A cross-sectional study on intestinal parasitic infections in rural communities, northeast Thailand

Misclassification of Opisthorchis viverrini and Minute Intestinal Fluke Eggs by Routine Laboratory Staff Using Images from the Kato-Katz Method

BACKGROUND

The Kato-Katz method is a commonly used diagnostic tool for helminth infections, particularly in field studies. This method can yield inaccurate results when samples contain eggs that are similar in appearance, such as Minute Intestinal Fluke (MIF) and Opisthorchis viverrini (OV) eggs. The close resemblance of eggs can be problematic and raises the possibility of false diagnoses. The objectives were to compare the diagnostic performance of the Kato-Katz method for accurately identifying MIF and OV and to provide evidence of possible misclassification.  Methods: Based on questionnaire responses from 15 (young parasitologists and public health staff), the test comprised 50 MIF egg images and 50 OV egg images, for a total of 100 Google Form questionnaires.

RESULTS

The morphology of MIF and OV eggs found size and shape similarity and found that the shoulder rims were small, while the OV egg found the knobs had disappeared. The opercular conjunction was apparent, the shoulder rims and miricidium were prominent. The average percentage of correctly classified infections was 61.6 ± 12.1%. The accuracy percentages for both public health staff and young parasitologists in identifying were found to be 59.0 ± 14.8 and 66.8 ± 2.8, respectively. There was no significant difference observed in both groups.

CONCLUSION

These findings highlight the need for improving the accuracy of parasite identification. Preserving stool samples before the Kato-Katz method can help mitigate the potential degradation or distortion of parasite eggs. The incorrect classification of both eggs had an impact on treatment plans and the policy of parasite control programs.

Current prevalence and geographic distribution of helminth infections in the parasitic endemic areas of rural Northeastern Thailand

BACKGROUND

Helminth infection is a global health issue that not only causes acute helminthiasis but long-term infection may lead to complicated symptoms as well as severe complications. The World Health Organization cooperated with the Ministry of Public Health in many countries, particularly where high prevalence, spending a lot of resources for limiting the infection. In Thailand, the incidence of parasitic helminth infections was continuously declined in the last few decades according to several campaigns for parasitic elimination. However, the rural community in the northeast of Thailand where the highest prevalence of the country still needs to be monitored. This present study aims to report the current prevalence of parasitic helminth infections in Nakhon Ratchasima and Chaiyaphum provinces where sharing a huge area of the northeastern region of Thailand but only a few studies have been published.

METHODS

The stool specimens were collected from 11,196 volunteers and processed by modified Kato-Katz thick smear, PBS-ethyl acetate concentration techniques, and PCR. The epidemiological data were collected, analyzed, and used for generating of parasitic hotspots.

RESULTS

The results indicated that O. viverrini remains the major parasite in this area with a total prevalence of 5.05% followed by Taenia spp., Hookworms, T. trichiura, and Echinostoma spp., respectively. Mueang district of Chaiyaphum province has the highest prevalence especially O. viverrini with a prevalence of 7.15% that higher than the latest national surveillance. Interestingly, the prevalence of O. viverrini was hugely reported (more than 10%) in five subdistricts. The geographic localization of O. viverrini infections revealed that a lot of water reservoirs such as the lakes or branches of the river in the two-most prevalent subdistricts. Our finding indicated that gender and age were insignificantly different.

CONCLUSION

This finding suggested that the parasitic helminth infection in the rural areas of northeast of Thailand remains high and the housing location is a major contributing factor for the parasitic infection.

An Epidemiological Survey of Intestinal Parasitic Infection and the Socioeconomic Status of the Ethnic Minority People of Moken and Orang Laut

Ethnic minority groups are often subjected to exclusion, social and healthcare marginalization, and poverty. There appears to be important linkages between ethnic minority groups, poor socioeconomic status, and a high prevalence of parasitic infection. Data regarding the prevalence and health effects of IPIs are necessary in the development and implementation of targeted prevention and control strategies to eradicate intestinal parasitic infection in the high-risk population. Thus, we investigated for the first time the intestinal parasitic infection status (IPIs), the socioeconomic status, and sanitary condition in the communities of Moken and Orang Laut, the ethnic minority peoples living on the coast of southwest Thailand. A total of 691 participants participated in the present study. The information concerning socioeconomic status and sanitary condition of the study population was obtained by personal interviews using a picture questionnaire. Stool samples were collected and examined for intestinal parasitic infection using direct wet smear and formalin-ethyl acetate concentration techniques. The results revealed that 62% of the study population were infected with one or more types of intestinal parasites. The highest prevalence of intestinal parasitic infections was found in the 11–20-year-old age range group. A statistically significant difference of IPIs among the three communities were observed (p < 0.0001). There was a statistical difference concerning 44 multiple infections of soil-transmitted helminths (STHs) (p < 0.001), whereas no statistically significant difference in multiple infections of protozoa was observed (p > 0.55). The results also displayed the significant difference in socioeconomic status and sanitary condition among the Moken living in Ranong and Phang Nga and the Orang Laut living in the Satun province (p < 0.001). Our study found no direct association between parasitic infection status and ethnic/geographic features; however, socioeconomic status is the key factor associated with prevalence of intestinal parasitic infection, with the observation that the higher prevalence of IPIs is due to a low socioeconomic status, consequently leading to poor hygiene and sanitation practices. The picture questionnaire played a major role in information gathering, especially from those of low or no education. Lastly, data pertaining to the species of the parasites and the mode of transmission assisted in the identification of group-specific vulnerabilities and shortcomings that can be utilized in education and corrected to reduce the prevalence of infection in the study areas.

Global prevalence of 4 neglected foodborne trematodes targeted for control by WHO: A scoping review to highlight the gaps

BACKGROUND

Foodborne trematodiases (FBTs) are a group of trematodes targeted for control as part of the World Health Organization (WHO) road map for neglected tropical diseases from 2021 to 2030. Disease mapping; surveillance; and capacity, awareness, and advocacy building are critical to reach the 2030 targets. This review aims to synthesise available data on FBT prevalence, risk factors, prevention, testing, and treatment.

METHODS

We searched the scientific literature and extracted prevalence data as well as qualitative data on the geographical and sociocultural risk factors associated with infection, preventive/protective factors, and methods and challenges of diagnostics and treatment. We also extracted WHO Global Health Observatory data representing the countries that reported FBTs during 2010 to 2019.

RESULTS

One hundred and fifteen studies reporting data on any of the 4 FBTs of focus (Fasciola spp., Paragonimus spp., Clonorchis sp., and Opisthorchis spp.) were included in the final selection. Opisthorchiasis was the most commonly reported and researched FBT, with recorded study prevalence ranging from 0.66% to 88.7% in Asia, and this was the highest FBT prevalence overall. The highest recorded study prevalence for clonorchiasis was 59.6%, reported in Asia. Fascioliasis was reported in all regions, with the highest prevalence of 24.77% reported in the Americas. The least data was available on paragonimiasis, with the highest reported study prevalence of 14.9% in Africa. WHO Global Health Observatory data indicated 93/224 (42%) countries reported at least 1 FBT and 26 countries are likely co-endemic to 2 or more FBTs. However, only 3 countries had conducted prevalence estimates for multiple FBTs in the published literature between 2010 to 2020. Despite differing epidemiology, there were overlapping risk factors for all FBTs in all geographical areas, including proximity to rural and agricultural environments; consumption of raw contaminated food; and limited water, hygiene, and sanitation. Mass drug administration and increased awareness and health education were commonly reported preventive factors for all FBTs. FBTs were primarily diagnosed using faecal parasitological testing. Triclabendazole was the most reported treatment for fascioliasis, while praziquantel was the primary treatment for paragonimiasis, clonorchiasis, and opisthorchiasis. Low sensitivity of diagnostic tests as well as reinfection due to continued high-risk food consumption habits were common factors.

CONCLUSION

This review presents an up-to-date synthesis on the quantitative and qualitative evidence available for the 4 FBTs. The data show a large gap between what is being estimated and what is being reported. Although progress has been made with control programmes in several endemic areas, sustained effort is needed to improve surveillance data on FBTs and identify endemic and high-risk areas for environmental exposures, through a One Health approach, to achieve the 2030 goals of FBT prevention.

Slight Changes in the Gut Microbiome in Early-stage Chronic Kidney Disease of Unknown Etiology

Gut dysbiosis and changes in short-chain fatty acids (SCFAs) occur in end-stage chronic kidney disease (CKD); however, the degree of these changes in the gut microbiome and serum SCFA profiles in the early stages of CKD,‍ ‍particularly in‍ ‍CKD‍ ‍of unknown etiology (CKDu), is unclear. We herein investigated the gut microbiome and SCFA profiles of early-stage CKD patients (CKD stages 1-3) in a community in Khon Kaen Province, Thailand. Seventy-two parasite-free participants were distributed among a healthy control group (HC, n=18) and three patient groups (an underlying disease group [UD, n=18], early-stage CKD with underlying disease [CKD-UD, n=18], and early-stage CKD of unknown etiology, [CKDu, n=18]). Fecal DNA was individually extracted and pooled for groups of six individuals (three pools in each group) to examine the composition of the gut microbiome using next-generation sequencing. A SCFA ana-lysis was performed on serum samples from each individual using gas chromatography-mass spectrometry. The results revealed that microbial abundance differed between the healthy group and all patient groups (UD, CKD-UD, and CKDu). [Eubacterium]_coprostanoligenes_group was more abundant in the CKDu group than in the HC and CKD-UD groups. Furthermore, serum concentrations of acetate, a major SCFA component, were significantly lower in all patient groups than in the HC group. The present results indicate that minor changes in the gut microbiome and a significant decrease in serum acetate concentrations occur in early-stage CKDu, which may be important for the development of prevention strategies for CKD patients.

Molecular Identification, Pathogenesis, and Life Cycle of Sarcocystis cruzi from Cattle (Bos taurus) in New Valley Governorate, Egypt

Sarcocystis cruzi was identified by molecular methods from an intermediate host, cattle (Bos taurus), in El-Kharga, New Valley Governorate, Egypt, and its life cycle and pathogenicity were studied in the final host, dogs (Canis familiaris). 600 slaughtered cattle aged 6-8 years (480/120 males/females) were included. In addition, three laboratory-bred, coccidian-free puppies aged 2-3 months were fed infected bovine muscles to locate the definitive host and analyze sporogony. 18S rRNA-specific gene primers were used for DNA amplification from esophageal muscles. These polymerase chain reaction (PCR) amplicons were subjected to restriction fragment length polymorphism (RFLP) and molecular sequence analysis. Infection was detected in 78.8% (473/600; 95% CI, 75.56-82.11%). Histopathological examination of esophageal muscles showed oval- to spherical-shaped cysts, 96.7 μm wide by 326.9 μm long; cysts in cardiac muscles were ovoid and smaller. Infected puppies began shedding sporocysts in feces 7 days post-inoculation and showed distorted organ architecture, severe cellular damage, and inflammatory lesions in liver, kidney, esophagus, and stomach. Three oocysts with different shapes and sizes were identified. Partial 18S rRNA gene sequences of isolated New Valley sarcocysts were identical to S. cruzi isolated from different areas, verifying their genetic relatedness. Our analysis suggests that S. cruzi is the most prevalent in slaughtered cattle in New Valley Governorate, Egypt.

Prevalence and Associated Risk Factors of Intestinal Parasitic Infections: A Population-Based Study in Phra Lap Sub-District, Mueang Khon Kaen District, Khon Kaen Province, Northeastern Thailand

Intestinal parasitic infections are still a crucial problem among communities in Northeast Thailand. Misuse of antiparasitic drugs and unhealthy food behaviors are known. This study aimed to explore the prevalence, behavioral health factors, and motivation for self-treatment of anti-parasitic drugs in this area. A community-based cross-sectional study was conducted in Phra Lap sub-district, Mu Khon Kaen district, Khon Kaen province, Northeast Thailand, in 2016. A total of 419 participants were recruited to complete a self-administered questionnaire and stool examination. Binary logistic regression was used to assess the association between the risk factor and parasitic infection. Forty-two participants (10%; 95%CI 7.5-13.3) were positive for at least one parasite species. In this community, the most detected intestinal parasite was Opisthorchis viverrini (5.3%), followed by Strongyloides stercoralis (3.1%). A total of 67.5% of the participants had the experience of anti-parasitic drug treatment within previous 1 year, and "Often eat raw food" was the most common reason for the use of anti-parasitic drugs. On multivariate analysis, parasitic infections were significantly associated with male gender (ORadj. 2.42; 95%CI 1.00-5.85), age ≥ 60 years (ORadj. 7.55; 95%CI 1.60-35.76), and often consuming raw food of at least one type (ORadj. 2.37; 95%CI 1.03-5.44). Given these findings, correction of the dietary habit of eating raw fish/meat, which is the most important measure, and limitation of the use of anthelmintic treatment for individuals with stools positive for ova as well as emphasis on sanitary toilets will be implemented for the prevention and control of parasitic infection in endemic communities.

Molecular detection and phylogeny of Ehrlichia canis and Anaplasma platys in naturally infected dogs in Central and Northeast Thailand

Background and Aim

Ehrlichia canis and Anaplasma platys are tick-borne, Gram-negative bacteria that cause canine monocytic ehrlichiosis and canine cyclic thrombocytopenia, respectively. These diseases are of great importance and are distributed globally. This study aimed to create new primers for the identification of E. canis and A. platys in naturally infected dogs using polymerase chain reaction (PCR), DNA sequencing, and phylogenetic analysis using the 16S rDNA and gltA genes.

Materials and Methods

In total, 120 blood samples were collected from dogs in three different locations (Saraburi, Buriram, and Nakhon Ratchasima provinces) in Central and Northeast Thailand. The molecular prevalence of E. canis and A. platys was assessed using PCR targeting the 16S rDNA and gltA genes. All positive PCR amplicons were sequenced, and phylogenetic trees were constructed based on the maximum likelihood method.

Results

Ehrlichia canis had an overall molecular prevalence of 15.8% based on the 16S rDNA gene, compared to 8.3% based on the gltA gene. In addition, the overall molecular prevalence of A. platys using the 16S rDNA gene was 10.8%, while the prevalence rate was 5.8% using the gltA gene. Coinfection was 0.8% in Saraburi province. The partial sequences of the 16S rDNA and gltA genes of E. canis and A. platys in dogs in Central and Northeast Thailand showed 96.75%-100% identity to reference sequences in GenBank. Phylogenetic analysis of the 16S rDNA and gltA genes revealed that E. canis and A. platys sequences were clearly grouped into their own clades.

Conclusion

This study demonstrated the molecular prevalence of E. canis and A. platys in Central and Northeast Thailand. The 16S rDNA and gltA genes were useful for the diagnosis of E. canis and A. platys. Based on the phylogenetic analysis, the partial sequences of the 16S rDNA and gltA genes in E. canis and A. platys were related to prior Thai strains and those from other countries.

Performance of Mini Parasep® SF stool concentrator kit, Kato-Katz, and formalin-ethyl acetate concentration methods for diagnosis of opisthorchiasis in Northeast Thailand

BACKGROUND

Control and elimination of the liver fluke (Opisthorchis viverrini) is a primary preventive strategy against cholangiocarcinoma in Southeast Asia. A sensitive parasitological diagnostic method is required to facilitate a surveillance and control program. In this study, we evaluated the performance of Mini Parasep® SF stool concentrator kit (stool kit) compared with Kato-Katz (KK) and the quantitative formalin-ethyl acetate concentration technique (FECT) for detection of O. viverrini and co-endemic parasitic infections.

METHODS

A cross-sectional survey for parasitic infection in residents aged > 15 years in a community in Kalasin province, Northeast Thailand, was conducted in 2018. Fecal samples were collected and screened by KK method, and a subset of samples was further examined by the stool kit and FECT methods. The results were analyzed for prevalence of parasitic infections in addition to the diagnostic performance of the methods for qualitative and quantitative detection of helminthiases.

RESULTS

The initial survey of parasitic infection determined by the KK method (n = 567) showed the prevalence of O. viverrini was 32.63%, followed by Taenia 2.65%, echinostomes 1.76%, hookworms 1.41%, Trichuris trichiura 0.53% and Strongyloides stercoralis 0.53%. Within a subset of samples tested with multiple diagnostics (n = 150), the detection rates of O. viverrini by the stool kit, FECT and KK methods were 27.3%, 30.7% and 28.7%, respectively. The diagnostic sensitivity for opisthorchiasis was similar for FECT (75.5%), KK(66.0%) and the stool kit (67.3%). For other parasitic infections, FECT and stool kit methods performed better than KK, particularly in detecting minute intestinal flukes (MIF), S. stercoralis and coinfections. When measuring the intensity of O. viverrini infection (fecal egg counts), the stool kit results showed a significant positive correlation with KK and FECT (P < 0.05).

CONCLUSIONS

As the stool kit is simple to use and shows a comparable performance to FECT, it may serve as an alternative method of fecal examination for screening of helminthiasis including opisthorchiasis.

Balantidium coli; Rare and Accidental Finding in the Urine of Pregnant Woman: Case Report

Background

Balantidium coli is a ciliated protozoan parasite, which causes intestinal and extraintestinal infections in humans. It is transmitted feco-orally by ingesting infective cysts with food and water. Urinary balantidiasis may occur through contamination (direct spread from the anal area), secondarily to rectovaginal fistula and following immune suppression. Data about cases of urinary balantidiasis are rare in the world. Currently, there are no documented reports of urinary balantidiasis in Ethiopia. As our understanding, there are only eleven documented reports of urinary balantidiasis globally. However, cases of urinary balantidiasis among pregnant women have not been documented yet. The aim of this report is to alarm health professionals for considering the occurrence of such rare cases and conduct diagnosis.

Case Presentation

A 24-year old pregnant woman was admitted due to severe preeclampsia and preterm delivery at Debre Tabor Comprehensive Specialized Hospital, gynecology ward. Her urine was presented to inpatient laboratory for routine urinalysis. We detected unusual and ciliated parasite from her urine sediment characterized by its active and rotary motility through its cilia and possessing macro- and micro-nuclei, several food vacuoles and ingested red blood cells inside the cytoplasm. Hematuria, many white blood cells and epithelial cells were also detected from the urine sediment, which suggests genito-urinary tract infection due to this parasite. This rare parasite finding was confirmed to be B. coli.

Conclusion

The route of transmission and extraintestinal existence from this woman’s urine was unclear. It might be due to feco-oral transmission and spread to the genitourinary tract through direct anal contact. Moreover, it might be associated with immune suppression as she is pregnant woman.

Knowledge, Attitudes, and Practices regarding Soil-Transmitted Helminthiasis among Village Health Volunteers in Nakhon Si Thammarat Province, Thailand: A Cross-Sectional Study

Soil-transmitted helminth infections are most prevalent in rural populations. Village health volunteers (VHVs) are the key individuals for Thai primary healthcare. Therefore, this study aimed to investigate the knowledge, attitudes, and practices regarding soil-transmitted helminthiasis in VHVs. A questionnaire survey was conducted among 552 VHVs randomly selected from four subdistricts in a southern province of Thailand. Sociodemographic variables and information regarding the knowledge, attitudes, and practices related to soil-transmitted helminthiasis were collected using a structured questionnaire. The results demonstrated that VHVs had poor knowledge (70.47%) and practices (66.49%); however, 69.57% had good attitudes. Most VHVs had inadequate knowledge and practices regarding soil-transmitted helminthiasis. VHVs who had been trained in parasitic infection control measures were 2.18 times more likely to have good knowledge. VHVs with a monthly family income of more than 307 USD were 1.58 times more likely to have a good attitude. VHVs with good knowledge were more likely to have good practices. In conclusion, the development of training programs and health promotion should be considered to enhance the knowledge, attitudes, and practices related to soil-transmitted helminthiasis in VHVs, who are the key individuals for providing health education to community members.

First report on molecular characteristics and risk factor analysis of Ehrlichia canis in dogs in Khon Kaen, Thailand

Background and Aim:

Ehrlichia canis is a well-known cause of both anemia and thrombocytopenia in dogs. There are insufficient epidemiological data on this blood parasite in Thailand and the association of infections with hematological abnormalities. This study aimed to analyze the molecular characteristics and to identify E. canis as well as the risk factors associated with E. canis infection in dogs in Khon Kaen, Thailand.

Materials and Methods:

Blood samples from 126 dogs that visited animal clinics were subjected to molecular detection using nested polymerase chain reaction for E. canis16S rRNA gene. The risk factors and hematological profiles associated with the infection were analyzed using the logistic regression test in program SPSS version 19.

Results:

Forty-one dogs were infected, indicating a 32.5% molecular infection rate of E. canis. The factors significantly associated with E. canis infection include animal housing status, low packed cell volume, low red blood cell count, and low platelets (p<0.05). Ten positive samples were amplified, sequenced, and phylogenetically analyzed. Sequence and phylogenetic analysis confirmed the current ten samples as E. canis compared with reference sequences in GenBank, using the BLAST program hosted by NCBI, which showed 99.74-100% similarity.

Conclusion:

This study provided the first data of infection rate of E. canis using nested PCR and molecular characteristics of E. canis in randomly selected domestic dogs in Khon Kaen, Thailand.

Development and Efficacy of Droplet Digital PCR for Detection of Strongyloides stercoralis in Stool

Human strongyloidiasis is one of the neglected tropical diseases caused by infection with soil-transmitted helminth Strongyloides stercoralis. Conventional stool examination, a method commonly used for diagnosis of S. stercoralis, has low sensitivity, especially in the case of light infections. Herein, we developed the droplet digital polymerase chain reaction (ddPCR) assay to detect S. stercoralis larvae in stool and compared its performance with real-time PCR and stool examination techniques (formalin ethyl-acetate concentration technique [FECT] and agar plate culture [APC]). The ddPCR results showed 98% sensitivity and 90% specificity, and real-time PCR showed 82% sensitivity and 76.7% specificity when compared with the microscopic methods. Moreover, ddPCR could detect a single S. stercoralis larva in feces, and cross-reactions with other parasites were not observed. In conclusion, a novel ddPCR method exhibited high sensitivity and specificity for detection of S. stercoralis in stool samples. This technique may help to improve diagnosis, particularly in cases with light infection. In addition, ddPCR technique might be useful for screening patients before starting immunosuppressive drug therapy, and follow-up after treatment of strongyloidiasis.

Opisthorchis viverrini and Strongyloides stercoralis mono- and co-infections: Bayesian geostatistical analysis in an endemic area, Thailand

Parasitic infections caused by Opisthorchis viverrini and Strongyloides stercoralis remain a major public health threat in the Greater Mekong Sub-region. An understanding of climate and other environmental influences on the geographical distribution and emergence of parasitic diseases is a crucial step to guide targeted control and prevention programs. A parasitological survey was conducted from 2008 to 2013 and included 12,554 individuals (age between 20 and 60 years) from 142 villages in five districts in Khon Kaen Province, Thailand. Geographical information systems, remote sensing technologies and a Bayesian geostatistical framework were used to develop models for O. viverrini and S. stercoralis mono- and co-infections in areas where both parasites are known to co-occur. The results indicate that male sex, increased age, altitude, precipitation, and land surface temperature have influenced the infection rate and geographical distribution of mono- and co-infections of O. viverrini and S. stercoralis in this area. Males were 6.69 times (95% CrI: 5.26-8.58) more likely to have O. viverrini - S. stercoralis co-infection. We observed that O. viverrini and S. stercoralis mono-infections display distinct spatial pattern, while co-infection is predicted in the center and southeast of the study area. The observed spatial clustering of O. viverrini and S. stercoralis provides valuable information for the spatial targeting of prevention interventions in this area.

Balantidiasis in humans: A systematic review and meta-analysis

Balantioides coli is a protozoan that infects different hosts species, including humans, with zoonotic transmission. The parasite, which lives in the large intestine and in other organs, can lead to serious infections that may culminate in death. Information about human balantidiasis is generally still very scanty. In view of the above, the purpose of this study was to analyze the epidemiological, clinical and laboratory characteristics of human balantidiasis based on a systematic review and meta-analysis. The scientific articles were retrieved from various databases and were subjected to descriptive analyses, chi-squared tests, and summarized on a forest plot and the heterogeneity index (I²). A total of 103 articles were eligible and included in this review. Out of these 103 articles, 75 were clinical case reports and 28 were epidemiological studies, indicating a frequency of 997 (3.98%) people potentially infected with B. coli. The publication dates of the analyzed articles ranged from 1910 to 2020, but the majority (68.9%) were published between 1998 and 2020. A considerable number of these articles were published in South America and Asia, mostly in Brazil and India, respectively. However, in Africa, Ethiopia, was observed the higher number of infected people (47.5%). A significant association (p < 0.05) was identified between proximity to pigs and positivity for B. coli, since more than 16% infected people were in proximity with pigs and/or their excreta. Infection by the protozoan was classified mainly as intestinal, and the predominant symptom was dysentery. Extraintestinal infections were found in 27 individuals, with colonization of the genitourinary tract frequently highlighted. Direct examination (17.2%), followed by an association of direct examination and sedimentation (45.7%), were the most commonly performed parasitological techniques, and the most frequently diagnosed form was trophozoites, corresponding to 22.5% of cases. The most common treatment for parasitized individuals (11.8%) was an association of tetracycline drugs with nitroimidazole derivatives. The articles retrieved, mainly epidemiological ones, used in meta-analysis showed high heterogeneity (I²> 50%, p < 0.05), impairing the retrieval and comparison of results. Some articles were found to provide incomplete information, making it difficult to retrieve and analyze variables. However, this review enabled us to compile and restate factors that appear to be associated with cases of human balantidiasis.

Current status of helminthiases in Thailand: A cross-sectional, nationwide survey, 2019

Helminthiases are common neglected tropical diseases in Thailand, thus regular surveillance is necessary for their control. During fiscal year 2019, the Thailand Ministry of Public Health carried out a cross-sectional nationwide survey in people of all age groups from the 12 Regional Health Offices in 76 provinces of Thailand. Multi-stage cluster random sampling design was employed to assess the prevalence of helminth infections and certain behavioural risk factors. A total of 16,187 stool samples and demographic data were obtained from the participants. Stool examination was done and parasite eggs/lavae were identified microscopically by experienced technicians. Positive stool samples for Opisthorchis viverrini, hookworms, or Ascaris lumbricoides were further quantified and expressed in eggs per gram feces (EPG). The results revealed an overall prevalence of helminthic infections of 9.79% with over 14 species identified. The highest prevalence was hookworms (4.47%) followed by O. viverrini (2.2%) with mean infection intensities of 222.7 EPG and 120.9, respectively. The majority of the infections were low intensity (97.4% for hookworms and 99.1% for O. viverrini). Similarly for A. lumbricoides, 93.9% of the positive cases were low infections. Two major helminthiases caused by hookworms and O. viverrini were highlighted in this report. While the liver fluke was highly endemic in Northeast Thailand, the hookworms were prevalent in the southmost region of the country. Association with demographic characteristics and risk behaviors of the two parasites were analyzed and presented in this study. Overall, this countrywide survey provides basic information of the current status of helminth infections in Thailand. Moreover, the data clearly indicates a dramatic reduction of O. viverrini prevalence likely due to extensive control activities under the national campaign against the liver fluke over the past five years.

Prevalence of Opisthorchis viverrini and Its Associated Risk Factors in the Phon Sawan District of Nakhon Phanom Province, Thailand

Background:

Opisthorchis viverrini is one of the endemic helminths in Thailand. Nonetheless, O. viverrini still exist and raise concerns regarding public health. This study aimed to evaluate the current prevalence of O. viverrini infections and underlying risk factors among rural communities in Northeast Thailand.

Methods:

A cross-sectional study was conducted between Sep and Dec 2019 in Phon Sawan district in Nakhon Phanom Province, Thailand. The participants were selected using a voluntary sampling method after the proportional allocation of the total sample size. Demographic data were collected using a standardized questionnaire. One stool sample was collected from each participant and the presence of O. viverrini and other intestinal parasite infections were determined using the modified Kato-Katz technique.

Results:

Overall, 250 participants aged 21 yr or older were enrolled. Overall, the prevalence of O. viverrini and Strongyloides stercoralis was 24% (95% confidence interval [CI]: 18.8–29.8) and 1.2% (95% CI: 0.2–3.5), respectively. Of the positive O. viverrini cases, the parasite rate significantly differed between gender, age group and in those who had a history of eating raw fish and taking the anti-helminthic drug (all P<0.05). Nevertheless, multivariate regression analysis among O. viverrini cases revealed that only being male (adjusted odds ratio [aOR] 1.9 [95% CI: 1.1 – 3.6], P = 0.033) and aged ≥61 yr (aOR 6.7 [95% CI: 1.4 – 32.5], P=0.018) were positively associated with a higher risk of O. viverrini infection.

Conclusion:

Opisthorchiasis and strongyloidiasis are still endemic in this area and there is a need for projects to eliminate these parasites.

The Coexistence of Blastocystis spp. in Humans, Animals and Environmental Sources from 2010-2021 in Asia

Blastocystis spp. are controversial unicellular protists that inhabit the gastrointestinal tract of humans and a wide range of animals worldwide. This review provides an overview of the prevalence and distribution of Blastocystis spp. and their subtypes throughout Asia. Research articles reporting on the presence of Blastocystis spp. in locations within Asia, between 1 January 2010, and 10 May 2021, were obtained from Scopus, PubMed, and Google Scholar. In 427 articles, the prevalence of Blastocystis spp. in 31 countries within the last decade was revealed. Isolates were found in humans, various mammals, birds, reptiles, insects, water sources, vegetables, and ambient air. Prevalence of Blastocystis spp. varied widely across host categories. Subtypes identified throughout Asia were STs 1-14, and ST18-22 (novel subtypes). ST1, ST2, ST3, ST4 were the most frequently isolated in humans; ST5 in pigs; ST10 and ST14 in goats, sheep, and cattle; and ST6 and ST7 in chickens. ST1 and ST3 were most common in water samples. ST1, ST2, ST3, ST4, ST5 and ST6 were shared by humans, animals, and water sources. There is a growing interest in the study of Blastocystis spp. and their subtypes in Asia. Due to the isolation of Blastocystis spp. from biotic and abiotic sources in Asia, the application of the One Health (OH) approach to the study of Blastocystis spp. is proposed for improved perception of this organism.

One Health Approach of Melioidosis and Gastrointestinal Parasitic Infections from Macaca fascicularis to Human at Kosumpee Forest Park, Maha Sarakham, Thailand

Background and Objectives

Gastrointestinal parasitic and melioidosis infections are major causes of morbidity and mortality from infectious disease in rural areas, especially in northeastern Thailand. Both diseases are zoonotic giving rise to health problems in both long-tailed macaques and in humans. In Thailand, macaques have adapted to live and share space with humans and can spread some zoonoses to humans. Therefore, this research aimed to measure the prevalence of gastrointestinal parasitic infections and melioidosis in long-tailed macaques at Kosumpee Forest Park and measure associated risk factors of their diseases among people in this area.

Methods

This study was conducted at Kosumpee Forest Park, Maha Sarakham, Thailand. Twenty-eight blood samples and 135 fecal samples were collected from free-ranging long-tailed macaques. Blood samples were tested by indirect hemagglutination test and fecal samples were analyzed by formalin–ethyl acetate concentration technique. A cross-sectional study was conducted among 350 respondents who were involved with the Forest Park using a multi-stage stratified random sampling method and performed to measure knowledge, attitude, and practice toward the zoonoses among the respondents.

Results

It was found that seroprevalence of melioidosis was 57.1% from macaque samples. The prevalence of gastrointestinal parasites infection was 35.11% from fecces samples, including Strongyloides spp. (15.27%), Trichuris spp. (22.9%), hookworm (4.58%) and Ascarid spp. (1.53%). KAP study indicated that the level of knowledge related to melioidosis and gastrointestinal parasites of people in the area was very low and moderate, respectively. The attitude of respondents who were aware of the diseases was at a moderate level for melioidosis and a high level for parasitic infection.

Conclusion

The study therefore emphasizes the importance of one health approach for diagnosis, surveillance and management of zoonotic diseases to promote the development of hygiene measures and to educate people in the community around Kosumpee Forest Park.

Analysis of D-A locus of tRNA-linked short tandem repeats reveals transmission of Entamoeba histolytica and E. dispar among students in the Thai-Myanmar border region of northwest Thailand

Intestinal parasitic infections, including those caused by Entamoeba species, are a persistent problem in rural areas of Thailand. The aims of this study were to identify pathogenic Entamoeba species and to analyze their genotypic diversity. Stool samples were collected from 1,233 students of three schools located in the Thai-Myanmar border region of Tak Province, Thailand. The prevalence of Entamoeba infection was measured by polymerase chain reaction (PCR) using species-specific primers. Thirty-one (2.5%) positive cases were detected for E. histolytica, 55 (4.5%) for E. dispar, and 271 (22.0%) for E. coli. Positive samples for E. histolytica and E. dispar were exclusively obtained from a few school classes, whereas E. coli was detected in all grades. No infections caused by E. moshkovskii, E. nuttalli, E. chattoni, and E. polecki were detected in the students studied. The D-A locus of tRNA-linked short tandem repeats was analyzed in samples of E. histolytica (n = 13) and E. dispar (n = 47) to investigate their diversity and potential modes of transmission. Five genotypes of E. histolytica and 13 genotypes of E. dispar were identified. Sequences of the D-A were divergent, but several unique genotypes were significantly prevalent in limited classes, indicating that intra-classroom transmission has occurred. As it was unlikely that infection would have been limited within school classes if the mode of transmission of E. histolytica and E. dispar had been through the intake of contaminated drinking water or food, these results suggest a direct or indirect person-to-person transmission mode within school classes. Positive rates for three Entamoeba species were 2-fold higher in students who had siblings in the schools than in those without siblings, suggesting that transmission occurred even at home due to heavy contacts among siblings.

Transmissions in endemic areas of the pathogen Entamoeba histolytica and other non-pathogenic Entamoeba species such as E. dispar and E. coli are caused by ingestion of drinking water and foods contaminated with cysts of the parasites. Cases of Entamoeba infections among school-aged children have been reported in several countries. However, it has not been demonstrated that transmission of protozoa of the Entamoeba genus occurs within school facilities. In addition, genetic information on E. histolytica and other morphologically indistinguishable species, including E. dispar and E. moshkovskii, in Thailand remains scarce. In the present study, we demonstrated that E. histolytica and/or E. dispar are prevalent among school-aged children, but limited to few classes in three rural schools in the Thai-Myanmar border region of northwest Thailand. Although various genotypes of these Entamoeba species were identified, identical genotypes were significantly more prevalent in certain school classes and also among siblings, suggesting that transmission occurred within the classrooms and at home. The possibility of person-to-person transmission among these students via direct or indirect contact during daily activities in classrooms and home is proposed.

Prevalence of soil-transmitted helminth infections and associated risk factors among elderly individuals living in rural areas of southern Thailand

Background

Soil-transmitted helminth (STH) infection is a neglected tropical disease affecting approximately 1.5 billion people worldwide. In past decades, most studies focused on STH infection in preschool-aged and school-aged children in different regions of Thailand. However, little is known about the prevalence and intensity of STH infection in the elderly population. Therefore, the aim of this study was to determine the current prevalence and intensity of STH infections and to identify associated risk factors among the elderly population.

Methods

A cross-sectional study was conducted from July to November 2019 to assess the prevalence of STH infections and associated risk factors among elderly populations living in five subdistricts of Thasala District, Nakhon Si Thammarat Province, Thailand. A total of 439 elderly individuals were selected using a random sampling technique. Each fresh stool sample was examined using the formalin ethyl acetate concentration technique (FECT), Kato-Katz thick smears and agar plate culture (APC). A structured questionnaire was used to obtain relevant information regarding associated risk factors for STH infection.

Results

The overall prevalence of STH infection was 15.7%. Hookworms (10.9%, 48/439) were the most prevalent STH species, followed by Strongyloides stercoralis (3.4%, 15/439) and Trichuris trichiura (2.1%, 9/439). Most elderly individuals infected with hookworms or T. trichiura had light-intensity infections. A higher prevalence of STH infection was observed among individuals aged older than 80 years (23.4%) than among those aged between 70 and 79 years (15.2%) and 60–69 years (14.5%). Males were 1.85-times more likely to present with STH infections than females. Not washing vegetables before eating increased the risk of STH infection by 3.19 times, while defecation in an open field increased the risk of STH infection by 2.65 times.

Conclusions

The findings suggested that STH infection is prevalent, and that hookworms are the most common STH species among elderly populations in southern Thailand. Personal hygiene and deworming programs should be implemented among the elderly population to reduce the risk and prevent the spread of STH infections.

Foodborne zoonotic parasites of the family Opisthorchiidae

Several foodborne zoonotic trematodes of the family Opisthorchiidae have been reported to infect people, specifically two genera, Clonorchis and Opisthorchis. Three species Clonorchis sinensis, Opisthorchis felineus and Opisthorchis viverrini are the most extensivley studied of the Opisthorchiidae. At least 680 million people worldwide are at risk of infection of these liver flukes through the consumption of raw or partially cooked freshwater cyprinid fish. An estimated 45 million people in Europe and Asia are currently infected with these liver flukes. Of these, the 35 million are infected with C. sinensis mainly in China, 10 million with O. viverrini in Southeast Asia, and 1.2 million with O. felineus in Eastern Europe and Russia. These liver flukes have been proven to be causative agents of bile duct cancer or cholangiocarcinoma (CCA). A multidisciplinary program should be implemented involving comprehensive research on molecular genetics, diagnosis, treatment, prevention, as well as educational and control programs should progressively be introduced and applied in endemic regions of O. viverrini, O. felineus and C. sinensis throughout their ranges, hence, opisthorchiasis and clonorchiasis free communities can be realised globally.

Eosinophilia and parasitic infestations in patients with chronic obstructive pulmonary disease

Eosinophilia may guide response to inhaled corticosteroid treatment in patients with chronic obstructive pulmonary disease (COPD). This study aimed to determine prevalence of eosinophilia and parasitic infestations in these patients. We conducted a prospective cohort study between February 2019 and January 2020 and screened 107 stable COPD patients. A total of 77 subjects (84.4% men) were included. Age was 73.8 ± 8.9 years. Forced expiratory volume in 1 s was 66.5 ± 25.5%. Smoking history was 25.9 ± 18 pack-years. Comorbidities included cardiovascular disease (57.1%). Respiratory symptoms were assessed by modified Medical Research Council dyspnea score (1.6 ± 0.8), chronic obstructive pulmonary disease Assessment Test score (9.3 ± 4.9), and 6-min walking distance (317.2 ± 135.2 m). Patients with blood eosinophil count at least 100 cells/μL were 79.2% and at least 300 cells/μL were 33.8%. Intestinal parasites were not found. Significant positive correlations were found between high blood eosinophilia and some post-bronchodilator lung function parameters. In conclusion, eosinophilic COPD was not uncommon. No intestinal parasite was found in this population. This study suggests that stool parasite exam might be omitted for routine practice.

Clinicaltrials.in.th Number: TCTR20191129002.

Epidemiology of Taenia saginata taeniosis/cysticercosis: a systematic review of the distribution in East, Southeast and South Asia

BACKGROUND

Taenia saginata is an important zoonotic parasite, causing taeniosis in humans and cysticercosis in bovines, the latter being a significant concern for the global beef industry. Many countries in East, Southeast and South Asia are experiencing rapid economic growth, and an increasing number of people in these countries are dependent on the livestock industry. Currently, however, an overview of the prevalence of T. saginata in this region is lacking. In this review, we analysed the available literature on T. saginata taeniosis and bovine cysticercosis for East, Southeast and South Asia.

METHODS

A systematic review was conducted, based on both published and grey literature. Articles published between 1990 and 2017 were mined for information on the occurrence, prevalence, and geographical distribution of T. saginata taeniosis and bovine cysticercosis in East, Southeast and South Asia.

RESULTS

The presence of T. saginata was described in 15 of 27 countries of the region, including Afghanistan, Cambodia, China, India, Indonesia, Japan, Lao PDR, Malaysia, Mongolia, Nepal, Pakistan, Philippines, South Korea, Thailand and Vietnam. The only country that reported an absence of T. saginata is Japan, although sporadic reports of imported cases and unconfirmed reports of autochthonous infections were identified. Nationwide surveys of taeniosis with systematic sample collection and high sample numbers were available for Cambodia, China, Lao PDR, and South Korea, although speciation of Taenia was not always performed. Regional prevalence of taeniosis and bovine cysticercosis in endemic regions ranged between 0.02-42.6%, and 0.76-46.7%, respectively. However, data for bovine cysticercosis were only available for five countries (Japan, Lao PDR, Mongolia, Pakistan and Vietnam).

CONCLUSIONS

The data indicate a widespread occurrence of T. saginata throughout East, Southeast and South Asia. Identification of Taenia spp. in human infections was frequently not performed, leading to gaps in knowledge about the distribution of human tapeworm infections, mainly in regions where different human Taenia species co-occur. A high prevalence of T. saginata taeniosis and bovine cysticercosis may reflect insufficiencies in sanitation, limited health education standards, and insufficient food safety measures. Therefore, there is a need to improve local surveillance, notification, and overall control systems.

Helminth infections and immunosenescence: The friend of my enemy

Age-associated alterations of the immune system, which known as "immunosenescence", is characterized by a decline in innate and adaptive immunity, which leading to increased susceptibility to age-associated diseases, such as infectious diseases, rheumatic disease and malignancies. On the other hand, helminth infections are among the most prevalent infections in older individuals, especially in the nursing homes. Most of helminth infections have minor clinical symptoms and usually causing chronic infections without treatment. Nevertheless, chronic helminthiasis alters immune responses somewhat similar to the immunosenescence. Some similarities also exist between helminth infections and immunosenescence: 1) both of them led to declining the immune responses; 2) undernutrition is a consequence of immunosenescence and helminthiasis; 3) vaccine efficacy declines in aging and individuals with helminth infections; 4) increase incidence and prevalence of infectious diseases in the elder individuals and patients with helminth infections; and 5) both of them promote tumorigenesis. Hence, it is probable that helminth infections in the elderly population can intensify the immunosenescence outcomes due to the synergistic immunoregulatory effects of each of them. It would be suggested that, diagnosis, treatment and prevention of helminth infections should be more considered in older individuals. Also, it would be suggested that helminths or their antigens can be used for investigation of immunosenescence because both of them possess some similarities in immune alterations. Taken together, this review offers new insights into the immunology of aging and helminth infections.

Prevalence of Intestinal Parasites among Rural Inhabitants of Fouman, Guilan Province, Northern Iran with Emphasis on Strongyloides stercoralis

BACKGROUND

Intestinal parasitic infections (IPIs) are among the most important etiologies of gastrointestinal disorders in developing countries. The present study was performed to determine the prevalence of IPIs in rural inhabitants of Fouman, northern Iran.

METHODS

Overall, 31 villages were randomly selected during 2015-2016. Stool samples were collected from 1500 inhabitants aged 2-87. The samples were examined by direct wet smear, formalin ethyl-acetate concentration and agar plate culture. Trichrome staining and modified acid-fast staining were used as confirmatory tests for intestinal amoeba and flagellates and cryptosporidium spp., respectively. Data were analyzed with Chi-Square and Fisher exact tests using SPSS.

RESULTS

8.06% of participants were positive for at least one intestinal parasite. The prevalence of mixed parasitic infections was 0.87%. The most prevalent IPIs were caused by Trichostrongylus spp. (3.13%), followed by Strongyloides stercoralis (1.5%), Giardia lamblia (1.3%), and Entamoeba coli (1.0%), Blastocystis hominis (0.86%), E. histolytica/dispar (0.53%), Endolimax nana (0.26%), Iodamoeba butschlii (0.13%), Trichuris trichiura (0.07%), Enterobius vermicularis (0.07%), Hook worm (0.07%) and E. hartmani (0.07%). Statistically, the prevalence of IPIs showed significant differences regarding the age groups, education status, occupation (P<0.001), and the habit of eating raw vegetables (P<0.007), whereas, the differences were insignificant with regard to sex (P=0.924) and water supply (P=0.088).

CONCLUSION

The prevalence of IPIs, especially soil-transmitted helminthes (STHs) has sharply decreased in northern Iran. Excluding Trichostrongylus spp. and S. stercoralis, other intestinal parasites only produce a marginal and unnoticeable health problem in this area, today.

The extent, nature, and pathogenic consequences of helminth polyparasitism in humans: A meta-analysis

Background

Individual helminth infections are ubiquitous in the tropics; geographical overlaps in endemicity and epidemiological reports suggest areas endemic for multiple helminthiases are also burdened with high prevalences of intestinal protozoan infections, malaria, tuberculosis (TB), and human immunodeficiency virus (HIV). Despite this, pathogens tend to be studied in isolation, and there remains a need for a better understanding of the community ecology and health consequences of helminth polyparasitism to inform the design of effective parasite control programs.

Methodology

We performed meta-analyses to (i) evaluate the commonality of polyparasitism for helminth-helminth, helminth-intestinal protozoa, helminth-malaria, helminth-TB, and helminth-HIV co-infections, (ii) assess the potential for interspecies interactions among helminth-helminth and helminth-intestinal protozoan infections, and (iii) determine the presence and magnitude of association between specific parasite pairs. Additionally, we conducted a review of reported health consequences of multiply-infected individuals compared to singly- or not multiply-infected individuals.

Principal findings

We found that helminth-helminth and helminth-intestinal protozoan multiple infections were significantly more common than single infections, while individuals with malaria, TB, and HIV were more likely to be singly-infected with these infections than co-infected with at least one helminth. Most observed species density distributions significantly differed from the expected distributions, suggesting the potential presence of interspecies interactions. All significant associations between parasite pairs were positive in direction, irrespective of the combination of pathogens. Polyparasitized individuals largely exhibited lower hemoglobin levels and higher anemia prevalence, while the differences in growth-related variables were mostly statistically insignificant.

Conclusions

Our findings confirm that helminth polyparasitism and co-infection with major diseases is common in the tropics. A multitude of factors acting at various hierarchical levels, such as interspecies interactions at the within-host infra-parasite community level and environmental variables at the higher host community level, could explain the observed positive associations between pathogens; there remains a need to develop new frameworks which can consider these multilevel factors to better understand the processes structuring parasite communities to accomplish their control.

Helminth infections are a highly prevalent global health problem. These parasitic worm infections occur in areas also burdened with intestinal protozoan infections, malaria, tuberculosis, and human immunodeficiency virus. While these pathogens tend to be studied in isolation, there remains a need to better understand the nature, extent, and health consequences of helminth polyparasitism and co-infection with major diseases. Here, we reviewed the literature and performed meta-analyses to evaluate the commonality of helminth polyparasitism and co-infection, the potential for interspecies interactions between parasites, the association between parasite pairs, and the health consequences among multiply-infected individuals. We confirmed that polyparasitism and co-infection with major diseases are common in the global South and found that multiply-infected individuals experienced worse health consequences when compared to singly or not-multiply infected individuals. Our analysis suggested the potential presence of interspecies interactions and we identified the existence of positive associations between parasite pairs. These findings support the call for integrating deworming into malaria, TB, and HIV treatment protocols and suggest there remains a need to improve our understanding of the factors influencing co-transmission to achieve sustainable parasite control.

A Simple Genotyping Method for Rapid Differentiation of Blastocystis Subtypes and Subtype Distribution of Blastocystis spp. in Thailand

Blastocystis spp. is one of the most common protozoa of humans and animals worldwide. The genetic diversity of Blastocystis spp. might be associated with a wide range of symptoms. However, the prevalence of each subtype is different in each country. Until now, there is no standard method for subtyping of Blastocystis spp. We developed a sequential restriction fragment length polymorphism (RFLP) analysis for the rapid differentiation of human Blastocystis subtypes. A large-scale study was also conducted to determine the subtype distribution of Blastocystis spp. in Thailand. Stool samples were collected from 1025 school-age students in four regions of Thailand. Blastocystis infections were identified by direct smear, formalin ethyl-acetate concentration technique (FECT), Boeck and Drbohlav’s Locke-Egg-Serum (LES) medium culture, and polymerase chain reaction (PCR) of small-subunit ribosomal DNA (SSU rDNA). Subtypes of Blastocystis spp. were determined by RFLP. Phylogenetic tree of partial SSU rDNA sequences of Blastocystis spp. was constructed using the Maximum Likelihood (ML) method. Out of 1025 students, 416 (40.6%) were positive for Blastocystis spp. Using two steps of RFLP reactions, we could determine subtype one–three among these students. Subtype 3 was the most common subtype (58.72%) in Thai students, followed by subtype 1 (31.2%), and subtype 2 (10.1%). Blastocystis subtype 3 was the most prevalent in all regions of Thailand. The subtype distribution of Blastocystis spp. in Thailand was different from other countries.

Long-Tailed Macaques (Macaca fascicularis) in Urban Landscapes: Gastrointestinal Parasitism and Barriers for Healthy Coexistence in Northeast Thailand

Gastrointestinal parasites have diverse life cycles that can involve people, animals, and the environment (e.g., water and soil), demonstrating the utility of One Health frameworks in characterizing infection risk. Kosumpee Forest Park (Thailand) is home to a dense population of long-tailed macaques (Macaca fascicularis) that frequently interact with tourists and local residents. Our study investigated the presence of zoonotic parasites, and barriers to healthy coexistence by conducting stool analysis on macaques (N = 102) and people (N = 115), and by examining risk factors for infection with a household questionnaire (N = 95). Overall, 44% of macaques and 12% of people were infected with one or more gastrointestinal helminths, including Strongyloides spp., Ascaris spp., and Trichuris sp. An adults-only generalized linear mixed model identified three factors significantly associated with human infection: household size, occupational exposure, and contact with macaque feces at home. Participants identified both advantages and disadvantages to living in close contact with macaques, suggesting that interventions to improve human and animal health in Kosumpee Forest Park would be welcome.

Prevalence and Associated Factors of Intestinal Parasitic Infections among Food Handlers at Prison, East and West Gojjam, Ethiopia

INTRODUCTION

One of the top ten major public health problems in developing countries including Ethiopia is the intestinal parasitic infection. Most of the time, intestinal parasitic infections do not show clinical signs and symptoms and also have a number of potential carriers, such as food handlers, which makes it too difficult to eradicate and control.

OBJECTIVE

The aim of this study is to assess the prevalence and associated factors of intestinal parasitic infection among food handlers at prison, East and West Gojjam, Ethiopia, 2017.

METHODS

An institution-based cross-sectional study design was conducted at East and West Gojjam prison. A total of 416 study participants, with a response rate of 82.7%, were included in the study for both stool exam and questioner. Data were collected using a structured questionnaire, and the sample was collected and examined based on the standard parasitological procedure. Epi data Version 3.1 was used to enter data, and SPSS version 20 was used to analyze the data.

RESULTS

The overall prevalence of intestinal parasitic infections in the present study was 61.9%. The most prevalent parasite was A. lumbricoides (157 (45.6%)). Protozoan infection was higher than helminth infection. Multiple intestinal infections were identified; among study participants, 34.6% had double infection. The most significant associated factors of intestinal parasitic infections were fingernail status, residence, information about food contamination related to intestinal parasitic infection, income, and handwashing before having contact with food and after toilet with water only.

CONCLUSIONS

A high proportion of intestinal parasitic infection was detected among food handlers working at East and West Gojjam prison. Training must be given to the food handlers on personal hygienic conditions (finger trimming, handwashing after toilet and before having contact with food with water and soap, etc.).

Parasitic infections in relation to practices and knowledge in a rural village in Northern Thailand with emphasis on fish-borne trematode infection

The present study integrates several aspects of a parasitological survey in a rural community village combining community knowledge of parasites, their potential transmission routes and health risk factors. A rural community located in Northern Thailand was surveyed for intestinal parasites, and an overall prevalence of 45.2% for helminths and 4.8% for protozoan infections was identified. Socio-demographic characteristics, customs and perceptions were compiled using individual questionnaires and interviews for participants surveyed for parasitic screening. The results allowed us to determine the knowledge and perception of local people concerning helminthic infection and transmission. Despite the fact that the participants in this community were aware of parasitic transmission routes, their widespread custom of eating raw fish and meat render the reduction of helminthiasis difficult. A detailed study on the infection of fish-borne parasitic trematodes, the most prevalent helminth, allowed us to determine that the distance from a given household to the river is a determinant of infection intensity. Health education activities organised in the local community resulted in a change in perception of risks associated with parasite transmission.

Impact of the health education and preventive equipment package (HEPEP) on prevention of Strongyloides stercoralis infection among rural communities in Northeast Thailand: a cluster randomized controlled trial

Background

Strongyloidiasis is prevalent in northeast Thailand. This study aimed to evaluate the impact of the Health Education and Preventive Equipment Package (HEPEP), a package we developed to improve awareness and aid in the prevention of Strongyloides stercoralis infection among rural communities in northeast Thailand.

Methods

This was an intervention trial conducted in 12 villages (six interventions and six controls) in rural areas of northeast Thailand from March 2016 to September 2017. Single stool sample was collected from each participant and examined using agar plate culture (APC) technique. Each participant was interviewed using a pre-tested questionnaire, treated with single dose of ivermectin (200 μg/Kg), and allocated to either the intervention or control group. Members of the intervention group were given “Practices to Prevent Strongyloidiasis” poster and vinyl boards containing information aimed at raising awareness of S. stercoralis and strongyloidiasis. In addition, they were given a poster lecture regarding the lifecycle of S. stercoralis before being treated with ivermectin. Aside from that, they were also given a protective equipment package. Monthly refresher courses were provided by village health volunteers (VHVs) regarding the health information they had received and proper equipment usage. The control group, on the other hand, was only provided with a five-minute lecture regarding strongyloidiasis. Assessment of new infection was conducted 3 months later in 327 and 318 participants in the intervention group and control group, respectively.

Results

The HEPEP had 41% greater efficacy in preventing S. stercoralis infection in the intervention group than the measures taken in the control group (adjusted Odds Ratio (aOR) = 0.59; 95%CI: 0.41 to 0.85, P-value = 0.005). The intervention group also scored significantly higher on all aspects of a test of S. stercoralis knowledge compared with the control group (mean difference (mean dif.) = 2.89, P-value = < 0.05).

Conclusions

The HEPEP was the first model that has been found to be effective in controlling of S. stercoralis in rural communities in the northeast Thailand. The results should encourage policy makers and public health personnel to improve control programs, as well as health promotion, with regard to parasites.

Trial registration

Thai Clinical Trials Registry (TCTR), Medical Research Foundation of Thailand, Medical Research Network of the Consortium of Thai Medical Schools: MedResNet (Thailand) (identification number: TCTR20180404002) Registered 4 April 2018 (retrospectively registered).

Electronic supplementary material

The online version of this article (10.1186/s12889-018-6081-6) contains supplementary material, which is available to authorized users.

Prevalence of intestinal parasitic infections and associated risk factors for hookworm infections among primary schoolchildren in rural areas of Nakhon Si Thammarat, southern Thailand

Background

Soil-transmitted helminth (STH) infections are among the most common type of infections worldwide and are widely distributed in tropical areas. In rural areas of southern Thailand where most land is used for agriculture, children are at risk of acquiring parasites, especially STHs. Assessing the current situation regarding parasitic infection in these areas is a prerequisite for developing appropriate control measures. This study is aimed at determining the prevalence of intestinal parasitic infections, the intensity of STH infections and the associated risk factors among primary schoolchildren in Nopphitam District, Nakhon Si Thammarat Province, Thailand.

Methods

A cross-sectional study involving 299 schoolchildren between 7 and 12 years of age was conducted between January and March 2016. A questionnaire administered by direct interviews was used to collect sociodemographic information and data on associated risk factors. Stool samples were processed using direct wet smears, formalin-ethyl acetate sedimentation concentration, and the modified Kato-Katz technique.

Results

The overall prevalence of intestinal parasites among the 299 children was 16% (48 of 299), with 32 children infected with hookworms (10.7%), 10 with Blastocystis hominis (3.3%), seven with Giardia intestinalis (1.6%), one with Enterobius vermicularis (0.3%), and one with Trichuris trichiura (0.3%). The hookworm infection intensity, measured by the median eggs per gram (EPG) of stool, was 1200 EPG (Interquartile range (IQR): 360–3200). Most children had light-intensity hookworm infections, but two had heavy-intensity infections. When participants included in the sample were classified by age, children 10–12 years old demonstrated higher intestinal parasite prevalence than those aged 7–9 years (adjusted odds ratio (AOR) = 2.3, 95% CI: 1.1–4.9, P = 0.030). Inadequate handwashing before meals was statistically associated with hookworm infections (AOR = 2.3; 95% CI: 1.1–4.8, P = 0.037).

Conclusions

This study highlights that hookworms are the most prevalent STH infection in the study area. Older age group (10–12 years) and inadequate handwashing before meals were statistically associated with hookworm infections. Accordingly, appropriate strategies and education on personal and environmental hygiene should be implemented. Moreover, the cost-effectiveness of mass drug administration in this area should be further investigated.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-6023-3) contains supplementary material, which is available to authorized users.

High diversity of Blastocystis subtypes isolated from asymptomatic adults living in Chiang Rai, Thailand

Blastocystis is a common and broadly distributed microbial eukaryote inhabiting the gut of humans and other animals. The genetic diversity of Blastocystis is extremely high comprising no less than 17 subtypes in mammals and birds. Nonetheless, little is known about the prevalence and distribution of Blastocystis subtypes colonising humans in Thailand. Molecular surveys of Blastocystis remain extremely limited and usually focus on the central, urban part of the country. To address this knowledge gap, we collected stool samples from a population of Thai adults (n = 178) residing in Chiang Rai Province. The barcoding region of the small subunit ribosomal RNA was employed to screen for Blastocystis and identify the subtype. Forty-one stool samples (23%) were identified as Blastocystis positive. Six of the nine subtypes that colonise humans were detected with subtype (ST) three being the most common (68%), followed by ST1 (17%) and ST7 (7%). Comparison of subtype prevalence across Thailand using all publicly available sequences showed that subtype distribution differs among geographic regions in the country. ST1 was most commonly encountered in the central region of Thailand, while ST3 dominated in the more rural north and northeast regions. ST2 was absent in the northeast, while ST7 was not found in the center. Thus, this study shows that ST prevalence and distribution differs not only among countries, but also among geographic regions within a country. Potential explanations for these observations are discussed herewith.

Current high prevalences of Strongyloides stercoralis and Opisthorchis viverrini infections in rural communities in northeast Thailand and associated risk factors

Background

Two important helminths, Strongyloides stercoralis (an intestinal roundworm) and Opisthorchis viverrini (a liver fluke), are endemic in northeast Thailand. There have been national campaigns in place aimed at the control and eradication of soil-transmitted helminthiasis and opisthorchiasis in Thailand for several decades. However, these helminths still exist and raise concerns regarding public health. This study aimed to evaluate the current prevalence of S. stercoralis and O. viverrini infections in rural communities in northeast Thailand. The data from this study will be useful to improve strategies for future helminth prevention and control.

Methods

A cross-sectional study was conducted from December 2016 to June 2017 in Mueang Khon Kaen district in Khon Kaen, Thailand. The participants were selected using a simple random sampling method. Demographic data were collected using a questionnaire. Stool samples were collected and processed using agar plate culture to determine the presence of S. stercoralis infection and an in-house formalin-ethyl acetate concentration technique to determine the presence of O. viverrini and other intestinal parasite infections (IPIs).

Results

In total, 602 persons were enrolled. However, only 526 were analyzed for S. stercoralis and 387 for O. viverrini risk factors. The overall prevalence of S. stercoralis infection was 23.0% (95% confidence interval [95%CI]: 19.4 to 26.6). The prevalence of O. viverrini infection and IPIs other than S. stercoralis was 20.4% (95%CI: 16.5 to 24.8). The prevalence of O. viverrini infection was 19.4% (95%CI: 15.6 to 23.7). Male sex was significantly associated with S. stercoralis infection [Adjusted Odds Ratio (aOR) 4.0; 95%CI: 2.5 to 6.2; P-value < 0.001]. Males were significantly more likely to be infected with O. viverrini and other IPIs (aOR 4.1; 95%CI: 2.3 to 7.2, P-value < 0.001).

Conclusions

This study demonstrated that the updated prevalence of intestinal parasite infections is still high in rural communities in northeast Thailand, especially that of strongyloidiasis and opisthorchiasis.

Intestinal parasite infections in a rural community of Rio de Janeiro (Brazil): Prevalence and genetic diversity of Blastocystis subtypes

Background

Intestinal parasitic infections are considered a serious public health problem and widely distributed worldwide, mainly in urban and rural environments of tropical and subtropical countries. Globally, soil-transmitted helminths and protozoa are the most common intestinal parasites. Blastocystis sp. is a highly prevalent suspected pathogenic protozoan, and considered an unusual protist due to its significant genetic diversity and host plasticity.

Methodology/main findings

A total of 294 stool samples were collected from inhabitants of three rural valleys in Rio de Janeiro, Brazil. The stool samples were evaluated by parasitological methods, fecal culture, nested PCR and PCR/Sequencing. Overall prevalence by parasitological analyses was 64.3% (189 out of 294 cases). Blastocystis sp. (55.8%) was the most prevalent, followed by Endolimax nana (18.7%), Entamoeba histolytica complex (7.1%), hookworm infection (7.1%), Entomoeba coli (5.8%), Giardia intestinalis (4.1%), Iodamoeba butchilii (1.0%), Trichuris trichiura (1.0%), Pentatrichomonas hominis (0.7%), Enterobius vermicularis (0.7%), Ascaris lumbricoides (0.7%) and Strongyloides stercoralis (0.7%). Prevalence of IPIs was significantly different by gender. Phylogenetic analysis of Blastocystis sp. and BLAST search revealed five different subtypes: ST3 (34.0%), ST1 (27.0%), ST2 (27.0%), ST4 (3.5%), ST8 (7.0%) and a non-identified subtype.

Conclusions/significance

Our findings demonstrate that intestinal parasite infection rates in rural areas of the Sumidouro municipality of Rio de Janeiro, Brazil are still high and remain a challenge to public health. Moreover, our data reveals significant genetic heterogeneity of Blastocystis sp. subtypes and a possible novel subtype, whose confirmation will require additional data. Our study contributes to the understanding of potential routes of transmission, epidemiology, and genetic diversity of Blastocystis sp. in rural areas both at a regional and global scale.

Prevalence of Intestinal Parasites and Associated Risk Factors for Infection among Rural Communities of Chachoengsao Province, Thailand

Intestinal parasitic infections remain a major public health problem in many parts of Thailand, particularly in rural areas. This study aimed to determine the prevalence of intestinal parasitic infections and associated risk factors among the people living in Huai Sai sub-district, Bang Khla district, Chachoengsao Province, central Thailand. A cross-sectional survey was carried out from June 2017 to August 2017 which included a total of 224 participants. Stool samples were examined using a simple direct smear and formalin ethyl acetate concentration technique. Association between risk factors and intestinal parasitic infections was assessed using multivariate logistic regression analysis. The overall prevalence of intestinal parasitic infections was 16.1%. Soil-transmitted helminth infections (14.3%) were more common than protozoan infections (1.8%). The most common intestinal parasites were hookworms (6.7%) followed by Strongyloides stercoralis, (5.0%), Ascaris lumbricoides (1.3%) and Trichuris trichiura (1.3%). Entamoeba histolytica/dispar (1.0%), Giardia intestinalis (0.4%), and Blastocystis hominis (0.4%) were the protozoans identified. A high prevalence of infections was found in male participants of ≥40 years who raised dogs in the households and did not wear boots while working fields. Multivariate analysis showed a significant association of intestinal parasitic infections with gender with the adjusted odds ratio (OR) of 2.4 and 95% confidence interval (CI) of 1.1–5.2 (P=0.020). The results showed a high prevalence of soil-transmitted helminth infections among adults in rural communities which were particularly apparent regarding the skin-penetrating species of nematodes. A greater focus on intervention is required by improving sanitation and personal hygiene to prevent the spread of intestinal parasitic infections.

First molecular characterization of Sarcocystis spp. in cattle in Qena Governorate, Upper Egypt

Cattle are intermediate hosts for several Sarcocystis species with different definitive hosts. The present study, to our knowledge, is the first to determine the prevalence of Sarcocystis infection and morphologically and molecularly identify Sarcocystis species in cattle in Qena Governorate, Upper Egypt. The samples were collected from the heart and oesophagus muscles of 84 slaughtered cattle (76 males and 8 females) aged between 11 months and 3 years from slaughterhouses in different localities in Qena Governorate, Upper Egypt. The samples were macroscopically and histologically examined, and the molecular identification of the species was performed using 18S ribosomal subunit DNA through PCR and DNA sequencing. Infection was detected in 72 out of 84 animals (85.7%) and was more prevalent in males (76.2%) than in females (9.5). Using light microscopy, the microscopic sarcocysts were observed to be thin-walled. Sequencing and genotyping revealed one isolate that had 99 and 100% identity, respectively, to Sarcocystis cruzi, while another isolate had 95 and 99% identity to Sarcocystis hjorti. The present study is the first to identify Sarcocystis infection in cattle in Qena Governorate, Upper Egypt both morphologically and molecularly. Sarcocystis cruzi and S. hjorti species were isolated from cattle, which is of veterinary importance and indicates that morphologically similar Sarcocystis species are genetically distinct. Additionally, the results show that Sarcocystis species are not host-specific.

Taxonomy, Ecology and Population Genetics of Opisthorchis viverrini and Its Intermediate Hosts

There have been considerable advances in our understanding of the systematics and ecology of Opisthorchis viverrini; however, this new knowledge has not only clarified but also complicated the situation. We now know that what was once considered to be a single species is, in fact, a species complex, with the individual species being confined to specific wetland areas. There is also a strong genetic association between the members of the O. viverrini species complex and their Bithynia snail intermediate hosts. Although this does not negate data collected before the recognition of this situation, it does lead to the caveat that regional and temporal variations in data collected may be related to the species examined. The advances in ecology have generally been spatially limited and have led, in part, to contradictory results that may well be related to nonrecognition of the species studied. It may also be related to natural temporal and spatial variation related, for example, to habitat characteristics. To understand the variation present, it will be necessary to conduct long-term (several years at least) sampling projects after defining the genetic characteristics of O. viverrini sensu lato and its Bithynia snail intermediate hosts.

Intestinal Parasitic Infections and Environmental Water Contamination in a Rural Village of Northern Lao PDR

A field survey studying intestinal parasites in humans and microbial pathogen contamination at environment was performed in a Laotian rural village to identify potential risks for disease outbreaks. A parasitological investigation was conducted in Ban Lak Sip village, Luang Prabang, Lao PDR involving fecal samples from 305 inhabitants as well as water samples taken from 3 sites of the local stream. Water analysis indicated the presence of several enteric pathogens, i.e., Aeromonas spp., Vibrio spp., E. coli H7, E. coli O157: H7, verocytotoxin-producing E. coli (VTEC), Shigella spp., and enteric adenovirus. The level of microbial pathogens contamination was associated with human activity, with greater levels of contamination found at the downstream site compared to the site at the village and upstream, respectively. Regarding intestinal parasites, the prevalence of helminth and protozoan infections were 68.9% and 27.2%, respectively. Eight helminth taxa were identified in fecal samples, i.e., 2 tapeworm species (Taenia sp. and Hymenolepis diminuta), 1 trematode (Opisthorchis sp.), and 5 nematodes (Ascaris lumbricoides, Trichuris trichiura, Strongyloides stercoralis, trichostrongylids, and hookworms). Six species of intestinal protists were identified, i.e., Blastocystis hominis, Cyclospora spp., Endolimax nana, Entamoeba histolytica/E. dispar, Entamoeba coli, and Giardia lamblia. Questionnaires and interviews were also conducted to determine risk factors of infection. These analyses together with a prevailing infection level suggested that most of villagers were exposed to parasites in a similar degree due to limited socio-economic differences and sharing of similar practices. Limited access to effective public health facilities is also a significant contributing factor.

Soil-Transmitted Helminths in Tropical Australia and Asia

Soil-transmitted helminths (STH) infect 2 billion people worldwide including significant numbers in South-East Asia (SEA). In Australia, STH are of less concern; however, indigenous communities are endemic for STH, including Strongyloides stercoralis, as well as for serious clinical infections due to other helminths such as Toxocara spp. The zoonotic hookworm Ancylostoma ceylanicum is also present in Australia and SEA, and may contribute to human infections particularly among pet owners. High human immigration rates to Australia from SEA, which is highly endemic for STH Strongyloides and Toxocara, has resulted in a high prevalence of these helminthic infections in immigrant communities, particularly since such individuals are not screened for worm infections upon entry. In this review, we consider the current state of STH infections in Australia and SEA.

Prevalence of intestinal parasitic infection and associated risk factors among village health volunteers in rural communities of southern Thailand

Background

Intestinal parasitic infections remain prevalent and constitute a public health problem in certain rural areas of Thailand. Village health volunteers (VHVs), who are members of a Thai healthcare alliance, function as key providers of health prevention measures, disease control, and health education and share national health promotion campaigns with community members. This study is aimed at evaluating the prevalence, intensity, and risk factors for intestinal parasitic infection in VHVs in order to design community awareness and health education campaigns for the target population.

Methods

This cross-sectional study was conducted between January to April 2016 among village health volunteers (VHVs) from four sub-districts of Nopphitam District, Nakhon Si Thammarat Province, southern Thailand. Subjects for the study were selected using a simple random sampling method. Socio-demographic variables and risk factors were collected by a structured questionnaire. Stool specimens were collected and processed using direct wet mount and formol-ether concentration techniques to determine the presence of parasites and modified Kato-Katz thick smear to determine the intensity of infection.

Results

A total of 324 VHVs were enrolled. The overall prevalence of intestinal helminths was 9.3% (95% confidence interval [CI]: 6.3–13.0). The prevalence of hookworm, Strongyloides stercoralis, and Trichuris trichiura were 8.0% (95% CI: 5.3–11.5), 0.9% (95% CI: 0.2–2.7), and 0.3% (95% CI: 0–1.7), respectively. Mean intensity of hookworm infection was 1732 eggs per gram of stool. The prevalence was lower for protozoan infection than for helminth infection. Blastocystis hominis accounted for the highest percentage of intestinal protozoan infections 4.0% (95% CI: 2.2–6.8), followed by Giardia intestinalis 0.6% (95% CI: 0–2.2). No statistically significant difference was observed in the prevalence of intestinal parasitic infection among sub-districts (p > 0.05). Having dogs at home was associated with soil-transmitted helminth (STH) infection in study participants (Crude prevalence ratio [CPR]: 2.3; 95% CI: 1.0–5.2).

Conclusions

This study is the first to describe the prevalence of intestinal parasitic infection VHVs from southern Thailand. Hookworm infection is more prevalent than other types of STH infection. The development of community awareness campaigns and appropriate control measures should be considered to reduce the prevalence of hookworm infection, especially among VHVs who are the key persons providing health education to the community.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4486-2) contains supplementary material, which is available to authorized users.

Role of socio-cultural and economic factors in cyprinid fish distribution networks and consumption in Lawa Lake region, Northeast Thailand: Novel perspectives on Opisthorchis viverrini transmission dynamics

Opisthorchis viverrini (Ov) is a fish-borne parasite endemic in parts of Lao PDR, Cambodia, southern Vietnam and Northeast Thailand (Isaan) where an estimated 10 million people are infected. Human Ov infection, associated with hepatobiliary complications, including cholangiocarcinoma (CCA), occurs when infected fish are consumed raw or undercooked, a longstanding cultural tradition in the region. This mixed- methods descriptive study was carried out in Isaan villages around Lawa Lake, Khon Kaen Province, known for their Ov endemicity. Focus group discussions (FGDs) and in depth interviews (IDIs) were used to explore socio-cultural determinants underlying raw fish consumption practices, and global positioning system (GPS) devices to map local fish distribution networks. Qualitative data affirmed major socio-cultural and dietary lifestyle transitions occurring consequent on recent decades of modernization policies and practices, but also the persistence of Isaan traditional raw-fish eating practices and incorrect beliefs about infection risk avoidance. Fish traders/middlemen purchase most of the catch at the lakeshore and play the dominant role in district market fish distribution networks, at least for the larger and less likely infected, fish species. The lower economic value of the small potentially-infected cyprinid fish means local fishermen typically distribute them free, or sell cheaply, to family and friends, effectively concentrating infection risk in already highly Ov infected villages. Our study confirmed the persistence of traditional Isaan raw-fish meal practices, despite major ongoing socio-cultural lifestyle transitions and decades of Ov infection health education programs. We contend that diffuse socio-cultural drivers underpin this practice, including its role as a valued cultural identity marker. A "fish economics" factor was also evident in the concentration of more likely infected fish back into local villages due to their low economic value at district market level. The complexity of factors supporting "risky" fish-eating traditions in Isaan underscores the importance of integrated liver fluke infection control strategies to draw on transdisciplinary knowledge beyond biomedicine and also embrace participatory protocols for engaging communities in developing, implementing and evaluating interventions.

Epidemiological Investigation of Parasitic Infection of Schoolchildren from Six Elementary Schools in Sakon Nakhon Province, Thailand

We conducted an epidemiological study of intestinal parasitic infection in 572 schoolchildren aged 4 to 12 years old from six elementary schools in Sakon Nakhon Province, Thailand from June 2013 to August 2014. We collected fecal, blood, and urine samples to investigate parasitic infection and conducted a questionnaire survey. Soil samples were examined for egg contamination. Fecal examination, using the formalin-ether sedimentation method, revealed that 39% of schoolchildren were infected with eight genera and eight species of parasites; three nematodes, two trematodes, one cestode, and two protozoa. Prevalence rates across the six schools (schools A through F) were: A (13%), B (15%), C (53%), D (11%), E (20%), and F (43%). Schools C and F showed significantly higher prevalence rates than the other schools (p<0.05). In school C, Necator americanus was detected in 49% of schoolchildren tested, while in school F a high prevalence of Opisthorchis viverrini and Heterophyes heterophyes, at a rate of 23% and 21%, respectively, was detected. The questionnaire survey revealed that health, hygiene practices and awareness were poor in school C. However, school F showed high levels of cognizance and practices relating to the prevention of infection. The schoolchildren ate a staple diet of undercooked river fish and the results revealed a high rate of fish-borne parasites. Soil samples showed Toxocara sp. contamination in and around the campus. Toxocara antibodies were detected in over 6% of schoolchildren. The use of urine samples, as opposed to serum samples, was found to be effective for antibody testing.

Prevalence and Risk Factors of Human Intestinal Parasites in Roudehen, Tehran Province, Iran

BACKGROUND

Intestinal parasitic infections are among the most common infections and health problems worldwide. Due to the lack of epidemiologic information of such infections, the prevalence of, and the risk factors for, enteric parasites were investigated in residents of Roudehen, Tehran Province, Iran.

METHODS

In this cross-sectional study, 561 triple fecal samples were collected through a two-stage cluster-sampling protocol from Jun to Dec 2014. The samples were examined by formalin-ether concentration, culture, and with molecular methods.

RESULTS

The prevalence of enteric parasites was 32.7% (95% CI 27.3-38). Blastocystis sp. was the most common intestinal protozoan (28.4%; 95% CI 23.7-33.0). The formalin-ether concentration and culture methods detected Blastocystis sp., Entamoeba coli, Giardia intestinalis, Dientamoeba fragilis, Iodamoeba butschlii, Entamoeba complex cysts or trophozoite, Chilomastix mesnilii, and Enterobius vermicularis. Single-round PCR assay for Entamoeba complex were identified Entamoeba dispar and E. moshkovskii. E. histolytica was not observed in any specimen. Multivariate analysis showed a significant association of parasites with water source and close animal contact. There was no correlation between infections and gender, age, occupation, education, or travel history. Protozoan infections were more common than helminth infections.

CONCLUSION

This study revealed a high prevalence of enteric protozoan parasite infection among citizens of Rodehen. As most of the species detected are transmitted through a water-resistant cyst, public and individual education on personal hygiene should be considered to reduce transmission of intestinal parasites in the population.

Changing patterns of prevalence in Opisthorchis viverrini sensu lato infection in children and adolescents in northeast Thailand

Infection with the liver fluke Opisthorchis viverrini sensu lato (s.l.), a group 1 carcinogen, is the most important risk factor for developing cholangiocarcinoma (CCA) in Southeast Asia. Cholangiocarcinoma is a fatal disease with the world's highest incidence being found in northeast Thailand. Liver fluke infection occurs through eating raw or partially cooked cyprinid fish containing metacercariae and, therefore, the control of O. viverrini s.l. infection should lead to a reduction in CCA incidence. In this report, we review and analyze the age-prevalence profile data of O. viverrini to reveal temporal changes in patterns of prevalence pre- and post-control programs in Thailand. The profiles of O. viverrini prevalence have transformed from high prevalence in school children prior to 1983 to low prevalences after 1994. This pattern strongly suggests the influence of the health education program on the likelihood of school children becoming infected. In conjunction with current developments in health and socioeconomic conditions, we predict that the incidence of CCA will be reduced with time as the population cohorts that experienced the education programs reach the age at which CCA is most likely to develop, i.e. >50 years. The lessons learned in Thailand may be applicable to other areas endemic for human liver flukes.

Zoonotic intestinal protozoan of the wild boars, Sus scrofa, in Persian Gulf's coastal area (Bushehr province), Southwestern Iran

Aim:

Wild boars, Sus scrofa, are potential reservoirs of many zoonotic diseases, and there are a possibility of transmission of the zoonotic diseases from these animals to humans and also domestic animals. This study aimed to evaluate the protozoan contamination of wild boars in the Persian Gulf’s coastal area (Bushehr Province), southwestern Iran.

Materials and Methods:

A total of 25 crossbred boars were collected during a course of vertebrate pest control in Bushehr province, in 2013. Samples were collected from the gastrointestinal tracts of each boar in 5% formalin, Bouin’s solution, sodium acetate-acetic acid-formalin, and polyvinyl alcohol fixatives. Fixed stool smears examined by trichrome and Ziehl–Neelsen staining.

Results:

Each of the 25 wild boars was infected with at least one of the intestinal protozoans. The rate of contamination with intestinal protozoan was 64% for Balantidium coli, 76% for Iodamoeba sp., 52% for Entamoeba polecki, 44% for Blastocystis sp. and 8% for Chilomastix sp. No intestinal coccidian was detected in studied boars when the stool samples were evaluated by Ziehl–Neelsen staining method.

Conclusion:

Findings of this study demonstrated that wild boars in the Persian Gulf coastal area are contaminated by many protozoans, including zoonotic protozoan, which poses a potential risk to locals as well as the domestic animals of the area.