How well are we collecting umbilical cord lactate and gas samples?

AIMS: The aim of this study is to measure staff compliance with the local umbilical cord lactate (UCL) sampling guideline and investigate the quality of paired UCG samples at a tertiary maternity unit. METHODS: We performed a retrospective consecutive sampling of 100 babies delivered via emergency caesarean section and 50 babies with each of all other guideline-based indications for UCL sampling born on and before 31 December 2021. Data were extracted from physical and electronic records. Compliance with guideline-based indications for UCL at birth was measured. The proportion of valid UCG samples was calculated. Samples were considered invalid under the following cases: (i) inadvertently collecting from the same vessel, (ii) switching arterial and venous samples, (iii) collecting from only one vessel or (iv) committing errors during sample collection and handling. RESULTS: Of the samples collected at birth from 321 babies, 280 (87%) had UCL. Small for gestational age and concerns about fetal well-being in labour were indications associated with poorer compliance, 66% and 78%, respectively. About 99 (44%) babies of 226 babies with UCG performed had valid UCG samples. The most common reasons for invalid samples were collection and handling errors (22%) and inadvertent collection from the same vessel (15%). CONCLUSIONS: Generally, compliance with the guidelines is good. However, invalid UCG samples were more frequent than expected.

Molecular epidemiology of Japanese encephalitis in northern Vietnam, 1964-2011: genotype replacement.

BACKGROUND: Japanese encephalitis virus (JEV) is an arthropod-borne virus causing serious public health issues in Asia. JEV consists of five genotypes and recent studies have shown the emergence of JEV genotype I (GI) and its replacement of genotype III (GIII). Using an archival JEV collection, we investigated the molecular evolution of JEV in Vietnam over the last 48 years (1964-2012) in humans, mosquitoes, and pigs, within the global context. METHODS: The nine JEV isolates from humans, pigs, and mosquitoes sequenced in this study and 29 sequences available in GenBank were used to analyze the envelope (E) protein of the Vietnamese JEVs. A collection of 225 cerebrospinal fluid specimens from patients with suspected Japanese encephalitis (JE) was also tested and genotyped with real-time RT-PCR. RESULTS: The 38 E genes identified with sequencing and nine Vietnamese JEV strains genotyped with real-time RT-PCR, belonging to two lineages, evolved in accordance with those in the rest of the world. The first GIII strain was detected in humans in Vietnam in 1964, and in mosquitoes in 1979, whereas GI strains were first detected in humans and mosquitoes in 1990 and 1994, respectively. After 2004, GI was the only genotype detected in Vietnam, demonstrating that the GIIII strains had been displaced by GI strains. Five haplotypes were identified in the Vietnamese JEVs, with SKSS predominant. The S123N and S123R substitutions in the E protein were already present in the Vietnamese JEVs. CONCLUSION: This study describes the long evolutionary history of JEV in Vietnam over 34 years, which correlates well with the global evolution of JEV. The Vietnamese GIII strains have been replaced by GI strains in mosquitoes, pigs, and humans. The predominant haplotypes of the Vietnamese strains support this genotype displacement in Vietnam. Further surveillance is required to confirm the disappearance of the GIII strains in nature and the emergence of new pathogens causing encephalitis in Vietnam, after the long-term use of JEV vaccines in that country.

Mechanism of Japanese encephalitis virus genotypes replacement based on human, porcine and mosquito-originated cell lines model.

OBJECTIVE: To examine the multiplication efficiency Japanese encephalitis virus (JEV) genotype I (GI) and genotype III (GIII) of different cell lines which originated from human, porcine, mosquitoes in order to prove mechanism of JEV GI replacement JEV GIII since it emerging in nature recent decades. METHODS: The mixture of GI and GIII JEV isolates was inoculated on human rhabdomyosarcoma (RD), pig kidney epithelial (PS) and Aedes albopictus C6/36 clone (C6/36) which originated from human, porcine and mosquitoes, respectively. Plaque assays were performed to calculate virus titer and real-time RT-PCR with GI and GIII specific primer sets to quantify the number of GI and GIII RNA copies. RESULTS: The highest virus titer reached at the 3rd day of post infection when GI and GIII mixture was inoculated on RD and PS and that of C6/36 was at the 4th day. JEVs were amplified and maintained by C6/36 cells after 10 passages whereas that by RD and PS only limited within 8 and 6 passages, respectively. GI strain amplified and maintained more efficiently on C6/36 and PS but not RD, whereas GIII strain amplified and maintained more efficiently on RD. CONCLUSIONS: There is a correlation between the multiplication efficiency of GI and GIII JEV strains when these two genotype strains co-infected on different cell lines with the predominance of GI strains in C6/36 and PS and the limited detection of GI strains in RD cells proving a possible mechanism of shift JEV genotypes in nature recent decades since GI emerging.