human sparganosis is a zoonosis caused by plerocercoid larvae ( = spargana ) of pseudophyllidean ( now classified as diphyllobothriidean ) tapeworms . in asia , s. erinaceieuropaei is responsible for this disease , whereas spirometra mansonoides is important in the americas .
this parasite can be found anywhere in the body including the central nervous system . in rare cases ,
a sparganum involves the spinal cord , usually at the thoracic to lumbar levels [ 7 - 15 ] . to our knowledge ,
here , we describe a case of cauda equina syndrome with molecular evidence for identification of the causative agent and review the literature of sparganosis involving the spinal cord .
the patient was a 52-year - old female sugarcane farmer who lived in a rural community of suphan buri province , central thailand .
she presented to our hospital complaining of lumbodorsal pain for the previous month , progressive symmetrical paraparesis with sensory impairment and radiculopathy for 2 weeks , and bowel / bladder dysfunction for 3 days .
she had no history of ingesting inadequately cooked frogs , snakes , or birds . on examination ,
motor strength of the left lower extremity decreased from grade v ( normal ) to grade iii in the hamstrings , iliopsoas , and quadriceps muscles ; grade i - ii in the ankle and toe plantar flexor muscles ; and grade 0 in the ankle dorsiflexors muscles and the extensor hallucis longus muscle . for the right lower extremity ,
sensations were decreased below the l2 dermatome on both sides with peri - anal anesthesia , and the knee and ankle jerk were absent on both sides .
routine biochemical and hematological investigations were within normal limits except for an increase of absolute eosinophil count in the peripheral blood ( 0.4610/l ) .
mri of the whole spine showed multiple intradural extramedullary serpiginous - mass lesions in the subarachnoid space continuously from the prepontine to the anterior part of the medulla oblongata levels , c7 , t2-t8 , and t12 vertebral levels distally until the end of the thecal sac , and filling - in of the right s1 neural foramen ( fig .
attempts of spinal tapping to obtain a cerebrospinal fluid ( csf ) sample were unsuccessful .
laminectomy at l1 and l2 level was performed to obtain a tissue sample for histopathological examinations . during the operation
, we noticed a matted mass involving nerve roots with remarkable inflammation and multiple cystic lesions containing pus ; no csf was seen due to obstruction by the mass .
a small piece of tissue from the matted mass was removed and fixed in formalin and processed for paraffin embedding .
histological examinations demonstrated a degenerated solid section of a folded cestode larva having irregular folding tegument which was homogenously eosinophilic in color .
2b arrows ) , which is a characteristic feature of a cestode larva , were seen .
there were mild inflammatory cell infiltrations including eosinophils , lymphocytes , a few plasma cells , and neutrophils in the larval section ( fig .
after the histopathological confirmation , serological tests for detection of specific antibodies in the serum was performed .
using elisa , we detected a high titer of specific igg antibodies against s. erinaceieuropaei sparganum partially purified antigen .
the serum was negative for cysticercosis by elisa and also negative for gnathostomiasis , paragonimiasis , fascioliasis , and angiostrongyliasis by immunoblotting . for molecular identification of the causative parasite species
, dna was extracted from 10 m unstained serial sections ( cut from the formalin - fixed paraffin - embedded specimen ) attached to glass slides using a dexpat kit ( takara bio inc . ,
amplification of mitochondrial cytochrome c oxidase subunit 1 ( cox1 ) gene by pcr was performed in a 25 l reaction mixture .
a fragment of cox1 gene was amplified using the primers se658-f ( 5'-ttt gat cct ttg ggt ggt gg-3 ' ) and se1124-r ( 5'-acc aca aac cac gtg tca tg-3 ' ) , which were designed from the cox1 gene of s. erinaceieuropaei ( genbank accession no .
ab369250 ) . pcr was carried out using a geneamp pcr system 9700 ( applied biosystems , singapore ) .
the reaction was carried out in a 25 l volume containing 2.5 l of 10x faststart high fidelity reaction buffer with 18 mm mgcl2 ( roche , mannheim , germany ) , 200 m of each deoxyribonucleotide triphosphate , 0.2 m of each primer ( invitrogen , carlsbad , california , usa ) , and 0.625 units of faststart high fidelity enzyme blend ( roche ) .
the amplification procedure consisted of 35 cycles at 95 for 30 sec ( denaturation ) , 59 for 30 sec ( annealing ) , and 72 for 45 sec ( extension ) , with a final extension at 72 for 10 min .
amplified product was run on a 1% agarose gel ; a 467 bp fragment was cut and sequenced using the megabace 1000 dna analysis system ( ge healthcare , piscataway , new jersy , usa ) .
the cox1 gene sequence of s. erinaceieuropaei obtained from the patient was analyzed by blast - n search via ncbi .
the partial cox1 sequence of s. erinaceieuropaei from the patient , which was deposited in the genbank database ( no .
kc551943 ) , was almost completely ( 97 - 99% identity ) identical with those of s. erinaceieuropaei from various geographical localities . from these results ,
after laminectomy at l1 and l2 level , the patient received corticosteroid and praziquantel therapy , and her lumbosacral pain moderately improved .
however , she persistently complained of a dull , uncomfortable sensation on both buttocks . at follow - up after 1 month , paraparesis with sensory impairment , urination , and defecation difficulties still persisted .
this study protocol was approved by siriraj institutional review board certificate of approval ( coa no .
it is caused by the larvae of the tapeworm genus spirometra , whose definitive hosts are domestic and wild cats and dogs
. human infections usually occur in the following 3 ways ; drinking untreated water containing infected copepods ; ingesting raw or inadequately cooked flesh of snakes , frogs , or birds infected with spargana ; and applying the flesh of an infected frog as a poultice to a wound .
the disease usually involves the subcutaneous tissue or muscles of the chest , abdominal wall , or limbs .
central nervous system involvement is relatively rare , involvement of the spinal cord , in particular , is extremely rare . in the literature
[ 7 - 10,12 - 16 ] , including the present study , 10 cases of spinal sparganosis have been reported .
these were 6 males and 4 females whose ages ranged from 10 to 59 years ( mean age ; 38.9 years ) .
the sparganum more commonly involved intradural ( 70% ) than extradural   sites , usually at the thoracic level [ 7 - 10,12,13 ] , followed by the cervical level . including the present case ,
our patient demonstrated long and multiple intradural extramedullary lesions extending from the prepontine to the anterior part of medulla oblongata levels , c7 , t2-t8 , and t12 vertebral levels distally until s1 level .
clinical manifestations included sensory disturbances ( 70% ) , weakness of the limbs ( 60% ) , pain ( 60% ) , and voiding difficulty ( 50% ) .
the mean duration of symptoms before diagnosis was 9.4 months ( range ; 3 days to 3 years ) .
the prognosis was good or fair . in nearly all of the spinal sparganosis patients ,
our patient was unique in that the lesions were at multiple levels from the prepontine down to the end of the thecal sac .
the patient presented with severe lumbodorsal pain due to a mass compressing the adjacent spinal cord and resulting spinal cord edema .
pain in the nerve root may occur long before the signs of spinal cord compression have developed . in our patient , lumbodorsal pain developed before paraparesis and bowel / bladder involvement .
the route of the entry of worms into the spinal cord remains unclear , but hematogenous spread seems likely .
it is hard to diagnose sparganosis clinically and to differentiate it from neoplastic and inflammatory disorders or other parasitic visceral larva migrans because it is rare and has non - specific manifestations .
we could not find any specific features for diagnosis in neuroradiological imaging of these cases .
elisa for detecting anti - sparganum igg antibody is highly sensitive ( 85.7 - 100% ) and specific ( 95.7% ) .
however , the elisa technique can not identify the causative worm at the species level .
pcr - based molecular techniques should be used for identification of the causative pathogens of infectious diseases .
recent development of pcr / sequencing technique for dnas from formalin - fixed paraffin - embedded ( ffpe ) tissues kept for many years enabled us to perform the retrospective re - appraisal of individual cases and also epidemiological studies . in conclusion , we report here a rare case of sparganosis presented as cauda equina syndrome .
pcr - based identification of the causative agent using ffpe tissues led us to the accurate and definite diagnosis .
 a 52-year - old woman presented with lower back pain , progressive symmetrical paraparesis with sensory impairment , and sphincter disturbance . magnetic resonance imaging ( mri ) of the whole spine revealed multiple intradural extramedullary serpiginous - mass lesions in the subarachnoid space continuously from the prepontine to the anterior part of the medulla oblongata levels , c7 , t2-t8 , and t12 vertebral levels distally until the end of the theca sac and filling - in the right s1 neural foramen . 
 sparganosis was diagnosed by demonstration of the sparganum in histopathological sections of surgically resected tissues and also by the presence of serum igg antibodies by elisa . 
 dna was extracted from unstained tissue sections , and a partial fragment of mitochondrial cytochrome c oxidase subunit 1 ( cox1 ) gene was amplified using a primer set specific for spirometra spp . cox1 . 
 after sequencing of the pcr - amplicon and alignment of the nucleotide sequence data , the causative agent was identified as the larva of spirometra erinaceieuropaei . 
INTRODUCTION
CASE RECORD
DISCUSSION