NEWS SCAN: New ricin letter probe, US BSE risk, mutated mosquitoes, recurrent fungal meningitis, Zika case in Canada

Ricin letter threats target NYC mayor, gun control group
Two letters that threatened New York City mayor Michael Bloomberg tested positive to the deadly poison ricin in preliminary testing, the New York Times reported yesterday. Police said one of the letters was opened on May 24 at a mail center in Lower Manhattan and the other was opened on May 26 after it was delivered to the Washington, DC, office of Mayors Against Illegal Guns, a group Bloomberg directs and funds, according to the Times. Staff members at the mail facility in New York weren't sickened, but several police officers who came in contact with the letter have had some mild symptoms, including diarrhea, and are being evaluated as inpatients. No injuries have been reported in connection with the Washington letter. Both letters had a Louisiana postmark. Police spokesman Paul Browne told the Times that samples tested positive for ricin at the National Bioforensic Analysis Center in Maryland yesterday and that earlier local tests also suggested ricin. This is the third incident involving ricin letters this year. In April a Mississippi man was arrested for sending ricin to the president, a US senator, and a local judge, and earlier this month a man was charged for sending a ricin-laced letter to a district judge in Spokane, Wash.
May 29 New York Times story

OIE puts US in lowest risk category for BSE
The World Organization for Animal Health (OIE) has moved the United States to its lowest risk category for the spread of bovine spongiform encephalopathy (BSE, or mad cow disease), the US Department of Agriculture (USDA) announced yesterday. The US risk status was changed from "controlled" to "negligible." In welcoming the change, USDA Secretary Tom Vilsack called it "a significant achievement that has been many years in the making" for the US beef industry and federal and state governments. "This demonstrates OIE's belief that both our surveillance for, and safeguards against, BSE are strong," he added. Beef industry officials said the move should allay concerns that some countries still have about BSE risks associated with buying US beef products, according to a story today from Meatingplace. The story said the United States submitted an application last year to the OIE's Scientific Commission for the change in risk classification, and the commission recommended the upgrade in February after conducting a review. The change was formally adopted at the OIE's annual General Assembly this week in Paris, according to Meatingplace. Four BSE cases have been reported in US cattle. The most recent one, in April 2012, was described as an atypical case, a rare type that is not associated with consumption of contaminated feed.
May 29 statement by Vilsack
May 30 Meatingplace story
Apr 24, 2012, CIDRAP News story about latest US BSE case

Lab-mutated mosquitoes may lose ability to detect human odors
Mutating an odor co-receptor gene in mosquitoes eliminates their ability to detect human scents and the repellent DEET, according to a study today in Nature. US researchers targeted the orco gene, which some insects use to detect scents, in Aedes aegypti mosquitoes. "We knew this gene was important for flies to be able to respond to the odors they respond to," said Leslie Vosshall, PhD, of the Howard Hughes Medical Institute (HHMI) at The Rockefeller University, in an HHMI news release. "And we had some hints that mosquitoes interact with smells in their environment, so it was a good bet that something would interact with orco in mosquitoes." The hunch proved correct. In the presence of carbon dioxide, which helps mosquitoes detect human scent, the mutated mosquitoes showed no preference between human and guinea pig hosts. They also landed in equal numbers on a human arm slathered in 10% DEET and one not protected. But they soon flew off the DEET-saturated arm. "This tells us that there are two totally different mechanisms that mosquitoes are using to sense DEET," Vosshall said in the release, one olfactory based and one based on physical contact. A aegypti mosquitoes can transmit malaria and dengue.
May 29 Nature study on gene mutation
May 29 HHMI news release
In related news, mosquito transmission of the malaria parasite Plasmodium seems to control the severity of the resulting infection, a separate study in Nature today indicated. The findings suggest that the parasite's environment within the mosquito somehow lessens the virulence of Plasmodium. The UK researchers, who used a mouse model, said this finding may help in developing an antimalarial vaccine.
May 29 Nature study on Plasmodium virulence

Report warns of fungal meningitis relapse
Doctors from Virginia and officials at the US Centers for Disease Control and Prevention (CDC) yesterday in the New England Journal of Medicine reported a recent recurrence of fungal meningitis in a patient who was first sickened in October after receiving a contaminated corticosteroid spinal injection. The 80-year-old man is one of the 741 people who were sickened in the fungal illness outbreak linked to a Massachusetts compounding pharmacy. Three lots of the company's methylprednisolone acetate injections were traced to the illnesses, which spanned 20 states and led to the deaths of 55 people. The man was on voriconazole therapy for 4 1/2 months for his initial infection, which exceeded the current CDC recommendation of 3 months of treatment for fungal meningitis. In March, however, he redeveloped fungal meningitis symptoms, and lab tests showed evidence of infection. His physicians restarted voriconzaole treatment, and the man was discharged from the hospital 4 days later. The medical team wrote that the case serves as a warning that relapsed infections can occur. They said that close follow-up, including serial lumbar punctures after completing therapy, may be helpful for early detection of repeat infections.
May 29 N Engl J Med letter

Canada reports first imported Zika virus infection
Health officials in Alberta yesterday reported the first lab-confirmed Zika virus infection in Canada, an imported case involving a woman from the province who traveled to Thailand in late January. They described the clinical details and the lab workup in a post yesterday on ProMED Mail, the online reporting system of the International Society for Infectious Diseases. The 45-year-old woman sustained several mosquito bites while staying with her family at locations in Bangkok and Phuket Island and started feeling sick during a flight back to Canada on Feb 5. Three days later her symptoms got worse and she noted mouth blisters. She sought medical care when she started having a severe backache and rash on her extremities. Reverse-transcriptase polymerase chain reaction testing of sera for flavivirus was positive, and sequencing revealed Zika virus. Further testing of convalescent serum by the CDC confirmed the findings. The woman recovered after about 3 weeks.
May 29 ProMED post

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