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Showing papers on "Viremia published in 1971"


Journal ArticleDOI
TL;DR: Parameters of infection with Marek's disease herpesvirus were studied in a flock of naturally infected White Leghorn chickens and progeny tests showed that absence of detectable viremia was unreliable as a marker for genetic resistance.
Abstract: Parameters of infection with Marek's disease herpesvirus (MDV) were studied in a flock of naturally infected White Leghorn chickens during a 76-week period. Infection appeared to persist indefinitely in the host chicken although the virus titers were variable and frequently low. Transmission of infection by contact was demonstrated for some 76-week-old survivor birds and seemed related to the titer of viremia and presence of virus in the integument. Titers of Marek's disease (MD) precipitins peaked prior to the 28th week, and in a few cases eventually disappeared; however, antibody detected by the indirect fluorescent antibody test remained undiminished. The persistence of precipitins appeared related to persistence of viral antigen. Birds with high virus titers died more frequently of MD than other birds, but virus pathogenicity could not be implicated as a determinant of survival. Duration of survival was related directly, although not causally, to antibody titer. Response differences among sire families were noted, but progeny tests showed that absence of detectable viremia was unreliable as a marker for genetic resistance.

83 citations


Journal ArticleDOI
TL;DR: The quantitative correlation between the decrease in neutralizing antibody and the increase in viremia in immunosuppressed mice suggests that antibody rather than cellular immunity may be the more important immune factor in the control of chronic vireia.
Abstract: The immunosuppressive drug cyclophosphamide was used to study the effect of immunosuppression on the degree of chronic lactic dehydrogenase virus (LDV) viremia in mice. Weekly injections of cyclophosphamide caused an increase of LDV viremia of ca. 2.5 log10 50% infectious doses per ml as compared to the viremia in the nontreated mice. This increase occurred at about the same time that the formation of antibody with a neutralization index of 2 to 3 log10 per ml could be demonstrated in the serum of control mice, whereas both neutralizing antibody and sensitized (antibody-bound but infectious) virus were absent in the immunosuppressed mice. In one experiment, antibody did not reappear 28 weeks after a 24-week course of cyclophosphamide treatment. In another experiment in which the drug was given for 12 weeks, antibody appeared again in the treated mice 14 weeks after cessation of drug administration and was accompanied by a decrease in viremia. The normal decrease of early viremia during the first 2 weeks of infection in immunosuppressed mice suggests that the immune response is not the cause of this initial decrease in LDV viremia but that interferon and perhaps other nonimmune factors may be involved here. The increased viremia in the immunosuppressed mice during the later stages of infection indicates that the immune response plays an important role in partial control of chronic viremia. The quantitative correlation between the decrease in neutralizing antibody and the increase in viremia in immunosuppressed mice suggests that antibody rather than cellular immunity may be the more important immune factor in the control of chronic viremia.

24 citations


Journal Article
TL;DR: In this paper, a group of 119 unselected cases of the sudden infant death syndrome (SIDS) were studied for evidence of viremia, and none of 20 cases studied by standard culture methods yielded virus in the blood, and only 4 of 119 had detectable levels of serum interferon.
Abstract: A group of 119 unselected cases of the sudden infant death syndrome (SIDS) were studied for evidence of viremia. None of 20 cases studied by standard culture methods yielded virus in the blood, and only 4 of 119 had detectable levels of serum interferon. Coupled with previous studies, the data further suggest that viral infection, if it participates in the ultimate mechanism in SIDS, does not act by means of overwhelming viremia but rather may act locally, possibly in the respiratory tract.

12 citations


Journal ArticleDOI
TL;DR: The resistance of M. musc.
Abstract: Natural hosts for arboviruses often show high viremia but do not develop disease. In the present study the role of interferon production was examined in two species of mice —Mus musculus spicilegus (M. musc, spic) and Swiss albino mice — infected with TBE virus. Whereas M. musc. spic. developed high viremia but survived, Swiss albino mice showed a less high degree of viremia but succumbed to a fatal disease. In the blood at time of viremia there was no difference in interferon contents between the two species of mice. In the brain, however, M. musc. spic. exhibited low virus titers and also low levels of interferon, while Swiss mice contained high titers both of virus and interferon. Thus, the resistance of M. musc. spic. to TBE virus cannot be attributed to the protective effect of interferon.