Concept of communicable diseases
Disease: is the deviation of body from normal health.
Health: is the state of complete physical, mental and social wellbeing of an individual and not merely the absence of disease or infection (WHO).
Communicable
That which can be transmitted from one person to another directly or indirectly
Signs
What you observe from the patient
Symptom
What the patient tells you
Infection
Is the invasion of human body by microbes causing unfavourable health illness or diseases.
Incidence
That rate at which a disease occurs or attacks. (Number of new and old cases of a disease in a community)
Prevalence
The number of person sick or portraying a certain condition in a stated population at a particular time (Number of new and old cases)
Incubation Period
The time interval that elapse between exposure to an infectious agent and the appearance of the first signs and symptoms.
Endemic
A disease that habitually exist in a locality
Epidemic
A disease outbreak which simultaneously affecting people in an area at a time (an outbreak of disease)
Pandemic
A disease that spread to several countries and affect a large number of people
Sporadic
Usually an epidemic occurs in isolated cases and its apparently connected with any epidemic
Contact
Direct or indirect exposure to an infection
Transmission
Pass on to or communicated directly or indirectly
Carrier
Is an infected person or animal that harbours a specific infectious agent
Healthy Carrier
Is an infected person or animal that harbours specific infectious agent in the absence of clinical signs and symptoms
Diagnosis
The method by which we can arrive at the cause. The nature signs and symptoms of a disease
Host
The organic structure upon which parasite or bacteria thrive
Reservoir
Is the place of usual growth and multiplication of an infective organism
Source
The person, animal, object or substance from which an infectious agent passes immediately to a host
Control
The ability to reduce to a minimum the presence of a disease condition
Resistance
The sum total of the body mechanism, which interpose barriers to the progress of invasion or multiplication of an infectious agent
Immunity
Is the ability of the body to resist infection
Antibodies
Is specific form of blood protein produced in the lymphoid tissue and able to counteract the effect of bacteria antigens or toxins
Surveillance
Is the system of constant monitoring of all aspect of the occurrence and spread of a disease
Quarantine
Is the period of isolation of an infection or suspected case to prevent the spread of the disease
Isolation
Is a separation for a special consideration, control of observation or some part or group of person or animals from other to facilitate control of communicable disease
Convalescent
Recovering from a disease
Notification
Is the official reporting of occurrence of a specified disease to a designated health authority
Vaccination
Is the act of inoculation or injecting antigenic materials for the purpose of producing active artificial immunity
Immunization
Is the administration of antigens to induce immunity
Epidemiology
Is the study of all factors and its inter relationship of a disease with man
Vector
Is a living organism that transmit a disease agent
Infectious agent
Is a living organism that lives in the body of another (parasite) and multiplies all at the expense or and detriment of the host. It maybe virus, bacteria, fungi, rickettsia or metazoan.
TYPES OF HOSTS
Normal host: this is a host in which the parasite develop normal and live up to adult stage e.g. man for Ascaris lumbricoides
Abnormal host: is a host that does not support the development of parasite to the adult stage (Larva of tape worm in man)
Intermediate host: this is the host that harbours only the larva stage (immediate) of parasite e.g. Taenia solium in pigs and Taenia saginata in cattle
Definitive host: is the host that harbours sexually mature (adult) parasite e.g. Taenia solium in man
Reservoir host: is the host that allows normal growth of parasite up to the adult stage; the host does not show any signs of infection (healthy carrier) example Bush pigs for trypanosome
Susceptible host: is a person or animal that does not possess resistance against a particular pathogenic micro-organism