Cystic echinococcosis in northern Tanzania: a pilot study in Maasai livestock-keeping communities

Tamarozzi, F. et al. (2022) Cystic echinococcosis in northern Tanzania: a pilot study in Maasai livestock-keeping communities. Parasites and Vectors, 15, 396. (doi: 10.1186/s13071-022-05518-x) (PMID:36307877) (PMCID:PMC9616617)

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Abstract

Background: There are close similarities between the life-cycles of Echinococcus granulosus sensu lato (E. granulosus s.l.) that causes cystic echinococcosis (CE) in humans and Taenia multiceps/Coenurus cerebralis that causes cerebral coenurosis in small ruminants. Recent evidence highlights that livestock in Maasai communities of northern Tanzania are suffering from increases in the prevalence of cerebral coenurosis, leading to concerns about a possible concurrent increased risk of human CE. The aim of this study was to estimate the prevalence of human abdominal CE and the prevalence and species/genotypes of E. granulosus s.l. in livestock in Maasai communities. Methods: Human CE was diagnosed by abdominal ultrasound on volunteers aged ≥ 7 years in five villages in the Longido and Ngorongoro Districts in northern Tanzania. Infection in ruminants was evaluated through inspection in local abattoirs, followed by molecular identification of one cyst per animal, with a priority for hepatic cysts, using PCR targeting of the cytochrome c oxidase I gene (COX1), followed by restriction fragment length polymorphism and multiplex PCR, and sequencing of non-E. granulosus s.l. samples. Results: Ultrasound was performed on 823 volunteers (n = 352 in two villages in Longido District, and n = 471 in three villages of Ngorongoro). Hepatic CE cases were diagnosed only in Ngorongoro (n = 6; 1.3%), of which three had active cysts. Village-level prevalence of CE ranged between 0 and 2.4%. Of the 697 ruminants inspected, 34.4% had parasitic cysts. Molecular identification was achieved for 140 of the 219 (63.9%) cysts sampled. E. granulosus s.l. and T. hydatigena/Cysticercus tenuicollis were identified in 51.4% and 48.6%, respectively, of livestock cysts. E. granulosus s.l. was identified in livestock from both Longido (35.3% of 116 genotyped cysts) and Ngorongoro (91.2% of 34 genotyped cysts). Of the total of 72 E. granuslosus s.l. cysts identified in livestock, 87.5% were E. granulosus sensu stricto (G1–G3 genotypes), 9.7% were E. ortleppi (G5) and one cyst was E. canadensis (G6–10). The three active human cysts, which were removed surgically, were G1–G3 genotypes. Conclusions: Multiple species/genotypes of E. granulosus s.l. are circulating in Maasai communities of northern Tanzania. Human CE was detected in villages of Ngorongoro District and a high prevalence of echinococcal cysts was observed in livestock in both districts. More precise estimation of the prevalence in this area and a better understanding of the specific risk factors for CE among Maasai communities in northern Tanzania is needed. Interventions targeting transmission routes common to both E. granulosus s.l. and T. multiceps would have dual benefits for preventing both human and livestock disease.

Item Type:Articles
Additional Information:Funding: This project was funded by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Research Grant 2019 (to FT) and supported by the Italian Ministry of Health “Fondi Ricerca Corrente”–L2 (to IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy). The molecular analysis was supported by funding from the European Union Horizon 2020 Research and Innovation Programme grant agreement N773830: One Health European Joint Programme, Project “MEME” (https://onehealthejp.eu/jrp-meme/) (to AC). SC and WdG were supported by funding from the Biotechnology and Biological Sciences Research Council (BB/R020027/1 and BB/S013857/1).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:De Glanville, Dr William and Cleaveland, Professor Sarah and MMBAGA, Professor Blandina Theoph and Tamarozzi, Dr Francesca
Authors: Tamarozzi, F., Kibona, T., de Glanville, W. A., Mappi, T., Adonikamu, E., Salewi, A., Misso, K., Maro, V., Casulli, A., Santoro, A., Santolamazza, F., Mmbaga, B. T., and Cleaveland, S.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > Health Economics and Health Technology Assessment
College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > Public Health
Journal Name:Parasites and Vectors
Publisher:BioMed Central
ISSN:1756-3305
ISSN (Online):1756-3305
Copyright Holders:Copyright © 2022 The Authors
First Published:First published in Parasites and Vectors 15: 396
Publisher Policy:Reproduced under a Creative Commons license
Data DOI:10.5525/gla.researchdata.1299

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
302408Sustainable Interventions for an Emerging Livestock Disease Problem in East AfricaSarah CleavelandBiotechnology and Biological Sciences Research Council (BBSRC)BB/R020027/1Institute of Biodiversity, Animal Health and Comparative Medicine
304761Operationalising One Health Interventions in Tanzania (OOHTZ)Sarah CleavelandBiotechnology and Biological Sciences Research Council (BBSRC)BB/S013857/1Institute of Biodiversity, Animal Health and Comparative Medicine