15 September News

Outbreak of Pigborne Bacterial Infection Worsens in China

28 July (Reuters Health)—The number of people infected by what Chinese authorities believe is a pigborne bacterial disease has jumped by 14 to 131, state media said as officials insisted the outbreak could be controlled.

The World Health Organization said it is watching developments closely, but a spokesman said the disease appears to be localized and poses no threat internationally.

Streptococcus suis, known as swine flu, is endemic in swine in most pig-rearing countries in the world, but human infections are rare. Although China's state media has said no human-to-human infections have been found in Sichuan, the death toll is considered unusually high.

Swine flu is not known to have ever been passed between humans, but scientists fear it could mutate into a strain that could easily pass among people and unleash an epidemic.

The unusually high mortality and reports that many of the victims died within 24 h of showing symptoms have led some experts to wonder if it is indeed swine flu at all. “It could be another disease altogether, it need not be S. suis because the presentation is so atypical,” said Samson Wong, a microbiology associate professor at the University of Hong Kong.

The China Daily said China had vaccines against the bacteria, and 2 factories resumed production recently. The vaccine had not been produced for years due to a lack of demand, it said.

The last time swine flu broke out in China in a significant way was in 1998, when 22 people were infected, Dietz said, adding that Chinese scientists were convinced they were now dealing with the same strain of bacteria.

Editor's comment. As of 29 July, there have been 152 cases of pigborne bacterial disease, with 31 deaths reported. S. suis is a commensal organism, commonly found in pigs, that can cause invasive disease. Humans at risk are those with exposure to pigs or to products from pigs. The infection may be more virulent in persons who are asplenic. The most common manifestation of human S. suis infection is meningitis. Primary bacteremia, endocarditis, septic arthritis, and pneumonia have been reported. A clinical picture similar to that of toxic shock syndrome has been described in human S. suis infection. In the past, outbreaks have occurred in relatively small clusters. What makes this outbreak unusual (and has created skepticism about its purported cause) is its size and extent, the high associated mortality rate, the prominent presence of hemorrhages in the skin, and the fact that meningitis has not been reported by the media. If it is the case that S. suis is the cause of these illnesses, perhaps the organism has acquired one or more virulence factors from organisms such as group A streptococci or Staphylococcus aureus.

Aggressive Strain of HIV-1 Appears to Be Isolated Case

25 July (Reuters Health [Karla Harby])— Suggestions that a new, highly multidrugresistant and rapidly progressing strain of HIV-1 has evolved in New York City and could become widespread have been refuted by the discovery of the probable patient source of the virus, according to a presentation at the 3rd International AIDS Society Conference on HIV Pathogenesis and Treatment.

The rapid progression to AIDS observed in a patient discovered earlier this year led the New York City Department of Health to issue a press release on 11 February 2005, warning of a possible new, highly virulent, and multidrug resistant HIV strain. This was followed by reports in The Lancet and elsewhere.

The apparent source patient, “Patient Zero,” is a resident of Connecticut, and his clinical course is typical of AIDS patients with his disease, behavior, and medical compliance, said Dr. Gary Blick, medical and research director of Circle Medical LLC, Norwalk, Connecticut.

The patient's viral replication capacity (VRC) is 41%, and since he has become fully compliant with HAART, his CD4 findings—percentage 10%–13%; number 180–262—and viral copy number (!400) have remained stable.

“He is not a rapidly progressive patient,” Dr. Blick said. His life partner's disease course is similarly unremarkable.

By contrast, the New York City patient, whose disease so alarmed clinicians, has shown a VRC as high as 136%, Dr. Blick said. The patient was infected with a dualtropic virus ∼4 months before he progressed to AIDS. That patient has a history of extensive unprotected sex and multiple partners, often while using crystal methamphetamine.

The Patient Zero identified in Connecticut carries a virus that is a 99.5% pol gene match to that of the New York patient, Dr. Blick said. His life partner, who is also HIV positive, has a genetic match of 98.5%. In addition to the genetic evidence of virus transmission, the patients involved were able to identify each other visually and confirmed anal-receptive or anal-insertive intercourse, Dr. Blick said.

Dr. Blick hypothesized that the rapid course and treatment resistance experienced by the New York patient can be attributed to unusual host factors, including an unusually active sexual lifestyle and heavy use of crystal methamphetamine. It is also possible that this HIV-1 variant is not as responsive to treatment or that these 2 factors are interacting to produce this outcome, he said.

Attack on US Food Supply “Easy,” Senators Warn

21 July (Reuters Health [Sophie Walker])— An attack on America's food supply using biological agents is easy to do, would spread fast, and would have a devastating economic effect, a Senate committee heard as it reviewed protection for US agriculture.

“In the case of foot-and-mouth disease it takes little scientific training,” Senator Pat Roberts, a Kansas Republican and chairman of the Intelligence Committee, told the Agriculture Committee hearing.

“You put a handkerchief under a diseased animal in Afghanistan, put it in a zip-lock bag, put it in your suitcase, come to the United States, and drop it in any one of our feed lots. And we're in a lot of trouble.”

Other animal diseases such as Rift Valley fever in Africa, Nipah virus in Asia, and avian influenza are significant threats because of their contagious nature and the fact that they can cause death in humans, James Roth, director of the center for food security and public health at Iowa State University, testified before the hearing.

Deputy Agriculture Secretary Chuck Conner said that the US food system contributes $1.24 trillion, or 112%, to gross domestic product and employs 18% of the US work force.

Food products flow quickly via interstate commerce, making the sector particularly vulnerable. “Diseases and pathogens do not acknowledge state or national borders. The threat to agriculture is very real,” Conner said.

To help companies safeguard US food, the US Department of Agriculture has issued some voluntary guidelines. These include security guidelines for the livestock industry, meat processing plants, and truckers transporting agricultural commodities to prevent contamination, Conner said.

The Department of Homeland Security (DHS) is developing an agricultural forensics team to understand quickly who perpetrated an intentional event and provide information that can be used in court, said Maureen McCarthy, director of DHS's office of research and development.

John Lewis, deputy assistant director of the Federal Bureau of Investigation's Counterterrorism Division, said the bureau had set up an agriculture intelligence working group and was reaching out to farmers, cattle ranchers, food producers, and distributors.

“We know from the body of intelligence collected to date that al Qaeda is aware of our agriculture industry, along with other potential targets,” he said.

Clostridium sordellii Toxic Shock Syndrome After Medical Abortion with Mifepristone and Intravaginal Misoprostol—United States and Canada, 2001–2005

22 July—On 19 July 2005, the Food and Drug Administration (FDA) issued a public health advisory regarding the deaths of 4 women in the United States after medical abortions with Mifeprex (mifepristone, formerly RU-486; Danco Laboratories, New York, New York) and intravaginal misoprostol. Two of these deaths occurred in 2003, 1 in 2004, and 1 in 2005. Two of these US cases had clinical illness consistent with toxic shock and had evidence of endometrial infection with Clostridium sordellii, a gram-positive, toxin-forming anaerobic bacteria. In addition, a fatal case of C. sordellii toxic shock syndrome after medical abortion with mifepristone and misoprostol was reported in 2001, in Canada. All 3 cases of C. sordellii infection were notable for lack of fever, and all had refractory hypotension, multiple effusions, hemoconcentration, and a profound leukocytosis. C. sordellii previously has been described as a cause of pregnancy-associated toxic shock syndrome.

Investigation by FDA, Centers for Disease Control and Prevention (CDC), and state and local health departments into the 2 most recently identified US deaths after medical abortion is ongoing. Empiric therapy for patients suspected of having postpartum or postabortion toxic shock syndrome should include antimicrobials with anaerobic activity against Clostridium species. Health care providers are encouraged to report any cases of postpartum or postabortion toxic shock syndrome to their state or local health department and to CDC at telephone [phone]. Cases potentially associated with use of mifepristone or misoprostol should also be reported through the FDA MedWatch system available at http://www.fda.gov/medwatch/index.html or telephone 800- FDA-1088.

Source: MMWR Morb Mortal Wkly Rep 2005; 54:724.