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The American Journal of Tropical... Aug 2017Almost all human infections by avian influenza viruses (AIVs) are transmitted from poultry. A systematic review was conducted to identify practices associated with human... (Meta-Analysis)
Meta-Analysis Review
Almost all human infections by avian influenza viruses (AIVs) are transmitted from poultry. A systematic review was conducted to identify practices associated with human infections, their prevalence, and rationale. Observational studies were identified through database searches. Meta-analysis produced combined odds ratio estimates. The prevalence of practices and rationales for their adoptions were reported. Of the 48,217 records initially identified, 65 articles were included. Direct and indirect exposures to poultry were associated with infection for all investigated viral subtypes and settings. For the most frequently reported practices, association with infection seemed stronger in markets than households, for sick and dead than healthy poultry, and for H7N9 than H5N1. Practices were often described in general terms and their frequency and intensity of contact were not provided. The prevalence of practices was highly variable across studies, and no studies comprehensively explored reasons behind the adoption of practices. Combining epidemiological and targeted anthropological studies would increase the spectrum and detail of practices that could be investigated and should aim to provide insights into the rationale(s) for their existence. A better understanding of these rationales may help to design more realistic and acceptable preventive public health measures and messages.
Topics: Animals; Humans; Influenza in Birds; Influenza, Human; Poultry; Prevalence; Zoonoses
PubMed: 28749769
DOI: 10.4269/ajtmh.17-0014 -
Water Research X Jan 2024Influenza, a highly contagious acute respiratory disease, remains a major global health concern. This study aimed to comprehensively assess the prevalence of influenza... (Review)
Review
Influenza, a highly contagious acute respiratory disease, remains a major global health concern. This study aimed to comprehensively assess the prevalence of influenza virus in different aquatic environments. Using 43 articles from four databases, we thoroughly examined water matrices from wastewater treatment plants (WTPs) and other human environments, as well as poultry habitats and areas frequented by migratory wild birds. In WTP influents (10 studies), positivity rates for influenza A ranged from 0.0 % to 97.6 %. For influenza B (8 studies), most studies reported no positivity, except for three studies reporting detection in 0.8 %, 5.6 %, and 46.9 % of samples. Within poultry habitats (13 studies), the prevalence of influenza A ranged from 4.3 % to 76.4 %, while in environments frequented by migratory wild birds (11 studies), it ranged from 0.4 % to 69.8 %. Geographically, the studies were distributed as follows: 39.5 % from the Americas, 18.6 % from Europe, 2.3 % from South-East Asia and 39.5 % from the Western Pacific. Several influenza A subtypes were found in water matrices, including avian influenza (H3N6, H3N8, H4N1, H4N2, H4N6, H4N8, H5N1, H5N8, H6N2, H6N6, H7N9, H0N8, and H11N9) and seasonal human influenza (H1N1 and H3N2). The existing literature indicates a crucial requirement for more extensive future research on this topic. Specifically, it emphasizes the need for method harmonization and delves into areas deserving of in-depth research, such as water matrices pertaining to pig farming and prevalence studies in low-income countries.
PubMed: 38298332
DOI: 10.1016/j.wroa.2023.100210 -
PloS One 2014Little is known about risk factors for severe outcomes in patients infected with H5N1 and no systematic review has been conducted. Understanding risk factors is an... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Little is known about risk factors for severe outcomes in patients infected with H5N1 and no systematic review has been conducted. Understanding risk factors is an important step for prioritizing prophylaxis or treatment in the event of a pandemic.
OBJECTIVES
To systematically evaluate risk factors for severe outcomes in patients with avian influenza H5N1 infection.
DATA SOURCES
MEDLINE, EMBASE, CINAHL, GlobalHealth, and CENTRAL through March 2011.
ELIGIBILITY CRITERIA FOR SELECTING STUDIES
Observational studies of any design published in English, French, Spanish, German or Korean that reported on risk factor-outcome combinations of interest in participants with confirmed H5N1 infections. Outcomes considered included death, ventilator support, hospital and ICU admission, pneumonia, and composite outcomes.
STUDY APPRAISAL
Risk of bias was assessed using the Newcastle-Ottawa scale (NOS).
RESULTS
We identified 20 studies reporting on 999 patients infected with H5N1. The majority of studies (n = 14, 70%) were at intermediate risk of bias, i.e. 4-6 points on the NOS. Females were at increased risk of death (OR 1.75, 95% CI 1.27-2.44), while young age, in particular <5 years of age (OR 0.44, 95% CI 0.25-0.79 for death), was protective. Data on traditional risk factors was scarce and requires further studies. Another major limitation in the published literature was lack of adjustment for confounders.
INTERPRETATION
Females were at increased risk for complications following H5N1 infection while young age protected against severe outcomes. Research on traditional risk factors was limited and is required.
Topics: Animals; Birds; Female; Host-Pathogen Interactions; Humans; Influenza A Virus, H5N1 Subtype; Influenza in Birds; Influenza, Human; Risk Factors; Sex Factors
PubMed: 24603885
DOI: 10.1371/journal.pone.0089697 -
Viruses Sep 2020In the recent past, sub-Saharan Africa has not escaped the devastating effects of avian influenza virus (AIV) in poultry and wild birds. This systematic review describes... (Meta-Analysis)
Meta-Analysis
In the recent past, sub-Saharan Africa has not escaped the devastating effects of avian influenza virus (AIV) in poultry and wild birds. This systematic review describes the prevalence, spatiotemporal distribution, and virus subtypes detected in domestic and wild birds for the past two decades (2000-2019). We collected data from three electronic databases, PubMed, SpringerLink electronic journals and African Journals Online, using the Preferred Reporting Items for Systematic reviews and Meta-Analyses protocol. A total of 1656 articles were reviewed, from which 68 were selected. An overall prevalence of 3.0% AIV in birds was observed. The prevalence varied between regions and ranged from 1.1% to 7.1%. The Kruskal-Wallis and Wilcoxon signed-rank sum test showed no significant difference in the prevalence of AIV across regions, χ(3) = 5.237, = 0.1553 and seasons, T = 820, z = -1.244, = 0.2136. Nineteen hemagglutinin/neuraminidase subtype combinations were detected during the reviewed period, with southern Africa recording more diverse AIV subtypes than other regions. The most detected subtype was H5N1, followed by H9N2, H5N2, H5N8 and H6N2. Whilst these predominant subtypes were mostly detected in domestic poultry, H1N6, H3N6, H4N6, H4N8, H9N1 and H11N9 were exclusively detected in wild birds. Meanwhile, H5N1, H5N2 and H5N8 were detected in both wild and domestic birds suggesting circulation of these subtypes among wild and domestic birds. Our findings provide critical information on the eco-epidemiology of AIVs that can be used to improve surveillance strategies for the prevention and control of avian influenza in sub-Saharan Africa.
Topics: Africa, Southern; Animals; Animals, Wild; Birds; Influenza A virus; Influenza in Birds; Phylogeny; Poultry; Poultry Diseases
PubMed: 32906666
DOI: 10.3390/v12090993 -
BMC Medicine Dec 2020Highly pathogenic avian influenza A(H5N1) virus poses a global public health threat given severe and fatal zoonotic infections since 1997 and ongoing A(H5N1) virus... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Highly pathogenic avian influenza A(H5N1) virus poses a global public health threat given severe and fatal zoonotic infections since 1997 and ongoing A(H5N1) virus circulation among poultry in several countries. A comprehensive assessment of the seroprevalence of A(H5N1) virus antibodies remains a gap and limits understanding of the true risk of A(H5N1) virus infection.
METHODS
We conducted a systematic review and meta-analysis of published serosurveys to assess the risk of subclinical and clinically mild A(H5N1) virus infections. We assessed A(H5N1) virus antibody titers and changes in titers among populations with variable exposures to different A(H5N1) viruses.
RESULTS
Across studies using the World Health Organization-recommended seropositive definition, the point estimates of the seroprevalence of A(H5N1) virus-specific antibodies were higher in poultry-exposed populations (range 0-0.6%) and persons exposed to both human A(H5N1) cases and infected birds (range 0.4-1.8%) than in close contacts of A(H5N1) cases or the general population (none to very low frequencies). Seroprevalence was higher in persons exposed to A(H5N1) clade 0 virus (1.9%, range 0.7-3.2%) than in participants exposed to other clades of A(H5N1) virus (range 0-0.5%) (p < 0.05). Seroprevalence was higher in poultry-exposed populations (range 0-1.9%) if such studies utilized antigenically similar A(H5N1) virus antigens in assays to A(H5N1) viruses circulating among poultry.
CONCLUSIONS
These low seroprevalences suggest that subclinical and clinically mild human A(H5N1) virus infections are uncommon. Standardized serological survey and laboratory methods are needed to fully understand the extent and risk of human A(H5N1) virus infections.
Topics: Animals; Birds; Humans; Influenza A Virus, H5N1 Subtype; Influenza in Birds; Influenza, Human; Seroepidemiologic Studies; Zoonoses
PubMed: 33261599
DOI: 10.1186/s12916-020-01836-y -
Microbial Pathogenesis Oct 2019Avian influenza viruses (AIVs) in wild birds pose a pandemic threat to humans and to the poultry industry. To assess AIV and AIV antibody prevalence in wild birds in... (Meta-Analysis)
Meta-Analysis
Avian influenza viruses (AIVs) in wild birds pose a pandemic threat to humans and to the poultry industry. To assess AIV and AIV antibody prevalence in wild birds in China, a systematic review and meta-analysis were conducted. We searched PubMed, Google Scholar, Cochrane Library, Clinical Trial, VIP, CNKI, and WANFANG for published papers related to the prevalence of AIVs and their associated antibodies in wild birds in China from Mar. 10, 2005 to Sept. 20, 2018. Repeat studies, reviews, and other host studies were excluded, as well as those with inconsistent data, incomplete information, or only prevalence data or data from outside of mainland China. In total, data from 28 publications were compiled and analyzed. Based on out meta-analysis, the pooled prevalence of AIVs in wild birds in China was found to be 2.5% (571/23,024), and the pooled prevalence of AIV antibodies was 26.5% (1,210/4,566). The pooled prevalence of AIVs was significantly higher in wild birds from Central China (5.5%, 271/4, 955) compared to all other regions and the pooled prevalence of AIV antibodies was significantly in wild birds from South China (56.8%, 92/162) in comparison to all other regions. The prevalence of both AIVs and AIV antibodies in Anseriformes were higher compared to non-Anseriformes. In addition, the largest number of studies found in this review were on the HA subtypes of AIVs (H5, H7, and H9) and their associated antibodies. In summary, our findings suggest that the prevalence of AIVs and their antibodies in wild birds vary among regions and species of wild bird. Thus, further monitoring of the prevalence of AIVs and their antibodies in wild birds in China is necessary and should be used for guiding powerful and effective regulatory measures that will prevent the spread of AIVs across species.
Topics: Animals; Animals, Wild; Antibodies; Birds; China; Databases, Factual; Influenza A virus; Influenza in Birds; Pandemics; Prevalence
PubMed: 31254602
DOI: 10.1016/j.micpath.2019.103613 -
PloS One 2017The emergence of the 2009 influenza pandemic virus with a swine origin stressed the importance of improving influenza surveillance in swine populations. The objectives... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The emergence of the 2009 influenza pandemic virus with a swine origin stressed the importance of improving influenza surveillance in swine populations. The objectives of this systematic review and meta-analysis were to describe epidemiological features of swine influenza (SI) across the world and identify factors impacting swine influenza virus surveillance.
METHODS
The systematic review followed the PRISMA guidelines. Articles published after 1990 containing data on SI on pig and herd-level seroprevalence, isolation and detection rates, and risk factors were included. Meta-regression analyses using seroprevalence and virological rates were performed.
RESULTS
A total of 217 articles were included. Low avian influenza (AI) seroprevalence (means pig = 4.1%; herd = 15%) was found, showing that AIV do not readily establish themselves in swine while SIV seroprevalence was usually high across continents (influenza A means pig = 32.6-87.8%; herd = 29.3-100%). Higher pig density and number of pigs per farm were shown by the meta-regression analyses and/or the risk factor articles to be associated with higher SI seroprevalence. Lower seroprevalence levels were observed for countries with low-to-medium GDP. These results suggest that larger industrial farms could be more at risk of SIV circulation. Sampling swine with influenza-like illness (ILI) was positively associated with higher isolation rates; most studies in Europe, Latin and North America were targeting swine with ILI.
CONCLUSIONS
To improve understanding of SI epidemiology, standardization of the design and reporting of SI epidemiological studies is desirable. Performance of SI surveillance systems in low-to-medium GDP countries should be evaluated to rule out technical issues linked to lower observed SIV prevalence. Targeting certain swine age groups, farming systems and swine with ILI may improve the surveillance cost-effectiveness. However, focusing on pigs with ILI may bias virus detection against strains less virulent for swine but which may be important as pandemic threats.
Topics: Animals; Europe; Humans; Influenza A Virus, H1N1 Subtype; Influenza, Human; North America; Orthomyxoviridae Infections; Seroepidemiologic Studies; Swine; Swine Diseases; Zoonoses
PubMed: 28591202
DOI: 10.1371/journal.pone.0179044 -
Microbial Pathogenesis Mar 2023The zoonotic pathogen avian influenza A H5N8 causes enormous economic losses in the poultry industry and poses a serious threat to the public health. Here, we report the... (Meta-Analysis)
Meta-Analysis
The zoonotic pathogen avian influenza A H5N8 causes enormous economic losses in the poultry industry and poses a serious threat to the public health. Here, we report the first systematic review and meta-analysis of the worldwide prevalence of birds. We filtered 45 eligible articles from seven databases. A random-effects model was used to analyze the prevalence of H5N8 in birds. The pooled prevalence of H5N8 in birds was 1.6%. In the regions, Africa has the highest prevalence (8.0%). Based on the source, village (8.3%) was the highest. In the sample type, the highest prevalence was organs (79.7%). In seasons, the highest prevalence was autumn (28.1%). The largest prevalence in the sampling time was during 2019 or later (7.0%). Furthermore, geographical factors also were associated with the prevalence. Therefore, we recommend site-specific prevention and control tools for this strain in birds and enhance the surveillance to reduce the spread of H5N8.
Topics: Animals; Humans; Influenza in Birds; Influenza A Virus, H5N8 Subtype; Animals, Wild; Prevalence; Birds; Influenza, Human; Phylogeny; Disease Outbreaks
PubMed: 36682670
DOI: 10.1016/j.micpath.2023.106001 -
PloS One 2016Avian influenza viruses are able to persist in the environment, in-between the transmission of the virus among its natural hosts. Quantifying the environmental factors... (Meta-Analysis)
Meta-Analysis Review
Avian influenza viruses are able to persist in the environment, in-between the transmission of the virus among its natural hosts. Quantifying the environmental factors that affect the persistence of avian influenza virus is important for influencing our ability to predict future outbreaks and target surveillance and control methods. We conducted a systematic review and quantitative meta-analysis of the environmental factors that affect the decay of low pathogenic avian influenza virus (LPAIV) in water. Abiotic factors affecting the persistence of LPAIV have been investigated for nearly 40 years, yet published data was produced by only 26 quantitative studies. These studies have been conducted by a small number of principal authors (n = 17) and have investigated a narrow range of environmental conditions, all of which were based in laboratories with limited reflection of natural conditions. The use of quantitative meta-analytic techniques provided the opportunity to assess persistence across a greater range of conditions than each individual study can achieve, through the estimation of mean effect-sizes and relationships among multiple variables. Temperature was the most influential variable, for both the strength and magnitude of the effect-size. Moderator variables explained a large proportion of the heterogeneity among effect-sizes. Salinity and pH were important factors, although future work is required to broaden the range of abiotic factors examined, as well as including further diurnal variation and greater environmental realism generally. We were unable to extract a quantitative effect-size estimate for approximately half (50.4%) of the reported experimental outcomes and we strongly recommend a minimum set of quantitative reporting to be included in all studies, which will allow robust assimilation and analysis of future findings. In addition we suggest possible means of increasing the applicability of future studies to the natural environment, and evaluating the biological content of natural waterbodies.
Topics: Animals; Birds; Disease Outbreaks; Influenza A virus; Influenza in Birds; Salinity; Temperature; Water Microbiology
PubMed: 27736884
DOI: 10.1371/journal.pone.0161929 -
Clinical Microbiology and Infection :... Oct 2015Administration of corticosteroids to patients affected by influenza virus, especially pandemic avian influenza virus, although relatively common, remains controversial.... (Meta-Analysis)
Meta-Analysis Review
Administration of corticosteroids to patients affected by influenza virus, especially pandemic avian influenza virus, although relatively common, remains controversial. A systematic review and meta-analysis was performed to assess the impact of corticosteroid treatment on outcomes of patients with influenza virus infection. The PubMed, EMBASE, Web of Science and Cochrane Library databases were searched up to February, 2015. Studies comparing corticosteroid treatment with no corticosteroid treatment in patients with influenza virus infection were included. The primary outcomes assessed were the association of mortality and nosocomial infection with corticosteroid treatment. Two authors independently extracted the data. ORs and weighted mean differences (WMDs) were used to describe dichotomous data and continuous data, respectively. Nineteen studies with 4916 patients were included in this meta-analysis. The results showed that corticosteroid treatment was significantly associated with mortality (OR 1.98, 95% CI 1.62-2.43, p < 0.00001) and nosocomial infection (OR 3.16, 95% CI 2.09-4.78, p < 0.00001). The durations of mechanical ventilation (WMD 3.82, 95% CI 1.49-6.15, p 0.001) and intensive-care unit stay (WMD 4.78, 95% CI 2.27-7.29, p 0.0002) were both markedly longer in the corticosteroid treatment group than in the control group. These findings suggest that routine steroid use may not be ideal for influenza virus infection. However, these results are derived from observational studies, with some important biases. They should be examined in future sufficiently powered randomized trials.
Topics: Adrenal Cortex Hormones; Anti-Inflammatory Agents; Cross Infection; Humans; Influenza, Human; Length of Stay; Respiration, Artificial; Survival Analysis; Treatment Outcome
PubMed: 26123860
DOI: 10.1016/j.cmi.2015.06.022