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  1. Article ; Online: Receptivity to malaria: meaning and measurement.

    Yukich, Joshua O / Lindblade, Kim / Kolaczinski, Jan

    Malaria journal

    2022  Volume 21, Issue 1, Page(s) 145

    Abstract: Receptivity" to malaria is a construct developed during the Global Malaria Eradication Programme (GMEP) era. It has been defined in varied ways and no consistent, quantitative definition has emerged over the intervening decades. Despite the lack of ... ...

    Abstract "Receptivity" to malaria is a construct developed during the Global Malaria Eradication Programme (GMEP) era. It has been defined in varied ways and no consistent, quantitative definition has emerged over the intervening decades. Despite the lack of consistency in defining this construct, the idea that some areas are more likely to sustain malaria transmission than others has remained important in decision-making in malaria control, planning for malaria elimination and guiding activities during the prevention of re-establishment (POR) period. This manuscript examines current advances in methods of measurement. In the context of a decades long decline in global malaria transmission and an increasing number of countries seeking to eliminate malaria, understanding and measuring malaria receptivity has acquired new relevance.
    MeSH term(s) Disease Eradication/methods ; Humans ; Malaria/prevention & control
    Language English
    Publishing date 2022-05-08
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 2091229-8
    ISSN 1475-2875 ; 1475-2875
    ISSN (online) 1475-2875
    ISSN 1475-2875
    DOI 10.1186/s12936-022-04155-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Modelling the impact of interventions on imported, introduced and indigenous malaria infections in Zanzibar, Tanzania.

    Das, Aatreyee M / Hetzel, Manuel W / Yukich, Joshua O / Stuck, Logan / Fakih, Bakar S / Al-Mafazy, Abdul-Wahid H / Ali, Abdullah / Chitnis, Nakul

    Nature communications

    2023  Volume 14, Issue 1, Page(s) 2750

    Abstract: Malaria cases can be classified as imported, introduced or indigenous cases. The World Health Organization's definition of malaria elimination requires an area to demonstrate that no new indigenous cases have occurred in the last three years. Here, we ... ...

    Abstract Malaria cases can be classified as imported, introduced or indigenous cases. The World Health Organization's definition of malaria elimination requires an area to demonstrate that no new indigenous cases have occurred in the last three years. Here, we present a stochastic metapopulation model of malaria transmission that distinguishes between imported, introduced and indigenous cases, and can be used to test the impact of new interventions in a setting with low transmission and ongoing case importation. We use human movement and malaria prevalence data from Zanzibar, Tanzania, to parameterise the model. We test increasing the coverage of interventions such as reactive case detection; implementing new interventions including reactive drug administration and treatment of infected travellers; and consider the potential impact of a reduction in transmission on Zanzibar and mainland Tanzania. We find that the majority of new cases on both major islands of Zanzibar are indigenous cases, despite high case importation rates. Combinations of interventions that increase the number of infections treated through reactive case detection or reactive drug administration can lead to substantial decreases in malaria incidence, but for elimination within the next 40 years, transmission reduction in both Zanzibar and mainland Tanzania is necessary.
    MeSH term(s) Humans ; Tanzania/epidemiology ; Malaria/epidemiology ; Malaria/prevention & control ; Incidence ; Prevalence ; Movement
    Language English
    Publishing date 2023-05-12
    Publishing country England
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, Non-U.S. Gov't
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-023-38379-8
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Effect of user preferences on ITN use: a review of literature and data.

    Koenker, Hannah / Yukich, Joshua O

    Malaria journal

    2017  Volume 16, Issue 1, Page(s) 233

    Abstract: Background: Insecticide-treated bed nets (ITNs) are the primary tool for vector control, and optimizing ITN use is a key concern of national programmes. Available evidence indicates that bed net users often have preferences for shape, colour, size, and ... ...

    Abstract Background: Insecticide-treated bed nets (ITNs) are the primary tool for vector control, and optimizing ITN use is a key concern of national programmes. Available evidence indicates that bed net users often have preferences for shape, colour, size, and other attributes, but it is unclear whether these preferences are strong enough to have any significant effect on bed net use, and whether countries and donors should invest in more expensive attributes in order to maximize ITN use. The link between bed net attributes, preferences, and use was investigated using a literature review and review of publicly available, nationally representative household surveys from sub-Saharan Africa.
    Methods: A literature search was conducted to identify publications with data on preferences for net attributes and on associations between net attributes and use. Publicly available DHS and MIS datasets were screened for variables on net preferences and net attributes. Wald tests were run to obtain odds ratios and confidence intervals for the use of nets of various attributes in univariate analysis. A multilevel logistic regression was constructed to assess the odds of a net's use, controlling for background variables and adding random effects variables at the household and cluster level.
    Results: Preferences for certain net attributes exist, but do not impede high rates of net use in countries where data were available. Stated preferences for shape and colour do not significantly influence net use to degrees that would require action by programme planners. By and large, people are using the nets they receive, and when they do not, it is for reasons unrelated to shape and size (primarily perceived mosquito density, heat or an excess of nets). Households in higher wealth quintiles tend to own greater numbers of conical nets, indicating that they have the ability to obtain or purchase these nets on their own, and individuals resident in higher wealth quintile households also use conical nets preferentially.
    Conclusions: The increased manufacturing costs for conical nets are not outweighed by the very small, often non-existent, increases in use rates in sub-Saharan Africa. Programmes that wish to explore the relationship between net attributes, preferences and use rates should include these questions in nationally representative household surveys to be able to capture trends across geographic and socio-economic groups.
    Language English
    Publishing date 2017-06-01
    Publishing country England
    Document type Journal Article
    ISSN 1475-2875
    ISSN (online) 1475-2875
    DOI 10.1186/s12936-017-1879-8
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Oviposition Activity and the Associated Socio-environmental Factors in the New Orleans Area.

    Thongsripong, Panpim / Carter, Brendan H / Ward, Matthew J / Jameson, Samuel B / Michaels, Sarah R / Yukich, Joshua O / Wesson, Dawn M

    Journal of medical entomology

    2023  Volume 60, Issue 2, Page(s) 392–400

    Abstract: The transmission of Aedes-borne viruses is on the rise globally. Their mosquito vectors, Aedes aegypti (Linnaeus, Diptera: Culicidae) and Ae. albopictus (Skuse, Diptera: Culicidae), are focally abundant in the Southern United States. Mosquito ... ...

    Abstract The transmission of Aedes-borne viruses is on the rise globally. Their mosquito vectors, Aedes aegypti (Linnaeus, Diptera: Culicidae) and Ae. albopictus (Skuse, Diptera: Culicidae), are focally abundant in the Southern United States. Mosquito surveillance is an important component of a mosquito control program. However, there is a lack of long-term surveillance data and an incomplete understanding of the factors influencing vector populations in the Southern United States. Our surveillance program monitored Ae. aegypti and Ae. albopictus oviposition intensity in the New Orleans area using ovicups in a total of 75 sites from 2009 to 2016. We found both Aedes spp. throughout the study period and sites. The average number of Ae. aegypti and Ae. albopictus hatched from collected eggs per site per week was 34.1 (SD = 57.7) and 29.0 (SD = 46.5), respectively. Based on current literature, we formed multiple hypotheses on how environmental variables influence Aedes oviposition intensity, and constructed Generalized Linear Mixed Effect models with a negative binomial distribution and an autocorrelation structure to test these hypotheses. We found significant associations between housing unit density and Ae. aegypti and Ae. albopictus oviposition intensity, and between median household income and Ae. albopictus oviposition intensity. Temperature, relative humidity, and accumulated rainfall had either a lagged or an immediate significant association with oviposition. This study provides the first long-term record of Aedes spp. distribution in the New Orleans area, and sheds light on factors associated with their oviposition activity. This information is vital for the control of potential Aedes-borne virus transmission in this area.
    MeSH term(s) Female ; Animals ; Aedes ; Oviposition ; New Orleans ; Mosquito Vectors ; Temperature
    Language English
    Publishing date 2023-01-23
    Publishing country England
    Document type Journal Article
    ZDB-ID 410635-0
    ISSN 1938-2928 ; 0022-2585
    ISSN (online) 1938-2928
    ISSN 0022-2585
    DOI 10.1093/jme/tjad007
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Modelling the implications of stopping vector control for malaria control and elimination.

    Yukich, Joshua O / Chitnis, Nakul

    Malaria journal

    2017  Volume 16, Issue 1, Page(s) 411

    Abstract: Background: Increasing coverage of malaria vector control interventions globally has led to significant reductions in disease burden. However due to its high recurrent cost, there is a need to determine if and when vector control can be safely scaled ... ...

    Abstract Background: Increasing coverage of malaria vector control interventions globally has led to significant reductions in disease burden. However due to its high recurrent cost, there is a need to determine if and when vector control can be safely scaled back after transmission has been reduced.
    Methods and findings: A mathematical model of Plasmodium falciparum malaria epidemiology was simulated to determine the impact of scaling back vector control on transmission and disease. A regression analysis of simulation results was conducted to derive predicted probabilities of resurgence, severity of resurgence and time to resurgence under various settings. Results indicate that, in the absence of secular changes in transmission, there are few scenarios where vector control can be removed without high expectation of resurgence. These, potentially safe, scenarios are characterized by low historic entomological inoculation rates, successful vector control programmes that achieve elimination or near elimination, and effective surveillance systems with high coverage and effective treatment of malaria cases.
    Conclusions: Programmes and funding agencies considering scaling back or withdrawing vector control from previously malaria endemic areas need to first carefully consider current receptivity and other available interventions in a risk assessment. Surveillance for resurgence needs to be continuously conducted over a long period of time in order to ensure a rapid response should vector control be withdrawn.
    MeSH term(s) Animals ; Anopheles/drug effects ; Humans ; Malaria, Falciparum/transmission ; Models, Theoretical ; Monte Carlo Method ; Mosquito Control/methods ; Mosquito Vectors/drug effects
    Language English
    Publishing date 2017-10-13
    Publishing country England
    Document type Journal Article
    ZDB-ID 2091229-8
    ISSN 1475-2875 ; 1475-2875
    ISSN (online) 1475-2875
    ISSN 1475-2875
    DOI 10.1186/s12936-017-2051-1
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Using a mobile nanopore sequencing lab for end-to-end genomic surveillance of Plasmodium falciparum: A feasibility study.

    Holzschuh, Aurel / Lerch, Anita / Fakih, Bakar S / Aliy, Safia Mohammed / Ali, Mohamed Haji / Ali, Mohamed Ali / Bruzzese, Daniel J / Yukich, Joshua / Hetzel, Manuel W / Koepfli, Cristian

    PLOS global public health

    2024  Volume 4, Issue 2, Page(s) e0002743

    Abstract: Genomic epidemiology holds promise for malaria control and elimination efforts, for example by informing on Plasmodium falciparum genetic diversity and prevalence of mutations conferring anti-malarial drug resistance. Limited sequencing infrastructure in ...

    Abstract Genomic epidemiology holds promise for malaria control and elimination efforts, for example by informing on Plasmodium falciparum genetic diversity and prevalence of mutations conferring anti-malarial drug resistance. Limited sequencing infrastructure in many malaria-endemic areas prevents the rapid generation of genomic data. To address these issues, we developed and validated assays for P. falciparum nanopore sequencing in endemic sites using a mobile laboratory, targeting key antimalarial drug resistance markers and microhaplotypes. Using two multiplexed PCR reactions, we amplified six highly polymorphic microhaplotypes and ten drug resistance markers. We developed a bioinformatics workflow that allows genotyping of polyclonal malaria infections, including minority clones. We validated the panels on mock dried blood spot (DBS) and rapid diagnostic test (RDT) samples and archived DBS, demonstrating even, high read coverage across amplicons (range: 580x to 3,212x median coverage), high haplotype calling accuracy, and the ability to explore within-sample diversity of polyclonal infections. We field-tested the feasibility of rapid genotyping in Zanzibar in close collaboration with the local malaria elimination program using DBS and routinely collected RDTs as sample inputs. Our assay identified haplotypes known to confer resistance to known antimalarials in the dhfr, dhps and mdr1 genes, but no evidence of artemisinin partial resistance. Most infections (60%) were polyclonal, with high microhaplotype diversity (median HE = 0.94). In conclusion, our assays generated actionable data within a few days, and we identified current challenges for implementing nanopore sequencing in endemic countries to accelerate malaria control and elimination.
    Language English
    Publishing date 2024-02-01
    Publishing country United States
    Document type Journal Article
    ISSN 2767-3375
    ISSN (online) 2767-3375
    DOI 10.1371/journal.pgph.0002743
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Outreach Training and Supportive Supervision for Quality Malaria Service Delivery: A Qualitative Evaluation in 11 Sub-Saharan African Countries.

    Altaras, Robin / Worges, Matt / La Torre, Sabrina / Audu, Bala M / Mwangi, Grace / Zeh-Meka, Albert / Yikpotey, Paul / Domkam Kammogne, Irenee / Chanda-Kapata, Pascalina / Vanderick, Caroline / Yukich, Joshua / Streat, Elizabeth

    The American journal of tropical medicine and hygiene

    2024  Volume 110, Issue 3_Suppl, Page(s) 20–34

    Abstract: Quality improvement of malaria services aims to ensure that more patients receive accurate diagnosis, appropriate treatment, and referral. The Outreach Training and Supportive Supervision Plus (OTSS+) approach seeks to improve health facility readiness ... ...

    Abstract Quality improvement of malaria services aims to ensure that more patients receive accurate diagnosis, appropriate treatment, and referral. The Outreach Training and Supportive Supervision Plus (OTSS+) approach seeks to improve health facility readiness and provider competency through onsite supportive supervision, troubleshooting, and on-the-job training. As part of a multicomponent evaluation, qualitative research was conducted to understand the value of the OTSS+ approach for malaria quality improvement. Semistructured key informant interviews, focus group discussions, and structured health facility-based interviews were used to gather stakeholder perspectives at subnational, national, and global levels. Data were collected globally and in 11 countries implementing OTSS+; in-depth data collection was done in four: Cameroon, Ghana, Niger, and Zambia. Study sites and participants were selected purposively. Verbatim transcripts were analyzed thematically, following the Framework approach. A total of 262 participants were included in the analysis; 98 (37.4%) were supervisees, 99 (37.8%) were supervisors, and 65 (24.8%) were other stakeholders. The OTSS+ approach was perceived to improve provider knowledge and skills in malaria service delivery and to improve data and supply management indirectly. Improvements were attributed to a combination of factors. Participants valued the relevance, adaptation, and digitization of supervision checklists; the quality and amount of contact with problem-solving supervisors; and the joint identification of problems and solutions, and development of action plans. Opportunities for improvement were digitized checklist refinement, assurance of a sufficient pool of supervisors, prioritization of health facilities, action plan dissemination and follow-up, and data review and use. The OTSS+ approach was perceived to be a useful quality improvement approach for malaria services.
    MeSH term(s) Humans ; Malaria/therapy ; Malaria/diagnosis ; Black People ; Surveys and Questionnaires ; Inservice Training ; Ghana
    Language English
    Publishing date 2024-02-06
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2942-7
    ISSN 1476-1645 ; 0002-9637
    ISSN (online) 1476-1645
    ISSN 0002-9637
    DOI 10.4269/ajtmh.23-0316
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: The association between household bed net ownership and all-cause child mortality in Madagascar.

    Meekers, Dominique / Yukich, Joshua O

    Malaria journal

    2016  Volume 15, Page(s) 475

    Abstract: Background: Malaria continues to be an important cause of morbidity and mortality in Madagascar. It has been estimated that the malaria burden costs Madagascar over $52 million annually in terms of treatment costs, lost productivity and prevention ... ...

    Abstract Background: Malaria continues to be an important cause of morbidity and mortality in Madagascar. It has been estimated that the malaria burden costs Madagascar over $52 million annually in terms of treatment costs, lost productivity and prevention expenses. One of the key malaria prevention strategies of the Government of Madagascar consists of large-scale mass distribution campaigns of long-lasting insecticide-treated bed nets (LLIN). Although there is ample evidence that child mortality has decreased in Madagascar, it is unclear whether increases in LLIN ownership have contributed to this decline. This study analyses multiple recent cross-sectional survey data sets to examine the association between household bed net ownership and all-cause child mortality.
    Results: Data on household-level bed net ownership confirm that the percentage of households that own one or more bed nets increased substantially following the 2009 and 2010 mass LLIN distribution campaigns. Additionally, all-cause child mortality in Madagascar has declined during the period 2008-2013. Bed net ownership was associated with a 22 % reduction in the all-cause child mortality hazard in Madagascar.
    Conclusions: Mass bed net distributions contributed strongly to the overall decline in child mortality in Madagascar during the period 2008-2013. However, the decline was not solely attributable to increases in bed net coverage, and nets alone were not able to eliminate most of the child mortality hazard across the island.
    MeSH term(s) Adolescent ; Adult ; Child Mortality ; Child, Preschool ; Cross-Sectional Studies ; Family Characteristics ; Female ; Humans ; Infant ; Infant, Newborn ; Insecticide-Treated Bednets/utilization ; Madagascar/epidemiology ; Male ; Middle Aged ; Ownership ; Young Adult
    Language English
    Publishing date 2016-09-17
    Publishing country England
    Document type Journal Article
    ISSN 1475-2875
    ISSN (online) 1475-2875
    DOI 10.1186/s12936-016-1520-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: The impact of reactive case detection on malaria transmission in Zanzibar in the presence of human mobility.

    Das, Aatreyee M / Hetzel, Manuel W / Yukich, Joshua O / Stuck, Logan / Fakih, Bakar S / Al-Mafazy, Abdul-Wahid H / Ali, Abdullah / Chitnis, Nakul

    Epidemics

    2022  Volume 41, Page(s) 100639

    Abstract: Malaria persists at low levels on Zanzibar despite the use of vector control and case management. We use a metapopulation model to investigate the role of human mobility in malaria persistence on Zanzibar, and the impact of reactive case detection. The ... ...

    Abstract Malaria persists at low levels on Zanzibar despite the use of vector control and case management. We use a metapopulation model to investigate the role of human mobility in malaria persistence on Zanzibar, and the impact of reactive case detection. The model was parameterized using survey data on malaria prevalence, reactive case detection, and travel history. We find that in the absence of imported cases from mainland Tanzania, malaria would likely cease to persist on Zanzibar. We also investigate potential intervention scenarios that may lead to elimination, especially through changes to reactive case detection. While we find that some additional cases are removed by reactive case detection, a large proportion of cases are missed due to many infections having a low parasite density that go undetected by rapid diagnostic tests, a low rate of those infected with malaria seeking treatment, and a low rate of follow up at the household level of malaria cases detected at health facilities. While improvements in reactive case detection would lead to a reduction in malaria prevalence, none of the intervention scenarios tested here were sufficient to reach elimination. Imported cases need to be treated to have a substantial impact on prevalence.
    MeSH term(s) Humans ; Malaria/diagnosis ; Malaria/epidemiology ; Malaria/prevention & control ; Prevalence ; Family Characteristics ; Surveys and Questionnaires ; Tanzania/epidemiology
    Language English
    Publishing date 2022-10-20
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S. ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2467993-8
    ISSN 1878-0067 ; 1755-4365
    ISSN (online) 1878-0067
    ISSN 1755-4365
    DOI 10.1016/j.epidem.2022.100639
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: An Investigation of Human–Mosquito Contact Using Surveys and Its Application in Assessing Dengue Viral Transmission Risk

    Thongsripong, Panpim / Qu, Zhuolin / Yukich, Joshua O / Hyman, James M / Wesson, Dawn M

    Journal of medical entomology. 2020 July 11, v. 57, no. 6

    2020  

    Abstract: Aedes-borne viral diseases such as dengue fever are surging in incidence in recent years. To investigate viral transmission risks, the availability of local transmission parameters is essential. One of the most important factors directly determining ... ...

    Abstract Aedes-borne viral diseases such as dengue fever are surging in incidence in recent years. To investigate viral transmission risks, the availability of local transmission parameters is essential. One of the most important factors directly determining infection risk is human–mosquito contact. Yet the contact rate is not often characterized, compared with other risk metrics such as vector density, because of the limited research tool options. In this study, human–mosquito contact was assessed in two study sites in the Southern United States using self-administered standardized survey instruments. The fraction of mosquito bites attributed to important vector species was estimated by human landing sampling. The survey participants reported a significantly higher outdoor mosquito bite exposure than indoor. The reported bite number was positively correlated with outdoor time during at-risk periods. There was also a significant effect of the study site on outdoor bite exposure, possibly due to the differing vector density. Thus, the levels of human–mosquito contact in this study were influenced both by the mosquito density and human behaviors. A dengue virus transmission model demonstrated that the observed difference in the contact rates results in differential virus transmission risks. Our findings highlight the practicality of using surveys to investigate human–mosquito contact in a setting where bite exposure levels differ substantially, and serve as a basis for further evaluations. This study underscores a new avenue that can be used in combination with other field methods to understand how changes in human behavior may influence mosquito bite exposure which drives mosquito-borne virus transmission.
    Keywords Culicidae ; Dengue virus ; arboviruses ; dengue ; human behavior ; humans ; medical entomology ; models ; risk ; surveys ; virus transmission
    Language English
    Dates of publication 2020-0711
    Size p. 1942-1954.
    Publishing place Entomological Society of America
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 410635-0
    ISSN 0022-2585
    ISSN 0022-2585
    DOI 10.1093/jme/tjaa134
    Database NAL-Catalogue (AGRICOLA)

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