Abstract
Viral enteric pathogens continuously burden intensive pig farming, causing gastrointestinal diseases of epidemic and endemic nature. The present study investigated two diarrhoea outbreaks on ...a large farrow-to-finish holding and subsequent circulation of outbreak-related enteric viruses. These viruses were characterised by whole genome sequencing, and statistical evaluation of the impact on specific production metrics was performed. The results provided evidence that the
Porcine epidemic diarrhoea virus
–swine enteric coronavirus (PEDV–SeCoV) S gene recombinant strain was responsible for the first outbreak, whilst
Rotavirus A
(RVA) in a mixed infection with
Rotavirus B
(RVB) and porcine kobuvirus (PKV) probably caused the second diarrhoea outbreak. Whole genome characterisation revealed a porcine origin of all viruses involved and significant heterogeneity of RVB strain, proposing four novel genotypes and changes in RVB VP1 genotype classification. The statistical evaluation confirmed only a minor disturbance in the number of weaned pigs per sow, with statistical forecasting showing positive trends. A follow-up study corroborated the endemicity of RVA and PKV, in contrast to PEDV–SeCoV. Punctual, comprehensive and timely investigation of diarrhoea outbreaks is a prerequisite for applying adequate pig health and biosecurity management. Calculating such outbreaks' impact on production metrics can potentially shape future decisions on management improvements.
As a leading viral cause of acute gastroenteritis in both humans and pigs, rotavirus A (RVA) poses a potential public health concern. Although zoonotic spillover of porcine RVA strains to humans is ...sporadic, it has been detected worldwide. The origin of chimeric human-animal strains of RVA is closely linked to the crucial role of mixed genotypes in driving reassortment and homologous recombination, which play a major role in shaping the genetic diversity of RVA. To better understand how genetically intertwined porcine and zoonotic human-derived G4P6 RVA strains are, the present study employed a spatiotemporal approach to whole-genome characterization of RVA strains collected during three consecutive RVA seasons in Croatia (2018-2021). Notably, sampled children under 2 years of age and weanling piglets with diarrhea were included in the study. In addition to samples tested by real-time RT-PCR, genotyping of VP7 and VP4 gene segments was conducted. The unusual genotype combinations detected in the initial screening, including three human and three porcine G4P6 strains, were subjected to next-generation sequencing, followed by phylogenetic analysis of all gene segments, and intragenic recombination analysis. Results showed a porcine or porcine-like origin for each of the eleven gene segments in all six RVA strains. The G4P6 RVA strains detected in children most likely resulted from porcine-to-human interspecies transmission. Furthermore, the genetic diversity of Croatian porcine and porcine-like human G4P6 strains was propelled by reassortment events between porcine and porcine-like human G4P6 RVA strains, along with homologous intragenotype and intergenotype recombinations in VP4, NSP1, and NSP3 segments. Described concurrent spatiotemporal approach in investigating autochthonous human and animal RVA strains is essential in drawing relevant conclusions about their phylogeographical relationship. Therefore, continuous surveillance of RVA, following the One Health principles, may provide relevant data for assessing the impact on the protectiveness of currently available vaccines.
Mammalian orthoreoviruses with reassortant genomes have recently been detected in various mammals and humans with respiratory, central nervous system, and gastrointestinal symptoms. This study ...describes the detection of the novel reassortant mammalian orthoreovirus SI-MRV07 in a traveler with gastroenteritis that returned from southeast Asia. The virus was initially detected with electron microscopy in stool, followed by propagation in the epithelial-like monkey kidney Marc145 cell line. Whole-genome sequencing revealed the reassortant nature of the genome segments, whereby the S1 genome segment was the most variable according to known sequences deposited in GenBank. Based on the nucleotide sequence of the S1 genome segment, the isolate clusters to serotype 2, close to the reference strain Jones T2J. The patient's serum showed the highest virus neutralization capacity toward SI-MRV07 and T2J isolates. This study provides additional insight into emerging mammalian orthoreoviruses with reassortant genomes and possible zoonotic potential, which should be carefully monitored in the future.
•Novel reassortant mammalian orthoreovirus isolate SI-MRV07 was characterized.•SI-MRV07 was identified in a patient stool by electron microscopy followed by culture.•Whole-genome sequencing revealed reassortant nature of the SI-MRV07 genome.•S1 genome segment shared 69.5% nucleotide identity with the most related T2J isolate.•Patient follow-up serum was highly reactive against SI-MRV07 and T2J isolates.
Bats are natural hosts of various coronaviruses (CoVs), including human CoVs, via an assumed direct zoonotic spillover or intermediate animal host. The present study aimed to investigate the ...circulation of CoVs in a bat colony in the Mediterranean region of Croatia. Guano and individual droppings from four bat species were sampled and tested with the E-gene sarbecovirus RT-qPCR, the pan-CoV semi-nested RT-PCR targeting the RdRp gene and NGS. Furthermore, bat blood samples were investigated for the presence of sarbecovirus-specific antibodies with the surrogate virus neutralization test (sVNT). The initial testing showed E-gene Sarebeco RT-qPCR reactivity in 26% of guano samples while the bat droppings tested negative. The application of RdRp semi-nested RT-PCR and NGS revealed the circulation of bat alpha- and betaCoVs. Phylogenetic analysis confirmed the clustering of betaCoV sequence with SARS-CoV-related bat sarbecoviruses and alpha-CoV sequences with representatives of the
subgenus. The results of sVNT show that 29% of bat sera originated from all four species that tested positive. Our results are the first evidence of the circulation of SARS-CoV-related coronaviruses in bats from Croatia.
