Central nervous system infections after solid organ transplantation.

PURPOSE OF REVIEW: Significant advances to our understanding of several neuroinfectious complications after a solid organ transplant (SOT) have occurred in the last few years. Here, we review the central nervous system (CNS) infections that are relevant to SOT via a syndromic approach with a particular emphasis on recent updates in the field. RECENT FINDINGS: A few key studies have advanced our understanding of the epidemiology and clinical characteristics of several CNS infections in SOT recipients. Risk factors for poor prognosis and protective effects of standard posttransplant prophylactic strategies have been better elucidated. Newer diagnostic modalities which have broad clinical applications like metagenomic next-generation sequencing, as well as those that help us better understand esoteric concepts of disease pathogenesis have been studied. Finally, several studies have provided newer insights into the treatment of these diseases. SUMMARY: Recent findings reflect the steady progress in our understanding of CNS infections post SOT. They provide several avenues for improvement in the prevention, early recognition, and therapeutic outcomes of these diseases.

Zika virus transmission via breast milk in suckling mice.

OBJECTIVES: Infectious Zika viral particles were detected in human milk; however, whether they can be transmitted via breastfeeding remains unknown, so our objective was to clarify this. METHODS: Here, in a natural breastfeeding model, wild-type (C57Bl/6; WT) or interferon α/ß (IFNα/ß) receptor-deficient (A129; KO) murine dams on day 1 post-delivery were infected with Zika virus (ZIKV) intraperitoneally, and the neonates were suckled. In a novel artificial feeding model, WT suckling mice at 1 day old were fed with ZIKV alone or ZIKV and human breast milk mixtures. Thereafter, the virus distribution, clinical progression and neuropathology in the WT or KO neonates were characterized to evaluate the risk of ZIKV transmission through breast milk. RESULTS: In natural breastfeeding, viral RNAs (8/8) and infectious viral particles (7/8) were extensively present in the mammary glands of KO dams. All tested KO neonates (5/5), and none of WT neonates (0/9), were infected with ZIKV. In artificial feeding, 100% of the WT neonates (two groups, 12/12 and 16/16) were infected and developed some signs of neurodegeneration. ZIKV tended to seed and accumulate in the lungs and were subsequently disseminated to other tissues in both 16 naturally suckled and 19 artificially fed infected neonates. As human breast milk was mixed with ZIKV and fed to WT neonates, 45% individuals (9/20) were infected; in the infected neonates, the viral spread to the brain was delayed, and the clinical outcomes were alleviated. CONCLUSIONS: These results demonstrated that suckling mice can be infected with ZIKV through suckling, and breast milk has potential antiviral activity, inhibiting ZIKV infection.

Pathogens penetrating the central nervous system: infection pathways and the cellular and molecular mechanisms of invasion.

The brain is well protected against microbial invasion by cellular barriers, such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). In addition, cells within the central nervous system (CNS) are capable of producing an immune response against invading pathogens. Nonetheless, a range of pathogenic microbes make their way to the CNS, and the resulting infections can cause significant morbidity and mortality. Bacteria, amoebae, fungi, and viruses are capable of CNS invasion, with the latter using axonal transport as a common route of infection. In this review, we compare the mechanisms by which bacterial pathogens reach the CNS and infect the brain. In particular, we focus on recent data regarding mechanisms of bacterial translocation from the nasal mucosa to the brain, which represents a little explored pathway of bacterial invasion but has been proposed as being particularly important in explaining how infection with Burkholderia pseudomallei can result in melioidosis encephalomyelitis.

Solid organ transplant donors with central nervous system infection.

BACKGROUND: While donor-derived infections (DDI) remain uncommon, multiple reports describe DDI with pathogens that cause central nervous system (CNS) infection resulting in significant recipient disease. The Ad Hoc Disease Transmission Advisory Committee (DTAC) reviewed the records of potential donor-derived disease transmission events (PDDTE) to describe donor characteristics and outcomes associated with DDI from CNS pathogens. METHODS: All PDDTE reported from January 2008 to September 2010 were reviewed for characteristics suggesting CNS infection in the donor or the recipient. Identified cases were further examined to determine if donor CNS infection resulted in recipient infection. RESULTS: Ninety-one PDDTE cases in which there was concern for CNS infection in the donor or recipient were identified. Further review confirmed CNS infection in 12 donors, six of whom transmitted infection to 10 of 15 exposed recipients with five recipient deaths. Pathogens included Balamuthia mandrillaris, Cryptococcus neoformans, lymphocytic choriomeningitis virus, and West Nile virus. Listed cause of death at procurement for these donors included stroke, anoxia, acute disseminated encephalomyelitis, and meningoencephalitis. Confounding diagnoses were present in 6 of 12 donors that would have allowed them to be considered at low risk of transmitting a CNS pathogen. Of the six donors with no confounding conditions, three exhibited at least two suspicious "DTAC warning criteria" for CNS infection. CONCLUSION: Careful clinical assessment of donors combined with a high index of suspicion for ambiguous or misleading findings associated with CNS infection can reduce, but not eliminate, DDI with CNS pathogens.

Emerging viral infections of the central nervous system: part 1.

In this 2-part review, I will focus on emerging virus infections of the central nervous system (CNS). Part 1 will introduce the basic features of emerging infections, including their definition, epidemiology, and the frequency of CNS involvement. Important mechanisms of emergence will be reviewed, including viruses spreading into new host ranges as exemplified by West Nile virus (WNV), Japanese encephalitis (JE) virus, Toscana virus, and enterovirus 71 (EV71). Emerging infections also result from opportunistic spread of viruses into known niches, often resulting from attenuated host resistance to infection. This process is exemplified by transplant-associated cases of viral CNS infection caused by WNV, rabies virus, lymphocytic choriomeningitis, and lymphocytic choriomeningitis-like viruses and by the syndrome of human herpesvirus 6 (HHV6)-associated posttransplantation acute limbic encephalitis. The second part of this review begins with a discussion of JC virus and the occurrence of progressive multifocal leukoencephalopathy in association with novel immunomodulatory therapies and then continues with an overview of the risk of infection introduced by imported animals (eg, monkeypox virus) and examples of emerging diseases caused by enhanced competence of viruses for vectors and the spread of vectors (eg, chikungunya virus) and then concludes with examples of novel viruses causing CNS infection as exemplified by Nipah and Hendra viruses and bat lyssaviruses.

[Central nervous system lesions in fetuses and newborns in intrauterine infection caused by respiratory viruses]. / Porazheniia tsentral'noi nervnoi sistemy plodov i novorozhdennykh pri vnutriutrobnoi infektsii, vyzvannoi respiratornymi virusami.

Congenital respiratory viral infection is followed in the CNS of fetuses and newborns by grave dyscirculatory disturbances with glia proliferation and nervous tissue edema. The process is mainly localized in the periventricular regions of the brain ventricles. Neurologic and morphologic consequences of these damages in the CNS of fetuses and newborns need further studies.

Principles and practice of 'high risk' brain banking.

The storage of tissues obtained from patients with clinically documented and neuropathologically validated diseases of the central nervous system (CNS), and from well-chosen control cases, forms a valuable resource for present and future research needs. In particular, it facilitates immediate application of new investigative technology as this becomes available. To maximize their usefulness it is desirable to store tissues in a variety of different forms, including fixed and frozen samples. However, storage of infective dementias poses special problems (including risk to future users) since the infective agent may well survive long-term storage at -70 degrees C. Guidelines for optimal storage of such tissues should conform with safety, but should not be so prescriptive as to deter pathologists who do not have access to sophisticated brain banking resources. This article provides information about tissue storage from infective CNS diseases for pathologists who may require to retain frozen and other samples from such autopsies either occasionally or on a regular basis. Guidelines are offered for banking tissues from cases infected with human immunodeficiency virus (HIV), hepatitis viruses and prions. With detailed description of procedures for acquisition, storage and transparent of high-risk samples. Safety issues and protocols for response to accidental injury involving exposure to these agents are highlighted in this article.