Disease Control Bulletin: April 1999

Contents

disease control bulletin

Volume 1, Issue 2, 1999

Hepatitis C

In the next two months two nationwide events will affect every health professional’s need to be current on hepatitis C issues. First, the American Red Cross (ARC) will initiate a Look back Program, to include all persons who received blood from donors who were later identified to be hepatitis C antibody positive. In May, the Centers for Disease Control and Prevention (CDC) will launch a massive education campaign to alert persons at risk for hepatitis C to seek counseling, testing, and evaluation as necessary. Included in those risk criteria will be anyone who received blood transfusions before 1992. Health care providers may receive questions from persons with vague symptoms and concerns about past risk factors and behaviors.

American Red Cross HCV Lookback Program

The Food and Drug Administration (FDA) issued a new guideline on September 23, 1998 that requires all blood collection facilities and transfusions services to perform an HCV Lookback Program. In May 1990 routine testing of blood donors was initiated; in July 1992 an even more sensitive multi-antigen test was implemented. The ARC began a retrospective review in March of 1999, looking at all donors who tested positive for antibody to HCV since early 1992 who had previously donated blood before testing was available. These searches should identify recipients who received blood from donors who later were identified as testing anti-HCV positive.

The ARC will send notification packets to the physician of record of patients identified as possibly exposed to blood products infectious for hepatitis C. These packets will contain a letter of explanation for the physician, a letter to be sent to the patient, patient education fact sheets, and a list of resources. The patients’ letters will indicate where to present for testing and provide telephone numbers to call for additional information.

CDC Recommendations for Prevention and Control of HCV

CDC mailed educational packets to 200,000 physicians during the summer of 1998 which contained an audiotape and written information about hepatitis C. In addition, CDC published recommendations for prevention and control of hepatitis C in the MMWR, October 16, 1998. Copies of this document may be obtained by mail, phone, fax, e-mail, or it can be downloaded on to a computer. (Request MMWR October16,1998,Vol.47#RR-19; include contact information.) See box on contact information.

Hepatitis C: Prevalence

Hepatitis C is the most common chronic bloodborne infection in the United States. It is estimated that 3.9 million Americans are infected, most without their knowledge. The prevalence of disease in the United States is thought to be 1.8%. The prevalence in Vermonters is unknown. However, since 1994, over 1500 persons have been reported to have tested positive to the antibody (including acute, chronic, resolved, and perhaps also false-positive results).

Risk Factors

Exposure to blood or blood components: Before 1983 when deferral of persons with risk factors associated with the newly recognized HIV infection was initiated, the most significant risk characteristic for HCV (then known as non-A/non-B hepatitis) was being a blood transfusion or blood component recipient. Measures taken since 1983 to protect the blood supply have greatly reduced transmission. Since 1994 transfusion-transmitted HCV has not been detected. A trial of a new screening test will begin in May 1999 in the New England Region of the American Red Cross. This new test, Nucleic Acid Testing (NAT) works on the principle of gene amplification, to allow earlier detection of the virus. Persons who received blood or blood components before testing was available and persons who received blood from persons later identified as having hepatitis C should be tested.

Injectable drug use: Persons who inject drugs currently account for most of the HCV transmission in the US. Those who injected drugs in the past, even limited or occasional injectable drug use, may have unidentified chronic infection. There is some concern that intranasal cocaine use may place persons at risk of transmission through the sharing of contaminated straws.

Sexual exposure: Considerable inconsistency exists among studies on sexual transmission. Data indicate that sexual transmission of hepatitis C appears to occur, but that the virus is inefficiently spread through this manner. Transmission may be more efficient from males to females. Persons with multiple sexp artners, with an HCV-infected partner, or persons with a history of having had other sexually transmitted diseases should be considered potentially at risk

Renal Dialysis: Studies have found prevalence of hepatitis Cinchronic hemodialysis setting rangesfrom10-60%. There is an association between positive antibody status and length of time on dialysis, indicating there may be a causal relationship. Noso-comial transmission of the virus in these settings is a possibility if accepted standards of infection control are not in place.

Exposure to bloodborne pathogens in the workplace: The prevalence of HCV infection in healthcare workers is not greater than in the general population. However, history of unintentional needlestick or sharps injury on-the-job is associated with a higher risk. Conversion rates in published literature range from 1.2-10% following bona fide documented exposure to an HCV infected source patient. The most recently cited rate from the January 1999 issue of “Infection Control and Hospital Epidemiology” is 4%. Healthcare workers who have had needlestick injuries should learn of their antibody status.

Perinatal exposure: While the prevalence is low in newborns of hepatitis C infected mothers, 5% of these infants become infected at the time of birth. The rate of transmission of infection is higher if the mother is co-infected with HIV. Current data indicate that there is no difference in transmission between infants delivered vaginally and those delivered by Cesarean method. There is no documentation of transmission of hepatitis C through breastfeeding. Passively acquired maternal antibody may persist for months, but probably less than a year. Therefore, testing of infants for antibody to hepatitis C should be delayed until after the child’s first birthday.

Household contact: Transmission to nonsexual household contacts of persons with hepatitis C is probably uncommon, although case-controlled studies have shown an association between household contact and acquiring hepatitis C. The mechanism could be inapparent percutaneous or permucosal exposure to infectious blood or other body fluids. Sharing of personal care items should routinely be avoided.

Spectrum of Disease

Hepatitis C virus is a single-stranded RNA virus in the flavivirus family (others include dengue and yellow fever). It is classified in six major genotypes numerous sub-types, and quasi-species based on sequence data. Like other single-stranded RNA viruses (including HIV), hepatitis C mutates faster than the body can launch an immune response. The virus continuously appears to be foreign because the neutralizing antibody manufactured in response to an earlier version of the virus no longer recognizes the mutated virus. Also, the host may be coinfected with heterogeneous sub-types that also are mutating. These mutations produce viruses resistant to the antibody produced by the host, interfering with the development of neutralizing antibody responses.

This phenomenon is what makes it difficult for persons to develop active immunity to this disease, perhaps explaining the preponderance for chronicity. This also makes development of effective vaccination strategies for hepatitis C difficult.

Antibody to hepatitis C can be detected using second generation enzyme immunoassay, EIA tests within three months of infection in over 97% of infected persons. Supplementary recombinant immunoblot assay (RIBA) tests are performed to screen for false positive EIA results. These are most common in persons with rheumatoid factor or high levels of immunoglobulins. Reverse transcriptase polymerase chain reaction tests (RT-PCR) using gene amplification techniques can detect the virus 1-2 weeks after exposure in over 95% of persons with acute hepatitis C. One should note that the RT-PCR kits are for research purposes only. Although, not FDA approved, RT-PCR tests are commonly in use in clinical practice. Special handling of these tests is necessary to minimize false-negative results. Also, ALT levels will rise, up to 20 times normal, 4-8 weeks after infection, these levels fluctuate and may escape detection. See algorithm for testing guidelines. See box for indications for testing.

Acute infection: Acute hepatitis C virus infection has not been well studied, as it has been difficult to identify. Typically, between 4-12 weeks following exposure, acute infection, mild constitutional“flu-like” symptoms, presents in 60-70% of persons infected. For those with symptoms, onset is insidious, with anorexia, vague abdominal discomfort, nausea, and vomiting. Jaundice is seen in only a third of cases. Some may develop more severe disease, while others may be entirely asymptomatic.

The average period of time from exposure to symptoms, for those who develop them, is 6-7 weeks. The average time period from exposure to seroconversion is 8-9 weeks; hence even persons with symptoms may be hard to diagnose until after laboratory evaluation can confirm seroconversion. In the 30-40% of symptomatic persons, antibody to hepatitis C may not be detected until 2-8 weeks after onset of symptoms. Fluctuating and elevated ALT levels are not uncommon. One cannot rely on elevated ALT levels as a marker for infection, as the infected person may have normal levels, or may have fluctuating levels and transient elevation could be missed on sporadic testing. It is believed that between 15-25% of persons are able to mount a sufficient immune response and resolve acute infection without residual sequelae. However, no clinical or epidemiological features have been identified that are predictive of persistent infection or chronic liver disease.

Chronic infection: Current literature suggests that primary infection will lead to chronic infection in 75-85% of those afflicted. ALT levels are persistently or intermittently elevated in 60-70% of these people. The most frequently cited symptomis fatigue; some complain of nausea, anorexia, and arthralgia. A small percentage of persons with chronic hepatitis C exhibit extra-hepatitic manifestations, perhaps due to repeated stress to the immune system. Hepatitis C may be present in some persons presenting with the following conditions: essential mixed cryoglobulinemia (EMC), glomerulonephritis,porphyriacutaneatarda(PCT).Itisalsoseen in persons with cutaneous conditions, including: lichen planus, polyarteritis nodosa, erythema nodosum, erythema multiforme, urticaria, and cutaneous vasculitis.

Sequelae: Chronic hepatitis C is the leading cause of liver transplantation in the US. Current estimates are that chronic hepatitis C leads to cirrhosis in 10–30% of cases within 20 years, 1-5% will develop hepatocellular cancer within 30 years. Up to 10,000 deaths occur in the U.S. annually from complication of hepatitis C. The March 11, 1999 issue of The New England Journal of Medicine reports the rising incidence of hepatocellular carcinoma noted in younger men over the past two decades. It is expected that due to the large pool of persons who were infected with hepatitis C in the 1960s and 1970s, there will continue to be a rise in the number of deaths and burden of morbidity.

Treatment issues: Clinical management and treatment modalities are beyond the scope of this article. The health care provider should be aware that there are evolving protocols and indications for initiation of these. In recent clinical trials combination of interferon alpha-2b with ribavirin was found to be 28-66% effective in eradication of the virus.

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Hepatitis C

Persons for whom HCV testing is recommended

Persons for whom HCV testing may be indicated following recognized exposure

Persons for whom the need for routine HCV testing is uncertain

Persons for whom routine HCV testing is not recommended

Contact Information for the latest CDC Recommendations

Mail: National Prevention Information Network PO Box 6003 Rockville, MD 20850 Phone: (800) 458-5231 Fax: (301) 592-8601 E-mail: HepatitisC@prospectassoc.com

Electronic copy: ftp://ftp.cdc.gov/pub/publications/mmwr/rr/rr4719.pdf

WEB SITES FOR MORE INFO ON HEPATITIS C

Persons for whom treatment should be considered*

Treatment is recommended for patients >18 or <60 years, with chronic hepatitis C who are at greatest risk of progression to cirrhosis

Persons for whom the need for treatment is unclear

Persons for whom treatment is not recommended

*Because of ongoing advances in the field of antiviral therapy, readers should consult with specialists knowledgeable on treatment issues.

PATIENT EDUCATION

Counseling of persons identified as having hepatitis C should include the following:

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Chronic Disease in Vermont: Stroke

Trends in Stroke Morbidity and Mortality

Stroke (ICD9:430-438) is the third leading cause of death in Vermont and in the United States. In 1997, the Vermont age-adjusted (1) stroke mortality rate was 23.5 per 100,000 with a 95% confidence interval (CI) of [22.4,24.7]. In 1995, only 14 states had lower age-adjusted stroke mortality rates than Vermont. In 1995, Vermont’s age-adjusted mortality rate for stroke was almost identical to New Hampshire’s rate but higher than other New England states. Nationally (2) and in Vermont, death rates from stroke double for every 5 years of age after age 55. Figure 1 shows stroke death rates for the oldest and youngest age groups most affected by stroke. (A small number of Vermonters under 55 also have strokes each year.) U.S. stroke mortality may be rising after a long decline(2). In Vermont, stroke mortality declined from 1980 to 1990 and then reached a plateau that continued through the most recent data in 1997(seeFigure1).Since1990,neitheragegroup’smortalityrates have declined significantly; however, stroke hospitalization has increased 2.9 percent per year. This increase in stroke hospitalizations since 1990 was not evenly distributed across all age groups: The 55-74 age group had an increase of 4 percent per year 95%CI[2.5%, 5.5%] and the 75+ age group had an increase of 1.9 percent per year 95% CI [0.6%,3.3%].

vermont stroke death rates by age 1980-1997

Both the age-adjusted stroke mortality and the age-adjusted hospitalization rate were consistently higher for men than for women from 1980 to 1996 (p<0.05) although the size of the difference was much greater for hospitalizations. In 1997, men had 192 stroke hospitalizations per 100,000 (versus 139 among women) and 25 deaths per 100,000 (versus 22 among women).

Risk factors for stroke in Vermonters Age 55+

Modifiable risk factors for stroke include hypertension (systolic 140 mm Hg or higher), cigarette smoking, diabetes, elevated cholesterol (> or = 220 mg/dL), and obesity (3). The Behavioral Risk Factor Surveillance System (BRFSS) (4) collects self-report data on a representative sample of adult Vermonters. Figure 2 shows the percentage of Vermonters aged 55+ having three risk factors for stroke: hypertension risk,smoking and overweight (5).

Conclusions

Vermont’s current plateau in stroke mortality, increase in strokehospitalizations,andthelargenumberofolderVermonters with risk factors for stroke, suggest that additional strategies are needed to further reduce the occurrence of stroke.

risk factors for stroke, vermonters age 55+

References

  1. Age-adjusting standard used was the United States 1940 Standard Population.
  2. Labarthe DR. Epidemiology and Prevention of Cardiovascular Diseases: A Global Challenge. Gaithersburg, MD: Aspen Publishers, Inc. 1998. Pg. 73-89.
  3. Brownson RC, Remington PL, Davis JR, (Eds). Chronic Disease Epidemiology and Control. 2nd ed. Washington, DC: American Public Health Association, 1998. Pg. 319.
  4. Behavioral Risk Factor Surveillance System, 1997. Survey data, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention. 1998. Vermont BRFSS data provided by the Vermont Department of Health, Center for Public Health Statistics.
  5. Overweight is defined as body mass index greater than or equal to 25.0.

Look-up table available at <http://www.nhlbi.nih.gov/nhlbi/cardio/obes/ prof/guidelns/bmi_tbl.htm>. Body mass index = multiply weight in pounds by 704.5; divide result by height in inches squared according to the NIH Clinical Guidelines on the Identification, Evaluation and Treatment of Overweight and Obesity in Adults: The Evidence Report, p. X.

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Birth Reporting in Vermont

Information about births is one of the fundamental sources of public health information. Vermont law requires that the physician or midwife attendant at a birth file a birth certificate with the town clerk within 10 days, in a form prescribed by the Department of Health. The birth certificate includes confidential statistical information about the pregnancy, delivery, and condition of the baby. Today there are nearly 100 items of personal and medical information in the confidential section of the birth certificate.

Birth certificates can also be linked to infant death reports to study the causes of infant mortality. Vermont birth and infant mortality statistics are reported in many state and national publications. Birth records are also used in research to generate or test hypotheses relating to the birth process and infant mortality.

In cooperation with the Vermont Program for Quality in Health Care (VPQHC), the Department of Health has developed a quarterly birth outcomes report by hospital. The usefulness of this feedback to help hospitals improve birth outcomes depends on the quality of birth data. Therefore, the department also has begun to measure the timeliness, completeness, and accuracy of birth reporting by hospitals.

Timeliness

Parents often need their birth certificate quickly in order to return to their state or country of residence, establish eligibility for social services, or for other purposes. On average, birth certificates reach the town clerk within 10 days as required by law less than 25 percent of the time. One Vermont hospital, Grace Cottage, consistently meets the 10-day deadline. The four next-best hospitals meet the deadline from 50 to 70 percent of the time, and one hospital has not met the deadline since 1996.

Completeness

From 2 to 3 percent of Vermont birth certificates do not include the race of the mother, making Vermont the second-worst state in the nation on reporting of this item. Vermont is among the 10 worst states for missing information about the education of the mother and the race of the father. About 1 percent are missing information on prenatal care, and about 1.5 percent are missing information on smoking and weight gain during pregnancy. All of these items are important for understanding trends in Vermont birth outcomes, including low birth weight and infant mortality.

Accuracy

The department has begun to test the accuracy of birth certificates by comparing the same data elements from other sources. For example, the Special Supplemental Nutrition and Education Program for Women, Infants & Children (WIC) is a Department of Health program that provides supplemental foods and nutrition counseling for low and moderate-income mothers.

The joint WIC/Medicaid application form collects data on some characteristics that are also reported on birth certificates.

Tobacco use — Maternal smoking and drinking during pregnancy are particularly important because they are associated with low birth weight, and they should be preventable. Matching specific WIC case records with the corresponding birth certificates reveals that many Vermont hospitals underreport maternal use of tobacco and alcohol during pregnancy. According to 1997 WIC data, about 37 percent of WIC mothers used tobacco; according to the matching birth certificates only 32 percent of those mothers used tobacco. Hospital birth certificates for WIC mothers agreed with WIC records from 96 percent of the time (Gifford Hospital) down to 49 percent.

Alcohol use—According to 1997 WIC data, 9.5 percent of WIC mothers used alcohol during pregnancy, compared to 1.0 percent according to matching birth certificates. Hospital birth certificates for WIC mothers agreed with WIC records from 33 percent of the time (Brattleboro) down to 0 percent (seven hospitals).

C-sections — Hospitals report their C-section rates to VPQHC each quarter. They also report C-sections on the birth certificate. On average, hospital C-section rates from these two reporting systems agree about 94 percent of the time, and range from 97 percent (North Country and Brattleboro) down to 78 percent.

Birth defects — Birth defect registries in other states, using intensive case-finding techniques, estimate that the national birth defect rate is about 3 to 5 percent of births. However, birth certificates report a rate of only about 1 percent. In Vermont, 1.3 percent of birth certificates filed in 1997 indicated one or more birth defects.

Variations in Reporting Practices

The department is reviewing the procedures that Vermont hospitals use to complete the birth certificate. Practices vary widely among hospitals, and so far no clear pattern distinguishes the best from the rest. The department has met with hospital records personnel, hospital quality directors, and the Vermont Midwives Alliance, and has begun discussions with obstetricians and pediatricians. If you have ideas to help establish benchmarks and best practices, contact Don Dickson at 802-863-7395.

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Changes to Vermont School Immunization Law, School Year 1999-2000

Physician’s offices should expect an increase in calls for appointments for immunizations as well as calls from parents and school officials requesting documentation of doses previously received. Parents may be unaware that schools are not automatically notified of their child’s vaccination status and should be advised to bring their home record to the school to update records.

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Cryptosporidium in Vermont

Cryptosporidiosis, caused by the intestinal parasite Cryptosporidium parvum, has been a reportable disease in Vermont since 1996. In the first two full years of reporting, 1997 and 1998, there were a total of 44 confirmed Vermont resident cases. Cases were equally distributed between sexes, with an age range of 2 months to 82 years (median = 6 years). Cases have been reported in 9 counties with slightly more than half of the cases from Rutland and Addison counties. Cases occurred throughout the calendar year, with 54.5 percent of the onset dates during June –September. The symptoms reported by individuals with cryptosporidiosis included diarrhea (>95 percent), weight loss, cramping and low-grade fever. The median duration of diarrhea was 13 days, although the range was from 4-95 days. Four individuals were hospitalized due to dehydration, with stays of 4-13 days. During interviews with patients or family members, certain risk factors, including contact with a farm or animals, travel, drinking raw milk or untreated surface water and daycare attendance, were explored. Farm/animal contact was reported by 52.3 percent of the individuals, daycare association by 28.6 percent, and swimming, in surface water or pools, 28 percent.

Cryptosporidium has, in recent years, been associated with diarrheal illness outbreaks involving municipal water supplies and contaminated swimming pools, both in the United States and foreign countries. To date, there have been no cryptosporidium- associated outbreaks in Vermont. The main carrier of cryptosporidium is thought to be cattle, sheep and pigs, with transmission through water, soil or food, or person-to-person. Asymptomatic infections are not uncommon, and constitute a source of infection for others. The estimated incubation period is 2-14 days. In otherwise healthy individuals, symptoms usually resolve within two weeks.

Test methods for cryptosporidium oocysts include Enzyme Immunoassay (EIA), direct fluorescent antibody (FA), and microscopic examination using special stains. When patients present with symptoms suggestive of a parasitic infection, cryptosporidiosis should be considered. Providers should be aware of the test methodology available at the laboratory they utilize for parasite testing and the possible need to specifically request testing for cryptosporidium.

Cryptosporidiosis can be a serious, long-lasting, and sometimes fatal, infection in individuals with weakened immune systems. Specific information regarding cryptosporidium for HIV-infected individuals is available from the AIDS/HIV Unit of the Health Department (863-7245). Questions pertaining to private water supplies and filters can be directed to the Health Protection Division,(863-7220).General information regarding human illness is available from the Epidemiology Field Unit (863-7240).