-
New Microbes and New Infections 2024Avian influenza A H5N1 is a significant global public health threat. Although relevant, systematic reviews about its prevalence in animals are lacking. (Review)
Review
INTRODUCTION
Avian influenza A H5N1 is a significant global public health threat. Although relevant, systematic reviews about its prevalence in animals are lacking.
METHODS
We performed a systematic literature review in bibliographic databases to assess the prevalence of H5N1 in animals. A meta-analysis with a random-effects model was performed to calculate the pooled prevalence and 95 % confidence intervals (95%CI). In addition, measures of heterogeneity (Cochran's Q statistic and I test) were reported.
RESULTS
The literature search yielded 1359 articles, of which 33 studies were fully valid for analysis, including 96,909 animals. The pooled prevalence for H5N1 in birds (n = 90,045, 24 studies) was 5.0 % (95%CI: 4.0-6.0 %; I = 99.21); in pigs (n = 3,178, 4 studies) was 1.0 % (95%CI: 0.0-1.0 %); in cats (n = 2,911, 4 studies) was 0.0 % (95%CI: 0.0-1.0 %); and in dogs (n = 479, 3 studies) was 0.0 % (95%CI: 0.0-2.0 %).
CONCLUSIONS
While the occurrence of H5N1 in animals might be comparatively limited compared to other influenza viruses, its impact on public health can be substantial when it transmits to humans. This virus can potentially induce severe illness and has been linked to previous outbreaks. Therefore, it is essential to closely monitor and comprehend the factors influencing the prevalence of H5N1 in both avian and human populations to develop effective disease control and prevention strategies.
PubMed: 38911488
DOI: 10.1016/j.nmni.2024.101439 -
One Health (Amsterdam, Netherlands) Jun 2024The global spread of highly pathogenic avian influenza (HPAI) A (H5N1) clade 2.3.4.4b virus since 2021 necessitates a re-evaluation of the role of vaccination in...
The global spread of highly pathogenic avian influenza (HPAI) A (H5N1) clade 2.3.4.4b virus since 2021 necessitates a re-evaluation of the role of vaccination in controlling HPAI outbreaks among poultry, which has been controversial because of the concern of silent spread with viral mutation and spillover to human. We systematically reviewed and meta-analyzed all existing data from experimental challenge trials to assess the efficacy of HPAI vaccines against mortality in specific pathogen free (SPF) chickens, with evaluation of the certainty of evidence (CoE) using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Out of 223 screened publications, 46 trials met our eligibility criteria. Inactivated vaccines showed an efficacy of 95% (risk ratio [RR] = 5% [95% CI: 1% to 17%], = 0%, CoE high) against homologous strains and an efficacy of 78% (RR = 22% [95% CI: 14% to 37%], = 18%, CoE high) against heterologous strains (test for subgroup difference = 0.02). Live recombinant vaccines exhibited the highest efficacy at 97% (RR = 3% [95% CI: 1% to 13%], = 0%, CoE high). Inactivated recombinant vaccines had an overall efficacy of 90% (RR = 10% [95% CI: 6% to 16%], = 47%, CoE high). Commercial vaccines showed an overall efficacy of 91% (RR = 9% [95% CI: 5% to 17%], = 23%, CoE high), with 96% efficacy (RR = 4% [95% CI: 1% to 21%], = 0%, CoE high) against homologous strains and 90% efficacy (RR = 10% [95% CI: 5% to 20%], = 31%, CoE moderate) against heterologous strains. Our systematic review offers an updated and unbiased assessment of vaccine efficacy against HPAI-related mortality, providing timely and crucial information for re-evaluating the role of vaccination in poultry avian influenza control policy amist the global HPAI outbreak post-2021.
PubMed: 38596323
DOI: 10.1016/j.onehlt.2024.100714 -
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 -
Veterinary Research Oct 2023The global spread of avian influenza A viruses in domestic birds is causing increasing socioeconomic devastation. Various mechanistic models have been developed to... (Review)
Review
The global spread of avian influenza A viruses in domestic birds is causing increasing socioeconomic devastation. Various mechanistic models have been developed to better understand avian influenza transmission and evaluate the effectiveness of control measures in mitigating the socioeconomic losses caused by these viruses. However, the results of models of avian influenza transmission and control have not yet been subject to a comprehensive review. Such a review could help inform policy makers and guide future modeling work. To help fill this gap, we conducted a systematic review of the mechanistic models that have been applied to field outbreaks. Our three objectives were to: (1) describe the type of models and their epidemiological context, (2) list estimates of commonly used parameters of low pathogenicity and highly pathogenic avian influenza transmission, and (3) review the characteristics of avian influenza transmission and the efficacy of control strategies according to the mechanistic models. We reviewed a total of 46 articles. Of these, 26 articles estimated parameters by fitting the model to data, one evaluated the effectiveness of control strategies, and 19 did both. Values of the between-individual reproduction number ranged widely: from 2.18 to 86 for highly pathogenic avian influenza viruses, and from 4.7 to 45.9 for low pathogenicity avian influenza viruses, depending on epidemiological settings, virus subtypes and host species. Other parameters, such as the durations of the latent and infectious periods, were often taken from the literature, limiting the models' potential insights. Concerning control strategies, many models evaluated culling (n = 15), while vaccination received less attention (n = 6). According to the articles reviewed, optimal control strategies varied between virus subtypes and local conditions, and depended on the overall objective of the intervention. For instance, vaccination was optimal when the objective was to limit the overall number of culled flocks. In contrast, pre-emptive culling was preferred for reducing the size and duration of an epidemic. Early implementation consistently improved the overall efficacy of interventions, highlighting the need for effective surveillance and epidemic preparedness.
Topics: Animals; Influenza in Birds; Poultry; Disease Outbreaks; Influenza A virus; Animals, Domestic
PubMed: 37853425
DOI: 10.1186/s13567-023-01219-0 -
Vaccine Aug 2023Vaccines for avian influenza (AI) can protect poultry against disease, mortality, and virus transmission. Numerous factors, including: vaccine platform, immunogenicity,... (Meta-Analysis)
Meta-Analysis Review
Vaccines for avian influenza (AI) can protect poultry against disease, mortality, and virus transmission. Numerous factors, including: vaccine platform, immunogenicity, and relatedness to the field strain, are known to be important to achieving optimal AI vaccine efficacy. To better understand how these factors contribute to vaccine protection, a systematic meta-analysis was conducted to evaluate efficacy data for vaccines in chickens challenged with highly pathogenic (HP) AI. Data from a total of 120 individual trials from 25 publications were selected and evaluated. Two vaccine criteria were evaluated for their effects on two metrics of protection. The vaccine criteria were: 1) the relatedness of the vaccine antigen and challenge strain in the hemagglutinin 1 domain (HA1) protein sequence; 2) vaccine-induced antibody titers to the challenge virus (VIAC). The metrics of protection were: A) survival of vaccinated chickens vs unvaccinated controls; and B) reduction in oral virus-shedding by vaccinated vs unvaccinated controls 2-4 days post challenge. Three vaccine platforms were evaluated: oil-adjuvanted inactivated whole AI virus, recombinant herpes virus of turkeys (rHVT) vectored, and a non-replicating alpha-virus vectored RNA particle (RP) vaccine. Higher VIAC correlated with greater reduction of virus-shed and vaccine efficacy by all vaccine platforms. Both higher HA1 relatedness and higher VIAC using challenge virus as antigen correlated with better survival by inactivated vaccines and rHVT-vectored vaccines. However, rHVT-vectored and RP based vaccines were more tolerant of variation in the HA1; the relatedness of the HA1 of the vaccine and challenge virus did not significantly correlate with survival with rHVT-vectored vaccines. Protection was achieved with the lowest aa similarity for which there was data, 90-93 % for rHVT vaccines and 88 % for the RP vaccine.
Topics: Animals; Chickens; Influenza Vaccines; Influenza in Birds; Influenza A Virus, H5N1 Subtype; Vaccines, Synthetic; Influenza A virus; Herpesvirus 1, Meleagrid
PubMed: 37537093
DOI: 10.1016/j.vaccine.2023.07.076