Parasitology Lecture Notes (2024/2025) - Sinai University PDF

Pharm D Program (2023/2024) 29 September 2024 www.su.edu.eg 1  Pharm PharmDDProgram Program (2024/2025) (2023/2024)...

Pharm D Program (2023/2024) 29 September 2024 www.su.edu.eg 1  Pharm PharmDDProgram Program (2024/2025) (2023/2024) (PM 906) Lecture No. (1) Introduction By Professor Yasser El Mohammadi 29 September 2024 www.su.edu.eg 2  Pharm PharmDDProgram Program (2024/2025) (2023/2024) Lecture’s Aim To allow the student to have a good knowledge about the basic principles of the science of parasitology. 29 September 2024 www.su.edu.eg 3  Pharm PharmDDProgram Program (2024/2025) (2023/2024) Lecture’s Competencies To enable the student to know about and understand the basic terminology of parasitology and the most important types of parasites and hosts. 29 September 2024 www.su.edu.eg 4  Pharm PharmDDProgram Program (2024/2025) (2023/2024) Lecture’s Contents - Introduction - Types of parasites - Types of hosts - Modes of transmission of parasitic diseases - Factors affecting parasitic diseases 29 September 2024 www.su.edu.eg 5 Parasitology (PM 906) 100 marks: - Final exam: 50 marks - Oral exam: 10 marks - Practical exam: 25 marks - Mid Term Exam x 10 marks - 2 Assignments x 2.5 marks Parasitology (PHM 2202) 100 marks: - Final exam: 40 marks - Practical exam: 25 marks - Mid Term Exam x 20 marks - Course Work x 10 marks - 2 Assignments x 2.5 marks Objectives of the course At the end of this course, the student should be able to: 1- State the meaning of commonly-used terms. 2- Discuss the classification of medically important human parasites. 3- Describe how parasitic infections can affect communities in poor countries and that knowledge of their life cycle is necessary for effective prevention and control. 4- Discuss the epidemiology, life cycle, clinical features, diagnosis and treatment of the important parasitic infections affecting humans.  Parasitology 1- Introduction: 1 Lecture 2- Helminthes: a- Trematodes: 2 Lectures b- Cestodes: 1 Lecture c- Nematodes: 3 Lectures 3- Protozoa: 5 Lectures  Parasitology Classification: The human parasites are classified within: 1. Protozoology = study of protozoa (primitive single cells). 2. Helminthology = study of helminthes (worms) including multicellular parasites with organs (also known as metazoa). 3. Entomology = study of arthropods (insects).  Basic Classification of Parasites of Medical Importance PROTOZOA “Single-celled Organisms” SARCO- MASTIGOPHORA CILIPHORA COCCIDIA Amoebae Ciliates Sporozoa Entamoeba histolyica Balantidium coli Plasmodium species Toxoplasma gondiia Flagellates Giardia lamblia Trichomonas vaginalis Haemoflagellates Trypansoma species Leishmania spiecies  HELMINTHES “Worms” PLATYHELMINTHES NEMATHELMINTHES “Flatworms” “Cylindrical Worms” CESTODA NEMATODA TREMATODA Round worms Tapeworms Flukes (digenetic) Taenia solium Ascaris lumbricoides Heterophyes heterophyes Enterobius vermicularis Taenia saginata Fasciola hepatica Strongyloides sterocoralis Echinococcus granulosus Schistosoma haematobium Trichuris tirchiura Hymenolepis nana Schistosoma mansoni Diphyllobothrium latum Ancylostoma duodenale Fasciolopsis buski Wuchereria bancrofti Brugia malayi Loa loa Onchocerca volvulus Dracunculus medinensis Trichinella spiralis  Parasitology I- Protozoa II- Helminths 1- Intestinal and C- Nematodes Urogenital Protozoa A- Trematodes(Flukes) (Round worms) A- Entamoeba 1- Fasciola hepatica 2- Fasciolopsis i- Instestinal histolytica buski Nematodes 1-Wuchereria bancrofti 3- Heterophyes B- Balantidium coli heterophyes 4- Shistosoma sp. 2-Ascaris lumbricoidges C- Giardia lamblia D- Trichomonas B- Cestodes 3- Hookworms vaginalis (Tape worms) 1- Taenia 4- Trichuris 2- Blood and Tissue saginata trichiura Protozoa 2- Taenia 5- Trichinella A- Hemoflagellates solium spiralis 3- Hymenolepis 1- Trypanosoma sp. Ii- Tissue Nematodes nana (Filariae) 4- Hymenolepis 1- Wuchereria 2- Leishmania sp. diminuta bancrofti 5- Echinococcus 2- Burgia malayi B- Sporozoa granulosus 3- Dracunculus 1- Plasmoduim sp. medinensis 2- Toxoplasma gondii 4- Loa loa 5- Onchocerca volvulus Entamoeba histolytica trophozoites Fasciola gigantica Fasciola hepatica Gravid proglottid Mature proglottid Taenia saginata Ascaris worm adult  Medical Importance of Parasites Humans are hosts to many species of parasites that are causative agents of major public health problems of the world. Recent estimates of prevalence of parasites in the world are: Ascaris 1.2 billion Hookworms 600-800 million Whipworms 600-800 million Filarial worms 190-200 million Malaria 200 million Schistosomes 200 million Amebiasis 50 million (100000 Deaths /yr) Taeniad tapeworms 50 million Clonorchis 20 million Chagas’ Disease 15 million These parasites cause untold suffering and death in the world today.  Parasite Diseases No. of people Deaths / yr infected Plasmodium Malaria 200 million 500,000- 600,000 Soil transmitted helminths: 2 billion 200,000 Roundworm (Ascaris) Pneumonitis, intestinal obstruction. Whipworm (Trichuris) Bloody diarrhoea, rectal prolapse. Coughing, wheezing, abdominal pain and anaemia. Hookworm (Ancylostoma and Necator) Schistosoma Renal tract and intestinal disease 200 million 15,000 Filariae Lymphatic filariasis and elephantiasis 120 million Not fatal but 40 million disfigured or incapacitated Trypanosoma cruzi Chagas disease (cardiovascular) 8 million 14,000 African trypanosomes African sleeping sickness 0.3 – 0.5 million 48,000 Leishmania Cutaneous, mucocutaneous and 9 million; 50,000 visceral leishmaniasis 1.5 million new cases/yr  Parasitology The science that deals with organisms (parasites) that live on or within other organisms (hosts). The association between two organisms may be one of the following: 1. Mutualism Mutual benefits is derived from the association. 2. Symbiosis Mutual benefit, and the two organisms can't live independently. 3. Commensalism One organism benefits (commensal) while the other (host) is unaffected. It may be also called a non- pathogenic parasite. 4. Parasitism One organism (parasite) lives at the expense of the other (host) which usually suffers from the association (pathogenic parasite). The parasite derives food & shelter from the host & causes a harmful effect to him. Types of parasites 1- Endoparasite: Lives within the body of the host (infection). 2- Ectoparasite: Lives on the outside of the body of the host (infestation). 3- Obligate parasite: Completely dependent upon its host and can't lead a free life. Consequently, it transfers directly from one host to another, e.g. Plasmodium sp., Trypanosoma sp. 4- Facultative parasite: : Capable of leading both a free living and a parasitic existence (in a host). 5- Temporary parasite: Free-living but seeks its host from time to time for food, e.g. Naegleria fowleri or Acanthamoeba sp. 6- Periodic parasite: Passes a definite part of its life cycle as a parasite. 7- Specific parasite: Occurs in one particular host, e.g. Trichomonas vaginalis.  Types of hosts 1- Final host or Definitive host: A host in which the parasite lives as sexually mature or adult stage with sexual (or asexual) reproduction. 2- Reservoir host: Animals that harbour the same species of parasites as man and constitute a source (store) of infection to him. 3- Intermediate host: A host in which a parasite lives as immature or larval stage with asexual reproduction (i.e. undergo transformation(s) from one stage to the other). The parasite spends a part of its life cycle inside this host i.e. undergo transformation(s) from one stage to the other. 4- Vector: An arthropod (insect) that carries a parasite to its host. a- Biological vector: The arthropod constitutes an integral part of the parasite life cycle (i.e. intermediate host for the parasite). b- Mechanical vector: The arthropod does not constitute an integral part of the parasite life cycle. The arthropod carries the parasite on or in its body (just passing through). Modes of transmission of parasitic diseases The infective stage of a parasite may be transmitted to a person in the following ways: 1- By ingesting the parasite in food, water, or from contaminated hands with faeces that contain the infective stage of the parasite as in case of Entamoeba histolytica, Giardia lamblia, Enterobius vermicularis and Trichuris trichiura. 2- By ingesting the parasite in raw or undercooked meat as in case of Taenia saginata, Taenia solium and Trichinella spiralis. 3- By ingesting the parasite in raw or undercooked fish, or water vegetation as in case of: Diphyllobothrium latum, Heterophyes heterophyes and Fasciolopsis buski. 4- By ingesting the parasite in water containing infected Cyclops as in case of Dracunculus medinensis. 5- By skin penetration by the parasite when in contact with faecally polluted soil as in case of Hookworms & Strongyloides stercoralis. 6- By skin penetration by the parasite when in contact with water containing the parasite as in case of Schistosoma species. 7- By an insect bite as in case of Wucheraria bancrofti, Loa loa, Brugia species, Onchocerca volvulus, Plasmodium species, Trypanosoma brucei, and Leishmania species. 8- By infected faeces from an insect being rubbed into the site of the insect bite as in case of Trypanosoma cruzi. 9- By sexual contact as in case of Trichomonas vaginalis. Foodborne parasitic diseases, caused an estimated 23.2 million cases and 6.64 million deaths annually (WHO, 2019)  Life cycle Life cycle is the sequence of morphological and environmental stages for survival, growth and reproduction of parasites. It may be: a. Direct life cycle: is the transmission from one definitive host to the other without the need of any intermediate host e.g. Trichomonas vaginalis. b. Indirect life cycle: is the transmission from one definitive host to the other using one or more intermediate hosts. Factors affecting parasitic diseases Not all parasitic infections cause diseases of clinical significance. Many factors control this process including: A. Parasitic factors: 1- Strain of the parasite. 2- Number of parasites. 3- Size of the parasite and site(s) occupied in the body. 4- Metabolic processes of the parasite. B. Host factors: 1- Age and level of natural immunity at the time of infection. 2- Immune responses to the infection. 3- Whether there is undernutrition or malnutrition. 4- Life style and work of the infected person. 5- Presence of co-existing disease or condition which reduces immune responses e.g. pregnancy. Effect of the parasite on the host The effect may be due to: 1- The parasite getting nourishment (food) from the host. 2- Mechanical effect leading to tissue destruction as a result of trauma, pressure, compression or obstruction, feeding on tissues or irritation of tissues leading to inflammatory or neoplastic reactions. 3- Toxic effects from toxins secreted or waste products excreted by the parasite, leading to poisoning or allergic reactions. 4- Secondary infection with other organisms as bacteria due to immunosuppression. The host reaction to the invading parasite may be: 1- Generalized (Systemic) in the form of fever, anaemia, eosinophilia, leucocytosis, leucopaenia, allergic reaction, weakness, etc. 2- Localized according to the tissue or organ affected, e.g. gastrointestinal disturbances (colic, dyspepsia, diarrhea, dysentery), itching, cough, ulceration, hepatomegaly, spleenomegaly, etc.  Pharm PharmDDProgram Program (2024/2025) (2023/2024) Lecture’s References - Diagnostic Medical Parasitology, (Elsevier Science Publishing Co. Inc.) by Garcia, LS & Bruckner, DA. - Atlas of Medical Helminthology and Protozoology, (E & S Livingstone) by Jeffrey & Leach 29 September 2024 www.su.edu.eg 35