Coproantigens in taeniasis and echinococcosis

Wildlife parasitology: sample collection and processing, diagnostic constraints, and methodological challenges in terrestrial carnivores

Wild terrestrial carnivores play a crucial role as reservoir, maintenance, and spillover hosts for a wide parasite variety. They may harbor, shed, and transmit zoonotic parasites and parasites of veterinary importance for domestic hosts. Although wild carnivores are globally distributed and comprise many different species, some living in close proximity to human settlements, only a few studies have investigated parasites of wild terrestrial carnivores using non-specific techniques. Access to samples of wild carnivores may be challenging as some species are protected, and others are secretive, possibly explaining the data paucity. Considering the importance of wild carnivores' health and ecological role, combined with the lack of specific diagnostic methodologies, this review aims to offer an overview of the diagnostic methods for parasite investigation in wild terrestrial carnivores, providing the precise techniques for collection and analysis of fecal, blood, and tissue samples, the environmental impact on said samples, and the limitations researchers currently face in analyzing samples of wild terrestrial carnivores. In addition, this paper offers some crucial information on how different environmental factors affect parasite detection postmortem and how insects can be used to estimate the time of death with a specific highlight on insect larvae. The paper contains a literature review of available procedures and emphasizes the need for diagnostic method standardization in wild terrestrial carnivores.

Epidemiology of Echinococcus granulosus sensu lato in the Greater Horn of Africa: A systematic review

BACKGROUND

Cystic echinococcosis (CE) is a neglected zoonotic disease that is caused by Echinococcus granulosus sensu lato (s.l.), the life cycle of which involves multiple hosts. We conducted a systematic review (SR) on E. granulosus s.l. in the Greater Horn of Africa (GHA), to provide a picture of its recent epidemiology across all hosts.

METHODS

For this SR, conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, five electronic databases, as well experts in the region were consulted to retrieve records published between 2000 and 2022, reporting the presence of E. granulosus s.l. infections in any natural host in the GHA (Djibouti, Eritrea, Ethiopia, Kenya, Sudan, Somalia, South Sudan, Tanzania and Uganda).

PRINCIPAL FINDINGS

A total of 247 records were retained, describing the presence of E. granulosus s.l. throughout the GHA, except for Djibouti. Only few population surveys on human CE were conducted in the area, with the prevalence ranging between 0.3 and 11.3%. In animals, the reported prevalence ranged up to 61.6% in camels, 88.4% in cattle; 65.2% in goats, 9.9% in pigs, 67.8% in sheep and 94.5% in dogs. In addition, E. granulosus s.l. was also reported in wildlife. A total of five species were reported in the different hosts, namely E. granulosus sensu stricto (G1, G3, GOmo), E. canadensis (G6/7), E. ortleppi (G5), E. felidis, and E. equinus (G4).

CONCLUSIONS

We confirm that E. granulosus s.l. is prevalent throughout the GHA. Nevertheless, despite our efforts to screen grey literature, an accurate assessment of the epidemiology in GHA remains challenging, due to the lack of combined host, in-depth risk factor and behavioural studies, as well as the wide diversity in subpopulations studied and diagnostic tools used. Interdisciplinary and transboundary partnerships would be essential for the design of effective control strategies, tuned to the GHA setting.

Development and Laboratory Evaluation of a Simple, Field-Applicable Coproantigen Enzyme-Linked Immunosorbent Assay for Diagnosis of Taeniasis in Northern Peru

Coproantigen detection by enzyme-linked immunosorbent assay (coAg ELISA) is a vital tool for detecting and treating cases of Taenia solium taeniasis. However, the assay's procedures require costly materials and sophisticated equipment, which are typically inaccessible in rural settings where the disease is endemic. To overcome these barriers, we developed and evaluated a field-applicable coAg ELISA. The field coAg ELISA was developed and evaluated across four phases using known positive and negative stool samples collected from northern Peru. Phase I focused on field assay development, phase II on a small-scale performance evaluation, phase III on a large-scale evaluation, and phase IV on the use and reliability of a colorimetric scale card. All samples were processed using the field and standard assay procedures and compared using signal-to-noise ratios, correlation tests, performance characteristics, and agreement statistics where appropriate. The field coAg ELISA using reagents stored at -20°C and commercially available water and milk powder, and relying on spontaneous separation of the supernatant, had performance comparable to the standard assay. The field coAg ELISA was strongly correlated with the standard in both the small- and large-scale laboratory evaluation (r = 0.99 and r = 0.98, respectively). Finally, the field assay had an almost perfect agreement between independent readers (kappa = 0.975) and between each reader and the spectrophotometer. The field coAg ELISA demonstrated performance comparable to the standard, providing a low-cost alternative to the standard assay for identifying cases of intestinal taeniasis in a low-resource setting.

The potential role of roaming dogs in establishing a geographically novel life cycle of taeniids (Echinococcus spp. and Taenia spp.) in a non-endemic area

INTRODUCTION

Cystic Echinococcosis (CE) is endemic in humans and livestock in many pastoral communities in Kenya. The distribution of the disease is enhanced by several factors, including livestock trade, which has allowed for the spread of CE to non-endemic areas such as western Kenya. Dogs' roaming behaviour, with consequent contamination of the environment with intestinal parasites, could then lead to parasite establishment. This study examined dogs' infection levels with taeniid eggs and their potential role in contaminating the environment with intestinal parasites.

METHODOLOGY

We selected sixteen ruminant slaughterhouses in Busia and Bungoma Counties, and around each slaughterhouse we identified ten homesteads owning free-roaming dogs. We administered a questionnaire on dog management practices to the homestead owner and collected a faecal sample from the dog's rectum. In homesteads around 8 of the 16 slaughterhouses, we collared dogs with a GPS tracker to assess their movement patterns. The faecal samples were examined microscopically following zinc-chloride sieving-floatation technique for the presence of taeniid eggs and other canine intestinal parasites. Polymerase Chain Reaction - Restriction Fragment Length Polymorphism of NADH dehydrogenase subunit 1 gene and sequencing were used to confirm taeniid eggs identified during microscopy. Additionally, the Coproantigen-ELISA was used to detect the presence of taeniid antigen in a sub-set of the faecal samples.

RESULTS

Helminths detected in the 155 dogs sampled included hookworms (n = 92; 59.4%), ascarids (n = 15; 9.7%), and taeniids (n = 1; 0.6%). Through Copro-PCR, 13 eggs extracted from the sample of the only taeniid infected dog were sequenced and identified as E. canadensis (G6/7) [n = 1], Taenia multiceps [n = 1], and Taenia serialis [n = 6]; the remaining were indeterminate. Of the 77 faecal samples tested for E. granulosus sensu lato (s. l.) with the Copro-ELISA, 64 (83.1%) were negative, 12 (15.6%) were positive, while 1 (1.3%) was suspicious. The dogs travelled a median of 13.5 km daily, and 28 dogs visited the slaughterhouses during the 5-day recording period.

CONCLUSION

The results indicate a relatively high carriage of zoonotic parasites by free-roaming domestic dogs in western Kenya, which poses a risk to human and livestock populations. We report for the first time a domestic lifecycle of Echinococcus canadensis and Taenia multiceps in western Kenya, as well as a presumptive sylvatic cycle of coenurosis by T. serialis. We recommend an extensive and ongoing Copro-antigen survey of dog faeces, broader assessment of dog parasites with zoonotic potential, adherence to slaughterhouse management practices, and dog-ownership programmes to highlight the importance of deworming and restricted dog movements.

Challenges in the Diagnosis of Taenia solium Cysticercosis and Taeniosis in Medical and Veterinary Settings in Selected Regions of Tanzania: A Cross-Sectional Study

Background

Taenia solium (neuro) cysticercosis/taeniosis (TSCT) is a zoonotic disease complex. There is a perceived inefficient diagnosis of infections by either form, the adult pork tapeworm (taeniosis) and the larval stage of it (cysticercosis), in low-income settings, including Tanzania. This study aimed at identifying potential gaps around TSCT diagnosis and knowledge of primary healthcare providers (officers in charge (OICs) of primary healthcare facilities (PHFs)) and veterinarians (meat inspectors (MIs)) on various aspects of TSCT disease complex and addressing effective disease control in Tanzania. Methodology. A cross-sectional study was conducted between January and April 2020 in Manyara, Dodoma, Ruvuma, Iringa, and Arusha regions in Babati, Mbulu, Kongwa, Mbinga, and Nyasa districts. We interviewed 152 OICs of PHFs and 108 MIs using a structured questionnaire and 33 medical and veterinary officers from level I healthcare facilities and district livestock offices, respectively, from selected study districts to the respective ministerial level using key informant interviews.

Results

Quantitative data revealed inadequate microscopic diagnostic facilities (54.6%) and personnel (100%) for taeniosis diagnosis in PHFs (n = 152). Approximately 81.2% of MIs compared with only 42.1% of OICs of PHFs scored above average regarding T. solium cysticerci knowledge. Nevertheless, 61.2% of OICs of PHFs compared with only 42.6% of MIs scored above average regarding the adult T. solium tapeworm knowledge. Qualitative data revealed inadequate availability of advanced diagnostic facilities (neuroimaging) and trained personnel for specific diagnosis of TSCT with a focus on neurocysticercosis (NCC) in secondary and tertiary healthcare facilities. Inadequately number of qualified MIs, slaughter slabs, and resource facilitation challenged porcine cysticercosis diagnosis.

Conclusion

It is concluded that diagnostic capacity and knowledge of OICs of PHFs and MIs regarding TSCT are insufficient in both medical and veterinary sectors. A One Health approach should be adopted to improve TSCT diagnostic capacity and practitioners' knowledge in both medical and veterinary sectors.

CD3/TCRE Expression and Immunoregulatory Milieu Induced in a Secondary Intermediate Host by Different Phases of Hydatid Cyst

BACKGROUND

Echinococcosis is a common health problem in the Mediterranean and the Middle East, and manifests without any symptoms, even in the advanced stages.

OBJECTIVE

The present study aimed to investigate the cell mediated-immunoregulatory milieu in rats' echinococcosis induced by three different viability status of Echinococcus granulosus especially in the semi-calcareous stage, which can be used as novel biomarkers to monitor disease progression and open the door to a deeper understanding of the pathways that could contribute to complementary echinococcosis therapies.

MATERIALS AND METHODS

Rat infection with echinococcosis was induced by three different viable statuses of Echinococcus granulosus (G6) camel strain. During the different stages of parasitic infection, blood serum was harvested from rats containing low-, high-, and not viable (not completely transformed to the calcareous status) protoscoleces fluid. The host Th1/Th2 cytokines-mediated immune cell activation, as well as CD3/TCRE immunoregulation, and proliferation responses were investigated; especially in the semi-calcareous stage as this is the first report characterizing this stage.

RESULTS

Both IFN-γ and IL-6 levels significantly increased in the infected groups (P < 0.05), in addition, increased positive immunoreactions in splenic tissue for both CD3/TCRE and Ki-67 monoclonal antibodies.

CONCLUSION

E. granuloses infection-induced immune tolerance is involved in disease progression, and modulates the activation and regulation of host immune response, even in the early stages of infection, rather than the last stages of viability (semi-calcareous) is not neglected stage. This study is the first to report that the semi-calcareous stage causes a severe immunological response.

Challenges Encountered When Evaluating an Antibody-Detecting Point-of-Care Test for Taeniosis in an Endemic Community in Zambia: A Prospective Diagnostic Accuracy Study

Taenia solium taeniosis diagnosis is challenging because current tests perform sub-optimally and/or are expensive, require sophisticated equipment, infrastructure and trained manpower, and therefore are not community deployable. A recently-developed, multi-strip, T. solium point-of-care test (TS POC) for simultaneous detection of tapeworm (TS POC T) and cysticercus (TS POC CC) human antibodies was evaluated for diagnostic accuracy on consecutively recruited community participants in Sinda district, Zambia. All participants were tested using the TS POC test. All test-positives and 20% of the test-negative participants were invited to give a blood and stool sample for reference testing. Three different reference tests were used for taeniosis diagnosis: recombinant rES33 enzyme-linked immunoelectrotransfer blot (rES33 EITB), copro PCR and copro Ag ELISA. Bayesian analysis with probabilistic constraints was used to estimate sensitivity and specificity. In total, 1254 participants were tested with the TS POC test, of whom 13 tested positive using the TS POC T. Based on 161 participants with complete data, the estimated sensitivity and specificity for the TS POC T test were 38% (95% CI: 5–93%) and 99% (95% CI: 98–100%), respectively. The challenge of highly variable inter-assay performance is highlighted. We recommend either increasing the sensitivity or redesigning the test.

Copro-polymerase chain reaction has higher sensitivity compared to centrifugal fecal flotation in the diagnosis of taeniid cestodes, especially Echinococcus spp, in canids

Prompt and reliable diagnostic tests for taeniid infection in canids are important due to the risk of zoonoses like Echinococcus spp. Current diagnostic methods relying on fecal flotation lack sensitivity and specificity, but this has rarely been quantified due to the challenges in performing adult cestode recovery (the gold standard) in domestic dogs (Canis familiaris). Therefore, we recovered adult Taenia and Echinococcus spp. from intestines, as well as fecal/intestinal material from 484 wild canids trapped for fur in two Canadian provinces (276 foxes - primarily Vulpes vulpes, coyotes - Canis latrans, and wolves - Canis lupus in Québec and 208 coyotes in Saskatchewan). The performances of a newly developed coproPCR for tapeworm DNA detection in dogs, and centrifugal fecal flotation using Sheather's solution, were evaluated against adult cestode recovery. Overall, adult taeniid cestode prevalence (Taenia and/or Echinococcus) was 28 % (95 % CI: 23-33 %) in Québec (62 % (CI: 51-73%) of 74 coyotes, 65 % (CI: 44-82) of 23 wolves, and 11 % (CI: 7-16%) of 179 foxes) and 79 % (CI: 73-84%) of 208 coyotes in Saskatchewan. In Québec, E. canadensis and Taenia spp. were detected in coyotes and wolves, and foxes were only infected with Taenia spp., whereas Saskatchewan coyotes were predominantly infected with E. multilocularis (at significantly higher prevalence, but not intensity, than coyotes in Québec). Compared with centrifugal fecal flotation, the new coproPCR had at least double the sensitivity (58 % vs 23 % in QC coyotes, 57 % vs 23 % in QC wolves, 24 % vs 0% in QC foxes, and 80 % vs 25 % in SK coyotes). Notably, no taeniid eggs were detected on flotations from foxes infected with Taenia spp., and the new coproPCR had highest sensitivity in Saskatchewan coyotes, which were predominantly infected with E. multilocularis. CoproPCR has promising prospects for use in Veterinary clinics and diagnostic laboratories to detect taeniid cestode infections because of its higher sensitivity than faecal flotation methods. This is particularly important for zoonotic Echinococcus spp. where, from a public health perspective, false negatives are a much greater concern than false positives.

Echinococcosis in humans and animals in Southern Africa Development Community countries: A systematic review

The taeniid Echinococcus is the causative agent of the zoonotic disease echinococcosis/hydatidosis and is associated with economic losses in livestock production. This review summarizes available scientific literature on circulating species of Echinococcus in humans, wild and domestic animals in countries of Southern Africa Development Community, and identifies knowledge gaps and recommend research priorities. Data were systematically accessed from Google Scholar, MEDLINE/PubMed and from library resources from December 2017 to June 2019. Meta-analysis was conducted in STATA program and heterogeneity and prevalence values were pooled by host species with 95% confidence interval. In intermediate hosts, the overall prevalence of Echinococcus by meat inspection was 10% (CI: 9-11%) in small ruminants, 7% (CI: 5-8%) in cattle, 1% (CI: 0-1%) in pigs and 9% (CI: 0-29%) in wild herbivores. In canids by CoproAg-ELISA and necropsy the prevalence was of 10% (CI: 8-10%) and 6% (CI: 3-10%) respectively. A high level of heterogeneity (I2 > 65%) was observed for all study groups. Echinococcus equinus, E. canadensis, E ortleppi and E. felidis were reported from wildlife and E. ortleppi, E. granulosus s. s. and E. canadensis from humans. There is paucity of research in echinococcosis and gaps in prevalence reports over time in both humans and animals in the SADC region and we recommend an increase in future studies on the epidemiology of disease, risk factors for transmission in animals and humans and its relation with human health specially in the advent of HIV pandemic following a "One Health" approach.

Diagnosis of Taeniosis in rural Venezuelan communities: Preliminary characterization of a Taenia solium specific monoclonal (VP-1) Coproantigen ELISA

The objective of this study was to identify and treat carriers of adult Taenia solium present in two rural Venezuelan communities through examination of faecal samples by coproscopical analysis, and by the application of a polyclonal and a monoclonal (VP-1) coproantigen ELISA. Both the polyclonal and monoclonal ELISA's were negative when tested with soluble extracts of adults of Ascaris lumbricoides, Hymenolepis nana and Trichuris trichura. The polyclonal ELISA was positive for soluble extracts adults of T. solium and T. saginata, whereas the monoclonal ELISA, which recognizes a glycoprotein, was restricted to T. solium, and was also negative with faecal samples from five cases of T. saginata adult infections. In the first community studied, Potrero Largo (Total population: 300), of 248 faecal samples examined, 2 individuals were positive for Taenia spp eggs by coproscopical analysis and the VP-1 ELISA, and yielded T. solium adults upon purging. In contrast, when the polyclonal coproAg ELISA was applied to the same 248 faecal samples, there were a considerable number of positives. Indeed, seven patients highly positive in the polyclonal ELISA did not yield a Taenia spp upon purging and were negative in the VP-1 ELISA. In the second community studied La Yuca (Total population 560), none of the 333 individuals who donated faeces was positive for Taenia spp eggs. Many, however, were infected with a range of intestinal helminth and protozoan parasites. A total of 76 faecal samples with representative intestinal parasite were then tested in the polyclonal and VP-1 assays. Of these, many gave an unacceptable number of significant optical densities in the polyclonal coproAg ELISA. In contrast, all were negative in the VP-1 ELISA, thus providing evidence for the species specificity of the VP-1 ELISA in faecal samples. These results with the VP-1 coproAg ELISA, although preliminary, justify further validation through the testing of more faecal samples from T. solium and T. saginata adult infected individuals.

Identification of potential 'hot spots' of cystic echinococcosis transmission in the province of Río Negro, Argentina

Cystic echinococcosis (CE) is a parasitic zoonosis caused by Echinococcus granulosus. The control program of CE of Rio Negro province, Argentina, involves annual surveillance using ultrasound (US) screening in school children, and five-year cross-sectional surveys to detect livestock farms with parasitized dogs by coproELISA with confirmation tests (Western Blot or PCR). Control program is based on deworming of dogs with praziquantel and the aim is to identify areas at risk of Cystic echinococcosis transmission to humans, using all available data sources. The information was spatially distributed in 13 program areas and, at a smaller geographical scale, in 80 Primary Health Care Centers. CoproELISA surveys involved three randomized sampling periods (2003-05, 2009-10, 2017-18), with 1790 canine fecal samples. The US surveys were conducted in 2003-08, 2009-16 and 2017-18 in 34,515 children. Heat maps were created at the smallest geographic scale with QGIS 3.4.6. For the consecutive sampling periods, prevalence of positive canine fecal samples from livestock farms were 14.7, 12.1 and 7.8%, respectively, and children prevalence was 0.4, 0.2 and 0.1%, respectively. The study has been developed on a scale according to which the temporal-spatial distribution of CE allows to adjust control strategies in those areas of potential transmission of the zoonosis to humans.

Cysticercosis, a Potential Public Health Concern in Kuwait: A New Diagnostic Method to Screen Taenia solium Taeniasis Carriers in the Expatriate Population

OBJECTIVE

Taenia solium infection is not endemic to Kuwait, butseveral casesof cysticercosis have been detected in Kuwaiti nationals with no history of travelling to endemic countries. Infected domestic helpers/food handlers from endemic countries who may have escaped detection of infection by microscopy at the time of their arrival in Kuwait have been suspected as the possible source of infection. This study determined the seroprevalence of T. solium among domestic helpers/food handlers by screening their blood using a sensitive taeniasis-specific anti-rES33 antibody assay.

SUBJECTS AND METHODS

Newly arrived domestic helpers (n = 500) and food handlers (n = 500) from endemic countries were enrolled in the period 2015-2017. T. solium-specific rES33 antigen was expressed and purified from human embryonic kidney (HEK)293-6E cells using the pTT5 mammalian expression vector. Stool samples were processed for microscopy, and blood samples were screened to detect anti-T. soliumtaeniasis-specific IgG antibodies by ELISA.

RESULTS

All stool samples were negative for T. soliumparasiteeggs by microscopy. However, 42 individuals (4.2%) tested positive for T. soliumtaeniasis-specific IgG antibodies. Though statistically not significant, the IgG seropositivity was higher in individuals with a lower education level, a low-income background, and a lower frequency of hand-washing.

CONCLUSIONS

This is the first report from Kuwait and the Middle East on the detection of anti-T. soliumtaeniasis-specific serum IgG antibodies among the high-risk expatriate population. The results emphasize the importance of efficient and sensitive screening of T. solium carriers and thus the prevention of infection transmission and development of cysticercosis in the local population.

Development and Validation of a Copro-Enzyme-Linked Immunosorbent Assay Sandwich for Detection of Echinococcus granulosus-Soluble Membrane Antigens in Dogs

Cystic echinococcosis (CE) is a parasitic zoonosis caused by the larval stage of the tapeworm Echinococcus granulosus. Detection of the adult stage in the canine definitive host is essential for estimating infection rates, surveillance and monitoring of CE control programs. This study sought to develop and validate a coproantigen sandwich enzyme-linked immunosorbent assay (copro-ELISA), based on antibodies against E. granulosus-soluble membrane antigens (EGMA), that is capable of distinguishing infected and noninfected dogs. Anti-E. granulosus polyclonal immunoglobulin G antibodies were obtained from rabbit antiserum against EGMA. Optimization of the test was performed with 51 positive and 56 negative stool samples of canine echinococcosis. Specificity, sensitivity, cross-reactivity, intra- and inter-assay precision, and over time detection were evaluated. According to the receiver operating characteristic analysis, the diagnostic sensitivity and specificity were 96.1% (CI: 85.9-99.6) and 98.2% (CI: 89.5-100), respectively. Negative and positive predictive values were 96.5% (CI: 91.7-100) and 98% (CI: 94.1-100), respectively. No cross-reactivity with Taenia hydatigena, Dipylidium caninum, or Toxocara canis was observed. Intra- and inter-assay repeatability showed values of less than 15% of the variation coefficient. The over time detection was from 20 to 27 days postinfection with E. granulosus. The copro-ELISA based on EGMA detection offers a simplified in-house development of diagnostic testing. This assay showed high specificity and sensitivity and had no cross-reactivity with other parasites. Further studies and development of this test in a kit format may be useful for the detection of active infection in dogs living in CE endemic regions.

Historical perspective: The British contribution to the understanding of neurocysticercosis

Neurocysticercosis, or brain infestation with the larval stage of Taenia solium, is the most common risk factor for epilepsy in many endemic regions of the world. Hardly any cases are seen in Western developed countries, including Britain. However, a sizeable number (n = 450) was seen among British soldiers returning from deputation to India, then a British colony, first reported by Col. MacArthur at the Queen Alexandria Military Hospital in 1931. Here, we review the influence of the perceptive observations of British Army medics on the understanding of the parasitic disorder. The majority of these people presented with epilepsy. Among the contributions of the army medics were establishing the diagnosis, initially by histological examination of subcutaneous and muscular infestation, and later by radiography, clarifying the prognosis and the role of medical and surgical treatments and uncovering the close relationship between the larval (cysticercosis) and adult (intestinal tapeworm) stages of T. solium.

Progress on the development of rapid diagnostic tests for foodborne neglected zoonotic helminthiases: A systematic review

BACKGROUND

Foodborne Neglected Zoonotic Helminths (FNZH) are parasites of both economic and public health importance. They include Taenia solium, Echinococcus granulosus sensu lato, Echinococcus multilocularis and Foodborne trematodes (FBT). FNZH are earmarked for major interventions for control, elimination and eradication. This systematic review highlights the progress towards development of rapid tests for the diagnosis of FNZH since 2010 when they were listed as neglected tropical diseases.

METHODOLOGY

A systematic search was conducted in three databases, World of Science, Embase and PubMed using the same search phrase. The search produced 480 hits. Three studies from back referencing were included. Only 22 of these met the inclusion criteria. Data was extracted from these and presented qualitatively.

RESULTS

Twenty-five rapid diagnostic tests were found to have been developed since 2010, eight for diagnosis of T. solium infections, eight for echinococcosis and nine for FBT infections. The rapid tests for diagnosing T. solium infections included six antibody detecting and two antigen detecting tests. They constitute a combination among them, with some tests providing qualitative, others quantitative results. Similarly, seven out of the eight rapid tests developed for Echinococcus infections were antibody detecting tests save for one loop mediated isothermal amplification test. All of them were qualitative tests. For FBT infections, nine rapid tests were described; two antibody and one nucleic acid detecting test for diagnosis of Fascioliasis; three nucleic acid detecting tests for Opisthorchiasis; one antibody detecting test for Paragonimiasis; and for Clonorchiasis, one antibody and one nucleic acid detecting test. The FBT infection rapid tests were all qualitative in nature. Most of these tests have not undergone field evaluation in endemic areas where they will be used most.

CONCLUSION

This review describes the development and evaluation of rapid diagnostic tests, while highlighting the need for in depth validations of the tools to determine how well they can perform in endemic areas.

Dispersion of Echinococcus granulosus eggs from infected dogs under natural conditions in Patagonia, Argentina

Cystic echinococcosis caused by Echinococcus granulosus is a major zoonosis of public health significance in the Patagonian region of Argentina. This investigation sought to test the hypothesis that the persistence and dispersion of the parasite eggs can be explained by physical and meteorological parameters along with final host infection and behaviour. This observational study was carried out over a five-year period within an enclosure where two dogs harbouring a worm burden ranging from 100 to 1000 mature adult E. granulosus, as well as two uninfected dogs, had previously been kept for six months. Environmental canine faeces, topsoil, pond water, and sediment samples were examined to control for the presence of eggs and coproantigens of the parasite using microscope-based techniques and copro-ELISA plus copro-Western Blot tests. The parasite eggs were detected up to 41 months later in faeces from infected dogs, soil and sediment, and coproantigen tests remained positive for up to 70 months in faeces. Overall, parasite eggs were found within a maximum distance of 115 m from the contaminated dog faeces deposition site. Our findings indicate that under Patagonian environmental conditions, egg persistence and dispersion seem to be related to the worm burden and habits of the infected dog, to prevailing wind direction and to the existence of low bushes as well as natural bodies of water. The present study is the first to provide direct evidence of interaction between bioclimatic conditions and E. granulosus egg dispersion under Patagonian field conditions.

Clinical presentation of neurocysticercosis-related epilepsy

Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system and a major risk factor for seizures and epilepsy. Seizure types in NCC vary largely across studies and seizure semiology is poorly understood. We discuss here the studies regarding seizure types and seizure semiology in NCC, and examine the clinical presentation in patients with NCC and drug-resistant epilepsy. We also provide evidence of the role of MRI and EEG in the diagnosis of NCC-related epilepsy. Focal seizures are reported in 60-90% of patients with NCC-related epilepsy, and around 90% of all seizures registered prospectively are focal not evolving to bilateral tonic-clonic seizures. A great number of cases suggest that seizure semiology is topographically related to NCC lesions. Patients with hippocampal sclerosis and NCC have different clinical and neurophysiological characteristics than those with hippocampal sclerosis alone. Different MRI protocols have allowed to better differentiate NCC from other etiologies. Lesions' stages might account on the chances of finding an interictal epileptiform discharge. Studies pursuing the seizure onset in patients with NCC are lacking and they are specially needed to determine both whether the reported events of individual cases are seizures, and whether they are related to the NCC lesion or lesions. This article is part of a Special Issue entitled "Neurocysticercosis and Epilepsy".

Liver cystic echinococcosis and human host immune and autoimmune follow-up: A review

Cystic echinococcosis (CE) is an infectious disease caused by the larvae of parasite Echinococcus granulosus (E. granulosus). To successfully establish an infection, parasite release some substances and molecules that can modulate host immune functions, stimulating a strong anti-inflammatory reaction to carry favor to host and to reserve self-survival in the host. The literature was reviewed using MEDLINE, and an open access search for immunology of hydatidosis was performed. Accumulating data from animal experiments and human studies provided us with exciting insights into the mechanisms involved that affect all parts of immunity. In this review we used the existing scientific data and discuss how these findings assisted with a better understanding of the immunology of E. granulosus infection in man. The aim of this study is to point the several facts that challenge immune and autoimmune responses to protect E. granulosus from elimination and to minimize host severe pathology. Understanding the immune mechanisms of E. granulosus infection in an intermediate human host will provide, we believe, a more useful treatment with immunomodulating molecules and possibly better protection from parasitic infections. Besides that, the diagnosis of CE has improved due to the application of a new molecular tool for parasite identification by using of new recombinant antigens and immunogenic peptides. More studies for the better understanding of the mechanisms of parasite immune evasion is necessary. It will enable a novel approach in protection, detection and improving of the host inflammatory responses. In contrast, according to the "hygiene hypothesis", clinical applications that decrease the incidence of infection in developed countries and recently in developing countries are at the origin of the increasing incidence of both allergic and autoimmune diseases. Thus, an understanding of the immune mechanisms of E. granulosus infection is extremely important.

Diagnostic strategies to reveal covert infections with intestinal helminths in dogs

Intestinal helminths are common in dogs in the United States, particularly non-treated dogs in animal shelters, but surveys by fecal flotation may underestimate their prevalence. To determine the prevalence of intestinal helminths and evaluate the ability of fecal flotation and detection of nematode antigen to identify those infections, contents of the entire gastrointestinal tract of 97 adult (>1year) dogs previously identified for humane euthanasia at two animal control shelters in northeastern Oklahoma, USA, were screened. All helminths recovered were washed in saline and fixed prior to enumeration and identification to genus and species. Fecal samples from each dog were examined by passive sodium nitrate (SG 1.33) and centrifugal sugar solution (SG 1.25) flotation. Fecal antigen detection assays were used to confirm the presence of nematode antigen in frozen fecal samples from 92 dogs. Necropsy examination revealed Ancylostoma caninum in 45/97 (46.4%), Toxocara canis in 11/97 (11.3%), Trichuris vulpis in 38/97 (39.2%), Dipylidium caninum in 48/97 (49.5%), and Taenia sp. in 7/97 (7.2%) dogs. Passive fecal flotation identified 38/45 (84.4%) A. caninum, 6/11 (54.5%) T. canis, 26/38 (68.4%) T. vulpis, 2/48 (4.2%) D. caninum, and 1/7 (14.3%) Taenia sp. infections, while centrifugal flotation combined with antigen detection assays identified A. caninum in 97.7% (43/44), T. canis in 77.8% (7/9), and T. vulpis in 83.3% (30/36) of infected dogs based on necropsy recovery of nematodes. Taken together, these data indicate that detection of nematode antigen is a useful adjunct to microscopic examination of fecal samples for parasite eggs, and that this approach can improve diagnostic sensitivity for intestinal nematode infections in dogs.

The 3Rs Concept: Time to Change How We Evaluate the Efficacy of Anthelmintics in Companion Animals

Experimental infections are required by current guidelines for investigating the efficacy of anthelmintics in dogs and cats. Recently, alternatives to experimental infections and the sacrificing of research dogs and cats have been evaluated, and novel conceptual investigations and methods of examination have been explored. Several of these approaches could potentially be used in efficacy studies for anthelmintics in dogs and cats. Here, we provide food for thought towards using new tools for evaluating the efficacy of anthelmintics in companion animals, for promoting the value of field trials, and for updating the existing guidelines for the efficacy testing of anthelmintics in dogs and cats.

Evaluation of the impact of 2 years of a dosing intervention on canine echinococcosis in the Alay Valley, Kyrgyzstan

Echinococcosis is a re-emerging zoonotic disease in Kyrgyzstan. In 2012, an echinococcosis control scheme was started that included dosing owned dogs in the Alay Valley, Kyrgyzstan with praziquantel. Control programmes require large investments of money and resources; as such it is important to evaluate how well these are meeting their targets. However, problems associated with echinococcosis control schemes include remoteness and semi-nomadic customs of affected communities, and lack of resources. These same problems apply to control scheme evaluations, and quick and easy assessment tools are highly desirable. Lot quality assurance sampling was used to assess the impact of approximately 2 years of echinococcosis control in the Alay valley. A pre-intervention coproELISA prevalence was established, and a 75% threshold for dosing compliance was set based on previous studies. Ten communities were visited in 2013 and 2014, with 18–21 dogs sampled per community, and questionnaires administered to dog owners. After 21 months of control efforts, 8/10 communities showed evidence of reaching the 75% praziquantel dosing target, although only 3/10 showed evidence of a reduction in coproELISA prevalence. This is understandable, since years of sustained control are required to effectively control echinococcosis, and efforts in the Alay valley should be and are being continued.

Human taeniasis: current insights into prevention and management strategies in endemic countries

Human taeniasis is a zoonotic condition resulting from infection with the adult stages of Taenia saginata ("beef tapeworm"), Taenia solium ("pork tapeworm") or Taenia asiatica ("Asian tapeworm"). Although these parasites have a worldwide distribution, the overwhelming burden is felt by communities in low- and middle-income countries. This is particularly true for T. solium, whereby infection of the central nervous system with the larval stage of the parasite (neurocysticercosis) is a major cause of acquired epilepsy in low-resource settings. With a focus on endemic countries, this review provides an insight into the prevention and management of human taeniasis, concluding with some recent case studies describing their implementation. Discussion of the opportunities and challenges regarding current fecal and serological diagnostic assays for detecting Taenia spp. highlights the importance of accurate and accessible diagnostic options for the field situation. The lack of long-term impact on the parasites' lifecycle from human anthelmintic treatment, coupled with the propensity for adverse reactions, highlights the importance of a "two-pronged" approach that considers the relevant animal hosts, particularly in the case of T. solium. Aside from the therapeutic options, this review reiterates the importance of adequate assessment and consideration of the associated behavioral and policy aspects around sanitation, hygiene and meat inspection that have been shown to support parasite control, and potential elimination, in endemic regions.

Laboratory Diagnosis of Echinococcus spp. in Human Patients and Infected Animals

Among the species composing the genus Echinococcus, four species are of human clinical interest. The most prevalent species are Echinococcus granulosus and Echinococcus multilocularis, followed by Echinococcus vogeli and Echinococcus oligarthrus. The first two species cause cystic echinococcosis (CE) and alveolar echinococcosis (AE) respectively. Both diseases have a complex clinical management, in which laboratory diagnosis could be an adjunctive to the imaging techniques. To date, several approaches have been described for the laboratory diagnosis and followup of CE and AE, including antibody, antigen and cytokine detection. All of these approaches are far from being optimal as adjunctive diagnosis particularly for CE, since they do not reach enough sensitivity and/or specificity. A combination of several methods (e.g., antibody and antigen detection) or of several (recombinant) antigens could improve the performance of the adjunctive laboratory methods, although the complexity of echinococcosis and heterogeneity of clinical cases make necessary a deep understanding of the host-parasite relationships and the parasite phenotype at different developmental stages to reach the best diagnostic tool and to make it accepted in clinical practice. Standardization approaches and a deep understanding of the performance of each of the available antigens in the diagnosis of echinococcosis for the different clinical pictures are also needed. The detection of the parasite in definitive hosts is also reviewed in this chapter. Finally, the different methods for the detection of parasite DNA in different analytes and matrices are also reviewed.

Seroprevalence and risk factors of human cysticercosis and taeniasis prevalence in a highly endemic area of epilepsy in Bangoua, west Cameroon

Cysticercosis caused by the larvae of Taenia solium is a serious and emerging threat to public health in the endemic areas as well as in the non-endemic areas.　Neurocysticercosis, an affection of the central nervous system is a leading cause of epilepsy in endemic areas. This study was carried out to investigate human cysticercosis, taeniasis and risk factors, and also their association with epilepsy in Bangoua, west Cameroon where epilepsy is highly prevalent. Out of 384 people investigated, 12 (3.1%) exhibited antibody response against low molecular weight antigens of T. solium by ELISA. Immunoblot revealed that six persons (1.6%) were seropositive with the same antigens. Among 61 epileptic patients, only one was seropositive by immunoblot and the study did not find any statistically significant difference (P>0.05) in seropositivity to T. solium between epileptic persons (1/61, 1.6%) and non-epileptic group (5/323, 1.5%). In addition, cysticercosis was associated with households eating pork meat from pigs slaughtered at home, but not with other factors. The risk factors including pig farming, the consumption of pork meat, vegetables, and non-drinkable water were attenuated by the relatively good hygiene and pig husbandry practices of the population. No egg of Taenia was found in stool by microscopic examination. All data obtained in this study suggested that cysticercosis might not be the principal causative agent of epilepsy in this area.

Reprint of "Assessing the impact of a joint human-porcine intervention package for Taenia solium control: Results of a pilot study from northern Lao PDR"

Following confirmation that a remote village of approximately 300 inhabitants in northern Lao PDR was hyperendemic for the Neglected Tropical Disease Taenia solium, a pilot human-porcine therapeutic control intervention was implemented between October 2013 and November 2014. Mass drug administration with a three day albendazole 400mg protocol was offered to all eligible humans in October 2013 and March 2014. At these times, and again in October 2014, eligible village pigs received the anti-cysticercosis TSOL18 vaccination and an oral dose of oxfendazole anthelmintic at 30mg/kg, both repeated one month later. Community and individual human taeniasis prevalences were estimated via copro-antigen ELISA of volunteered human faecal samples prior to October 2013, and again in January 2015, in order to examine the short term impact of the intervention.

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.

Historical Aspects of Echinococcosis

Echinococcosis is a zoonosis whose history dates back to antiquity. This article provides an overview on the general history of echinococcosis, including the elucidation of Echinococcus life cycles and the long controversy on the aetiology of the cystic and alveolar forms of echinococcosis (CE and AE), lasting about 100years since the middle of the 19th century. Furthermore, selected historical aspects of some fields of echinococcosis research are discussed and compared with our current knowledge, such as geographic distribution and epidemiology of CE (Echinococcus granulosus) and AE (Echinococcus multilocularis), clinical aspects and pathology, diagnosis in humans and animals, treatment (with focus on chemotherapy), control and basic research. A short paragraph is devoted to the neotropical forms of echinococcosis, caused by Echinococcus vogeli and Echinococcus oligarthrus. In this context the achievements of some ancestral pioneers of echinococcosis research are particularly highlighted and appreciated. Finally, the role of associations, international organizations (World Health Organization and others) and international working groups in echinococcosis research and control is briefly outlined. The retrospective reveals both the admirable achievements of our ancestors and the scientific progress of more recent times. But, it also shows the gaps in our knowledge, skills and resources that we need to control or even eradicate echinococcosis.

Seasonal pattern of Echinococcus re-infection in owned dogs in Tibetan communities of Sichuan, China and its implications for control

BACKGROUND

Human cystic echinococcosis (CE) and alveolar echinococcosis (AE) are highly endemic in Tibetan communities of Sichuan Province. Previous research in the region indicated that domestic dog was the major source of human infection, and observations indicated that domestic dog could have more access to intermediate hosts of Echinococcus spp.: both domestic livestock (CE) viscera and small mammals (AE), in early winter and again in spring. We hypothesized that there would therefore be a significant increase in the risk of canine infection with Echinococcus spp. in these two seasons and conducted a reinfection study to investigate this further.

METHODS

Faecal samples were collected from owned dogs in seven townships in Ganze Tibetan Autonomous Prefecture (Sichuan Province, China), and Echinococcus spp. infection status was determined using copro-antigen ELISA. Dogs were sampled in April (spring), July (early summer), September/October (autumn/early winter) and December (winter) in 2009; and in April (spring) 2010. Dogs were treated with praziquantel following each of the five sample collections to eliminate any tapeworms. Information on dog sex, age and body weight was also collected. The t-test, Fisher's exact test, Poisson regression and logistic regression were used to compare means and prevalences, and to identify factors associated with infection status.

RESULTS

The proportion of female dogs was significantly lower than that of male dogs; female dogs had significantly higher (22.78 %) baseline copro-ELISA prevalence than males (11.88 %). Dog body weight, sex, age, county and previous infection status at any sampling point had no influence on the re-infection prevalence in general. Poisson regression did not found a significant influence on the re-infection prevalence due to different deworming/sampling time spans. Dogs exhibited significantly higher re-infection prevalences in spring and early summer of 2009 and in early winter between September/October and December of 2009, suggesting a higher infection pressure in these seasons comparing with other seasons.

CONCLUSION

Following praziquantel treatment, dog body weight, sex, age, county, deworming time span and previous infection status at any sampling point had no influence on the re-infection prevalence in the region in general. The differences between re-infection prevalences were probably due to the seasonality in Echinoccocus spp. infection pressure in the region. Early winter, spring and early summer should be important seasons for optimal dog deworming intervention in these Tibetan communities.

Assessing the impact of a joint human-porcine intervention package for Taenia solium control: Results of a pilot study from northern Lao PDR

Following confirmation that a remote village of approximately 300 inhabitants in northern Lao PDR was hyperendemic for the Neglected Tropical Disease Taenia solium, a pilot human-porcine therapeutic control intervention was implemented between October 2013 and November 2014. Mass drug administration with a three day albendazole 400mg protocol was offered to all eligible humans in October 2013 and March 2014. At these times, and again in October 2014, eligible village pigs received the anti-cysticercosis TSOL18 vaccination and an oral dose of oxfendazole anthelmintic at 30mg/kg, both repeated one month later. Community and individual human taeniasis prevalences were estimated via copro-antigen ELISA of volunteered human faecal samples prior to October 2013, and again in January 2015, in order to examine the short term impact of the intervention.

Risk factors for Echinococcus coproantigen positivity in dogs from the Alay valley, Kyrgyzstan

Echinococcosis, caused by the zoonotic cestodes Echinococcus granulosus (sensu lato) and Echinococcus multilocularis, is highly endemic in the Central Asian Republic of Kyrgyzstan, and is being identified increasingly as a public health problem, especially amongst pastoral communities. As domestic dogs are considered to be the main source of human infection, the identification of potential transmission pathways is of relevance when considering implementing an echinococcosis control scheme. The current report describes the results of an analytical study of canine Echinococcus coproantigen enzyme-linked immunosorbent assay (ELISA) prevalence in the Alay valley of southern Kyrgyzstan prior to the commencement of regular praziquantel dosing of dogs. A logistic regression model using a form of Bayes modal estimation was used to identify possible risk factors for coproantigen positivity, and the output was interpreted in a Bayesian context (posterior distributions of the coefficients of interest). The study found that sheepdogs had lower odds of coproantigen positivity, as did dogs in households with donkeys, where owners had knowledge of echinococcosis, and households which engaged in home slaughtering. Surprisingly, there was no evidence of an association between free roaming or previous praziquantel dosing and coproantigen positivity, as has been found in previous studies. Possible reasons for these findings are discussed in the context of the epidemiology of echinococcosis and potential intervention approaches.

Sero-diagnosis of Echinococcus granulosus infection in dogs using faecal supernatant antigen

In the present study, sero-diagnosis of Echinococcus granulosus infection in dogs was studied using 250 field serum samples, collected from stray dogs. The three serological techniques viz., latex agglutination test (LAT), Dot-ELISA and enzyme immunotransfer blot (EITB) were used to detect E. granulosus specific anti-bodies using fecal supernatant antigen. The LAT detected positivity in 53 (21.2 %) serum samples with the sensitivity and specificity of 100 and 78.80 % respectively. Whereas, the Dot-ELISA, showed positivity in 45 (18.0 %) samples and the sensitivity and specificity were 100 and 82.0 % respectively. The specific antibodies were detected in 47 (18.80 %) serum samples by EITB and the polypeptides of 45 and 34 kDa were identified in all the positive serum samples. The sensitivity and specificity of EITB were found to be 100 and 86.80 %, respectively.

Echinococcus granulosus: Epidemiology and state-of-the-art of diagnostics in animals

Diagnosis and detection of Echinococcus granulosus (sensu lato) infection in animals is a prerequisite for epidemiological studies and surveillance of echinococcosis in endemic, re-emergent or emergent transmission zones. Advances in diagnostic approaches for definitive hosts and livestock, however, have not progressed equally over the last 20 years. Development of laboratory based diagnostics for canids using coproantigen ELISA and also coproPCR, have had a huge impact on epidemiological studies and more recently on surveillance during hydatid control programmes. In contrast, diagnosis of cystic echinococcosis (CE) in livestock still relies largely on conventional post-mortem inspection, despite a relatively low diagnostic sensitivity especially in early infections, as current serodiagnostics do not provide a sufficiently specific and sensitive practical pre-mortem alternative. As a result, testing of dog faecal samples by coproantigen ELISA, often combined with mass ultrasound screening programmes for human CE, has been the preferred approach for monitoring and surveillance in resource-poor endemic areas and during control schemes. In this article we review the current options and approaches for diagnosis of E. granulosus infection in definitive and animal intermediate hosts (including applications in non-domesticated species) and make conclusions and recommendations for further improvements in diagnosis for use in epidemiological studies and surveillance schemes.

Canine echinococcosis: genetic diversity of Echinococcus granulosus sensu stricto (s.s.) from definitive hosts

Canids, particularly dogs, constitute the major source of cystic echinococcosis (CE) infection to humans, with the majority of cases being caused by Echinococcus granulosus (G1 genotype). Canine echinococcosis is an asymptomatic disease caused by adult tapeworms of E. granulosus sensu lato (s.l.). Information on the population structure and genetic variation of adult E. granulosus is limited. Using sequenced data of the mitochondrial cytochrome c oxidase subunit 1 (cox1) we examined the genetic diversity and population structure of adult tapeworms of E. granulosus (G1 genotype) from canid definitive hosts originating from various geographical regions and compared it to that reported for the larval metacestode stage from sheep and human hosts. Echinococcus granulosus (s.s) was identified from adult tapeworm isolates from Kenya, Libya, Tunisia, Australia, China, Kazakhstan, United Kingdom and Peru, including the first known molecular confirmation from Gaza and the Falkland Islands. Haplotype analysis showed a star-shaped network with a centrally positioned common haplotype previously described for the metacestode stage from sheep and humans, and the neutrality indices indicated population expansion. Low Fst values suggested that populations of adult E. granulosus were not genetically differentiated. Haplotype and nucleotide diversities for E. granulosus isolates from sheep and human origin were twice as high as those reported from canid hosts. This may be related to self-fertilization of E. granulosus and/or to the longevity of the parasite in the respective intermediate and definitive hosts. Improved nuclear single loci are required to investigate the discrepancies in genetic variation seen in this study.

Taenia saginatataeniosis: copro-antigen time-course in a voluntary self-infection

Human taeniosis due toTaenia saginatais cosmopolitan where beef is consumed; however, there is little or no information on the symptomatology over the early time-course of human infection. Copro-antigen detection is very useful in community screening for human taeniosis, particularly forT. solium, but there are no data on copro-antigen detection in pre-patent infection. In order to provide insight into this, a voluntary self-infection withT. saginatawas undertaken and monitored over a 6-month period using a copro-antigen enzyme-linked immunosorbent assay (ELISA) that we developed using anti-T. saginataantibody based reagents. Tapeworm patency, defined as first proglottid appearance, occurred on day 86 post-infection (pi) and was followed by almost daily release of proglottids (range 1–8) until termination using praziquantel on day 180 pi. The first 10 weeks post-infection (wpi) were essentially asymptomatic, followed by main symptoms of involuntary proglottid discharge throughout the infection period, and abdominal discomfort peaking around 15–19 wpi. Copro-antigens could not be reliably detected until 2 weeks before proglottid patency but then remained highly elevated over the next 15 weeks until treatment. Copro-antigen levels reverted to negative 4 days post-treatment. This time-course study suggests that although copro-antigen ELISA is an excellent diagnostic tool for established patent infections ofT. saginata, it may not be reliable for faecal antigen detection in the early infection phase prior to proglottid release forT. saginataand other human taenioses.

Laboratory assessment of sensitive molecular tools for detection of low levels of Echinococcus multilocularis-eggs in fox (Vulpes vulpes) faeces

Background

In endemic areas with very low infection prevalence, the frequency and intensity of Echinococcus multilocularis can be extremely low. This necessitates efficient, specific and sensitive molecular tools. We wanted to compare the existing molecular tools, used in the Norwegian national surveillance programme, and compare these with new techniques for detection of this zoonotic pathogen in fox faeces. Here we present the results of screening samples containing a known level of E. multilocularis eggs with two highly sensitive DNA isolation and extraction methods combined with one conventional PCR and three real-time PCR methods for detection.

Methods

We performed a comparison of two extraction protocols; one based on sieving of faecal material and one using targeted DNA sampling. Four methods of molecular detection were tested on E. multilocularis-egg spiked fox faeces.

Results

There were significant differences between the multiplex PCR/egg sieving DNA extraction methods compared to the new DNA fishing method and the three real-time PCR assays. Results also indicate that replicates of the PCR-reactions improve detection sensitivity when egg numbers are low.

Conclusions

The results indicate that the use of real-time PCR combined with targeted DNA extraction, improves the sensitivity of E. multilocularis detection in faecal samples containing low numbers of E. multilocularis eggs. Results also indicate the importance of replicates of the PCR-reactions when pathogen levels are low.

Investigating a hyper-endemic focus of Taenia solium in northern Lao PDR

Background

The Taenia solium cysticercosis-taeniasis complex is a Neglected Tropical Disease of significant public health importance in many impoverished communities worldwide. The parasite is suspected to be endemic in Lao PDR as a result of widespread risk factors including open human defecation, free ranging pigs and weak systems for meat inspection and carcass condemnation. Reported prevalences of human taeniasis throughout the country have ranged from 0-14%, although few of these have definitively diagnosed T. solium, grossly indistinguishable from Taenia saginata (beef tapeworm) and Taenia asiatica. This short communication details the suspicion of a hyper endemic “hotspot” of T. solium in a remote Tai Dam village in northern Lao PDR.

Findings

Initial antibody serosurveillance of four provinces in Lao PDR in 2011 indicated human taeniasis and cysticercosis prevalences of 46.7% and 66.7% respectively, in the village of Om Phalong in the north of the country. Subsequent copro-antigen ELISA on 92 human faecal samples from this same village, representing a total 27.9% of the target community, indicated a taeniasis prevalence of 26.1% (95% CI?=?18.2-35.9). Subsequent PCR and sequencing of samples (n?=?5) all identified as T. solium; the other human tapeworms T. saginata and T. asiatica were not detected in any of the samples genotyped.

Conclusion

This is potentially one of the highest documented prevalences of T. solium taeniasis to date in Lao PDR, if not the Southeast Asia region. This result raises suspicion that other “hotspots” of T. solium hyper endemicity may exist in the region, particularly in communities where the consumption of raw pork is commonplace as a result of cultural practices.

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.

Improved performance and quantitative detection of copro-antigens by a monoclonal antibody based ELISA to diagnose human opisthorchiasis

Copro-antigen detection has been advocated as a promising method for diagnosis of opisthorchiasis, particularly in people that harbored light infection or have had recent drug treatment. This study aimed to improve performance of a monoclonal antibody-based enzyme-linked immunosorbent assay (Mab-ELISA) for detection of Opisthorchis viverrini copro-antigen and assess the correlation between copro-antigen and intensity of infection. Four different treatment methods of 71 samples from the Lawa endemic area, Khon Kaen province were assessed for copro-antigen detection, namely (1) phosphate buffer saline (PBS), (2) heating (70°C 30min), (3) alkaline (pH 9.6 in carbonate buffer), and (4) trichloroacetic acid (TCA) treatment. Comparison of these protocols showed that the TCA method gave the best performance in discriminating O. viverrini positive and negative samples with high sensitivity (97.9%) and moderate specificity (54.2%) compared with other methods. Application of TCA-based Mab-ELISA method for antigen detection in fecal samples obtained from an endemic area of opisthorchiasis revealed that 86 of 141 samples (61.0%) were positive compared with 68 (48.2%) by PBS-based protocol, while the formalin ethyl-acetate concentration technique (FECT) yielded a positive proportion of 71.6%. Among 40 egg-negative samples confirmed by a gold standard parasitological method (FECT) from the same endemic area, 19 (47.5%) were positive by the TCA-based while only 6 (15%) were positive by PBS-based Mab-ELISA protocol. In addition, levels of antigen detection significantly correlated with intensity of infection (egg per gram feces). The results show that the improved Mab-ELISA method has high sensitivity and also quantifiable diagnosis of opisthorchiasis.

Advances in diagnosis and spatial analysis of cysticercosis and taeniasis

Human cysticercosis, caused by accidental ingestion of eggs of Taenia solium, is one of the most pathogenic helminthiases and is listed among the 17 WHO Neglected Tropical Diseases. Controlling the life-cycle of T. solium between humans and pigs is essential for eradication of cysticercosis. One difficulty for the accurate detection and identification of T. solium species is the possible co-existence of two other human Taenia tapeworms (T. saginata and T. asiatica, which do not cause cysticercosis in humans). Several key issues for taeniasis/cysticercosis (T/C) evidence-based epidemiology and control are reviewed: (1) advances in immunological and molecular tools for screening of human and animals hosts and identification of Taenia species, with a focus on real-time detection of taeniasis carriers and infected animals in field community screenings, and (2) spatial ecological approaches that have been used to detect geospatial patterns of case distributions and to monitor pig activity and behaviour. Most recent eco-epidemiological studies undertaken in Sichuan province, China, are introduced and reviewed.

Detection of human taeniases in Tibetan endemic areas, China

Detection of taeniasis carriers ofTaenia soliumis essential for control of cysticercosis in humans and pigs. In the current study, we assessed the positive detection rate of a self-detection tool, stool microscopy with direct smear and coproPCR for taeniasis carriers in endemic Tibetan areas of northwest Sichuan. The self-detection tool through questioning about a history of proglottid expulsion within the previous one year showed an overall positive detection rate of more than 80% forTaenia saginata, T. soliumandT. asiatica. The positive detection rate was similar forT. saginataandT. solium. In 132 taeniid tapeworm carriers, 68 (51·5%) were detected by microscopy and 92 (69·7%) were diagnosed by coproPCR. A combination of microscopy and coproPCR increased the positive detection rate to 77·3%. There remained 10 cases (7·6%) coproPCR negative but microscopy positive. Due to the high cost and complicated process, coproPCR is required for the identification ofTaeniaspecies only when necessary, though it had a significant higher positive detection rate than microscopy. Combined use of self-detection and stool microscopy are recommended in community-based mass screening for taeniases in this Tibetan area or in other situation-similar endemic regions.

Nothing is perfect! Trouble-shooting in immunological and molecular studies of cestode infections

This personal review focuses on ways to approach and overcome some of the more common issues encountered while studying cestode zoonoses. The information presented here is based on the author's own experiences with immunological and molecular approaches for the detection of these parasites. There are many incongruities between immunological and molecular studies due to biased work. Nothing is perfect. Indirect approaches using either immunological, or even molecular tools, are limited without confirmation from direct evidence of infection. The dilemma of whether developing countries should develop their own diagnostic tests or rely on commercially available kits is also discussed.

Prevalence and risk factors associated with human Taenia solium infections in Mbozi District, Mbeya Region, Tanzania

Background

Taenia solium cysticercosis/taeniosis is emerging as a serious public health and economic problem in many developing countries. This study was conducted to determine prevalence and risk factors of human T. solium infections in Mbeya Region, Tanzania.

Methods and Findings

A cross-sectional survey was conducted in 13 villages of Mbozi district in 2009. Sera of 830 people (mean 37.9±11.3 years (SD); 43% females) were tested for circulating cysticerci antigen (Ag-ELISA) and antibody (Ab-ELISA). A subset of persons found seropositive by Ag-ELISA underwent computed tomography (CT) scan of the brain for evidence of neurocysticercosis. Stool samples from 820 of the same participants were tested for taeniosis by copro-antigens (copro-Ag-ELISA) and formol-ether concentration technique. Cases of T. solium taeniosis were confirmed serologically by EITB assay (rES38). A questionnaire was used for identification of risk factors. Active cysticercosis by positive Ag-ELISA was found in 139 (16.7%) persons while anti-cysticercal antibodies were detected in 376 (45.3%) persons by Ab-ELISA. Among 55 persons positive for Ag-ELISA undergoing CT scan, 30 (54.6%) were found to have structures in the brain suggestive of neurocysticercosis. Using faecal analysis, 43 (5.2%) stool samples tested positive for taeniosis by copro-Ag-ELISA while Taenia eggs were detected in 9 (1.1%) stool samples by routine coprology. Antibodies specifically against adult T. solium were detected in 34 copro-Ag-ELISA positive participants by EITB (rES38) indicating T. solium taeniosis prevalence of 4.1%. Increasing age and hand washing by dipping in contrast to using running water, were found associated with Ag-ELISA seropositivity by logistic regression. Gender (higher risk in females) and water source were risk factors associated with Ab-ELISA seropositivity. Reported symptoms of chronic severe headaches and history of epileptic seizures were found associated with positive Ag-ELISA (p≤0.05).

Conclusion

The present study indicates T. solium infection in humans is highly endemic in the southern highlands of Tanzania.

Cysticercosis caused by the zoonotic pork tapeworm, Taenia solium, is emerging as a serious public health and agricultural problem in sub-Saharan Africa. Surveys have shown cysticercosis in pigs to be highly prevalent in multiple foci in Tanzania, and a hospital-based study in the northern highlands indicated neurocysticercosis as an important cause of epileptic seizures in humans. We present here a cross-sectional community-based survey on the prevalence and risk factors of human cysticercosis and taeniosis conducted in the southern highlands – the major pig-producing area of the country. The most striking findings were that more than 15% of people surveyed were found to have active cysticercosis and nearly half of them were found to have been exposed to larval T. solium indicating a high level of environmental contamination with T. solium eggs. This was supported by finding over 4% of people having had T. solium tapeworms. A subset of persons found positive serologically for active cysticercosis underwent brain scanning and more than half of them were found to have neurocysticercosis. This strong evidence that T. solium cysticercosis/neurocysticercosis/taeniosis is highly endemic in the southern highlands of Tanzania demands urgent attention of regional and national authorities to combat the parasite.

A monoclonal antibody-based copro-ELISA kit for canine echinococcosis to support the PAHO effort for hydatid disease control in South America

Cystic echinococcosis is still a major concern in South America. While some regions show advances in the control of the disease, others have among the highest incidence in the world. To reverse this situation the Pan American Health Organization (PAHO) has launched a regional project on cystic echinococcosis control and surveillance. An early concern of the program was the lack of a standardized diagnostic tool to monitor infection in dogs, a key target of control programs. Under this premise, we have developed a new copro-ELISA test after extensive screening of a large panel of monoclonal antibodies (MAbs) and polyclonal sera, which performs with high standards of sensitivity (92.6%) and specificity (86.4%) as established by necropsy diagnosis of dogs. The key component of the test, MAbEg9 has a convenient IgG isotype and reacts with a periodate-resistant epitope found in high molecular weight components of the worm. Time-course analysis of experimentally infected dogs showed that even animals with a very low number of parasites could be detected as early as day 20 post infection. The test was formulated in a ready-to-use kit format with proven stability of each component for a minimum of 3 months at room temperature. This characteristic facilitates its standardized use and shipping to other laboratories, which was demonstrated by the identical results obtained by two different laboratories in Peru and our own laboratory when a large number of field samples were analyzed independently in a blind fashion.

Cystic echinococcosis, caused by infection with the larval stage of the Echinococcus granulosus tapeworm, is a life-threatening zoonosis of worldwide distribution. The adult worm parasitizes the small intestine of dogs, which become infected after eating offal of an animal contaminated with the parasite, and releases eggs into the environment that can be accidentally ingested by domestic animals or humans, maintaining the life cycle of the parasite. Deworming of dogs is a major component of control programs, and simple and reliable methods are needed to monitor the base-line infection in the canine population. The lack of these tests was recognized as a major obstacle to the PAHO effort to control the disease in South America. This paper describes the development of a diagnostic assay that detects parasite antigens in dog feces. The key component is a monoclonal antibody carefully selected to attain high levels of sensitivity and specificity, which were established with a large panel of field fecal samples obtained from animals diagnosed by necropsy. Several aspects of the long-term stability of the test were optimized to facilitate its shelf-life and transference to other laboratories.

Field evaluation of a coproantigen detection test for fascioliasis diagnosis and surveillance in human hyperendemic areas of Andean countries

Background

Emergence of human fascioliasis prompted a worldwide control initiative including a pilot study in a few countries. Two hyperendemic areas were chosen: Huacullani, Northern Altiplano, Bolivia, representing the Altiplanic transmission pattern with high prevalences and intensities; Cajamarca valley, Peru, representing the valley pattern with high prevalences but low intensities. Coprological sample collection, transport and study procedures were analyzed to improve individual diagnosis and subsequent treatments and surveillance activities. Therefore, a coproantigen-detection technique (MM3-COPRO ELISA) was evaluated, using classical techniques for egg detection for comparison.

Methodology and Findings

A total of 436 and 362 stool samples from schoolchildren of Huacullani and Cajamarca, respectively, were used. Positive samples from Huacullani were 24.77% using the MM3-COPRO technique, and 21.56% using Kato-Katz. Positive samples from Cajamarca were 11.05% using MM3-COPRO, and 5.24% using rapid sedimentation and Kato-Katz. In Huacullani, using Kato-Katz as gold standard, sensitivity and specificity were 94.68% and 98.48%, respectively, and using Kato-Katz and COPRO-ELISA test together, they were 95.68% and 100%. In Cajamarca, using rapid sedimentation and Kato-Katz together, results were 94.73% and 93.58%, and using rapid sedimentation, Kato-Katz and copro-ELISA together, they were 97.56% and 100%, respectively. There was no correlation between coproantigen detection by optical density (OD) and infection intensity by eggs per gram of feces (epg) in Cajamarca low burden cases (<400 epg), nor in Huacullani high burden cases (≥400 epg), although there was in Huacullani low burden cases (<400 epg). Six cases of egg emission appeared negative by MM3-COPRO, including one with a high egg count (1248 epg).

Conclusions

The coproantigen-detection test allows for high sensitivity and specificity, fast large mass screening capacity, detection in the chronic phase, early detection of treatment failure or reinfection in post-treated subjects, and usefulness in surveillance programs. However, this technique falls short when evaluating the fluke burden on its own.

A coproantigen-detection technique (MM3-COPRO ELISA) was evaluated in 436 and 362 schoolchildren of Huacullani, Bolivia, and Cajamarca valley, Peru, respectively. Classical techniques for egg detection were used for comparison. In Huacullani, using Kato-Katz as gold standard, sensitivity and specificity were 94.68% and 98.48%, respectively, and using Kato-Katz and COPRO-ELISA test together, they were 95.68% and 100%, respectively. In Cajamarca, using rapid sedimentation and Kato-Katz together, these results were 94.73% and 93.58%, respectively, and using rapid sedimentation, Kato-Katz and copro-ELISA together, results were 97.56% and 100%, respectively. There was no correlation between coproantigen detection by optical density (OD) and infection intensity by eggs per gram of feces (epg) in Cajamarca low burden cases (<400 epg), nor in Huacullani high burden cases (≥400 epg), although there was in Huacullani low burden cases (<400 epg). Six cases of egg emission appeared negative by MM3-COPRO, including one with a high egg count (1248 epg). The coproantigen-detection test allows for high sensitivity and specificity, fast large mass screening capacity, detection in the chronic phase, early detection of treatment failure or reinfection in post-treated subjects, and usefulness for surveillance programs. However, this technique falls short when evaluating the fluke burden on its own.

Seroprevalence of antibodies against Taenia solium cysticerci among refugees resettled in United States

Cysticercosis is an infection caused by a pork tapeworm that creates cysts in different areas of the human body. Sometimes, these parasites can get into the infected patient’s brain and lead to epilepsy or other neurologic disorders. Cysticercosis is most common in developing countries that have poor sanitation and where pigs feed on human waste; however, cases in the United States are increasing. A recent study found that many refugees who settle in the United States, including those from Burma, Laos, Burundi, and Bhutan, have been infected with the tapeworm. The occurrence of cysticercosis among these groups has clinical and public health implications because US physicians might not be familiar with this disease and its symptoms. Cysticercosis should be suspected in refugees who have seizures, headache, or other unexplained neurologic symptoms. Physicians should also be aware that treatment for intestinal parasites, routinely given to refugees before they leave their homeland, can cause serious neurologic reactions in those already infected with the tapeworm.

Neurocysticercosis (NCC) is a disease caused by central nervous system infection by the larval stage of the pork tapeworm, Taenia solium. In developing countries, NCC is a leading cause of adult-onset epilepsy. Case reports of NCC are increasing among refugees resettled to the United States and other nations, but the underlying prevalence among refugee groups is unknown. We tested stored serum samples from the Centers for Disease Control and Prevention Migrant Serum Bank for antibodies against T. solium cysts by using the enzyme-linked immunoelectrotransfer blot. Seroprevalence was high among all 4 populations tested: refugees from Burma (23.2%), Lao People’s Democratic Republic (18.3%), Bhutan (22.8%), and Burundi (25.8%). Clinicians caring for refugee populations should suspect NCC in patients with seizure, chronic headache, or unexplained neurologic manifestations. Improved understanding of the prevalence of epilepsy and other associated diseases among refugees could guide recommendations for their evaluation and treatment before, during, and after resettlement.

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.

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.

Taenia solium Infections in a rural area of Eastern Zambia-a community based study

Background

Taenia solium taeniosis/cysticercosis is a parasitic infection occurring in many developing countries. Data on the status of human infections in Zambia is largely lacking. We conducted a community-based study in Eastern Zambia to determine the prevalence of human taeniosis and cysticercosis in a rural community.

Methods and Findings

Stool and serum samples were collected from willing participants. Geographical references of the participants' households were determined and household questionnaires administered. Taeniosis was diagnosed in stool samples by coprology and by the polyclonal antibody-based copro-antigen enzyme-linked immunosorbent assay (copro-Ag ELISA), while cysticercosis was diagnosed in serum by the B158/B60 monoclonal antibody-based antigen ELISA (sero-Ag ELISA). Identification of the collected tapeworm after niclosamide treatment and purgation was done using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). A total of 255 households from 20 villages participated in the study, 718 stool and 708 serum samples were collected and examined. Forty-five faecal samples (6.3%) were found positive for taeniosis on copro-Ag ELISA while circulating cysticercus antigen was detected in 5.8% (41/708) individuals. The tapeworm recovered from one of the cases was confirmed to be T. solium on PCR-RFLP. Seropositivity (cysticercosis) was significantly positively related to age (p = 0.00) and to copro-Ag positivity (taeniosis) (p = 0.03) but not to gender. Change point analysis revealed that the frequency of cysticercus antigens increased significantly in individuals above the age of 30. Copro-Ag positivity was not related to age or gender. The following risk factors were noted to be present in the study community: free-range pig husbandry system and poor sanitation with 47.8% of the households visited lacking latrines.

Conclusions

This study has recorded high taeniosis and cysticercosis prevalences and identified the need for further studies on transmission dynamics and impact of the disease on the local people.

Taenia solium taeniosis/cysticercosis is a zoonotic infection endemic in many developing countries, with humans as the definitive host (taeniosis) and pigs and humans as the intermediate hosts (cysticercosis). When humans act as the intermediate host, the result can be neurocysticercosis, which is associated with acquired epilepsy, considerable morbidity and even mortality. In Africa, most studies have been carried out in pigs with little or no data in humans available. In this human study, conducted in a rural community in Eastern Zambia, prevalences for taeniosis and cysticercosis were determined at 6.3% and 5.8% respectively, indicating the hyperendemicity of the area. Cysticercosis infection was strongly related with age, with a significant increase in prevalence occurring in individuals from the age of 30 onward. A collected tapeworm was confirmed to be T. solium. Risk factors associated with the transmission and maintenance of the parasite such as free roaming pigs, households without latrines, backyard slaughter of pigs without inspection and consumption of undercooked pork were also present. The findings of this work have identified the need for further research in the transmission dynamics and the burden that this infection has on the resources of poor local people.