Content Information
A. Purpose of Surveillance and Reporting
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To identify whether the case may be a source of infection for other persons (e.g., a diapered child, child care attendee, drug user or food handler) and if so, to prevent further transmission.
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To identify sources of public health concern (e.g., a salad bar prepared by an infectious food handler) and to stop transmission from such a source.
- To quickly identify contacts so that post exposure prophylaxis with hepatitis A vaccine or Immune Globulin (IG) can be given as soon as possible and within 14 days of last exposure.
B. Laboratory and Healthcare Provider Reporting Requirements
Iowa Administrative Code 641-1.3(139) stipulates that the laboratory and the healthcare provider must report. The preferred reporting method is by immediate phone call. The reporting phone number for IDPH Center for Acute Disease Epidemiology (CADE) is (800) 362-2736; fax number (515) 281-5698.
Due to potentially serious public health implications, it is requested that acute or active (IgM +) cases of hepatitis A identified in food service workers, child care employees and attendees be reported by phone to CADE immediately (800) 362-2736, so post-exposure prophylaxis can be started as soon as possible for contacts at high risk of disease. These are considered public health emergencies.
Laboratory Testing Services Available
The University of Iowa State Hygienic Laboratory (SHL) tests single serum samples for Hepatitis A IgM antibody utilizing enzyme immunoassays. Accurate information about date of collection, dates of onset of symptoms, travel history, vaccination and disease history are essential for test interpretation. For additional information on submitting samples or testing, contact the State Hygienic Laboratory at (319) 335-4500, or visit: www.shl.uiowa.edu/
C. Local Public Health Agency Follow-Up Responsibilities
Case Investigation
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Confirm the diagnosis.
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Was a hepatitis A IgM serology done?
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Yes--Continue to step 2
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No--Is the case epidemiologically linked to a confirmed case or a documented outbreak of hepatitis A?
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An epidemiologically linked case is a case that meets the clinical case definition and occurs in a person who has an epidemiologic link with a person who has laboratory-confirmed hepatitis A (i.e., household or sexual contact with an infected person during the 15-50 days before the onset of symptoms).
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Yes--Continue to b
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No--Assess if serology testing for hepatitis A IgM is indicated. If not indicated, no further investigation is necessary.
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- Is the individual's anti-HAV IgM positive?
- Yes--Continue to step 2.
- No--No further case investigation is necessary.
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- Completing the Hepatitis A Case Investigation.
Utilizing the Iowa Disease Surveillance System (IDSS) is the preferred way to conduct the investigation. The local public health agency (LPHA) should complete the Hepatitis A investigation by contacting the healthcare provider and interviewing the case and others who may be able to provide the pertinent information. Much of the information required can be obtained from the case’s healthcare provider, other involved medical providers, or the medical record. The case record will aid in determining the most probable source of the infection, whether the case is likely to transmit the infection to others, and whether contacts should be given hepatitis A vaccine or immune globulin (IG).
- Determine if the case is associated with a common-source outbreak. If yes, contact CADE at (800) 362-2736.
- Does the case know of other persons with hepatitis A or with similar symptoms?
- Have any other cases investigated provided similar information (e.g., history of eating raw oysters from a particular food establishment, etc.)
- If the case is child care-associated, refer to the managing special situations section for appropriate follow-up.
- The main objective in following up a case of hepatitis A is to determine whether the case is likely to have transmitted the infection to others.
- Determine when the acute symptoms occurred and period of communicability of the case (two weeks before to one week after onset.)
- Determine whether the case is likely to have transmitted the infection to others. Likely transmission can occur in situations where a case is identified as a food handler, a patient care provider or is an employee or child at a child care setting during their infectious period.
- Use the following guidelines to complete the case investigation form:
- Onset: Because a case of hepatitis A is most infectious in two weeks before symptom onset until one week after, be sure to accurately record each symptom and its date of onset. If onset of symptoms is unclear, use the date when jaundice was first noticed as the date of onset.
- Occupation: These questions (food handler, employment sections) are asked to determine the case’s risk of transmitting the illness during the period of communicability (14 days before onset of symptoms to 7 days after) via food, including during patient care which can involve feeding. Determine whether the case is a food handler or patient care provider. If so, appropriate control measures need to be instituted. If the case is a foodservice worker, child care, or healthcare provider, call CADE immediately at (800) 362-2736.
- Child care settings (and other similar settings): These questions are asked because hepatitis A is spread through the fecal-oral route. Children with hepatitis A are often asymptomatic; however, they may still be shedding the virus in their stool. Persons who are exposed to the fecal material of these cases could be exposed to hepatitis A. Determine whether the case is a child, resident or employee in a supervised care facility. If so, appropriate control measures need to be instituted. See child care assessment tool in the Epi Manual’s Hepatitis A section.
- Risk factors/travel: Using the incubation period for hepatitis A (2 to 6 weeks), ask the case about food consumption, supervised care settings, and other exposures during the incubation period before the illness started.
- Contact with known cases: These questions are asked because hepatitis A can be spread through household or sexual contact.
- Vaccination history for hepatitis A. Document previous doses of hepatitis A vaccine, if any.
- Travel history: These questions are asked in order to identify where the patient may have become infected. Because of poor sanitation and overcrowding, hepatitis A is endemic in many developing countries. A recent history of foreign travel may be indicative of foreign exposure.
- Food consumption: Questions about raw shellfish consumption should be asked because occasionally hepatitis A virus infection has been associated with ingestion of uncooked or partially cooked shellfish grown in sewage-contaminated waters. Ask about other high-risk foods such as salads, ice and sandwiches with lettuce and tomato. If it is suspected that the case became infected through the consumption of shellfish or other food(s), the LPHA should notify CADE, which can work in coordination with the Department of Inspection and Appeals Food and Consumer Safety Division to determine if additional control measures are warranted
- Contacts: Complete contact information documenting type of contact, symptoms (if present) and whether post exposure prophylaxis (PEP) was given, as well as the type of PEP given.
- Every effort should be made to complete the investigation because of the potential for outbreak with this disease. If several attempts have been made to obtain case information, but have been unsuccessful (e.g., the case or healthcare provider does not return calls or respond to a letter, or the case refuses to divulge information or is too ill to be interviewed), complete the IDSS case investigation form with as much information as can be gathered and notify CADE, which may be able to assist in the investigation.
After completing the case investigation, enter information into IDSS or fax along with lab reports to CADE at (515) 281-5698.