title: Amoebic liver abscess in northern Sri Lanka: first report of immunological and molecular confirmation of aetiology.
abstract: Since 1985, amoebic liver abscess (ALA) has been a public health problem in northern Sri Lanka. Clinicians arrive at a diagnosis based on clinical and ultrasonographic findings, which cannot differentiate pyogenic liver abscess (PLA) from ALA. As the treatment and outcome of the ALA and PLA differs, determining the etiological agent is crucial.
  
  
  
  All clinically diagnosed ALA patients admitted to the Teaching Hospital (TH) in Jaffna during the study period were included and the clinical features, haematological parameters, and ultrasound scanning findings were obtained. Aspirated pus, blood, and faecal samples from patients were also collected. Pus and faeces were examined microscopically for amoebae. Pus was cultured in Robinson's medium for amoebae, and MacConkey and blood agar for bacterial growth. ELISA kits were used for immunodiagnosis of Entamoeba histolytica infection. DNA was extracted from selected pus samples and amplified using nested PCR and the purified product was sequenced.
  
  
  
  From July 2012 to July 2015, 346 of 367 clinically diagnosed ALA patients admitted to Jaffna Teaching Hospital were enrolled in this study. Almost all patients (98.6%) were males with a history of heavy alcohol consumption (100%). The main clinical features were fever (100%), right hypochodric pain (100%), tender hepatomegaly (90%) and intercostal tenderness (60%). Most patients had leukocytosis (86.7%), elevated ESR (85.8%) and elevated alkaline phosphatase (72.3%). Most of the abscesses were in the right lobe (85.3%) and solitary (76.3%) in nature. Among the 221 (63.87%) drained abscesses, 93.2% were chocolate brown in colour with the mean volume of 41.22 ± 1.16 ml. Only four pus samples (2%) were positive for amoeba by culture and the rest of the pus and faecal samples were negative microscopically and by culture. Furthermore, all pus samples were negative for bacterial growth. Antibody against E. histolytica (99.7%) and the E. histolytica antigen were detected in the pus samples (100%). Moreover, PCR and sequencing confirmed these results.
  
  
  
  To our knowledge, this is the first report from Sri Lanka that provides immunological and molecular confirmation that Entamoeba histolytica is a common cause of liver abscesses in the region.
authors.affiliation: Department of Pathology, Faculty of Medicine, University of Jaffna, Jaffna, Sri Lanka. selvamkannathasan@gmail.com.
authors.forename: Selvam
authors.initials: S
authors.lastname: Kannathasan
authors.affiliation: Department of Pathology, Faculty of Medicine, University of Jaffna, Jaffna, Sri Lanka.
authors.forename: Arumugam
authors.initials: A
authors.lastname: Murugananthan
authors.affiliation: Department of Medicine, Faculty of Medicine, University of Jaffna, Jaffna, Sri Lanka.
authors.forename: Thirunavukarasu
authors.initials: T
authors.lastname: Kumanan
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka.
authors.forename: Devika
authors.initials: D
authors.lastname: Iddawala
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka.
authors.forename: Nilanthi Renuka
authors.initials: NR
authors.lastname: de Silva
authors.affiliation: Coomealla Health Aboriginal Corporation, Dareton, NSW, Australia.
authors.forename: Nadarajah
authors.initials: N
authors.lastname: Rajeshkannan
authors.affiliation: International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
authors.forename: Rashidul
authors.initials: R
authors.lastname: Haque
mesh_terms: D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000032:analysis; D016054:DNA, Protozoan / Q000032:analysis; D004748:Entamoeba histolytica / Q000302:isolation & purification*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008101:Liver Abscess, Amebic / Q000175:diagnosis* / Q000473:pathology*; D008828:Microbiological Techniques; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012698:Serologic Tests / Q000379:methods*; D013188:Sri Lanka
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016054:DNA, Protozoan
keywords: Amoebic liver abscess; Entamoeba histolytica; Northern Sri Lanka