A new influenza virus, genus D, isolated in US pigs and cattle, has also been circulating in cattle in France. It was first identified there in 2011, and an increase was detected in 2014. The virus genome in France is 94%–99% identical to its US counterpart, which suggests intercontinental spillover.

Bovine respiratory disease (BRD) is one of the most important diseases impacting the global cattle industry, resulting in significant economic loss. Commonly referred to as shipping fever, BRD is especially concerning for young calves during transport when they are most susceptible to developing disease. Despite years of extensive study, managing BRD remains challenging as its aetiology involves complex interactions between pathogens, environmental and host factors. While at the beginning of the twentieth century, scientists believed that BRD was only caused by bacterial infections (“bovine pasteurellosis”), we now know that viruses play a key role in BRD induction. Mixtures of pathogenic bacteria and viruses are frequently isolated from respiratory secretions of animals with respiratory illness. The increased diagnostic screening data has changed our understanding of pathogens contributing to BRD development. In this review, we aim to comprehensively examine experimental evidence from all existing studies performed to understand coinfections between respiratory pathogens in cattle. Despite the fact that pneumonia has not always been successfully reproduced by in vivo calf modelling, several studies attempted to investigate the clinical significance of interactions between different pathogens. The most studied model of pneumonia induction has been reproduced by a primary viral infection followed by a secondary bacterial superinfection, with strong evidence suggesting this could potentially be one of the most common scenarios during BRD onset. Different in vitro studies indicated that viral priming may increase bacterial adherence and colonization of the respiratory tract, suggesting a possible mechanism underpinning bronchopneumonia onset in cattle. In addition, a few in vivo studies on viral coinfections and bacterial coinfections demonstrated that a primary viral infection could also increase the pathogenicity of a secondary viral infection and, similarly, dual infections with two bacterial pathogens could increase the severity of BRD lesions. Therefore, different scenarios of pathogen dynamics could be hypothesized for BRD onset which are not limited to a primary viral infection followed by a secondary bacterial superinfection.

Influenza D virus has been identified in America, Europe, and Asia. We detected influenza D virus antibodies in cattle and small ruminants from North (Morocco) and West (Togo and Benin) Africa. Dromedary camels in Kenya harbored influenza C or D virus antibodies, indicating a potential new host for these viruses.

H9N2 avian influenza viruses continue to spread in poultry and wild birds worldwide. Morocco just faced its first H9N2 influenza virus outbreaks early 2016 affecting different types of poultry production. After its introduction, the virus spread very rapidly throughout the country. Samples were collected from 11 chicken flocks with high morbidity and mortality rates. Four viruses were successfully isolated from broiler chickens and one from broiler breeders and fully sequenced. Phylogenetic and molecular markers analyses showed the Moroccan viruses belonged to the G1 lineage and likely originated from the Middle East. As known for H9N2 viruses, the Moroccanisolates possess several genetic markers that enhance virulence in poultry and transmission to humans. The present study demonstrated that under field conditions H9N2 could have a devastating effect on egg production and mortalities and highlighted a lack of surveillance data on the pathogen in the region.

Influenza D virus (IDV) has first been identified in 2011 in the USA and was shown to mainly circulate in cattle. While IDV is associated with mild respiratory signs, its prevalence is still unknown. In the present study we show that IDV has been circulating throughout France in cattle and small ruminants, with 47.2% and 1.5% seropositivity, respectively. The high prevalence and moderate pathogenicity of IDV in cattle suggest that it may play an initiating role in the bovine respiratory disease complex.

SUMMARY Low pathogenic avian influenza virus (LPAIV) usually causes mild disease or asymptomatic infection in poultry. LPAIV has, however, become a great threat to poultry industry due to mixed infections with other pathogens. Coinfections do frequently occur in the field but are not easily detected, and their impact on pathobiology is not clearly defined due to their complicated nature, but it is well known that there is an impact. One way to increase our knowledge of coinfections in poultry is to challenge birds in experimental and controlled conditions. While many articles report in vivo experiments with LPAIV in avian models, only a few have studied coinfections. Moreover, researchers tend to choose different bird types, ages, inoculation routes, and doses for their experiments, making it difficult to compare between studies. This review describes the state of the art for experimental infections with LPAIV alone or associated with coinfecting pathogens in avian models. It also discusses how best to mi... RESUMEN Estudio Recapitulativo. Influenza aviar de baja patogenicidad y patógenos co-infectantes: Revisión de las infecciones experimentales en modelos aviares. Los virus de la influenza aviar de baja patogenicidad (con las siglas en inglés LPAIV) generalmente causan enfermedad leve o infección asintomática en las aves comerciales. Sin embargo, los virus de la influenza aviar de baja patogenicidad se han convertido en una gran amenaza para la industria avícola debido a infecciones mixtas con otros patógenos. Las co-infecciones ocurren con frecuencia en el campo pero no son detectadas fácilmente y su impacto en la patobiología de estos virus no está claramente definido debido a su naturaleza complicada, pero se reconoce que existe un impacto. Una forma de aumentar el conocimiento de las co-infecciones en las aves comerciales es desafiar a las aves en condiciones experimentales y controladas. Mientras que muchos artículos reportan experimentos in vivo con virus de la influenza aviar de baja patogenicidad en...