Bureau of Epidemiology
Bureau of Epidemiology July 1998 Utah Department of Health
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Hantavirus is Back!  
Pertussis Persists in Children and Adults
Announcing the 5th Annual Tuberculosis Conference  
Influenza Prevention 1998 - 1999
EHEC Alert!
Monthly Morbidity Summary

 

Hantavirus is Back!

Two Utah residents have been recently diagnosed with illnesses associated with hantavirus. A case of Hantavirus Infection was diagnosed in a 32-year- old male from Juab County who became ill around the first of June. The patient was admitted to a small rural hospital for a four-day stay. He was never intubated and in fact never had significant respiratory illness. A case of Hantavirus Pulmonary Syndrome (HPS) was diagnosed in a 37-year-old man from Emery County who became ill around the first of July. The patient was seen at a rural hospital emergency room and then transferred to a tertiary care facility. After a four-day stay the patient was discharged. Along with these two Utah cases, Colorado and New Mexico have had three cases each and of the six cases, three have died.

Given the rapidity of onset, shock and respiratory failure, early recognition of the illness is critical in reducing the risk of mortality. HPS begins four days to six weeks after exposure to infected rodents or their excreta, although not all patients will give a history of rodent exposure. All patients experience a prodromal phase with fever, chills and myalgias, persisting for 1 to 7 days before progression to the cardiopulmonary phase. Pain in the legs and back can be very severe during the hantavirus prodrome. Many patients also experience nausea, vomiting, diarrhea, and abdominal pain. Cough and other upper respiratory symptoms are not present at the onset of the prodromal phase but instead begin hours before the onset of the noncardiogenic pulmonary edema.

Because there is no way to clinically distinguish between the prodrome of HPS and that of many other viral and bacterial infections, we recommend the liberal use of the complete blood count (CBC) with differential and platelet count in the appropriate setting. A low platelet count (<150,000 in 98% of cases; <130,000 in 92%) is the only CBC abnormality consistently seen during the prodromal phase. All HPS cases eventually have platelet counts <100,000. Other nonspecific lab results suggestive of prodromal HPS include elevated LDH, elevated AST, and reduced serum bicarbonate. Patients with symptoms consistent with early HPS but with platelet counts of >150,000 should be advised to return to the clinic in 24 hours for re-evaluation.

The transition from hantavirus prodrome to respiratory failure occurs 4 to 12 hours after onset of cough and shortness of breath. With the onset of pulmonary edema, the CBC now shows thrombocytopenia, elevated hematocrit, leukocytosis with circulating myelocytes, promyelocytes, and immunoblasts, recognized as large atypical lymphocytes with deep blue cytoplasm. Acidosis, abnormal PTT, elevated LDH and hepatic enzymes, and reduced serum albumin are usually seen. Serum creatinine is usually not elevated. Hypotension in HPS is due to cardiogenic shock with low cardiac output and normal or elevated peripheral vascular resistance. Patients presenting with bilateral alveolar-interstitial infiltrates, hypotension plasma lactate greater than 4 meq/L have a high case fatality.

Patients with suspected HPS (thrombocytopenia and compatible clinical picture) should be transported to a critical-care unit as early as possible, because the fluid management may require guidance by Swan-Ganz catheter data, hypotension must be treated with inotropes (initiate early treatment with dobutamine), and oxygenation may be difficult even with mechanical ventilation.

If you or your patients have general questions about the signs and symptoms of HPS, what to do after exposure to rodents, prevention of hantavirus infections, or other issues not related to a specific case of suspected HPS, the following resources are available:

Printed material and videos - Utah Department of Health - (801) 538-6191.

General information - local and state health departments, or www.cdc.gov/ncidod/diseases/hanta/hps/index.htm.

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Pertussis Persists in Children and Adults

Contrary to common belief, pertussis is not exclusively a disease of infants. In 1996, there were a total of 7,555 pertussis cases in the U.S., with 17.9% of those occurring in persons >20 years of age. In Utah, 15% of the 1996 cases were among adults and in 1997, adults made up 32% of the total cases. To date, 21% of the 1998 cases have also been in the adult population. However, the age group most frequently affected by pertussis is children under five years of age with the highest occurrence in infants under one year of age. During the past three years Utah has averaged 31 cases of pertussis yearly, while neighboring western states have experienced large outbreaks of pertussis (>400 cases).

Pertussis, also known as whooping cough, is a highly contagious bacterial infection of the respiratory tract caused by the bacterium Bordetella pertussis. Pertussis causes violent spells of coughing that may be followed by difficulty in breathing, vomiting, or "whooping". Transmission of pertussis occurs primarily by aerosol droplet and is most easily transmitted in the period starting 7 days following exposure to three weeks after the onset of spasmodic coughing. Seventy to 90 percent of susceptible household and other close contacts of a person with pertussis will develop the disease within 7 to 14 days, commonly 5 to 10 days. The disease may last up to 3 months and be complicated by pneumonia, seizures, encephalopathy or death.

Protection of infants too young for immunization requires increased awareness of pertussis by health care providers. Providers should consider the diagnosis of pertussis in children, adolescents and adults who develop cough lasting more than 7 days. The disease can be diagnosed by isolation of Bordetella pertussis from a nasopharyngeal swab. The later the culture is obtained in the course of illness (usually after 1-2 weeks), the less likely it is to be helpful in making the diagnosis. Under optimal conditions 80% of suspected cases in outbreak investigations can be confirmed by culture; in most clinical situations isolation rates are much lower. Due to the insensitivity of the test, it is critical that the specimen is collected as accurately as possible.

Transmission of pertussis may be reduced in household or close contacts by early treatment of cases with an effective antimicrobial agent. Erythromycin (40 mg/kg/day for children, 1 gram/day for adults) should be continued for a minimum of 14 days. All household and other close contacts should receive treatment, regardless of age and vaccination status. All close contacts <7 years of age, who have not received four doses of pertussis vaccine should complete the series with the minimum interval between doses.

Immunization with pertussis vaccines has reduced the number of pertussis cases and related deaths. However, due to inadequately immunized infants and children and difficulty in diagnosing the disease, pertussis remains a very real threat. The best defense currently available is to immunize children appropriately and on schedule. The newer pertussis vaccines (acellular or DTaP) are quite effective and are less reactogenic than whole cell DTP vaccines. A variety of DTaP vaccines have recently been licensed for infants and have shown high levels of efficacy. Additionally, studies are underway for assessing the use of acellular pertussis vaccines in adults. Future strategies for reducing the incidence of pertussis and possibly eradicating it may include booster immunizations for adolescents and adults.

For further information on pertussis disease, vaccines, or other vaccine preventable disease issues, contact the Utah Immunization Program, (801) 538-9450.

References: Vaccine Bulletin, February 1996; Immunization Action News, April 1994; CDC 1996 Pertussis Surveillance Summary; National Immunization Program (NIP), Background on European Studies of Acellular Pertussis Vaccine; NIP 1997 Manual for the Surveillance of Vaccine Preventable Diseases.

 

Announcing the 5th Annual Tuberculosis Conference

"The Continuum of TB Case Management"

Please join the Utah Department of Health and the American Lung Association of Utah at this year’s Tuberculosis Conference. It will be held October 20, 1998 at the State Office Building Auditorium from 8:00 AM - 4:00 PM. Cost for the one-day conference is $40 pre-registration, $45 day of registration, $20 for students and $35 per person for groups of 5 or more. Lunch is included in the registration fee.

We are happy to have as the keynote speaker Betty Gore, RN, President-Elect of the National TB Nurses Consultant Coalition and Nurse Consultant for the Division of Tuberculosis Control, South Carolina Department of Health and Environmental Control. She will be discussing different ways to use Directly Observed Therapy and incentives/enablers in the treatment of TB. There will also be a discussion on Client Case Management and a presentation on the essence of diversity in Utah. Three afternoon breakout sessions will expand on the topics above and allow the participants more time with the presenters to ask questions about current case management issues they may be encountering with clients.

For a registration form or more information please call Kaye Staker at the American Lung Association of Utah at 801-484-4456.

 

Influenza Prevention 1998 - 1999

It’s time once again to update our information concerning the vaccine and antiviral agents available for controlling influenza during the 1998-99 influenza season. Antigenic variation of both influenza A and B viruses have resulted in major epidemics of respiratory disease. The antigenic characteristics of circulating strains provided the basis for selecting the virus strains included in each year’s vaccine.

Typical influenza illness is characterized by abrupt onset of fever, myalgia, sore throat, and nonproductive cough. Unlike other common respiratory illnesses, influenza can cause severe malaise lasting several days. During influenza epidemics, high attack rates of acute illness result in both increased numbers of visits to physicians’ offices, walk-in clinics, and emergency rooms and increased hospitalizations for management of lower respiratory tract complications.

Vaccination of high-risk persons each autumn year before the influenza season is currently the most effective measure for reducing the impact of influenza. Groups at increased risk for influenza-related complications include:

Persons aged >65 years.

Residents of nursing homes and other chronic-care facilities that house persons of any age who have chronic medical conditions.

Adults and children who have chronic disorders of the pulmonary or cardiovascular systems, including children with asthma.

Adults and children who have required regular medical follow-up or hospitalization during the preceding year because of chronic metabolic diseases (including diabetes mellitus), renal dysfunction, hemoglobinopathies, or immunosuppression (including immunosuppression caused by medications).

Children and teenagers (aged six months - 18 years) who are receiving long-term aspirin therapy and therefore might be at risk for developing Reye syndrome after influenza.

Women who will be in the second or third trimesters of pregnancy during the influenza season.

Some persons at high risk can have a low antibody response to influenza vaccine. Efforts to protect these groups against influenza might be improved by reducing their exposure from their caregivers. Therefore, the following groups should also be vaccinated:

Physicians, nurses, and other personnel in both hospital and outpatient-care settings.

Employees of nursing homes and chronic-care facilities who have contact with patients or residents.

Providers of home care to persons at high risk (e.g., visiting nurses and volunteer workers).

Household members (including children) of persons in high-risk groups.

Influenza vaccine may be administered to any person who wishes to reduce the chance of becoming infected with influenza. Only those with a known anaphylactic hypersensitivity to eggs or to other components of the vaccine should not receive the influenza vaccine.

The optimal time for organized vaccination campaigns is usually from October through mid-November. The trivalent influenza vaccine prepared for the 1998-99 season will include A/Beijing/262/95-like (H1N1), A/Sydney/5/97-like (H3N2), and B/Beijing/184/93-like hemagglutinin antigens. For the B/Beijing/184/93-like antigen, U.S. manufacturers will use the antigenically equivalent strain B/Harbin/07/94 because of its growth properties.

Please refer to the MMWR, Vol.47, No.RR-6 for more information on the 1998-99 influenza season or call the Utah Department of Health, Bureau of Epidemiology at (801) 538-6191.

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EHEC Alert!

Some Utah laboratories are screening for E. coli O157:H7 using the Meridian EHEC kit. This is a very sensitive way to screen for enterohemorrhagic E. coli (EHEC). However, there are strains of EHEC that are NOT E. coli O157:H7, and therefore it may appear that the Meridian test is giving a false positive result.

If your lab is using the Meridian EHEC test, and obtains a sample that gives a positive test result and EITHER:

     - you are not culturing to find E. coli O157:H7 OR
     - you cultured for but did not find E. coli O157:H7. THEN,

PLEASE send the EHEC test broth immediately to the Utah Public Health Lab. We are actively looking for EHEC strains that are not E. coli O157:H7.

If you find E. coli O157:H7 from the broth, please submit the isolate as you normally would – the broth is not necessary.

 

Utah Department of Health, Bureau of Epidemiology
Monthly Morbidity Summary - July 1998 - Provisional Data

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The Epidemiology Newsletter is published monthly by the Utah Department of Health, Division of Epidemiology and Laboratory Services, Bureau of Epidemiology, to disseminate epidemiologic information to the health care professional and the general public.

Send comments to:

The Bureau of Epidemiology
Box 142104
Salt Lake City, UT 84114-2104
or call (801) 538-6191

Approval 8000008: Appropriation 3705

Rod Betit, Executive Director Utah Department of Health
Charles Brokopp, Dr.P.H. Division of Epidemiology and Laboratory Services
Craig R Nichols, MPA, Editor, State Epidemiologist, Director Bureau of Epidemiology
Cristie Chesler, BA Managing Editor