Incidence and Re-infection Rates of Opisthorchis viverrini in Upper Northeastern Communities of Thailand

Abstract

Opisthorchis viverrini prevention and control is a basic measure in reducing the incidence long term cholangiocarcinoma. To evaluate the impact of opisthorchis viverrini prevention and control toward temporary epidemiology of parasitic infection, this research aim to investigate incidence, re-infection rates and risk factors of Opisthorchis viverrini in upper Northeastern, Thailand. There were 2,674 people in 7 provinces which were Udonthani, Nhongbualumpu, Loei, Nhongkhai, Bhungkarn, Sakolnakorn and Nakorn Phanom received praziquantel for Opisthorchis viverrini before in 2013. Those people had stool examination by the method of Modified Kato Thick Smear Technique. The prevalence was at 14.3% and the highest was at Nakorn Phanom (28.6%). Opisthorchis incidence in 2014 – 2013 was at 9.0% (95% CI = 0.08-0.10). The highest of incidence was in Nakornphanom which was at (15.0%, 95% CI = 0.12-0.19). The second position was at Sakolnakorn (10.6%, 95% CI = 0.07-0.14) and Udornthani (10.1%, 95% CI = 0.06-0.12) respectively. The re-infection rate of Opisthorchis viverrini was at 5.3%. The risk factors associated with aspects were, history eating raw fish (OR= 3.2, 95% CI= 2.25 - 4.68), having taken praziquantel (OR= 3.1, 95% CI= 2.07-4.58), and the location of some provinces such as Nakornphanom, Sakolnakorn, Nhongkhai and Loei. Thus, the most risk area should be mainly focused. For instance, high quality diagnosis is required to provide medicine and continuously persuade the people not to eat raw fishes.