Uhart, M. M. | bioRxiv Science

bioRxiv2023

Highly pathogenic avian influenza A (H5N1) in marine mammals and seabirds in Peru

Highly pathogenic avian influenza (HPAI) A/H5N1 viruses (lineage 2.3.4.4b) are rapidly invading the Americas, threatening wildlife, poultry, and potentially evolving into the next global pandemic. In November 2022, HPAI arrived in Peru, where massive pelican and sea lion die-offs are still underway. We report complete genomic characterization of HPAI/H5N1 viruses in five species of marine mammals and seabirds (dolphins, sea lions, sanderlings, pelicans and cormorants) sampled since November 2022. All Peruvian viruses belong to the HPAI A/H5N1 lineage 2.3.4.4b, but they are 4:4 reassortants where 4 genomic segments (PA, HA, NA and MP) position within the Eurasian lineage that initially entered North America from Eurasia, while the other 4 genomic segments (PB2, PB1, NP and NS) position within the American lineage (clade C) that was already circulating in North America. These viruses are rapidly accruing mutations as they spread south. Peruvian viruses do not contain PB2 E627K or D701N mutations linked to mammalian host adaptation and enhanced transmission, but at least 8 novel polymorphic sites warrant further examination. This is the first report of HPAI A/H5N1 in marine birds and mammals from South America, highlighting an urgent need for active local surveillance to manage outbreaks and limit spillover into humans.

genomics↗

bioRxiv2021

Sarcoptic mange outbreak decimates South American camelid populations in San Guillermo National Park, Argentina

Sarcoptic mange epidemics can devastate wildlife populations. In 2014, mange was first detected in vicuna (Vicugna vicugna) and guanaco (Lama guanicoe) in San Guillermo National Park (SGNP), Argentina. This study characterized the potential source and the impacts of the outbreak in 2017-2019. Transect surveys indicated a sharp decrease in the density of live vicuna and guanaco by 68% and 77%, respectively, from May 2017 to June 2018. By April 2019 no vicuna or guanaco were recorded on transect surveys, suggesting a near-extinction at the local level. Clinical signs consistent with mange (e.g. intense pruritus, hyperkeratosis, alopecia) were observed in 24% of live vicuna (n = 478) and 33% of live guanaco (n = 12) during surveys, as well as in 94% of vicuna carcasses (n = 124) and 85% of guanaco carcasses (n = 20) opportunistically examined during the study period. Histological examination (n = 15) confirmed sarcoptic mange as the cause of the cutaneous lesions. Genetic characterization revealed that Sarcoptes scabiei recovered from seven vicuna (n = 13) and three guanaco (n = 11) shared the same genotype, which is consistent with a single source and recent origin of the epidemic. A governmental livestock incentive program introduced llama (Lama glama) in areas adjacent to SGNP in 2009, some of which reportedly had alopecic scaling consistent with sarcoptic mange. We hypothesize that the introduction of mange-infected llama may have triggered the outbreak in wild camelids which has now put them at a high risk of local extinction. This unprecedented event highlights that the accidental introduction of disease may be underestimated at the onset yet can have devastating effects on native ungulate populations with potentially profound effects at the community and ecosystem levels.

zoology↗