Bovine Astrovirus and its Potential Role in Bovine Lymphocytic Encephalitis
Bibliographic record
Abstract
Astroviruses are a well-known cause of gastroenteritis in humans and many domestic animals. More recently, they have emerged as a cause of encephalitis in cattle and other species. Encephalitis is an economically important disease in cattle due to the death of animals. There is a zoonotic concern as many causes of encephalitis in cattle can cause disease in humans. It is therefore essential to determine the causes of encephalitis and their relative importance in a population. \nThis study sought to determine the frequency of bovine astrovirus infection in cases of encephalitis in adult cattle in Ontario and to examine the pathologic findings in positive cases. Thirty-five cases of idiopathic lymphocytic encephalitis were retrieved from the Animal Health Laboratory / Ontario Veterinary College archives. As controls, 32 animals with non-lymphocytic encephalitis and 40 animals with no neurologic disease or encephalitic lesions were selected. All animals were screened using RT-qPCR for bovine astrovirus. No controls tested positive for bovine astrovirus. Four of the 35 animals (11%) with lymphocytic encephalitis tested positive for astrovirus. The four positive cases of astrovirus encephalitis were investigated with immunohistochemistry. The perivascular cuffs and glial nodules were composed overwhelmingly of CD3+ T lymphocytes. \nTo investigate the historic role of bovine astrovirus encephalitis in Ontario cattle, an additional 21 cases from an older archive (1988-1998) were tested for bovine astrovirus, with 7 cases testing positive. In total, 56 cases of lymphocytic encephalitis were tested for astrovirus, and 11 tested positive (19.6 %). \nFor the remaining cases of idiopathic lymphocytic encephalitis, a PCR panel was performed to search for other known causative agents. This included rabies virus, WNV, EEEV, OHV-2, BVDV, BHV-1, Listeria monocytogenes, and Chlamydia species. Nine of these 45 remaining cases (20 %) tested positive for other agents (EEEV, L. monocytogenes, BVDV, BHV-1, and OHV-2), leaving 36 of the initial 56 idiopathic cases of encephalitis (64 %) without a definitive diagnosis. \nOverall, 19 % of cases of lymphocytic encephalitis without a previously identified cause in Ontario cattle, from 1990-2019, tested positive for bovine astrovirus. This virus is therefore an important causative agent of fatal lymphocytic encephalitis in Ontario.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".