Double-blinded, randomised, placebo-controlled trial of convalescent plasma for COVID-19: analyses by neutralising antibodies homologous to recipients' variants.

INTRODUCTION: Convalescent plasma (CP) emerged as potential treatment for COVID-19 early in the pandemic. While efficacy in hospitalised patients has been lacklustre, CP may be beneficial at the first stages of disease. Despite multiple new variants emerging, no trials have involved analyses on variant-specific antibody titres of CP. METHODS: We recruited hospitalised COVID-19 patients within 10 days of symptom onset and, employing a double-blinded approach, randomised them to receive 200 ml convalescent plasma with high (HCP) or low (LCP) neutralising antibody (NAb) titre against the ancestral strain (Wuhan-like variant) or placebo in 1:1:1 ratio. Primary endpoints comprised intubation, corticosteroids for symptom aggravation, and safety assessed as serious adverse events. For a preplanned ad hoc analysis, the patients were regrouped by infused CP's NAb titers to variants infecting the recipients i.e. by titres of homologous HCP (hHCP) or LCP (hLCP). RESULTS: Of the 57 patients, 18 received HCP, 19 LCP and 20 placebo, all groups smaller than planned. No significant differences were found for primary endpoints. In ad hoc analysis, hHCPrecipients needed significantly less respiratory support, and appeared to be given corticosteroids less frequently (1/14; 7.1%) than those receiving hLCP (9/23; 39.1%) or placebo (8/20; 40%), (p = 0.077). DISCUSSION: Our double-blinded, placebo-controlled CP therapy trial remained underpowered and does not allow any firm conclusions for early-stage hospitalised COVID-19 patients. Interestingly, however, regrouping by homologous - recipients' variant-specific - CP titres suggested benefits for hHCP. We encourage similar re-analysis of ongoing/previous larger CP studies. TRIAL REGISTRATION: ClinTrials.gov identifier: NCT0473040.

Necropsy-based study on dairy cow mortality-Underlying causes of death.

The worldwide problem of increasing dairy cow mortality is widespread in modern production systems, it causes economic losses, and indicates problems with herd health and welfare. Most studies on causes of dairy cow mortality are limited as they are based on secondary register data, or questionnaires for producers or veterinarians, and neither necropsies nor histopathologic analyses are usually performed. For this reason, no definite causes for dairy cow deaths have been determined making it difficult or impossible to implement effective preventive measures. The objectives of this study were to (1) determine the causes of on-farm mortality of Finnish dairy cows, (2) determine the usefulness of routine histopathologic analysis in bovine necropsies, and (3) assess how reliable producers' perception about the cause of death is. Underlying diagnoses of on-farm deaths were determined through necropsy of 319 dairy cows at an incineration plant. The necropsy data were combined with background information obtained from online questionnaires covering cow and herd records. Mastitis was the most common underlying diagnosis of death (26.6%), followed by digestive disorders (15.4%), other known disorders (13.8%), calving-associated disorders (12.2%), and locomotion disorders (11.9%). The underlying diagnoses of death varied during different stages of lactation and with parity. A large proportion of the study cows (46.7%) died during the first 30 d after calving, and of those, 63.6% died during the first 5 d. A routine histopathologic analysis was performed in every necropsy, and it changed the preliminary gross diagnosis in 18.2% of the cases. Producers' perception about the cause of death agreed with the necropsy-based underlying diagnosis of death in 42.8% of the cases. It was most consistent for mastitis, calving disorders, locomotion diseases, and accidents. In cases where producers had no insights about the cause of death, necropsy revealed the final underlying diagnosis in 88.2% of cases, demonstrating the usefulness of necropsy. Based on our findings, necropsies provide useful and reliable information to develop control programs for cow mortality. Including routine histopathologic analysis in necropsies, more accurate information may be obtained. Furthermore, targeting preventive measures on transitional cows may be most effective, as the number of deaths was highest at this time.

Mechanisms behind the varying severity of Aleutian mink disease virus: Comparison of three farms with a different disease status.

Aleutian mink disease virus (AMDV) is distributed widely among mink farms and wild mustelids despite ongoing attempts to stop the spread. The severity of Aleutian disease (AD) varies from subclinical to fatal but the reasons for its varying severity are complex and unclear. Recently, breeding of tolerant mink has drawn attention as the possible solution to reduce the effects of AD in farms. The aim of this study was to gather information on the effects of breeding based on overall health, production traits, and antibody titer on AD severity by comparing a positive farm (farm 1) that has been breeding for tolerance in mink to an infected farm without tolerance selection, and an AMDV-free farm. During the 2.5-year follow-up, the mink in farm 1 remained mostly free of clinical AD, had normal pelt quality and litter size, and had low virus copy numbers in tissues and low antibody titers in ELISA. In histopathological studies, most of the farm 1 mink had no/mild lesions in their kidneys. 29-43% of the mink were ELISA negative but PCR positive throughout the follow-up and frequent changes in virus strains and coinfections were observed. Several differences in gene expression between animals from different farms were also detected. These results indicate that the disease burden of AMDV can be reduced, with seemingly normal health and production rates, despite continual circulation of ADMV in cases where eradication attempts are unsuccessful.

Arenavirus Coinfections Are Common in Snakes with Boid Inclusion Body Disease.

Recently, novel arenaviruses were found in snakes with boid inclusion body disease (BIBD); these form the new genus Reptarenavirus within the family Arenaviridae. We used next-generation sequencing and de novo sequence assembly to investigate reptarenavirus isolates from our previous study. Four of the six isolates and all of the samples from snakes with BIBD contained at least two reptarenavirus species. The viruses sequenced comprise four novel reptarenavirus species and a representative of a new arenavirus genus.

Recent increase in prevalence of antibodies to Dobrava-Belgrade virus (DOBV) in yellow-necked mice in Northern Italy.

Dobrava-Belgrade virus (DOBV) is the most pathogenic hantavirus in Europe with a case-fatality rate of up to 12%. To detect changes in risk for humans, the prevalence of antibodies to DOBV has been monitored in a population of Apodemus flavicollis in the province of Trento (northern Italy) since 2000, and a sudden increase was observed in 2010. In the 13-year period of this study, 2077 animals were live-trapped and mean hantavirus seroprevalence was 2·7% (s.e. = 0·3%), ranging from 0% (in 2000, 2002 and 2003) to 12·5% (in 2012). Climatic (temperature and precipitation) and host (rodent population density, rodent weight and sex, and larval tick burden) variables were analysed using Generalized Linear Models and multi-model inference to select the best model. Climatic changes (mean annual precipitation and maximum temperature) and individual body mass had a positive effect on hantavirus seroprevalence. Other possible drivers affecting the observed pattern need to be studied further.

Aleutian mink disease virus in free-ranging mustelids in Finland - a cross-sectional epidemiological and phylogenetic study.

Aleutian mink disease virus (AMDV) can cause severe immune-complex-mediated disease in American mink. AMDV has also been detected in several other mustelid species with potential negative impact on their health and population. A molecular and cross-sectional epidemiological study was conducted to obtain data on the prevalence, distribution, transmission and diversity of AMDV strains in Finnish free-ranging mustelids and risk factors associated with infection. The presence of anti-AMDV antibodies and/or AMDV DNA was tested from 308 samples representing eight mustelid species and 17 administrative regions. Positive samples were detected across Finland, and in 54 % (31/57) of feral American mink, 27 % (7/26) of European badgers and 7 % (1/14) of European polecats. Samples from Eurasian otters, European pine martens, least weasels, stoat and wolverine were negative. Major risk factors for infection were the species American mink with 335 and badger with 74 times higher odds than other species, and the years 2006-2009 with five times higher odds than the years 2010-2014. No clustering according to species, geographical origin or year was evident in phylogeny, except for four divergent sequences from Estonian badgers that formed a separate phylogroup distinct from other AMDV strains. This study showed that AMDV was prevalent in certain species of Finnish free-ranging mustelids and widely distributed across Finland. Furthermore, the free-ranging mustelids carried both strains similar to those found in farmed mink, but also distinct strains that may represent novel amdoparvoviruses.

Molecular detection of Bartonella spp. in deer ked pupae, adult keds and moose blood in Finland.

The deer ked (Lipoptena cervi) is a haematophagous ectoparasite of cervids that harbours haemotrophic Bartonella. A prerequisite for the vector competence of the deer ked is the vertical transmission of the pathogen from the mother to its progeny and transstadial transmission from pupa to winged adult. We screened 1154 pupae and 59 pools of winged adult deer keds from different areas in Finland for Bartonella DNA using PCR. Altogether 13 pupa samples and one winged adult deer ked were positive for the presence of Bartonella DNA. The amplified sequences were closely related to either B. schoenbuchensis or B. bovis. The same lineages were identified in eight blood samples collected from free-ranging moose. This is the first demonstration of Bartonella spp. DNA in a winged adult deer ked and, thus, evidence for potential transstadial transmission of Bartonella spp. in the species.

Diversity and composition of dengue virus type 2 in Venezuela.

Dengue is a mosquito-borne disease caused by four closely related dengue virus (genus Flavivirus)serotypes (DENV-1­4). The clinical outcomes vary from mild febrile illness to life-threatening haemorrhagic manifestations. DENVs are endemic in the tropics and subtropics globally and currently no specific treatment or vaccines are available. In Venezuela, the American-Asian genotype of DENV-2 is the most prevalent and has been associated with severe disease outcomes.We aimed to follow-up the molecular epidemiology of DENV-2 in Venezuela to investigate if the evolution of the virus has remained the same throughout time or if the same dynamics documented in Brazil (hyperendemic co-circulation) also occurred. The results show that whereas the epidemiology of DENV in several endemic areas is characterized by serotype replacements through time, in Venezuela the American-Asian genotype DENV-2 has evolved into several genetic lineages and has remained in hyperendemic co-circulation with the other serotypes.

Molecular evolution of Puumala hantavirus.

Puumala virus (PUUV) is a negative-stranded RNA virus in the genus Hantavirus, family Bunyaviridae. In this study, detailed phylogenetic analysis was performed on 42 complete S segment sequences of PUUV originated from several European countries, Russia, and Japan, the largest set available thus far for hantaviruses. The results show that PUUV sequences form seven distinct and well-supported genetic lineages; within these lineages, geographical clustering of genetic variants is observed. The overall phylogeny of PUUV is star-like, suggesting an early split of genetic lineages. The individual PUUV lineages appear to be independent, with the only exception to this being the Finnish and the Russian lineages that are closely connected to each other. Two strains of PUUV-like virus from Japan form the most ancestral lineage diverging from PUUV. Recombination points within the S segment were searched for and evidence for intralineage recombination events was seen in the Finnish, Russian, Danish, and Belgian lineages of PUUV. Molecular clock analysis showed that PUUV is a stable virus, evolving slowly at a rate of 0.7 x 10(-7) to 2.2 x 10(-6) nt substitutions per site per year.