scholarly journals The means of combating persistent infection of viral diarrhea

2019 ◽  
Vol 49 (2) ◽  
pp. 49-56
Author(s):  
T. I. Glotova ◽  
A. A. Nikonova ◽  
S. V. Koteneva ◽  
A. G. Glotov

The paper presents results of research into the means of inhibiting persistent infection caused by noncytopathic biotype of bovine viral diarrhea virus. It was shown that bovine viral diarrhea virus, widespread in the cattle population in the whole world, can be a primary cause of pathology development of the respiratory and reproductive organs, and can cause a persistent form of infection in animals. The virus can contaminate fetal serum, cell cultures, trypsin, and other biological products, which leads to a decrease in the quality of biotech products from these materials and the spread of bovine viral diarrhea virus in a population of susceptible animals. The study was done on the model of a continuous calf coronary cell culture persistently infected with the noncytopathic biotype of the bovine viral diarrhea virus. The antiviral effect of two commercial preparations Ribavirin-Lipint and Reaferon-EC-Lipint was studied. The effectiveness of antiviral treatment of the infected cell culture was determined by the reverse transcription polymerase chain reaction, carried out in two versions: with electrophoresis and in real-time mode. It was found that these drugs in doses of 0.05 mg / ml and 30000 IU / ml, respectively, when added to growth medium for 24 consecutive passages, led to a decrease in the infectious activity of the bovine viral diarrhea virus in the cell culture, but did not cure it completely from the persistent infection caused by the noncytopathic biotype of the virus. Application of antiviral drugs is one of the ways to decrease economic losses caused by biological product contamination, the use of persistently infected animals for pedigree purposes and restrictions in international cattle trade.

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Erdachew Yitagesu ◽  
Wendi Jackson ◽  
Nigatu Kebede ◽  
Woutrina Smith ◽  
Tsegaw Fentie

Abstract Background Bovine Viral Diarrhea virus (BVDV) is one of important diseases of cattle worldwide causing economic losses to the cattle industry primarily due to increased premature culling and decreased reproductive performance. The virus can cross the placenta during early pregnancy and result in the birth of persistently infected (PI) calves that are efficient transmitters of BVDV and serving as the primary reservoirs for BVDV. Relatively few studies have focused on understanding BVDV seroprevalence, virus detection, genotyping and its distribution in Africa. Most BVDV research in Ethiopia has involved serologic surveys in adult cattle, rather than the identification of PI calves, despite their role in viral shedding and recurring infections. A cross-sectional study was undertaken in three different livestock production systems of Ethiopia with the objective to estimate the prevalence of bovine abortion, calf mortality, and BVDV persistently infected calves. Results Ear notch samples (882) collected from calves in 349 households were tested for BVDV antigen using antigen capture enzyme-linked immunosorbent assay (ACE). All samples tested were negative for BVDV antigen. The overall animal level crude abortion and calf mortality prevalence were 4.0% (95% CI: 2.9–5.2) and 9.2% (95% CI: 7.7–11.0) respectively. The lower BVDV PI prevalence may be due to a lower effective contact rate between cattle reared in small-scale extensive production systems in Ethiopia. Conclusions This is the first report of BVDV Ag test in Ethiopia and no PI was detected in calves in the study areas. Since BVDV is a disease of great economic importance, this study finding must be interpreted with care since absence of evidence is not evidence of absence and even a single BVDV infected animal can serve as source of infection and contribute to the persistent spread of the virus. Greater attention needs to be given to screening for PI animals through testing large number of animals and culling positive animals. Hence, future research should focus on regions and production systems with high BVDV seroprevalence followed by antigen ELISA or BVDV real-time PCR to detect persistently infected and acutely viremic animals.


2006 ◽  
Vol 87 (10) ◽  
pp. 2961-2970 ◽  
Author(s):  
Daisuke Yamane ◽  
Kentaro Kato ◽  
Yukinobu Tohya ◽  
Hiroomi Akashi

Bovine viral diarrhea virus (BVDV), which is classified in the genus Pestivirus, family Flaviviridae, can be divided into two biotypes according to its ability to induce a cytopathic effect in tissue culture cells. The mechanisms through which cytopathogenic (cp) BVDV induces cell death and non-cytopathogenic (ncp) BVDV causes persistent infection without producing cell death remain unclear. Here, it was found that the overexpression of four apoptosis-related cellular mRNAs in cells infected with cpBVDV could also be caused by synthetic dsRNA. In fact, it was found that the amount of dsRNA produced by cpBVDV considerably exceeded the amount yielded by ncpBVDV. To evaluate the possible involvement of dsRNA in the induction of apoptosis, this study examined whether RNAi-mediated depletion of two dsRNA-reactive cellular factors, dsRNA-dependent protein kinase and 2′,5′-oligoadenylate synthetase 1, resulted in the prevention of cpBVDV-induced apoptosis. Although the induction of apoptosis was reduced after the suppression of either factor alone, the simultaneous silencing of both factors resulted in an almost complete inhibition of apoptosis without affecting viral titre. These results showed that dsRNA is the main trigger of apoptosis in cpBVDV-infected cells and that the cytopathogenicity of BVDV depends on the yield potential of dsRNA. In contrast, ncpBVDV yielded minimal levels of dsRNA, thereby establishing a persistent infection without inducing apoptosis. This report supports the significance of viral dsRNA as a trigger of innate immune responses.


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