Phylogeographic Dynamics of H9N2 Avian Influenza Viruses in Tunisia.

Avian influenza virus subtype H9N2 is endemic in commercial poultry in Tunisia. This subtype affects poultry and wild birds in Tunisia and poses a potential zoonotic risk. Tunisian H9N2 strains carry, in their hemagglutinins, the human-like marker 226 L that is most influential in avian-to-human viral transmission. For a better understanding of how ecological aspects of the H9N2 virus and its circulation in poultry, migratory birds and environment shapes the spread of the dissemination of H9N2 in Tunisia, herein, we investigate the epidemiological, evolutionary and zoonotic potential of seven H9N2 poultry isolates and sequence their whole genome. Phylogeographic and phylodymanic analysis were used to examine viral spread within and among wild birds, poultry and environment at geographical scales. Genetic evolution results showed that the eight gene sequences of Tunisian H9N2 AIV were characterized by molecular markers involved with virulence and mammalian infections. The geographical distribution of avian influenza virus appears as a network interconnecting countries in Europe, Asia, North Africa and West Africa. The spatiotemporal dynamics analysis showed that the H9N2 virus was transmitted from Tunisia to neighboring countries notably Libya and Algeria. Interestingly, this study also revealed, for the first time, that there was a virus transmission between Tunisia and Morocco. Bayesian analysis showed exchanges between H9N2 strains of Tunisia and those of the Middle Eastern countries, analysis of host traits showed that duck, wild birds and environment were ancestry related to chicken. The subtypes phylodynamic showed that PB1 segment was under multiple inter-subtype reassortment events with H10N7, H12N5, H5N2 and H6N1 and that PB2 was also a subject of inter-subtype reassortment with H10N4.

Phylogenetic and phylodynamic analyses of subtype-B metapneumovirus from chickens in Tunisia.

Swollen Head Syndrome (SHS) is an economically important viral disease of chickens caused by avian metapneumovirus (aMPV). The virus comprises 6 different subtypes (A,B,C,D, New-1 and New-2). To date, no information was available on the presence of the virus in Tunisian poultry. The present work aims to detect the presence of (aMPV) in broiler chicken in Tunisia, then to characterise the isolates in order to determine their subtype and to estimate their geographic origin of introduction. A total of 289 samples were collected, aMPV detection was detected by real time RT-PCR and molecular characterization was warried out by Sanger sequencing on the glycoprotein (G) gene. Phylogenetic analysis was carried out using Beast 2 software. Out of the 289 samples, 21 were revealed positive to aMPV. Only 2 isolates have been confirmed by sequencing analysis ; one isolate sampled in 2015 and another in 2019. Based on the partial G gene sequence, analysis of these 2 Tunisian isolates showed that they belong to subtype B. The isolate sampled in 2015, appeared to be phylogenetically related to derived vaccine strain. However, the one sampled in 2019 appeared to be a field strain. Phylodynamic analysis provided evidence that this field strain derived from a Spanish strain and probably the virus has been introduced from Spain to North Africa back in 2016. This study is the first that highlighted the circulation of (aMPV) in Tunisia. It is possible that aMPV has been circulating in Tunisia and neighboring countries without being detected. Also, multiple strains could be present and therefore multiple introductions have happened. Through this study, we shed the light on the importance of reinforcing farms biosecurity as well as virological surveillance.

Epidemiological and Phylogeographic Study of Equid Herpesviruses in Tunisia.

Equid herpesvirus (EHV) is a contagious viral disease affecting horses, causing illness characterized by respiratory symptoms, abortion and neurological disorders. It is common worldwide and causes severe economic losses to the equine industry. The present study was aimed at investigating the incidence of EHVs, the genetic characterization of Tunisian isolates and a spatiotemporal study, using 298 collected samples from diseased and clinically healthy horses. The global incidence of EHV infection was found to be about 71.81%. EHV2 and EHV5 were detected in 146 (48.99%) and 159 (53.35%) sampled horses, respectively. EHV1 was detected in 11 samples (3.69%); EHV4 was not detected. Co-infections with EHV1-EHV2, EHV1-EHV5 and EHV2-EHV5 were observed in 0.33%, 1.34% and 31.54% of tested horses, respectively. Phylogenetic analyses showed that gB of EHV2 and EHV5 displays high genetic diversity with a nucleotide sequence identity ranging from 88 to 100% for EHV2 and 97.5 to 100% for EHV5. Phylogeography suggested Iceland and USA as the most likely countries of origin of the Tunisian EHV2 and EHV5 isolates. These viruses detected in Tunisia seemed to be introduced in the 2000s. This first epidemiological and phylogeographic study is important for better knowledge of the evolution of equid herpesvirus infections in Tunisia.