RATIONALE FOR SURVEILLANCE
Rabies, present on all continents and endemic in most African and Asian countries, is a fatal zoonotic viral disease, transmitted to humans through contact (mainly bites and scratches) with infected animals both domestic and wild. Over 40 000 human deaths are estimated to occur each year worldwide, most of them in the developing world (mainly in Asia), and an estimated 10 million people receive post-exposure treatment after being exposed to animals suspected of rabies.
• human rabies prevention through well-targeted post exposure treatment and increased availability of modern rabies vaccine
• disease elimination through mass vaccination of dogs and other animal reservoirs
Surveillance of both human and animal rabies is essential to detect high risk areas and outbreaks quickly and to monitor the use of vaccine.
RECOMMENDED CASE DEFINITION
An acute neurological syndrome (encephalitis) dominated by forms of hyperactivity (furious rabies) or paralytic syndromes (dumb rabies) that progresses towards coma and death, usually by respiratory failure, within 7 to 10 days after the first symptom if no intensive care is instituted. Bites or scratches from a suspected animal can usually be traced back in the patient medical history. The incubation period may vary from days to years but usually falls between 30 and 90 days.
Laboratory criteria for diagnosis
One or more of the following
• Detection of rabies viral antigens by direct fluorescent antibody (FA) in clinical specimens, preferably brain tissue (collected post mortem)
• Detection by FA on skin or corneal smear (collected ante mortem)
• FA positive after inoculation of brain tissue, saliva or CSF in cell culture, in mice or in suckling mice
• Detectable rabies-neutralizing antibody titre in the CSF of an unvaccinated person
• Identification of viral antigens by PCR on fixed tissue collected post mortem or in a clinical specimen (brain tissue or skin, cornea or saliva)
• Isolation of rabies virus from clinical specimens and confirmation of rabies viral antigens by direct fluorescent antibody testing
Suspected: A case that is compatible with the clinical description.
Probable: A suspected case plus history of contact with suspected rabid animal.
Confirmed: A suspected case that is laboratory-confirmed.
HUMAN EXPOSURE TO RABIES:
A person who had dose contact (usually a bite or scratch) with a rabies-susceptible animal in (or originating from) a rabies-infected area.
A person who had a close contact (usually a bite or scratch) with a laboratory-confirmed rabid animal.
RECOMMENDED TYPES OF SURVEILLANCE
SURVEILLANCE IN HUMAN POPULATIONS:
Surveillance of human exposure to rabies:
At peripheral level, especially in rabies-infected areas, reports of patients with a history of animal contact (usually a bite/scratch) should be investigated at once; when required, they should be treated as an emergency. Case-based and aggregated data must be sent regularly from peripheral to intermediate and central level.
Surveillance of cases of human rabies:
Immediate reporting of suspected and confirmed cases from peripheral level (by diagnosing physician and laboratory) to intermediate and central level.
Rapid exchange of information with services in charge of animal rabies surveillance and control is required.
Epidemiological investigation of outbreaks: Investigation of all rabies foci, identifying sources of infection as will as humans and animals exposed or possibly exposed.
SURVEILLANCE IN ANIMAL POPULATIONS (EPIZOOTIC CONTROL): Where the disease is endemic or could be reintroduced, surveillance of animal rabies and similar conditions in wild and domestic species most likely to be reservoirs of disease must be undertaken. Surveillance is laboratory-based. Immediate submission of brain specimen of suspected animal for laboratory diagnosis when human exposure occurs. Suspected domestic animals at the origin of human exposure that cannot be killed must be kept under observation for 10 days. Rapid exchange of information between services in charge of human and animal rabies surveillance and control is required.
RECOMMENDED MINIMUM DATA ELEMENTS
HUMAN RABIES EXPOSURE
Case-based data: Unique identifier, name, age, geographical information, date(s) of bite/scratch, geographical information (location) of biting episode(s), category of exposure, local wound treatment, vaccination history, previous serum treatment, current treatment, outcome; details of biting animal, vaccination history, outcome.
Aggregated data: Exposures by geographical information on biting episode, biting animal, outcome in animal and human populations.
SURVEILLANCE OF DEATHS FROM HUMAN RABIES
Unique identifier, name, age, geographical information, date of onset of symptoms, date(s) of bite/scratch, geographical information (location) of biting episode(s), site of bite on the body, nature of bite, local wound treatment, vaccination history, previous serum treatment, hospital, treatment details, outcome, details of biting animal, samples taken, sample results.
RECOMMENDED DATA ANALYSES, PRESENTATION, REPORTS
Number of human rabies deaths and rabies cases in animals (by species), by date of presentation.
Human exposures by location and dates of biting/scratch episode, by animal species at the origin of exposure and by outcome in human and in animal populations.
Cases by geographical area (e.g., district) and dates of biting/scratch episode, type of animal, occupation and outcome.
PRINCIPAL USES OF DATA FOR DECISION-MAKING
• Detect outbreaks in endemic areas and new cases in rabies-free area.
• Determine high risk areas for intervention
• Rationalize the use of vaccine and immunoglobulin
• Evaluate effectiveness of intervention at the level of the animal reservoir and exposed human population
Intersectoral cooperation of medical and veterinary services, community involvement and participation required for targeted response and control in animal reservoir.
See Regional Communicable Disease contacts on section "Communicable disease contacts in Regional Offices".
Headquarters: 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
Communicable Disease Surveillance and Response (CSR)
E-mail: email@example.com /firstname.lastname@example.org
Tel: (41 22) 791 2575/2111
Fax: (41 22) 791 4893 attn CSR