Parasites Causing Human Diseases

Parasites Causing Human Diseases: A parasite is a creature that lives on or in its host and feeds on or at the expense of that host. Protists, bacteria, viruses, fungus, plants, and mammals are all examples of parasites. Parasites are thought to make up 40% of all animal species. Some parasites (ectoparasites) dwell on their hosts, while others (endoparasites) reside inside them.

Overview

In most cases, parasites enter the body through the mouth or the skin. Doctors diagnose infection by analyzing or sending samples of blood, stool, urine, sputum, or other contaminated tissue to a laboratory for investigation.

Features

In most cases, parasites are smaller than their hosts.

Invertebrates and vertebrates are both hosts for parasites.

Adult parasites can reside on the host (like lice), in the host (like tapeworms), or feed on the host regularly (e.g. mosquitoes).

Parasites do not usually kill their hosts, although they can harm them indirectly by transmitting infections. This could impact the host’s behaviour, metabolism, or reproductive ability.

Many parasites use hooks, claws, or suckers to adhere to their host.

For feeding, parasites usually have sucker mouthparts (like leeches) or piercing and sucking mouthparts (like fleas).

Adults and children can both be parasitic. The young are parasites in some circumstances, while the adult is not.

Parasites range in size from microscopic one-celled organisms known as protozoa to large worms visible to the human eye. In the United States, parasite diseases can be found. Giardia infections can be spread via contaminated water. Toxoplasmosis, which is harmful to pregnant women, can be transmitted by cats. Others, like malaria, are widespread in other parts of the globe.

Parasites are classified into three categories.

• Protozoa– Protozoa are minute, one-celled organisms that can live free or as parasites. They can replicate in humans, which helps them survive while also allowing dangerous diseases to spread from a single organism. Protozoa that dwell in a human’s intestine are often transmitted to another human via a faecal-oral pathway (for example, contaminated food or water or person-to-person contact). Human blood or tissue-dwelling protozoa are spread to other humans through an arthropod vector.

Examples- Amoeba, Euglena, and paramecium

• Helminthes- Helminths are enormous, multicellular organisms that may be seen with the naked eye when they reach adulthood. Helminths, like protozoa, can be either free-living or parasitic. Helminths cannot reproduce in humans in their adult state. In humans, there are three types of helminths.

Examples- Tapeworm, Fleas, and Roundworms

• Ectoparasites- Blood-sucking arthropods like mosquitoes are ectoparasites (since they rely on a blood meal from a human host for existence); the term is mostly used to refer to organisms like ticks, fleas, lice, and mites that adhere or burrow into the skin and stay there for lengthy periods (e.g., weeks to months). Arthropods are significant in producing diseases in and of themselves. Still, they are far more important as vectors, or transmitters, of various infections that inflict tremendous morbidity and mortality because of the diseases they spread.

Examples- Louse, cat flea, and crab louse

Parasitic individuals can be found in many invertebrate groups. Fleas, ticks, parasitic mites, leeches, worms (e.g. roundworms), and parasitic flies are well-known parasites (e.g. mosquitoes). Stylos are wasps, bees, and insect parasites. The female looks like a larval and spends its whole life cycle inside the host. The winged, free-living males use scent to find females and mate with the little piece of the female that protrudes from the host.

Symbiosis is a natural phenomenon when two individuals of different species live near one another.

Infections caused by parasites

In the tropics and subtropics, as well as in more temperate climes, parasitic infections impose a huge burden of disease. Malaria is the parasite disease that kills the most people worldwide. Malaria claims the lives of about 400,000 people each year.

Parasitic disorders such as lymphatic filariasis, onchocerciasis, and Guinea worm disease are among the Neglected Tropical Diseases which have received little attention from the public health community. NTDs afflict around 1 billion people worldwide, primarily in low-income nations’ rural areas. These diseases significantly impact endemic populations, including the decreased capacity to attend school or work, stunted growth in children, impairment of cognitive skills and development in early childhood, and a significant economic burden on entire countries.

Parasitic illnesses have different symptoms depending on the parasite. Listed below are a few examples:

Diarrhoea, abdominal cramping and bloating, gas, nausea, exhaustion, and weight loss are all signs of a Giardia infection (giardiasis). However, not everyone with the virus exhibits symptoms, and they may inadvertently spread the infection to others.

Tapeworm: Tapeworm symptoms may not appear for up to 8 weeks after the tapeworms have established themselves in the bowel. Nausea, diarrhoea, constipation, and abdominal pain are some of the minor and non-specific symptoms. Tapeworms that go untreated can survive for years and cause malnutrition. Headaches, blindness, and convulsions are all possible long-term side effects.

Chagas illness: Most patients do not show any symptoms for the first several weeks or months after contracting Chagas disease. Mild swelling at the injection site, low fever, body aches and pains, skin rash, headache, nausea and vomiting, diarrhoea, and swollen glands are some of the symptoms they may encounter if they do. After that, the infection progresses to the chronic stage. This is when signs and symptoms may appear for individuals who did not have any during the acute period. An erratic heartbeat, congestive heart failure, an enlarged oesophagus that makes swallowing difficult, and abdominal pain or constipation are all possible symptoms. The virus could also cause a heart arrest.

Prevention of parasites

Wear gloves when working with animals or in areas where animal excrement may be present, such as gardens, and wash your hands thoroughly afterwards.

Drink exclusively from sealed bottles when travelling or in a region where food or water may be polluted. Avoid using ice cubes in your drinks since they may not have been manufactured with pure water. Also, eat only things that have been completely cooked. Fruit that has been washed with clean water and has peels may be okay to consume.

FAQ’s

What are parasites?

A parasite is a creature that lives on or in its host and feeds on or at the expense of that host.

Where are parasites found?

Parasitic individuals can be found in many invertebrate groups. Fleas, ticks, parasitic mites, leeches, worms and parasitic flies are some well-known parasites.

What are the infections caused by parasites?

Infections caused by parasites are diarrhoea, abdominal cramping and bloating gas, nausea, exhaustion, and weight loss.

Q. Mention the classification of parasites

Ans. Parasites are classified into three categories

• Protozoa
• Helminthes
• Ectoparasites