Epidemiology of Deltacoronaviruses (δ-CoV) and Gammacoronaviruses (γ-CoV) in Wild Birds in the United States

Abstract

Porcine deltacoronavirus (δ-CoV) is the object of extensive research in several countries including the United States. In contrast, the epidemiology of δ-CoVs in wild birds in the US is largely unknown. Our aim was to comparatively assess the prevalence of δ- and γ-CoVs in wild migratory terrestrial and aquatic birds in Arkansas, Illinois, Indiana, Maryland, Mississippi, Missouri, Ohio, Tennessee and Wisconsin. A total of 1236 cloacal/fecal swabs collected during the period 2015–2018 were tested for γ- and δ-CoVs using genus-specific reverse transcription-PCR assays. A total of 61 (4.99%) samples were γ-CoV positive, with up to 29 positive samples per state. In contrast, only 14 samples were positive for δ-CoV (1.14%) with only 1–4 originating from the same state. Thus, unlike previous reports from Asia, γ-CoVs are more prevalent than δ-CoVs in the US, suggesting that δ-CoVs may spread in birds with lower efficiency. This may indicate δ-CoV emerging status and incomplete adaptation to new host species limiting its spread. Phylogenetic analysis of the partial N gene revealed that the newly identified δ-CoV strains were most closely related to the HKU20 (wigeon) strain. Further studies are necessary to investigate the role of aquatic bird δ-CoVs in the epidemiology of δ-CoVs in swine and terrestrial birds.

Wild birds as reservoirs for diverse and abundant gamma- and deltacoronaviruses

“… 2018 ; Paim et al . 2019 ; Table 1 ). These continue to reveal a high frequency of gammacoronaviruses in waterfowl, suggesting it is a true observation.…”

“…Similarly, a recent study from the USA sequenced the N gene, and comparisons of these data were limited to deltacoronaviruses for which there are full genome sequences (Paim et al . 2019 ). By far the largest number of sequences available are of a short fragment of the RdRp.…”

The 2020 race towards SARS-CoV-2 specific vaccines

“…One of the most dangerous features of coronaviruses is their capability to break through the species barrier. In this regard, a plethora of reports demonstrated transfers from wild to domestic birds and some species of mammals, including even marine mammals 16 , 17 .…”

Animal coronaviruses and coronavirus disease 2019: Lesson for One Health approach

“…Especially birds of younger age groups are highly susceptible, causing massive economic losses to the global poultry industry (Dhama et al, 2014;Smith et al, 2015). After the introduction of the virus in the birds through different routes, like feco-oral route and airborne transmission, (Dhama et al, 2014) Delta Coronavirus Bulbul coronavirus HKU11 (Paim et al, 2019) Wigeon coronavirus HKU20…”

“…Canine Alpha Coronavirus CCoV-I (Escutenaire et al, 2007;Licitra et al, the virus usually replicates in ciliated epithelial cells of the respiratory tract and causes severe respiratory infections, like coughing, nasal discharge, rales, gasping, swollen sinus, and also affects the digestive, reproductive, and urogenital tract, resulting in nephritis and egg drop syndrome (Weiss and Navas-Martin, 2005;Fan et al, 2018). Other CoVs from the deltacoronavirus genus include Bulbul coronavirus HKU11, Wigeon coronavirus HKU20, White-eye coronavirus HKU16, Common moorhen coronavirus HKU21, Munia coronavirus HKU13, and Night-heron coronavirus HKU19 that can severely infect birds with more complications (Paim et al, 2019). Even though there were different attempts for effective vaccine development against the CoVs, the rapid mutations and antigenic variations created a hindrance to successfully trigger the local immune response and cure infections (Saif, 2020;Zhang et al, 2020b).…”