Comparison between schistosomiasis transmission modelings considering acquired immunity and age-structured contact pattern with infested water

Yang, Hyun Mo

doi:10.1016/s0025-5564(03)00045-2

Cited by 15 publications

(4 citation statements)

References 38 publications

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“…Our estimates of the underlying ‘true’ age-prevalence for S. mansoni and for hookworm are in agreement with those obtained from transmission models [ 19 , 40 ] and from latent class statistical models [ 41 ]. For example, the S. mansoni age-prevalence is comparable to those obtained by the Yang et al [ 42 ] models, which differentiate between the influence of water contact patterns and the acquired immunity. However, due to large uncertainty in older age groups, our results do not allow choosing the transmission model, which resembles best.…”

Section: Discussionsupporting

confidence: 75%

Estimating sensitivity of the Kato-Katz technique for the diagnosis of Schistosoma mansoni and hookworm in relation to infection intensity

et al. 2017

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The Kato-Katz technique is the most widely used diagnostic method in epidemiologic surveys and drug efficacy trials pertaining to intestinal schistosomiasis and soil-transmitted helminthiasis. However, the sensitivity of the technique is low, particularly for the detection of light-intensity helminth infections. Examination of multiple stool samples reduces the diagnostic error; yet, most studies rely on a single Kato-Katz thick smear, thus underestimating infection prevalence. We present a model which estimates the sensitivity of the Kato-Katz technique in Schistosoma mansoni and hookworm, as a function of infection intensity for repeated stool sampling and provide estimates of the age-dependent ‘true’ prevalence. We find that the sensitivity for S. mansoni diagnosis is dominated by missed light infections, which have a low probability to be diagnosed correctly even through repeated sampling. The overall sensitivity strongly depends on the mean infection intensity. In particular at an intensity of 100 eggs per gram of stool (EPG), we estimate a sensitivity of 50% and 80% for one and two samples, respectively. At an infection intensity of 300 EPG, we estimate a sensitivity of 62% for one sample and 90% for two samples. The sensitivity for hookworm diagnosis is dominated by day-to-day variation with typical values for one, two, three, and four samples equal to 50%, 75%, 85%, and 95%, respectively, while it is only weakly dependent on the mean infection intensity in the population. We recommend taking at least two samples and estimate the ‘true’ prevalence of S. mansoni considering the dependence of the sensitivity on the mean infection intensity and the ‘true’ hookworm prevalence by taking into account the sensitivity given in the current study.

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Section: Discussionsupporting

confidence: 75%

Estimating sensitivity of the Kato-Katz technique for the diagnosis of Schistosoma mansoni and hookworm in relation to infection intensity

et al. 2017

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“…This is partially due to a slowly acquired level of immunity but is also due to the relationship between age and exposure; the very young and the very old are less prone to exposure to cercariae-infested water than those from school age and above. In studies in endemic areas it is repeatedly found that the peak of exposure and maximum worm burdens coincided in individuals with a mean age of between 10 and 20 years [36]. Since it does not kill the worms, the partial immunity can be seen as a parasite-driven mechanism to prevent super-infection that is potentially damaging to the host and therefore to the worms already present.…”

Section: Reasons For Hopementioning

confidence: 99%

Current status and future prospects for a vaccine against schistosomiasis

Lebens

Sun

Czerkinsky

et al. 2004

Expert Review of Vaccines

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Schistosomiasis remains an intractable problem in many parts of the world. Whereas the schistosome parasites cause little in the way of disease, their eggs become trapped in tissues of the host and elicit powerful and potentially damaging immune responses that are responsible for the pathology. Despite nearly four decades of effort there is still no effective vaccine against schistosomiasis, although a single vaccine candidate is undergoing clinical trials at present. Animal models have revealed much about disease progression and pathology. However, problems remain in identifying appropriate protective antigens to elicit immune responses that will attack the parasite but will not cross-react with egg antigens and thus increase the chance of developing severe chronic disease in individuals that have already been infected. This review summarizes the life-cycle of the parasite, current knowledge of pathogenesis and acquired immunity based on animal studies and observations in humans and the status of efforts in the vaccine development field.

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“…Humans are the principal definitive host for the five schistosome species. Adult worms live in the venous system of intestine (S. mansoni, S. japonicum, S. mekongi and S. intercalatum) or the urinary bladder (S. haematobium) [9,17,28]. Flooding can lead to severe schistosomiasis outbreaks [15,28,48].…”

Section: Kazeem Oare Okosun and Robert Smith?mentioning

confidence: 99%

Optimal control analysis of malaria–schistosomiasis co-infection dynamics

Okosun¹,

Smith²

2016

MBE

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This paper presents a mathematical model for malaria--schistosomiasis co-infection in order to investigate their synergistic relationship in the presence of treatment. We first analyse the single infection steady states, then investigate the existence and stability of equilibria and then calculate the basic reproduction numbers. Both the single-infection models and the co-infection model exhibit backward bifurcations. We carrying out a sensitivity analysis of the co-infection model and show that schistosomiasis infection may not be associated with an increased risk of malaria. Conversely, malaria infection may be associated with an increased risk of schistosomiasis. Furthermore, we found that effective treatment and prevention of schistosomiasis infection would also assist in the effective control and eradication of malaria. Finally, we apply Pontryagin's Maximum Principle to the model in order to determine optimal strategies for control of both diseases.

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Comparison between schistosomiasis transmission modelings considering acquired immunity and age-structured contact pattern with infested water

Cited by 15 publications

References 38 publications

Estimating sensitivity of the Kato-Katz technique for the diagnosis of Schistosoma mansoni and hookworm in relation to infection intensity

Estimating sensitivity of the Kato-Katz technique for the diagnosis of Schistosoma mansoni and hookworm in relation to infection intensity

Current status and future prospects for a vaccine against schistosomiasis

Optimal control analysis of malaria–schistosomiasis co-infection dynamics

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Comparison between schistosomiasis transmission modelings considering acquired immunity and age-structured contact pattern with infested water

Cited by 15 publications

References 38 publications

Estimating sensitivity of the Kato-Katz technique for the diagnosis of Schistosoma mansoni and hookworm in relation to infection intensity

Estimating sensitivity of the Kato-Katz technique for the diagnosis of Schistosoma mansoni and hookworm in relation to infection intensity

Current status and future prospects for a vaccine against schistosomiasis

Optimal control analysis of malaria&#8211;schistosomiasis co-infection dynamics

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Product

Resources

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Optimal control analysis of malaria–schistosomiasis co-infection dynamics