Nematodes are roundworms that include many parasitic worms that infect humans. They exhibit a range of life cycles and morphologies. Many nematodes have both free-living and parasitic stages. They infect humans through ingestion or skin penetration of eggs or larvae. Common symptoms include diarrhea, abdominal pain, and anemia. Diseases are diagnosed through identification of eggs or larvae in stool samples.
The document provides background information on helminths (parasitic worms). It discusses their lifecycles, transmission methods, locations within the host body, and impacts on human health. Specifically, it covers the major groups of intestinal nematodes (roundworms) that commonly infect humans, including their classification, lifecycles involving egg/larval stages and environmental transmission, clinical symptoms, and methods of diagnosis through fecal sample examination.
This document discusses several intestinal nematodes (roundworms) that can infect humans. It provides details on the morphology, life cycles, modes of transmission, symptoms, and diagnosis of Ascaris lumbricoides (the large roundworm), the two hookworm species (Ancylostoma duodenale and Necator americanus), Strongyloides stercoralis, Enterobius vermicularis (the pinworm), and Trichuris trichiura (the whipworm). Each worm has a unique life cycle involving eggs, larvae, and adult stages, and they are transmitted through ingestion of contaminated food, water, or soil. Symptoms vary but often involve abdominal pain, diarrhea, and
This document discusses several nematode parasites that infect humans. It begins by providing background on the phylum Nematoda and describes the life cycle as including egg, larval and adult stages. It then classifies nematode parasites into those that infect the small intestine (Aphasmidia and Phasmidia classes) and those that infect the large intestine (Phasmidia class). Several key nematode species are described in detail, including Ascaris lumbricoides, Trichuris trichiura, hookworms (Necator americanus and Ancylostoma duodenale), Strongyloides stercoralis and Capillaria philippinensis. For each species, the
The document provides information about helminths (parasitic worms). It begins by defining helminths and outlining the learning objectives and classification of helminths. The document then focuses on intestinal nematodes (roundworms), describing their key features, life cycles, transmission routes, and important examples like Ascaris lumbricoides and Trichuris trichiura. It discusses the morphology, epidemiology, pathogenesis, laboratory diagnosis and treatment of these common helminth infections.
Nematodes are roundworms that can infect humans. They are divided into three groups based on where they reside in the body: intestinal nematodes, intestinal-tissue nematodes, and blood-tissue nematodes. Some common intestinal nematodes discussed in the document include Ascaris lumbricoides (the large roundworm), Enterobius vermicularis (pinworm), Trichuris trichiura (whipworm), Ancylostoma duodenale and Necator americanus (hookworms), and Strongyloides stercoralis (threadworm). Their life cycles, epidemiology, clinical manifestations, diagnosis, treatment and prevention are described.
Nematodes are roundworms that can infect humans. They are divided into three groups based on their location in the body: intestinal nematodes, intestinal-tissue nematodes, and blood-tissue nematodes. Some common intestinal nematodes discussed in the document include Ascaris lumbricoides (the large roundworm), Enterobius vermicularis (pinworm), Trichuris trichiura (whipworm), Ancylostoma duodenale and Necator americanus (hookworms), and Strongyloides stercoralis (threadworm). These parasites have complex life cycles involving eggs, larvae, and adult worms that can cause diseases like ascariasis and hookworm infection
Necator americanus is a parasitic nematode known as the New World hookworm that infects humans. It lives in the small intestine and is a leading cause of iron-deficiency anemia in children in developing countries. The infective larvae penetrate the skin, travel to the lungs and intestines, and mature into adults that attach to the intestinal wall and suck blood, causing symptoms like abdominal pain and diarrhea. Eggs are passed in feces and can develop into infective larvae that can survive for weeks in soil, continuing the life cycle.
The document provides background information on helminths (parasitic worms). It discusses their lifecycles, transmission methods, locations within the host body, and impacts on human health. Specifically, it covers the major groups of intestinal nematodes (roundworms) that commonly infect humans, including their classification, lifecycles involving egg/larval stages and environmental transmission, clinical symptoms, and methods of diagnosis through fecal sample examination.
This document discusses several intestinal nematodes (roundworms) that can infect humans. It provides details on the morphology, life cycles, modes of transmission, symptoms, and diagnosis of Ascaris lumbricoides (the large roundworm), the two hookworm species (Ancylostoma duodenale and Necator americanus), Strongyloides stercoralis, Enterobius vermicularis (the pinworm), and Trichuris trichiura (the whipworm). Each worm has a unique life cycle involving eggs, larvae, and adult stages, and they are transmitted through ingestion of contaminated food, water, or soil. Symptoms vary but often involve abdominal pain, diarrhea, and
This document discusses several nematode parasites that infect humans. It begins by providing background on the phylum Nematoda and describes the life cycle as including egg, larval and adult stages. It then classifies nematode parasites into those that infect the small intestine (Aphasmidia and Phasmidia classes) and those that infect the large intestine (Phasmidia class). Several key nematode species are described in detail, including Ascaris lumbricoides, Trichuris trichiura, hookworms (Necator americanus and Ancylostoma duodenale), Strongyloides stercoralis and Capillaria philippinensis. For each species, the
The document provides information about helminths (parasitic worms). It begins by defining helminths and outlining the learning objectives and classification of helminths. The document then focuses on intestinal nematodes (roundworms), describing their key features, life cycles, transmission routes, and important examples like Ascaris lumbricoides and Trichuris trichiura. It discusses the morphology, epidemiology, pathogenesis, laboratory diagnosis and treatment of these common helminth infections.
Nematodes are roundworms that can infect humans. They are divided into three groups based on where they reside in the body: intestinal nematodes, intestinal-tissue nematodes, and blood-tissue nematodes. Some common intestinal nematodes discussed in the document include Ascaris lumbricoides (the large roundworm), Enterobius vermicularis (pinworm), Trichuris trichiura (whipworm), Ancylostoma duodenale and Necator americanus (hookworms), and Strongyloides stercoralis (threadworm). Their life cycles, epidemiology, clinical manifestations, diagnosis, treatment and prevention are described.
Nematodes are roundworms that can infect humans. They are divided into three groups based on their location in the body: intestinal nematodes, intestinal-tissue nematodes, and blood-tissue nematodes. Some common intestinal nematodes discussed in the document include Ascaris lumbricoides (the large roundworm), Enterobius vermicularis (pinworm), Trichuris trichiura (whipworm), Ancylostoma duodenale and Necator americanus (hookworms), and Strongyloides stercoralis (threadworm). These parasites have complex life cycles involving eggs, larvae, and adult worms that can cause diseases like ascariasis and hookworm infection
Necator americanus is a parasitic nematode known as the New World hookworm that infects humans. It lives in the small intestine and is a leading cause of iron-deficiency anemia in children in developing countries. The infective larvae penetrate the skin, travel to the lungs and intestines, and mature into adults that attach to the intestinal wall and suck blood, causing symptoms like abdominal pain and diarrhea. Eggs are passed in feces and can develop into infective larvae that can survive for weeks in soil, continuing the life cycle.
This document describes ascariasis, caused by the roundworm Ascaris lumbricoides. It is most common in children in tropical areas with poor sanitation. The worms live in the small intestine and the female can lay up to 200,000 eggs daily that are passed in feces. When eggs are ingested, they hatch in the intestines releasing larvae that migrate through organs before maturing in the lungs and being swallowed to the intestines. Heavy infections can cause malnutrition, obstruction, and other complications. Diagnosis involves finding eggs in stool or worms. Treatment includes mebendazole or pyrantel pamoate. Prevention relies on proper sanitation and hygiene.
Nematodes are roundworms that range in length from 90 μm to 1000 mm. They have an anterior mouth and posterior anus. Their life cycle involves hatching from eggs as larvae and molting through different larval stages to become adults. Pinworm (Enterobius vermicularis) is a common intestinal nematode. Females are 10mm long while males are 3mm. It has a direct life cycle. Pinworm infection is widespread, with over 1 billion cases globally. The parasite's eggs are deposited on the skin at night and spread through contaminated surfaces. Common symptoms include irritation and itching. Diagnosis involves examining adhesive tape touched to the skin under a microscope for eggs. Treatment and prevention
This document discusses Ascaris lumbricoides, the roundworm. It describes the morphology of the adult worms and eggs. The lifecycle is completed within a single human host. Symptoms of infection can include intestinal or pulmonary disease. Diagnosis is made by identifying eggs in stool samples. Treatment involves anthelmintic drugs. Prevention focuses on proper sanitation and hygiene.
This document provides information about protozoa. It begins by defining protozoa as eukaryotic, unicellular organisms that lack cell walls and use cilia, flagella, or pseudopodia for motility. There are around 20,000 protozoan species, most of which are free-living in water or soil. Some can be parasitic or symbiotic. Important medically relevant protozoa include Entamoeba histolytica and Giardia lamblia, which can cause intestinal infections. Other protozoan diseases mentioned are African sleeping sickness caused by Trypanosoma brucei and Chagas disease caused by Trypanosoma cruzi. The document also briefly discusses helmin
This document discusses several intestinal nematodes including Ascaris lumbricoides (roundworm), Trichuris trichiura (whipworm), Enterobius vermicularis (pinworm), and hookworms. It provides details on the morphology, life cycles, pathogenesis, clinical features, diagnosis, treatment and prevention of these parasites. Intestinal nematodes can cause symptoms ranging from mild to severe depending on the worm burden. Diseases result from nutrient deficiency, intestinal obstruction, or blood loss caused by hookworms. Sanitation and hygiene practices like handwashing and use of toilets are important for prevention.
Hookworms are intestinal parasitic roundworms that infect the small intestine. They have a direct lifecycle where the infective third stage larva penetrates the skin and migrates through the lungs before reaching the small intestine to mature and reproduce. Eggs are passed in feces. Pathogenesis is due to the host immune response to migrating larvae, mechanical damage from larval migration, effects of adult worms in the intestines including blood loss. Common symptoms include iron deficiency anemia.
Ascaris lumbricoides, also known as the giant intestinal roundworm, is a parasitic nematode that infects the small intestine of humans. It has a worldwide distribution, especially in tropical and subtropical areas with poor sanitation. The adult worms can reach lengths of 20-35 cm in females and 15-30 cm in males. The life cycle involves fertilized eggs passing in feces and developing into infective larvae outside the body. People become infected by ingesting these embryonated eggs. The larvae hatch in the intestine, penetrate the intestinal wall, migrate through the lungs, are swallowed and pass into the intestine where they mature into adult worms. Most infections are asymptomatic, but symptoms can include abdominal pain,
Ascaris lumbricoides is a common roundworm parasite that infects an estimated 1 billion people worldwide (1 out of 4 people), being most prevalent in underdeveloped areas with poor sanitation. It is transmitted via ingestion of eggs from contaminated food or soil and causes symptoms ranging from abdominal discomfort to pulmonary issues during larval migration. Treatment involves anthelmintic drugs like mebendazole or albendazole and prevention focuses on improved sanitation and limiting the use of human feces as fertilizer.
1. The document describes the life cycles of several parasitic roundworms (nematodes) that infect humans, including Ascaris lumbricoides, Enterobius vermicularis, Trichuris trichiura, Ancylostoma duodenale, Strongyloides stercoralis, and Trichinella spiralis.
2. It provides details on the morphology, life stages, transmission, localization in the host, and clinical manifestations of each parasite.
3. The life cycles generally involve eggs passing in feces and developing into infective larvae in the soil, which then penetrate the skin or are ingested to develop into adult worms that reproduce sexually and release eggs to complete the
This document summarizes several types of parasitic helminths (worms) that can infect humans. It describes the life cycles, geographical distribution, clinical presentation, diagnosis, and treatment of important nematode infections including hookworms, Strongyloides, ascariasis, enterobiasis, trichuriasis, and filariasis. Key points are that these soil-transmitted helminths typically have complex life cycles involving larval stages in soil that infect via skin penetration or ingestion, causing anaemia, pulmonary symptoms, or intestinal obstruction in heavy infections. Diagnosis involves finding eggs or larvae in stool or tissue samples, and treatment consists of anthelmintic medications like albendazole or me
This document provides information on the taxonomy, morphology, life cycles, pathogenesis, clinical features, diagnosis, and treatment of various helminth parasites. It describes the characteristics of nematodes and discusses specific nematodes like Trichuris trichura and Enterobius vermicularis. For T. trichura, it provides details on its morphology, life cycle, clinical manifestations including rectal prolapse, and microscopic identification of eggs in stool samples. For E. vermicularis, it discusses epidemiology in children, morphology of adult worms and eggs, life cycle involving nocturnal emergence of females, and diagnosis using scotch tape tests. Treatment involves repeated doses of albendazole or mebendazole
Enterobius vermicularis, commonly known as pinworm or seat worm, is a parasitic nematode that infects the human intestine. It has a two month lifecycle where sexually mature worms inhabit the small and large intestines and lay eggs in the perianal area. Infection occurs when eggs are ingested and hatch in the small intestine. Pinworms are a common cause of itching and irritation around the anus but often cause no symptoms. Diagnosis involves detecting eggs on perianal skin or microscopic examination of stool samples. Treatment involves administering anthelmintic drugs to infected individuals and members of their household. Prevention focuses on good personal hygiene like handwashing and cutting fingernails short
1. Ascaris lumbricoides, or the roundworm, is one of the most common intestinal nematodes infecting humans. It inhabits the small intestine and can reach lengths of over 20 cm in females.
2. The life cycle involves ingestion of infective eggs from contaminated food, water, or soil. Inside the intestine, the larvae hatch and mature into adults. Females produce thousands of eggs daily that are passed in feces.
3. Symptoms range from mild to severe and include abdominal pain, nausea, intestinal obstruction, or migration of larvae to other organs causing pneumonia. Complications can also include appendicitis or pancreatitis. Diagnosis is made by finding eggs in
The document discusses several species of nematodes (roundworms) that can infect humans, including their morphology, life cycles, and epidemiology. It focuses on two specific species: Ascaris lumbricoides (the large intestinal roundworm) and Trichuris trichiura (the whipworm). A. lumbricoides eggs are rounder when fertilized while T. trichiura eggs have a barrel shape with hyaline plugs at each end. Both species have complex life cycles involving egg embryonation in soil before infecting a new host. A. lumbricoides and T. trichiura remain endemic in many tropical areas and are among the most common intestinal parasites worldwide.
1. Ascaris lumbricoides is the most common intestinal parasite found worldwide, especially in rural areas and among children.
2. It has a life cycle involving eggs that are ingested and develop into adults worms in the small intestine, causing symptoms like abdominal pain.
3. Diagnosis involves finding eggs in stool samples under a microscope; treatment involves a single dose of albendazole or mebenazole.
Hookworm is a parasitic nematode that infects the small intestine and is a major cause of iron-deficiency anemia globally. Two species infect humans - Ancylostoma duodenale and Necator americanus. The worms attach to the small intestine where the female lays thousands of eggs daily that are passed in feces. If soil contaminated with feces comes into contact with human skin, larvae can penetrate and migrate through tissues before reaching the intestine. This causes a rash and eosinophilia. In the intestine, the worms feed on blood, causing microcytic anemia. Over 900 million people are infected worldwide, especially in tropical areas with
The document discusses several species of cestodes (tapeworms), identifying their key morphological features and life cycles. It describes Dipylidium caninum, which infects dogs and cats and has segments resembling cucumber seeds. Taenia solium, the pork tapeworm, infects humans and pigs and can cause cysticercosis. Echinococcus multilocularis is a small tapeworm that infects canines and causes alveolar echinococcosis in intermediate hosts. The document examines cestode anatomy and identifies characteristics used in their classification.
Ascaris lumbricoides, commonly known as the large roundworm, is the most prevalent intestinal nematode parasite of humans. It inhabits the small intestine and can cause complications like intestinal obstruction. The adult female worm is 20-35cm long and lays hundreds of thousands of eggs per day that are passed in feces. When ingested, the eggs hatch in the intestines releasing larvae that penetrate the intestinal wall, travel to the lungs, and are then swallowed making their way back to the small intestine where they mature into adult worms.
Plant nematology is the study of nematodes, or roundworms, that are parasites of plants. These plant-parasitic nematodes can cause significant damage to crops, resulting in billions of dollars in losses worldwide ⁵. There is a lot of research being done to understand the interactions between parasitic nematodes and their plant hosts, and to develop new ways to control these pests ⁴. Is there anything specific you would like to know about plant nematology?
Source: Conversation with Bing, 13/7/2023
(1) (PDF) INTRODUCTORY-NEMOTOLOGY | ashish chaudhary - Academia.edu. https://www.academia.edu/34273375/INTRODUCTORY_NEMOTOLOGY.
(2) Plant Nematology Lab - University of Leeds. http://www.fbs.leeds.ac.uk/nem/.
(3) Plant Nematology: , 2nd Edition - Google Books. https://books.google.com/books/about/Plant_Nematology.html?id=LTv7AgAAQBAJ.
(4) Nematology - Wikipedia. https://en.wikipedia.org/wiki/Nematology.
(5) Plant Nematology | NHBS Academic & Professional Books. https://www.nhbs.com/plant-nematology-book.
1. Ascaris lumbricoides, commonly known as the large roundworm, infects humans through ingestion of its eggs from contaminated food, water, or soil.
2. The eggs hatch in the intestines, and the larvae migrate through the lungs before maturing into adult worms in the small intestine.
3. Symptoms range from mild to severe and include intestinal obstruction, pneumonia, and malnutrition. Diagnosis involves finding eggs in stool or adult worms after treatment. Prevention focuses on proper sanitation and hygiene.
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
This document describes ascariasis, caused by the roundworm Ascaris lumbricoides. It is most common in children in tropical areas with poor sanitation. The worms live in the small intestine and the female can lay up to 200,000 eggs daily that are passed in feces. When eggs are ingested, they hatch in the intestines releasing larvae that migrate through organs before maturing in the lungs and being swallowed to the intestines. Heavy infections can cause malnutrition, obstruction, and other complications. Diagnosis involves finding eggs in stool or worms. Treatment includes mebendazole or pyrantel pamoate. Prevention relies on proper sanitation and hygiene.
Nematodes are roundworms that range in length from 90 μm to 1000 mm. They have an anterior mouth and posterior anus. Their life cycle involves hatching from eggs as larvae and molting through different larval stages to become adults. Pinworm (Enterobius vermicularis) is a common intestinal nematode. Females are 10mm long while males are 3mm. It has a direct life cycle. Pinworm infection is widespread, with over 1 billion cases globally. The parasite's eggs are deposited on the skin at night and spread through contaminated surfaces. Common symptoms include irritation and itching. Diagnosis involves examining adhesive tape touched to the skin under a microscope for eggs. Treatment and prevention
This document discusses Ascaris lumbricoides, the roundworm. It describes the morphology of the adult worms and eggs. The lifecycle is completed within a single human host. Symptoms of infection can include intestinal or pulmonary disease. Diagnosis is made by identifying eggs in stool samples. Treatment involves anthelmintic drugs. Prevention focuses on proper sanitation and hygiene.
This document provides information about protozoa. It begins by defining protozoa as eukaryotic, unicellular organisms that lack cell walls and use cilia, flagella, or pseudopodia for motility. There are around 20,000 protozoan species, most of which are free-living in water or soil. Some can be parasitic or symbiotic. Important medically relevant protozoa include Entamoeba histolytica and Giardia lamblia, which can cause intestinal infections. Other protozoan diseases mentioned are African sleeping sickness caused by Trypanosoma brucei and Chagas disease caused by Trypanosoma cruzi. The document also briefly discusses helmin
This document discusses several intestinal nematodes including Ascaris lumbricoides (roundworm), Trichuris trichiura (whipworm), Enterobius vermicularis (pinworm), and hookworms. It provides details on the morphology, life cycles, pathogenesis, clinical features, diagnosis, treatment and prevention of these parasites. Intestinal nematodes can cause symptoms ranging from mild to severe depending on the worm burden. Diseases result from nutrient deficiency, intestinal obstruction, or blood loss caused by hookworms. Sanitation and hygiene practices like handwashing and use of toilets are important for prevention.
Hookworms are intestinal parasitic roundworms that infect the small intestine. They have a direct lifecycle where the infective third stage larva penetrates the skin and migrates through the lungs before reaching the small intestine to mature and reproduce. Eggs are passed in feces. Pathogenesis is due to the host immune response to migrating larvae, mechanical damage from larval migration, effects of adult worms in the intestines including blood loss. Common symptoms include iron deficiency anemia.
Ascaris lumbricoides, also known as the giant intestinal roundworm, is a parasitic nematode that infects the small intestine of humans. It has a worldwide distribution, especially in tropical and subtropical areas with poor sanitation. The adult worms can reach lengths of 20-35 cm in females and 15-30 cm in males. The life cycle involves fertilized eggs passing in feces and developing into infective larvae outside the body. People become infected by ingesting these embryonated eggs. The larvae hatch in the intestine, penetrate the intestinal wall, migrate through the lungs, are swallowed and pass into the intestine where they mature into adult worms. Most infections are asymptomatic, but symptoms can include abdominal pain,
Ascaris lumbricoides is a common roundworm parasite that infects an estimated 1 billion people worldwide (1 out of 4 people), being most prevalent in underdeveloped areas with poor sanitation. It is transmitted via ingestion of eggs from contaminated food or soil and causes symptoms ranging from abdominal discomfort to pulmonary issues during larval migration. Treatment involves anthelmintic drugs like mebendazole or albendazole and prevention focuses on improved sanitation and limiting the use of human feces as fertilizer.
1. The document describes the life cycles of several parasitic roundworms (nematodes) that infect humans, including Ascaris lumbricoides, Enterobius vermicularis, Trichuris trichiura, Ancylostoma duodenale, Strongyloides stercoralis, and Trichinella spiralis.
2. It provides details on the morphology, life stages, transmission, localization in the host, and clinical manifestations of each parasite.
3. The life cycles generally involve eggs passing in feces and developing into infective larvae in the soil, which then penetrate the skin or are ingested to develop into adult worms that reproduce sexually and release eggs to complete the
This document summarizes several types of parasitic helminths (worms) that can infect humans. It describes the life cycles, geographical distribution, clinical presentation, diagnosis, and treatment of important nematode infections including hookworms, Strongyloides, ascariasis, enterobiasis, trichuriasis, and filariasis. Key points are that these soil-transmitted helminths typically have complex life cycles involving larval stages in soil that infect via skin penetration or ingestion, causing anaemia, pulmonary symptoms, or intestinal obstruction in heavy infections. Diagnosis involves finding eggs or larvae in stool or tissue samples, and treatment consists of anthelmintic medications like albendazole or me
This document provides information on the taxonomy, morphology, life cycles, pathogenesis, clinical features, diagnosis, and treatment of various helminth parasites. It describes the characteristics of nematodes and discusses specific nematodes like Trichuris trichura and Enterobius vermicularis. For T. trichura, it provides details on its morphology, life cycle, clinical manifestations including rectal prolapse, and microscopic identification of eggs in stool samples. For E. vermicularis, it discusses epidemiology in children, morphology of adult worms and eggs, life cycle involving nocturnal emergence of females, and diagnosis using scotch tape tests. Treatment involves repeated doses of albendazole or mebendazole
Enterobius vermicularis, commonly known as pinworm or seat worm, is a parasitic nematode that infects the human intestine. It has a two month lifecycle where sexually mature worms inhabit the small and large intestines and lay eggs in the perianal area. Infection occurs when eggs are ingested and hatch in the small intestine. Pinworms are a common cause of itching and irritation around the anus but often cause no symptoms. Diagnosis involves detecting eggs on perianal skin or microscopic examination of stool samples. Treatment involves administering anthelmintic drugs to infected individuals and members of their household. Prevention focuses on good personal hygiene like handwashing and cutting fingernails short
1. Ascaris lumbricoides, or the roundworm, is one of the most common intestinal nematodes infecting humans. It inhabits the small intestine and can reach lengths of over 20 cm in females.
2. The life cycle involves ingestion of infective eggs from contaminated food, water, or soil. Inside the intestine, the larvae hatch and mature into adults. Females produce thousands of eggs daily that are passed in feces.
3. Symptoms range from mild to severe and include abdominal pain, nausea, intestinal obstruction, or migration of larvae to other organs causing pneumonia. Complications can also include appendicitis or pancreatitis. Diagnosis is made by finding eggs in
The document discusses several species of nematodes (roundworms) that can infect humans, including their morphology, life cycles, and epidemiology. It focuses on two specific species: Ascaris lumbricoides (the large intestinal roundworm) and Trichuris trichiura (the whipworm). A. lumbricoides eggs are rounder when fertilized while T. trichiura eggs have a barrel shape with hyaline plugs at each end. Both species have complex life cycles involving egg embryonation in soil before infecting a new host. A. lumbricoides and T. trichiura remain endemic in many tropical areas and are among the most common intestinal parasites worldwide.
1. Ascaris lumbricoides is the most common intestinal parasite found worldwide, especially in rural areas and among children.
2. It has a life cycle involving eggs that are ingested and develop into adults worms in the small intestine, causing symptoms like abdominal pain.
3. Diagnosis involves finding eggs in stool samples under a microscope; treatment involves a single dose of albendazole or mebenazole.
Hookworm is a parasitic nematode that infects the small intestine and is a major cause of iron-deficiency anemia globally. Two species infect humans - Ancylostoma duodenale and Necator americanus. The worms attach to the small intestine where the female lays thousands of eggs daily that are passed in feces. If soil contaminated with feces comes into contact with human skin, larvae can penetrate and migrate through tissues before reaching the intestine. This causes a rash and eosinophilia. In the intestine, the worms feed on blood, causing microcytic anemia. Over 900 million people are infected worldwide, especially in tropical areas with
The document discusses several species of cestodes (tapeworms), identifying their key morphological features and life cycles. It describes Dipylidium caninum, which infects dogs and cats and has segments resembling cucumber seeds. Taenia solium, the pork tapeworm, infects humans and pigs and can cause cysticercosis. Echinococcus multilocularis is a small tapeworm that infects canines and causes alveolar echinococcosis in intermediate hosts. The document examines cestode anatomy and identifies characteristics used in their classification.
Ascaris lumbricoides, commonly known as the large roundworm, is the most prevalent intestinal nematode parasite of humans. It inhabits the small intestine and can cause complications like intestinal obstruction. The adult female worm is 20-35cm long and lays hundreds of thousands of eggs per day that are passed in feces. When ingested, the eggs hatch in the intestines releasing larvae that penetrate the intestinal wall, travel to the lungs, and are then swallowed making their way back to the small intestine where they mature into adult worms.
Plant nematology is the study of nematodes, or roundworms, that are parasites of plants. These plant-parasitic nematodes can cause significant damage to crops, resulting in billions of dollars in losses worldwide ⁵. There is a lot of research being done to understand the interactions between parasitic nematodes and their plant hosts, and to develop new ways to control these pests ⁴. Is there anything specific you would like to know about plant nematology?
Source: Conversation with Bing, 13/7/2023
(1) (PDF) INTRODUCTORY-NEMOTOLOGY | ashish chaudhary - Academia.edu. https://www.academia.edu/34273375/INTRODUCTORY_NEMOTOLOGY.
(2) Plant Nematology Lab - University of Leeds. http://www.fbs.leeds.ac.uk/nem/.
(3) Plant Nematology: , 2nd Edition - Google Books. https://books.google.com/books/about/Plant_Nematology.html?id=LTv7AgAAQBAJ.
(4) Nematology - Wikipedia. https://en.wikipedia.org/wiki/Nematology.
(5) Plant Nematology | NHBS Academic & Professional Books. https://www.nhbs.com/plant-nematology-book.
1. Ascaris lumbricoides, commonly known as the large roundworm, infects humans through ingestion of its eggs from contaminated food, water, or soil.
2. The eggs hatch in the intestines, and the larvae migrate through the lungs before maturing into adult worms in the small intestine.
3. Symptoms range from mild to severe and include intestinal obstruction, pneumonia, and malnutrition. Diagnosis involves finding eggs in stool or adult worms after treatment. Prevention focuses on proper sanitation and hygiene.
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptxHolistified Wellness
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nematodes.pptx
1. Class Nematoda -
The Roundworms
Introduction:
Nematodes comprise the group of organisms containing the
largest number of helminth parasites of humans. They are
unsegmented, bilaterally symmetrical, and exhibit great
variation in their life cycles. Generally, they are long-lived (1-
30+ years).
Both free-living and parasitic forms - some can have both
free-living and parasitic stages in their life cycle.
Vary greatly in size - from a few millimeters to over a meter.
Male worms - frequently have a curved or coiled posterior
end with copulatory spicules; Some species exhibit a
copulatory bursa.
2. Class Nematoda -
The Roundworms
The adult anterior - may have hooks, teeth, or cutting plates in
the buccal cavity. These are used for attachment.
Body is complex - the outer body surface is a cuticle, there
are muscle layers underneath.
Internal organs - include a complex nerve cord, a well-
developed digestive system and complete reproductive
organs. Males have testes, vas deferens, seminal vesicle
and an ejaculatory duct. Females have ovaries, oviduct,
seminal receptacle, uterus and vagina.
Reproductive capacity - proportional to complexity of life
cycle.
3. Class Nematoda -
The Roundworms
Humans are definitive hosts.
Arthropods may serve as intermediate hosts
and/or vectors. Many nematodes require no
intermediate host.
The adult female produces fertilized eggs, or
larvae which may be infective to new host.
Eggs may be immediately infective after
ingestion by humans.
4. Class Nematoda -
The Roundworms
Eggs or larvae require a period of development
in the environment to become infective.
Eggs or larvae are transmitted to a new host by
an insect.
Developing larvae go through a series of 4 molts
with the third stage, the filariform larva, most
often being the infective stage.
5. Class Nematoda -
The Roundworms
Infection with roundworms can be by ingestion of
infective eggs or larvae, by larval penetration of skin, or
by transmission of larvae through insect bite.
About one-half of the nematodes parasitic for man are
intestinal, the others are found in various tissues.
Pathogenicity of intestinal nematodes may be due to
larval migration through tissue, piercing of intestinal
wall, blood loss, or allergic reactions to secretions of
adults or larvae.
6. Class Nematoda -
The Roundworms
Terminology:
Filariform larvae - the 3rd or infective stage; Long,
thread-like; Designed for penetration.
Rhabditiform larvae - characterized by the
presence of a muscular esophagus and bulbular
pharynx. The worms leaving the egg are termed
“rhabditiform” larvae.
7. Class Nematoda -
The Roundworms
Egg - characteristic of the genus. Size & shape are
relatively consistent.
Larvae - undergo several molts (third stage usually
the infective stage).
Adult - varies in size from genus to genus; Range
from less than 1 mm to over one meter.
8. Class Nematoda -
The Roundworms
General life cycle of intestinal nematodes:
Humans ingest infective eggs. Hookworm and
Strongyloides stercoralis are exceptions. In these,
filariform larvae penetrate the skin to gain entry.
Larvae hatch in intestine.
Male and female adults develop in the intestine. With
Ascaris lumbricoides, hookworms, and Strongyloides
stercoralis larvae penetrate the intestinal mucosa and
initiate a heart - lung cycle enroute to the intestinal tract
to mature to adults.
9. Class Nematoda -
The Roundworms
Fertilized eggs are produced.
Diagnostic stages, eggs or larvae, exit the host
in its feces.
Larvae develop within the egg in warm, moist
soil (except for Strongyloides stercoralis, whose
eggs hatch in the intestine, with larvae passing
in the feces).
10. Class Nematoda -
The Roundworms
Enterobius vermicularis - the pinworm.
Most common helminth infection in the U.S.A.
Transmission is direct, person-to-person.
Egg is infective immediately or within hours of
being shed by the female.
Common worldwide but more prevalent in
temperate climates.
Higher prevalence in Caucasians than in
Negroes.
It is a group infection especially common
among children. Very often associated with
low sanitation and hygiene.
Humans are the only known host. Dogs and
cats are not infected.
11. Class Nematoda -
The Roundworms
Life cycle:
Eggs are ingested, hatch in intestine,
larvae mature to adults.
Gravid females migrate to the perianal
area at night to lay eggs.
Eggs develop to infective stage within 4-6
hours. Eggs can survive for extended
periods in cool, moist environment.
Eggs are found rarely in fecal samples;
Release is most often external to the
intestines. Dying worms may release
eggs in the bowel.
12. Class Nematoda -
The Roundworms
Adults - female: creamy white, ~ 8-13 mm
long, with sharply pointed tails; Wing-like
flaps (cervical alae) at head end; Male:
small (2-5 mm) with strongly curved
posterior.
Eggs - 50 to 60 x 20 to 32 microns, broadly
oval, and flattened on one side.
Compressed laterally; Normally are
embryonated (contain a larva).
13. Class Nematoda -
The Roundworms
Diagnosis:
Recovery and identification of
eggs or adults from the perianal
region utilizing the cellophane
tape preparation.
Specimens must be collected the
first thing in the morning upon
waking, especially before bathing
or bowel movements.
Eggs are rarely found in fecal
samples because release is
usually external to the intestines.
14. Class Nematoda -
The Roundworms
Major pathology and symptoms:
One third of all cases are asymptomatic.
Infections rarely cause serious lesions.
Symptoms associated with the migration
of the female out of the anus to lay her
eggs include: perianal itching, nausea or
vomiting, loss of sleep, irritability,
irritation of the intestinal mucosa, and
vulval irritation in females due to
migrating worms entering the vagina
instead of the re-entering anus.
15. Class Nematoda -
The Roundworms
Trichuris trichiura - the whipworm.
Life cycle:
Infective, fully embryonated eggs are
ingested, larvae hatch in small intestine,
penetrate and develop in the intestinal
villi, return to lumen and migrate to the
area of the cecum.
Larvae mature and live in the colon.
Worms embed their anterior portion (as
much as two-thirds of the worm) into the
mucosa.
16. Class Nematoda -
The Roundworms
Life Cycle: (continued)
Barrel-shaped eggs are released
into the stool.
Eggs must undergo
development in the soil for
approximately 10 days to 3
weeks before they become
infective.
The worm’s life span is
estimated to be 4 - 8 years.
17. Class Nematoda -
The Roundworms
Morphology:
Adults - females: 35 to 50 mm
long, anterior two-thirds is
long and threadlike, expanding
into a broader posterior;
males: 30 to 45 mm long,
similar to female but exhibiting
a strong curvature of tail.
Eggs - 50 to 55 x 22 to 25
microns, barrel-shaped, with
clear polar plug at each end.
18. Class Nematoda -
The Roundworms
Diagnosis - recovery and identification
of eggs in the feces.
Major pathology and symptoms:
Slight infections - usually asymptomatic.
Heavy infections - surface of colon is
matted with worms which causes
bloody or mucous diarrhea.
weight loss and weakness - infections
with 200 or more worms in children may
cause a chronic dysentery, profound
anemia and growth retardation.
19. Class Nematoda -
The Roundworms
Major pathology and symptoms:
(continued)
Abdominal pain and tenderness.
increased peristalsis and rectal
prolapse, especially in children.
20. Class Nematoda -
The Roundworms
Distribution:
In the U.S.A., prevalent in the warm, humid
climate of the southeastern states. Commonly
found in refugees from tropical areas.
The third most common intestinal helminth
infection.
Higher prevalence in warm countries and areas
of poor sanitation, especially in countries which
utilize "night soil" for fertilizer.
Common among children and in the
institutionalized mentally retarded.
Commonly seen along with Ascaris lumbricoides
because of the similar mode of infection.
21. Class Nematoda -
The Roundworms
Ascaris lumbricoides - Large Intestinal Roundworm
Life cycle: (complex, involves a heart-lung cycle)
Humans ingest embryonated eggs containing
infective larvae.
Larvae hatch from the eggs in the small intestine,
penetrate the intestine wall, enter the
bloodstream, migrate to the liver, travel to the
lung via the blood stream.
Larvae break out of lung capillaries into alveoli,
travel to the bronchioles, and are coughed up to
the pharynx. They are swallowed and return to
the intestine. Two molts to 4th stage larvae take
place in alveoli.
22. Class Nematoda -
The Roundworms
Life cycle: (continued)
Larvae mature to adults in the small intestine.
Worms do not attach to the intestinal wall, but
maintain their position by constant movement.
Worms have a life span of approximately 1
year.
Undeveloped eggs are passed in the feces.
These eggs develop in soil and are infective
after two weeks to one month. The egg shell is
very thick and resistant to environmental
changes.
Eggs can remain infective for up to 5 years if
protected from direct sunlight and desiccation.
23. Class Nematoda -
The Roundworms
Morphology:
Adults - males are 15 to 30 cm long,
with strongly curved tails; females are
20 to 35 cm long, with straight tails.
Eggs - one female produces 200,000
per day. The egg has an outer shell
membrane which is heavily mamillated.
This layer is sometimes rubbed off in
passage down the fecal stream.
Infertile eggs often appear longer, and
thinner shelled.
24. Class Nematoda -
The Roundworms
Diagnosis -
Identification of eggs and/or adults in fecal samples.
Major pathology and symptoms:
Pneumonia associated with migration of larvae in
the lungs.
Obstruction of the intestines, appendix, or
common bile duct.
Vomiting and abdominal pain.
May cause malnutrition in children with heavy
infections or poor diet.
Some infections are asymptomatic.
25. Class Nematoda -
The Roundworms
Distribution - Worldwide, similar to
T. trichiura; Eggs thrive best in
soil with dense shade, heavy rain
and warm climate.
General Information:
Ascaris is the largest intestinal
nematode.
The second most common
helminth infection in the U.S.
26. Class Nematoda -
The Roundworms
Mixed infections with T. trichiura are
common. If both are present, treat the
Ascaris infection first, since it is the more
likely of the two to migrate.
Non-specific treatment or administration of
anesthesia can cause worms to migrate,
including penetrating the intestinal wall;
forcing through the pyloric and cardiac
valves of the stomach, thus entering the
esophagus; or crawling into the common
bile duct.
Adult worms may rarely be recovered from
the anus, mouth, throat or nose.
27. Class Nematoda -
The Roundworms
Necator americanus - The New World hookworm
Ancylostoma duodenale - The Old World hookworm
Life cycle:
Eggs shed in soil hatch within 48 hours,
becoming rhabditiform larvae (1st & 2nd stages).
After ~ 7 days, worms stop feeding and molt,
transforming from the rhabditiform larvae to
infective filariform larvae.
Infections are acquired when the filariform larvae
penetrates the skin of a human.
Female Male
Hookworm egg
28. Class Nematoda -
The Roundworms
Life cycle: (continued)
Larvae enter the lymphatic system or
bloodstream, and travel to the lungs. After
maturating in the lungs, they migrate up the
trachea to be swallowed and reach the small
intestine, where they mature to adults.
Immature adults attach to the intestinal mucosa
by means of their stout mouth parts and suck
blood and tissue juices of the host.
About five weeks after infection, the worms have
undergone a final molt to become sexually
mature adults. Fertilization occurs, and the
females begin to release eggs. Worm life span is
about 1 year.
Hookworm rhabditiform larva
Hookworm filariform larva
29. Class Nematoda -
The Roundworms
Morphology:
Rhabditiform larvae - long buccal
cavity, indistinct genital primordium.
Filariform larvae lose oral structures &
have sharp pointed tails.
Adults - males: 7 to 11 mm long with a
copulatory bursa; females: 8 to 15 mm
long.
Eggs - 55 to 70 x 35 to 40 microns; very
thin shell; usually seen in the 8 - 32 stage
of cleavage.
Hookworm rhabditiform larva
Hookworm filariform larva
Hookworm egg
30. Class Nematoda -
The Roundworms
Diagnosis:
Recovery and identification of eggs
(rarely larvae) in the feces.
Cannot differentiate Hookworm species
by egg appearance.
To determine if a significant infection is
present, count the number of eggs on a
direct smear of the unconcentrated
specimen. Five eggs per smear
indicates a light infection; 20 or more
eggs is clinically significant; 100 or
more is indicative of a very heavy
infection.
31. Class Nematoda -
The Roundworms
Major pathology and symptoms:
Serpent-like tunneling at site of penetration may
occur (cutaneous larva migrans).
During migration through the lungs, patients may
experience a sore throat and / or bloody sputum.
Heavy intestinal infections may result in enteritis,
anemia, weakness, and loss of strength due to the
anemia.
Chronic infections may experience anemia,
weakness, weight loss and gastro-intestinal
symptoms.
Nutritional and disease factors are commonly
seen in endemic areas. Children may exhibit
stunted growth and intellectual development.
Blood loss can be up to 100 milliliters/day.
32. Class Nematoda -
The Roundworms
Distribution:
A. duodenale - Europe and south America
N. americanus - North America and Africa
Moist, warm regions of the world where the
skin frequently contacts the soil is optimal
for infection, especially in areas of poor
sanitation.
Ancylostoma duodenale adults
Necator americanus adults
33. Class Nematoda -
The Roundworms
Strongyloides stercoralis - The Threadworm
Life cycle: (very complex)
Infective third stage filariform larvae
penetrate skin, enter the lymphatics or
bloodstream.
Larvae migrate to the lungs, break out of
lung capillaries into alveoli.
After maturation, larvae travel to the
pharynx, are swallowed, and return to the
intestine.
Larvae mature to adults and attach to the
mucosa of the small intestine.
Strongyloides stercoralis rhabditiform larva
Strongyloides stercoralis filariform larva
34. Class Nematoda -
The Roundworms
Life cycle: (Continued)
Parthogenetic Females only - no parasitic
males. Females are capable of unisexual
reproduction, no fertilization required.
Produce viable eggs.
Eggs hatch in mucosa.
Larvae: Are passed in feces, live in the soil,
mature into a free-living adult males and
females, which produce eggs; Rhabditiform
larvae feed in soil and develop into
infective stage larvae which penetrate the
skin; First stage larvae develop into
infective stage larvae in the intestine
(autoinfection).
Strongyloides stercoralis rhabditiform larva
Strongyloides stercoralis filariform larva
35. Class Nematoda -
The Roundworms
Morphology:
Rhabditiform larvae - short buccal cavity;
large, prominent genital primordium.
Filariform larvae - tail has a notch in it, in
contrast with the filariform larva of
hookworms.
Must be able to differentiate these from
hookworm larvae.
Eggs hatch in the intestine (not usually
passed in stool specimens). Eggs resemble
hookworm eggs, but are embryonated.
Buccal cavity of rhabditiform larva
Notch in tail of filariform larva
36. Class Nematoda -
The Roundworms
Diagnosis:
Recovery and identification of
larvae in the feces.
Recovery and identification of
eggs in duodenal drainage.
37. Class Nematoda -
The Roundworms
Major pathology and symptoms:
Skin – allergic reactions; raised, itchy, red
blotches at the site of larval penetration.
Lungs – pneumonia.
Intestinal - abdominal pain, diarrhea,
vomiting, weight loss, anemia,
eosinophilia. Light infections usually
asymptomatic; Heavy infection - bowel
becomes edematous and congested.
Death occurs in immunosuppressed
patients due to heavy autoinfection.
38. Class Nematoda -
The Roundworms
Strongyloides stercoralis - The Threadworm (Continued)
Distribution - worldwide, similar to hookworm.
While hookworm infection dies out over a period of
years after the patient has moved from an endemic area,
strongyloidiasis may persist for years, due to
autoinfection (internal infection).
In cases with severe diarrhea, Strongyloides eggs may
be present in stool specimens. These must be
differentiated from hookworm eggs. Strongyloides eggs
contain well-developed larvae. Hookworm eggs do not
have well developed larvae until passed from the body
and mature for one to two weeks in the soil.
39. Class Nematoda -
The Roundworms
Blood and Tissue-Dwelling Nematodes
Trichinella spiralis – trichinosis
Due to meat inspection programs, not very
prevalent in U.S.A. When seen, it is usually
due to home butchering and meat preparation.
Outbreaks most commonly associated with
pork.
Trichinella spiralis is a parasite of carnivorous
mammals. It is common in rats and in swine
fed uncooked garbage and slaughterhouse
scraps.
Human infections occur most often as a result
of consumption of raw or undercooked pork.
40. Class Nematoda -
The Roundworms
Trichinella spiralis – trichinosis
Life cycle:
Infective stage larvae are ingested in
meat products.
Tissue is digested, larvae are freed in the
intestine. They mature into adult males
and females.
Female in mucosa releases larvae.
These disseminate throughout the body
via the bloodstream.
Larvae encyst in striated muscle.
41. Class Nematoda -
The Roundworms
Trichinella spiralis - trichinosis
Morphology - females are 3.5 mm long;
males measure 1.5 mm long; larvae measure
100 microns long.
Diagnosis - Identification of encysted larvae
in muscle biopsy. Serology becomes
positive 3 to 4 weeks after infection. A
history of eating undercooked pork, deer,
walrus or bear is indicative whenever
appropriate symptoms appear.
42. Class Nematoda -
The Roundworms
Trichinella spiralis – trichinosis
Major pathology and symptoms:
Fever, muscle pain, bilateral periorbital edema,
and increased eosinophil count
Intestinal phase – small intestine edema and
inflammation, nausea, vomiting, abdominal
pain, diarrhea, headache, and fever.
Migrational phase - high fever (104 degrees),
blurred vision, edema, cough and pleural
pains.
Muscle phase – acute, local inflammation with
edema and pain.
43. Class Nematoda -
The Roundworms
Trichinella spiralis – trichinosis
Distribution:
Cosmopolitan among meat-eating
populations, highest incidence is
reported from China, common in
Spain, France, Italy, and Yugoslavia.
Prevalence in U.S.A. is about 4%
based on autopsy studies.
Only about 100 cases are recognized
and reported per year in the U.S.A.
44. Class Nematoda -
The Roundworms
Dracunculus medinensis – The Guinea Worm
Overview:
An important parasite in the Middle East,
central India and Pakistan. Also found in
Africa in the Sudan and scattered through
central equatorial regions, and on its west
coast.
It is believed to no longer occur in the
Western Hemisphere.
Sometimes classified with the filarial
worms, but Dracunculus is not a true
filaria.
Blister containing Dracunculus medinensis
Adult Dracunculus emerging from broken blister
45. Class Nematoda -
The Roundworms
Dracunculus medinensis – The Guinea Worm
Life cycle:
Infective stage exists in a water flea (copepod –
the intermediate host).
Humans become infected by drinking water
containing the infected copepod.
Larvae penetrate the digestive tract to enter the
deep connective tissues where they mature in
about 1 year.
Females migrate to the subcutaneous tissue
(usually the skin of the extremities).
Females release larvae which leave the human
through ruptured blisters on the skin.
The larvae enter the water and are ingested by
copepods.
46. Class Nematoda -
The Roundworms
Dracunculus medinensis – The Guinea Worm
Morphology –
Males measure 40mm in length.
Females measure 800mm in length.
Diagnosis -
Visual observation of skin blister. The worm’s
serpentine presence beneath skin can be
seen.
Induce release of larvae from the skin ulcer by
applying cold water.
47. Class Nematoda -
The Roundworms
Dracunculus medinensis – The Guinea Worm
Major pathology and symptoms –
Mild allergic symptoms such as urticaria
during the migration phase.
A papule develops into a blister with
localized erythrema and tenderness.
Generalized symptoms include nausea,
vomiting, diarrhea, and possibly asthma
attacks.
Additional complications include
secondary bacterial infections, permanent
damage to joints.
Distribution - Middle East and Africa.
48. Class Nematoda -
The Roundworms
The Filarial Worms
The Filariae are long thread-like nematodes. Eight species inhabit
portions of the human subcutaneous tissues and lymphatic system.
Adults of all species are parasites of vertebrate hosts.
Female worms produce eggs. The eggs modify, becoming elongated
and worm-like in appearance and adapting to life within the vascular
system.
Modified eggs, referred to as microfilariae, are capable of living a
long time in the vertebrate host, but cannot develop further until
ingested by an intermediate host and vector, an insect.
Microfilariae transform into infective larvae in the insect and are
deposited in the next host when the insect takes a blood meal.
49. Class Nematoda -
The Roundworms
The Filarial Worms
General life cycle:
Human infection is acquired when infective
larvae enter the skin at the arthropod’s feeding
site.
Larval migration and development takes place
in tissue.
Adults are in various tissues (according to
species). They mature and produce
microfilariae.
50. Class Nematoda -
The Roundworms
The Filarial Worms
Wuchereria bancrofti:
“Bancroft's Filariasis.” A blood & lymphatic
dweller. The infection often results in
elephantiasis.
Vectors - Culex, Aedes, & Anopheles
mosquitoes.
Diagnosis - Detection and identification of
microfilaria in stained blood smears. Exhibits
a marked circadian migration, best seen at
night after 10 P.M.
Morphology - Microfilariae are sheathed, and
the nuclear column does not extend to tip of
tail.
Wuchereria bancrofti microfilaria in blood smear
51. Class Nematoda -
The Roundworms
The Filarial Worms
Wuchereria bancrofti:
Major pathology and symptoms –
Swelling, due to allergic reaction
occurring around adult worms,
produces obstruction & elephantiasis.
Each individual reacts differently.
Very few develop elephantiasis, but in
some this is extensive.
52. Class Nematoda -
The Roundworms
The Filarial Worms
Brugia malayi:
“Malayan filariasis.” A blood & lymphatic dweller.
The infection can cause elephantiasis, but is not
as disfiguring or common as with Wuchereria
bancrofti.
Vectors - Mansonia, Anopheles & Aedes
mosquitoes.
Diagnosis - Detection and identification of
microfilaria in stained blood smears.
Morphology - Microfilariae are sheathed, nuclear
column extends to tip of tail with two nuclei near
end of tail, one in a swelling just short of tail’s
end, the other in the end of the tail.
Brugia malayi microfilariae in blood smear
53. Class Nematoda -
The Roundworms
The Filarial Worms
Brugia malayi:
Major pathology and symptoms -
Swelling, due to allergic reaction
occurring around adult worms,
produces obstruction & elephantiasis.
Each individual reacts differently. More
often asymptomatic than infections
with W. bancrofti.
54. Class Nematoda -
The Roundworms
The Filarial Worms
Onchocerca volvulus:
The “blinding filaria.” Infections involve the
dermis and subcutaneous tissues, where
adults gather within nodules.
Vector - Simulium flies (blackfly, or buffalo
gnat).
Diagnosis - microfilariae are found in skin
scrapings from around nodules.
Morphology - Microfilariae not sheathed;
found only in skin, not in the blood stream.
55. Class Nematoda -
The Roundworms
The Filarial Worms
Onchocerca volvulus:
Major pathology and symptoms -
Characterized by fibrotic nodules which
encapsulate adults, usually on the trunk in
Africa, and on the head in central America.
A progressive, allergic skin rash develops.
Blindness occurs due to the presence of
microfilariae in ocular structures. This
parasite is a major cause of blindness in
Africa. Control is difficult because
Simulium flies breed in running water.
56. Class Nematoda -
The Roundworms
The Filarial Worms
Loa loa:
The “eyeworm.” Infections involve the dermis
and subcutaneous tissues (Calabar swellings).
Vector - Crysops (mango fly), a large fly with
biting mouthparts.
Diagnosis - Usually made from clinical
symptoms, but if laboratory confirmation is
required, blood should be drawn between 11
am & 1 pm.
Diagnosis - Microfilariae are sheathed, nuclear
column extends to tip of tail.
57. Class Nematoda -
The Roundworms
The Filarial Worms
Loa loa:
Major pathology and symptoms -
Infections cause a localized
subcutaneous edema, particularly
around the eye, because of larval
migration and death in capillaries.
Living adults cause no inflammation;
dying adults induce granulomatous
reactions.