Presence of Recombinant Bat Coronavirus GCCDC1 in Cambodian Bats

Bats have been recognized as an exceptional viral reservoir, especially for coronaviruses. At least three bat zoonotic coronaviruses (SARS-CoV, MERS-CoV and SARS-CoV-2) have been shown to cause severe diseases in humans and it is expected more will emerge. One of the major features of CoVs is that they are all highly prone to recombination. An extreme example is the insertion of the P10 gene from reoviruses in the bat CoV GCCDC1, first discovered in Rousettus leschenaultii bats in China. Here, we report the detection of GCCDC1 in four different bat species (Eonycteris spelaea, Cynopterus sphinx, Rhinolophus shameli and Rousettus sp.) in Cambodia. This finding demonstrates a much broader geographic and bat species range for this virus and indicates common cross-species transmission. Interestingly, one of the bat samples showed a co-infection with an Alpha CoV most closely related to RsYN14, a virus recently discovered in the same genus (Rhinolophus) of bat in Yunnan, China, 2020. Taken together, our latest findings highlight the need to conduct active surveillance in bats to assess the risk of emerging CoVs, especially in Southeast Asia.

Systemic inflammation, innate immunity and pathogenesis after Zika virus infection in cynomolgus macaques are modulated by strain-specificity within the Asian lineage

Zika virus (ZIKV) is an emerging arbovirus with recent global expansion. Historically, ZIKV infections with Asian lineages have been associated with mild disease such as rash and fever. However, recent Asian sub-lineages have caused outbreaks in the South Pacific and Latin America with increased prevalence of neurological disorders in infants and adults. Asian sub-lineage differences may partially explain the range of disease severity observed. However, the effect of Asian sub-lineage differences on pathogenesis remains poorly characterized. Current study conducts a head-to-head comparison of three Asian sub-lineages that are representative of the circulating ancestral mild Asian strain (ZIKV-SG), the 2007 epidemic French Polynesian strain (ZIKV-FP), and the 2013 epidemic Brazil strain (ZIKV-Brazil) in adult Cynomolgus macaques. Animals infected intervenously or subcutaneously with either of the three clinical isolates showed sub-lineage-specific differences in viral pathogenesis, early innate immune responses and systemic inflammation. Despite the lack of neurological symptoms in infected animals, the epidemiologically neurotropic ZIKV sub-lineages (ZIKV-Brazil and/or ZIKV-FP) were associated with more sustained viral replication, higher systemic inflammation (i.e. higher levels of TNFα, MCP-1, IL15 and G-CSF) and greater percentage of CD14+ monocytes and dendritic cells in blood. Multidimensional analysis showed clustering of ZIKV-SG away from ZIKV-Brazil and ZIKV-FP, further confirming sub-lineage differences in the measured parameters. These findings highlight greater systemic inflammation and monocyte recruitment as possible risk factors of adult ZIKV disease observed during the 2007 FP and 2013 Brazil epidemics. Future studies should explore the use of anti-inflammatory therapeutics as early treatment to prevent ZIKV-associated disease in adults.

Dengue virus activates cGAS through the release of mitochondrial DNA

Cyclic GMP-AMP synthetase (cGAS) is a DNA-specific cytosolic sensor, which detects and initiates host defense responses against microbial DNA. It is thus curious that a recent study identified cGAS as playing important roles in inhibiting positive-sense single-stranded RNA (+ssRNA) viral infection, especially since RNA is not known to activate cGAS. Using a dengue virus serotype 2 (DENV-2) vaccine strain (PDK53), we show that infection creates an endogenous source of cytosolic DNA in infected cells through the release of mitochondrial DNA (mtDNA) to drive the production of cGAMP by cGAS. Innate immune responses triggered by cGAMP contribute to limiting the spread of DENV to adjacent uninfected cells through contact dependent gap junctions. Our result thus supports the notion that RNA virus indirectly activates a DNA-specific innate immune signaling pathway and highlights the breadth of the cGAS-induced antiviral response.

Dengue virus neutralization in cells expressing Fc gamma receptors

Activating Fc gamma receptors (FcγRs) in hematopoietic cells serve to remove antibody-opsonized antigens, including dengue virus (DENV), from systemic circulation. While neutralizing antibody concentrations provide humoral immunity, cross-reactive or sub-neutralizing levels of antibody can result in antibody-dependent enhancement of DENV infection that increases overall viral burden. Recently, it has been suggested that the antibody levels needed for DENV neutralization differs when different FcγR is engaged. If this is true, the threshold titer used to infer immunity should be influenced by FcγR usage. Here, using cells that express both activating and inhibitory FcγRs, we show that the type of FcγR engaged during phagocytosis can influence the antibody concentration requirement for DENV neutralization. We demonstrate that phagocytosis through FcγRI requires significantly less antibody for complete DENV neutralization compared to FcγRIIA. Furthermore, when DENV is opsonized with sub-neutralizing levels of antibody, FcγRI-mediated phagocytosis resulted in significantly reduced DENV titers compared to FcγRIIA. However, while FcγRI may remove antibody-opsonized DENV more efficiently, this receptor is only preferentially engaged by clustering when neutralizing, but not sub-neutralizing antibody concentrations, were used. Collectively, our study demonstrates that activating FcγR usage may influence antibody titers needed for DENV neutralization.

The prevalence of antibodies to adenovirus serotype 5 in an adult Indian population and implications for adenovirus vector vaccines

In vivo gene delivery using human adenovirus serotype 5 (AdV5) vectors is being explored for vaccination purposes. The presence of anti-AdV5 antibodies in human serum arising from natural exposure to AdV5 can interfere potentially with and compromise the efficacy of rAdV5-based vaccine vectors. In this report, a collection of 114 sera from healthy adult Indian blood donors was analyzed for the presence of anti-AdV5 antibodies, using an AdV5 vector encoding the green fluorescent protein (GFP) to monitor the presence of anti-AdV5 neutralizing antibodies in human sera based on their ability to block virus entry into HeLa cells which express the Coxsackievirus-and-Adenovirus Receptor (CAR). In this assay all samples tested were positive for anti-AdV5 antibodies, with titers varying over a very wide range. It was also observed that these antibodies facilitated the uptake of the reporter AdV5 vector into the monocytic cell line U937 which does not express CAR, but expresses Fc receptors (FcRs) instead. These observations have implications for rAdV5-based vaccine development. J. Med. Virol. 82:407-414, 2010. (c) 2010 Wiley-Liss, Inc.

Recurrent acute pancreatitis due to a santorinicele in a young patient

A cystic dilatation of the terminal portion of the minor pancreatic duct (duct of Santorini) is referred to as a santorinicele. It is usually associated with pancreas divisum and has been suggested to be a cause of relative stenosis of the minor papilla, often leading to recurrent pancreatitis. While this anomaly has been reported in the paediatric population, it is more commonly found in the elderly. We present a 27-year-old woman with recurrent acute pancreatitis attributed to a santorinicele with a dorsal duct-exclusive pancreatic drainage.

Gastric variceal bleed in a patient without liver cirrhosis: an unusual cause of haematemesis

Tumours of the pancreas presenting as haematemesis are rare entities, with scarce documentation in literature. We report a 50-year-old woman who presented with haematemesis secondary to gastric fundal variceal bleeding due to splenic vein occlusion by a large mucinous cystadenoma of the pancreas. We also review the literature pertaining to unusual pathologies presenting as haematemesis.

An audit of blood cross-match ordering practices at the Aga Khan University Hospital: first step towards a Maximum Surgical Blood Ordering Schedule

OBJECTIVE

In the absence of an explicit maximum blood order policy, ordering for blood transfusion is frequently based on subjective anticipation of blood loss instead of evidence based estimates of average requirement in a particular procedure. This study was done to assess current practice and the feasibility of a prospective randomized work to develop practice guidelines.

METHOD

We audited transfusion data for elective surgical procedures in our hospital during the last 2 years. Cross-matched to transfused ratio (C/T ratio) and Transfusion Index (Ti) for each of the elective surgical procedures was performed during the study period. C/T ratio is used as a measure of the efficiency of blood ordering practice. It should ideally be between 2 and 2.5. We compared our results with the ideal.

RESULTS

Data was analyzed for 32 elective surgical procedures in 2131 patients. Majority (2079) (97.56%) of the patients had C/T ratios higher than 2.5. Only 12 in 450 (21.11%) patients, had a Transfusion Index (Ti) higher than 0.5. There were 13 procedures in which both C/T ratio was greater than 2.5 and Ti less than or equal to 0.5.

CONCLUSION

In vast majority of elective surgical procedures routine cross match is not necessary. We propose a draft Maximum Surgical Blood Ordering Schedule (MSBOS). It provides guidelines for frequently performed elective surgical procedures by recommending the maximum number of units of blood to be cross-matched preoperatively. Implementation of MSBOS will result in about 60% reduction of cost to the patients.

Multiple immunizations. Ouch!

The purpose of this study was to determine the stated willingness of parents/caretakers to allow the administration of multiple, injected immunizations to their children at a single visit. Two hundred eighty-one parents/caretakers accompanying their children to an inner-city pediatric clinic were presented with hypothetical situations in which their children would be due for two, three, or four injections to complete their series of age-appropriate immunizations. Given a scenario of two needed injections, 24 (8.5%) of the 281 parents/caretakers preferred to divide the injections between two visits; for three injections, 119 (42.3%) preferred two visits; and for four injections, 164 (58.4%) preferred two visits. The commonly stated preference of our predominantly minority parent/caretaker population to divide more than two injections between two visits seriously conflicts with the US Public Health Service's National Vaccine Advisory Committee's recommendations and potentially exacerbates immunization delays. Therefore, physicians must be prepared to strongly urge simultaneous administration of all needed vaccine doses at any opportunity.