Identification of a pestivirus isolated from a free-ranging pudu (Pudu puda ) in Chile

High Exposure to Livestock Pathogens in Southern Pudu (Pudu puda) from Chile

A significant gap in exposure data for most livestock and zoonotic pathogens is common for several Latin America deer species. This study examined the seroprevalence against 13 pathogens in 164 wild and captive southern pudu from Chile between 2011 and 2023. Livestock and zoonotic pathogen antibodies were detected in 22 of 109 wild pudus (20.18%; 95% CI: 13.34-29.18) and 17 of 55 captive pudus (30.91%; 95% CI: 19.52-44.96), including five Leptospira interrogans serovars (15.38% and 10.71%), Toxoplasma gondii (8.57% and 37.50%), Chlamydia abortus (3.03% and 12.82%), Neospora caninum (0.00% and 9.52%), and Pestivirus (8.00% and 6.67%). Risk factors were detected for Leptospira spp., showing that fawn pudu have statistically significantly higher risk of positivity than adults. In the case of T. gondii, pudu living in "free-range" have a lower risk of being positive for this parasite. In under-human-care pudu, a Pestivirus outbreak is the most strongly suspected as the cause of abortions in a zoo in the past. This study presents the first evidence of Chlamydia abortus in wildlife in South America and exposure to T. gondii, L. interrogans, and N. caninum in wild ungulate species in Chile. High seroprevalence of livestock pathogens such as Pestivirus and Leptospira Hardjo in wild animals suggests a livestock transmission in Chilean template forest.

Molecular survey of selected viruses in Pudus (Pudu puda) in Chile revealing first identification of caprine herpesvirus-2 (CpHV-2) in South American ungulates

Viral diseases jeopardize the health of wildlife in Chile. However, this country lacks health surveillance programs that allow for defining preventive measures to tackle such diseases. The objective of this study was to determine the occurrence and the genetic diversity of pestivirus, herpesvirus and adenovirus in pudus from Chile. Blood samples from wild (n=34) and captive (n=32) pudus were collected between 2011 and 2019 and analyzed through consensus PCR. All the samples were negative to pestivirus and adenovirus. Herpesvirus was confirmed in four captive, and one wild pudu. All four zoo animals share the same sequence for both polymerase and glycoprotein genes. Both sequences share a 100% identity with caprine herpesvirus-2, classifying them in the same cluster as the Macavirus group. In turn, novel sequences of the polymerase and glycoprotein B genes were obtained from the wild pudu. Our study reports the first evidence of CpHV-2 infection in Chile and South American ungulate populations. Further research will be necessary to assess the pathogenicity of CpHV-2 in this species. It is also urgently recommended that molecular, serological and pathological screening should be conducted in Chilean wild and captive pudus to understand the impact of the herpesvirus on their populations.

Genetic diversity of Bovine Viral Diarrhea Virus from cattle in Chile between 2003 and 2007

BACKGROUND

Bovine Viral Diarrhea Virus causes significant economic losses in cattle. BVDV has high genomic diversity, with two species, BVDV-1 and BVDV-2, and at least twenty-one subgenotypes for BVDV-1 and four subgenotypes for BVDV-2. Vaccines are important tools to reduce the economic losses caused by this virus. However, vaccine strains must correspond to the antigenic profile of the viruses present in the region where the vaccine is applied. A restricted phylogenetic study with 14 viruses isolated from cattle between 1993 and 2001 showed that the genetic profile of BVDV in Chile consisted of viruses of both species and sub-genotypes 1a, 1b, 1c (currently 1j) and 2a. To determine more accurately the genetic profile of BVDV in Chile, in this study a larger number of viruses obtained from bovines between 2003 and 2007 were typed.

RESULTS

The study was performed using partial sequences from the 5' noncoding region (5'UTR) and E2 coding region of the viral genome of thirty-five Chilean viruses isolated from geographic regions that have 84.6% of the Chilean cattle. All tested viruses belonged to species BVDV-1. Eighteen viruses belonged to BVDV-1j subgenotype (51.4%), twelve belonged to BVDV-1b (34.3%) and five belonged to BVDV-1a (14.3%). The Chilean BVDV-1j viruses showed low genetic diversity, both among themselves and with the BVDV-1j present in other regions of the world. This could be explained by a relatively recent introduction of this viral subgenotype in cattle, which agrees with its low geographical distribution worldwide. Otherwise, Chilean BVDV-1b viruses grouped into a single cluster, different even than the viruses present in Argentina and Brazil, countries geographically close to Chile, a process of local evolution that could generate antigenic differences between the Chilean viruses and the viruses used as vaccine strains.

CONCLUSIONS

The high presence of viruses of the BVDV-1j subgenotype, which show major antigenic differences with BVDV-1a and BVDV-1b subgenotypes used in the commercial vaccines, suggest that BVDV-1j viruses could be an emergent subgenotype of BVDV in cattle in South America and suggest evaluating an update of the vaccines used in Chile.

Detection of persistent pestivirus infection in pudú (Pudu puda) in a captive population of artiodactyls in Chile

Background

Bovine Viral Diarrhea Virus (BVDV) is the viral agent causing the most important economic losses in livestock throughout the world. Infection of fetuses before their immunological maturity causes the birth of animals persistently infected with BVDV (PI), which are the main source of infection and maintenance of this pathogen in a herd. There is evidence of susceptibility to infection with BVDV in more than 50 species of the order Artiodactyla, and the ability to establish persistent infection in wild cervid species of South America could represent an important risk in control and eradication programs of BVDV in cattle, and a threat to conservation of these wild species. In this study, a serological and virological study was performed to detect BVDV infection in a captive population of non-bovine artiodactyl species in a Chilean zoo with antecedents of abortions whose pathology suggests an infectious etiology.

Results

Detection of neutralizing antibodies against BVDV was performed in 112 artiodactyl animals from a zoo in Chile. Three alpacas (Vicugna pacos), one guanaco (Lama guanicoe) and seven pudús (Pudu puda) resulted seropositive, and the only seronegative pudú was suspected to be persistently infected with BVDV. Then two blood samples nine months apart were analyzed by a viral neutralization test and RT-PCR. Non-cytopathogenic BVDVs were isolated in both samples. A phylogenetic analysis showed that the virus was highly related to BVDV-1b strains circulating among Chilean cattle.

Conclusions

This is the first report of a South American deer persistently infected with Bovine Viral Diarrhea Virus. Further studies are needed to determine the possible role of BVDV as a pathogen in pudús and as a threat to their conservation.

Detection of Mycobacterium avium subsp. paratuberculosis in a cattle/pudu interface

ABSTRACTMycobacterium avium subsp. paratuberculosis (Map) is the etiological agent of paratuberculosis. In Chile, information about Map isolation from both domestic ruminant and wildlife species has been accumulating, but it has to be extended to other species. The present study focuses specifically on one wild grazing species, the pudu (Pudu puda), one of the less known South American deer considered an endangered species that shares pastures with cattle in southern Chile, where the greatest part of the country's dairy cattle population is located. Convenient samples from 3 pudus were collected from one dairy farm where Map infection had previously been confirmed in cattle. All three pudus shed the bacterium in feces and the isolates are the same type of Map as described for cattle. This study represents the first case report of Map isolation in the pudu captured from the wild. It is also the first documented association between a Map-infected dairy herd and free-ranging wildlife species, such as pudu in the Los Ríos region, Chile. Since interspecies transmission of Map and other pathogens from livestock to pudu has already been demonstrated, the results from this study suggest that this free-ranging wildlife specie, inhabiting a dairy district in southern Chile, might represent another case of spillover host.

First report of malignant catarrhal fever in a captive pudu (Pudu puda)

A male, six-year-old pudu (Pudu puda) from an Italian zoo was submitted for postmortem examination after sudden death. Necroscopy revealed non-suppurative bronchopneumonia and degeneration of the liver and haemorrhagic lesions of the thymus, pericardium and spleen. Microscopically, multifocal perivascular mononuclear cell infiltrates were observed in the kidneys, lungs, spleen, and the portal triads of the liver. Histological examination of the brain showed meningitis, vasculitis and perivascular cuffs of mononuclear inflammatory cells. A region of the DNA polymerase gene of malignant catarrhal fever viruses was amplified by real-time PCR and nested PCR. PCR products from the tissue samples were sequenced and analysed. The sequences showed 99% similarity with a portion of the caprine herpesvirus 2 DNA polymerase gene. This is the first report of malignant catarrhal fever in a captive pudu.

Foot and mouth disease: a look from the wild side

We review the literature and discuss control options regarding foot and mouth disease (FMD) in wildlife around the world. There are more than 100 species of wild, feral, laboratory, or domesticated animals that have been infected naturally or experimentally with FMD virus. Apart from the African buffalo (Syncerus caffer) in sub-Saharan Africa, wildlife has not been demonstrated to play a significant role in the maintenance of FMD. More often, wildlife are passively infected when outbreaks of FMD occur in domestic livestock, and, in some wild ungulates, infection results in severe disease. Efforts to control FMD in wildlife may not be successful when the disease is endemic in livestock and may cause more harm to wildlife, human livelihoods, and domestic animals. Currently in sub-Saharan Africa, the complete eradication of FMD on a subcontinental scale in the near term is not possible, given the presence of FMD-infected African buffalo and the existence of weak veterinary infrastructures in some FMD-endemic countries. Therefore efforts to control the disease should be aimed at improved vaccines and improved use of vaccines, improved livestock management practices, and utilization of programs that can help in disease control such as the FMD Progressive Control Program and regulatory frameworks that facilitate trade such zonation, compartmentalization, and commodity-based trade. Though not meeting the definition of wildlife used in this review, feral domestic animals warrant a special concern with regard to FMD control.

Arcanobacterium pyogenes septicemia in a southern pudu (Pudu puda) following uterine prolapse

A 14-year-old female pudu (Pudu puda) developed a uterine prolapse after unassisted parturition. The length of time between the prolapse and replacement of the organ was not known but was less than 24 hr. When the prolapse was first noticed, uterine tissue appeared undamaged and was immediately cleaned with antiseptic solution, handled carefully during replacement, and prophylactic antibiotic and anti-inflammatory drugs were given. The pudu appeared clinically normal until 4 days postpartum, when she developed clinical signs of tenesmus, dysuria, and a purulent discharge from the vulva. Despite further treatment, the animal was found dead 10 days postpartum, even though it had not shown any other signs of systemic illness. Gross and histologic lesions supported a diagnosis of septicemia secondary to metritis. Arcanobacterium pyogenes was isolated from lung, liver, and uterine exudate.

Genetic and antigenic typing of border disease virus isolates in sheep from the Iberian Peninsula

A selection of 10 pestiviruses isolated from sheep from the Iberian Peninsula from 2001 to 2004 was characterised at the molecular level. The 5' untranslated region (5'-UTR) and N(pro)-coding gene were amplified by the reverse transcription-polymerase chain reaction (RT-PCR) and sequenced directly from purified products. All isolates were also typed antigenically with a panel of monoclonal antibodies (mAbs) raised against representative isolates of the four recognised pestivirus species. The genetic typing placed all the isolates in a new tentative type 4 of border disease virus (BDV), which was closely related to a pestivirus recently found in Pyrenean chamois (Rupicapra pyrenaica pyrenaica). Overall, the genotyping indicated a relatively wide diversity of the BDV type 4, which was best defined on the basis of N(pro) sequences. Antigenically, the isolates were recognised by two pan-pestivirus specific anti-NS3 mAbs, but only by some of the anti-glycoprotein specific mAbs raised against BDV, indicating partial antigenic overlap with other BDV isolates.

Vertical transmission of bovine viral diarrhoea virus (BVDV) in mousedeer (Tragulus javanicus) and spread to domestic cattle

This study investigates the transmission of bovine viral diarrhoea virus (BVDV) 1f from a persistently infected (PI) lesser Malayan mousedeer to two bovine calves. Different contact routes to two calves were analysed: 1) aerosol contact between two adjacent pens without physical contact; 2) indirect contact by use of common utensils; 3) direct nose-to-nose contact for 30 seconds. One of the calves was infected either by aerosol or indirect contact. The virus sequence in 247 nucleotides in the 5'-UTR was 100% identical in mousedeer and calf. To elucidate the distribution of BVDV within the affected mousedeer family the captive population in a Zoo was analysed. The maternal line of PI animals was maintained, whereas a PI male was able to reproduce and have a non-PI calf. As a consequence of this, six female PI mousedeer were killed; subsequent autopsies did not reveal any lesions. Sequencing mousedeer BVD virus in the E2 region (420 nucleotides) through 4 generations showed only 7 mutations, which were maintained from mother to offspring.

Pestiviruses in wild animals

Pestiviruses are not strictly host-species specific and can infect not only domestic but also wild animals. The most important pestivirus, CSFV, infects domestic pigs and wild boars, which may cause a major problem for successful CSFV eradication programmes. Mainly BVDV specific antibodies have been reported in captive and free-living animals. Virus has been isolated from some of these animal species, but since BVDV can contaminate cell cultures and foetal calf serum, early reports of BVDV isolation have to be considered with caution. Genetic typing of early pestivirus isolates from wild species revealed that the majority were BVDV-1. Of the pestiviruses identified so far three species (CSFV, BVDV-1, giraffe pestivirus) and three genotypes (BDV-2, BDV-4, pronghorn) appear to circulate in wildlife animal populations. The potential for pestiviruses to spread between farm animals and free-living animals is discussed as are epidemiological and technical problems, and the future direction of research.