples.

Leishmaniasis, which is caused by the Leishmania parasite, is transmitted to humans through the bite of infected sandflies.

In the next section, we’ll discuss the symptoms and treatment of Parasitic diseases.

Symptoms and Treatment of Parasitic Diseases

Parasitic diseases are caused by organisms that live off the host and derive their nutrients from them. Parasites, these organisms, can cause humans to experience various Symptoms such as diarrhea, fever, and skin rashes.

Symptoms of Common Parasitic Diseases

The Symptoms of Parasitic diseases can vary depending on the type of parasite involved. Some common symptoms include:

  1. Diarrhea: Parasites frequently cause diarrhea, particularly when protozoa such as Giardia and Cryptosporidium infect the small intestine. They induce Symptoms like diarrhea, abdominal pain, and dehydration.
  2. Fever: Many Parasitic infections can cause fever as the body tries to fight off the infection. Infections caused by protozoa and helminths like malaria and schistosomiasis, show this to be true.
  3. Skin Rashes: Some Parasitic infections can cause skin rashes, such as those caused by the hookworm Ancylostoma braziliense (a type of hookworm that can infect humans and animals). Infections can make your skin itch, turn red, and swell.

Treatment Options

Treatment options for Parasitic diseases vary depending on the type of parasite involved. In general, treatment may involve medications and supportive care.

  1. Medications: There are many different medications that doctors can use to treat Parasitic infections. These include anti-parasitic drugs like mebendazole and praziquantel. These drugs work by killing the parasite or preventing it from reproducing.
  2. Supportive Care: In some cases, supportive care may be necessary to manage symptoms of Parasitic infections. For example, rehydration therapy may be needed to treat dehydration caused by diarrhea.

Challenges in Treating Parasitic Diseases

Treating Parasitic diseases can be challenging for a variety of reasons. One big challenge we face is drug resistance. This occurs when parasites get exposed to the same drugs repeatedly, and they develop resistance. This can make it difficult to find effective treatments for Parasitic infections.

In addition, lack of access to healthcare can make it difficult for people in some areas to receive treatment for Parasitic diseases. This can be particularly true in low-income countries, where Parasitic infections are more common and healthcare resources are limited.

In the next section, we’ll discuss the prevention of Parasitic diseases.

Prevention of Parasitic Diseases

Parasitic diseases can have a significant impact on our health, causing a range of symptoms from → mild discomfort to life-threatening illness. However, many Parasitic infections are preventable through simple measures like ensuring clean water and good hygiene practices. Here are some key strategies for preventing Parasitic diseases:

Clean Water and Sanitation

Access to clean water and proper sanitation facilities is essential for preventing many Parasitic infections. Parasites can survive in contaminated water sources, such as → lakes and rivers, and can enter the body through the mouth, causing diseases such as amoebiasis and giardiasis.

  1. To prevent Parasitic infections from contaminated water, it is important to ensure that water sources are properly treated, such as through chlorination or filtration. Additionally, individuals should avoid drinking untreated water from sources such as streams or wells that may be contaminated.
  2. Proper sanitation is also critical in preventing the spread of Parasitic infections. Human waste can contain parasites that can infect others if not disposed of properly. Proper sanitation facilities, such as toilets and handwashing stations, can help prevent the spread of Parasitic infections.

Proper Hygiene Practices

Proper hygiene practices are essential in preventing the spread of many Parasitic infections. Parasites can be transmitted through contact with contaminated surfaces or through the consumption of contaminated food.

  1. Regular handwashing with soap and water is a simple and effective way to prevent the spread of Parasitic infections. Individuals should wash their hands before eating or preparing food, after using the bathroom, and after handling animals.
  2. Food safety practices can also help prevent the spread of Parasitic infections. Individuals should ensure that food is properly cooked and stored, and avoid consuming raw or undercooked meat, fish, or eggs.

Use of Insect Repellents and Protective Clothing

Many Parasitic infections are transmitted by insects such as mosquitoes and ticks. To prevent insect bites, individuals should use insect repellents (some products that help to deter insects from biting or landing on the skin) containing DEET, picaridin, or other EPA-registered active ingredients. Wearing protective clothing like long-sleeved shirts and pants can help you avoid insect bites.

Individuals should also take steps to reduce the presence of insects in and around their homes, such as → by using screens on windows and doors and eliminating standing water sources that can attract mosquitoes.

Final Words on Parasitic Diseases

Parasitic diseases are a major public health concern that affects millions of people worldwide. Organisms that live off their host cause these diseases. They display broad symptoms, varying from mild to severe.

It is important to recognize that Parasitic diseases can be prevented through various measures, such as → practicing good hygiene, avoiding contaminated water sources, and using insecticides to prevent bites from disease-carrying insects. Additionally, continued research and development of new treatments and prevention strategies are essential to reducing the impact of parasitic diseases on global health.

Further Reading

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  1. Donald Hobern from Copenhagen, Denmark, CC BY 2.0, via Wikimedia Commons.
  2. Roland Yao Wa Kouassi, Scott William McGraw, Patrick Kouassi Yao, Ahmed Abou-Bacar, Julie Brunet, Bernard Pesson, Bassirou Bonfoh, Eliezer Kouakou N’goran and Ermanno Candolfi, CC BY 4.0, via Wikimedia Commons.
  3. Lucie Oslejskova, Sarka Kounkova, Daniel R. Gustafsson, Roberto Resendes, Pedro Rodrigues, Ivan Literak and Oldrich Sychra, CC BY 4.0, via Wikimedia Commons


kayakalp.paramedical · July 3, 2023 at 2:32 pm

Very informative article.

Akshay Sharma · June 3, 2023 at 11:55 am

I found the section on the parasitic diseases: causes, symptoms, treatment and prevention to be quite comprehensive. The article mentioned that symptoms can vary depending on the stage of the disease. Thanks for writing this kind of article.

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