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Zika virus is an arthropod-borne virus that is a member of the family Flaviviridae transmitted mainly by mosquitoes of the genus Aedes. Although usually asymptomatic, infection can result in a mild and self-limiting illness characterised by fever, rash, arthralgia, and conjunctivitis. An increase in the number of children born with microcephaly was noted in 2015 in regions of Brazil with high transmission of Zika virus. More recently, evidence has been accumulating supporting a link between Zika virus and microcephaly. Here, we describe findings from three fatal cases and two spontaneous abortions associated with Zika virus infection. In this case series, formalin-fixed paraffin-embedded tissue samples from five cases, including two newborn babies with microcephaly and severe arthrogryposis who died shortly after birth, one 2-month-old baby, and two placentas from spontaneous abortions, from Brazil were submitted to the Infectious Diseases Pathology Branch at the US Centers for Disease Control and Prevention (Atlanta, GA, USA) between December, 2015, and March, 2016. Specimens were assessed by histopathological examination, immunohistochemical assays using a mouse anti-Zika virus antibody, and RT-PCR assays targeting the NS5 and envelope genes. Amplicons of RT-PCR positive cases were sequenced for characterisation of strains. Viral antigens were localised to glial cells and neurons and associated with microcalcifications in all three fatal cases with microcephaly. Antigens were also seen in chorionic villi of one of the first trimester placentas. Tissues from all five cases were positive for Zika virus RNA by RT-PCR, and sequence analyses showed highest identities with Zika virus strains isolated from Brazil during 2015. These findings provide strong evidence of a link between Zika virus infection and different congenital central nervous system malformations, including microcephaly as well as arthrogryposis and spontaneous abortions. None.

Table 1 Date of caesarean Presentation Parity Breed of Dam Service Date 07/02/13 Breech (twins) 3 Holstein Friesian 07/05/12 09/02/13 Head back 5 Holstein Friesian 09/05/12 26/02/13 Head back 1 Jersey 19/05/12 27/02/13 Head back 4 Guernsey 23/05/12 02/03/13 Breech (twins) 4 Holstein Friesian 31/05/12 05/03/13 Breech 2 Holstein Friesian 28/05/12 07/03/13 All four legs 1 Holstein Friesian 31/05/12 10/03/13 Breech 1 Jersey 03/06/12

Objectives: To report on a case of fetal varicella infection following the diagnosis of maternal infection at 16 weeks of gestation. Methods: Diagnosis was based on serology testing and prenatal ultrasound, confirmed by DNA detection in amniotic fluid (Lightcycler-PCR). Serial ultrasound examinations were performed. Results: Sonographic anomalies included borderline ventriculomegaly, intracerebral, intrahepatic and myocardial calcifications, limb deformities, articular effusions, and intrauterine growth retardation (confirmed postpartally). The newborn showed a severe encephalopathy and could not be stabilized sufficiently. The child died 23 days after birth. Conclusion: The outcome of an affected fetus may be very serious and prenatal ultrasound is a helpful tool to recognize the severity of the infection.

Abstract Recently, piglets from a high-health status farm began exhibiting congenital tremors, high preweaning mortality and incidence of splayed legs. Postmortem histological examination identified a small number of scattered white matter vacuoles in the cerebellum and underlying brainstem of affected piglets. Presence of potential viral sources associated with this neurologic condition was initially infirmed using quantitative PCR for atypical porcine pestivirus (APPV), porcine teschovirus, and porcine sapelovirus. Using metagenomic analysis, APPV was identified as the main microbial species in serum obtained from piglets affected by congenital tremor. These piglets had higher preweaning mortality rates (46.4% vs. 15.3%) and incidence of splayed legs (33.0% vs. 0.8 %) compared to unaffected piglets. Piglets affected by congenital tremor had higher viral titer (P < 0.15) and larger birth weights (P < 0.05) compared to normal litter mates. Whole-genome sequencing and genome assembly of the novel APPV strain (MK728876) was carried out using Oxford Nanopore and related bioinformatics pipelines. Phylogenic analysis demonstrated that this strain along with other completely sequenced APPV strains were grouped into 2 clades, both including strains-inducing congenital tremor. Strains appear to cluster based on region but there were still significant differences within regions. Future research needs to address potential underdiagnosis due to genetic diversity but also to understand mode of transmission, variation in virulence, and the role of host genetics in APPV susceptibility.

Background Congenital tremor (CT) type A-II is a neurological disorder characterized by tremor of the head and body of newborn piglets. The suggested causative agent of the disease is the recently found atypical porcine pestivirus (APPV). The virus has been detected in piglets suffering from congenital tremor in central Europe, South and North America and in China but no studies has so far been performed in the Nordic countries. The overarching goal of this study was to investigate if APPV is present in the brain tissue of Swedish piglets suffering from congenital tremor. From June 2017 – June 2018, 15 piglets from four Swedish farms with ongoing outbreaks of congenital tremor and 13 piglets with splay leg originating from four different farms, were investigated for presence of APPV RNA in brain tissue. Matched healthy control piglets ( n  = 8) were also investigated. Two APPV-specific RT-qPCR methods targeting the NS3 and NS5B region, respectively, were used. A retrospective study was performed on material from Swedish piglets with congenital tremor sampled in 2004 ( n  = 11) and 2011/2012 ( n  = 3) using the described APPV-specific RT-qPCR methods. The total number of piglets with signs of CT in this study was 29. Results Atypical porcine pestivirus-RNA was detected in 93% (27/29) of the piglets suffering from congenital tremor. All piglets with congenital tremor from 2004 ( n  = 11) and 2012 ( n  = 3) were PCR-positive with respect to APPV, whereas, all of the healthy controls (n = 11) were negative. The piglets with congenital tremor sampled 2017–2018 had an odds ratio of 91.8 (95% CI 3.9128 to 2153.7842, z = 2.807, P  = 0.0050) to test positive for APPV by qRT-PCR compared to the healthy piglets (Fishers exact test p  < 0.0001). These findings make it interesting to continue investigating APPV in the Swedish pig-population. Conclusion This is the first description of atypical porcine pestivirus in piglets suffering from congenital tremor type A-II in Sweden and the Nordic countries. The virus has been present in the Swedish pig population since at least 2004.

Transgenic mice were generated with pRSV-CAT, a chimeric gene construct containing the long terminal repeat of Rous sarcoma virus (RSV) linked to the bacterial gene encoding chloramphenicol acetyltransferase (CAT). CAT expression, detected in adult animals of five independent strains, was preferentially directed to organs rich in tendon, bone, and muscle. This pattern reflects the disease specificity of the intact virus and suggests that the tissue tropism of RSV is determined at least in part by the presence of endogenous tissue-specific factors that can promote expression of genetic information linked to the long terminal repeat. In two of the mouse strains, insertion of the pRSV-CAT DNA resulted in developmental abnormalities. One of these strains was characterized by a dominant trait of embryonic lethality, the other by a recessive trait of fused toes in all four feet.