Identification and Epidemiology of a Rare HoBi-Like Pestivirus Strain in Bangladesh

Efficacy of H2O2 inactivated bovine virus diarrhoea virus (BVDV) type 1 vaccine in mice

BACKGROUND

Bovine viral diarrhea (BVD) is an acute febrile infectious disease caused by the bovine viral diarrhea virus (BVDV), which has brought huge economic losses to the world's cattle industry. At present, commercial inactivated BVDV vaccines may cause some adverse reactions during use. This study aims to develop a safer and more efficient inactivated BVDV vaccine.

METHODS

Here, we described the generation and preclinical efficacy of a hydrogen peroxide (H2O2) inactivated BVDV type 1 vaccine in mice, and administered it separately with commercial vaccine (formaldehyde inactivated) in mice to study its efficacy.

RESULTS

The BVDV type 1 IgG, IFN- γ, IL-4 and neutralizing antibody in the serum of the H2O2 inactivated vaccine group can be maintained in mice for 70 days. The IgG level reached its maximum value of 0.67 on the 42nd day, significantly higher than the commercial formaldehyde inactivated BVDV type 1 vaccine. IFN- γ and IL-4 reached their maximum values on the 28th day after immunization, at 123.16 pg/ml and 143.80 pg/ml, respectively, slightly higher than commercial vaccines, but the effect was not significant. At the same time the BVDV-1 neutralizing antibody titer reached a maximum of 12 Nu on the 42nd day post vaccination.

CONCLUSIONS

The H2O2 inactivated BVDV vaccine has good safety and immunogenicity, which provides a potential solution for the further development of an efficient and safe BVDV vaccine.

Abortion outbreak in pregnant goats and cows with coinfection of 'Candidatus Mycoplasma haemobos' and HoBi-like pestivirus

New emerging diseases, including 'Candidatus Mycoplasma haemobos' ('Ca. M. haemobos') and HoBi-like pestivirus in central China has been a huge challenge for ruminant production. From July to September 2022, an abortion outbreak affected 14 goat farms and 11 cattle farms in this area. To investigate whether the two pathogens are associated with the disease, samples were collected: Group 1 included 55 goat blood samples with foetal tissue samples and ticks on the skin; Group 2 included nine healthy goat blood samples; Group 3 included 36 cow blood samples with foetal tissue samples and ticks on the skin; and Group 4 included seven healthy cow blood samples. Then, these samples were analysed by serology, PCR, sequence analysis, and identification. A total of 339 Rhipicephalus (Boophilus) microplus and 61 Haemaphysalis longicornis ticks were identified in Group 1 and Group 3. By molecular detection, 32 'Ca. M. haemobos'-positive amplicons, and 27 HoBi-like pestivirus-positive amplicons were amplified from goats in Group 1; meanwhile, 20 'Ca. M. haemobos'-positive amplicons, and 18 HoBi-like pestivirus-positive amplicons were amplified from foetuses. Statistical significance (P = 0.002) and association (OR=7.556) between the 'Ca. M. haemobos' PCR results of foetus and goat samples were observed, and statistical significance (P = 0.017) and association (OR=4.271) between the HoBi-like pestivirus PCR results of foetus and goat samples were observed. These significances and associations were also observed in Group 3. In addition, coinfections were detected in Group 1 and Group 3. 'Ca. M. haemobos' was detected in both tick species. Further serological results revealed that the frequency of HoBi-like pestivirus was 20.0 % (11/55) in Group 1 % and 30.6 % (11/36) in Group 3 in central China. No ticks, pathogens, or neutralizing antibodies were observed in Group 2 or Group 4. This is the first molecular evidence of 'Ca. M. haemobos' and HoBi-like pestivirus natural coinfections in goats and cows with abortion in China. HoBi-like pestivirus and 'Ca. M. haemobos' can be transferred from goats/cows to their foetuses.

Whole-Genome-Sequence-Based Evolutionary Analyses of HoBi-like Pestiviruses Reveal Insights into Their Origin and Evolutionary History

HoBi-like pestivirus (HoBiPeV), classified under Pestivirus H species, is an emerging cattle pathogen of high economic impact. However, the origin and evolution of HoBiPeV are not very clear due to a lack of full genomic sequences from diverse clades. This study aimed to determine full-genome sequences of HoBiPeV strains of three novel clades (c, d and e) and perform full-genome-based genetic and evolutionary analyses. Bayesian phylogenetic analyses herein confirmed the existence and independent evolution of four main HoBiPeV clades (a, c, d and e) globally, with genetic divergence ranging from 13.0% to 18.2%. Our Bayesian molecular clock estimates revealed that HoBiPeV most likely originated in India, with a dated tMRCA of 1938 (1762–2000), evidencing a more recent origin of HoBiPeV. The evolution rate of HoBiPeV was estimated to be 2.133 × 10−3 subs/site/year at full-genome level but varied widely among individual genes. Selection pressure analyses identified most of the positively selected sites in E2. Additionally, 21.8% of the ORF codon sites were found under strong episodic diversifying selection, providing first evidence of negative selection in HoBiPeV evolution. No recombination event was evident for HoBiPeV-c, d and e strains. These findings provide new insights into HoBiPeV origin and evolutionary history for better understanding the epidemiology and host–pathogen interactions and stimulate vaccine research.

Human Exposure to Bats, Rodents and Monkeys in Bangladesh

Bats, rodents and monkeys are reservoirs for emerging zoonotic infections. We sought to describe the frequency of human exposure to these animals and the seasonal and geographic variation of these exposures in Bangladesh. During 2013-2016, we conducted a cross-sectional survey in a nationally representative sample of 10,002 households from 1001 randomly selected communities. We interviewed household members about exposures to bats, rodents and monkeys, including a key human-bat interface-raw date palm sap consumption. Respondents reported observing rodents (90%), bats (52%) and monkeys (2%) in or around their households, although fewer reported direct contact. The presence of monkeys around the household was reported more often in Sylhet division (7%) compared to other divisions. Households in Khulna (17%) and Rajshahi (13%) were more likely to report drinking date palm sap than in other divisions (1.5-5.6%). Date palm sap was mostly consumed during winter with higher frequencies in January (16%) and February (12%) than in other months (0-5.6%). There was a decreasing trend in drinking sap over the three years. Overall, we observed substantial geographic and seasonal patterns in human exposure to animals that could be sources of zoonotic disease. These findings could facilitate targeting emerging zoonoses surveillance, research and prevention efforts to areas and seasons with the highest levels of exposure.

Different impact of bovine complement regulatory protein 46 (CD46bov) as a cellular receptor for members of the species Pestivirus H and Pestivirus G

The genus Pestivirus within the family Flaviviridae comprises highly relevant animal pathogens such as bovine viral diarrhoea virus 1 and 2 (BVDV-1 and -2) classified into the two species Pestivirus A and Pestivirus B, respectively. First described in 2004, HoBi-like pestiviruses (HoBiPeV) represent emerging bovine pathogens that belong to a separate species (Pestivirus H), but share many similarities with BVDV-1 and -2. Additionally, two giraffe pestivirus (GPeV) strains both originating from Kenya represent another distinct species (Pestivirus G), whose members replicate very efficiently in bovine cells. In this study, we investigated the role of bovine complement regulatory protein 46 (CD46bov), the receptor of BVDV-1 and -2, in the entry of HoBiPeV and GPeV. For this purpose, bovine CD46-knockout and CD46-rescue cell lines were generated by CRISPR/Cas9 technology and subsequent trans-complementation, respectively. Our results provide strong evidence that the impact of CD46bov differs between viruses belonging to Pestivirus H and viruses representing Pestivirus G: CD46bov revealed to be a major cellular entry factor for HoBiPeV strain HaVi-20. In contrast, GPeV strain PG-2 presented as largely independent of CD46bov, suggesting a different entry mechanism involving other molecular determinants which remain to be identified. In addition, we demonstrated that, similar to BVDV-1 and -2, virus isolates of both Pestivirus H and Pestivirus G are able to adapt to cell culture conditions by using heparan sulfate to enter the host cell. In conclusion, our findings show that different bovine pestiviruses use diverse mechanisms of host cell entry.

Congenital Neurological Disease Associated With HoBi-like Pestivirus Infection in a Newborn Dairy Calf From Brazil

HoBi-like pestivirus (HoBiPeV) has been reported in several biological samples from cattle worldwide, but there are no descriptions of this virus associated with neurological symptoms. This report described the first occurrence of neurological disease associated with HoBiPeV in a newborn dairy calf. A mixed-breed Holstein calf had severe neurological symptoms at birth and died at 21 days old. The tissue fragments (central nervous system (CNS), myocardium, liver, kidney, lung, intestine, and spleen) were submitted to reverse transcription (RT)–PCR assay for the partial 5'-untranslated region (5'UTR) and N-terminal autoprotease (Npro) gene of the pestivirus genome, and the CNS tissue fragments were submitted to histopathological and immunohistochemical evaluation. The RT–PCR assay indicated that the kidney, CNS, and intestinal tissue fragments were positive for the pestivirus 5'UTR, and the CNS and intestinal tissue fragments were positive for the pestivirus Npro gene. Amplicons with high DNA quantification in the 5'UTR (CNS—cerebral cortex) and Npro (CNS—cerebral cortex and intestine) RT–PCR assays were sequenced. The nucleotide (nt) sequence and phylogenetic analysis of the 5'UTR strain exhibited 93.6 to 99.4%, 85%, 89.4 to 89.9%, 85.1%, and 90.5 to 91.5% nt identity with HoBiPeV strains from clades a, b, c, d, and e, respectively. The Npro amplicons showed 99.7% nt identity to each other and 90.4 to 96.5%, 85.1 to 85.3%, 79.2 to 79.7%, and 85.8 to 86.5% nt identity with HoBiPeV strains from clades a, c, d, and e, respectively. A histopathology revealed neuronal necrosis at the cerebrum, cerebellum, and brain stem. An immunohistochemical assay designed to identify antigens of bovine viral diarrhea virus revealed positive intracytoplasmic immunoreactivity within neurons at the cerebral cortex, cerebrum, cerebellum, and spinal cord. Thus, this report provides information about the first identification of HoBiPeV in tissues of the CNS in a newborn dairy calf with neurological symptoms.

First detection of emerging HoBi-like Pestivirus (BVD-3) among some persistently infected dairy cattle herds in Egypt

Bovine viral diarrhoea virus (BVDV) is a serious veterinary health concern worldwide. We conducted this study to determine the prevalence of persistent infections (PI) and identify the current strain among some dairy cattle herds in Egypt. A total of 240 serum samples were collected from six Egyptian provinces. Between 2019 and 2020, samples were tested by Enzyme linked immunosorbent assay (ELISA) for detection of PI animals, and then molecular characterization was performed. Six calves were found PI with a prevalence of 2.5% (6/240). Using molecular characterization, HoBi-like Pestivirus (BVD-3) was successfully identified in Egypt for the first time. Based on the BVD-3 reference strains on Genbank, the detected strains had an identity ranging from 98.8 to 99.6%. Partial nucleotide sequence of the 5'UTR gene for six tested samples was submitted to Genbank with accessions: OM324396, OM324397, OM324398, OM324399, OM3243100, and OM3243101.

Non-Bovine Species and the Risk to Effective Control of Bovine Viral Diarrhoea (BVD) in Cattle

Bovine viral diarrhoea virus (BVDV) is an economically important and highly prevalent virus of domestic cattle. Infections with BVDV may lead to both, reproductive and immunological effects that can result in widespread calf losses and increased susceptibility to diseases, such as mastitis and respiratory disease. While BVDV is generally considered to be host specific, it and other Pestivirus species, such as Border disease virus (BDV) in sheep, have been shown to be infecting species other than those from which they were originally isolated from. Recently BVDV was placed on the OIE’s list of notifiable disease and control and eradication programmes for BVDV have been developed throughout much of Europe, the United States, and the United Kingdom. While some countries, including Sweden and Ireland have successfully implemented eradication programmes, other countries such as New Zealand and Australia are still in the early stages of BVDV control. Despite effective control methods, incursions of BVDV into previously cleared herds still occur. While the cause of these incursions is often due to lapses in control methods, the ability of ruminant pestiviruses to infect species other than cattle poses the question as to whether non-bovine species could be impeding the success of BVDV eradication and control. As such, the aim of this review is to make mention of what is known about the cross-species transmission of BVDV, BDV and other pestiviruses between cattle and non-bovine ungulate species and draw conclusions as to the risk non-bovine species pose to the successful control and eradication of BVDV from cattle.

Epidemiology of Pestivirus H in Brazil and Its Control Implications

Along with viruses in the Pestivirus A (Bovine Viral Diarrhea Virus 1, BVDV1) and B species (Bovine Viral Diarrhea Virus 2, BVDV2), members of the Pestivirus H are mainly cattle pathogens. Viruses belonging to the Pestivirus H group are known as HoBi-like pestiviruses (HoBiPev). Genetic and antigenic characterization suggest that HoBiPev are the most divergent pestiviruses identified in cattle to date. The phylogenetic analysis of HoBiPev results in at least five subgroups (a–e). Under natural or experimental conditions, calves infected with HoBiPev strains typically display mild upper respiratory signs, including nasal discharge and cough. Although BVDV1 and BVDV2 are widely distributed and reported in many South American countries, reports of HoBiPev in South America are mostly restricted to Brazil. Despite the endemicity and high prevalence of HoBiPev in Brazil, only HoBiPev-a was identified to date in Brazil. Unquestionably, HoBiPev strains in BVDV vaccine formulations are required to help curb HoBiPev spread in endemic regions. The current situation in Brazil, where at this point only HoBiPev-a seems present, provides a more significant opportunity to control these viruses with the use of a vaccine with a single HoBiPev subtype. Despite the lack of differentiation among bovine pestiviruses by current BVDV tests, the reduced genetic variability of HoBiPev in Brazil may allow reliable identification of cases within the region. On the other hand, introducing foreign ruminants, biologicals, and genetic material to South America, especially if it originated from other HoBiPev-endemic countries, should consider the risk of introducing divergent HoBiPev subtypes.

Molecular characterization of recent HoBi-like pestivirus isolates from cattle showing mucosal disease-like signs in India reveals emergence of a novel genetic lineage

Natural infections with HoBi-like pestivirus (HoBiPeV) have been detected in cattle in South America, Europe and Asia with a range of clinical manifestations including fatal mucosal disease (MD). In India, although HoBiPeV in cattle has been reported, there is no information on currently circulating HoBiPeV strains and associated severe clinical disease. Between September 2018 and December 2019, suspected cases of bovine viral diarrhoea with severe disease in cattle were noticed in farmers' small holdings in Tamil Nadu State. To determine the extent of pestivirus infection, blood, serum, nasal or oral swab samples of 46 cattle from 18 villages were tested. Based on the real-time RT-PCR, antigen ELISA and nucleotide sequencing results, pestivirus was detected in nine cattle from eight villages in two districts and all pestiviruses were identified as HoBiPeV. All nine HoBiPeV-infected cattle displayed clinical signs resembling MD and HoBiPeV isolates (n = 9) obtained were characterized at genetic and antigenic level. Phylogenetic analyses based on 5'-untranslated regions (5'-UTR), N^pro and combined 5'-UTR-N^pro gene sequences revealed that eight HoBiPeV isolates clustered into a clade, distinct from all reported HoBiPeV clades (a-d), whereas one belonged to HoBiPeV-d clade, thus providing evidence of emergence of a novel HoBiPeV clade (e). This was also supported by HoBiPeV-e clade-specific amino acid substitutions in N^pro and the antigenic reactivity patterns. The study demonstrates the existence and independent evolution of five HoBiPeV clades (four main clades) globally and surprisingly three exclusive to India. Also we confirm first HoBiPeV occurrence in southern India with predominant prevalence of HoBiPeV-e strains. Besides demonstrating increased HoBiPeV genetic diversity, here we show association of HoBiPeV with severe clinical disease involving fatalities highlighting impact of HoBiPeV on cattle health. The emergence of a novel HoBiPeV lineage provides new insights on global HoBiPeV epidemiology and genetic diversity reiterating the need for continuous monitoring of HoBiPeV in India.

HoBi-Like Pestivirus and Reproductive Disorders

HoBi-like pestivirus (HoBiPeV) is an emerging group of pestiviruses that has been detected in cattle and other ruminants in South America, Europe, and Asia. Analogous to other bovine pestiviruses, namely bovine viral diarrhea (BVDV) 1 and 2, HoBiPeV is able to cause a variety of clinical forms that range from asymptomatic infections to fatal disease, having a great impact on cattle productions and causing substantial economic losses, mainly as a consequence of the occurrence of reproductive failures. The manuscript aims to provide an updated review of the currently available literature about the impact of HoBiPeV infection on cattle reproduction. The reproductive disorders observed in cattle due to natural and experimental infections caused by this virus are reported along with the few available in-vitro studies involving the reproductive tract. HoBiPeV should be considered among the bovine pathogens that impact on reproduction, but there is a need for more specific and sensitive diagnostic methods, while the cross-protection elicited by commercially available BVDV vaccines should be better investigated.

HoBi-like pestivirus infection leads to bovine death and severe respiratory disease in China

HoBi-like pestivirus is an emerging atypical pestivirus in cattle and small ruminants, causing clinical signs similar to those observed in bovine viral diarrhoea virus infections. Natural infection of HoBi-like pestivirus has been reported in cattle herds and small ruminants in multiple countries in South America, Europe and Asia. However, HoBi-like pestiviruses were only identified from contaminated bovine serum and small ruminants in China. So far, no clinical cases induced by HoBi-like pestivirus infection were reported in Chinese cattle herds. Here, for the first time, we reported natural infection of HoBi-like pestivirus in a cattle herd in China. Sick cattle with severe respiratory and diarrhoea and high fatality rate were found in a beef cattle herd in Shandong province in November 2017. RT-PCR, viral isolation, sequencing and phylogenetic analysis showed that the primary causative agent was HoBi-like pestivirus. The isolated HoBi-like pestivirus strain, SDJN-China-2019, shared 94.1%-97.5% homology with the LV168-20_16RN strain from Brazil in nucleotide of 5'UTR, N^pro and E2 while it shared only 88.5%-92.1% homology with Asian HoBi-like virus strain Th/04-Khonkaen. Multiple unique mutations of amino acid were observed in N^pro and E2 proteins of SDJN-China-2019, which were different from that of other reference strains. In summary, this study provides the first evidence of HoBi-like pestivirus infection in Chinese cattle herds, raising potential threat to the cattle industry in China.

HoBi-like pestivirus infection in an outbreak of bovine respiratory disease

HoBi-like is an emerging pestivirus of the family Flaviviridae detected in cattle herds and biological products of bovine origin in many parts of the world, causing disease similar to that observed in bovine viral diarrhea virus (BVDV) infections. In this study we reported the detection of HoBi-like pestivirus in an outbreak of respiratory disease in calves from Brazil, seropositive for viruses of the bovine respiratory disease complex (BRDC). Thus, serum samples and nasal swabs were collected from calves up to one year old, presenting or not clinical signs of respiratory disease. Serum samples were submitted to virus neutralization test (VNT) for BVDV-1, BVDV-2, bovine herpesvirus-1 (BoHV-1), bovine respiratory syncytial virus (BRSV) and bovine parainfluenza-3 (BPIV-3). These samples were also tested for the presence of pestiviruses (BVDV-1, BVDV-2 and HoBi-like) and BoHV-1 by RT-PCR and PCR, respectively. Nasal swabs were analyzed by RT-PCR for pestiviruses, BRSV and BPIV-3. VNT results showed high serological prevalence and a wide range of antibodies titers, for all viruses studied, in calves of different age groups. The RT-PCR amplified the 5'UTR and E2 regions of pestiviruses of four calves, from both nasal swabs and serum samples, which sequencing identified the HoBi-like pestivirus. This is the first detection of HoBi-like in nasal secretions of calves in an outbreak of respiratory disease in Brazil, along with the serological detection of other respiratory viruses. We concluded that HoBi-like pestivirus should be considered as part of the BRDC, as a differential diagnosis, to take correct measures of control and prophylaxis.

A genetic profile of bovine pestiviruses circulating in Brazil (1998-2018)

The pestiviruses bovine viral diarrhea virus 1 (BVDV-1), 2 (BVDV-2), and HoBi-like (HoBiPeV) are endemic among Brazilian cattle, the world's largest commercial bovine herd. In the last two decades (1998-2018) over 300 bovine pestiviruses have been partially or fully sequenced in Brazil, including viruses from different regions, different epidemiological backgrounds, and associated with diverse clinical presentations. Phylogenetic analysis of these viruses demonstrated a predominance of BVDV-1 (54.4%), with subgenotypes -1a (33.9% of total) and -1b (16.3%) being more frequent and subgenotypes -1d, -1e, and -1i at very low frequencies. The overall BVDV-2 frequency was 25.7% but it varied largely by region, reaching up to 48% in Southern states. BVDV-2b was the predominant subgenotype (84.8% of BVDV-2), followed by BVDV-2a (8.86%). HoBiPeV accounted for 19.9% (61/307) of the genotyped viruses and were detected at high frequency in cattle from Northeastern states. These findings demonstrate a unique mix of pestivirus species and subgenotypes, unlike that seen in Europe or North America. The design of effective diagnostic tools, vaccines, and control programs for limiting bovine pestivirus infections in Brazil must take into consideration this unique mix of viruses. This article provides a critical review of two decades of genetic identification of pestiviruses in Brazil.

Pathogen spread and globalization: The case of Pestivirus heterogeneity in southern Italy

Pestiviruses are responsible for widespread diseases affecting cattle, pigs and other ruminants, presenting a wide range of clinical manifestations, with significant impact on animal production. Given the recent various reports of a relatively high number of new strains and atypical genomic variants, in the present study, ninety-seven genomic sequences from southern Italy have been evaluated applying the palindromic nucleotide substitutions method, based on 5'-UTR secondary structure alignment and computing genetic distance among strains in the internal ribosome entry site. Sequence analysis revealed a highly heterogeneous virus population, indicating the introduction of virus variants of Bovine viral diarrhea virus and Border disease virus species from foreign countries. The application of different analytical procedures was useful to avoid interpretation difficulties. Circulation of heterogeneous virus populations showed the need for more accurate epidemiological investigations and stringent veterinary controls to protect animal health and welfare.

Increased genetic diversity of BVDV strains circulating in Eastern Anatolia, Turkey: first detection of BVDV-3 in Turkey

Bovine viral diarrhea virus (BVDV) is a pathogen associated with loss of meat, milk, and reproductive performance in cattle across the world. There have been two types of BVDV identified worldwide: BVDV-1 and BVDV-2. However, a new type of BVDV, named HoBi-like pestivirus (BVDV-3), has been identified recently. BVDV presence in Turkey has been reported since the 1990s, but a mandatory vaccination program has not been implemented in Turkey so far. In serological studies conducted in Turkey for BVDV, reported seropositivity has been 50% on average. The aim of this study is to determine the genetic diversity of BVDV in blood and abortion materials from bovine in eastern Turkey. The presence of the virus was determined by antigen ELISA test. As a result of the phylogenetic analysis of 5'UTR, Npro and E2 genomic regions of the BVDV (n = 28), BVDV-1 (n = 25) was identified as the dominant type. In addition, BVDV-2 (n = 2) and BVDV-3 (n = 1) were determined which is the first report of HoBi-like pestivirus in Turkey. Although BVDV-1l (n = 19) was detected as the predominant sub-type of BVDV-1, 1a (n = 2), 1b (n = 1), 1c (n = 1), and 1d (n = 2) were also identified. In 2 samples, the BVDV-2 type detected was the 2a sub-type. In this study, it is emphasized that BVDV can be present in the abort materials as an agent and that it should be examined in the herd screening. In addition, it is understood that molecular epidemiological studies should continue for determining the genetic diversity of the viruses and that such studies should be carried out on the country basis. Necessary diagnostic programs should be developed for animals, which are imported or buying from other barns, and protection and control measures should be taken. The increase of reports on BVDV heterogeneity in Turkey and worldwide gets up related to the occurrence and spread of new BVDV types or variants, with potential implications for animal health and disease control.

Genetic identification of pestiviruses from beef cattle in Southern Brazil

Bovine pestiviruses, e.g., bovine viral diarrhea virus types 1 (BVDV-1 or Pestivirus A), BVDV-2 (Pestivirus B), and HoBi-like pestiviruses (HoBiPeV or Pestivirus H), have been shown to circulate in Brazilian cattle in varied proportions. In this study, we identified genetically pestiviruses circulating in beef cattle in Rio Grande do Sul, the southern most Brazilian state. Screening of serum of 15.584 beef calves destined to be export by an antigen capture ELISA and, subsequently, by reverse-transcription polymerase chain reaction (RT-PCR), revealed 135 containing pestivirus RNA. Genetic typing of these viruses based on nucleotide sequencing and phylogenetic analysis of the 5' untranslated region (5' UTR) of the viral genome allowed for the identification of 90 different viruses, being 38 BVDV-1 (42.2%), 31 BVDV-2 (34.4%), and 21 HoBiPeV (23.4%). Among BVDV-1, only subtypes BVDV-1a (n = 28, 31.1%) and BVDV-1b (n = 10, 11.1%) were identified. All 31 BVDV-2 isolates belonged to BVDV-2b subtype and the 21 HoBiPeV viruses clustered to subgroup 3a. Thus, this study provides an approximate genetic profile of pestiviruses circulating in beef cattle in a traditional Brazilian beef cattle-raising state.

High prevalence of persistently infected animals from bovine viral diarrhea in Colombian cattle

Background

Bovine Viral Diarrhea Virus (BVDV) is associated with gastrointestinal, respiratory and reproductive diseases of livestock across the world that causes continuous economic losses in the cattle industry. This virus can establish a persistent infection (PI) in calves after the fetal infection, making BVDV positive catle carriers and primary reservoirs which will constantly transmit the virus to healthy and new-born animals. For this reason, the detection of the PI animals in herds is the first line of prevention of the viral infection.

Results

In this study, PI animals were detected in five different regions of Colombia through RT-PCR techniques and confirmed by sequencing. BVDV genotypes were determined using one fragment of the 5’UTR. It was found a 7% BVDV prevalence in animals and 22% in farms; and genotype 1 was identified as a single genotype for all of the samples. All samples were BVDV 1a.

Conclusion

This is the first report in Colombia with higher prevalence rates compared with other places in the world, turned out to be of great importance for the ranchers, the vaccine producers and animal health control parties.

PHYLOGENETIC ANALYSIS OF BOVINE PESTIVIRUSES DETECTED IN SIBERIA

The results of phylogenetic analysis of three species of bovine pestiviruses circulating in six regions of Siberia, as well as those detected in fetal embryonic serum (FBS) and continuous cell cultures, are presented. The typing was made based on comparison of sequences from the 5' untranslated region (5'-UTR) of the viral genome. Among the highly productive dairy cattle, circulation of five subtypes of the BVDV1 (a, b, d, f, r) and BVDV2 was established. The predominant subtype was 1b (48% positive samples). The number of subtypes of BVDV1 was as follows: BVDV1: 1а (8%), 1b (48%), 1d (8%), 1f (16%) и 1r (8%) and BVDV2 (12%). Cell cultures revealed BVDV1a. The distribution of types and subtypes of viruses had geographical differences. BVDV1b, BVDV1d, BVDV1f и BVDV1r were detected in cattle or persistently infected (PI) animals in farms with respiratory distress. BVDV 1a revealed in the serum of PI heifer without manifestation of clinical symptoms. BVDV2 were detected in cattle with pathology of reproduction. The presence of the BVDV3 (atypical pestivirus) of the Italian group was established in seven lots of FBS obtained from two manufacturers. No evidence has been found for circulating of the atypical virus among cattle of various breeds, including imported, reindeers and red deers. Studies on the molecular epizootology of pestiviruses can be used to select and optimize the control strategy and address the issue of vaccine use in a particular region.

Respiratory signs, fever and lymphopenia in calves inoculated with Brazilian HoBi-like pestiviruses

Hobi-like viruses (HobiPeV) comprise a novel, recently classified species of bovine pestiviruses, originally identified in commercial fetal bovine serum of Brazilian origin and, subsequently, isolated from diseased animals in several countries. Although frequently isolated from clinical cases, most HobiPeV isolates failed to reproduce overt disease in cattle upon experimental inoculation. Herein, we describe the outcome of experimental infection of four to six months-old seronegative calves with two Brazilian HobiPeV isolates. Calves inoculated intranasally with isolate SV478/07 developed viremia between days 2 and 9 post-inoculation (pi) and shed virus in nasal secretions up to day 11pi. These animals presented hyperthermia (day 7 to 10-11 pi) and lymphopenia from days 4 to 8pi. Clinically, all four calves developed varied degrees of apathy, anorexia, mild to moderate respiratory signs (nasal secretion, hyperemia), ocular discharge and pasty diarrhea in the days following virus inoculation. In contrast, calves inoculated with isolate SV757/15 presented only hyperthermia (days 3 to 10-11 pi) and lymphopenia (days 4-8 pi), without other apparent clinical signs. In these animals, viremia was detected up to day 9 pi and virus shedding in nasal secretions lasted up to day 12-14 pi. Both groups seroconverted to the inoculated viruses, developing virus neutralizing (VN) titers from 320 to 5120 at day 28pi. These results extend previous findings that experimental infections of calves with HobiPeV are predominantly mild, yet they also indicate that field isolates may differ in their ability to cause disease in susceptible animals.

Mucosal disease-like lesions caused by HoBi-like pestivirus in Brazilian calves in 2010-2011: Clinical, pathological, immunohistochemical, and virological characterization

A HoBi-like pestivirus was first described in 2004 in a Brazilian fetal bovine serum that was exported to Germany. Nevertheless, it is believed that the virus had been present since the 1990's, when it was detected in buffalos of Brazilian origin. Reproductive and respiratory diseases have been reported since 2001 in cattle, and more recently, diseases accompanied by a clinical presentation of mucosal disease-like (MD-like lesions have been reported as well. In the present study, the authors reported the oldest case of MD--like in cattle, associated with a HoBi-like pestivirus infection. Diarrhea, anorexia, nasal discharge, hypersalivation, and weakness were observed in 20 calves. For two of the animals, clinical follow-ups were performed. Following their death, necropsy was performed on these two calves. The main gross alterations observed were ulcers and erosions in the upper and lower digestive tract and interdigital dermatitis. Clinical history, gross findings, histopathological examination, immunohistochemistry, RT-PCR, and virus isolation were determined as suitable tools for the diagnosis of a MD-like outbreak, caused by a HoBi-like pestivirus.

Seroprevalence of bovine viral diarrhea virus in crossbred dairy cattle in Bangladesh

AIM

The study was conducted to determine the seroprevalence of bovine viral diarrhea virus (BVDV) and hematological features in crossbred dairy cattle in Chittagong, Bangladesh.

MATERIALS AND METHODS

The antibody against BVDV in crossbred dairy cattle serum was detected by indirect enzyme-linked immunosorbent assay. The association of different categorical variables in the prevalence of BVDV has been studied. Blood samples were collected and analyzed to know the hematological variations in the study population.

RESULTS

The overall seroprevalence of BVDV in the study area was 51.1% (95% confidence interval [CI], 40.5-61.5). Among different physiological stages of animals, the highest 57.1% (95% CI, 42.2-71.2) prevalence was in case of non-pregnant animals. Aborted cows were found to be significantly (p<0.05) more seropositive 77.8% (95% CI, 52.4-93.6) than the non-aborted cows (77.8%, 95% CI, 52.4-93.6, compared to 44.7%, 95% CI, 33.3-56.6, respectively). Cows having the history of retained placenta were found more positive than without the history of retained placenta (63.2%, 95% CI, 38.4-83.7, compared to 54.7%, 95% CI, 40.4-68.4, respectively). Among the animals of different age groups, BVDV seroprevalence was higher 61.3% (95% CI, 42.2-78.2) in animals of more than 3 years up to 5 years, whereas 32% was in case of 0-1-year-old. Significant variation found in different geographical areas of the study area. Hematological analyses have shown variation between the BVDV positive and negative animals.

CONCLUSION

Seroprevalence of BVDV found to be high in the study area is also economically important and cause significant damage to the production industry. Therefore, it is necessary to conduct effective control measures to reduce the burden of BVDV.

Antigenic diversity of Brazilian isolates of HoBi-like pestiviruses

Hobi-like viruses comprise an unclassified group of bovine pestiviruses related to bovine viral diarrhea virus 1 (BVDV-1) and 2 (BVDV-2). These viruses were originally identified in fetal bovine serum from Brazilian origin and, subsequently, isolated from diseased animals in several countries. Herein we performed an antigenic characterization of eight Brazilian HoBi-like viruses isolated from persistently infected (PI) animals and from gastroenteric disease (2007-2015). Phylogenetic analysis based on the 5' unstranslated region (UTR) clustered these viruses with other HoBi-like viruses from European and Asiatic origin. Monoclonal antibody (MAb) binding indicated variability in the Hobi-like virus glycoprotein E2 and significant differences from the homologous BVDV-1 and BVDV-2 glycoprotein. Analysis of antigenic relatedness based on virus-neutralizing titers using virus-specific antisera revealed that HoBi-like viruses are antigenically very different from BVDV-1 and, to a lesser extent, from BVDV-2. Cross-neutralizing assays between pairs of HoBi-like viruses and their respective antisera indicated the existence of antigenic variability among these viruses, even for viruses isolated from the same herd in different occasions. Moreover, the identification of a HoBi-like isolate with low antigenic similarity with the other isolates indicates the potential existence of antigenic subgroups among HoBi-like virus isolates. Finally, sera of lambs immunized with commercial BVDV vaccines showed low or undetectable neutralizing activity against HoBi-like isolates. These results indicate significant antigenic differences between BVDV genotypes and Brazilian HoBi-like viruses and the existence of antigenic variability within this atypical group of pestiviruses. These findings extend the knowledge about the antigenic diversity of HoBi-like viruses and reinforce the need for their inclusion in current BVDV vaccines.

A newly developed BVDV-1 RT-qPCR Taqman assay based on Italian isolates: evaluation as a diagnostic tool

A single-step TaqMan® RT-qPCR was developed for the detection of bovine viral diarrhea virus type 1 (BVDV-1), an important pathogen of cattle worldwide. The assay was based on conserved 5'UTR sequences of Italian BVDV-1 isolates. In order to establish a diagnostic protocol which simplifies sample collection and processing, the assay was tested on a variety of biological specimens collected from persistently infected calves. The samples analyzed included PBMCs, plasma, dry blood, ear notch and hair bulb. Time and costs required for the analysis of each type of specimen were compared. The RT-qPCR, whose lower limit of detection was 100 copies of viral RNA (1 TCID50), correctly identified all PI animals, irrespective of the type of specimen. The highest copy numbers were obtained from the RNAs extracted from PBMCs, ear notches and hair bulbs. Hair bulb-supernatants directly used as a template allowed identification of all PI animals. In conclusion, based on time and cost evaluation, the most effective and efficient protocol was the one based on the direct analysis of hair bulb-supernatants, avoiding the RNA extraction step.

New Leaves in the Growing Tree of Pestiviruses

Pestiviruses are a group of viruses of veterinary importance infecting livestock animals like pigs, cattle, and sheep, and also wildlife animals like wild boar and different deer species. While for decades only four classical species (Classical swine fever virus, Bovine viral diarrhea virus types 1 and 2, Border disease virus), and a few so-called atypical pestiviruses were known (e.g., Giraffe virus, Pronghorn virus, HoBi virus), a series of novel pestiviruses was identified in the last years (Bungowannah virus, Bat pestivirus, Norway rat pestivirus, Atypical porcine pestivirus, LINDA virus). The Australian Bungowannah virus could be isolated and further characterized by classical sequencing, but all the other latest novel pestiviruses were identified by metagenomics using next-generation sequencing technologies. Here, we describe these new viruses and their discovery and characterization. Differentiation is made between the occurrence of classical pestiviruses in new species and novel viruses or virus types.

Identification of Natural Infections in Sheep/Goats with HoBi-like Pestiviruses in China

The natural infections of HoBi-like pestiviruses in cattle have been reported in South America, Europe and Asia. In China, although the detections of HoBi-like pestivirus have been reported, the epidemiological investigation was limited. From January 2014 to October 2015, several flocks of sheep/goats in Henan province in central China suffered respiratory diseases which were recovered slowly after antibiotics treatment. To test whether it is the HoBi-like pestivirus caused this symptom, 49 serum samples and 22 nasal swabs were then collected for analysis by serology and RT-PCR. Serological result revealed that prevalence of pestivirus in small ruminants was 12.2% (6/49) in central China. Sequence analysis of partial 5'-UTR nucleotides of pestivirus-positive samples suggested that HoBi-like pestivirus might have circulated in sheep/goats of China for a period and have evolved into new genotype clusters. It is apparent that the study provides the molecular evidence of natural infections in goat/sheep species with HoBi-like pestiviruses in China.

HoBi-Like Pestivirus and Its Impact on Cattle Productivity

The clinical features and economic impact of the infection caused by an emerging group of pestiviruses, namely HoBi-like pestivirus, in a cattle herd of southern Italy are reported. In 2011, the virus was first associated with respiratory disease, causing an abortion storm after 1 year and apparently disappearing for the following 3 years after persistently infected calves were slaughtered. However, in 2014, reproductive failures and acute gastroenteritis were observed in the same herd, leading to a marked decrease of productivity. A HoBi-like strain closely related to that responsible for previous outbreaks was detected in several animals. Application of an intensive eradication programme, based on the detection and slaughtering of HoBi-like pestivirus persistently infected animals, resulted in a marked improvement of the productive performances.

Efficiency of the Clinical Veterinary Diagnostic Practices and Drug Choices for Infectious Diseases in Livestock in Bangladesh

As in most low-income countries, adequate laboratory facilities are not available in Bangladesh to assist veterinarians in diagnosing animal diseases. We aimed to determine the efficiency of veterinary diagnoses for two common ruminant diseases in Bangladesh: Peste des petits ruminants (PPR) and foot-and-mouth disease (FMD). We conducted the study from May 2009 to August 2010 in three government veterinary hospitals where veterinarians collected samples from sick livestock and recorded the presumptive diagnosis on the basis of clinical presentations. Samples were tested for PPR and FMD using real-time RT-PCR. We estimated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the presumptive diagnoses when compared to laboratory tests. We tested 539 goats for PPR and 340 cattle and goats for FMD. Our results indicate that the veterinarians' presumptive diagnoses were different from laboratory findings for both PPR (P < 0.05) and FMD (P < 0.05). The overall sensitivity of the presumptive clinical diagnoses was 54% (95% CI: 47-61%) while specificity was 81% (95% CI: 78-84%) compared to real-time RT-PCR tests. The kappa value obtained in our validation process for PPR (kappa: 0.25) and FMD (kappa 0.36) indicated a poor performance of the presumptive diagnoses. Most of the animals (93%) were treated with antibiotics. Our findings indicate that veterinarians can detect animals not infected with FMD or PPR but miss the true cases. The clinical competency of these veterinarians needs to be improved and access to laboratory diagnostic facilities could help veterinarians to improve the diagnostics and outcomes. The rational use of antibiotics by veterinarians in animals must be ensured.

Comparison of 'HoBi'-like viral populations among persistent infected calves generated under experimental conditions and to inoculum virus

Like other members from the Pestivirus genus, 'HoBi'-like pestiviruses cause economic losses for cattle producers due to both acute and persistent infections. The present study analyzed for the first time PI animals derived from a controlled infection with two different 'HoBi'-like strains where the animals were maintained under conditions where superinfection by other pestiviruses could be excluded. The sequence of the region coding for viral glycoproteins E1/E2 of variants within the swarms of viruses present in the PI calves and two viral inoculums used to generate them were compared. Differences in genetic composition of the viral swarms were observed suggesting that host factors can play a role in genetic variations among PIs. Moreover, PIs generated with the same inoculum showed amino acid substitutions in similar sites of the polyprotein, even in serum from PIs with different quasispecies composition, reinforcing that some specific sites in E2 are important for host adaptation.

The two sides of border disease in Pyrenean chamois (Rupicapra pyrenaica): silent persistence and population collapse

In 2001, border disease virus (BDV) was identified as the cause of a previously unreported disease in Pyrenean chamois (Rupicapra pyrenaica) in Spain. Since then, the disease has caused a dramatic decrease, and in some cases collapse, of chamois populations and has expanded to nearly the entire distribution area in the Pyrenees. Chamois BDV was characterized as BDV-4 genotype and experimental studies confirmed that it was the primary agent of the disease. The infection has become endemic in the Central and Eastern Pyrenees. However, while most Pyrenean chamois populations have been severely affected by the disease, others have not, despite the circulation of BDV in apparently healthy individuals, suggesting the existence of different viral strategies for persisting in the host population. Changes in the interplay of pathogen, host and environmental factors may lead to the formation of different disease patterns. A key factor influencing disease emergence may be pathogen invasiveness through viral mutation. Host factors, such as behavior, immunity at the population level and genetic variability, may also have driven different epidemiological scenarios. Climatic and other ecological factors may have favored secondary infections, such as pneumonia, that under particular circumstances have been major contributing factors in the high mortality observed in some areas.

Multiplex real-time RT-PCR assay for bovine viral diarrhea virus type 1, type 2 and HoBi-like pestivirus

HoBi-like pestiviruses are emerging pestiviruses that infect cattle causing clinical forms overlapping to those induced by bovine viral diarrhea virus (BVDV) 1 and 2. As a consequence of their widespread distribution reported in recent years, molecular tools for rapid discrimination among pestiviruses infecting cattle are needed. The aim of the present study was to develop a multiplex real-time RT-PCR assay, based on the TaqMan technology, for the rapid and unambiguous characterisation of all bovine pestiviruses, including the emerging HoBi-like strains. The assay was found to be sensitive, specific and repeatable, ensuring detection of as few as 10(0)-10(1) viral RNA copies. No cross-reactions between different pestiviral species were observed even in samples artificially contaminated with more than one pestivirus. Analysis of field samples tested positive for BVDV-1, BVDV-2 or HoBi-like virus by a nested PCR protocol revealed that the developed TaqMan assay had equal or higher sensitivity and was able to discriminate correctly the viral species in all tested samples, whereas a real-time RT-PCR assay previously developed for HoBi-like pestivirus detection showed cross-reactivity with few high-titre BVDV-2 samples.

Development of a TaqMan assay for sensitive detection of all pestiviruses infecting cattle, including the emerging HoBi-like strains

A real-time RT-PCR assay based on the TaqMan technology was developed for rapid and sensitive detection of pestiviruses infecting cattle, i.e., bovine viral diarrhea virus (BVDV) 1, BVDV-2, and the emerging HoBi-like pestiviruses. The assay was linear and reproducible, being able to detect as few as 10 copies of viral RNA. By real-time RT-PCR analysis of 986 biological samples collected from cattle herd with clinical signs suggestive of pestivirus infection and from animals recruited in a pestivirus surveillance programme, 165 pestivirus positive samples were detected, including 6 specimens, 2 nasal swabs, and 4 EDTA-blood samples, that tested negative by a gel-based RT-PCR assay targeting the 5'UTR. The developed TaqMan assay represents a new reliable and effective tool for rapid and sensitive diagnosis of infections caused by all pestiviruses circulating in cattle, thus being useful for extensive surveillance programs in geographic areas where HoBi-like pestiviruses are co-circulating with BVDV-1 and BVDV-2.

HoBi-like viruses – the typical ‘atypical bovine pestivirus’

HoBi-like viruses, also referred to as bovine viral diarrhea virus 3 (BVDV-3) and atypical pestivirus, have been proposed as a new putative bovine pestivirus species. These viruses were first identified in the last decade and are currently distributed in at least three continents. Published findings suggest that these viruses may be endemic at least in parts of South America and Asia. The clinical presentations in cattle, described in field outbreaks and controlled studies, are similar to those associated with BVDV and range from subclinical to mild clinical signs, sporadically associated with reproductive losses, respiratory illness and hemorrhagic syndrome. The complete host range of HoBi-like virus is unknown, but data suggest higher adaptation of HoBi-like viruses to ruminants than swine. Acute infections, characterized by mild clinical signs, such as low-grade pyrexia and leukopenia, have been observed in both cattle and sheep. Virus has been isolated from nasal swabs indicating that virus was being shed. While seroconversion has been observed in pigs, no clinical presentation or viral shedding was evident following inoculation. While some commercial BVDV diagnostic tests may detect HoBi-like viruses, these tests do not differentiate between BVDV and HoBi-like viruses. The differentiation of BVDV and HoBi-like viruses is critical to the design of surveillance programs for these viruses.

Serological Evidence of Coxiella burnetii Infection in Cattle and Goats in Bangladesh

We tested 1149 ruminant sera conveniently collected from three districts of Bangladesh to identify the serological evidence of Coxiella burnetii infection in cattle and goats by enzyme-linked immunosorbent assay. We found that 0.7% (8/1149) of ruminants had detectable immunoglobulin G for C. burnetii: 0.65% (4/620) in cattle and 0.76% (4/529) in goats. A sub-set of ruminant samples was retested and confirmed by immunofluorescence assay (18/112). Although we cannot rule out false-positive reactions, our study suggests the presence of C. burnetii in cattle and goats in Bangladesh. Further studies are required to estimate disease burden at the population level and identify risk factors for Q fever in ruminants in Bangladesh.

HoBi-like pestivirus experimental infection in pregnant ewes: Reproductive disorders and generation of persistently infected lambs

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HoBi-like pestivirus was administered to pregnant sheep.

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Infected animals displayed reproductive disorders.

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Persistently infected lambs were born that shed the virus through all body fluids.

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Sheep may serve as an alternative model for HoBi-like pestivirus vaccine studies.

In order to evaluate sheep as experimental model to test the efficacy of HoBi-like pestivirus vaccines for cattle, 10 sheep at different stages of pregnancy (30 or 50 days) were experimentally infected with the Italian prototype isolate Italy-1/10-1. Irrespective of the stage of pregnancy, virus inoculation resulted in reproductive failures, consisting of abortion, stillbirths or birth of weak or persistently infected (PI) lambs. Aborted fetuses, stillborn and dead lambs displayed extensive histopathological changes, consisting of hemorrhages, congestion and mononuclear infiltration in major organs. Pestiviral antigens were detected by immunohistochemistry in most tissues with remarkable signals in lungs and kidneys. PI lambs were constantly viremic, shed the virus through the nasal secretions and feces and, in all cases but one, did not have detectable HoBi-like pestivirus antibodies before the assumption of colostrum. The single seropositive infected lamb showed low-titer viremia and viral shedding that ceased only several weeks after the 3-month observation period. The study proves that sheep are susceptible to the reproduction failures caused by HoBi-like pestivirus infection and can serve as a suitable model for the evaluation of the fetal protection induced by homologous experimental vaccines.

Generation of calves persistently infected with HoBi-like pestivirus and comparison of methods for detection of these persistent infections

The identification and elimination of persistently infected (PI) cattle are the most effective measures for controlling bovine pestiviruses, including bovine viral diarrhea virus (BVDV) and the emerging HoBi-like viruses. Here, colostrum-deprived calves persistently infected with HoBi-like pestivirus (HoBi-like PI calves) were generated and sampled (serum, buffy coat, and ear notches) on the day of birth (DOB) and weekly for 5 consecutive weeks. The samples were subjected to diagnostic tests for BVDV--two reverse transcriptase PCR (RT-PCR) assays, two commercial real-time RT quantitative PCR (RT-qPCR), two antigen capture enzyme-linked immunosorbent assays (ACE), and immunohistochemistry (IHC)--and to HoBi-like virus-specific RT-PCR and RT-qPCR assays. The rate of false negatives varied among the calves. The HoBi-like virus-specific RT-PCR detected HoBi-like virus in 83%, 75%, and 87% of the serum, buffy coat, and ear notch samples, respectively, while the HoBi-like RT-qPCR detected the virus in 83%, 96%, and 62%, respectively. In comparison, the BVDV RT-PCR test had a higher rate of false negatives in all tissue types, especially for the ear notch samples (missing detection in at least 68% of the samples). The commercial BVDV RT-qPCRs and IHC detected 100% of the ear notch samples as positive. While ACE based on the BVDV glycoprotein E(rns) detected infection in at least 87% of ear notches, no infections were detected using NS3-based ACE. The BVDV RT-qPCR, ACE, and IHC yielded higher levels of detection than the HoBi-like virus-specific assays, although the lack of differentiation between BVDV and HoBi-like viruses would make these tests of limited use for the control and/or surveillance of persistent HoBi-like virus infection. An improvement in HoBi-like virus tests is required before a reliable HoBi-like PI surveillance program can be designed.