Diagnostic tools for human opisthorchaisis

Abstract

Liver flukes of the family Opisthorchiidae consist of three medically important species, namely

Clonorchis

sinensis, Opisthorchis felineus and Opisthorchis viverrini.

These liver flukes infect at least 40 million people and

estimated 700 million people worldwide are at risk of being infected. Of the three currently recognized species, only

O. viverrini

is classified as a type 1 carcinogen because of its role as an initiator of chronic inflammation leading

to subsequent development of cholangiocarcinoma (CCA). At present, there is no early diagnosis of CCA,

the patients usually come to the doctor with advanced stages and die within 3 - 6 months. Importantly, this species

of liver fluke is most commonly found in Southeast Asia. Especially, an estimated 9 million people are infected

in Thailand, that the cost of treatment of opisthorchiasis is approximately $120 million dollars annually for lost

wages and medical care. High accuracy and sensitivity diagnostic methods are therefore required for efficient

control, prevention and treatment of opisthorchiasis. To date, there are three main methods for opisthorchiasis

diagnosis, i.e. parasitological method, which is standard method for microscopy-based identification of diagnosis

stage such as egg in fecal sample. However, its sensitivity and specificity are low due to limitations of skill

and expert of distinguishing egg morphology. Thus, immunological methods and molecular methods to identify

the opisthorchiasis were developed to improve sensitivity and specificity of diagnostic tools. This review article

aims to compile all opisthorchiasis diagnostic methods in order to obtain the suitable guideline for the effective

diagnosis of opisthorchiasis.