Parasitism: Definition, Meaning, Types, Examples, Advantages

Parasitism definition: Parasitism is a type of ecological relationship where one organism, the parasite, lives on or inside another organism, the host, and benefits at the host's expense. Parasites depend on their hosts for nutrients and shelter, often causing harm or disease to the host without providing any benefit in return. This interaction can be found across many species, from tiny bacteria to larger organisms like tapeworms. This article covers the definition of parasitism, types, examples, parasitic food chain, human parasitic diseases, and control methods of parasitism. The chapter Organism and Populations in Biology discusses parasitism

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This Story also Contains

1. What is Parasitism?
2. Types of Parasitism
3. Parasitic Food Chain
4. Human Parasitic Diseases
5. Recommended Video on Parasitism

What is Parasitism?

Essentially, parasitism is a kind of symbiosis where one organism or organism’s part uses another organism, host, for his or their benefit, often existing on the host’s tissues or obtaining food from him. This interaction varies from being relatively innocuous to pathogenic and effectively may adversely affect the host’s physiology and her reproductive potential. To summarize, thus the study of parasitism is important for comprehending its effects on population health, and agriculture.

In the case of parasites, they can affect the social structure and demography of a population or even cause shifts in its behavioural patterns besides acting as agents of natural selection for the hosts. Also, they present formidable difficulties in medicine and veterinary sciences owing to their capacity to infiltrate beyond the immune system and adapt to drug therapies. Studying parasitic interactions expands our understanding of the co-evolutionary dynamics and helps in the designing of measures for disease management in various ecosystems.

Types of Parasitism

The types of parasitism are described below-

Ectoparasitism

Ectoparasitism is defined as a type of parasitism where the parasite dwells on the outer skin of the host and feeds on the host's blood and/or tissues. Some of the examples of vectors are lice, ticks, and fleas. These parasites usually have a strong hold on the skin or feathers of the host and are potential disease vectors.

Endoparasitism

Endoparasitic means a parasite spends part of or the entirety of its life cycle, inside the host’s body. For instance, members include tapeworms that are found in the intestines and protozoa such as Giardia that infect the gut. Endoparasites are parasites which may live in the internal body organs of a host and part of their life cycle, may involve a change of hosts.

Brood Parasitism

To start with, brood parasitism is a kind of non-pairwise mutualism by which one species provides parental care for the young of another species as the latter lays eggs in the provider’s nest. Some such as cuckoos and cowbirds are known to lay eggs in the nests of other birds and then the hosts are brainwashed into taking care of the foreign eggs.

Social Parasitism

Social parasitism usually encompasses parasites that depend on the social behaviours of other species; especially insects such as ants and bees. Examples are parasitic ants that take over the host colony by manipulating it to act as workers for the ants’ young ones.

Also Read-

• MCQ on Parasitism
• Organism and Population
• Biotic Factors
• Abiotic Factors

Parasitic Food Chain

The energy in a parasitic food chain is transferred through parasitic relationships. Thus the traditional food chains, which include herbivores and carnivores as well as decomposers, are distinct from the parasitic food chains; hence parasites include hosts and often hyperparasites, as well (parasites living on other parasites).

Structure of a Parasitic Food Chain:
Primary Producer: In a general sense, the food chain begins with plants or autotrophs, which produce energy through photosynthesis.
Primary Consumer (Host): The herbivore or some other consumer feeds on the plant while storing energy in the tissues. The organism is a host to a parasite.
Parasites: These organisms include the likes of tapeworms, ticks, or protozoa, which feed on the host organism for nutrition. Energy is usually drawn directly from the body of the host organism.
Hyperparasites: Some parasitic food webs are hyperparasites; which means it's a parasite on a parasite. That is, it's a parasite living on another parasite. Bacteria could be infecting ticks, or fungi growing on parasitic insects.

Human Parasitic Diseases

The diseases caused by human parasites are discussed below-

Overview of Common Human Parasitic Diseases

Malaria

• Symptoms: Malaise, fever, chills, inflammatory disorders, anaemia, and renal failure in the severe forms.

• Causes: Protozoan parasites belonging to the genus, Plasmodium which are transmitted through the bite of infected female Anopheles mosquitoes.

• Treatment: Prescribed drugs include chloroquine, artemisinin-based combination therapies (ACTs), and any other drugs depending on the local malaria-drug resistance.

Schistosomiasis

• Symptoms: He has experienced abdominal pain, diarrhoea, blood in urine or stool depending on the contemporary health status, and liver and spleen enlargement in chronic cases.

• Causes: The examples of parasites that cause this include Trematode, flavorms, also known as blood flukes sourced through contact with water containing the SSDs.

• Treatment: However, the main treatment for the illness is through the administration of mebendazole and praziquantel which aims at killing the adult worms.

Leishmaniasis

• Symptoms: Ulcero-nodular skin lesions (cutaneous), high fever, marked weight loss, toxicity which may involve an organ in the body (visceral).

• Causes: Protozoans of the kind Leishmania conveyed through infected sandfly vectors.

• Treatment: Antiparasitic drugs like antimonials miltefosine, amphotericin B and other drugs depending on the type of disease and its intensiveness.

Prevention and Control Measures

Vector Control: Insecticide-treated bed nets and walls and ceilings with insecticide sprays to ensure that no malaria-causing mosquito lays eggs in the room.

Sanitation: Getting close to water source and proper sanitation such as irrigation of water and working for improved drains to eradicate schistosomiasis.

Personal Protection: Protective clothing and insect repellents to avoid contact with sandflies in a leishmaniasis-endemic zone.

Treatment Programs: Prescription of drugs to communities, monitoring, and treatment to control the spread of the diseases and contain the epidemics.

Also Read-

Recommended Video on Parasitism