Medium-term cryopreservation of rabies virus samples

Aguiar, Tereza D'ávila de Freitas; Teixeira, Maria Fátima da Silva; Costa, Edmara Chaves; Vitaliano, Allan Bezerra; Teles, Carlos Henrique de Andrade; Barroso, Igor Ciríaco; Dias, Ronaldo Pereira; Moraes, Nélio Batista de

doi:10.1590/0037-8682-0135-2013

Cited by 6 publications

(4 citation statements)

References 18 publications

(20 reference statements)

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“…This is because of the reduction in visible interfering background staining and the reduced reliance upon stringently calibrated equipment. Furthermore, archival samples are subject to degradation, resulting in a larger proportion of background fluorescence when using the DFA test (Aguiar et al 2013 ; Lopes, Venditti & Queiroz 2010 ; Rojas Anaya et al 2006 ). On the contrary, the DRIT does not rely on fluorescence and thus largely eliminates any potential misinterpretations of results because of the limited interfering background staining caused by degraded or archival samples.…”

Section: Discussionmentioning

confidence: 99%

Enhanced diagnosis of rabies and molecular evidence for the transboundary spread of the disease in Mozambique

Coetzer

Anahory²,

Dias³

et al. 2017

J. S. Afr. Vet. Assoc.

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Rabies is a neglected zoonotic disease with veterinary and public health significance, particularly in Africa and Asia. The current knowledge of the epidemiology of rabies in Mozambique is limited because of inadequate sample submission, constrained diagnostic capabilities and a lack of molecular epidemiological research. We wanted to consider the direct, rapid immunohistochemical test (DRIT) as an alternative to the direct fluorescent antibody (DFA) for rabies diagnosis at the diagnostic laboratory of the Central Veterinary Laboratory (CVL), Directorate of Animal Science, Maputo, Mozambique. Towards this aim, as a training exercise at the World Organisation for Animal Health (OIE) Rabies Reference Laboratory in South Africa, we performed the DRIT on 29 rabies samples from across Mozambique. With the use of the DRIT, we found 15 of the 29 samples (52%) to be negative. The DRIT-negative samples were retested by DFA at the OIE Rabies Reference Laboratory, as well as with an established real-time Polymerase chain reaction, confirming the DRIT-negative results. The DRIT-positive results (14/29) were retested with the DFA and subsequently amplified, sequenced and subjected to phylogenetic analyses, confirming the presence of rabies RNA. Molecular epidemiological analyses that included viruses from neighbouring countries suggested that rabies cycles within Mozambique might be implicated in multiple instances of cross-border transmission. In this regard, our study has provided new insights that should be helpful in informing the next steps required to better diagnose, control and hopefully eliminate rabies in Mozambique.

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Section: Discussionmentioning

confidence: 99%

Enhanced diagnosis of rabies and molecular evidence for the transboundary spread of the disease in Mozambique

Coetzer

Anahory²,

Dias³

et al. 2017

J. S. Afr. Vet. Assoc.

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“…The most common possible reasons for incongruent results, viz. antigen degradation/putrefaction and the misinterpretation of fluorescence when performing the DFA test, were all considered [ 12 , 26 , 27 , 28 , 29 , 30 ]. However, sample degradation should be discussed in more detail.…”

Section: Discussionmentioning

confidence: 99%

Epidemiology of Rabies in Lesotho: The Importance of Routine Surveillance and Virus Characterization

et al. 2017

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Rabies is widespread throughout Africa and Asia, despite the fact that the control and elimination of this disease has been proven to be feasible. Lesotho, a small landlocked country surrounded by South Africa, has been known to be endemic for rabies since the 1980s but the epidemiology of the disease remains poorly understood due to limited sample submission, constrained diagnostic capabilities, and a lack of molecular epidemiological data. Considering the existing challenges experienced in Lesotho, we aimed to evaluate the direct, rapid immunohistochemical test (DRIT) as an alternative to the direct fluorescent antibody (DFA) test for rabies diagnosis in Lesotho. Towards this aim, extensive training on the implementation and interpretation of the DRIT was hosted in Lesotho in April 2016 before both tests were applied to all samples subjected to routine rabies diagnosis at the Central Veterinary Laboratory (CVL). We found agreement between the DFA and DRIT assays in 90/96 samples (93.75%). The samples that produced inconsistent results (n = 6) were re-tested a further two times with both assays before being subjected to a real-time qPCR to confirm the diagnosis. Additionally, a statistically significant three-fold increase in the average number of samples submitted per month was observed after the DRIT implementation started, following continuous rabies awareness initiatives amongst the animal health professionals in the country over a 12-month period (p = 0.0279). Partial G-L intergenic regions of selected rabies-positive samples (n = 21) were amplified, sequenced, and subjected to phylogenetic analyses. Molecular epidemiological analyses, which included viruses from neighbouring provinces in South Africa, suggested that at least three independent rabies cycles within Lesotho were implicated in instances of cross-border transmission. This study has evaluated alternative methods for diagnosing and improving rabies surveillance in Lesotho, as well as providing new information that would be of importance in the planning of future disease intervention campaigns, not only in Lesotho, but also in neighbouring South Africa.

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“…Furthermore, archival samples are subject to degradation, resulting in a larger proportion of background fluorescence when using the DFAT. 16,30,31 On the contrary, the DRIT does not rely on fluorescence and thus largely eliminates any potential misinterpretations…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Direct Rapid Immunohistochemistry Test (DRIT) for Postmortem Diagnosis of Rabies

Chhabra¹

2017

JCD

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Direct fluorescent antibody test (DFAT) is considered as the gold standard for diagnosis of rabies in infected mammals as it has high sensitivity and specificity. However, high cost and technical demand limits its utilization, particularly in developing countries including India. Therefore, in this study we evaluated recently developed direct rapid immunohistochemistry test (DRIT) for diagnosis of rabies in comparison with the DFAT. A total of 109 brain samples received during the period of 6 years from different regions of India were tested following standard protocol. The results showed 100% correlation between the two tests.

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Medium-term cryopreservation of rabies virus samples

Cited by 6 publications

References 18 publications

Enhanced diagnosis of rabies and molecular evidence for the transboundary spread of the disease in Mozambique

Enhanced diagnosis of rabies and molecular evidence for the transboundary spread of the disease in Mozambique

Epidemiology of Rabies in Lesotho: The Importance of Routine Surveillance and Virus Characterization

Evaluation of Direct Rapid Immunohistochemistry Test (DRIT) for Postmortem Diagnosis of Rabies

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