Mathematical analysis of the dynamics of visceral leishmaniasis in the Sudan

ELmojtaba, Ibrahim M.; Mugisha, Johnny; Hashim, Mohsin

doi:10.1016/j.amc.2010.07.069

Cited by 43 publications

(64 citation statements)

References 34 publications

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“…Conversely the additional population(s) may drive infection in the primary hosts, or, in this case, stifle the effects of control upon just the primary population through treatment of infective VL humans. Under the parameterisation of ELmojtaba et al (2010a) the removal of this secondary population was beneficial to humans although the reduction in R N GM 0 was relatively paltry (3.4 down to 2.3) and indicates that whilst infection is boosted by the animal reservoir, it is not sustained by it.…”

Section: Other Animal Hostsmentioning

confidence: 99%

“…PKDL patients are assumed to be treated or to spontaneously recover (with rate η H ) and once again become non-infectious. ELmojtaba et al (2010aELmojtaba et al ( ,b, 2012) with both KA (I H ) and PKDL (P H ) classes and red denoting the infective classes. Following KA, patients either develop PKDL with probability f or recover immediately.…”

Section: Infection In Humansmentioning

confidence: 99%

“…Stauch et al (2011Stauch et al ( , 2012Stauch et al ( , 2014 later on discount animal reservoirs by setting a = 1, but ELmojtaba et al (2010a) use this type of ROI in their model analysis to examine control via this reservoir (see Section 4.4). Even if animals play no role, the same formulation can be used with a < 1 but I A = 0 in order to model the reduction in biting due to presence of animals (i.e.…”

Section: Sandfly Host Choicementioning

confidence: 99%

“…The first transmission model to include this disease state was by ELmojtaba et al (2010a) who modelled infection in Sudan; this model was later extended (ELmojtaba et al, 2010b(ELmojtaba et al, , 2012). The compartmental model was a typical SIR-type model with an extra infected (and infectious) compartment for PKDL patients (see Figure 3).…”

Section: Infection In Humansmentioning

confidence: 99%

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Progress in the Mathematical Modelling of Visceral Leishmaniasis

Rock¹,

Quinnell²,

Medley³

et al. 2016

Advances in Parasitology

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The leishmaniases comprise a complex of diseases characterised by clinical outcomes that range from self-limiting to chronic, disfiguring and stigmatising, to life-threatening. Diagnostic methods, treatments, and vector and reservoir control options exist, but deciding the most effective interventions requires a quantitative understanding of the population level infection and disease dynamics. The effectiveness of any set of interventions has to be determined within the context of operational conditions, including economic and political commitment. Mathematical models are the best available tools for studying quantitative systems crossing disciplinary spheres (biology, medicine, economics) within environmental and societal constraints.In 2005, the World Health Assembly and government health ministers of India, Nepal, and Bangladesh signed a Memorandum of Understanding to eliminate the life threatening form of leishmaniasis, visceral leishmaniasis (VL), on the Indian subcontinent by 2015 through a combination of early case detection, improved treatments, and vector control. The elimination target is <1/10,000 population at the district or subdistrict level compared to the current 20/10,000 in the regions of highest transmission.Towards this goal, this chapter focuses on mathematical models of VL, and the biology driving those models, to enable realistic predictions of the * Corresponding author Email address: orin.courtenay@warwick.ac.uk (Orin Courtenay)Preprint submitted to Advances in Parasitology July 18, 2016 best combination of interventions. Several key issues will be discussed which have affected previous modelling of VL and the direction future modelling may take. Current understanding of the natural history of disease, immunity (and loss of immunity), as well as stages of infection and their durations are considered particularly for humans, but also for dogs. Asymptomatic and clinical infection are discussed in the context of their relative roles in Leishmania transmission, as well as key components of the parasite-sandfly-vector interaction and intervention strategies including diagnosis, treatment and vector control. Gaps in current biological knowledge and potential avenues to improve model structures and mathematical predictions are identified. Underpinning the marriage between biology and mathematical modelling, the content of this chapter represents the first step towards developing the next generation of models for VL.

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Section: Other Animal Hostsmentioning

confidence: 99%

Section: Infection In Humansmentioning

confidence: 99%

Section: Sandfly Host Choicementioning

confidence: 99%

Section: Infection In Humansmentioning

confidence: 99%

See 2 more Smart Citations

Progress in the Mathematical Modelling of Visceral Leishmaniasis

Rock¹,

Quinnell²,

Medley³

et al. 2016

Advances in Parasitology

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show abstract

“…Article ID 9 (Elmojtaba et al, 2010) i. Description: The authors presented a SIR model for the transmission of visceral leishmaniosis between humans, reservoir animals and the vector in Sudan ( Figure 69); unlike other models, this model assumes that humans can become either immune or a reservoir.…”

Section: Supporting Publications 2013:en-466 196mentioning

confidence: 99%

Data collection to characterise the impact of canine leishmaniosis and modelling of the role of animals in spreading Leishmania infantum within the European Union

Mattin

Brodbelt

Wylie

et al. 2014

EFSA Supporting Publications

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Canine leishmaniosis (CanL) is a major zoonosis transmitted by sand flies which can potentially cause severe fatal disease in humans and dogs. The disease is endemic in southern Europe and there are concerns about its introduction into the non-endemic areas of the European Union (EU). The objectives of this work were to investigate the efficacy of different control measures using a systematic review (SR), assess the role of dogs in the spread of Leishmania Infantum (L. infantum) in the EU and evaluate potential mitigation measures using simulation modelling, and evaluate the impact of the disease in endemic areas. The SR evaluated the effectiveness and safety of control measures for CanL using 23 clinical trials conducted on a total of 5861 dogs. Significant benefits were observed in the intervention groups for a number of vaccine types, deltamethrin collars, spot-ons, and prophylactic medication with domperidone. However, these results require confirmation in adequately powered well designed randomised controlled trials. The results of the stochastic simulation modelling suggest that there is a high risk of endemicity for disease-free EU regions with presence of a competent vector and where infected dogs are introduced. When evaluated individually and at a high level of implementation, the best mitigation measures in decreasing order of effectiveness were: repellent, vaccine, prophylactic medication and insecticide. Some combinations of mitigation measures showed a joint effect higher than the effect of individual measures. Test and exclusion of positive dogs moving into non-endemic areas was effective for low numbers of imports, but its benefits diminished as the number of imported dogs increased, given the low sensitivity of the diagnostic test used. The results of the impact assessment suggest clinical CanL is a common diagnosis in endemic parts of the EU. The estimated percentage of practice-attending dogs with a veterinary diagnosis of CanL by country was as follows: France 0.71%, Spain 3.71%, Portugal 2.92%, Italy 4.25% and Greece 7.80%. CanL can have a significant impact on the welfare of affected dogs and economic implications for owners, both for prevention and treatment. It is estimated that the use of preventative collars in these five countries cost dog owners €54 million in 2012 alone. The incidence of clinical human leishmaniosis is much lower than CanL, with reported data suggesting between 20 and 380 hospital admissions per country per year. Costs relating to hospital fees and time off work may amount to approximately €4.5million/year in Spain, Portugal, Italy and Greece. The current economic crisis is likely to have an adverse impact on the prevention and control of CanL.

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Vaccination model for visceral leishmaniasis with infective immigrants

ELmojtaba

Mugisha

Hashim

2012

Math Methods in App Sciences

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In this paper, we present and analyzed a mathematical model that describes the dynamics of visceral leishmaniasis in a population with immigration of infective humans under mass vaccination strategy. Our result shows that in order for the vaccine to play a role on disease control, it must be very effective. Results also show that vaccination coverage does not have any impact on disease control when the immigration rate is small, and it does not affect the long‐term behavior when the immigration rate is high. In the case of no immigration of infective, our system has disease‐free equilibrium, and it is globally asymptotically stable when scriptR0, the basic reproduction number, is less than unity. Numerical simulation shows that in the case of no immigration of infective, our system undergoes forward bifurcation when scriptR0 passes throw unity. Copyright © 2012 John Wiley & Sons, Ltd.

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Mathematical analysis of the dynamics of visceral leishmaniasis in the Sudan

Cited by 43 publications

References 34 publications

Progress in the Mathematical Modelling of Visceral Leishmaniasis

Progress in the Mathematical Modelling of Visceral Leishmaniasis

Data collection to characterise the impact of canine leishmaniosis and modelling of the role of animals in spreading Leishmania infantum within the European Union

Vaccination model for visceral leishmaniasis with infective immigrants

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