Diagnostic difficulties in human rabies: A case report and review of the literature

Abstract

Rabies is a zoonotic disease with the highest fatality rate of any infectious disease. The clinical features of rabies encephalopathy are highly nonspecific at the onset and clinicians from low endemic areas usually face difficulties in recognizing cases during the early stages. The need for establishing a rapid and accurate test to identify rabies during the ante-mortem period is important. However, in actual clinical practice, the latter may remain difficult for various reasons. In human rabies, positively identifying the antigen, antibody or genetic material by various diagnostic methods during the symptomatic period is affected by the unpredictable nature of viremia, levels of antibody immune response of the host, and the virulence of the infecting strain. Also, more advanced testing with greater sensitivity may not be readily available at all centers. Here we describe a case of a young male who was bitten by a rabid dog and developed progressive encephalopathy with a fatal outcome, with negative antibodies in the cerebrospinal fluid (CSF). A review of the literature on the clinical features, diagnostic tests, treatment and prevention of rabies is also presented.

Antemortem diagnosis of human rabies: A case report

“…In the Arabian Peninsula, RABV is enzootic with human cases of RABV, which has been reported previously in Qatar 9 . The vaccination status of the host, proximity of the bite to the brain, the inoculum size, and the virulence of RABV strain are the major determinants of the incubation period which varies from days to years 5 .…”

Rabies, a Vaccine Preventable Disease: Current Status, Epidemiology, Pathogenesis, Prevention and Control With Special Reference to India

“…There are no diagnostic tests available to diagnose rabies in humans during pre-clinical phase, and till the rabiespathognomonic signs like hydrophobia or aerophobia are developed, the clinical diagnosis might be difficult (Chacko et al, 2016). Several tests are required for diagnosis of rabies antemortem in humans due to the variability of the virus in different samples, the timing of collection of sample, and the antibody response of the host.…”

“…Clinical samples like saliva, serum, spinal fluid, and skin biopsies of hair follicles at the neck region can be included for diagnostic tests (Warrell & Warrell, 2004). Conventional RT-PCR, Real-time PCR, Direct dot-blot enzyme immunoassay (EIA) on saliva and Polymerase chain reaction (RThnPCR) on skin biopsy (non-neural) are available with variable sensitivity and 100% specificity Nagaraj et al, 2006;Dacheux et al, 2008;Chacko et al, 2016). Saliva is a sample of choice for virus isolation as well as reverse transcription polymerase chain reaction (RT-PCR).…”

Using the LN34 Pan-Lyssavirus Real-Time RT-PCR Assay for Rabies Diagnosis and Rapid Genetic Typing from Formalin-Fixed Human Brain Tissue

“…Human rabies infection starts with a prodromal flu-like illness, which is difficult to diagnose due to the non-specific nature of the symptoms; this phase is followed by encephalitic or paralytic manifestations at which time it is easier to recognize or suspect rabies [8][9][10]. Clinical diagnosis of rabies may be challenging if the treating physician lacks experience or there is no patient history of an animal bite; these factors can lead to inadvertently omitting rabies from the differential diagnosis [11,12]. In countries with limited resources, human rabies cases are believed to be underreported.…”