Development of Simple Diagnostic Tests for Antigens/Antibodies relevant to Health Problems in Thailand and Other Countries
Immunochromatographic Test for Rapid Diagnosis of Pythiosis
Pythiosis is a life–threatening infectious disease in both humans and animals living in Asia, the Americas, Africa, and parts of Australia and New Zealand. Human pythiosis is endemic in Thailand where about 80% of the cases are reported. The etiologic pathogen is the fungus–like organism Pythium insidiosum. The disease has high mortality and morbidity rates. Use of antifungal drugs are ineffective against P. insidiosum, leaving radical surgery as the main treatment option. Prompt treatment leads to better prognosis of affected individuals and can be achieved by early and accurate diagnosis. Since pythiosis is being increasingly reported worldwide, there is a need for a rapid, user–friendly, and efficient test that facilitates the diagnosis of the disease.
Figure 1. Hypha of P. insidiosum
Figure 2. Rapid detection of pythiosis
Immunochromatographic tests (ICT) to detect anti–P. insidiosum IgGs in humans and animals were developed. The test is a rapid, user–friendly, and efficient assay for serodiagnosis of pythiosis. The test kit has been mass produced for free distribution to hospitals with medical schools throughout the country. The use of ICT for early diagnosis and monitoring of pythiosis patients helps to save limbs and lives.
These studies were published in international journals and the ICT test kits were also patented:
- A Rapid Multi–Host Specific Immunochromatographic Serodiagnostic Test for Pythiosis. Thailand patent No. 78223, August 27, 2020.
- Development of an Immunochromatographic Test for Rapid Serodiagnosis of Human Pythiosis. Thailand patent No. 78223, March 25, 2019.
Development of Immunochromatographic Test for Rapid Diagnosis of Penicillium marneffei Infection
Penicillium marneffei is classified as an important emerging opportunistic fungal infection. It has been recently renamed as Talaromyces marneffei. It is the most prevalent systemic mycotic infection in patients infected with human immunodeficiency virus (HIV). This infection is endemic in tropical Asia including Thailand, northeastern India, southern China, Hong Kong, Vietnam, and Taiwan. The microorganism is the only known temperature–dependent dimorphic fungus of the genus Penicillium.
A novel inhibition immunochromatographic assay (Inh–ICA strip) for detection of P. marneffei yeast antigens in urine samples has been developed. The system was developed by employing P. marneffei yeast phase specific monoclonal antibody (mAb) and P. marneffei cytoplasmic yeast antigen. The rapid assay showed high specificity, recognizing antigens from P. marneffei only, but not other related antigens of clinically important fungi, including C. albicans, C. neoformans, P. insidiosum, H. capsulatum, Penicillium sp., A. fumigatus, and cytoplasmic mycelium of P. marneffei. The assay was sensitive in detecting the fungal antigen at a concentration as low as 3.125 µg/mL. The test exhibited sensitivity, specificity and accuracy of 87.87%, 100% and 95.5%, respectively. The results showed that the novel Inh–ICA strip can be applied in the diagnosis of P. marneffei infection with an acceptable degree of reliability. This study was published in PLoS One Journal. The Inh–ICT was patented under a title of “A novel immunochromatographic immunodiagnostic test for Penicilliosis marneffei”, Thailand patent No. 78224, August 27, 2020.
Figure 3. The ICT strip components
Rapid Immunochromatographic Test for Diagnosis of Fasciolosis
Fasciolosis is a disease of domestic ruminants, responsible for serious economic loss of cattle, sheep and goats throughout the world. It is caused by Fasciola hepatica and Fasciola gigantica, and is characterized by destruction of the host liver tissue and damage to the bile ducts, with young animals being particularly affected, becoming emaciated and dying. An ICT for detection of fasciolosis has been developed with high sensitivity and specificity, which should be useful for effective treatment and control of this disease.
Figure 4. Immunochromatographic strips
The test kit was patented under a title of “A One–Step Rapid Immunochromatographic (IC) Test for Diagnosis of Fasciolosis Caused by Fasciola gigantica” with Thailand patent No. 63369, August 1, 2018.
Rapid Diagnostic Test to Detect Specific Microbial Nucleotide Sequences
Recently, there is an urgent need for rapid diagnostic tests for new infectious agents in man and animals. Conventionally, these infectious agents are identified either by culture or by using molecular biology techniques, such as PCR. These processes are costly and usually take several hours or even days. We have produced luminol encapsulated biotinylated liposome and used it as a generic signal generator, capable of conjugation to biotinylated biomolecules, such as specific microbial oligonucleotides, antibody and antigen. The system has been used to detect specific oligonucleotide hybridization and specific antigen–antibody interaction, and the result was published in the journal Analytical Sciences.