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

Coetzer, André; Anahory, Iolanda Vieira; Dias, P. T.; Sabeta, Claude; Scott, Terence Peter; Markotter, Wanda; Nel, Louis Hendrik

doi:10.4102/jsava.v88i0.1397

Cited by 14 publications

(19 citation statements)

References 25 publications

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“…Therefore, it will be particularly beneficial if rabies diagnosis is decentralized to include the dRIT testing, enabling every state to perform primary diagnosis before sending the samples to the reference laboratories for confirmatory testing should the need arise. These findings demonstrated that the dRIT is capable of detecting low rabies-positive samples, supporting previous reports that the dRIT assay is not only extremely effective, but also reliable and well-suited to resource-limited settings such as Nigeria where sample conditions will not always be optimal [26,27,31,32,33,52]. Coupled with this, the cost of the routine use of the dRIT makes this assay ideal for decentralized rabies diagnosis in resource-limited settings such as Nigeria.…”

Section: Discussionsupporting

confidence: 83%

“…Another diagnostic test recently recommended by the OIE for confirmatory rabies diagnosis is either a conventional polymerase chain reaction (PCR) or a quantitative real-time PCR (qRT-PCR) that has passed the OIE Standards for validation [22]. While the detection of amplified viral nucleic acid is a highly effective diagnostic principle, resource-limited countries often lack the necessary infrastructure-namely an appropriate cold chain and dedicated PCR rooms to minimize contamination during amplification of specific viral nucleic acids [32,33]. These limitations prevent the implementation of advanced molecular techniques in Nigeria [9,23].…”

Section: Introductionmentioning

confidence: 99%

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Economic and feasibility comparison of the dRIT and DFA for decentralized rabies diagnosis in resource-limited settings: The use of Nigerian dog meat markets as a case study

et al. 2020

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Background Rabies lyssavirus (RABV) is the aetiologic agent of rabies, a disease that is severely underreported in Nigeria as well as elsewhere in Africa and Asia. Despite the role that rabies diagnosis plays towards elucidating the true burden of the disease, Nigeria-a country of 180 million inhabitants-has a limited number of diagnostic facilities. In this study, we sought to investigate two of the World Organization for Animal Health (OIE)-recommended diagnostic assays for rabies-viz; the direct fluorescent antibody test (DFA) and the direct rapid immunohistochemical test (dRIT) in terms of their relative suitability in resource-limited settings. Our primary considerations were (1) the financial feasibility for implementation and (2) the diagnostic efficacy. As a case study, we used suspect rabies samples from dog meat markets in Nigeria.

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Section: Discussionsupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Economic and feasibility comparison of the dRIT and DFA for decentralized rabies diagnosis in resource-limited settings: The use of Nigerian dog meat markets as a case study

et al. 2020

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“…Presently, with the exception of the anti-RV MABs or PABs (which may be self-produced or obtained from the OIE/WHO rabies reference laboratories), all of the other test reagents for the DRIT are available commercially (e.g., distilled water, PBS, TWEEN, formalin, etc.). After a series of incubations, washes and staining, DRIT results are available in ~1 h. Since its original development, the DRIT has been used in Africa, Asia, Europe, the Middle East and the Americas [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Using either MAB or PAB preparations, preliminary sensitivity and specificity values were deemed comparable to the gold standard FAT, with the majority of studies demonstrating complete test agreement, especially when fresh brain samples were tested [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Additional Progress in the Development and Application of a Direct, Rapid Immunohistochemical Test for Rabies Diagnosis

Rupprecht¹,

Xiang

Servat

et al. 2018

Veterinary Sciences

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Laboratory-based surveillance is fundamental to effective rabies prevention and control. The direct fluorescent antibody (AB) test (FAT) is the gold standard for rabies diagnosis. Recently, additional tests besides the FAT have been developed, such as the direct rapid immunohistochemical test (DRIT). In this study, our objective was to further refine technical aspects of the DRIT using a combination of two monoclonal ABs (MABs), 502 and 802, conduct additional testing among rabies reference laboratories using a diversity of animal species and rabies virus (RV) variants and compare the potential utility of the DRIT for end users via proficiency testing (PT) against the FAT. Considering the ideal molar ratios of biotin to AB in formulation of the DRIT conjugate, 3.9 was found to be superior to 7.4, for detection of RV antigens in the brain of a naturally infected raccoon. Optimization of the DRIT conjugate may also be dependent upon the apparent choice of specific viral antigens for testing, as a gray fox RV variant reacted less strongly than a raccoon RV variant in determining the working dilution of the MAB cocktail. Using the same MABs and protocol, the DRIT was compared to the FAT using more than 800 samples of mammalian brains, representative of more than 25 taxa, including in excess of 250 animal rabies cases from Europe and North America. Sensitivity was determined at 98% (96–100%, 95% CI) and specificity was calculated at 95% (92–96%, 95% CI). In a comparison among end users, PT of laboratory personnel resulted in values of 77–100% sensitivity and 86-100% specificity. Based upon these and previously reported results, the DRIT appears to be a suitable alternative to the FAT for use in lyssavirus diagnosis.

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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%

“…Before the routine implementation of the DRIT assay in Lesotho, a workshop on the implementation and interpretation of the assay was presented in April 2016 by a South African diagnostician experienced in the use and interpretation of the assay [ 12 ]. Over the course of the five-day workshop held at the CVL in Maseru, four local diagnosticians were introduced to the DRIT assay and its use in a diagnostic setting by applying the assay blindly to a cohort of archival samples ( n = 57) that had been found to be either rabies-positive or -negative with the gold standard DFA test.…”

Section: Methodsmentioning

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

Cited by 14 publications

References 25 publications

Economic and feasibility comparison of the dRIT and DFA for decentralized rabies diagnosis in resource-limited settings: The use of Nigerian dog meat markets as a case study

Economic and feasibility comparison of the dRIT and DFA for decentralized rabies diagnosis in resource-limited settings: The use of Nigerian dog meat markets as a case study

Additional Progress in the Development and Application of a Direct, Rapid Immunohistochemical Test for Rabies Diagnosis

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

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