30th Annual Meeting of the German Society for Parasitology

Prof

Prof.

prof

Ultrasound assessment for hepatosplenic schistosomiasis in a highly endemic area of Madagascar: assessing the needs to call for actions

Abstract text Introduction Ultrasound (US) is crucial for the assessment of hepatosplenic schistosomiasis morbidity (HSS), although it is still poorly implemented in endemic countries, such as Madagascar. HSS is therefore mostly detected with complications (i.e., variceal bleeding, ascites) when praziquantel treatment is not effective, while some regression has been shown in lower degrees of periportal fibrosis. Objectives The overall objective is to describe US patterns and clinical presentation among patients with hepatosplenic schistosomiasis in a highly endemic area of Madagascar in order to advocate for the need of US implementation in Madagascar for both early detection and morbidity control of chronic schistosomiasis. Materials &amp; methods In a descriptive design we aim at recruiting 60 patients among all adult patients attending primary health care, pre-screened using urine based rapid diagnostic test regardless symptom presentation. Recruitment is currently ongoing. Morbidity is assessed following WHO guidelines for image pattern (IP) classification: no fibrosis (A), borderline aspect/ incipient portal fibrosis (B) (both no fibrosis group), moderate peripheral fibrosis (C), moderate central fibrosis (D) (moderate fibrosis group), and severe fibrosis (Dc, E, Ec,-F). Bleeding risk (BR) is assessed with SMS score using IP classification and portal vein quotient. Those presenting an SMS score &gt; 2 undergo EGDS and additional lab tests for further management. All patients are tested for chronic viral hepatitis, HIV antibodies, transaminases, blood count, albumin and creatinine. Praziquantel 40 mg/kg is administered once or for three days based on BR. US classification will be validated by two external experienced sonographers through imaging evaluations. Results Up to December 2022, eight patients (six women, age range 21-73 years, no viral infections) underwent US evaluation, with the following results: three severe forms (one Dc pattern, two F patterns, one of them with portal thrombosis), four moderate fibrosis (three C pattern, one D pattern) and one patient with no fibrosis. With the exception of one patient with severe fibrosis, none of them referred previous history of gastric bleeding, nor severe symptoms. Conclusion Our preliminary results show advanced fibrosis in patients without severe symptoms, supporting the need for early identification of HSS, for which US evaluation remains the first diagnostic tool.

Clinical Parasitology

One Health/NTD/Zoonoses

Talk

Prevalence of schistosomiasis and risk assessment among farmers in rural Madagascar: a cross-sectional study

Abstract text Introduction: Schistosomiasis is a parasitic disease of poverty spread by freshwater snails. Humans become infected through contact with contaminated freshwater. Therefore, occupational activities such as rice cultivation are believed to be a risk factor due to long and regular contact with contaminated water. It is to be noted that 70 percent of Madagascar's population is engaged in agriculture, mainly rice cultivation. Objectives: The present study aims to investigate the prevalence of schistosomiasis and its risk factors in rural Madagascar. Patients &amp; Methods: A cross-sectional study was conducted in 44 villages in the Vatomandry District. 1204 households were randomly selected based on their accessibility and agricultural profile, with a maximum of 5 participants per household. A total of 5199 participants were included meeting following inclusion criteria: voluntary consent, age over 5 years, no fever or Covid vaccination in the last 2 weeks, and no pregnancy. Door-to-door surveying was used to obtain sociodemographic background and dietary behaviour data based on the "UN Guidelines for Measuring Household and Individual Dietary Diversity". 5196 urine and 995 blood samples were collected for Schistosome infection analysis by means of urine based rapid diagnostic tests (RDT) and PCR. Results: A total of 1204 households with a median household size of 5 members (IQR=5-6) were surveyed. Among participants (n=5199), 56.1% were female. The mean age was 27 years (IQR=15-44), with 29.8% under 18. 58.1% of the total sample tested positive for schistosomiasis by RDT. 45.5% of adults work in agriculture. 58.5% of women and 57.6% of men tested positive. 45.4% of those under 18 tested positive, whereas 63.5% of adults did. Among adults who reported being farmers, 73.4% tested positive, 56.1% of non-farmers, and 43.5% of unemployed. 14.2% reported having been treated against schistosomiasis in the past, of whom 74.2% reported having been treated more than 12 months ago. Conclusion: Our preliminary data show that a high proportion of the population tested positive by RDT for schistosomiasis. The highest proportion of individuals testing positive was among farmers, who were also by far the largest occupational group. The positive rate among men and women was almost identical. Additional analysis is underway to further identify the most common species and risk factors for infection. This study will help improve preventive measures to control schistosomiasis.

Parasite-Host Interaction

Red fox as a reservoir of Cryptosporidium spp. and Giardia intestinalis in urban and natural areas

Abstract text Introduction: Red fox (Vulpes vulpes) is a major host for various intestinal parasites, however its role in spreading protists from the genera Cryptosporidium and Giardia is poorly understood, especially in urban environment. Objectives: Main aim of presented study was to compare prevalence of Cryptosporidium spp. and Giardia intestinalis infection in foxes from natural habitats and Warsaw parks. Materials &amp; methods: fecal samples obtained from 88 foxes (44 obtained during the hunting season 2016-2018 and 44 from Warsaw parks) were screened for Cryptosporidium spp. and G. intestinalis presence. For the detection of both intestinal parasites, the commercial immunofluorescent assay MeriFluor Cryptosporidium/Giardia was used. For Cryptosporidium detection modified Ziehl-Neelsen (ZN) staining of faecal smears and PCR amplification and sequencing of 18S rDNA and 60kDa glycoprotein gene (GP60) were used. For Giardia detection, PCR amplification and sequencing of the glutamate dehydrogenase (gdh) and the SSU-rRNA genes were conducted. Results: Our results showed differences between prevalence of Giardia and Cryptosporidium among foxes from natural and urban areas. There species of Cryptosporidium (C. hominis, C. parvum, C. canis) and Cryptosporidium sp. rodent genotype were identified in foxes. Prevalence of G. intestinalis was much lower than prevalence of Cryptosporidium spp. Conclusion: The obtained results expand the knowledge on zoonotic reservoir of Cryptosporidium and Giardia in two environments, which might help to determine public health threat associated with these protists. Acknowledgements: The study was financially supported by National Science Centre (NCN) Preludium grant no 2019/35/N/NZ7/01772 (DDS)

Wildlife Parasites

Prof., Dr.

Development and testing of new multi-locus sequence typing procedures for potentially zoonotic Giardia duodenalis genotypes

Abstract text Introduction Giardia duodenalis represents a species complex of 8 genetically distinguishable assemblages (A-H) with distinct host preferences. The two assemblages A and B are relevant to humans and are also found in a broad range of various mammals. Adequate procedures for molecular typing are only insufficiently developed to address epidemiological questions. Typing schemes require improvement of new marker genes allowing higher typing resolution, and need to account for allelic sequence heterozygocity (ASH) that can be a consequence of the tetraploid nature of the parasite or possible mixed infections. Objectives The aim was to test or develop new multi-locus sequence typing (MLST) procedures for assemblage A and B, respectively, as separate approaches are necessary for both assemblages. Materials &amp; methods For assemblage B, based on newly generated genomes we developed a new MLST scheme comprising 7 genomic marker sequences. Nested PCR protocols were designed and the new procedure was evaluated on &gt; 80 assemblage B isolates from various origins. For assemblage A, a recently published MLST procedure based on 6 marker genes was evaluated using &gt; 70 human and animal derived isolates. Results The new assemblage B MLST scheme confirmed ASH as a hallmark of assemblage B, which occurred in approximately 70% of the isolates and further revealed a subpopulation of assemblage B parasites exhibiting very low to no ASH. Sequence analysis showed that these subpopulations clustered separately. Strikingly, sequences of isolates from an assemblage B outbreak clearly formed a sub-cluster within the high ASH cluster with significantly lower inter se SNP variation compared to non-outbreak high ASH cluster isolates. The MLST scheme for assemblage A confirmed largely the lack of ASH in this assemblage and showed that sub-assemblage AII comprises only isolates from humans. All isolates from animals and a few from humans belonged to sub-assemblage AI. The discriminatory power within sub-assemblage AII was sufficient to group isolates from two separate outbreaks as distinct MLSTs. Conclusion Different typing protocols for assemblage A and B are necessary to retrieve informative MLST data for epidemiological purposes. The evaluation of relatedness of isolates based on SNPs depends on their respective subpopulation assignments. Both protocols will help to foster the generation of meaningful typing data much needed for future epidemiological studies.

Molecular Parasitology

Prof., Dr

Schistosoma infection and risk factors among schoolchildren in the rural area of the Democratic Republic of the Congo

Abstract text Introduction: Schistosomiasis (SCH) remains a major public health problem in the Democratic Republic of the Congo (DRC), especially in the rural community where environmental conditions increase the risk. The primary SCH control intervention strategy in the country is preventive chemotherapy with Praziquantel in all schoolchildren. This strategy was implemented in some endemic areas of the DRC but in other areas, there is a need of more scientific evidence on the burden of SCH for decision-making to optimize SCH control. The study aims to document the Schistosoma infection among schoolchildren in rural Health Area. Methodology: A cross-sectional study was carried out from June to August 2021 on schoolchildren in the rural community of Kisangi in the South-West of the DRC. The helminth infection was assessed using duplicate Kato-Katz thick smears for stool and a standard filtration technique for urine. A ﬁnger prick blood sample was collected and to assess for malaria infection and hemoglobin (Hb) level. Socio-demographic data and risk factors were assess using a semi-structured questionnaire. Results: Out of 480 schoolchildren aged 5 to 14 years enrolled in the study, 268 (55.8%; 51.4-60.2) had Schistosoma infection. Infection with S. haematobium, S. mansoni, and both infections were detected in 197 (41%; 36.6-45.5), 103 (36.3%; 31.9-40.6), and 103 (38.4%; 32.5-44.3) schoolchildren, respectively. The overall prevalence of malaria infection, anemia, and malnutrition were 16.9% (13.5-20.2), 49.4% (44.9-53.9), and 37.5% (33.2-41.8), respectively. Mean Hb level of all participants was 11.6 g/dl ±1.5. On multivariate regression analysis, Schistosoma infection was signiﬁcantly associated with age between 9-14 years (aOR. 2.3; p&lt;0.001), and anemia (aOR. 3.4; p&lt;0.001). However, malaria infection (aOR. 0.5; p=0.016) was a protective Schistosoma infection factor. Conclusion: Our findings indicate the hyper-endemic status of schistosomiasis associated with anemia among schoolchildren. There is a need for specific control intervention including prevention chemotherapy and supplementation in micronutrients to avoid anemia among schoolchildren.

Session XVIII
One Health/ NTD 1

Appointment

Chairs

Programme

Session XVIIIOne Health/ NTD 1

Appointment

Chairs

Programme

Session XVIII
One Health/ NTD 1