Search

Bronchopulmonary dysplasia (BPD) is a disease prevalent in preterm babies with a need for supplemental oxygen, resulting in impaired lung development and dysregulated vascularization. Epidemiologic studies have shown that males are more prone to BPD and have a delayed recovery compared with females, for reasons unknown. Herein, we tried to recapitulate mild, moderate, and severe BPD, using two different strains of mice, in males and females: CD1 (outbred) and C57BL/6 (inbred). Aside from higher body weight in the CD1 strain, there were no other gross morphologic differences with respect to alveolar development between the two strains. With respect to lung morphology after oxygen exposure, females had less injury with better preservation of alveolar chord length and decreased alveolar protein leak and inflammatory cells in the bronchoalveolar lavage fluid. In addition, housekeeping genes, which are routinely used as loading controls, were expressed differently in males and females. In the BPD mouse model, gonadotropin-releasing hormone was increased in females compared with males. Specific miRNAs (miR-146 and miR-34a) were expressed differently in the sexes. In the severe BPD mouse model, administering miR-146 mimic to males attenuated lung damage, whereas administering miR-146 inhibitor to females increased pulmonary injury.

Background Currently, the primary mechanism for poliovirus detection is acute flaccid paralysis (AFP) surveillance, with environmental sampling serving as a complement. However, as AFP cases drop, environmental surveillance will become increasingly critical for poliovirus detection. Mexico provides a natural environment to study oral polio vaccine (OPV) transmission, as it provides routine injected polio vaccine immunization and biannual OPV campaigns in February and May. Methods As part of a study of OPV transmission in which 155 children were vaccinated with OPV, monthly sewage samples were collected from rivers leading from 3 indigenous Mexican villages (Capoluca, Campo Grande, and Tuxpanguillo) from February to May 2015. Samples were also collected from October 2015 to October 2017, during which time there were standard OPV campaigns. Samples were analyzed for the presence of OPV serotypes, using a real-time qualitative polymerase chain reaction assay capable of detecting as few as 9, 12, and 10 copies/100 µL of viral ribonucleic acid for OPV serotypes 1, 2, and 3 (OPV-1, -2, and -3), respectively. Included here are 54 samples, taken up to November 2016. Results Of the 54 samples, 13 (24%) were positive for OPV. After the vaccination of 155 children in February 2015, OPV was found 2 months after vaccination. After unrestricted OPV administration in February 2016, OPV was detected in sewage up to 8 months after vaccination. OPV-3 was found in 11 of the 13 positive samples (85%), OPV-2 was found in 3 positive samples (23%), and OPV-1 was found in 1 sample (8%). Conclusions OPV can be detected even when small amounts of the vaccine are introduced into a community, as shown by OPV-positive sewage samples even when only 155 children were vaccinated. When OPV vaccination was unrestricted, sewage samples were positive up to 8 months after vaccination, implying community OPV circulation for at least 8 months. OPV-3 was the serotype most found in these samples, indicating prolonged transmission of OPV-3 when compared to the other serotypes. Future work could compare the phylogenetic variance of OPV isolates from sewage after OPV vaccinations.

Background Global polio eradication efforts rely in part on molecular methods of detecting polioviruses, both wild and vaccine strains, from human and environmental samples. Previous assays used for detection of Sabin oral polio vaccine (OPV) in fecal samples have been labor and time intensive and vary in their sensitivity and specificity. Methods We developed a high-throughput, multiplex reverse-transcription quantitative polymerase chain reaction assay able to detect all 3 OPV strains in fecal samples. The assay used a KingFisher Duo Prime system for viral RNA isolation and extraction. Positive samples were retested and Sanger sequenced for verification of Sabin serotype identity. Results The 95% lower limit of detection was determined to be 3 copies per reaction for Sabin 1 and 3 and 4 copies per reaction for Sabin 2, with no cross-reactivity between the 3 serotypes and their primers. A total of 554 samples (3.6%) were positive, with 304 positive samples (54.9%) containing >1 serotype. Of the positive samples, 476 (85.9%) contained enough RNA to be sequenced, and of these all sequences were Sabin serotypes. The previous assay we used could process 48 samples in a 10-hour period, whereas the new assay processed >100 samples in 6 hours. Conclusions The new high-throughput, multiplex reverse-transcription quantitative polymerase chain reaction assay allowed for sensitive and specific detection of OPV serotypes while greatly decreasing sample handling and processing time. We were able to sequence 72.4% of the 210 positive samples in the cycle threshold range of 35–37.

Background The World Health Assembly 2012 Polio Eradication and Endgame Strategic Plan calls for the eventual cessation of all oral polio vaccines (OPVs), to be replaced with inactivated polio vaccine (IPV); however, IPV induces less robust mucosal immunity than OPV. This study characterized household and community OPV shedding and transmission after OPV vaccination within primarily IPV-vaccinated communities. Methods Households in 3 IPV-vaccinated Mexican communities were randomized to receive 3 levels of OPV vaccination coverage (70%, 30%, or 10%). Ten stool samples were collected from all household members over 71 days. Analysis compared vaccinated subjects, household contacts of vaccinated subjects, and subjects in unvaccinated households. Logistic and Cox regression models were fitted to characterize transmission of OPV by coverage and household vaccination status. Results Among 148 vaccinated children, 380 household contacts, and 1124 unvaccinated community contacts, 78%, 18%, and 7%, respectively, shed OPV. Community and household contacts showed no differences in transmission (odds ratio [OR], 0.67; 95% confidence interval [CI], .37–1.20), in shedding trajectory (OR, 0.61; 95% CI, .35–1.07), or in time to shedding (hazard ratio, 0.68; 95% CI, .39–1.19). Transmission began as quickly as 1 day after vaccination and persisted as long as 71 days after vaccination. Transmission within unvaccinated households differed significantly across vaccination coverage communities, with the 70% community experiencing the most transmissions (15%), and the 10% community experiencing the least (4%). These trends persisted over time and in the time to first shedding analyses. Conclusions Transmission did not differ between household contacts of vaccinees and unvaccinated households. Understanding poliovirus transmission dynamics is important for postcertification control.

Bronchopulmonary dysplasia (BPD) is a multifactorial disease of preterm infants characterized by alveolar simplification, dysregulated pulmonary vasculature, and pulmonary hypertension. Invasive mechanical ventilation, hyperoxia, infection, and various other contributing factors acting on the immature lung result in permanent damage to the pulmonary architecture. Animal models have played a critical role in our understanding of the pathogenesis behind this very complex disease, and this chapter will attempt to describe the uses, advantages, and limitations of the mouse, rat, guinea pig, rabbit, lamb, baboon, and rhesus monkey models of BPD.

Background As wild poliovirus is nearing global eradication and countries switch from Oral Polio Vaccine (OPV) to Inactivated Polio Vaccine (IPV), preventing circulating vaccine-derived poliovirus is a top priority. However, the circulation of OPV serotypes remains a concern in undervaccinated communities. We sought to examine the relationship between pediatric nutritional status and OPV shedding based on length-for-age categorizations. Mexico provides a natural environment to study these patterns as it provides routine IPV immunization and bi-annual OPV campaigns. Methods We enrolled 466 households with children eligible for OPV before the February 2015 national health week from 3 semi-rural Indigenous communities near Orizaba, Mexico. In each community, a different proportion of eligible children received OPV (10%, 30%, 70%), with a total of 155 vaccinated children. OPV shedding was measured by RT-qPCR detection of OPV in samples collected serially over 10 weeks. Anthropometric measurements were collected and compared with the WHO Multicenter Growth Reference Study growth curves to assign stunting. Associations between stunting, OPV shedding, and shedding duration were tested by Fisher exact test and Wilcoxon-Man-Whitney Test (α = 0.05). Results Samples of fecal OPV isolates were collected over time and analyzed from 148 vaccinees. 25 (17%) of the vaccinees were stunted. There was no relationship between pediatric stunting and likelihood of ever shedding any serotype of OPV (P = 0.82). The mean duration of OPV shedding by stunted and non-stunted children differed, but not significantly (10.9 days vs. 9.3 days, respectively, P = 0.32). We did not find any statistically significant differences between stunting status and shedding of any individual OPV serotype. Conclusion Further understanding of factors related to OPV shedding is necessary to approach efficient worldwide poliovirus control. We found no relationship between stunting status and both OPV shedding and shedding duration post-vaccination, suggesting that nutritional status does not play a role in OPV shedding. The ongoing analysis includes longitudinal analysis of OPV shedding patterns by nutritional status, and the impact of stunting on viral load and reversion of OPV to vaccine-associated paralytic polio mutants. Disclosures All authors: No reported disclosures.