Prevalence and Risk Factors of Intestinal Helminthiasis in Remote Mountainous Villages of Northern Lao PDR: A Cross-Sectional Study

Knowledge, Attitude, and Practice towards Prevention of Intestinal Helminth Infection among Residents of the Ho Municipality in the Volta Region of Ghana

Background

This study investigated the knowledge, attitude, and practices of residents in the Ho municipality towards intestinal helminth infections and their prevention.

Method

A descriptive cross-sectional study involving questionnaire administration was conducted among randomly sampled residents of the Ho municipality of the Volta Region of Ghana. A minimum sample size of 400 was calculated for subjects using Yamane's formula for population. Pearson's chi-square analysis was done to determine any relationship between sociodemographic characteristics and the categories of knowledge, attitude, and practices. Results from data analysis were computed as frequencies and percentages. P < 0.05 is considered statistically significant.

Results

Of the 400 participants, 343 (85.7%) were aware of intestinal helminths, but the majority had poor knowledge of its cause despite 50.5% (202) having good knowledge scores. Most participants (331, 82.8%) had a bad attitude toward preventing the disease. Most (335, 83.8%) of the community members still adhered to the poor practice of open defecation with the excuse of unavailable latrines, and some (143, 35.8%) believe that intestinal helminths are nothing to worry about.

Conclusion

Health education should address the perceptions towards preventing intestinal helminthiasis and be complemented by making available public lavatories in the municipality to curb the unacceptable practice of open defecation.

Intestinal helminth infections and associated risk factors among adults in the Lao People's Democratic Republic

BACKGROUND

Helminthiases are highly endemic in Southeast Asia, including the Lao People's Democratic Republic (Lao PDR). This study aimed to assess the current intestinal helminth infections and the associated risk factors among adults across the Lao PDR.

METHODS

A cross-sectional survey was conducted in 165 villages across 17 provinces and the Vientiane Capital, Lao PDR. A multi-stage sampling method was employed to select the adult study participants (≥ 18 years). Data collection included (1) interview of the study participants, (2) physical measurements, and (3) a five gram of stool sample from each study participant was collected and preserved in 10% formalin solution for intestinal helminth detection using formalin-ether concentration technique (FECT). Descriptive analysis was used to describe the socio-demographic characteristics of study participants and the prevalence of intestinal helminth infections. Logistic regressions were applied to test the association between intestinal helminth infection and individual risk factors. A P-value below 0.05 was considered statistically significant.

RESULTS

A total of 2800 study participants were enrolled. Their average age was 46.0 years; 57.8% were female. Overall, 30.9%, 8.6% and 1.5% of study participants were infected with one, two, or three different intestinal helminth species, respectively. Among the study participants 21.6% were infected with hookworm, 18.8% with Opisthorchis viverrini-like (Ov-like) infection, 4.8% with Strongyloides stercoralis, 2.3% with Ascaris lumbricoides, 1.5% with Trichuris trichiura, and 3.3% with Taenia spp. Ov-like infection was of high prevalence in the southern (28.8%) and central (21.3%) provinces, while hookworm (26.3%), A. lumbricoides (7.3%), T. trichiura (3.1%), and Taenia spp. (4.2%) were prevalent in the northern provinces. Risk analysis showed that men were more likely to be infected with hookworm [adjusted odds ratio (aOR) = 1.2, P = 0.019]. The Lao-Tai ethnic group had a 5.2-times (P < 0.001) higher chance of having Ov-like infection than the minorities. Possession of toilet facility at home was associated with reduced odds for Ov-like (aOR = 0.4, P < 0.001) and hookworm (aOR = 0.6, P < 0.001) infections.

CONCLUSIONS

Our study provides a nationwide update of the intestinal helminth prevalence among adults in Lao PDR. To the best of our knowledge, this is the first Lao nationwide survey on intestinal helminth infections and risk factors in adults. It provides crucial information for national control programs for intestinal helminth infections in Lao PDR.

Prevalence of intestinal parasitic infections and genetic differentiation of Strongyloides stercoralis among migrant workers from Myanmar, Lao PDR and Cambodia in northeastern Thailand

Intestinal parasitic infections (IPIs) remain a public-health problem worldwide, including in countries of the Lower Mekong subregion. Increases in human migration from neighboring countries might cause reemerging parasitic infections, leading to spread of parasites in the landscape. Here, we conducted a cross-sectional study to identify the prevalence of IPIs in migrant workers from Myanmar, Lao PDR, and Cambodia who were dwelling in Nakhon Ratchasima Province, northeastern Thailand. The identification of Strongyloides species and genetic differentiation of worms from migrant workers with different countries of origin was also assessed. Fresh stool samples were collected from 338 migrant workers and examined for evidence of IPIs using agar plate culture (APC) and the formalin-ethyl acetate concentration technique (FECT). Among those nine samples positive for nematodes by APC, the Strongyloides or hookworm species present was confirmed using the polymerase chain reaction (PCR) followed by DNA sequencing. This revealed eight cases of Strongyloides stercoralis infection and one of Necator americanus. Fifty-one out of 338 individuals (15.09%) were positive for IPIs using FECT and APC. Eggs of Opisthorchis-like flukes were the most common parasite (11.83% of samples), followed by S. stercoralis (2.37%), Entamoeba coli (1.50%), hookworm (0.89%), Taenia sp. (0.60%) and Hymenolepis nana (0.30%). The genetic differentiation of S. stercoralis recovered from migrant workers with different countries of origin was analyzed. Specimens of S. stercoralis isolated from workers from Lao PDR, Cambodia and Myanmar were genetically similar to those sequenced from Thailand. However, there were population-genetic differences between S. stercoralis from these Southeast Asian countries and other regions of the world. This study demonstrated that IPIs were prevalent in migrant workers in the northeastern region of Thailand. Our findings provided molecular confirmation of the presence of S. stercoralis and explored the genetic differentiation of S. stercoralis from those infected migrant workers. An effective anti-parasitic drug should be provided for migrant workers and its administration enforced.

Effectiveness of public health interventions in reducing the prevalence of Opisthorchis viverrini: a protocol for systematic review and network meta-analysis

INTRODUCTION

The carcinogenic liver fluke Opisthorchis viverrini is a major public health problem in the Mekong basin region. The liver flukes can induce cholangiocarcinoma, a bile duct cancer that causes a significant burden of mortality and economic loss. Various public health interventions have been conducted to reduce opisthorchiasis but the prevalence of O. viverrini remains high in endemic regions. The aim is to quantify the effectiveness of public health interventions in reducing the prevalence of O. viverrini infection.

METHODS AND ANALYSIS

Seven databases (including PubMed, SCOPUS, Web of Science, EMBASE, ScienceDirect, Thai thesis database and TCI (Thai journals online)) will be searched from initiation through to 2022 to identify studies of interventions to reduce the prevalence of O. viverrini infection. The prevalence, incidence or number of O. viverrini-infected people will be used as the source of O. viverrini prevalence data. A conventional meta-analysis and a Bayesian network meta-analysis will be conducted to undertake direct and indirect comparisons of different interventions. Meta-regression will be used to determine the effect of each intervention. The risk of bias will be assessed using the Cochrane Collaboration's risk of bias tool. Heterogeneity between studies will be determined by forest plots and I2 and publication bias investigated with funnel plots and the Egger's test.

ETHICS AND DISSEMINATION

Ethical approval will not be required because this study will only use published data. The final report of this review will be disseminated through publication in a peer-reviewed scientific journal and will also be presented at relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42022323066.

Current status of human liver fluke infections in the Greater Mekong Subregion

The Greater Mekong Subregion (GMS) is a trans-national region of the Mekong River basin in Southeast Asia comprising Cambodia, the People's Republic of China (specifically Yunnan Province and Guangxi Zhuang Autonomous Region), Lao People's Democratic Republic (Lao PDR), Myanmar, Thailand, and Vietnam home to more than 340 million people or almost 4.5% of the global population. Human liver fluke infections caused by Opisthorchis viverrini and Clonorchis sinensis have been major public health problems in this region for decades. Opisthorchiasis caused by O. viverrini is prevalent in Thailand, Lao PDR, Cambodia and central-southern Vietnam with more than 12 million people infected. Clonorchiasis caused by C. sinensis is endemic in northern Vietnam and Guangxi with estimated 3.5 -5 million infected. The infections can cause several liver and biliary diseases such as cholangitis, periductal fibrosis, gallstones, and cholangiocarcinoma (CCA), a fatal bile duct cancer. Key determinants of the geographical distribution differences of the two liver fluke species are snail species and geographic barriers. Main risk behaviour of the infections is the culture of eating raw fish "the raw attitude" of people in the GMS, especially the Tai/Dai/Thai/Laos ethnic groups, the major population in the GMS. Over the past 20 years, there is a big change in prevalence of the infections. Opisthorchiasis has long been endemic, particularly in northern and northeastern Thailand and Lao PDR with over 8-10 million cases estimated. However, after several rounds of national campaign against opisthorchiasis using integrated control approach in Thailand over the past three decades, the prevalence of O. viverrini infection has reduced from over 15% in 1996 to 2.2% in 2019. High prevalence of O. viverrini infection continues in Lao PDR and central Vietnam. Emerging high prevalence, up to a maximum of 47.5%, has been noted in Cambodia during the past 10 years possibly due to more studies being conducted rather than increasing prevalence. O. viverrini infection has now also been reported in Lower Myanmar in recent years. Clonorchiasis has been known in northern Vietnam and southern China for a long time. Several surveys have reported infections in Guangxi in the last 10 years, and until now liver fluke infected cases have not been reported in Yunnan. Overall, nowadays, there is a shift in high risk areas for GMS liver fluke infection from northeastern Thailand to Lao PDR, Cambodia, Vietnam, Myanmar, and Guangxi P.R. China. Urgent systematic disease mapping and integrated liver fluke control using One Health approaches should be implemented nationwide in GMS countries.