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Organization about the significance of these agents and the need for international collabora- tive research in this field.
Several species of monkeys and apes, in the wild and in captivity, harbor retroviruses. Three exogenous retroviruses have been isolated re- cently from Old World primates: simian T-lym- photropic viruses (STLV) types I and III and Mason-Pfizer monkey virus (MPMV)-related agents. Included in the species that may be in- fected with such viruses are African green and Rhesus monkeys, the tissues of which are used for preparation of reagents and vaccines.
STLV I, STLV III, and MPMV-related vi- ruses have been isolated from monkeys suffering from immunodeficiency diseases in several U.S. primate centers. STLV III is clearly distinguish- able from human T-lymphotropic retroviruses but shares structural and antigenic properties. STLV III has recently been isolated from apparent- ly healthy African green monkeys imported from Africa to the United States. Serologic studies of African green monkeys held in captivity in the United States and Europe or caught in the wild in Africa indicate that a proportion of these ani- mals may be infected by STLV III. It is not known how long such viruses have been present in African green and Rhesus monkeys, but serologic evidence suggests that green monkeys in Africa may have harbored agents similar to STLV III for more than 20 years.
The group felt that the findings about simian T-lymphotropic retroviruses had the following
PAHO BULLETIN l vol. 19, no. 4, 1985
implications for preparation and use of monkey kidney cell cultures:
l By analogy to their human counterparts, it is
probable that the replication of simian T-lymphotropic viruses in vitro is restricted to lymphocytes. Monkey kidney cell cultures would be expected to contain few, if any, T-lymphocytes.
0 During the 1970s representative bulk and final preparations of live polio vaccines prepared in African green monkey kidney cultures were tested for the presence of retroviruses by reverse transcriptase as- says. In addition, primary monkey kidney cell cul- tures, including those from African green monkeys, were examined after chemical induction by electron microscopy for virus-like particles and for particle-as- sociated reverse transcriptase activity. No evidence that retroviruses were present was obtained.
l Current tests of WHO poliovirus types 1, 2, and
3 vaccine seed stocks, as well as testing of more than 20 vaccine lots in Europe and North America, have failed to yield evidence of retroviruses.
l Long-term and continuing followup of recipients of live polio vaccine suggest the absence of adverse effects potentially associated with retrovirus.
The WHO group also concluded that studies of the molecular structure and biology of lym- photropic retroviruses from non-human primates offer unique models relevant to the study of the human counterpart viruses. They therefore recom- mended appropriate plans to make effective use of existing knowledge and outlined a coordi- nated program of research.
Source: World Health Organization, Weekly Epide- mrological Record 60(35):269-270, 1985.
SMALLPOX VACCINATION AND CONTACT SPREAD OF VACCINIA VIRUS Another case of vaccinia virus infection trans-
mitted from a military-related person recently vaccinated against smallpox has been reported in the United States.
On 24 January 1985, a girl 15 years of age was referred to a dermatologist in a clinic at La Crosse, Wisconsin, for evaluation of an ulcerated lesion on her left upper lip. Examination of the patient revealed an ulcer 2 cm in diameter on the left upper lip, five oval vesicles 4 mm in
diameter on the arms, and marked conjunctival infection of the left eye. The girl appeared mildly sick with low-grade fever, fatigue, and tender cervical lymphadenopathy. Vaccinia virus was cultured from the skin lesions.
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A male friend of the patient, a member of the Wisconsin National Guard, received a smallpox vaccination in a U.S. Army facility in Wisconsin at the end of December 1984. In early January the patient assisted her friend in applying com- presses to ease the discomfort of a successful smallpox vaccination.
An investigation conducted to determine whether the patient had transmitted disease to her contacts involved five immediate family members and 45 participants in a girls’ gymnas- tics meet on 21 January in which the patient competed. As of 3 1 January 1985, none of these 50 individuals showed evidence of vesicular or pustular skin lesions.
Note: Since the eradication of smallpox from
the world was certified in 1979, several episodes of transmission of vaccinia virus from recently vaccinated military-related personnel have been reported from Canada, the United Kingdom, and the United States. The largest outbreak of vac- cinia virus contact spread, which occurred in December 1980 and January 1981 in Canada, resulted in six cases. Four of these cases were contracted directly from an army recruit and the other two came from a patient of the first genera- tion. In all other reported episodes, the virus
spread was limited to the immediate contacts of the vaccinees. None of those infected were found to have been successfully vaccinated against smallpox in their childhood.
At present, because vaccination of civilian populations has been discontinued, the propor- tion of adolescents and young adults not vacci- nated in childhood is steadily increasing. In ad- dition to being more vulnerable than children to the complications associated with vaccinia virus, these age groups are more frequently ex- posed to military recruits of their own age.
The WHO Committee on Grthopoxvirus Infec- tions, meeting in March 1984, noted that smallpox vaccination of military personnel had been discontinued in eight countries and expressed hope that other countries would elect to do likewise and report to WHO on such decisions. For those countries that have not yet decided to discontinue vaccination of military personnel, the committee recommended that vaccinees be confined to their bases and prevented from con- tacting unvaccinated persons for a period of two weeks following the vaccination.
Source: World Health Organization, Weekly Epide-
miological Record 60(33):259-260, 1985.
HEPATITIS IN THE AMERICAS Introduction
Viral hepatitis is currently a major cause of acute and chronic illness and mortality in all parts of the world. Several causative agents- hepatitis A virus (HAV) , hepatitis B virus (HBV) , and delta virus-are well characterized, and at least three others currently defined as non-A, non-B agents (two blood- or transfusion-asso- ciated forms and one epidemic form) are being studied. Worldwide, hepatitis A is known only to cause acute hepatitis, primarily in children. Both hepatitis B and the post-transfusion-asso- ciated non-A, non-B agents, however, have been associated with a chronic carrier state and with
long-term consequences that include chronic hepatitis and cirrhosis. In addition, hepatitis B virus infection is strongly associated with pri- mary hepatocellular cancer (PHC). Most PHC cases have HBV detectable in serum and HBV deoxyribonucleic acid (DNA) integrated in liver tissue. Prospective studies in Taiwan and Japan have estimated that the relative risk of HB car- riers developing PHC is over 200 times that of other persons.
