Reporting of Communicable Diseases
Reporting of selected communicable diseases is required within countries, and in some instances reporting is also required internationally to WHO. Reporting usually takes the form of either a case report or infection reports (some countries only require aggregate reporting), or an outbreak or event report.
1. Case reports: Case reporting provides diagnosis, age, sex and date of onset for each person with the disease. Sometimes it includes identifying information, such as the name and address of the person with the disease. Additional information, such as treatment provided and its duration, are required for certain case reports.
National legislation or guidelines often indicate which diseases must be reported, who is responsible for reporting, the format for reporting, and how case reports are to be entered into and forwarded within the national system. If there is a requirement for international case reporting (see below), national governments report to WHO.
2. Outbreak or event reports: Outbreak reporting provides information about an increase in the number of cases above the expected of persons with a communicable disease that may be of public concern. The specific disease causing the outbreak may not be included in the list of diseases officially reportable, or it may be of unknown etiology if it is newly recognized or emerging.
National legislation or guidelines may indicate which types of outbreak must be reported, who is responsible for reporting, the format for reporting, and how case reports are to be entered into and forwarded within the national system. In general, outbreak reporting is required by the most rapid means of communication available. When there is a requirement for outbreak reporting internationally (see below), national governments report to WHO. The diseases listed in CCDM19 are distributed among 5 classes of reporting, referred to by class number throughout the text under section 9B1 of each disease.
Class 1: Case report required internationally to WHO by the International Health Regulations (2005), or as a disease under surveillance by WHO
International Health Regulations (2005)
Diseases under surveillance by WHO
Diseases under surveillance by WHO include:
- Louse-borne typhus fever
- Relapsing fever
- Meningococcal meningitis
- Paralytic poliomyelitis
For both subcategories in Class 1, case report is required to the WHO through the national health authority. Collective outbreak reports including the number of cases and deaths may be requested on a daily or weekly basis for diseases with outbreak potential, such as influenza.
Class 2: Case report regularly required wherever the disease occurs
Diseases of relative urgency require reporting either because identification of contacts is required, or because the source of infection must be known in order to begin control measures.
National health authorities generally require reporting of the first recognized case in an area, or the first case outside the limits of a known affected local area, by the most rapid means available, followed by weekly case reports—examples include diseases under surveillance by WHO (see above), typhoid fever and diphtheria. National health authorities may also require reports of infectious diseases caused by agents that may be used deliberately, such as anthrax or tularemia.
Class 3: Selectively reportable in recognized endemic areas
Many national health authorities do not require case reporting of diseases of this class. Reporting may be required in instances of undue frequency or severity, in order to stimulate control measures or acquire essential epidemiological data. Examples of diseases in this class are scrub typhus, schistosomiasis and fasciolopsiasis.
Class 4: Obligatory report of outbreaks only—no case report required
Many countries require reporting of outbreaks to health authorities by the most rapid means available. Information required often includes number of cases, date of onset, population at risk and apparent mode of spread. Examples are staphylococcal foodborne intoxication and outbreaks of an unidentified etiology.
Class 5: Official report not ordinarily justifiable
Diseases in this class occur sporadically or are uncommon, often not directly transmissible from person to person (chromoblastomycosis), or of an epidemiological nature that offers no practical measures for control (common cold).