The clinician or other responsible health care worker should without delay notify the local health authority that a communicable or a peculiar disease exists within the particular jurisdiction. Administrative regulations that describe which communicable diseases are to be reported and how they should be reported may vary greatly from one region to another because of different conditions and different disease frequencies. This manual presents a basic reporting scheme. The purpose of disease reports is to provide necessary and timely information to permit the institution of appropriate investigation and control measures by responsible health authorities. In addition, the reporting scheme encourages uniformity in morbidity and mortality reporting so that data among different health jurisdictions within a country and among nations can be compared.

A reporting system functions at four levels. The first is the collection of the basic data in the local community where the disease occurs. The data are next assembled at district, state or provincial levels. The third stage is the aggregation of the information under national auspices. Finally, for certain prescribed diseases, report is made by the national health authority to the WHO.

Consideration here is limited to the first level of the reporting system the collection of basic data at the local level -- since that is the fundamental part of any reporting scheme and a primary responsibility of local health workers. The basic data sought at the local level are of two kinds (also see Definitions, Report of a disease):

1. Report of Cases: Each local health authority, in conformity with regulations of higher authority, will determine what diseases are to be reported routinely. Procedures should be developed that indicate, who is responsible for reporting, the nature of the report required, and the manner in which reports are forwarded to the next superior jurisdiction.

Physicians or other responsible health care workers are required to report all notifiable illnesses that come to their attention. In addition, the statutes or regulations of many localities require reporting by hospital, householder or other persons having knowledge of a case of a reportable disease. Within hospitals, a specific officer should be charged with the responsibility for submitting required reports. These may he individual case reports or reports of groups of cases (collective reports).

Case reports of a communicable disease provide minimal identifying data of name, address, diagnosis, age, gender and date of report for each patient, and, in some instances, other suspected cases. Dates of onset and basis for diagnosis are also useful. The right of privacy of the individual must be respected at all levels of the health system.

Collective reports are the number of cases, by diagnosis that occur within a prescribed time and without individual identifying data, e.g., "20 cases of malaria, week ending October 6."

2. Report of Epidemics: In addition to individual case reports, any unusual or group expression of lllness that may be of public concern (see Definitions, Epidemic) should be reported to the local health authority by the most expeditious means, whether or not that illness is included in the list of diseases officially reportable in the particular locality, and whether it is a well-known identified disease or an indefinite or unknown clinical entity (see Class 4, below).

The diseases listed in this manual are distributed among five classes (see below), according to the practical benefit that can he derived from reporting.

These classes are referred to by number throughout the text under section 9B1 of each disease. The classification scheme provides a basis on which each health jurisdiction may determine its list of regularly reportable diseases. Case finding can be passive, i.e., the physician initiates the report in compliance with custom or regulation, or stimulated passive, when the health officer regularly contacts the clinicians, climes, or hospitals, to request the desired information. Case finding is active only when the health officer or a staff member of the health department searches the hospital or hospital records to find a current case or cases of a communicable disease.

Class 1: Case Report Universally Required by International Health Regulations or as a Disease under Surveillance by WHO.

This class can be divided into the following types:

1. Those diseases subject to the International Health Regulations (1969), Third Annotated Edition 1983, Updated and Reprinted 1992, WHO, Geneva; i.e., the internationally quarantinable diseases -- plague, cholera, yellow fever. The Regulations are currently under revision and are expected to be distributed to the World Health Assembly in the year 2002. The key notification change expected is the replacement of the current list of three diseases with a requirement to notify WHO of all disease events of "urgent international public health importance." Criteria to help countries identify which events are urgent and international are being developed and tested.

1A. Diseases under Surveillance by WHO, established by the 22d World Health Assembly -- lousebome typhus fever, relapsing fever, paralytic poliomyelitis, malaria and influenza.

An obligatory case report is made to the health authority by telephone, fax, e-mail or other rapid means in an epidemic situation. Collective reports of subsequent cases in a local area on a daily or weekly basis may be requested by the next superior jurisdiction, as for example, in a cholera epidemic. The local health authority forwards the initial report to the next superior jurisdiction by the most expeditious means if it is the first recognized case in the local area or is the first case outside the limits of a local area already reported. Otherwise, reports are submitted weekly by mall or in unusual situations by telephone, fax, or e-mail.

Class 2: Case Report Regularly Required Wherever the Disease Occurs

Two subclasses are recognized based either on the relative urgency for investigation of contacts and source of infection or for starting control measures.

2A. Case report to local health authority by telephone, fax, e-mail or other rapid means. Reports are generally forwarded to next superior jurisdiction weekly by mail -- except that the first recognized case in an area or the first case outside the limits of a known affected local area is reported by telephone fax or e-mail -- examples are typhoid fever and diphtheria. In addition, infectious diseases caused by agents that may be used by bioterrorists (anthrax, plague, tularemia, botulism, suspected smallpox, etc.) should be reported by telephone as soon as any of these diseases are suspected.

2B. Case report by the most practicable means is forwarded to the next superior jurisdiction as a collective report, weekly by mail. Examples are brucellosis and leprosy.

Class 3: Selectively Reportable in Recognized Endemic Areas

In many states and countries, diseases of this class are not reportable. Reporting may be prescribed in particular regions, states or countries by reason of undue frequency or severity. Three subclasses are recognized: 3A and 3 B are useful primarily under conditions of established endemicity as a means to lead toward prompt control measures and to judge the effectiveness of control programs. The main purpose of 3C is to stimulate control measures or to acquire essential epidemiologic data.

3A. Case report by telephone, fax, e-mail or other rapid means in specified areas where the disease ranks in importance with Class 2A. These diseases may not be reportable in many countries. Examples are scrub typhus and arenaviral hemorrhagic fever.

3B. Case report by most practicable means is forwarded to the next superior jurisdiction as a collective report by mail weekly or monthly; not reportable in many countries; examples -- bartonellosis and coccidioidomycosis.

3C. Collective report weekly by mail to local health authority is forwarded to next superior jurisdiction by mall weekly, monthly, quarterly, or sometimes annually. Examples are schistosomiasis and fasciolopsiasis.

Class 4: Obligatory Report of Epidemics -- No Case Report Required

Prompt report of outbreaks of particular public health importance by telephone, fax, e-mail or other rapid means is forwarded to the next superior jurisdiction. Pertinent data include number of cases, time frame, approximate population involved and apparent mode of spread. Examples are staphylococcal foodborne intoxication, adenoviral keratoconjunctivitis, unidentified syndrome.

Class 5: Official Report Not Ordinarily Justifiable

Diseases of this class are of two general kinds: those typically sporadic and uncommon, often not directly transmissible from person to person (chromoblastomycosis); or those of such epidemiologic nature as to offer no special practical measures for control (common cold).

Diseases are often made reportable but the information gathered is put to no practical use, and with no feedback to those who provided the data. This leads to deterioration in the general level of reporting, even for diseases of much importance. Better case reporting results when official reporting is restricted to those diseases for which control services are provided or potential control procedures are under evaluation, or epidemiologic information is needed for a definite purpose.