The spectrum of infectious diseases is expanding and many infectious diseases once thought to be conquered are increasing.1 Recent events such as a newly discovered Hantavirus p ulmonary syndrome foodborne and waterborne outbreaks caused by Escherichiae coli O157:H7 and Cryptosporidium and the currently growing crisis of antibiotic resistance have demonstrated the emergence and reemergence of infectious diseases. Th e causes for this resurgence are many and complex and include microbial adaptation and change; changes in human demographics and behavior; changes in the environment; the increases in national and international travel; changes in food handling shipping an d processing; and breakdowns in public health measures for previously controlled infections (e.g, cholera, tuberculosis [TB], pertussis).1

In addition, overall deaths due to infectious diseases are increasing. In the United States the crude death rate due to infectious diseases as the underlying cause- of-death increased 58 percent from 1980 through 1992.2 As Figure 1 shows, age-adjusted mortality increased 39 percent during the same period.2 While acquired immunodeficiency syndrome (HIV/AIDS) accounted for many of these deaths others invol ved long-recognized killers such as TB and pneumonia.

To address the challenges of emerging infectious disease threats, the Centers for Disease Control and Prevention (CDC) in partnership with state and local health departments, other federal agencies, academic institutions, health care providers, interna tional and public service organizations, has developed a strategic plan, Addressing Emerging Infectious Disease Threats: A Prevention Strategy for the United States.1 Published in 1994, the plan emphasizes th e improvement and expansion of infectious disease surveillance; applied research; prevention and control activities; and also proposes to strengthen the public health laboratory infrastructure.1 The implementation o f this plan would result, among other things, in investigations needed to more accurately monitor trends in infectious disease morbidity and mortality.2 In this report we evaluated trends in infectious disease morta lity for Missouri residents and compared these results with recent documented national trends that show that infectious disease mortality for the United States has been increasing.

The current disease classification system, International Classification of Diseases, 9th Revision (ICD-9), does not readily allow assessment of the aggregate burden of infectious diseases.2 Although IC D-9 contains a set of codes (001-139)3 labeled as infectious diseases, this grouping leaves out many infectious diseases. The ICD-9 places many infectious diseases in non-infectious categories (such as the classific ation of endocarditis among cardiovascular diseases and the classification of meningitis and middle ear infections among diseases of the nervous system and sense organs, respectively).1 Fewer than half of deaths dir ectly attributable to infectious diseases are labeled explicitly as infectious in this classification system.2 Therefore, to assess more accurately the overall burden of infectious disease mortality for Missouri res idents, a recoding scheme developed by CDC classifying ICD-9 codes as infectious diseases, consequence of infectious diseases, or not infectious diseases was used. This recoding scheme categorized an additional 377 ICD-9 codes as either infectious disease s or consequences of infections. This recoding scheme was used in the national study and was obtained from the National Technical Information Services (order number PB96-500194).2

For Missouri residents, the age-adjusted death rate due to infectious diseases as the underlying cause-of-death increased approximately 28 percent (from 41.6 to 53.2 deaths per 100,000) between 1980 and 1992 (Figure 1). In comparison, the infectious di sease age-adjusted mortality for US residents increased 39 percent for the same time period (Figure 1).2 Deaths due to respiratory tract infections, septicemia and HIV/AIDS account for most of this increase for Miss ouri (Figure 2) and the U.S. In Missouri, between 1980 and 1992, the death rate due to respiratory tract infections increased 19.2 percent, from 31.2 to 37.2 deaths per 100,000. The death rate from septicemia increased 89.8 percent, from 4.2 to 8.0 deaths per 100,000 for the same time period. HIV/AIDS deaths increased from none in 1980 to 8.8 per 100,000 in 1992.

The infectious disease death rate is increasing at the fastest rate for ages 25 to 44, for Missouri and the U.S. primarily because of HIV/AIDS. Between 1980 to 1992, the rate for this age group increased five fold from 5.6 to 28.3 deaths per 100,000 for Missouri residents (Figure 3). For the U.S., the comparable rate increased from 6 to 38 deaths per 100,000 for the same time period.2

Infectious disease death rates increased in both sexes, from 1980 to 1992, with infectious disease mortality among males higher than among females in practically each age group for Missouri and the US.

For Missouri residents, the infectious disease death rate in whites increased about 24.3 percent (from 40.3 to 50.1 deaths per 100,000) from 1980 to 1992 (Figure 4). For African Americans, the infectious disease death rate increased approximately 46.2 percent (from 57.1 to 83.5 deaths per 100,000) for the same time period (Figure 4). For the U.S., the 1992 infectious disease death rate among African Americans was 88 per 100,000; 36 percent higher than for the population as a whole.2

Results 1992 to 1995

For Missouri residents, between 1992 and 1995, the age- adjusted death rate due to infectious diseases as the underlying cause-of-death increased an additional 10.3 percent (from 53.2 to 58.7 deaths per 100,000). In 1995, infectious diseas es were the underlying cause-of-death for 4,045 (7.5 percent) of the 54,222 Missouri resident deaths.