Correlates of disease severity in bluetongue as a model of acute arbovirus infection

Most viral diseases display a variable clinical outcome due to differences in virus strain virulence and/or individual host susceptibility to infection. Understanding the biological mechanisms differentiating a viral infection displaying severe clinical manifestations from its milder forms can provide the intellectual framework toward therapies and early prognostic markers. This is especially true in arbovirus infections, where most clinical cases are present as mild febrile illness. Here, we used a naturally occurring vector-borne viral disease of ruminants, bluetongue, as an experimental system to uncover the fundamental mechanisms of virus-host interactions resulting in distinct clinical outcomes. As with most viral diseases, clinical symptoms in bluetongue can vary dramatically. We reproduced experimentally distinct clinical forms of bluetongue infection in sheep using three bluetongue virus (BTV) strains (BTV-1IT2006, BTV-1IT2013 and BTV-8FRA2017). Infected animals displayed clinical signs varying from clinically unapparent, to mild and severe disease. We collected and integrated clinical, haematological, virological, and histopathological data resulting in the analyses of 332 individual parameters from each infected and uninfected control animal. We subsequently used machine learning to select the key viral and host processes associated with disease pathogenesis. We identified and experimentally validated five different fundamental processes affecting the severity of bluetongue: (i) virus load and replication in target organs, (ii) modulation of the host type-I IFN response, (iii) pro-inflammatory responses, (iv) vascular damage, and (v) immunosuppression. Overall, we showed that an agnostic machine learning approach can be used to prioritise the different pathogenetic mechanisms affecting the disease outcome of an arbovirus infection

A machine learning framework to identify the correlates of disease severity in acute arbovirus infection

Most viral diseases display a variable clinical outcome due to differences in virus strain virulence and/or individual host susceptibility to infection. Understanding the biological mechanisms differentiating a viral infection displaying severe clinical manifestations from its milder forms can provide the intellectual framework toward therapies and early prognostic markers. This is especially true in arbovirus infections, where most clinical cases are present as mild febrile illness. Here, we used a naturally occurring vector-borne viral disease of ruminants, bluetongue, as an experimental system to uncover the fundamental mechanisms of virus-host interactions resulting in distinct clinical outcomes. As with most viral diseases, clinical symptoms in bluetongue can vary dramatically. We reproduced experimentally distinct clinical forms of bluetongue infection in sheep using three bluetongue virus (BTV) strains (BTV-1IT2006, BTV-1IT2013 and BTV-8FRA2017). Infected animals displayed clinical signs varying from clinically unapparent, to mild and severe disease. We collected and integrated clinical, haematological, virological, and histopathological data resulting in the analyses of 332 individual parameters from each infected and uninfected control animal. We subsequently used machine learning to identify the key viral and host processes associated with disease pathogenesis. We identified five different fundamental processes affecting the severity of bluetongue: (i) virus load and replication in target organs, (ii) modulation of the host type-I IFN response, (iii) pro-inflammatory responses, (iv) vascular damage, and (v) immunosuppression. Overall, our study using an agnostic machine learning approach, can be used to prioritise the different pathogenetic mechanisms affecting the disease outcome of an arbovirus infection.The authors thank all team members of the Histology Research Service of University of Glasgow: Lynn Stevenson, Frazer Bell, Lynn Oxford, Jan Duncan, and Jessica Lee for the outstanding quality of their work in the histology lab. We also thank Giovanni Antonio Pilo for his invaluable support in the field work. The work would not have been possible without the invaluable help for animal care of Berardo De Dominicis, Doriano Ferrari, Massimiliano Caporale, Giampaolo Foschini in Teramo and the teams in Sassari, Italy. This study was funded by the Wellcome Trust (206369/Z/17/Z) and in part by the EU (H2020 PALE-Blu grant project No: 727393-2), the Italian Ministry of Health (RC IZS SA 02/16 and RC IZS SA 04/18), a Research Fellowship by the Deutsche Forschungsgemeinschaft (DFG; Project number 406109949) and the Medical Research Council (MC_UU_00034/5).N

L’immunogenicità nella cavia e nel cavallo di due formulazioni di un vaccino inattivato e adiuvato per la peste equina

L’efficacia di due vaccini monovalenti, inattivati e adiuvati per il controllo della Peste Equina, allestiti con i sierotipi 5 e 9, è stata saggiata su cavia per selezionare la formulazione con le migliori capacità immunogene. Nella formulazione dei vaccini sono state prese in considerazione: la risposta immunitaria evocata nella cavia e le proprietà infiammatorie di due diversi tipi di adiuvanti precedentemente saggiati nella specie di destino del vaccino.Il vaccino allestito con il sierotipo 9, saggiato in uno studio pilota su cavallo, si è dimostrato capace fin dalla prima somministrazione di stimolare la produzione di anticorpi neutralizzanti. La risposta anticorpale evocata ha subito un marcato rialzo dopo la somministrazione della dose di richiamo, effettuata dopo 28 giorni, perdurando per almeno 10 mesi. La cavia sembra essere un utile modello di laboratorio per la valutazione delle proprietà antigeniche dei vaccini contro la peste equina

Immunogenicity of two adjuvant formulations of an inactivated African horse sickness vaccine in guinea-pigs and target animals

Monovalent, inactivated and adjuvanted vaccines against African horse sickness, prepared with serotypes 5 and 9, were tested on guinea-pigs to select the formulation that offered the greatest immunity. The final formulation of the vaccines took into account the immune response in the guinea-pig and the inflammatory properties of two types of adjuvant previously tested on target animals. A pilot study was subsequently conducted on horses using a vaccine prepared with serotype 9. The vaccine stimulated neutralising antibodies from the first administration and, after the booster dose, 28 days later; high antibody levels were recorded for at least 10 months. The guinea-pig appears to be a useful laboratory model for the evaluation of the antigenic properties of African horse sickness vaccines

Inactivated and adjuvanted vaccine for the control of the African horse sickness virus serotype 9 infection: evaluation of efficacy in horses and guinea-pig model

African horse sickness (AHS) is a non-contagious viral disease of solipeds transmitted by Culicoides. The disease is endemic in most African countries. Past experience has shown that Italy is a country exposed to emerging infectious diseases endemic to Africa; an incursion of AHS virus together with the widespread presence of Culicoides vectors could be the cause of a serious epidemic emergency. A live attenuated vaccine containing seven of the nine viral serotypes, serotype 5 and 9 are excluded, is commercially available from Onderstepoort Biological Products. However, the use of live vaccines is a matter of endless disputes, and therefore inactivated or recombinant alternative products have been investigated over the years. Since research on AHS is hampered by the use of horses to evaluate vaccine potency, in a previous experiment serological response to serotypes 5 and 9 was assayed in guinea-pigs and horses. A durable and comparable serological response was observed in the two animal species. In the present study antibody response in horses and guinea-pigs, immunised with the inactivated-adjuvanted vaccine formulated with serotype 9, was tested over a period of 12 months. When immunity was challenged, horses were protected from infection and disease. Antibody response in horses and guinea-pigs compared favourably

Vaccino inattivato e adiuvato per il controllo delle infezioni da sierotipo 9 del virus della peste equina: valutazione dell'efficacia in cavallo e cavia

La peste equina (PE) è una malattia virale non contagiosa dei solipedi trasmessa da insetti vettori appartenenti al genere Culicoides. La malattia è endemica in numerose regioni dell'Africa e passate esperienze hanno evidenziato come l'Italia sia un paese esposto alle malattie infettive emergenti, endemiche in Africa. Un'incursione del virus della PE unitamente alla presenza del vettore Culicoides potrebbero essere causa di una emergenza epidemica. Onderstepoort Biological Products (OBP) commercializza un vaccino vivo attenuato contenente 7 dei 9 sierotipi virali, i sierotipi 5 e 9 sono esclusi dal vaccino. L'uso di tali vaccini è controverso, pertanto, da diversi anni, vengono condotti studi su prodotti inattivati o ricombinanti. Poiché la ricerca sui vaccini PE è ostacolata dalla necessità di utilizzare il cavallo per la valutazione dell'immunogenicità, in un precedente esperimento è stata studiata la risposta sierologica ai sierotipi 5 e 9, in cavie e cavalli. Nelle due specie animali è stata osservata una risposta durevole e sovrapponibile. Nel presente studio sono state saggiate per un periodo di 12 mesi le risposte sierologiche ottenute in cavie e cavalli immunizzati con il vaccino inattivato formulato con il sierotipo 9. Le risposte sierologiche nelle due specie animali si sono confermate sovrapponibili. Al challenge dell'immunità i cavalli sono risultati protetti dall'infezione e dalla malattia

Efficacy of an inactivated EHDV-8 vaccine in preventing viraemia and clinical signs in experimentally infected cattle

Epizootic haemorrhagic disease (EHD), caused by the EHD virus (EHDV), is a vector-borne viral disease transmitted through Culicoides biting midges. EHDV comprises seven serotypes (1, 2, and 4–8), with EHDV-8 having recently emerged and spread in Europe over the last two years. Such event has raised concerns about the significant threat posed by EHDV-8 to livestock industry. In this study, an inactivated vaccine against EHDV-8 (vEHDV8-IZSAM) was developed. Safety and efficacy of the vaccine were evaluated in calves through clinical, serological, and virological monitoring following experimental challenge.The vaccine was proven safe, with only transient fever and localized reactions observed in a few animals, consistent with adjuvanted vaccine side effects. vEHDV8-IZSAM elicited a robust humoral response, as evidenced by the presence of neutralizing antibodies. After challenge with a virulent isolate, viraemia and clinical signs were evidenced in control animals but in none of the vaccinated animals.This study highlights the potential of vEHDV8-IZSAM as a safe and highly effective vaccine against EHDV-8 in cattle. It offers protection from clinical disease and effectively prevents viraemia. With the recent spread of EHDV-8 in European livestock, the use of an inactivated vaccine could be key in protecting animals from clinical disease and thus to mitigate the economic impact of the disease. Further investigations are warranted to assess the duration of the induced immunity and the applicability of this vaccine in real-world settings. Accordingly, joint efforts between public veterinary institutions and pharmaceutical companies are recommended to scale up vaccine production

SARS-CoV-2 antibodies in dogs and cats in a highly infected area of Brazil during the pandemic

: SARS-CoV-2 was a worldwide threat during the COVID-19 pandemic, and the state of Mato Grosso had the second highest mortality rate in Brazil, with 427. 4 deaths/100,000 inhabitants. However, no large-scale study among dogs and cats in such highly infected areas of Brazil has so far been conducted. Accordingly, the present study reports on a serosurvey among dogs and cats in Cuiabá, capital of Mato Grosso from November 2020 to July 2021, where the human mortality rate was 605/100,000 at that time. Overall, 33/762 dogs (4.3%) and 4/182 cats (2.2%) were found to be seropositive for SARS-CoV-2 through ELISA, and 3/762 dogs (0.4%) and 3/182 cats (1.6%) were seropositive through the serum neutralization test. Cats presented higher seroprevalence with higher titers of neutralizing antibodies. Although N-protein based ELISA may be a good screening test, cross-reactivity with other canine coronaviruses may impair its diagnostic use among dogs