in the genus angiostrongylus , a total of 21 species have been described , including 2 species which cause diseases in humans such as angiostrongylus cantonensis and angiostrongylus costaricensis . a. cantonensis causes eosinophilic meningoencephalitis in humans damaging the brain tissues , which result in bleeding , inflammation , and granuloma formation . a. cantonensis was first found from the lungs of rats rattus norvegicus and rattus rattus in 1935 by chen in china . the first human case infected with a. cantonensis was reported by nomura and lin in 1945 in taiwan . in 1962 , rosen et al .   reported 2 cases of eosinophilic meningoencephalitis caused by a. cantonensis and called the worm as the rat lungworm . after then , a. cantonensis has been detected in madagascar , hawaii , south east asia , and japan . meanwhile , a. costaricensis was detected for the first time in costa rica , and then in middle america and north america . in vietnam , eosinophilic meningoencephalitis caused by a. cantonensis was first detected in 1976 . phan   reported 2 human cases ( 3- and 7-year old ) with symptoms like fever , vomiting , snatched legs , leg pain , paralyses , positive meningoencephalitis , and eosinophillia ( 29 - 59% ) . in addition , an   reported 15 children cases ( 1 - 15 years old ) of eosinophilic meningoencephalitis due to a. cantonensis infection in the national children hospital during 1995 - 2000 . after then , de et al .   reported 5 cases of angiostrongyliasis in 2004 and another case in 2008 . we report here an additional case of human angiostrongyliasis caused by a. cantonensis ; the species was molecularly confirmed for the first time in vietnam . the patient was a 23-year - old female residing in the chi thao village , quang yen district , cao bang province , north vietnam . in july 2013 , she felt dim eyes and a bulge - sticking pain in her left eye for some days at home . she visited the provincial hospital and then the hospital of hanoi medical university , hanoi , vietnam . in the hospital , a clinical examination and an eye endoscopy were carried out , and a nematode worm was seen in the left eye . the body of this worm was thin and long and measured 22 mm in length and 0.3 mm in width ( fig . it was morphologically suggested as an immature ( female ) worm of a. cantonensis . by the molecular method using a portion of 18s rrna gene , this vietnamese angiostrongylus was sequenced and compared with different worldwide a. cantonensis isolates from genbank ( table 1 ) . a comparison was made on 522 nucleotides of a portion of 18s rrna gene between the vietnamese angiostrongylus and isolates from usa ( ac - no ) , brazil ( ac - br ) , china ( ac - sz1 , ac - sz2 , ac - qy , and ac - wz ) , costa rica ( ac - cr ) , and uk ( av - uk ) . the results revealed 99% identity with other a. cantonensis reported in genbank ( fig . the symptoms in angiostrongyliasis patients in vietnam included headache ( 15/15 ) , fever ( 12/15 ) , vomiting ( 11/15 ) , harden neck ( 8/15 ) , and eosinophillia ( 31.5 - 48.5% ) . in 2004 , de et al .   also reported 5 cases ( 19-month to 10-year - old ) of angiostrongyliasis with the symptoms of headache ( 5/5 ) , fever ( 5/5 ) , vomiting ( 4/5 ) , snatched leg ( 5/5 ) , disordered reflected knee ( 5/5 ) , leg paralysis ( 5/5 ) , positive meningoencephalitis ( 5/5 ) , eosinophillia ( 5/5 with 19 - 30% ) , and positive elisa with angiostrongylus antigen ( 5/5 ) . these symptoms were similar to those reported previously in taiwan . however , eosinophilic meningoencephalitis due to a. cantonensis occurred more and more often in vietnam . the parasitic place of angiostrongylus was usually the brain , but can be in other places , including the eyes . in 2001 , xuan et al .   also reported a case infected with a. cantonensis in the eye . the incidence of ocular angiostrongyliasis is low ; however , it can cause hypopsia or even vision loss , which would seriously affect the quality of the life of patients . reviewed total 42 ocular cases reported worldwide ; nearly a half of them were from thailand and the rest were from other asian countries , including sri lanka , india , taiwan , vietnam , malaysia , japan , and indonesia . in most cases , worms were found from the anterior chamber or vitreous fluid , and in a few cases they were from the retina or subretina . the majority of the ocular cases was not associated with cerebrospinal symptoms ; only 12 of the 42 cases suffered from eosinophilic meningitis . in our case , the patient felt dim eyes and a bulge - sticking pain in her left eye ; however , she developed no further symptoms like meningoencephalitis . the phylogenetic tree of a. cantonensis vietnam and other strains from different countries targeting a part of 18s rrna nucleotide sequences was constructed by the neighbor - joining ( nj ) method using mega4.0 . it has been shown that the vietnamese a. cantonensis is located in the same group with other a. cantonensis isolates available in genbank ( fig . the present study is the first to identify the species of the nematode by a molecular method in vietnam .
a 23-year - old female residing in a village of cao bang province , north vietnam , visited the hospital of hanoi medical university in july 2013 . 
 she felt dim eyes and a bulge - sticking pain in her left eye for some days before visiting the hospital . in the hospital , a clinical examination , an eye endoscopy , and an operation were carried out . 
 a nematode specimen was collected from the eye of this patient . 
 the body of this worm was thin and long and measured 22.00.3 mm . 
 it was morphologically suggested as an immature female worm of angiostrongylus cantonensis . by a molecular method using 18s rrna gene , 
 this nematode was confirmed as a. cantonensis . 
 this is the first molecular study for identification of a. cantonensis in vietnam .