Flashcards on Parasitic Protozoa in Ectothermic Vertebrates

Parasitic Protozoa in Ectothermic Vertebrates: A Student Guide

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What general shape and orientation do gamonts of most Hepatozoon species have within host erythrocytes?

They are not recurved, forming two limbs of similar length that extend for most of the host cell, usually blunt at both ends with one end slightly wid

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Gregarine & Hepatozoon-like Parasites — Hemogregarines general

145 cards

Card 1

Question: What general shape and orientation do gamonts of most Hepatozoon species have within host erythrocytes?

Answer: They are not recurved, forming two limbs of similar length that extend for most of the host cell, usually blunt at both ends with one end slightly wid

Card 2

Question: How can some Hepatozoon gamonts appear when the posterior end is strongly tapered?

Answer: They may show a recurved “tail” that can sometimes reach the gamont midbody.

Card 3

Question: What cytoplasmic features can be present in Hepatozoon gamonts?

Answer: Cytoplasm may be uniform or contain many rounded vacuoles; some species have scattered azurophilic granules.

Card 4

Question: Which morphometric characters are useful taxonomically for hemogregarine gamonts?

Answer: Length, maximum width, length×width (LW), and length/width ratio (L/W), used with sporogonic characters.

Card 5

Question: What are typical size ranges for mature Hepatozoon gamonts?

Answer: Apparently mature gamonts may be as short as ~10 μm and can exceed 20 μm, but most are 14–18 μm.

Card 6

Question: Where is the nucleus typically located in Hepatozoon gamonts and what shapes can it have?

Answer: Nucleus is slightly anterior to midbody (midbody or anterior second quarter), often squarish or triangular (“saddle-shaped”), sometimes elongate and n

Card 7

Question: How do young gamonts (trophozoites) differ morphologically from mature gamonts?

Answer: They are shorter and narrower, elongate with prominent irregular nuclei that may occupy most of the parasite body and a often vacuolated cytoplasm.

Card 8

Question: Are nuclei in mature gamonts always regular?

Answer: No — irregular nuclei are common; nuclei can be fragmented into small pieces or two halves in some cases.

Card 9

Question: Is merogony within erythrocytes common among hemogregarines?

Answer: Apparent meronts within erythrocytes are rare; known only for the crocodilian parasite Hepatozoon pettiti.

Card 10

Question: How do infected host erythrocytes typically appear when harboring hemogregarine gamonts?

Answer: Host cells are often distorted and enlarged with displaced or elongated nuclei; they are seldom lysed.