Helminths are the worm like parasites that live on host body and gain food and protection .Helminth are the invertebrate with long flat and round bodies.

By Sadia Ghazanfer1*, Muhammad Sohail Sajid1 Muhammad Zeeshan2

There  are several distinct types of helminth, ranging in size less than one millimeter to over one meter. Helminths are parasites that infect a variety of hosts, including humans. Their impact on their hosts varies as well, causing a wide range of ailments, from minor to potentially fatal. Helminths are one of the leading causes of morbidity in the developing world, affecting more than two billion people. That equals to about one-third of the world’s population. Infection can impede physical, nutritional, and cognitive development in young children. The worldwide burden of helminth illness outnumbers that of Malaria and Tuberculosis.

The following is an introduction to some of the most well-known helminth worms. They are classified based on their overall form and the portion of the host in which they tend to influence and live during infection.

Round worm

Roundworms, sometimes known as nematodes, are small worms that may survive, feed, and breed in the human gut. When the worms enter a host’s body. The host consumes food or drinks water tainted with worms. An insect carrying the worm, such as a mosquito, bites a host and the worm immediately enters the host’s skin. Roundworms can be as little as a millimeter or as long as a meter in length. Infections with roundworm are more common in impoverished, rural communities in warm, tropical regions. Unless there are a significant number of worms present, roundworm infections normally do not create apparent symptoms. The worm can cause disease in the stomach, blood, lymph, or tissues. Gut worms are the most common and may be identified by checking for worms or eggs in feces samples under a microscope. Roundworm infections can be successfully treated with medicine, either as a course of pills or as a powder mixed in water for small newborns. Medications frequently function by interfering with worm movement or metabolism. There are thousands of distinct roundworm species, some of which infect people.

Giant roundworm

Giant roundworms are extremely large (sometimes exceeding 30 centimeters in length) and have a diameter ranging from two to six millimeters. Ascaris lumbricoides is a large roundworm that may grow to be 35 cm long and infect people. Their eggs are deposited in soil in the form of feces and are transferred to people through contaminated food or drink. The eggs hatch in the intestines and make their way to the lungs. They are then coughed up from the lungs into the mouth and swallowed. They make their way to the stomach before making their way to the intestines, where they dwell. Ascaris lumbricoides is most common throughout the world’s tropical and subtropical climates, particularly in communities with inadequate sanitation.


Whipworms get their name from their characteristic whip-like form, which includes a long, thin front end and a thicker tail. The human whipworm is Trichuris trichiura. Whipworms may grow to be five to eight centimeters long.

Trichuris trichiura eggs, like gigantic roundworms, are deposited in the soil in feces and transferred to people by contaminated food or drink. Whipworm’s hatch and mature inside the small intestine before moving to the large intestine as adults. It is estimated that 600-800 million individuals worldwide are afflicted with whipworm. Whipworms live in warm, humid areas, most notably in Asia. Understanding the biology of whipworms might lead to the development of therapeutic therapies for inflammatory disorders including ulcerative colitis and Crohn’s disease. Ulcerative colitis and Crohn’s disease are caused by the body’s own immune system destroying gastrointestinal tissue. In underdeveloped nations, where whipworm infection is frequent, these disorders are uncommon. Scientists believe this is because the worms aid in immune response regulation and prevent the immune system from attacking the gut lining.


Hookworms are either greyish white or pink in color. Their name is derived from the form of their heads, which are somewhat bent in respect to the rest of their bodies, like a hook. ancylostomiasis duodenale has a well-developed mouth with two pairs of teeth, but Necator americanus has a pair of cutting plates that assist them latch on to the intestinal wall rather than teeth. Direct skin contact with contaminated soil, commonly while walking barefoot, is the most prevalent way people become infected with hookworm. People who have been infected may get an itching rash around the place where the worm has pierced the skin. Because hookworms are significantly smaller than huge roundworms, they cause far less tissue damage and blockage. Hookworm infections can cause stomach discomfort, diarrhea, tiredness, and weight loss in severe cases. Hookworms are bloodsucking worms that, in certain situations, can cause enough blood loss to induce anaemia (iron deficiency). Hookworm injury to the gut can impair its capacity to absorb nutrients from meals, resulting in protein deficit and malnutrition. This is especially true for youngsters and pregnant women. Hookworm infection affects about 500 million people worldwide and is the primary cause of maternal and infant morbidity in underdeveloped tropics and subtropics nations.

Filarial worm

filarial roundworms with thread-like filaments Wuchereria bancrofti is spread by mosquito bites and affects around 120 million people worldwide, primarily in Africa, South America, and Asia. resides in lymph nodes It is a leading cause of lymphatic filariasis, a painful and disfiguring condition characterized by swelling and fluid retention in the limbs and genitals. Onchocerca volvulus is carried by the bite of the black Simulism fly and affects about 18 million people globally, with Africa accounting for the bulk of cases. Onchocerciasis is caused by a parasite that dwells in the skin’s fat layer. Because the Simulism fly breeds quickly in fast-flowing water, such as streams and rivers, it is more widely known as river blindness. If the worm enters the eyes, it might result in blindness.


Tapeworms are flat, ribbon-like worms that dwell in their host’s intestines. Cestodes is their scientific name. Humans can become infected with tapeworm by eating uncooked contaminated pork, beef, or seafood, or by ingesting food contaminated with infected animals’ feces. Tapeworms are mainly widespread in poorer nations and are uncommon in the United Kingdom. The tapeworm life cycle comprises at least two hosts; adults reside in one (for example, a human), while larvae dwell in another (for example, a pig). Adult tapeworm infection rarely causes serious symptoms, so people are often unaware they are infected until they notice worm segments in their feces. These segments resemble white rice grains and contain tapeworm’s egg. Infections with tapeworm larvae can be severe if the larvae form cysts within the host’s tissue. Human symptoms vary depending on the type of tapeworm. For example, fish tapeworms take vitamin B12, causing a deficit in the host. A lack of vitamin B12 can cause mouth ulcers, sadness, and a light-yellow hue to the skin.


Trematodes, often known as flukes, are flattened oval or leaf-shaped worms that range in size from a few millimeters to seven or eight centimeters. In Asia, Africa, South America, and the Middle East, infections are the most prevalent. Flukes are divided into two types: tissue flukes and blood flukes. Flukes in the tissues The bile ducts, liver, and other organs are infected by these flukes. The Chinese liver fluke, Clonorchis sinensis, is one example: this fluke dwells in human bile ducts and is assumed to feed on epithelial cells there. Abdominal discomfort, weight loss, and jaundice are all symptoms. These symptoms are caused by enlargement or obstruction of the bile ducts, which are the tubes that transport bile from the liver to the gut.

Blook fluke

Schistosoma is the genus name for all blood flukes. Blood flukes, as the name implies, enter the blood of their host at various phases of their life cycle. Schistosoma parasites cause schistosomiasis (also known as bilharzia), a tropical illness that affects around 240 million people worldwide. People in sub-tropical and tropical areas of the world can become in infected with Schistosoma when playing or bathing in fresh water contaminated with schistosome larvae. Infection symptoms are caused by the body’s immune system responding to parasite eggs. Flu-like symptoms, such as a high fever and muscular pains, are prevalent. A skin rash, cough, and stomach discomfort are other possible symptoms. Chronic infections cause inflammation in parts of the body where eggs have been trapped, such as the bladder, gut, lungs, liver, and even the brain. If left untreated, this might result in long-term organ damage.

Authors: Sadia Ghazanfer1*, Muhammad Sohail Sajid1 Muhammad Zeeshan2, 1Department of Parasitology, University of Agriculture, Faisalabad.One Health Laboratory, Center for Advanced Studies in Agriculture and Food Security (CAS-AFS), University of Agriculture, Faisalabad