Cholangiocarcinoma (CCA) is more prevalent in Southeast Asian countries compared to the western world, where cases of CCA are rare. Opisthorchis viverrini (OV) infection (opisthorchiasis) is the associated cause of this increase of cases in CCA, and rates of high infection with OV correlate with high CCA occurrence. In the Northeastern Isaan region of Thailand, OV-infection is endemic – this region also suffers high levels of CCA. OV may be transmitted by eating raw or undercooked fish in foods such as such as ‘koi pla’. After consumption, the OV parasite resides in the duodenum, the liver and surrounding bile ducts and can live for up to 20 years. Infection is asymptomatic, making CCA difficult to detect until it presents in its terminal stages. For these reasons, OV is classed as a type 1 carcinogen.
As part of our integrated masters final year project and internship, Charlotte and I are observing the sustained immune response towards OV – one of several contributors to the development of CCA. As part of a Newton Fund project funded by the British Council, we have been conducting our research in the Tropical Disease Research Laboratory (TDRL), part of Khon Kaen University. So far, we have enjoyed integrating ourselves into a completely new culture and working in a lab with more independence than we have had before. So far it has been an exciting and rewarding experience. TDRL provides a lot of opportunities for international students, so whilst we are submerged in Thai culture we have also been fortunate to meet people from all across the world. This is in addition to making discoveries along the way in the lab. Knowing that our research will contribute towards efforts to reducing OV-infection and CCA mortalities is very humbling.
TDRL developed the “Lawa Model” several years ago and introduced this to Lawa villages 6 years ago. This model aims to educate people about the dangers of OV and eating potentially contaminated fish. Health volunteers are responsible for screening of patients to detect OV and administering praziquantel, as well as other non-OV health issues. They are also required to examine stool samples and educate locals as part of the free education programme in local schools, or ‘door to door’ educating. The health volunteers are key in maintaining the health and awareness of the local communities, whether it be through interpretive dance, adaptations of popular Thai songs or handing out leaflets.
The Lawa Model education programme in schools is free. Before the model was introduced, an average of 10% of children were OV-positive. Now, most schools around the Lawa Region can boast 0% infection. The Model encourages education about OV as part of the school curriculum by rewarding them with certificates. This is promising for future generations that are much less likely to suffer from CCA.
The Lawa Model adopts the ‘EcoHealth’ approach which means a transdisciplinary approach, where experts from different scientific disciplines such as conchology, ichthyology, parasitology, biochemistry and veterinary medicine that target each stage of OV’s lifecycle. A major failing in previous attempts has been lack of sustained awareness and implementation of control programmes. The Lawa Model has attempted to solve this by encouraging and educating stake holders including local officials, monks, village leaders, schools and the previously mentioned health volunteers who are also responsible for providing regular health checkups for the villagers and checking for OV-infection.
On our visit to Lawa Lake, we saw for ourselves the success of the model, where it was very clear that the majority of people now had a clear understanding of how OV is transmitted. Before the model was introduced six years ago, OV-infection in the human populations in this area was 60%, but this has now fallen to less than 10%. OV-infection in fish has fallen from 70% to <1% and snails infected with OV have dropped to less than 0.2%. As a result of this success, the TDR team are now planning to introduce the Lawa Model into different provinces within Thailand and other neighbouring countries. Charlotte and I recently visited Kalasin, a province nearby to Khon Kaen, which is in very early stages of Lawa Model implementation. It was very eye-opening to see how unaware some people still are in Thailand despite the threat of this disease. However, due to the Lawa Model’s previous success it is likely villages in Kalasin will have the same promising results.
The TDR team from KKU often travels to local Lawa Villages to hold talks about the dangers of OV and explain how it is transmitted. Ultrasound screening is also performed to determine levels of liver complication in patients. Blood samples are also taken from the field and used as part of research about the pathology of OV infection, which precedes CCA. As part of my and Charlotte’s research, we have analysed these blood samples through various immunological assays. Our research will contribute to the current hypothesis that people with a more aggressive immune response are more susceptible to the development of CCA.
The recent ‘National agenda against liver fluke and cancer’ has made clear its aim to remove OV from Thailand in the next 10 years and reduce the number of CCA mortalities. The Lawa Model is a perfect example of how constant attention and support to communities can reduce the infection rate of OV. For this to happen on a national scale, the government must become involved on a permanent level to guarantee replication of the Lawa Model’s success.
After 3 months here, Charlotte and I are continuing to enjoy both the science and the fun that comes with Thai culture. We are fortunate to be part of such a worthwhile project and hope our time here will be beneficial to both ourselves, and the fight against OV and CCA.
Top L-R: Dr Kanin Salao and Eddy processing patient blood samples in the lab; Eddy and Charlotte with Prof Steven Edwards and Dr Helen Wright, who lead the University of Liverpool collaboration with TDRL, and Dr Kanin Salao from TDRL prior to them leaving for Khon Kaen in July; Eddy and Charlotte with other TDRL students paying respects to Prof Banchob Sripa (centre) on “Teachers Day”.
Bottom L-R: Community outreach program in Kalasin; Charlotte carrying out neutrophil isolations in the lab; OV parasite under the microscope.