Present status of laboratory diagnosis of human taeniosis/cysticercosis in Europe

Evaluation of a rapid lateral flow assay for the detection of taeniosis and cysticercosis at district hospital level in Tanzania: A prospective multicentre diagnostic accuracy study

The TS POC test, Taenia solium point-of-care test, is a two-strip lateral flow assay using the recombinant antigen rES33 on the TS POC T test strip, and rT24H on the TS POC CC test strip, to detect antibodies against T. solium taeniosis and cysticercosis, respectively. The objective of this study was to assess the diagnostic performance of the TS POC test for the detection of T. solium taeniosis and cysticercosis in individuals attending district hospitals in Tanzania. In this prospective two-phase diagnostic accuracy study, we recruited participants aged 10 and above, excluding pregnant women and those with acute severe illness. Participants were consecutively recruited in three cohorts according to their signs/symptoms: compatible with neurocysticercosis (cohort 1), intestinal worm infections (cohort 2), and other signs/symptoms (cohort 3). Lacking a gold standard test for both infections, diagnostic accuracy was evaluated using results of two coprological and two serological tests for taeniosis, and three serological tests for cysticercosis, in a Bayesian Latent Class Model approach. The TS POC test was conducted on 601 participants in cohort 1, 1661 participants in cohort 2, and 662 participants in cohort 3. Most individuals tested negative on both TS POC test strips, with proportions of 83% (n = 496), 97% (n = 1613) and 97% (n = 641) in cohorts 1, 2 and 3, respectively. Complete case data were available for 120, 114, and 53 participants for taeniosis, and 126, 122, and 55 participants for cysticercosis. Sensitivity values for the TS POC T test strip were 50.2% [95% credible interval 4.9 - 96.4], 40.8% [2.2 - 95.2], and 40.4% [2.3 - 95.0], while specificity values were 98.6% [97.1 - 99.6], 99.3% [98.7 - 99.7] and 99.4% [98.5 - 99.9], respectively. For the TS POC CC test strip, the sensitivity was 77.5% [37.8 - 99.2], 24.9% [95% CI 6.4 - 52.7] and 44.2% [6.6 - 91.5], and the specificity 92.3% [86.5 - 98.8], 99.1% [97.8 - 100], and 98.1% [96.1 - 99.7] across the respective cohorts. Although the TS POC test has a low sensitivity, it demonstrates a high specificity, which may have clinical utility to guide treatment and diagnostic decisions, or in epidemiological studies. An important strength of this study lies in its assessment of the TS POC test under real-world conditions, revealing divergent estimates across distinct cohorts. The study underscores the suboptimal performance of existing tests under field conditions, emphasizing the need to enhance and validate these tests for better performance in practical real-world settings. Registration number: PACTR201712002788898.

From laboratory to clinical practice: an update of the immunological and molecular tools for neurocysticercosis diagnosis

Neurocysticercosis (NCC) is caused by the invasion of Taenia solium larvae in the central nervous system (CNS) and stands as the predominant cause of epilepsy and other neurological disorders in many developing nations. NCC diagnosis is challenging because it relies on brain imaging exams (CT or MRI), which are poorly available in endemic rural or resource-limited areas. Moreover, some NCC cases cannot be easily detected by imaging, leading to inconclusive results. Multiple laboratory assays, principally immunological, have been developed to support the diagnosis and/or monitor the treatment efficacy, but its production can be costly, laborious, and non-globally accessible because they depend on parasite material. Therefore, recent advances have been focused on the implementation of recombinant or synthetic antigens as well as monoclonal antibodies for NCC immunodiagnosis purposes. Similarly, molecular diagnosis has been explored, obtaining promising results. Here we described the recent progress in the development of immunological and molecular diagnostic tools for NCC diagnosis over the past 13 years, discussing their potential application to address important challenges and how to focus future directions to improve NCC diagnosis with emphasis on enhance accessibility and the importance of test validation to provide an adequate support for clinical decisions.

Emerging and Re-Emerging Parasitic Infections of the Central Nervous System (CNS) in Europe

In a rapidly evolving global landscape characterized by increased international travel, migration, and ecological shifts, this study sheds light on the emergence of protozoal and helminthic infections targeting the central nervous system (CNS) within Europe. Despite being traditionally associated with tropical regions, these infections are progressively becoming more prevalent in non-endemic areas. By scrutinizing the inherent risks, potential outcomes, and attendant challenges, this study underscores the intricate interplay between diagnostic limitations, susceptibility of specific population subsets, and the profound influence of climate fluctuations. The contemporary interconnectedness of societies serves as a conduit for introducing and establishing these infections, warranting comprehensive assessment. This study emphasizes the pivotal role of heightened clinician vigilance, judicious public health interventions, and synergistic research collaborations to mitigate the potential consequences of these infections. Though rare, their profound impact on morbidity and mortality underscores the collective urgency required to safeguard the neurological well-being of the European populace. Through this multifaceted approach, Europe can effectively navigate the complex terrain posed with these emergent infections.

Taenia solium taeniasis and Cysticercosis Prevalence and Control Practice in China

Taenia solium taeniasis/cysticercosis is an important global food-borne zoonosis transmitted between humans and pigs. In China, the prevalence of Theridion solium taeniasis/cysticercosis has been marked decline in recent decades based on the data revealed by both national surveys and field prevalence investigations. Health education and promotion, meat inspection, and chemotherapy are unquestionably the main control measures for diseases. It is worth noting that a variety of socio-ecological variables have been identified in the process of controlling T. solium taeniasis/cysticercosis. It has become difficult for pigs to come into direct or indirect contact with or consume human excreta as pig farming practices have been shifted from traditional backyard farms to large-scale commercial pig raising systems that are still in progress. The human toilet revolution in rural areas of China has ensured hygienic separation of human excreta from contact, and thereby preventing human excreta from polluting the soil, feeds, and water. These two important fundamental preventive measures are crucial to establishing an environmental restriction between humans and pigs cannot be overlooked for interrupting or limiting T. solium transmission. In this chapter, we reviewed the epidemiology, traditional measures, and ecological determinants that significantly contributed to the dramatic decline of taeniasis/cysticercosis in China.

The Novodiag® Stool parasites assay, an innovative high-plex technique for fast detection of protozoa, helminths and microsporidia in stool samples: a retrospective and prospective study

OBJECTIVES

We provide the first evaluation of the CE-IVD marked Novodiag® stool parasites assay (NVD), allowing rapid and high-plex detection of 26 distinct targets, encompassing protozoans, helminths and microsporidia in stool samples.

METHODS

A total of 254 samples (n = 205 patients) were prospectively processed by the NVD and our routine procedure (RP). Performances of the NVD were compared with RP. Samples only positive by the NVD assay were investigated by external PCR assays. Sensitivity and specificity (Se/Sp) and time from sample receipt to results were determined for each method. The NVD was also evaluated against 77 additional samples positive for a wide range of parasites.

RESULTS

Overall positivity rate was 16.9% for RP compared with 34% using the NVD assay, and 164 samples (66%) were negative by both methods. Only 30 positive samples (12%) showed full concordance between RP and NVD. Fifty-three discordant samples were sent for external investigations. Except for Giardia intestinalis and Trichuris spp., higher Se was observed for the NVD assay for Blastocystis spp. (100% vs. 63%), Dientamoeba fragilis (100% vs. 0%), Schistosoma spp. (100% vs. 17%), and Enterobius vermicularis (100% vs. 67%) but roughly similar to RP for the remaining parasites tested. False-positive results were identified for Blastocystis spp., G. intestinalis, and Trichuris spp. using the NVD assay. The NVD mostly provides a diagnosis on the day of sample receipt compared with a mean of three days with RP.

CONCLUSIONS

Besides some limitations, the NVD is a new diagnostic strategy allowing rapid and high-plex detection of gastrointestinal parasites from unpreserved stools.

Advances in the treatment, diagnosis, control and scientific understanding of taeniid cestode parasite infections over the past 50 years

In the past 50 years, enormous progress has been made in the diagnosis, treatment and control of taeniid cestode infections/diseases and in the scientific understanding thereof. Most interest in this group of parasites stems from the serious diseases that they cause in humans. It is through this lens that we summarize here the most important breakthroughs that have made a difference to the treatment of human diseases caused by these parasites, reduction in transmission of the taeniid species associated with human disease, or understanding of the parasites' biology likely to impact diagnosis or treatment in the foreseeable future. Key topics discussed are the introduction of anti-cestode drugs, including benzimidazoles and praziquantel, and the development of new imaging modalities that have transformed the diagnosis and post-treatment monitoring of human echinococcoses and neurocysticercosis. The availability of new anti-cestode drugs for use in dogs and a detailed understanding of the transmission dynamics of Echinococcus granulosus sensu lato have underpinned successful programs that have eliminated cystic echinococcosis in some areas of the world and greatly reduced the incidence of infection in others. Despite these successes, cystic and alveolar echinococcosis and neurocysticercosis continue to be prevalent in many parts of the world, requiring new or renewed efforts to prevent the associated taeniid infections. Major advances made in the development of practical vaccines against E. granulosus and Taenia solium will hopefully assist in this endeavour, as might the understanding of the parasites' biology that have come from an elucidation of the nuclear genomes of each of the most important taeniid species causing human diseases.

Collaborative Studies for the Detection of Taenia spp. Infections in Humans within CYSTINET, the European Network on Taeniosis/Cysticercosis

Laboratory tools for diagnosing taeniosis/cysticercosis in non-endemic countries are available; however, there is little data on their performance. To provide information on the sensitivity, specificity, and reproducibility of these tools, inter-laboratory studies were organized within the EU COST-Action CYSTINET (TD1302). Two serological and one coprological Ring Trials (RTs) were organized to test a panel of human-derived sera and stool samples using assays routinely conducted by the participating laboratories to detect Taenia spp. infections. Four Western blots (WBs) and five ELISAs were used by nine laboratories for cysticercosis diagnosis. In the first serological RT, the overall sensitivity was 67.6% (95% CI, 59.1-75.4), whereas specificity was 97% (95% CI, 89.8-99.6). WBs recorded the best accuracy. A second serological RT was organized, to assess the three tests most frequently used during the first RT. Two out of six laboratories performed all the three tests. The overall sensitivity and specificity were 52.8% (95% CI, 42.8-62.7) and 98.1% (95% CI, 93.2-99.7), respectively. Laboratory performance strongly affected test results. Twelve laboratories participated in the coprological RT using conventional microscopy and six laboratories used molecular assays. Traditional diagnosis by microscopy yielded better results than molecular diagnosis. This may have been influenced by the lack of standardization of molecular tests across participating laboratories.

Hospitalization for Chagas disease, dengue, filariasis, leishmaniasis, schistosomiasis, strongyloidiasis, and Taenia solium taeniasis/cysticercosis, Italy, 2011-2016

PURPOSE

To analyze epidemiology and burden of Neglected Tropical Diseases (NTDs) in Italy.

METHODS

We used Hospital Discharge Records and number of residents in Italy to calculate number and rate of hospitalization for Chagas disease, dengue, filariasis, leishmaniasis, schistosomiasis, strongyloidiasis, Taenia solium taeniasis, and cysticercosis by sex, citizenship group, and region in the period 2011-2016.

RESULTS

7195 hospitalizations for NTDs were retrieved, accounting for 7375 diagnoses, 60% in Italians and 40% in foreigners. Male-to-female ratio was 2; the age group more commonly affected was 25-44 years (32.5%). The most common diagnoses were leishmaniasis (34%), schistosomiasis (29%), strongyloidiasis (12%), Chagas disease (8%), and dengue (8%). Average yearly hospitalization rate per 100,000 residents for all NTDs was 2.05, 1.33, and 10.39 in general population, Italians, and foreign citizens, respectively. Hospitalization rates higher than 100 per 100,000 subjects were found in citizens from Sub-Saharan Africa (SSA) and Bolivia.

CONCLUSIONS

NTDs have a not negligible burden in Italy. The most clinically relevant NTDs in Italy are leishmaniasis and schistosomiasis, followed by strongyloidiasis, Chagas disease, and dengue. Cystic echinococcosis, that was not included in the analysis since a similar study on this disease was recently published, should also be listed among the leading NTD in Italy. While schistosomiasis has its highest burden on population coming from highly endemic areas such as SSA, leishmaniasis is especially relevant in Italian-born residents of southern regions. Education at university and post-graduate levels, to increase the awareness of healthcare professionals on these topics, as well as targeted public health interventions (such as screening or presumptive treatment in high-risk groups), are an asset to improve clinical management and control of these diseases.

Post-genomic progress in helminth parasitology

Helminth parasitology is an important discipline, which poses often unique technical challenges. One challenge is that helminth parasites, particularly those in humans, are often difficult to obtain alive and in sufficient quantities for study; another is the challenge of studying these organisms in vitro - no helminth parasite life cycle has been fully recapitulated outside of a host. Arguably, the key issue retarding progress in helminth parasitology has been a lack of experimental tools and resources, certainly relative to the riches that have driven many parasitologists to adopt free-living model organisms as surrogate systems. In response to these needs, the past 10-12 years have seen the beginnings of helminth parasitology's journey into the 'omics' era, with the release of abundant sequencing resources, and the functional genomics tools with which to test biological hypotheses. To reflect this progress, the 2019 Autumn Symposium of the British Society for Parasitology was held in Queen's University Belfast on the topic of 'post-genomic progress in helminth parasitology'. This issue presents examples of the current state of play in the field, while this editorial summarizes how genomic datasets and functional genomic tools have stimulated impressive recent progress in our understanding of parasite biology.

Epidemiology and surveillance of human (neuro)cysticercosis in Europe: is enhanced surveillance required?

OBJECTIVES

To report on relevant national surveillance systems of (N)CC and taeniasis (the infection with the adult tapeworm) in the European Union/European Economic Area and to assess the magnitude of (N)CC occurrence by retrieving information on cases for the period 2000-2016.

METHODS

(N)CC cases were retrieved via national reporting systems, a systematic literature search, contact with clinicians and a search for relevant 'International Statistical Classification of Diseases and Related Health Problems' (ICD)-based data.

RESULTS

Mandatory notification systems for (N)CC were found in Hungary, Iceland and Poland. Ten cases were reported in Poland and none in Hungary and Iceland. Through the systematic literature review and information given by clinicians, 263 individual and 721 aggregated (N)CC cases from 19 European countries were identified. ICD-based data were obtained from five countries. From 2000 to 2016, a total of 3489 cases (N)CC cases were coded: 832 in Italy, eight in Latvia, 357 in Portugal, 2116 in Spain and 176 in Sweden.

CONCLUSION

Despite being classified as a possible eradicable disease, (N)CC is still diagnosed across Europe, yet its true extent and impact remain unclear.

Epidemiology of taeniosis/cysticercosis in Europe, a systematic review: eastern Europe

BACKGROUND

Taenia solium and Taenia saginata are food-borne parasites of global importance. In eastern Europe only fragmented information is available on the epidemiology of these zoonotic parasites in humans and animal populations. In particular for T. solium, on-going transmission is suspected. The aim of this systematic review was to collect the available data and describe the current knowledge on the epidemiology of T. solium and T. saginata in eastern Europe.

METHODS

Literature published in international databases from 1990 to 2017 was systematically reviewed. Furthermore, local sources and unpublished data from national databases were retrieved from local eastern European experts. The study area included 22 countries.

RESULTS

Researchers from 18 out of the 22 countries provided data from local and unpublished sources, while no contacts could be established with researchers from Belarus, Kosovo, Malta and Ukraine. Taeniosis and human cysticercosis cases were reported in 14 and 15 out of the 22 countries, respectively. Estonia, the Former Yugoslav Republic of Macedonia, Lithuania, Moldova, Poland, Romania, Serbia, and Slovakia reported cases of porcine cysticercosis. Croatia, Czech Republic, Estonia, Former Yugoslav Republic of Macedonia, Moldova, Poland, Romania, Serbia, Slovakia, and Ukraine reported bovine cysticercosis.

CONCLUSIONS

There is indication that taeniosis and cysticercosis are present across eastern Europe but information on the occurrence of T. solium and T. saginata across the region remains incomplete. Available data are scarce and species identification is in most cases absent. Given the public health impact of T. solium and the potential economic and trade implications due to T. saginata, notification of taeniosis and human cysticercosis should be implemented and surveillance and notification systems in animals should be improved.

Human taeniasis/cysticercosis: a potentially emerging parasitic disease in Europe

Taenia saginata (T. saginata)/Taenia solium (T. solium) taeniasis/cysticercosis disease complexes remain a significant challenge for food safety and public health. Human taeniasis is an infectious disease caused by the ingestion of the metacestode larval stage, the cysticerci of T. saginata in beef or T. solium in pork. Humans can also become infected via the ingestion of T. solium eggs. In this case, the cysticerci can establish in the central nervous system, causing the infection called neurocysticercosis. T. solium is of higher importance than T. saginata because the former species can cause neurocysticercosis in humans, a major cause of neurological morbidity in the world. The taeniasis/cysticercosis complex is included in the list of neglected zoonotic diseases by the World Health Organization and Food and Agriculture Organization, with T. solium being the number one foodborne parasite; it occurs mostly in developing countries, such as regions of Asia, Africa and Latin America, where the disease remains endemic. Long absent in Western Europe and other developed countries, cysticercosis has been recently re-emerged as a result of immigration, travel and commerce. In this review, cysticercosis is presented with special emphasis on some aspects of this neglected disease: the main clinical manifestations, risk factors and epidemiology. In addition, any recent advances in diagnostic approaches and treatment are discussed. Finally, the complexities involved in the control of the disease and the need to revise current management strategies are highlighted.

Detection of Taenia saginata infection mimicking Crohn's disease using video capsule endoscopy

Capsule endoscopy was used to detect intestinal Taenia saginata infection in a 19-year-old man. The patient was initially believed to have Crohn's disease due to a notable family history of the disease. Capsule endoscopy is a valuable tool for diagnosing tapeworm infection even when Crohn's disease is suspected.

HDP2: a ribosomal DNA (NTS-ETS) sequence as a target for species-specific molecular diagnosis of intestinal taeniasis in humans

Background

Taenia solium, T. asiatica and T. saginata tapeworms cause human taeniasis and are the origin of porcine and bovine cysticercosis. Furthermore, T. solium eggs can cause human cysticercosis, with neurocysticercosis being the most serious form of the disease. These helminth infections are neglected tropical diseases and are endemic in several countries in the Americas, Asia and Africa. As a result of globalization, migration in particular, the infections have been extending to non-endemic territories. Species-specific diagnosis of taeniasis is subject to drawbacks that could be resolved using molecular approaches. In the present study, conventional and real-time amplification protocols (cPCR and qPCR) based on the T. saginata HDP2 sequence were applied in the differential diagnosis of taeniasis (T. saginata, T. solium) in both fecal samples and proglottids expelled by patients. The HDP2 homolog in T. solium was cloned and characterized.

Results

Semi-nested cPCR and qPCR (Sn-HDP2 cPCR and Sn-HDP2 qPCR) amplified T. saginata and T. solium DNA, with an analytical sensitivity of 40 and 400 fg, respectively, and identically in both protocols. Eighteen taeniasis patients were diagnosed directly with T. saginata or T. solium, either from proglottids or fecal samples with/without eggs (detected using microscopy), based on the optimized Sn-HDP2 qPCR. After cloning, the T. solium HDP2 homolog sequence was confirmed to be a ribosomal sequence. The HDP2 fragment corresponded to a non-transcribed sequence/external transcribed repeat (NTS/ETS) of ribosomal DNA. Compared with the T. saginata HDP2 homolog, the T solium HDP2 sequence lacked the first 900 nt at the 5′ end and showed nucleotide substitutions and small deletions.

Conclusions

Sn-HDP2 cPCR and Sn-HDP2 qPCR were set up for the diagnosis of human taeniasis, using proglottids and fecal samples from affected patients. The new Sn-HDP2 qPCR protocol was the best option, as it directly differentiated T. saginata from T. solium. The diagnosis of an imported T. solium-taeniasis case and nine European T. saginata cases was relevant. Finally, the cloning and sequencing of the T. solium HDP2 fragment confirmed that HDP2 was part of a ribosomal unit.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-2646-6) contains supplementary material, which is available to authorized users.

Low sensitivity and frequent cross-reactions in commercially available antibody detection ELISA assays for Taenia solium cysticercosis

OBJECTIVE

To evaluate the diagnostic performance of two commercially available ELISA kits, Novalisa^® and Ridascreen^® , for the detection of antibodies to Taenia solium, compared to serological diagnosis of neurocysticercosis (NCC) by LLGP-EITB (electro-immunotransfer blot assay using lentil-lectin purified glycoprotein antigens).

METHODS

Archive serum samples from patients with viable NCC (n = 45) or resolved, calcified NCC (n = 45), as well as sera from patients with other cestode parasites (hymenolepiasis, n = 45 and cystic hydatid disease, n = 45), were evaluated for cysticercosis antibody detection using two ELISA kits, Novalisa^® and Ridascreen^® . All NCC samples had previously tested positive, and all samples from heterologous infections were negative on LLGP-EITB for cysticercosis. Positive rates were calculated by kit and sample group and compared between the two kits.

RESULTS

Compared to LLGP-EITB, the sensitivity of both ELISA assays to detect specific antibodies in patients with viable NCC was low (44.4% and 22.2%), and for calcified NCC, it was only 6.7% and 4.5%. Sera from patients with cystic hydatid disease were highly cross-reactive in both ELISA assays (38/45, 84.4%; and 25/45, 55.6%). Sera from patients with hymenolepiasis cross-reacted in five cases in one of the assays (11.1%) and in only one sample with the second assay (2.2%).

CONCLUSIONS

The performance of Novalisa^® and Ridascreen^® was poor. Antibody ELISA detection cannot be recommended for the diagnosis of neurocysticercosis.