-
Le Infezioni in Medicina Jun 2019The Nipah virus was discovered twenty years ago, and there is considerable information available regarding the specificities surrounding this virus such as transmission,...
The Nipah virus was discovered twenty years ago, and there is considerable information available regarding the specificities surrounding this virus such as transmission, pathogenesis and genome. Belonging to the Henipavirus genus, this virus can cause fever, encephalitis and respiratory disorders. The first cases were reported in Malaysia and Singapore in 1998, when affected individuals presented with severe febrile encephalitis. Since then, much has been identified about this virus. These single-stranded RNA viruses gain entry into target cells via a process known as macropinocytosis. The viral genome is released into the cell cytoplasm via a cascade of processes that involves conformational changes in G and F proteins which allow for attachment of the viral membrane to the cell membrane. In addition to this, the natural reservoirs of this virus have been identified to be fruit bats from the genus Pteropus. Five of the 14 species of bats in Malaysia have been identified as carriers, and this virus affects horses, cats, dogs, pigs and humans. Various mechanisms of transmission have been proposed such as contamination of date palm saps by bat feces and saliva, nosocomial and human-to-human transmissions. Physical contact was identified as the strongest risk factor for developing an infection in the 2004 Faridpur outbreak. Geographically, the virus seems to favor the Indian sub-continent, Indonesia, Southeast Asia, Pakistan, southern China, northern Australia and the Philippines, as demonstrated by the multiple outbreaks in 2001, 2004, 2007, 2012 in Bangladesh, India and Pakistan as well as the initial outbreaks in Malaysia and Singapore. Multiple routes of the viremic spread in the human body have been identified such as the central nervous system (CNS) and respiratory system, while virus levels in the body remain low, detection in the cerebrospinal fluid is comparatively high. The virus follows an incubation period of 4 days to 2 weeks which is followed by the development of symptoms. The primary clinical signs include fever, headache, vomiting and dizziness, while the characteristic symptoms consist of segmental myoclonus, tachycardia, areflexia, hypotonia, abnormal pupillary reflexes and hypertension. The serum neutralization test (SNT) is the gold standard of diagnosis followed by ELISA if SNT cannot be carried out. On the other hand, treatment is supportive since there a lack of effective pharmacological therapy and only one equine vaccine is currently licensed for use. Prevention of outbreaks seems to be a more viable approach until specific therapeutic strategies are devised.
Topics: Animals; Asia; Cats; Chiroptera; Communicable Diseases, Emerging; Disease Reservoirs; Dogs; Epidemics; Henipavirus Infections; Horses; Humans; Nipah Virus; Pinocytosis; Swine; Symptom Assessment; Vaccination; Virus Internalization
PubMed: 31205033
DOI: No ID Found -
PloS One 2019Canine morbillivirus (canine distemper virus, CDV) persists as a serious threat to the health of domestic dogs and wildlife. Although studies have been conducted on the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Canine morbillivirus (canine distemper virus, CDV) persists as a serious threat to the health of domestic dogs and wildlife. Although studies have been conducted on the frequency and risk factors associated with CDV infection, there are no comprehensive data on the current epidemiological magnitude in the domestic dog population at regional and national levels. Therefore, we conducted a cross-sectional study and included our results in a meta-analysis to summarize and combine available data on the frequency and potential risk factors associated with CDV infection.
METHODS
For the cross-sectional study, biological samples from dogs suspected to have canine distemper (CD) were collected and screened for viral RNA. Briefly, the PRISMA protocol was used for the meta-analysis, and data analyses were performed using STATA IC 13.1 software.
RESULTS
CDV RNA was detected in 34% (48/141) of dogs suspected to have CD. Following our meta-analysis, 53 studies were selected for a total of 11,527 dogs. Overall, the pooled frequency of CDV positivity based on molecular and serological results were 33% (95% CI: 23-43) and 46% (95% CI: 36-57), respectively. The pooled subgroup analyses of clinical signs, types of biological samples, diagnostic methods and dog lifestyle had a wide range of CDV positivity (range 8-75%). Free-ranging dogs (OR: 1.44, 95% CI: 1.05-1.97), dogs >24 months old (OR: 1.83, 95% CI: 1.1-3) and unvaccinated dogs (OR: 2.92, 95% CI: 1.26-6.77) were found to be positively associated with CDV infection. In contrast, dogs <12 months old (OR: 0.36, 95% CI: 0.20-0.64) and dogs with a complete anti-CDV vaccination (OR: 0.18, 95% CI: 0.05-0.59) had a negative association.
CONCLUSION
Considering the high frequency of CDV positivity associated with almost all the variables analyzed in dogs, it is necessary to immediately and continuously plan mitigation strategies to reduce the CDV prevalence, especially in determined endemic localities.
Topics: Animals; Cross-Sectional Studies; Distemper; Distemper Virus, Canine; Dogs; Prevalence; RNA, Viral
PubMed: 31141576
DOI: 10.1371/journal.pone.0217594 -
Human Vaccines & Immunotherapeutics Dec 2022This study comprehensively evaluated and compared three human rabies vaccines. Seven electronic databases were systematically searched. The Cochrane Handbook v5.1.0 was... (Meta-Analysis)
Meta-Analysis
Immunogenicity and safety of human diploid cell vaccine (HDCV) vs. purified Vero cell vaccine (PVRV) vs. purified chick embryo cell vaccine (PCECV) used in post-exposure prophylaxis: a systematic review and meta-analysis.
This study comprehensively evaluated and compared three human rabies vaccines. Seven electronic databases were systematically searched. The Cochrane Handbook v5.1.0 was used to assess the risk of bias. A random-effects model was used to combine individual rates, and network meta-analysis was used for pairwise comparisons. Twenty-seven articles were included, with a total of 18,630 participants. The pooled incidence of the total adverse reaction to HDCV was significantly lower than that of PCECV. HDCV administration resulted in a lower incidence of local pain, fever, and weakness than purified Vero cell vaccine. HDCV caused a lower incidence of local pain and fever than PCECV. No significant difference was observed in terms of the seroconversion rate on day 7 or the rabies virus-neutralizing antibody titer on day 14. HDCV demonstrated superiority in terms of safety compared with the other two rabies vaccines, while the same was not observed in terms of immunogenicity.
Topics: Animals; Antibodies, Viral; Chick Embryo; Chickens; Chlorocebus aethiops; Diploidy; Fever; Humans; Pain; Post-Exposure Prophylaxis; Rabies; Rabies Vaccines; Rabies virus; Vero Cells
PubMed: 35192787
DOI: 10.1080/21645515.2022.2027714 -
Journal of Global Health Dec 2017Acute lower respiratory tract infections (ALRIs) caused by respiratory syncytial virus (RSV) are a leading cause of hospitalization in infants. Numerous risk factors... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Acute lower respiratory tract infections (ALRIs) caused by respiratory syncytial virus (RSV) are a leading cause of hospitalization in infants. Numerous risk factors have been identified in the aetiology of severe RSV-associated ALRI necessitating hospitalisation, including prematurity and congenital heart disease. Down syndrome (DS), a common genetic disorder associated with congenital and dysmorphic features, has recently been identified as an independent risk factor for RSV-associated ALRI requiring hospitalisation; however, the disease burden of RSV-associated ALRI in this population has not yet been established. Similarly, the impact of DS as an independent risk factor has not yet been quantified. We aimed therefore to estimate the incidence of admissions in children with DS, and by comparing this with unaffected children, to quantify the risk of DS independent of other risk factors.
METHODS
A systematic review of the existing literature published between 1995 and March 1, 2017 was performed to quantify the incidence of hospitalisation due to RSV-associated ALRI in children with DS. Meta-analyses were performed on extracted data using STATA statistical software, and hospitalisation rates for children with and without DS under the age of 2 were calculated.
FINDINGS
5 articles were ultimately deemed eligible for analyses. Analyses were limited to children under the age of 2 years. We calculated the hospitalisation rate for children with DS in this age group to be 117.6 per 1000 child-years (95% CI 67.4-205.2), vs a rate of 15.2 per 1000 child-years (95% CI 8.3-27.6) in unaffected children. This indicates DS contributes to a 6.8 (95% CI 5.5-8.4) fold increase in the relative risk of hospitalisation for RSV-associated ALRI.
INTERPRETATION
Though limited by a small number of articles, this review found sufficient evidence to conclude DS was a significant independent risk factor for the development of severe RSV-associated ALRI requiring hospitalisation. Further studies are needed to define the impact of DS in conjunction with other comorbidities on the risk of severe RSV infection. Determining benefits of immunoprophylaxis or future vaccines against RSV in this at-risk population is warranted.
Topics: Acute Disease; Child; Down Syndrome; Hospitalization; Humans; Incidence; Respiratory Syncytial Viruses; Respiratory Tract Infections; Risk Factors
PubMed: 29302319
DOI: 10.7189/jogh.07.020413 -
The Journal of Infectious Diseases Mar 2022Although global reviews of infant respiratory syncytial virus (RSV) burden exist, none have summarized data from the United States or evaluated how RSV burden estimates... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Although global reviews of infant respiratory syncytial virus (RSV) burden exist, none have summarized data from the United States or evaluated how RSV burden estimates are influenced by variations in study design.
METHODS
We performed a systematic literature review and meta-analysis of studies describing RSV-associated hospitalization rates among US infants and examined the impact of key study characteristics on these estimates.
RESULTS
We reviewed 3328 articles through 14 August 2020 and identified 25 studies with 31 unique estimates of RSV-associated hospitalization rates. Among US infants <1 year of age, annual rates ranged from 8.4 to 40.8 per 1000 with a pooled rate of 19.4 (95% confidence interval [CI], 17.9-20.9). Study type influenced RSV-associated hospitalization rates (P = .003), with active surveillance studies having pooled rates (11.0; 95% CI, 9.8-12.2) that were half that of studies based on administrative claims (21.4; 19.5-23.3) or modeling approaches (23.2; 20.2-26.2).
CONCLUSIONS
Applying our pooled rates to the 2020 US birth cohort suggests that 79 850 (95% CI, 73 680-86 020) RSV-associated infant hospitalizations occur each year. The full range of RSV-associated hospitalization rates identified in our review can better inform future evaluations of RSV prevention strategies. More research is needed to better understand differences in estimated RSV burden across study design.
Topics: Hospitalization; Humans; Infant; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Human; United States
PubMed: 33346360
DOI: 10.1093/infdis/jiaa752 -
Journal of Clinical Virology : the... Aug 2020Respiratory syncytial virus (RSV) immunoprophylaxis (IP) has been shown to reduce RSV hospitalization rates in high-risk infants; however, it is unclear whether RSV IP...
Respiratory syncytial virus (RSV) immunoprophylaxis (IP) has been shown to reduce RSV hospitalization rates in high-risk infants; however, it is unclear whether RSV IP is associated with increased risk of non-RSV disease, particularly non-RSV hospitalizations. We conducted a systematic literature review to understand the occurrences of non-RSV disease and/or non-RSV hospitalizations in published studies of RSV IP. Cochrane, Embase, and PubMed databases were searched and reviewed to summarize data regarding the incidence of RSV and non-RSV respiratory disease among RSV IP recipients and controls in randomized and non-randomized studies. Independent investigators screened and selected studies for inclusion. Risk-of-bias assessment was conducted to assess strength/validity of the data using the Jadad scoring system and Downs and Black quality assessment tool, where appropriate. Twenty studies were included for review (5 randomized controlled trials [RCTs]; 15 non-randomized studies). RCTs of RSV IP demonstrated reductions in RSV hospitalizations and all-cause hospitalizations, with no increase in hospitalizations for non-RSV disease. Non-randomized studies also demonstrated reduced RSV hospitalizations in RSV IP recipients but had mixed results in assessments of hospitalizations for non-RSV disease. When RSV IP recipients and controls were more similar in disease severity risk, results of non-randomized studies aligned more closely with RCTs. Observations of increased non-RSV hospitalization rates among RSV IP recipients in some non-randomized studies could be primarily explained by differences in the clinical characteristics between RSV IP recipients and controls.
Topics: Databases, Factual; Hospitalization; Humans; Incidence; Infant; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Human
PubMed: 32512375
DOI: 10.1016/j.jcv.2020.104339 -
BMC Medicine Jun 2020Major infectious disease outbreaks are a constant threat to human health. Clinical research responses to outbreaks generate evidence to improve outcomes and outbreak...
BACKGROUND
Major infectious disease outbreaks are a constant threat to human health. Clinical research responses to outbreaks generate evidence to improve outcomes and outbreak control. Experiences from previous epidemics have identified multiple challenges to undertaking timely clinical research responses. This scoping review is a systematic appraisal of political, economic, administrative, regulatory, logistical, ethical and social (PEARLES) challenges to clinical research responses to emergency epidemics and solutions identified to address these.
METHODS
A scoping review. We searched six databases (MEDLINE, Embase, Global Health, PsycINFO, Scopus and Epistemonikos) for articles published from 2008 to July 2018. We included publications reporting PEARLES challenges to clinical research responses to emerging epidemics and pandemics and solutions identified to address these. Two reviewers screened articles for inclusion, extracted and analysed the data.
RESULTS
Of 2678 articles screened, 76 were included. Most presented data relating to the 2014-2016 Ebola virus outbreak or the H1N1 outbreak in 2009. The articles related to clinical research responses in Africa (n = 37), Europe (n = 8), North America (n = 5), Latin America and the Caribbean (n = 3) and Asia (n = 1) and/or globally (n = 22). A wide range of solutions to PEARLES challenges was presented, including a need to strengthen global collaborations and coordination at all levels and develop pre-approved protocols and equitable frameworks, protocols and standards for emergencies. Clinical trial networks and expedited funding and approvals were some solutions implemented. National ownership and community engagement from the outset were a key enabler for delivery. Despite the wide range of recommended solutions, none had been formally evaluated.
CONCLUSIONS
To strengthen global preparedness and response to the COVID-19 pandemic and future epidemics, identified solutions for rapid clinical research deployment, delivery, and dissemination must be implemented. Improvements are urgently needed to strengthen collaborations, funding mechanisms, global and national research capacity and capability, targeting regions vulnerable to epidemics and pandemics. Solutions need to be flexible to allow timely adaptations to context, and research led by governments of affected regions. Research communities globally need to evaluate their activities and incorporate lessons learnt to refine and rehearse collaborative outbreak response plans in between epidemics.
Topics: Betacoronavirus; Biomedical Research; COVID-19; Coronavirus Infections; Delivery of Health Care; Disease Outbreaks; Ebolavirus; Epidemics; Global Health; Health Services Needs and Demand; Humans; Influenza A Virus, H1N1 Subtype; Pandemics; Pneumonia, Viral; SARS-CoV-2
PubMed: 32586391
DOI: 10.1186/s12916-020-01624-8 -
Travel Medicine and Infectious Disease 2024Ebola virus disease (Ebola) is highly pathogenic, transmissible, and often deadly, with debilitating consequences. Superspreading within a cluster is also possible. In... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Ebola virus disease (Ebola) is highly pathogenic, transmissible, and often deadly, with debilitating consequences. Superspreading within a cluster is also possible. In this study, we aim to document Ebola basic reproduction number (R): the average number of new cases associated with an Ebola case in a completely susceptible population.
METHODS
We undertook a systematic review and meta-analysis. We searched PubMed, EMBASE, and Web of Science for studies published between 1976 and February 27, 2023. We also manually searched the reference lists of the reviewed studies to identify additional studies. We included studies that reported R during Ebola outbreaks in Africa. We excluded studies that reported only the effective reproduction number (R). Abstracting data from included studies was performed using a pilot-tested standard form. Two investigators reviewed the studies, extracted the data, and assessed quality. The pooled R was determined by a random-effects meta-analysis. R was stratified by country. We also estimated the theoretically required immunization coverage to reach herd-immunity using the formula of (1-1/R) × 100 %.
RESULTS
The search yielded 2042 studies. We included 53 studies from six African countries in the systematic review providing 97 Ebola mean R estimates. 27 (with 46 data points) studies were included in the meta-analysis. The overall pooled mean Ebola R was 1.95 (95 % CI 1.74-2.15), with high heterogeneity (I = 99.99 %; τ = 0.38; and p < 0.001) and evidence of small-study effects (Egger's statistics: Z = 4.67; p < 0.001). Mean Ebola R values ranged from 1.2 to 10.0 in Nigeria, 1.1 to 7 in Guinea, 1.14 to 8.33 in Sierra Leone, 1.13 to 5 in Liberia, 1.2 to 5.2 in DR Congo, 1.34 to 2.7 in Uganda, and from 1.40 to 2.55 for all West African countries combined. Pooled mean Ebola R was 9.38 (95 % CI 4.16-14.59) in Nigeria, 3.31 (95 % CI 2.30-4.32) in DR Congo, 2.0 (95 % CI 1.25-2.76) in Uganda, 1.83 (95 % CI 1.61-2.05) in Liberia, 1.73 (95 % CI 1.47-2.0) in Sierra Leonne, and 1.44 (95 % CI 1.29-1.60) in Guinea. In theory, 50 % of the population needs to be vaccinated to achieve herd immunity, assuming that Ebola vaccine would be 100 % effective.
CONCLUSIONS
Ebola R varies widely across countries. Ebola has a much wider R range than is often claimed (1.3-2.0). It is possible for an Ebola index case to infect more than two susceptible individuals.
Topics: Humans; Hemorrhagic Fever, Ebola; Ebolavirus; Basic Reproduction Number; Ebola Vaccines; Disease Outbreaks; Liberia; Nigeria
PubMed: 38181864
DOI: 10.1016/j.tmaid.2023.102685 -
Epidemics Jun 2021Due to high burden of respiratory syncytial virus (RSV) in low- and middle-income countries (LMIC), international funding organizations have prioritized the development...
BACKGROUND
Due to high burden of respiratory syncytial virus (RSV) in low- and middle-income countries (LMIC), international funding organizations have prioritized the development of RSV vaccines. Mathematical models of RSV will play an important role in assessing the relative value of these interventions. Our objectives were to provide an overview of the existing RSV modelling literature in LMIC and summarize available results on population-level effectiveness and cost-effectiveness.
METHODS
We searched MEDLINE from 2000 to 2020 for English language publications that employed a mathematical model of RSV calibrated to LMIC. Qualitative data were extracted on study and model characteristics. Quantitative data were collected on key model input assumptions and base case effectiveness and cost-effectiveness estimates for various immunization strategies.
FINDINGS
Of the 283 articles reviewed, 15 met inclusion criteria. Ten studies used modelling techniques to explore RSV transmission and/or natural history, while eight studies evaluated RSV vaccines and/or monoclonal antibodies, three of which included cost-effectiveness analyses. Six studies employed deterministic compartmental models, five studies employed individual transmission models, and four studies used different types of cohort models. Nearly every model was calibrated to at least one middle-income country, while four were calibrated to low-income countries.
INTERPRETATION
The mathematical modelling literature in LMIC has demonstrated the potential effectiveness of RSV vaccines and monoclonal antibodies. This review has demonstrated the importance of accounting for seasonality, social contact rates, immunity from prior infection and maternal antibody transfer. Future models should consider incorporating individual-level risk factors, subtype-specific effects, long-term sequelae of RSV infections, and out-of-hospital mortality.
Topics: Developing Countries; Humans; Models, Theoretical; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus Vaccines; Respiratory Syncytial Virus, Human
PubMed: 33662812
DOI: 10.1016/j.epidem.2021.100444 -
PloS One 2021Viral outbreaks present a particular challenge in countries in Africa where there is already a high incidence of other infectious diseases, including malaria which can... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Viral outbreaks present a particular challenge in countries in Africa where there is already a high incidence of other infectious diseases, including malaria which can alter immune responses to secondary infection. Ebola virus disease (EVD) is one such problem; understanding how Plasmodium spp. and Ebolavirus (EBOV) interact is important for future outbreaks.
METHODS
We conducted a systematic review in PubMed and Web of Science to find peer-reviewed papers with primary data literature to determine 1) prevalence of EBOV/Plasmodium spp. coinfection, 2) effect of EBOV/Plasmodium spp. coinfection on EVD pathology and the immune response, 3) impact of EBOV/Plasmodium spp. coinfection on the outcome of EVD-related mortality. Random effects meta-analyses were conducted with the R package meta to produce overall proportion and effect estimates as well as measure between-study heterogeneity.
RESULTS
From 322 peer-reviewed papers, 17 were included in the qualitative review and nine were included in a meta-analysis. Prevalence of coinfection was between 19% and 72%. One study reported significantly lower coagulatory response biomarkers in coinfected cases but no difference in inflammatory markers. Case fatality rates were similar between EBOV(+)/Pl(+) and EBOV(+)/Pl(-) cases (62.8%, 95% CI 49.3-74.6 and 56.7%, 95% CI 53.2-60.1, respectively), and there was no significant difference in risk of mortality (RR 1.09, 95% CI 0.90-1.31) although heterogeneity between studies was high. One in vivo mouse model laboratory study found no difference in mortality by infection status, but another found prior acute Plasmodium yoeli infection was protective against morbidity and mortality via the IFN-γ signalling pathway.
CONCLUSION
The literature was inconclusive; studies varied widely and there was little attempt to adjust for confounding variables. Laboratory studies may present the best option to answer how pathogens interact within the body but improvement in data collection and analysis and in diagnostic methods would aid patient studies in the future.
Topics: Animals; Coinfection; Disease Outbreaks; Ebolavirus; Hemorrhagic Fever, Ebola; Humans; Malaria; Prevalence
PubMed: 34029352
DOI: 10.1371/journal.pone.0251101