New research suggests that AIDS among humans occurred at least 3 decades earlier than previously thought. Rapid urbanization in west-central Africa “was the turning point that allowed the pandemic to start,” said Michael Worobey, an evolutionary biologist at the University of Arizona, Tucson, and the study’s lead author (Avasthi A. National Geographic News. October 1, 2008).
HIV/AIDS Emerged as Early as 1880s
New research suggests that AIDS among humans occurred at least 3 decades earlier than previously thought. Rapid urbanization in west-central Africa "was the turning point that allowed the pandemic to start," said Michael Worobey, an evolutionary biologist at the University of Arizona, Tucson, and the study's lead author (Avasthi A. National Geographic News. October 1, 2008).
Previous research has indicated that HIV-1, group M-globally, the most prevalent strain of the virus-originated in Cameroon in 1930 and began to reach epidemic levels in Lopoldville, Belgian Congo (now Kinshasa, Democratic Republic of the Congo), around 1960. The new study suggests that the virus was probably being transmitted among humans in sub-Saharan Africa between 1884 and 1924.
While analyzing tissue samples, the researchers took note of one sample from Kinshasa in 1960 that contained fragments of HIV-1 RNA. When they compared the 1960 virus with the oldest known strain of HIV-1, from 1959, they found significant differences. A mathematical model showed that at least 40 years of evolution must have elapsed to account for the differences between the 1960 and the 1959 strains. The most recent common ancestor of both strains can be traced to 1908, according to the model.
Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which funded the study with the NIH, said the finding "solidifies our understanding of the timetable of how this virus emerged from the chimpanzees to establish itself as a human infection." "This confirms that this was a virus that was lurking around for many decades before it exploded into the human population to become a noticeable pandemic, as opposed to something that started in the 70s or 80s," Fauci said.
Scientists see a clear understanding of the epidemic's origins as critical both to controlling HIV/AIDS and to responding to future emerging viruses. The report was published in Nature (Worobey M, Gemmel M, Teuwen DE, et al. Direct evidence of extensive diversity of HIV-1 in Kinshasa by 1960. Nature. 2008;455:661-664). [CDC HIV/Hepatitis/STD/TB Prevention News Update, Thursday, October 2, 2008]
Researchers Pan Abstinence-Only Sex Education
Studies published in a special issue of Sexuality Research & Social Policy enumerate numerous problems with abstinence-only sex education (United Press International. September 17, 2008). "Abstinence-only programs have a broad variety of problems with accuracy, efficacy, and ethics," said a statement by Dr John S. Santelli of Columbia University's Mailman School of Public Health, New York, who edited the issue. "These studies clearly demonstrate that federal promotion of abstinence has failed in its primary goal of helping young people delay initiation of sex and, actually, withholds lifesaving information from young people."
In one article, Douglas B. Kirby reviewed 56 studies: 8 that evaluated abstinence programs and 48 that evaluated comprehensive programs. "Study results indicated that most abstinence programs did not delay initiation of sex and only three of nine had any significant positive effects on any sexual behavior," Kirby noted. "In contrast, about two-thirds of comprehensive programs showed strong evidence that they positively affected young people's sexual behavior, including both delaying initiation of sex and increasing condom and contraceptive use among important groups of youth," Kirby wrote. "Based on this review, abstinence programs have little evidence to warrant their widespread replication; conversely, strong evidence suggests that some comprehensive programs should be disseminated widely."
The special issue was published in Sexuality Research & Social Policy (Santelli JS, Kantor LM, eds. Human rights, cultural, and scientific aspects of abstinence-only policies and programs. Sexuality Res Soc Policy. 2008;5(3):1-70). [CDC HIV/Hepatitis/STD/TB Prevention News Update, Friday, September 19, 2008]
One Out of Five Injecting Drug Users Worldwide Believed to Be HIV-Positive
New estimates by an international panel of experts calculate that nearly 16 million people in the world are injection drug users (IDUs), and about 20% of them are believed to be HIV-positive (Reuters Health. September 23, 2008).
The researchers, Dr Bradley M. Mathers of the University of New South Wales in Sydney, Australia, and colleagues from the 2007 Reference Group to the UN on HIV and Injecting Drug Use, reviewed published and online databases covering 200 nations or territories, of which 148 had information on drug injecting. Of these, 120 have reported HIV among IDUs. Their findings show that the extrapolated estimate suggests that 15.9 million people are IDUs, and the largest numbers of IDUs were found in China, the United States, and Russia, where mid-estimates of HIV prevalence among IDUs were 12%, 16%, and 37%, respectively. In 5 countries, HIV prevalence among IDUs ranged from 20% to 40%. In 9 countries-Estonia, Argentina, Brazil, Kenya, Myanmar, Indonesia, Thailand, Ukraine, and Nepal-HIV prevalence among IDUs was more than 40%. Worldwide, 3 million IDUs are believed to be HIV-positive.
"The number of countries in which the injection of drugs has been reported has increased over the last decade," the researchers concluded. "The high prevalence of HIV among many populations of [IDUs] represents a substantial global health challenge." The authors wrote that IDUs represent a population that has "fallen through the cracks" and is now driving the HIV epidemics in many parts of the world.
The report was published in The Lancet (Mathers BM, Degenhardt L, Phillips B, et al. Global epidemiology of injecting drug use and HIV among people who inject drugs: a systematic review. Lancet. 2008 Sep 23; [Epub ahead of print]. doi:10.1016/S0140-6736(08)61311-2). [CDC HIV/Hepatitis/STD/TB Prevention News Update, Wednesday, September 24, 2008]
New Institute to Focus on AIDS Vaccine
On Tuesday, researchers announced that a new HIV vaccine research center will open in California. The $30-million facility is a joint project of the Scripps Research Institute (SRI), based in La Jolla, Calif, and the International AIDS Vaccine Initiative (IAVI) (Fox M. Reuters. September 30, 2008).
"The world needs an AIDS vaccine to turn the tide on this devastating pandemic," SRI President Dr Richard Lerner said in a statement. "We are confident that this center will facilitate more productive exchanges among researchers and stimulate new ideas that will help to accelerate AIDS vaccine science."
The center will focus on how to stimulate neutralizing antibodies. Vaccines against HIV/AIDS have failed partly because the virus attacks the cells that are usually activated by immunization and partly because no vaccine has stimulated antibodies that kill the virus. "Finding a way to elicit neutralizing antibodies against HIV is the biggest challenge facing AIDS vaccine researchers today," said Dr Seth Berkley, president and CEO of IAVI.
The center will recruit biologists, virologists, chemists, and immunologists to work on clinical and laboratory research. "This reinvigorated approach will also make it easier for us to recruit and mentor the young scientists who represent the future of HIV/AIDS vaccine research," said Dennis Burton, who works at Scripps and IAVI. [CDC HIV/Hepatitis/STD/TB Prevention News Update, Wednesday, October 1, 2008]
Officials Call HIV Epidemic a Crisis
African Americans, Latinos, and men who have sex with men (MSM) are the groups hit hardest by the US HIV epidemic, and more must be done to protect them and educate them about the virus, the House Committee on Oversight and Government Reform was told on Tuesday. "We need to do so much more than we're doing right now," said Dr Julie Gerberding, director of the CDC. "And we need to get AIDS back on the radar screen. This is something that is still posing a threat to college students and to young men and women across our nation's fabric" (Dizikes C. Los Angeles Times. September 17, 2008).
The hearing followed the CDC's release last month of new data showing that earlier calculations had underestimated the number of new HIV infections in the nation each year by 40% for more than a decade. That estimate now stands at 56,300 new cases annually, not the 40,000 figure that had been cited for years. "The message these new findings sends is clear: We're not doing enough to limit the spread of this deadly disease," said Rep Henry Waxman (D-Calif), the committee's chair.
The total requested for HIV prevention in the US 2009 budget-$892 million, including $752.6 million requested by the CDC-is down slightly from the previous year. Based on the new data, Gerberding told the committee that the CDC would need $877 million more in 2009 and an additional $4.8 billion in the next 5 years. Waxman agreed to work with the Appropriations Committee to boost HIV prevention funding but said he was "not very optimistic" that additional money would be forthcoming under the current administration.
CDC figures show that the infection rates among blacks and Hispanics are 7 and 3 times higher, respectively, than the rate for whites. MSM accounted for 53% of new HIV infections in 2006. [CDC HIV/Hepatitis/STD/ TB Prevention News Update, Thursday, September 18, 2008]
Few HIV Patients Tested for Tuberculosis
An "unacceptable" 1% of HIV patients worldwide have been screened for tuberculosis (TB), researchers from the Advocacy to Control TB Internationally (ACTION) coalition said at the 17th International AIDS Conference in Mexico City (Vidya Shankar C. Reuters. August 8, 2008). According to the ACTION report, World Health Organization statistics show that just 314,394 of the 33 million people living with HIV/AIDS globally have been tested for TB. Of those screened, more than 1 in 4 were found to have active TB, said ACTION researchers.
"Persons living with HIV/AIDS are 50 times more likely to develop tuberculosis, than those who are HIV-negative," an ACTION release said. "Without treatment, approximately 90% of persons living with HIV/AIDS die within a few months of developing TB."
"One of the great tragedies of this epidemic is that people who are living with HIV, after hard-fought battles for access to antiretroviral treatment, go on to die needlessly from TB," said Dr Jim Yong Kim, chief of the division of social medicine and health inequalities at Harvard School of Medicine, Boston.
According to ACTION, TB screening is not mandatory in the programs funded by the top 3 international donors: the Global Fund to Fight AIDS, TB and Malaria; the US President's Emergency Plan for AIDS Relief; and the World Bank. The coalition is calling for an integrated approach to HIV/TB. All persons living with HIV/AIDS should be tested for TB and have access to the 3 "I's": intensified case finding, infection control, and isoniazid preventive therapy. [CDC HIV/Hepatitis/STD/TB Prevention News Update, Tuesday, August 12, 2008]
Effective HIV Therapy Improves Syphilis Serological Response Rates in HIV Patients
New research indicates that in patients coinfected with HIV and Treponema pallidum, highly active antiretroviral therapy reduces syphilis serological failure rates (Reuters Health. August, 19, 2008). "Syphilis and [HIV] frequently coexist in patients, but the effects of immunosuppression on the course of syphilis are unknown," wrote the study's authors, Dr Khalil G. Ghanem of Johns Hopkins University's Bayview Medical Center, Baltimore, and colleagues.
The team studied 231 cases of syphilis in 180 HIV-positive patients, who were followed up for a median of 5.3 years. There were 71 episodes of serological failure, defined as the lack of a 4-fold decrease in rapid plasma reagin titers 9 to 12 months after the initiation of therapy or a 4-fold increase in titers 30 days after the initiation of therapy.
A CD4+ cell count below 200/µL increased the risk of serological failure (adjusted hazard ratio [AHR], 2.48). Receipt of antiretroviral therapy for more than 6 months significantly reduced this risk (AHR, 0.40), independent of concomitant CD4 responses. Patients who had a 50% increase in CD4 count from baseline saw an 82% reduction in risk of serological failure, compared with a 52% reduction for patients receiving antiretroviral therapy who did not achieve an immunological response. During follow-up, the team noted a 2% decrease in serological failure for every week of use of macrolides, chiefly azithromycin.
"Given that syphilis serological failures and neurosyphilis occur in patients with more advanced immunosuppression, immune reconstitution using [antiretroviral therapy] appears to be a reasonable additional intervention to try and limit poor outcomes in HIV and syphilis coinfected patients," Ghanem said.
The report was published in Clinical Infectious Diseases (Ghanem KG, Moore RD, Rompalo AM, et al. Antiretroviral therapy is associated with reduced serologic failure rates for syphilis among HIV-infected patients" (Clin Infect Dis. 2008;47:258-265). [CDC HIV/Hepatitis/ STD/TB Prevention News Update, Wednesday, August 20, 2008]
HIV Treatment May Provoke Asthma in Kids
A new study shows that highly active antiretroviral therapy may increase the risk of asthma in young children (Gale K. Reuters. August 26, 2008). Dr William T. Shearer of the Texas Children's Hospital in Houston and colleagues studied the rate of asthma in children born to HIV-positive mothers, comparing 193 children infected with HIV (113 treated with antiretroviral therapy and 80 never treated with antiretroviral therapy) and 2471 HIV-negative children.
The rate of asthma medication use in antiretroviral-treated children by age 13.5 years was 33.5%, compared with 11.5% in HIV-infected children not treated with antiretroviral therapy. Since the rate in antiretroviral-treated children was just slightly higher than that in HIV-negative children, the researchers suggested that untreated HIV infection may actually protect against asthma. Further analysis showed the increase in T-cell levels achieved with antiretroviral therapy was to blame for the elevated asthma risk.
"Investigators have assumed that asthma is not a complication of pediatric HIV infection, because studies [conducted before antiretroviral therapy was introduced in the mid-1990s] did not detect the problem," explained Shearer. The reason was that without antiretroviral therapy, the number of T cells would drop, preventing an asthmatic reaction, he noted. "It was not until the era of HAART, which restored the [T cell] levels, that an increased incidence of asthma was noted." Until additional studies verify the researchers' findings, Shearer cautioned physicians to be alert to the possibility that antiretroviral therapy may lead to asthma in children. Parents should also be made aware of this possible adverse outcome, he said.
The report of the study was published in the Journal ofAllergy and Clinical Immunology (Foster SB, McIntosh K, Thompson B, et al. Increased incidence of asthma in HIV-infected children treated with highly active antiretroviral therapy in the National Institutes of Health Women and Infants Transmission Study. J Allergy Clin Immunol. 2008;122:159-165). [CDC HIV/Hepatitis/STD/TB Prevention News Update, Tuesday, September 2, 2008]
Circumcision Problems Impair HIV Prevention
Results of a World Health Organization (WHO) study released in September raise doubts about the rapid implementation of male circumcision as a strategy to fight HIV/AIDS in Africa, where researchers found "shocking" rates of complications from the procedure (MacInnis L. Reuters. September 1, 2008). Studies have shown that male circumcision reduces the risk of female-to-male HIV transmission by up to 70%.
The WHO study authors, Kenyan Omar Egesah and Robert Bailey, and Stephanie Rosenberg of the United States, found that as many as 35% of males circumcised by traditional practitioners in Kenya's Bungoma district had complications, including bleeding, infection, excessive pain, and erectile dysfunction. "Other common adverse effects reported were pain upon urination, incomplete circumcision requiring recircumcision, and laceration," said the authors, estimating that 6% of patients had lifelong problems as a result.
The researchers physically examined 298 of the 1007 participants in the study; they intervened when they observed complications. While male circumcision is universally practiced in Bungoma, the study indicated that many clinicians there lacked sharp and sterile instruments and few were formally trained. Even public clinics had a complication rate of 18%.
The study's findings "should serve as an alarm to ministries of health and the international health community that focus cannot only be on areas where circumcision prevalence is low," said the authors. "Extensive training and resources will be necessary to build the capacity of health facilities in sub-Saharan Africa before safe circumcision services can be aggressively promoted for HIV prevention," they wrote.
The results of the study were published in the Bulletin of the World Health Organization (Bailey RC, Egesah O, Rosenberg S. Male circumcision for HIV prevention: a prospective study of complications in clinical and traditional settings in Bungoma, Kenya. Bull World Health Organ. 2008;86:657-736). [CDC HIV/Hepatitis/STD/TB Prevention News Update, Wednesday, September 3, 2008]
Male Circumcision Could Be Even Greater Boon Than Thought
Circumcision may offer even more protection against female-to-male HIV transmission than previously revealed, as well as partial protection against human papillomavirus (HPV), researchers said at the 17th International AIDS Conference (Ingham R. Agence France Presse. August 8, 2008). Among 2784 men who were randomly circumcised or not in a study in Kisumu, Kenya, those circumcised were 60% less likely to have acquired HIV than uncircumcised men at 24 months.
The intervention was so successful that all uncircumcised men in the trial were offered the procedure. And at 42 months, among the 1739 participants remaining in the trial, protection was 65%, Robert Bailey of the University of Illinois–Chicago told the conference. "These results further support the addition of male circumcision to our limited armamentarium of HIV prevention," Bailey said.
In another presentation, researcher Dirk Taljaard reported findings indicating that males in the randomized circumcision trial in Orange Farm, South Africa, were 36% less likely to acquire HPV than uncircumcised participants. In addition, circumcision conferred "borderline" protection from the parasitic organism Trichomonas vaginalis. It offered no protection against Neisseria gonorrhoeae, however. [CDC HIV/Hepatitis/STD/TB Prevention News Update, Friday, August 8, 2008]
Parasitic Worms May Help Fuel AIDS Epidemic
New findings suggest that people infected with the parasitic worm that causes schistosomiasis may be much more susceptible to infection with HIV (Dunham W. Reuters. July 22, 2008). Schistosomiasis is found mostly in developing countries with unsanitary water supplies, and the new evidence may help explain why sub-Saharan Africa has been disproportionately affected by HIV.
In this study, scientists worked with 2 groups of rhesus monkeys: some had acute infection with the Schistosoma mansoni parasitic worm, while others were parasite-free and healthy. All the monkeys were then rectally exposed to a hybrid of HIV and simian immunodeficiency virus. The amount of virus needed to cause HIV infection in the monkeys given the parasite was 17 times lower than the amount needed to infect the healthy monkeys. Dr Ruth Ruprecht of Harvard Medical School, Boston, one of the researchers, said that in addition to becoming infected more easily, the monkeys carrying the parasite had much higher concentrations of virus in their blood, meaning they were more infectious. "If the virus is extremely high in the blood, then the chances are that the virus is also going to be high in the genital fluids. And therefore such a host would be more likely to be spreading the infection to others," she said. The CDC's Evan Secor, another of the researchers, said the findings probably apply to humans as well.
These flatworms live in snail-infested freshwater bodies and bore through the skin to travel through the bloodstream. Schistosomiasis is treatable with the drug praziquantel, and Ruprecht said the findings underscore the need to control the worm in areas where HIV is prevalent.
The report was published in Public Library of Science Neglected Tropical Diseases (Chenine AL, Shai-Kobiler E, Steele LN, et al. Acute Schistosoma mansoni infection increases susceptibility to systemic SHIV clade C infection in rhesus macaques after mucosal virus exposure. PloS Negl Trop Dis. 2008;2:e265 doi:10.1371/journal/pntd. 0000265). [CDC HIV/Hepatitis/STD/TB Prevention News Update, Wednesday, August 13, 2008]
Behavioral Approaches Overlooked in HIV Prevention
According to AIDS experts at the 17th International AIDS Conference held in August in Mexico City, not enough is being done to use behavioral approaches to prevent HIV infections worldwide. They recommended combining measures such as delayed intercourse, condom use, decreasing drug abuse, needle exchange programs, and male circumcision to combat HIV globally (Altman LK. New York Times. August 6, 2008). The Global HIV Prevention Working Group, a 50-member panel supported by the Bill & Melinda Gates Foundation, released a report saying that efforts must address a number of perception problems regarding HIV prevention.
According to the Gates report, one problem is misplaced pessimism about the effectiveness of HIV prevention strategies. Another is confusing the difficulty in changing human behavior with an inability to do so. Finally, there is the misperception that because it is inherently difficult to measure prevention success, these efforts have no impact.
At the conference, AIDS experts said a pressing need exists to combine HIV prevention and treatment efforts. Researchers involved in each field "need to get married today," said Dr Myron S. Cohen of the University of North Carolina, Chapel Hill. "We need to be one community." The experts added that characteristics of the global epidemic varied greatly among and within countries, most of which were not focusing prevention resources where their epidemics were concentrated.
Dr Jorge Saavedra, who directs Mexico's HIV/AIDS program, said national AIDS responses need to involve more gay and bisexual men in planning ways to reach high-risk individuals. [CDC HIV/Hepatitis/STD/TB Prevention News Update, Wednesday, August 6, 2008]