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result(s) for
"transmission season"
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Dry-season transmission and determinants of Plasmodium infections in Jawi district, northwest Ethiopia
by
Lemma, Wossenseged
,
Amare, Andualem
,
Eshetu, Tegegne
in
Analysis
,
Biomedical and Life Sciences
,
Biomedicine
2022
Background
Malaria remains a serious global public health problem, and continues to have a devastating impact on people’s health worldwide. Continuous monitoring and evaluation of current malaria transmission status in different seasons is a mainstay for the success of ongoing intervention strategies for malaria. The purpose of this study was to assess the dry-season transmission and determinants of malaria in Jawi district, northwest Ethiopia.
Methods
A community-based cross-sectional study was conducted from January 13 to February 11, 2020; among selected Kebeles in the Jawi district. A multistage sampling technique was used in this study. Random and systematic sampling techniques were carried out to select
Kebeles
and each household, respectively. Light microscopy and CareStart™ Malaria HRP2/pLDH (Pf/Pv) Combo RDT were implemented to determine the prevalence of malaria. Moreover, associated risk factors in the prevalence of malaria were assessed by using a bivariate and multivariate logistic regression model.
Results
A total of 219 study participants were enrolled in this study. Of the total enrolled individuals, malaria cases were found among 36 individuals with a positivity rate of 16.4% (95% CI 11.4–21.5).
Plasmodium falciparum
was the predominant species with an estimated prevalence of 87.0% in the study areas. Interrupted utilization of ITN (AOR = 4.411, 95% CI 1.401–13.880), using over 3 years older ITNs (AOR = 9.622, 95% CI 1.881–49.214), travel history (AOR = 12.703, 95% CI 2.441–66.114), living in a house with holes on the wall (AOR = 3.811, 95% CI 1.010–14.384), and living in a house with an eave (AOR = 4.23, 95% CI 1.065–16.801) significantly increased the probability of malaria positivity rate.
Conclusion
Malaria is still an important public health burden among individuals in the Jawi district. Interrupted utilization of ITNs, using over 3 years older ITNs, living in a house with holes on the wall, living in a house with an eave, and travel history were identified as the risk factors of malaria. Therefore, the District health office and Health extension workers should promote daily utilization of good ITNs and improve housing conditions to reduce malaria prevalence.
Journal Article
Sub-national tailoring of seasonal malaria chemoprevention in Mali based on malaria surveillance and rainfall data
by
Berthé, Ibrahima
,
Katilé, Abdoulaye
,
Gaudart, Jean
in
Antimalarials
,
Asymptomatic
,
Biomedical and Life Sciences
2022
Background
In malaria endemic countries, seasonal malaria chemoprevention (SMC) interventions are performed during the high malaria transmission in accordance with epidemiological surveillance data. In this study we propose a predictive approach for tailoring the timing and number of cycles of SMC in all health districts of Mali based on sub-national epidemiological surveillance and rainfall data. Our primary objective was to select the best of two approaches for predicting the onset of the high transmission season at the operational scale. Our secondary objective was to evaluate the number of malaria cases, hospitalisations and deaths in children under 5 years of age that would be prevented annually and the additional cost that would be incurred using the best approach.
Methods
For each of the 75 health districts of Mali over the study period (2014–2019), we determined (1) the onset of the rainy season period based on weekly rainfall data; (ii) the onset and duration of the high transmission season using change point analysis of weekly incidence data; and (iii) the lag between the onset of the rainy season and the onset of the high transmission. Two approaches for predicting the onset of the high transmission season in 2019 were evaluated.
Results
In the study period (2014–2019), the onset of the rainy season ranged from week (W) 17 (W17; April) to W34 (August). The onset of the high transmission season ranged from W25 (June) to W40 (September). The lag between these two events ranged from 5 to 12 weeks. The duration of the high transmission season ranged from 3 to 6 months. The best of the two approaches predicted the onset of the high transmission season in 2019 to be in June in two districts, in July in 46 districts, in August in 21 districts and in September in six districts. Using our proposed approach would prevent 43,819 cases, 1943 hospitalisations and 70 deaths in children under 5 years of age annually for a minimal additional cost. Our analysis shows that the number of cycles of SMC should be changed in 36 health districts.
Conclusion
Adapting the timing of SMC interventions using our proposed approach could improve the prevention of malaria cases and decrease hospitalisations and deaths. Future studies should be conducted to validate this approach.
Graphical Abstract
Journal Article
Long-term shifts in the seasonal abundance of adult Culicoides biting midges and their impact on potential arbovirus outbreaks
2019
Surveillance of adult Culicoides biting midge flight activity is used as an applied ecological method to guide the management of arbovirus incursions on livestock production in Europe and Australia. To date the impact of changes in the phenology of adult vector activity on arbovirus transmission has not been defined. We investigated this at two sites in the UK, identifying 150,000 Culicoides biting midges taken from 2867 collections over a nearly 40 year timescale. Whilst we recorded no change in seasonal activity at one site, shifts in first adult appearance and last adult appearance increased the seasonal activity period of Culicoides species at the other site by 40 days over the time period. Lengthening of the adult activity season was driven by an increase in abundance of Culicoides and correlated with local increases in temperature and precipitation. This diversity in responses poses significant challenges for predicting future transmission and overwintering risk. Policy implications. Our analysis not only shows a dramatic and consistent increase in the adult active period of Culicoides biting midges, but also that this varies significantly between sites. This suggests broad‐scale analyses alone are insufficient to understand the potential impacts of changes in climate on arbovirus vector populations. Understanding the impact of climate change on adult Culicoides seasonality and transmission of arboviruses requires the context of changes in a range of other local ecological drivers.
Journal Article
Seasonal changes of infectivity rates of Bancroftian filariasis vectors in coast province, Kenya
2009
Bancroftian filariasis in Kenya is endemic in coastal districts with an estimated number of 2.5 million people at risk of infection. The main mosquito genera involved in transmission of Wuchereria bancrofti in these areas are Anopheles, Culex and Mansonia. The study was envisaged to compare the infectivity rates of Bancroftian filariasis vectors between the high transmission (wet) and the low transmission (dry) seasons.
Mosquitoes were sampled from houses and compounds from two study sites, Gazi and Madunguni, on the Kenyan coast. Day resting indoor collection (DRI), pyrethrum spray catch (PSC) and CDC light traps were used to collect mosquitoes. After identification, female mosquitoes were dissected to search for W. bancrofti III stage larvae.
A total of 1832 female mosquitoes were dissected. Infectivity rates of vectors in Madunguni were 1.49 and 0.21% in wet and dry seasons respectively, whereas in Gazi, these were 1.69 and 0%, respectively. There was a significant difference in the infectivity rates between the two seasons in both Madunguni and Gazi villages (p <0.05). Anopheles gambiae s.l. was the main vector in both study sites followed by Culex quinquefasciatus and An. funestus.
There was a difference in infectivity rates of Bancroftian filariasis vectors between the wet and dry seasons. The abundance of An. gambiae s.s. during the transmission season could be responsible for the increased infectivity rates of vectors in this season.
Journal Article
Association between Transmission Season and Degree of Severity in Guillain-Barre Syndrome
by
Marjianto, Irma Rizkika
,
Hamdan, Muhammad
,
Fadil
in
Diarrhea
,
Guillain-Barre syndrome
,
Infectious diseases
2020
Guillain-barre syndrome (GBS) is a common cause of acute severe paralysis. This weakness makes people with GBS could not move for a long time, thus disrupting the productivity of the patient. GBS usually occurs after an infectious disease in which the immune response produces cross-reacting antibodies with gangliosides in the neural membrane. Seasonal variations in GBS could be caused by the season of infectious disease that proceeds and it affects the weight of GBS. The study was conducted retrospectively, case-control study, using the hospitalized patient records of GBS patients in Dr. Soetomo Teaching Hospital, Surabaya, which meets the inclusion and exclusion criteria, from January 2013 to October 2016. GBS severity is assessed using the Medical research council (MRC) sum score. The case group was GBS with a severe severity which has a value <36. There were 82 subjects that consist of 41 case groups and 41 control groups. In the case group with the onset of transition symptoms during the transition season, there were 21 people 51.2% more than 15 the control group 36.6%. In contrast, in the control group, the onset symptom was not the transition season, 26 people 63.4% than the case group of 20 people 48.8%. However, this difference was not statistically significant with p = 0.182 and research objectives (RO) 1.82 (CI 95% 0.753-4.399). There was no correlation between the transmission season and the severity of GBS.
Journal Article
The influence of transmission season on parasitological cure rates and intensity of infection after praziquantel treatment of Schistosoma haematobium-infected schoolchildren in Mozambique
2009
Schistosoma haematobium is refractory to praziquantel (PZQ) during the prepatent period of infection. A hypothesis based on this observation is that in areas where S. haematobium transmission is seasonal, the outcome of chemotherapy depends on the timing of the treatment relative to the annual transmission pattern. To examine this hypothesis, a study was carried out in southern Mozambique. Following demonstration of seasonal transmission, PZQ was administered separately to two cohorts of S. haematobium-infected schoolchildren in (1) the high and (2) the low transmission seasons and followed up after two months when levels of infection and intensities were measured. The prevalence of infection decreased from 54·2% and 51·7% in cohorts 1 and 2 to 30·3% and 1·8%, respectively. The geometric mean intensity of infection decreased from 23·3 eggs/10 ml of urine at baseline to 15·6 eggs/10 ml of urine in cohort 1 (treated during high transmission season), and from 23·5 eggs/10 ml urine to 7·3 eggs/10 ml of urine in cohort 2 (treated during low transmission season). The observed cure rates in cohorts 1 and 2 were 69·7% and 98·2%, respectively. Differences in infection between the cohorts in terms of cure rate and level of infection two months post-treatment were statistically significant and indicate that in areas with a seasonal transmission pattern, the effect of PZQ can be enhanced if treatment takes place during the low transmission season. We conclude that appropriately timed PZQ administration will increase the impact of schistosomiasis control programmes.
Journal Article
Seasonal performance of a malaria rapid diagnosis test at community health clinics in a malaria-hyperendemic region of Burkina Faso
by
Ouédraogo, Espérance
,
Ouédraogo, Alphonse
,
Tiono, Alfred
in
Biomedical and Life Sciences
,
Biomedical research
,
Biomedicine
2012
BACKGOUND: Treatment of confirmed malaria patients with Artemisinin-based Combination Therapy (ACT) at remote areas is the goal of many anti-malaria programs. Introduction of effective and affordable malaria Rapid Diagnosis Test (RDT) in remote areas could be an alternative tool for malaria case management. This study aimed to assess performance of the OptiMAL dipstick for rapid malaria diagnosis in children under five. METHODS: Malaria symptomatic and asymptomatic children were recruited in a passive manner in two community clinics (CCs). Malaria diagnosis by microscopy and RDT were performed. Performance of the tests was determined. RESULTS: RDT showed similar ability (61.2%) to accurately diagnose malaria as microscopy (61.1%). OptiMAL showed a high level of sensitivity and specificity, compared with microscopy, during both transmission seasons (high & low), with a sensitivity of 92.9% vs. 74.9% and a specificity of 77.2% vs. 87.5%. CONCLUSION: By improving the performance of the test through accurate and continuous quality control of the device in the field, OptiMAL could be suitable for use at CCs for the management and control of malaria.
Journal Article
Low Specificity of a Malaria Rapid Diagnostic Test During an Integrated Community Case Management Trial
by
Tiono, Alfred B
,
Sanon, Souleymane
,
Nébié, Issa
in
Case management
,
Community health care
,
Diagnostic tests
2013
IntroductionParasitological confirmation before administration of antimalarial treatment has been recommended by the World Health Organization in everyone presenting with symptoms suggestive of malaria at all levels of the health system.MethodsThe authors assessed the performance of a histidine-rich protein 2-based malaria rapid diagnostic test used by community health workers in the context of an integrated approach to diagnosis and treatment for malaria and pneumonia. A total of 525 children below 5 years of age were recruited into the study. Children with fever/history of fever within the last 24 h were tested with the rapid diagnostic test (RDT) and a blood smear was obtained for delayed reading.ResultsOverall, the FirstSign™ Malaria Pf (Unimed International Inc, South San Francisco, USA) has shown a high sensitivity profile of 97.9% (95% CI 96.3–98.8), but a low specificity of 53.4% (95% CI 49.1–57.7). The specificity was significantly lower during the high transmission season at 25.4% (95% CI 20.5–31.0) compared to 63.7% (95% CI 57.6–69.4%) at the low transmission season. The negative predictive value (NPV) was 95.4% (95% CI 93.2–96.9) and positive predictive value was 71.7% (95% CI 67.7–75.4). The NPV was significantly higher during the low transmission season at 98.2% (95% CI 95.7–99.3) than compared to 80.0% (95% CI 74.7–84.4) at the high transmission season.ConclusionWith such a low specificity, caution should be exercised when using these RDTs for community case management of malaria.
Journal Article
A systematic review and meta-analysis of the direct epidemiological and economic effects of seasonal influenza vaccination on healthcare workers
by
Stephen B. Lambert
,
Kate Halton
,
Lisa Hall
in
1100 Agricultural and Biological Sciences
,
1300 Biochemistry
,
Absenteeism
2018
Influenza vaccination is a commonly used intervention to prevent influenza infection in healthcare workers (HCWs) and onward transmission to other staff and patients. We undertook a systematic review to synthesize the latest evidence of the direct epidemiological and economic effectiveness of seasonal influenza vaccination among HCW.
We conducted a systematic search of MEDLINE/PubMed, Scopus, and Cochrane Central Register of Controlled Trials from 1980 through January 2018. All studies comparing vaccinated and non-vaccinated (i.e. placebo or non-intervention) groups of HCWs were included. Research articles that focused on only patient-related outcomes or monovalent A(H1N1)pdm09 vaccines were excluded. Two reviewers independently selected articles and extracted data. Pooled-analyses were conducted on morbidity outcomes including laboratory-confirmed influenza, influenza-like illnesses (ILI), and absenteeism. Economic studies were summarized for the characteristics of methods and findings.
Thirteen articles met eligibility criteria: three articles were randomized controlled studies and ten were cohort studies. Pooled results showed a significant effect on laboratory-confirmed influenza incidence but not ILI. While the overall incidence of absenteeism was not changed by vaccine, ILI absenteeism was significantly reduced. The duration of absenteeism was also shortened by vaccination. All published economic evaluations consistently found that the immunization of HCW was cost saving based on crude estimates of avoided absenteeism by vaccination. No studies, however, comprehensively evaluated both health outcomes and costs of vaccination programs to examine cost-effectiveness.
Our findings reinforced the influenza vaccine effects in reducing infection incidence and length of absenteeism. A better understanding of the incidence of absenteeism and comprehensive economic program evaluations are required to ensure the best possible management of ill HCWs and the investment in HCW immunization in increasingly constrained financial environments. These steps are fundamental to establish sustainability and cost-effectiveness of vaccination programs and underpin HCW immunization policy.
Journal Article
Detecting the impact of temperature on transmission of Zika, dengue, and chikungunya using mechanistic models
by
Shocket, Marta S.
,
Gudapati, Prithvi
,
Lippi, Catherine A.
in
Aedes - growth & development
,
Aedes aegypti
,
Aedes albopictus
2017
Recent epidemics of Zika, dengue, and chikungunya have heightened the need to understand the seasonal and geographic range of transmission by Aedes aegypti and Ae. albopictus mosquitoes. We use mechanistic transmission models to derive predictions for how the probability and magnitude of transmission for Zika, chikungunya, and dengue change with mean temperature, and we show that these predictions are well matched by human case data. Across all three viruses, models and human case data both show that transmission occurs between 18-34°C with maximal transmission occurring in a range from 26-29°C. Controlling for population size and two socioeconomic factors, temperature-dependent transmission based on our mechanistic model is an important predictor of human transmission occurrence and incidence. Risk maps indicate that tropical and subtropical regions are suitable for extended seasonal or year-round transmission, but transmission in temperate areas is limited to at most three months per year even if vectors are present. Such brief transmission windows limit the likelihood of major epidemics following disease introduction in temperate zones.
Journal Article