Tuesday, May 19, 2009
New Virus in American
A novel flu virus has struck hundreds of people in Mexico, and at least 18 have died. It has also infected 20 people in five states in the US, and appears able to spread readily from human to human. The US has declared a public health emergency, and the World Health Organization is holding emergency meetings to decide whether to declare the possible onset of a flu pandemic.
Ironically, after years of concern about H5N1 bird flu, the new flu causing concern is a pig virus, of a family known as H1N1.
Flu viruses are named after the two main proteins on their surfaces, abbreviated H and N. They are also differentiated by what animal they usually infect. The H in the new virus comes from pigs, but some of its other genes come from bird and human flu viruses, a mixture that the US Centers for Disease Control and Prevention calls "very unusual".
On Wednesday, the CDC announced that routine surveillance had uncovered mild flu cases during late March and April, caused by a novel swine flu virus. Those affected, aged 9 to 54, live in and around San Diego, California, and San Antonio, Texas, near the Mexican border. None was severe. Symptoms were normal for flu, with more nausea and diarrhoea than usual.
Mongrelised mix
On Thursday, Canadian public health officials warned Canadians travelling to Mexico of clusters of severe flu-like illness there. Then on Friday the WHO in Geneva said in a statement there have been around 900 suspected cases of swine flu in Mexico City and two other regions of Mexico, with around 60 suspected deaths. Of those, 18 have been confirmed as H1N1 swine flu, says the WHO, and tests so far have shown that 12 of those are "genetically identical" to the California virus.
On Friday, Richard Besser, head of the CDC, confirmed that Mexican samples tested at CDC were also "similar" to the US virus. "From everything we know to date, this virus appears to be the same," he said.
On Saturday and Sunday, the CDC confirmed eight cases of swine flu had been confirmed at a girl's school in New York, two cases in Kansas and a case in Ohio.
To be declared a pandemic, Besser said, the virus must be new, cause severe disease, and transmit easily enough to be sustained.
It is new. Anne Schuchat, head of science and public health at the CDC, said that the US virus is an unusually mongrelised mix of genetic sequences from North American pigs, Eurasian pigs, birds and humans. The H protein on its surface, having hitherto circulated only in pigs, is one most human immune systems have never seen, the crucial requirement for a pandemic flu.
Too late to contain
The "case mortality" of swine flu – how many people die after being infected – is not yet known. While suspect deaths in Mexico are being tested for H1N1, we don't know how many mild cases of virus there may have been in the affected region that have gone untested. Both numbers are needed to calculate how deadly a pandemic might be. One ominous sign, however, is that the Mexican cases are said to be mainly young adults, a hallmark of pandemic flu.
It can transmit among people. Those infected in the US had no known contact with pigs, and the three separate clusters of cases did not contact each other. This suggests, said Besser, that "this virus has already been transmitted from person to person, for several cycles", making it too late for emergency antiviral drugs to contain its spread to a limited area.
'High concern'
"Because there are human cases associated with an animal influenza virus, and because of the geographical spread of multiple community outbreaks, plus the somewhat unusual age groups affected, these events are of high concern," the WHO said.
CDC scientists are now examining people with current and recent flu-like illnesses in the areas affected to see how many contacts of known cases have traces of the virus, or antibodies to it. That should show how many cases there may have been, how readily the virus spreads, and how likely it is to maintain transmission. On Sunday Besser said that contacts of people diagnosed with the virus "have significant rates of respiratory infection", suggesting it may be easily communicable.
Another H1N1 flu jumped from pigs to people in 1976, and killed an army recruit in New Jersey. The US went on high alert and vaccinated thousands of people – but the virus did not spread readily enough to maintain an epidemic, and fizzled out.
Friday, February 13, 2009
Chlamydia
Chlamydia Infection
What is chlamydia?
Chlamydia is a common sexually transmitted disease (STD) caused by the bacterium, Chlamydia trachomatis, which can damage a woman's reproductive organs. Even though symptoms of chlamydia are usually mild or absent, serious complications that cause irreversible damage, including infertility, can occur "silently" before a woman ever recognises a problem. Chlamydia also can cause discharge from the penis of an infected man.
How common is chlamydia?
Chlamydia is the most frequently reported bacterial sexually transmitted disease in the United States. In 2002, 834,555 chlamydial infections were reported to CDC from 50 states and the District of Columbia. Under-reporting is substantial because most people with chlamydia are not aware of their infections and do not seek testing. Also, testing is not often done if patients are treated for their symptoms. An estimated 2.8 million Americans are infected with chlamydia each year. Women are frequently re-infected if their sex partners are not treated.
How do people get chlamydia?
Chlamydia can be transmitted during vaginal, anal, or oral sex. Chlamydia can also be passed from an infected mother to her baby during vaginal childbirth.
Any sexually active person can be infected with chlamydia. The greater the number of sex partners, the greater the risk of infection. Because the cervix (opening to the uterus) of teenage girls and young women is not fully matured, they are at particularly high risk for infection if sexually active. Since chlamydia can be transmitted by oral or anal sex, men who have sex with men are also at risk for chlamydial infection.
What are the symptoms of chlamydia?
Chlamydia is known as a "silent" disease because about three quarters of infected women and about half of infected men have no symptoms. If symptoms do occur, they usually appear within 1 to 3 weeks after exposure.
In women, the bacteria initially infect the cervix and the urethra (urine canal). Women who have symptoms might have an abnormal vaginal discharge or a burning sensation when urinating. When the infection spreads from the cervix to the fallopian tubes (tubes that carry eggs from the ovaries to the uterus), some women still have no signs or symptoms; others have lower abdominal pain, low back pain, nausea, fever, pain during intercourse, or bleeding between menstrual periods. Chlamydial infection of the cervix can spread to the rectum.
Men with signs or symptoms might have a discharge from their penis or a burning sensation when urinating. Men might also have burning and itching around the opening of the penis. Pain and swelling in the testicles are uncommon.
Men or women who have receptive anal intercourse may acquire chlamydial infection in the rectum, which can cause rectal pain, discharge, or bleeding. Chlamydia can also be found in the throats of women and men having oral sex with an infected partner.
What complications can result from untreated chlamydia?
If untreated, chlamydial infections can progress to serious reproductive and other health problems with both short-term and long-term consequences. Like the disease itself, the damage that chlamydia causes is often "silent."
In women, untreated infection can spread into the uterus or fallopian tubes and cause pelvic inflammatory disease (PID). This happens in up to 40 percent of women with untreated chlamydia. PID can cause permanent damage to the fallopian tubes, uterus, and surrounding tissues. The damage can lead to chronic pelvic pain, infertility, and potentially fatal ectopic pregnancy (pregnancy outside the uterus). Women infected with chlamydia are up to five times more likely to become infected with HIV, if exposed.
To help prevent the serious consequences of chlamydia, screening at least annually for chlamydia is recommended for all sexually active women age 25 years and younger. An annual screening test also is recommended for older women with risk factors for chlamydia (a new sex partner or multiple sex partners). All pregnant women should have a screening test for chlamydia.
Complications among men are rare. Infection sometimes spreads to the epididymis (a tube that carries sperm from the testis), causing pain, fever, and, rarely, sterility.
Rarely, genital chlamydial infection can cause arthritis that can be accompanied by skin lesions and inflammation of the eye and urethra (Reiter's syndrome).
How does chlamydia affect a pregnant woman & her baby?
In pregnant women, there is some evidence that untreated chlamydial infections can lead to premature delivery. Babies who are born to infected mothers can get chlamydial infections in their eyes and respiratory tracts. Chlamydia is a leading cause of early infant pneumonia and conjunctivitis (pink eye) in newborns.
How is chlamydia diagnosed?
There are laboratory tests to diagnose chlamydia. Some can be performed on urine, other tests require that a specimen be collected from a site such as the penis or cervix.
What is the treatment for chlamydia?
Chlamydia can be easily treated and cured with antibiotics. A single dose of azithromycin or a week of doxycycline (twice daily) are the most commonly used treatments. HIV-positive persons with chlamydia should receive the same treatment as those who are HIV negative.
All sex partners should be evaluated, tested, and treated. Persons with chlamydia should abstain from sexual intercourse until they and their sex partners have completed treatment, otherwise re-infection is possible.
Women whose sex partners have not been appropriately treated are at high risk for re-infection. Having multiple infections increases a woman's risk of serious reproductive health complications, including infertility. Retesting should be considered for women, especially adolescents, three to four months after treatment. This is especially true if a woman does not know if her sex partner received treatment.
How can chlamydia be prevented?
The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual contact, or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected.
Latex male condoms, when used consistently and correctly, can reduce the risk of transmission of chlamydia.
Chlamydia screening is recommended annually for all sexually active women 25 years of age and younger. An annual screening test also is recommended for older women with risk factors for chlamydia (a new sex partner or multiple sex partners). All pregnant women should have a screening test for chlamydia.
Any genital symptoms such as discharge or burning during urination or unusual sore or rash should be a signal to stop having sex and to consult a health care provider immediately. If a person has been treated for chlamydia (or any other STD), he or she should notify all recent sex partners so they can see a health care provider and be treated. This will reduce the risk that the sex partners will develop serious complications from chlamydia and will also reduce the person's risk of becoming re-infected. The person and all of his or her sex partners must avoid sex until they have completed their treatment for chlamydia.
What is chlamydia?
Chlamydia is a common sexually transmitted disease (STD) caused by the bacterium, Chlamydia trachomatis, which can damage a woman's reproductive organs. Even though symptoms of chlamydia are usually mild or absent, serious complications that cause irreversible damage, including infertility, can occur "silently" before a woman ever recognises a problem. Chlamydia also can cause discharge from the penis of an infected man.
How common is chlamydia?
Chlamydia is the most frequently reported bacterial sexually transmitted disease in the United States. In 2002, 834,555 chlamydial infections were reported to CDC from 50 states and the District of Columbia. Under-reporting is substantial because most people with chlamydia are not aware of their infections and do not seek testing. Also, testing is not often done if patients are treated for their symptoms. An estimated 2.8 million Americans are infected with chlamydia each year. Women are frequently re-infected if their sex partners are not treated.
How do people get chlamydia?
Chlamydia can be transmitted during vaginal, anal, or oral sex. Chlamydia can also be passed from an infected mother to her baby during vaginal childbirth.
Any sexually active person can be infected with chlamydia. The greater the number of sex partners, the greater the risk of infection. Because the cervix (opening to the uterus) of teenage girls and young women is not fully matured, they are at particularly high risk for infection if sexually active. Since chlamydia can be transmitted by oral or anal sex, men who have sex with men are also at risk for chlamydial infection.
What are the symptoms of chlamydia?
Chlamydia is known as a "silent" disease because about three quarters of infected women and about half of infected men have no symptoms. If symptoms do occur, they usually appear within 1 to 3 weeks after exposure.
In women, the bacteria initially infect the cervix and the urethra (urine canal). Women who have symptoms might have an abnormal vaginal discharge or a burning sensation when urinating. When the infection spreads from the cervix to the fallopian tubes (tubes that carry eggs from the ovaries to the uterus), some women still have no signs or symptoms; others have lower abdominal pain, low back pain, nausea, fever, pain during intercourse, or bleeding between menstrual periods. Chlamydial infection of the cervix can spread to the rectum.
Men with signs or symptoms might have a discharge from their penis or a burning sensation when urinating. Men might also have burning and itching around the opening of the penis. Pain and swelling in the testicles are uncommon.
Men or women who have receptive anal intercourse may acquire chlamydial infection in the rectum, which can cause rectal pain, discharge, or bleeding. Chlamydia can also be found in the throats of women and men having oral sex with an infected partner.
What complications can result from untreated chlamydia?
If untreated, chlamydial infections can progress to serious reproductive and other health problems with both short-term and long-term consequences. Like the disease itself, the damage that chlamydia causes is often "silent."
In women, untreated infection can spread into the uterus or fallopian tubes and cause pelvic inflammatory disease (PID). This happens in up to 40 percent of women with untreated chlamydia. PID can cause permanent damage to the fallopian tubes, uterus, and surrounding tissues. The damage can lead to chronic pelvic pain, infertility, and potentially fatal ectopic pregnancy (pregnancy outside the uterus). Women infected with chlamydia are up to five times more likely to become infected with HIV, if exposed.
To help prevent the serious consequences of chlamydia, screening at least annually for chlamydia is recommended for all sexually active women age 25 years and younger. An annual screening test also is recommended for older women with risk factors for chlamydia (a new sex partner or multiple sex partners). All pregnant women should have a screening test for chlamydia.
Complications among men are rare. Infection sometimes spreads to the epididymis (a tube that carries sperm from the testis), causing pain, fever, and, rarely, sterility.
Rarely, genital chlamydial infection can cause arthritis that can be accompanied by skin lesions and inflammation of the eye and urethra (Reiter's syndrome).
How does chlamydia affect a pregnant woman & her baby?
In pregnant women, there is some evidence that untreated chlamydial infections can lead to premature delivery. Babies who are born to infected mothers can get chlamydial infections in their eyes and respiratory tracts. Chlamydia is a leading cause of early infant pneumonia and conjunctivitis (pink eye) in newborns.
How is chlamydia diagnosed?
There are laboratory tests to diagnose chlamydia. Some can be performed on urine, other tests require that a specimen be collected from a site such as the penis or cervix.
What is the treatment for chlamydia?
Chlamydia can be easily treated and cured with antibiotics. A single dose of azithromycin or a week of doxycycline (twice daily) are the most commonly used treatments. HIV-positive persons with chlamydia should receive the same treatment as those who are HIV negative.
All sex partners should be evaluated, tested, and treated. Persons with chlamydia should abstain from sexual intercourse until they and their sex partners have completed treatment, otherwise re-infection is possible.
Women whose sex partners have not been appropriately treated are at high risk for re-infection. Having multiple infections increases a woman's risk of serious reproductive health complications, including infertility. Retesting should be considered for women, especially adolescents, three to four months after treatment. This is especially true if a woman does not know if her sex partner received treatment.
How can chlamydia be prevented?
The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual contact, or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected.
Latex male condoms, when used consistently and correctly, can reduce the risk of transmission of chlamydia.
Chlamydia screening is recommended annually for all sexually active women 25 years of age and younger. An annual screening test also is recommended for older women with risk factors for chlamydia (a new sex partner or multiple sex partners). All pregnant women should have a screening test for chlamydia.
Any genital symptoms such as discharge or burning during urination or unusual sore or rash should be a signal to stop having sex and to consult a health care provider immediately. If a person has been treated for chlamydia (or any other STD), he or she should notify all recent sex partners so they can see a health care provider and be treated. This will reduce the risk that the sex partners will develop serious complications from chlamydia and will also reduce the person's risk of becoming re-infected. The person and all of his or her sex partners must avoid sex until they have completed their treatment for chlamydia.
Subscribe to:
Comments (Atom)
