Chilomastix mesnili

Introduction

Chilomastix mesnili is cosmopolitan in distribution although found more frequently in warm climates. It is thought to be non-pathogenic although the trophozoite has been associated with diarrheic stool. This is the largest flagellate found in man with an incidence of 1-10% being in the large intestine.

Chilomastix mesnili life cycle

Chilomastix mesnili life cycle


Morphology of the Trophozoite

The trophozoites of C. mesnili are pear shaped and measure 6-20μm in length. They have one large nucleus with a small karyosome and three flagella that extend from the nucleus at the anterior end of the parasite. A distinct oral groove or cytosome can be seen near the nucleus with its sides being supported by two filaments. They are known to move in a directional manner.

Chilomastix mesnili. Iodine stain

Chilomastix mesnili. Iodine stain

Chilomastix mesnili trophozoites

Chilomastix mesnili trophozoites

Chilomastix mesnili trophozoite (pointed end)

Chilomastix mesnili trophozoite (pointed end)

Morphology of cysts

The cysts are 6-9μm; they have a large single nucleus with a large karyosome. They also have a prominent side knob giving it a characteristic lemon shape. The cytosome is evident with a curved shepherds crook fibril. It also has a characteristically coiled filament which when stained is darker in color.

Chilomastix mesnili cysts Iodine stain

Chilomastix mesnili cysts Iodine stain

Chilomastix mesnili cyst (lugol)

Chilomastix mesnili cyst (lugol)

Chilomastix mesnili cyst

Chilomastix mesnili cyst

Chilomastix mesnili - cyst in an unstained concentrate

Chilomastix mesnili – cyst in an unstained concentrate

 

Chilomastix mesnili cysts shape

Chilomastix mesnili cysts shape


Laboratory Diagnosis

The characteristic lemon shaped cysts can be seen in a formol-ether concentrate. Motile organisms can be seen in a wet preparation of a fresh stool however the characteristic morphology is evident in a permanently stained preparation. Table 3-1 details useful morphological features that are similar between species of flagellate and are used in laboratory diagnosis.


References:
– CDC

– www.atlas-protozoa.com

Share This Post

Related Articles

Leave a Reply

You must be Logged in to post comment.

© 2020 Medical Laboratories. All rights reserved. Site Admin · Entries RSS · Comments RSS
Powered by WordPress · Powered by Medical Labs