SARS-CoV-2 in outdoor air following the third wave lockdown release, Portugal, 2021

Aiming to contribute with more data on the presence of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) in outdoor environments, we performed air sampling in outdoor terraces from restaurants in three major cities of Portugal in April 2021, following the third wave lockdown release in the country. Air samples (n=19) were collected in 19 restaurant terraces during lunch time. Each air sample was collected using a Coriolis Compact air sampler, followed by RNA extraction and real-time quantitative PCR for the detection of viral RNA. Viral viability was also assessed through RNAse pre-treatment of samples. Only one of the 19 air samples was positive for SARS-CoV-2 RNA, with 7337 gene copies m–3 for the genomic region N2, with no viable virus in this sample. The low number of positive samples found in this study is not surprising, as sampling took place in outdoor settings where air circulation is optimal, and aerosols are rapidly dispersed by the air currents. These results are consistent with previous reports stating that transmission of SARS-CoV-2 in outdoor spaces is low, although current evidence shows an association of exposures in settings where drinking and eating is possible on-site with an increased risk in acquiring SARS-CoV-2 infection. Moreover, the minimal infectious dose for SARS-CoV-2 still needs to be determined so that the real risk of infection in different environments can be accurately established.This work was supported by national funds, through Fundação para a Ciência e Tecnologia (FCT), under projects UIDB/04750/2020 and LA/P/0064/2020, and by LA/P/0045/2020 (ALiCE) and UIDB/00511/2020 – UIDP/00511/2020 (LEPABE) funded by national funds through FCT/MCTES (PIDDAC). This work was also supported by the AIRCOVID initiative and is financed by the EEA Grants Bilateral Relations Fund through the Agreement on the European Economic Area (EEE), Iceland, Liechtenstein and Norway, which are partners in the internal market with the States-Members of the European Union. As a way of promoting a continuous and balanced strengthening of economic and trade relations, the parties to the EEA Agreement established a multi-annual Financial Mechanism, known as EEA Grants. The EEA Grants aim to reduce social and economic disparities in Europe and strengthen bilateral relations between these three countries and the beneficiary countries. For the period 2014–2021, a total contribution of €2.8 billion has been agreed to 15 beneficiary countries. Portugal will benefit from an allocation ofThis work was supported by national funds, through Fundação para a Ciência e Tecnologia (FCT), under projects UIDB/04750/2020 and LA/P/0064/2020, and by LA/P/0045/2020 (ALiCE) and UIDB/00511/2020 – UIDP/00511/2020 (LEPABE) funded by national funds through FCT/MCTES (PIDDAC). This work was also supported by the AIRCOVID initiative and is financed by the EEA Grants Bilateral Relations Fund through the Agreement on the European Economic Area (EEE), Iceland, Liechtenstein and Norway, which are partners in the internal market with the States-Members of the European Union. As a way of promoting a continuous and balanced strengthening of economic and trade relations, the parties to the EEA Agreement established a multi-annual Financial Mechanism, known as EEA Grants. The EEA Grants aim to reduce social and economic disparities in Europe and strengthen bilateral relations between these three countries and the beneficiary countries. For the period 2014–2021, a total contribution of €2.8 billion has been agreed to 15 beneficiary countries. Portugal will benefit from an allocation of 102.7 million euros. Learn more at eeagrants.gov.pt. Priscilla Gomes da Silva thanks FCT for the financial support of her PhD work (2020.07806.BD, CRM: 0026504) contract through the DOCTORATES 4 COVID-19 program

The genetic architecture of helminth-specific immune responses in a wild population of Soay sheep (Ovis aries)

Much of our knowledge of the drivers of immune variation, and how these responses vary over time, comes from humans, domesticated livestock or laboratory organisms. While the genetic basis of variation in immune responses have been investigated in these systems, there is a poor understanding of how genetic variation influences immunity in natural, untreated populations living in complex environments. Here, we examine the genetic architecture of variation in immune traits in the Soay sheep of St Kilda, an unmanaged population of sheep infected with strongyle gastrointestinal nematodes. We assayed IgA, IgE and IgG antibodies against the prevalent nematode Teladorsagia circumcincta in the blood plasma of > 3,000 sheep collected over 26 years. Antibody levels were significantly heritable (h2 = 0.21 to 0.57) and highly stable over an individual’s lifespan. IgA levels were strongly associated with a region on chromosome 24 explaining 21.1% and 24.5% of heritable variation in lambs and adults, respectively. This region was adjacent to two candidate loci, Class II Major Histocompatibility Complex Transactivator (CIITA) and C-Type Lectin Domain Containing 16A (CLEC16A). Lamb IgA levels were also associated with the immunoglobulin heavy constant loci (IGH) complex, and adult IgE levels and lamb IgA and IgG levels were associated with the major histocompatibility complex (MHC). This study provides evidence of high heritability of a complex immunological trait under natural conditions and provides the first evidence from a genome-wide study that large effect genes located outside the MHC region exist for immune traits in the wild

Avian mycoplasmosis update

Avian mycoplasmas occur in a variety of bird species. The most important mycoplasmas for chickens and turkeys are Mycoplasma gallisepticum (MG), M. synoviae (MS), and M. meleagridis. Besides, M. iowe (MI) is an emerging pathogen in turkeys, but of little concern for chickens. Mycoplasmas are bacteria that lack cell wall and belong to the class Mollicutes. Although they have been considered extracellular agents, scientists admit nowadays that some of them are obligatory intracellular microorganisms, whereas all other mycoplasmas are considered facultative intracellular organisms. Their pathogenic mechanism for disease include adherence to host target cells, mediation of apoptosis, innocent bystander damage to host cell due to intimate membrane contact, molecular (antigen) mimicry that may lead to tolerance, and mitotic effect for B and/or T lymphocytes, which could lead to suppressed T-cell function and/or production of cytotoxic T cell, besides mycoplasma by-products, such as hydrogen peroxide and superoxide radicals. Moreover, mycoplasma ability to stimulate macrophages, monocytes, T-helper cells and NK cells, results in the production of substances, such as tumor necrosing factor (TNF-alpha), interleukin (IL-1, 2, 6) and interferon (<FONT FACE=Symbol>a, b, g</FONT>). The major clinical signs seen in avian mycoplasmosis are coughing, sneezing, snicks, respiratory rales, ocular and nasal discharge, decreased feed intake and egg production, increased mortality, poor hatchability, and, primarily in turkeys, swelling of the infraorbital sinus(es). Nevertheless, chronic and unapparent infections are most common and more threatening. Mycoplasmas are transmitted horizontally, from bird to bird, and vertically, from dam to offspring through the eggs. Losses attributed to mycoplasmosis, mainly MG and MS infections, result from decreased egg production and egg quality, poor hatchability (high rate of embryonic mortality and culling of day-old birds), poor feed efficiency, increase in mortality and carcass condemnations, besides medication costs. Mycoplasmas are diagnosed by serologic tests, culture and PCR and are sensitive to antimicrobials whose action sites are other than the bacterial cell wall, such as tetracyclines, macrolides, quinolones and tiamulin. However, mycoplasma control is more efficiently achieved by acquisition of birds free of MG, MS, MM and/or MI, vaccination of layers, and monitoring of breeder flocks, followed by elimination of the infected flocks that are detected