A province-based study using sampling method to investigate the prevalence of cystic echinococcosis among primary school children in Manisa, Turkey

Genetic diversity and haplotypes of paediatric hydatid cyst isolates and first occurrence of E. canadensis (G6/G7) in paediatric cases in Turkey

Cystic echinococcosis (CE) is a neglected zoonotic tropical disease caused by Echinococcus granulosus sensu lato. The aim of this study was to investigate the genetic variation of hydatid cyst isolates obtained from surgically confirmed paediatric cases originating from two different regions in eastern Turkey. Seventeen paediatric cases aged between 6 and 16 were operated by open surgery, and the germinal layers of their cysts were obtained for further molecular analyses. After genomic DNA isolation, 875 bp mt-CO1 gene fragments were amplified in all samples by PCR. Then, the unidirectional sequence analyses of the PCR products were carried out. According to the BLAST analyses of 17 sequences, 16 of these sequences were matched with E. granulosus sensu stricto, while one sequence was identified as E. canadensis (G6/G7) for the first time in paediatric cases in Turkey. High haplotype diversity and low nucleotide diversity were observed in the E. granulosus s.s. sequences.

Echinococcoses in Iran, Turkey, and Pakistan: Old Diseases in the New Millennium

Echinococcosis is considered a cosmopolitan zoonosis caused by different species of small taeniid tapeworms of the genus Echinococcus and is regarded as a neglected zoonosis. Cystic and alveolar echinococcoses are endemic diseases of Tibetan, Pamir, and Iranian plateaus. All of the countries within the Iranian plateau are affected by echinococcosis. Pakistan, Turkey, and Iran are the three most populous countries of the region, in which echinococcosis is highly endemic. The three neighboring countries share strong cultural and socioeconomic ties. The present study aimed to provide a broad review of the status of cystic and alveolar echinococcosis, summarizing the current knowledge about geographical distribution, molecular epidemiology, and transmission dynamics of Echinococcus granulosus sensu lato and Echinococcus multilocularis in this region. Additionally, we aimed to understand disease burden and risk factors as basic requirements for establishing a surveillance system and planning prevention and control programs. A considerable body of information is available on different aspects of echinococcosis in this region; however, several information and research gaps need to be filled before planning control programs. None of the countries in the region have an elaborate echinococcosis control program. Effective control programs require multi/intersectoral coordination within a One Health approach with a long-term political and administrative commitment and enhanced international collaboration among the three countries.

Source attribution of human echinococcosis: A systematic review and meta-analysis

BACKGROUND

A substantial proportion of echinococcosis transmission to humans via contamination of food has been assumed. However, the relative importance of food as a transmission vehicle has previously been estimated through expert opinion rather than empirical data.

OBJECTIVE

To find and evaluate empirical data that could be used to estimate the source attribution of echinococcosis, in particular the proportion that is transmitted through contaminated food.

METHODS

A systematic review was undertaken to identify reports on the risk factors for human cystic (CE) and alveolar (AE) echinococcosis. Data bases searched included PubMed, Scopus, Web of Knowledge, Cab Direct, Science Direct, Google Scholar, eLIBRARY.RU, CyberLeninka, CNKI and VIP. Search terms included Echinococc*, hydatid, epidemiology, logistic regression, risk factors, odds ratio, relative risk, risk factors. Reports, including grey literature where available, that had suitable data were selected and data were extracted. The main pathways of transmission were hypothesised to be contact with the definitive host, contaminated water, contaminated food and contaminated environment (other than food). For each study the attributable fraction for these potential sources of infection was calculated from the data presented. A meta-analysis was then undertaken to obtain pooled estimates for the relative contribution of these transmission pathways.

RESULTS

Data from 28 cross-sectional studies and 14 case-control studies were extracted. There was strong evidence for transmission by direct contact with dogs for both CE and AE. The estimated attributable fractions were 26.1% (CI 13.8%-39.6%) and 34.4% (CI 20.7% -48.2%) respectively. Transmission through contaminated water was estimated to be responsible for approximately 29.4% (CI 12.1%-51.7%) for CE and 24.8% (CI 10.6% to 42.6%) for AE. Contaminated food may be responsible for approximately 23.4% of CE cases (CI 2.1%-47.3%). Globally, there was insufficient evidence to conclude AE can be transmitted by food, although case control studies from low human incidence areas suggested that possibly 32.5% (CI 10.0%-53.2%) could be transmitted by food. There was also insufficient evidence that direct contact with foxes was a significant source of human disease. There were no suitable studies with a risk of environmental contact reported, but the residual attributable fraction thatwould likely include this pathway was approximately 21.1% for CE and 11.1% for AE.

CONCLUSIONS

The results support the hypothesis that dog contact and drinking contaminated water are major pathways of transmission of both CE and AE. For contaminated food, the results are less consistent, but suggest that it is an important transmission pathway and provide better evidence than expert elicitations as previously used.

The pattern of cystic echinococcosis in children in an endemic area in Morocco

Cystic echinococcosis is a parasitic infection of major public health concern. The infection is generally acquired during childhood and the disease incubation period can last many years. The occurrence and characteristics of the disease in children were not well studied. The present study aimed to explore the pattern and features of cystic echinococcosis in children in rural and urban environments in Morocco. A total of 338 children diagnosed and treated for cystic echinococcosis were investigated. The trend of the infection, risk and exposure factors and the distribution of the anatomic locations of cysts were studied. A non-uniform decrease in proportions of infected children was found. Children from rural environs had significantly higher infection rates than children from urban environs (p < 0.001). Males were significantly more infected than females. Children aged 7-11 years were the most affected. For cysts locations, single organ involvement was found in 94.4% of the children versus 5.6% with multi-organ localization. Despite control program, active transmission of echinococcosis still occurred in children and remains a major public health problem. The infection in younger population may have some features that need to be considered in the prevention and control programs in endemic areas.

Public health risks associated with food-borne parasites

Parasites are important food‐borne pathogens. Their complex lifecycles, varied transmission routes, and prolonged periods between infection and symptoms mean that the public health burden and relative importance of different transmission routes are often difficult to assess. Furthermore, there are challenges in detection and diagnostics, and variations in reporting. A Europe‐focused ranking exercise, using multicriteria decision analysis, identified potentially food‐borne parasites of importance, and that are currently not routinely controlled in food. These are Cryptosporidium spp., Toxoplasma gondii and Echinococcus spp. Infection with these parasites in humans and animals, or their occurrence in food, is not notifiable in all Member States. This Opinion reviews current methods for detection, identification and tracing of these parasites in relevant foods, reviews literature on food‐borne pathways, examines information on their occurrence and persistence in foods, and investigates possible control measures along the food chain. The differences between these three parasites are substantial, but for all there is a paucity of well‐established, standardised, validated methods that can be applied across the range of relevant foods. Furthermore, the prolonged period between infection and clinical symptoms (from several days for Cryptosporidium to years for Echinococcus spp.) means that source attribution studies are very difficult. Nevertheless, our knowledge of the domestic animal lifecycle (involving dogs and livestock) for Echinoccocus granulosus means that this parasite is controllable. For Echinococcus multilocularis, for which the lifecycle involves wildlife (foxes and rodents), control would be expensive and complicated, but could be achieved in targeted areas with sufficient commitment and resources. Quantitative risk assessments have been described for Toxoplasma in meat. However, for T. gondii and Cryptosporidium as faecal contaminants, development of validated detection methods, including survival/infectivity assays and consensus molecular typing protocols, are required for the development of quantitative risk assessments and efficient control measures.

Prevalence of abdominal cystic echinococcosis in rural Bulgaria, Romania, and Turkey: a cross-sectional, ultrasound-based, population study from the HERACLES project

BACKGROUND

Cystic echinococcosis is a neglected zoonotic infection that is distributed worldwide and prioritised by WHO for control efforts. The burden of human cystic echinococcosis is poorly understood in most endemic regions, including eastern Europe. We aimed to estimate the prevalence of abdominal cystic echinococcosis in rural areas of Bulgaria, Romania, and Turkey.

METHODS

We did a cross-sectional ultrasound-based survey that recruited volunteers from 50 villages in rural areas of Bulgaria, Romania, and Turkey. These villages were in provinces with annual hospital incidence of cystic echinococcosis within the mid-range for the respective countries. All people who attended a session were allowed to participate if they agreed to be screened. Abdominal ultrasound screening sessions were hosted in public community structures such as community halls, primary health-care centres, schools, and mosques. Lesions were classified using an adapted WHO classification. We reported the prevalence of abdominal cystic echinococcosis adjusted by sex and age through direct standardisation, using the country's rural population as a reference.

FINDINGS

From July 1, 2014, to Aug 3, 2015, 24 693 individuals presented to screening sessions and 24 687 underwent ultrasound screening. We excluded a further six indivduals due to missing data, leaving 24 681 people in our analysis. Abdominal cystic echinococcosis was detected in 31 of 8602 people screened in Bulgaria, 35 of 7461 screened in Romania, and 53 of 8618 screened in Turkey. The age and sex adjusted prevalence of abdominal cystic echinococcosis was 0·41% (95% CI 0·29-0·58) in Bulgaria, 0·41% (0·26-0·65) in Romania, and 0·59% (0·19-1·85) in Turkey. Active cysts were found in people of all ages, including children, and in all investigated provinces.

INTERPRETATION

Our results provide population-based estimates of the prevalence of abdominal cystic echinococcosis. These findings should be useful to support the planning of cost-effective interventions, supporting the WHO roadmap for cystic echinococcosis control.

FUNDING

European Union Seventh Framework Programme.

Case-series study of hepatic echinococcal cysts in Serbia: viability of scolices, seropositivity and epidemiological characteristics

Cystic echinococcosis (CE) is an endemic helminthic disease caused by infection with Echinococcus granulosus metacestodes. Although CE is endemic in the Balkan region, the exact epidemiology remains unknown. We conducted a case-series study with the aim of evaluating the correlation between seropositivity, socio-epidemiological data, pre-operative treatment with albendazole and viability of protoscolices in human hepatic hydatid cysts. Consecutive patients with hepatic CE underwent surgery to extract E. granulosis cysts. The viability of protoscolices was measured by their ability to absorb 0.1% eosin. Socio-epidemiological data were collected and serological testing was performed. In the present study, 38 patients (28 adults and 10 children) with hepatic CE were treated surgically. The scolex viability test was positive in 30/38 (79%) samples. All patients with non-viable cysts had seronegative results. The viability test was positive in 11/12 (91.6%) adult patients with pre-operative albendazole treatment and in 9/10 (90%) children. Statistically more patients were from an urban area compared with a rural area (65.8% vs. 15.7%). The increasing number of stray dogs shedding E. granulosus eggs in urban public areas in the Balkans might be the reason for the significant difference in the rate of infection between urban and rural areas in the present study. In addition, uncontrolled slaughtering of livestock, common in rural settlements, and feeding the infected viscera to dogs, favour the maintenance of the parasite cycle. We believe that the results of our study will encourage physicians, veterinarians and health authorities to initiate a programme to prevent and control CE in the Balkan region.

Epidemiology of Echinococcosis Among Schoolchildren in Golog Tibetan Autonomous Prefecture, Qinghai, China

Echinococcosis is a serious zoonotic parasitic disease that is highly endemic in Qinghai Province. The present study aimed to investigate the prevalence of echinococcosis among schoolchildren in Golog Tibetan Autonomous Prefecture to improve early diagnosis and treatment of patients and to provide information for echinococcosis prevention and control. A total of 11,260 schoolchildren from five counties (Maqin, Gander, Dari, Jiuzhi, and Banma) in Golog Tibetan Autonomous Prefecture, Qinghai Province, were screened for echinococcosis. Screening involved ultrasound imaging combined with serologic examination as an auxiliary diagnostic test. The prevalence of echinococcosis in the schoolchildren was 2.1% (235/11,260), with a rate of 0.8% for cystic echinococcosis (CE; 89/11,260) and 1.3% for alveolar echinococcosis (AE; 146/11,260). Additionally, one child had a mixed infection. The prevalence ranged between 1.1% and 4.1% among the five investigated counties, and was highest in Dari County (4.1%). The prevalence of echinococcosis was higher in girls than in boys and gradually increased with age. In addition, children with CE mainly had type 1 (CE1) and type 3 (CE3) lesions, and children with AE mainly had small-diameter calcified lesions, suggesting that they were in the early asymptomatic stage of echinococcosis. In conclusion, children of Golog Tibetan Autonomous Prefecture appear to exhibit the highest recorded prevalence of CE and AE globally. Ultrasound is useful for screening populations in regions where both CE and AE are endemic.

Global Distribution of Alveolar and Cystic Echinococcosis

Alveolar echinococcosis (AE) and cystic echinococcosis (CE) are severe helminthic zoonoses. Echinococcus multilocularis (causative agent of AE) is widely distributed in the northern hemisphere where it is typically maintained in a wild animal cycle including canids as definitive hosts and rodents as intermediate hosts. The species Echinococcus granulosus, Echinococcus ortleppi, Echinococcus canadensis and Echinococcus intermedius are the causative agents of CE with a worldwide distribution and a highly variable human disease burden in the different endemic areas depending upon human behavioural risk factors, the diversity and ecology of animal host assemblages and the genetic diversity within Echinococcus species which differ in their zoonotic potential and pathogenicity. Both AE and CE are regarded as neglected zoonoses, with a higher overall burden of disease for CE due to its global distribution and high regional prevalence, but a higher pathogenicity and case fatality rate for AE, especially in Asia. Over the past two decades, numerous studies have addressed the epidemiology and distribution of these Echinococcus species worldwide, resulting in better-defined boundaries of the endemic areas. This chapter presents the global distribution of Echinococcus species and human AE and CE in maps and summarizes the global data on host assemblages, transmission, prevalence in animal definitive hosts, incidence in people and molecular epidemiology.

Higher seroprevalence of hepatitis B virus antigen in patients with cystic hydatid disease than in patients referred to internal medicine clinics in Turkey

Turkey remains an intermediate area for prevalence of hepatitis B virus (HBV) surface antigenemia. The sheep-raising areas of Turkey also pose a high risk for cystic hydatid disease (CHD). Both HBV infection and CHD are major public health issues particularly in eastern parts of Turkey; however, there is no data regarding HBV infection in patients who have had CHD. The aims of this study were to evaluate the association between HBV infection and CHD and suggest ways to reduce HBV infection which is still widespread in Turkey. A retrospective study was conducted with 94 adult patients with active CHD referred to the hepatology department, Yuzuncuyil University School of Medicine from December 2010 to December 2012. All subjects came from rural areas of the region and underwent ultrasonography of abdomen which detected CHD of the liver. All the patients were serologically positive for Echinococcus granulosus. The control group consisted of 500 patients (300 men and 200 women) referred to the internal medicine clinics for other reasons. The patients with CHD and in the control group were tested for the existence of HBs antigen according to the standard procedures. The seroprevalence of HBs antigen was significantly higher in patients with active CHD than those in the control group (12.7% vs 5.2%; P=0.0017). Our data indicate that there is significant association between HBV infection and CHD. All patients with CHD should be screened for HBV infection.

A mass screening survey of cystic echinococcosis by ultrasonography, Western blotting, and ELISA among university students in Manisa, Turkey

Cystic echinococcosis (CE) is one of the most important zoonotic diseases in a wide geographic area, including Turkey. In the present project, a total of 4275 students from Celal Bayar University, Manisa, Turkey, were screened by ultrasonography (US) and specific antibodies for CE were examined by Western blotting (WB) and ELISA in finger prick blood samples of 2034 of 4275 volunteered students. We aimed to report the apparent prevalence of CE based on different diagnostic procedures and to compare WB and ELISA with US in diagnosis of CE in a mass screening setting. Six new cases were diagnosed as CE by US during the survey. In addition to these cases, three students were also detected to have been previously operated and pathologically confirmed for hepatic CE. US revealed parenchymal changes in these cases in concordance with their operation history; so, the prevalence of CE by US was calculated as 0.21% (9/4275) (95%CI, 0.11-0.39%) among university students in Manisa. Bands were detected at 8, 28, 32, 38, 42, 47, 70 and 90kDa by WB and the cases were considered to be positive for CE when at least three of the bands were seen together. Apparent prevalence of CE by ELISA and WB were found to be 2.11% (43/2034) (95%CI, 1.57-2.83%) and 0.25% (5/2034) (95%CI, 0.10-0.57%), respectively. Of the six US positive cases, WB was positive in only one case with two cysts in the liver. All of four cases with liver involvement were positive by ELISA. The high prevalence of CE among university students in Manisa indicated that CE is a major health problem in this area of Turkey. Our results supported that WB is rather difficult and not feasible as a mass screening test and may not be effective for confirmation especially in asymptomatic cases. As a result, we recommend US to be used initially in mass screening surveys for CE followed by confirmation by ELISA for suspected cases. Further examination primarily by chest X-ray followed by computed tomography and/or magnetic resonance imaging, if needed, should be recommended for US negative, ELISA and WB positive individuals who may have non-abdominal cysts.

Skeletal manifestations of hydatid disease in Serbia: demographic distribution, site involvement, radiological findings, and complications

Although Serbia is recognized as an endemic country for echinococcosis, no information about precise incidence in humans has been available. The aim of this study was to investigate the skeletal manifestations of hydatid disease in Serbia. This retrospective study was conducted by reviewing the medical database of Institute for Pathology (Faculty of Medicine in Belgrade), a reference institution for bone pathology in Serbia. We reported a total of 41 patients with bone cystic echinococcosis (CE) during the study period. The mean age of 41 patients was 40.9±18.8 years. In 39% of patients, the fracture line was the only visible radiological sign, followed by cyst and tumefaction. The spine was the most commonly involved skeletal site (55.8%), followed by the femur (18.6%), pelvis (13.9%), humerus (7.0%), rib (2.3%), and tibia (2.3%). Pain was the symptom in 41.5% of patients, while some patients demonstrated complications such as paraplegia (22.0%), pathologic fracture (48.8%), and scoliosis (9.8%). The pathological fracture most frequently affected the spine (75.0%) followed by the femur (20.0%) and tibia (5.0%). However, 19.5% of patients didn't develop any complication or symptom. In this study, we showed that bone CE is not uncommon in Serbian population. As reported in the literature, therapy of bone CE is controversial and its results are poor. In order to improve the therapy outcome, early diagnosis, before symptoms and complications occur, can be contributive.

A systematic review of the literature on cystic echinococcosis frequency worldwide and its associated clinical manifestations

A systematic literature review of cystic echinoccocosis (CE) frequency and symptoms was conducted. Studies without denominators, original data, or using one serological test were excluded. Random-effect log-binomial models were run for CE frequency and proportion of reported symptoms where appropriate. A total of 45 and 25 articles on CE frequency and symptoms met all inclusion criteria. Prevalence of CE ranged from 1% to 7% in community-based studies and incidence rates ranged from 0 to 32 cases per 100,000 in hospital-based studies. The CE prevalence was higher in females (Prevalence Proportion Ratio: 1.35 [95% Bayesian Credible Interval: 1.16-1.53]) and increased with age. The most common manifestations of hepatic and pulmonary CE were abdominal pain (57.3% [95% confidence interval [CI]: 37.3-76.1%]) and cough (51.3% [95% CI: 35.7-66.7%]), respectively. The results are limited by the small number of unbiased studies. Nonetheless, the age/gender prevalence differences could be used to inform future models of CE burden.

A portable ultrasound based screening study on the prevalence and risk factors of cystic echinococcosis in primary school children in East Turkey

The tapeworm Echinococcus granulosus constitutes a major public health concern, since its larval stage causes cystic echinococcosis (CE) which is a life-threatening zoonotic disease in many parts of the world. The purpose of the present study was to perform a screening study in order to investigate the prevalence and risk factors of CE using a portable ultrasound (US) in a representative sample of 2500 primary school children aged 7-14 in East Turkey, where CE is known to be endemic. The students were scanned by portable US while standing, with special attention to the liver, spleen, pancreas, and kidneys. The US scan was followed by a physical examination. In addition, a questionnaire was distributed to all students for completion with the assistance of their teachers regarding their demographic and social characteristics as well as their hygienic habits possibly related to CE. Students found positive were subjected to serologic examination. The US based prevalence was 0.2%. Organ involvement was 0.12% for liver and 0.08% for kidney. The response rate of the questionnaire survey was 93%. The risk factors found to be significant (P<0.05) for CE infection were hand washing and family relative with CE. The results of this study indicate that CE infection is an important public health problem in East Turkey requiring appropriate control measures.

Diagnosis and management of hydatid liver disease in children: a report of 156 patients with hydatid disease

BACKGROUND/PURPOSE

There are many published reviews on adult hydatid disease and a guideline published by World Health Organization Informal Working Group (WHO-IWGE) in 2010. However, there are very few reports on hydatid liver disease in children with limited numbers of patients, and no comments were offered on childhood hydatid liver disease in the WHO-IWGE 2010 guideline. The aim of this study is to present our 17-year experience with 156 pediatric patients with hydatid liver disease and provide a treatment algorithm for children.

METHODS

The clinical records of 156 children with hydatid liver disease treated from January 1994 to January 2011 were retrospectively reviewed. Patient sex, age at diagnosis, symptoms, disease location, cyst numbers and sizes, treatment choices, medical treatment duration, surgical methods, and complications were recorded. Treatment of liver hydatidosis included 3 different schedules: (1) small (<5 cm) liver cysts treated with albendazole (ABZ) only, (2) cysts (>5 cm) located at the liver surface treated with surgery combined with ABZ, and (3) all (>5 cm) liver cysts embedded deep in the liver parenchyme treated with percutaneous drainage and ABZ. Albendazole was given (10 mg/kg twice a day) and continued for 6 months after initial therapy.

RESULTS

There were 92 boys and 64 girls with an average age of 9.2 years (range, 1.1-15 years). A total of 376 cysts were detected in 156 patients. The follow-up period ranged from 1 to 10 years (median, 6.5 years). Complications were classified according to the Dindo classification. After the first 6 months of therapy, grade I complications occurred in 12.1% of patients, grade II complications in 7.4%, and grade IIIb complications in 7.3%. There were no grade IIIa, IVa, or IVb complications. At 1 year, grade II complications were recorded in 9.6% of 15 patients, and grade IIIb complications, in 1.2% of patients. During the 17 years reviewed, there were no mortalities (0% grade V complications).

CONCLUSIONS

Based on this experience, we believe that suitable treatment should be chosen based on factors such as cyst number, cyst location (on the surface or deep in the organ), proximity to vascular structures, whether the cyst is complicated, and additional organ involvement or not. In addition, although the results of our study mostly agree with the results in the WHO-IWGE 2010 report, there are some noticeable differences between these 2 studies. Hence, we believe that the WHO-IWGE 2010 recommendations should be updated by incorporating the childhood observations.

Cystic echinococcosis in children - the seventeen-year experience of two large medical centers in Serbia

Cystic echinococcosis (CE) is a public health problem in countries having such endemic areas. Epidemiological studies of CE, especially pediatric, are rare. The aim of this study was to evaluate epidemiological and clinical characteristics of CE in children in Serbia. Data were obtained retrospectively from the case records of patients under the age of 18 years admitted for surgical treatment of CE at two large pediatric medical institutions in the period 1990-2006. Patients' age, number of cysts and their anatomic location were evaluated in relation to differences by patients' gender and socio-geographic status (urban or rural origin). The study included 149 children with 272 hydatid cysts. The mean age of patients was 10.1+/-3.8 years. There were no significant differences in the number of patients in relation to gender and urban:rural origin. There were no significant differences in patients' age at the time of surgery or the number of cysts per patient when patients' gender or socio-geographic status was evaluated. The anatomic location of cysts was as follows: liver (N=165; 60.7%), lungs (N=82; 30.1%), and other locations (N=25; 9.2%). Multiple cysts, and combined liver/lung involvement were identified in 34.2% (N=51), and 6.0% (N=9) of patients, respectively. Hepatic cysts were significantly more common in girls than in boys. There were no significant differences in anatomic location of cysts between socio-geographic groups. The large number of infected children during a long period of investigation indicates an active transmission of disease and a lack of program for control and prevention of CE in Serbia.