[Table of Contents]

Volume: 23S1 - January 1997

Canadian Contingency Plan for Viral Hemorrhagic Fevers and Other Related Diseases

IDENTIFICATION, SURVEILLANCE AND MANAGEMENT OF PATIENT CONTACTS

A contact is defined as a person who has been exposed to an infected person or to an infected person's secretions, excretions, or tissues within 3 weeks of the patient's onset of illness. Contacts may be subdivided into three levels of risk.

1. Casual contacts are persons who have not had close personal contact with the ill patient. These include persons on the same airplane, in the same hotel, visitors to the patient's home, etc. Since the agents associated with VHFs are usually not spread during such contact, no special surveillance is indicated unless the patient had acute respiratory involvement with intense sneezing and coughing. In such situations, exposed persons should be placed under surveillance for "close contacts". In most cases, occupational contacts of suspected patients will fall into this category.

2. Close contacts are persons who have had more than casual contact with the patient. They include persons living with the patient, nursing or serving the patient, skin-to-skin contact with or hugging the patient, and handling the patient's laboratory specimens, before the recognition of the nature of the diagnosis. These contact persons should be identified by provincial and local health departments, in collaboration with LCDC, as soon as VHF is considered a likely diagnosis for the index case. Once the diagnosis is confirmed, close contacts should be placed under surveillance. These individuals should record their temperature twice daily and report any temperature >=38.3° C or any symptom of illness to the public health officer responsible for surveillance. Surveillance should be continued for 3 weeks after the person's last contact with the index patient.
   
   Surveillance is not indicated for routine occupational contact with patients in situations where the diagnosis has been considered and appropriate isolation precautions implemented.

3. High-risk contacts are persons who have had mucous membrane contact with the patient, such as kissing or sexual intercourse, or have had a needle stick or other penetrating injury involving contact with the patient's secretions, excretions, blood, tissues, or other body fluids. These individuals should be placed under surveillance as soon as VHF is considered a likely diagnosis in the index case.

Any close or high-risk contact who develops a temperature of >=38.3° C or any other symptoms of illness should be immediately isolated and treated as a VHF patient (see "Management of the Patient"). Convalescent patients and their contacts should be warned that some of the causative agents of VHF may continue to be excreted for many weeks in semen, as demonstrated with filoviruses (e.g., Marburg and Ebola) and arenaviruses (e.g., Junin), and in urine, as occurs sometimes with Lassa virus. Collection of both seminal fluid and urine for virus isolation from male patients and urine from female patients in the convalescent period is encouraged (see "Transportation of Specimens for Diagnostic Tests"). Weekly evaluation for viral excretion is recommended. Convalescent patients must be meticulous about personal hygiene. While data are limited concerning infectivity in the convalescent period, abstinence from sexual intercourse is advised until genital fluids have been shown to be free of the virus. If the patient does engage in sexual intercourse before tests are done, the use of condoms is advised.

Post-exposure Prophylaxis

The use of ribavirin for post-exposure prophylaxis for high-risk contacts of patients with Lassa fever has not been studied. Although experience is more limited, post-exposure prophylaxis with ribavirin may be considered for high-risk contacts of patients with Crimean-Congo hemorrhagic fever. The prophylactic regimen is ribavirin 500 mg by mouth every 6 hours for 7 days. Ribavirin is not licensed for oral use in Canada, and one must request authorization from the Emergency Drug Release Program, Bureau of Pharmaceutical Assessment, Drugs Directorate (613-941-2108) during regular business hours (0830-1630 EST) and (613-941-3061) after hours. Authorized supplies of ribavirin will be supplied by the National Defence Medical Centre, Ottawa.

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