Parasitology Nutrition-2 2 PDF

The Cestodes Multi-cellular worms having flat appearance. 20  Taenia species There are two members of the Taenia species that are of clinical significance to humans, Taenia solium and Taenia saginata They are similar! T...

The Cestodes Multi-cellular worms having flat appearance. 20  Taenia species There are two members of the Taenia species that are of clinical significance to humans, Taenia solium and Taenia saginata They are similar! Taenia saginata: – Common name: Beef tapeworm (intermediate host) – Disease names: Taeniasis, beef tapeworm infection Taenia solium: – Common name: Pork tapeworm (intermediate host) – Disease names: Taeniasis, pork tapeworm infection. 21  Taenia species MORPHOLOGY – Egg: – The eggs of T. solium and T. saginata are indistinguishable! Eggs appears roundish Consists of a hexacanth embryo, including three pairs of hooklets The embryo is surrounded by a yellow-brown shell (known as an embryophore). 22  Taenia species MORPHOLOGY – Scolices (heads): single is scolex Primary difference between T. saginata and T. solium: – T. solium contains a rostellum and hooks – T. saginata lacks these structures – Both contain 4 suckers – Proglottids: Taenia spp are hermaphrodite, having both male and female organs. 23  A, Taenia solium scolex. B, Taenia solium A, Taenia saginata scolex. scolex, 40×. 24 25 26  Taenia species Life Cycle – Infection with Taenia spp. occurs following the ingestion of raw or undercooked beef (T. saginata) or pork (T. solium) contaminated with a cysticercus larva Cysticercus larva? – The infective stage – Consists of an inverted scolex surrounded by a bladder-like cyst that is filled with fluid. 27  Taenia species Life Cycle – The larva releases in the small intestine – Scolex attaches to the intestinal mucosa and mature into an adult worm – The adult worm multiplies, producing numerous eggs, some of which may be passed into the feces These eggs are consumed by animals (cow or pig) in which the eggs hatches The larva migrates via the blood to the animal tissue and converts into the infective cysticercus larval stage A new cycle is initiated as human ingest infected animal meat. 28 29  Taenia species Clinical Symptoms Asymptomatic: – Most people who become infected with Taenia spp. typically remain asymptomatic Taeniasis (Beef or Pork Tapeworm Infection): – Diarrhea, abdominal pain and weight loss – Vomiting, and nausea may also develop. 30  Taenia species Nutrient Malabsorption and Deficiency Competition for Nutrients, leading to reduced availability of essential nutrients (e.g., CHO, proteins, and fats) Micronutrient Deficiency: Vitamin B12 deficiency, Iron deficiency anemia, leading to fatigue, anemia, and neurological issues Diarrhea and appetite loss contribute to nutrient losses Weight loss due to the parasite consuming nutrients Impact on Child Development Chronic infections in children can impair growth, cognitive development, and school performance. 31 Nematodes (Roundworm) 32  1) Ascaris lumbricoides – Life cycle Only one host, human (No intermediate host !) Transmission: Fecal-oral Infective stages: Embryonated egg Ingested> stomach> Small intestine mucosa> circulation> lung> trachea> pharynx> swallow> S. intestine. 33 1) Ascaris lumbricoides - Morphology 1) Eggs: Fertilized Eggs: rounded to oval (more rounded) Are laid by females after inseminated by mating with a male These are embryonated and develop into the infective eggs Unfertilized Eggs: rounded to oval (more oval) In the absence of a male worm, the female produces unfertilized egg Are laid by uninseminated female These are non-embryonated and cannot become infective. 34 1) Ascaris lumbricoides - Morphology Fertilized Eggs Unfertilized Eggs 35 1) Ascaris lumbricoides - Morphology 2) Adult worms: - Cylindrical - Female Worm: - Longer, tail is straight - Possess vulva at the body side (vulvar waist) Male Worm: The posterior end is curved to form a hook and forms a pair of copulatory spicules of equal size. 36 1) Ascaris lumbricoides - Morphology 37  1) Ascaris lumbricoides – Pathogenicity Cause a disease known as scariasis Caused by both adult worms and migrating larvae 1. Pathogenicity of adult worm: Severe malnutrition Night blindness (due to malabsorption of ‘’Vit.A deficiency’’) Long-term malnutrition can lead to growth retardation Intestinal obstruction (heavy infection). 38 1) Ascaris lumbricoides – Pathogenicity 2- Pathogenicity of larvae: – Loeffler’s syndrome? Inflammation, hypersensitivity, irritation, and wheezing reaction in lungs due to larval migration. 39