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Journal of Clinical Microbiology, August 2004, p. 3891-3893, Vol. 42, No. 8
0095-1137/04/$08.00+0 DOI: 10.1128/JCM.42.8.3891-3893.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.
Solitary Neurocysticercosis Case Caused by Asian Genotype of Taenia solium Confirmed by Mitochondrial DNA Analysis
Hiroshi Yamasaki,1* Shigeo Matsunaga,2,
Koji Yamamura,2 Chia-Cheng Chang,2 Shunji Kawamura,3,
Yasuhito Sako,1 Minoru Nakao,1 Kazuhiro Nakaya,4 and Akira Ito1
Department of Parasitology,1
Animal Laboratory for Medical Research, Asahikawa Medical College, Asahikawa,4
Department of Neurosurgery, Yokohama Minami Kyosai Hospital,2
and Department of Pathology, Yokohama Rosai Hospital, Yokohama, Japan3
Received 25 December 2003/
Returned for modification 31 March 2004/
Accepted 20 April 2004

ABSTRACT
A Japanese woman presenting with neurologic symptoms was presumptively
diagnosed with neurocysticercosis based on imaging findings.
Hooklets in the scolex of the resected lesion were not confirmed
through histopathological observation. However, the illness
was confirmed by mitochondrial DNA analysis to be a solitary
neurocysticercosis case caused by the Asian genotype of
Taenia solium.

CASE REPORT
A 53-year-old Japanese woman developed aphasia and numbness
of the right arm beginning 29 November 2002. The patient was
admitted to the Department of Neurosurgery, Yokohama Minami
Kyosai Hospital, Yokohama, Japan, on 16 December 2002 with complaints
of aphasia and numbness of the right arm. On admission, cerebral
computed tomography (CT) showed a low-density area in the left
frontal lobe (Fig.
1A), and the lesion appeared as a ringlike
small mass (hole-with-dot imaging) with a diameter of 2 cm surrounded
with edema at the same site in the CT scan with contrast enhancement
(Fig.
1B). Magnetic resonance imaging (MRI) showed the lesion
with a low-intensity signal in a T1-weighted image (Fig.
1C)
and a high-intensity signal in a T2-weighted image (Fig.
1D).
Perifocal edema is evident in the T2-weighted image. The lesion
was enhanced after administration of gadolinium-diethylenetriaminepentaacetic
acid (Fig.
1E and F). Neurocysticercosis (NCC) caused by a
Taenia solium cysticercus was strongly suspected based on the imaging
findings, and total removal of the mass was performed for differentiation
from a tumor (Fig.
2A). The mass was located near the surface
of the brain and had prominent surrounding gliosis. Histopathological
examination of the resected lesion revealed suckers and a spiral
canal unique to the taeniid cysticercus, but no hooklet was
observed in any section (Fig.
2B). Postoperative examinations
for screening of other visceral organs including X rays of the
extremities and the whole body showed no other abnormality.
After surgery, the patient recovered well with no residual deficit,
resuming her preillness activity. She repeated extensive travels
to France, Spain, Portugal, India, and Southeast Asian countries
(Thailand, Myanmar, Vietnam, and Malaysia) that she had taken
during the period from 1993 to 2001.
Serological examination and mitochondrial DNA analysis.
A blood sample was obtained from the patient with informed consent
according to guidelines from institutional review boards at
Yokohama Minami Kyosai Hospital. Serological confirmation of
immunoblots using both purified glycoproteins (
5) and a recombinant
chimeric antigen (
9) was carried out at Asahikawa Medical College
before surgical operation; however, there was no detectable
specific antibody response against either antigen (data not
shown). For definitive diagnosis of the causative agent, mitochondrial
DNA analysis was performed using a small piece of a formalin-fixed,
paraffin-embedded specimen. The paraffin was melted in a heat
block at 70°C, and a tiny amount of parasite material was
separated. The parasite was lysed in 60 µl of 0.02 N sodium
hydroxide containing proteinase K at 90°C for 15 min. After
removal of the proteinase K by use of phenol-chloroform, the
resulting solution was used directly as template DNA for the
amplification of the cytochrome
c oxidase subunit 1 gene (
cox1).
Two products, one of approximately 1.6 kb and one of 984 bp,
were successfully amplified by using 5'-TTGTTATAAATTTTTGATTACTAAC-3'
(
16) as the forward primer and 5'-TCCACTAAGCATAATGCAAAAGGC-3'
(
7) and 5'-GACATAACATAATGAAAATG-3', respectively, as the reverse
primers (reference
16 and data not shown). The PCR protocol
consisted of 35 cycles of 94°C for 1 min, 60°C for 1
min, and 72°C for 2 min plus 1 cycle of 72°C for 5 min
using the Ex
Taq DNA polymerase Hot Start version (Takara Bio
Inc., Shiga, Japan). The samples for DNA sequencing were prepared
using the ABI PRISM BigDye Terminator Cycle Sequencing Ready
Reaction kit, and DNA sequencing was performed on an ABI PRISM
310 Genetic Analyzer.
In Fig. 3, the partial nucleotide sequence of the taeniid specimen is aligned with nucleotide sequences of cox1 from human taeniid cestodes. Although some differential nucleotides are dispersed over the cox1 sequences, the representative three nucleotides at positions 672, 690, and 723 are shown as diagnostic markers for taeniid species or T. solium genotypes. A nucleotide at position 672 is for differentiation of taeniid species, and the other two, at positions 690 and 723, are pertinent for differentiation of two genotypes of T. solium (7, 15). In this case, the nucleotides at positions 690 and 723 are guanine and cytosine, respectively, indicating that the resected cysticercus has the Asian genotype of T. solium. Consideration of the patient's travel history revealed possibilities of exposure to T. solium eggs during her stays in India or other Southeast Asian countries where T. solium NCC is still endemic.
NCC is one of the most serious parasitic diseases of public
health importance and is currently recognized as a reemerging
disease in both developed and developing countries (
1,
10,
11,
12). Imaging diagnosis of NCC using CT and MRI is routinely
performed, and approximately 10% of NCC cases are easily diagnosed
based upon imaging findings (
2). Serological examination is
also reliable and sensitive for NCC patients with multiple cysts
but not for those with a solitary cyst (
3,
8,
13,
14). As in
this case, it is not always possible to observe the characteristic
hooklets of
T. solium through histopathological examination
due to either technical problems or incomplete formation of
hooklets (
6). Moreover, there might be anticipated cysticercosis
caused by taeniid species of zoonotic origins other than
T. solium. We are also interested in molecular evaluation of the
racemose form of cysticerci,
Cysticercus racemosus. Thus, mitochondrial
DNA analysis is useful for routine identification of taeniid
cestodes and particularly for correlation between pathogenicity
and genotypes of
T. solium (
4) when parasite materials are available.

ACKNOWLEDGMENTS
This work was supported in part by a grant-in-aid for scientific
research from the Japan Society for Promotion of Science (grant
no. 14256001) to A.I.

FOOTNOTES
* Corresponding author. Mailing address: Department of Parasitology, Asahikawa Medical College, Midorigaoka Higashi 2-1-1-1, Asahikawa 078-8510, Japan. Phone: 81 166 68 2421. Fax: 81 166 68 2429. E-mail:
hyamasak{at}asahikawa-med.ac.jp.

Present address: Department of Neurosurgery, National Hospital, Yokohama Medical Center, Yokohama 245-8575, Japan. 
Present address: Department of Pathology, Tokyo Women's Medical University, Tokyo 162-8666, Japan. 

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Journal of Clinical Microbiology, August 2004, p. 3891-3893, Vol. 42, No. 8
0095-1137/04/$08.00+0 DOI: 10.1128/JCM.42.8.3891-3893.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.