Retrospective study of Bovine herpesvirus 5 meningoencephalitis in cattle from São Paulo State, Brazil

Bovine herpesvirus meningoencephalitis in the State of Tocantins, Brazil

Three outbreaks of herpesvirus meningoencephalitis in cattle have been reported in three municipalities in the northern region of the State of Tocantins, Brazil. In one outbreak, 41 predominantly young bovines were affected, with 2-3 deaths in some cases. The animals showed neurological signs of incoordination, blindness, and recumbency, with death occurring within approximately 4-5 d. At necropsy, hyperemia and leptomeningeal hemorrhages were observed in the brain. Histology revealed more intense lesions in the rostral portions of the brain, mainly affecting the frontoparietal cerebral cortex, with nonsuppurative encephalitis and meningitis, glial nodules, neuronophagia, and eosinophilic intranuclear inclusion bodies in the astrocytes and neurons. This study shows the presence of bovine herpesvirus in Tocantins, probably the highly neurotropic type 5 strain, and emphasizes its importance in the differential diagnosis of bovine neuropathies.

Antiviral activity of 4-oxoquinoline-3-carboxamide derivatives against bovine herpesvirus type 5

BACKGROUND

Bovine herpesvirus type 5 is an important agent of meningoencephalitis in cattle and has been identified in outbreaks of bovine neurological disease in several Brazilian states. In recent years, oxoquinoline derivatives have become an important focus in antiviral drug research.

METHODS

The cytotoxicity and anti BoHV-5RJ42/01 activity of a set of synthetic 4-oxoquinoline derivatives 4a-k were assayed on Madin-Darby Bovine Kidney cell and antiviral activity by plaque reduction assay.

RESULTS

The most promising substance (4h) exhibited CC₅₀ and EC₅₀ values of 1,239 µM ±5.5 and 6.0 µM ±1.5, respectively, with an SI =206. Two other compounds 4j (CC₅₀ = 35 µM ±2 and EC₅₀ = 24 µM ±7.0) and 4k (CC₅₀= 55 µM ±2 and EC₅₀ = 24 µM ±5.1) presented similar inhibitory profile and selectivity indexes of 1.4 and 2.9, respectively. The results of the time-of-addition studies revealed expressive reduction of virus production (≥80%) in different stages of virus replication cycle except for compound 4h that slightly inhibited virus yield in the first 2 h post infection, but it showed expressive virus inhibition after this time.

CONCLUSIONS

All three compounds slightly interact with the virus on the virucidal assay and they are not able to block virus attachment and penetration. Antiviral effect of oxoquinoline 4h was more prominent than acyclovir which leads us to suggest compound 4h as a promising molecule for further anti-BoHV-5 drug design.

Cattle diseases in Mato Grosso do Sul, Brazil: a 24-year survey (1995-2018)

ABSTRACT: We reviewed the records of 5,083 cattle necropsies performed from January 1995 to December 2018 and filed at the Laboratory of Anatomic Pathology (LAP) of the “Universidade Federal de Mato Grosso do Sul” (UFMS). These necropsies were performed either by LAP-UFMS faculty (22.33%) or by field veterinary practitioners (77.67%) who subsequently submitted material for histological evaluation at the LAP-UFMS. Conclusive diagnoses were reached in 46.21% of the protocols (2,349 cases), and approximately 65% of the cases were classified as inflammatory or parasitic diseases, with rabies being the most diagnosed disease (20.82% of total conclusive diagnosis). There were a large number of protocols in which the diagnosis was of nonsuppurative meningoencephalitis of unknown cause (NSMUC). Those were the main differentials for rabies and bovine herpesvirus-5 necrotizing meningoencephalitis (NME); that is, the number of rabies cases may be even higher if one considers that many cases of NSMUC might be undiagnosed rabies cases. Toxic and toxic-infectious diseases were the second most prevalent category, and botulism cases represented 41% of this category. The other categories corresponded to less than 20% of the total diagnoses and were distributed in decreasing order of frequency as degenerative diseases (9.79%), diseases caused by physical agents (3.87%), other diseases (2.13%), neoplasms and tumor-like lesions (1.79%), metabolic or nutritional disorders (1.75%) and congenital malformations (0.64%). The large number of inconclusive diagnoses was mainly due to improper conditions of mailed-in material for histopathological evaluation, namely, nonrepresentative samples of all organs, autolysis, and the absence of epidemiological and clinical-pathological information.