Echinococcosis with Particular Reference to Southeast Asia

Cystic echinococcosis of the bone

PURPOSE OF REVIEW

Cystic echinococcosis (CE) has a wide world distribution causing important morbidity. Osseous involvement is present in less than 4% of the CE cases. Its diagnosis and therapeutic management is full of challenges and low grade of evidence.

RECENT FINDINGS

The study summarizes literature evidence on the management of osseous CE with particular emphasis on new data regarding diagnosis and treatment.

SUMMARY

Clinical presentation of osseous CE depends on the skeletal area affected. Diagnosis is mostly based on radiological findings and serology. Recent advances with qPCR on osseous tissue samples seem to be a good option for diagnosis confirmation. Complete resection of the cystic lesion is the only curative option, but it is usually not possible performing palliative surgery and prolonged albendazole intake in most cases. Radiotherapy could be an option, but experience to date is only based on clinical cases.

Molecular characterization and serodiagnostic evaluation of the Echinococcus ortleppi recombinant glutaredoxin 1 protein for cystic echinococcosis in buffalo (Bubalus bubalis)

Cystic echinococcosis (CE), caused by the metacestode of Echinococcus granulosus sensu lato (s.l.), adversely affects the physiology of the vital organs in which they grow. Condemnation of meat causes substantial economic loss to the livestock industry. Conventionally the infection is detected by necropsy as serological diagnosis of the infection in livestock is ambiguous. Identification of specific diagnostic antigens would be a substitute for the cyst fluid antigens which lack adequate diagnostic sensitivity and specificity. BLAST analysis supported by the negligible pairwise nucleotide distance of the 389 nt COX1, 489 nt NAD1, and 425 nt ITS1 with the related sequences of E. ortleppi ascertained the association of E. ortleppi with CE in buffaloes. Given the extensive distribution of glutaredoxin 1 in every developmental stage of Echinococcus granulosus s.l that makes it an ideal serodiagnostic antigen for CE, we expressed the 14 kDa E. ortleppi glutaredoxin 1 (rEoGrx1) protein in E. coli BL21 (DE3) and tested a total of 225 sera samples, including 126 sera samples from the necropsy-positive buffalo, by the rEoGrx1 IgG-ELISA. The ELISA could detect a total of 82/126 sera samples as positive. The diagnostic sensitivity and specificity of the rEoGrx1 IgG-ELISA were 65.1 % and 51.5 %, respectively. The protein showed serological cross-reaction against Fasciola gigantica, Toxoplasma gondii, and Sarcocystis sp. The in silico bioinformatics analysis of the E. ortleppi, F. gigantica, and T. gondii glutaredoxin sequences revealed fully conserved amino acids at positions 11 and 21, the substitution of conserved amino acids at positions 14 and 6, and semi-conserved substitutions at positions 3 and 4, respectively. The findings partly explain the molecular basis of the serological cross-reactivity of the protein.

Introductory Chapter: Changes in Eco-System Change Echinococci - “One Health Concept” against Echinococci

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Community Based Assessment of Behavior and Awareness of Risk Factors of Cystic Echinococcosis in Major Cities of Pakistan: A One Health Perspective

Background: The parasitic disease, cystic echinococcosis (CE), is a serious health problem in Pakistan. Risk of disease transmission is increased by economic and political instability, poor living conditions, and limited awareness of hygienic practices. The current study aimed to investigate the community perception and awareness regarding the risk factors of CE in Pakistan, from a One Health perspective. Methods: We conducted a community-based survey involving 454 participants in the major cities of Pakistan. Quantitative data based on knowledge, attitude, and practices (KAP), the One Health concept, risk factors, and community perception of CE among the general population of the major cities of Pakistan were collected. The questions included those related to knowledge, attitude, practices, One Health concept, risk factors, and community perception. The Chi-squared test was applied to determine the associations regarding KAPs across socio-demographic parameters. Results: KAPs had no significant associations with sociodemographic aspects such as age, sex, religion, ethnicity, education, marital status, occupation, or financial status of the participants. The findings indicated a lack of awareness about CE among the participants. Respondents were unaware of the risk factors and the One Health concept of CE. However, the community attitude and perception were positive toward the control of CE. Conclusion: Illiteracy, deficient sanitation systems and lack of awareness are the contributing factors to CE in Pakistan. It is necessary to make the community aware regarding CE and its importance. Increasing this awareness represents an important step toward the eradication and control of CE.

Molecular characterization of sheep and human isolates of Echinococcus granulosus from temperate region of India

The aim of the present study was to investigate Echinococcus granulosus genotypes in the Kashmir valley. A total of 2,100 sheep and human patients were screened for the presence of hydatidosis. Total 87 isolates were collected, 85 from sheep and 2 isolates from human beings. The rDNA-ITS1 fragment were amplified with BD1 / 4S primers. In addition, fragments of genes coding for ITS1 were sequenced. The length of amplified fragment for all isolated samples with sheep origin was 1,000 bp and with human origin was between 1,000 bp and 1,100 bp. The products on digestion with restriction enzymes Rsa 1, Alu 1, Msp 1 yielded identical fragments, 300 and 700 bp in sheep and 325 and 700 bp in humans. Intact 1000 bp fragment was observed with Taq 1. The molecular findings reveal that sheep strain (G1) is the predominant genotype in sheep and humans in Kashmir valley.

Effects of geographical and climatic factors on cystic echinococcosis in south-western Iran

Cystic echinococcosis (CE) is caused by the larval form of Echinococcus granulosus that can cause serious health and economic problems in the endemic foci. CE is globally distributed in various climatic conditions from circumpolar to tropical latitudes. Iran is an important endemic area with a spectrum of weather conditions. The aim of this study was to determine the effects of geo-climatic factors on the distribution of livestock CE in south-western Iran (SWI) in 2016 to 2018. Data of livestock CE were retrieved from veterinary organizations of four provinces of SWI. The geo-climatic factors, including mean annual temperature (MAT), minimum MAT (MinMAT), maximum MAT (MaxMAT), mean annual rainfall (MAR), elevation, mean annual evaporation (MAE), sunny hours, wind speed, mean annual humidity (MAH), slope, frost days and land cover, were analysed using geographical information systems (GIS) approaches. The statistical analysis showed that MAR, frost days, elevation, slope and semi-condensed forest land cover were positively and MAE, MAT, MaxMAT, MinMAT and salt and salinity land cover were negatively correlated with CE occurrence. MAE was shown to be a predictive factor in the stepwise linear logistic regression model. In short, the current GIS-based study found that areas with lower evaporation were the main CE risk zones, though those with lower temperature and higher rainfall, altitude and slope, especially where covered with or in close proximity of semi-condensed forest, should be prioritized for consideration by health professionals and veterinarians for conducting control programmes in SWI.

Human cystic echinococcosis in southwest Iran: a 15-year retrospective epidemiological study of hospitalized cases

Background

Cystic echinococcosis (CE) is considered as a neglected disease with significant mortality and morbidity in most of the developing countries. The current study aimed to retrospectively assess the demographic and epidemiologic features of human CE surgical cases in a 15-year period in Fars province, southwestern Iran.

Methods

A 15-year (2004–2018) retrospective study was conducted to find out the epidemiological and clinical picture of CE in patients who undergone surgeries for CE in two main hospitals in Fars Province, southwestern Iran. Hospital records were reviewed, and data were retrieved from each CE patient’s record.

Results

A total of 501 CE surgical cases were recorded during a 15-year period, corresponding to an average annual incidence of 33.4 and a surgical incidence rate of 0.74/100,000 population. Of these, 242 (48.6%) were male, and 256 (52.4%) were female. Patients’ age ranged from 2 to 96 years, with a mean age of 34.92 (± 19.87) years. A significantly higher rate of CE cases was noted in subject’s ≥ 50 years of age. The highest frequency of cases (62:12.5%) was recorded in the year 2017. The most commonly involved organs were liver (339 cases; 57.8%) and lung (279 cases; 47.6%). Concurrent involvement of two organs was seen in 58 (9.9%) cases of both lung and liver, 10 (1.6%) cases of lung and other locations (but not liver), and 23 (3.9%) cases of liver and other locations (but not lung). Reoperation was noted in 67 (13.4%) of the cases. The size of the lung hydatid cyst varied, ranging between 2 and 24 cm (mean = 7.33, SD = 3.737). The size of liver hydatid cysts ranged from 1 to 26 cm (mean 9.04, SD = 4.275).

Conclusion

The findings of the current study demonstrated a nearly constant prevalence of CE during the last 15 years in southern Iran. Further studies are needed to find out the reasons behind the recurrence of the disease, which is substantial, in surgically-treated patients.

Echinococcosis transmission on the Tibetan Plateau

Since the mid-1990s detailed studies and field investigations on the Tibetan Plateau have revealed human echinococcosis to be an under-reported major public health problem, particularly in the dominant pastoral communities in the eastern and central regions. Human prevalence surveys showed that cystic echinococcosis (CE, caused by Echinococcus granulosus) and alveolar echinococcosis (AE, caused by Echinococcus multilocularis) are co-endemic with higher burdens of each disease than other endemic world regions. Epidemiological investigations identified some major risk factors for human CE and AE including dog ownership, husbandry practices and landscape features. Dogs appear to be the major zoonotic reservoir for both E. granulosus and E. multilocularis, but the latter is also transmitted in complex wildlife cycles. Small mammal assemblages especially of vole and pika species thrive on the Plateau and contribute to patterns of E. multilocularis transmission which are influenced by landscape characteristics and anthropogenic factors. Tibetan foxes are a principal definitive host for both E. multilocularis and E. shiquicus. In 2006 a national echinococcosis control programme was initiated in Tibetan communities in northwest Sichuan Province and rolled out to all of western China by 2010, and included improved surveillance (and treatment access) of human disease and regular deworming of dogs with annual copro-testing. Control of echinococcosis in Tibetan pastoral communities poses a difficult challenge for delivery and sustainability.

Osseous cystic echinococcosis: A case series study at a referral unit in Spain

Background

Cystic echinococcosis (CE) is present in all continents, except for the Antarctica. Characteristically, CE lesions are found in the liver and the lungs, but virtually any part of the body may be affected (the spleen, kidneys, heart, central nervous system, bones, among others). It is estimated that the incidence of bone involvement in CE is 0.5% to 4%.

Methodology

A retrospective study was performed of patients with osseous CE treated at the National Reference Unit of Tropical Diseases of the Ramon y Cajal Hospital, Madrid, Spain, between 1989 and December 2017. Epidemiological, clinical, diagnostic and therapeutic data of patients with long-term follow-up were collected.

Main findings

During the study period, of the 104 patients with CE, 27 exhibited bone involvement (26%). The bones most frequently affected were the spine, followed by the ribs, pelvis, femur, tibia and the scapula. The most common symptom was pain followed by medullar syndrome and pathologic fracture. In total, 81.5% of patients underwent surgery for osseous CE at least once. As many as 96% received albendazol either in (mostly long-term) monotherapy or in combination with praziquantel.

Conclusions

The diagnosis and management of osseous CE is challenging. In many cases osseous CE should be considered a chronic disease and should be managed on a case-by-case basis. Lifelong follow-up should be performed for potential recurrence and sequels.

Echinococcosis occurs in humans as a result of infection by a cestodes of the genus Echinococcus. One of the species, E. granulosus, causes cystic echinococcosis (CE) in humans worldwide. In the lifecycle there is a definitive host (generally dogs) which host this parasites at the small bowel. From there, ground is shed with the eggs of the parasite through feces and the intermediate host (usually a sheep or other herbivores get infected). Humans act as an incidental intermediate host when they become infected through the consumption of water or food contaminated with Echinococcus eggs. Once the egg has been ingested, it penetrates the intestinal mucosa and through the circulatory system finds an anatomical site forming a cystic lesion (hydatid or hydatid cyst). Characteristically, CE are found in the liver and the lungs, but virtually any part of the body may be affected. Incidence of osseous CE is low, its diagnosis and management is challenging and there is little information published. In this study we report our experience at a referral unit during nearly 30 years in the management of a series of patients with osseous CE. Such information may be useful for other physicians when treating osseous CE.

Gene-based molecular analysis of COX1 in Echinococcus granulosus cysts isolated from naturally infected livestock in Riyadh, Saudi Arabia

The diversity and importance of Echinococcus species in domesticated animals in Saudi Arabia are poorly understood. In this study, 108 singular (hydatid) cysts were collected from goats (n = 25), sheep (n = 56) and camels (n = 27). DNA was extracted from the protoscoleces of individual fertile cysts and used for polymerase chain reaction (PCR) amplification of mitochondrial subunit 1 of the cytochrome c oxidase 1 (cox1) gene. Amplicon sequencing results revealed the presence of Echinococcus granulosus sensustricto (s.s.) (genotypes G1–G3) in 16 of the17 sheep cysts and 2 of the 27 camel cysts.of these samples, 18 (2 camel and 16 sheep) were divided into genotypes G1, G2, and G3.

Management of osseous cystic echinococcosis

INTRODUCTION

Osseous cystic echinococcosis (CE) is one of the most complicated and devastating conditions caused by Echinococcus granulosus. Its management is difficult and there is scant literature about it. Areas covered: A literature review was performed to provide an update on its diagnosis, treatment and follow-up. Expert commentary: In most cases diagnosis of osseous CE can only be confirmed by surgery. Osseous CE should be managed by experienced physicians and addressed as a chronic disease with therapies must be aimed at controlling the disease and its sequels or complications, rather than with a curative intent.

Immunization of sheep against Echinococcus granulosus with protoscolex tegumental surface antigens

AIM

Cystic echinococcosis (CE) has potential economic effects to both animal products and human health. A vaccine to protect livestock against CE can be effective in reducing economic costs and increasing the livestock products. Protoscolex tegumental surface antigens (PSTSA) used to induce the production of specific antibodies against Echinococcus granulosus in sheep. The tegumental antigens were extracted from viable protoscolices by solubilization in sterile phosphate-buffered saline containing decanoyl-N-methylglucamine.

MATERIALS AND METHODS

Ten lambs which were infected with CE (positive control), 10 negative control, and 10 test groups of sheep were included in the study. 300 µg emulsion of purified-PSTSA was injected intramuscularly in a two-step immunization on the first and 30 days. Sera were collected immediately before immunization and 6 times with 10-day intervals until 60 days post immunization. Thereafter, the sera were tested for antibodies by indirect hemagglutination test in microtiter plate.

RESULTS

After two immunizations, all the infected animals in test group showed substantial increases in antibody titer. Statistical analysis showed a significant difference between the titer obtained in the test and negative control groups in both phases of immunization (p<0.05).

CONCLUSION

The results showed that the PSTSA is a promising immunogenic compound for immunization of sheep against CE.

Prevalence of cystic echinococcosis in Iran: a systematic review and meta-analysis

As a significant zoonosis, cystic echinococcosis (CE) is endemic in some parts of the world, such as the Middle East. There are studies on the prevalence of this infection in animal and human reservoirs in Iran; hence, we conducted this meta-analysis to elucidate the prevalence of CE in Iran. English (PubMed, Scopus, Web of Science, Science Direct and Google Scholar) and Persian (Magiran, Iran Medex, Iran Doc and SID) databases were explored. In the case of definitive, animal and human intermediate hosts, 37, 90 and 33 studies, respectively, have been included in the current review from January 1990 to December 2015. According to outcomes of the heterogeneity test, either Der Simonian and Laird's random-effects method or Mantel–Haenszel's fixed-effects method were employed to pool the estimations. The pooled prevalence ofEchinococcus granulosusinfection in definitive hosts was calculated as 23.6% (95% confidence interval (CI) = 17.6–30.1%). The weighted prevalence of animal and human hydatidosis was calculated as 15.6% (95% CI = 14.2–17.1%) and 4.2% (95% CI = 3.0–5.5%), respectively. Meanwhile, most cases of human hydatidosis were in southern Iran, with a prevalence of 5.8% (3.2–9.2%). In terms of human hydatidosis, more infections were found in rural regions, and mostly in female individuals. Egger's regression test revealed publication bias, with a remarkable impact on total prevalence of the infection in animal intermediate hosts (P< 0.001), while it was not significant in human hosts (P= 0.4) and definitive hosts (P= 0.3). According to the weighted estimated prevalence of cystic echinococcosis and its financial burden, implementing appropriate control programmes should be compulsory to decrease the burden of the disease in Iran.

Isolated pulmonary hydatid cyst: Misinterpreted as metastatic pulmonary lesion in an operated case of carcinoma breast in young female

Hydatidosis is caused by Echinococcus granulosus. Humans may be infected incidentally as intermediate host by the accidental consumption of soil, water, or food contaminated by fecal matter of an infected animal. Hydatidosis is one of the most symptomatic parasitic infections in various livestock - raising countries. Lung is the second most commonly affected organ following the liver. The symptoms depend on the size and site of the lesion. It can present as an asymptomatic pulmonary lesion to hemoptysis, chest pain, coughing anaphylaxis, and shock. There are very few reported cases of isolated lung hydatidosis without exposure to animals or nonvegetarian diet. For hydatidosis, serology and imaging are diagnostic tools. Surgical removal and/or chemotherapy are the main-stay of treatment. Here, we discuss a case of persistent left lower lobe cystic lesion in young female with a history of operated left breast carcinoma which was thought to be of metastatic lesion but ultimately confirmed as pulmonary hydatid cyst after unintended aspiration of cystic fluid to rule out malignancy. Pulmonary hydatidosis should always be considered as a differential diagnosis when dealing with a cystic lesion on radiology.

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.

Ecology and Life Cycle Patterns of Echinococcus Species

The genus Echinococcus is composed of eight generally recognized species and one genotypic cluster (Echinococcus canadensis cluster) that may in future be resolved into one to three species. For each species, we review existing information on transmission routes and life cycles in different geographical contexts and - where available - include basic biological information of parasites and hosts (e.g., susceptibility of host species). While some Echinococcus spp. are transmitted in life cycles that involve predominantly domestic animals (e.g., dog - livestock cycles), others are wildlife parasites that do or do not interact with domestic transmission. In many cases, life cycle patterns of the same parasite species differ according to geography. Simple life cycles contrast with transmission patterns that are highly complex, involving multihost systems that may include both domestic and wild mammals. Wildlife transmission may be primary or secondary, i.e., resulting from spillovers from domestic animals. For most of the species and regions, existing information does not yet permit a conclusive description of transmission systems. Such data, however, would be highly relevant, e.g., for anticipation of geographical changes of the presence and frequency of these parasites in a warming world, or for initiating evidence-based control strategies.

Characterisation of Antigen B Protein Species Present in the Hydatid Cyst Fluid of Echinococcus canadensis G7 Genotype

The larva of cestodes belonging to the Echinococcus granulosus sensu lato (s.l.) complex causes cystic echinococcosis (CE). It is a globally distributed zoonosis with significant economic and public health impact. The most immunogenic and specific Echinococcus-genus antigen for human CE diagnosis is antigen B (AgB), an abundant lipoprotein of the hydatid cyst fluid (HF). The AgB protein moiety (apolipoprotein) is encoded by five genes (AgB1-AgB5), which generate mature 8 kDa proteins (AgB8/1-AgB8/5). These genes seem to be differentially expressed among Echinococcus species. Since AgB immunogenicity lies on its protein moiety, differences in AgB expression within E. granulosus s.l. complex might have diagnostic and epidemiological relevance for discriminating the contribution of distinct species to human CE. Interestingly, AgB2 was proposed as a pseudogene in E. canadensis, which is the second most common cause of human CE, but proteomic studies for verifying it have not been performed yet. Herein, we analysed the protein and lipid composition of AgB obtained from fertile HF of swine origin (E. canadensis G7 genotype). AgB apolipoproteins were identified and quantified using mass spectrometry tools. Results showed that AgB8/1 was the major protein component, representing 71% of total AgB apolipoproteins, followed by AgB8/4 (15.5%), AgB8/3 (13.2%) and AgB8/5 (0.3%). AgB8/2 was not detected. As a methodological control, a parallel analysis detected all AgB apolipoproteins in bovine fertile HF (G1/3/5 genotypes). Overall, E. canadensis AgB comprised mostly AgB8/1 together with a heterogeneous mixture of lipids, and AgB8/2 was not detected despite using high sensitivity proteomic techniques. This endorses genomic data supporting that AgB2 behaves as a pseudogene in G7 genotype. Since recombinant AgB8/2 has been found to be diagnostically valuable for human CE, our findings indicate that its use as antigen in immunoassays could contribute to false negative results in areas where E. canadensis circulates. Furthermore, the presence of anti-AgB8/2 antibodies in serum may represent a useful parameter to rule out E. canadensis infection when human CE is diagnosed.

Cystic echinococcosis (CE), a worldwide-spread zoonosis, affects livestock mammals and humans with significant economic and public health impact. It is caused by the infection with the larva of cestodes belonging to Echinococcus granulosus complex, a series of parasite species with preference for different hosts. Among them, Echinococcus canadensis larva uses mainly camels, goats and pigs as hosts. Species/genotypes belonging to E. canadensis are considered the second most common cause of human CE, but its contribution may be underestimated since causes asymptomatic or more benign infections than other E. granulosus complex species. The most relevant antigen for CE diagnosis is a lipoprotein called antigen B (AgB). AgB antigenicity is linked to its protein moiety that is encoded by several genes. One of these genes, AgB2, seems to be differentially expressed within E. granulosus complex. Using high sensitivity proteomic tools we analysed the composition of AgB obtained from E. canadensis larva, detecting the protein products of all AgB genes, except AgB2. Since AgB subunits have been widely used as antigens in immunoassays for human CE diagnosis, our results indicate that using AgB2 protein product in these assays may lead to false-negative results, particularly in geographical areas where E. canadensis species/genotypes circulate.

Echinococcosis: Control and Prevention

Human cystic echinococcosis (CE) has been eliminated or significantly reduced as a public health problem in several previously highly endemic regions. This has been achieved by the long-term application of prevention and control measures primarily targeted to deworming dogs, health education, meat inspection, and effective surveillance in livestock and human populations. Human CE, however, remains a serious neglected zoonotic disease in many resource-poor pastoral regions. The incidence of human alveolar echinococcosis (AE) has increased in continental Europe and is a major public health problem in parts of Eurasia. Better understanding of wildlife ecology for fox and small mammal hosts has enabled targeted anthelmintic baiting of fox populations and development of spatially explicit models to predict population dynamics for key intermediate host species and human AE risk in endemic landscapes. Challenges that remain for echinococcosis control include effective intervention in resource-poor communities, better availability of surveillance tools, optimal application of livestock vaccination, and management and ecology of dog and wildlife host populations.

The Increase of Exotic Zoonotic Helminth Infections: The Impact of Urbanization, Climate Change and Globalization

Zoonotic parasitic diseases are increasingly impacting human populations due to the effects of globalization, urbanization and climate change. Here we review the recent literature on the most important helminth zoonoses, including reports of incidence and prevalence. We discuss those helminth diseases which are increasing in endemic areas and consider their geographical spread into new regions within the framework of globalization, urbanization and climate change to determine the effect these variables are having on disease incidence, transmission and the associated challenges presented for public health initiatives, including control and elimination.

Primary Giant Splenic Echinococcal Cyst Treated by Laparoscopy

Cystic echinococcosis (CE) is a zoonosis caused by the larval stage of the dog tapeworm Echinococcus granulosus. Liver and lungs are the most commonly affected organs whereas splenic infection is rarer and its primary involvement occurs in less than 2% of abdominal CE. We report a case of primary giant splenic hydatid cyst in a 75-year-old Peruvian woman that was laparoscopically removed without any complications, perioperative prophylactic chemotherapy with albendazole 400 mg twice a day 5 days before, and 7 days after the surgical procedure was administered, postoperative recovery was uneventful, and; at her 3-month follow-up the patient remains asymptomatic and an abdominal computed tomography scan demonstrated a cystic cavity of 15 cm diameter with no daughter vesicles, neither other abdominal organ involvement. This case is in line with the existing literature on laparoscopical treatment of splenic cystic hydatid disease, suggesting that laparoscopical treatment is a safe and effective approach for large splenic hydatid cysts to be preferred to open surgical techniques.

Proteomic analysis of the excretory/secretory products and antigenic proteins of Echinococcus granulosus adult worms from infected dogs

Background

Cystic echinococcosis, which is caused by Echinococcus granulosus, is one of the most widespread zoonotic helminth diseases that affects humans and livestock. Dogs, which harbor adult worms in their small intestines, are a pivotal source of E. granulosus infection in humans and domestic animals. Therefore, novel molecular approaches for the prevention and diagnosis of this parasite infection in dogs need to be developed.

Results

In this study, we performed proteomic analysis to identify excretory/secretory products (ES) and antigenic proteins of E. granulosus adult worms using two-dimensional electrophoresis, tandem matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF/TOF), and Western blotting of sera from infected dogs. This study identified 33 ES product spots corresponding to 9 different proteins and 21 antigenic protein spots corresponding to 13 different proteins. Six antigenic proteins were identified for the first time.

Conclusions

The present study extended the existing proteomic data of E. granulosus and provides further information regarding host-parasite interactions and survival mechanisms. The results of this study contribute to vaccination and immunodiagnoses for E. granulosus infections.

Neglected tropical diseases among the Association of Southeast Asian Nations (ASEAN): overview and update

The ten member states of the Association of Southeast Asian Nations (ASEAN) constitute an economic powerhouse, yet these countries also harbor a mostly hidden burden of poverty and neglected tropical diseases (NTDs). Almost 200 million people live in extreme poverty in ASEAN countries, mostly in the low or lower middle-income countries of Indonesia, the Philippines, Myanmar, Viet Nam, and Cambodia, and many of them are affected by at least one NTD. However, NTDs are prevalent even among upper middle-income ASEAN countries such as Malaysia and Thailand, especially among the indigenous populations. The three major intestinal helminth infections are the most common NTDs; each helminthiasis is associated with approximately 100 million infections in the region. In addition, more than 10 million people suffer from either liver or intestinal fluke infections, as well as schistosomiasis and lymphatic filariasis (LF). Intestinal protozoan infections are widespread, while leishmaniasis has emerged in Thailand, and zoonotic malaria (Plasmodium knowlesi infection) causes severe morbidity in Malaysia. Melioidosis has emerged as an important bacterial NTD, as have selected rickettsial infections, and leptospirosis. Leprosy, yaws, and trachoma are still endemic in focal areas. Almost 70 million cases of dengue fever occur annually in ASEAN countries, such that this arboviral infection is now one of the most common and economically important NTDs in the region. A number of other arboviral and zoonotic viral infections have also emerged, including Japanese encephalitis; tick-borne viral infections; Nipah virus, a zoonosis present in fruit bats; and enterovirus 71 infection. There are urgent needs to expand surveillance activities in ASEAN countries, as well as to ensure mass drug administration is provided to populations at risk for intestinal helminth and fluke infections, LF, trachoma, and yaws. An ASEAN Network for Drugs, Diagnostics, Vaccines, and Traditional Medicines Innovation provides a policy framework for the development of new control and elimination tools. Together with prominent research institutions and universities, the World Health Organization (WHO), and its regional offices, these organizations could implement important public health improvements through NTD control and elimination in the coming decade.

Molecular characterization of Echinococcus granulosus sensu lato from farm animals in Egypt

Little is known on the diversity and public health significance of Echinococcus species in livestock in Egypt. In this study, 37 individual hydatid cysts were collected from dromedary camels (n=28), sheep (n=7) and buffalos (n=2). DNA was extracted from protoscoleces/germinal layer of individual cysts and amplified by PCR targeting nuclear (actin II) and mitochondrial (COX1 and NAD1) genes. Direct sequencing of amplicons indicated the presence of Echinococcus canadenesis (G6 genotype) in 26 of 28 camel cysts, 3 of 7 sheep cysts and the 2 buffalo derived cysts. In contrast, Echinococcus granulosus sensu stricto (G1 genotype) was detected in one cyst from a camel and 4 of 7 cysts from sheep, whereas Echinococcus ortleppi (G5 genotype) was detected in one cyst from a camel. This is the first identification of E. ortleppi in Egypt.

Echinococcosis in wild carnivorous species: epidemiology, genotypic diversity, and implications for veterinary public health

Echinococcosis is a zoonosis caused by helminths of the genus Echinococcus. The infection, one of the 17 neglected tropical diseases listed by the World Health Organization, has a cosmopolitan distribution and can be transmitted through a variety of domestic, synanthropic, and sylvatic cycles. Wildlife has been increasingly regarded as a relevant source of infection to humans, as demonstrated by the fact that a significant proportion of human emerging infectious diseases have a wildlife origin. Based on available epidemiological and molecular evidence, of the nine Echinococcus species currently recognized as valid taxa, E. canadensis G8-G10, E. felidis, E. multilocularis, E. oligarthrus, E. shiquicus, and E. vogeli are primarily transmitted in the wild. E. canadensis G6-G7, E. equinus, E. granulosus s.s., and E. ortleppi are considered to be transmitted mainly through domestic cycles. We summarize here current knowledge on the global epidemiology, geographical distribution and genotype frequency of Echinococcus spp. in wild carnivorous species. Topics addressed include the significance of the wildlife/livestock/human interface, the sympatric occurrence of different Echinococcus species in a given epidemiological scenario, and the role of wildlife as natural reservoir of disease to human and domestic animal populations. We have also discussed the impact that human activity and intervention may cause in the transmission dynamics of echinococcosis, including the human population expansion an encroachment on shrinking natural habitats, the increasing urbanization of wildlife carnivorous species and the related establishment of synanthropic cycles of Echinococcus spp., the land use (e.g. deforestation and agricultural practices), and the unsupervised international trade and translocation of wildlife animals. Following the 'One Health' approach, we have also emphasized that successful veterinary public health interventions in the field of echinococcosis requires an holistic approach to integrate current knowledge on human medicine, veterinary medicine and environmental sciences.

Immunoblotting with human native antigen shows stage-related sensitivity in the serodiagnosis of hepatic cystic echinococcosis

The diagnosis of hepatic cystic echinococcosis is based on ultrasonography and confirmed by serology. However, no biological marker of cyst viability is currently available implying years-long patient follow-up, which is not always feasible in endemic areas. We characterized the performance of an immunoblotting test based on human hydatid cyst fluid with particular regard to its ability to distinguish between cyst stages. Sera from patients with cysts in different stages showed distinctive band pattern recognition. Most importantly, the test discriminated in 80% of cases CE3a from CE3b transitional cysts, known to have different viability profiles. Interestingly, we observed a rapid change in band pattern recognition of sera from one patient at time points when his cyst passed from active to transitional to inactive stages. Further identification of different antigens expressed by different cyst stages will support the development of diagnostic tools that could early define cyst viability, to guide clinical decision making, and shorten patient follow-up.

Canine echinococcosis: global epidemiology and genotypic diversity

Canine echinococcosis is a potential zoonotic infection caused by the adult form of several cestode species belonging to the genus Echinococcus, of which E. granulosus sensu lato and E. multilocularis are the most epidemiologically relevant. Dogs infected with E. granulosus and E. multilocularis are widely regarded as the main source of infection for human cystic and alveolar echinococcosis, diseases that cause substantial morbidity and socio-economic burden in several regions of the world. Following our previous review on the global situation of cystic echinococcosis in livestock species (Cardona and Carmena. Vet. Parasitol. 2013;192:10-32), we summarize here current knowledge on the global epidemiology, geographical distribution and molecular diversity of Echinococcus spp. infection in dogs. We address relevant topics including the implications of the increasing urbanization of wildlife species such as foxes, coyotes, and dingoes in the establishment of urban cycles of Echinococcus spp., or the rising concerns regarding the role of unsupervised translocation of infected dogs in spreading the infection to Echinococcus-free areas. The involvement of wildlife species as natural reservoirs of disease to domestic animals and humans and the epidemiological significance of the sympatric occurrence of different Echinococcus species in the same geographical region are also debated. Data presented are expected to be useful for policy makers, educational and health authorities responsible for designing and implementing effective measures for disease control and prevention.

Molecular identification of Echinococcus multilocularis infection in small mammals from Northeast, Iran

BACKGROUND

Alveolar echinococcosis is a zoonotic disease caused by the metacestode of Echinococcus multilocularis. Many species of small mammals, including arvicolid rodents or Ochotona spp., are natural intermediate hosts of the cestode. The main aim of this study was to identify natural intermediate hosts of E. multilocularis in Chenaran County, Razavi Khorasan Province, northeastern Iran, where the prevalence of infected wild and domestic carnivores is high.

METHODOLOGY/PRINCIPAL FINDINGS

A program of trapping was carried out in five villages in which this cestode was reported in carnivores. The livers of 85 small mammals were investigated for the presence of E. multilocularis infection using multiplex PCR of mitochondrial genes. Infections were identified in 30 specimens: 23 Microtus transcaspicus, three Ochotona rufescens, two Mus musculus, one Crocidura gmelini, and one Apodemus witherbyi.

CONCLUSIONS/SIGNIFICANCE

A range of small mammals therefore act as natural intermediate hosts for the transmission of E. multilocularis in Chenaran County, and the prevalence suggested that E. multilocularis infection is endemic in this region. The existence of the life cycle of this potentially lethal cestode in the vicinity of human habitats provides a significant risk of human infection.

Environmental changes impacting Echinococcus transmission: research to support predictive surveillance and control

Echinococcosis, resulting from infection with tapeworms Echinococcus granulosus and E. multilocularis, has a global distribution with 2-3 million people affected and 200,000 new cases diagnosed annually. Costs of treatment for humans and economic losses to the livestock industry have been estimated to exceed $2 billion. These figures are likely to be an underestimation given the challenges with its early detection and the lack of mandatory official reporting policies in most countries. Despite this global burden, echinococcosis remains a neglected zoonosis. The importance of environmental factors in influencing the transmission intensity and distribution of Echinococcus spp. is increasingly being recognized. With the advent of climate change and the influence of global population expansion, food insecurity and land-use changes, questions about the potential impact of changing temperature, rainfall patterns, increasing urbanization, deforestation, grassland degradation and overgrazing on zoonotic disease transmission are being raised. This study is the first to comprehensively review how climate change and anthropogenic environmental factors contribute to the transmission of echinococcosis mediated by changes in animal population dynamics, spatial overlap of competent hosts and the creation of improved conditions for egg survival. We advocate rigorous scientific research to establish the causal link between specific environmental variables and echinococcosis in humans and the incorporation of environmental, animal and human data collection within a sentinel site surveillance network that will complement satellite remote-sensing information. Identifying the environmental determinants of transmission risk to humans will be vital for the design of more accurate predictive models to guide cost-effective pre-emptive public health action against echinococcosis.

Human alveolar echinococcosis in Poland: 1990-2011

Background

Alveolar echinococcosis (AE) caused by Echinococcus multilocularis infections is a dangerous old disease in the Northern Hemisphere. The aim of the paper was to collect and analyze data on human AE in Poland in the last two decades.

Methodology/Principal Findings

The sources of data were both the cases officially registered and detected by an active field and laboratory surveillance. The cases were verified by clinical, epidemiological, and laboratory criteria. Altogether 121 human cases of AE were detected. Among these 83 (68,6%) cases were classified as confirmed, 16 as probable and 22 as possible. During the two decades a continuous increase in detection rate was noticed. The cases were 6–82 years old at the time of diagnosis (mean - 47.7 years). Sex ratio M/F was 0.86/1.0. The AE was fatal in 23 (19%) patients (mean age at death - 54.1 years). Family agglomeration of AE was found in 4 foci, involving 9 patients. Seventy six of the cases were diagnosed in an advanced stage of disease. In all cases the liver was the primary location of AE. In 30 (24.8%) patients a spread to other organs was observed. Ninety four of the patients were treated with albendazole. In 73 (60%) patients a surgical operation was performed, including 15 liver transplantations.

Conclusions/Significance

The studies confirmed that AE is an emerging disease in Poland, which is the fourth country in Europe with over 120 cases detected. The results also indicate the need of a wider national programme for implementation of screening in the highest AE risk areas (north-eastern Poland) with an effort to increase the public awareness of the possibility of contracting E. multilocularis, and above all, training of the primary care physicians in the recognition of the risk of AE to allow for an early detection of this dangerous disease.

Human alveolar echinococcosis (AE) is a consequence of accidental ingestion of the eggs of the tapeworm Echinococcus multilocularis. AE constitutes a serious and increasing medical and epidemiological problem in many countries including Poland. The natural environments with a high AE prevalence are the areas where the definitive hosts (foxes, raccoons) and the intermediate hosts (rodents) live. The increasing population of infected foxes that penetrate nearby the village and urban buildings and infected dogs poses a certain risk to human health. This report is a joint clinical and epidemiological analysis of 121 AE cases recorded in the years 1990–2011 in Poland. The highest percentage of E. multilocularis infected foxes in the north-eastern regions of Poland (about 40% of the examined population infected) bears a clear-cut relation to the highest incidence of detected AE human cases in those areas. An epidemiological and clinical survey of the local population conducted for over a dozen years has contributed to the discovery of several new AE cases. Alveolar echinococcosis in humans caused by Echinococcus multilocularis infection belongs to the emerging diseases in Poland where a continuous increase in the detection rate was noticed during the last two decades.

A cross-sectional study of Taenia solium in a multiple taeniid-endemic region reveals competition may be protective

We conducted cross-sectional surveys for taeniasis and cysticercosis in humans, pigs, and dogs in four northern provinces of Laos. Human cysticercosis and taeniasis prevalence was 2.2% (95% confidence interval [CI] = 1.4-3.0%) and 8.4% (95% CI = 6.9-9.9%), respectively. Eating uncooked beef, being male, province of residence, age, and ethnicity were significant risk factors for taeniasis and only province of residence was a significant risk factor for cystiercosis. Thirty-five human tapeworms were recovered during the survey and 33 (94.3%) and 2 (5.7%) were identified as Taenia saginata and T. solium, respectively. Maximum-likelihood adjusted prevalence of T. solium and T. hydatigena in pigs was 4.2% (95% CI = 0.5-7.9%) and 55.9% (95% CI = 47.5-64.3%), respectively, and T. hydatigena taeniasis in dogs was 4.8% (95% CI = 0.0-11.3%). Taenia hydatigena and T. saginata were the most prevalent taeniids in the respective pig and human populations and together may suppress T. solium transmission.

Challenges for diagnosis and control of cystic hydatid disease

This paper is based on the experience of the authors, with the aim to define the challenges for Echinococcus granulosus (E.g./CE) diagnosis and control for those countries that may now or in the future be contemplating control of hydatid disease. A variety of methods are available for diagnosis in humans but a universal gold standard is lacking. Diagnosis in definitive hosts can avoid necropsy by the use of methods such as coproantigen detection but test performance is variable between populations. A sylvatic cycle adds challenges in some countries and the epidemiology of the parasite in these hosts is poorly understood. Control by solely administering praziquantel to dogs is not effective in developing countries where the disease is endemic. Additional avenues to pursue include the instigation of participatory planning, use of an existing vaccination for intermediate hosts and development of a vaccine and long-acting anthelmitic implants for definitive hosts. Promoting public acceptance of control of the dog population by humane euthanasia and reduced reproduction is also essential.

Serological diagnosis of lung cystic hydatid disease using the synthetic p176 peptide

Cystic hydatid disease (CHD) is a worldwide zoonosis caused by the larval stage of the dog tapeworm Echinococcus granulosus. Diagnosis is based on imagenological tools (abdominal ultrasound, chest X-rays, or computed tomography [CT] scan). Serological antibody-detecting assays, using diverse native antigens, have been used as a supportive diagnostic tool, but their sensitivities and specificities differ greatly. The use of synthetic peptides as antigens should provide more reliability and allow better assessment and comparison of test formats and case series. The synthetic peptide p176, corresponding to the N-terminal extreme of the subunit of antigen B (AgB8/1), has shown promising performances for diagnosis of CHD. We evaluated the performance of the synthetic peptide p176 for the diagnosis of pulmonary hydatid disease in an enzyme-linked immunosorbent assay (ELISA) format. Sixty-one serum samples from patients with a diagnosis of pulmonary hydatidosis confirmed by surgery and 128 from healthy volunteers were tested. The overall sensitivity and specificity of the p176 ELISA for lung CHD were 78.69% and 96.88%, respectively. On bivariate analysis, positive serum antibody reactions were associated with the presence of complications and with the number of cysts (single/multiple). Only the presence of persistent complications significantly associated with seropositivity on multivariate logistic regression analysis (odds ratio [OR], 9.58; 95% confidence interval [CI], 2.15 to 42.6; P = 0.003). The p176 ELISA performs well for the diagnosis of lung CHD and adds an easily reproducible diagnostic assay to the existing diagnostic tools.

Human and canine echinococcosis infection in informal, unlicensed abattoirs in Lima, Peru

Echinococcus granulosus infections are a major public health problem in livestock-raising regions around the world. The life cycle of this tapeworm is sustained between dogs (definitive host, canine echinococcosis), and herbivores (intermediary host, cystic hydatid disease). Humans may also develop cystic hydatid disease. Echinococcosis is endemic in rural areas of Peru; nevertheless, its presence or the extension of the problem in urban areas is basically unknown. Migration into Lima, an 8-million habitant's metropolis, creates peripheral areas where animals brought from endemic areas are slaughtered without veterinary supervision. We identified eight informal, unlicensed abattoirs in a peripheral district of Lima and performed a cross-sectional study in to assess the prevalence of canine echinococcosis, evaluated by coproELISA followed by PCR evaluation and arecoline purge. Eight of 22 dogs (36%) were positive to coproELISA, and four (18%) were confirmed to be infected with E. granulosus tapeworms either by PCR or direct observation (purge). Later evaluation of the human population living in these abattoirs using abdominal ultrasound, chest X-rays and serology, found 3 out of 32 (9.3%) subjects with echinococcal cysts in the liver (two viable, one calcified), one of whom had also lung involvement and a strongly positive antibody response. Autochthonous transmission of E. granulosus is present in Lima. Informal, unlicensed abattoirs may be sources of infection to neighbouring people in this urban environment.

Echinococcus granulosus infections are a major public health problem in livestock-raising regions around the world. This parasite is transmitted by dogs, and humans could be accidentally infected, developing cystic lesions in internal organs after several years of infection. The risk of infection has been widely described in Peruvian rural areas; nevertheless the extension of the problem in urban areas is basically unknown. Migration into Lima, an 8-million habitant's metropolis, creates peripheral areas where animals brought from endemic areas are slaughtered without veterinary supervision. In our study, we assess the number of infected dogs, which were living in eight informal, unlicensed abattoirs in a peripheral district of Lima, by evaluation of dog faeces using different techniques. We identified that 4 of 22 dogs were infected with E. granulosus worm. Later evaluation of the human population living in these abattoirs using abdominal ultrasound, chest X-rays and serology, found 3 of 32 subjects had echinococcal cysts in the liver, one of whom had also a cyst in lung and a positive serological test. This work demonstrates that autochthonous transmission of E. granulosus is present in Lima and that informal, unlicensed abattoirs may be sources of infection to neighbouring people in this urban environment.

Echinococcus multilocularis: molecular characterization of EmSmadE, a novel BR-Smad involved in TGF-β and BMP signaling

Smad transcription factors are central components of transforming growth factor-β (TGF-β)/bone morphogenetic protein (BMP) signaling pathways in metazoans, and regulate key developmental processes such as body axis formation or regeneration. In the present study, we have identified and characterized a novel member of this protein family, EmSmadE, in the human parasitic cestode Echinococcus multilocularis, the causative agent of alveolar echinococcosis. The cDNA of the corresponding gene, emsmadE, was fully sequenced and shown to encode a protein with considerable homologies to known members of the receptor regulated Smad (R-Smad) family of a wide variety of organisms. EmSmadE contains highly conserved MH1- and MH2-domains and, on the basis of sequence features around the L3 loop region, could be assigned to the BR-Smad subfamily that typically transmits BMP signals. RT-PCR analyses indicated expression of emsmadE in all larval stages that are involved in the infection of the intermediate host. Yeast two-hybrid interaction studies demonstrated that EmSmadE can form homodimers, and is capable of heterodimer formation with the previously identified common Smad (Co-Smad) EmSmadD and the R-Smads, EmSmadA, and EmSmadB. In a heterologous expression system, EmSmadE was specifically phosphorylated at a conserved C-terminal SSVS motif by the human BMP type I receptor and, despite being structurally a BR-Smad, also by the human TGF-β type I receptor. Taken together, these data indicate that EmSmadE is a functionally active R-Smad that is involved in larval Echinococcus development. The data presented herein will be important for further analyses on the role of TGF-β/BMP signaling pathways in Echinococcus pattern formation and differentiation.

Proteomic characterisation of Echinococcus granulosus hydatid cyst fluid from sheep, cattle and humans

The hydatid cyst fluid (HCF) of Echinococcus granulosus is a complex biological mixture containing a wide range of proteins of both parasite and host origin. Using a combination of in- and off-gel protein fractionation techniques and tandem mass spectrometry 130 HCF proteins were identified from fertile cysts of sheep and human origin and infertile cysts from cattle. Forty-eight proteins were of parasite origin including Antigen 5 and Antigen B--the most abundant parasite proteins, thioredoxin, low-density lipoprotein receptors, cyclophilin and ferritin. Across the three host species the identified HCF proteins were broadly similar although, based on spectral counts, three proteins, including an antigen B isoform, were more abundant in sheep HCF compared with the fluids of cattle and human origin. Eighty-two host proteins were identified in HCF from the three species. Host plasma proteins were the most abundant, although approximately thirty of the host proteins that were identified are not considered constituents of plasma. The identification of parasite heat shock proteins and annexin A13 exclusively in infertile cysts, along with an increased spectral count for cathepsin B, supports the hypothesis of increased cellular stress and apoptosis as the cause of their infertility.

Control of important helminthic infections vaccine development as part of the solution

Among the tools available for the control of helminth infections, chemotherapy has come to totally dominate the field. In the veterinary field, development of drug resistance has appeared but this is not (yet) a problem in the control of human diseases. Although there is no vaccine commercially available for any human parasitic infection yet, recent progress in vaccine development is making this a future possibility for several diseases. The goal of chemotherapy is to alleviate infection and morbidity in the definitive host, or reduce transmission, while the effect of available vaccine candidates would mainly be to influence transmission through targeting the intermediate or reservoir host, when the infection is zoonotic. Apart from this general scheme, there are also vaccine candidates targeting the parasites in the definitive host, in particular the early developmental stages, which should reduce the risk of drug failure. Since the biological targets in most cases are different, vaccination would be synergistic with drug therapy. This review covers diseases caused by helminthes in both humans and animals and includes examples of diseases caused by cestodes, nematodes and trematodes. The focus is on infections for which vaccine development has been undertaken for a long time, resulting in products that could realistically become integrated into control strategies in the near future.

Health metrics for helminthic infections

Over the past five decades, accurate and comparable assessment of disease burden due to different 'worm' infections has proven problematic. Estimates of the health impact of helminths have varied significantly, depending on the assessor's perspective and the approaches taken to quantifying disease effects on patient performance status. Past surveys have frequently suffered from misclassification bias due to the lack of a diagnostic 'gold' standard. At the same time, there has been a tendency to define disease based solely on late-onset, 'pathognomonic' outcomes that can be uniquely attributed to each pathogen. However, we are now gaining a much better understanding of the role of helminths in anaemia causation, impaired growth and development, and poor school or work performance. With a new appreciation of the link between long-term, parasite-mediated inflammation and the patient's lifetime risk of disability, we recognise that the bulk of worm-associated diseases is found in the latter, 'non-specific' categories, with relevance to individual performance status and detriment to regional levels of human capital. Appropriately, the emerging use of comprehensive disability metrics such as the quality-adjusted life year (QALY)-as opposed to the widely used disability-adjusted life year (DALY) metrics-will better capture the impact of helminthic infections on the long-term health of Asian and other developing world populations. This improved, more valid assessment is expected to provide evidence favouring preventive over curative intervention for control of these highly prevalent diseases.