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close this bookWHO Recommended Surveillance Standards (WHO; 1999; 157 pages)
View the documentAcknowledgements
View the documentAcronyms
View the documentIntroduction
View the documentNational Coordination of Communicable Disease Surveillance
View the documentExplanatory notes
View the documentSurveillance activities: criteria and WHO Department
View the documentCommunicable disease contacts in Regional Offices
close this folderDiseases
View the documentB20-B21-B22-B23-B24 AIDS
View the documentA22 Anthrax
View the documentA23 Brucellosis
View the documentA00 Cholera
View the documentA81.0 Creutzfeldt-Jakob disease
View the documentA90, A91 Dengue fever (A90) including Dengue haemorrhagic fever (DHF) & Dengue shock syndrome (DSS, A91)
View the documentA36 Diphtheria
View the documentB72 Dracunculiasis (Guinea worm disease)
View the documentA98.3, A98.4 Ebola-Marburg viral diseases
View the documentA83.0 Japanese encephalitis
View the documentB74 Lymphatic filariasis
View the documentB96.3 Haemophilus influenzae type b
View the documentB15-B17 Acute viral hepatitis
View the documentB20-B24 HIV infection
View the documentJ10, J11 Influenza
View the documentA96.2 Lassa fever
View the documentA48.1 Legionellosis
View the documentB55.1, B55.2 Cutaneous leishmaniasis
View the documentLeishmania / HIV co-infections
View the documentB55.0 Visceral leishmaniasis
View the documentA30 Leprosy
View the documentA27 Leptospirosis
View the documentB50-54 Malaria
View the documentB05 Measles
View the documentA39 Meningococcal disease
View the documentA87 Viral meningitis
View the documentB73 Onchocerciasis
View the documentA37.0 Pertussis
View the documentA20 Plague
View the documentA36 Poliomyelitis
View the documentA82 Rabies
View the documentA02.0 Salmonellosis
View the documentB65 Schistosomiasis
View the documentA50-52 Syphilis
View the documentA33 Tetanus, neonatal
View the documentB56-0, B56-1 African trypanosomiasis
View the documentB57 American trypanosomiasis
View the documentA15-A19 Tuberculosis
View the documentA75.3 Scrub typhus
View the documentA95.9 Yellow fever
open this folder and view contentsSyndromes
View the documentAnnex 1 Software free and in the public domain
View the documentAnnex 2 Proposed surveillance definitions
View the documentAnnex 3 Role and use of Geographic Information Systems (GIS) and mapping for epidemiological surveillance

A22 Anthrax



Anthrax is a widespread zoonosis transmitted from domestic animals (cattle, sheep, goats, buffaloes, pigs and other) to humans by direct contact or through animal products. Human anthrax is a serious problem in several countries and has potential for explosive outbreaks (especially the gastrointestinal form); while pulmonary (inhalation) anthrax is mainly occupational, the threat of biological warfare attacks should not be forgotten. Anthrax has a serious impact on the trade of animal products.

The control of anthrax is based on its prevention in livestock: programmes based only on prevention in humans are costly and likely to be ineffective except for those industrially exposed. There is an effective vaccine for those occupationally exposed, and successful vaccines for livestock, particularly for herds with ongoing exposure to contaminated soil. In most countries anthrax is a notifiable disease. Surveillance is important to monitor the control programmes and to detect outbreaks.


Clinical description

An illness with acute onset characterized by several clinical forms. These are:

(a) localized form:


cutaneous: skin lesion evolving over 1 to 6 days from a papular through a vesicular stage, to a depressed black eschar invariably accompanied by oedema that may be mild to extensive

(b) systemic forms:


gastro-intestinal: abdominal distress characterized by nausea, vomiting, anorexia and followed by fever

pulmonary (inhalation): brief prodrome resembling acute viral respiratory illness, followed by rapid onset of hypoxia, dyspnoea and high temperature, with X-ray evidence of mediastinal widening

meningeal: acute onset of high fever possibly with convulsions, loss of consciousness, meningeal signs and symptoms; commonly noted in all systemic infections

Laboratory criteria for diagnosis

Laboratory confirmation by one or more of the following:


• Isolation of Bacillus anthracis from a clinical specimen (e.g., blood, lesions, discharges)

• Demonstration of B. anthracis in a clinical specimen by microscopic examination of stained smears (vesicular fluid, blood, cerebrospinal fluid, pleural fluid, stools)

• Positive serology (ELISA, Western blot, toxin detection, chromatographic assay, fluorescent antibody test (FAT))


Note: It may not be possible to demonstrate B. anthracis in clinical specimens if the patient has been treated with antimicrobial agents.

Case classification


Suspected: A case that is compatible with the clinical description and has an epidemiological link to confirmed or suspected animal cases or contaminated animal products.

Probable: A suspected case that has a positive reaction to allergic skin test (in non-vaccinated individuals).

Confirmed: A suspected case that is laboratory-confirmed.


Since the usual ratio of livestock cases to human cases is of the order of 10-20:1, it is ineffective to depend only on human case reports. Routine surveillance must be undertaken, especially in high-risk groups (slaughterhouse workers, shepherds, veterinarians, wool/hide workers), and unexplained sudden livestock deaths must be investigated. Immediate case-based reporting from peripheral level (health care providers or laboratory) to intermediate and central levels of public health sector and to the appropriate level of animal health sector is mandatory. All cases must be investigated.

Routine monthly reporting of aggregated data on confirmed cases and investigation reports from intermediate to central level in public health and animal health sectors.


Case-based data for investigation and reporting


• Case classification by type (suspected/probable/confirmed), and by clinical form (cutaneous/gastro-intestinal/pulmonary (inhalation)/meningeal)

• Unique identifier, age, sex, geographical information, occupation

• Date of onset, date of reporting

• Exposure history

• Outcome

Aggregated data for reporting to central level


• Number of confirmed cases by age, sex, clinical form (cutaneous/gastro-intestinal/pulmonary (inhalation)/meningeal)

• Similarly for livestock by outbreaks and cases in relation to species and appropriate geographic/administrative area


Graphs: Number of suspected/probable/confirmed cases by date.

Tables: Number of suspected/probable/confirmed cases by date, age, sex, geographical area.

Maps: Number of human and animal cases by geographical area.


Surveillance data


• Estimate the magnitude of the problem in humans and animals
• Monitor the distribution and spread of the disease in humans and animals
• Detect outbreaks in humans and animals
• Monitor and evaluate the impact of prevention activities in humans and of control measures in animals

Investigation data


• Identify populations at risk
• Identify potentially contaminated products of animal origin
• Identify potentially contaminated animal sources (herds or flocks)


The surveillance activities of both public health and animal health sectors must be fully coordinated and integrated. Administrative arrangements between the two sectors must be established to facilitate immediate cross-notification of cases/outbreaks, as well as joint case/outbreak investigations. Surveillance and control programmes should be promoted in high-risk areas, such as those with high pH/calcareous soils.


Regional Offices

See Regional Communicable Disease contacts on section "Communicable disease contacts in Regional Offices".

Headquarters: 20 Avenue Appia, CH-1211 Geneva 27, Switzerland

Communicable Diseases Surveillance and Response (CSR)


E-mail: cosivio@who.ch/outbreak@who.ch
Tel: (41 22) 791 2531/4687/2111
Fax: (41 22) 791 4893/0746 attn CSR
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