News Scan for Nov 24, 2014

MERS strikes 2 more
;
More chikungunya cases
;
Flu-infection study
;
Multistate Salmonella sproutbreak

Two new MERS-CoV cases in Taif bring Saudi total to 810

A new case over the weekend and another today, both in the city of Taif, bring the total case count for MERS-CoV in Saudi Arabia to 810 since June 2012, according to updates from the country's Ministry of Health (MOH).

The first patient, whose case was reported Nov 22, is a 58-year-old Taif man in stable condition. He is not a healthcare worker but did have preexisting disease. No known contacts with MERS-CoV (Middle East respiratory syndrome coronavirus) in the community or healthcare setting were reported, and his exposure to animals, a potential risk factor, is listed as "under investigation."

The newest patient, an expatriate living in Taif, is a 42-year-old man in critical condition. He is not a healthcare worker and had no animal exposure or known contact with MERS patients in the community. He did have preexisting disease, and his exposure to MERS-CoV patients in the healthcare setting is given as "under investigation."

The MOH reported no new deaths or recoveries from the disease, so those totals stand at 346 and 451, respectively, leaving 13 active cases.

Taif, which is near Mecca, has reported numerous MERS-CoV cases this fall. Saudi Arabia saw a lull in disease activity over the summer before the recent pickup.
Nov 22 MOH update
Nov 24 MOH update

 

Caribbean chikungunya outbreak tops 900,000 cases

The Pan American Health Organization (PAHO) reported 36,553 more cases of chikungunya in the Caribbean and Americas, according to a Nov 21 update. The new cases bring the outbreak total to 933,102.

The total includes 914,960 suspected and 15,906 confirmed locally acquired cases, as well as 2,236 imported cases. Belize also reported its first 3 cases, all confirmed.

The death total, however, has decreased by 4 since the last PAHO outbreak report on Nov 14, bringing the number of outbreak-related deaths to 150. The decrease is likely due to reclassified illnesses that were initially suspected to be chikungunya.

El Salvador reported the largest increase with 29,955 new cases since the Nov 14 report, bringing its outbreak total to 123,229. Martinique also reported a sizeable increase of 10,005 cases, bringing its total to 79,860. The US reported 223 new imported chikungunya cases.

The Caribbean territories of French Guiana, St. Barthelemy, and St. Martin all reported decreases in suspected cases and steady numbers of confirmed cases since the last report, suggesting that several suspected chikungunya cases have been reclassified as other illnesses.
Nov 21 PAHO update

 

Flu-infection study notes early virus shedding, infrequent fevers

US researchers intentionally infected volunteers with influenza virus in concentrations intended to cause mild to moderate illness and found that they shed virus on average for 4 or 5 days, but only 10% had a fever, according to a new study in Clinical Infectious Diseases.

Researchers from the National Institute of Allergy and Infectious Diseases (NIAID) inoculated 46 adults with a 2009 H1N1 virus synthesized in the lab but genetically identical to the wild-type virus. Study subjects were divided into five groups that were exposed to increasing virus concentrations. The groups ranged in size from 4 to 19 people, the authors noted, and volunteers were paid $3,000 each, earlier media reports said.

In the group receiving the highest virus concentration—107 TCID50—9 of 13 volunteers (69%) shed virus and developed symptoms, which the researchers determined was the minimum dose required to produce mild to moderate flu. TCID50 (tissue culture infection dose-50) is the amount of virus required to produce cell death in 50% of inoculated cultured cells.

Groups receiving the next-highest virus concentrations—105 TCID50 and 106 TCID50—had symptom rates 80% or higher, but the proportion of those experiencing both symptoms and shedding did not meet the 60% cutoff. Rates for meeting both criteria in those two groups were 20% and 47%, respectively.

The researchers also noted that viral shedding preceded symptoms by about 12 to 24 hours and ended 2 to 3 days before symptoms did, indicating that individuals may be infectious before they develop symptoms, a phenomenon that has been reported before. One volunteer shed virus for 3 days without having symptoms. Viral shedding typically began 1 to 2 days after virus challenge and lasted as long as 9 days, with a mean of 4 to 5 days.

Fever was identified in 10% of participants, and those who did not have detectable virus shedding experienced less clinical illness, the team reported.

The authors concluded, "This unique clinical research program will facilitate future studies of influenza pathogenesis, animal model validation, and the rapid, efficient, and cost-effective evaluation of efficacy of novel vaccines and therapeutics."

The scientists first reported their results in September at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Denver.
Nov 20 Clin Infect Dis abstract
Sep 13 NIAID news release on ICAAC presentation

 

Multistate Salmonella outbreak traced to mung bean sprouts

Mung bean sprouts from a Brooklyn company are the source of a Salmonella Enteritidis outbreak that has sickened 63 people in 10 states, according to a Nov 21 report from the Centers for Disease Control and Prevention (CDC).

The investigation focused on Salmonella cases reported from Sep 30 to Nov 8. Cases occurred in Connecticut, Maine, Massachusetts, Montana, New Hampshire, New York, Ohio, Pennsylvania, Rhode Island, and Vermont.

The majority of people sickened had eaten at Asian-style restaurants, and 78% of people had eaten bean sprouts in the week before falling ill. Hospitalization was necessary in 26% of outbreak cases.

Five case clusters in Massachusetts, Rhode Island, and Vermont led investigators to strongly suspect bean sprouts as the outbreak source.

CDC identified Brooklyn-based Wonton Foods, Inc. as the source of the contaminated bean sprouts, and the company has since stopped all production and shipment of sprouts.
Nov 21 CDC report

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