Influence of canine brain decomposition on laboratory diagnosis of rabies

Albas, Avelino; Ferrari, Clara Izabel de Lucca; Silva, Luzia Helena Queiroz da; Bernardi, Fernanda; Ito, Fumio

doi:10.1590/s0037-86821999000100004

Cited by 27 publications

(23 citation statements)

References 3 publications

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“…We observed that, after the first week of exposure to room temperature, viral viability promptly diminished, whereas FAT results were positive after 15 days in spite of the loss of the anatomical limits of brain samples. Several authors have noted similar dynamics of both tests during exposure of canine brain samples to 25-29°C, showing a better performance during 6-7 days for FAT and 48 hours for MIT [7,19,20] Higher temperatures drastically reduce the chances of viral detection, and FAT is positive for 72 hours at 37°C [9].…”

Section: Discussionmentioning

confidence: 95%

“…According to the World Health Organization (WHO) recommendations, the RT-PCR technique should not be used for routine post-mortem diagnosis of rabies if brain tissue is available; the direct fluorescent antibody test should be used [3]. However, in decomposed samples, where traditional methods lose their sensitivity, RT-PCR becomes an important diagnostic tool [7,10,11].…”

Section: Discussionmentioning

confidence: 99%

“…High temperatures, such as those recorded in rabiesendemic regions of northern Argentina, cause mild liquefaction to severe decomposition in submitted brain samples. These conditions could cause degradation of the virus structure and production of bacterial toxins that affect the sensitivity of rabies diagnostic tests [7]. If RABV isolates are not preserved at low temperatures (-70°C or lower), they rapidly lose their viability, which has caused the loss of many collections of RABV strains in laboratories that had inadequate infrastructure [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Diagnosis and molecular typing of rabies virus in samples stored in inadequate conditions

Beltrán¹,

Dohmen²,

Pietro

et al. 2014

J Infect Dev Ctries

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Introduction: The exposure of nervous tissue samples to high temperatures affects the sensitivity of rabies virus diagnostic tests, causing degradation of the viral structure. This study evaluated reverse transcriptase polymerase chain reaction (RT-PCR) for the diagnosis and molecular characterization of brain tissue samples in an advanced state of decomposition and poorly conserved viral isolates by comparing it with routine diagnostic tests. Methodology: A panel of three canine brain samples exposed to controlled decomposition for 7, 15, 30, and 120 days were evaluated using fluorescence antibody test (FAT), mouse inoculation test (MIT), and RT-PCR. In addition, 14 isolates of rabies variants, representing the largest circulation in Argentina, preserved in inadequate cooling for six to eight years were analyzed. Molecular typing of strains was performed using a 159-nucleotide region corresponding to the nucleoprotein gene. Results: The three samples analyzed were positive by RT-PCR at all the decomposition times evaluated, in contrast to results observed with FAT and MIT, which rapidly became negative. In addition, 100% of the inadequately preserved samples were characterized molecularly. The limit of detection of RT-PCR was 0.5 MICDL 50 /0.03 mL. Conclusion: RT-PCR can be useful for rabies diagnosis and typing of putrefying samples or rabies isolates stored in inadequate conditions.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diagnosis and molecular typing of rabies virus in samples stored in inadequate conditions

Beltrán¹,

Dohmen²,

Pietro

et al. 2014

J Infect Dev Ctries

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“…The 100% match when comparing our antibody with the commercial one when using DIF in the sensitivity and specificity assays showed that the technique did not suffer any kind of interference, even using CNS samples from different animal species and, although other studies demonstrated that DIF efficacy could be compromised by the loss of sensitivity when the samples analyzed where decomposed (28,29), this did not occur with our conjugate, even in the samples presenting scarce amounts of Negri bodies or high levels of decomposition.…”

Section: Figmentioning

confidence: 79%

First production of fluorescent anti‐ribonucleoproteins conjugate for diagnostic of rabies in Brazil

Caporale¹,

Silva²,

Peixoto³

et al. 2009

Clinical Laboratory Analysis

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The laboratory tests recommended by the World Health Organization for detection of rabies virus and evaluation of specific antibodies are performed with fluorescent antibodies against the virus, the ribonucleoproteins (RNPs), or by monoclonal antibodies. In this study, we purified the rabies virus RNPs for the production of a conjugate presenting sensibility and specificity compatible with commercial reagents. The method employed for the purification of RNPs was ultracentrifugation in cesium chloride gradient, the obtained product being used for immunizing rabbits, from which the hyperimmune sera were collected. The serum used for conjugate production was the one presenting the highest titer (1/2,560) when tested by indirect immunofluorescence. The antibodies were purified by anion exchange chromatography (QAE-Sephadex A-50), conjugated to fluorescein isothiocyanate and separated by gel filtration (Sephadex G-50). The resulting conjugate presented titers of 1/400 and 1/500 when assayed by direct immunofluorescence (DIF) and simplified fluorescence inhibition microtest, respectively. Sensibility and specificity tests were performed by DIF in 100 central nervous system samples of different animal species, presenting 100% matches when compared with the commercial reagent used as standard, independent of the conservation state of the samples. The quality reached by our conjugate will enable the standardization of this reagent for use by the laboratories performing diagnosis of rabies in Brazil, contributing to the intensification of the epidemiological vigilance and research on this disease.

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“…In those cases, polymerase chain reaction (PCR) can provide better results ( 3 ). Since the degree of decomposition at which FAT starts to become ineffective is unknown ( 4 ), when smears from decomposed samples are made for FAT, a suspension of the same brain tissues should be made in the appropriate diluents for the mouse inoculation test (MIT), cell culture, or reverse transcription–polymerase chain reaction (RT-PCR) ( 2 ). However, if all test results are negative, rabies cannot be ruled out because of the condition of the sample.…”

mentioning

confidence: 99%