Swine polioencephalomyelitis in Brazil: identification of Teschovirus A, Sapelovirus A, and Enterovirus G in a farm from Southern Brazil.

Porcine encephalomyelitis can be associated with many etiologies, including viral agents, such as Porcine teschovirus (PTV), Porcine sapelovirus (PSV), and Porcine astrovirus (PoAstV). In this study, we investigated the presence of these viruses in a neurological disease outbreak in a swine farm in Southern Brazil. The piglet production farm unity had 1200 weaning piglets, and 40 piglets with neurological signs such as motor incoordination, paresis, and paralysis of hind limbs, with an evolution time of approximately 4 days. Among these, 10 piglets were submitted to postmortem examination. Gross lesions were restricted to a mild enlargement of the nerve roots and ganglia of spinal cord segments. The microscopic lesions were characterized by nonsuppurative encephalomyelitis and ganglioneuritis with evident neuronal degeneration and necrosis. Samples of the central nervous system (CNS), cerebrospinal fluid, and feces were collected and submitted to molecular analysis. PTV was identified in all samples of the CNS, while eight of the piglets were also positive for PSV, and seven were positive for Porcine enterovirus (EV-G). PoAstV was identified in a pool of feces of healthy animals used as controls. This study demonstrates the occurrence of encephalomyelitis associated with PTV on a swine farm in Southern Brazil, as well as the presence of other viruses such as PSV, EV-G, and PoAstV in the swineherd. Sequences of the fragments that were previously amplified by PCR showed a high similarity to PTV 6. Herein, we describe the first case report of severe swine polioencephalomyelitis associated with PTV in South America.

Survival analysis in non-congenital neurological disorders related to dengue, chikungunya and Zika virus infections in Northeast Brazil.

The Northeast of Brazil has experienced a triple epidemic, with the simultaneous circulation of dengue virus (DENV), chikungunya virus (CHIKV) and Zika virus (ZIKV), which may have contributed to the observed increase across this region of atypical forms of disease and deaths. In view of this fact, non-congenital neurological disorders related to arboviruses were compared with other etiologies, mortality and survival rates of patients admitted to referral neurology hospitals in Pernambuco State, Northeast Brazil, from 2015 to 2018. Blood and cerebrospinal fluid samples were collected and tested using molecular and serological assays. The arbovirus-exposed groups were compared with respect to epidemiological, clinical and neurologic characteristics by using the Pearson's chi-square test. For the survival analysis, the Kaplan-Meier and Hazard Ratio (HR) tests were used, with a 95% confidence interval (CI). Encephalitis and encephalomyelitis were more frequent in arboviruses, while myelitis predominated in the neurological disorders of other etiologies. Guillain-Barré Syndrome (GBS) was similarly distributed amongst the groups. Exposure to one of the arboviruses caused a six-fold increase in the risk of death (HR: 6.37; CI: 2.91 - 13.9). Amongst the arbovirus-exposed groups, infection (DENV/CHIKV) increased nine times the risk of death (HR: 9.07; CI: 3.67 - 22.4). The survival curve indicates that have been exposed to some arbovirus decreased the likelihood of survival compared to those with other etiologies (Log-Rank: p<0.001). Within this scenario, neurologic manifestations of DENV, CHIKV and ZIKV have the potential to increase mortality and decrease survival, and concomitant infection (DENV/CHIKV) is an aggravating factor in reducing the likelihood of survival when compared to monoinfections.

Pathological, immunohistochemical, and molecular findings of equine protozoal myeloencephalitis due to Sarcocystis neurona infection in Brazilian horses.

Equine protozoal myeloencephalitis (EPM) is an important neurologic disease of horses in the American continent caused by Sarcocystis neurona and Neospora hughesi infection. This study describes the pathological, immunohistochemical, and molecular findings of fatal cases of EPM in southern Brazil. A review was performed on a total of 13 cases compatible with EPM, which were diagnosed by postmortem examination in the period of 2010-2017. Epidemiological information was obtained from necropsy reports. Gross and histological lesions were characterized, and cases were subjected to immunohistochemistry anti-Sarcocystis neurona, Toxoplasma gondii, and Neospora spp. Molecular search was performed using ITS-1 gene PCRs. Microscopic lesions were multifocal in all cases, and more frequently observed in the spinal cord segments and in the rhombencephalon. Intralesional protozoans were histologically detected in five horses, while a positive immunostaining for S. neurona was observed in eleven cases (11/13). Through molecular techniques, six positive cases for the ITS-1 gene were detected, and obtained sequences presented highest similarity with S. neurona. EPM due to S. neurona infection represents an important neurologic disease of horses in Brazil and this disease should be considered as a main differential diagnosis in horses presenting neurologic signs.

Severe outbreak of avian encephalomyelitis in laying hens in Northeastern Brazil

This paper describes the epidemiological, clinical and pathological aspects of an avian encephalomyelitis (AE) outbreak in commercial laying hens in Northeastern Brazil. The disease affected 23,409 layers (from day one until 100 weeks) leading to mortality of 16.5% (5,049/30,600) of the flock. Twenty laying hens were clinically examined, and blood samples were collected and tested by Enzyme-Linked Immunosorbent Assay (ELISA). Five laying hens with neurological signs were necropsied and samples of the brain, cerebellum, spinal cord, sciatic nerve, heart, ceca tonsils, proventriculus and liver were collected, fixed in formalin buffered solution and processed according to routine methods for histological examination. Clinical signs were observed in approximately 60% of the chicken flock and included depression, ataxia, head and neck tremors, head tilt, motor incoordination and corneal opacity and of lens. All laying hens presented seroconversion for AE, with a geometric mean titer (GMT) of 6,854 and CV of 9.6%. At necropsy, there were bilateral opacity of the cornea and lens and the blood vessels of the cerebral cortex were hyperemic. The main microscopic lesions in the central nervous system consisted of red and shrunken neurons in the cerebral cortex, cerebellum and spinal cord. Significant areas of gliosis were observed in the cerebral cortex and in the molecular layer of the cerebellum. Hyperplasia of the proventricular lymphoid tissue and the ceca tonsils were observed with different degrees of intensity. In Northeastern Brazil, there haven’t been previous reports of AE in commercial laying hens and this outbreak possibly occurred by inefficient immunization of laying breeders at the genetic supply company.

Low prevalence of infection by Sarcocystis neurona in horses from the State of Alagoas, Brazil / Baixa prevalência da infecção por Sarcocystis neurona em cavalos do estado de Alagoas, Brasil

The aim of this study was to determine the prevalence of infection by Sarcocystis neurona in horses and identify potential risk factors. Were analyzed 427 samples from 36 farms in 21 municipalities in the Alagoas State, Brazil. Presence of anti-S. neurona antibodies was diagnosed by indirect immunofluorescence antibody test (IFAT) and was confirmed using the immunoblot test. Risk factors were assessed through investigative questionnaires on animal management on the farms. The prevalence of anti-S.neurona antibodies was 2.8% (confidence interval, CI: 1.5-4.9%) from IFAT and 1.6% (CI:0.8-3.34%) from immunoblot, and there were positive horses on 16.6% of the studied farms. None of the variables studied presented associations with serological status for S. neurona. This is the first report on infection by S. neurona in horses reared in Alagoas, Brazil showing a low exposure to S. neurona in this region, but with significant numbers of foci.(AU)

Objetivou-se neste estudo determinar a prevalência e os fatores de risco associados à infecção por Sarcocystis neurona em equinos. Foram analisadas 427 amostras de 36 propriedades localizadas em 21 municípios do estado de Alagoas. O diagnóstico de anticorpos anti-S. neurona foi realizado pela técnica de Imunofluorescência Indireta (IFI) e confirmada por immunoblot. O estudo dos fatores de risco foi realizado a partir de questionários investigativos sobre o manejo dos animais nas propriedades. A prevalência de anticorpos anti-S. neurona foi de 2,8% (I.C. 1,5-4,9%) na IFI e de 1,6% (I.C. 0,8-3,34%) no immunoblot com equinos positivos em 16,6% das propriedades estudadas. Nenhuma variável estudada apresentou associação com o status sorológico para S. neurona. Este é o primeiro relato da infecção por S. neurona em equinos criados no Estado de Alagoas, Brasil, confirmando que os animais desta região têm baixa exposição a S. neurona, mas com significativo número de focos.(AU)

Severe outbreak of avian encephalomyelitis in laying hens in Northeastern Brazil

This paper describes the epidemiological, clinical and pathological aspects of an avian encephalomyelitis (AE) outbreak in commercial laying hens in Northeastern Brazil. The disease affected 23,409 layers (from day one until 100 weeks) leading to mortality of 16.5% (5,049/30,600) of the flock. Twenty laying hens were clinically examined, and blood samples were collected and tested by Enzyme-Linked Immunosorbent Assay (ELISA). Five laying hens with neurological signs were necropsied and samples of the brain, cerebellum, spinal cord, sciatic nerve, heart, ceca tonsils, proventriculus and liver were collected, fixed in formalin buffered solution and processed according to routine methods for histological examination. Clinical signs were observed in approximately 60% of the chicken flock and included depression, ataxia, head and neck tremors, head tilt, motor incoordination and corneal opacity and of lens. All laying hens presented seroconversion for AE, with a geometric mean titer (GMT) of 6,854 and CV of 9.6%. At necropsy, there were bilateral opacity of the cornea and lens and the blood vessels of the cerebral cortex were hyperemic. The main microscopic lesions in the central nervous system consisted of red and shrunken neurons in the cerebral cortex, cerebellum and spinal cord. Significant areas of gliosis were observed in the cerebral cortex and in the molecular layer of the cerebellum. Hyperplasia of the proventricular lymphoid tissue and the ceca tonsils were observed with different degrees of intensity. In Northeastern Brazil, there havent been previous reports of AE in commercial laying hens and this outbreak possibly occurred by inefficient immunization of laying breeders at the genetic supply company.(AU)

Prevalence of antibodies to Sarcocystis neurona and Neospora hughesi in horses from Mexico.

Equine protozoal myeloencephalitis (EPM) is a debilitating disease of horses caused by Sarcocystis neurona and Neospora hughesi. Sera from 495 horses in Durango State, Mexico were tested for anti-protozoal antibodies using enzyme-linked immunosorbent assays (ELISAs) based on major surface antigens of these two parasites. Antibodies to S. neurona were detected in 240 (48.5%) of the 495 horse sera tested with the rSnSAG2/4/3 trivalent ELISA. Multivariate analysis showed that exposure to S. neurona was associated with age, feeding grains and crops, and small herd size. Antibodies to N. hughesi were found in 15 (3.0%) of the 495 horse sera tested with the rNhSAG1 ELISA and confirmed by Western blot of N. hughesi tachyzoite antigen. This is the first report of S. neurona and N. hughesi exposure in horses in Mexico, and it affirms that EPM should be in the differential diagnosis for horses exhibiting signs of neurologic disease in this country.

Diagnosis of Porcine teschovirus encephalomyelitis in the Republic of Haiti.

In February and March 2009, approximately 1,500 backyard pigs of variable age became sick, and approximately 700 of them died or were euthanized in the Lower Artibonite Valley and the Lower Plateau of the Republic of Haiti. The main clinical sign was posterior ataxia followed by paresis and/or paralysis on the second or third day of illness. No gross lesions were observed at postmortem examinations. The morbidity and mortality were approximately 60% and 40%, respectively. Diagnostic samples (whole blood, brain, tonsil, lymph nodes, spleen, and lung) were negative for Classical swine fever virus and African swine fever virus. Porcine teschovirus type 1 was detected by reverse transcription polymerase chain reactions in brain samples. Results of virus isolation, electron microscopy of virus particles, histopathological analysis on brain tissues, nucleic acid sequencing, and phylogenetic analysis of the viral isolate supported the diagnosis of teschovirus encephalomyelitis. The outbreak of the disease in Haiti is the first appearance of the severe form of teschovirus encephalomyelitis in the Americas. This disease poses a potential threat to the swine industries in other Caribbean countries, as well as to Central and North American countries.

Differential astrocyte response to Theiler's murine encephalomyelitis virus infection.

OBJECTIVES: We aimed to address if selective astrocyte apoptosis is involved in the lack of murine demyelinating disease following infection by the L*-1 variant of Theiler's virus. In addition, we investigated whether L*-1-infected astrocytes were able to selectively express molecules whose effects would play a role as pathogenic factors. METHODS: Murine cultured astrocytes were infected with two Theiler viruses, the DA strain and the mutated DA variant L*-1, which does not synthesize the out of frame L* protein. RESULTS: Neither DA nor L*-1 provoked apoptosis, although they replicated in astrocytes inducing GFAP and iNOS expression, as well as subsequent nitric oxide production. In addition, both viruses caused an enhanced expression of ICAM-1, VCAM-1 and decay accelerating factor (DAF). In this connection, values of VCAM-1 and DAF induced by L*-1 were higher and lower, respectively, than those induced by DA. CONCLUSIONS: Since no apoptosis was found, such mechanism would not be involved in the lack of TMEV-induced demyelinating disease by L*-1. In contrast, selective expression of VCAM-1 and DAF molecules induced by L*-1 could have a role in virus clearance from the central nervous system.

A local outbreak of paralytic rabies in Surinam children.

A rapidly fatal encephalomyelitis, which was in most cases characterized by ascending paralysis, developed in seven children of the age of 3 to 10 years in a bushnegro village in the interior of Surinam. Rabies virus was recovered from the central nervous system of three autopsied children. Although the source of infection has not been detected, there is an indication that, at least in some cases, the disease has been transmitted by rat-bite rather than by vampire bats. During the same period a few cases of minor febrile illness occurred in the same community. Since virological and serological evidence of a wide-spread distribution of Coxsackie A virus type 4 was obtained, the latter illness may presumably be attributed to this virus.

St. Louis encephalomyelitis in Hermosillo, Sonora, Mexico.

This report, which describes an epidemic of St. Louis encephalitis in northwestern Mexico, was prompted by the apparent infrequency of previous Mexican outbreaks of this disease. The site of the epidemic was the Municipality of Hermosillo in the State of Sonora. This municipality, with a population of about 273,000, is situated in a hot flat area which is naturally dry but which is also well-irrigated. Here, over an eithy-week period, 51 persons became ill and were hospitalized with symptoms including fever, vomiting, stiff neck, lethargy, and increased cell/protein levels in their cerebrospinal fluid. Sera from 12 of these patients were tested for SLE antibodies by hemagglutination inhibition, complement fixation, and neutralization. The results of these tests were positive and showed a fairly high degree of correlation. In addition, paired serum samples showed a significant rise in SLE antibody titers. Over half of the cases occurred in the City of Hermosillo, the municipal seat; the remainder occurred in 13 outlying areas, most of them quite nearby. Virtually all of the city dwellers affected were residents of low-income districts. The rate of hospital cases was roughly 19 per 100,000 inhabitants, and the case-fatality rate among these cases was approximately 20 per cent. The ratio of male to female patients was 1.3 to 1; sixty-nine per cent of the patients were under 16 years of age.