Bayesian modelling to estimate the test characteristics of coprology, coproantigen ELISA and a novel real-time PCR for the diagnosis of taeniasis

Clustering of Gastrointestinal Microorganisms in Human Stool Samples from Ghana

The study was conducted to identify cluster patterns of enteric microorganisms with potential etiological relevance for infectious gastroenteritis in stool samples of individuals from Ghana, which is a known high-endemicity setting for infectious gastroenteritis. These patterns were compared to previous observations with specimens from Colombian indigenous people in order to assess potentially stable clustering for temporally and spatially distinct populations from high-endemicity regions. By doing so, the study aimed to identify stable clusters as markers of microbial interaction with potential importance for etiological relevance assignment in cases of multiple enteric pathogen detections. Stool samples from 1569 Ghanaian individuals (875 from HIV patients, 30 from HIV-negative control adult patients, and 644 from children < 2 years of age) were assessed for enteric microorganisms by applying real-time PCR. As a result, nucleic acids of bacterial microorganisms were most frequently detected, followed by protozoa, microsporidia, and helminths. Interestingly, the cluster assessment confirmed interaction patterns known from the previous analysis with Colombian indigenous people, demonstrating a high likelihood of Blastocystis hominis for clustering with other microorganisms and a prominent, potentially mediating role of Dientamoeba fragilis for microbial interactions within the clusters. In conclusion, the assessment confirmed conserved clustering of enteric microorganisms with potential etiological relevance for human infectious gastroenteritis over geographically distinct high-endemicity settings. Furthermore, the composition of abundant microorganisms is more important than regional factors for the determination of the interplay of enteric microorganisms in the human gut. Thereby, some microbial pathogens and commensals seem more susceptible to a changing microbial composition in the human gut than others.

Epidemiology of intestinal helminthiasis with an emphasis on taeniasis in Chipata district of the Eastern province of Zambia

BACKGROUND

Intestinal helminth infections are among the most common infections worldwide and have a negative impact on the health, education, nutrition and economic development of affected populations. This study aimed to estimate the prevalence of intestinal helminthiasis, including T. solium taeniasis, using a large-scale community-based study in Chiparamba area of Chipata District in the Eastern province of Zambia.

METHODS/PRINCIPAL FINDINGS

A cross-sectional study was conducted between June 2019 and December 2022 in a rural community of 25 randomly selected villages known to be at risk for T. solium infection. Stool samples were examined for intestinal helminths using the formol-ether concentration technique and further tested for taeniasis by copro antigen-ELISA (copro Ag-ELISA). Descriptive statistical analyses were conducted, and associations between the disease prevalence of active infections and individual- and village-level variables were determined using the chi-square or Fisher's exact test. Predictors of an individual being positive for either taeniasis or other soil-transmitted helminths were determined using binary logistic regression. A total of 2762 stool samples were examined. One hundred ninety-five (7.1%) tested positive for at least one helminthic parasite on microscopy, with hookworm being the most frequent 84 (3.0%), followed by S. mansoni, 66 (2.4%). For taeniasis, 11 (0.4%) participants were positive for Taenia spp. microscopically, while 241 (8.7%) tested positive via copro Ag-ELISA. On bivariate analysis, male sex was significantly associated with the prevalence of intestinal parasites (p = 0.012) but not with that of taeniasis based on copro Ag-ELISA results. Village level differences were significant for infection with intestinal helminths as well as for taeniasis positivity on copro Ag-ELISA (p <0.001).

CONCLUSION

Intestinal helminths, including T. solium taeniasis, are prevalent in Chiparamba area of Chipata district in the eastern province of Zambia, supporting the clear need for further targeted public health interventions for surveillance and control.

Comparison of Kato-Katz, PCR and coproantigen for the diagnosis of Taenia solium taeniasis

Four methods were compared for the diagnosis of human taeniasis caused by Taenia solium. Fecal samples from persons living in a T. solium endemic region of Madagascar were examined for taeniid eggs by the Kato–Katz method. Subsequently, samples positive (n = 16) and negative (n = 200) for T. solium eggs were examined by (i) amplification of the fragment of small subunit of the mitochondrial ribosomal RNA (rrnS) gene using conventional polymerase chain reaction (PCR) and (ii) a nested PCR of a fragment of the T. solium Tso31 gene. Additionally, 12 egg-positive and all egg-negative samples were tested for coproantigen detection. A further 9 egg-positive fecal samples were examined using both PCRs. Of the 12 egg-positive samples tested by PCRs and coproantigen methods, 9 (75%) were positive by rrnS PCR, 3 (25%) using Tso31-nested PCR and 9 (75%) by coproantigen testing. None of the 200 egg-negative fecal samples was positive in either rrnS or Tso31-nested PCR. Twenty of the 25 egg-positive samples (80%) were positive in rrnS PCR, and DNA sequencing of PCR amplicons was obtained from 18 samples, all confirmed to be T. solium. Twelve of the 25 egg-positive samples (48%) were positive in the Tso31-nested PCR, all of which were also positive by rrnS PCR. It is suggested that species-specific diagnosis of T. solium taeniasis may be achieved by either coprological examination to detect eggs or coproantigen testing, followed by rrnS PCR and DNA sequencing to confirm the tapeworm species in egg-positive or coproantigen-positive samples.

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.

H, Krovvidi S, Chennuru S. Prevalence of taeniosis in pig farming community in Andhra Pradesh, India

Taeniosis is one of the neglected zoonoses in India. Facts on taeniosis, compared to cysticercosis are scanty in India. Hence, this study is aimed to determine the occurrence of taeniosis in human beings in Andhra Pradesh, India. A total of 1380 stool samples were collected from people associated with pig farming and or had the habit of pork eating in certain districts (n = 7) of Andhra Pradesh. Prevalence of human taeniosis was determined using microscopic examination of stool samples and proglottds. The overall prevalence of taeniosis was found to be 0.79%. Morphology of gravid segments revealed lower number of lateral branches indicating T. solium segments. Age and gender of human were not associated with the occurrence of taeniosis. The low prevalence of taeniosis in human indicates good hygiene and sanitation practices in humans, and awareness about the disease and its transmission. Further studies involving more sensitive techniques on stool and serum samples are warranted.

A rare case of human taeniasis caused by Taenia saginata with species undetermined cysticercosis

Taeniasis and cysticercosis, which are caused by Taenia saginata, Taenia solium and Taenia asiatica, are zoonotic parasitic infections with a significant disease burden worldwide. There is consensus amongst experts that T. saginata is a common tapeworm that causes taeniasis in humans as opposed to cysticercosis. This case study of a middle-aged Tibetan man conducted in 2021 challenges the prevailing notion that T. saginata exclusively causes taeniasis and not cysticercosis by documenting symptoms and laboratory studies related to both taeniasis and multiple cysticercosis. The patient's medical record with the symptoms of taeniasis and cysticercosis was reviewed, and the tapeworm's proglottids and cyst were identified from the patient by morphological evaluation, DNA amplification and sequencing. The patient frequently experienced severe headaches and vomiting. Both routine blood screenings and testing for antibodies against the most common parasites were normal. After anthelmintic treatment, an adult tapeworm was found in feces, and medical imaging examinations suggested multiple focal nodules in the brain and muscles of the patient. The morphological and molecular diagnosis of the proglottids revealed the Cestoda was T. saginata. Despite the challenges presented by the cyst's morphology, the molecular analysis suggested that it was most likely T. saginata. This case study suggests that T. saginata infection in humans has the potential to cause human cysticercosis. However, such a conclusion needs to be vetted by accurate genome-wide analysis in patients with T. saginata taeniasis associated with cysts. Such studies shall provide new insights into the pathogenicity of T. saginata.

Global variation in force-of-infection trends for human Taenia solium taeniasis/cysticercosis

Infection by Taenia solium poses a major burden across endemic countries. The World Health Organization (WHO) 2021–2030 Neglected Tropical Diseases roadmap has proposed that 30% of endemic countries achieve intensified T. solium control in hyperendemic areas by 2030. Understanding geographical variation in age-prevalence profiles and force-of-infection (FoI) estimates will inform intervention designs across settings. Human taeniasis (HTT) and human cysticercosis (HCC) age-prevalence data from 16 studies in Latin America, Africa, and Asia were extracted through a systematic review. Catalytic models, incorporating diagnostic performance uncertainty, were fitted to the data using Bayesian methods, to estimate rates of antibody (Ab)-seroconversion, infection acquisition and Ab-seroreversion or infection loss. HCC FoI and Ab-seroreversion rates were also estimated across 23 departments in Colombia from 28,100 individuals. Across settings, there was extensive variation in all-ages seroprevalence. Evidence for Ab-seroreversion or infection loss was found in most settings for both HTT and HCC and for HCC Ab-seroreversion in Colombia. The average duration until humans became Ab-seropositive/infected decreased as all-age (sero)prevalence increased. There was no clear relationship between the average duration humans remain Ab-seropositive and all-age seroprevalence. Marked geographical heterogeneity in T. solium transmission rates indicate the need for setting-specific intervention strategies to achieve the WHO goals.

Assessment of environmental contamination with soil-transmitted helminths life stages at school compounds, households and open markets in Jimma Town, Ethiopia

Background

It remains largely unknown where and how infections with soil-transmitted helminths (STHs; Ascaris, Trichuris, Necator and Ancylostoma) occur. We therefore aimed to identify possible sources of infection by assessing the environmental contamination in an STH-endemic area.

Methods

We first performed a series of laboratory experiments designed to optimize a soil straining-flotation method to detect and quantify Ascaris and Trichuris eggs in soil, and to validate the diagnostic performance of the optimized method when followed by microscopy and qPCR. In a second phase, we applied this method to assess the level of STH contamination in 399 environmental samples collected from 10 school compounds, 50 households and 9 open markets in Jimma Town (Ethiopia). Subsequently, we explored associations between the environmental contamination and both the corresponding STH epidemiology at the level of the schools and the household characteristics. Finally, we assessed the knowledge, attitude and practice (KAP) towards STHs in school children.

Principal findings

Our soil straining-flotation method has an analytical sensitivity of 50 eggs per 100 grams of soil and egg recovery rate of 36.0% (Ascaris) and 8.0% (Trichuris). The analysis of field samples with both microscopy and qPCR revealed the presence of 8 different helminth species of medical importance, including but not limited to the human STHs. There was a significant association between the environmental contamination and prevalence of any STH infections at the school level only. The KAP indicated a lack of knowledge and awareness of STHs.

Conclusions/Significance

Our optimized straining-flotation method has a moderate diagnostic performance and revealed that life stages of helminths are ubiquitous in the environment, which might be due to the poor sanitary facilities at both the schools and the households, and a poor level of KAP towards STHs. Further research is required to gain more insights into the contribution of these life stages to transmission.

The recent strategies to control the morbidity caused by intestinal worms have mainly been focusing on large scale deworming programs during which drugs are administered to at-risk populations. Although these large-scale deworming programs have been successful in reducing the disease burden, re-infection in the absence of other intervention measures is unavoidable. Although there is a consensus on how infections with intestinal worms are transmitted, it remains unclear where hot spots of infectious life stages can be found in endemic communities, which in turn impedes both the design and the validation of interventions that prevent (re-)infection. We optimized a laboratory method to detect life stages in soil samples and applied this method to examine soil contamination at school compounds, households and open markets in Jimma Town (Ethiopia). Finally, we assessed the household characteristics, and the knowledge, attitude, and practice towards intestinal worms among school children. Generally, our results indicated (i) a moderate performance of our laboratory method, (ii) the ubiquitous presence of life stages in the environment, (iii) a poor level of sanitary facilities at both the schools and the households and (iv) a poor level of knowledge, attitude and practices towards intestinal worms.

Evaluation of an Antibody Detecting Point of Care Test for Diagnosis of Taenia solium Cysticercosis in a Zambian Rural Community: A Prospective Diagnostic Accuracy Study

The lack of cheap, easy-to-use, rapid diagnostic tests has led to the development of several rapid diagnostic tests for cysticercosis. The new prototype two-strip, Taenia solium point of care test (TS POC) detects antibodies against taeniosis (TS POC T) and cysticercosis (TS POC CC). This study evaluated the diagnostic performance of the TS POC CC in the Sinda district in eastern Zambia. A sample of 1254 participants was recruited and tested with the TS POC. Out of the 1249 participants with a valid TS POC result, 177 (14%) tested positive while 1072 (86%) tested negative. All individuals with a positive TS POC and a subset of negative TS POC participants were selected for serum sampling, and were subjected to the recombinant glycoprotein T24H enzyme-linked immunoelectrotransfer blot (rT24H EITB) and the serum B60/158 (serum Ag) enzyme-linked immunosorbent assay (Ag ELISA). Performance characteristics were estimated using a Bayesian approach with probabilistic constraints. Based on 255 complete cases, the estimated sensitivity and specificity of the TS POC CC test were 35% (95% CI: 14–63%) and 87% (95% CI: 83–90%), respectively. The diagnostic performance needs to be improved, possibly by titrating antigen and other reagents’ concentration in the strip to produce a performance similar to existing cysticercosis tests such as the rT24H EITB.

A retrospective study of Taenia spp. in Cuban patients: what does molecular analysis tell us?

Taeniosis is a neglected disease, particularly in developing countries, and is caused by infection with the adult tapeworm of either Taenia solium, Taenia saginata, and Taenia asiatica. Of these, T. solium is of primary concern due to the potential for cysticercosis should T. solium eggs be ingested. In Cuba, all cases of taeniosis are assumed to be caused by T. saginata, although some cases of cysticercosis have been documented. It is therefore important to gain further insights regarding the species causing taeniosis in Cuba, especially as diagnostic records indicate an increasing incidence, with the highest number of cases reported in 2020. In this study, we analysed 37 Taenia-positive faecal samples (or proglottids isolated from faecal samples) from the period 2001 until 2020 from all regions of the country. Genomic DNA was extracted from the samples, which had been stored in 10% formalin, using the QIAamp Tissue Kit. Species identification was carried out by duplex real-time PCR targeting the mitochondrial DNA. All cases were found to be T. saginata, and sequence analysis of three isolates confirmed the identification of this species. Our data do not provide any evidence that T. solium currently occurs in Cuba. However, given the relatively low number of samples analysed here, that the parasite may be imported with visitors or travellers who have been in endemic countries, and that taeniosis has relatively mild symptoms and thus infected patients may not seek medical attention, we recommend species determination for all taeniosis cases reported in Cuba.

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The incidence of taeniosis cases in Cuba is rising, with 2020 being a peak year

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Although assumed to be Taenia saginata, this has not been confirmed

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We investigated 37 samples from 2001 until 2020 that had been stored in formalin

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Duplex real-time PCR indicated T. saginata; 3 cases were confirmed by sequencing

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.

A systematic review and meta-analysis on prevalence and distribution of Taenia and Echinococcus infections in Ethiopia

Background

Tapeworm infections are among the tropical neglected parasitic diseases endemically occurring in Ethiopia. This systematic review and meta-analysis aims at estimating the pooled prevalence and distribution of Taenia and Echinococcus infections in humans and animals from reports from Ethiopia.

Methods

The systematic search was conducted in four bibliographic databases (PubMed, Google Scholar, Africa Journal Online and Science Direct). Additional data were retrieved from grey literature. Studies that met the inclusion criteria were considered for the systematic review and meta-analysis. The meta-analysis was conducted using MetaXL add-in for Microsoft Excel. Heterogeneity and inconsistency were evaluated using Cochran’s Q and I² statistics, respectively.

Results

The study provides a country-based database of Taenia and Echinococcus infections consisting of 311 datasets from 201 publications which were mostly abattoir surveys; of these, 251 datasets were subjected to meta-analysis. Most of the studies were from Oromia (32.8%) followed by Amhara (22.9%) regional states. The pooled prevalence of cystic echinococcosis in intermediate and accidental hosts was calculated as 22% (95% CI 18–26%) and high study variability (Q = 24,420.65, I² = 100%, P = 0.000). Moreover, a pooled prevalence of Echinococcus infections in final hosts was calculated as 33% (95% CI 20–48%) and low study variability (Q = 17.24, I² = 65%, P = 0.001). Similarly, study subjects (human, cattle, sheep, goat and wolf) were infected by Taenia spp. with pooled prevalence of 3% (95% CI 2–4%) and moderate study variability (Q = 279.07, I² = 89, P = 0.000). Meanwhile, the pooled prevalence of Taenia hydatigena, T. ovis and T. multiceps infections in intermediate hosts were calculated as 38%, 14% and 5%, respectively. The random effect meta-analysis of bovine cysticercosis showed a pooled prevalence of 7% (95% CI 5–9%) and high study variability was of (Q = 4458.76; I² = 99%, P = 0.000). Significant differences in prevalence of Taenia and Echinococcus infections between study sites or different livestock origins have been reported.

Conclusion

The study evidenced a comprehensive dataset on the prevalence and distribution of Taenia and Echinococcus infections at different interfaces by regions and hosts and hence can aid in the design of more effective control strategies.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04925-w.

Human Taeniasis and Cysticercosis and Related Factors in Phu Tho Province, Northern Vietnam

Several factors presumed to facilitate the transmission of Taenia spp. were reported in Vietnam. We conducted a cross-sectional study taking questionnaires from 1,185 participants, and collecting 1,151 sera and 1,036 stool samples in northern Vietnam. Sera were examined for circulating antigens of Taenia solium cysticerci using ELISA, stools for Taenia eggs by Kato-Katz smear, and copro-antigens by ELISA. Ag-ELISA revealed 4.6% antigen positivity, indicating infection with viable cysticerci. Taenia eggs were detected in 1.5% of participants. Copro-antigens were found in 2.8% of participants. Eating raw meat and/or vegetables was significantly associated with the presence of copro-antigen (OR=8.6, 95% CI: 1.16–63.9, P=0.01). Considering the high taeniasis prevalence and the associated threat, public health attention should be given to treat the tapeworm carriers in the projected areas.

Diagnóstico molecular de parasitosis intestinales

Infections causes by parasites of the gastrointestinal tract are a global public health problem. In industrialised countries, their particular epidemiological (low general prevalence of enteroparasites), economic (high labour costs) and clinical characteristics (constant increase in the number of samples and diagnostic determinations to be performed) have led molecular techniques to progressively replace conventional microscopy as the first-line diagnostic method of these pathogens in modern clinical laboratories. PCR-based techniques, particularly those developed for the simultaneous detection of the various agents that can cause the same infectious disease (syndromic diagnosis), already represent a cost-effective option that allow process automisation, workflow optimisation, and comparison of results among different laboratories, and facilitate accreditation of diagnostic procedures. This review clearly and concisely discusses the current situation of the molecular diagnosis of the main species of intestinal parasites in humans, particularly the enteric protozoans causing diarrhoea (Cryptosporidium spp., Giardia duodenalis, Entamoeba histolytica), the most important members the Microsporidia phyla (Enterocytozoon bieneusi) and Stramenopiles phyla (Blastocystis sp.), as well as the helminths transmitted by soil (Ancylostoma spp., Ascaris lumbricoides, Necator americanus, Strongyloides stercoralis and Trichuris trichiura) and food (Anisakis spp., Clonorchis sinensis, Fasciola spp., Taenia solium, and Trichinella spiralis). Special attention is paid to the description of available techniques and formats, to their diagnostic benefits and the most widely used genetic markers for their detection, both in clinical laboratories and genotyping in referral and research centres.

Taenia solium taeniasis/cysticercosis: From parasite biology and immunology to diagnosis and control

Infection with the pork tapeworm (Taenia solium) is responsible for a substantial global burden of disease, not only restricted to its impact on human health, but also resulting in a considerable economic burden to smallholder pig farmers due to pig cysticercosis infection. The life-cycle, parasitology and immunology of T. solium are complex, involving pigs (the intermediate host, harbouring the larval metacestode stage), humans (the definitive host, harbouring the adult tapeworm, in addition to acting as accidental intermediate hosts) and the environment (the source of infection with eggs/proglottids). We review the parasitology, immunology, and epidemiology of the infection associated with each of the T. solium life-cycle stages, including the pre-adult/adult tapeworm responsible for human taeniasis; post-oncosphere and cysticercus associated with porcine and human cysticercosis, and the biological characteristics of eggs in the environment. We discuss the burden associated, in endemic settings, with neurocysticercosis (NCC) in humans, and the broader cross-sectoral economic impact associated both with NCC and porcine cysticercosis, the latter impacting food-value chains. Existing tools for diagnostics and control interventions that target different stages of the T. solium transmission cycle are reviewed and their limitations discussed. Currently, no national T. solium control programmes have been established in endemic areas, with further work required to identify optimal strategies according to epidemiological setting. There is increasing evidence suggesting that cross-sectoral interventions which target the parasite in both the human and pig host provide the most effective approaches for achieving control and ultimately elimination. We discuss future avenues for research on T. solium to support the attainment of the goals proposed in the revised World Health Organisation neglected tropical diseases roadmap for 2021-2030 adopted at the 73rd World Health Assembly in November 2020.

Differing Effects of Standard and Harsh Nucleic Acid Extraction Procedures on Diagnostic Helminth Real-Time PCRs Applied to Human Stool Samples

This study aimed to assess standard and harsher nucleic acid extraction schemes for diagnostic helminth real-time PCR approaches from stool samples. A standard procedure for nucleic acid extraction from stool and a procedure including bead-beating as well as proteinase K digestion were compared with group-, genus-, and species-specific real-time PCR assays targeting helminths and nonhelminth pathogens in human stool samples. From 25 different in-house and commercial helminth real-time PCR assays applied to 77 stool samples comprising 67 historic samples and 10 external quality assessment scheme samples positively tested for helminths, higher numbers of positive test results were observed after bead-beating-based nucleic acid extraction for 5/25 (20%) real-time PCR assays irrespective of specificity issues. Lower cycle threshold values were observed for one real-time PCR assay after the standard extraction scheme, and for four assays after the bead-beating-based scheme. Agreement between real-time PCR results after both nucleic acid extraction strategies according to Cohen’s kappa ranged from poor to almost perfect for the different assays. Varying agreement was observed in eight nonhelminth real-time PCR assays applied to 67 historic stool samples. The study indicates highly variable effects of harsh nucleic acid extraction approaches depending on the real-time PCR assay used.

A Novel, Highly Sensitive Quantitative Polymerase Chain Reaction Assay for the Diagnosis of Subarachnoid and Ventricular Neurocysticercosis and for Assessing Responses to Treatment

BACKGROUND

Treatment of subarachnoid neurocysticercosis (NCC) is complicated, and assays that can guide treatment are not widely available. The reproducibility and scalability of molecular-based biomarkers would be of great use.

METHODS

The Taenia solium genome was mined and primers and probes were designed to target repeats with the highest coverage; the most sensitive, specific, and efficient repeat (TsolR13) was selected for clinical testing. We tested 46 plasma samples and 36 cerebral spinal fluid (CSF) samples taken from patients with subarachnoid or ventricular disease using quantitative polymerase chain reaction (qPCR).

RESULTS

The analytic sensitivity of TsolR13 was 97.3% at 240 attograms (ag) of T. solium genomic DNA and 100% analytic specificity. The clinical sensitivity in detecting active subarachnoid or ventricular disease in symptomatic patients was 100% in CSF and 81.3% in plasma. The predictive ability to distinguish active from cured disease was better for CSF (94.4% of those cured had negative qPCR results) than for plasma (86.7% of those cured tested negative). Some subjects also had plasma DNA detectable intermittently for years after being cured. Overall, the test performance was equivalent to T. solium antigen detection.

CONCLUSIONS

A qPCR test for the detection of the highly repetitive Tsol13 sequence has been developed and shown to be highly sensitive and specific for NCC, but also useful as a test of cure in CSF and for the definitive diagnosis of NCC in plasma.

Impact of a 3-year mass drug administration pilot project for taeniasis control in Madagascar

Taenia solium is endemic in Madagascar and presents a significant burden on the population and the health system. The parasite cycles through humans who host the adult tapeworm, and pigs that host the larval stages. Accidental infection of humans may occur with the larval stages which encyst in the nervous central system causing neurocysticercosis, a major cause of seizure disorders and a public health problem. One of the interventions to facilitate the control of the disease is mass drug administration (MDA) of the human population with taeniacide. Here we describe a pilot project conducted in Antanifotsy district of Madagascar from 2015 to 2017 where three annual rounds of MDA (praziquantel, 10mg/Kg) were undertaken in 52 villages. Changes in the prevalence of taeniasis were assessed before, during and after the treatments. A total of 221,308 treatments were given to all eligible people above 5 years of age representing a 95% coverage of the targeted population. No major adverse effects were notified related to the implementation of the MDA. The prevalence of taeniasis was measured using Kato-Katz and copro-antigen techniques. Analyses undertaken combining the results of the Kato-Katz with copro-antigen, or using the Kato-Katz results alone, showed that there was a significant reduction in taeniasis 4 months after the last MDA, but 12 months later (16 months after the last MDA) the taeniasis prevalence had returned to its original levels. Results of the pilot project emphasize the need of a multi-sectorial One-Health approach for the sustained control of T. solium.

The parasite Taenia solium causes neurocysticercosis in humans in its larval stage and is the main cause of seizure disorders in poor communities that keep pigs (the intermediate host). Diagnosis and treatment of neurocysticercosis remains beyond the reach of the general population in Madagascar. Prevention is therefore the most suitable strategy for combating this disease. Mass drug administration (MDA) is used to treat communities for several parasitic diseases such as schistosomiasis. Infection with the T. solium tapeworm in people can be treated with MDA using praziquantel. Here, we conducted a pilot project in Madagascar, giving over 220,000 treatments to people in 52 villages once per year, for 3 consecutive years. The effects on taeniasis seemed to be encouraging when assessed 4 months after finishing the treatment, but 16 months later, the parasite’s prevalence had returned to its original level. MDA was effective in providing temporary control of taeniasis, but parasite transmission was not interrupted. With respect to T. solium, this highlights the need of incorporating other interventions such as vaccination and medication in pigs, improved pig husbandry and meat inspection to tackle the whole cycle of the parasite.

Clinical helminthiases in Thailand border regions show elevated prevalence levels using qPCR diagnostics combined with traditional microscopic methods

BACKGROUND

Under-regulated national borders in Southeast Asia represent potential regions for enhanced parasitic helminth transmission and present barriers to helminthiasis disease control.

METHODS

Three Thailand border regions close to Myanmar, Laos and Cambodia were surveyed for clinical parasitic helminth disease. In-field microscopy was performed on stools from 567 individuals. Sub-samples were transported to Bangkok for molecular analysis comprising three multiplex qPCR assays.

RESULTS

The overall helminth infection prevalence was 17.99% as assessed by Kato-Katz and 24.51% by qPCR. The combined prevalence of the two methods was 28.57%; the most predominant species detected were Opisthorchis viverrini (18.34%), hookworm (6.88%; Ancylostoma spp. and Necator americanus), Ascaris lumbricoides (2.29%) and Trichuris trichiura (1.76%).

CONCLUSIONS

These data demonstrate the value of molecular diagnostics for determining more precise prevalence levels of helminthiases in Southeast Asia. Availability of such accurate prevalence information will help guide future public health initiatives and highlights the need for more rigorous surveillance and timely intervention in these regions.

Identification of risk areas and practices for Taenia saginata taeniosis/cysticercosis in Ethiopia: a systematic review and meta-analysis

Background

Bovine cysticercosis (BCC) is an infection of cattle with the metacestode stage of Taenia saginata, the beef tapeworm, which causes taeniosis in humans. BCC is responsible for considerable economic losses in the meat sector worldwide. This systematic review and meta-analysis summarizes the prevalence, risk factors and treatment efforts made so far on T. saginata infections in Ethiopia, providing a detailed analysis of different factors influencing the varying prevalence estimates in Ethiopia to gain more insight into the occurrence and risk factors of T. saginata taeniosis and cysticercosis to date.

Methods

A systematic review and meta-analysis was conducted on data collected from published and grey literature accessed through an electronic database and manual search.

Results

The literature search resulted in 776 outputs of which 132 conformed to the predefined criteria. The average zonal prevalence of meat inspection-based BCC ranged from 2% in Buno-Bedele to 24.6% in Sidama zone. The pooled prevalence of BCC was influenced by the number of muscle/organs inspected, ranging from 3.4% (95% CI: 1.7–5.1%) using fewer predilection sites to 19.4% (95% CI: 13.3–25.4%) using inspection of a maximum number of predilection sites. None of the tested variables were significantly associated with BCC. Questionnaire-based taeniosis ranged between 19.0% in Halaba special woreda to 70.0% in Gedeo zone and stool test-based taeniosis varied from 0.6% in central Tigray to 10.7% in Gurage zone. Questionnaire-based prevalence of taeniosis was higher in people with a frequent raw beef consumption habit (pooled OR, pOR: 10.5, 95% CI: 6.0–17.9), adults (pOR: 2.5, 95% CI: 1.7–3.6), men (pOR: 2.8, 95% CI: 2.1–3.6), and Christians (pOR: 2.0, 95% CI: 1.4–2.8) compared to less frequent raw beef consumers, younger people, women and Muslims, respectively.

Conclusions

This review revealed a widespread but variable occurrence of BCC and taeniosis in Ethiopian regions and zones, urging for harmonized and enhanced detection for improved control of the parasite. Accurate prevalence estimates using more sensitive tests, detailed risk factor analysis, as well as data on financial losses are needed to develop effective control strategies for the Ethiopian epidemiologic condition.

Parasitic Infections in African Humans and Non-Human Primates

Different protozoa and metazoa have been detected in great apes, monkeys and humans with possible interspecies exchanges. Some are either nonpathogenic or their detrimental effects on the host are not yet known. Others lead to serious diseases that can even be fatal. Their survey remains of great importance for public health and animal conservation. Fecal samples from gorillas (Gorilla gorilla) and humans living in same area in the Republic of Congo, chimpanzees (Pan troglodytes) from Senegal and one other from the Republic of Congo, Guinea baboons (Papio papio) from Senegal, hamadryas baboons (Papio hamadryas) from Djibouti and Barbary macaques (Macaca sylvanus) from Algeria, were collected. DNA was extracted and screened using specific qPCR assays for the presence of a large number of helminths and protozoa. Positive samples were then amplified in standard PCRs and sequenced when possible. Overall, infection rate was 36.5% in all non-human primates (NHPs) and 31.6% in humans. Great apes were more often infected (63.6%) than monkeys (7.3%). At least twelve parasite species, including ten nematodes and two protozoa were discovered in NHPs and five species, including four nematodes and a protozoan in humans. The prevalences of Giarida lamblia, Necator americanus, Enterobius vermicularis, Strongyloides stercoralis were similar between gorillas and human community co-habiting the same forest ecosystem in the Republic of Congo. In addition, human specific Mansonella perstans (5.1%) and other Mansonella spp. (5.1%) detected in these gorillas suggest a possible cross-species exchange. Low prevalence (2%) of Ascaris lumbricoides, Enterobius vermicularis, Strongyloides stercoralis were observed in chimpanzees, as well as a high prevalence of Abbreviata caucasica (57.1%), which should be considered carefully as this parasite can affect other NHPs, animals and humans. The Barbary macaques were less infected (7.2%) and Oesophagostomum muntiacum was the main parasite detected (5.8%). Finally, we report the presence of Pelodera sp. and an environmental Nematoda DNAs in chimpanzee feces, Nematoda sp. and Bodo sp. in gorillas, as well as DNA of uncharacterized Nematoda in apes and humans, but with a relatively lower prevalence in humans. Prevalence of extraintestinal parasites remains underestimated since feces are not the suitable sampling methods. Using non-invasive sampling (feces) we provide important information on helminths and protozoa that can infect African NHPs and human communities living around them. Public health and animal conservation authorities need to be aware of these infections, as parasites detected in African NHPs could affect both human and other animals’ health.

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.

Comparison of commercial and in-house real-time PCR platforms for 15 parasites and microsporidia in human stool samples without a gold standard

INTRODUCTION

A test comparison of in-house and commercial real-time PCR (qPCR) kits for the detection of human parasites and microsporidia in stool samples was conducted without a gold standard. Three different commercial kits were included in the comparison, with a range of 3-15 different PCR targets, while 14 targets were covered by in-house testing, so not all 16 target pathogens were covered by all assays.

METHODS

Residual materials from nucleic acid extractions of stool samples with very high likelihood of being colonized or infected by at least one enteric parasite species or microsporidia were tested. In all, 500 DNA samples were analyzed, but due to limited sample volume, only 250 of the 500 samples were tested per assay. Each sample was assessed with the qPCR platforms being compared and cycle threshold (Ct) values were included in a descriptive comparison.

RESULTS

Depending on the assay applied, qPCR detected per 250 tested samples Giardia duodenalis (184-205), Blastocystis spp. (174-183), Trichuris trichiura (118-120), Ascaris lumbricoides (79-96), Necator americanus (78-106), Hymenolepis nana (40-42), Cryptosporidium spp. (27-36), Dientamoeba fragilis (26-28), Schistosoma spp. (13-23), Enterobius vermicularis (8-14), Entamoeba histolytica (7-16), Strongyloides stercoralis (6-38), Cyclospora spp. (6-13), Taenia spp. (1-4), microsporidia (1-5), and Ancylostoma spp. (1-2). Inter-assay agreement kappa was almost perfect (0.81-1) for Dientamoeba fragilis, Hymenolepis nana, Cryptosporidium spp., and Ascaris lumbricoides, substantial (0.61-0.8) for Necator americanus, Blastocystis spp., Ancylostoma spp., Giardia duodenalis, Schistosoma spp., Trichuris trichiura, and Enterobius vermicularis, moderate (0.41-0.6) for Entamoeba histolytica, fair (0.21-0.4) for microsporidia, slight (0-0.2) for Cyclospora spp. and Strongyloides stercoralis, and poor (<0) for Taenia spp.

CONCLUSIONS

Varying inter-assay agreement makes interpretation of microsporidia and parasite PCR in stool samples challenging. Intra-assay agreement had been controlled during the developing of the assays. Future studies, e.g., with optimized nucleic acid procedures and including microscopically characterized samples, are advisable.

Relationship between tracheobronchoscopic score and bronchoalveolar lavage red blood cell numbers in the diagnosis of exercise-induced pulmonary hemorrhage in horses

Background

Exercise‐induced pulmonary hemorrhage (EIPH) is diagnosed and its severity assessed by post‐exercise tracheobronchoscopy, and enumeration of bronchoalveolar lavage fluid red blood cells (BALFRBC). Minimal information is available regarding the relationship of tracheobronchoscopy score to BALFRBC number.

Objective

Evaluate the relationship between BALFRBC number and tracheobronchoscopy scores and determine their diagnostic sensitivities.

Animals

Nine sedentary horses, 21 fit Thoroughbreds, 129 Barrel Racers.

Methods

Normal BALFRBC number and the effect of bronchoalveolar lavage (BAL) on it were evaluated by performing 2 BALs 24 hours apart in sedentary horses. Tracheobronchoscopy followed by BAL was performed 247 times on 150 horses after treadmill, racetrack, or barrel racing exercise. Lastly, a BALFRBC diagnostic threshold number that optimized the geometric mean of the sensitivity and precision (F1‐score) was determined using Bayesian analysis.

Results

No increase in BALFRBC occurred after the second BAL (mean ± SD, 304 ± 173/μL). Tracheobronchoscopy scores ranged from 0 (n = 112) to 4 (n = 4) and BALFRBC ranged from 102 to 4605268/μL. Spearman correlation between tracheobronchoscopy score and BALFRBC was weak (P < .001; rs = 0.42) with large ranges of BALFRBC associated with each tracheobronchoscopy score. The highest F1‐score occurred for a BALFRBC threshold number = 992/μL. Seventy‐five tracheobronchoscopy scores equaled 0 although BALFRBC number was ≥992/μL. Sensitivity of tracheobronchoscopy for diagnosing EIPH was poor (0.59; 95% confidence intervals [CI], 0.49‐0.68), compared to BALFRBC number ≥992/μL (0.93; 95% CI, 0.88‐0.96).

Conclusions and Clinical Importance

False negatives are common with tracheobronchoscopy. Follow‐up determination of BALFRBC may be indicated for tracheobronchoscopy scores = 0 before EIPH can be ruled out.

Diagnostic test evaluation methodology: A systematic review of methods employed to evaluate diagnostic tests in the absence of gold standard - An update

OBJECTIVE

To systematically review methods developed and employed to evaluate the diagnostic accuracy of medical test when there is a missing or no gold standard.

STUDY DESIGN AND SETTINGS

Articles that proposed or applied any methods to evaluate the diagnostic accuracy of medical test(s) in the absence of gold standard were reviewed. The protocol for this review was registered in PROSPERO (CRD42018089349).

RESULTS

Identified methods were classified into four main groups: methods employed when there is a missing gold standard; correction methods (which make adjustment for an imperfect reference standard with known diagnostic accuracy measures); methods employed to evaluate a medical test using multiple imperfect reference standards; and other methods, like agreement studies, and a mixed group of alternative study designs. Fifty-one statistical methods were identified from the review that were developed to evaluate medical test(s) when the true disease status of some participants is unverified with the gold standard. Seven correction methods were identified and four methods were identified to evaluate medical test(s) using multiple imperfect reference standards. Flow-diagrams were developed to guide the selection of appropriate methods.

CONCLUSION

Various methods have been proposed to evaluate medical test(s) in the absence of a gold standard for some or all participants in a diagnostic accuracy study. These methods depend on the availability of the gold standard, its' application to the participants in the study and the availability of alternative reference standard(s). The clinical application of some of these methods, especially methods developed when there is missing gold standard is however limited. This may be due to the complexity of these methods and/or a disconnection between the fields of expertise of those who develop (e.g. mathematicians) and those who employ the methods (e.g. clinical researchers). This review aims to help close this gap with our classification and guidance tools.

Molecular characterization of the Taenia solium Tso31 antigen and homologous of other Taenia species from Peru

Several studies have been performed to determine specific antigens for the diagnosis of tapeworms. One of these antigens is Tso31, which is used to differentiate Taenia solium and Taenia saginata in human feces. The aim of the present work was the molecular characterization of this protein in different tapeworm specimens collected in Peru: T. omisa (n = 6), T. hydatigena (n = 7), T. taeniaeformis (n = 4), T. pisiformes (n = 1), T. multiceps (n = 7), and T. solium (n = 10). Total DNA was extracted from each proglottid using a commercial DNA kit for tissue. A nested PCR was used to amplify a fragment of the previously described oncosphere-specific protein Tso31 gene. The nested PCR products were analyzed by 1.5% agarose gel electrophoresis and visualized after ethidium bromide staining. All nested PCR-positive products were sequenced and their sequences were compared. Of all the tapeworms analyzed, only T. solium and T. multiceps amplified the Tso31 gene. All sequences were identical for each species. Our T. solium Tso31 showed 100% similarity when compared with published GenBank sequences. The difference between T. solium and T. multiceps Tso31 samples was 8.1%. In conclusion, our results show that the tsol31 gene is not exclusive to T. solium.

Epidemiology of Taenia saginata taeniosis/cysticercosis: a systematic review of the distribution in southern and eastern Africa

Background

The beef tapeworm, Taenia saginata, causing cysticercosis in bovines and taeniosis in humans, is thought to have a global distribution. In eastern and southern Africa, cattle production plays a crucial role in the economy, but a clear overview of the prevalence of T. saginata in the region is still lacking. This review aims to summarize existing knowledge on T. saginata taeniosis and bovine cysticercosis distribution in eastern and southern Africa.

Methods

A systematic review was conducted, that gathered published and grey literature, including OIE reports, concerning T. saginata taeniosis and bovine cysticercosis in eastern and southern Africa published between January 1st, 1990 and December 31st, 2017.

Results

A total of 1232 records were initially retrieved, with 78 full text articles retained for inclusion in the database. Unspecified taeniosis cases were reported for Angola, Ethiopia, Kenya, Madagascar, Malawi, South Africa, Tanzania, Uganda and Zambia, whereas T. saginata taeniosis cases were found for Ethiopia, Kenya, South Africa, Tanzania, Zambia and Zimbabwe. The prevalence of taeniosis ranged between 0.2–8.1% based on microscopy, and between 0.12–19.7% based on coproAg-ELISA. In Ethiopia, the percentage of tapeworm self-reporting was high (45.0–64.2%), and a substantial number of anthelmintic treatments were reported to be sold in towns. The presence of bovine cysticercosis was reported in all 27 countries/territories included in the study, except for Rwanda and Somalia, Comoros, Madagascar, Mauritius, Mayotte, Seychelles and Socotra. The prevalence of cysticercosis ranged between 0.02–26.3% based on meat inspection, and between 6.1–34.9% based on Ag-ELISA.

Conclusions

Although T. saginata has been reported in the majority of countries/territories of the study area, T. saginata taeniosis/cysticercosis remains a largely ignored condition, probably due to the absence of symptoms in cattle, the lack of data on its economic impact, and the fact that human taeniosis is considered a minor health problem. However, the occurrence of bovine cysticercosis is a clear sign of inadequate sanitation, insufficient meat inspection, and culinary habits that may favour transmission. Measures to reduce transmission of T. saginata are therefore warranted and the infection should be properly monitored.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3163-3) contains supplementary material, which is available to authorized users.

Epidemiology of Taenia saginata taeniosis/cysticercosis: a systematic review of the distribution in the Americas

BACKGROUND

The distribution of Taenia saginata in the Americas is unclear. Establishing the distribution, economic burden, and potentials for control of bovine cysticercosis is increasingly important due to the growing demand for beef. This paper aims to take the first step and reviews the recent distribution of T. saginata taeniosis and bovine cysticercosis on a national level within the Americas.

METHODS

We undertook a systematic review of published and grey literature for information on the occurrence, prevalence, and geographical distribution of bovine cysticercosis and human taeniosis in the 54 countries and territories of the Americas between January 1st, 1990 and December 31st, 2017. Data on bovine cysticercosis from OIE reports from 1994 to 2005 were also included.

RESULTS

We identified 66 papers from the Americas with data on the occurrence of taeniosis or bovine cysticercosis and an additional 19 OIE country reports on bovine cysticercosis. Taeniosis was reported from 13 countries, with nine of these countries reporting specifically T. saginata taeniosis, and four countries reporting non-species specific taeniosis. The reported prevalence of taeniosis ranged between 0.04-8.8%. Bovine cysticercosis was reported from 19 countries, nine identified through the literature search, and an additional 10 identified through the OIE country reports for notifiable diseases. The reported prevalence of bovine cysticercosis ranged between 0.1-19%. Disease occurrence was restricted to 21 countries within the Americas, the majority from the mainland, with the only island nations reporting either bovine cysticercosis or taeniosis being Cuba, Haiti, and the US Virgin Islands.

CONCLUSIONS

Taenia saginata is widely distributed across 21 of the 54 countries in the Americas, but insufficient epidemiological data are available to estimate the subnational spatial distribution, prevalence, incidence and intensity of infections. This needs to be addressed through active surveillance and disease detection programmes. Such programmes would improve the data quantity and quality, and may enable estimation of the economic burden due to bovine cysticercosis in the region in turn determining the requirement for and cost-effectiveness of control measures.

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.

Identification and control of sources of Taenia solium infection – the attempts to eradicate the parasite

Taenia solium is a parasite causing porcine cysticercosis and human taeniosis and cysticercosis, parasitic zoonoses with a serious public health and economic influence. It has been globally ranked as the top foodborne parasite by the Food and Agriculture Organisation of the United Nations (FAO) and the World Health Organisation (WHO). This parasite is transmitted mainly in countryside regions where animals are free roaming, having access to human faeces, and infected pork is widely available. More developed countries eliminated cysticercosis; nonetheless, there are insufficient data about the current endemicity status of T. solium, due to increased human migration from endemic areas. Formally submitted statistics on cysticercosis in pigs are extremely inadequate. This is the result of not reporting all cases of the disease by some countries and lack of molecular verification during identification of the parasite. There is a need to develop diagnostic tests with increased sensitivity and specificity. The purpose of the present review is to summarise current knowledge about diagnostic and control methods concerning T. solium infection. The article does not address the diagnostics of human cysticercosis, since there is a distinct medical field which should be discussed separately. The paper focuses mainly on identifying the sources of T. solium infection, presenting the methods to detect and control porcine cysticercosis and taeniosis in humans.

Identification and Control of Sources of Taenia Solium Infection - the Attempts To Eradicate the Parasite

Taenia solium is a parasite causing porcine cysticercosis and human taeniosis and cysticercosis, parasitic zoonoses with a serious public health and economic influence. It has been globally ranked as the top foodborne parasite by the Food and Agriculture Organisation of the United Nations (FAO) and the World Health Organisation (WHO). This parasite is transmitted mainly in countryside regions where animals are free roaming, having access to human faeces, and infected pork is widely available. More developed countries eliminated cysticercosis; nonetheless, there are insufficient data about the current endemicity status of T. solium, due to increased human migration from endemic areas. Formally submitted statistics on cysticercosis in pigs are extremely inadequate. This is the result of not reporting all cases of the disease by some countries and lack of molecular verification during identification of the parasite. There is a need to develop diagnostic tests with increased sensitivity and specificity. The purpose of the present review is to summarise current knowledge about diagnostic and control methods concerning T. solium infection. The article does not address the diagnostics of human cysticercosis, since there is a distinct medical field which should be discussed separately. The paper focuses mainly on identifying the sources of T. solium infection, presenting the methods to detect and control porcine cysticercosis and taeniosis in humans.

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.

Performance of Real-Time Polymerase Chain Reaction Assays for the Detection of 20 Gastrointestinal Parasites in Clinical Samples from Senegal

Gastrointestinal parasite infections represent one of the biggest public health problems in the world. Therefore, appropriate innovative tools are needed for assessing interventions to control these infections. This study aims to compare the performance of real-time polymerase chain reaction (PCR) assays to microscopic examination for detection of intestinal parasites. A direct microscopic examination and stool concentration was performed on 98 stool samples from patients attending Senegalese hospitals. Negative microscopic control samples were also collected in Nice and Marseille (France). Species-specific primers/probes were used to detect 20 common gastrointestinal protozoans and helminths. Positive frequency and the sensitivity of each real-time PCR assay were compared with conventional microscopic examination. Real-time PCR was positive in 72 of 98 samples (73.5%), whereas microscopic examination was positive in 37 (37.7%) samples (P < 0.001). The real-time PCR assays were more sensitive than microscopy, with 57.4% (31/54) versus 18.5% (10/54), respectively, in the detection of parasites in asymptomatic patients (P < 0.05). In terms of polyparasitism, there were more coinfections detected by real-time PCR assays compared with microscopic methods (25.5% versus 3.06%). In comparison to parasite prevalence on individual samples, the results showed a perfect agreement (100%) between the two techniques for seven species, whereas discrepancies were observed for the others (agreement percentage varying from 64.2% to 98.9%). Real-time PCR appeared to be superior to microscopic examination for the detection of parasites in stool samples. This assay will be useful in diagnostic laboratories and in the field for evaluating the efficacy of mass drug administration programs.

Comparison of a new multiplex real-time PCR with the Kato Katz thick smear and copro-antigen ELISA for the detection and differentiation of Taenia spp. in human stools

Background

Taenia solium, the cause of neurocysticercosis (NCC), has significant socioeconomic impacts on communities in developing countries. This disease, along with taeniasis is estimated to infect 2.5 to 5 million people globally. Control of T. solium NCC necessitates accurate diagnosis and treatment of T. solium taeniasis carriers. In areas where all three species of Taenia tapeworms (T. solium, Taenia saginata and Taenia asiatica) occur sympatrically, conventional microscope- and copro-antigen based diagnostic methods are unable to distinguish between these three Taenia species. Molecular diagnostic tools have been developed to overcome this limitation; however, conventional PCR-based techniques remain unsuitable for large-scale deployment in community-based surveys. Moreover, a real-time PCR (qPCR) for the discrimination of all three species of Taenia in human stool does not exist. This study describes the development and validation of a new triplex Taq-Man probe-based qPCR for the detection and discrimination of all three Taenia human tapeworms in human stools collected from communities in the Central Highlands of Vietnam. The diagnostic characteristics of the test are compared with conventional Kato Katz (KK) thick smear and copro-antigen ELISA (cAgELISA) method utilizing fecal samples from a community based cross-sectional study. Using this new multiplex real-time PCR we provide an estimate of the true prevalence of taeniasis in the source population for the community based cross-sectional study.

Methodology/Principal findings

Primers and TaqMan probes for the specific amplification of T. solium, T. saginata and T. asiatica were designed and successfully optimized to target the internal transcribed spacer I (ITS-1) gene of T. solium and the cytochrome oxidase subunit I (COX-1) gene of T. saginata and T. asiatica. The newly designed triplex qPCR (T3qPCR) was compared to KK and cAgELISA for the detection of Taenia eggs in stool samples collected from 342 individuals in Dak Lak province, Central Highlands of Vietnam. The overall apparent prevalence of taeniasis in Dak Lak province was 6.72% (95% confidence interval (CI) [3.94–9.50]) in which T. solium accounted for 1.17% (95% CI [0.37–3.17]), according to the T3qPCR. There was sympatric presence of T. solium, T. saginata and T. asiatica. The T3qPCR proved superior to KK and cAgELISA for the detection and differentiation of Taenia species in human feces. Diagnostic sensitivities of 0.94 (95% credible interval (CrI) [0.88–0.98]), 0.82 (95% CrI [0.58–0.95]) and 0.52 (95% CrI [0.07–0.94]), and diagnostic specificities of 0.98 (95% CrI [0.94–1.00]), 0.91 (95% CrI [0.85–0.96]) and 0.99 (95% CrI [0.96–1.00]) were estimated for the diagnosis of taeniasis for the T3qPCR, cAgELISA and KK thick smear in this study, respectively.

Conclusions

T3qPCR is not only superior to the KK thick smear and cAgELISA in terms of diagnostic sensitivity and specificity, but it also has the advantage of discriminating between species of Taenia eggs in stools. Application of this newly developed T3qPCR has identified the existence of all three human Taenia tapeworms in Dak Lak province and proves for the first time, the existence of T. asiatica in the Central Highlands and the south of Vietnam.

Human taeniid tapeworms comprise three species, Taenia solium, Taenia saginata and Taenia asiatica. Taeniasis is a meat-borne zoonosis transmitted by the consumption of cysticerci in raw or undercooked pork for T. solium and T. asiatica (liver) and in beef for T. saginata. Accidental ingestion of T. solium eggs by humans also results in the formation of cysticerci, often in the brain, referred to as neurocysticercosis (NCC). T. solium NCC is a significant cause of morbidity and mortality owing to epilepsy in many resource-poor communities. In animals, ingestion of eggs passed by humans results in organ and/or carcass condemnation and suboptimal economic outcomes for farmers. The accurate diagnosis of T. solium tapeworm carriers is essential to monitor the success of control programs. In areas where all three species of Taenia tapeworms occur together, conventional diagnostic methods are unable to distinguish between the different species of Taenia. In this study, we develop and apply a T3qPCR capable of detecting and discriminating all three-tapeworm species in stools in a rapid and high-throughput fashion, suitable for large-scale community surveys. The newly developed T3qPCR proved superior to previously developed immunodiagnostic and conventional microscopic-based tests in terms of diagnostic sensitivity, specificity and the ability to identify and distinguish human Taenia species. This qPCR assay facilitated the identification of T. asiatica tapeworms in the Central Highlands of Vietnam, for the first time.

Epidemiology of polyparasitism with Taenia solium, schistosomes and soil-transmitted helminths in the co-endemic village of Malanga, Democratic Republic of Congo

Helminth co-infections are common in sub-Saharan Africa. However, little is known about the distribution and determinants of co-infections with Taenia solium taeniasis/cysticercosis. Building on a previous community-based study on human cysticercosis in Malanga village, we investigated co-infections with Taenia solium, soil-transmitted helminths (STHs) and Schistosoma spp and associated risk factors in a random subsample of 330 participants. Real time PCR assays were used to detect DNA of soil-transmitted helminths (STHs), T. solium and Schistosoma in stool samples and Schistosoma DNA in urine samples. Serum samples were tested for T. solium cysticercosis using the B158/B60 monoclonal antibody-based antigen ELISA. Bivariate analysis and logistic regression were applied to assess associations of single and co-infections with common risk factors (age, sex, area, hygiene) as well as pair wise associations between helminth species. Overall, 240 (72.7%) participants were infected with at least one helminth species; 128 (38.8%) harbored at least two helminth species (16.1% with STHs-Schistosoma, 14.5% with STHs-T. solium taeniasis/cysticercosis and 8.2% with Schistosoma-T. solium taeniasis/cysticercosis co-infections). No significant associations were found between Schistosoma-T. solium taeniasis/cysticercosis co-infection and any of the risk factors studied. Males (OR=2 (95%CI=1.1-5), p=0.03) and open defecation behavior (OR=3.8 (95%CI=1.1-6.5), p=0.04) were associated with higher odds of STHs-T. solium taeniasis/cysticercosis co-infection. Village districts that were found at high risk of T. solium taeniasis/cysticercosis were also at high risk of co-infection with STHs and T. solium taeniasis/cysticercosis (OR=3.2 (95%CI=1.1-7.8), p=0.03). Significant pair-wise associations were found between T. solium cysticerci and Necator americanus (OR=2.2 (95%CI=1.2-3.8), p<0.01) as well as Strongyloides stercoralis (OR=2.7 (95%CI=1.1-6.5), p=0.02). These findings show that co-infections with T. solium are common in this polyparasitic community in DRC. Our results on risk factors of helminth co-infections and specific associations between helminths may contribute to a better integration of control within programmes that target more than one NTD.

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

Human cysticercosis (CC) is a parasitic zoonosis caused by the larval stage (cyst) of the Taenia solium. Cysts can establish in the human central nervous system (neurocysticercosis, NCC) and other organs and tissues; they also develop in pigs, the natural intermediate host. Human taeniosis may be caused by T. solium, Taenia saginata and Taenia asiatica tapeworms; these infections are usually asymptomatic, but show a significant relevance as they perpetuate the parasites’ life cycle, and, in the case of T. solium, they are the origin of (N)CC. In European Union (EU) member states and associated countries, the occurrence of autochthonous T. solium cases is debated, and imported cases have significantly increased lately; the status of T. asiatica has been never reported, whereas T. saginata is prevalent and causes an economic impact due to condemned carcasses. Based on their effects on the EU society, the specific diagnosis of these pathologies is relevant for their prevention and control. The aims of this study were to know the diagnostic tests used in European laboratories for human taeniosis/cysticercosis by means of a questionnaire, to determine potential gaps in their detection, and to obtain preliminary data on the number of diagnosed taeniosis/CC cases.

An integrated study of human and animal infectious disease in the Lake Victoria crescent small-holder crop-livestock production system, Kenya

BACKGROUND

The neglected zoonotic diseases (NZD) are an understudied group that are a major cause of illness throughout the developing world. In general, little is known about the prevalence and burden of NZDs in affected communities, particularly in relation to other infectious diseases with which they are often co-endemic. We describe the design and descriptive epidemiological outputs from an integrated study of human and animal zoonotic and non-zoonotic disease in a rural farming community in western Kenya.

METHODS

This cross-sectional survey involved 2113 people, their cattle (n = 983) and pigs (n = 91). People and animals were tested for infection or exposure to a wide range of zoonotic and non-zoonotic pathogens. Prevalence estimates, with adjustment for the complex study design, were derived. Evidence for spatial clustering in exposure or infection was identified using the spatial scan statistic.

RESULTS

There was a high prevalence of human parasitism in the community, particularly with hookworm (Ancylostoma duodenale or Necator americanus) (36.3% (95% CI 32.8-39.9)), Entamoeba histolytica/dispar (30.1% (95% CI 27.5-32.8)), and Plasmodium falciparum (29.4% (95% CI 26.8-32.0)). Human infection with Taenia spp. was also prevalent (19.7% (95% CI 16.7-22.7)), while exposure to other zoonotic pathogens was comparatively rarer (Brucella spp., 0.6% (95% CI 0.2-0.9); Coxiella burnetii, 2.2% (95% CI 1.5-2.9); Rift Valley fever, 0.5% (95% CI 0.2-0.8)). A low prevalence of exposure to Brucella spp. was observed in cattle (0.26% (95% CI 0-0.56). This was higher for Rift Valley fever virus (1.4% (95% CI 0.5-2.22)) and C. burnetii (10.0% (95% CI 7.7-12.2)). The prevalence of Taenia spp. cysticercosis was 53.5% (95% CI 48.7-58.3) in cattle and 17.2% (95% CI 9.1-25.3) in pigs. Mycobacterium bovis infection was found in 2.2% of cattle (95% CI 1.3-3.2), while the prevalence of infection with Mycobacterium spp. was 8.2% (95% CI 6.8-9.6) in people.

CONCLUSION

Zoonotic infections in people and animals occur in the context of a wide range of co-endemic pathogens in a rural community in western Kenya. The wide diversity of pathogens under study provides a unique opportunity to explore the distribution and determinants of infection in a multi-pathogen, multi-host system.

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.

A systematic review of taeniasis, cysticercosis and trichinellosis in Vietnam

Taeniasis, cysticercosis and trichinellosis have been ranked as the most important food-borne parasites of humans in terms of public health, socioeconomic and trade impact. Despite this, information on these food-borne zoonoses in Vietnam is scarce and fragmented, and many local reports remain inaccessible to the international research community. This study aims to conduct comprehensive literature searches to report on the incidence and estimate the true prevalence of taeniasis in humans and T. solium cysticercosis in humans and pigs in Vietnam utilizing Bayesian models; in addition, to report the incidence and the distribution of trichinellosis. A Bayesian approach was used to estimate the true prevalence of taeniasis and cysticercosis based on published diagnostic test characteristics used in each published cross-sectional survey. The utilization of coproscopic-based examination of Taenia eggs in stool, although highly specific for genus-level detection, has poor sensitivity and led to an underestimation of the prevalence of human taeniasis. Similarly, post-mortem-based surveys of T. solium cysticercosis in pigs also led to the underestimation of prevalence of porcine cysticercosis. On the other hand, the low specificity of immunodiagnostic methods, in particular Ab-ELISA, led to a likely overestimation of T. solium cysticercosis in humans. Due to the use of imperfect diagnosis tests combined with poor descriptions of sampling methods, our ability to draw solid conclusions from these data is limited. We estimate that the true prevalence of taeniasis and T. solium cysticercosis in rural ‘hotspots’, is as high as 13% for each, in humans. Taeniasis and T. solium cysticercosis occurs in 60 of the 63 provinces of Vietnam. Most of the information relating to the distribution and prevalence of porcine cysticercosis is limited to commercial abattoir surveys. In Vietnam, Taenia asiatica appears to be confined to the north where it occurs sympatrically with T. solium and Taenia saginata. The status of T. asiatica in Central and South Vietnam remains unascertained. To date, five outbreaks of trichinellosis have been reported in the north and northwest of Vietnam, affecting a total of 114 people and responsible for eight fatalities. In the same region, studies of free-roaming pigs showed evidence of high levels of exposure to Trichinella and, in cases where larvae were recovered, the species present were identified as Trichinella spiralis. Based on five studies, the main risk factors for pork-borne zoonoses in Vietnam include the consumption of undercooked/raw meat and vegetables and the use of night-soil for fertilization of local produce. This systematic review draws attention to the importance of these pork-borne zoonoses.

Geospatial and age-related patterns of Taenia solium taeniasis in the rural health zone of Kimpese, Democratic Republic of Congo

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We assessed patterns of taeniasis in 24 village communities of Kimpese health zone.

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Prevalence of taeniasis was very high and varied between households and villages.

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Children of five to ten years were the most infected age group.

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Taeniasis was not spatially correlated with porcine cysticercosis.

Background

Taenia solium infections are mostly endemic in less developed countries where poor hygiene conditions and free-range pig management favor their transmission. Knowledge on patterns of infections in both human and pig is crucial to design effective control strategies. The aim of this study was to assess the prevalence, risk factors and spatial distribution of taeniasis in a rural area of the Democratic Republic of Congo (DRC), in the prospect of upcoming control activities.

Methods

A cross-sectional study was conducted in 24 villages of the health zone of Kimpese, Bas Congo Province. Individual and household characteristics, including geographical coordinates were recorded. Stool samples were collected from willing participants and analyzed using the copro-antigen enzyme-linked immunosorbent assay (copro-Ag ELISA) for the detection of taeniasis. Blood samples were collected from pigs and analyzed using the B158/B60 monoclonal antibody-based antigen ELISA (sero-Ag ELISA) to detect porcine cysticercosis. Logistic regression and multilevel analysis were applied to identify risk factors. Global clustering and spatial correlation of taeniasis and porcine cysticercosis were assessed using K functions. Local clusters of both infections were identified using the Kulldorff’s scan statistic.

Results

A total of 4751 participants above 5 years of age (median: 23 years; IQR: 11–41) were included. The overall proportion of taeniasis positivity was 23.4% (95% CI: 22.2–24.6), ranging from 1 to 60% between villages, with a significant between-household variance of 2.43 (SE = 0.29, p < 0.05). Taeniasis was significantly associated with age (p < 0.05) and the highest positivity was found in the 5–10 years age group (27.0% (95% CI: 24.4–29.7)). Overall, 45.6% (95% CI: 40.2–51) of sampled pigs were sero-positive. The K functions revealed a significant overall clustering of human and pig infections but no spatial dependence between them. Two significant clusters of taeniasis (p<0.001; n = 276 and n = 9) and one cluster of porcine cysticercosis (p<0.001; n = 24) were found.

Conclusion

This study confirms high endemicity and geographical dispersal of taeniasis in the study area. The role of age in taeniasis patterns and significant spatial clusters of both taeniasis and porcine cysticercosis were evidenced, though no spatial correlation was found between human and pig infections. Urgent control activities are needed for this endemic area.

Effect of repeated mass drug administration with praziquantel and track and treat of taeniosis cases on the prevalence of taeniosis in Taenia solium endemic rural communities of Tanzania

This study evaluated the effect of mass drug administration (MDA) with praziquantel administered to school-aged children (SAC) combined with 'track and treat' of taeniosis cases in the general population on the copro-antigen (Ag) prevalence of taeniosis. The study was conducted in 14 villages in Mbozi and Mbeya district, Tanzania. SAC made up 34% of the population and received MDA with praziquantel (40mg/kg) in 2012 (both districts) and in 2013 (Mbozi only). Three cross-sectional population-based surveys were performed in 2012 (R0), 2013 (R1), and 2014 (R2). In each survey approximately 3000 study subjects of all ages were tested for taeniosis using copro-Ag-ELISA. In total 9064 people were tested and copro-Ag-ELISA positive cases were offered treatment 6-8 months after sampling. The copro-Ag prevalence of taeniosis was significantly higher (Χ²-test, p=0.007) in Mbozi (3.0%) at R0 compared to Mbeya (1.5%). Twelve months after MDA in both districts (R1), the copro-Ag prevalence had dropped significantly in both Mbozi (2.0%, p=0.024) and in Mbeya (0.3%, p=0.004), but the significant difference between the districts persisted (Χ²-test, p<0.001). Ten months after the second round of MDA in Mbozi and 22 month after the first MDA (R2), the copro-Ag prevalence had dropped significantly again in Mbozi (0.8%, p<0.001), but had slightly increased in Mbeya (0.5%, p=0.051), with no difference between the two districts (Χ²-test, p=0.51). The taeniosis cases tracked and treated between round R0 and R2 represented 9% of the projected total number of taeniosis cases within the study area, based on the copro-Ag prevalence and village population data. Among SAC in Mbozi, infection significantly decreased at R1 (p=0.004, OR 0.12, CI: 0.02-0.41) and R2 (p=0.001, OR 0.24, CI: 0.09-0.53) when comparing to R0. In Mbeya infection significant decreased at R1 (p=0.013, OR 0.14, CI: 0.02-0.55), but no difference was found for R2 (p=0. 089), when comparing to R0 among SAC. This study showed that school-based MDA with praziquantel in combination with 'track and treat' of taeniosis cases significantly reduced the copro-Ag prevalence of taeniosis, and that annual MDA was significantly better than single MDA. The persistence of taeniosis cases illustrates that a One Health approach must be emphasized for effective control.

Microbiological laboratory diagnostics of neglected zoonotic diseases (NZDs)

This review reports on laboratory diagnostic approaches for selected, highly pathogenic neglected zoonotic diseases, i.e. anthrax, bovine tuberculosis, brucellosis, echinococcosis, leishmaniasis, rabies, Taenia solium-associated diseases (neuro-/cysticercosis & taeniasis) and trypanosomiasis. Diagnostic options, including microscopy, culture, matrix-assisted laser-desorption-ionisation time-of-flight mass spectrometry, molecular approaches and serology are introduced. These procedures are critically discussed regarding their diagnostic reliability and state of evaluation. For rare diseases reliable evaluation data are scarce due to the rarity of samples. If bio-safety level 3 is required for cultural growth, but such high standards of laboratory infrastructure are not available, serological and molecular approaches from inactivated sample material might be alternatives. Multiple subsequent testing using various test platforms in a stepwise approach may improve sensitivity and specificity. Cheap and easy to use tests, usually called "rapid diagnostic tests" (RDTs) may impact disease control measures, but should not preclude developing countries from state of the art diagnostics.

Monitoring the outcomes of interventions against Taenia solium: options and suggestions

There is an increasing interest in reducing the incidence of human neurocysticercosis, caused by infection with the larval stage of Taenia solium. Several intervention trials are currently assessing various options for control of T. solium transmission. A critical aspect of these trials will be the evaluation of whether the interventions have been successful. However, there is no consensus about the most appropriate or valuable methods that should be used. Here, we undertake a critical assessment of the diagnostic tests which are currently available for human T. solium taeniasis and human and porcine cysticercosis, as well as their suitability for evaluation of intervention trial outcomes. Suggestions are made about which of the measures that are available for evaluation of T. solium interventions would be most suitable, and which methodologies are the most appropriate given currently available technologies. Suggestions are also made in relation to the most urgent research needs in order to address deficiencies in current diagnostic methods.

Molecular testing for clinical diagnosis and epidemiological investigations of intestinal parasitic infections

Over the past few decades, nucleic acid-based methods have been developed for the diagnosis of intestinal parasitic infections. Advantages of nucleic acid-based methods are numerous; typically, these include increased sensitivity and specificity and simpler standardization of diagnostic procedures. DNA samples can also be stored and used for genetic characterization and molecular typing, providing a valuable tool for surveys and surveillance studies. A variety of technologies have been applied, and some specific and general pitfalls and limitations have been identified. This review provides an overview of the multitude of methods that have been reported for the detection of intestinal parasites and offers some guidance in applying these methods in the clinical laboratory and in epidemiological studies.

Taenia solium Taeniasis and Cysticercosis in Southeast Asia

Human taeniasis/cysticercosis caused by the pork tapeworm Taenia solium has been identified as a potentially eradicable disease by the International Task Force for Disease Eradication of the World Health Organization. In southeast Asia, T. solium taeniasis/cysticercosis is considered one of the major neglected tropical diseases afflicting the region. In the last few decades, a considerable effort has been invested toward establishing the epidemiology and burden of disease in several southeast Asian countries. Moreover, further evidence is emerging as to understanding the dynamics of disease transmission and cultural, political, and socioeconomic factors influencing the success of control and eradication efforts within the region. However, despite major collaborations by several champion groups, advances have been slow and little remains known about the complete epidemiology of taeniasis/cysticercosis and the barriers to programmatic success. This review article aims to address the above issues with a further focus on the challenges to control and eradicate taeniasis/cysticercosis within the southeast Asia region.