NRS413 Microbiology and Parasitology in Nursing HS260 PDF 2024/2025

10/21/2024 Centre for Nursing Studies HS260 HS260 NRS413 Microbiology and Parasitology in Nursing NRS413_HS260_2024/2025...

10/21/2024 Centre for Nursing Studies HS260 HS260 NRS413 Microbiology and Parasitology in Nursing NRS413_HS260_2024/2025 1 1 Centre for Nursing Studies HS260 INTRODUCTION TO THE COURSE NRS413_HS260_2024/2025 2 2 1  10/21/2024 Centre for Nursing Studies HS260 COURSE INFORMATION PROGRAMME : Bachelor in Nursing (Honours) - HS260 COURSE CODE : NRS413 COURSE NAME : Microbiology and Parasitology in Nursing CREDIT UNIT : 3 Credit SLT : 120 hours PART :1 THEORY : HS2601A: 1.5 hours (Wednesday) + 1.5 hours (Thursday) HS2601B: 1.5 hours (Tuesday) + 1.5 hours (Wednesday) NRS413_HS260_2024/2025 3 3 Centre for Nursing Studies HS260 COURSE DESCRIPTION This course is designed to assist students in the study of important microorganisms and parasites. It explains the physiology and pathogenic properties of bacteria, fungi, and viruses as an introduction to disease causation, their biology, the infections they cause, host response to these infections and their mode of transmission, prevention, treatment, and nursing responsibilities. NRS413_HS260_2024/2025 4 4 2  10/21/2024 Centre for Nursing Studies HS260 COURSE OUTCOME Upon completion of this course, students should be able to: 1. Apply the concepts and principles of microbiology and parasitology in the care of clients across the life span (PLO1, C3). 2. Compare the basic features of bacteria, viruses, fungi, and parasites (PLO2, C4). 3. Classify the mode of transmission of infectious diseases affecting the human system and the measurement to prevent and control the spread of infectious diseases through a group work (PLO4, A4). NRS413_HS260_2024/2025 5 5 Centre for Nursing Studies HS260 SESSION PLAN NRS413_HS260_2024/2025 6 6 3  10/21/2024 Centre for Nursing Studies HS260 Week Date Lecture Remarks Introduction to the course Introduction to parasitology 1 9-10-24 Definition Parasitism  Pathogenesis 2 16-10-24  Application of parasitology in the nursing field Classification and description of parasites (Description of Life Cycle, Mode of Infection, Infective stage, Diagnostic stage, 3 23-10-24 treatment) Protozoa (Amoeba) 4 30-10-24  Protozoa (Flagellate, Coccidia) 5 6-11-24  Helminths (Trematodes) 6 13-11-24  Helminths (Cestodes) SEMESTER BREAK (18 – 24 November 2024) NRS413_HS260_2024/2025 7 7 Centre for Nursing Studies HS260 Week Date Lecture Remarks 7 27-11-24 Helminths (Nematodes) 8 4-12-24  Helminths (Filariae) 9 11-12-24  Arthropoda (Ticks, Lice) 10 18-12-24  Arthropoda (Mosquitoes) SEMESTER BREAK (23 - 29 Disember 2024) NRS413_HS260_2024/2025 8 8 4  10/21/2024 Centre for Nursing Studies HS260 Week Date Lecture Remarks Control and prevent the spread of infectious diseases. 1-01-25 11 (PH)  Sterilization and disinfection – chemical and physical agents  Specimen collection and handling  Management of communicable diseases 12 8-01-25  Prevention of Hospital-Acquired (Nosocomial) Infections Microbial Pathogenicity and Epidemiology  Reservoirs of infectious agents 13 15-01-25  Modes of disease transmission  Control of epidemic disease Presentation Control and prevent the spread of infectious diseases. To assess nursing students' interpersonal skills (communication, 14 22-01-25 teamwork, leadership, and collaboration)  Modes of transmission of specific parasitic diseases and identify measures to prevent and control their spread. REVISON WEEK (27 Januari – 2 Februari 2025) NRS413_HS260_2024/2025 9 9 Centre for Nursing Studies HS260 WRITTEN ASSIGMENT (Critical Thinking ) Objective: To evaluate students' ability to PLO2 (20%) critically analyze and compare the fundamental Final Assessment characteristics of bacteria, viruses, fungi, and parasites. PLO1 (60%) (Knowledge ) Deadline: Week 7 FINAL EXAMINATION MCQ 40 Questions Continuous Assessment (40%) ASSESSMENT 2 Essay (MEQ) 60 Marks GROUP PRESENTATION Date : Exam week (Interpersonal skills ) (PROJECT) PLO4 (20%) Objective: To assess the students' interpersonal skills (communication, teamwork, collaboration) while they explore different aspects of infection control and prevention. Date : Week 14 NRS413_HS260_2024/2025 10 10 5  10/21/2024 Centre for Nursing Studies HS260 RESOURCE PAGE Recommended Text Engelkirk, P. G., Duben-Engelkirk, J., & Fader, R. C. (2020). Burton’s microbiology for the health sciences, enhanced edition (11th ed.). Jones and Bartlett. Murray, P. R. (2017). Basic Medical Microbiology. Elsevier - Health Sciences Division. References Patrick R. Murray, Ken S. Rosenthal, Michael A. Pfaller, Medical Microbiology, Ninth Edition, Elsevier, 2021, URL: https://www- clinicalkey-com.uitm.idm.oclc.org/#!/browse/book/3-s2.0-C20180000924 Michael R. Barer, Will Irving, Andrew Swann, Nelun Perera, Medical Microbiology A Guide To Microbial Infections: Pathogenesis, Immunity, Laboratory Investigation And Control, Elsevier, 2019, URL: https://www-clinicalkey- com.uitm.idm.oclc.org/#!/browse/book/3-s2.0-C20150065212 Murray, P. R., Rosenthal, K. S., & Pfaller, M. A. (2020). Medical Microbiology (9th ed.). Elsevier - Health Sciences Division. VanMeter, K. C., & Hubert, R. J. (2021). Microbiology for the healthcare professional (3rd ed.). Mosby. NRS413_HS260_2024/2025 11 11 NRS413_HS260_2024/2025 12 12 6  10/21/2024 NRS413_HS260_2024/2025 13 13 Centre for Nursing Studies HS260 PARASITOLOGY NRS413_HS260_2024/2025 14 14 7  10/21/2024 Centre for Nursing Studies HS260 INTRODUCTION What do you think parasitology is? Branch of biology & medicine that studies parasites, their hosts, and the relationship between them. Parasitology explores how parasites impact human health & helping to develop treatments & control methods for parasitic infestations. 15 NRS413_HS260_2024/2025 15 Centre for Nursing Studies HS260 INTRODUCTION Can you name a few diseases caused by parasites? 16 NRS413_HS260_2024/2025 16 8  10/21/2024 Centre for Nursing Studies HS260 INTRODUCTION Can you name a few diseases caused by parasites? Toxoplasmosis Caused by Toxoplasma gondii -transmitted to humans through contact with cat feces or eating undercooked meat. Dangerous for pregnant women (Risk of miscarriage, stillbirth) & immunocompromised individuals (organ damage). Soil-Transmitted Helminths (Hookworm) barefoot on contaminated soil. cause anemia & malnutrition, especially in children. 17 NRS413_HS260_2024/2025 17 Centre for Nursing Studies HS260 INTRODUCTION Can you name a few diseases caused by parasites? Malaria caused by Plasmodium parasites (bite of infected Anopheles mosquitoes) can cause fever, chills, > if untreated, serious complications (Organ damage, anemia). Lymphatic Filariasis (Elephantiasis)- transmitted by mosquitoes Caused by microscopic worms like Wuchereria bancrofti can lead to severe swelling of the limbs. 18 NRS413_HS260_2024/2025 18 9  10/21/2024 Centre for Nursing Studies HS260 LEARNING OUTCOME At the end of this lesson student will be able to: 1. define the common term used in medical parasitology 2. explain host - parasite relationship. 3. explain the general life cycle of parasite. 4. explain briefly host immunity & immune –evasion mechanism by parasites. 5. describe classification of medically important of parasites. 6. apply the knowledge of parasitology to nursing practice, particularly in the prevention, diagnosis, and management of parasitic diseases. NRS413_HS260_2024/2025 19 19 Centre for Nursing Studies HS260 INTRODUCTION DEFINITION Medical Parasitology (Greece: Para=besides, Sitos=food) Parasitos “Somebody who eats food from another’s table” is a science that deals with organism living in the human body (the host) and the medical significance of this host –parasites relationship (effects they have on health). Parasite An organism which derives its nourishment at the cost of another organism (host) in or on which it lives is called a parasite. Host is an organism (in this case, the human body) that supports the parasite by providing it with food and shelter NRS413_HS260_2024/2025 20 20 10  10/21/2024 Centre for Nursing Studies HS260 Medical Parasitology Medical protozoology Medical helminthology Medical Arthropodology (Single Cell Animal) (Multicellular) (True" or "inherent" ) Protozoa Helminthic Arthropods (insects & E.g: Malaria, amoebiasis & Nematodes (Roundworms) arachnids) giardiasis Trematodes (Flukes) Mite, ticks, & fleas Cestodes (Tapeworms) NRS413_HS260_2024/2025 21 21 Centre for Nursing Studies HS260 Medical protozoology (Single Cell Animal) Protozoa Characteristics: Single-celled; anaerobic: Protozoa are unicellular organisms that can live without oxygen Asexual, sexual reproduction: Can reproduce through both asexual methods (like binary fission) & sexual methods (such as conjugation) Varied life cycles & stages: Trophozoites: Active, feeding stage of protozoa Cysts/Oocysts: Dormant (resting), protective stages that help protozoa survive harsh conditions & aid in transmission between hosts Intra & extracellular parasites: Can live inside or outside host cells, depending on the species. Some require multiple hosts: Some protozoan parasites need more than one host to complete their life cycle Motile> can move, using specialized structures. NRS413_HS260_2024/2025 22 22 11  10/21/2024 Centre for Nursing Studies HS260 Medical protozoology (Single Cell Animal) Protozoa Categorized based on their structures & modes of movement. Amoeboid protozoans Use one or more whip-like Ciliates have hair-like Lack movement structures like move using pseudopods structures called flagella for structures called cilia that help flagella or cilia in their mature (temporary projections of movement. in movement & feeding. forms. their cytoplasm). Have distinct shapes & Typically have 2 types of nuclei: Use a unique form of movement Engulf food by a process structures, including one or -macronucleus (larger, for called gliding motility. called phagocytosis. more nuclei. regular cellular function) & - micronucleus (smaller, for Have specialized organelles reproduction). called the apical complex that help in invading host cells. NRS413_HS260_2024/2025 23 23 Centre for Nursing Studies HS260 Medical helminthology (Multicellular) Classified under the kingdom Animalia Helminthic Characteristics: Multicellular - made up of many cells Adults are mostly anaerobic (do not require oxygen for survival). Can be hermaphroditic (having both male & female reproductive organs) or have separate sexes. Have muscular motility > can move around. Helminths can grow quite large. NRS413_HS260_2024/2025 24 24 12  10/21/2024 Centre for Nursing Studies HS260 Medical helminthology (Multicellular) Classified under the kingdom Animalia Helminthic Nematodes (Roundworms) Cestodes (Tapeworms) Trematodes (Flukes) Example: Trichinella. Example: Echinococcus. Example: Paragonimus & Schistosoma. Have a round, cylindrical body. Flat & segmented. Flat, leaf-shaped bodies Features include a mouth at one end & an anus Have suckers to attach to the host’s Flukes have suckers for attachment. at the other, covered by a cuticle (tough and intestines. Paragonimus is hermaphroditic. protects them from their environment) Typically hermaphroditic. Schistosoma has separate sexes (male Many nematodes have separate sexes and female worms are distinct). NRS413_HS260_2024/2025 25 25 Centre for Nursing Studies HS260 Medical Arthropodology (True" or "inherent" ) Classified under the kingdom Animalia Arthropods (insects & arachnids) Characteristics: True parasites: Arthropods like mites & lice live on a host (like humans) & take advantage of the host for food (often blood or skin), causing irritation and diseases. Segmented bodies: Their bodies are divided into different sections. Hard exoskeleton: This provides them with protection and support. Jointed appendages: Their legs & other body parts can move because they are connected with joints. Divided into 2 main groups: Chelicerata (arachnids):-mites. Insecta: - lice. NRS413_HS260_2024/2025 26 26 13  10/21/2024 Centre for Nursing Studies HS260 Medical Arthropodology (True" or "inherent" ) Classified under the kingdom Animalia Arthropods (insects & arachnids) Structure: small, wingless insects with 6 legs, each ending in Structure: small, spider-like creatures with 8 legs & claws that help them cling to hair or skin. bristle-like hairs called setae. Lifestyle: obligate parasites > must live on a host to survive > Disease: Sarcoptes scabiei causes scabies (mites Feed on blood from the skin. burrow into the skin to lay eggs, causing intense Disease: cause head lice, body lice, or pubic lice itching & rash) infestations. NRS413_HS260_2024/2025 27 27 NRS413_HS260_2024/2025 28 28 14  10/21/2024 Centre for Nursing Studies HS260 NRS413_HS260_2024/2025 29 29 Centre for Nursing Studies HS260 TYPES OF ORGANISM RELATIONSHIPS Symbiosis Symbiosis refers to a close & long-term interaction between 2 organisms of different species. Each organism in this relationship is called a symbiont. The nature of the relationship can vary, resulting in different types of symbiotic interactions. 3 main types of symbiotic: Mutualism both the host and the parasite benefit from the relationship. Permanent association between two different organisms that life apart is impossible (one cannot survive in the absence of the other). The mutual's are metabolically dependent on one another. e.g- is the relationship between certain species of flagellated protozoa living in the gut of termites. Protozoa acquire their nutrients from termites. In return, they synthesize and secrete cellulases; for the termites. NRS413_HS260_2024/2025 30 30 15  10/21/2024 Centre for Nursing Studies SYMBIOTIC INTERACTIONS HS260 TYPES OF ORGANISM RELATIONSHIPS Commensalism Close relationship between two different organisms from which one benefits and the other neither benefits nor suffers. E.g. E. coli and man. Parasitism is a biological relationship where one organism (the parasite) benefits at the expense of another organism (the host), often causing harm to the host. Parasite gets its nutrients, shelter, or reproductive resources from the host. e.g.- Tapeworms in the intestines of humans or animals. The tapeworms absorb nutrients from the host’s food, benefiting themselves, but they deprive the host of essential nutrients, potentially causing malnutrition or other health issues. NRS413_HS260_2024/2025 31 31 Centre for Nursing Studies SYMBIOTIC INTERACTIONS HS260 SUMMARY OF INTERACTIONS NRS413_HS260_2024/2025 32 32 16  10/21/2024 Centre for Nursing Studies HS260 CLASSIFICATION OF PARASITES Parasite It is a small organism which lives in or on the host (larger organism). In parasitism, the parasite is the benefited partner which obtains nourishment and shelter (niche) from the host. The parasite harms the host & has a much higher reproductive capability compared to its host. NRS413_HS260_2024/2025 33 33 Centre for Nursing Studies CLASSIFICATION OF PARASITES HS260 Parasite can be typed according to Endoparasite Ectoparasite Parasite that lives inside the body of its Parasite that lives on the outside host surface of its host. May be just under the surface or deep E.g. Flea, leeches, ticks in the body E.g. Tapeworms, flukes, protozoan NRS413_HS260_2024/2025 34 34 17  10/21/2024 Centre for Nursing Studies CLASSIFICATION OF PARASITES HS260 Parasite can be typed according to Facultative Parasite Obligate Parasite A parasite that may be parasitic A parasite that is entirely upon another organism but can dependent upon a host for its exist independently. survival. E.g. Naegleria fowleri> primary amoebic E.g. Plasmodium spp. > Malaria meningoencephalitis NRS413_HS260_2024/2025 35 35 Centre for Nursing Studies CLASSIFICATION OF PARASITES HS260 Parasite can be typed according to Pathogenic parasites Non-Pathogenic Opportunistic parasites Parasites that have the potential Parasites that do not cause Parasites that can cause to cause disease. disease under normal diseases when the immune circumstances. system of the host is E.g: Entamoeba histolytica E.g: Endolimax nana: suppressed. causes amoebic dysentery commonly found in the intestines of e.g: Pneumocystis jirovecii leading to severe diarrhea, stomach humans. rarely causes disease with pain healthy immune systems. can cause a severe form of pneumonia > weakened immune systems (HIV/AIDS, cancer) NRS413_HS260_2024/2025 36 36 18  10/21/2024 Centre for Nursing Studies CLASSIFICATION OF PARASITES HS260 Parasite can be typed according to Monoxenous parasites Heteroxenous parasites Requiring only a single host to complete the Those which require two or more hosts life cycle. to complete their life cycle (E.g. Plasmodium species). Have a direct life cycle Have an indirect life cycle (require an E.g. Ascaris lumbricoides intermediate host). NRS413_HS260_2024/2025 37 37 Centre for Nursing Studies CLASSIFICATION OF PARASITES HS260 Parasite can be typed according to Accidental parasite Erratic parasite when a parasite attacks an unnatural is one that wanders into an organ in host and survives. which it is not usually found. E.g. Hymenolepis diminuta (rat E.g. Entamoeba histolytica in the tapeworm). liver or lung of humans. NRS413_HS260_2024/2025 38 38 19  10/21/2024 Centre for Nursing Studies HS260 HOSTS Host: An organism that harbors and provides sustenance for another organism (the parasite). NRS413_HS260_2024/2025 39 39 Centre for Nursing Studies HOSTS HS260 Classification of Hosts INTERMEDIATE HOST Parasite spends short time period of its life cycle before exploiting a suitable host to become mature & reproduce sexually. Intermediate hosts are those that harbor asexual parasites until they move on to the definitive host for sexual reproduction. Also known as the secondary host. Figure 01: Human – An intermediate host of malaria parasite NRS413_HS260_2024/2025 40 40 20  10/21/2024 Centre for Nursing Studies HOSTS HS260 Classification of Hosts DEFINITIVE HOST Definitive hosts are organisms that harbor parasites until the completion of their life cycle. Definitive host or the final host is an organism in which a parasite becomes sexually matured. Also known as the primary host. Inside the definitive host, the parasite becomes an adult & reproduces sexually. Figure 02: Mosquito – A definitive host for malaria parasite For example: Definitive Host of Plasmodium= Female Anopheles mosquito Female Anopheles mosquito serves as the definitive host for the malaria parasite. NRS413_HS260_2024/2025 41 41 Centre for Nursing Studies HOSTS HS260 Human – An intermediate host of malaria parasite Definitive Host of Plasmodium= Female Anopheles mosquito The life cycle of Plasmodium spp. is one of the most fascinating displays of natural abilities in the biological world. Even after having so many life stages like sporozoites, schizonts, merozoites, hypnozoites (in some species), gametocytes (micro- and macro), zygotes, ookinetes, oocysts, back to sporozoites, the parasite doesn’t cause any harm to its “definitive host- the mosquito”!! While on the other side, according to WHO, the parasite killed nearly 409,000 of its intermediate hosts- “the humans” in 2019. Image Credit: CDC.gov NRS413_HS260_2024/2025 42 42 21  10/21/2024 Centre for Nursing Studies HOSTS HS260 NRS413_HS260_2024/2025 43 43 Centre for Nursing Studies HOSTS HS260 NRS413_HS260_2024/2025 44 44 22  10/21/2024 Centre for Nursing Studies HS260 VECTOR Vector: an organism (usually an arthropod) which transfers infective forms of a parasite from one host to the other. CLASSIFICATION OF VECTOR Mechanical Vectors Biological vectors (Parathenic ortransport) NRS413_HS260_2024/2025 45 45 Centre for Nursing Studies CLASSIFICATION OF VECTOR HS260 CLASSIFICATION OF VECTORS 1. Biological vectors: An arthropod in whose body the infecting organism develops or multiplies before becoming infective to the recipient individual. Types of Biological vectors: i. Propagative – multiplication of the pathogen without developmental change. E.g. Yersinia pestis in fleas. The number of pathogens increases inside the vector, but the pathogen stays in the same stage. ii. Cyclodevelopmental – developmental change without multiplication. E.g. Onchocerca volvulus in black flies. iii. Cyclopropagative – multiplication and developmental change of the pathogen. E.g. Plasmodium vivax in Anopheles mosquitoes. NRS413_HS260_2024/2025 46 46 23  10/21/2024 Centre for Nursing Studies CLASSIFICATION OF VECTOR HS260 2. Mechanical vector An arthropod that transmits the infective organisms from one host to another but is not essential to the life cycle of the parasite. No parasitic development or reproduction occurs. NRS413_HS260_2024/2025 47 47 Centre for Nursing Studies HS260 TRANSMISSION OF PARASITES 3 key links for parasitic disease transmission: 1. Source of infection 2. Mode of transmission 3. Susceptible host – a person or animal lacking sufficient resistance to a particular pathogenic agent to prevent disease if or when exposed. NRS413_HS260_2024/2025 48 48 24  10/21/2024 Centre for Nursing Studies TRANSMISSION OF PARASITES HS260 Source of infection The sources of exposure : 1. Contaminated soil: Soil polluted with human excreta is commonly responsible for exposure to infection with geohelminthes (like roundworms, hookworms, & whipworms). 2. Contaminated water: which may contain (drink or swimming) Cercarial stages of blood flukes > can cause schistosomiasis live in contaminated water and can penetrate human skin when someone swims or stands in that water. Viable cysts of Amoeba, flagellates etc... can survive in contaminated water Drink > can be infected & develop diseases like amoebiasis or giardiasis. Freshwater fishes which are sources for fish tapeworm & intestinal flukes eat raw or undercooked fish NRS413_HS260_2024/2025 49 49 Centre for Nursing Studies TRANSMISSION OF PARASITES HS260 Source of infection 3. Raw or insufficiently cooked meat of pork, beef, and fish Trichinella spiralis, Taenia species, Diphyllobothrium latum>cause tapeworm infections 4. Blood-sucking arthropods: Malaria – female Anopheles mosquito 5. Animals (domestic or wild animals harboring the parasite) Dogs - can carry the parasite Echinococcus granulosus> causes hydatid disease in humans. forms cysts in human organs (like the liver or lungs). People can get infected if they come into contact with dog feces or contaminated food. NRS413_HS260_2024/2025 50 50 25  10/21/2024 Centre for Nursing Studies TRANSMISSION OF PARASITES HS260 Source of infection 1. Human beings: A person, his/her clothing, bedding, or the immediate environment that he/she contaminated. Autoinfection: Autoinfection is the process where a host (in this case, a human) reinfects themselves without exposure to an external source or intermediary host. This means the parasite does not leave the body to infect another host but instead continues its life cycle within the same person. It is used to describe a host which is both intermediate and definitive without parasite transmission from other animals. Enterobius vermicularis >The eggs of the pinworm can hatch near the anus, and the larvae can migrate back into the intestines, causing continuous reinfection. NRS413_HS260_2024/2025 51 51 Centre for Nursing Studies HS260 MODES OF TRANSMISSION Direct mode of Transmission is the immediate transfer of infectious agents from an infected host or reservoir to an appropriate portal of entry. Classified as: I. Horizontal: Transmission is mainly affected through: Fecal-oral route: most intestinal parasites- (ingests food or water contaminated with feces containing the worm's eggs) Sexual intercourse-Trichomonas vaginalis > trichomoniasis Direct skin penetration-Hookworms (larvae can penetrate the skin when a person walks barefoot on contaminated soil) NRS413_HS260_2024/2025 52 52 26  10/21/2024 Centre for Nursing Studies MODES OF TRANSMISSION HS260 MODES OF TRANSMISSION II. Vertical: transmission of the parasite is from the mother to child through: Congenital / transplacental Transmammary (breast milk) NRS413_HS260_2024/2025 53 53 Centre for Nursing Studies MODES OF TRANSMISSION HS260 MODES OF TRANSMISSION Indirect Mode of Transmission is when the infectious agent is conveyed by an arthropod or contaminated inanimate objects. Intermediary, such as an insect (arthropod) or contaminated objects (inanimate objects). It occurs if the parasite (Arthropod): Has a complex life cycle-need different hosts to complete their life cycle. Requires biological vectors - Carry them from one host to another. One or more intermediate hosts-parasite must infect before it can reach its final host. Inanimate Objects: Giardia lamblia (causing giardiasis). can survive on surfaces like doorknobs or utensils. If someone touches a contaminated surface and then puts their hands in their mouth, they can ingest the parasite. NRS413_HS260_2024/2025 54 54 27  10/21/2024 Centre for Nursing Studies HS260 ROUTE OF TRANSMISSION It is a path in which the parasite enters the body of a susceptible host. Alimentary tract – ingestion of infective stage of parasites: In food, water, or hands contaminated with feces, E.g. E. histolytica, E. vermicularis, etc. In raw or undercooked meat, E.g. T. saginata, T. solium In raw or undercooked fish, crab, or water vegetation E.g. intestinal flukes NRS413_HS260_2024/2025 55 55 Centre for Nursing Studies ROUTE OF TRANSMISSION HS260 ROUTE OF TRANSMISSION Skin and mucous membranes Skin penetration when in contact with: Fecally polluted soil, E.g. hookworms Water containing infective stages of the parasite E.g. Cercaria of Schistosome species Through insect bite, E.g. Filarial worms, Plasmodium spp. NRS413_HS260_2024/2025 56 56 28  10/21/2024 Centre for Nursing Studies ROUTE OF TRANSMISSION HS260 Sexual Contact E.g. Trichomonas vaginalis Kissing E.g. Trichomonas gingivalis, T. tenax Transmammary E.g. Strongyloides stercoralis-nematode (roundworm) Respiratory tract – inhalation of contaminated air E.g. E. vermicularis Transplacental E.g. T. gondii NRS413_HS260_2024/2025 57 57 Centre for Nursing Studies HS260 GENERAL LIFE CYCLES OF PARASITES Parasite life cycles are extraordinarily diverse, complex, & fascinating. Some parasites require several distinct host species in a specific sequence to fully develop. Each host plays a role in a different developmental stage (egg, larva, nymph, adult). Example:- start as an egg in one host, develop into a larva in another host, then into an adult in a final host where it reproduces. Parasites have different ways of infecting hosts. Actively penetrate : hookworms burrowing through the skin Ingested : tapeworm larvae, which are eaten with contaminated food or water NRS413_HS260_2024/2025 58 58 29  10/21/2024 Centre for Nursing Studies HS260 GENERAL LIFE CYCLES OF PARASITES Example: Digenetic Trematodes (e.g., Liver Fluke) First Host (Snail): eggs are released in water, hatch into larvae (miracidia), & infect snails (intermediate host). Second Host: From the snail, the parasite transforms into another stage (cercaria), which encysts on aquatic plants or cercaria secondary hosts like fish. Final Host (Mammal): When mammals or humans eat contaminated plants or fish, aquatic mammals, they ingest the encysted larvae (metacercariae). In the mammal> matures into an adult in the liver & reproduces. NRS413_HS260_2024/2025 59 59 Centre for Nursing Studies HS260 GENERAL LIFE CYCLES OF PARASITES Parasitic & non-parasitic stages may occur in the cycle. essential for its survival, development, & reproduction. Phases: Growth & maturation development through various life stages (such as egg, larva, and adult). growing and maturing in one or more hosts, preparing for reproduction. Example: Ascaris lumbricoides: eggs hatch into larvae in the human intestine > larvae migrate to the lungs, (grow & mature) > After maturation, they are coughed up & swallowed back into the intestines, where they develop into adult worms. NRS413_HS260_2024/2025 60 60 30  10/21/2024 Centre for Nursing Studies HS260 GENERAL LIFE CYCLES OF PARASITES Reproduction (sexual & asexual) can reproduce sexually (involving the combination of genetic material from two ) or asexually (where a single organism produces offspring without fertilization). Both types of reproduction help maintain & increase the parasite population. Sexual reproduction: often occurs in the definitive host (the host where the parasite reaches adulthood). Asexual reproduction can occur in intermediate hosts> increasing numbers without needing another organism to reproduce. Example: Plasmodium falciparum NRS413_HS260_2024/2025 61 61 Centre for Nursing Studies HS260 GENERAL LIFE CYCLES OF PARASITES Transmission is the process by which the parasite moves from one host to another. Successful transmission ensures that the parasite can complete its life cycle & continue to spread. Example: For the liver fluke Eggs are released in the feces of the definitive host (e.g., sheep, birds or cattle) into water. Larvae (miracidia) infect a snail, where they grow & multiply. The next stage (cercaria) exits the snail & encysts on aquatic plants. Mammal eats these contaminated plants, the parasite reaches its final host, matures, & reproduces. NRS413_HS260_2024/2025 62 62 31  10/21/2024 Centre for Nursing Studies GENERAL LIFE CYCLES OF PARASITES HS260 SIMPLE OR DIRECT LIFE CYCLE (MONOXENOUS) Only one host is required to complete its cycle Parasite often spends most of its life, usually as an adult, & reproduces. Transmitted from one host to another through the air, by a fomite, or in contaminated food or water. NRS413_HS260_2024/2025 63 63 Centre for Nursing Studies GENERAL LIFE CYCLES OF PARASITES HS260 INDIRECT LIFE CYCLE (HETEROXENOUS) Requires two or more hosts to complete its life cycle Frequently, this may involve passing through a number of developmental stages & environments. NRS413_HS260_2024/2025 64 64 32  10/21/2024 NRS413_HS260_2024/2025 65 65 Centre for Nursing Studies HS260 Why we do study life cycles? A parasite’s life cycle consists of 2 common phases: 1-Internal Phase (Route Inside the Body) One phase involves the route a parasite follows inside the body. It involves how the parasite moves through organs or tissues, causing symptoms & disease. This information provides an understanding of the: Symptomatology & pathology where parasite travels & settles helps predict the symptoms & damage it may cause. Example: parasites in the liver or lungs cause different symptoms than those in the intestines. Method of diagnosis Location in the body helps > determine the best diagnostic method such as blood tests, stool samples, or imaging. NRS413_HS260_2024/2025 66 66 33  10/21/2024 Centre for Nursing Studies HS260 Why we do study life cycles? A parasite’s life cycle consists of 2 common phases: 1-Internal Phase (Route Inside the Body) Selection of appropriate medication Different stages of the parasite may require specific treatments. For instance, medications that target larvae may differ from those that target adult parasites Example: In schistosomiasis, the parasite (Schistosoma) enters the bloodstream, migrates to the liver, and finally lodges in the blood vessels of the intestines or bladder, causing organ damage. Symptoms include abdominal pain, blood in urine, or diarrhea. Diagnosis is through urine or stool samples, and antiparasitic drugs like praziquantel are used for treatment. NRS413_HS260_2024/2025 67 67 Centre for Nursing Studies Why we do study life cycles? HS260 2- External Phase (Route Outside the Body) How the parasite survives & moves between hosts outside of the body. How it is transmitted in the environment, its intermediate hosts, & how it spreads. Understanding this phase is essential for: Epidemiology: Knowing how the parasite spreads helps identify who is at risk & where outbreaks may occur. Prevention: Understanding the transmission route informs measures to prevent infection, such as sanitation, hygiene, or vector control. Control: Public health interventions, such as vaccination or vector control programs, are designed based on the parasite’s external phase. For malaria, the parasite is transmitted outside the body by mosquitoes. Understanding mosquito behavior (breeding in stagnant water) helps develop control measures like insecticide-treated bed nets, draining standing water, and using antimalarial drugs for prevention in high-risk areas. NRS413_HS260_2024/2025 68 68 34  10/21/2024 Centre for Nursing Studies HS260 APPLICATION OF PARASITOLOGY IN THE NURSING FIELD 1. Diagnosis & Treatment: Nurses need to recognize symptoms & manage treatments for parasitic infections. 2. Prevention: Educating patients on hygiene, proper food handling, & vector control to prevent parasitic diseases. 3. Public Health: Understanding how parasitic infections impact communities, particularly in tropical areas, helps nurses contribute to public health initiatives. 4. Infection Control: In clinical settings, nurses play a critical role in preventing the spread of parasitic diseases through proper infection control practices. NRS413_HS260_2024/2025 69 69 Centre for Nursing Studies HS260 REFERENCES Recommended Text Engelkirk, P. G., Duben-Engelkirk, J., & Fader, R. C. (2020). Burton’s microbiology for the health sciences, enhanced edition (11th ed.). Jones and Bartlett. Murray, P. R. (2017). Basic Medical Microbiology. Elsevier - Health Sciences Division. References Murray, P. R., Rosenthal, K. S., & Pfaller, M. A. (2020). Medical Microbiology (9th ed.). Elsevier - Health Sciences Division. Sastry, A. S., & Bhat, S. (2018). Essentials of medical parasitology (2nd ed.). Jaypee Brothers Medical. Stearns, J., & Surette, M. (2019). Microbiology For Dummies. John Wiley & Sons. Tortora, G. J., Funke, B. R., Case, C. L., Weber, D., & Bair, W. (2018). Microbiology: An Introduction, Books a la Carte Edition (13th ed.). Pearson. VanMeter, K. C., & Hubert, R. J. (2021). Microbiology for the healthcare professional (3rd ed.). Mosby. NRS413_HS260_2024/2025 70 70 35