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MMWR News Synopsis for December 4, 2014

No MMWR telebriefing scheduled for
December 4, 2014

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Full MMWR articles


Chikungunya Cases Identified through Passive Surveillance and Household Investigations — Puerto Rico, May 5–August 12, 2014

CDC Media Relations

Chikungunya was first detected in Puerto Rico in May 2014. To avoid chikungunya, travelers to and residents of regions of the Americas where mosquitoes that transmit the disease are present should use standard measures to avoid mosquito bites. Chikungunya is a viral disease that causes fever and severe joint pain. In late 2013, chikungunya was introduced into the western hemisphere, where nearly 1 million cases have since been reported. In Puerto Rico, between early May and mid-August more than 10,000 chikungunya cases were reported, including four fatal cases. House-to-house investigations suggest that the actual magnitude of the epidemic is larger than reflected by the number of reported cases. Because there is no preexisting immunity against chikungunya in the Americas and sustainable and effective approaches to mosquito control are not available, chikungunya is expected to continue to spread throughout the regions of the Americas where the mosquitoes that transmit the disease are present.

Pertussis Epidemic — California, 2014

California Department of Public Health Office of Public Affairs

Pertussis incidence is likely to continue to increase in the United States due to the natural cycle of disease and the waning of immunity conferred by currently available vaccines. Strategies to prevent the most severe cases of pertussis, which occur primarily in young infants, should be prioritized. California is experiencing a pertussis epidemic. During January 1–November 26, a total of 9,935 cases of pertussis with onset in 2014 were reported in California, for an incidence of 26.0 cases per 100,000 population. The highest burden of disease is being observed in infants aged <12 months, especially Hispanic infants, and in white, non-Hispanic teenagers aged 14–16 years. This is consistent with the upper age of the cohort of children who have only received acellular pertussis vaccine. Severe and fatal disease occurs almost exclusively in infants who are too young to be vaccinated against pertussis. Therefore, pregnant women are encouraged to receive tetanus, diphtheria, and acellular pertussis vaccine (Tdap) during the third trimester of each pregnancy to provide placental transfer of maternal antibodies to the infant. Prenatal care providers are encouraged to provide Tdap to pregnant women or refer patients to obtain vaccine from an alternative provider, such as a pharmacy or local public health department.

Respiratory Syncytial Virus — United States, July 2012–June 2014

CDC Media Relations

RSV seasonal patterns in 2012-2013 and 2013-2014 remained consistent with previous years and demonstrated the usual differences in RSV circulation among HHS regions. Respiratory syncytial virus (RSV) is a leading cause of lower respiratory infection in infants and young children worldwide. In the United States, RSV predominantly circulates in the fall, winter and spring. A network of U.S. laboratories report RSV specimen results to the National Respiratory and Enteric Virus Surveillance System, which summarizes geo-temporal trends in RSV circulation. The 2012-2013 season onset occurred nationally in late-October and ended in late March. Circulation peaked in early January. During the 2013-2014 season onset occurred nationally in early November and ended in late March. Circulation peaked in late-December. RSV circulation in both seasons varied among the regions. RSV seasonality guides diagnostic testing and timing of RSV immunoprophylaxis for populations at high risk for severe respiratory infection.

Notes from the Field: 

Transmission of Chikungunya Virus in the Continental United States — Florida, 2014