[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]
BMC Infect Dis. 2018 Jul 6;18(1):314. doi: 10.1186/s12879-018-3222-6.
Unlocking pandemic potential: prevalence and spatial patterns of key substitutions in avian influenza H5N1 in Egyptian isolates.
Young SG1, Kitchen A2, Kayali G3,4, Carrel M5,6.
Author information: 1 Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR, USA. SGYoung@uams.edu. 2 Department of Anthropology, University of Iowa, Iowa City, IA, USA. 3 Department of Epidemiology, Human Genetics, and Environmental Sciences, University of Texas Health Sciences Center, Houston, TX, USA. 4 Department of Scientific Research, Human Link, Hazmieh, Lebanon. 5 Department of Geographical and Sustainability Sciences, University of Iowa, Iowa City, IA, USA. 6 Department of Epidemiology, University of Iowa, Iowa City, IA, USA.
Avian influenza H5N1 has a high human case fatality rate, but is not yet well-adapted to human hosts. Amino acid substitutions currently circulating in avian populations may enhance viral fitness in, and thus viral adaptation to, human hosts. Substitutions which could increase the risk of a human pandemic (through changes to host specificity, virulence, replication ability, transmissibility, or drug susceptibility) are termed key substitutions (KS). Egypt represents the epicenter of human H5N1 infections, with more confirmed cases than any other country. To date, however, there have not been any spatial analyses of KS in Egypt.
Using 925 viral samples of H5N1 from Egypt, we aligned protein sequences and scanned for KS. We geocoded isolates using dasymetric mapping, then carried out geospatial hot spot analyses to identify spatial clusters of high KS detection rates. KS prevalence and spatial clusters were evaluated for all detected KS, as well as when stratified by phenotypic consequence.
A total of 39 distinct KS were detected in the wild, including 17 not previously reported in Egypt. KS were detected in 874 samples (94.5%). Detection rates varied by viral protein with most KS observed in the surface hemagglutinin (HA) and neuraminidase (NA) proteins, as well as the interior non-structural 1 (NS1) protein. The most frequently detected KS were associated with increased viral binding to mammalian cells and virulence. Samples with high overall detection rates of KS exhibited statistically significant spatial clustering in two governorates in the northwestern Nile delta, Alexandria and Beheira.
KS provide a possible mechanism by which avian influenza H5N1 could evolve into a pandemic candidate. With numerous KS circulating in Egypt, and non-random spatial clustering of KS detection rates, these findings suggest the need for increased surveillance in these areas.
KEYWORDS: Avian influenza; Egypt; Landscape genetics; Poultry
PMID: 29980172 PMCID: PMC6035396 DOI: 10.1186/s12879-018-3222-6 [Indexed for MEDLINE] Free PMC Article
Keywords: Avian Influenza; H5N1; Pandemic Preparedness; Egypt.