Bureau of Epidemiology
Bureau of Epidemiology May 1998 Utah Department of Health
inside...
Rheumatic Fever in Utah, 1998: When a sore throat isn’t just a sore throat...
Caution: Ticks Ahead Report on Selected Vector-borne Diseases Utah 1990-1997
Monthly Morbidity Summary

 

Rheumatic Fever in Utah, 1998: When a sore throat isn’t just a sore throat...
What’s going on? The Bureau of Epidemiology was recently contacted by physicians at Primary Children’s Medical Center (PCMC) and the University of Utah School of Medicine regarding an increase in the number of rheumatic fever cases being diagnosed, and an increase in the detection of isolates of a specific group A streptococcal (GAS) strain that has been associated with an increased risk of rheumatic fever. This situation has prompted a closer look at rheumatic fever in Utah.

While still a major health problem worldwide, rheumatic fever had nearly disappeared in the United States by the early 1970s. In 1983 there were only 88 reported cases in this country, compared to more than 10,000 in 1961. The reasons for the disappearance are uncertain, but improved living conditions, access to medical care, and the availability of antimicrobials that are effective against GAS infections, are all believed to be at least partially responsible.

After several decades of a decline in cases of acute rheumatic fever in Utah, an unusual increase was noted in early 1985. By the end of 1987, two Salt Lake City hospitals had reported 150 new cases. The incidence of rheumatic fever in Utah declined from the end of 1987 until 1997, but remained higher than the nationally reported incidence (Veasy LG, Tani LY, Hill HR. J.Pediatr 1994; 124:9-16). Beginning in 1997, another unusual increase in the number of cases of rheumatic fever was noted. Forty-two children with rheumatic fever were evaluated at PCMC in 1997, and since the beginning of 1998, more than 30 children with rheumatic fever have been seen.

These unusual increases in Utah’s rheumatic fever incidence have been temporally associated with the isolation of specific GAS strains from the community. An increase in throat culture isolates of two mucoid GAS strains, M type 18 and M type 3, was observed in Utah children from 1985 to mid-1987. Similar strains were rarely identified in the laboratory at PCMC from mid-1987 to 1996; however, from 1997 to the present, mucoid strains of GAS are again being regularly identified. Twenty-three cultures of mucoid GAS collected during 1997 and 1998 were sent to Dr. Edward Kaplan, director of the World Health Streptococcal Reference Laboratory in Minneapolis, Minnesota. Twenty-one of the 23 heavily encapsulated strains were M type 18. [For more detailed information about the 1985-1987 resurgence see: Veasy LG, Wiedmeier SE, Orsmond GS et al. Resurgence of acute rheumatic fever in the intermountain area of the United States. NEJM 1987; 316: 8, 421-427; and, CDC. Acute Rheumatic Fever -- Utah. MMWR 1987; 36: 108-110, 115.}

Please note a change in reporting of rheumatic fever to the Utah Department of Health! Prior to January 1998, cases of rheumatic fever were reported to the Bureau of Chronic Disease Control. They should now be reported to the Bureau of Epidemiology. To expedite the reporting of a suspected case of rheumatic fever, the primary physician or the consulting physician may report the case by telephone to (801)538-6191. (Please do not hesitate to report because you think someone else has already reported the case! If a case is reported twice, we will identify the duplication.) We ask that physicians or other health care providers contact the Bureau of Epidemiology as soon as possible when a new case of rheumatic fever is identified. Investigators will then contact the patient’s health care provider and promote appropriate follow-up care of the patient and their household contacts. For a case to be counted as a confirmed case of rheumatic fever, it must meet the criteria set by the Centers for Disease Control and Prevention (see below). To expedite the case investigation process, please include the criteria used for the diagnosis of rheumatic fever in your report.

What is necessary to diagnose rheumatic fever? The clinical description of rheumatic fever is an inflammatory illness that occurs as a delayed sequela of GAS upper respiratory infection. The case definition for rheumatic fever is as follows:

Major Criteria for diagnosis: carditis, polyarthritis, chorea, subcutaneous nodules, and erythema marginatum;

Minor Criteria for diagnosis: a) previous rheumatic fever or rheumatic heart disease; b)arthralgia; c) fever; d) elevated erythrocyte sedimentation rate, positive C-reactive protein, or leukocytosis; and e) prolonged PR interval on an electrocardiogram.

A case of rheumatic fever is confirmed when there is an illness characterized by two major criteria or one major and two minor criteria (as described in the clinical description), and by supporting evidence of preceding GAS infection. [Comments: Supporting evidence to confirm streptococcal infection includes increased anti-streptolysin-O or other streptococcal antibodies, throat culture positive for GAS, or recent scarlet fever. The absence of supporting evidence of preceding streptococcal infection should make the diagnosis doubtful, except in Sydenham chorea or low-grade carditis when rheumatic fever is first discovered after a long latent period from the antecedent infection. There is no one specific laboratory test for the diagnosis of rheumatic fever.] (Reference: CDC. Case definitions for infectious conditions under public health surveillance. MMWR 1997; 46 (No. RR-10):52-53.)

What should be done with a suspected case of rheumatic fever that does not meet the case definition? We are interested in knowing about these suspected cases even if they do not meet the case definition. Please report them to the Bureau of Epidemiology.

What can be done to prevent rheumatic fever? The proper diagnosis and treatment of GAS upper respiratory infections can prevent cases of rheumatic fever from occurring. When a child is diagnosed with rheumatic fever, the 1997 Red Book (Report of the American Academy of Pediatrics Committee on Infectious Diseases, 24th edition) instructs clinicians to obtain throat cultures from all of their siblings and any other household contacts. Any household contact with a positive culture should be treated with an appropriate course of antibiotics, regardless of whether they are or have recently been symptomatic.

The 1997 Red Book also reminds clinicians that "the throat culture remains the test of choice" for children who are suspected of having GAS pharyngitis (p. 486). Clinical diagnoses are rarely appropriate for a strep throat because it is difficult to accurately distinguish viral from streptococcal pharyngitis. A number of rapid diagnostic tests for GAS pharyngitis (rapid strep tests) are available. However, these vary in their sensitivity. If a rapid strep test produces a negative result, a throat culture should be obtained to make sure the patient does not have GAS pharyngitis. The specificity of rapid strep tests is high, however, and a positive test need not be followed by a throat culture.

The key to successful treatment of GAS pharyngitis is the completion of an appropriate course of antibiotics. Penicillin remains the drug of choice (except in penicillin-allergic individuals), but alternate antibiotics may be prescribed. An appropriate course of antibiotics is also recommended for household contacts of rheumatic fever patients but this may or may not be sufficient to eliminate streptococcal carriage. The table below lists alternate regimens for the treatment of GAS pharyngitis.

Regimen Dose/duration
Penicillin V 250 mg 2-3 times/day PO for 10 days (children) OR 500 mg 2-3 times/day PO for 10 days (adolescents or adults)
Erythromycin estolate 20-40 mg/kg/day in 2-4 divided doses PO for 10 days
Erythromycin ethyl succinate 40 mg/kg/day in 2-4 divided doses PO for 10 days
Benzathine penicillin 600,000 U for pts <27 kg (60 lb) as single IM injection OR 1,200,000 U for pts >27 kg (60 lb) as single IM injection
Cefpodoxime proxetil 10 mg/kg/day 2 times/day PO for 5 days
Azithromycin 12 mg/kg/day once a day PO for 5 days
Cefadroxil * 30 mg/kg/day 2 times/day PO for 5 days
Cefuroxime axetil * 20 mg/kg/day 2 times/day PO for 4-5 days

*These short course regimens are still pending FDA approval.[For more information about the proper diagnosis and treatment of GAS pharyngitis and rheumatic fever, refer to the 1997 Red Book, pages 483-494. Short course regimens for GAS pharyngitis are also described in Dajani AS. Current Therapy of Group A Streptococcal Pharyngitis. Pediatric Annals 1998; 27(5): 277-280.

Return

 

Caution: Ticks Ahead Report on Selected Vector-borne Diseases Utah 1990-1997

With the recent wet weather, the ground cover will be thick and green making it a good home for ticks. Health care providers should be on the lookout for vector-borne diseases and make sure their patients are tested appropriately. The following is a brief description of the vector-borne diseases found in Utah and their prevalence.

The most commonly reported vector-borne disease in Utah is Colorado Tick Fever (CTF). The Colorado Tick Fever virus causes the disease. The virus is maintained in a wild rodent reservoir and is transmitted to humans by the bite of the Rocky Mountain wood tick (Dermacentor andersoni). CTF is endemic to Western U.S. and Canada at elevations above 5,000 feet. For the eight-year period, 1990-1997, there were 93 reported cases of CTF in Utah residents (Table 1). The highest number of cases, twenty-three, occurred in 1993; while the lowest, four, was reported in 1996. The county of residence with the highest cumulative incidence (per 100,000) was Wasatch County (27.43) followed by Summit (6.94). Sixty-one percent of the cases were male. Ages of cases ranged from one to 90 years of age, with the mean age being 35.7 years of age (Male: 1-90 years, mean 38.7 years, Female: 3-76 years, mean 30.5 years).

Twenty-three cases of tularemia were reported in Utah for 1990-1997 (Table 1). One of these cases died. Of the cases, 87% were male. Ages of the patients ranged from two to 75 years of age with the median age being 38.2 years. Seven of the cases had an unknown exposure. Of those cases with known exposure, five were associated with deer fly bites, four because of a cat bite or scratch, three from contact with rabbits or rabbit pelts, and one from a tick bite.

Tularemia, also known as rabbit fever, can be transmitted through many different routes, including handling infected rabbits or other animals, ingestion of undercooked, infected meat, and by tick or deer fly bites. The incubation period for tularemia is about three days, with a range of two to ten days. Symptoms generally include chills, fever, malaise, and often enlarged glands. The presentation of this disease varies with the means by which it is acquired: ingestion of infected meat may cause pharyngitis and gastrointestinal symptoms; exposure through handling the meat may cause an ulcer on the hand; inhalation of infectious material causes pneumonia. Diagnosis is generally made through fourfold rise or greater in antibody titer between acute and convalescent serum specimens or by isolation of Francisella tularensis from ulcer exudate, lymph node aspirate or blood.

Utah has had four cases of plague reported during 1990 to 1997 (Table 1). The first three cases presented with bubonic plague. Bubonic plague is marked by a high fever and the characteristic bubo, or swollen lymph node, usually inguinal, sometimes axillary or cervical. There was no source confirmed for any of these cases. The 1994 case was a pneumonic plague case that was acquired from a cat. Pneumonic plague may occur as the result of secondary spread of Yersinia pestis to the lung. Primary pneumonic plague occurs as a result of inhalation of droplets expelled by an animal or human with plague pneumonia. The third form of plague is the septicemic form.

The reservoir for Yersinia pestis is wild rodents in the Western U.S. Transmission usually occurs by flea bite, though it can be transmitted through handling infected tissues of rodents or in the case of pneumonic plague, through the respiratory route. Diagnosis of plague is confirmed by culture and identification of the organism from aspirate of the bubo, from blood, or by four fold rise/fall in antibody titer. Plague is reportable immediately by telephone. Public health follow-up of cases includes identification of the source so that appropriate intervention can be made to prevent other cases. Prevention measures include avoidance of prairie dog towns, not handling or eating rodents, especially sick animals, and keeping domestic animals free of fleas.

Relapsing fever or Borrelia recurrentis (Borrelia spp.) is an uncommon illness characterized by fever episodes lasting from 3 to 6 days followed by an afebrile period of about a week. Relapses become progressively shorter and milder as the afebrile period becomes longer. A fleeting macular rash on the trunk frequently occurs. In the Western U.S. the disease is carried by a soft-bodied tick (Ornithodoros species). In the last eight years, five cases have been reported in Utah residents (Table 1).

Six cases of Rocky Mountain spotted fever (RMSF) were reported in Utah residents during the eight year period (Table 1). The disease is much more common in the south central and eastern states. Only one of the cases was known to be acquired outside of Utah. RMSF is the most serious of the tick-borne diseases.

Seventeen cases of Lyme disease have been reported in Utah residents between 1990 and 1997 (Table 1). Seventy-one percent of the cases were female and ages of the cases ranged from 2 to 68 years with a median age of 35 years. Seven cases (41%) were acquired outside of the state. The surveillance case definition used to report Lyme disease is either the presence of erythema migrans, the characteristic lesion associated with this disease, at least 5 mm in diameter; or positive serology and one of the late manifestations associated with this illness: neurologic, cardiac, or arthritic abnormalities. The incubation period for Lyme disease ranges from 3 to 32 days. Beginning symptoms include the characteristic erythema migrans, malaise, fatigue, fever, headache, stiff neck, myalgia, migratory arthralgias, or lymphadenopathy. Tick studies show that Ixodes pacificus is present in Utah, but no Borrelia burgdorferi was found in any tick or mouse studies.

The last vector-borne reportable disease to be discussed is malaria. Utah has had 30 cases of malaria reported over the past eight years (Table 1). All of the cases have been imported from outside the United States. Over one third (11) of the cases were imported from Africa, another third were imported from India (6) and Central America (6). The remaining third were imported from Indonesia (3), Philippines (1), Pakistan (1), and one with a travel history that includes several Caribbean Islands and Central America. Twenty (70%) of the cases have been male. Almost 50% of the cases were between 20 and 29 years of age.

Malaria is a parasitic disease caused by one or more of the following sporozoan parasites: Plasmodium vivax, P. malariae, P. falciparum and P. ovale. The disease is transmitted by the bite of the female Anopheles mosquito. The incubation period or time between the infective bite and the appearance of clinical symptoms is approximately 7-14 days for P. falciparum, 8-14 for P. vivax and P. ovale and 7-30 days for P. malariae. To prevent malaria, all travelers to the subtropics and tropics should check with their local health department or physician for information on malarial prophylaxis.

The State Public Health Laboratory or the Centers for Disease Control and Prevention (CDC) can test for these diseases. Physicians may call 584-8400 for further information about specimen collection and submission. Single copies of fact sheets on vector-borne diseases are available from the Bureau of Epidemiology, 538-6191.

Table 1. Cases of Vector-borne Diseases, Utah 1990-1997
Disease

1990

1991

1992

1993

1994

1995

1996

1997

Total

Colorado Tick Fever

12

16

14

23

7

11

4

6

93

Lyme Disease

1

2

6

2

3

1

1

1

17

Malaria

0

5

5

2

4

6

5

3

30

Plague

0

1

1

1

1

0

0

0

4

Relapsing Fever

1

0

1

0

0

0

2

1

5

Rocky Mountain Spotted Fever

3

0

1

0

0

1

0

1

6

Tularemia

4

6

2

2

2

0

3

4

23

Return