Welcome to the ICOPA 2022 Online Program

Introduction

Taenia solium cysticercosis/taeniosis (TSCT) is a zoonotic disease of human and pigs. There is perceived inefficient diagnosis of T. solium taeniosis and cysticercosis in low-income countries, including Tanzania. This study was aimed at identifying gaps in TSCT diagnosis and knowledge of officers in charge (OsIC) of primary healthcare facilities (PHFs) and meat inspectors (MIs) on various aspects of TSCT. Identified gaps will be addressed for effective disease control in Tanzania.

Methods

A cross sectional study was done between January and April 2020. We interviewed 152 OsIC of PHFs and 108 MIs using a structured questionnaire and 33 medical and veterinary officers from level one healthcare facilities and district livestock offices, respectively, in Babati, Mbulu, Kongwa, Mbinga and Nyasa districts up to their respective ministries using key informant interviews.

Results

Quantitative data revealed inadequate microscopic diagnostic facilities (54.6%) and personnel (100%) for taeniosis diagnosis in PHFs (n=152). Approximately, 81.2% of MIs compared to only 42.1% of OsIC of PHFs scored above average regarding T. solium cysticerci knowledge. Nevertheless, 61.2% of OsIC of PHFs compared to only 42.6% of MIs scored above average regarding the adult T. solium tapeworm knowledge. Likewise, qualitative data revealed inadequate advanced diagnostic facilities (neuroimaging) and trained personnel for TSCT diagnosis with a focus on neurocysticercosis in tertiary healthcare facilities. Inadequate MIs, slaughter slabs and resource facilitation hindered porcine cysticercosis diagnosis.

Conclusions

A One Health approach is needed to improve TSCT diagnostic capacity and knowledge among OsIC of PHFs and MIs which is still low in both medical and veterinary sectors.

Introduction

Echinococcus granulosus is the causative agent of cystic echinococcosis. Diagnosis is usually achieved using computerized imaging technologies, complemented by serological analyses. However, the latter have serious limitations in terms of specificity and, to a lesser extent, sensitivity. Even though Echinococcus infection induces a strong IgE response in infected hosts, including humans, this isotype is currently underexploited by current serological diagnostic techniques.

Methods

Several E. granulosus antigens known or predicted to be targeted by an IgE response were recombinantly expressed using a high yield HEK293-6E system and purified from serum-free media using IMAC. The humanized IgE reporters RS-ATL8 (luciferase) or NPY-mRFP (fluorescence) were sensitized with sera of healthy donors, individuals with confirmed echinococcosis, or other parasitic worm infections. After overnight sensitization and subsequent washes, the sensitized cells were stimulated with the candidate diagnostic antigens. Activation was measured using OneGlo-Luciferase substrate (RS-ATL8 cells) 3.5 hours post stimulation, or the release of NPY-mRFP fusion protein measured in supernatants 45 minutes post stimulation.

Results

Our data with raw cyst fluid as antigen demonstrate feasibility of IgE-based diagnosis of cystic echinococcosis. Cyclophilin and EF-1β, but not EF-1δ or EG95 activated the IgE reporter systems. The novel allergen G2 showed strong specific signals with echinococcosis sera and no cross-reactivity with strongyloidiasis, schistosomiasis, or other infections, but to some extent with filarial infections.

Conclusions

Our findings suggest that using IgE for diagnosis of E. granulosus infection is a feasible and promising proposition.

Introduction

Alveolar echinococcosis (AE) is a rare but severe zoonosis due to the cestode Echinococcus multilocularis (Em). Molecular diagnosis and study of its genetic diversity are usually based on a few mitochondrial genes and-or on the analysis of the EmsB microsatellite. This study aimed to analyze the genetic diversity of the full genome of the Em mitochondria (13,737 bp) and to compare it to those of other Echinococcus species.

Methods

DNA of Em was extracted from 30 human samples. Seven pairs of primers were designed and three multiplex PCR were developed to amplify the entire Em mitochondrial genome. Sequencing was performed with Illumina technology (P2M, Paris, France). Trimmed reads were mapped to the reference genome (GB: NC_000928.2). Sequences were intra-specifically aligned first and then with other Echinococcus species. Em haplotypes were determined on the one hand from mutations found in the whole mitochondrial genome and on the other hand from mutations focused on the concatenated sequences of the cob, cox1 and nad2 genes.

Results

From the 30 AE patients, 14 haplotypes have been identified, 13 being European and one closer to Asian haplotype. The European haplotypes differed by 30 polymorphic sites. Two hypervariable non-coding regions were identified following inter-species alignment.

Conclusions

From our study, a larger number of Em haplotypes was described. Analysis of hypervariable intergenic regions, flanked by conserved sequences common to Echinococcus species, may allow species identification.

Introduction

Although the food-borne infection route is considered relevant from an international public health prospective, only few and heterogeneous data are currently available on the transmission pathways of Echinococcus multilocularis (Em) and Echinococcus granulosus sensu lato (Eg sl) to humans. In the context of MEME project, this study aims to document the contamination of lettuces produced in non-intensive systems by eggs of Em, Eg sl and other Taenidae species.

Methods

Specific qPCRs were used to test pellets which were obtained after washing and sieving of 1,095 samples of lettuces collected in 2021 from private kitchen gardens, as well as from local markets and supermarkets in 10 European countries, Tunisia and Pakistan; all endemic for Em and/or Eg sl.

Results

The limit of detection for Em was established at 3 eggs per 300g of lettuce (50% limit of detection for 1 egg). Preliminary results based on the analysis of 771 samples indicate that 1.1% of the lettuces were positive for Em and 0.9% were positive for Hydatigera spp.

Conclusions

Although the viability of the eggs remains uncertain, the detection of Em and Hydatigera DNA confirms the presence of taeniid eggs in the lettuce leaves and suggests that their consumption can be a potential source of infection. Based on these data, new studies are needed to assess the viability of eggs and the associated zoonotic risk. In addition, a European multicentre study from MEME project on berries is planned using the same approach.

Introduction

Repeated rounds of intensive interventions have demonstrated to achieve elimination of Taenia solium transmission in areas where the parasite is highly endemic. To sustain elimination long-term efforts need to be made. A “ring strategy” that consists of targeted pig and human anthelmintic treatment in a ring around a positive case has been developed showing promising results in Peru.

The aims of this study were to implement the ring strategy in Zambia, assess its feasibility and demonstrate proof of concept.

Methods

The study was conducted in a community in the Eastern Province of Zambia where T. solium elimination had been achieved. Samplings were conducted on all eligible pigs and humans at 4- to 6-monthly intervals, followed by the implementation of the ring strategy. This implied that whenever a pig was found positive for porcine cysticercosis during a follow up sampling, every human and pig residing in a radius of 50-meters of the infected animal would be treated. Whenever no pigs were positive, the results of the human stool analyses were used to create the 50-meter rings.

Results

From June 2018 to October 2019, four follow up samplings were conducted. On average 558 human stool samples per sampling time point were analyzed representing half of the total population living in the study area. In the pig population, on average 91% of all eligible pigs were sampled. Three out of four ring treatments were based on positive pig samples. During ring treatments, between 89% and 100% of the human and pig population, eligible for treatment, were treated.

Conclusions

The results suggest that a ring strategy could be considered to sustain T. solium elimination in Zambia. However, it needs to be assessed over a larger timespan/area before recommendations to health authorities can be given.

Introduction

The larval stage of Echinococcus multilocularis is responsible for the zoonotic life-threatening disease alveolar echinococcosis (AE). Early diagnosis is crucial as it allows for more effective, less invasive treatment strategies. Although a number of sensitive and specific serological diagnostic tools have been developed, early diagnosis has remained problematic. The aim of the current study was to explore potential new biomarker candidates for AE diagnosis by studying the secreted proteins of the larval stage of E. multilocularis in vitro and validating a subset of parasite proteins in gerbil (Meriones unguiculatus) sera.

Methods

Three isolates of E. multilocularis larval stage were cultivated in vitro and the supernatant collected, with vesicle fluid (VF) used as a control. Secreted proteins were analyzed using LC-MS/MS and characterized using label free quantification (LFQ). Serum samples were obtained from experimentally infected gerbils. Subset of proteins were chosen for validation in serum samples using the SureQuant targeted proteomics approach.

Results

In vitro results revealed the secretion of approximately 1200 parasite derived proteins. After filtering for proteins that were constantly secreted and higher abundant in the supernatant fraction than in VF, 22 proteins of interest were further chosen for validation in sera. Preliminary results of gerbil sera revealed the presence of 5 parasite derived proteins.

Conclusions

We provide a comprehensive identification of secreted E. multilocularis larval stage proteins in vitro and initial validation of a subset of proteins in gerbil sera. In the future, a subset of these proteins could potentially be further validated as novel diagnostic markers for helping to improve early diagnosis of AE.