High prevalence of Plasmodium falciparum gametocyte infections in school-age children using molecular detection: patterns and predictors of risk from a cross-sectional study in southern Malawi

Abstract Background In endemic areas, many people experience asymptomatic Plasmodium infections, particularly older children and adults, but their transmission contribution is unknown. Though not the exclusive determinant of infectiousness, transmission from humans to mosquitoes requires blood meals containing gametocytes. Gametocytes often occur at submicroscopic densities, challenging measurement in human populations. More sensitive molecular techniques allow better characterization of gametocyte epidemiologic patterns. Methods Approximately 30 households were selected from each of eight sites in southern Malawi during two cross-sectional surveys. Blood was sampled from 623 people during the dry season and 896 the following rainy season. Among people PCR-positive for Plasmodium falciparum, mature gametocytes were detected by qRT-PCR. Regression models evaluated predictors of gametocyte carriage and density in the total population and among those with PCR-positive infections. Results The prevalence of gametocyte carriage by molecular testing was 3.5% during the dry season and 8.6% during the rainy season, and by microscopy 0.8 and 3.3%, respectively. Nearly half of PCR-positive infections carried gametocytes, regardless of recent symptom status. Among P. falciparum-infected people, only living in unfinished houses and age were significantly associated with gametocyte presence. Infected people in unfinished houses had higher odds of carrying gametocytes (OR 2.24, 95% CI 1.16–4.31), and 31% (95% CI 3–65%) higher gametocyte density than those in finished houses. School-age children (5–15 years), had higher odds than adults (≥16 years) of having gametocytes when infected (OR 2.77, 95% CI 1.47–5.19), but 31% (95% CI 11–47%) lower gametocyte density. Children <5 years did not have significantly higher odds of gametocyte carriage or density when infected than adults. Conclusions School-age children frequently carry gametocytes in communities of southern Malawi and represent an under-recognized reservoir of infection. Malaria elimination strategies should address these frequently asymptomatic reservoirs, especially in highly endemic areas. Improved household construction may also reduce the infectious reservoir.http://deepblue.lib.umich.edu/bitstream/2027.42/134670/1/12936_2016_Article_1587.pd

Insecticide-treated net effectiveness at preventing Plasmodium falciparum infection varies by age and season

Abstract Background After increasing coverage of malaria interventions, malaria prevalence remains high in Malawi. Previous studies focus on the impact of malaria interventions among children under 5 years old. However, in Malawi, the prevalence of infection is highest in school-aged children (SAC), ages 5 to 15 years. This study examined the interaction between age group and insecticide-treated net (ITN) use for preventing individual and community-level infection in Malawi. Methods Six cross-sectional surveys were conducted in the rainy and dry seasons in southern Malawi from 2012 to 2014. Data were collected on household ITN usage and demographics. Blood samples for detection of Plasmodium falciparum infection were obtained from all household members present and over 6 months of age. Generalized linear mixed models were used to account for clustering at the household and community level. Results There were 17,538 observations from six surveys. The association between ITN use and infection varied by season in SAC, but not in other age groups. The adjusted odds ratio (OR) for infection comparing ITN users to non-users among SAC in the rainy season and dry season was 0.78 (95% CI 0.56, 1.10) and 0.51 (0.35, 0.74), respectively. The effect of ITN use did not differ between children under five and adults. Among all non-SACs the OR for infection was 0.78 (0.64, 0.95) in those who used ITNs compared to those that did not. Community net use did not protect against infection. Conclusions Protection against infection with ITN use varies by age group and season. Individual estimates of protection are moderate and a community-level effect was not detected. Additional interventions to decrease malaria prevalence are needed in Malawi.http://deepblue.lib.umich.edu/bitstream/2027.42/135726/1/12936_2017_Article_1686.pd

A Randomized Trial to Compare a Tailored Web-Based Intervention and Tailored Phone Counseling to Usual Care for Increasing Colorectal Cancer Screening

Background: Colorectal cancer mortality could be decreased with risk-appropriate cancer screening. We examined the efficacy of three tailored interventions compared with usual care for increasing screening adherence. Methods: Women (n = 1,196) ages 51 to 74, from primary care networks and nonadherent to colorectal cancer guidelines, were randomized to (1) usual care, (2) tailored Web intervention, (3) tailored phone intervention, or (4) tailored Web + phone intervention. Average-risk women could select either stool test or colonoscopy, whereas women considered at higher than average risk received an intervention that supported colonoscopy. Outcome data were collected at 6 months by self-report, followed by medical record confirmation (attrition of 23%). Stage of change for colorectal cancer screening (precontemplation or contemplation) was assessed at baseline and 6 months. Results: The phone (41.7%, P < 0.0001) and combined Web + phone (35.8%, P < 0.001) interventions significantly increased colorectal cancer screening by stool test compared with usual care (11.1%), with ORs ranging from 5.4 to 6.8 in models adjusted for covariates. Colonoscopy completion did not differ between groups except that phone significantly increased colonoscopy completion compared with usual care for participants in the highest tertile of self-reported fear of cancer. Conclusions: A tailored phone with or without a Web component significantly increased colorectal cancer screening compared with usual care, primarily through stool testing, and phone significantly increased colonoscopy compared with usual care but only among those with the highest levels of baseline fear. Impact: This study supports tailored phone counseling with or without a Web program for increasing colorectal cancer screening in average-risk women

Spatial correlation of aftershock locations and on-fault main shock properties

[1] We quantify the correlation between spatial patterns of aftershock hypocenter locations and the distribution of coseismic slip and stress drop on a main shock fault plane using two nonstandard statistical tests. Test T1 evaluates if aftershock hypocenters are located in low‐slip regions (hypothesis H1), test T2 evaluates if aftershock hypocenters occur in regions of increased shear stress (hypothesis H2). In the tests, we seek to reject the null hypotheses H0: Aftershock hypocenters are not correlated with (1) low‐slip regions or (2) regions of increased shear stress, respectively. We tested the hypotheses on four strike‐slip events for which multiple earthquake catalogs and multiple finite fault source models of varying accuracy exist. Because we want to retain earthquake clustering as the fundamental feature of aftershock seismicity, we generate slip distributions using a random spatial field model and derive the stress drop distributions instead of generating seismicity catalogs. We account for uncertainties in the aftershock locations by simulating them within their location error bounds. Our findings imply that aftershocks are preferentially located in regions of low‐slip (u ≤ equation imageu max) and of increased shear stress (Δσ < 0). In particular, the correlation is more significant for relocated than for general network aftershock catalogs. However, the results show that stress drop patterns provide less information content on aftershock locations. This implies that static shear stress change of the main shock may not be the governing process for aftershock genesis.ISSN:2169-9313ISSN:0148-0227ISSN:2169-935

Pregnancy outcomes and risk of placental malaria after artemisinin-based and quinine-based treatment for uncomplicated falciparum malaria in pregnancy: a WorldWide Antimalarial Resistance Network systematic review and individual patient data meta-analysis.

Malaria in pregnancy, including asymptomatic infection, has a detrimental impact on foetal development. Individual patient data (IPD) meta-analysis was conducted to compare the association between antimalarial treatments and adverse pregnancy outcomes, including placental malaria, accompanied with the gestational age at diagnosis of uncomplicated falciparum malaria infection. A systematic review and one-stage IPD meta-analysis of studies assessing the efficacy of artemisinin-based and quinine-based treatments for patent microscopic uncomplicated falciparum malaria infection (hereinafter uncomplicated falciparum malaria) in pregnancy was conducted. The risks of stillbirth (pregnancy loss at ≥ 28.0 weeks of gestation), moderate to late preterm birth (PTB, live birth between 32.0 and &lt; 37.0 weeks), small for gestational age (SGA, birthweight of &lt; 10th percentile), and placental malaria (defined as deposition of malaria pigment in the placenta with or without parasites) after different treatments of uncomplicated falciparum malaria were assessed by mixed-effects logistic regression, using artemether-lumefantrine, the most used antimalarial, as the reference standard. Registration PROSPERO: CRD42018104013. Of the 22 eligible studies (n = 5015), IPD from16 studies were shared, representing 95.0% (n = 4765) of the women enrolled in literature. Malaria treatment in this pooled analysis mostly occurred in the second (68.4%, 3064/4501) or third trimester (31.6%, 1421/4501), with gestational age confirmed by ultrasound in 91.5% (4120/4503). Quinine (n = 184) and five commonly used artemisinin-based combination therapies (ACTs) were included: artemether-lumefantrine (n = 1087), artesunate-amodiaquine (n = 775), artesunate-mefloquine (n = 965), and dihydroartemisinin-piperaquine (n = 837). The overall pooled proportion of stillbirth was 1.1% (84/4361), PTB 10.0% (619/4131), SGA 32.3% (1007/3707), and placental malaria 80.1% (2543/3035), and there were no significant differences of considered outcomes by ACT. Higher parasitaemia before treatment was associated with a higher risk of SGA (adjusted odds ratio [aOR] 1.14 per 10-fold increase, 95% confidence interval [CI] 1.03 to 1.26, p = 0.009) and deposition of malaria pigment in the placenta (aOR 1.67 per 10-fold increase, 95% CI 1.42 to 1.96, p &lt; 0.001). The risks of stillbirth, PTB, SGA, and placental malaria were not different between the commonly used ACTs. The risk of SGA was high among pregnant women infected with falciparum malaria despite treatment with highly effective drugs. Reduction of malaria-associated adverse birth outcomes requires effective prevention in pregnant women

Homeless women's perspectives on smoking and smoking cessation programs: A qualitative study

BackgroundIndividuals who are unsheltered or experiencing homelessness are more likely to smoke than those in the general population and have a higher prevalence of tobacco-related illnesses. Those who are unhoused make quit attempts at rates similar to the general population, however rates of successful quitting are much lower. Women bear a higher burden of smoking-related diseases and are less successful in their cessation efforts than men. Despite these increased risks and challenges, cessation programs specifically designed to meet the needs of women experiencing homelessness are extremely rare.MethodsTo examine perceptions of smoking cessation programs among women who are unstably housed, we conducted in-depth, semi-structured interviews with twenty-nine women experiencing homelessness or unstable housing who had histories of tobacco and substance use. Interviews explored the social context of smoking, as well as interest in, barriers to, and facilitators of quitting. We used a grounded theory approach to analyze the transcripts.ResultsParticipants reported a number of structural barriers to cessation. They reported obstacles to participating in existing cessation programs, including chronic stress related to experiences of being unsheltered and fear of being exposed to neighborhood violence. These conditions were paired with a strong need to self-isolate in order to maintain personal safety, which runs counter to traditional group-based cessation programs.ConclusionA dissonance exists between current smoking cessation programs and the needs of women who are unsheltered or unstably housed. Alternative cessation treatment delivery models that address extremely high levels of chronic stress violence, and avoidance of group settings are needed, as are programs that provide options for safe participation

Blood-feeding patterns of Anopheles vectors of human malaria in Malawi: implications for malaria transmission and effectiveness of LLIN interventions

Abstract Background Access to human hosts by Anopheles mosquitoes is a key determinant of vectorial capacity for malaria, but it can be limited by use of long-lasting insecticidal nets (LLINs). In Malawi, pyrethroid-treated LLINs with and without the synergist piperonyl butoxide (PBO) were distributed to control malaria. This study investigated the blood-feeding patterns of malaria vectors and whether LLINs containing pyrethroid and PBO led to a reduction of human blood feeding than those containing only pyrethroids. Methods Mosquitoes were sampled inside houses from May 2019 through April 2020 by aspiration, pyrethrum spray catch, and light trap methods in two sites. One site (Namanolo, Balaka district) had LLINs containing only pyrethroids whereas the other (Ntaja, Machinga district) had LLINs with both pyrethroids and PBO. Anopheles species, their blood-meal host, and infection with Plasmodium falciparum were determined using PCR methods. Results A total of 6585 female Anopheles were sampled in 203 houses. Of these, 633 (9.6%) were blood-fed mosquitoes comprising of 279 (44.1%) Anopheles arabiensis, 103 (16.3%) Anopheles gambiae 212 (33.5), Anopheles funestus, 2 (0.3%), Anopheles parensis and 37 (5.8%) were unidentified Anopheles spp. Blood meal hosts were successfully identified for 85.5% (n = 541) of the blood-fed mosquitoes, of which 436 (81.0%) were human blood meals, 28 (5.2%) were goats, 11 (2.0%) were dogs, 60 (11.1%) were mixed goat-human blood meals, 5 (0.9%) were dog–human, and 1 was a mixed dog-goat. Human blood index (fraction of blood meals that were humans) was significantly higher in Namanolo (0.96) than Ntaja (0.89). Even though human blood index was high, goats were over-selected than humans after accounting for relative abundance of both hosts. The number of infectious Anopheles bites per person-year was 44 in Namanolo and 22 in Ntaja. Conclusion Although LLINs with PBO PBO may have reduced human blood feeding, access to humans was extremely high despite high LLIN ownership and usage rates in both sites. This finding could explain persistently high rates of malaria infections in Malawi. However, this study had one village for each net type, thus the observed differences may have been a result of other factors present in each village.http://deepblue.lib.umich.edu/bitstream/2027.42/173705/1/12936_2022_Article_4089.pd

Violence and Emergency Department Use among Community-Recruited Women Who Experience Homelessness and Housing Instability.

Women who experience housing instability are at high risk for violence and have disproportionately high rates of emergency department (ED) use. However, little has been done to characterize the violence they experience, or to understand how it may be related to ED use. We recruited homeless and unstably housed women from San Francisco shelters, free meal programs, and single room occupancy (SRO) hotels. We used generalized estimating equations to examine associations between violence and any ED use (i.e., an ED visit for any stated reason) every 6 months for 3 years. Among 300 participants, 44% were African-American, and the mean age was 48 years. The prevalence of violence experienced in the prior 6 months included psychological violence (87%), physical violence without a weapon (48%), physical violence with a weapon (18%), and sexual violence (18%). While most participants (85%) who experienced physical violence with a weapon or sexual violence in the prior 6 months had not visited an ED, these were the only two violence types significantly associated with ED use when all violence types were included in the same model (ORphysical/weapon = 1.83, 95% CI 1.02-3.28; ORsexual = 2.15, 95% CI 1.30-3.53). Only violence perpetrated by someone who was not a primary intimate partner was significantly associated with ED use when violence was categorized by perpetrator. The need to reduce violence in this population is urgent. In the context of health care delivery, policies to facilitate trauma-informed ED care and strategies that increase access to non-ED care, such as street-based medicine, could have substantial impact on the health of women who experience homelessness and housing instability