Excretion of Cell-Free and Cell-Associated Zika Virus into Breast Milk of Infected Dams and Identification of Antiviral Factors

Zika virus (ZIKV) is a mosquito-borne RNA virus belonging to the Flavivirus genus of the Flaviviridae family. During the 60 years following its discovery in 1947, ZIKV caused little concern for public health as the associated infection was reported as mostly asymptomatic or inducing mild symptoms. However, since 2013, severe neurological symptoms have been associated with ZIKV infection, compelling the World Health Organization to declare a Public Health Emergency of International Concern. Among those symptoms, neurological birth defects may affect children born to mothers infected during pregnancy. Additionally, during the past 8 years, ZIKV transmission through breastfeeding has repeatedly been suggested in epidemiological studies and demonstrated on a mouse model by our team. To better understand the biological factors controlling ZIKV transmission through breastfeeding, we investigated the nature of the viral entities excreted in the breast milk of infected dams and evaluated viral transmission to breastfed pups. We show that both cell-free and cell-associated virus is excreted into breast milk and that ZIKV is efficiently transmitted to the breastfed pups. Additionally, we studied murine breast milk cell types, and identified a majority of mammary luminal cells. Finally, we investigated the effect on ZIKV infectivity of several breast milk components that are antiviral against different viruses such as lactoferrin (LF) and lactalbumin (LA), or free fatty acids (FFA). We showed no effect of LF and LA, whereas FFA inactivated the virus. These results bring new insight concerning the mechanisms of ZIKV transmission during breastfeeding and identify biological factors modulating it. These elements should be considered in risk assessment of ZIKV mother-to-child transmission.     

Infant Feeding Practices were not Associated with Breast Milk HIV-1 RNA Levels in a Randomized Clinical Trial in Botswana

Exclusive breastfeeding has been associated with a reduced risk of late vertical HIV transmission as compared to an infant diet composed of breast milk mixed with supplemental foods or liquids. Hypothesized mechanisms include increased infectivity of breast milk from mothers who practice mixed breastfeeding (MBF), or mechanisms such as increased gastrointestinal permeability in the infant caused by mixed feeding. It has been proposed that MBF may result in subclinical mastitis and higher breast milk HIV titers. However, little is known about the relationship between feeding strategy and breast milk viral load. We measured the HIV-1 concentration in breast milk in a sub-cohort of women enrolled in a mother-to-child HIV transmission prevention trial (the "Mashi" study). We report no observed relationship between MBF and measured breast milk viral RNA load. Our findings suggest that the increased transmission risk associated with higher breast milk HIV-1 RNA during MBF is unlikely.     

Zika病毒:虫媒病毒传染病的新挑战

Zika病毒(Zika virus,ZIKV)是一种新发的虫媒病毒,伊蚊是其主要的传播媒介。Zika病毒感染后主要引起发热,皮疹,关节痛等轻症症状。2015年起,Zika病毒在拉丁美洲及南美洲多个国家流行,并且Zika病毒感染患者不仅出现发热,皮疹和关节痛等症状,还发现Zika病毒病的流行与婴儿小头畸形,格林巴利综合征,病毒性脑膜炎病例的发生相关。不仅如此,Zika病毒感染还可以通过性途径传播。因此,从病毒感染症状的复杂性来看,目前流行的Zika病毒已经与1947年刚发现时的Zika病毒完全不同,而是成为了一种“新病毒”。 本文系统地梳理总结了Zika病毒感染相关的最新研究进展,并提出Zika病毒及其感染是对虫媒病毒传染病的新挑战的概念。     

Zika Virus Antibody Titers Three Years after Confirmed Infection

Background: In 2015–2016, a large Zika virus (ZIKV) outbreak occurred in the Americas. Although the exact ZIKV antibody kinetics after infection are unknown, recent evidence indicates the rapid waning of ZIKV antibodies in humans. Therefore, we aimed to determine the levels of ZIKV antibodies more than three years after a ZIKV infection. Methods: We performed ZIKV virus neutralization tests (VNT) and a commercial ZIKV non-structural protein 1 (NS1) IgG ELISA in a cohort of 49 participants from Suriname who had a polymerase-chain-reaction-confirmed ZIKV infection more than three years ago. Furthermore, we determined the presence of antibodies against multiple dengue virus (DENV) antigens. Results: The ZIKV seroprevalence in this cohort, assessed with ZIKV VNT and ZIKV NS1 IgG ELISA, was 59.2% and 63.3%, respectively. There was, however, no correlation between these two tests. Furthermore, we did not find evidence of a potential negative influence of DENV immunity on ZIKV antibody titers. Conclusions: ZIKV seroprevalence, assessed with two commonly used serological tests, was lower than expected in this cohort of participants who had a confirmed previous ZIKV infection. This can have implications for future ZIKV seroprevalence studies and possibly for the duration of immunological protection after a ZIKV infection.     

Pregnant Women Infected with Zika Virus Show Higher Viral Load and Immunoregulatory Cytokines Profile with CXCL10 Increase

Background: Zika virus (ZIKV) infection during pregnancy usually shows only mild symptoms and is frequently subclinical. However, it can be vertically transmitted to the fetus, causing microcephaly and other congenital defects. During pregnancy, the immune environment modifications can alter the response to viruses in general and ZIKV in particular. Objective: To describe the role of pregnancy in the systemic pro- and anti-inflammatory response during symptomatic ZIKV infection. Materials and Methods: A multiplex assay was used to measure 25 cytokines, chemokines, and receptors in 110 serum samples from pregnant and nonpregnant women with and without ZIKV infection with and without symptoms. Samples were collected through an epidemiological surveillance system. Results: Samples from pregnant women with ZIKV infection showed a higher viral load but had similar profiles of inflammatory markers as compared with nonpregnant infected women, except for CXCL10 that was higher in infected pregnant women. Notably, the presence of ZIKV in pregnancy favored a regulatory profile by significantly increasing anti-inflammatory cytokines such as interleukin (IL)-10, receptors IL-1RA, and IL-2R, but only those pro-inflammatory cytokines such as IL-6, interferon (IFN)-α, IFN-γ and IL-17 that are essential for the antiviral response. Interestingly, there were no differences between symptomatic and weakly symptomatic ZIKV-infected groups. Conclusion: Our results revealed a systemic anti-inflammatory cytokine and chemokine profile that could participate in the control of the virus. The anti-inflammatory response in pregnant women infected with ZIKA was characterized by high CXCL10, a cytokine that has been correlated with congenital malformations.     

输血传播病毒母婴传播的研究

目的：探讨深圳市孕产妇输血传播病毒（TTV）感染情况及其在母婴间的传播途径。方法：应用套式－聚合酶链反应（Nest－PCR）对400例正常孕产妇分娩前的血清及其新生儿的脐血血清标本、产妇的乳汁配对进行了TTV DNA检测，对阳性的母亲及其新生儿进行的6个月随访，并对其中13对TTV DNA阳性的母血、母乳及其婴儿的血，共做32株克隆，通过DNA序列测定比较分析母婴TTV感染株之间核苷酸的序列同源性。结果：在400对配对标本中，62例孕妇血清、4例新生儿脐血清、20例母乳检测出TTV DNA，孕母TTV感染率15．5％（62／400），出生时母婴TTV传播率6．5％（4／62），阳性母亲乳TTV DNA检出率32．2％（20／62），配对比较母婴间TTV感染株序列同源性为97．4％－99．8％，经6个月随访母血TTV DNA阳性的婴儿血TTV DNA由阴转阳率为38．1％（16／42）。 结论：TTV可通过围产期和哺乳期母婴传播的途径感染，对胎儿的危害及新生儿生长发育的影响值得重视。     

Seroprevalence of Zika Virus in Amphawa District,Thailand, after the 2016 Pandemic

In 2016, Zika virus (ZIKV) infection was declared a public health emergency of international concern because of the neurological consequences in babies born to infected people. Because of the mild and nonspecific symptoms, serological tests are essential in epidemiological studies. However, cross-reactive antibodies between other Flaviviridae members may complicate the interpretation of results of these tests. This study investigated the seroprevalence of ZIKV infection in Samut Songkhram in central Thailand which was affected by the Zika outbreak of 2016. Three hundred and fifty volunteers aged 5–50 years in Amphawa District, Samut Songkhram, were enrolled between April 2017 and April 2018. ZIKV nonstructural protein 1 (NS1) immunoglobulin G enzyme-linked immunosorbent assay (ELISA) was used to screen serum samples collected on the first day of enrollment and after 6 and 12 months. The seroprevalence and seroconversion of ZIKV were assessed. Cases of ZIKV seroconversion were verified as evidence of ZIKV infection by NS1 blockade-of-binding ELISA and plaque reduction neutralization test (PRNT50). ZIKV seroprevalence in Amphawa was 15.1–17.8% with no significant change over the year. The total seroconversion rate throughout the year was 7/100 person-years. The ratio of asymptomatic to symptomatic infections was 4.5:1. The cases in our study confirmed the occurrence of occult ZIKV infections in the community. These undetected infections might promote the spread of ZIKV in vulnerable groups of the community.     

Lack of Association between Adverse Pregnancy Outcomes and Zika Antibodies among Pregnant Women in Thailand between 1997 and 2015

Data about Zika virus infection and adverse pregnancy outcomes in Southeast Asia are scarce. We conducted an unmatched case-control study of Zika virus (ZIKV) serology in pregnant women enrolled in human immunodeficiency virus (HIV) or hepatitis B virus (HBV) perinatal prevention trials between 1997 and 2015 in Thailand. Case and control groups included women with and without adverse pregnancy outcomes. Plasma samples collected during the last trimester of pregnancy were tested for ZIKV IgG/IgM and Dengue IgG/IgM (Euroimmun, AG, Germany). Case newborn plasma samples were tested for ZIKV IgM and ZIKV RNA (Viasure, Spain). The case group included women with stillbirth (n = 22) or whose infants had microcephaly (n = 4), a head circumference below the first percentile (n = 14), neurological disorders (n = 36), or had died within 10 days after birth (n = 11). No women in the case group were positive for ZIKV IgM, and none of their live-born neonates were positive for ZIKV IgM or ZIKV RNA. The overall ZIKV IgG prevalence was 29%, 24% in the case and 34% in the control groups (Fisher’s exact test; p = 0.13), while the dengue IgG seroprevalence was 90%. Neither neonatal ZIKV infections nor ZIKV-related adverse pregnancy outcomes were observed in these women with HIV and/or HBV during the 18-year study period.     

Breastfeeding to prevent HIV transmission in infants: balancing pros and cons

PURPOSE OF REVIEW: In industrialized countries avoidance of breastfeeding is among the cornerstones of prevention of mother-to-child transmission of HIV. Breastfeeding carries risk for HIV transmission but improves survival, whereas formula feeding carries zero risk for transmission but increased risk for mortality. We assesses breastfeeding is a rational and viable option for HIV-infected women in poor environments. RECENT FINDINGS: A number of recent studies, mostly from Africa, have provided new data that enable health workers to offer HIV-positive women clear advice on infant feeding appropriate to their individual circumstances. The studies are grouped according to whether the evidence favours one or other feeding type and are considered under the following headings: equivalence of formula feeding and breastfeeding; breastfeeding, HIV disease progression and mortality in mothers; breast superior to formula; breastfeeding for HIV-infected babies; and reducing risk for transmission while breastfeeding. SUMMARY: The weight of current evidence favours exclusive breastfeeding for 6 months to prevent mother-to-child HIV transmission for most HIV-infected mothers globally, most of whom live in poor communities; exclusive breastfeeding may also benefit HIV-infected babies. Formula feeding appears to be equivalent to breastfeeding in terms of survival and transmission risk during the first 2 years of life in some settings.     

Low adherence to recommended infant feeding strategies among HIV-infected women: results from the pilot phase of a randomized trial to prevent mother-to-child transmission in Botswana.

Little is known about the ability of women to adhere to recommended feeding strategies to prevent mother-to-child HIV transmission (MTCT) from breast milk. We conducted a pilot study in rural Botswana to prevent MTCT from breast milk. Women were randomized to formula feed their infants or to exclusively breastfeed while providing prophylactic zidovudine. Women who chose to formula feed independently were also followed. Among those with > or = 3 postpartum visits, none of 31 women assigned to breastfeed did so exclusively for 5 months. Seven (22%) of 32 women in the formula arm definitely or probably breastfed by self-report or as witnessed in maternity, and evidence of breast milk on physical examination was present in 50% of women in > or = 2 visits beyond 1 month. Three (18%) of 17 women choosing formula definitely or probably breastfed, and breast milk was present on exam in 53%. We conclude that adherence to 5 months of exclusive breastfeeding did not occur, and that adherence to exclusive formula feeding was sub-optimal and potentially over reported. Breast examination may be a useful adjunct to self-report, but needs to be validated and standardized. Low adherence to infant feeding strategies that differ from local norms will reduce their effectiveness in preventing MTCT.     

Knowledge of Zika Virus Transmission and Its Prevention among High-Risk Pregnant Women in Brazil

Recent outbreaks of Zika virus (ZIKV) infection highlight the urgent need to evaluate the efficacy of current public health measures to educate susceptible groups about how to prevent infection, modes of viral transmission, and consequences of infection. We performed a cross-sectional study in the city of Jundiaí, São-Paulo, from March 2016 to August 2017. In 315 high-risk pregnant women we evaluated the rate of ZIKV infection, knowledge of pathways of ZIKV transmission, and the use of protective measures. Data were analyzed and correlated with sociodemographic variables. The rate of ZIKV infection was 10.8%. ZIKV transmission by mosquitoes was the best-known means of virus acquisition, while transmission of ZIKV by sexual intercourse as well as mother–fetus transmission was known by less than half of the women. The use of insect repellent, reported by 53% of participants, was correlated with higher education and personal directives from health professionals. Condom use was reported by 19.5% of subjects. Improved strategies to increase awareness of ZIKV infection and its consequences, designed to appeal to specific, targeted populations, are clearly necessary to more accurately prevent the spread of this infection and diminish adverse consequences in the pregnant population.     

Involvement of Th1Th17 Cell Subpopulations in the Immune Responses of Mothers Who Gave Birth to Children with Congenital Zika Syndrome (CZS)

High levels of T helper 17 cell (Th17)-related cytokines have been shown in acute Zika virus (ZIKV) infection. We hypothesized that the high levels of Th17-related cytokines, associated with a regulatory environment during pregnancy, create a favorable milieu for the differentiation of CD4+Th17 cells. We present data from a cross-sectional study on mothers who confirmed ZIKV infection by qRT-PCR and their children. We also recruited non-pregnant women infected with ZIKV in the same period. ZIKV infection occurred between 2015 and 2017. We collected samples for this study between 2018 and 2019, years after the initial infection. We highlight that, after in vitro stimulation with ZIKV CD4 megapool (ZIKV MP), we found a lower frequency of IL-17-producing CD4+ T cells (Th17), especially in the mothers, confirmed by the decrease in IL-17 production in the supernatant. However, a higher frequency of CD4+ IL-17+ IFN-γ+ T cells (Th1Th17) responding to the ZIKV MP was observed in the cells of the mothers and children but not in those of the non-pregnant women. Our data indicate that the priming of CD4 T cells of the Th1Th17 phenotype occurred preferentially in the mothers who gave birth to children with CZS and in the children.     

USP38 Inhibits Zika Virus Infection by Removing Envelope Protein Ubiquitination

Zika virus (ZIKV) is a mosquito-borne flavivirus, and its infection may cause severe neurodegenerative diseases. The outbreak of ZIKV in 2015 in South America has caused severe human congenital and neurologic disorders. Thus, it is vitally important to determine the inner mechanism of ZIKV infection. Here, our data suggested that the ubiquitin-specific peptidase 38 (USP38) played an important role in host resistance to ZIKV infection, during which ZIKV infection did not affect USP38 expression. Mechanistically, USP38 bound to the ZIKV envelope (E) protein through its C-terminal domain and attenuated its K48-linked and K63-linked polyubiquitination, thereby repressed the infection of ZIKV. In addition, we found that the deubiquitinase activity of USP38 was essential to inhibit ZIKV infection, and the mutant that lacked the deubiquitinase activity of USP38 lost the ability to inhibit infection. In conclusion, we found a novel host protein USP38 against ZIKV infection, and this may represent a potential therapeutic target for the treatment and prevention of ZIKV infection.     

From Mosquito Bites to Sexual Transmission: Evaluating Mouse Models of Zika Virus Infection

Following the recent outbreak of Zika virus (ZIKV) infections in Latin America, ZIKV has emerged as a global health threat due to its ability to induce neurological disease in both adults and the developing fetus. ZIKV is largely mosquito-borne and is now endemic in many parts of Africa, Asia, and South America. However, several reports have demonstrated persistent ZIKV infection of the male reproductive tract and evidence of male-to-female sexual transmission of ZIKV. Sexual transmission may broaden the reach of ZIKV infections beyond its current geographical limits, presenting a significant threat worldwide. Several mouse models of ZIKV infection have been developed to investigate ZIKV pathogenesis and develop effective vaccines and therapeutics. However, the majority of these models focus on mosquito-borne infection, while few have considered the impact of sexual transmission on immunity and pathogenesis. This review will examine the advantages and disadvantages of current models of mosquito-borne and sexually transmitted ZIKV and provide recommendations for the effective use of ZIKV mouse models.     

Knowledge of HIV transmission through breast milk among drug-dependent pregnant women

Abstract The current study examined the correlates of knowledge about human immunodeficiency virus (HIV) transmission through breast milk among drug-dependent pregnant women. There is a tremendous need to examine the knowledge about HIV transmission through breastfeeding among this largely understudied, but high-risk subset of pregnant women in order to minimize the extent to which they pass HIV to their children after giving birth. Participants included 97 pregnant women from Baltimore, MD, USA. Prevalence of drug use over the last 6 months included 37.1% reporting smoking marijuana, 36.1% injecting heroin, and 67.0% smoking crack. When asked whether HIV could be transmitted through breast milk, 72 women (74.2%) answered correctly. Our results indicate that the overall knowledge about transmission through breast milk is relatively low. Furthermore, participants who smoked crack during the past 6 months and participants who were white were significantly less likely to have correct knowledge about this topic. Our findings have important implications with regard to preventive interventions for this population. Future research is needed to determine how to best modify these interventions to address the specific needs of drug-dependent pregnant women, and how to specifically target white women and women who smoke crack.     

The management of HCV infected pregnant women and their children European paediatric HCV network

BACKGROUND/AIMS: As evidence accumulates relating to mother-to-child (vertical) transmission of hepatitis C virus (HCV), it is timely to draw up guidelines for the clinical management of HCV infected pregnant women and their children. METHODS: A review of evidence from the European Paediatric HCV Network (EPHN) prospective study of HCV infected women and their children and other published studies. Meeting of EPHN clinical experts to reach a consensus on recommendations for management. Each recommendation was graded according to the level of evidence. RESULTS/CONCLUSIONS: Although several risk factors for mother-to-child transmission have been identified, none are modifiable and there are currently no interventions available to prevent vertical transmission of HCV. Data on timing of loss of maternal antibodies and reliability of diagnostic tests inform the optimum follow-up schedule for confirmation or exclusion of infection in children born to HCV infected women. Based on the current evidence, routine antenatal screening for HCV should not be introduced and neither elective caesarean section nor avoidance of breastfeeding should be recommended to HCV infected women to prevent mother-to-child transmission of HCV. HCV/HIV co-infected women should follow existing HIV guidelines.     

Serological Evidence of Widespread Zika Transmission across the Philippines

Zika virus (ZIKV) exposure across flavivirus-endemic countries, including the Philippines, remains largely unknown despite sporadic case reporting and environmental suitability for transmission. Using laboratory surveillance data from 2016, 997 serum samples were randomly selected from suspected dengue (DENV) case reports across the Philippines and assayed for serological markers of short-term (IgM) and long-term (IgG) ZIKV exposure. Using mixture models, we re-evaluated ZIKV IgM/G seroprevalence thresholds and used catalytic models to quantify the force of infection (attack rate, AR) from age-accumulated ZIKV exposure. While we observed extensive ZIKV/DENV IgG cross-reactivity, not all individuals with active DENV presented with elevated ZIKV IgG, and a proportion of dengue-negative cases (DENV IgG-) were ZIKV IgG-positive (14.3%, 9/63). We identified evidence of long-term, yet not short-term, ZIKV exposure across Philippine regions (ZIKV IgG+: 31.5%, 314/997) which was geographically uncorrelated with DENV exposure. In contrast to the DENV AR (12.7% (95%CI: 9.1–17.4%)), the ZIKV AR was lower (5.7% (95%CI: 3–11%)) across the country. Our results provide evidence of widespread ZIKV exposure across the Philippines and suggest the need for studies to identify ZIKV infection risk factors over time to better prepare for potential future outbreaks.     

Flavivirus cross‐reactivity in serological tests and Guillain‐Barré syndrome in a hematopoietic stem cell transplant patient: A case report

Serological diagnosis of flavivirus infection is a challenge, particularly in the context of a disease associated with immune response enhancement in a transplant patient, where aspects such as previous flavivirus infections may be involved with the outcome. We report a case of a pediatric patient who developed Guillain‐Barré syndrome (GBS) after matched‐unrelated hematopoietic stem cell transplantation (HSCT). The patient lives in a Brazilian region that is experiencing an epidemic of Zika virus (ZIKV) and dengue virus (DENV). Because an increasing number of cases of GBS, likely triggered by ZIKV infection, are being reported in Brazil, samples from the patient were tested for both ZIKV and DENV infection. Serological assays strongly suggested a recent ZIKV infection, although infection by DENV or co‐infection with both viruses cannot be ruled out. The presence of anti‐DENV immunoglobulin‐G in donor serum led to the hypothesis that antibodies from the donor could have enhanced the severity of the ZIKV infection. This hypothesis is in agreement with the recent findings that DENV sero‐cross‐reactivity drives antibody‐dependent enhancement of ZIKV infection. These findings highlight the need for discussion of the indication to perform previous flavivirus tests in HSCT donors, especially in areas where ZIKV and other flaviviruses co‐circulate.     

Breastfeeding and chronic HBV infection: clinical and social implications

Mother-to-child transmission of hepatitis B virus (HBV) is among the most important causes of chronic HBV infection and is the commonest mode of transmission worldwide. Currently, the presence of HBsAg, HBeAg and HBV DNA in breast milk is confirmed. Several studies have reported that breastfeeding carries no additional risk that might lead to vertical transmission. Beyond some limitations, the surveys have not demonstrated any differences in HBV transmission rate regarding feeding practices in early childho...