Conference abstract

Lyssavirus surveillance in dogs in south-east Nigeria: application of molecular and immunological assays

Pan African Medical Journal - Conference Proceedings. 2019:10(11).12 Dec 2019.
doi: 10.11604/pamj-cp.2019.10.11.820

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Keywords: DFA, dRIT, lyssavirus, RT-qPCR
Poster

Lyssavirus surveillance in dogs in south-east Nigeria: application of molecular and immunological assays

Ukamaka Eze11,&, Andre Coetzer2,3, Terence Scott2,3, Boniface Anene1, Romanus Ezeokonkwo4, Chika Nwosuh5, Louis Nel2,3, Claude Sabeta6,7,

1Department of Veterinary Medicine, Faculty of Veterinary Medicine, University of Nigeria, Nigeria, 2Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, South Africa, 3Global Alliance for Rabies Control SA NPC, South Africa, 4Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Nigeria, Nigeria, 5National Veterinary Research Institute, Vom, Plateau State, Nigeria, 6Agricultural Research Council-Onderstepoort Veterinary Institute, OIE Rabies Reference Laboratory, South Africa, 7Department of Veterinary Tropical Diseases, University of Pretoria, South Africa

&Corresponding author
Ukamaka Eze, Department of Veterinary Medicine, Faculty of Veterinary Medicine, University of Nigeria, Nigeria

Abstract

Introduction: the direct fluorescent antibody test (DFA) is the standard method for the diagnosis of both animal and human rabies. This test detects lyssavirus antigen on infected tissues, including nerves and salivary glands. In this study, we compared the molecular quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) and immunologic direct rapid immunohistochemical test (dRIT) with the DFA.

Methods: a total of 278 specimens were tested using DFA. A first group of 260 brain and salivary gland tissue specimens were collected from dog markets in South East Nigeria from October 2015 to July 2016. The second group comprised 18 brain specimens were collected from rabies-suspect dogs at both veterinary hospitals and dog markets. Subsequently, DFA positive brain samples (n = 10) and 10 salivary gland samples associated with DFA positive brain tissues, alongside 18 samples from rabies-suspect dogs (n = 28) were subjected to DFA, dRIT and RT-qPCR.

Results: among the first group, 10 brain and 7 salivary gland samples were DFA positive. Some 82.1% (n = 23), 100% (n = 28) and 96.4% (n = 27) were positive for lyssavirus antigen, respectively. Among the 10 salivary gland samples tested, 70% (n = 7), 90% (n = 9) and 20% (n = 2) were positive for DFA, dRIT and RT-qPCR, respectively. The dRIT and RT-qPCR gave similar results. This shows that dRIT is a highly sensitive diagnostic test for rabies diagnosis and appeared superior to the DFA.

Conclusion: the difference in DFA and dRIT results may highlight laboratory challenges in rabies diagnosis and the possibility of under-reporting in Africa since many laboratories operate within resource-limited settings.