Excerpts from the work of Dr. Richard Bowman PearceThe growing body of evidence is supporting the idea that parasitic disease may be an essential factor for AIDS. The theory was based upon three lines of evidence :
all the risk groups for AIDS had evidence for chronic "pan-immunosuppression" prior to HIV/AIDS
the epidemic of parasites in homosexuals preceded AIDS by a few years. That was a common factor with African and Haitian risk Groups.
parasites exert immunosuppressive, antigenic and mitogenic effects on T cells.
Between 80 and 100 percent of sexually active homosexual men worldwide are infected with one or more species of intestinal parasite.
The epidemic of parasites in gay men preceded AIDS by a few years.
In separate studies, the parasites gay men carry -- E. dispar (formerly E. histolytica), other so-called "nonpathological" amebae and Giardia -- have been shown to be specifically associated with a suppression of cell mediated immunity, elevation of IgM, depressed CD4:CD8 ratios, and increased risk for seroconversion to - and seropositivity for - HIV.
Parasites explain why AIDS develops among men and women alike in Africa and other tropical regions (Southeast Asia, the Caribbean, India) where parasites infect men and women indiscriminately. By contrast, in developed countries and urban settings, male homosexuals are the principal risk group for chronic parasite infection and AIDS.
Malaria appears to predispose to HIV in central and eastern Africa. Malaria has long been regarded as a co-factor for EBV-induced Burkitt's lymphoma.
E. histolytica extract activates latent HIV in T cells in culture. In mice, parasites activate HIV transgenes, depress anti-HIV and anti-adenoviral CTL activity, and promote a Th2 predominant state (which may favor retroviral replication). Mice with malaria are much more susceptible to leukemia caused by Moloney Murine Leukemia Virus than non-parasitized mice.
Logistic regression analyses of factors predisposing to KS in gay men show that the leading independent risk is exposure to feces. The intestinal parasites that colonize gay men are transmitted exclusively through the fecal-oral route. One early survey of Kaposi's Sarcoma in Africa showed an exact geographical confluence between KS and onchocerciasis, a chronic parasitic disease. Thus, the development of KS in gay men without HIV may be related to chronic immunodepression by parasites that permits the emergence of the KS associated herpes virus, HHV8.
Only feral cats that are parasitized naturally acquire FIV and develop feline AIDS. Pathogen-free cats do not transmit FIV when housed together, and when inoculated with FIV undergo an acute phase response but fail to develop feline AIDS characterized by severe CD4 depletion, opportunistic infection, and death.
Monkeys housed in the nation's primate centers, including those used in SIV studies, are universally infected with intestinal parasites and the animals in which the first reported cases of immunodeficiency appeared had been previously infected with malaria.
Cattle with trypanosomes are significantly more likely to be infected with Bovine Leukemia Virus (BLV) and to develop leukosis than parasite-free herds.
Progression to fulminant AIDS is more rare in groups such as sex partners of hemophiliacs and health care workers with occupational exposures to HIV than other risk groups whose immune systems are chronically activated. Such persons may seroconvert to HIV and/or develop anti-HIV cell-mediated activity, but lacking parasites or other chronic immune stimulus, do not progress to fulminant AIDS at the high rates observed in the major risk groups.
In 1987, it was predicted that HIV and AIDS would most likely spread by heterosexual transmission beyond Africa into other parasite endemic regions of the world, especially rural South America, Southeast Asia, and India. This, in fact, has occurred. If parasites were not an obligatory cofactor for AIDS, heterosexual transmission of HIV and AIDS would theoretically have occurred at an equally high rate in parasite-free regions of North America, Europe, and Australia. The comparatively low rate of HIV infection and AIDS progression among heterosexuals in these temperate regions is consistent with the idea that environmental cofactors are important determinants of HIV transmission and pathogenesis.
Not widely known is the fact that 80% or more of sexually active gay men currently carry Entamoeba dispar, E. coli, E. hartmanni, I. bütschlii, D. fragilis, and Giardia intestinalis among other protozoa (compared to an incidence in the general population of a 1-3%). The epidemic of parasites in gay men began in the mid 1970s and grew exponentially becoming pandemic in this group by 1979, a year or two before AIDS began to take its toll. E histolytica lectin stimulates HIV production in vitro while E. dispar and other "non-pathogenic" amebae in HIV(-) gay men are independently associated with skin anergy, chronically elevated IgM, and an increased risk for seroconversion to HIV.
In gay men, oral-anal contact is an independent risk factor for KS. KS can develop in HIV negative homosexual men, suggesting that some other immunodepressing agent besides HIV-1 can predispose to the putative KS virus, HHV8. This other source of immunodepression could be parasites since, in Uganda, KS (but not other tumors) has been found to be in exact and narrow geographical confluence with the chronic parasitic disease onchocerciasis. In Africa and other tropical areas as well as in Belle Glade, Florida, AIDS affects women as frequently as men.
In the U.S., between 1 and 2 million gay men are currently multiply infected with protozoa, yet very few are even aware of the fact. No other putative cofactor for AIDS, (e.g. mycoplasma, alcohol and drug abuse, HHV-6A) has such a uniformly high incidence rate in the gay and tropical risk groups for AIDS.
Epidemiological Association between Intestinal and Other Non-opportunistic Parasites and HIV/AIDS
Largely unappreciated, but by no means unknown, is the fact that 60% to 100% of sexually active gay men currently harbor one or more species of intestinal parasite, including Entamoeba dispar, E. coli, E. hartmanni, Iodamoeba butschlii, Dientamoeba fragilis, and Giardia intestinalis among others (Law et al, 1991, Esfandiari et al., 1995).
A recent surveillance for Giardia in New York City shows that the spread of this parasite through sexual means, i.e. as a STD among mostly gay men, continues to the present time. The highest rates are among hispanic children (mostly Dominican immigrants) and gay men, both HIV(+) and HIV(-) (NYC Department of Health, Ymilko@pppmail.nyser.net).
Like sexually active gay men, the tropical risk groups for AIDS also have a high prevalence of non-opportunistic parasites. In addition to enteric infections by nematodes and protozoa, these include schistosomiasis, strongyloidiasis, onchocerciasis and malaria (Climent, et al., 1994; Moore and Buster, 1984; Bouree, et al., 1995; Plumelle and Edouard, 1996).
The triad of HIV, non-opportunistic parasites, and AIDS is now reported for Haiti, the Republic of Congo (formerly Zaire), Uganda, Rwanda, Tanzania, Ethiopia, Puerto Rico, Jamaica, Martinique, Papua New Guinea, India, Pakistan, Southeast Asia, Belle Glade, Florida and South Los Angeles. Indeed, lymphotropic retroviruses, which require immune activation to reproduce successfully, may have co-evolved with parasites in the tropical regions of the world whence HIV and HTLV emerged.
Parasites Are Agents of Chronic Immunosuppression
Even the so-called "non-pathogenic" (i.e. non-invasive) ameba can depress cell-mediated immunity. They found that anergy significantly and independently associated with the presence of E. histolytica [now termed E. dispar], E. coli, and Iodamoeba bütschlii but not with other parasites.
more information:
http://www.dreddyclinic.com/integrated_med/parasites.htm
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