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Background Alaska Native (AN) infants are at risk for severe disease due to respiratory syncytial virus (RSV) and influenza. Maternal immunization protects young infants through transplacental antibody transfer. RSV- and influenza-specific transplacental antibody transfer in mother–infant pairs has not previously been evaluated in the AN population. Methods Serum samples collected during pregnancy and at birth from AN mother–infant pairs in the Yukon-Kuskokwim Delta region (YKD) of Alaska (2000–2011; n = 75) and predominantly white pairs in Seattle, Washington (2014–2016; n = 57), were tested for RSV and influenza antibody using a microneutralization and hemagglutination inhibition assay, respectively, and compared between sites. Results Mean RSV antibody concentrations in pregnant women in YKD and Seattle were similar (log2 RSV antibody 10.6 vs 10.7, P = .86), but cord blood RSV antibody concentrations were significantly lower in infants born to mothers in YKD compared with Seattle (log2 RSV antibody 11.0 vs 12.2, P < .001). Maternal and cord blood influenza antibody concentrations were lower for women and infants in YKD compared with Seattle for all 4 influenza antigens tested (all P < .05). The mean cord to maternal RSV antibody transfer ratio was 1.15 (standard deviation [SD], 0.13) in mother–infant pairs in Seattle compared with 1.04 (SD, 0.08) in YKD. Mean cord blood to maternal antibody transfer ratios for influenza antigens ranged from 1.22 to 1.42 in Seattle and from 1.05 to 1.59 in YKD. Conclusions Though the transplacental antibody transfer ratio was high (>1.0) for both groups, transfer ratios for RSV antibody were significantly lower in AN mother–infant pairs. Further studies are needed to elucidate the impact of lower transplacental antibody transfer on infant disease risk in rural Alaska. Alaska Native and continental US mother-infant pairs have high transplacental antibody transfer ratios (>1.0) for influenza and respiratory syncytial virus, but anti-respiratory syncytial virus antibody levels are significantly lower in Alaska Native pairs than in those from the continental US.

Before introduction of Haemophilus influenzae type b (Hib) vaccines, rates of Hib disease in Alaska's indigenous people were among the highest in the world. Vaccination reduced rates dramatically; however, invasive H. influenzae type a (Hia) disease has emerged. Cases of invasive disease were identified through Alaska statewide surveillance during 1983-2011. Of 866 isolates analyzed for serotype, 32 (4%) were Hia. No Hia disease was identified before 2002; 32 cases occurred during 2002-2011 (p

This paper describes the molecular detection of respiratory viruses from nasopharyngeal flocked swabs (flocked swabs) and nasopharyngeal washes (washes) in a clinical setting. Washes and flocked swabs collected from children3 years old hospitalized with a lower respiratory tract infection were tested for parainfluenza virus 1-3, respiratory syncytial virus, influenza A and B and metapneumovirus (Group 1) and adenovirus, rhinovirus and coronavirus (Group 2) using real-time reverse transcriptase PCR (rRT-PCR). A consensuses standard was used to determine sensitivity and compare cycle thresholds (C(T)) of washes and flocked swabs for each virus and group of viruses. Sensitivities ranged from 79 to 89% and 69 to 94% for flocked swabs and washes, respectively, excluding AdV which had a sensitivity of 35% for flocked swabs. When the flocked swabs and washes of Group 1 viruses were collected on the day of admission, the sensitivity of both sample types was 100%. Wash specimens had a lower C(T) value and higher sensitivity than flocked swabs; however there was no statistical difference in the sensitivity of a flocked swab (89%) versus wash (93%) for the detection of Group 1 viruses, particularly when samples were collected on the same day. Flocked swabs may be a useful alternative to washes for detection of respiratory viruses in clinical settings.

Infants from Alaska's Yukon-Kuskokwim Delta (YKD) have a high respiratory syncytial virus (RSV) hospitalization rate (104/1000/yr). Appropriate patient management requires rapid and accurate RSV diagnosis. Antigen-based methods are often used in clinical settings, but these tests can lack sensitivity.We compared Binax NOW(®) RSV (BN) used for RSV diagnosis in the YKD hospital with a real-time polymerase chain reaction assay (RT-qPCR) used for viral surveillance.Between October 2005 and September 2007 we obtained nasopharyngeal washes (NPW) from children3 years hospitalized with a lower respiratory tract infection. The NPW were tested using BN and RT-qPCR.79/311 (25%) children had RSV infection as determined by RT-qPCR. As compared with RT-qPCR, sensitivity and specificity of BN were 72% and 97%, respectively. The sensitivity of BN was higher in children1 year compared with children ≥ 1 year (79% vs. 52%; p=0.025), children with bronchiolitis compared with children without bronchiolitis (89% vs. 38%; p0.001), and children with a shorter duration of symptoms before testing (0-1 (92%) vs. 2-4 (78%) vs. 5+ (65%) days; p=0.04). The median RSV viral load in NPW positive by BN and RT-qPCR was 1.01 × 10(9)copies/mL vs. a median of 5.25 × 10(7)copies/mL for NPW positive by RT-qPCR only (p0.001).RT-qPCR is more sensitive than BN in detecting RSV infection. BN sensitivity is high in children with bronchiolitis, but the sensitivity is low when children present with a non-bronchiolitis illness, especially after a longer duration of symptoms before testing.

Serotype a is now the most common seen in the North American Arctic; highest rates occur in indigenous children., Before the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines, rates of invasive H. influenzae disease among indigenous people of the North American Arctic were among the highest in the world. Routine vaccination reduced rates to low levels; however, serotype replacement with non–type b strains may result in a reemergence of invasive disease in children. We reviewed population-based data on invasive H. influenzae in Alaska and northern Canada from 2000–2005; 138 cases were reported. Among 88 typeable isolates, 42 (48%) were H. influenzae type a (Hia); 35 (83%) occurred in indigenous peoples. Among Hia patients, median age was 1.1 years; 62% were male; 1 adult died. Common clinical manifestations included meningitis, pneumonia, and septic arthritis. Overall annual incidence was 0.9 cases per 100,000 population. Incidence among indigenous children

OBJECTIVE. Before 1991, Alaska Native children experienced one of the highest rates of invasive Haemophilus influenzae type b disease. H influenzae type b vaccine has led to a near-elimination of invasive H influenzae type b disease in the United States. We describe challenges encountered in controlling H influenzae type b disease in Alaska and update the current status of H influenzae disease and carriage in Alaska as lessons to other populations.PATIENTS AND METHODS. We reviewed data from statewide H influenzae disease surveillance conducted during 1980–2004. Vaccine coverage data were based on audits from tribal facilities and the National Immunization Survey. H influenzae type b colonization data were based on 6 carriage studies.RESULTS. After universal infant vaccination in 1991, H influenzae type b disease among Alaska Native and non-Native children CONCLUSIONS. H influenzae type b vaccination has resulted in a dramatic decrease in invasive H influenzae type b disease in Alaska; however, despite high rates of H influenzae type b vaccine coverage, H influenzae type b disease rates among rural Alaska Native children

OBJECTIVE: Lower respiratory tract infections (LRTIs) are a major cause of morbidity for children worldwide and particularly for children from developing and indigenous populations. In this study, we evaluated risk factors for hospitalization with LRTI in a region in southwest Alaska. METHODS: The study was conducted from October 1, 2006, to September 30, 2007, in the Yukon Kuskokwim Delta region of Alaska. Cases were recruited from children RESULTS: One hundred twenty-eight cases were matched to 186 controls. In a multivariable conditional logistic regression model, significantly (P < .05) increased risk of hospitalization was associated with medically high-risk status, having a woodstove in the house, being bottle fed, and vomiting after feeding; living in a house that had 2 or more rooms with sinks was a protective factor. Viral loads in hospitalized cases were significantly higher than those in controls, but a strict cutoff level was not observed. CONCLUSIONS: Several risk factors for LRTI hospitalization were identified in this high risk population. Some factors are amenable to environmental and behavioral interventions.

We evaluated nasopharyngeal carriage of Streptococcus pneumoniae (pneumococci) in nine Alaskan communities and used an algorithm combining microbiologic, serologic, and sequential multiplex PCR (MP-PCR) techniques to serotype the isolates. After microbiological identification as pneumococci, isolates ( n = 1,135) were serotyped using latex agglutination and Quellung tests (LA/Q) as well as a series of six sequential MP-PCR assays. Results from the two methods agreed for 94% (1,064/1,135) of samples. Eighty-six percent (61/71) of the discordant results were resolved. Discordant results occurred because (i) the MP-PCR gel was misread (31/61 [51%]), (ii) the LA/Q agglutination was misinterpreted (13/61 [21%]), (iii) two serotypes or sets of serotypes were identified by MP-PCR and only one of the two was identified by LA/Q (9/61 [15%]), (iv) different serotypes or sets of serotypes were identified by LA/Q and MP-PCR and both were correct (7/61 [11%]), and (v) the capsular polysaccharide locus ( cps ) did not amplify during the initial MP-PCR but was present upon retesting (1/61 [2%]). Overall, isolation of pneumococci followed by MP-PCR quickly and accurately identified pneumococcal serotypes in >97% of samples and made available isolates for additional tests such as antimicrobial susceptibility. Misinterpretation of the MP-PCR gel was identified as the main source of discordance. Increasing the number of MP-PCRs from six to seven and reducing the number of serotypes in each reaction may reduce this error. This method may be of use to laboratories characterizing large numbers of S. pneumoniae samples, especially when antimicrobial susceptibility data are needed.

Respiratory syncytial virus (RSV) in Alaska Native children from the Yukon Kuskokwim (YK) Delta is associated with a hospitalization rate five times higher than that reported for the general US child population. The role of other viral respiratory pathogens has not been studied in this population. YK Delta children