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General Parasitology

General Parasitology

The following presentation is a general introduction to the field of parasitology, using roundworms as a specific example.

General Parasitology © 2021 by E. Nomi is licensed under CC BY-NC-SA 4.0

The University of Nomi

February 06, 2024
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  1. E. Nomi
    Parasitology
    - A brief introduction.
    Photo: medicine.wustl.edu
    E. Nomi, Dec. 2021

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  2. E. Nomi
    4 Infection Domains

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  3. E. Nomi
    4 Infection Domains
    - Bacteria
    Photo: “Tongue Bacteria, SEM” by Steve Gschmeissner, via fineartamerica.com
    Escherichia coli

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  4. E. Nomi
    4 Infection Domains
    - Bacteria
    - Viruses
    Photo: medicalnewstoday.com
    SARS-CoV-2 virus

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  5. E. Nomi
    4 Infection Domains
    - Bacteria
    - Viruses
    - Fungi
    Photo: “Aspergillus fumigatus as seen under a scanning electron microscope” by Koichi Makimura via theconversation.com
    Aspergillus fumigatus

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  6. E. Nomi
    4 Infection Domains
    - Bacteria
    - Viruses
    - Fungi
    - Parasites
    Photo: “Ancylostoma duodenale” by David Scharf via Science Source
    Ancylostoma duodenale

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  7. E. Nomi
    Q: Where could you pick up a parasite?
    Photos: campus.sg/wp-content; nairobileo.co.ke E. Nomi

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  8. E. Nomi
    Answer: Either location!
    Photos: campus.sg/wp-content; nairobileo.co.ke E. Nomi

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  9. E. Nomi
    Parasitology
    Myth: Parasites are a disease of poverty.
    Fact: While lack of resources, infrastructure and poor
    sanitation can increase rates of infection, parasites can
    be present anywhere there are animals. This includes
    industrialized nations.
    Photos: campus.sg/wp-content; nairobileo.co.ke E. Nomi

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  10. E. Nomi
    Parasites can
    spread by:
    -Direct contact
    - Air
    - Water
    - Soil
    - Contaminated food Scabies - Sarcoptes scabiei
    • Scabies infections affect >200 million people globally 1
    • Transmitted through skin contact
    • Mites burrow into top layer of the epidermis
    • Itching, raised blisters, secondary bacterial infection
    Photo: parasites.czu.cz Photo: sciencecodex.com
    E. Nomi

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  11. E. Nomi
    Parasites can
    spread by:
    - Direct contact
    -Air
    - Water
    - Soil
    - Contaminated food
    Photo: afro.who.int Photo: geneticist.tumblr.com
    Map: cdc.gov/malaria/about/distribution
    Malaria - Plasmodium
    • 241 million malaria cases, 627,000 deaths globally in 2020 2
    • Caused by several species of Plasmodium
    • Enters bloodstream via mosquito bite, infects red blood cells
    • Fever, headache, chills. If untreated, severe illness and death
    Transmission not
    known to occur
    Transmission occurs in
    some places
    Transmission occurs
    throughout
    E. Nomi

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  12. E. Nomi
    Parasites can
    spread by:
    - Direct contact
    - Air
    -Water
    - Soil
    - Contaminated food
    Giardiasis - Giardia intestinalis
    • Infects 280 million people per year, globally 3
    • Cysts transmitted in contaminated drinking water
    • Hatch in digestive system, attach to intestinal wall
    • Diarrhea, gas, cramping, foul-smelling, greasy stools
    Photo: Dr. Stan Erlandsen, USCDCP via Pixnio
    Photo: hyperoutdoor.com
    Photo: matadornetwork.com
    E. Nomi

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  13. E. Nomi
    Parasites can
    spread by:
    - Direct contact
    - Air
    - Water
    -Soil
    - Contaminated food
    Photo: medicine.wustl.edu
    Photo: atsdr.cdc.gov
    Photo: puppytoob.com
    Soil-Transmitted Helminth Infections
    •Variety of species infecting >1.5 billion people worldwide
    (24% of world population). More prevalent in tropical climates 4
    •Worms live in intestines, eggs pass in faeces and spread through soil
    •Most cause gastrointestinal disease, diarrhea and abdominal pain
    E. Nomi

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  14. E. Nomi
    Parasites can
    spread by:
    - Direct contact
    - Air
    - Water
    - Soil
    - Contaminated food Photo: theveganinsider.com
    Photo: E-Anjei via Getty Images Photo: Figure 1, Madi et al. 2013
    Photo: doctorsbeyondmedicine.com
    Foodborne Parasitic Disease
    • About 23.2 million cases and 45,927 deaths/year worldwide 5
    • Anisakis from raw fish
    • Tapeworm from unwashed contaminated fruits and vegetables
    E. Nomi

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  15. E. Nomi
    Perfect example of a parasite: the roundworm
    - Completely dependent on host to survive and reproduce
    - Distinct internal and external life stages
    - Causes significant disease
    Photo: parasitecleanse.net E. Nomi

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  16. E. Nomi
    • A common soil-transmitted helminth infection and foodborne disease
    - Worm eggs ingested from contaminated soil or unwashed fruits and vegetables
    - Eggs persist in environment for several weeks to several years 6
    • Life cycle requires host for maturation stage
    - Ingested eggs hatch into larvae in digestive tract
    - Larvae can migrate to the liver, lungs, and other organs
    - Adults return to digestive tract to lay eggs
    • One of the most common types of parasitic infections 6
    - Infect dogs, cats, humans, pigs, and other animals
    Roundworms
    Photo: parasitecleanse.net E. Nomi

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  17. E. Nomi
    Photos: parasitecleanse.net, onlinewebfonts.com
    Two of the most common roundworm infections: 7,8
    • Ascariasis
    - Caused by Ascaris spp.
    • Toxocariasis
    - Caused by Toxocara spp.
    Roundworms
    E. Nomi

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  18. E. Nomi
    Ascariasis
    • Zoonotic infection:
    - Pig roundworm (Ascaris suum)
    - Infects humans, incidence unknown 9
    - OR -
    • Human-to-human infection:
    - Human roundworm
    (Ascaris lumbricoides)
    - Infects 807 million–1.2 billion people world-
    wide 10
    Photos: link.vet.ed.ac.uk, thenounproject.com E. Nomi

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  19. E. Nomi
    Ascariasis
    • Symptoms:
    - Many carriers are asymptomatic 10
    - Abdominal pain, diarrhea
    - Respiratory symptoms if larvae migrate to lungs
    • Treatment:
    - Albendazole, mebendazole or ivermectin
    - Surgical removal of worms
    Photos: foxnews.com, istockphoto.com, flickr.com E. Nomi

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  20. E. Nomi
    Toxocariasis
    • Zoonotic infection caused by:
    - Dog roundworm
    (Toxocara canis)
    - Cat roundworm
    (Toxocara cati)
    • Larvae can migrate through intestines
    to liver, lungs, central nervous
    system, eyes, or other tissues
    Photos: onlinewebfonts.com, nytimes.com, ilbaccarodublin.com E. Nomi

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  21. E. Nomi
    Toxocariasis
    Photos: parasitophilia.blogspot.com, imagebank.asrs.org, cdc.gov/dpdx/toxocariasis
    • Symptoms:
    - Many carriers are asymptomatic 11
    - Cough, inflammation, rash, fever
    - Tissue damage to organs
    • Treatment:
    - Albendazole
    - Mebendazole
    E. Nomi

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  22. E. Nomi
    Photos: chegg.com, “Toxocara Canis” by Sinclair Stammers/science via fineartamerica.com
    Worm stage
    E. Nomi

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  23. E. Nomi
    Photos: chegg.com, “Toxocara Canis” by Sinclair Stammers/science via fineartamerica.com
    Egg stage
    E. Nomi

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  24. E. Nomi
    Photos: stickerbrand.com, grainsduquebec.ca, bp.blogspot.com,
    Life Cycle of Roundworms

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  25. E. Nomi
    Photos: stickerbrand.com, grainsduquebec.ca, bp.blogspot.com,
    Life Cycle of Roundworms
    Inter
    nal

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  26. E. Nomi
    Photos: stickerbrand.com, sobretumascota.blogspot.com
    Life Cycle of Roundworms
    Exter
    nal

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  27. E. Nomi
    Photos: stickerbrand.com, bp.blogspot.com, sobretumascota.blogspot.com, srpplayground.com
    Life Cycle of Roundworms
    Exter
    nal
    Eggs in soil
    Inter
    nal

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  28. E. Nomi
    Photos: stickerbrand.com, bp.blogspot.com, sobretumascota.blogspot.com
    Life Cycle of Roundworms
    Exter
    nal
    Fertilized eggs
    mature
    Inter
    nal

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  29. E. Nomi
    Photos: stickerbrand.com, bp.blogspot.com, sobretumascota.blogspot.com, simplemost.com, atsdr.cdc.gov
    Life Cycle of Roundworms
    Eggs ingested,
    hatch
    Inter
    nal
    Exter
    nal

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  30. E. Nomi
    Photos: stickerbrand.com, bp.blogspot.com, sobretumascota.blogspot.com, istockphoto.com
    Life Cycle of Roundworms
    Inter
    nal
    Exter
    nal
    Larvae can migrate
    to different parts of
    the body

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  31. E. Nomi
    Photos: stickerbrand.com, bp.blogspot.com, sobretumascota.blogspot.com, grainsduquebec.ca, caribbeanmedicaljournal.org, cram.com
    Life Cycle of Roundworms
    Inter
    nal
    Exter
    nal
    Mature worms in
    intestines lay eggs

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  32. E. Nomi
    Photos: stickerbrand.com, grainsduquebec.ca, bp.blogspot.com, sobretumascota.blogspot.com, dogster.com, “Roundworm In Dog Feces” by John Daniels via fineartamerica.com
    Life Cycle of Roundworms
    Eggs passed back
    into soil
    Exter
    nal
    Inter
    nal

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  33. E. Nomi
    Photos: stickerbrand.com, grainsduquebec.ca, bp.blogspot.com, sobretumascota.blogspot.com
    Life Cycle of Roundworms
    Inter
    nal
    Exter
    nal

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  34. E. Nomi
    • Wash hands after being outdoors or handling animals
    • Wash fruits and vegetables before eating
    • Regularly deworm your pets, keep animal pens clean
    Prevention
    Photos: dogsaholic, clipartkey.com, dreamstime.com

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  35. E. Nomi
    Photo: sciencebusiness.net, mebendazole_ivermectinsales, albendazole_salvavidaspharma
    WHO recommended medicines:
    • Mebendazole (500 mg)
    Anthelmintic Drugs
    • Albendazole (400 mg)
    • The WHO recommends periodic deworming treatment to all at-risk people living
    in endemic areas, with or without a diagnosis.

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  36. E. Nomi
    Growing Drug Resistance
    • Some worms survive treatment
    • The survivors breed
    • Drug resistance genes spread through population
    • Drug stops working
    = Resistant
    = Susceptible

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  37. E. Nomi
    Why Does Parasitology Matter?
    • Parasites can cause diseases
    • Parasites can be found almost everywhere
    • The diseases they cause are getting worse
    - Warming climate causing parasites to spread further 12
    - Growing resistance to drug treatments worldwide 13
    Photo: theveganinsider.com

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  38. E. Nomi
    E. Nomi

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  39. E. Nomi
    E. Nomi

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  40. E. Nomi
    Thank You!
    Photo: medicine.wustl.edu

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  41. E. Nomi
    References
    1. The World Health Organization. (2020, August 16). Scabies. Retrieved December 13, 2021, from https://www.who.int/news-room/fact-sheets/detail/scabies
    2. World Health Organization. (2021). World malaria report 2021. Retrieved December 13, 2021, from https://apps.who.int/iris/handle/10665/350147
    3. Laishram, S., Kang, G., & Ajjampur, S. S. R. (2012). Giardiasis: A review on assemblage distribution and epidemiology in India. Indian Journal of Gastroenterology, 31(1), 3–12. https://doi.org/10.1007/s12664-012-0161-9
    4. World Health Organization. (2020, March 02). Soil-transmitted helminth infections. Retrieved December 13, 2021, from https://www.who.int/news-room/fact-sheets/detail/soil-transmitted-helminth-infections
    5. Torgerson, P. R., Devleesschauwer, B., Praet, N., Speybroeck, N., Willingham, A. L., Kasuga, F., Rokni, M. B., Zhou, X. N., Fèvre, E. M., Sripa, B., Gargouri, N., Fürst, T., Budke, C. M., Carabin, H., Kirk, M. D., Angulo, F. J.,
    Havelaar, A., & de Silva, N. (2015). World Health Organization Estimates of the Global and Regional Disease Burden of 11 Foodborne Parasitic Diseases, 2010: A Data Synthesis. PLoS medicine, 12(12), e1001920.
    https://doi.org/10.1371/journal.pmed.1001920
    6. The Centers for Disease Control and Prevention. (2021). What Every Pet Owner Should Know About Roundworms & Hookworms [Fact sheet]. U.S. Department of Health & Human Services.
    https://www.cdc.gov/parasites/resources/pdf/roundworms_hookworms.pdf
    7. The Centers for Disease Control and Prevention. (2020, October 27). Parasites - Soil-transmitted helminths. Retrieved December 27, 2021, from https://www.cdc.gov/parasites/sth/index.html
    8. The Centers for Disease Control and Prevention. (2021). Neglected Parasitic Infections in the United States Toxocariasis [Fact sheet]. U.S. Department of Health & Human Services.
    https://www.cdc.gov/parasites/resources/pdf/npi_toxocariasis.pdf
    9. Silva, T., Barbosa, F. S., Magalhães, L., Gazzinelli-Guimarães, P. H., Dos Santos, A. C., Nogueira, D. S., Resende, N. M., Amorim, C. C., Gazzinelli-Guimarães, A. C., Viana, A. G., Geiger, S. M., Bartholomeu, D. C., Fujiwara, R.
    T., & Bueno, L. L. (2021). Unraveling Ascaris suum experimental infection in humans. Microbes and infection, 23(8), 104836. https://doi.org/10.1016/j.micinf.2021.104836
    10. The Centers for Disease Control and Prevention. (2020, November 23). Parasites - Ascariasis. Retrieved December 7, 2021, from https://www.cdc.gov/parasites/ascariasis/
    11. The Centers for Disease Control and Prevention. (2021). Neglected Parasitic Infections in the United States Toxocariasis [Fact sheet]. U.S. Department of Health & Human Services.
    https://www.cdc.gov/parasites/toxocariasis/resources/toxocariasis_provider_fact_sheet.pdf
    12. Pozio, E. (2019). How globalization and climate change could affect foodborne parasites. Experimental Parasitology, 107807. https://doi.org/10.1016/j.exppara.2019.107807
    13. Sierra, J. M., Fusté, E., Rabanal, F., Vinuesa, T., & Viñas, M. (2017). An overview of antimicrobial peptides and the latest advances in their development. Expert Opinion on Biological Therapy, 17(6), 663–676.
    https://doi.org/10.1080/14712598.2017.1315402
    14. Murdaca, G., Greco, M., Borro, M., & Gangemi, S. (2021). Hygiene hypothesis and autoimmune diseases: A narrative review of clinical evidences and mechanisms. Autoimmunity Reviews, 20(7), 102845.
    https://doi.org/10.1016/j.autrev.2021.102845
    15. Wang, M., Wu, L., Weng, R., Zheng, W., Wu, Z., & Lv, Z. (2017). Therapeutic potential of helminths in autoimmune diseases: helminth-derived immune-regulators and immune balance. Parasitology Research, 116(8), 2065–2074.
    https://doi.org/10.1007/s00436-017-5544-5

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  42. E. Nomi
    Other References
    Belleza, Marianne. (2021, February 11). Roundworms (Ascariasis). Nurselabs. Retrieved December 7, 2021, from https://nurseslabs.com/roundworms-ascariasis/
    Fialho, P. M., & Corrêa, C. R. (2016). A Systematic Review of Toxocariasis: A Neglected But High-Prevalence Disease in Brazil. The American journal of tropical medicine and hygiene, 94(6), 1193–1199.
    https://doi.org/10.4269/ajtmh.15-0733
    Kenyon, F., Hutchings, F., Morgan-Davies, C., van Dijk, J., & Bartley, D. J. (2017). Worm Control in Livestock: Bringing Science to the Field. Trends in Parasitology, 33(9), 669–677. https://doi.org/10.1016/j.pt.2017.05.008
    L’Ollivier, C., & Piarroux, R. (2013). Diagnosis of human nematode infections. Expert Review of Anti-Infective Therapy, 11(12), 1363–1376. https://doi.org/10.1586/14787210.2013.851001
    Moxon, C. A., Gibbins, M. P., McGuinness, D., Milner, D. A., & Marti, M. (2019). New Insights into Malaria Pathogenesis. Annual Review of Pathology: Mechanisms of Disease, 15(1). https://doi.org/10.1146/annurev-
    pathmechdis-012419-032640
    Nazer, H. (2018, October 1). Giardiasis. Retrieved December 13, 2021, from https://www.who.int/news-room/fact-sheets/detail/scabies
    Pearson, Richard D. (2020, September). Toxocariasis. SD Manual. Retrieved December 21, 2021, from https://www.msdmanuals.com/professional/infectious-diseases/nematodes-roundworms/toxocariasis
    Stepek, G., Buttle, D. J., Duce, I. R., & Behnke, J. M. (2006). Human gastrointestinal nematode infections: are new control methods required?. International journal of experimental pathology, 87(5), 325–341.
    https://doi.org/10.1111/j.1365-2613.2006.00495.x
    The Centers for Disease Control and Prevention. (2013). Neglected Parasitic Infections in the United States Toxocariasis [Fact sheet]. U.S. Department of Health & Human Services.
    https://www.cdc.gov/parasites/toxocariasis/resources/toxocariasis_fact_sheet.pdf
    The Centers for Disease Control and Prevention. (2020, November 23). Parasites - Ascariasis. Retrieved December 7, 2021, from https://www.cdc.gov/parasites/ascariasis/gen_info/faqs.html
    The Centers for Disease Control and Prevention. (2021, February 26). Parasites - Giardia, Illness and Symptoms. Retrieved December 20, 2021, from https://www.cdc.gov/parasites/giardia/illness.html
    The World Health Organization. (2021, December 6). Malaria. Retrieved December 14, 2021, from https://www.who.int/news-room/fact-sheets/detail/malaria

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