Amebic liver abscess (ALA), caused by Entamoeba histolytica, is the most common extraintestinal manifestation of amebiasis. However, in contemporary clinical practice, diagnosis increasingly relies on serology and polymerase chain reaction (PCR), whereas direct microscopic identification of motile trophozoites in aspirated specimens has become rarely documented. Furthermore, optimal management necessitates complete anti-amebic therapy covering both invasive tissue stages and luminal intestinal colonization to prevent relapse. Here, we report a case of a 25-year-old male with a history of splenectomy and pulmonary tuberculosis, presenting with fever, right upper quadrant pain, and cough. Imaging revealed a right hepatic lobe abscess. While abscess and blood cultures remained sterile, sputum culture grew E. coli. Fresh microscopic examination of the aspirate readily demonstrated motile, erythrophagocytic trophozoites, subsequently confirmed as E. histolytica by sequencing. Although the patient showed initial clinical improvement with metronidazole, he later developed severe bleeding and ulceration of the ascending colon, ultimately requiring partial colectomy. This case underscores the enduring diagnostic value of conventional wet-mount microscopy in the molecular era, offering a rapid and cost-effective tool. Critically, it also highlights a key therapeutic principle ALA treated with a tissue-active agent must be followed by a luminal agent to eradicate intestinal carriage. Failure to do so risks persistent colonic disease, severe complications, or treatment failure, as observed in this patient.

Lymphogranuloma venereum (LGV) caused by Chlamydia trachomatis (CT) serovars L1-L3 has re-emerged among men who have sex with men (MSM), predominantly manifesting as anorectal disease. Oropharyngeal LGV remains poorly characterized, with only sporadic case reports in Western countries. Although CT genovariant L2b has been detected in an oropharyngeal specimen through surveillance in Taiwan, the clinical features of oropharyngeal LGV have not been described in Asia. We report two MSM living with HIV in Taiwan with oropharyngeal LGV. Case 1 was a 32-year-old asymptomatic patient and CT was identified through routine multi-site screening prompted by a rising rapid plasma reagin (RPR) titer. LGV was detected only at the oropharyngeal site, with a negative rectal specimen. Case 2, a 51-year-old man, presented with small oral ulcers resembling aphthous stomatitis, along with anorectal symptoms and amoebic liver abscess. Genovariant L2b was confirmed in both oropharyngeal and rectal specimens by ompA sequencing. In both cases, Treponema pallidum PCR on oropharyngeal specimens was negative despite elevated RPR titers. Case 1 received doxycycline 100 mg twice daily for 7 days for asymptomatic LGV carriage, while Case 2 received a 21-days course for symptomatic infection. Case 1 achieved microbiological cure confirmed by follow-up PCR testing. Case 2 demonstrated resolution of oral and anorectal symptoms, with microbiological cure confirmed at follow-up. These cases illustrate that oropharyngeal LGV may be asymptomatic or mimic common oral conditions. Multi-site CT testing and ompA genotyping should be considered in MSM with suspected STI, even in the absence of typical anorectal symptoms.

Hepatic actinomycosis is an uncommon diagnostic mimic of pyogenic or amoebic liver abscess. A 34-year-old healthy man presented with fever, vomiting, and right upper quadrant pain after recent travel. Computed tomography showed a 7 x 7 x 5 cm subcapsular segment VIII hepatic abscess. Empirical piperacillin-tazobactam and metronidazole were started, followed by ultrasound-guided drainage with catheter placement. Blood cultures grew Actinomyces odontolyticus, and the abscess aspirate grew Streptococcus intermedius, supporting a mixed actinomycotic-pyogenic abscess rather than incidental bacteremia. Low-titer Entamoeba histolytica serology was not considered clinically significant. The Actinomyces isolate showed intermediate susceptibility to penicillin and resistance to clindamycin. After a partial response to amoxicillin-clavulanate, therapy was changed to doxycycline with serial ultrasound surveillance showing interval cavity regression. The case emphasizes contextual interpretation of Actinomyces bacteremia, early source control, and susceptibility-guided prolonged therapy.

Blastocystis hominis is a ubiquitous intestinal parasite commonly detected in human stools. Queries about the pathogenic nature of B. hominis in immunocompetent individuals have been raised with conflicting reports about the clinical significance of detecting the parasites in various specimens. Reports have documented invasive intestinal infections and the detection of Blastocystis species in both a splenic cyst and a hepatic abscess. We present the case of a 65-year-old man with a history of recent travel to a tropical country who was found to have multiple hepatic abscesses. Analysis of the hepatic abscess fluid confirmed the presence of Entamoeba histolytica and Blastocystis species, and, to our knowledge, this is the second reported case of the same findings. Overall, the clinical and microbiological picture was most consistent with amoebic liver abscess secondary to E. histolytica; however, the presence of Blastocystis species introduces uncertainty around its clinical significance. Further studies are required to investigate the pathogenicity of Blastocystis species, including molecular investigations into the various genetic subtypes.

Hepatic abscess (HA) poses a diagnostic challenge worldwide, with up to around 80% of cases initially missed in emergency settings. This can be attributed to their clinical and imaging appearance varying considerably depending on the underlying pathogen and abscess type. Computed tomography (CT) remains the primary imaging modality for evaluation, and this pictorial essay highlights the characteristic imaging features of the subtypes of HA which include pyogenic, amebic, fungal, and hydatid infections. Key imaging findings discussed include the cluster sign and double target sign in pyogenic abscesses, the solitary right subcapsular morphology of amebic abscesses, the disseminated microabscess pattern of fungal infections in immunocompromised hosts, and the daughter cysts with peripheral calcifications characteristic of hydatid disease. Furthermore, HA has neoplastic mimickers which can demonstrate similar imaging characteristics. The diagnosis is further complicated as patients with known malignancies or surgical intervention are prone to developing HA. This pictorial review highlights the key imaging features that enable radiologists to recognize HA on CT in emergency settings and differentiate it from its most clinically significant mimics.

Hepatic melioidosis is a clinically significant manifestation of Burkholderia pseudomallei infection, increasingly recognised across South and Southeast Asia. It primarily affects diabetic and immunocompromised individuals and is characterised by a subacute to chronic presentation that often mimics other causes of liver abscess. The pathogenesis of hepatic melioidosis reflects the interplay between bacterial virulence mechanisms and impaired host immunity, leading to intracellular persistence and necrotising hepatic lesions. Characteristic imaging features, including the honeycomb and necklace signs, aid in distinguishing melioidosis from pyogenic or amoebic abscesses. Microbiological confirmation remains the diagnostic gold standard but is frequently delayed by misidentification in automated systems. Management requires an intensive phase with intravenous ceftazidime or carbapenems, followed by an eradication phase with trimethoprim-sulfamethoxazole. Drainage is reserved for large, multiloculated abscesses or those that are poorly responsive to antibiotics. Hepatic melioidosis, though underdiagnosed, is an important cause of hepatic abscess in endemic regions. Awareness of its distinctive clinical, radiologic, and microbiologic features is essential for timely diagnosis and optimal management. Strengthening laboratory capacity and clinician familiarity can reduce misdiagnosis, guide appropriate therapy, and improve patient outcomes.

Entamoeba histolytica is a protozoan parasite that causes amebic colitis, a leading cause of severe diarrheal disease worldwide, and amebic liver abscess, the most common extraintestinal manifestation of infection. The disease burden is highest in resource-limited settings but remains clinically important in travelers and men who have sex with men in non-endemic regions. Although most infections are asymptomatic, severe and fulminant disease is associated with high mortality, particularly among individuals exposed to corticosteroids or other forms of immunosuppression. The increasing use of molecular diagnostic tools has improved understanding of the epidemiology of E. histolytica and enabled distinction from morphologically identical but nonpathogenic Entamoeba species; however, these diagnostics remain underutilized in many endemic settings due to cost and infrastructure limitations. Treatment options remain limited, with nitroimidazoles constituting the only drug class available for symptomatic invasive disease, leaving few alternatives for patients who cannot tolerate therapy or in the event of emerging resistance. Despite advances in understanding parasite pathogenesis and the application of high-throughput technologies, no licensed vaccine exists, and progress toward vaccine development has been minimal. These persistent gaps highlight the need to reprioritize amebiasis as a neglected tropical disease and to accelerate investment in diagnostics, therapeutics, and preventive strategies.

The development of effective vaccines against Entamoeba histolytica remains a major challenge, particularly for preventing amoebic liver abscess (ALA). In this study, carbon nanotubes (CNTs) were evaluated as nanocarriers through bioconjugation with L220-derived peptides (PL220-CNTs). CNTs were synthesized, purified, and characterized, confirming successful bioconjugation (42%). In vitro, PL220-CNTs exhibited negligible cytotoxicity in J774 macrophages and induced morphological changes characterized by cytoplasmic prolongations and phagosome-like structures. In vivo, subcutaneous immunization of hamsters induced antigen-specific responses, including splenocyte proliferation and increased IL-17A production, suggesting the participation of an IL-17A-associated immune response. Notably, animals immunized with PL220-CNTs exhibited limited antibody production against L220-derived peptides, suggesting a predominantly cellular immune response. PL220-CNT immunization conferred complete protection against ALA following intrahepatic challenge, whereas L220 alone provided partial protection. Histological analyses revealed preservation of hepatic architecture and reduced inflammatory damage in PL220-CNT-immunized animals. Overall, these findings support the potential of bioconjugated CNTs as immunomodulatory nanoplatforms for vaccine development against amoebiasis and other infectious diseases.

Amoebic infections of the brain can cause brain abscesses and meningoencephalitis. Brain abscess is a rare form of extraintestinal amoebiasis caused by hematogenous spread from intestinal infection with Entamoeba histolytica, which occurs through oral intake of contaminated water and food or fecal-oral transmission. It is mostly associated with amoebic liver abscesses and can be effectively treated with metronidazole. Meningoencephalitis caused by pathogenic free-living amoebae is extremely rare. Primary amoebic meningoencephalitis (PAM), caused by Naegleria fowleri infection of the olfactory epithelium with direct intracranial spread via the fila olfactoriae, primarily affects healthy young individuals through exposure to freshwater or brackish water in swimming pools, rivers, ponds, lakes, and estuaries. Granulomatous amoebic meningoencephalitis (GAM) results from the hematogenous spread of extracranial infectious foci caused by Acanthamoeba species or Balamuthia mandrillaris. Acanthamoeba-related GAM is more common in immunocompromised individuals, and waterborne transmission is relatively frequent. Balamuthia mandrillaris-related GAM can affect both immunocompromised and immunocompetent individuals, often affecting people in their 50s to 70s with underlying conditions, such as malignancies, diabetes, and chronic kidney disease, with soil-borne transmission being more common. Both PAM and GAM have high mortality rates, and effective treatments are yet to be established.

Disseminated amoebiasis in pregnancy, though rare, can be life-threatening and mimic bacterial sepsis or inflammatory bowel disease (IBD). We report a case of maternal near-miss at 18 weeks of gestation due to amoebic colitis and liver abscess. The woman presented with fever, bloody diarrhoea, and abdominal pain, initially suspected to be bacterial sepsis, and treated with ceftriaxone. Ultrasound revealed hepatic abscesses and caecal thickening. Following massive rectal bleeding and hypovolemic shock, colonoscopy confirmed Entamoeba histolytica infection. Liver abscess drainage yielded anchovy-sauce pus, and stool, blood, and aspirate cultures were negative. Metronidazole therapy led to clinical improvement. This case highlights the importance of considering disseminated amoebiasis in pregnant women with haemorrhagic diarrhoea and sepsis. Early histopathological confirmation and targeted anti-amoebic therapy are essential for effective management, preventing severe complications such as haemorrhagic shock and liver abscess.

Amoebic liver abscess (ALA) is often associated with significant complications. Contemporary prospective data comprehensively characterizing complicated and uncomplicated ALA are limited. This prospective cohort study followed 150 patients with ALA and found that 60.7% experienced at least one complication. The significant complications were peritoneal rupture, pleural rupture, venous thrombosis, biliary fistula, secondary bacterial infection, and organ dysfunction. Patients with complicated ALA had larger abscesses, higher inflammatory markers, and greater liver dysfunction than those without complications. The types of complications were influenced by the location of the ALA. Additionally, subcapsular abscesses and lower baseline HDL-cholesterol levels were independently linked to complicated cases of ALA. Although complications were common, both groups showed favourable outcomes. Mortality was 2%, occurring only in the complicated group. At three months, both groups had comparable rates of symptom resolution, cavity disappearance, and relapse.

Amoebiasis, a gastrointestinal infection caused by Entamoeba histolytica, is the third leading cause of mortality worldwide among parasitic infections with over 100,000 deaths annually. Apart from dysentery, it can manifest as extraintestinal disease, most commonly liver abscess, and rarely pulmonary, cardiac, and brain involvement. This case demonstrates the challenging management of a complicated amoebic liver abscess (ALA) with pulmonary involvement and venous thromboembolism. A 26-year-old male presenting with pleuritic right hypochondriac pain, fever, and dyspnoea underwent hepatobiliary ultrasonography (US) which showed a liver abscess. Computed tomography (CT) of the thorax and abdomen revealed a ruptured right liver abscess with infra-diaphragmatic intrathoracic extension and right lung empyema with the presence of inferior vena cava (IVC) and right hepatic vein thrombosis, and right pulmonary embolism. He underwent placement of a percutaneous pigtail thoracostomy catheter for drainage of right lung empyema which was complicated with a bronchopleural fistula. Amoebiasis serology was later reported positive for immunoglobulin G (IgG). The patient was treated with medical therapy which included tissue and luminal amebicides and warfarin. Video-assisted thoracoscopy surgery (VATS) was performed to visualize and repair the bronchopleural fistula. Follow-up CT revealed significant reduction in size of the right lateral intrathoracic and liver abscess. This case underscores the importance of awareness of pulmonary involvement in ALA and the associated risk of venous thromboembolism as early detection facilitates effective management and reduces mortality.