Copyright, The New York Native

The Stealth Virus

Neenyah Ostrum

Are Chronic Fatigue Syndrome patients infected with a novel virus? One of the researchers who has been pursuing a novel CFS-associated virus is Dr. W. John Martin at the University of Southern California School of Medicine in Los Angeles. For a number of years, Martin has claimed to have isolated a previously unknown virus from CFS patients. Now he has published a paper asserting that what he calls a "stealth" virus with unusual characteristics -- like being able to infect more than one species -- has been "repeatedly" cultured from a CFS patient. A description of the new virus was published in the American Journal of Pathology by Martin and colleagues in the Department of Pathology at USC. Since 1988, Martin has claimed to have found a virus in CFS patients that has some of the characteristics of both a retrovirus and a herpesvirus; at one point, he commented that he couldn't tell which type of virus it is. Although he does not expound directly upon this idea of a recombinant retro-herpesvirus in the American Journal of Pathology , Martin notes that he used retrovirus probes to identify one portion of the new virus. He also states that another portion of it is similar enough to human cytomegalovirus -- a herpesvirus -- to have evolved from it, with certain regions having "undergone multiple mutations." (1) In other words, Martin is describing a highly unusual microbe.

There are four important characteristics of this new virus that Martin and colleagues stress in the new report: It is so similar to CMV that it might have evolved from that virus; it can infect multiple species (unlike human CMV); it is able to establish a "persistent infection" in people over a number of years; and, perhaps most disturbingly, it appears to be able to escape detection by the human immune system. It is for this final reason that Martin and co-workers term the new virus a "stealth virus." (2) "The data indicate a novel type of CMV-related 'stealth' virus that is able to establish a clinically persistent human infection," Martin and colleagues state. (3)

In a page-one story in the Orange County Register , Vik Jolly reported that Martin may have found an antiviral drug that is effective against the "stealth virus." In the past four months, he has used a drug, Epione, to suppress the virus in test tubes," Jolly reported. "Testing on humans could begin in two to three months, if the Food and Drug Administration approves," Martin said.(4)

Martin has been on the trail of this putative new virus for a number of years. He provided one of the first descriptions of it at the CFIDS Association Research Conference In November 1990. In this report, Martin said the virus was probably a herpes virus. It had been isolated from the brain tissue of a 39-year-old school teacher who developed organic brain disease. (5)

The virus was uncharacterized at the time of the presentation, but Martin commented rather enigmatically that "Recent reports in this area raise the issue as to whether a herpes virus could be mistaken for a retrovirus or vice versa." (6) In a special report in the Fall 1991 CFIDS Chronicle , Martin described the new virus as a type of retrovirus -- a spuma-, or foamy, virus. (7) "Spumaviruses (foamy viruses) are classified as a subfamily of retroviruses which are characterized by their cytopathic [cell-killing] effect in tissue culture," Martin wrote. Spumaviruses kill cells, creating a "foamy" appearance when the cells clump together, and they "do not typically evoke an inflammatory response and are difficult to detect unless specifically tested for ... " (8)Spumaviruses also, Martin pointed out, are found in "a wide variety of species." (9)

To find the virus described in the 1991 report, Martin used a PCR probe that "was slightly different" from the probe used to detect HTLV-1, another retrovirus. (10)Martin also described some of the individuals from whom he had isolated this spumavirus (as of the 1991 report). The first patient was a clinical psychologist who had been diagnosed as having probable encephalitis (brain swelling). This patient experienced severe cognitive impairment, including an inability to "name items" and short-term memory loss. Subsequently, she was diagnosed with CFS. The virus was isolated from her blood and CSF [cerebral spinal fluid]. The schoolteacher from whose brain the virus was isolated was apparently patient number two. (11) A third patient described by Martin was a physician (an ear, nose and throat specialist) who had experienced painful "changes on his tongue" and asked Martin to biopsy it. The physician's tongue, blood, and CSF were all found to be positive for the virus. (12) Martin's description of his virus findings at a CFS meeting in San Francisco a few months later in the summer 1991, along with other ongoing viral research, resulted in a meeting being held at the Centers for Disease Control September 21-22, as was reported in the Wall Street Journal, New York Times , and Newsweek . (13-15) Lawrence K. Altman reported in the New York Times that Martin said he had isolated the virus from the blood and spinal fluid of ten CFS patients. "Suggestive evidence of the virus was detected in the blood of virtually all of 180 people with the syndrome who's blood was tested in his laboratory but in none of 170 without the syndrome, Dr. Martin said," according to Altman. (16) Geoffrey Cowley's Newsweek article reported that Martin began studying this virus in 1988, and believed it to be a spumavirus. Other researchers "nonetheless cite several grounds for skepticism," Cowley noted, including the fact that "foamy virus is just one of several that can make cultured cells swell up and agglomerate." (17)

In a 1992 textbook, however, while Martin states that "CPE and electron micrographic appearances were suggestive of foamy or spumaviruses," he again described it as a possible hybrid between herpes and retroviruses: "The culture findings add considerable support to the evidence from PCR that CFS patients are persistently infected with a virus that shares some features with both herpesviruses and retroviruses," Martin wrote in the textbook. "This could be explained by a recombinant virus containing both retroviral and herpesviral sequences .... " (18)

Martin and his colleagues are somewhat more cautious in their description of the putative new virus in the American Journal of Pathology . Although they note that the PCR probes used are HTLVs and that there is considerable identity with part of the sequence -- the genetic code -- of cytomegalovirus, a herpesvirus, they do not refer to it as a type of hybrid retro-herpesvirus.

The CFS patient from whom Martin and colleagues isolated the virus described in the American Journal of Pathology is 43-year-old health care provider referred to by the initials "DW." She was apparently health until falling ill in August 1990 with "an acute onset illness" characterized by "intense headaches," fever, general muscle aches, and sore throat. She was hospitalized for possible encephalitis (swelling of the brain produced usually by a virus). The patient never fully recovered from this acute illness, and was subsequently diagnosed with CFS. Lingering symptoms included "overwhelming fatigue" and a concomitant inablility to work, severe headaches, nonrestorative sleep, and impaired cognitive functions, including memory loss and difficulty naming items ("dysnomia"). (19) Blood from patient DW was initially cultured in human fibroblasts, connective tissue cells that form tissues such as tendons and encase the colon. After the blood cultures grew in the laboratory for eight weeks, a cytopathic effect (CPE), or cell death, was observed. (20) CPE in cell culture is generally interpreted to signal the presence of an infectious agent that is killing the cells. The CPE visible in human fibroblast cells was also seen when DW's blood was cultured with several different types of laboratory cell lines. "The CPE was transferable to secondary and subsequent cultures of these cells," Martin and colleagues note. This suggests that something -- presumably an infectious agent -- is present in the cell cultures and is killing the cells (as opposed to the cells dying for some other reason, like lack of proper media on which to grow). (21) "CPE was also readily transferable to murine [mouse and rat], feline [cat], rabbit, hamster, duck, and chicken fibroblastic cell lines and to various long-term human cell lines of epithelial, glial, and lymphoid origin," Martin and co-workers add. In other words: Not only does something in these cultures kill human fibroblast cells (in the laboratory), it also kills other types of human cells -- skin, nervous system, and blood cells -- as well as cells from several other species . Electron microscopy of the "infected cultures" showed "enveloped viruses approximately 180 to 200 nm in diameter," Martin and colleagues report. The infected cells resembled cells infected with CMV, they add. (22) Infected cells from lab cultures were exposed to "commercial typing antibodies" -- antibody tests used by commercial labs to test people for EBV infection, for example -- for CMV, HHV-6, herpes simplex virus, adenoviruses, and enteroviruses. The cells did not react positively to any of them. Blood from the patient also "gave negative reactions" for antibody tests (ELISA) for HIV, HTLV, and HHV-6. (23)

In contrast to these findings, patient DW had tested positive for antibodies to CMV and EBV at the time of her initial hospitalization, Martin and co-workers note. (24)Additionally, the patient's blood reacted positively (in an immunofluorescence assay) with very weak concentration of infected cells from the tissue culture. This suggests that the patient's immune system was very sensitized to this putative new virus. "Quantitatively, similar reactions were seen, however, with sera [blood] from many normal individuals tested," Martin and colleagues add. (25) So "healthy" individuals tested positive for this new virus -- what does that mean? It means either that the test being used is not working -- since it is detecting the putative new virus in control subjects as well as in the patient -- or that not everyone who is infected exhibits symptoms, and so appears to be healthy.

Martin and co-workers comment that, because blood cultures from this patient have yielded "strong CPE" consistently -- in 15 of 18 cultures in different kinds of cells over three years -- lab contamination probably does not explain the observed cell death. (26) In addition to being cultured from the patient's blood, " The virus has also been cultured from CSF [cerebral spinal fluid] collected from the patient during a 1991 hospital admission," Martin and colleagues report. The patient's spinal fluid was "otherwise unremarkable" they note. (27)

Martin and co-workers describe some of the characteristics of the new virus in very technical detail. Of interest to this discussion, however, is that a portion of what they assume to be DNA from the new virus is largely identical to CMV. The virus was examined using PCR (polymerase chain reaction). Several probes were used for the PCR studies. One set of probes was from a region common to several herpesviruses : CMV, herpes simplex-1 varicella zoster virus, and HHV-6. A second probe detected regions that occur in retroviruses. HTLV-I and HTLV-II. (28) Two distinct regions of the new virus's DNA were isolated in the PCR studies. The smaller piece of viral DNA did not appear to be similar to any known virus (when compared to data at a centralized repository of DNA sequences called GenBank). (29) The larger piece of DNA, however, "showed highly significant" similarity to a strain of CMV, Martin and colleagues report. A portion of CMV's sequence "showed a highly significant 66 percent identity with a similar sized region" of the DNA from the new virus (called fragment "15-5-2") isolated using PCR. (30) In other words: Within a piece of the viral DNA identified by PCR, there is a section two-thirds of which -- 66 percent -- is identical to a section of CMV. These researchers note that this finding is "consistent with a CMV origin of at least part of the genetic material isolated from the infected cultures." They do not think that what they have found is merely a strain of CMV, as they explain: "The cultured virus is distinguishable from CMV, however, by the following criteria: growth in cells in cells from multiple species; the vacuolated, syncytial nature of the CPE; the lack of specific staining with CMV typing sera; the negative PCR results using CM-specific primers; unrelatedness of the sequence of the PCR product 15-5-2 to that of CMV, and the apparent difference in the size of the genome [i.e., the virus]." Martin and co-workers suggest that this new virus evolved from CMV. The difference between even the similar section of the new virus and the CMV prototype virus is greater than "the estimated 5 percent divergence observed between clinical CMV isolates," they remark. "This suggests that if derived from human CMV, this region of the viral genome has undergone multiple mutations. Preliminary partial sequencing of additional clones has strengthened this assessment with several clones showing a distant relatedness to various limited regions of the CMV genome ...." (31)

The four defining characteristics of the new virus are: Its genetic sequence is similar enough to CMV that it might have evolved from CMV; it can infect more than one species (unlike human CMV); it can establish a "persistent infection" over many years; and it appears to be able to elude detection by the human immune system. In the closing paragraphs of their report, Martin and colleagues discuss these four characteristics in some detail:

Repeated culturing of the virus from the patient's blood over a 3-year period indicates that the virus has established a clinically persistent infection in the patient. Isolation of the virus from CSF and the absence of an accompanying inflammatory response suggest that the virus is neurotropic [kills nerve cells] and yet noninflammatory .... The major I-E gene of CMV was not detectable using either PCR or monoclonal antibody assays. It is conceivable, therefore, that the virus has arisen from CMV but that portions of its genetic machinery have been deleted or mutated as a mechanism of avoiding immune recognition. The absence of certain genes may also reduce susceptibility to cellular factors that restrict the interspecies growth of human CMV in animal cell lines. This would explain the broad in vitro host range of the virus.

Ongoing studies indicate that atypical viruses can be isolated from patients with a variety of neurological, psychiatric, autoimmune diseases, as well as some asymptomatic individuals. The viruses are cytopathic for fibroblasts and other cell types of multiple species and do not give typical reactions in immunological and molecular probe assays for known human herpesviruses. Because of the absence of overt clinical signs of an inflammatory reaction in many of these patients, we have tentatively termed these agents stealth viruses ... (32)

One of those "stealth viruses" "crossreacts strongly" with the portions of virus described by Martin and colleagues. "This isolate came from an otherwise normal CSF [cerebral spinal fluid] sample of a patient with severe encephalopathy complicating a four-year history of a manic depressive illness," they report. (33) However, they have found "no relatedness" between other "stealth viruses" and their new virus, Martin and co-workers report, suggesting "considerable molecular heterogeneity between isolates" despite the fact that they all seem to kill fibroblasts. In other words, Martin and colleagues are attempting to show that their virus is unique from all other stealth viruses already isolated.

In the final sentence of their report, these researchers comment that "The potential role of stealth viruses in CFS and other illnesses is currently being investigated in an animal model." Sources have told the Native that this animal model is a cat, but that information has not yet been verified.

The other active virus found in CFS (and "AIDS") patients is, of course, Human Herpes Virus 6 (HHV-6). It , too, infects multiple species, not only in the laboratory but also in nature. (34, 35) And, like Martin's "stealth virus," HHV-6 is very similar to CMV. (36) The sequence identity -- the part that is identical in both viruses -- between portions of CMV and HHV-6 was first published in The Lancet in January 1988. Dr. S. Efstathiou at the University of Cambridge (Cambridge, England) and colleges in London compared HHV-6 to other human herpesviruses. (37) "Only HHV-6 and HCMV have significant nucleotide similarity with an overall 66 percent identity accounting for our hybridization data," Efstathiou and colleagues reported. (38) While they concluded that HHV-6 is "distinct from other human herpesviruses," they also caution "that care be taken" when attempting to detect HHV-6 so as not to confuse it with HCMV. (39) In September 1988, an Australian team reported, also in The Lancet , that antibodies to HHV-6 and CMV could increase simultaneously, another factor that could lead to confusion about which virus was present and causing disease. (40) The Australian researchers reported that patients who had been "thought to have CMV infection" actually were infected with HHV-6 as well. They note that it should be determined whether "the antibody rises we have demonstrated are against multiple proteins of both viruses, or against multiple proteins of one virus plus a cross-reactive protein antigen other the other one." (41) Robert Gallo and the team at the National Cancer Institute claiming credit for discovering HHV-6 disputed both of these reports in the January 28, 1989, issue of The Lancet. They note that, "In our initial report on HHV-6, we described studies recording a lack of cross-reactivity between CMV and HHV-6 .... " (42) Gallo and colleagues also belittle both research teams' methodologies: "If cross-reactivity had been found after adsorption, isolation of the putative cross-reactive antibodies and proof that they were cross-reactive would have been necessary, before suggesting cross-reactivity," they said the Australian team's antibody study. And of Efstathiou and colleagues' finding that portions of CMV and HHV-6's sequences were 66 percent identical, Gallo and co-workers wrote that, "antigenic similarity resulting in cross-reactivity cannot be deduced from such DNA sequence similarity; that has to be proved experimentally." (43) In January 1990, a larger and apparently definitive report on the similarity CMV and HHV-6 was published in the Journal of Virology by a British research team led by G.L. Lawrence of Medical Research Council Laboratory of Molecular Research Council Laboratory of Molecular Biology (in Cambridge). In a long research report comparing the sequences of EBV, HCMV, herpes simplex virus (HSV), and varicella-zoster virus, these researchers, found that "HHV-6 is most closely related to HCMV." (44)

What is Martin's mystery "stealth" virus? Is it a new variant of HHV-6 -- now that HHV7 has been identified, is this HHV-8 or HHV-10? And what of its apparent retroviral characteristics? It is known that herpes viruses and retroviruses can interact, and even exchange genetic information. A 1992 research paper reported finding that "a retrovirus can integrate directly into a herpesvirus genome [genetic code]." These researchers, from Case Western Reserve University (Cleveland), even suggested that "These results raise the possibility that retroviral information may be transmitted by herpesvirus and that herpesvirus expression can be modulated by retroviral elements." (45) Gallo used this new information to further his hypothesis that HHV-6 is instrumental in causing immune system damage seen in "AIDS" via its interaction with HIV. He told Newsday, "It seems wherever HHV-6 is going, you're bound to bump into HIV. It's like cohabitation. So, therefore, I would give this [Case Western] paper very careful attention." (46)

Is Martin detecting an interaction between, say, HHV-6 and a retrovirus -- perhaps even an endogenous retrovirus? The answer to that question may have profound implications not only for CFS, but also for "AIDS."


1. Martin, W. John, Li Cheng Zeng, Khalid Ahmed, and Manju Roy; "Cytomegalovirus-Related Sequence in an Atypical Cytopathic Virus Repeatedly Isolated From a Patient With Chronic Fatigue Syndrome"; American Journal of Pathology 145(2), August 1994.

2. Ibid.

3. Martin et al., op. cit., 1994.

4. Jolly, Vik; "Virus Tied to Chronic Fatigue"; Orange County Register, August 8, 1994.

5. Martin, John; CFIDS Chronicle, Fall 1991.

8. Ibid.

9. Martin, op cit., Fall 1991.

10. Martin, op cit., Fall 1991.

11. Martin, op cit., Fall 1991.

12. Martin, op cit., Fall 1991.

12. Martin op cit., Fall 1991.

13. Winslow, Ron; "Chronic Fatigue Link to Virus Gains Support"; Wall Street Journal, September 23, 1991.

14. Altman, Lawrence K.; "Experts Unable to Link Chronic Fatigue to Virus"; Newsweek, September 30, 1991.

16. Altmank, op cit.

17. Cowley, op cit.

18. Martin, W. John; "Viral Infection in CFS Patients" in The Clinical and Scientific Basis of Chronic Fatigue Syndrome/ Myalgic Encephalomyelities, The Nightengale Research Foundation (Ottawa), 1992.

19. Martin et al., op cit., 1994.

20. Martin et al., op cit., 1994.

21. Martin et al., op cit., 1994.

22. Martin et al., op cit., 1994.

23. Martin et al., op cit., 1994.

24. Martin et al., op cit., 1994.

25. Martin et al., op cit., 1994.

25. Martin et al., op cit., 1994.

26. Martin et al., op cit., 1994.

27. Martin et al., op cit., 1994.

28. Martin et al., op cit., 1994.

29. Martin et al., op cit., 1994.

30. Martin et al., op cit., 1994.

31. Martin et al., op cit., 1994.

32. Martin et al., op cit., 1994.

33. Martin et al., op cit., 1994.

34. Lusso, Paolo et al.; "In Vitro Susceptibility of T Lymphocytes From Chimpanzees (Pan troglodytes ) to Human Herpesvirus 6 (HHV-6): A Potential Animal Model to Study the Interaction Between HHV-6 and Human Immunodeficiency Virus Type 1 In Vivo"; Journal of Virology , January 1990.

37. Efstathiou S. et al., "DNA Homology Between a Novel Human Herpesvirus (HHV-6) and Human Cytomegalovirus"; The Lancet , January 29, 1998.

38. Ibid.

39. Efstathiou et al., op cit.

40. Irving, William L. et al.; "Antibody to Both Human Herpesvirus 6 and Cytomegalovirus"; The Lancet , September 10, 1988.

41. Ibid.

42. Buchbinder, A. et al.; "Human Herpesvirus-6 and Crossreactivity With Other Herpesviruses"; The Lancet , January 28, 1989.

43. Ibid.

44. Lawrence et al., op cit.

45. Isfort, Robert et al.; "Retrovirus Insertion Into Herpesvirus In Vitro and In Vivo"; Proceedings of the National Academy of Sciences USA 89:991, February 1992.

46. Garrett, Laurie; "Viruses Swap Genetics in Cells"; New York Newsday , February 2, 1992.

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