Protozoan Parasites and Phylum Apicomplexa
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Questions and Answers

Which of the following are types of Babesia species?

  • Babesia microti
  • Babesia divergens
  • Babesia bovis
  • All of the above (correct)

    • Malaria is caused by foul emanations from marshy soil.

    True

    What primary vector is responsible for transmitting malaria?

    female Anopheles mosquito

    Malaria is identified as one of the three major infectious diseases threats along with HIV and _______.

    <p>Tuberculosis</p> Signup and view all the answers

    Match the following Plasmodium species with their characteristics:

    <p>Plasmodium falciparum = Responsible for 90% of malarial cases Plasmodium vivax = Responsible for 90% of malarial cases Plasmodium malariae = One of the types of Plasmodium Plasmodium ovale = One of the types of Plasmodium Plasmodium knowlesi = Usually not common in humans</p> Signup and view all the answers

    What does 'mal' mean in the context of malaria?

    <p>Bad</p> Signup and view all the answers

    The infective stage of malaria in humans is sporozoites.

    <p>True</p> Signup and view all the answers

    What are the intermediate hosts for Plasmodium species?

    <p>Man/Humans</p> Signup and view all the answers

    What happens during the sexual phase of a female anopheles mosquito?

    <p>Development of sporozoites</p> Signup and view all the answers

    What occurs after the fertilization of male and female gametocytes in the mosquito?

    <p>Formation of ookinetes</p> Signup and view all the answers

    What is the primary role of microgametes in the lifecycle of the malaria parasite within the mosquito?

    <p>To fertilize macrogametes</p> Signup and view all the answers

    What transformation occurs following the formation of zygotes in the mosquito?

    <p>Zygotes become elongated and active</p> Signup and view all the answers

    What is formed when oocysts in the mosquito ruptures?

    <p>Sporozoites</p> Signup and view all the answers

    Which type of gametocytes is described as female in the mosquito's lifecycle?

    <p>Macrogametocytes</p> Signup and view all the answers

    What is the process by which male gametocytes divide to become motile?

    <p>Exflagellation</p> Signup and view all the answers

    Where do the formed sporozoites travel after their release in the mosquito?

    <p>They penetrate the mosquito's salivary glands</p> Signup and view all the answers

    Which characteristic distinguishes Plasmodium falciparum from other malaria species?

    <p>Accole forms with crescentic masses</p> Signup and view all the answers

    What appearance is associated with male gametocytes of Plasmodium species?

    <p>Blunted edges</p> Signup and view all the answers

    What is the minimum concentration of gametocytes necessary for mosquito infection?

    <p>12 per cumm of blood</p> Signup and view all the answers

    Which type of malaria is considered the most serious and potentially fatal?

    <p>Malignant tertian malaria</p> Signup and view all the answers

    What characteristic is distinct for Plasmodium malariae?

    <p>Flower-like appearances</p> Signup and view all the answers

    What type of dots are associated with Plasmodium ovale?

    <p>Jame's dots</p> Signup and view all the answers

    What is the average number of merozoites formed in Plasmodium malariae?

    <p>8</p> Signup and view all the answers

    Which statement about the shape of female gametocytes across Plasmodium species is correct?

    <p>They are larger than male gametocytes</p> Signup and view all the answers

    What is the dormant stage of Plasmodium species that can occur in P. vivax and P. ovale?

    <p>Hypnozoites</p> Signup and view all the answers

    What type of malaria pigment is associated with P. falciparum?

    <p>Few solid blocks of black pigment</p> Signup and view all the answers

    During the erythrocytic stage, what is the primary receptor for merozoites on red blood cells?

    <p>Glycophorin</p> Signup and view all the answers

    Which statement accurately describes the morphology of merozoites?

    <p>They are pear-shaped bodies about 1.5 μm in length.</p> Signup and view all the answers

    What is the result of the rupture of mature schizonts in the erythrocytic stage?

    <p>Release of pyrogens</p> Signup and view all the answers

    What appearance is typical for P. vivax during the trophozoite stage?

    <p>Signet ring appearance with Schuffner’s dots</p> Signup and view all the answers

    In which stage of development does the nucleus of the amoeboid form start to divide by mitosis?

    <p>Late trophozoite stage</p> Signup and view all the answers

    Which feature helps merozoites attach to erythrocytes?

    <p>Their apex</p> Signup and view all the answers

    What does the QUANTITATIVE BUFFY COAT (QBC) method use to enhance visibility under fluorescent microscopy?

    <p>A special type of capillary tube</p> Signup and view all the answers

    Which Rapid Diagnostic Test (RDT) is used to distinguish between P. falciparum and non-P. falciparum species?

    <p>DiaMed OptiMAL IT</p> Signup and view all the answers

    What is the primary benefit of using insecticide treated nets (ITN) for malaria prevention?

    <p>They provide a barrier to prevent mosquito bites</p> Signup and view all the answers

    Which of the following is a molecular method used for diagnosing malaria?

    <p>Polymerase chain reaction (PCR)</p> Signup and view all the answers

    What is zooprophylaxis in the context of malaria control?

    <p>Using animal populations to divert mosquitoes away from humans</p> Signup and view all the answers

    In addition to humans, which primate is commonly infected by Plasmodium knowlesi?

    <p>Long-tailed macaque</p> Signup and view all the answers

    Which method is an example of a biological control method for malaria?

    <p>Larviparous fishes like Oreochromis niloticus</p> Signup and view all the answers

    What is the primary role of histidine-rich protein II (HRP II) in malaria diagnosis?

    <p>It is a water-soluble antigen produced by the parasite</p> Signup and view all the answers

    What is the primary method for detecting P. knowlesi infection?

    <p>PCR assay and molecular characterization</p> Signup and view all the answers

    What is the diagnostic characteristic of Babesia spp. infection in humans?

    <p>Maltese cross or tetrads formation</p> Signup and view all the answers

    Which stage of the Babesia life cycle occurs in the tick vector?

    <p>Merogony</p> Signup and view all the answers

    What type of tick serves as the definitive host for Babesia spp.?

    <p>Ixodid ticks</p> Signup and view all the answers

    Which mode of transmission is NOT associated with Babesia spp. infection?

    <p>Airborne transmission</p> Signup and view all the answers

    What is the infective form of Babesia spp. transmitted to humans?

    <p>Sporozoites</p> Signup and view all the answers

    Which Babesia species is known for causing 'Texas cattle fever'?

    <p>Babesia bovis</p> Signup and view all the answers

    What is an important characteristic of the life cycle of Babesia spp. in humans?

    <p>Can form gametes in blood</p> Signup and view all the answers

    Study Notes

    Protozoan Parasites

    • Produce spores like oocysts
    • Live intercellularly during part of their life cycle
    • Need one organism to complete their life cycle
    • Classified under Phylum Apicomplexa because of their apical complex
    • Apical complex is important for attachment and penetration into host cells

    Phylum Apicomplexa

    • Plasmodium spp.
      • Plasmodium falciparum - responsible for 90% of malarial cases
      • Plasmodium vivax - responsible for 90% of the malarial cases
      • Plasmodium malariae
      • Plasmodium ovale
      • Plasmodium knowlesi - 5th human malarial parasite, not usually common in humans (usually in monkeys, reported case in the Philippines in 2006)

    Babesia spp.

    • Babesia microti
    • Babesia divergens
    • Babesia bovis

    Other Protozoan Parasites

    • Cryptosporidium hominis
    • Cyclospora cayetanesis
    • Isospora belli
    • Toxoplasma gondii
    • Phylum Microspora
      • Enterocytozon bineusi
      • Encephalitozoon spp.
      • Vittaforma cornea
      • Pleistophora spp.
      • Brachila vesicularum
      • Microsporidium spp.

    Malaria

    • Derived from the Italian word "mal'aria" meaning "bad air"
    • "mal" meaning bad
    • "aria" meaning air
    • Believed to be caused by foul emanation from marshy soil
    • Considered the most important parasitic disease affecting humans
    • Vector: Female Anopheles mosquito
      • Primary vector: Anopheles minimus var. flavirostris
      • Other vectors: Anopheles litoralis, Anopheles maculates, Anopheles mangyamus
    • Final Host: Female Anopheles mosquito
    • Intermediate Host: Humans
    • Infective Stages: Sporozoites (humans), Gametocytes (mosquitoes)
    • Sexual stage: Happens in the mosquitoes
      • Infective stage: Gametocytes
    • Asexual stage: Happens in humans
      • Infective stage: Sporozoites

    Sources of Exposure to Infection

    • Vector-borne (arthropod-borne)
    • Other modes of transmission:
      • Imported malaria
        • From other countries endemic with malaria
        • Can be transferred to others

    World Health Organization (WHO)

    • Identified malaria as one of three major infectious disease threats, alongside HIV/AIDS and tuberculosis
    • Increasing cases of malaria, especially during the rainy season

    Sexual Phase of the Malaria Parasite

    • Occurs in the female Anopheles mosquito.
    • Sporozoites are formed during the sporogony phase.
    • Maturation and fertilization happen inside the mosquito's body.
    • When a female mosquito bites a human and ingests blood, male and female gametocytes enter the mosquito's stomach.
    • Male gametocytes mature into microgametes, while female gametocytes mature into macrogametes.
    • Fertilization occurs, forming a zygote.
    • The zygote elongates and becomes active, forming an ookinete.
    • The ookinete penetrates the mosquito's stomach wall and develops into an oocyst.
    • The oocyst grows and eventually ruptures, releasing sporozoites throughout the mosquito's body.

    Erythrocytic Stage of the Malaria Parasite

    • Merozoites, released by pre-erythrocytic schizonts, invade red blood cells.
    • Merozoites attach to red blood cells using glycophorin, a major glycoprotein on the red blood cell surface.
    • Merozoites transform into ring forms or young trophozoites, characterized by a central vacuole and peripheral cytoplasm.
    • As the ring form develops, it becomes irregular in shape and displays amoeboid movement, transitioning into the amoeboid or late trophozoite form.
    • The amoeboid form undergoes nuclear division (mitosis) followed by cytoplasmic division, eventually maturing into schizonts or meronts.
    • Mature schizonts release merozoites, which invade new red blood cells, starting the cycle again.
    • The rupture of mature schizonts releases pyrogens, causing fever.
    • The parasite consumes hemoglobin from red blood cells, leaving behind a hematin-globin pigment known as malaria pigment or hemozoin.
    • Malaria pigment appearance varies depending on the Plasmodium species:
      • P. vivax: numerous fine golden-brown dust-like particles.
      • P. falciparum: few, 1-3 solid blocks of black pigment.
      • P. malariae: numerous coarse dark brown particles.
      • P. ovale: numerous blackish brown particles.

    Plasmodium Species Characteristics

    • P. vivax:
      • Signet ring appearance with Schüffner’s dots (fine red granules).
    • P. malariae:
      • Elongated band or stab, stretching across the entire red blood cell.
      • Dots known as Ziemann’s stippling.
    • P. falciparum:
      • Compact with cytoplasmic vacuolation.
      • Almost ring-shaped, but with dark red or wedge-shaped dots (Maurer’s dots).
    • P. ovale:
      • Malarial stipplings called Jame’s dots.
    • Accole forms:
      • Crescentic masses (moon-shaped) found in the peripheral part of red blood cells.
      • Characteristic of P. falciparum.

    Gametogony in the Malaria Parasite

    • Gametocyte development generally occurs within internal organs, with mature forms appearing in circulation.
    • Mature gametocytes are round except in P. falciparum, where they are crescent-shaped or sausage-shaped.
    • Female gametocytes (macrogametocytes) are larger than male gametocytes (microgametocytes).
    • Gametocytes do not cause clinical illness but are crucial for malaria transmission.
    • A gametocyte concentration of 12 or more per cubic millimeter of blood in the human host is necessary for mosquito infection.

    Malignant Tertian Malaria

    • The most severe and potentially fatal type of malaria is malignant tertian malaria caused by P. falciparum.

    Malaria Diagnosis and Treatment

    • Quantitative Buffy Coat (QBC): Uses a special capillary tube with acridine orange; positive results appear bright green and yellow under a fluorescent microscope.
    • Rapid Diagnostic Test (RDT): Detects Plasmodium-specific antigens in a finger-prick blood sample.
      • Histidine-rich protein II (HRP II): A water-soluble protein produced by trophozoites and young gametocytes.
      • Plasmodium Lactate Dehydrogenase (LDH): Produced by both sexual and asexual stages and can distinguish between P. falciparum and other Plasmodium species.
    • Serologic Tests: Include indirect hemagglutination assay (IHA), indirect fluorescent antibody test (IFAT), and enzyme-linked immunosorbent assay (ELISA) to detect antibodies against malaria parasites.
    • Molecular Methods: Using polymerase chain reaction (PCR), suitable for low-case numbers or mixed infections.

    Plasmodium knowlesi

    • A primate malarial parasite common in Southeast Asia.
    • Causes malaria in long-tailed macaques (Macaca fascicularis).
    • Can infect humans.
    • Appearance is similar to P. malariae.
    • PCR assay and molecular characterization are the most reliable methods for detection and diagnosis.
    • P. vivax may interfere with PCR testing due to cross-reactivity.

    Babesia spp.

    • First described as the cause of "Texas cattle fever" or "red water fever."
    • Blood parasites that cause malaria-like infections.
    • "Babesiosis" refers to the pathology caused by Babesia spp.
    • Life cycle includes three stages:
      • Merogony in the red blood cells of tick vectors.
      • Gut and epithelial stage in ticks.
      • Sporogony in humans.
    • Vectors: Ticks, specifically Ixodes scapularis (hard ticks).
    • Ixodes scapularis can also carry Borrelia burgdorferi, the causative agent of Lyme disease.
    • Definitive Host: Ixodid ticks.
    • Intermediate Host: Humans or other mammals.
    • Infective form: Sporozoites.
    • Mode of Transmission: Bite of the nymphal stage of Ixodid ticks.
    • Other transmission modes: Blood transfusion, organ transplantation.
    • Diagnostic characteristic: Maltese cross or tetrads formation within red blood cells due to parasite division.
    • In humans, merozoites infect red blood cells continuously.
    • In mice, merozoites develop into gametes that, once ingested by a tick, travel through the tick and infect new red blood cells.

    Malaria Prevention

    • Mosquito repellent use.
    • Use of insecticide-treated nets (ITNs).
    • Prophylactic medication.
    • Wearing light-colored clothing that covers most of the body.

    Malaria Control

    • Environmental Cleanliness:
      • Stream cleaning to speed up water flow and expose areas to sunlight.
    • Indoor Residual Spraying.
    • Zooprophylaxis: Using water buffalo to divert mosquitoes away from humans.
    • Biologic Control Methods:
      • Bacillus thuringiensis: Larvicidal.
      • Larviparous fishes: e.g., Oreochromis niloticus.

    Intervals

    • Quantitative: Refers to the amount of parasites in the individual, this can be used for a drug regimen.
    • Prevent Transmission: Refers to medication that limits the ability of the parasite to spread from person to person.

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    Description

    Explore the fascinating world of protozoan parasites, particularly those classified under Phylum Apicomplexa. This quiz covers various species including Plasmodium and Babesia, examining their life cycles, modes of infection, and significance in human health. Test your knowledge on the characteristics and impacts of these organisms.

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