Haseeb Ullah

Platyhelminthes Definition Platyhelminthes (Flatworms)   Characteristics: Flattened, bilaterally symmetrical bodies.   Group: Includes both freeliving and parasitic species.   Medical Importance: Parasitic flatworms include classes like Trematoda (flukes) and Cestoda (tapeworms). Lifecycle in Humans Trematodes (Flukes) 1 . Eggs: Released in human feces or urine. 2. Larval Stages: Eggs hatch into miracidia, infecting intermediate hosts (usually snails). 3. Cercariae: Develop within snails, released into water. 4. Human Infection: Penetrate human skin or ingested. 5. Adult Stage : Migrate to organs (e.g., liver, lungs), mature into adult flukes. 6. Reproduction: Adults lay eggs, excreted from human body. Example: Schistosoma spp. Lifecycle 1. Eggs: Excreted in feces. 2. Miracidia: Hatch and infect snails. 3. Cercariae: Released from snails, penetrate human skin. 4. Schistosomula: Migrate through the bloodstream to the liver. 5. Adults:

  Definition Platyhelminthes, commonly known as flatworms, are a phylum of invertebrates that are characterized by their flattened, bilaterally symmetrical bodies. This group includes both freeliving and parasitic species. The parasitic flatworms are of significant medical importance and include classes such as Trematoda (flukes) and Cestoda (tapeworms).   Lifecycle in Humans The lifecycle of parasitic platyhelminths varies depending on the species. Here are the general lifecycles for common humaninfecting flatworms:   Trematodes (Flukes) 1. Eggs: Eggs are released into the environment through human feces or urine. 2. Larval Stages: Eggs hatch into miracidia, which infect specific intermediate hosts (usually snails). 3. Cercariae: Within the snail, the miracidia develop into cercariae, which are released into the water. 4. Human Infection: Cercariae penetrate human skin or are ingested, depending on the species. 5. Adult Stage: Cercariae migrate to specific organ