2013-08-18 20:04:06 中新网
疾控中心主任弗里登博士(Dr. Thomas Frieden)表示，他们已向国会提出4000万美元的资金支持，以更新其硬件和软件，从而实时分析像环孢子虫这样的微生物基因组序列。
From CDC website: Progression of the Outbreak Investigation
Current Updates expanded. August 28, 2013
As of August 27, 2013 (5pm EDT), a total of 616 ill persons with Cyclospora infection have been reported from 22 states. Since the last update on August 26, 6 additional ill people were reported.
Ill persons range in age from less than one year to 92 years, with a median age of 51 years. Fifty-six percent (56%) of ill persons are female. Among 591 ill persons for whom information is available, 45 (8%) have reported being hospitalized. No deaths have been reported.
Illnesses that occurred after July 22, 2013, might not yet have been reported because of the time it takes between when a person becomes ill and when the illness is reported. This could take up to 5 to 6 weeks.
Cyclospora cayetanensis is a single-celled parasite that causes an intestinal infection called cyclosporiasis.
As of August 27, 2013 (5pm EDT), CDC has been notified of 616 ill persons with Cyclospora infection from 22 states: Arkansas, California, Connecticut, Florida, Georgia, Illinois, Iowa, Kansas, Louisiana, Minnesota, Missouri, Nebraska, New Jersey, New Hampshire, New York (including New York City), Ohio, South Dakota, Tennessee, Texas, Virginia, Wisconsin, and Wyoming. Most of the illness onset dates have ranged from mid-June through mid-July.
Among 591 ill persons with available information, 45 (8%) have reported being hospitalized. No deaths have been reported.
Public health officials in Iowa and Nebraska performed investigations within their states and concluded that restaurant-associated cases of Cyclospora infection in their states were linked to a salad mix produced by Taylor Farms de Mexico. On August 12, 2013, Taylor Farms de Mexico informed FDAExternal Web Site Icon that the company had voluntarily suspended production and shipment of any salad mix, leafy green, or salad mix components from its operations in Mexico to the United States.
On August 25, 2013, Taylor Farms de Mexico, with FDA concurrenceExternal Web Site Icon, resumed production and shipment of salad mix, leafy greens, and salad mix components to the United States.
Currently, CDC is collaborating with the Texas Department of Health and Human Services and local public health departments to investigate cases of cyclosporiasis reported among people in Texas. The preliminary analysis of results from an investigation into a cluster of cases that ate at a Texas restaurant does not show a connection to Taylor Farms de Mexico. This investigation is ongoing.
Although the investigation of cases continues, available evidence suggests that not all of the cases of cyclosporiasis in the various states are directly related to each other.
Consumers should continue to enjoy the health benefits of eating fresh fruits and vegetables as part of a well-balanced diet. Consumers and retailers should always follow safe produce handling recommendations.
CDC will update the public as more information becomes available, including steps consumers can take to protect themselves.
The causal agent has been only recently identified as a single-celled coccidian parasite. The species designation Cyclospora cayetanensis was given in 1994 to Peruvian isolates of human-associated Cyclospora. It appears that all human cases are caused by this species.
Life cycle of Cyclospora cayetanensis
Some of elements of this figure were created based on an illustration by Ortega et al. Cyclospora cayetanensis. In: Advances in Parasitology: opportunistic protozoa in humans. San Diego: Academic Press; 1998. p. 399-418.
When freshly passed in stools, the oocyst is not infective The number 1 (thus, direct fecal-oral transmission cannot occur; this differentiates Cyclospora from another important coccidian parasite, Cryptosporidium). In the environment The number 2, sporulation occurs after days or weeks at temperatures between 22°C to 32°C, resulting in division of the sporont into two sporocysts, each containing two elongate sporozoites The number 3. Fresh produce and water can serve as vehicles for transmission The number 4 and the sporulated oocysts are ingested (in contaminated food or water) The number 5. The oocysts excyst in the gastrointestinal tract, freeing the sporozoites which invade the epithelial cells of the small intestine The number 6. Inside the cells they undergo asexual multiplication and sexual development to mature into oocysts, which will be shed in stools The number 7. The potential mechanisms of contamination of food and water are still under investigation.