MBIO PPT(WORM)

[Virtual Presenter] Helminths, also known as nematodes and trematodes, welcome us to a fascinating world of microscopic organisms. This comprehensive overview explores their characteristics, behaviors, and importance in various ecosystems. Let's begin our journey into the realm of helminths..

[Audio] The group members responsible for this presentation are Marianne Joy, Mark Angelo, Ameer Arielle, Mercado, Francisco, Mendoza, Allena Umandal, Marilou Malacaman, and Joyce Macaraig..

[Audio] Helminths are worm-like parasites that survive through feeding. They need a living host to obtain nutrition and safety, occasionally, this can lead to the host being ill. There are a variety of helminths ranging from the very enormous to the microscopic..

[Audio] The word "helminth" is a general term meaning "worm", but there are many different types of worms. Prefixes are therefore used to designate types: platyhelminths for flat-worms and nemat-helminths for roundworms..

[Audio] Helminths are multicellular eukaryotic invertebrates with either tube-shaped or flattened bodies, exhibiting bilateral symmetry. Parasitic helminths spend most or all of their lives within a host, featuring complex reproductive systems. They typically possess various organ systems, including those responsible for digestion, circulation, nerve function, waste elimination, and reproduction..

[Audio] Helminths, such as nematodes and trematodes, are characterized by their triploblastic nature, meaning they possess three primary layers of tissue: endoderm, mesoderm, and ectoderm. This is distinct from other worms, like flatworms, which lack body cavities, known as acoelomates. Roundworms, on the other hand, have body cavities that are not surrounded by mesoderm, referred to as pseudocoelomates. In contrast, segmented annelids, such as earthworms, have body cavities that are enclosed by mesoderm, making them coelomates..

[Audio] Many helminths are free-living organisms found in both aquatic and terrestrial environments, while others exist as parasites within various animals and even some plants. As parasites, they are a nearly ubiquitous feature among vertebrate animals, with most species hosting worms somewhere..

BIODIVERSITY.

[Audio] There are three main categories of parasitic worms, known as helminths. These include nematodes, such as roundworms, and platyhelminthes, which can be further divided into two subgroups: cestodes, like tapeworms, and trematodes, like flukes..

NEMATODES (ROUND WORM).

[Audio] Nematodes are ecologically ubiquitous and can be both free-living and parasitic on practically any organism. They have basic worm-like bodies, are extremely versatile, and can identify, penetrate, and influence host physiology in parasitic forms. These worms have long thin unsegmented tube-like bodies with anterior mouths and longitudinal digestive tracts. Furthermore, they have a fluid-filled internal body cavity, known as a pseudocoelom, which acts as a hydrostatic skeleton providing rigidity, often referred to as "tubes under pressure"..

[Audio] Nematodes, also known as roundworms, exhibit a unique movement pattern using their longitudinal muscles to create a sideways thrashing motion. This characteristic is distinct from other types of worms. Adult nematodes develop into separate sexes with complex reproductive systems. In addition, they play a crucial role in maintaining ecosystem balance by consuming dead organic matter or microorganisms. However, some parasitic nematodes pose significant economic and health concerns by affecting human and animal well-being, as well as crop productivity..

TREMATODES (FLUKES).

[Audio] Nematodes are round worms with long, thin, unsegmented bodies, anterior mouths, and longitudinal digestive tracts. They have a fluid-filled internal body cavity called pseudocoelum, which acts as a hydrostatic skeleton providing rigidity. Trematodes, also known as flukes, have small, flat, leaf-like bodies with oral and ventral suckers and a blind sac-like gut. Unlike nematodes, they lack a body cavity, being acoelomate, and are dorsoventrally flattened with bilateral symmetry..

[Audio] Helminths, such as nematodes and trematodes, have unique characteristics. Trematodes, also known as flukes, display remarkable movements on surfaces. They achieve this through three-dimensional muscle arrangements. The majority of trematode species possess both male and female reproductive organs, a trait known as hermaphroditism. However, certain blood fluke species develop into distinct male and female adults..

[Audio] Helminths do not multiply inside their hosts unlike viruses, bacteria, protozoa, and fungi. Instead, they grow, mature, reproduce, and their offspring leave the host to infect others. The host's number of worms and infection severity depend on how many infective stages are ingested. This slow development leads to slowly developing, chronic diseases. Although many helminth infections are asymptomatic and well-tolerated, subclinical infections can still cause significant health problems. Furthermore, some helminths cause severe diseases with high rates of illness and death..

LIFE CYCLE.

[Audio] Adult helminths reside within definitive hosts where they reproduce. Larvae, on the other hand, can exist independently or infect intermediate or paratenic hosts, often facilitated by invertebrate vectors. Nematode eggs develop either internally or externally within the host, and after development, the larvae undergo four molting processes before maturing into adult forms..

[Audio] The trematode life cycle involves a complex process of asexual reproduction in snail intermediate hosts. The cycle begins with eggs hatching into free-swimming miracidia, which then infect snails. Within these snails, the miracidia multiply, producing many rediae. These rediae eventually develop into cercariae, which can either directly infect the definitive host or encyst as metacercariae on aquatic plants. When ingested, these metacercariae mature into adult trematodes..

[Audio] Adult fluke lives in the liver of its final host. The life cycle begins when metacercariae are ingested by this host and mature into adult fluke in the liver. Metacercariae develop within cercariae that encyst on grass, forming metacercariae. Hundreds, sometimes thousands, of cercariae leave the intermediate host, a lymnaeid snail, after progressing from miracidia to cercaria inside the snail. Eggs passed in the host's faeces become embryonated in water and hatch, releasing miracidia that invade another aquatic lymnaeid snail..

[Audio] Velkommen til diasnummer 21 ud af 41 i præsentationen om Helminter (nematoder og trematoder), præsenteret af Gruppe 1. I dag vil vi fokusere på helmintheæg, og hvordan de beskytter de udviklende embryoner. Helmintheæg har en beskyttende skal, som sikrer, at embryonerne kan udvikle sig sikkert. Når æggene er modne, frigives larver i værtsdyret eller i miljøet. Disse larver smitter primært nye værter gennem fire ruter: fækal-oral rute, transdermalt, via en mellemvært eller ved predator-byttetransmission. Det er vigtigt at forstå disse smitteveje for at bekæmpe og forebygge infektioner forårsaget af helminter. Som underviser i højere uddannelse er det vores ansvar at videreformidle denne viden til vores studerende, så de er bevidste om risikoen for at blive smittet med disse parasitter. Vi vil fortsætte med at udforske mere om helminter i resten af denne præsentation, så følg med og lær mere om disse parasitter..

ROUTE OF TRANSMISSION.

[Audio] Fecal-oral transmission is a route by which helminths can infect new hosts. This process involves the ingestion of eggs or larvae present in the feces of an infected individual through contaminated food or water. The eggs or larvae then develop inside the new host's body, causing infection. For instance, if an individual consumes Trichuris eggs, it will lead to a gut infection. In contrast, Ascaris eggs and Strongylodes larvae migrate to the lungs before infecting the gut..

[Audio] Helminth larvae can enter the human body through the skin, a process known as transdermal transmission. This occurs when larvae from soil-dwelling helminths, such as geohelminths, penetrate the skin and migrate through the body to the gut. Once in the gut, they mature, reproduce, and produce eggs that are then excreted in feces. A notable example of this type of transmission is hookworm infection, where larvae penetrate the skin, travel through the lungs, and eventually reach the gut, where they feed on blood, leading to anemia in humans..

[Audio] Larval stages of helminths can be taken up by blood-sucking arthropods or undergo amplification in aquatic molluscs, a process known as vector-borne transmission. For instance, Onchocerca microfilariae are ingested by blackflies and then injected into new human hosts. Similarly, Schistosoma eggs release miracidia that infect snails, where they multiply and form cercariae, which are then released to infect new hosts..

[Audio] Predator-prey transmission occurs when encysted larvae within prey animals, whether vertebrate or invertebrate, are consumed by predators. This process allows adult worms to develop and produce eggs. Examples of this type of transmission include Dracunculus larvae in copepods ingested by humans, leading to guinea worm infection; Taenia cysticerci in beef and pork being eaten by humans; and Echinococcus hydatid cysts in offal being eaten by dogs..

[Audio] The nematodes belong to the phylum Nematoda, which is one of the largest groups of animals on Earth. They are characterized by their elongated bodies, usually with a rounded head and a tapering tail. The majority of nematode species are microscopic, but some can grow up to several centimeters in length. Nematodes are found in almost every environment, from soil and freshwater to marine ecosystems and even inside other organisms such as insects and mammals. They play important roles in many ecosystems, serving as both predators and prey for other animals. Some nematodes are also parasitic, infecting plants and animals and causing significant economic losses..

[Audio] Two classes of nematodes are recognized based on the presence or absence of special chemoreceptors called phasmids. These classes are Secernentea, also known as Phasmidea, and Adenophorea, also known as Aphasmidea. Within these classes, there are many different orders recognized. However, when it comes to parasitic infections affecting humans and domestic animals, we mainly see one phasmid order, Trichocephalida, and six phasmid orders, including Oxyurida, Ascaridida, Strongylida, Rhabditida, Camallanida, and Spirurida..

[Audio] The Whipworms, also known as Trichocephalid, have thin, long anterior ends that they embed in the host's intestinal lining. This infection occurs when we ingest their eggs, and the larvae mature into adults within our gut. Unfortunately, this can lead to various symptoms in humans, including inflammation, painful bowel movements, straining, and even rectal prolapse..

[Audio] Female worms of the nematode class called Oxyurida, also known as pinworms, emerge from the anus at night, laying eggs on the surrounding skin. This process causes itching, which leads to hand-to-mouth transmission of the eggs. Enterobius infections often result in irritability and sleep disturbances, particularly in children..

[Audio] In English, the rewritten text would be: The Giant roundworms, also known as Ascarid Roundworms, are easily identified by their three prominent lips. Their life cycle involves a phase where larvae migrate through the lungs after hatching from ingested eggs, before settling in the gut to mature. This process causes digestive upset, protein and nutrient deficiencies, and in severe cases, bowel blockages in humans..

[Audio] Hookworms, also known as Strongyle hookworms, have unique features that enable them to attach themselves to their hosts and feed on their blood. The curved mouthparts of these worms are equipped with cutting plates or teeth that allow them to grasp onto the host's skin and begin feeding. The life cycle of hookworms begins in the soil, where they lay eggs that hatch into larvae. These larvae then penetrate the skin of their hosts, migrating through the lungs before settling in the gut. In cases of heavy infection, hookworms can cause severe iron-deficiency anemia, particularly in children. This condition can lead to serious health complications if left untreated..

[Audio] Threadworms, also known as Rhabditid nematodes, are small worms that live inside the mucus membranes of their hosts. Female threadworms reproduce parthenogenetically, producing eggs that can develop either internally within the host or externally outside the body. This process can lead to the formation of free-living adult worms. In severe cases, heavy infestations of Strongyloides can cause bloody diarrhea in humans..

[Audio] The Guinea worms are large worms that infect human tissue, causing painful blisters on the extremities. These blisters can rupture when submerged in water, releasing larvae that infect copepods. Humans get infected by consuming water containing these infected copepods. Historical records suggest that "fiery serpents" may have described Dracunculus infections..

[Audio] Filarial worms are long, threadlike adults found in the blood vessels or connective tissues of their hosts. Adult females release live larvae, known as microfilariae, that are then picked up by blood-feeding insects such as mosquitoes or flies and transmitted to new hosts. These infections can cause various health problems, including nodules, skin damage, and even blindness. In some cases, they can also lead to conditions like elephantiasis..

[Audio] The Trematodes, also known as flukes, are a group of parasitic flatworms that belong to the phylum Platyhelminthes. They are characterized by their flat, leaf-like bodies and their ability to attach themselves to the digestive systems of animals and humans. The Trematodes are further divided into several subgroups, including the Digenea, Monogenea, and Aspidogastrea. These subgroups differ from one another based on their body shape, size, and the type of host they infect. The Trematodes are found worldwide, and they can cause significant disease and discomfort in infected individuals..

[Audio] The two major groups of trematodes recognized based on their structure and development are the monogenean trematodes and the digenean trematodes. Monogenean trematodes are characterized by complex posterior adhesive organs and direct life cycles involving larvae called oncomiracidia. They are primarily ectoparasites of fish. On the other hand, digeneans are internal parasites of various vertebrates, utilizing snails as intermediate hosts..

[Audio] Digenean trematodes have oral and posterior suckers, and they exhibit a heteroxenous life-cycle. Adult worms infect vertebrates, while larval miracidia infect molluscs. The larvae then multiply and produce free-swimming cercariae. There are ten digenean orders recognized based on their morphological and biological differences, and two of these orders are particularly significant from a medical and veterinary perspective..

[Audio] The liver flukes, also known as echinostomatid fascioids, live as adults in the hepatic bile ducts of mammals, causing fibrotic 'pipestem' disease. These parasites multiply in freshwater snails, and mammals become infected by consuming metacercariae attached to aquatic vegetation. Several species of Fasciola cause hepatic disease in domestic ruminants and occasionally in humans..

[Audio] Adult Schistosoma worms are distinct from other blood flukes because they do not possess both male and female reproductive organs. Instead, they comprise separate sexes that coexist in the mesenteric veins of mammals. Female worms release eggs that can actively penetrate tissues to be excreted in urine or feces, or they become trapped in organs, resulting in granuloma formation. The released miracidia infect aquatic snails, where they develop into fork-tailed cercariae that penetrate the skin of their hosts. Several Schistosoma species are responsible for causing schistosomiasis or bilharzia in humans..

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