25 Questions
In which regions is the transmission of malaria more intense?
Warmer regions closer to the equator
What is the primary mode of transmission of malaria?
The bite of infected female Anopheles mosquitoes
In which areas is transmission of malaria less likely to occur?
At very high altitudes, during colder seasons, in deserts, and in areas with successful control/elimination programs
What are the most common species of Plasmodium that cause malaria?
P.vivax and P.falciparum
What is the pathogen responsible for causing malaria?
Plasmodium spp.
What is the mode of transmission of malaria through contaminated needles?
sharing of contaminated needles among IV drug abusers
What is the term for the transmission of malaria from an infected mother to her child during pregnancy or childbirth?
congenital transmission
What is the stage of the Plasmodium life cycle that is infectious to humans?
sporozoite
What is the intermediate host in the life cycle of Plasmodium?
human
How often does the schizogonic cycle occur in red blood cells for P. vivax?
every 48 hours
What are the characteristic features of the ring-stage trophozoites in Plasmodium falciparum?
Small ring; sometimes 2 dots & multiple rings
What is the characteristic feature of the schizonts in Plasmodium malariae?
Less than 12 merozoites
What is the shape of the gametocytes in Plasmodium falciparum?
Banana shaped
What is the effect of the liberation of merozoites and malarial pigment on the red blood cells?
Rupture of infected RBCs and destruction of normal RBCs
What is the characteristic feature of the red blood cells infected with Plasmodium vivax?
Enlarged; stippling
What is the shape of the male gametocyte of Plasmodium falciparum, and what is the characteristic of its cytoplasm?
Banana-shaped, light blue cytoplasm.
How does the size of the female gametocyte of Plasmodium vivax compare to that of Plasmodium falciparum?
The female gametocyte of Plasmodium vivax is larger than that of Plasmodium falciparum.
What is the characteristic of the nucleus of the male gametocyte of Plasmodium malariae?
Large, diffuse nucleus.
How does the cytoplasm of the female gametocyte of Plasmodium ovale compare to that of Plasmodium falciparum?
Both have dark blue cytoplasm.
What stage of development is depicted in slide 23 for Plasmodium malariae?
Developing gametocyte.
What is the role of tachysporozoite in the life cycle of malaria?
Tachysporozoite grows in the hepatic cell, multiplies to form exoerythrocytic schizonts, and then invades RBCs to produce malaria.
What is the term for the process of formation of merozoites from trophozoites in the erythrocytic stage?
Schizogony
What is the role of bradysporozoite in the life cycle of malaria?
Bradysporozoite causes the relapse of malaria by staying in the hepatic cells and multiplying later.
What is the characteristic of infected red blood cells in Plasmodium ovale?
Enlarged and most of them are oval in shape.
What is the stage of the malaria life cycle where diagnosis is typically made?
Erythrocytic stage
Study Notes
MORPHOLOGY
- Plasmodium spp. have different morphologies:
- Schizonts:
- Plasmodium falciparum: rare, > 12 merozoites
- Plasmodium vivax: > 12 merozoites
- Plasmodium malariae: < 12 merozoites
- Plasmodium ovale: < 12 merozoites
- Gametocytes:
- Plasmodium falciparum: banana-shaped, male (shorter and fatter), female (longer and thinner)
- Plasmodium vivax: round, male and female
- Plasmodium malariae: round, male and female
- Plasmodium ovale: round, male and female
- Schizonts:
COMPARISON
- Plasmodium spp. have different characteristics:
- RBC: normal (P. falciparum), enlarged (P. vivax), normal (P. malariae), enlarged (P. ovale)
- Presence in blood: ring and gametocyte (P. falciparum), all stages (P. vivax), all stages (P. malariae), all stages (P. ovale)
- Trophozoite shape: small ring (P. falciparum), ring and amoeboid (P. vivax), ring and band form (P. malariae), ring and irregular shape (P. ovale)
- Schizonts: rarely seen (P. falciparum), > 12 merozoites (P. vivax), < 12 merozoites (P. malariae), < 12 merozoites (P. ovale)
PATHOGENESIS
- Malaria pathogenesis:
- Paroxysm (attack of malaria): liberation of merozoites and malarial pigment, rupture of infected RBCs and destruction of normal RBCs, stimulating phagocytes to grow and enhance function
DISTRIBUTION
- Malaria distribution:
- Wide distribution in many tropical and subtropical regions
- Transmission does not occur at high altitudes, during colder seasons, or in deserts
- Transmission is more intense in warmer regions closer to the equator, especially in Africa and Papua New Guinea
ROUTE OF TRANSMISSION
- Malaria transmission:
- Naturally acquired infections via infected female Anopheles mosquitoes
- Blood transfusion, sharing of contaminated needles, and congenital transmission
LIFE CYCLE
- Plasmodium spp. life cycle:
- Intermediate host: human
- Definitive host: female Anopheles mosquito
- Infective stage: sporozoite
- Infective mode: mosquito bite
- Parasitic position: liver and red blood cells
- Transmitted stage: gametocytes
- Schizogonic cycle in red cells: 48 hours (P. vivax), 36-48 hours (P. falciparum)
- Sporozoite: tachysporozite and bradysporozite
- Life cycle in mosquito: gametocytes, gametes, zygote, oocyst, sporozoite
- Life cycle in human body: exoerythrocytic stage, erythrocytic stage, gametogenesis
LAB DIAGNOSIS
- Not mentioned in the provided text
TREATMENT AND PREVENTION
- Not mentioned in the provided text
Identify and describe the morphology of different Plasmodium species, including falciparum, vivax, malariae, and ovale. Learn about the characteristics of schizonts and gametocytes.
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