scholarly journals Infection prevalence and density of a pathogenic trematode parasite decrease with stream order along a river continuum

Ecosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Landon P. Falke ◽  
Daniel L. Preston
Keyword(s):  
Infection Prevalence ◽  
Stream Order ◽  
Trematode Parasite ◽  
River Continuum

scholarly journals Spatial pattern of riparian plants along stream order among mountain rivers in China

2018 ◽  
Vol 9 (2) ◽  
pp. 322-330
Author(s):  
Rong Sun ◽  
Xiaojie Luo ◽  
Xiangyu Meng ◽  
Yan Wang
Keyword(s):  
Species Richness ◽  
Environmental Factors ◽  
Tree Species ◽  
Riparian Vegetation ◽  
Stream Order ◽  
River Continuum ◽  
Riparian Plants ◽  
Tree Species Richness ◽  
Riparian Species ◽  
Significant Difference

Abstract The streams in a watershed form a hierarchical network system. From the perspective of the river continuum, this classification system is the result of gradual increase in traffic. This study analyzed the riparian species richness, diversity and environmental factors along a six-order hierarchical mountain river in the Donghe watershed, China. A total of 34 sampling sites were sampled to study the spatial distribution of riparian plants among different stream orders. The results showed: Environmental factors among stream orders had significant differences. Among stream order, species richness showed remarkable differences. The species richness rose firstly and dropped afterwards except for tree species richness; tree species richness decreased while stream order increased. The same is true for shrub quadrat species richness. Shannon-Wiener diversity, Simpson dominance and Pielou uniformity showed significant difference among stream orders; Shannon-Wiener diversity rose firstly then dropped afterwards. For integrated environmental factors and community characteristics, we found the changes of stream orders had a significant impact on riparian habitats and riparian vegetation. Further analysis showed that riparian vegetation experienced different types and degrees of disturbance in different stream orders. This meant that a hierarchical management strategy should be applied to riparian vegetation management.

scholarly journals A Randomized Controlled Trial of Isoniazid to Prevent Mycobacterium tuberculosis Infection in Kenyan Human Immunodeficiency Virus–Exposed Uninfected Infants

2020 ◽  
Author(s):  
Sylvia M LaCourse ◽  
Barbra A Richardson ◽  
John Kinuthia ◽  
A J Warr ◽  
Elizabeth Maleche-Obimbo ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Mycobacterium Tuberculosis ◽  
High Risk ◽  
Adverse Events ◽  
Controlled Trial ◽  
Preventive Therapy ◽  
Infection Prevalence ◽  
Mycobacterium Tuberculosis Infection ◽  
Immunodeficiency Virus ◽  
Exposed Uninfected

Abstract Background Human immunodeficiency virus (HIV)–exposed uninfected (HEU) infants in endemic settings are at high risk of tuberculosis (TB). For infants, progression from primary Mycobacterium tuberculosis (Mtb) infection to TB disease can be rapid. We assessed whether isoniazid (INH) prevents primary Mtb infection. Methods We conducted a randomized nonblinded controlled trial enrolling HEU infants 6 weeks of age without known TB exposure in Kenya. Participants were randomized (1:1) to 12 months of daily INH (10 mg/kg) vs no INH. Primary endpoint was Mtb infection at end of 12 months, assessed by interferon-γ release assay (QuantiFERON-TB Gold Plus) and/or tuberculin skin test (TST, added 6 months after first participant exit). Results Between 15 August 2016 and 6 June 2018, 416 infants were screened, with 300 (72%) randomized to INH or no INH (150 per arm); 2 were excluded due to HIV infection. Among 298 randomized HEU infants, 12-month retention was 96.3% (287/298), and 88.9% (265/298) had primary outcome data. Mtb infection prevalence at 12-month follow-up was 10.6% (28/265); 7.6% (10/132) in the INH arm and 13.5% (18/133) in the no INH arm (7.0 vs 13.4 per 100 person-years; hazard ratio, 0.53 [95% confidence interval {CI}, .24–1.14]; P = .11]), and driven primarily by TST positivity (8.6% [8/93] in INH and 18.1% [17/94] in no INH; relative risk, 0.48 [95% CI, .22–1.05]; P = .07). Frequency of severe adverse events was similar between arms (INH, 14.0% [21/150] vs no INH, 10.7% [16/150]; P = .38), with no INH-related adverse events. Conclusions Further studies evaluating TB preventive therapy to prevent or delay primary Mtb infection in HEU and other high-risk infants are warranted. Clinical Trials Registration NCT02613169.

Natural and anthropogenic impacts on the DOC characteristics in the Yellow River continuum

2021 ◽  
pp. 117231
Author(s):  
Zhidan Wen ◽  
Kaishan Song ◽  
Yingxin Shang ◽  
Lili Lyu ◽  
Hui Tao ◽  
...  
Keyword(s):  
Yellow River ◽  
Anthropogenic Impacts ◽  
The Yellow River ◽  
River Continuum

scholarly journals Predicting the Presence of Leptospires in Rodents from Environmental Indicators Opens Up Opportunities for Environmental Monitoring of Human Leptospirosis

2021 ◽  
Vol 13 (2) ◽  
pp. 325
Author(s):  
Leon Biscornet ◽  
Christophe Révillion ◽  
Sylvaine Jégo ◽  
Erwan Lagadec ◽  
Yann Gomard ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Environmental Factors ◽  
Control Strategies ◽  
Sampling Site ◽  
Rattus Rattus ◽  
Environmental Parameters ◽  
Environmental Indicators ◽  
Small Island ◽  
Urban Landscapes ◽  
Infection Prevalence

Leptospirosis, an environmental infectious disease of bacterial origin, is the infectious disease with the highest associated mortality in Seychelles. In small island territories, the occurrence of the disease is spatially heterogeneous and a better understanding of the environmental factors that contribute to the presence of the bacteria would help implement targeted control. The present study aimed at identifying the main environmental parameters correlated with animal reservoirs distribution and Leptospira infection in order to delineate habitats with highest prevalence. We used a previously published dataset produced from a large collection of rodents trapped during the dry and wet seasons in most habitats of Mahé, the main island of Seychelles. A land use/land cover analysis was realized in order to describe the various environments using SPOT-5 images by remote sensing (object-based image analysis). At each sampling site, landscape indices were calculated and combined with other geographical parameters together with rainfall records to be used in a multivariate statistical analysis. Several environmental factors were found to be associated with the carriage of leptospires in Rattus rattus and Rattus norvegicus, namely low elevations, fragmented landscapes, the proximity of urbanized areas, an increased distance from forests and, above all, increased precipitation in the three months preceding trapping. The analysis indicated that Leptospira renal carriage could be predicted using the species identification and a description of landscape fragmentation and rainfall, with infection prevalence being positively correlated with these two environmental variables. This model may help decision makers in implementing policies affecting urban landscapes and/or in balancing conservation efforts when designing pest control strategies that should also aim at reducing human contact with Leptospira-laden rats while limiting their impact on the autochthonous fauna.

scholarly journals SARS-CoV-2 infection is at herd immunity in the majority segment of the population of Qatar

2021 ◽  
Author(s):  
Mohamed H Al-Thani ◽  
Elmoubasher Farag ◽  
Roberto Bertollini ◽  
Hamad Eid Al Romaihi ◽  
Sami Abdeen ◽  
...  
Keyword(s):  
Total Population ◽  
Herd Immunity ◽  
Geographic Location ◽  
Population Based ◽  
Infection Prevalence ◽  
Cross Sectional ◽  
Previous Infection ◽  
Current Infection ◽  
Polymerase Chain ◽  
Population Based Survey

Abstract Background Qatar experienced a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic that disproportionately affected the craft and manual worker (CMW) population who comprise 60% of the total population. This study aimed to assess ever and/or current infection prevalence in this population. Methods A cross-sectional population-based survey was conducted during July 26-September 09, 2020 to assess both anti-SARS-CoV-2 positivity through serological testing and current infection positivity through polymerase chain reaction (PCR) testing. Associations with antibody and PCR positivity were identified through regression analyses. Results Study included 2,641 participants, 69.3% of whom were <40 years of age. Anti-SARS-CoV-2 positivity was 55.3% (95% CI: 53.3-57.3%) and was significantly associated with nationality, geographic location, educational attainment, occupation, and previous infection diagnosis. PCR positivity was 11.3% (95% CI: 9.9-12.8%) and was significantly associated with nationality, geographic location, occupation, contact with an infected person, and reporting two or more symptoms. Infection positivity (antibody and/or PCR positive) was 60.6% (95% CI: 58.6-62.5%). The proportion of antibody-positive CMWs that had a prior SARS-CoV-2 diagnosis was 9.3% (95% CI: 7.9-11.0%). Only seven infections were ever severe and one was ever critical—an infection severity rate of 0.5% (95% CI: 0.2-1.0%). Conclusions Six in every 10 CMWs have been infected, suggestive of reaching the herd immunity threshold. Infection severity was low with only one in every 200 infections progressing to be severe or critical. Only one in every 10 infections had been previously diagnosed suggestive of mostly asymptomatic or mild infections.

scholarly journals Spatial and temporal patterns of the emerging tick-borne pathogen Borrelia miyamotoi in blacklegged ticks (Ixodes scapularis) in New York

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
F. Keesing ◽  
D. J. McHenry ◽  
M. H. Hersh ◽  
R. S. Ostfeld
Keyword(s):  
New York ◽  
Ixodes Scapularis ◽  
Quantitative Polymerase Chain Reaction ◽  
Human Infection ◽  
Ixodid Ticks ◽  
Transovarial Transmission ◽  
Infection Prevalence ◽  
Borrelia Miyamotoi ◽  
Spatial And Temporal Patterns ◽  
Reservoir Hosts

AbstractBorrelia miyamotoi, a bacterium that causes relapsing fever, is found in ixodid ticks throughout the northern hemisphere. The first cases of human infection with B. miyamotoi were identified in 2011. In the eastern USA, blacklegged ticks (Ixodes scapularis) become infected by feeding on an infected vertebrate host, or through transovarial transmission. We surveyed B. miyamotoi prevalence in ticks within forested habitats in Dutchess County, New York, and identified possible reservoir hosts. To assess spatial variation in infection, we collected questing nymphal ticks at > 150 sites. To assess temporal variation in infection, we collected questing nymphs for 8 years at a single study site. We collected questing larval ticks from nine plots to estimate the amount of transovarial transmission. To evaluate potential reservoir hosts, we captured 14 species of mammal and bird hosts naturally infested with larval blacklegged ticks and held these hosts in the laboratory until ticks fed to repletion and molted to nymphs. We determined infection for all ticks using quantitative polymerase chain reaction. The overall infection prevalence of questing nymphal ticks across all sites was ~ 1%, but prevalence at individual sites was as high as 9.1%. We detected no significant increase in infection through time. Only 0.4% of questing larval ticks were infected. Ticks having fed as larvae from short-tailed shrews, red squirrels, and opossums tended to have higher infection prevalence than did ticks having fed on other hosts. Further studies of the role of hosts in transmission are warranted. The locally high prevalence of B. miyamotoi in the New York/New England landscape suggests the importance of vigilance by health practitioners and the public.

scholarly journals Mental health, compliance with measures and health prospects during the COVID-19 epidemic: the role of health literacy

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lize Hermans ◽  
Stephan Van den Broucke ◽  
Lydia Gisle ◽  
Stefaan Demarest ◽  
Rana Charafeddine
Keyword(s):  
Mental Health ◽  
At Risk ◽  
Health Literacy ◽  
Prevalence Ratio ◽  
Physical Distance ◽  
Poor Mental Health ◽  
Infection Prevalence ◽  
Cross Sectional ◽  
Normal Life ◽  
Low Health Literacy

Abstract Background The importance of health literacy in dealing with the COVID-19 epidemic has been emphasized but scarcely addressed empirically. In this study, the association of health literacy with mental health, compliance with COVID-19 preventive measures and health prospects was assessed in a Belgian context. Methods Data were extracted from the third of a series of cross-sectional online COVID-related surveys (n = 32,794). Data collection took place for 1 week starting the 28th of May 2020. People residing in Belgium and aged 18 years or older could participate. Data were collected on sociodemographic background, health literacy, multimorbidity, mental health (depression, anxiety, sleeping disorder, vitality), knowledge about COVID-19, compliance with COVID-19 measures (hygiene, physical distance, covering mouth and nose on public transport and in places where physical distance cannot be respected), and health prospects (risk for health when returning to normal life and possibility of infection). Prevalence Ratio (PR) of poor mental health, non-compliance with the measures and health prospects in relation to health literacy were calculated using Poisson regressions. Results People showing sufficient health literacy were less likely to suffer from anxiety disorders (PR = 0.47, 95% CI = [0.42–0.53]), depression (PR = 0.46, 95% CI = [0.40–0.52]) and sleeping disorders (PR = 0.85, 95% CI = [0.82–0.87]), and more likely to have optimal vitality (PR = 2.41, 95% CI = [2.05–2.84]) than people with low health literacy. They were less at risk of not complying with the COVID-19 measures (PR between 0.60 and 0.83) except one (covering mouth and nose in places where physical distance cannot be respected). Finally, they were less likely to perceive returning to normal life as threatening (PR = 0.70, 95% CI = [0.65–0.77]) and to consider themselves at risk of an infection with COVID-19 (PR = 0.75, 95% CI = [0.67–0.84]). The associations remained significant after controlling for COVID-19 knowledge and multimorbidity. Conclusions These results suggest that health literacy is a crucial factor in managing the COVID-19 epidemic and offer a perspective for future studies that target health literacy in the context of virus outbreaks.

scholarly journals Invasive Burmese pythons alter host use and virus infection in the vector of a zoonotic virus

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Nathan D. Burkett-Cadena ◽  
Erik M. Blosser ◽  
Anne A. Loggins ◽  
Monica C. Valente ◽  
Maureen T. Long ◽  
...  
Keyword(s):  
Biological Diversity ◽  
Dilution Effect ◽  
Transmission Risk ◽  
Infection Prevalence ◽  
Host Use ◽  
Invasive Predator ◽  
Cotton Rats ◽  
Generalized Linear Mixed Effects ◽  
Python Bivittatus ◽  
Southern Florida

AbstractThe composition of wildlife communities can have strong effects on transmission of zoonotic vector-borne pathogens, with more diverse communities often supporting lower infection prevalence in vectors (dilution effect). The introduced Burmese python, Python bivittatus, is eliminating large and medium-sized mammals throughout southern Florida, USA, impacting local communities and the ecology of zoonotic pathogens. We investigated invasive predator-mediated impacts on ecology of Everglades virus (EVEV), a zoonotic pathogen endemic to Florida that circulates in mosquito-rodent cycle. Using binomial generalized linear mixed effects models of field data at areas of high and low python densities, we show that increasing diversity of dilution host (non-rodent mammals) is associated with decreasing blood meals on amplifying hosts (cotton rats), and that increasing cotton rat host use is associated with increasing EVEV infection in vector mosquitoes. The Burmese python has caused a dramatic decrease in mammal diversity in southern Florida, which has shifted vector host use towards EVEV amplifying hosts (rodents), resulting in an indirect increase in EVEV infection prevalence in vector mosquitoes, putatively elevating human transmission risk. Our results indicate that an invasive predator can impact wildlife communities in ways that indirectly affect human health, highlighting the need for conserving biological diversity and natural communities.

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