State's TB cases decline, infection rate remains high A state health official says tuberculosis cases are slowly declining in South Dakota but the infection rate remains high.
"South Dakota does have a high rate of infection but our preventive therapy program has been very successful in keeping those infections from breaking down into active disease," said LaJean Volmer, director of disease prevention for the Department of Health. In 1998, the department started 617 individuals on preventive therapy and reported 23 cases of active tuberculosis (TB), down from 33 in 1988.
Volmer emphasized that there is a difference between TB infection and active TB disease. TB infection results in a positive TB skin test but there are no symptoms of TB and no TB organisms found in the sputum. In contrast, active TB disease is characterized by symptoms and the presence of TB organisms in the sputum. Volmer said TB germs are spread only by those with active disease and that infection is not enough to spread the germ. TB may last for a lifetime as an infection, never developing into disease.
"We do see some fluctuation in TB numbers from year to year but our general trend is downward," said Volmer. "We're also seeing fewer cases among children, another sign the system is working."
Globally, there are over eight million new cases of TB and three million TB deaths each year. Global TB also has a significant impact on the United States, with nearly 40 percent of new TB cases reported in 1997 occurring among foreign-born individuals. In South Dakota, since 1994, the percentage of new TB cases in the state reported among the foreign-born has ranged from a low of 5 percent to a high of 25 percent since 1994.
TB is a bacterial disease usually affecting the lungs, although other parts of the body may also be affected. When a person who has TB disease and is not on medication, coughs or sneezes, the germs get into the air. Prolonged exposure to these germs is normally necessary for infection to occur.