WEEK 14

• BACHELOR OF SCIENCE IN NURSING

  Academic degree program
• MICROBIOLOGY AND PARASITOLOGY (MICP 211)


  Course name and code
• COURSE MODULE


  Organisational unit of a course
• COURSE UNIT


  Smaller organisational unit within a course module
• WEEK


  Time period within a course
• No. 12


  Week number
• 3 - FINAL PERIOD


  Period within the week
• 14


  Week number
• PROTOZOAN INFECTIONS


  Topic of the course unit
• Kingdom Protozoa are spherical, oval, or elongated single-celled eukaryotic creatures
• Taxonomy of organisms


  Primarily based on their locomotion organ
• Not all protozoa are parasitic. Acanthamoeba and Naegleria are facultative parasites that live independently
• Reproduction of protozoa


  Most do binary fission, sporozoans reproduce sexually and asexually, Morgony or schizogony produces asexual reproduction, Sexual recombination causes antigenic and genetic variation
• Diagnostics of protozoan infections


  Microscopic study of body fluids, tissue samples, or faeces, using special stains to show motile, feeding, dividing trophozoite or latent, non-motile cyst

  
• Pathogenic trophozoites


  Motile (with pseudopods or "false feet") and feed
• Except for Trichomonas vaginalis, most intestinal protozoan parasites have non-motile, infective cysts

  
• Entamoeba histolytica


  Causative agent of amebiasis, a disease that can be difficult to diagnose as other parasites can look similar, and infected people do not always become sick

  
• Entamoeba histolytica


  • Pathogenic Entamoeba species occur worldwide, frequently recovered from fresh water contaminated with human feces, occur in developing countries, risk groups include men who have sex with men, travelers, recent immigrants, immunocompromised persons, and institutionalized populations
• Treatment for amebiasis


  First line is metronidazole, alternative is tinidazole for both intestinal and extraintestinal amoebiasis

  
• Giardia lamblia (Giardia intestinalis)


  Microscopic parasite that causes giardiasis, a diarrheal illness, found in contaminated surfaces, soil, food, or water, has an outer shell that protects it from chlorine and allows it to survive outside the body
• Giardiasis


  • Affects the world, most common intestinal parasite disease in the US, causative agent is Diplomanadida flagellate Giardia duodenalis

  
• Trichomonas vaginalis


  Parasite that causes trichomoniasis, a prevalent STD, most infected persons are unaware of their infection

  
• Trichomonas vaginalis infection


  • In the US, prevalence is 2.1% among women aged 14-59 and 0.5% among men yr. 2013-2016, linked to increased poverty, poorer education, unmarried status, U.S. birthplace, lower age at first intercourse, more sex partners, and a history of chlamydia infection in the prior year
• Transmission of Trichomonas vaginalis

  Parasite passes from an infected person to an uninfected person during sex, the only way to avoid STDs is to not have vaginal, anal, or oral sex
• Balantidium coli


  Large ciliated protozoan, the only ciliate known to be capable of infecting humans, pig is the primary reservoir
• Balantidium coli infection


  • Main cause is pig feces-contaminated water, transmission via fecal-oral pathway, food handlers can spread epidemics, ingestion of polluted water leads to cyst excystation in the small intestines and trophozoites cause amoebiasis-like sores in the large intestine
• Treatment for Balantidium coli infection

  Involves two drugs - oxytetracyline and iodoquinol, metronidazole may also be used as alternative
• Acanthamoeba


  Small, free-living amoeba that can cause rare but severe eye, skin, and central nervous system infections, lives in water and soil globally, can be transferred through contact lenses, cuts, and skin sores, or by inhalation

  
• Naegleria


  Free-living protozoan similar to Acanthamoeba, lives in soil and contaminated water globally, can thrive in thermal spring water, Naegleria fowleri is the only amoeba possessing trophozoite, flagellate, and cyst forms, and is the world's pathogen

  
• Naegleria diseases


  Asymptomatic infection, Primary amoebic meningoencephalitis (PAM)

  
• Leishmania spp.


  Hemoflagellate parasites distributed worldwide, natural reservoirs include rodents, ant eaters, dogs, and cats, may be transmitted in a human-vector-human cycle

  
• Leishmania strains


  Leishmania donovani (visceral leishmaniasis), Leishmania tropica (cutaneous leishmaniasis), Leishmania basiliensis (monocutaneous leishmaniasis)
• Leishmaniasis


  Parasitic disease widespread in the tropics, subtropics, and southern Europe, classified as a neglected tropical disease, caused by parasites disseminated by phlebotomine sand flies' bites, can cause cutaneous (skin sores), visceral (affecting internal organs), and mucosal (rare) forms

  
• Leishmania donovani complex


  Causative agent of visceral leishmaniasis, a potentially fatal form affecting the spleen, liver, and bone marrow
• Leishmania tropica complex


  Causative agent of Old World Cutaneous Leishmaniasis, characterized by pus-filled ulcers that may heal on their own or form thick plaques with numerous nodules
• Trypanosoma spp.


  Hemoflagellates like Leishmania, but with trypomastigote diagnostic stage instead of amastigote

  
• Trypanosoma cruzi


  Parasitic protozoan that causes Chagas disease, transmitted by insect vectors in the Americas, discovered by Carlos Chagas in 1909

  
• Trypanosoma spp.


  Hemoflagellates, main difference from Leishmania is diagnostic stage - trypomastigote for trypanosomes

  
• Trypomastigotes


  • Bent, like the letters C, S, or U
  • Seen in the peripheral blood
• Trypanosoma cruzi


  Parasitic protozoan that causes Chagas disease