scholarly journals Modelling the impact of a Schistosoma mansoni vaccine and mass drug administration to achieve morbidity control and transmission elimination

2019 ◽  
Vol 13 (6) ◽  
pp. e0007349 ◽  
Author(s):  
Klodeta Kura ◽  
James E. Truscott ◽  
Jaspreet Toor ◽  
Roy M. Anderson
Keyword(s):  
Schistosoma Mansoni ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Morbidity Control ◽  
The Impact

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 Feasibility of onchocerciasis elimination using a “test-and-not-treat” strategy in Loa loa co-endemic areas

2020 ◽  
Author(s):  
David J Blok ◽  
Joseph Kamgno ◽  
Sebastien D Pion ◽  
Hugues C Nana-Djeunga ◽  
Yannick Niamsi-Emalio ◽  
...  
Keyword(s):  
Adverse Events ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Treatment Duration ◽  
Loa Loa ◽  
Serious Adverse Events ◽  
Endemic Areas ◽  
The Individual ◽  
The Impact ◽  
Main Strategy

Abstract Background Mass drug administration (MDA) with ivermectin is the main strategy for onchocerciasis elimination. Ivermectin is generally safe but associated with serious adverse events in individuals with high Loa loa microfilarial densities (MFD). Therefore, ivermectin MDA is not recommended in areas where onchocerciasis is hypo-endemic and L. loa is co-endemic. To eliminate onchocerciasis in those areas, a test-and-not-treat (TaNT) strategy has been proposed. We investigated whether onchocerciasis elimination can be achieved using TaNT and the required duration. Methods We used the individual-based model ONCHOSIM to predict the impact of TaNT on onchocerciasis microfilarial (mf) prevalence. We simulated pre-control mf prevalence levels from 2-40%. The impact of TaNT was simulated under varying levels of participation, systematic non-participation and exclusion from ivermectin due to high L. loa MFD. For each scenario, we assessed the time to elimination, defined as bringing onchocerciasis mf prevalence below 1.4%. Results In areas with 30-40% pre-control mf prevalence, the model predicted that it would take between 14 and 16 years to bring the mf prevalence below 1.4% using conventional MDA, assuming 65% participation. TaNT would increase the time to elimination by up to 1.5 years, depending on the level of systematic non-participation and the exclusion rate. At lower exclusion rates (≤2.5%), the delay would be less than six months. Conclusions Our model predicts that onchocerciasis can be eliminated using TaNT in L. loa co-endemic areas. The required treatment duration using TaNT would be only slightly longer than in areas with conventional MDA, provided that participation is good.

scholarly journals The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages

2021 ◽  
Vol 15 (5) ◽  
pp. e0009011
Author(s):  
Anneke S. de Vos ◽  
Wilma A. Stolk ◽  
Luc E. Coffeng ◽  
Sake J. de Vlas
Keyword(s):  
Intermediate Host ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Human Populations ◽  
Individual Based Model ◽  
Low Prevalence ◽  
The Impact ◽  
Local Transmission

Background The existence of locations with low but stable onchocerciasis prevalence is not well understood. An often suggested yet poorly investigated explanation is that the infection spills over from neighbouring locations with higher infection densities. Methodology We adapted the stochastic individual based model ONCHOSIM to enable the simulation of multiple villages, with separate blackfly (intermediate host) and human populations, which are connected through the regular movement of the villagers and/or the flies. With this model we explore the impact of the type, direction and degree of connectedness, and of the impact of localized or full-area mass drug administration (MDA) over a range of connected village settings. Principal findings In settings with annual fly biting rates (ABR) below the threshold needed for stable local transmission, persistence of onchocerciasis prevalence can well be explained by regular human traffic and/or fly movement from locations with higher ABR. Elimination of onchocerciasis will then theoretically be reached by only implementing MDA in the higher prevalence area, although lingering infection in the low prevalence location can trigger resurgence of transmission in the total region when MDA is stopped too soon. Expanding MDA implementation to the lower ABR location can therefore shorten the duration of MDA needed. For example, when prevalence spill-over is due to human traffic, and both locations have about equal populations, then the MDA duration can be shortened by up to three years. If the lower ABR location has twice as many inhabitants, the reduction can even be up to six years, but if spill-over is due to fly movement, the expected reduction is less than a year. Conclusions/Significance Although MDA implementation might not always be necessary in locations with stable low onchocerciasis prevalence, in many circumstances it is recommended to accelerate achieving elimination in the wider area.

scholarly journals Can direct smear results that are routinely collected at health centre level be used for monitoring the impact of mass drug administration with praziquantel on schistosomiasis in Burundi? A preliminary assessment.

2020 ◽  
Author(s):  
Paul BIZIMANA ◽  
Katja POLMAN ◽  
Giuseppina ORTU ◽  
Meryam KRIT ◽  
Frédéric NSABIYUMVA ◽  
...  
Keyword(s):  
Drug Administration ◽  
Mass Drug Administration ◽  
Health Centre ◽  
Health Information System ◽  
Routine Data ◽  
Direct Smear ◽  
Incidence Data ◽  
Intestinal Schistosomiasis ◽  
The Impact ◽  
Health Centre Level

Abstract Background : Intestinal schistosomiasis is still a public health problem in Burundi. Since 2008, annual mass drug administration with praziquantel have been rolled out in 11 endemic districts. The national programme relies on school-based surveys with Kato-Katz to monitor the impact of mass drug administration. We explored whether routine data on intestinal schistosomiasis as determined by direct fecal smears at health centre level could be used. Methods : From the Burundian National Health Information System, we collected routine incidence data on intestinal schistosomiasis as determined by direct smear examination in all 45 sanitary districts between 2011 and 2015. A temporal trends analysis was performed using a mixed negative binomial regression. Sanitary districts with mass drug administration campaigns with praziquantel (n=11) were compared with those without (n=34). In addition, prevalence data on intestinal schistosomiasis based on Kato-Katz results from a school-based national mapping in 2014 were compared with the incidence data in health centres based on direct smear results, in the same 45 sanitary districts. Findings : In the 11 sanitary districts applying mass drug administration with praziquantel, the incidence rate decreased significantly for the years 2014 (β 2014 =-0.826, p=0.010) and 2015 (β 2015 =-1.294, p<0.001) and for the five-year period (β=-0.286, p<0.001), whereas in the 34 districts where mass drug administration was not delivered, there was no significant decrease over time (β=-0.087, p=0.219). In most of the 45 sanitary districts, the low prevalences based on Kato-Katz in schoolchildren were confirmed by low incidence rates based on direct smear in the health centres. Conclusions : National Health Information System surveillance data, based on routinely collected direct smear results at health centre level, may be able to monitor the impact of mass drug administration with praziquantel on intestinal schistosomiasis in Burundi. Control and elimination of intestinal schistosomiasis call for integration of adequate diagnosis and treatment into routine activities of primary health care facilities, as recommended by the World Health Organization since more than 20 years. When moving towards elimination, more sensitive tests, such as the Point-of-care Circulating Cathodic Antigen assay are desirable. Keywords : Direct smear, Health centre, Mass drug administration, Monitoring, Praziquantel, Routine data, Schistosomiasis, Burundi

scholarly journals Schistosoma mansoni Mass Drug Administration Regimens and Their Effect on Morbidity among Schoolchildren over a 5-Year Period—Kenya, 2010–2015

2018 ◽  
Vol 99 (2) ◽  
pp. 362-369 ◽  
Author(s):  
Anita D. Sircar ◽  
Pauline N. M. Mwinzi ◽  
Isaac O. Onkanga ◽  
Ryan E. Wiegand ◽  
Susan P. Montgomery ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Drug Administration ◽  
Mass Drug Administration

EVALUATION OF LYMPHATIC FILARIASIS AFTER TWO ROUNDS OF MASS DRUG ADMINISTRATION IN LAU LOCAL GOVERNMENT AREA OF TARABA STATE NIGERIA

2021 ◽  
Vol 4 (4) ◽  
pp. 513-519
Author(s):  
D. E. Akafyi ◽  
I. S. Ndams ◽  
S. A. Luka ◽  
F. S. Ojeleye ◽  
S. O. Elkanah ◽  
...  
Keyword(s):  
Local Government ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Clinical Manifestations ◽  
Wuchereria Bancrofti ◽  
Local Government Area ◽  
Filarial Antigen ◽  
Physical Examinations ◽  
The Impact ◽  
Card Test

This study was undertaken to evaluate the effects of Mass Drug Administration (MDA) on Wuchereria bancrofti (microfilariae) after two rounds of combined Ivermectin and Albendazole distribution. A total of 221 participants were recruited in three communities in Lau Local Government Area of Taraba State by convenience sampling method. Questionnaires and physical examinations were used to assess clinical manifestations associated with the infection. Blood samples were collected by finger prick method and stained with Giemsa stain for examination to establish the presence of W. bancrofti while immunochromatographic card test was performed to determine the presence of filarial antigen in serum. Previous data were used to determine the pre-drug prevalence of the parasite. The results showed that the drug did not significantly reduce the clinical manifestations reported among the patients. The microfilariae prevalence and microfilaria mean density after two rounds of drug administration was 19.5% and 1.49%, while the pre- MDA prevalence and microfilaria mean density was 27.8% and 2.44% respectively. There was a statistically significant decrease of microfilaria prevalence (P<0.05) after two rounds of MDA. There was no significant effect of MDA by age, sex and occupation-related microfilariae prevalence in the study area.  In conclusion, the study reveals that microfilaria prevalence and load decreased after two rounds of MDA of combined Ivermectin and Albendazole distribution amongst the studied populations. Routine evaluation of the MDA is required to assess the impact of the drug for the eventual elimination of the infection.

scholarly journals Policy implications of the potential use of a novel vaccine to prevent infection with Schistosoma mansoni with or without mass drug administration

Vaccine ◽  
2020 ◽  
Vol 38 (28) ◽  
pp. 4379-4386 ◽  
Author(s):  
Klodeta Kura ◽  
Benjamin S. Collyer ◽  
Jaspreet Toor ◽  
James E. Truscott ◽  
T. Deirdre Hollingsworth ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Policy Implications ◽  
Potential Use

scholarly journals Optimising systemic insecticide use to improve malaria control

2019 ◽  
Vol 4 (6) ◽  
pp. e001776 ◽  
Author(s):  
Hannah R Meredith ◽  
Luis Furuya-Kanamori ◽  
Laith Yakob
Keyword(s):  
Vector Control ◽  
Malaria Transmission ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Companion Animals ◽  
Malaria Vectors ◽  
Systemic Insecticide ◽  
Blood Concentrations ◽  
Systemic Insecticides ◽  
The Impact

BackgroundLong-lasting insecticidal nets and indoor residual sprays have significantly reduced the burden of malaria. However, several hurdles remain before elimination can be achieved: mosquito vectors have developed resistance to public health insecticides, including pyrethroids, and have altered their biting behaviour to avoid these indoor control tools. Systemic insecticides, drugs applied directly to blood hosts to kill mosquitoes that take a blood meal, offer a promising vector control option. To date, most studies focus on repurposing ivermectin, a drug used extensively to treat river blindness. There is concern that overdependence on a single drug will inevitably repeat past experiences with the rapid spread of pyrethroid resistance in malaria vectors. Diversifying the arsenal of systemic insecticides used for mass drug administration would improve this strategy’s sustainability.MethodsHere, a review was conducted to identify systemic insecticide candidates and consolidate their pharmacokinetic/pharmacodynamic properties. The impact of alternative integrated vector control options and different dosing regimens on malaria transmission reduction are illustrated through mathematical model simulation.ResultsThe review identified drugs from four classes commonly used in livestock and companion animals: avermectins, milbemycins, isoxazolines and spinosyns. Simulations predicted that isoxazolines and spinosyns are promising candidates for mass drug administration, as they were predicted to need less frequent application than avermectins and milbemycins to maintain mosquitocidal blood concentrations.ConclusionsThese findings will provide a guide for investigating and applying different systemic insecticides to achieve more effective and sustainable control of malaria transmission.

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