Helminthology Terminologies Quiz

Types of Transmission

• Active Transmission: occurs through penetration
• Inoculative Transmission: occurs when infective stage of the parasite has developed in the body of an arthropod
• Passive Transmission: occurs through contaminations

Effects of Parasite on Individual Host

• Injurious/Defensive: wide range of severity, leading to manifested disease often resulting to death
• Mechanical Injury: involves destructive action such as perforation of an organ, destruction of cells, piercing tissues, obstruction of a lumen
• Chemical Injury: results from secretions by the parasites, introducing pathogenic organisms such as bacteria

Phylum Platyhelminthes (Flatworms)

• Characteristics: soft-bodied, flatworms, incomplete digestive tract in trematodes, none at all in cestodes
• Reproduction: usually hermaphroditic, bisexual, with male and female reproductive organs present in one individual
• Organs: embedded in tissues called parenchyma
• Excretory organs: called flame cells or solenocytes

Classes of Platyhelminthes

• Turbellaria (Eddy Worms, Planarians): non-parasitic, living in fresh water
• Trematoda (Flukes): monozoic, single body, alimentary canal is present, parasitic
• Cestoda (Tapeworms): polyzoic, segmented body, alimentary canal is absent, parasitic

Phylum Nemathelminthes (Roundworms)

• Characteristics: sexes are separate, alimentary canal is present, perienteric space is present, parenchyma is absent
• Excretory organs: consisting of lateral canals along the body wall, flame cells are absent
• Life cycle: may be direct or indirect

Phylum Acanthocephala (Thorny Headed Worms)

• Characteristics: cylindrical, thick cuticula, retractile proboscis with spines
• Life cycle: indirect
• Reproduction: separate sexes, parasitic

Trematodes (Liver Flukes)

• Fasciolopsis: acute or chronic disease
• Acute disease: associated with large number of migrating larvae, resulting in sudden death due to acute and massive hemorrhage
• Chronic disease: characterized by anemia, hypoalbuminaemia, weight loss, begins when immature larvae reach the bile ducts, mature into adult flukes, and start producing eggs

Helminthology Terminologies

• Monoecious (Hermaphrodite): male and female sexual organs in one individual
• Dioecious: male and female sexual organs are in separate individuals
• Host: animal which is parasitized
• Final or Definitive Host: animal in which the reproducing stage (adult) of the parasite occurs
• Primary or Prime Host: animal in which parasite is commonly found and development occurs
• Transport Host: carries part of the immature stage of the parasite but no development occurs
• Paratenic Host: harbors a larval stage of the parasite but cannot get rid of it, and further development of the parasite depends upon ingestion of the paratenic host by the final host
• Reservoir Host: an animal from which infection may be passed to other species, in veterinary usually from wild to domesticated stock
• Intermediate Host: one in which part of the immature phase of the life cycle is spent and development occurs
• Prepatent Period: the time which elapses between the entry of the infective stage up to the demonstration of adult parasites within the host
• Erratic/Aberrant Parasite: wander into unusual places in the normal host
• Incidental Parasite: those which occasionally appear in unusual host