Diagnostic tests for human rabies

The lack of reliable data concerning the number of human deaths from rabies presents one of the principal difficulties in a realistic assessment of the importance of this disease, and this lack of an accurate assessment has led to its underestimation and neglect. Priority should therefore be given to establishing a diagnostic test that can confirm human rabies on the basis of biological results. Indeed, only a laboratory diagnosis can properly identify infection, because clinical diagnosis remains difficult to interpret and is insufficiently specific. Historically, diagnosis has been based solely on post-mortem analysis of a cerebral biopsy using immunofluorescence techniques. Although this remains the standard method, considerable progress has been made with the advent of new molecular techniques and the evaluation of new, less-invasive sampling methods that are more easily accepted by the patient's family. Intra-vitam diagnosis of human rabies is now possible using reliable, robust, validated techniques that can be used everywhere, including in regions with limited resources, using minimally invasive or non-invasive sampling (such as saliva or skin biopsies). In practice, one of the major challenges with the diagnosis of human rabies is still the transfer and accessibility of such validated techniques in centralised reference laboratories located in low-income enzootic countries, in order to achieve the biological confirmation of each suspected case of rabies. At the same time, it is necessary to develop easy, fast and low-cost diagnostic methods that can be used in rural and remote areas in peripheral laboratories, or ideally at the patient's bedside.