Communicable Diseases Act, B.E. 2558 (2015) · Definitions

Section 4

In this Act:

“communicable disease” means a disease caused by pathogens or toxins from pathogens, which is transmissible to humans, directly or indirectly;

“dangerous communicable disease” means a highly virulent communicable disease which is rapidly transmissible to other persons;

“communicable disease under surveillance” means a communicable disease that requires ongoing monitoring, inspection or data collection;

“epidemic” means a communicable disease or a disease of which the exact cause is unknown, which may be transmitted to other persons rapidly and widely or which has a higher incidence than normally observed;

“carrier” means a human or animal which does not have clinical signs of a communicable disease, but its body gets infected with such disease which may be communicated to other persons;

“contact” means a human who has close contact with humans, animals or physical items infected with a disease to the extent that such disease may be communicated to such person;

“period of communicability” means the period of time in which a pathogen may be transmitted from humans or animals infected with such pathogen to other persons, directly or indirectly;

“isolation” means the separation of a contact or carrier from others in isolated places as to prevent the direct or indirect transmission of pathogens to those who may get infected with such pathogens until the lapse of the period of communicability;

“quarantine” means the restriction of a contact or carrier to isolated places as to prevent the direct or indirect transmission of pathogens to those who may get infected with such pathogens until the lapse of the incubation period or until a carrier status has ended;

“control for observation” means the supervision of a contact or carrier without quarantine, and such contact or carrier may be permitted to transit through any places upon the condition that when reaching any specified locality, such person shall report himself or herself to a local communicable disease control officer for a medical check-up in order to prevent the direct or indirect transmission of pathogens to those who may get infected with such pathogens;

“incubation period” means the period of time from which a pathogen enters a body until the time when the infected person exhibits symptoms of the relevant disease;

“disease infected zone” means any locality or port city outside the Kingdom where a dangerous communicable disease or an epidemic occurs;

“disease investigation” means the procedure to identify causes, sources and reservoirs of diseases for the purpose of disease control;

“surveillance” means observation and data collection and analysis, as well as reporting and following up on the result of disease transmission on an ongoing and systematic basis for the purpose of disease control;

“conveyance” means a vehicle, animal or object used in transporting humans, animals or physical items on land, water or air;

“conveyance owner” includes an agent of the owner, a lessee, an agent of the lessee or an occupier of such conveyance;

“conveyance operator” means a person responsible for the operation of a conveyance;

“traveller” means a person travelling into the Kingdom, and shall include a conveyance operator and crew members of a conveyance;

“immunisation” means a medical action towards humans or animals by any means to develop disease resistance in them;

“isolated place” means any place where a communicable disease control officer has designated as a place for isolation or quarantine of humans or animals which are, or are suspected of being infected with any communicable disease in order to prevent the direct or indirect transmission of such disease to those who may get infected with such disease;

“sanitation” means the control, protection or maintenance of environmental conditions and contributing factors to the occurrence or transmission of communicable diseases;

“port of entry” means any route or place used for entry and exit of travellers, conveyances and physical items internationally, and shall include areas or zones arranged for providing such service;

“Committee” means the National Communicable Disease Committee;

“Provincial Communicable Disease Committee” means a Provincial Communicable Disease Prevention and Control Committee;

“Bangkok Communicable Disease Committee” means the Bangkok Communicable Disease Prevention and Control Committee;

“State agency” means a central official agency, a regional official agency, a local official agency, a State enterprise, a public organisation and other agencies of the State;

“communicable disease control officer” means a person appointed by the Minister to execute this Act;

“Director-General” means the Director-General of Department of Disease Control;

“Minister” means the Minister having charge and control over the execution of this Act.

Unofficial English translation by the Division of Legal Affairs, Department of Disease Control (August 2025); the Thai text prevails.