Parvovirus infection: an immunohistochemical study using fetal and placental tissue

Enterovirus Placentitis is an Underrecognized Cause of Placental Pathology

The placenta is susceptible to infection by a number of viral pathogens, including severe acute respiratory syndrome coronavirus 2, which is associated with poor fetal outcomes. The histologic pattern of injury, termed severe acute respiratory syndrome coronavirus 2 placentitis, is characterized by a triad of increased perivillous fibrin deposition, intervillous histiocytes, and trophoblast necrosis. While the etiology of massive perivillous fibrin deposition (MPVFD) is mostly unknown, previous case reports of MPVFD in association with maternal Enterovirus (ENT) suggest that a subset of these cases are a consequence of undiagnosed viral infection. We evaluated 46 placentas collected between 2011 and 2022 with a diagnosis of MPVFD (n = 41) or chronic histiocytic intervillositis (CHI; n = 4). Combining methods of pan-viral metagenomic sequencing and targeted viral PCR, we detected Enterovirus DNA in 8 of 45 (18%) MPVFD and/or CHI cases. Seven of these positive cases were from MPVFD, and 1 was associated with a CHI diagnosis. Enterovirus A species (n = 7) were commonly identified, whereas one case had Enterovirus B. Histologic evaluation of these cases, including immunohistochemical staining for CD68, demonstrated increased intervillous histiocytes in Enterovirus -positive MPVFD cases in comparison with Enterovirus- negative, as well as evidence of trophoblast necrosis. Thus, we favor the terminology Enterovirus placentitis to describe this pathology. Overall, these findings suggest that Enterovirus is an underrecognized etiology of histologic MPVFD and, possibly, CHI. Further study to evaluate the recurrence risk of Enterovirus placentitis in comparison to MPVFD may help inform future fertility planning in patients with these diagnoses.

Infections at the maternal-fetal interface: an overview of pathogenesis and defence

Infections are a major threat to human reproductive health, and infections in pregnancy can cause prematurity or stillbirth, or can be vertically transmitted to the fetus leading to congenital infection and severe disease. The acronym 'TORCH' (Toxoplasma gondii, other, rubella virus, cytomegalovirus, herpes simplex virus) refers to pathogens directly associated with the development of congenital disease and includes diverse bacteria, viruses and parasites. The placenta restricts vertical transmission during pregnancy and has evolved robust mechanisms of microbial defence. However, microorganisms that cause congenital disease have likely evolved diverse mechanisms to bypass these defences. In this Review, we discuss how TORCH pathogens access the intra-amniotic space and overcome the placental defences that protect against microbial vertical transmission.

Are the Organoid Models an Invaluable Contribution to ZIKA Virus Research?

In order to prevent new pathogen outbreaks and avoid possible new global health threats, it is important to study the mechanisms of microbial pathogenesis, screen new antiviral agents and test new vaccines using the best methods. In the last decade, organoids have provided a groundbreaking opportunity for modeling pathogen infections in human brains, including Zika virus (ZIKV) infection. ZIKV is a member of the Flavivirus genus, and it is recognized as an emerging infectious agent and a serious threat to global health. Organoids are 3D complex cellular models that offer an in-scale organ that is physiologically alike to the original one, useful for exploring the mechanisms behind pathogens infection; additionally, organoids integrate data generated in vitro with traditional tools and often support those obtained in vivo with animal model. In this mini-review the value of organoids for ZIKV research is examined and sustained by the most recent literature. Within a 3D viewpoint, tissue engineered models are proposed as future biological systems to help in deciphering pathogenic processes and evaluate preventive and therapeutic strategies against ZIKV. The next steps in this field constitute a challenge that may protect people and future generations from severe brain defects.

Self-assembled raccoon dog parvovirus VP2 protein confers immunity against RDPV disease in raccoon dogs: in vitro and in vivo studies

BACKGROUND

Raccoon dog parvovirus (RDPV) causes acute infectious diseases in raccoon dogs and may cause death in severe cases. The current treatment strategy relies on the extensive usage of classical inactivated vaccine which is marred by large doses, short immunization cycles and safety concerns.

METHODS

The present study aimed at optimization of RDPV VP2 gene, subcloning the gene into plasmid pET30a, and its subsequent transfer to Escherichia coli with trigger factor 16 for co-expression. The protein thus expressed was purified with ammonium sulfate precipitation, hydrophobic chromatography, and endotoxin extraction procedures. VLPs were examined by transmission electron microscopy, dynamic light scattering, and the efficacy of VLPs vaccine was tested in vivo.

RESULTS

Results indicated that RDPV VP2 protein could be expressed soluble. Transmission electron microscopy and dynamic light scattering results indicated that RDPV VP2 self-assembled into VLPs. Hemagglutination inhibition antibody titers elicited by Al(OH)3 adjuvanted RDPV VLPs were comparable with RDPV inactivated vaccines, and the viral loads in the blood of the struck raccoon dogs were greatly reduced. Hematoxylin and eosin and Immunohistochemical results indicated that RDPV VLPs vaccine could protect raccoon dogs against RDPV infections.

CONCLUSIONS

These results suggest that RDPV VLPs can become a potential vaccine candidate for RDPV therapy.

Persistence of Villous Immaturity in Term Deliveries Following Intrauterine Transfusion for Parvovirus B19 Infection and RhD-associated Hemolytic Disease of the Fetus and Newborn

Common causes of fetal anemia and hydrops include parvovirus B19 infection during the first 2 trimesters of pregnancy, as well as maternal alloimmunization to RhD with subsequent hemolytic disease of the fetus and newborn (HDFN) in an RhD positive fetus. Although both of these conditions have historically caused significant fetal morbidity and mortality, the advent of intrauterine transfusion (IUT) over the last few decades has dramatically improved outcomes. Prior literature has extensively documented placental changes associated with untreated parvovirus infection and RhD HDFN in intrauterine fetal demises and preterm births; however, histopathologic changes in term placentas from term infants treated with IUT have not been reported. We present placental findings in 2 cases of parvovirus B19-associated hydrops and 2 cases of RhD HDFN-associated hydrops in term infants after IUT, highlighting unique aspects that may be diagnostically useful for the examining pathologist.

Human bocaviruses: Possible etiologic role in respiratory infection

Four species of human bocaviruses (HBoV) are currently included in the Bocavirus genus. There is satisfactory evidence demonstrating an association between HBoV1 and respiratory disease in children, and there is evidence that HBoV2 (and possibly the HBoV3 and HBoV4 species) are associated with gastroenteritis. In particular, HBoV1 has been associated with a prolonged period of persistence in the mucosa of the respiratory tract. Virus persistence does play a role in the high frequency of co-infections with proper pathogens of the upper and lower respiratory tracts. The high detection rate of multiple respiratory viruses in up to 83% of respiratory specimens and the presence of asymptomatic HBoV1 infections complicate the elucidation of the pathogenic role of the agent. Overall, a large amount of data are available concerning HBoV1, whereas little information is available about other bocavirus species. High viral loads are often associated with symptoms, and viremia may be associated with systemic manifestations such as encephalopathy. The effects and mechanisms of latency, persistence, reactivation, and reinfection are poorly understood. Thus, particularly in co-infections, the pathogenic contribution of the detected bocavirus species cannot be accurately stated. This review summarizes the current knowledge of HBoV species and provides perspectives for future clinical studies.