The effect of vitamin and mineral supplements on the replication of coronaviruses in the SPEV cell culture

The article describes studies on the effect of vitamin and mineral supplements (VMS) on the replication of coronavirus in tissue culture. The cytopathic effect of the porcine transmissible gastroenteritis virus (strain TO36SD192 (Japan) and the vaccine strain "RIMS" was studied on the SPEV cell line in the presence of mineral and vitamin supplements (VMS) with an increased content of vitamins A and D. The results of the study showed that the introduction of vitamin and mineral supplements into the growth medium provides an increase in the yield of the RIMS virus by 16.7 - 23%. Interestingly, at the minimum infectious dose, the presence or absence of VMS does not in any way affect the titer of the virus of the reference strain of the coronavirus TO36SD192. However, an increase in the infectious dose by only one order of magnitude (1000 TDC50 / ml) stimulates an increase in the virus titer by 22.5% in the presence of VMS. With the addition of VMS, the RIMS strain reproduced more actively and the virus titer in the experiment with the addition of VMS was 30% higher than in the control (without VMS). A further increase in the infectious dose showed a significant increase in the virus titer from 13.4% to 6.25%. It should be noted that the TO36SD192 virus, well adapted to the SPEV culture, can be compared with viruses that cause seasonal ARVI in humans, which are also well adapted in the human body, and the use of VMS during the peak of the epidemic can stimulate viral replication. Since the RIMS strain virus is poorly adapted to the SPEV culture, its action can be compared with a virus that has entered the human population, for example, SARS-CoV-2. This means that taking vitamins at any infectious dose (during an epidemic) will stimulate the disease.

Detection and Genetic Diversity of Porcine Coronavirus Involved in Diarrhea Outbreaks in Spain

Porcine enteric coronaviruses include some of the most relevant viral pathogens to the swine industry such as porcine epidemic diarrhea virus (PEDV) or porcine transmissible gastroenteritis virus (TGEV) as well as several recently identified virus such as swine enteric coronavirus (SeCoV), porcine deltacoronavirus (PDCoV) or swine enteric alphacoronavirus (SeACoV). The aim of this study is the identification and characterization of enteric coronaviruses on Spanish pig farms between 2017 and 2019. The study was carried out on 106 swine farms with diarrhea outbreaks where a viral etiology was suspected by using two duplex RT-PCRs developed for the detection of porcine enteric coronaviruses. PEDV was the only coronavirus detected in our research (38.7% positive outbreaks, 41 out of 106) and neither TGEV, SeCoV, PDCoV nor SeACoV were detected in any of the samples. The complete S-gene of all the PEDV isolates recovered were obtained and compared to PEDV and SeCoV sequences available in GenBank. The phylogenetic tree showed that only PEDV of the INDEL 2 or G1b genogroup has circulated in Spain between 2017 and 2019. Three different variants were detected, the recombinant PEDV-SeCoV being the most widespread. These results show that PEDV is a relevant cause of enteric disorders in pigs in Spain while new emerging coronavirus have not been detected so far. However, the monitoring of these virus is advisable to curtail their emergence and spread.