Systemic Complications of COVID-19.

Coronavirus disease-2019 (COVID-19) creates severe respiratory distress and often a cascade of other systemic complications impacting several organ systems. The immune response includes a cytokine storm that creates many life-threatening problems including coagulopathies, arrhythmias, and secondary infections. This article discusses the multisystem responses to the physical insults created by this corona virus.

Deletion of v-chiA from a baculovirus reduces horizontal transmission in the field.

Nucleopolyhedroviruses (NPVs) can initiate devastating disease outbreaks in populations of defoliating Lepidoptera, a fact that has been exploited for the purposes of biological control of some pest insects. A key part of the horizontal transmission process of NPVs is the degradation of the larval integument by virus-coded proteins called chitinases, such as V-CHIA produced by the v-chiA genes. We used recombinant and naturally occurring strains of the Lymantria dispar NPV (LdMNPV) to test horizontal transmission in the field, release of virus from dead larvae under laboratory conditions, and cell lysis and virus release in cell culture. In the field, strains of LdMNPV lacking functional v-chiA genes showed reduced horizontal transmission compared to wild-type or repaired strains. These findings were mirrored by a marked reduction in released virus in laboratory tests and cell culture when the same strains were used to infect larvae or cells. Thus, this study tests the pivotal role of liquefaction and the v-chiA gene in field transmission for the first time and uses complementary laboratory data to provide a likely explanation for our findings.

Detection of infectious myonecrosis virus in penaeid shrimps using immunoassays: usefulness of monoclonal antibodies directed to the viral major capsid protein.

Despite the economic impact of the infectious myonecrosis virus (IMNV) on shrimp farms in several countries, no method for immunological detection is currently available. With the aim of developing immunodiagnostic methods for IMNV detection in infected shrimps, a recombinant fragment of the IMNV major capsid protein gene encoding amino acids 105-297 (rIMNV105₋297 was heterologously expressed in Escherichia coli and used to immunize Balb/c mice, generating monoclonal antibodies (MAbs). Six hybridomas were obtained, and four of these recognized the presence of IMNV in tissue homogenates from naturally infected shrimps by immunodot blot assay. Among these MAbs, three were able to detect a ~100-kDa protein, which corresponds to the predicted mass of the IMNV major capsid protein, as well as viral inclusion bodies in muscle fibroses by western blot and immunohistochemistry. Two MAbs showed high specificity and sensitivity, showing no cross-reaction with healthy shrimp tissues in any assays, indicating their usefulness for IMNV detection.

Transcriptome sequencing to unravel the molecular mechanisms underlying the cuticle liquefaction of Antheraea pernyi following Antheraea pernyi nucleopolyhedrovirus challenge.

Baculovirus causes liquefaction of insect cuticle to enhance the dissemination of progeny virions away from the host cadavers for increasing viral transmission rates. Antheraea pernyi nucleopolyhedrovirus (ApNPV) infects A. pernyi larvae with circular pus blotches formed in cuticle in the early stage of liquefaction. To investigate the formation mechanism of those pus blotches, the transcriptome profile changes of the cuticles between ApNPV-infected and non-infected A. pernyi larvae were analyzed using RNA-Seq. The transcriptome was de novo assembled using the Trinity platform. Comparison of gene expression levels revealed that a total of 2990 and 4427 unigenes were up- and down-regulated respectively in ApNPV-infected cuticle, of which 2620 and 1903 differentially expressed genes (DEGs) could be enriched in different GO terms and KEGG pathways. In this study, we focused on chitin metabolism related DEGs, and screened 10 genes involved in chitin synthesis and degradation with down-regulated trends, indicating that the chitin metabolism pathway was inhibited by ApNPV infection, which may promote liquefaction of A. pernyi cuticle. Besides, we also identified a large number of DEGs involved in immune related pathways via KEGG analysis, indicating that intense immune responses occurred in A. pernyi cuticle. Our research findings will serve as a basis for further researching the molecular mechanisms underlying cuticle liquefaction of A. pernyi induced by ApNPV infection.

Molt stage and cuticle damage influence white spot syndrome virus immersion infection in penaeid shrimp.

Transmission of white spot syndrome virus (WSSV) in shrimp has been reported to occur by feeding and immersion. In the present study, the impact of the molt process and artificial lesions in the cuticle on shrimp susceptibility to WSSV was examined using intramuscular and immersion routes. For the intramuscular route, Penaeus (Litopenaeus) vannamei shrimp (n=450) were injected with 10(-2.3) up to 10(2.7) shrimp infectious dose 50% end point (SID(50)) of WSSV in early and late post-molt, inter-molt, early and late pre-molt; resp. A-, B-, C-, D1- and D2-stage. The resulting infection titers demonstrated that no difference (p>0.05) in susceptibility existed between different molt stages when virus was injected. For the waterborne route, shrimp in different molt stages were immersed in seawater containing 10(4)SID(50)ml(-1) of WSSV. In a first study, P. vannamei (n=125) incubated in cell culture flasks, became infected with WSSV mostly in post-molt stages. In a second study, 2 groups of P. vannamei (n=100) and P. monodon (n=100) were transferred into plastic bags to prevent damage to the cuticle; and in 1 group a pleopod was cut off prior to incubation. Induction of damage increased infection significantly (p<0.05) in A-stage from 0-40% to 60-100%, in B-stage from 0-20% to 40-60%, in C-stage from 0-20 to 20-60%, while infection was 0% in D-stages with both immersion methods. This study proved that shrimp are more susceptible to WSSV infection via immersion after molting than in the period before molting and wounding facilitates infection.