scholarly journals The impact of mass drug administration on Schistosoma haematobium infection: what is required to achieve morbidity control and elimination?

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Klodeta Kura ◽  
Robert J. Hardwick ◽  
James E. Truscott ◽  
Jaspreet Toor ◽  
T. Deirdre Hollingsworth ◽  
...  
Keyword(s):  
Drug Administration ◽  
Mass Drug Administration ◽  
Schistosoma Haematobium ◽  
Treatment Guidelines ◽  
Public Health Problem ◽  
Data Availability ◽  
World Health ◽  
Morbidity Control ◽  
Health Organization ◽  
The Impact

Abstract Background Schistosomiasis remains an endemic parasitic disease causing much morbidity and, in some cases, mortality. The World Health Organization (WHO) has outlined strategies and goals to combat the burden of disease caused by schistosomiasis. The first goal is morbidity control, which is defined by achieving less than 5% prevalence of heavy intensity infection in school-aged children (SAC). The second goal is elimination as a public health problem (EPHP), achieved when the prevalence of heavy intensity infection in SAC is reduced to less than 1%. Mass drug administration (MDA) of praziquantel is the main strategy for control. However, there is limited availability of praziquantel, particularly in Africa where there is high prevalence of infection. It is therefore important to explore whether the WHO goals can be achieved using the current guidelines for treatment based on targeting SAC and, in some cases, adults. Previous modelling work has largely focused on Schistosoma mansoni, which in advance cases can cause liver and spleen enlargement. There has been much less modelling of the transmission of Schistosoma haematobium, which in severe cases can cause kidney damage and bladder cancer. This lack of modelling has largely been driven by limited data availability and challenges in interpreting these data. Results In this paper, using an individual-based stochastic model and age-intensity profiles of S. haematobium from two different communities, we calculate the probability of achieving the morbidity and EPHP goals within 15 years of treatment under the current WHO treatment guidelines. We find that targeting SAC only can achieve the morbidity goal for all transmission settings, regardless of the burden of infection in adults. The EPHP goal can be achieved in low transmission settings, but in some moderate to high settings community-wide treatment is needed. Conclusions We show that the key determinants of achieving the WHO goals are the precise form of the age-intensity of infection profile and the baseline SAC prevalence. Additionally, we find that the higher the burden of infection in adults, the higher the chances that adults need to be included in the treatment programme to achieve EPHP.

scholarly journals The Added Value of Water, Sanitation, and Hygiene Interventions to Mass Drug Administration for Reducing the Prevalence of Trachoma: A Systematic Review Examining

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Anyess Travers ◽  
Sheryl Strasser ◽  
Stephanie L. Palmer ◽  
Christine Stauber
Keyword(s):  
Systematic Review ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Added Value ◽  
World Health ◽  
Sanitation And Hygiene ◽  
Pubmed Database ◽  
Health Organization ◽  
Hygiene Education ◽  
The Impact

Trachoma is the leading cause of infectious blindness worldwide. The SAFE strategy, the World Health Organization-recommended method to eliminate blinding trachoma, combines developments in water, sanitation, surgery, and antibiotic treatment. Current literature does not focus on the comprehensive effect these components have on one another. The present systematic review analyzes the added benefit of water, sanitation, and hygiene education interventions to preventive mass drug administration of azithromycin for trachoma. Trials were identified from the PubMed database using a series of search terms. Three studies met the complete criteria for inclusion. Though all studies found a significant change in reduction of active trachoma prevalence, the research is still too limited to suggest the impact of the “F” and “E” components on trachoma prevalence and ultimately its effects on blindness.

scholarly journals Insights from quantitative and mathematical modelling on the proposed WHO 2030 goal for schistosomiasis

2019 ◽  
Vol 3 ◽  
pp. 1517 ◽  
Author(s):  
Keyword(s):  
Treatment Guidelines ◽  
Neglected Tropical Diseases ◽  
Public Health Problem ◽  
Control Measures ◽  
World Health ◽  
School Aged Children ◽  
The World ◽  
Health Organization ◽  
The Impact ◽  
Current Guidelines

Schistosomiasis remains one of the neglected tropical diseases (NTDs) impacting millions of people around the world. The World Health Organization (WHO) recently proposed a goal of elimination as a public health problem (EPHP) for schistosomiasis to be reached by 2030. Current WHO treatment guidelines for achieving EPHP focus on targeting school-aged children. The NTD Modelling Consortium has developed mathematical models to study schistosomiasis transmission dynamics and the impact of control measures. Our modelling insights on Schistosoma mansoni have shown that EPHP is likely to be attainable in low to moderate prevalence settings using the current guidelines. However, as prevalence rises within higher settings, EPHP is less likely to be achieved unless both school-aged children and adults are treated (with coverage levels increasing with the adult burden of infection). We highlight the challenges that are faced by treatment programmes, such as non-adherence to treatment and resurgence, which can hinder progress towards achieving and maintaining EPHP. Additionally, even though EPHP may be reached, prevalence can still be high due to persisting infections. Therefore, without elimination of transmission, treatment will likely have to continue to maintain EPHP. Further modelling work is being carried out, including extending our results to S. haematobium. By providing these modelling insights, we aim to inform discussions on the goals and treatment guidelines for schistosomiasis.

scholarly journals What is the impact of acquired immunity on the transmission of schistosomiasis and the efficacy of current and planned mass drug administration programmes?

2021 ◽  
Vol 15 (12) ◽  
pp. e0009946
Author(s):  
Klodeta Kura ◽  
Robert J. Hardwick ◽  
James E. Truscott ◽  
Roy M. Anderson
Keyword(s):  
Drug Administration ◽  
Mass Drug Administration ◽  
Public Health Problem ◽  
Basic Reproductive Number ◽  
World Health ◽  
Reproductive Number ◽  
Acquired Immunity ◽  
High Transmission ◽  
Age Related ◽  
The Impact

Schistosomiasis causes severe morbidity in many countries with endemic infection with the schistosome digenean parasites in Africa and Asia. To control and eliminate the disease resulting from infection, regular mass drug administration (MDA) is used, with a focus on school-aged children (SAC; 5–14 years of age). In some high transmission settings, the World Health Organization (WHO) also recommends the inclusion of at-risk adults in MDA treatment programmes. The question of whether ecology (age-dependant exposure) or immunity (resistance to reinfection), or some combination of both, determines the form of observed convex age-intensity profile is still unresolved, but there is a growing body of evidence that the human hosts acquire some partial level of immunity after a long period of repeated exposure to infection. In the majority of past research modelling schistosome transmission and the impact of MDA programmes, the effect of acquired immunity has not been taken into account. Past work has been based on the assumption that age-related contact rates generate convex horizontal age-intensity profiles. In this paper, we use an individual based stochastic model of transmission and MDA impact to explore the effect of acquired immunity in defined MDA programmes. Compared with scenarios with no immunity, we find that acquired immunity makes the MDA programme less effective with a slower decrease in the prevalence of infection. Therefore, the time to achieve morbidity control and elimination as a public health problem is longer than predicted by models with just age-related exposure and no build-up of immunity. The level of impact depends on the baseline prevalence prior to treatment (the magnitude of the basic reproductive number R0) and the treatment frequency, among other factors. We find that immunity has a larger impact within moderate to high transmission settings such that it is very unlikely to achieve morbidity and transmission control employing current MDA programmes.

scholarly journals Modelling the ability of mass drug administration to interrupt soil-transmitted helminth transmission: Community-based deworming in Kenya as a case study

2021 ◽  
Vol 15 (8) ◽  
pp. e0009625
Author(s):  
Nyuk Sian Chong ◽  
Stacey R. Smith? ◽  
Marleen Werkman ◽  
Roy M. Anderson
Keyword(s):  
Drug Administration ◽  
Mass Drug Administration ◽  
Neglected Tropical Diseases ◽  
Initial Conditions ◽  
Drug Efficacy ◽  
World Health ◽  
High Prevalence ◽  
Lower Drug ◽  
Health Organization ◽  
The Impact

The World Health Organization has recommended the application of mass drug administration (MDA) in treating high prevalence neglected tropical diseases such as soil-transmitted helminths (STHs), schistosomiasis, lymphatic filariasis, onchocerciasis and trachoma. MDA—which is safe, effective and inexpensive—has been widely applied to eliminate or interrupt the transmission of STHs in particular and has been offered to people in endemic regions without requiring individual diagnosis. We propose two mathematical models to investigate the impact of MDA on the mean number of worms in both treated and untreated human subpopulations. By varying the efficay of drugs, initial conditions of the models, coverage and frequency of MDA (both annual and biannual), we examine the dynamic behaviour of both models and the possibility of interruption of transmission. Both models predict that the interruption of transmission is possible if the drug efficacy is sufficiently high, but STH infection remains endemic if the drug efficacy is sufficiently low. In between these two critical values, the two models produce different predictions. By applying an additional round of biannual and annual MDA, we find that interruption of transmission is likely to happen in both cases with lower drug efficacy. In order to interrupt the transmission of STH or eliminate the infection efficiently and effectively, it is crucial to identify the appropriate efficacy of drug, coverage, frequency, timing and number of rounds of MDA.

scholarly journals Insights from quantitative and mathematical modelling on the proposed WHO 2030 goal for schistosomiasis

2019 ◽  
Vol 3 ◽  
pp. 1517
Author(s):  
Keyword(s):  
Treatment Guidelines ◽  
Neglected Tropical Diseases ◽  
Public Health Problem ◽  
Control Measures ◽  
World Health ◽  
School Aged Children ◽  
High Prevalence ◽  
The World ◽  
Health Organization ◽  
The Impact

Schistosomiasis remains one of the neglected tropical diseases (NTDs) impacting millions of people around the world. The World Health Organization (WHO) recently proposed a goal of elimination as a public health problem (EPHP) for schistosomiasis to be reached by 2030. Current WHO treatment guidelines for achieving EPHP focus on targeting school-aged children. The NTD Modelling Consortium has developed mathematical models to study schistosomiasis transmission dynamics and the impact of control measures. Our modelling insights on Schistosoma mansoni have shown that EPHP is likely to be attainable in low to moderate prevalence settings using the current guidelines. However, as prevalence rises within high prevalence settings, EPHP is less likely to be achieved unless both school-aged children and adults are treated (with coverage levels increasing with the adult burden of infection). We highlight the challenges that are faced by treatment programmes, such as non-adherence to treatment and resurgence, which can hinder progress towards achieving and maintaining EPHP. Additionally, even though EPHP may be reached, prevalence can still be high due to persisting infections. Therefore, without interruption of transmission, treatment will likely have to continue to maintain EPHP. Further modelling work is being carried out, including extending our results to S. haematobium. By providing these modelling insights, we aim to inform discussions on the goals and treatment guidelines for schistosomiasis.

Suicide in Developing Countries (1)

Crisis ◽  
2005 ◽  
Vol 26 (3) ◽  
pp. 104-111 ◽  
Author(s):  
Lakshmi Vijayakumar ◽  
K. Nagaraj ◽  
Jane Pirkis ◽  
Harvey Whiteford
Keyword(s):  
Developing Countries ◽  
Public Health Problem ◽  
Data Availability ◽  
World Health ◽  
Global Public Health ◽  
Socioeconomic Indicators ◽  
Suicide Rates ◽  
Country Level ◽  
Education Levels ◽  
Health Organization

Abstract. Objective. Suicide is a global public health problem, but relatively little epidemiological investigation of the phenomenon has occurred in developing countries. This paper aims to (1) examine the availability of rate data in developing countries, (2) provide a description of the frequency and distribution of suicide in those countries for which data are available, and (3) explore the relationship between country-level socioeconomic factors and suicide rates. It is accompanied by two companion papers that consider risk factors and preventive efforts associated with suicide in developing countries, respectively. Method. Using World Health Organization data, we calculated the average annual male, female, and total suicide rates during the 1990s for individual countries and regions (classified according to the Human Development Index [HDI]), and examined the association between a range of socioeconomic indicators and suicide rates. Results. For reasons of data availability, we concentrated on medium HDI countries. Suicide rates in these countries were variable. They were generally comparable with those in high HDI countries from the same region, with some exceptions. High education levels, high telephone density, and high per capita levels of cigarette consumption were associated with high suicide rates; high levels of inequality were associated with low suicide rates. Conclusion. Epidemiological investigations of this kind have the potential to inform suicide prevention efforts in developing countries, and should be encouraged.

scholarly journals Insights from mathematical modelling and quantitative analysis on the proposed WHO 2030 targets for visceral leishmaniasis on the Indian subcontinent

2019 ◽  
Vol 3 ◽  
pp. 1651
Author(s):  
Keyword(s):  
Public Health ◽  
Visceral Leishmaniasis ◽  
Health Problem ◽  
Indian Subcontinent ◽  
Public Health Problem ◽  
District Level ◽  
World Health ◽  
Kala Azar ◽  
Health Organization ◽  
The Impact

Visceral leishmaniasis (VL) is a neglected tropical disease (NTD) caused by Leishmania protozoa that are transmitted by female sand flies. On the Indian subcontinent (ISC), VL is targeted by the World Health Organization (WHO) for elimination as a public health problem by 2020, which is defined as <1 VL case (new and relapse) per 10,000 population at district level in Nepal and sub-district level in Bangladesh and India. WHO is currently in the process of formulating 2030 targets, asking whether to maintain the 2020 target or to modify it, while adding a target of zero mortality among detected cases. The NTD Modelling Consortium has developed various mathematical VL transmission models to gain insight into the transmission dynamics of VL, identify the main knowledge gaps, and predict the feasibility of achieving and sustaining the targets by simulating the impact of varying intervention strategies. According to the models, the current target is feasible at the appropriate district/sub-district level in settings with medium VL endemicities (up to 5 reported VL cases per 10,000 population per year) prior to the start of the interventions. However, in settings with higher pre-control endemicities, additional efforts may be required. We also highlight the risk that those with post-kala-azar dermal leishmaniasis (PKDL) may pose to reaching and sustaining the VL targets, and therefore advocate adding control of PKDL cases to the new 2030 targets. Spatial analyses revealed that local hotspots with high VL incidence remain. We warn that the current target provides a perverse incentive to not detect/report cases as the target is approached, posing a risk for truly achieving elimination as a public health problem although this is taken into consideration by the WHO procedures for validation. Ongoing modelling work focuses on the risk of recrudescence when interventions are relaxed after the elimination target has been achieved.

scholarly journals A community survey of coverage and adverse events following country-wide triple-drug mass drug administration for lymphatic filariasis elimination, Samoa 2018

2020 ◽  
Vol 14 (11) ◽  
pp. e0008854
Author(s):  
Gabriela A. Willis ◽  
Helen J. Mayfield ◽  
Therese Kearns ◽  
Take Naseri ◽  
Robert Thomsen ◽  
...  
Keyword(s):  
Adverse Events ◽  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Total Population ◽  
Community Survey ◽  
World Health ◽  
Cross Sectional ◽  
Eligible Population ◽  
Health Organization

The Global Programme to Eliminate Lymphatic Filariasis has made considerable progress but is experiencing challenges in meeting targets in some countries. Recent World Health Organization guidelines have recommended two rounds of triple-drug therapy with ivermectin, diethylcarbamazine (DEC), and albendazole (IDA), in areas where mass drug administration (MDA) results with two drugs (DEC and albendazole) have been suboptimal, as is the case in Samoa. In August 2018, Samoa was the first country in the world to implement countrywide triple-drug MDA. This paper aims to describe Samoa’s experience with program coverage and adverse events (AEs) in the first round of triple-drug MDA. We conducted a large cross-sectional community survey to assess MDA awareness, reach, compliance, coverage and AEs in September/October 2018, 7–11 weeks after the first round of triple-drug MDA. In our sample of 4420 people aged ≥2 years (2.2% of the population), age-adjusted estimates indicated that 89.0% of the eligible population were offered MDA, 83.9% of the eligible population took MDA (program coverage), and 80.2% of the total population took MDA (epidemiological coverage). Overall, 83.8% (2986/3563) reported that they did not feel unwell at all after taking MDA. Mild AEs (feeling unwell but able to do normal everyday things) were reported by 13.3% (476/3563) and moderate or severe AEs (feeling unwell and being unable to do normal everyday activities such as going to work or school) by 2.9% (103/3563) of participants. This study following the 2018 triple-drug MDA in Samoa demonstrated a high reported program awareness and reach of 90.8% and 89.0%, respectively. Age-adjusted program coverage of 83.9% of the total population showed that MDA was well accepted and well tolerated by the community.

scholarly journals Trachoma Prevalence After Discontinuation of Mass Azithromycin Distribution

2020 ◽  
Vol 221 (Supplement_5) ◽  
pp. S519-S524
Author(s):  
William Godwin ◽  
Joaquin M Prada ◽  
Paul Emerson ◽  
P J Hooper ◽  
Ana Bakhtiari ◽  
...  
Keyword(s):  
Public Health ◽  
Diagnostic Tests ◽  
Public Health Problem ◽  
World Health ◽  
Simulation Based ◽  
The World ◽  
Health Organization ◽  
Program Cycle ◽  
The Impact ◽  
Oral Azithromycin

Abstract Background As the World Health Organization seeks to eliminate trachoma by 2020, countries are beginning to control the transmission of trachomatous inflammation–follicular (TF) and discontinue mass drug administration (MDA) with oral azithromycin. We evaluated the effect of MDA discontinuation on TF1–9 prevalence at the district level. Methods We extracted from the available data districts with an impact survey at the end of their program cycle that initiated discontinuation of MDA (TF1–9 prevalence &lt;5%), followed by a surveillance survey conducted to determine whether TF1–9 prevalence remained below the 5% threshold, warranting discontinuation of MDA. Two independent analyses were performed, 1 regression based and 1 simulation based, that assessed the change in TF1–9 from the impact survey to the surveillance survey. Results Of the 220 districts included, TF1–9 prevalence increased to &gt;5% from impact to surveillance survey in 9% of districts. Regression analysis indicated that impact survey TF1–9 prevalence was a significant predictor of surveillance survey TF1–9 prevalence. The proportion of simulations with &gt;5% TF1–9 prevalence in the surveillance survey was 2%, assuming the survey was conducted 4 years after MDA. Conclusion An increase in TF1–9 prevalence may represent disease resurgence but could also be due to measurement error. Improved diagnostic tests are crucial to elimination of TF1–9 as a public health problem.

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