EU case definitions

Case definition

European Union (EU) case definitions provide standardised criteria for identifying and reporting communicable diseases to ECDC. These definitions only apply to surveillance at the EU/EEA level and ensure that every case in every Member State is classified similarly, which is essential for accurate and consistent disease surveillance across borders.

These definitions are set out in the Commission Implementing Decision (EU) 2018/945, which lists the diseases and health issues under EU surveillance.

However, for some diseases, especially emerging threats such as COVID-19 or mpox, the EU legislation has not been updated yet, and ECDC, therefore, uses its own operational case definitions. These are tailored to effectively respond to new public health challenges and are regularly updated to reflect the latest scientific knowledge and surveillance needs.

Diseases

Anthrax

Avian influenza in humans

Botulism

Brucellosis

Campylobacteriosis

Chikungunya virus disease

Chlamydia infections

Cholera

(COVID-19)

Creutzfeldt-Jakob disease, variant (vCJD)

Cryptosporidiosis

Dengue

Diphtheria

Echinococcosis

Giardiasis

Gonorrhoea

Hepatitis A

Hepatitis B

Hepatitis C

HIV infection and AIDS

Infections with haemophilus influenza group B

Influenza including Influenza A(H1N1)

Invasive meningococcal disease

Invasive pneumococcal disease

Legionnaires’ disease

Leptospirosis

Listeriosis

Lyme neuroborreliosis

Malaria

Measles

Meningococcal disease, invasive

Mpox

Mumps

Pertussis

Plague

Pneumoccocal invasive diseases

Poliomyelitis

Q fever

Rabies

Rubella

Rubella, congenital

Salmonellosis

Severe Acute Respiratory Syndrome (SARS)

Shiga toxin /verocytotoxin -producing Escherichia coli (STEC/VTEC)

Shigellosis

Smallpox

Syphilis

Syphilis, congenital

Tetanus

Tick-borne encephalitis

Toxoplasmosis, congenital

Trichinellosis

Tuberculosis 

Tularaemia

Typhoid and paratyphoid fevers

Viral haemorrhagic fevers 

West Nile virus infection

Yellow fever

Yersinosis

Zika virus disease

Zika virus disease, congenital

Special health issues 

 
Disclaimer: The terminology used in the list above is based on the terminology used in the case definitions. Hence, the terminology may differ from the one in the Commission Implementing Decision on the communicable diseases and related special health issues to be covered by epidemiological surveillance – Annex 1 (replacing Commission Decision No 2000/96/EC).

Page last updated 26 Aug 2025