Long-term impact of intrauterine MCMV infection on development of offspring nervous system

Impairment in neurocognitive function following experimental neonatal guinea pig cytomegalovirus infection

BACKGROUND

Cytomegalovirus (CMV) is a leading infectious cause of neurologic deficits, both in the settings of congenital and perinatal infection, but few animal models exist to study neurodevelopmental outcomes. This study examined the impact of neonatal guinea pig CMV (GPCMV) infection on spatial learning and memory in a Morris water maze (MWM) model.

METHODS

Newborn pups were challenged intraperitoneally (i.p.) with a pathogenic red fluorescent protein-tagged GPCMV, or sham inoculated. On days 15-19 post infection (p.i.), pups were tested in the MWM. Viral loads were measured in blood and tissue by quantitative PCR (qPCR), and brain samples collected at necropsy were examined by histology and immunohistochemistry.

RESULTS

Viremia (DNAemia) was detected at day 3 p.i. in 7/8 challenged animals. End-organ dissemination was observed, by qPCR, in the lung, liver, and spleen. CD4-positive (CD4+) and CD8-positive (CD8+) T cell infiltrates were present in brains of challenged animals, particularly in periventricular and hippocampal regions. Reactive gliosis and microglial nodules were observed. Statistically significant spatial learning and memory deficits were observed by MWM, particularly for total maze distance traveled (p < 0.0001).

CONCLUSION

Neonatal GPCMV infection in guinea pigs results in cognitive defects demonstrable by the MWM. This neonatal guinea pig challenge model can be exploited for studying antiviral interventions.

IMPACT

CMV impairs neonatal neurocognition and memory in the setting of postnatal infection. The MWM can be used to examine memory and learning in a guinea pig model of neonatal CMV infection. CD4+ and CD8+ T cells infiltrate the brain following neonatal CMV challenge. This article demonstrates that the MWM can be used to evaluate memory and learning after neonatal GPCMV challenge. The guinea pig can be used to examine central nervous system pathology caused by neonatal CMV infection and this attribute may facilitate the study of vaccines and antivirals.

Zika Virus Causes Persistent Infection in Porcine Conceptuses and may Impair Health in Offspring

Outcomes of Zika virus (ZIKV) infection in pregnant women vary from the birth of asymptomatic offspring to abnormal development and severe brain lesions in fetuses and infants. There are concerns that offspring affected in utero and born without apparent symptoms may develop mental illnesses. Therefore, animal models are important to test interventions against in utero infection and health sequelae in symptomatic and likely more widespread asymptomatic offspring. To partially reproduce in utero infection in humans, we directly inoculated selected porcine conceptuses with ZIKV. Inoculation resulted in rapid trans-fetal infections, persistent infection in conceptuses, molecular pathology in fetal brains, fetal antibody and type I interferon responses. Offspring infected in utero showed ZIKV in their fetal membranes collected after birth. Some in utero affected piglets were small, depressed, had undersized brains, and showed seizures. Some piglets showed potentially increased activity. Our data suggest that porcine model of persistent in utero ZIKV infection has a strong potential for translational research and can be used to test therapeutic interventions in vivo.

Intrauterine Zika virus infection of pregnant immunocompetent mice models transplacental transmission and adverse perinatal outcomes

Zika virus (ZIKV) crosses the placenta and causes congenital disease. Here we develop an animal model utilizing direct ZIKV inoculation into the uterine wall of pregnant, immunocompetent mice to evaluate transplacental transmission. Intrauterine inoculation at embryonic day (E) 10, but not E14, with African, Asian or American strains of ZIKV reduces fetal viability and increases infection of placental and fetal tissues. ZIKV inoculation at E10 causes placental inflammation, placental dysfunction and reduces neonatal brain cortical thickness, which is associated with increased activation of microglia. Viral antigen localizes in trophoblast and endothelial cells in the placenta, and endothelial, microglial and neural progenitor cells in the fetal brain. ZIKV infection of the placenta increases production of IFNβ and expression of IFN-stimulated genes 48 h after infection. This mouse model provides a platform for identifying factors at the maternal-fetal interface that contribute to adverse perinatal outcomes in a host with an intact immune system.

Developing a Vaccine against Congenital Cytomegalovirus (CMV) Infection: What Have We Learned from Animal Models? Where Should We Go Next?

Congenital human cytomegalovirus (HCMV) infection can lead to long-term neurodevelopmental sequelae, including mental retardation and sensorineural hearing loss. Unfortunately, CMVs are highly adapted to their specific species, precluding the evaluation of HCMV vaccines in animal models prior to clinical trials. Several species-specific CMVs have been characterized and developed in models of pathogenesis and vaccine-mediated protection against disease. These include the murine CMV (MCMV), the porcine CMV (PCMV), the rhesus macaque CMV (RhCMV), the rat CMV (RCMV), and the guinea pig CMV (GPCMV). Because of the propensity of the GPCMV to cross the placenta, infecting the fetus in utero, it has emerged as a model of particular interest in studying vaccine-mediated protection of the fetus. In this paper, a review of these various models, with particular emphasis on the value of the model in the testing and evaluation of vaccines against congenital CMV, is provided. Recent exciting developments and advances in these various models are summarized, and recommendations offered for high-priority areas for future study.

Congenital cytomegalovirus infection in fraternal twins: a longitudinal case study examining neurocognitive and neurobehavioral correlates

Cytomegalovirus (CMV) is the most ubiquitous member of the herpes virus family and is the leading cause of congenital (vertical) infection in newborns (Fowler, Stagno, & Pass, 2003; Llorente, Steigmeyer, Cooper, Rivers, & Gazley, 2011; Noyola et al., 2000; Steigmeyer & Llorente, 2010). CMV is related to the group of viruses capable of causing more pernicious infectious diseases, such as chicken pox (Santos de Barona, 1998). Although the virus generally remains dormant, individuals whose symptoms are clinically apparent often are dramatically affected. Common symptomatic characteristics of the virus include microcephaly, jaundice, liver-spleen infections, pneumonia, cardiac anomalies, chorioretinitis, vision loss, sensory-neural hearing loss, mental retardation, and mononucleosis (Demmler, 1991; Kashden, Frison, Fowler, Pass, & Boll, 1998; Noyola et al., 2000; Pass, 2005; Santos de Barona). The prognosis of individuals with CMV is highly variable, and the prognosis of individuals with congenital CMV can usually be determined based on the extent of infection at birth. The purpose of this investigation is to present longitudinal results of neuropsychological evaluation of two dizygotic twin sets (one twin of each set is asymptomatic CMV-positive and the other is uninfected) who were reared in the same environment. In addition, the present findings are discussed within the context of emerging murine and other animal analogues of CMV as well as within the extant CMV literature.

Viral Infections of Laboratory Mice

Viral infections of laboratory mice have considerable impact on research results, and prevention of such infections is therefore of crucial importance. This chapter covers infections of mice with the following viruses: herpesviruses, mousepox virus, murine adenoviruses, polyomaviruses, parvoviruses, lactate dehydrogenase-elevating virus, lymphocytic choriomeningitis virus, mammalian orthoreovirus serotype 3, murine hepatitis virus, murine norovirus, murine pneumonia virus, murine rotavirus, Sendai virus, and Theiler’s murine encephalomyelitis virus. For each virus, there is a description of the agent, epizootiology, clinical symptoms, pathology, methods of diagnosis and control, and its impact on research.