Health promotion and person-to-person disease outbreaks
Glenn Laverack in Health Promotion in Disease Outbreaks and Health Emergencies, 2017
Most human cases of avian influenza are transmitted through contact with infected poultry or contaminated environments such as live poultry markets and farms. Slaughtering and preparing poultry for consumption, including in household settings, are also risk factors for disease transmission. Infected birds transmit the virus in their saliva, mucous and faeces. People who work directly with poultry during an outbreak are at a high risk of transmission and should be the target for health promotion interventions. Person-to-person infections normally happen when the virus gets into the eyes, nose or mouth, or is inhaled in droplets or dust. Health promotion also has a role to target the general population to raise awareness about prevention practices such as hand-washing and about the early signs and symptoms of the disease. Health promotion can improve personal skills for infection control practices such as disinfection and can raise awareness about the effectiveness and availability of antiviral drugs. Everyone must be reminded of their responsibility to report suspected cases to the health authorities and can be facilitated through information about websites and emergency telephone numbers. Health promotion uses communication approaches to raise awareness, including the mass media, print materials and peer- or face-to-face education.
Environmental Variables in the Transmission of Respiratory Viruses
Sunit K. Singh in Human Respiratory Viral Infections, 2014
The 2003 outbreak of highly pathogenic avian influenza (HPAI) H7N7 viruses among poultry flocks in the Netherlands was a geographically defined epizootic, caused by a virus not usually endemic to the region, during which strict controls on the movement of the involved species were in place. Although avian influenza viruses are classically thought to be gastrointestinal pathogens, primarily transmitted among birds by a fecal–oral route, respiratory transmission of an HPAI H5N1 virus between chickens separately caged up to 1.1 m apart has been documented in a controlled laboratory setting.83,84 The spread of H7N7 among noncontiguous Dutch poultry farms, without known epidemiological links, is a case study for the transmission of influenza viruses over relatively large time and distance scales.
Influenza neurologic complications
Avindra Nath, Joseph R. Berger in Clinical Neurovirology, 2020
Due to the distribution of influenza receptors in the respiratory tract, human influenza viruses primarily infect the upper respiratory tract while there is an absence of avian influenza receptors in the upper airway. H5N1 strains bind to receptors found on type II pneumocytes, bronchi, bronchioli, trachea, few cells in the upper respiratory tract, Kupfer cells, glomerular cells, splenic T cells, and neurons in the brain and intestine [162]. Should avian influenza strains mutate to easily bind to receptors found in the upper respiratory tract, it could become transmissible and possibly lead to a pandemic. Furthermore, the studies of Herfst et al. [163] and Imai et al. [164] showed that HPAI viruses can acquire the necessary mutations to become aerosol transmissible following multiple passages through a mammalian host. However, this resulted in a virus capable of causing lung lesions and weight loss, but was not highly pathogenic or cause lethality.
Assessment of serum ferritin as a biomarker in COVID-19: bystander or participant? Insights by comparison with other infectious and non-infectious diseases
Published in Biomarkers, 2020
Kai Kappert, Amir Jahić, Rudolf Tauber
Avian influenza is a variant of influenza A caused by the H5N1 virus adapted to birds. Although primarily known to birds, it can also adapt stably and maintain transmission within humans. 455 people died of H5N1 worldwide since 2003 by 2019 (Uyeki and Peiris 2019), in particular in Central Asia, South Asia, the Middle East, and parts of Africa. Laboratory findings of patients suffering from H5N1 commonly included low lymphocyte counts and moderately decreased platelet counts at admission. During hospitalisation, elevated concentrations of lactate, creatinine kinase, liver enzymes as well as lower albumin concentrations were frequently detected. However, only lower counts of neutrophilic leukocytes and elevated alanine aminotransferase were associated with higher mortality rates in H5N1 disease (Uyeki and Peiris 2019). Thus, the laboratory changes of blood biomarkers reported in H5N1 patients seem rather unspecific. Only a few publications described ferritin changes during the H5N1 disease course. A scientific report summarised the clinical and laboratory findings of 22 patients infected with H5N1. Among them, in eight patients measurement of serum ferritin was performed with six patients displaying concentrations above the reference range (Soepandi et al.2010).
Chicken toll-like receptors and their significance in immune response and disease resistance
Published in International Reviews of Immunology, 2019
Aamir Nawab, Lilong An, Jiang Wu, Guanghui Li, Wenchao Liu, Yi Zhao, Qimin Wu, Mei Xiao
Avian influenza (AI) is a disease caused by the influenza virus which affects all species of poultry birds. AI also causes a threat to human life due to its zoonotic nature [99]. TLR7 is one of the various types of TLRs in birds that only binds with viral ssRNA (single-stranded ribonucleic acid) or its synthetic analogs such as imiquimod, loxoribine, resiquimod, and gardiquimod [48, 72, 118, 143]. In chickens, ssRNA can induce antiviral effects against infectious bursal disease (IBD) [116, 119]. Avian Influenza viruses can effectively inhibit the birds’ ability to produce interferons which, in turn, suppress the antiviral defense mechanisms. Avian macrophages produce IL-1β via stimulation with ssRNA [121]. Various published papers have revealed that the stimulation of avian macrophages with chTLR21 ligand (CpG DNA) up-regulated IL-1β mRNA expression [121]. The up-regulation of IL-1β was due to ssRNA treatment which attributes its antiviral response against H4N6 LPAIV (low pathogenic avian influenza virus) infection [123]. The author has described that IL-1β inhibits the replication of West Nile virus [124] and produces resistance in the birds against the avian influenza viral infection [123, 155].
Emerging antiviral therapies and drugs for the treatment of influenza
Published in Expert Opinion on Emerging Drugs, 2022
Jinshen Wang, Yihang Sun, Shuwen Liu
The intra-racial and inter-species transmission of human and avian influenza represents a major public health concern and can significantly burden our economy. The latest 2009 Mexican or swine flu pandemic was caused by the H1N1 subtype influenza virus, which affected 214 countries, costing about 200,000 lives [199]. In this case, vaccines are still the most effective means of preventing infection, which can largely avoid large-scale pandemics and reduce other losses. Current vaccines are designed to elicit neutralizing antibodies against the influenza HA protein and, to a lesser degree, against neuraminidase. This approach accounts for the efficacy of most vaccines against only a few subtypes of IAV or influenza B virus infection. In contrast, both recombinant protein vaccines and virosomes vaccines, such as Peptide-HA, NP, M1(BiondVax) and Alphasvirus-HA(Alphavax), demonstrate a wider scope of prevention and enable more targeted delivery of conserved antigens, which can stimulate the innate and adaptive immune systems [200]. Developing universal influenza vaccines aims to tackle antigenic drift and shift and the rapid mutation rates of influenza viruses, thus providing broadly protective efficacy against multiple influenza virus strains.
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