Comparative evaluation of clinicopathological, immunohistochemical, and immunofluorescent techniques for diagnosis of rabies in animals

Beigh, Akeel Bashir; Sandhu, B.S.; Singh, Chanchal; Gupta, Kuldip; Sood, Naresh Kumar

doi:10.1007/s00580-014-2057-9

Cited by 2 publications

(3 citation statements)

References 14 publications

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“…A similar fact had been observed by other authors when evaluating samples of experimentally inoculated mice, which obtained positive results in animals with euthanasia or spontaneous death (Healy et al 2013) and in euthanized cattle for diagnosis (Ribas et al 2013). A critical alternative when the gold standard is not viable or the conventional histopathology with HE and DFAT cannot detect lesions or the viral antigen (Beigh et al 2015), as occurred in this study, in addition to having the advantage of rapid virus inactivation during collection, making transportation and processing safer (Sharma et al 2014).…”

Section: Discussionsupporting

confidence: 72%

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Influence of euthanasia, the intensity of inflammatory lesion and viral load in the laboratory diagnosis of rabies in cattle

Wisser

Fernandes²,

Melchioretto

et al. 2021

Pesq. Vet. Bras.

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This research reports the use of different diagnostic tests in cattle, naturally infected by Rabies lyssavirus (RABV), and correlates the positivity of the tests with the clinical moment of euthanasia, the intensity of the inflammatory lesion and viral load. It also highlights the possibility of euthanasia in early stages of the disease as a way to improve animal welfare. For that, samples of 34 bovine brains were collected for analysis, preserved in 10% buffered formaline and refrigerated with subsequent freezing. The samples were subjected to direct immunofluorescence antibody technique (DFAT) tests, viral isolation in cell culture (VICC), histopathology with hematoxylin and eosin staining (HE), immunohistochemistry (IHC), Shorr stainied neural tissue smears (DSS), Reverse transcription polymerase chain reaction (RT-PCR) and polymerase chain reaction by quantitative reverse transcriptase (qRT-PCR). The areas used for analysis were the cerebellum, parietal telencephalon and thalamus. Samples with Negri bodies (NBs) or immunostaining in at least one of the analyzed areas were considered positive. For the study of the intensity of histological lesions, the lesions were classified into grades 0, 1, 2 and 3 and the positivity of the test in the presence or absence of NBs in one of the three areas analyzed. To verify the influence of the disease clinical evolution, 4-four groups of analysis were created according to the animal’s clinical status at moment of the euthanasia, being: M1 = animal euthanized while standing, M2 = euthanized when in sternal recumbence, M3 = euthanized when in lateral recumbence, M4 = animal with natural death. Of the 34 brains evaluated, IHC was positive in 100% of cases, DFAT was positive in 97.05% of them, and in this negative sample the presence of RABV was confirmed by VICC. NBs ere seen in 88.23% of the cases, and the DSS test was positive in 82.35% of them. All diagnostic techniques showed positive cases in all groups analyzed. Each case was positive in at least two diagnostic methods. All cases that contained NBs were positive for rabies in the other tests. In this study, it was observed that the variables analyzed (intensity of injury and clinical evolution at the moment of euthanasia) had an influence only on HE and DSS techniques, which are based on NB research to form the diagnosis, but did not interfere with the effectiveness of the diagnosis performed by detecting the viral antigen performed by DFAT and IHC. All isolated RABV samples included in the present study have a genetic lineage characteristic of hematophagous bats Desmodus rotundus. The evaluation of qRT-PCR showed that the amount of virus did not interfere in the positivity of the tests. This work shows that IHC and DFAT are safe diagnostic techniques. They are capable of detecting RABV even in euthanized animals in the early stages of clinical evolution with mild intensities of histological lesions.

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Section: Discussionsupporting

confidence: 72%

“…Rabies is an infectious disease of mandatory notification caused by RABV (Rabies lyssavirus), an RNA virus of the Lyssavirus genus that affects the Central Nervous System (CNS) of different species. This almost 100% fatal disease is a widely distributed zoonosis (Buchen-Osmond 2003, Faizee et al 2012, Beigh et al 2015.…”

Section: Introductionmentioning

confidence: 99%

Influence of euthanasia, the intensity of inflammatory lesion and viral load in the laboratory diagnosis of rabies in cattle

Wisser

Fernandes²,

Melchioretto

et al. 2021

Pesq. Vet. Bras.

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“…Rabies is an infectious, notifiable disease that affects the central nervous system (CNS) of several species (Barros et al 2006, Beigh et al 2015, Faizee et al 2012. It causes acute encephalomyelitis in all warm-blooded animals, including humans and many wild species, which can serve as reservoirs for the virus (Rupprecht & Gibbons 2004).…”

Section: Introductionmentioning

confidence: 99%

Cattle rabies: the effect of clinical evolution, viral genetic lineage, and viral load on the severity of histological lesions

Wisser

Neto

Batista³

et al. 2020

Pesq. Vet. Bras.

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ABSTRACT: Our objective was the characterization and staging of histological lesions in different anatomical sites of the central nervous system (CNS) of rabid cattle. The severity of the lesions was compared with the clinical stages of the disease, the variants of viral isolates, and with the load of virus. Thirty-one spontaneously affected rabid cattle the state of Santa Catarina underwent clinical follow-up and were eventually necropsied. CNS tissues were sampled and submitted to direct fluorescent antibody technique (DFAT), immunohistochemistry (IHC), routine histopathology with hematoxylin and eosin stain (HE), reverse transcriptase polymerase chain reaction (RT-PCR), and polymerase chain reaction in quantitative reverse transcriptase in real time (qRT-PCR). Affected cattle were allotted in four groups according to their clinical stage when euthanized: G1, euthanized while standing; G2, euthanized when in sternal recumbence; G3, euthanized when in lateral recumbence; and G4, affected cattle with natural death. In order to evaluate the degree of severity of the lesions and the presence of Negri bodies (NBs), the brain was sectioned at 9 sites. Additionally, spinal cord and trigeminal ganglion sections were examined. The intensity of the lesions was graded as either absent, mild, moderate, or marked, and the presence or absence of the NBs was noted. Histological lesions were characterized by lymphocytic and monocytic meningoencephalitis with NBs in 28 cases. In all analyzed groups, intensities of histological lesions ranging from mild to severe were observed. Brain regions with the highest inflammatory lesion intensity were the medulla at the level of obex, followed by the colliculus and thalamus. NBs were observed in a higher percentage in the cerebellum, followed by medulla at the obex level, striatum complex, and frontal telencephalon. The duration of the clinical course of the disease did not influence the intensity of the inflammatory lesion, but it did influence the presence of NBs, with a higher percentage of these inclusions in cattle that died naturally than in euthanized cattle. All isolated rhabdovirus included in this study were genetically compatible with samples from hematophagous bats Desmodus rotundus. The evaluation by qRT-PCR did not demonstrate a correlation between lesion intensity and the amount of virus.

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Comparative evaluation of clinicopathological, immunohistochemical, and immunofluorescent techniques for diagnosis of rabies in animals

Cited by 2 publications

References 14 publications

Influence of euthanasia, the intensity of inflammatory lesion and viral load in the laboratory diagnosis of rabies in cattle

Influence of euthanasia, the intensity of inflammatory lesion and viral load in the laboratory diagnosis of rabies in cattle

Cattle rabies: the effect of clinical evolution, viral genetic lineage, and viral load on the severity of histological lesions

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