1. You are working in a Health Center which serves a population of 14,500 people. In the period from January to March you treat a total of 126 new cases of upper respiratory infection, and from April to June you treat a total of 70 new cases of respiratory infection. a. Calculate the incidence of upper respiratory infection in January-March. and April-June.
b. What may be some of the reasons that there is a change in the incidence?
c. Why are we measuring incidence rather than prevalence in this example?

2. In this same health center that serves a population of 14,500 people, you treat a number of people with asthma and with diabetes (Type II). Since they all come to the center for their medicines at least once in two months, you count all the persons with asthma and all those with diabetes in the months of June and July. You find that during this time, you have treated 45 people with asthma and 165 people with Type II diabetes.
a. Calculate the prevalence of asthma and of diabetes in this population.
b. Why are we measuring prevalence rather than incidence in this example?

3. During an entire year approximately 4,000 people, both adults and children, come to your PHC to receive care. During that entire year, the diagnosis of diarrhea was made in 500 people who came in to be seen for that problem.
a. What was the annual incidence of diarrhea in your PHC clinic population that year?
b. Can you say that was the incidence of diarrhea in the whole village? Why or why not?

4. Among the 4,000 people who come to your PHC for care, one-half of them are adults. Among the adults, 50 of them have chronic arthritis.
a. What is the prevalence of arthritis among the adults who come to your PHC?

5. In the most recent vaccination campaign in your Health Center, a total of 450 children less than 2 years of age received their 4th dose of oral polio vaccine, and 375 children less than 2 year of ages received their 4th dose of DPT vaccine. The total number of children less than the age of 2 in the catchment area of your health center is 600.
a. What is the vaccination ratio for the completed primary series of oral polio vaccine?
b. What is the vaccination ration for the completed primary series of DPT vaccine?
c. Are these ratios good, or can anything be done to improve these ratios?
6. In a particular community, 115 persons in a population of 4400 became ill with food poisoning. These 115 ill persons were from 75 households, and the total number of persons living in these 75 households was 425.
a. What is the ratio of ill people in the community?
b. What is the ratio of ill people in the 75 affected households?