STD (Sexually Transmitted Diseases) Reports
December 2006

Monthly STD Report − December 2006
St. Charles County Department of Community Health and the Environment
Kristy Baumgart, MPH

For the month of December, St. Charles County had 66 laboratory confirmed STD cases (as of 1/22/07), which is lower than 2005 (n = 31) and slightly higher than 2004 December totals (n = 61). December 2006 and 2004 closely mirror each other. This subtle increase may be due to the growing population of St. Charles County. Using the 2005 census information as the total population (n= 329,940) of St. Charles County, the incidence rate for STDs during December 2006 is 20.0 cases/100,000 and for 2005 was 9.4. Because the 2006 population estimates have not been released, the actual incident rate for 2006 may be lower than 20. Using the 2004 population estimate (320,734), the county experienced an incident rate of 19.0 cases/100,000 during the month of December. The graph below shows the number of diagnoses for each STD during the month of December in 2004, 2005, and 2006.

STD Counts for the Month of December
St. Charles County Department of Community Health and the Environment, 2004-2006

The yearly counts and incident rates for STD cases are listed in the table below. As you can see, the total number of cases for 2006 was higher than the previous two years, but the actual incident rate was very comparable to the previous year, which may be an exaggeration since the same population (329,940) was used as the denominator. Once the 2006 population estimate is released, the 2006 rates will be readjusted.

The actual counts reveal that the number of gonorrhea cases in 2006 was higher than previously recorded. Because of this jump, the total number of STD cases for 2006 was higher.

	2006	2005	2004
Chlamydia Count Rate/100,000	521 157.9	545 165.1	504 157.1
Gonorrhea Count Rate/100,000	152 46.1	102 30.9	84 26.2
Syphilis (All Phases) Count Rate/100,000	4 1.2	4 1.2	3 0.94
Totals Count Rate/100.000	677 205.2	656 198.8	594 185.2

The chart below compares monthly STD case totals from 2004−2006. December 2006 was fairly typical for STD cases in St. Charles County. This graph is intended to show the seasonality of STDs in St. Charles County. A better way to show this data would be to plot the STD rates; however, the most current population information we have is from 2005, and would not show the increase in population from year to year. This population growth would likely cause the rates to appear lower for 2006.



The following chart shows the 2006 rate of STD cases per zip code per 100,000 people, using the 2000 population estimates for each zip code. The rates most likely are inflated due to the current 2006 population estimate for each each zip code. For instance, the 63367 zip code has the highest rate (1520 per 100,000 people); however, this zip code has experienced rapid growth since the 2000 census.

Zip Code	Number of STD Cases	Population	Rate/100,000
63301	159	46059	345.2
63303	88	41575	211.7
63304	44	38586	114.0
63332	3	1207	248.5
63341	4	3154	126.8
63348	8	4526	176.8
63366	117	57519	203.4
63367	127	8350	1520
63376	128	68970	185.6
63385	33	13931	236.9
unknown	65	unknown	unknown

To examine the effects of whether the number of cases per zip code fluctuates with diagnosis month, the following graph was established:



There doesn't appear to be a clear pattern on the relationship between diagnosis month and zip code of residence. At first glance, it appears that the 63301 and 63303 zip codes do experience some fluctuation during the summer months; however comparing previous years may prove a better comparison.



As noted by the chart below, females clearly outnumber the number of males with lab-confirmed STDs. This gross difference may be due to the fact that females tend to seek treatment and/or get tested for STDs more frequently than males. Tailoring prevention messages to males may be an important tool for future educational programs.



The highest numbers of STD cases have occurred within the young adult population. Steps to improve STD interventions and/or education may need to be addressed. The month of December was very similar to previous months, where the large majority of cases occurred within the 15-24 year olds.