News (Updated January 14,
2007)
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| Friday January 12, 10:50 AM |
Syphilis back with a vengeance in China - reportHONG KONG (Reuters) - Syphilis, which was largely eliminated in China between 1960 and 1980, has returned with a vengeance and urgent intervention is needed to curb the epidemic, according to researchers in China and the United States.In a study to be published in the January 13 issue of the Lancet, they said the total incidence of syphilis in China increased to 6.5 cases per 100,000 people in 1999 from less than 0.2 cases per 100,000 in 1993. "Syphilis has returned to China with a vengeance. The data demonstrates a syphilis epidemic of such scope and magnitude that it will require terrific effort to intervene," said lead researcher Myron S. Cohen, director of the Centre for Infectious Diseases at the University of North Carolina at Chapel Hill School of Medicine. When the Communist Party took power in 1949, China was suffering one of the biggest syphilis epidemics in human history and the government launched a prolonged campaign to eliminate sexually transmitted diseases. The study linked the re-emergence of syphilis to economic reforms and globalisation in China. "These changes have led to income gaps and a cultural climate that favours re-emergence of prostitution due to a substantial majority of men and a large migrant population of male workers," the report said. "Changing social practices such as people experimenting with sex at earlier ages and before marriage, as well as increasing costs of individual health care, also contribute." Of the three categories of disease - primary, secondary and tertiary - the first two represented 5.7 cases per 100,000 people in 2005. This latter incidence is substantially higher than in most developed countries, including the U.S., which reported 2.7 cases per 100,000 of primary and secondary syphilis in 2004. The researchers based their report on data collected from China's national sexually transmitted disease (STD) surveillance system and sentinel site network. Also alarming is the rate of congenital syphilis, Cohen said, which increased to 19.68 cases per 100,000 live births in 2005 from 0.01 cases in 1991 - an average yearly rise of 71.9 percent. Congenital syphilis occurs when a pregnant woman with syphilis passes the infection to her baby in the womb. Many cases result in miscarriage or stillbirth, and surviving babies may have serious problems with the brain, liver, and other organs. By 1964, syphilis had become rare and was virtually absent for the next 20 years. However, that means the general population of young, sexually active individuals has no natural immunity to the disease. "Sexually active individuals would be completely susceptible to this infection," the report said, noting that syphilis increases the risk of both transmitting and getting infected with HIV, the virus that causes AIDS. Syphilis can be treated with antibiotics. Left untreated, it can cause serious damage to the nervous system, heart or brain, and can be fatal. |
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They mapped the genome of Trichomonas vaginalis, which causes the most common non-viral sexually transmitted infection, and hope they have found a few chinks in its armor.
Trichomonas, often called "trick", affects at least 170 million people globally. It is not only itchy and unpleasant, but can infect newborns, cause preterm births and small babies.
It also makes women more vulnerable to the AIDS virus, gonorrhea and syphilis and, unlike many other sexually transmitted infections, can in rare instances be transmitted by wet towels or toilet seats.
While it can be irritating to men, and is passed along by both sexes, women suffer more, said Dr. Jane Carlton of the New York University School of Medicine, who led the study.
"If men had itchy penises I reckon this disease would have a lot more money thrown at it than it has. It is thought of as a woman's disease," Carlton said in a telephone interview.
Her team of 66 researchers in 10 countries found the little protozoan has an exceptionally large collection of DNA, with close to 26,000 confirmed genes -- nearly as many as the human genome.
"It was a huge shock," said Carlton, who led the study while at The Institute for Genomic Research in Maryland.
Researchers are not sure why, but believe it may have something to do with helping the pear-shaped organism infect the urogenital tract.
Only two drugs, both in the same class, are approved for treating Trichomoniasis infections, which can be symptom-less for years and then break out unexpectedly with a vengeance. The microbe is already resistant to one of the drugs, the researchers aid.
FINDING CHINKS
But examination of the gene map shows some weaknesses, and also some good ways to perhaps identify it more easily and earlier in patients.
"We found a few chinks in the armor," said Carlton, whose work was funded by the National Institute of Health.
Another surprise -- it contains genes that appear to have been passed to the organism from bacteria.
Some of these genes allow Trichomonas to synthesize the amino acid cysteine, which in turn allows it to control the effects of oxygen in the environment.
It is by manipulating the environment that Trichomonas does much of its damage, Carlton said.
"The pH shifts towards more alkaline and that makes the vaginal environment not as healthy," she said. An alkaline environment allows HIV and other sexually transmitted infections to take hold more easily.
And the little microbe itself looks and acts in complex ways.
"The organism is really funky to look at," Carlton said. It has four flagella sprouting from its apex, a tail, and an "undulating membrane which like a frilly nightgown," she said.
It flattens itself and sticks tendrils into the wall of the vagina or urethra, Carlton said.
"It starts to secrete a lot of nasty proteases and pore-forming proteins to degrade vaginal tissue," she said.
"It produces hydrogen. That is probably what produces the gray-green frothy discharge from women."
And it makes other gases that may cause the characteristic fishy odor, as well, she said.
BOSTON, Jan 10 (Reuters) - Pregnant women who are HIV-positive and take the drug nevirapine during labor to prevent infecting their babies should wait until six months after delivery to resume taking the drug to avoid developing resistance, a new study showed.
By following the findings, to be published in The New England Journal of Medicine on Thursday, mothers could reduce the chance of the AIDS drug failing to work when they need it for themselves.
It translates into very clear policy for how to treat AIDS in new mothers who received nevirapine to protect their infants, said Max Essex, an author of the study, which followed the cases of 218 women in Botswana.
The study will be most important in poor countries where nevirapine-based therapy may be the only treatment available to shield a baby from the AIDS virus during delivery.Once the drug is used, the risk of an already infected mother developing resistance to it is high.
Up to 69 percent of the women who receive a single dose of the drug discover that the AIDS virus quickly develops a resistance to it. In cases where the drug fails to protect the baby, the infant can develop a resistance as well.
But if the virus doesn't see nevirapine for six months after the initial dose, the drug retains its effectiveness, said Essex of the Harvard School of Public Health.
Nearly 42 percent of the women who started receiving nevirapine within six months of their baby's delivery developed a resistance to the drug, compared to 12 percent who did not receive it until at least six months after delivery.
The drug is often given as a combination, known as ART.
"If you can wait six months to administer nevirapine-based ART, do so," said Essex. "If not, treat only with combinations of drugs that do not contain nevirapine or nevirapine-related drugs. Implementing this policy can improve the health of women who need AIDS treatment."
Nevirapine is sold under the brand name Viramune by the privately held Boehringer Ingelheim.
Tuesday January 9, 8:47 AM
Detecting whether patients with HIV/AIDS are infected with even small amounts of drug-resistant forms of the virus can be done with a test developed by researchers at Duke University Medical Center.
While other tests only pick up drug-resistant strains when they represent a significant portion of the virus in a person's bloodstream, the test developed at Duke may enable doctors to more accurately predict which medicines will work for patients and which drugs will ultimately fail.
"This can be huge," said Dr. Feng Gao, a Duke HIV/AIDS researcher and co-author of the article published online Sunday in the journal Nature Methods.
So far, the test has been used for research purposes only. Duke is seeking patents that will enable it to develop a diagnostic screening for future commercial use.
A private industry backer is still needed, along with other studies that demonstrate the process helps improve treatment outcome.
Duke's new test comes amid rising evidence that HIV drug-resistance is a problem, even among patients who have never been treated with antiretroviral drugs. Studies have found that 15 percent or more of patients newly diagnosed with HIV harbor drug-resistant strains of the virus.
"A lot of questions are still unanswered, but it's an important step forward," said Dr. Peter Leone, an HIV/AIDS doctor at the University of North Carolina at Chapel Hill and medical director of the state's HIV prevention branch.
If the test pans out, Leone said, it would "improve the odds that the first course of treatment is going to be successful."
Even the less sensitive tests available now are helpful in avoiding treatment pitfalls, said Dr. Charles Hicks, a Duke infectious disease specialist who treats patients with HIV/AIDS and is co-author on the journal article.
He says a common mutant strain picked up by such tests resists one of the first-line treatments for HIV, and if patients test positive for that type of drug-resistant strain, doctors know to prescribe other medicines.
"It makes you choose a totally different treatment path," Hicks said.
Duke's test is more sensitive and detects resistant strains that make up less than 1 percent of the virus circulating in the patient's blood. With existing tests, drug-resistant HIV strains are picked up only if they make up 20 percent or more of the total virus in the patient's system.
"Even if you don't see resistance, you can't be sure that it's not really there," Hicks said. "That's a huge problem."