Amoebic liver abscess in northern Sri Lanka: first report of immunological and molecular confirmation of aetiology

Abstract

BackgroundSince 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.MethodsAll 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.ResultsFrom 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.ConclusionTo 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.

Entamoeba histolytica and amoebic liver abscess in northern Sri Lanka: a public health problem

“…In 2015, it was reported to be 3.0 per 10,000 admissions at THJ, highlighting that this region of the island is still largely endemic to E. histolytica [6]. In a longitudinal study, Kannathasan et al reported 346 confirmed ALA cases in northern SLK over a 3-year period, with 99.7% of serum samples testing positive for the IgG antibody against E. histolytica [48]. While no current data exists on other parts of the island, an early study by Rajasuriya and Nagaratnam (1962) reported 1.5% of total admissions at the General Hospital Colombo, the capital city, are due to ALA [7].…”

“…Additionally, distinguishing ALA from pyogenic liver abscesses (PLA) is crucial due to the differential approach to management in both conditions (see Table 1), despite similar clinical presentation (pyrexia, RUQ pain, hepatomegaly) [48]. While clinical findings alone may be insufficient to distinguish between PLA and ALA [93], certain clinical features can aid in differentiating the two.…”

“…The use of PCR and immunological/molecular profiling for E. histolytica is seldom used in SLK. Indeed, the first published report providing immunological and molecular evidence that E. histolytica as a significant cause of liver abscesses in northern Sri Lanka was in 2018 by Kannathasan and colleagues [48]. In this 3-year study, the authors employed nested PCR from DNA of 50 aspirated pus samples based on the serine-rich E. histolytica protein (SREHP) coding gene.…”

The iron and testosterone levels in amoebic liver abscess patients - a preliminary study from northern Sri Lanka

“…5 Entamoeba histolytica was recently confirmed as a common cause of these clinically diagnosed liver abscesses in northern Sri Lanka. 6 Several factors have been postulated to play a role in the development of ALA in adult males who consume locally brewed beverages. The contributory role of alcohol-induced hepatic iron stores and the male hormone testosterone have been suggested as playing an important role in the pathogenesis of ALA. 7 Although human studies are lacking, testosterone level determines susceptibility to ALA in mouse models.…”

Liver abscess: demographic, clinical, biochemical, imaging and microbial spectrum

“…In recent years, clinically diagnosed ALA has been emerged one of the two most important parasitological public health problems (second only to malaria) in Jaffna, northern Sri Lanka. [11][12][13] Amebae establish hepatic infection by ascending the portal venous system. 14 Clinically; both types of liver abscesses usually present with similar picture ranging from malaise to fever, chills, abdominal pain, and vomiting.…”