Experimental infection of cattle, sheep and pigs with ‘Hobi’-like pestivirus

Abstract

To date, limited information is available on the ability of 'Hobi'-like pestiviruses (putative bovine viral diarrhoea 3) to infect and cause disease in animal species traditionally affected by pestiviruses. In order to obtain new insights into host range and pathogenic potential of this atypical pestivirus, BVDV-seronegative calves (n=5), lambs (n=5) and piglets (n=5) were experimentally infected with the European 'Hobi'-like strain Italy-1/10-1, whereas two animals per species served as uninfected controls. Appearance of clinical signs, leukopenia, viremia, viral shedding and seroconversion were monitored for 28 days post-infection. Calves and lambs were successfully infected, displaying respiratory signs (nasal discharge), moderate hyperthermia and leukopenia, viremia and viral shedding through the nasal and faecal routes. Antibody responses were observed in both animal species by ELISA and virus neutralisation assays. In contrast, inoculated piglets did not display any clinical signs nor leukopenia and viral RNA was not detected in any biological samples. Nevertheless, the presence of detectable antibodies by virus neutralisation accounted for a successful, albeit limited infection of these animals.

Clinical and virological characteristics of calves experimentally infected with a Brazilian isolate of bovine viral diarrhea virus type 1a

“…In subsequent bleeding, the titer increased until day 35 pi and then decreased by day 42 pi. Serological testing is an additional method to confirm infection, and the patterns observed here are similar to those observed in previous reports of acute BVDV infections (BRUM et al, 2002;DECARO et al, 2012). Serological cross reactivity with the standard Singer strain showed slightly lower titers.…”

“…It is possible that the absence of transmission was because the infected animals were excreting the virus at concentrations lower than that necessary for effective transmission. Such lack of transmission has been described in previous reports of experimental infection (DECARO et al, 2012;RIDPATH et al, 2013) and may be a characteristic of certain strains of this virus. This observation only serves to strengthen the importance of identifying and isolating infected animals in order to prevent the spread of infection (HOUE et al, 2006).…”

“…Previous reports showed that exposure to BVDV may cause a subclinical infection or several clinical manifestations in cattle (BOTTON et al, 1998;BIANCHI et al, 2011). Previously, experimental inoculation of calves with field isolates has been used as a method to examine infection parameters under controlled conditions (BRUM et al, 2002;DECARO et al, 2012;BAUERMANN et al, 2013;RIDPATH et al, 2013); such analyses enable the characterization of many aspects of infection, such as its acute phase and pathogenesis, host immune response, the transmission between animals, and the efficacy of vaccine protection and diagnostic testing (BRUM et al, 2002;BAUERMANN et al, 2013). Several studies have been conducted using this protocol and the results of these studies showed that virulence is highly variable among strains (BRUM et al, 2002;DECARO et al, 2012;RIDPATH et al, 2013).…”

“…Previously, experimental inoculation of calves with field isolates has been used as a method to examine infection parameters under controlled conditions (BRUM et al, 2002;DECARO et al, 2012;BAUERMANN et al, 2013;RIDPATH et al, 2013); such analyses enable the characterization of many aspects of infection, such as its acute phase and pathogenesis, host immune response, the transmission between animals, and the efficacy of vaccine protection and diagnostic testing (BRUM et al, 2002;BAUERMANN et al, 2013). Several studies have been conducted using this protocol and the results of these studies showed that virulence is highly variable among strains (BRUM et al, 2002;DECARO et al, 2012;RIDPATH et al, 2013). The 241.10 isolate used in the present study belongs to the BVDV-1a type, a subgenotype that is more prevalent in Brazilian herds (CORTEZ et al, 2006;BIANCHI et al, 2011;WEBER et al, 2014;SILVEIRA et al, 2015).…”

HoBi-like viruses

“…Seroconversion in calves and lambs peaked at DPI 21, with median titer of 512 and 64, respectively. 10 In a study using the Thai HoBi-like strain, 3-5-monthold calves were inoculated with Th04_Khonkaen or with a highly virulent BVDV strain. The disease observed in animals inoculated with the HoBi-like strain was milder than that produced by the highly virulent BVDV strain.…”