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Biology subjects

Panganiban, A.

Publications and source records attributed to Panganiban, A..

3 recordsLinked to original sources

Zika virus persistence in the male macaque reproductive tract

Zika virus (ZIKV) is unique among mosquito-borne flaviviruses in that it is also vertically and sexually transmitted by humans. The male reproductive tract is thought to be a ZIKV reservoir; however, the reported magnitude and duration of viral persistence in male genital tissues varies widely in humans and non-human primate models. ZIKV tissue and cellular tropism and potential effects on male fertility also remain unclear. The objective of this study was to resolve these questions by analyzing archived genital tissues from 51 ZIKV-inoculated male macaques and correlating data on plasma viral kinetics, tissue tropism, and ZIKV-induced pathological changes in the reproductive tract. We hypothesized that ZIKV would persist in the male macaque genital tract for longer than there was detectable viremia, where it would localize to germ and epithelial cells and associate with lesions. We detected ZIKV RNA and infectious virus in testis, epididymis, seminal vesicle, and prostate gland. In contrast to prepubertal males, sexually mature macaques were significantly more likely to harbor persistent ZIKV RNA or infectious virus somewhere in the genital tract, with detection as late as 60 days post-inoculation. ZIKV RNA localized primarily to testicular stem cells/sperm precursors and epithelial cells, including Sertoli cells, epididymal duct epithelium, and glandular epithelia of the seminal vesicle and prostate gland. ZIKV infection was associated with microscopic evidence of inflammation in the epididymis and prostate gland of sexually mature males, which could have significant effects on male fertility. The findings from this study increase our understanding of persistent ZIKV infection which can inform risk of sexual transmission during assisted reproductive therapies as well as potential impacts on male fertility. Author SummaryZika virus (ZIKV) spread since 2015 led to establishment of urban epidemic cycles involving humans and Aedes mosquitoes. ZIKV is also sexually and vertically transmitted and causes congenital Zika syndrome. Together, these features show that ZIKV poses significant global public health risks. By virtue of similar reproductive anatomy and physiology to humans, macaques serve as a useful model for ZIKV infection. However, macaque studies to date have been limited by small sample size, typically 1 to 5 animals. Although mounting evidence identifies the male reproductive tract as a significant ZIKV reservoir, data regarding the duration of ZIKV persistence, potential for sexual transmission, and male genitourinary sequelae remain sparse. Here, we analyzed archived genital tissues from more than 50 ZIKV-inoculated male macaques. Our results show that ZIKV can persist in the male macaque reproductive tract after the resolution of viremia, with virus localization to sperm precursors and epithelial cells, and microscopic evidence of inflammation in the epididymis and prostate gland. Additionally, we show that freezing is not a viable method of destroying infectious ZIKV. Our findings help explain cases of sexual transmission of ZIKV in humans, which also carries a risk for transmission via assisted fertility procedures, even after resolution of detectable viremia.

pathology↗

A Zika Virus Primary Isolate Induces Neuroinflammation, Compromises the Blood-Brain Barrier, and Upregulates CXCL12 in Adult Macaques

Zika virus (ZIKV) is a neurotropic virus that can cause neuropathy in adults and fetal neurologic malformation following infection of pregnant women. We used a nonhuman primate model, the Indian-origin Rhesus macaque (IRM), to gain insight into virus-associated hallmarks of ZIKV-induced adult neuropathy. We find that the virus causes prevalent acute and chronic neuroinflammation and chronic disruption of the blood-brain barrier (BBB) in adult animals. Infection results in significant, targeted, and sustained upregulation of the chemokine, CXCL12, in the central nervous system (CNS). CXCL12 plays a key role both in regulating lymphocyte trafficking through the BBB to the CNS, and in mediating repair of damaged neural tissue including remyelination. Understanding how CXCL12 expression is controlled will likely be of central importance in the definition of ZIKV-associated neuropathy in adults. Author summaryZika virus (ZIKV) is a virus that can cause neurological problems in adults and damage to the fetal brain. Nonhuman primates (NHPs) are usually superior animal models for recapitulating human neurological disease because their brain, nervous system structure and immune response to virus infection are very similar to that of humans. We have studied the effect of ZIKV infection on the adult NHP brain and made several significant observations. Infection resulted in a high incidence of mild to moderate brain inflammation that persisted for a surprisingly long period of time. We also found that the virus disrupted the blood brain barrier, which is important for controlling transport of material from blood to the brain. It appears that the central nervous system expresses a specific substance in response to virus infection called a chemokine. This specific chemokine may be involved in virus-induced inflammation and/or in repair of virus-induced brain damage. Our data are significant since they help in understanding the mechanism of brain damage caused by ZIKV in adults.

microbiology↗

Maternal antibodies provide partial protection from postnatal Zika viremia in nonhuman primates

Zika virus (ZIKV) will remain a public health threat until effective vaccines and therapeutics are made available in the hardest hit areas of the world. Recent data in a nonhuman primate model showed that infants postnatally infected with ZIKV were acutely susceptible to high viremia and neurological damage, suggesting the window of vulnerability extends beyond gestation. We addressed the susceptibility of two infant rhesus macaques born healthy to dams infected with Zika virus during pregnancy. Passively acquired neutralizing antibody titers dropped below detection limits between 2 and 3 months of age, while binding, possibly non-neutralizing antibodies remained detectable until viral infection at 5 months of age. Post-infection acute serum viremia was substantially reduced relative to adults infected with the same dose of the same stock of a Brazilian isolate of ZIKV (n=11 pregnant females) and another stock of the same isolate (n=4 males and 4 non-pregnant females). Virus was never detected in cerebrospinal fluid nor in neural tissues at necropsy two weeks after infection, suggesting reduced viral burden relative to adults and published data from infants. However, viral RNA was detected in lymph nodes, confirming some tissue dissemination. Though protection was not absolute, our data suggest infants born healthy to infected mothers may harbor a modest but important level of protection from postnatally acquired ZIKV for several months after birth, an encouraging result given the potentially severe infection outcomes of this population.

microbiology↗