Prevalence and Associated Risk Factors of Opisthorchis Viverrini Infections in Rural Communities Along the Nam Kam River of Northeastern Thailand
Total Page：16
File Type：pdf, Size：1020Kb
Tropical Biomedicine 36(1): 81–93 (2019) Prevalence and associated risk factors of Opisthorchis viverrini infections in rural communities along the Nam Kam River of Northeastern Thailand Chuangchaiya, S.1*, Laoprom, N.2 and Idris, Z.M.3* 1Faculty of Public Health, Kasetsart University, Chalermphrakiat Sakon Nakhon Province Campus, 47000, Sakon Nakhon, Thailand 2Faculty of Science and Engineering, Kasetsart University, Chalermphrakiat Sakon Nakhon Province Campus, 47000, Sakon Nakhon, Thailand 3Department of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000, Kuala Lumpur, Malaysia *Corresponding author e-mail: [email protected]; [email protected] Received 4 May 2018; received in revised form 26 November 2018; accepted 27 November 2018 Abstract. Opisthorchis viverrini infection is still one of the public health problems in Southeast Asia. In Thailand alone, more than three million people are estimated to be currently infected. Opisthorchiasis may cause severe biliary diseases, eventually leading to fatal cholangiocarcinoma. This study aimed to investigate the prevalence and risk factors of opisthorchiasis in two rural communities along the Nam Kam River in the northeastern region of Thailand. A cross-sectional study was conducted in Phon Na Kaeo District of Sakon Nakhon Province and That Phanom District of Nakhon Phanom Province in Thailand between March and June 2017. Faecal samples were collected and examined for the presence of O. viverrini by Kato-Katz technique. Socio-demographic variables and risk factors were collected by a standardised questionnaire. The overall prevalence of O. viverrini among 495 study participants was 15.4% (95% confidence interval [CI] 12.3 – 18.8). The parasite rate was higher in Nakhon Phanom than in Sakon Nakhon (P = 0.009) and differed significantly in adults <45 years old in both provinces (P <0.05). Multivariate regression analyses revealed being labourer (adjusted odd ratio [AOR] 4.7 [95% CI 1.08, 20.38], P = 0.039) and farmer (AOR 5.79 [95% CI 1.45, 31.91], P = 0.015) were positively associated with a higher risk of O. viverrini infection. This study highlights O. viverrini infection as a significant endemic disease with potential health problems among the water-based communities along the Nam Kam River. For country with high O. viverrini transmission, such information will be useful for designing efficient strategic interventions. INTRODUCTION Thailand are the most effected with O. viverrini infections, where infection Opisthorchis viverrini, a fish-borne prevalence exceeding 50% at the village level trematode, is one of the neglected tropical is still commonly observed (Sithithaworn et diseases with considerable public health al., 2012; Sripa et al., 2015). The concentrated importance in Southeast Asia, particularly in distribution of O. viverrini in these regions Thailand (Keiser & Utzinger, 2009; Sripa et corresponds with the local presence of al., 2010; Utzinger et al., 2010). It has been natural intermediate hosts and the traditional estimated that more than 3.3 million people eating habits (Sriamporn et al., 2004; Sripa et in Thailand are infected with O. viverrini al., 2007). Apart from the northern areas, O. with varying distribution depending on the viverrini infection is also endemic in central endemic areas (Wongsaroj et al., 2014). Rural Thailand due to the migration of local people communities in north and northeastern from the northeastern provinces which 81 maintained their traditional life style that also among communities has led to the includes raw food consumption (Rangsin et persistence of O. viverrini infections in al., 2009; Suwannahitatorn et al., 2013). many parts of these regions (Sripa et al., The life cycle of O. viverrini is complex, 2011; Sithithaworn et al., 2014). involving two intermediate hosts: snails of This study was conducted in two districts the genus Bithynia are the first intermediate along the Nam Kam River namely Phon Na host, whereas freshwater fishes i.e. Cyprinoid Kaeo and That Phanom, in Sakon Nakhon family serve as the second intermediate host Province and Nakhon Phanom Province (Keiser & Utzinger, 2009). Human is infected respectively. Both provinces are situated in by O. viverrini through consumption of raw the northeastern region of Thailand or insufficiently cooked freshwater fish that approximately 500 km from the Thai capital harbours the infective stage of the parasites Bangkok. Phon Na Kaeo District (352 km2) is called metacercariae. Consumption of located at the downstream of the Nam Kam undercooked fish dishes such as Koi pla is River, while That Phanom District (368 km2) deeply rooted in local culture in the affected is about 80 km upstream of Phon Na Kaeo. areas, where proper sanitation is minimal or The Nam Kam River is one of the Mekong absent (Utzinger et al., 2010). Transmission River’s tributaries which cover 3,440 km2 of is maintained by the frequent practice of open catchment area with a total length of 123 km. defecation that results in contamination of The river flows through two provinces water bodies. Although infection with O. starting from Nhong Harn swamp in Muang viverrini is often asymptomatic, chronic District of Sakon Nakhon and merges with infection may lead to a number of severe liver the great Mekong River in That Phanom and bile duct diseases (Mairiang & Mairiang, District in Nakhon Phanom. This river 2003; Keiser & Utzinger, 2009; Sripa et al., provides the water source for agriculture and 2010). The most severe sequelae of O. for various utilities in this region. Though viverrini infection is cholangiocarcinoma there are many developmental initiatives in (CCA), a bile duct cancer with extremely this region, poverty is still a major challenge. poor prognosis (Sripa et al., 2010; Sripa et Farming and fishing are the predominant al., 2011) and with high fatality rate economic activities for the river shore (Sithithaworn et al., 2014). In Thailand, communities. Farming is mostly subsistence- previous studies have reported a high based, particularly rice cultivation as well incidence rate of CCA in the northeastern as small-scale animal husbandry. Fishing is regions ranging from 93.8 to 317.6 per 100,000 done primarily by men in a variety of person-years (Sripa et al., 2007). freshwater bodies including rivers, swamps Today, preventive chemotherapy and paddy fields. Dietary habits are deeply combined with health education via vertical rooted in the local culture and include a programmes remain the main strategy for variety of meals and dishes putatively O. viverrini control in Thailand. It is containing metacercariae. implemented locally in target areas Previous epidemiological studies depending on problems and priorities in each conducted in seven Upper Northeastern community (Jongsuksuntigul & Imsomboon, provinces in Thailand showed that the 2003). Although most target areas are located prevalence of O. viverrini varied among in the northern and northeast regions which provinces: highest in Nakhon Phanom have been recognized as endemic area of (40.9%), followed by Sakon Nakhon (~28%) O. viverrini infection, many reports showed and lowest in Bueng Kan (~10%) that the prevalence was still high (Andrews (Thaewnongiew et al., 2014). Nevertheless, et al., 2008; Ong et al., 2016; Kim et al., 2017; according to the Province Statistic and Saenna et al., 2017). In addition, despite Demographic Office, the total prevalence of decades of control efforts, the high Opisthorchis infections in Nakhon Phanom availability of freshwater fish as major source in 2016 and Sakon Nakhon in 2015 were lower of protein (Grundy-Warr et al., 2012), and the than previously reported with 10.1% and continuous practice of raw fish consumption 11.2%, respectively. These contrasting figures 82 implied that either intensive control A witness observing this procedure also measures of Opisthorchis infections by the signed the consent form. For illiterate health authority might have significant participant, informed consent was read out impact in the reduction of the infections or and, after approval, the person signed with a the overestimation of the true burden of O. fingerprint. No children were involved in this viverrini in the study area. Furthermore, study. there is a dearth of information on the risk factors underlying each study area. The Study design and field procedure critical risk factors for O. viverrini infection A community-based survey was carried out are mainly associated with eating raw fish or between March and June, 2017. Two villages uncooked fish. Differences in education, namely Ban Phon Khae Noi in Sakon Nakhon economy, social practices and life style Province (Na Tong Watthana sub-district, amongst community has been found to Phon Na Kaew District) and Ban Fang Daeng influence the habit of consuming in Nakhon Phanom Province (Fang Daeng inadequately cooked fish (Sripa et al., 2017). sub-district, That Phanom District), were In response, we aimed to investigate the included in the study. These villages were current prevalence and associated risk selected based on, (i) their representa- factors of O. viverrrini infections using faecal tiveness of typical lowland villages samples from people living in Phon Na Kaeo characterised by the proximity of water- and That Phanom, in Sakon Nakhon Province bodies from which freshwater fish can be and Nakhon Phanom Province, respectively. caught; (ii) maintenance of the tradition of Results from this study provide valuable eating