The manner in which a disease behaves in a community is determined by -

Ans. is `D' i.e., All of the above o Disease results from a complex interaction between man, agent and environment. o There are two phases in a disease process ? A) Prepathogenic phase The agent has not yet entered man. But the factors which ours interaction of agent with human are already existing in the environment. That means, man is exposed to the risk of disease. B) Pathogenic phase This phase begins with the entry of the disease agent in the susceptible human host. The disease agent multiplies and induces tissues and physiological changes which results in disease. The disease process has two periods :? i) Incubation period ii)Pathogenic period The behavior of disease is dependent on following factors ? 1) Agent --> Infectivity (infectiousness of disease), virulence and pathogenicity. 2) Host --> Age, Sex, genetic factors, education, socioeconomic status, living habits, nutrition, exercise, alcoholism and smoking etc. Environment --> Standard of hygiene (sanitation), housing (Density of aggregation), water, air, soil, noise, radiation, reservoirs of infection, vectors of disease etc.