First report of Serotype-1 Marek’s disease virus (MDV-1) with oncogenic form in backyard turkeys in Turkey: a molecular analysis study

Background Marek’s disease (MD) is a lymphoproliferative disease caused by Gallid alphaherpesvirus 2 (GaHV-2, MDV-1), which primarily affects chickens. However, the virus is also able to induce tumors and polyneuritis in turkeys, albeit less frequently than in chickens. Results This is the first study in Turkey reporting the molecular characterization of a MDV-1 strain detected in a flock of backyard turkeys exhibiting visceral lymphoma. Here, MEQ, vIL-8, pp38 and 132-bp tandem repeat regions, which are frequently preferred in the pathotyping of MDV-1, were examined. It was determined that the MEQ gene of MDV-1/TR-21/turkey strain obtained in the present study encoded 339 amino acids (1020 nt) and had four proline-rich repeat regions (PPPP). Based on the nucleotide sequence of the MEQ gene of the MDV-1/TR-21/turkey strain, a phylogenetic tree was created using the MEGA-X software with the Maximum Likelihood Method (in 1000 replicates). Our strain was highly identical (> 99.8) to the Italian/Ck/625/16, Polish (Polen5) and some Turkish (Layer-GaHV-2-02-TR-2017, Tr/MDV-1/19) MDV-1 strains. Also, nt and aa sequences of the MEQ gene of our strain were 99.1 and 99.41% identical to another Turkish strain (MDV/Tur/2019) originated from chickens. Sequence analysis of pp38 and vIL-8 genes also supported the above finding. The identity ratios of nucleotide and amino acid sequences of vIL-8 and pp38 genes of MDV-1/TR-21/turkey strain were 99.64–100% and 99.79–100%, respectively, when compared with those of the Polish strain. According to 132-bp tandem repeat PCR results, the MDV-1/TR-21/turkey strain had five copies. Conclusions These results suggested that the MDV-1/TR-21/turkey strain obtained from backyard turkeys can be either very virulent or very virulent plus pathotype, though experimental inoculation is required for precise pathotyping.

Extracellular Vesicles from Different Pneumococcal Serotypes Are Internalized by Macrophages and Induce Host Immune Responses

Bacterial extracellular vesicles are membranous ultrastructures released from the cell surface. They play important roles in the interaction between the host and the bacteria. In this work, we show how extracellular vesicles produced by four different serotypes of the important human pathogen, Streptococcus pneumoniae, are internalized by murine J774A.1 macrophages via fusion with the membrane of the host cells. We also evaluated the capacity of pneumococcal extracellular vesicles to elicit an immune response by macrophages. Macrophages treated with the vesicles underwent a serotype-dependent transient loss of viability, which was further reverted. The vesicles induced the production of proinflammatory cytokines, which was higher for serotype 1 and serotype 8-derived vesicles. These results demonstrate the biological activity of extracellular vesicles of clinically important pneumococcal serotypes.

Six decades of infectious bursal disease in poultry: The journey so far and challenges ahead

Despite six decades of concerted efforts, Infectious bursal disease (IBD) still remains a major threat to the poultry industry worldwide. Most importantly, the emergence of variant and very virulent strains of infectious bursal disease virus (IBDV) has dramatically changed the epidemiology of the disease, thus resulting in the renewed efforts in the search for effective control measures. Currently, live attenuated, inactivated, and immune-complex vaccines are among the immune-therapeutic approaches employed for the control of IBD in the field alongside adequate biosecurity, albeit with various degrees of success and limitations. Progress in genetic engineering has allowed the generation of reverse genetic IBDV mutants, recombinant live viral vectors expressing the IBDV VP2 immunodominant protein, intra-serotypic recombinant IBDV viral-like particle co-expressing the outer capsid protein structures derived from 2 or more serotype 1 strains or the incorporation of either VP2 or VP2-4-3 polyprotein sequences alongside molecular adjuvants that can be used as IBD vaccine candidates to elicit an immune response. However, despite these advances, outbreaks are still reported even in flocks that have up to date vaccination records and somewhat excellent management practices. This paper reviews aspect of genetic characteristics of IBDV and reflects on the progress and future challenges in providing effective IBD vaccine to achieve effective control of both classical and very-virulent IBDV serotypes that constitute a major devastation to poultry production and health.

Genomic Diversity of Listeria monocytogenes Isolates From Slovakia (2010 to 2020)

Over the past 11 years, the Slovak National Reference Laboratory has collected a panel of 988 Listeria monocytogenes isolates in Slovakia, which were isolated from various food sectors (61%), food-processing environments (13.7%), animals with listeriosis symptoms (21.2%), and human cases (4.1%). We serotyped these isolates by agglutination method, which revealed the highest prevalence (61.1%) of serotype 1/2a and the lowest (4.7%) of serotype 1/2c, although these represented the majority of isolates from the meat sector. The distribution of CCs analyzed on 176 isolates demonstrated that CC11-ST451 (15.3%) was the most prevalent CC, particularly in food (14.8%) and animal isolates (17.5%). CC11-ST451, followed by CC7, CC14, and CC37, were the most prevalent CCs in the milk sector, and CC9 and CC8 in the meat sector. CC11-ST451 is probably widely distributed in Slovakia, mainly in the milk and dairy product sectors, posing a possible threat to public health. Potential persistence indication of CC9 was observed in one meat facility between 2014 and 2018, highlighting its general meat-related distribution and potential for persistence worldwide.

1176. Experience with PCV10 Implementation in Colombia and More Severe Course of Pneumococcal Pneumonia in children: A Multicenter Study, 2008 – 2019 (Neumocolombia Network)

Background Pneumococcal conjugate vaccines (PCV) have decreased pneumonia in children. Colombia introduced massive vaccination with PCV10 in 2012. Methods Pneumococcal pneumonia cases from 10 hospitals part of an active surveillance network for invasive pneumococcal disease were included. Two periods were compared, pre-PCV10: 2008-2012 and post-PCV10: 2014-2019. The objective was to compare characteristics and outcomes before and after PCV10. Results 370 cases were included. Serotype 1(15, 11.2%) and 14 (33, 24.6%) were the most frequent in Pre-PCV10, with only 4(3%) 19A and 1(0.7%) serotype 3. Post-PCV10, serotype 1 decreased to 6(3.1%), 14 to 15(7.8%), while 19A increased to 58(30.2%), serotype 3 to 32(16.7%) and 6A to 7(3.6%) (p = < 0.001), (Graph 1). Complicated pneumonia (CN) also increased (13.4% to 31,8%) (p< 0,001). Pre-PVC10, 44% of CN were due to PCV10 serotypes; with no PCV13 serotypes cases. Post-vaccine period, PCV10 explained only 8.2% and PCV13 60.6%(p < 0.001) of CN. Comparing PICU requirement among predominant serotypes on each period; 23.5% of serotypes 14 and 27.2% of serotypes 1 were admitted, while 59.4% of serotypes 3, 56.9 % of 19A and 42.8% of 6A required PICU. The median of hospitalization increased from 8(5.5-15) to 12 (7-22) days (p < 0.001), as well as the frequency of PICU, 32.8% to 51.6 %, (p = 0.001). Penicillin prescription was similar (17.2% -15.7%), with decrease in ampicillin use (28.4% - 3.6%) and increase ampicillin-sulbactam (0.7% to 24%), and ceftriaxone / clindamycin (0.7% to 5.7%) in post-PCV10. The duration of empirical antibiotic treatment was 7(4-11) and increased to 10(6-17) (p = < 0.001). Lethality showed a slight, non-significant increase between periods 7.5% vs. 9.9% (p = 0.57). (Table1) Graph 1. Serotype distribution 2008 - 2019 Year 2012, PCV10 introduced 2 + 1 schedule. Table 1. Outcomes in the Pre-PCV10 and Post-PCV10 Period Conclusion PCV10 significantly decreased vaccine serotypes, with increase in PCV13 serotypes. 19A, 3 and 6A the predominant serotypes had greater severity including PICU admission, CN and more resistance, with an increase in the use of broad-spectrum antibiotics and longer hospitalization. The current data support national and regional evidence on the importance of replacing PCV10 to a higher valence that include 19A, as PCV13, with the aim of reducing the circulation, particularly of this serotype. Disclosures Ivan Felipe Gutiérrez Tobar, n/a, Pfizer and MSD (Advisor or Review Panel member, Research Grant or Support, Speaker’s Bureau, Has received support from Pfizer and MSD for participation in congresses and has received conference payments from Pfizer)Pfizer and MSD (Speaker’s Bureau, Other Financial or Material Support, Has received support from Pfizer for participation in congresses) Cristina Mariño Drews, n/a, Pfizer (Other Financial or Material Support, Has received support from Pfizer for participation in congresses) Sandra Beltran, n/a, Pfizer (Other Financial or Material Support, Has received support from Pfizer for participation in congresses) Aura Lucia Leal Castro, MD, Pfizer and MSD (Research Grant or Support, Speaker’s Bureau, Other Financial or Material Support, Has received support from Pfizer for participation in congresses) Aura Lucia Leal Castro, n/a, Pfizer and MSD (Research Grant or Support, Speaker’s Bureau, Other Financial or Material Support, Has received support from Pfizer for participation in congresses) Jaime alberto Patiño-Niño, n/a, Pfizer (Research Grant or Support, Speaker’s Bureau, Other Financial or Material Support, Has received support from Pfizer for participation in congresses) Martha Isabel Alvarez-Olmos, n/a, Pfizer (Other Financial or Material Support, Has received support from Pfizer for participation in congresses) Rocio Barrero Barreto, n/a, Pfizer and MSD (Other Financial or Material Support, Has received support from Pfizer and MSD for participation in congresses and has received conference payments from Pfizer) Fabio Espinosa, n/a, MSD (Research Grant or Support, Other Financial or Material Support, Has received support from MSD for other research.) Nicolas Ramos, n/a, Pfizer (Other Financial or Material Support, Has received support from Pfizer for participation in congresses) Vivian Marcela Moreno Mejia, n/a, Pfizer (Research Grant or Support)

Using Background Sequencing Data to Anticipate DENV-1 Circulation in the Lao PDR

Since its first detection in 1979, dengue fever has been considered a major public health issue in the Lao People’s Democratic Republic (PDR). Dengue virus (DENV) serotype 1 was the cause of an epidemic in 2010–2011. Between 2012 and 2020, major outbreaks due successively to DENV-3, DENV-4 and recently DENV-2 have been recorded. However, DENV-1 still co-circulated in the country over this period. Here, we summarize epidemiological and molecular data of DENV-1 between 2016 and 2020 in the Lao PDR. Our data highlight the continuous circulation of DENV-1 in the country at levels ranging from 16% to 22% among serotyping tests. In addition, the phylogenetic analysis has revealed the circulation of DENV-1 genotype I at least since 2008 with a co-circulation of different clusters. Sequence data support independent DENV-1 introductions in the Lao PDR correlated with an active circulation of this serotype at the regional level in Southeast Asia. The maintenance of DENV-1 circulation over the last ten years supports a low level of immunity against this serotype within the Lao population. Thereby, the risk of a DENV-1 epidemic cannot be ruled out in the future, and this emphasizes the importance of maintaining an integrated surveillance approach to prevent major outbreaks.