A prospective sero-epidemiological study of visceral leishmaniasis in Baringo district, Rift Valley Province, Kenya

Schaefer, K. U.; Kurtzhals, Jørgen A. L.; Gachihi, G.; Muller, A.S.; Kager, Piet A.

doi:10.1016/0035-9203(95)90070-5

Cited by 58 publications

(46 citation statements)

References 12 publications

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“…5,11 Parasitologic confirmation might be the second-best standard for diagnosing VL, but not for diagnosing infection with L. donovani in a community at risk. Neither parasitology nor response to treatment are acceptable as a gold standard for L. donovani infection in humans, given the substantial proportion of asymptomatic infections in the community [26][27][28] and, to a lesser degree, the persistence of the serologic response in treated VL-patients. 29 In this study, we evaluated DAT validity for VL, and not for infection with the parasites that cause VL, in a series of VL patients and in persons without VL symptoms living in the same area at risk, i.e., the case-mix representative of an endemic area.…”

Section: Discussionmentioning

confidence: 99%

“…El Harith and others initially proposed a reciprocal titer of a 1: 3,200 serum dilution as the best trade-off between sensitivity and specificity. 5 This value was subsequently used in community surveys in Sudan, 15,27 Kenya, 26,30 and Bangladesh, 24 as well as in clinical work in Sudan, 14,25 Ethiopia, 29,31 and Bangladesh. 17 In Somalia, Shiddo and others used a cut-off titer of 1:800 for population screening because it optimized sensitivity and specificity.…”

Section: Discussionmentioning

confidence: 99%

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Operational validation of the direct agglutination test for diagnosis of visceral leishmaniasis.

Boelaert¹,

Safi²,

Jacquet

et al. 1999

The American Journal of Tropical Medicine and Hygiene

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Abstract. The validity of the direct agglutination test (DAT) for visceral leishmaniasis (VL) was studied with a standardized field kit on 148 clinically suspected persons and 176 healthy controls recruited between 1993 and 1994 from an endemic area in Gedaref State, Sudan. A sensitivity of 95.9% and a specificity of 99.4% were found at a 1: 8,000 cut-off titer when parasitologically confirmed cases were compared with healthy controls. While corroborating previously reported sensitivity and specificity estimates of this serodiagnostic test, this study examined the bias generated by commonly used test validation procedures. The fundamental methodologic problem in VL test validation is the absence of a reliable gold standard. Moreover, any operational guideline on DAT use has to consider the critical dependency of the predictive values of the test on VL prevalence rates. The DAT diagnostic cut-off titer depends upon many external factors, among which the prevalence of disease in the area and the case mix seem the most important.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Operational validation of the direct agglutination test for diagnosis of visceral leishmaniasis.

Boelaert¹,

Safi²,

Jacquet

et al. 1999

The American Journal of Tropical Medicine and Hygiene

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“…The global figure does not reflect the real importance of VL in affected communities, because VL has a focal distribution. Reported incidence rates of kala-azar in endemic areas vary between 2/1000 person-years in Kenya (Schaefer et al 1995), 14/1000 person-years in Ethiopia (Ali & Ashford 1994) and 40/1000 person-years in a community in eastern Sudan (Zijlstra et al 1994). Despite the considerable burden, there has been little attempt to quantify the economic consequences of the disease in these communities.…”

Section: Introductionmentioning

confidence: 99%

Drug policy for visceral leishmaniasis: a cost‐effectiveness analysis

Vanlerberghe

Diap

Guérin³

et al. 2007

Tropical Med Int Health

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Summaryobjective To facilitate the choice of the best visceral leishmaniasis (VL) treatment strategy for first-line health services in (VL)-endemic areas, we compared in a formal decision analysis the cost and the costeffectiveness of the different available options.methods We selected four drug regimens for VL on the basis of frequency of use, feasibility and reported efficacy studies. The point estimates and the range of plausible values of effectiveness and cost were retrieved from a literature review. A decision tree was constructed and the strategy minimizing the cost per death averted was selected.results Treatment with amphotericin B deoxycholate was the most effective approach in the baseline analysis and averted 87.2% of all deaths attributable to VL. The least expensive and the most costeffective treatment was the miltefosine regimen, and the most expensive and the least cost-effective was AmBisome Ò treatment. The cost of drug and medical care are the main determinants of the costeffectiveness ranking of the alternative schemes. Sensitivity analysis showed that antimonial was competitive with miltefosine in the low-resistance regions.conclusion In areas with >94% response rates to antimonials, generic sodium stibogluconate remains the most cost-effective option for VL treatment, mainly due to low drug cost. In other regions, miltefosine is the most cost-effective option of treatment, but its use as a first-line drug is limited by its teratogenicity and rapid resistance development. AmBisome in mono-or combination therapy is too expensive to compete in cost-effectiveness with the other regimens.keywords visceral leishmaniasis, drug policy, cost-effectiveness analysis

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“…The ratio of infection to disease varies for L. infantum in Brazil (6.5:1, 9:1, 18.5:1), Spain (50:1), Iran (13:1); L. donovani in Bangladesh (4:1), India and Nepal (8.9:1), and L. donovani in Sudan (7:1,1.5:1), Kenya (6:1, 4:1), and Ethiopia (5.6:1, 11:1) (Evans et al, 1992;Badaro et al, 1986b,a;Ali and Ashford, 1994;Schaefer et al, 1995;Zijlstra et al, 1994;Hailu et al, 2009;Davies and Mazloumi Gavgani, 1999). Chapman et al (2015) estimate that 20% of asymptomatic infections develop into KA in Bangladesh, which is higher than other estimates, but utilises individual, longitudinal data over 3 years.…”

Section: Natural History Of Vl Diseasementioning

confidence: 99%

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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A prospective sero-epidemiological study of visceral leishmaniasis in Baringo district, Rift Valley Province, Kenya

Cited by 58 publications

References 12 publications

Operational validation of the direct agglutination test for diagnosis of visceral leishmaniasis.

Operational validation of the direct agglutination test for diagnosis of visceral leishmaniasis.

Drug policy for visceral leishmaniasis: a cost‐effectiveness analysis

Progress in the Mathematical Modelling of Visceral Leishmaniasis

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