THE OSTIA VENAE HEPATICAE AND THE RETHROHEPATIC ...

ULTRASTRUCTURE OF PATHOGENIC NAEGLERIA SP. ISOLATED FROM
THREE CASES OF PRIMARY AMOEBIC MENINGOENCEPHALITIS
INFECTION FROM THAI PATIENTS
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Mangkalanond K, Tiewchaloren S, Junnu V, Pattavum A.
Department of Pathology, Faculty of Medicine Siriraj Hospital, 1 Department of Parasitology,
Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Department of Nursing, Faculty of
Medicine Siriraj Hospital, Mahidol University.
Key words : ultrastructure pathogenic Naegleria sp. strain
The proliferative form of Naegleria sp. isolated from three fetal Thai patients were
studied. The showed no differentiation from the pathogenic Naegleria fowleria reference strain. In
light microscope, the amoebae were active, progressive and had directional movement. They were
variable in sized and shape, the round amoebae were measuring about 8 to 30 mm. in diameter. The blunt
psuedopadia were protruded on the surface of the cell. In iron hematexyline stain, the cytoplasm appears
finely granular nucleolus giving it the appearance of a halo. Contractile and food vacuoles were demonstrated.
The ultrastructure of the pathogenic Neagleria sp. were not distinguished from that of the
control. Scanning electron microscope showed irregular outer surface was and points of contact between
them were conspicuous. Sucker-like structure on amoebostomes were found in either group.
Transmission electron microscope demonstrated that the surrounding unit membrane was composed of
two electron-dense layers. Rough endoplasmic reticulum appear as elongated tubular vesicle covered
with ribosomes. Dumb-bell-shape mitochondria was bound by two membranes separated by a clear
space. Both, cup-shaped and oval-mitochondria were also found. The vacuoles were bound by unit
membrane and contained electron-dense materials surrounded by whorl-like formations. The nuclear
membrane was bounded by two clearly visible electron dense layers that were seperated by a clear
space. A few pores could be seen within the nuclear envelope. Nucleolus at the central portion of the
nucleus appears dens. In conclusion, the results showed remarkable similarities between the pathogenic
Naegleria sp. and the control. Therefore, these pathogenic Naeglerias isolated from fatal cases of
amoebic meningoencephalites were considered as Naegleria fowleri.
(Mahidol J 1999; 6: 85-88.)
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