Acanthamoeba in Southeast Asia – Overview and Challenges

Abstract

Acanthamoeba, one of free-living amoebae (FLA), remains a high risk of direct contact with this protozoan parasite which is ubiquitous in nature and man-made environment. This pathogenic FLA can cause sight-threatening amoebic keratitis (AK) and fatal granulomatous amoebic encephalitis (GAE) though these cases may not commonly be reported in our clinical settings. Acanthamoeba has been detected from different environmental sources namely; soil, water, hot-spring, swimming pool, air-conditioner, or contact lens storage cases. The identification of Acanthamoeba is based on morphological appearance and molecular techniques using PCR and DNA sequencing for clinico-epidemiological purposes. Recent treatments have long been ineffective against Acanthamoeba cyst, novel anti-Acanthamoeba agents have therefore been extensively investigated. There are efforts to utilize synthetic chemicals, lead compounds from medicinal plant extracts, and animal products to combat Acanthamoeba infection. Applied nanotechnology, an advanced technology, has shown to enhance the anti-Acanthamoeba activity in the encapsulated nanoparticles leading to new therapeutic options. This review attempts to provide an overview of the available data and studies on the occurrence of pathogenic Acanthamoeba among the Association of Southeast Asian Nations (ASEAN) members with the aim of identifying some potential contributing factors such as distribution, demographic profile of the patients, possible source of the parasite, mode of transmission and treatment. Further, this review attempts to provide future direction for prevention and control of the Acanthamoeba infection.

Potential anti-Acanthamoeba and anti-adhesion activities of Annona muricata and Combretum trifoliatum extracts and their synergistic effects in combination with chlorhexidine against Acanthamoeba triangularis trophozoites and cysts

“…Infection caused by Acanthamoeba spp., free-living protozoa, has been concerned worldwide. Acanthamoeba triangularis (A. triangularis) is a causal agent of human disorders, such as granulomatous amebic encephalitis and Acanthamoeba keratitis (Jercic et al, 2019;Bunsuwansakul et al, 2019). Two stages of Acanthamoeba growth are well known and these include trophozoites and cysts.…”

Effectiveness and Safety of Topical Chlorhexidine and Vitamin E TPGS in the Treatment of Acanthamoeba Keratitis: A Survey on 29 Cases

“…However, the increasing use of contact lenses justifies the growth of incidence/year of AK over time. A compromised immune system also increases the risk, whereas no sex predilection has been reported [ 7 ].…”

Anti-Acanthamoeba synergistic effect of chlorhexidine and Garcinia mangostana extract or α-mangostin against Acanthamoeba triangularis trophozoite and cyst forms

“…3 ) which might be due to the decreased the decreased effect of the extract and α-mangostin. In addition, the cyst form is a is a dormant stage against severe condition, including the presence of anti- Acanthamoeba agents 29 . Overall, this study therefore suggests that the extract and α-mangostin are promising agents that shows the remarkable effects against A. triangularis infections.…”