Assessing the impact of intervention strategies against Taenia solium cysticercosis using the EPICYST transmission model.
The pork tapeworm, Taenia solium, and associated human infections, taeniasis, cysticercosis and neurocysticercosis, are serious public health problems, especially in developing countries. The World Health Organization (WHO) has set goals for having a validated strategy for control and elimination of T. solium taeniasis/cysticercosis by 2015 and interventions scaled-up in selected countries by 2020. Timely achievement of these internationally-endorsed targets requires that the relative benefits and effectiveness of potential interventions be explored rigorously within a quantitative framework.



A deterministic, compartmental transmission model (EPICYST) was developed to capture the dynamics of the taeniasis/cysticercosis disease system in the human and pig hosts. Cysticercosis prevalence in humans, an outcome of high epidemiological and clinical importance, was explicitly modelled. A next generation matrix approach was used to derive an expression for the basic reproduction number, R0. A full sensitivity analysis was performed using a methodology based on Latin-hypercube sampling partial rank correlation coefficient index.



EPICYST outputs indicate that chemotherapeutic intervention targeted at humans or pigs would be highly effective at reducing taeniasis and cysticercosis prevalence when applied singly, with annual chemotherapy of humans and pigs resulting, respectively, in 94 and 74% of human cysticercosis cases averted. Improved sanitation, meat inspection and animal husbandry are less effective but are still able to reduce prevalence singly or in combination. The value of R0for taeniasis was estimated at 1.4 (95% Credible Interval: 0.5-3.6).



Human- and pig-targeted drug-focussed interventions appear to be the most efficacious approach from the options currently available. The model presented is a forward step towards developing an informed control and elimination strategy for cysticercosis. Together with its validation against field data, EPICYST will be a valuable tool to help reach the WHO goals and to conduct economic evaluations of interventions in varying epidemiological settings.
Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London, W2 1PG, UK.|Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
Peter
P
Winskill
Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St. Mary's Campus, London, W2 1PG, UK.|Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
Wendy E
WE
Harrison
Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St. Mary's Campus, London, W2 1PG, UK.|Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London, W2 1PG, UK.|Current address: Research Triangle Institute, 701 13st Street NW, Washington D.C., 20005, USA.
Michael D
MD
French
Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
Matthew A
MA
Dixon
Neglected Zoonotic Diseases Team, Department of Neglected Tropical Diseases (NTD), World Health Organization (WHO), 20 Avenue Appia, 1211, Geneva 27, Switzerland.
Bernadette
B
Abela-Ridder
Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London, W2 1PG, UK. m.basanez@imperial.ac.uk.|London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London, W2 1PG, UK. m.basanez@imperial.ac.uk.
María-Gloria
0000-0001-5031-3361
MG
Basáñez
D000818:Animals; D003551:Cysticercosis / Q000469:parasitology / Q000517:prevention & control* / Q000635:transmission / Q000662:veterinary*; D006801:Humans; D008954:Models, Biological; D008962:Models, Theoretical; D000069466:Red Meat / Q000469:parasitology*; D013552:Swine; D013553:Swine Diseases / Q000469:parasitology / Q000517:prevention & control*; D041201:Taenia solium / Q000502:physiology*
Basic reproduction number; Cysticercosis; EPICYST; Intervention; Latin-hypercube sampling; Mathematical modelling; Neurocysticercosis; Partial rank correlation coefficient index; Taenia solium; Taeniasis; Tapeworm