Kay M. Tomashek

Dengue viremia in blood donors identified by RNA and detection of dengue transfusion transmission during the 2007 dengue outbreak in Puerto Rico

BACKGROUND: In 2007, a total of 10,508 suspected dengue cases were reported in Puerto Rico. Blood donations were tested for dengue virus (DENV) RNA and recipients of RNA‐positive donations traced to assess transfusion transmission.

US infant mortality trends attributable to accidental suffocation and strangulation in bed from 1984 through 2004: are rates increasing?

OBJECTIVE. Accidental suffocation and strangulation in bed, a subgroup of sudden, unexpected infant deaths, is a leading mechanism of injury-related infant deaths. We explored trends and characteristics of these potentially preventable deaths. METHODS. In this descriptive study, we analyzed US infant mortality data from 1984 through 2004. To explore trends in accidental suffocation and strangulation in bed and other sudden, unexpected infant deaths, we calculated cause-specific infant mortality rates and estimated proportionate mortality. Sudden, unexpected infant death was defined as a combination of all deaths attributed to accidental suffocation and strangulation in bed, sudden infant death syndrome, and unknown causes. Finally, we examined factors that were reported as contributing to these accidental suffocation and strangulation in bed deaths. RESULTS. Between 1984 and 2004, infant mortality rates attributed to accidental suffocation and strangulation in bed increased from 2.8 to 12.5 deaths per 100000 live births. These rates remained relatively stagnant between 1984 and 1992 and increased between 1992 and 2004; the most dramatic increase occurred between 1996 and 2004 (14% average annual increase). In contrast, total sudden, unexpected infant death rates remained stagnant between 1996 and 2004, whereas the proportion of deaths attributed to sudden infant death syndrome declined and to unknown cause increased. Black male infants <4 months of age were disproportionately affected by accidental suffocation and strangulation in bed. Beds, cribs, and couches were reported as places where deaths attributed to accidental suffocation and strangulation in bed occurred. CONCLUSIONS. Infant mortality rates attributable to accidental suffocation and strangulation in bed have quadrupled since 1984. The reason for this increase is unknown. Prevention efforts should target those at highest risk and focus on helping parents and caregivers provide safer sleep environments.

Dengue virus in blood donations, Puerto Rico, 2005

BACKGROUND: A single instance of transfusion‐transmitted dengue infection has been reported. The high incidence of dengue in endemic countries, the high proportion of asymptomatic infection, and the median 5‐day viremia, however, suggest that transfusion‐associated dengue transmission may be more widespread than documented.

Dengue outbreak in Key West, Florida, USA, 2009.

After 3 dengue cases were acquired in Key West, Florida, we conducted a serosurvey to determine the scope of the outbreak. Thirteen residents showed recent infection (infection rate 5%; 90% CI 2%–8%), demonstrating the reemergence of dengue in Florida. Increased awareness of dengue among health care providers is needed.

Outbreak of Carbapenem-Resistant Klebsiella pneumoniae in Puerto Rico Associated with a Novel Carbapenemase Variant

BACKGROUND Carbapenem-resistant Klebsiella pneumoniae (CRKP) is resistant to almost all antimicrobial agents, and CRKP infections are associated with substantial morbidity and mortality. OBJECTIVE To describe an outbreak of CRKP in Puerto Rico, determine risk factors for CRKP acquisition, and detail the successful measures taken to control the outbreak. DESIGN Two case-control studies. SETTING A 328-bed tertiary care teaching hospital. PATIENTS Twenty-six CRKP case patients identified during the outbreak period of February through September 2008, 26 randomly selected uninfected control patients, and 26 randomly selected control patients with carbapenem-susceptible K. pneumoniae (CSKP) hospitalized during the same period. METHODS We performed active case finding, including retrospective review of the hospitals microbiology database and prospective perirectal surveillance culture sampling in high-risk units. Case patients were compared with each control group while controlling for time at risk. We sequenced the bla(KPC) gene with polymerase chain reaction for 7 outbreak isolates and subtyped these isolates with pulsed-field gel electrophoresis. RESULTS In matched, multivariable analysis, the presence of wounds (hazard ratio, 19.0 [95% confidence interval {CI}, 2.5-142.0]) was associated with CRKP compared with no K. pneumoniae. Transfer between units (adjusted odds ratio [OR], 7.5 [95% CI, 1.8-31.1]), surgery (adjusted OR, 4.0 [95% CI, 1.0-15.7]), and wounds (adjusted OR, 4.9 [95% CI, 1.1-21.8]) were independent risk factors for CRKP compared to CSKP. A novel K. pneumoniae carbapenemase variant (KPC-8) was present in 5 isolates. Implementation of active surveillance for CRKP colonization and cohorting of CRKP patients rapidly controlled the outbreak. CONCLUSIONS Enhanced surveillance for CRKP colonization and intensified infection control measures that include limiting the physical distribution of patients can reduce CRKP transmission during an outbreak.

Virus-Specific Differences in Rates of Disease during the 2010 Dengue Epidemic in Puerto Rico

Background Dengue is a potentially fatal acute febrile illness (AFI) caused by four mosquito-transmitted dengue viruses (DENV-1–4) that are endemic in Puerto Rico. In January 2010, the number of suspected dengue cases reported to the passive dengue surveillance system exceeded the epidemic threshold and an epidemic was declared soon after. Methodology/Principal Findings To characterize the epidemic, surveillance and laboratory diagnostic data were compiled. A suspected case was a dengue-like AFI in a person reported by a health care provider with or without a specimen submitted for diagnostic testing. Laboratory-positive cases had: (i) DENV nucleic acid detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in an acute serum specimen; (ii) anti-DENV IgM antibody detected by ELISA in any serum specimen; or (iii) DENV antigen or nucleic acid detected in an autopsy-tissue specimen. In 2010, a total of 26,766 suspected dengue cases (7.2 per 1,000 residents) were identified, of which 46.6% were laboratory-positive. Of 7,426 RT-PCR-positive specimens, DENV-1 (69.0%) and DENV-4 (23.6%) were detected more frequently than DENV-2 (7.3%) and DENV-3 (<0.1%). Nearly half (47.1%) of all laboratory-positive cases were adults, 49.7% had dengue with warning signs, 11.1% had severe dengue, and 40 died. Approximately 21% of cases were primary DENV infections, and 1–4 year olds were the only age group for which primary infection was more common than secondary. Individuals infected with DENV-1 were 4.2 (95% confidence interval [CI]: 1.7–9.8) and 4.0 (95% CI: 2.4–6.5) times more likely to have primary infection than those infected with DENV-2 or -4, respectively. Conclusions/Significance This epidemic was long in duration and yielded the highest incidence of reported dengue cases and deaths since surveillance began in Puerto Rico in the late 1960s. This epidemic re-emphasizes the need for more effective primary prevention interventions to reduce the morbidity and mortality of dengue.

Travel-associated dengue infections in the United States, 1996 to 2005.

BACKGROUND As the incidence of dengue increases globally, US travelers to endemic areas may be at an increased risk of travel-associated dengue. METHODS Data from the US Centers for Disease Control and Preventions laboratory-based Passive Dengue Surveillance System (PDSS) were used to describe trends in travel-associated dengue reported from January 1, 1996 to December 31, 2005. The PDSS relies on provider-initiated requests for diagnostic testing of serum samples via state health departments. A case of travel-associated dengue was defined as a laboratory-positive dengue infection in a resident of the 50 US states and the District of Columbia who had been in a dengue-endemic area within 14 days before symptom onset. Dengue infection was confirmed by serologic and virologic techniques. RESULTS One thousand one hundred and ninety-six suspected travel-associated dengue cases were reported-334 (28%) were laboratory-positive, 597 (50%) were laboratory-negative, and 265 (22%) were laboratory-indeterminate. The incidence of laboratory-positive cases varied from 1996 to 2005, but had an overall increase with no significant trend (53.5 to 121.3 per 10(8) US travelers, p = 0.36). The most commonly visited regions were the Caribbean, Mexico and Central America, and Asia. The median age of laboratory-positive cases was 37 years (range: <1 to 75 y) and 166 (50%) were male. Of the 334 laboratory-positive cases, 41 (12%) were hospitalized, and 2 (1%) died. CONCLUSIONS Residents of the US traveling to dengue-endemic regions are at risk of dengue infection and need to be instructed on appropriate prevention measures prior to travel. Especially in light of the potential transmissibility of dengue virus via blood transfusion, consistent reporting of travel-associated dengue infections is essential.

Clinical and Laboratory Features That Differentiate Dengue from Other Febrile Illnesses in an Endemic Area—Puerto Rico, 2007–2008

Dengue infection can be challenging to diagnose early in the course of infection before severe manifestations develop, but early diagnosis can improve patient outcomes and promote timely public health interventions. We developed age-based predictive models generated from 2 years of data from an enhanced dengue surveillance system in Puerto Rico. These models were internally validated and were able to differentiate dengue infection from other acute febrile illnesses with moderate accuracy. The accuracy of the models was greater than either the current World Health Organization case definition for dengue fever or a proposed modification to this definition, while requiring the collection of fewer data. In young children, thrombocytopenia and the absence of cough were associated with dengue infection; for adults, rash, leucopenia, and the absence of sore throat were associated with dengue infection; in all age groups, retro-orbital pain was associated with dengue infection.

Validity of Maternal and Perinatal Risk Factors Reported on Fetal Death Certificates

We sought to estimate the accuracy, relative to maternal medical records, of perinatal risk factors recorded on fetal death certificates. We conducted a validation study of fetal death certificates among women who experienced fetal deaths between 1996 and 2001. The number of previous births, established diabetes, chronic hypertension, maternal fever, performance of autopsy, anencephaly, and Down syndrome had very high accuracy, while placental cord conditions and other chromosomal abnormalities were reported inaccurately. Additional population-based studies are needed to identify strategies to improve fetal death certificate data.

COMMENTARY: Nutritional Rickets in Georgia

Opinions expressed in commentaries are those of the authors and not necessarily those of the American Academy of Pediatrics or its Committees. Commentaries are not peer-reviewed.