Causes of fetal death in the Flemish cattle herd in Brazil.

Background and Aim: Flemish cattle in Brazil are on the brink of extinction and are found only in one herd in Lages, Santa Catarina State. This study aimed to uncover the reasons for the recurring abortions in the Flemish cattle herd. Materials and Methods: Seventeen Flemish fetuses underwent postmortem examinations, with samples collected for histopathology and microbiology culture tests, polymerase chain reaction (PCR) test for Neospora caninum, and reverse transcription-PCR (RT-PCR) test for bovine viral diarrhea virus (BVDV) from 2015 to 2020. Results: Of the 17 fetuses, N. caninum was the most common diagnosis and was found in 88% (15/17). One fetus (5.8%) had a coinfection with N. caninum and Citrobacter amalonaticus, leading to fibrinonecrotic pericarditis. All fetuses tested negative for BVDV by RT-PCR. Of the 107 dams tested by indirect immunofluorescence assay, 26 (25.2%) were anti-N. caninum seropositive, with 17 (65.4%) aborting and 5 (19.2%) having estrus repetition. Reverse transcription-PCR results showed that 9 (8.4%) of the serum samples collected from dams tested positive, which tested follow-up test 3 months later, indicating a BVDV transient infection. The factors that contributed to neosporosis included dogs' access to pastures and improper disposal of fetal remains, which made it easier for dogs to consume them. Conclusion: This study warns the occurrence of N. caninum as a cause of reproductive disorders that can lead to abortion in the studied Flemish cattle herd.

Microcephaly and hydrocephalus in a sheep fetus infected with Neospora caninum in Southern Brazil - Short communication.

A case of non-communicating hydrocephalus and microcephaly in a sheep fetus infected with Neospora caninum from Lages, Santa Catarina, Brazil, is reported. Macroscopically, there was moderate flattening and narrowing of the skull, and the portion of the cerebral hemispheres was markedly reduced in size, measuring 3.5 × 3.5 × 0.5 cm, with marked diffuse flattening of the brain gyri and dilation of the lateral ventricles. Cerebrospinal fluid samples were positive to N. caninum detection by PCR. Histologically, there was discrete focal lymphoplasmacytic necrotising encephalitis on the floor of the lateral ventricle, discrete multifocal gliosis and discrete multifocal lymphoplasmacytic myositis. Through the molecular detection of N. caninum in the cerebrospinal fluid, it was possible to report what appears to be the first case of non-communicating hydrocephalus and microcephaly in an ovine fetus infected with N. caninum.

Temporal analysis of bovine pestivirus diversity in Brazil.

In this study, phylogenetic and evolutionary analyses of cattle pestiviruses (BVDV-1, 2 and HoBiPeV) originating in Brazil were used to investigate the temporal diversification of subgenotypes in the country. Inferred dated phylogeny and time of the most recent common ancestor (tMRCA) demonstrated that some BVDV subgenotypes (1a, 1b, 1d, 1e, and 2b) and HoBi-like sequences clustered according to the region in which they were collected and that the diversification of subgenotypes appears to have occurred around the introduction of first Bos taurus and then Bos indicus, followed by expansion to form the adapted Brazilian breeds. The present results help to elucidate the temporal facts that led to diversification of ruminant pestiviruses in cattle in Brazil.

Detection of coronavirus in vampire bats (Desmodus rotundus) in southern Brazil.

The vampire bat (Desmodus rotundus) is a haematophagous animal that feeds exclusively on the blood of domestic mammals. Vampire bat feeding habits enable their contact with mammalian hosts and may enhance zoonotic spillover. Moreover, they may carry several pathogenic organisms, including coronaviruses (CoVs), for which they are important hosts. The human pathogens that cause severe acute respiratory syndrome (SARS-CoV), Middle East respiratory syndrome (MERS-CoV) and possibly coronavirus disease 2019 (SARS-CoV-2) all originated in bats but required bridge hosts to spread into human populations. To monitor the presence of potential zoonotic viruses in bats, the present work evaluated the presence of CoVs in vampire bats from southern Brazil. A total of 101 vampire bats were captured and euthanized between 2017 and 2019 in Rio Grande do Sul state, southern Brazil. The brain, heart, liver, lungs, kidneys and intestines were collected and macerated individually. The samples were pooled and submitted to high-throughput sequencing (HTS) using the Illumina MiSeq platform and subsequently individually screened using a pancoronavirus RT-PCR protocol. We detected CoV-related sequences in HTS, but only two (2/101; 1.98%) animals had CoV detected in the intestines by RT-PCR. Partial sequences of RdRp and spike genes were obtained in the same sample and the RdRp region in the other sample. The sequences were classified as belonging to Alphacoronavirus. The sequences were closely related to alphacoronaviruses detected in vampire bats from Peru. The continuous monitoring of bat CoVs may help to map and predict putative future zoonotic agents with great impacts on human health.

Campylobacter fetus in abomasal fluid from spontaneously aborted bovine and ovine fetuses

Pregnancy losses are a major concern in livestock industry due to their economic impact on producers. Campylobacter fetus subspecies fetus (Cff) and C. fetus subspecies venerealis (Cfv) are directly related to reproductive failures in ruminants. Cff colonizes the gastrointestinal tract of a wide range of hosts leading to abortion, while Cfv is restricted to genital tract being generally associated to infertility in bovine. Considering the great economic losses related to campylobacteriosis in cattle and ovine herds, this study aims to investigate the occurrence of C. fetus, considering Cff and Cfv subspecies, in bovine and ovine spontaneously aborted fetuses in state of Rio Grande do Sul, Brazil. In this study, samples of abomasal fluid collected from 30 spontaneously aborted bovine (n = 18) and ovine (n = 12) fetuses were investigated for the detection of Campylobacter fetus throughout conventional PCR. Positive fetuses for C. fetus presence were further analyzed by molecular assays for Cff and Cfv detection, in order to determine subspecies identification. When available, samples of the main organs of the thoracic and abdominal cavities, as well as the brain, skeletal muscle, eyelid, skin, and placenta were collected for further histopathological analyses and bacterial culture, aiming to assess the presence of infection lesions and pathogens in those sites, respectively. Additionally, RT-qPCR assays were also performed for the detection of ruminant pestivirus, in order to detect bovine viral diarrhea cases. Throughout the present methodology, C. fetus was detected in the abomasal fluid samples of 2 bovine fetuses, being both identified as Cfv subspecies by PCR. Histopathological analyses demonstrated that macroscopic and microscopic changes found in the Cfv-positive animals were not either specific or directly related to Campylobacter infections. Moreover, no significant bacterial growth was observed in microbiological culture from the collected tissues, and both fetuses were negative for ruminant pestivirus. Differently, there was no detection of C. fetus in any of the analyzed ovine fetuses. Considering that abortion diagnosis rates reported in cattle and sheep industry are highly variable among the published studies, and that abortion diagnoses are commonly inconclusive due to difficulties in sampling methodology and inadequate identification of the pathogen involved, it is important to investigate the etiological causes of abortion the herds for better understanding the causes of pregnancy issues and monitoring their occurrence. In addition, the absence of pathognomonic lesions in the tissues investigated in the histopathological analyses observed in this study strongly suggests that well-known etiological agents commonly associated to abortion, such as Leptospira spp., Toxoplasma spp., Chlamydia spp. and Neospora caninum, are unlikely to be the cause of infection of the analyzed fetuses. Taking this into account, the presence of C. fetus in the abomasal fluid samples from two bovine fetuses demonstrated in the present study suggests the possible association of Cfv not only with infertility, but also with cases of bovine abortion, highlighting the importance of investigating unusual causal agents of abortions in sheep and cattle. Overall, an adequate diagnosis is essential for establishing better prevention strategies to avoid the circulation of abortion-related infectious agents in the herds.(AU)