University:
American Career College
Course:
MA700 | Clinical Procedures and Pharmacology
Academic year:

2021
Views:

142

Pages:

44
Author:

VNever

Introduction to Parasitology & Cestoda- Diphyllobothrium, Spirometra 02/14/21 Dr.tabatabaie 2 Symbiosis: 1-Commensalism ,an association between two organisms in which one benefits and the other derives neither benefit nor harm 2-Mutualism, describes the ecological interaction between two or more species where each species has a net benefit. 3-Parasitism, In parasitism, the parasite benefits at the host's expense. 02/14/21 Parasite Parasite:In parasitism, it is the benefited partner. It is an animal organism which lives in or on the host in order to obtain nourishment and shelter from the host as well as does harms to the host. 02/14/21 Kinds of Parasites endoparasite ectoparasite temporary, passing parasite permanent, fixed parasite obligatory, necessary parasite facultative , optional parasite accidental,Incidental or unexpected parasite opportunistic parasite monoxenous, heteroxenous(has more than one host) erratic or ectopic, unsettled parasite saprophyte VERSUS pathogene parasite 02/14/21 Endoparasite 02/14/21 Ectoparasite 02/14/21 Host ,In parasitism, it supplies the parasite with nourishment and shelter, it is the injured partner. Carrier ,A person who harbours parasite has no clinical symptoms, is an important source of infection in epidemiology. 02/14/21 Definitive (final) host ,harbours adult or sexually reproductive stage of a parasite. Intermediate host,harbours larval or asexually reproductive stage of a parasite, according to priority they are classified into first intermediate host, second intermediate host, third intermediate host. 02/14/21 • Reservoir hosts,are the vertebrate hosts which harbour the same species of parasite at same stage as a human host. They are an important source of infection in epidemiology. 02/14/21 Zoonosis, refers to animal’s diseases which can be transmitted to man. Vector: a living carrier (e.g. an arthropod) that transports a pathogenic organism from an infected to a non-infected host. A typical example is the female Anopheles mosquito that transmits malaria disease . We have two kinds vectors: Mechanical (just transport or transmission of the parasite) and biological(in addition transport, reproduction and evolution of the parasite) vectors 02/14/21 • Paratenic host or transport (transit)host,is an abnormal host in which some parasitic larvae can survive but can’t develop into adults. If the larvae have a chance to enter their suitable hosts, they can continue to develop into adults there. 02/14/21 Classification of Helminthes According to transmission methods • 1- Soil transmitted Helminthes : Ascaris, Hook worms • 2- Snail t. H. : Trematoda ( Schistosoma,….) • 3- Arthropods t. H. : Fillaria, Dracanculus medinensis • 4- Food and Meat t. H. : Taenia saginata, Taenia solium • 5- Direct t. H. ( contagious H.): Enterobius vermicularis,… 6- Sexual transmitted parasites : Transplacental infection . Trans mammary infection 7- Transfussion 02/14/21 Infection, Infestation Strain 02/14/21 parasitology • Medical Parasites: • - Protozoa • - Helminthes: • - Arthropoda • • 02/14/21 1- Platyhelminthes 2- Nemathelminthes 3- Nematomorpha 4- Acanthocephala 5- Annelida CLASSIFICATION of Protozoa 02/14/21 CLASSIFICATION of helminths Helmintholog y Platyhelminthes (Flat worms) Trematoda (Flukes) Ceastoda (Tape worms) 02/14/21 Nematohelminthes (Round worms) Nematoda Phylum Platyhelminthes Class: Ceastoda Order: - Cyclophyllidea: Taenia spp. , Echinococcus - Pseudophyllidea: Diphyllobothrium latum 02/14/21 • General characters of Cestoda: • The body of the typical cestode consists of 3 distinct regions: • scolex, neck, and strobila Flat, segmented body with various length (several mm ~ several meters) 1- an anterior attachment organ( scolex, as an attachment structure );scolex includes: - sucker ( bothria as grooves, bothridia,Acetabula) - rostellum- -hooklets(hooks to anchor the scolex to the host's intestinal wall), 2- neck region, germinal portion ,continually produces proglottids 3- a chain of segments or A series of proglotids( strobila) include: - Immature proglottids (No system has been set up or are not seen) - Mature p.(Each mature proglottid contains a set of reproductive organs of both sexes,male and female, All tapeworms are hermaphrodites, with each individual having both male and female reproductive organs. ) - Gravid p(uterus full of eggs). 02/14/21 Different Tracts of Cestoda • Digestive system degenerated, Cestodes have no gut or mouth but absorb nutrients directly from the host's gut. Tegument(Cover on the cestoda) play role of absorption tract , in addition to protecting role • Reproduction system : • all tapeworms are hermaphroditic *male and female organs are found in mature proglottids, Hermaphrodit ( cross-fertilization or self-fertilization). Tapeworms also lack a circulatory system(Blood system) and an organ specialized for gas exchange. 02/14/21 scolex 02/14/21 • The asexual process of forming segments is termed strobilation 02/14/21 India Ink Technique Note : less than 13 lateral uterine branches (one side). 02/14/21 • • • • Phylum: Platyhelminthes Class: Cestoidea Subclass: Cestoda Order: Pseudophyllidea – • • • • - Taxonomy Family Diphyllobothridae • Diphyllobothrium latum • Spirometra mansoni Diphyllobothrium latum Length: 3-10 m Scolex: elongated, almond shaped, 2 bothria Broader than long Multiple testes Bilobed ovary Rosette shaped uterus( the uterine pore is centrally located) as genital pore - Vitelline glands 02/14/21 24 D. latum Egg Scolex 02/14/21 Proglott ids Pseudophyllidean pattern Egg Cysticercus Cyclophyllidean pa Oncosphere Coracidium ADULT CESTOD E 02/14/21 Hyd Pseudophyllidean Pattern - Eggs containing coracidia leave the host with the feces to water - The coracidium escapes from the eggshell through the operculum and swims by means of its ciliated embryophore. -Coracidium is ingested by the first intermediate host (an aquatic arthtopod) within which the embryophore and metamorphoses into a procercoid in the host , s hemocel. -During development the oncosphere hooks are retained in a taillike structure called the cercomer -Then the first intermediate host is ingested by a second intermediate host (usually a fish),the procercoid migrates via the peritoneal cavity to various parts of the body,primarily the musculature -Here it grows and develops into a plerocecoid that shows the beginning of strobilation and a self-formed adult scolex. -The plerocercoid is infective to the definitive host -When ingested ,it attaches to the wall of the small intestine, where 02/14/21 aaie strobilation occurs. Cyclophyllidean Pattern 02/14/21 Diphyllobothrium latum Causal Agents: The cestode Diphyllobothrium latum (the fish or broad tapeworm), the largest human tapeworm in small intestine (intestinal ). Several other Diphyllobothrium species have been reported to infect humans, but less frequently; they include D. pacificum, D. cordatum, D. ursi, …. 02/14/21 Section of an adult D. latum containing many proglottids 02/14/21 Scolex of D. latum Proglottids of D. latum The most important feature or specifications 02/14/21 Diphyllobothriosis •Diphyllobothriasis occurs : Lake regions in Europe, America, Central Africa, Russia and Japan •(Not seen in Iran yet ) 02/14/21 Clinical Features Diphyllobothriasis can be a long-lasting infection (decades). Most infections are asymptomatic. Manifestations may include abdominal discomfort, diarrhea, vomiting, and weight loss. Vitamin B12 deficiency with pernicious anemia may occur. Massive infections may result in intestinal obstruction, appendicitis . Migration of proglottids can cause cholecystitis or cholangitis. 02/14/21 Laboratory Diagnosis • Microscopic identification of eggs in the stool is the basis of specific diagnosis. • proglottids in feces. • Examination of proglotids passed in the stool is also of diagnostic value. • Anaemia in blood picture (Not true pernicious anemia) • (Megaloblastic Macrocytic Anemia) 02/14/21 Diagnostic findings Microscopy 02/14/21 measure 30 x 60 microns, and exhibit an operculum (this is the only cestode with an operculated egg). C 02/14/21 D Carmine-stained proglottids of D. latum, showing the rosette-shaped uterus G 02/14/21 H Treatment 1- Praziquantel 2- Niclosamide 3-Enema 4- Vitamin B12 Control Sanitary disposal of excreta and sewage Proper cooking/ freezing of fish Treat infected patients Health education 02/14/21 Spirometra )Tissue-Extraintestinal Cestodes(in Human (D.mansonoides-D.mansoni) Sparganosis is the term used to describe infection with the plerocercoid larvae (= spargana) of diphyllobothriid tapeworms of the genus Spirometra (Sparganum proliferum’ . D.mansonoides-D.mansoni or Spirometra mansni) Ocular sparganosis, Subcutaneous sparganosis,Brain sparganosis,…. A wide range of vertebrates, including humans, in which adult tapeworms will not develop, can also act as paratenic hosts. Human infection may occur in one of three ways: 02/14/21 1-By ingestion of cyclops containing procercoid larvae in drinking water from lake or open wells. 2-By application of the flesh of an infected frog to ulcers, sores and infected eyes; the plerocercoid is activated by warmth and enters the flesh. This is the most likely mode of infection in many parts of the world. 3-By ingestion of raw or undercooked meat of infected frogs, snakes, mammals or birds; the contained plerocercoids burrowing through the wall of the intestine 02/14/21 02/14/21 02/14/21 02/14/21 Diagnosis of Sparganosis 1.1.History: History:eating eatinghabit habit 2.2.Clinical Clinicalsigns: signs:nodules nodules 3.3.CBC: CBC:esosinophilia esosinophilia 4.4.Surgical Surgicalremove remove Treatment Treatment Surgical Surgicalremove remove Praziquantel, Praziquantel,Mebendazole,… Mebendazole,… 02/14/21 cirrus genital pore testes vagina uterus vas deferens vitellaria 1 mm vitelline duct ovary ootype Cyclops with procercoids of Spirometra sp. 02/14/21 Mature