Infectious Diseases - Most Frequently Reported Diseases

In 2001 the three most frequently reported infectious diseases in the United States were chlamydia (783,242 cases—the highest it has been since voluntary reporting began in the mid 1980s), gonorrhea (361,705 cases), and acquired immune deficiency syndrome (AIDS; 41,868 cases), all sexually transmitted diseases. The remaining notifiable infectious diseases in the top 10 were as follows:

• Salmonellosis—a foodborne disease causing fever and intestinal disorders (40,495 cases)
• Syphilis, all stages—a sexually transmitted disease that occurs in three stages; it can be congenital (an infant can be born with the disease) (32,221 cases)
• Varicella (chicken pox)—a disease (usually of childhood) marked by a vesicular rash on the face and body caused by the herpes varicella zoster virus (22,536 cases)
• Shigellosis—foodborne and waterborne dysentery (20,221 cases)
• Lyme disease—a disease spread by ticks (17,029 cases)
• Tuberculosis—an airborne disease that usually affects the lungs but also can affect the bones and other organs (15,989 cases)
• Hepatitis A—a foodborne and waterborne disease causing inflammation of the liver (10,609 cases)

Table 7.2 shows the number of cases of these and other notifiable diseases reported to the CDC each month in 2001.

TABLE 7.1
Infectious diseases designated as notifiable at the national level, 2001

Acquired immunodeficiency syndrome (AIDS)	Haemophilus influenzae, invasive disease	Rabies, human
Anthrax	Hansen disease (leprosy)	Rocky Mountain spotted fever
Botulism	Hantavirus pulmonary syndrome	Rubella
Brucellosis	Hemolytic uremic syndrome, postdiarrheal	Rubella, congenital syndrome
Chancroid	Hepatitis A, acute	Salmonellosis
Chlamydia trachomatis, genital infection	Hepatitis B, acute	Shigellosis
Cholera	Hepatitis B, perinatal	Streptococcal disease, invasive, group A
Coccidioidomycosis	Hepatitis C; non-A, non-B	Streptococcal toxic-shock syndrome
Cryptosporidiosis	Human immunodeficiency virus (HIV) infection, adult	Streptococcus pneumoniae, invasive, drug-resistant
Cyclosporiasis	HIV infection, pediatric (13 yrs)	Streptococcus pneumoniae, invasive, <5 yrs
Diphtheria	Legionellosis	Syphilis
Ehrlichiosis, human granulocytic	Lyme disease	Syphilis, congenital
Ehrlichiosis, human monocytic	Malaria	Tetanus
Ehrlichiosis, human, other or unspecified agent	Measles	Toxic-shock syndrome
Encephalitis, California serogroup viral	Mumps	Trichinosis
Encephalitis, eastern equine	Pertussis	Tuberculosis
Encephalitis, St. Louis	Plague	Tularemia
Encephalitis, western equine	Poliomyelitis, paralytic	Typhoid fever
Escherichia coli, enterohemorrhagic (EHEC), O157:H7	Psittacosis	Varicella (chickenpox)*
EHEC, serogroup non-O157	Q fever	Varicella deaths
EHEC, not serogrouped	Rabies, animal	Yellow fever
Gonorrhea
* Although varicella (chickenpox) is not a nationally notifiable disease, the Council of State and Territorial Epidemiologists recommends reporting cases of this disease to Centers for Disease Control.
SOURCE: "Infectious Diseases Designated as Notifiable at the National Level during 2001," in "Summary of Notifiable Diseases, United States, 2001," Morbidity and Mortality Weekly Report, vol. 50, no. 53, May 2, 2003

Resistant Strains of Bacteria

Antibiotics generally have been considered "miracle drugs" that control or cure many bacterial infectious diseases. However, in the last decade almost all major bacterial infections in the world are becoming increasingly resistant to the most commonly prescribed antibiotic treatments mainly because of repeated and improper uses of antibiotics, according to the CDC. Decreasing inappropriate antibiotic use is the best way to control this resistance.

Bacteria such as pneumococcus, which causes pneumonia and children's ear infections—diseases long considered common and treatable—are evolving into strains that are proving to be untreatable with commonly used antibiotics. Pneumococcal bacteria cause many hundreds of thousands of cases of pneumonia, bacterial meningitis (inflammation of the tissue covering the brain and spinal cord), and almost half of the more than twenty-five million annual visits to American pediatricians for otitis media (middle ear infections). Since the 1980s, national rates of penicillin resistance have soared from less than 5 percent of patients treated to more than 30 percent of patients treated in 1996.

Between February and June 1997, 1,047 strains of pneumococcus obtained from thirty-four hospitals in the United States and Canada were tested for susceptibility to nineteen antibiotics. Among the 845 U.S. samples, only 56 percent were fully susceptible to penicillin, another 28 percent were moderately susceptible, and 16 percent were fully resistant.

To treat patients with penicillin-resistant pneumococcus infections, physicians use a combination of other antibiotics, such as vancomycin, imipenem, and rifampin for resistant pneumonia and clindamycin or cefuroxime for ear infections. One of the national health goals for 2010 is to achieve 90 percent coverage of non-institutionalized adults aged sixty-five years and older for both influenza and pneumococcal vaccinations. In 2000 the U.S. Advisory Committee on Immunization Practices added adults aged fifty to sixty-four years to the universal recommendations for influenza vaccination. Many public health professionals are advocating widespread use of the pneumococcal vaccine in the hope that it will produce "herd immunity"—when a large proportion of the population is immune, the likelihood of person-to-person spread is so small that the disease does not proliferate and even nonimmune individuals are protected from disease.

Increase in Escherichia Coli Infection Caused by Antibiotics

On July 25, 2002, a study funded by the National Institutes of Health (NIH) reported increasing rates of Escherichia coli (E. coli) infection attributable to antibiotic use among premature infants. The study, published in the New England Journal of Medicine (vol. 347, no. 4), looked at the medical records of more than 5,000 babies born throughout the United States and found that E. coli infection rates had more than doubled from three per 1,000 births to seven per 1,000 births. E. coli and group B streptococci are bacteria that frequently exist in the gastrointestinal tract and cause no medical problems. If, however, they are passed at birth from a pregnant mother to

TABLE 7.2
Reported cases of notifiable diseases, by month, 2001

Disease1	Total	Jan.	Feb.	Mar.	Apr.	May	June	July	Aug.	Sept.	Oct.	Nov.	Dec.
AIDS2	41,868	2,550	2,949	3,275	2,886	3,482	3,759	3,406	3,217	3,696	3,507	4,369	4,772
Anthrax	23	—	—	—	—	—	1	—	—	3	11	7	1
Botulism, foodborne	39	—	4	—	2	2	2	1	9	13	—	—	6
Infant	97	3	5	15	8	10	7	7	7	9	9	6	11
Other (includes wound)	19	—	—	2	2	—	2	1	5	1	—	2	4
Brucellosis	136	5	4	15	5	12	19	7	17	14	11	7	20
Chancroid3	38	—	—	9	—	—	12	—	—	7	—	—	10
Chlamydia3,4	783,242	—	—	187,864	—	—	190,115	—	—	197,521	—	—	207,742
Cholera	3	—	—	—	1	1	—	1	—	—	—	—	—
Coccidioidomycosis5	3,922	89	242	200	162	63	303	218	258	361	398	336	1,292
Cryptosporidiosis	3,785	116	134	189	146	145	232	289	860	827	302	274	271
Cyclosporiasis5	147	1	15	4	8	5	20	14	29	23	15	7	6
Diphtheria	2	—	—	—	—	1	—	—	—	1	—	—	—
Ehrlichiosis, human granulocytic	261	1	1	16	—	4	15	43	46	40	6	14	75
Human monocytic	142	3	1	3	2	6	21	24	16	15	8	7	36
Encephalitis, California
serogroup viral	128	—	—	—	—	1	1	11	19	40	28	12	16
Eastern equine	9	—	—	—	—	—	—	—	4	2	2	—	1
St. Louis	79	—	—	—	—	—	—	—	40	33	3	—	3
Escherichia coli enterohemorrhagic (EHEC)
O157:H7	3,287	56	89	103	115	170	354	362	487	627	339	240	345
EHEC, serogroup non-O157	171	5	2	8	6	8	10	13	33	20	18	20	28
EHEC, not serogrouped	20	1	—	2	—	1	—	1	2	4	4	2	3
Gonorrhea3	361,705	—	—	86,379	—	—	83,831	—	—	95,705	—	—	95,790
Haemophilus influenzae,
invasive disease	1,597	110	125	169	133	121	178	87	96	100	80	108	290
Hansen disease (leprosy)	79	3	5	9	4	6	10	7	2	4	7	5	17
Hantavirus pulmonary syndrome	8	1	—	2	1	—	1	—	—	1	1	—	1
Hemolytic uremic syndrome, postdiarrheal	202	6	6	6	8	10	17	20	16	34	25	15	39
Hepatitis A	10,609	653	742	864	652	639	859	769	951	1,301	935	910	1,334
Hepatitis B	7,843	361	476	751	541	558	713	580	632	749	563	614	1,305
Hepatitis C; non-A, non-B	3,976	304	352	403	338	287	410	277	313	359	282	224	427
Legionellosis	1,168	42	61	77	71	56	114	111	94	152	110	99	181
Listeriosis	613	26	40	34	42	49	51	62	63	71	51	56	68
Lyme disease	17,029	174	430	379	284	549	1,965	2,870	2,882	2,165	1,280	935	3,116
Malaria	1,544	90	104	96	74	112	137	182	163	210	82	84	210
Measles	116	12	18	25	5	11	8	6	11	7	3	8	2
Meningococcal disease	2,333	225	292	302	249	170	209	118	102	139	130	124	273
Mumps	266	13	13	21	27	23	19	16	32	16	21	19	46
Pertussis	7,580	341	443	563	350	348	461	359	445	637	512	612	2,509
Plague	2	—	—	—	—	—	2	—	—	—	—	—	—
Psittacosis	25	1	—	2	1	—	3	1	1	1	3	7	5
Q fever5	26	—	—	2	—	2	3	7	1	5	1	1	4
Rabies, animal	7,150	423	431	733	624	548	691	508	676	853	547	475	641
Rabies, human	1	—	—	—	—	—	—	1	—	—	—	—	—
Rocky Mountain spotted fever	695	4	6	9	15	32	88	110	83	99	66	40	143
Rubella	23	—	—	5	1	2	6	1	1	3	2	—	2

TABLE 7.2
Reported cases of notifiable diseases, by month, 2001

Disease1	Total	Jan.	Feb.	Mar.	Apr.	May	June	July	Aug.	Sept.	Oct.	Nov.	Dec.
Rubella, congenital syndrome	3	—	—	—	—	—	—	—	—	—	—	—	3
Salmonellosis	40,495	1,566	1,748	2,327	2,406	2,632	4,210	4,251	4,646	5,666	3,639	3,016	4,388
Shigellosis	20,221	891	913	1,216	986	1,206	2,008	1,959	2,405	2,384	1,905	1,608	2,740
Streptococcal disease, invasive, group A	3,750	269	324	466	433	294	366	291	190	236	216	212	453
Streptococcal toxic-shock syndrome	77	8	9	7	9	7	11	1	5	3	3	4	10
Streptococcus pneumoniae, invasive, drug-resistant5	2,896	224	338	396	303	218	212	127	116	128	87	134	613
Streptococcus pneumoniae, invasive, <5 years5	498	64	61	61	59	45	24	15	17	26	45	40	41
Syphilis, total (all stages)3	32,221	—	—	7,152	—	—	8,256	—	—	8,399	—	—	8,414
Congenital (age <1 yr)3	441	—	—	119	—	—	113	—	—	123	—	—	86
Primary and secondary3	6,103	—	—	1,335	—	—	1,488	—	—	1,609	—	—	1,671
Tetanus	37	4	1	1	5	3	8	1	3	——	2	9
Toxic-shock syndrome	127	5	13	25	6	9	6	11	6	9	7	10	20
Trichinosis	22	2	1	1	1	—	3	3	1	6	3	—	1
Tuberculosis6	15,989	563	881	1,233	1,200	1,336	1,461	1,228	1,398	1,290	1,384	1,304	2,711
Tularemia	129	1	1	3	6	5	28	22	23	18	10	6	6
Typhoid fever	368	9	22	29	19	38	34	30	39	48	32	21	47
Varicella (chickenpox)	22,536	1,385	1,689	2,472	2,505	1,811	1,475	283	1,345	683	1,623	1,843	5,422
1No cases of western equine encephalitis, paralytic poliomyelitis, or yellow fever were reported in 2001.
2Total number of acquired immunodeficiency syndrome (AIDS) cases reported to the Division of HIV/AIDS Prevention—Surveillance and Epidemiology, National Center for HIV, STD, and TB Prevention (NCHSTP), through December 31, 2001.
3Totals reported quarterly to the Division of Sexually Transmitted Diseases Prevention, NCHSTP, as of May 3, 2002.
4Chlamydia refers to genital infections caused by C. trachomatis.
5Notifiable in 40 states.
6Totals reported to the Division of Tuberculosis Elimination, NCHSTP, as of March 29, 2002.
SOURCE: "Table 1. Reported Cases of Notifiable Diseases, by Month—United States, 2001," in "Summary of Notifiable Diseases, United States, 2001," Morbidity and Mortality Weekly Report, vol. 50, no. 53, May 2, 2003

her unborn child, then the infant's immune system may be unable to effectively combat the infection.

The study found that rates of group B strep infection among infants decreased by almost 75 percent during the 1990s, probably in response to increasing use of antibiotics during labor and delivery (the birthing process) to prevent mother-to-infant spread of the infection. The antibiotic most often used was amoxicillin, a drug that combats strep but does not harm E. coli. As a direct result of the effort to reduce strep infections, E. coli infections increased. The researchers observed that E. coli had surpassed group B strep as the most commonly occurring infection among premature infants. This finding is considered troubling because E. coli infection is potentially more dangerous than strep infection.

EDUCATING PHYSICIANS AND PATIENTS ABOUT APPROPRIATE USE OF ANTIBIOTICS.

According to the CDC, antibiotic resistance is among the most urgent public health problems in the world. In 1995 the CDC Division of Bacterial and Mycotic Diseases began a national campaign to reduce antimicrobial resistance by encouraging appropriate use of antibiotics. In 1999 the CDC worked with several medical professional societies to develop educational programs for medical students, physicians, and patients. In a published statement, Dr. Richard Besser, medical director of the CDC's National Campaign for Appropriate Antibiotic Use, called for physician and public support to tackle the problem. Dr. Besser asserted:

The biggest problem is inappropriate prescribing of antibiotics. Up to 40 percent of antibiotics prescribed in doctors' offices are for viral infections, which are not treatable with antibiotics. There are many reasons for this, including demand from patients, time pressure on physicians, and diagnostic uncertainty. The patient wants to get back to work or get their child back to school, and the doctor wants the patient to feel satisfied with treatment. The result is over-prescribing of antibiotics, resulting in the development of resistant bacteria. The best way to combat this practice is to educate the physicians and the public to decrease both demand and over-prescribing. In addition, providing clinicians with better means of diagnosing respiratory infections may remove some of the uncertainty that promotes over-prescribing.

In February 2004 the CDC reported that pressure from the parent makes a difference to the pediatrician's prescribing method. One study showed that doctors prescribe antibiotics 65 percent of the time if they feel that parents expect them, but only 12 percent of the time if they feel parents do not expect them. This emphasizes the need for public awareness and understanding of the need to take part in preventing antibiotic resistance. Consequences of failure of antibiotics to treat formerly treatable illnesses could be dire: longer-lasting illnesses, more doctor visits or longer hospital stays, the need for more expensive and toxic medications, and even death.