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.

Genomic characterization of Sebokele virus 1 (SEBV1) reveals a new candidate species among the genus Parechovirus

We determined the genomic features and the taxonomic classification of Sebokele virus 1 (SEBV1), a previously unclassified arbovirus isolated in 1972 from rodents collected in Botambi, Central African Republic. The complete genome sequence was obtained using a deep sequencing approach (Illumina technology) and dedicated bioinformatics workflows for data analysis. Molecular analysis identified SEBV1 as a picornavirus, most closely related to Ljungan viruses of the genus Parechovirus. The genome has a typical Ljungan virus-like organization, including the presence of two unrelated 2A protein motifs. Phylogenetic analysis confirmed that SEBV1 belongs to the parechovirus phylogroup and was most closely related to the Ljungan virus species. However, it appeared clearly distinct from all members of this phylogroup, suggesting that it represents a novel species of the genus Parechovirus.

Fatal case of imported human rabies in Amadora, Portugal, August 2011

We report on a case of imported human rabies in Portugal, in July 2011 in a woman who presented initially complaining of back pain, without relating exposure to animal bites. She had travelled from Portugal to Bissau, Guinea-Bissau, in April where she had been bitten by a dog on 1 May. She was diagnosed with rabies on 26 July and died two weeks later in spite of being treated following the Milwaukee protocol.

Fatal case of imported human rabies in Amadora, Portugal, August 2011

We report on a case of imported human rabies in Portugal, in July 2011 in a woman who presented initially complaining of back pain, without relating exposure to animal bites. She had travelled from Portugal to Bissau, Guinea-Bissau, in April where she had been bitten by a dog on 1 May. She was diagnosed with rabies on 26 July and died two weeks later in spite of being treated following the Milwaukee protocol.

Rabid dog illegally imported to France from Morocco, August 2011

In August 2011, a case of canine rabies was notified to the French veterinary services. The dog was a three-month-old puppy illegally imported from Morocco that presented behavioural changes on 1 August and was admitted to a veterinary clinic on 6 August. It died the following day and the body was shortly sent to the national reference centre where rabies was laboratory-confirmed on 11 August. Contact tracing and post-exposure treatment were initiated immediately.

Rabid dog illegally imported to France from Morocco, August 2011

In August 2011, a case of canine rabies was notified to the French veterinary services. The dog was a three-month-old puppy illegally imported from Morocco that presented behavioural changes on 1 August and was admitted to a veterinary clinic on 6 August. It died the following day and the body was shortly sent to the national reference centre where rabies was laboratory-confirmed on 11 August. Contact tracing and post-exposure treatment were initiated immediately.

Epidemiology of viral encephalitis in 2011

Encephalitis is an inflammation of the brain structures: neurons, vessels or glial cells. However, a consensual definition of the syndrome is difficult to obtain, and it is even more difficult to define encephalitis due a specific agent. Most viruses can be responsible for infectious encephalitis, but the number of encephalitis cases is very limited with regards of the incidence of benign infections from these pathogens. Viruses responsible for encephalitis can be animal-borne, vector-borne or human-to-human transmitted, they can infect preferentially immunocompetent or immunosuppressed patients, and some of them have demonstrated their epidemic potential. Herpes simplex encephalitis is recognized worldwide as the most frequent infectious encephalitis, and the only one with a validated specific treatment. Encephalitis following some viral infections such as measles or rabies can be prevented by vaccination. Unfortunately, effective treatment currently lacks for most encephalitic viral agents identified so far.

[Epidemiologic monitoring of human rabies in an endemic canine rabies area in the Ivory Coast]

AIM

The objective of this study was to analyze the epidemiologic monitoring of human rabies in the rabies medical center of Abidjan.

PATIENT

A cross-sectional study was undertaken based on files of patients having consulted in the rabies center after exposure and suspicion of human rabies between January 2001 and June 2009.

RESULTS

Twenty-six cases of human rabies were reported in 10,706,136 inhabitants (annual incidence of 0.028 cases per 100,000). The number of detected cases increased considerably after reinforcing the monitoring of the disease. Most cases occurred in an urban environment and concerned both sexes. The most concerned age range was under 31 years. The patients' were mostly school children and housewives. In all cases, the rabid animal was a dog and the type of exposure was a bite. Fifty-six percent of the victims had not received any local treatment and almost all no post-exposure prophylaxis. The mean delay before the first symptoms was 49.5 days after exposure and for death, 4 days after the onset of symptoms. Virological diagnosis was made in four cases.

CONCLUSION

In spite of the increase of cases observed since 2006, certainly due to reinforcement of the monitoring network, improvement is needed to assess the real incidence of rabies in the Ivory Coast.

Is there a need for anti-rabies vaccine and immunoglobulins rationing in Europe?

Rabies is a lethal encephalitis caused by a lyssavirus and transmitted from animals to humans via bite wound, scratch wound, or licking of mucous membranes. It is preventable by timely administration of post-exposure prophylaxis (PEP) consisting of four or five doses of rabies vaccine combined, in the most severe cases of exposures, with anti-rabies immunoglobulin (RIG). Although the rabies incidence in humans remains low, rabies is still present in some European countries. Moreover, rabid animals imported from enzootic areas are reported every year in rabies-free areas. These importations threaten the rabies-free status of terrestrial animals in western European countries and challenge the public health surveillance system and the health structures responsible for rabies prophylaxis and control. The importations frequently result in the prescription of a large number of PEP including RIG, especially in western European countries. The situation is inverted in some central and eastern European countries where RIG is underprescribed. Only a limited number of rabies vaccines and particularly of RIG are licensed for use in Europe. Their availability is also limited, a situation that may become worse in the future. It therefore seems important to study the possibility of comparing and unifying national PEP guidelines in Europe, if needed, and to generate effective solutions in the event of a shortage of anti-rabies biological products and RIG in particular, such as rationing these products.

Is there a need for anti-rabies vaccine and immunoglobulins rationing in Europe?

Rabies is a lethal encephalitis caused by a lyssavirus and transmitted from animals to humans via bite wound, scratch wound, or licking of mucous membranes. It is preventable by timely administration of post-exposure prophylaxis (PEP) consisting of four or five doses of rabies vaccine combined, in the most severe cases of exposures, with anti-rabies immunoglobulin (RIG). Although the rabies incidence in humans remains low, rabies is still present in some European countries. Moreover, rabid animals imported from enzootic areas are reported every year in rabies-free areas. These importations threaten the rabies-free status of terrestrial animals in western European countries and challenge the public health surveillance system and the health structures responsible for rabies prophylaxis and control. The importations frequently result in the prescription of a large number of PEP including RIG, especially in western European countries. The situation is inverted in some central and eastern European countries where RIG is underprescribed. Only a limited number of rabies vaccines and particularly of RIG are licensed for use in Europe. Their availability is also limited, a situation that may become worse in the future. It therefore seems important to study the possibility of comparing and unifying national PEP guidelines in Europe, if needed, and to generate effective solutions in the event of a shortage of anti-rabies biological products and RIG in particular, such as rationing these products.

Multicenter comparative study of a new ELISA, PLATELIA™ RABIES II, for the detection and titration of anti-rabies glycoprotein antibodies and comparison with the rapid fluorescent focus inhibition test (RFFIT) on human samples from vaccinated and non-vaccinated people

The envelope glycoprotein G of rabies virus induces the production of neutralising antibodies, which are important in protection against rabies. Therefore, titration of anti-envelope glycoprotein antibodies is a good indicator of the degree of immunity in people during anti-rabies treatment or after vaccination. According to the World Health Organization (WHO) guidelines, a booster vaccine dose should be given if the rabies antibody titre falls below 0.5 IU/ml. Titration of anti-rabies antibodies is also useful for plasma centers in the preparation and standardization of human anti-rabies gamma-globulins for therapeutic use and to a lesser extent for the diagnosis of rabies in human sera and cerebrospinal fluid (CSF). This paper presents a new enzyme-linked immunosorbent assay (ELISA), PLATELIA RABIES II, developed for rabies envelope glycoprotein antibody detection or titration and its comparison to the current reference method (RFFIT). The data collected during validation of the test in a multicenter study are analysed to give a sound overall knowledge of the capabilities of the PLATELIA RABIES II, for instance specificity, linearity, accuracy, precision, detection limit and quantitation limit. To this aim, human serum samples from a total of 1348 vaccinated or non-vaccinated people were tested in parallel using the new ELISA and the RFFIT for the presence of anti-rabies antibodies. Data generated indicate a linear relationship across the range of titration between the two methods. The sensitivity reaches 98.6% and the specificity 99.4%. This study indicates that this new ELISA test is as sensitive and specific as the current standardized reference method. The method is simple, safe, rapid and can be considered as a useful alternative to the neutralisation test.

Rabies in Europe in 2005

Rabies is still present in Europe in 2005. Its incidence in humans remains limited (fewer than 5 human cases per year) through the application of strict prophylactic measures (anti-rabies treatment) and by means of veterinary rabies control measures in the domesticated and wild animal populations. The main indigenous animal reservoirs are: the dog in eastern European countries and on the borders with the Middle East; the fox in central and eastern Europe; the racoon dog in northeastern Europe; and the insectivorous bat throughout the entire territory. Finally, each year, cases of animals with rabies imported from enzootic areas are reported, showing the permeability of borders and traveller's lack of consideration of the rabies risk. These importations constantly threaten the rabies-free status of terrestrial animals in western European countries and complicate the therapeutic decisions taken by physicians in the absence of information regarding the biting animal.

Rabies in Europe in 2005

Rabies is still present in Europe in 2005. Its incidence in humans remains limited (fewer than 5 human cases per year) through the application of strict prophylactic measures (anti-rabies treatment) and by means of veterinary rabies control measures in the domesticated and wild animal populations. The main indigenous animal reservoirs are: the dog in eastern European countries and on the borders with the Middle East; the fox in central and eastern Europe; the racoon dog in northeastern Europe; and the insectivorous bat throughout the entire territory. Finally, each year, cases of animals with rabies imported from enzootic areas are reported, showing the permeability of borders and traveller’s lack of consideration of the rabies risk. These importations constantly threaten the rabies-free status of terrestrial animals in western European countries and complicate the therapeutic decisions taken by physicians in the absence of information regarding the biting animal.