Malaria and Plasmodium spp. Stages

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Questions and Answers

What is a distinguishing characteristic of the Schizont stage of Plasmodium vivax?

Scattered pigment dots (correct)

Presence of a thin rim of cytoplasm

Single chromatin mass

Presence of distinct vacuoles

Which feature indicates a Ring stage of Plasmodium falciparum?

Occupation of the entire RBC volume

Enlarged red blood cells

Rounded with compact cytoplasm

Single or double chromatin mass with a vacuole (correct)

What is a characteristic of the Gametocyte stage of Plasmodium vivax?

Occupies only 1/6 of RBC volume

Presence of numerous irregular masses

Features a thin rim of cytoplasm

Rounded shape with a single chromatin mass (correct)

How does the infected RBC size differ between Plasmodium vivax and Plasmodium falciparum?

P.vivax: infected RBC enlarged; P.falciparum: RBC same size as others Signup and view all the answers

What is a common characteristic of multiple infections in RBCs caused by Plasmodium falciparum?

Common presence of multiple ring forms Signup and view all the answers

What stage is characterized by the presence of Schüffner’s dots and vacuoles in Plasmodium vivax?

Trophozoite Signup and view all the answers

Which stage of Plasmodium falciparum is identified by the presence of a chromatin dot?

Ring stage Signup and view all the answers

What is the definitive host for Babesia species?

Hard tick Signup and view all the answers

Which statement correctly describes Babesia microti infection in humans?

Infects humans primarily through insect bites Signup and view all the answers

How can one acquire the infective stage of Babesia spp.?

Blood transfusion from infected individuals Signup and view all the answers

What characteristic distinguishes Plasmodium vivax Ring stage?

Presence of chromatin dots and thin cytoplasm Signup and view all the answers

What characteristic distinguishes Plasmodium vivax from P. falciparum in blood films?

Presence of Schüffner's dots Signup and view all the answers

In which habitat do Babesia parasites predominantly reside during their life cycle?

In red blood cells Signup and view all the answers

Which of the following is a common mode of transmission for Babesia spp. aside from vector bites?

Blood transfusion Signup and view all the answers

During what stage are sporozoites introduced into humans?

During the bite of an infected hard tick Signup and view all the answers

What is the primary habitat for Babesia spp. during its life cycle in the vector?

Intestine of the tick Signup and view all the answers

Which morphological characteristic is used to identify polymorphic trypanosomes?

Presence of kinetoplast and flagella Signup and view all the answers

What distinguishes Trypanosoma cruzi from Trypanosoma brucei in terms of morphology and infection site?

Intracellular multiplication in host tissues Signup and view all the answers

Which vector is primarily associated with the transmission of Babesia spp.?

Ixodes tick Signup and view all the answers

How does Plasmodium spp. primarily survive and reproduce within the human host?

Replicating inside red blood cells Signup and view all the answers

What is the primary difference in the habitat of Leishmania donovani compared to Plasmodium spp.?

Leishmania donovani resides in macrophages Signup and view all the answers

What is the primary morphological characteristic of the amastigote form of Leishmania?

Oval or spherical shape Signup and view all the answers

Which statement accurately describes the distribution of sand flies?

Widely distributed in tropical and subtropical regions Signup and view all the answers

What is a key characteristic of the promastigote form of Leishmania?

Kinetoplast is located anterior to the central nucleus Signup and view all the answers

How do male sand flies primarily obtain nourishment?

By feeding on nectar and plant juices Signup and view all the answers

Which life stage is NOT part of the complete metamorphosis of sand flies?

Nymph Signup and view all the answers

What environmental conditions do most species of sand flies prefer for activity?

Dawn, dusk, and night Signup and view all the answers

Which morphological form of Leishmania is characterized by a long undulating membrane and a free flagellum?

Trypomastigote Signup and view all the answers

What is the typical size range for sand flies?

2-3 mm Signup and view all the answers

What is a distinguishing feature of microfilaria from Brugia malayi compared to Wuchereria bancrofti?

Its posterior end is pointed with two nuclei. Signup and view all the answers

Which structure in male mosquitoes is characterized by dense hairs?

Antennae. Signup and view all the answers

How do Culex larvae suspend themselves in water?

Diagonally with the siphon up. Signup and view all the answers

What is a notable characteristic of Anopheles larvae compared to Culex larvae?

No siphon present. Signup and view all the answers

Which statement accurately describes the egg-laying habits of Anopheles mosquitoes?

Their eggs are dark brown and laid singly. Signup and view all the answers

What is the structure of the mouthparts in male mosquitoes?

Plumose antennae and long maxillary palps. Signup and view all the answers

What distinguishes the larvae of Aedes from those of Anopheles?

Aedes larvae have a distinct siphon. Signup and view all the answers

Which of the following insects are known for their dark brown eggs with air cells?

Anopheles. Signup and view all the answers

What type of antennae do female mosquitoes possess?

Short and sporadic hair antennae. Signup and view all the answers

What do adult male mosquitoes NOT possess in terms of structure?

Thick maxillary palps with clubbing ends. Signup and view all the answers

Study Notes

Plasmodium spp.

Malaria is caused by Plasmodium spp.
Diagnostic stages for P. vivax
- Trophozoite Stage: Enlarged RBC, Schüffner's dots, Thin loop of cytoplasm, Single or double chromatin mass
- Schizont Stage: Almost fills the RBC, Numerous irregular chromatin masses and scattered pigment dots
- Gametocyte Stage: Rounded with compact cytoplasm and one chromatin mass, fills RBC, Schüffner's dots
Diagnostic stages for P. falciparum
- Ring Stage: Thin rim of cytoplasm, single chromatin dot, found inside a normal sized RBC (no enlarged RBC)
- Gametocyte Stage: Crescent or banana shaped, RBC is stretched
Key morphological differences between P. vivax & P. falciparum
- P. vivax: Thin rim of cytoplasm, single or double chromatin dots, enlarged infected RBCs, single infection per RBC
- P. falciparum: Very thin rim of cytoplasm, usually two chromatin dots, infected RBC same size as others, multiple infection per RBC

Babesia spp.

Distribution: Found in various parts of the world, including USA and Europe.
Habitat: Blood inside red blood cells
Transmission:
- Bite of infected hard tick (transmits infection from animals to humans)
- Blood transfusion
- Congenital (rare)
DH and Vector: Hard tick
IH: Human
RH: Rodents and cattle
Morphology:
- Sporozoites (pear-shaped) - found in salivary glands of ticks
- Intraerythrocytic stages: Ring forms with very thin cytoplasm and large chromatin (merozoites)
- Merozoites are 2-5 µm in size, pyriform, spherical, or ovoid, may be single, in pairs, or tetrads (Maltese cross)
Infective stage: Sporozoites (from tick bite), merozoites (from blood transfusion)

Leishmania spp.

Distribution: Worldwide, especially in tropical and subtropical countries.
Vector: Sand fly of the genus Phlebotomus (Old World) and Lutzomyia (New World)
Morphological forms:
- Amastigote: Oval or spherical, 2-5 x 1-2 µ, no free flagellum
- Promastigote: Elongated, 10-20 x 1-3 µ, central nucleus, anterior kinetoplast, anterior free flagellum
- Epimastigote: Elongated, 10-20 x 1-3 µ, kinetoplast anterior to the central nucleus, flagellum forms short undulating membrane before becoming free
- Trypomastigote: Spindle-shaped, 15-35 x 1-3 µ, kinetoplast posterior, long undulating membrane, free flagellum

Brugia malayi

Distribution: Worldwide (tropical and subtropical regions)
Transmission: Mosquitoes
Morphology: The microfilaria is similar to Wuchereria bancrofti but smaller. The posterior end is pointed with 2 nuclei, the distal is large and extends to the tail, the proximal one is smaller.
Life cycle: Similar to Wuchereria bancrofti

Mosquitoes

General morphology: Body composed of head, thorax, and abdomen
- Head: Compound eyes, 15 segmented antennae (plumose in males, pilose in females), 4 segmented maxillary palps
- Thorax: 3 segments (prothorax, mesothorax, metathorax), each with a pair of legs, mesothorax carries wings
- Abdomen: 10 segments, last 2 modified into male (claspers) and female (cerci)
Culex
- Non-spotted wings
- Maxillary palps: Short and thick
- Antennae: Short & sporadic hair in females, Long & dense hair in males
- Eggs: Laid in batches, dark brown
- Larvae: Suspended diagonally from surface of water, long and thick siphon
- Pupae: Non-feeding, respiratory trumpets are tubular
Anopheles
- Spotted wings
- Maxillary palps: Long
- Antennae: Short & sporadic hair in females, Long & dense hair in males
- Eggs: Laid singly, dark brown with air cells
- Larvae: Parallel to surface of water, no siphon
- Pupae: Non-feeding, respiratory trumpets are funnel-shaped

Toxoplasma gondii

Distribution: Worldwide
DH: Cats and other felines
IH: Humans
Transmission: Feline feces, undercooked meat, contaminated water, mother to baby
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Test your knowledge on the diagnostic stages of Plasmodium spp. that cause malaria, particularly P. vivax and P. falciparum. The quiz covers key morphological differences and various life stages of these parasites. Understanding these concepts is crucial for proper diagnosis and treatment of malaria.