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Simian foamy virus isolated from an accidentally infected human individual
M Schweizer1, V Falcone, J Gänge
1Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, University of Freiburg, Germany.
Abstract:
Evidence for natural foamy virus (FV) infections in humans is still lacking. However, accidental infections of humans with simian FV have been demonstrated by serology and PCR, but all previous attempts to recover infectious virus in such cases have failed. Here we describe the isolation of a simian FV from peripheral blood mononuclear cells (PBMC) of a healthy animal caretaker, who acquired the virus 20 years ago from an African green monkey (AGM) bite. Properties of the human isolate such as host range in cell cultures including human PBMC and ability to induce neutralizing antibodies in the primate host proved to be similar to those of FV obtained from AGM. The genomic sequence of the isolate was found to be virtually identical to the proviral sequence present in the host lymphocytes and related to AGM isolates but distinct from those of all FV isolates handled in the laboratory. For successful virus isolation, it was essential to stimulate the host lymphocytes by phytohemagglutinin and interleukin-2 for 2 weeks prior to cocultivation with permissive cells. In contrast to the situation found in FV-infected monkeys, virus isolation from the saliva of the animal caretaker was not possible, and no evidence for FV transmission to family contacts was obtained. We conclude that, in contrast to active infection in monkeys, FV persists in a state of latency following accidental infection of humans.
Insights
Researchers successfully isolated simian foamy virus (FV) from a human 20 years after infection. This indicates FV persists in a latent state in humans, unlike active infections in monkeys.
Area of Science:
- Virology
- Infectious Diseases
- Primate Health
Background:
- Evidence for natural human foamy virus (FV) infections is limited.
- Accidental simian FV infections in humans are known but infectious virus recovery has failed previously.
Purpose of the Study:
- To isolate and characterize simian FV from a human with a history of exposure.
- To investigate the persistence and state of FV infection in humans.
Main Methods:
- Isolation of simian FV from peripheral blood mononuclear cells (PBMC) of an animal caretaker.
- Genomic sequencing of the isolated virus.
- Stimulation of host lymphocytes with phytohemagglutinin and interleukin-2 for virus recovery.
Main Results:
- Successfully isolated infectious simian FV from a human 20 years post-exposure.
- The human isolate showed properties similar to FV from African green monkeys (AGM).
- Genomic sequence was nearly identical to the proviral sequence in host lymphocytes and AGM isolates.
Conclusions:
- FV persists in a latent state in humans following accidental infection.
- Unlike active infections in monkeys, human FV infections appear to be non-transmissible to contacts and not shed in saliva.