Bovine astrovirus infection in feedlot cattle with neurological disease in western Canada.

Management of encephalitis, which can be fatal, requires understanding of a broad range of causative agents, pathophysiologic mechanisms, clinical syndromes, and outcomes.After completing this article, readers should be able to:The broad definition of the term "encephalitis," that is, inflammation of the brain, necessitates acknowledgment of the enormous inclusivity of the topic. The most common interpretation of the term implies a direct invasion of the brain by an infectious pathogen, most commonly, viral, fungal, or parasitic. The topic also includes examples of meningitis mediated by bacteria or other agents, which can produce extrameningeal symptoms such as lethargy or seizures, in which case, the combined term "meningoencephalitis" is used.There are also many examples of encephalitis not due to direct central nervous system (CNS) infections. Inflammatory processes due to an acute or chronic illness can result in an acute immune-mediated encephalitis, such as acute disseminated encephalomyelitis (ADEM), lupus cerebritis, and paraneoplastic syndromes. Agents or conditions that produce slowly progressive CNS symptoms, such as tertiary syphilis or "slow viruses" (the prion protein encephalopathies), also are considered examples of encephalitis. Table 1 lists only a limited number of the many pathogens and pathologic conditions that can cause either acute or subacute encephalitis. In this discussion, we will mainly address examples of acute encephalitis related to direct CNS infection and para-infectious processes involving the CNS. These examples embrace the major portion of the spectrum of disease presentation, course, and recovery, as well as mechanisms of cerebral injury.In addition to the taxonomic classification in Table 1, causes of infectious encephalitis often are grouped according to the most common methods of transmission. "Arboviruses" are those spread by insect vectors, such as West Nile virus (WNV) and the equine encephalitis group (both by mosquitoes). Zoonotic causes of encephalitis not spread by intermediary insect vectors include many of the parasitic infections (larva migrans) and rabies. Community-acquired encephalitides, such as enterovirus, adenovirus, and late-childhood herpesvirus infections, generally are spread by person-to-person contact. Vertically transmitted pathogens include neonatal herpes simplex (HSV), rubella virus, and cytomegalovirus, and likely many other viral agents. Vertical, symptomatic transmission of WNV has been well documented. Finally, sexual transmission is the major mechanism of infection for adult herpes simplex type 2 virus and HIV (which can produce an acute, often transient, meningoencephalitis in the absence of opportunistic infection).Iconic examples of parainfectious encephalitis in children include ADEM and acute cerebellar ataxia. Variants of these conditions, such as acute hemorrhagic leukoencephalitis and Bickerstaff brainstem encephalitis, are reported primarily in adult and older adult populations. Parainfectious syndromes are differentiated in practice from acute infectious encephalitis based upon clinical history and a lack of supporting evidence for direct CNS invasion. In the case of ADEM, there is usually an antecedent illness or immunization, followed 2 to 30 days later by various focal neurologic symptoms, possibly accompanied by signs of meningeal irritation. The early presentation may be confused with acute infectious encephalitis, and some instances of each phenomenon may be categorized incorrectly. Lumbar puncture findings can be variable, ranging from normal to a mild or moderate lymphocytic pleocytosis with an elevated protein concentration. Acute cerebellar ataxia follows a similar course of antecedent illness, but with symptoms limited to the cerebellum (ataxia, nystagmus, and cerebellar dysarthria).Infectious, parainfectious, and primary inflammatory causes of encephalitis are typically considered mutually exclusive. However, the example of Mycoplasma-related encephalitis illustrates some difficulty in differentiating direct versus indirect mechanisms of CNS disease, and the magnitude of the topic. Although widely regarded as a parainfectious phenomenon with variable pathology, up to 2% of these patients have Mycoplasma polymerase chain reaction (PCR)-positive cerebrospinal fluid (CSF), which might indicate some direct CNS invasion. Mycoplasma is a prevalent pediatric illness and cause of encephalitis. One hundred and eleven of 1988 patients referred to the California Encephalitis Project (CEP) tested positive for Mycoplasma pneumoniae; 76% of those affected were pediatric patients. (1)(2)Epidemiological data on encephalitis is organized according to identified agent. The CEP was initiated in 1998 for the collection of epidemiological data and is the most comprehensive database to date. It includes all referred immunocompetent individuals over 6 months of age and all clinical presentations, including chronic and slowly progressive encephalitis. Criteria for inclusion include encephalopathy or ataxia, plus at least one clinical finding (fever, seizures, focal neurologic deficits, CSF pleocytosis, abnormal neuroimaging, or abnormal EEG). By using a combination of CSF PCR, nasopharyngeal/throat specimen viral isolation, and acute and convalescent paired sera, all patients receive testing for herpesviruses, arboviruses, enteroviruses, respiratory viruses, measles virus, Chlamydia species, and M pneumoniae. Between 1998 and 2005, 1,570 patients were enrolled. A confirmed or probable causative agent was identified in only 16% of cases. Of identifiable causes, 69% were viral, 20% bacterial, 8% noninfectious (ie, autoimmune disease), 7% prion protein, 3% parasitic, and 1% fungal. Extensive testing procedures still revealed no identifiable cause in 63% of patients. (3) Among the more prominent causes of viral encephalitis, HSV accounted for only 2.5% of the CEP cases; in contrast, HSV was identified in 5% of 322 pediatric patients with acute encephalitis seen in one series between 1994 and 2005. (4)Epidemics of infectious encephalitis have always attracted much media attention, such as the WNV outbreak first seen in the United States in New York City in 1999. Between 1999 and 2007, 1,478 pediatric cases of confirmed WNV infection occurred in the United States, of which 443 (30%) had neurologic involvement. Of those with neurologic symptoms, there were three fatalities. Overall, children accounted for only 4% of reported WNV infection cases, with an estimated median annual incidence of 0.07 per 100,000. The pediatric fatality rate contrasts favorably with the 12% mortality rate from the 1999 epidemic, in which the majority of symptomatic cases were elderly people. WNV is now an epidemiological risk factor throughout the contiguous United States and the Caribbean. (5) Although WNV remains the most commonly encountered arboviral encephalitis agent, California encephalitis viruses have the greatest proportion of pediatric symptomatic infections (88% of cases), and eastern equine encephalitis has the highest overall mortality rate of 42%.The importance of local epidemiological information and seasonality cannot be ignored. Many cases of viral encephalitis either occur in epidemics, display a clear seasonal predilection, or both. For example, enteroviruses are most often seen in spring and summer; arthropod-borne illnesses, in the summer and fall. Respiratory virus-mediated cases often are specific to fall and winter. These elements of conventional epidemiological wisdom, however, should be subordinate to locally observed trends, such as cases of H1N1 influenza encephalitis observed during an out-of-season epidemic.In contrast, ADEM tends to be more sporadically observed than many infectious causes, although population data in the United States have supported a winter-spring predilection for the condition. Recent data from Canada, however, failed to show this seasonality. (6) The inclusion criteria for ADEM strongly influences reported incidence, producing wide variations, with a range of 0.2 to 0.8 per 100,000 children in the United States and Canada, and 0.07 per 100,000 in Germany. Antecedent infectious illness or vaccination typically is identified in 50% to 75% of patients. Presenting symptoms are highly variable, as the range of reported incidences of any one neurologic symptom in pooled study data suggest. Outcomes statistics are similarly scattered, with a 57% to 89% reported rate of full recovery.Infectious agents and parainfectious processes are presumed to mediate their acute symptoms through any combination of postulated mechanisms listed in Table 2. Evidence is best for the causes of fatal cases, in which wholesale parenchymal destruction is usually identifiable at necropsy, including direct neuronal and glial invasion with apoptosis, neuronophagia, vascular occlusion leading to infarction, and secondary effects of cerebral edema.Evidence supporting largely immune-mediated mechanisms of injury (cytotoxic antibodies, cytokine effects, etc) is less direct, and more evident in parainfectious/inflammatory causes of encephalitis. In ADEM fatalities, perivenular lymphocytic infiltration with local myelinolysis is a hallmark finding on pathology specimens. (12) Evidence supporting the concept of antibody-mediated mechanisms derives mainly from the clinical efficacy of intravenous immune globulin (IVIG) and plasmapheresis in the treatment of ADEM. Demonstration of antibody targeting precise CNS molecules in human ADEM and other demyelinating disease cases is scarce, with poor concordance, even between individuals who have similar syndromes. Existing knowledge of autoantibodies targeting specific CNS molecules is derived mainly from experience with paraneoplastic syndromes in adults, eg, anti-Yo, anti-Hu, and anti-Purkinje cell antibodies. These mechanisms, however, produce subacute encephalitis or cerebellitis distinct from typical pediatric ADEM. Even in children with classic postinfectious cerebellitis, fewer than half display anti-Purkinje cell antibodies.The lack of routinely detectable autoantibody in parainfectious CNS disease is likely attributable to both the large number of causative infectious agents and the multiplicity of possible targeting mechanisms. The latter may include both molecular mimicry and abnormal handling of normally occurring cellular antigens. For example, an invading virus may manufacture proteins that share epitopes with normal human myelin (mimicry), or may produce enzymes that cleave or misfold normal host proteins into immunologically unrecognized forms. For example, vaccinia virus core protein kinase cleaves myelin basic protein.Even more difficult is the isolation of cytokine effects in producing CNS injury. Interleukins 6 and 8, interferon γ, and tumor necrosis factor α seem to be among those cytokines most commonly identified as correlating with severity of disease course or outcomes across multiple causes of encephalitis, both infectious and noninfectious (eg, lupus cerebritis), but with high variability between specific agents. High concentrations of interleukins 6 and 8 can be found in the CSF of patients with Mycoplasma encephalitis and Japanese encephalitis. Higher titers in a small number of Japanese encephalitis patients seemingly correlated with a lower survival rate. It is unclear if cytokines are causative of further CNS injury or are active markers of disease severity.The typical presentation of acute encephalitis consists of any combination of altered mental status, seizures, other behavioral changes, weakness, sensory disturbances, or nonepileptic movement disorders, in the absence of an identifiable external cause, such as intoxication, traumatic brain injury, or psychosocial stressors. In the younger child or infant, symptoms may be even less distinct, and can include uncharacteristic somnolence, disinterest in feeding, weak suck, irritability, loss of head control, or abnormal eye movements. Further clinical clues may include the presence of fever (either acutely or in the 1–4 week interval before the onset of symptoms), or meningeal irritation (Table 3). However, these supporting clues may not be apparent upon first presentation. Because the clinical symptoms of encephalitis include a very broad range in both scope and severity, suspicion should be high in the approach to any child presenting with uncharacteristic behavior that is persistent and disproportionate to environmental and situational factors.Upon identification of a suspected case of encephalitis, a relatively short but critical series of steps should be executed, as summarized in Table 4. Additional facts to consider in the initial evaluation of the patient include seasonal presentation, history of immunosuppression, travel history, recent local epidemiological information, and presence of focal neurologic symptoms or deficits. Table 5 lists additional specific testing that should be routinely considered based upon protocols developed for the CEP and specific clinical settings. Table 6 lists, according to clinical clues, other viral causes of encephalitis that would require agent-specific testing if suspected.In patients in whom a parainfectious process is suspected, acute testing for demyelinating inflammatory conditions is increasingly popular. This testing is motivated by the increasing recognition of pediatric multiple sclerosis (MS) and other demyelinating conditions, eg, neuromyelitis optica (Devic disease), which may be mistaken initially for ADEM. Signs that increase suspicion for MS-related conditions include the presence of exclusively white matter abnormalities on MRI (especially if monolesional), optic neuritis, isolated myelitis, a recurrent or polyphasic disease course, or postadolescent age. In these cases, standard lumbar puncture studies also include myelin basic protein assay and measurement of CSF immunoglobulins with oligoclonal banding, and concomitant serum protein electrophoresis. Although the presence of disproportionate oligoclonal antibody production within the CSF is more suggestive of idiopathic demyelination (eg, MS), this finding is not sufficiently specific to prove a diagnosis of MS because ADEM and other CNS inflammatory conditions, including CNS infection, can produce similar results. The neuromyelitis optica antibody often is present in cases having optic neuritis associated with spinal cord symptoms. Documented neuromyelitis optica antibody-positive patients also have presented with optic neuritis only.In following the standard evaluation of patients with symptoms of encephalitis, the diagnostic testing results most commonly encountered include either unremarkable or variable leukocytosis or lymphocytosis. Comprehensive metabolic panels often fail to demonstrate specific abnormalities. Some enteroviral infections can produce a sepsislike syndrome with more remarkable hematologic abnormalities. Neonatal HSV infections sometimes produce hepatic function abnormalities and disseminated intravascular coagulation. Inappropriate secretion of antidiuretic hormone can be seen in almost any encephalitic process, but is reported more commonly in St Louis encephalitis (primarily a disease of the elderly population) and WNV infections.Understanding clinical-anatomic correlations may be helpful in refining the differential diagnosis, because some causes of encephalitis display tropism for specific CNS tissues. Table 3 describes the cardinal symptoms of infection or inflammation in major anatomic subdivisions, as well as commonly used clinical terms. Although the anatomic localization is an important part of initial symptom recognition, neuroimaging plays an indispensable role, whether or not localizing clinical symptoms are present. In the very young child, clinically based neuroanatomic localization also can be notoriously difficult. Table 7 describes some classically cited agent-specific localization-related findings, identifiable by symptoms, neuroimaging, or both. However, a high degree of variability in clinical presentations mandates that the search for an etiologic agent cannot be confined strictly to those agents classically injurious to specific CNS locations.Neuroimaging, including MRI, early in the course of disease may sometimes yield false-negative results. For purposes other than identifying substantial cerebral edema, midline shift or hemorrhage, computed tomography imaging generally is not sufficient for the diagnostic workup of encephalitis.The lumbar puncture is the single most utilized test for the diagnosis of encephalitis. The primary results, however, generally lack specificity, and can be normal early in the course of the disease. In those patients displaying abnormal CSF results, the most characteristic findings are increased opening pressure, normal or elevated protein concentration, normal glucose level, and pleocytosis, which often begins with polymorphonuclear leukocytes and then converts to lymphocytic, or sometimes monocytic, predominance with progression of the disease. Although there are reported variations on this theme with certain etiologic agents, such as hemorrhagic pleocytosis with HSV, atypical lymphocytes with Epstein-Barr virus, or mononuclear leukocytes with echovirus or varicella-zoster infection, there are no pathognomonic CSF findings that help to differentiate infectious cases of encephalitis.The ability to obtain PCR amplification of viral DNA fortunately has added new usefulness to the lumbar puncture in encephalitis. This modality, however, requires clinical suspicion of a specific diagnostic entity, and is not available as a broad "battery" of testing. Additionally, viral DNA often is not recovered in certain stages of illness. For example, 5% to 10% of adult cases of HSV meningitis have negative PCR results upon the first lumber puncture. Furthermore, results often are not immediately available, and can take from 1 to 7 days or longer to be available. Hence, the decision to use specific antibiotic or antiviral treatments, such as acyclovir for suspected HSV meningitis, is still largely predicated upon clinical suspicion.Parainfectious encephalitis such as ADEM or acute cerebellar ataxia may manifest many of the same CSF findings as infectious encephalitis. However, pleocytosis tends to be less dramatic in most, but not all, parainfectious cases. When pathogen genomic material can be isolated from the CSF, the likelihood of a parainfectious or purely inflammatory etiology becomes remote.The most reliable standard for demonstrating causation of acute infectious encephalitis remains the pairing of acute and convalescent serum titers. A fourfold rise in titer, especially immune globulin M, against a suspected agent is most often considered diagnostic. This method is limited by the adequacy of follow-up and the accuracy of testing selection. Many patients are discharged and lost to close follow-up long before convalescent titers are obtainable. Of those tested, the causative agent may be missed by clinical suspicion-guided testing targeting other organisms erroneously.The priority in the treatment of acute encephalitis is the duality of clinical stabilization and containment of potentially damaging inflammatory processes. Because many patients present with any combination of seizures, delirium, autonomic instability, and respiratory irregularities, treatment of these acute symptoms often takes priority. This stabilization should not, however, delay addressing the suspicion of either an infectious or parainfectious condition and initiating appropriate treatment. Commonly, such patients are empirically treated with intravenous acyclovir while waiting for lumbar puncture, or while waiting for laboratory results, including HSV PCR. Either because of delays in obtaining these results, or because of the known false-negative rate of PCR testing of acute CSF specimens, many will complete the required 21-day course of acyclovir without a firmly established laboratory diagnosis.The emphasis on prompt treatment of possible HSV encephalitis should not overshadow a thorough search for clues to other causative agents. Table 5 lists some alternative considerations in the diagnosis of acute infectious encephalitis that might affect treatment options.Beyond the primary infectious considerations, ADEM ranks as the most likely cause of an acute encephalitis. The constellation of a temporally separate infectious illness or an immunization before the onset of symptoms, multiple encephalitic symptoms, and multifocal MRI abnormalities in both gray and white matter are highly suggestive (but not pathognomonic) for the diagnosis of ADEM. Treatment varies substantially from the approach to acute infectious encephalitis in that high-dose corticosteroids are a first-line treatment, followed by IVIG or plasmapheresis in cases refractory to corticosteroid treatment. The use of both IVIG and plasmapheresis remains unsupported by clinical trials; but IVIG has received wider acceptance as an alternative treatment at this time.The use of corticosteroids in the setting of nonherpetic infectious encephalitis remains controversial. Outside of single case reports, the only available supportive evidence for their use derives from the treatment of progressive multifocal leukoencephalopathy, a subacute/chronic encephalitis caused by polyomavirus JC that primarily in of cerebral as or over 2 of is a critical in infectious encephalitis. is a variable finding in encephalitis. by is an important of treatment. In a series of children with meningitis or of patients with 3 of with at symptomatic and fluid are the most is used on a limited as case and small series However, the of use is limited by the of with of the and the possible of active agents into the This may result in the of cerebral more fail and is isolated and small series to the use of for treatment of symptomatic often becomes a of in patients with encephalitis. In the of patients Of patients developed or This group of patients a mortality with an overall mortality rate for the agent known has been used in the treatment of patients with acute symptomatic agents most are available in intravenous and include agents and The typical approach begins with upon recognition of either recurrent or followed by of a more with to in some are still most commonly used but agents such as or are either high or fail to of or agent as the most likely treatment, including the use of or this of treatment, usually is motivated both by the of in the patient and the to a as a of the adequacy of other are added to the treatment either as intravenous or or other direct during the of the with and agents. The use of is to both more as well as a more the of the agent without However, metabolic can to obtain of any or all agents in often are used as a treatment of use of or has limited results as In the longer the of the the for full and outcomes of both infectious and inflammatory encephalitis range from full to The of clinical remains can be identified that strongly the for of the infectious agent or process, age of the of primary cerebral and spinal cord presence of cerebral edema, of cerebral and vascular injury, presence of other system disease and and to treatment The importance of the of infectious disease in should not be This is especially in neonatal encephalitis accompanied by sepsislike syndromes, infectious or which may produce mortality Even among older disease especially as in the epidemics, in which the survival rate was among those in the acute of illness. of is for of encephalitis In to this much upon the causative agent. a agents that produce more cerebral necrosis (especially if or brainstem injury is or vascular disease have available statistics in The specific etiologic agent some for example, of patients who have HSV encephalitis some identifiable neurologic in some among children affected by had no detectable the encephalitis. for more even in cases there are no deficits, remains a topic. For example, of children 3 to 7 meningitis or encephalitis, 20% symptoms, with only 3% of The incidence of similar neurologic in other causes of encephalitis remains largely at this

We thank Dr Eisenhut for his interest in our prospective 12-year study of herpes simplex encephalitis in children.1 Because of the standardized comprehensive prospective microbiologic investigations performed on all children who were admitted to our institution with acute encephalitis, evidence of infection with >1 potential pathogen is often observed. This approach is very different from retrospective reviews of cases in which the final diagnosis is the point of entry into the study. In a recent review of our data, approximately one fourth of the cases showed evidence of infection (of variable strength) with ≥2 pathogens.2 In situations such as this, it is often not possible to determine with certainty which pathogen is the causative agent. Furthermore, in some cases, >1 of the potential pathogens may be playing a role.In regard to the specific cases mentioned by Dr Eisenhut, we disagree with his conclusion that Mycoplasma pneumoniae is the more likely pathogen. We believe that most experts would consider the detection of herpes simplex virus (HSV) in the cerebrospinal fluid (CSF) by polymerase chain reaction (PCR) as strong evidence of causality irrespective of HSV serologic results or microbiologic evidence of infection with other potential pathogens. The failure to detect a rise in complement fixation titer to HSV (cases 7 and 8) between acute and convalescent sera could be a result of the well-known limited sensitivity of this assay.3,4 In regard to case 9, it is possible that the convalescent sample was obtained too early (51 days) for HSV seroconversion to have occurred. In 1 prospective study of HSV seroconversion, the median time between onset of genital tract symptoms and seroconversion was 56 days (interquartile range: 16–121 days).5 In addition, there is a paucity of data on the sensitivity of HSV serology in the setting of HSV encephalitis. We acknowledge that when both HSV and M pneumoniae are detected by PCR in the CSF (cases 7 and 9), it is difficult to assign causality solely to 1 pathogen. To avoid subjective assignment of causality, we set rigid inclusion criteria for herpes simplex encephalitis; these criteria are detailed in the methods section of our article.1Dr Eisenhut refers to “local reactivation” of HSV as a possible explanation for the delayed detection of HSV in the CSF of case patient 9. We do recognize that local reactivation (not causally related to the encephalitis) may be an explanation for some patients with positive HSV CSF PCR results but believe this to be unlikely in this case because of the aforementioned stringent criteria used to define HSV encephalitis. We did exclude several cases in which HSV was detected in the CSF by PCR because of a clear alternative diagnosis or absence of typical CSF, electroencephalographic, or neuroimaging findings, again in accordance with preselected exclusion criteria. As discussed in our article, we support a full course of therapy for possible HSV encephalitis for children in whom HSV is detected in the CSF by PCR irrespective of the suspected cause of the encephalitic process. In addition, it has been shown that the detection of HSV in the CSF by PCR of patients with HSV encephalitis can be delayed.6 Hence, HSV should not be excluded as a possible cause of encephalitis solely on the basis of a single negative CSF PCR assay, particularly if the lumbar puncture was performed during the first 48 to 72 hours of illness.We agree that M pneumoniae is an important cause of acute encephalitis in children and that additional research into the role of this pathogen in neurologic disease is needed. In a previous publication pertaining to M pneumoniae and acute childhood encephalitis, we stratified cases into probable, possible, and indeterminate categories in accordance with the strength of microbiologic evidence implicating M pneumoniae as the cause.7 Accordingly, M pneumoniae was considered to be the probable cause of 6.9% of the acute childhood encephalitis cases. As indicated in that article, cases in which the only evidence of M pneumoniae infection was serologic were often associated with more compelling evidence of infection with other potential pathogens. This observation suggests that many of the positive immunoglobulin M assays for M pneumoniae were probably falsely positive, perhaps as a result of cross-reactivity of M pneumoniae antigens and human brain antigens8–10 or other inherent limitations in the specificity of serologic tests for M pneumoniae.11Determining the etiology and pathogenesis of acute childhood encephalitis remains a major hurdle to the appropriate management of this condition. Ultimately, new innovative diagnostic and treatment strategies will be needed to improve the outcome of this often devastating entity.

The etiology of viral encephalitis in cattle often remains unresolved, posing a potential risk for animal and human health. In metagenomics studies of cattle with bovine non-suppurative encephalitis, parainfluenza virus 5 (PIV5) was identified in three brain samples. Interestingly, in two of these animals, bovine herpesvirus 6 and bovine astrovirus CH13 were additionally found. We investigated the role of PIV5 in bovine non-suppurative encephalitis and further characterized the three cases. With traditional sequencing methods, we completed the three PIV5 genomes, which were compared to one another. However, in comparison to already described PIV5 strains, unique features were revealed, like an 81 nucleotide longer open reading frame encoding the small hydrophobic (SH) protein. With in situ techniques, we demonstrated PIV5 antigen and RNA in one animal and found a broad cell tropism of PIV5 in the brain. Comparative quantitative analyses revealed a high viral load of PIV5 in the in situ positive animal and therefore, we propose that PIV5 was probably the cause of the disease. With this study, we clearly show that PIV5 is capable of naturally infecting different brain cell types in cattle in vivo and therefore it is a probable cause of encephalitis and neurological disease in cattle.

Encephalitis is a frequently diagnosed condition in cattle with neurological diseases. Many affected animals present with a nonsuppurative inflammatory reaction pattern in the brain. While this pattern supports a viral etiology, the causative pathogen remains unknown in a large proportion of cases. Using viral metagenomics, we identified an astrovirus (bovine astrovirus [BoAstV]-CH13) in the brain of a cow with nonsuppurative encephalitis. Additionally, BoAstV RNA was detected with reverse transcription-PCR and in situ hybridization in about one fourth (5/22 animals) of cattle with nonsuppurative encephalitis of unknown etiology. Viral RNA was found primarily in neurons and at the site of pathology. These findings support the notion that BoAstV infection is a common cause of encephalitis in cattle. Phylogenetically, BoAstV-CH13 was closely related to rare astrovirus isolates from encephalitis cases in animals and a human patient. Future research needs to be directed toward the pathogenic mechanisms, epidemiology, and potential cross-species transmission of these neurotropic astroviruses.

Viral meningoencephalitis is highly heterogeneous, varying by geographic location. The aim of this study was to characterize the etiology and reporting the clinical findings and outcome of viral encephalitis in children in southern Brazil. A cross-Sectional study was conducted at Hospital Pequeno Príncipe, Curitiba, Brazil, between January 2013 and December 2017. It included patients younger than 18 years, who fulfilled the criteria: altered mental status as a major criteria and 2 or more minor criteria (1) fever, (2) seizures, (3) focal neurologic findings, (4) central system fluid white cell count of ≥5 cells/mm, (5) abnormal brain imaging, and/or (6) electroencephalogram abnormalities. Viral meningoencephalitis was diagnosed in 270 children, with median age of 2 years (interquartile range: 0-4), The etiology of viral meningoencephalitis was confirmed in 47% of patients. Enterovirus (18%) was the major cause of encephalitis in Southern Brazilian children, and a high prevalence of Epstein-Barr virus (6%) was demonstrated. Most patients presented with fever (81%), followed by vomiting (50%), focal neurologic findings (46%), seizures (31%) and headache (30%). Few abnormalities were detected on electroencephalograms and brain magnetic resonance images. On discharge from hospital, symptoms resolved completely in 87% of children. Sequelae were mainly observed in patients with focal neurologic symptoms (P<0.001), presence of seizures (P<0.001) and electroencephalogram abnormalities (P=0.024). Enterovirus was the major cause of encephalitis. Etiologic agent of encephalitis seems to be influenced by the local virologic pattern. A poor outcome was identified in patients with seizures, focal neurologic findings and electroencephalogram abnormalities.

Molecular mechanisms of neuroinflammation and injury during acute viral encephalitis

Japanese encephalitis virus is the major cause of encephalitis in India. To control the increasing incidence and fatal outbreaks, SA 14-14-2 vaccine was introduced initially in 104 endemic districts in phased manner from 2006 to 2011. As there is no data available before 2008 on the number of Japanese encephalitis (JE) cases excluding cases of Acute Encephalitis Syndrome (AES), a four year average of the number of JE vs. AES cases reported during 2008– 2011 was calculated and the value was used to determine the percentage of JE cases out of AES cases for the period 1994 to 2007. The analysis of data for the period 1994 to 2017 showed that there was a substantial increase of JE cases after the initiation of vaccination in 2006. Since the JE vaccination was given only in selected districts, comparing the vaccinated district with non vaccinated district would be more appropriate to determine the impact of vaccination. However, the data available on JE is only at the state wide. Hence, Tamil Nadu state where, district-wise JE data is available from 1993 onwards was used as a model state to determine the impact of vaccination. Even though the data for entire Tamil Nadu state showed an increasing trend, the analysis of data for vaccinated districts reveals that, the increase was due to increase of JE cases in non-vaccinated districts. It shows that, there was a reduction in JE case incidences in the vaccinated districts of Tamil Nadu in particular and India as a whole following the introduction of SA 14-14-2 vaccination.

Japanese encephalitis virus (JEV) is a major cause of encephalitis in Asia. We estimated the diagnostic accuracy of two anti-JEV immunoglobulin M (IgM) enzyme-linked immunosorbent assays (ELISAs) (Panbio and XCyton JEVCheX) compared with a reference standard (AFRIMS JEV MAC ELISA) in a prospective study of the causes of central nervous system infections in Laos. Cerebrospinal fluid (CSF; 515 patients) and serum samples (182 patients) from those admitted to Mahosot Hospital, Vientiane, were tested. The CSF from 14.5% of acute encephalitis syndrome (AES) patients and 10.1% from those with AES and meningitis were positive for anti-JEV IgM in the reference ELISA. The sensitivities for CSF were 65.4% (95% confidence interval [CI] = 51–78) (Xcyton), 69.2% (95% CI = 55–81) (Panbio), however 96.2% (95% CI = 87–100) with Panbio Ravi criteria. Specificities were 89–100%. For admission sera from AES patients, sensitivities and specificities of the Panbio ELISA were 85.7% (95% CI = 42–100%) and 92.9% (95% CI = 83–98%), respectively.

Este trabalho relata uma clonagem e seqüenciamento das subunidades alfa e beta do hormônio folículo estimulante de Bos taurus indicus. Também apresenta os resultados de comparação realizada das seqüências gênicas dessas cadeias com as seqüências das cadeias alfa e beta do FSH de suínos e da cadeia beta de bovinos Bos taurus taurus já presentes no GenBank. Na comparação das seqüências de nucleotídeos e de aminoácidos predita da cadeia ?FSH de Bos taurus indicus com as cadeias ?FSH de outras espécies como suínos e búfalo (Bubalis bubalis), observou-se que as seqüências são bastante similares. A comparação da seqüência da subunidade ?FSH de Bos taurus indicus com a de suíno demonstrou diferenças em três resíduos de aminoácidos. Na comparação com ßFSH, registrou-se modificação na primeira base do codon que levou à alteração no resíduo do aminóacido 83, que, em Bos taurus indicus, é uma glicina, ao invés da serina presente em Bos taurus taurus. Confirmaram-se essa modificação e todas as outras identificadas na seqüência dos cDNA das cadeias ?FSH e ?FSH em outra clonagem. A modificação Ser para Gly na posição 83 foi a única que alterou a identidade do resíduo de aminoácido na comparação entre as subunidades beta do FSH de Bos taurus indicus e Bos taurus taurus. Contudo, ela não deve alterar significativamente as propriedades fisiológicas do FSH, uma vez que o resíduo de glicina encontrado nessa posição também é encontrado na cadeia ?FSH suína. Trata-se, portanto, de uma modificação particular que distingue as cadeias ?FSH de B. taurus taurus e B. taurus indicus. PALAVRAS-CHAVES: Bovino, clonagem, FSH, hormônio.

Astroviruses (AstVs) cause gastrointestinal disease in mammals and avians. Emerging evidence suggests that some AstVs have extraintestinal tissue tropism, with AstVs detected in the liver, kidney, central nervous system, and the respiratory tract variably associated with disease. In cattle, AstV infection has been linked to gastroenteric or neurologic disease. Here, metagenomic sequencing of a lung from a bovine with respiratory disease identified a novel AstV with a predicted capsid-encoding ORF2 amino acid sequence with 66% identity to caprine astrovirus (CAstV G2.1). A quantitative reverse transcription PCR (qRT-PCR) targeting ORF2 found four out of 49 (8%) lungs and one out of 48 (2%) enteric samples obtained from bovine diagnostic submissions positive for the novel bovine astrovirus (BAstV). In two strongly qRT-PCR-positive lung samples, intense novel BAstV nucleic acid signals were mainly localized in the cytoplasm of alveolar macrophages and mononuclear cells using RNAscope® in situ hybridization (ISH). Genetic analysis of two novel BAstV genomes determined from qRT-PCR positive samples found high similarity for ORF1ab nucleotide sequence (92.1% and 93.9%) to BAstV strain BSRI-1, while ORF2 nucleotide sequence was most similar to CAstV G2.1 (74.6% and 77.6%). Phylogenetic analysis of the novel BAstV sequences found a close genetic relationship to the single BAstV (BSRI-1) previously identified from a bovine respiratory sample as well as bovine and caprine AstVs identified from various tissues. Further research is needed to determine the clinical significance of BAstV in respiratory diseases.

Cattle have been invaluable for the transition of human society from nomadic hunter‐gatherers to sedentary farming communities throughout much of Europe, Asia and Africa since the earliest domestication of cattle more than 10,000 years ago. Although current understanding of relationships among ancestral populations remains limited, domestication of cattle is thought to have occurred on two or three occasions, giving rise to the taurine (Bos taurus) and indicine (Bos indicus) species that share the aurochs (Bos primigenius) as common ancestor ~250,000 years ago. Indicine and taurine cattle were domesticated in the Indus Valley and Fertile Crescent, respectively; however, an additional domestication event for taurine in the Western Desert of Egypt has also been proposed. We analysed medium density Illumina Bovine SNP array (~54,000 loci) data across 3,196 individuals, representing 180 taurine and indicine populations to investigate population structure within and between populations, and domestication and demographic dynamics using approximate Bayesian computation (ABC). Comparative analyses between scenarios modelling two and three domestication events consistently favour a model with only two episodes and suggest that the additional genetic variation component usually detected in African taurine cattle may be explained by hybridization with local aurochs in Africa after the domestication of taurine cattle in the Fertile Crescent. African indicine cattle exhibit high levels of shared genetic variation with Asian indicine cattle due to their recent divergence and with African taurine cattle through relatively recent gene flow. Scenarios with unidirectional or bidirectional migratory events between European taurine and Asian indicine cattle are also plausible, although further studies are needed to disentangle the complex human‐mediated dispersion patterns of domestic cattle. This study therefore helps to clarify the effect of past demographic history on the genetic variation of modern cattle, providing a basis for further analyses exploring alternative migratory routes for early domestic populations.

On December 23, 2003, Bovine Spongiform Encephalopathy (BSE), widely known as 'mad cow disease,' was found in the state of Washington. Major beef importing countries, including Japan, South Korea, and Mexico, banned imports of beef and beef products produced in the United States. A single case of BSE occurred on May 20, 2003, in Canada, prompting the United States to close its border to Canadian beef products. Prior to these BSE outbreaks in North America, the disease was detected in the United Kingdom and Japan. U.S. consumer response to the BSE outbreak in Washington is unknown. However, the previous cases which occurred in the United Kingdom and Japan indicate that the BSE outbreaks reduced domestic consumption of beef produced in the countries and increased beef imports from BSE-free countries, suggesting that consumers in the United States may respond negatively to the BSE outbreak and reduce their consumption of beef. Based on consumer response to BSE outbreaks in the United Kingdom and Japan, the BSE outbreak in Washington could reduce domestic consumption by 10% and exports by 75%, which could decrease the price of beef about 15%, from 370cents/lb in the third quarter of 2003 to 313.7cents/lb. However, prices of pork and chicken would increase about 3%, as consumers in this country switch from beef to pork and chicken consumption. The decreased consumption and export of beef will affect prices of slaughter and feeder cattle accordingly. The price of slaughter cattle would decrease about 13.5%, and the price of feeder cattle would decrease about 16% in the United States. If there are additional BSE outbreaks in the United States, the impacts will be much more significant. Domestic consumption of beef could decrease more than 20%, and U.S. exports would shutdown completely. In this case, the domestic price of beef could decrease 26%. Prices of slaughter and feeder cattle would decrease accordingly, about 20.9% and 24.5%, respectively, which could destroy the U.S. beef and cattle industry. To isolate a future BSE outbreak in the region, it is important to improve traceability of the infected animals by introducing both country of origin and regional labeling and preserve it through the supply chain. If the labeling system is developed for the United States, and if U.S. processors could segregate cattle based on its origin by labeling, the impacts of BSE outbreaks on the U.S. beef/cattle industry could be less prominent. Labeling would allow U.S. and foreign consumers to distinguish beef coming from BSE-free regions in the United States.

Viral encephalitis.

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Until the advent of a vaccine, the most common cause of bacterial meningitis in Australia used to be Haemophilus influenzae type b (Hib). Since a vaccine was introduced, the two most common bacterial causes of meningitis in children are Neisseria meningitidis and Streptococcus pneumoniae. Viral meningitis is usually much less severe than bacterial meningitis, except in cases where the virus has caused encephalitis as well as meningitis. Viral causes of meningitis or encephalitis include varicella zoster, influenza, mumps, measles and until recently, polio. Many of these infections can be prevented with immunization, and following extensive preventive programmes for these viruses, enteroviruses have now become the most common cause of viral meningitis. Fungal infections of the central nervous system may also occur. The most common form of fungal meningitis is caused by the fungus Cryptococcus neoformans. Cryptococcal meningitis is common in AIDS patients. Although treatable, fungal meningitis often recurs in nearly half of affected persons. Arboviruses are the primary cause of acute encephalitis whilst herpes viruses are the other major cause of encephalitis in the developed world. Despite advances in antiviral therapy over the past two decades, herpes simplex encephalitis (HSE) remains a serious illness with significant risks of morbidity and death. The accurate diagnosis of encephalitis and meningitis due to infectious agents has been difficult using traditional methods. The introduction of molecular diagnostic assays has greatly facilitated their diagnosis, but clinical (CSF) samples need to be collected early in the infection process to maximize the likelihood of pathogen detection.