Search Results (48)

Background/Objectives: Classical swine fever (CSF) continues to challenge global eradication efforts, particularly in endemic regions, where pregnant sows face heightened risks of vertical transmission following exposure to CSFV. Methods: This study evaluates the early protective efficacy of FlagT4G, a novel live attenuated DIVA-compatible vaccine. Pregnant sows were vaccinated at mid-gestation and challenged 14 days later with a highly virulent CSFV strain. Results: FlagT4G conferred complete clinical protection, preventing both maternal viremia and transplacental transmission. No CSFV RNA, specific antibodies, or IFN-α were detected in fetal samples from vaccinated animals. In contrast, unvaccinated sows exhibited clinical signs, high viral loads, and widespread fetal infection. Interestingly, early protection was observed even in the absence of strong humoral responses in some vaccinated sows, suggesting a potential role for innate or T-cell-mediated immunity in conferring rapid protection. Conclusions: The demonstrated efficacy of FlagT4G within two weeks of vaccination underscores its feasibility for integration into emergency vaccination programs. Its DIVA compatibility and ability to induce early fetal protection against highly virulent CSFV strains position it as a promising tool for CSF control and eradication strategies. Full article

Background: Neonatal influenza is a rare condition. Young infants have immature immune defenses and are unable to receive direct vaccination; this can result in significant illness. Maternal anti-influenza immunization during pregnancy provides passive antibodies to the newborn via transplacental transfer, significantly decreasing the incidence and severity of influenza in early infancy. Nevertheless, the vaccination coverage during pregnancy remains low in many regions, leaving certain neonates without adequate protection. Methods: We present three cases of laboratory-confirmed influenza infection in neonates admitted to the “Sf. Ioan” Clinical Emergency Pediatric Hospital in Galați and conduct a literature review. The clinical presentation, co-infections, timing of antiviral therapy, laboratory findings, maternal vaccination status, and outcomes (including the hospitalization duration and recovery) were systematically analyzed for each case. Results: All three neonates were full-term and previously healthy, born to mothers who had not received influenza vaccinations during their pregnancies. They presented at ages ranging from 2 to 4 weeks with fever, respiratory symptoms including a cough, nasal congestion, and respiratory distress, as well as feeding difficulties. One case involved a co-infection with Bordetella pertussis, which manifested as a severe paroxysmal cough, cyanosis, and apnea. Laboratory findings in the cases with influenza alone indicated leukopenia accompanied by normal C-reactive protein levels. In the co-infection case, leukocytosis, lymphocytosis, and thrombocytosis were observed. All the infants received oseltamivir treatment within 48 h of the symptom onset; the case with pertussis co-infection also received azithromycin. Each infant required supplemental oxygen, but none necessitated mechanical ventilation. Clinical improvement was observed in all cases, with hospitalization ranging from 6 to 7 days and complete recovery without complications. Conclusions: Neonatal influenza may result in considerable morbidity, particularly in infants born to unvaccinated mothers. Positive outcomes, however, have been correlated with early diagnosis and antiviral treatment. Pertussis co-infection may exacerbate clinical progression, underscoring the importance of maternal immunization against both influenza and pertussis. In this case series, we aim to present three cases of laboratory-confirmed influenza in neonates born to mothers who were not immunized against influenza during pregnancy. These cases highlight the clinical presentations of neonatal influenza, underscore the risks associated with pertussis co-infection, and reinforce the importance of maternal influenza and Tdap vaccination for preventing severe outcomes in newborns. Full article

Porcine circovirus type 2 (PCV2) is a ubiquitous pathogen, and co-infections with the emerging PCV3 are increasingly reported. Both PCV2 and PCV3 have been implicated in reproductive failure, yet the diagnostic criteria for PCV3 remain under development. While fetal or neonatal antibody detection is a recognized indicator of transplacental infection in multiple species, PCV2 appears to be an exception due to the possible transfer of maternal antibodies. This study evaluated IgG, IgA, and IgM antibodies in the heart, kidney, lung, and spleen of aborted fetuses from sows co-infected with PCV2 and PCV3. PCR analysis revealed that all aborted fetuses were positive for both PCV2 and PCV3, with PCV3 Ct values being generally lower than those of PCV2, although this difference was not statistically significant. Antibody profiling showed a higher prevalence of anti-PCV3 IgM and IgA compared to anti-PCV2 IgM and IgA, particularly in the heart, kidney, and lung, while IgG responses against both viruses were similar. These findings suggest that the detection of anti-PCV3 antibodies in fetal tissues may provide supportive evidence of PCV2 and PCV3 infection and the possible involvement of these viruses in reproductive failure; however, further studies are needed to establish causation definitively. Full article

Background/Objectives: Respiratory syncytial virus (RSV) is the leading cause of severe respiratory disease in infants worldwide. Maternal immunization to protect younger infants is supported by evidence that virus-neutralizing antibodies, which are efficiently transferred across the placenta from mother to fetus, are a primary immune mediator of protection. In maternal RSV vaccine studies, estimates of correlates of protection are elusive because many factors of maternal–fetal immunobiology and disease characteristics must be considered for the estimates. Methods: We developed statistical models that aims to predict vaccine efficacy (VE) in infants following maternal immunization by including quantifiable covariates of the antibody titer distribution of the mother (pre- and post-immunization), the transplacental transfer ratio of IgG antibodies, the rate of antibody decay, and RSV disease incidence rate, all of which are season- and time-dependent and vary by infant age. Result: Our model shows that integrating the lower respiratory tract disease risk based on infant airway diameter and associated airway resistance is critical to appropriately model predicted infant VE. The VE predictions by our models, which preceded maternal RSV prefusion F vaccine efficacy trial primary readouts, closely align with the VE outcomes of these field studies. Conclusion: Our models successfully predicted VE of the RSV maternal vaccines and have potential use in modeling the clinical trial out-comes of other respiratory disease vaccines where maternal antibodies play a role in the protection of newborns. Full article

Background: There is limited evidence comparing hepatitis A seroprevalence among HIV-exposed uninfected (HEU), HIV-infected (HIV), and unexposed uninfected (HUU) children. This compromises rational vaccine decision-making. Methods: This study comprised a retrospective health facility-based population of children aged 1 month–12 years. Archival sera were tested for markers of acute (anti-HAV IgM) or past (total anti-HAV) HAV infection. Subgroup analysis was conducted based on perinatal HIV exposure or infection status. Results: Among 513 children, the median age was 10 (IQR: 4–25) months. The median maternal age was 29 (IQR: 25–34) years. An anti-HAV seropositivity of 95.1% (117/122 [95% CI 90.2–98.4]) was found among those ≤6 months of age, indicative of the rate of transplacental antibody transfer. Among 1–12-year-olds, hepatitis A seroprevalence was 19.3% (37/192 [95% CI 14.1–25.7]), while 1.1% (2/188 [95% CI 0.12–2.76]) had evidence of acute infection. Compared to HIV-exposed subgroups (HIV = 60%, 6/10 [95% CI 27.4–86.3] and HEU = 45%, 9/20 [95% CI 23.8–68]), hepatitis A seroprevalence among HUU children was low (29.2%, 47/161 [95% CI 22.4–37.0]). Conclusions: Natural immunity among HIV-exposed and unexposed children in South Africa is insufficient to protect against severe liver complications associated with HAV infection later in adulthood. Full article

Vaccination in pregnancy is important to protect the mother and fetus from infectious diseases. The transfer of maternal antibodies across the placenta during pregnancy can continue to protect the neonate for several months after birth while the neonatal adaptive immune system develops. Several pathogens have been shown to impair the transplacental transfer of maternal antibodies, including human immunodeficiency virus, malaria, the severe acute respiratory syndrome coronavirus 2, and cytomegalovirus. This review discusses the mechanisms contributing to decreased transplacental antibody transfer in the setting of maternal infections, such as changes in antibody glycosylation profile, maternal hypergammaglobulinemia, and placental injury. The frequency of epidemics is increasing, and pregnant people are more likely to become exposed to novel pathogens now than they were in the past. Understanding the mechanisms by which infectious diseases impair maternal–fetal antibody transfer is important for pandemic preparedness to maximize the impact of maternal vaccination for child health. Full article

Background and aims: The transplacental vertical transfer of maternal antibodies was determined to be a crucial factor in conferring protective immunity to infants following delivery, and this study aimed to evaluate the protective effect of maternal preconception COVID-19 vaccination on infants. Methods: A prospective cohort study was conducted at the National Clinical Medical Research Center for Child Health and Diseases in Chongqing, China, spanning from July 2022 to April 2023. The study included infants from mothers with a preconception COVID-19 vaccination and (or) a SARS-CoV-2 infection during pregnancy. Titers of SARS-CoV-2 immunoglobulin G (IgG) and cross-neutralizing activity against SARS-CoV-2 variants were detected. Results: In this cohort study comprising 158 infants, it was observed that infants born to mothers who experienced a pregnancy-related breakthrough infection following a preconception vaccination had the highest titers of SARS-CoV-2 IgG and cross-neutralizing antibody activity against different variants compared to those with either of these factors alone. The transplacental vertical transmission of anti-SARS-CoV-2 antibodies decreased significantly with increasing age, from 3.16 ODs at birth to 2.29 ODs at two months, and persisted for approximately four months after birth. The predominant subclass of passively transmitted antibodies via the placenta was found to be IgG1, and a positive correlation was observed between the titers of SARS-CoV-2 IgG and IgG1 (R = 0.59, p < 0.001; Slope: 0.49 ± 0.070, p < 0.001). Conclusions: Maternal preconception COVID-19 vaccination represents a promising immunological strategy for conferring postnatal protection to infants, especially during the period of heightened risk of exposure to SARS-CoV-2 infection. It is imperative to underscore the significance of vaccination for women who are preparing to become pregnant or are pregnant, and concerted efforts must be made to promote vaccination among eligible women. Full article

In the last twelve months, a significant global increase in pertussis cases has been observed, particularly among infants under three months of age. This age group is at the highest risk for severe disease, hospitalization, and death. Maternal immunization with the Tdap vaccine during pregnancy has been recommended to protect newborns by transferring maternal antibodies transplacentally. This review examines the current epidemiology of pertussis, the importance of preventing it in young children, and the effectiveness of maternal immunization. Despite the proven benefits of maternal vaccination, which has been found effective in pertussis prevention in up to 90% of cases, coverage remains suboptimal in many countries. Factors contributing to low vaccination rates include vaccine hesitancy due to low trust in health authority assessments, safety concerns, practical barriers to vaccine access, and the impact of the COVID-19 pandemic, which disrupted routine vaccination services. The recent increase in pertussis cases may also be influenced by the natural cyclic nature of the disease, increased Bordetella pertussis (Bp) activity in older children and adults, and the genetic divergence of circulating Bp strains from vaccine antigens. Given the high efficacy of maternal vaccination in preventing pertussis in infants, increasing coverage rates is crucial. Efforts to improve vaccine uptake should address barriers to access and vaccine hesitancy, ensuring consistent immune protection for the youngest and most vulnerable populations. Enhanced maternal vaccination could significantly reduce the incidence of whooping cough in infants, decreasing related hospitalizations and deaths. Full article

Background: The objective of this study is to analyze the transplacental transmission of SARS-CoV-2 antibodies, their persistence in newborns, the factors that may influence this transmission, and the protection these antibodies confer over time. Methods: This prospective cohort was conducted in a tertiary pediatric hospital in the Barcelona Metropolitan Region, Spain. It included neonates born to mothers who had SARS-CoV-2 infection during pregnancy or delivery between August 2020 and January 2022. We followed the recruited children for at least six months, and blood tests were performed to determine the presence of SARS-CoV-2 antibodies. Results: A total of 101 children were recruited. Among the serologies performed on children under three months of age, 44/82 were positive (53.7%). Newborns whose mothers presented more severe disease exhibited higher seropositivity odds (coefficient 9.747; p = 0.002). There were increased preterm deliveries when maternal infection occurred closer to the time of delivery. No severe SARS-CoV-2 infections were detected in children during the follow-up. Conclusions: Slightly more than half of the SARS-CoV-2 serologies performed in the first three months were positive. This appears to confer protection during early childhood. The severity of maternal infection is the most significant factor influencing the transmission of antibodies in children born to unvaccinated mothers. Full article

The Macavirus genus, Gammaherpesvirinae subfamily, Herpesviridae family, contains ovine gammaherpesvirus 2 (OvGHV2), the cause of sheep-associated malignant catarrhal fever (SA-MCF). Members of the Macavirus genus associated with the development of malignant catarrhal fever (MCF) in their respective hosts share the 15A antigenic epitope, are conserved within the DNA polymerase gene and are collectively referred to as the malignant catarrhal fever virus (MCFV) complex. The ability of MCFV and/or OvGHV2 to produce abortions in ruminants is currently unknown, with little documentation of infections by these agents in bovine fetuses. This report presents the findings observed due to the detection of OvGHV2 DNA and MCFV tissue antigens in aborted bovine fetuses from southern Brazil. Four aborted bovine fetuses from three farms, located in a geographical region of Paraná State with elevated immunohistochemical (IHC) prevalence of MCFV tissue antigens, with gestational ages varying between 78 to 208 days were investigated. Significant gross and histopathological alterations were not observed in any of these fetuses. An IHC assay using the 15A-monoclonal antibody (15A-MAb), which is based on the 15A antigenic epitope of Macavirus, identified MCFV tissue antigens in multiple organs from two fetuses (#1 and #4); however, positive immunoreactivity to the 15A-MAb IHC assay was not detected in Fetus #2 and #3. Molecular testing amplified OvGHV2 DNA only from the myocardium and lungs of Fetus #1 that had positive intracytoplasmic immunoreactivity to the 15A-MAb IHC assay in these tissues. Furthermore, infections by Leptospira spp. were confirmed by molecular assays in fetuses #1, #3, and #4, while PCR detected Neospora caninum in the myocardium of Fetus #2. Additionally, molecular assays to identify well-known fetopathy agents of cattle, including bovine viral diarrhea virus, bovine alphaherpesvirus 1, Histophilus somni, and Listeria monocytogenes, did not amplify the nucleic acids of these pathogens. PCR assays to identify bovine gammaherpesvirus 6 (BoGHV6), another Macavirus known to infect cattle in Brazil, were unsuccessful. These findings confirmed that the 15A-MAb IHC assay can be efficiently used to detect MCFV antigens in organs of aborted bovine fetuses. The identification of MCFV antigens with the simultaneous detection of OvGHV2 DNA confirmed that Fetus #1 was infected by OvGHV2 and added to the few descriptions of this infection in aborted fetuses of ruminants worldwide. Moreover, the IHC detection of MCFV in multiple organs of Fetus #4, without the molecular detection of OvGHV2 or BoGHV6, may suggest that this fetus was infected by a Macavirus that was not previously diagnosed in cattle herds from Brazil. These findings strongly suggest that OvGHV2 and MCFV can produce transplacental infections in cattle. Full article

In the present study, we evaluated the influence of maternal and neonatal factors on the efficiency of the placental transfer of neutralizing antibodies against SARS-CoV-2. Vaccination during pregnancy provides fetal and neonatal protection through the passive transplacental transfer of maternal neutralizing antibodies. To date, little information is available regarding the factors that affect the transfer of antibodies against SARS-CoV-2. A retrospective, cross-sectional, observational, and analytical study was carried out. It was found that several biological factors could be altering transplacental passive immunity after vaccination against COVID-19. In our study population, type 2 diabetes mellitus and chronic hypertension tended to decrease efficiency, while data from women with pre-eclampsia showed better indices compared to those from women with healthy pregnancies. Neonates born prematurely showed lower transfer rates when compared to healthy neonates. The premature rupture of membranes significantly decreased antibody transfer. Taken together, the data suggest that vaccination against COVID-19 during pregnancy is effective even under certain unfavorable clinical conditions for the mother, fetus, and neonate. It is important to create and disseminate immunization strategies in vulnerable populations to reduce maternal and perinatal morbidity and mortality associated with infections preventable by vaccination. Full article

The transplacental transmission of CSFV and the resulting persistent congenital infection in newborn piglets have been abundantly discussed in pregnant sows suffering from virus infection. Importantly, the availability of safe commercial vaccines with proven efficacy to prevent the generation of congenital and postnatal persistent infections in pregnant sows are critical tools for controlling the disease in CSF endemic areas. Here, we demonstrate the high efficacy of a single dose of the recombinant FlagT4G vaccine to provide solid protection in pregnant sows against transplacental transmission of a highly virulent CSFV. Pregnant sows vaccinated with FlagT4G at 44 days of gestation elicited a strong CSFV-specific antibody response, with neutralizing antibody levels above those required for protection against CSFV. Importantly, after the challenge with a highly virulent CSFV, all foetuses from FlagT4G-vaccinated sows lacked CSF macroscopic lesions and showed a complete absence of the challenge virus in their internal organs at day 79 of gestation. Therefore, pregnant sows safely vaccinated with FlagT4G without affecting reproductive efficacy are efficaciously protected, along with their foetuses, against the infection and disease caused by a CSFV virulent field strain. Full article

Leptospirosis is an infectious disease that affects domestic animals, wild animals, and humans. It represents a public health problem and has an important economic impact on livestock. This study aims to investigate the importance of genital and transplacental infection in the epidemiology of leptospirosis in cows maintained in Caatinga biome conditions, Northeastern Brazil, as well as reporting organs colonized by Leptospira spp. in embryos and fetuses. Blood, urinary tract (urine, bladder, and kidney), and reproductive tract (vaginal fluid, uterus, uterine tube, ovary, and placenta) samples were collected from 15 slaughtered pregnant cows. Two embryos and 13 fetuses were sampled. Central nervous system and choroid ovoid samples were collected from embryos. Blood, central nervous system, lung, peritoneal liquid, abomasal content, liver, spleen, urine, bladder, kidney, and reproductive system samples were collected from fetuses. Diagnostic methods included the microscopic agglutination test (MAT) using a collection of 24 serovars belonging to 17 different pathogenic serogroups of five species as antigens, as well as polymerase chain reaction (PCR). Anti-Leptospira spp. antibodies were found in 9 cows (60%), while 13 cows (86.67%) had at least one organ or urine with leptospiral DNA. No fetus was seroreactive. Among the embryos and fetuses, 13 (86.67%) presented leptospiral DNA, proving a high frequency of transplacental infection (100%). For cows, the most frequent biological materials regarding Leptospira spp. DNA detection were placenta (13 out of 15 samples; 86.7%), uterus (10 out of 15 samples; 66.7%), and vaginal fluid (5 out of 15 samples; 33.3%), while, for fetuses/embryos, the most frequent PCR-positive samples were choroid ovoid (1/2; 50%), spleen (6/13; 46.2%), kidney (5/13; 38.5%), and central nervous system (5/15; 33.3%). Sequenced samples based on the LipL32 gene presented 99% similarity with L. borgpetersenii. The results indicate that transplacental infection is an efficient way of spreading Leptospira spp. in cows maintained in Caatinga biome conditions. Therefore, prevention and control strategies must include actions that interrupt transmission through this alternative route. Full article

A pregnancy booster dose significantly reduces the risk and severity of COVID-19, and it is widely recommended. A prospective cohort study was conducted to compare the transplacental passage of maternal antibodies from vaccination or infection during three trimesters against both the vaccine-targeted Wuhan strain and the Omicron strain of SARS-CoV-2. Maternal–infant dyads from vaccinated mothers were collected between 6 June 2022 and 20 September 2022. We analyzed 38 maternal–infant dyads from mothers who had been infected with COVID-19 and 37 from mothers without any previous infection. Pregnant women who received their last COVID-19 vaccine dose in the third trimester exhibited the highest anti-spike protein antibody levels and neutralizing potency against both the Wuhan strain and Omicron BA.2 variant in their maternal and cord plasma. Both second- and third-trimester vaccination could lead to a higher level of neutralization against the Wuhan and Omicron strains. COVID-19 infection had a negative effect on the transplacental transfer ratio of SARS-CoV-2 antibodies. A booster dose during the second or third trimester is encouraged for the maximum transplacental transfer of humoral protection against COVID-19 for infants. Full article

Parvovirus B19, a member of the Parvoviridae family, is a human pathogenic virus. It can be transmitted by respiratory secretions, hand-to-mouth contact, blood transfusion, or transplacental transmission. Most patients are asymptomatic or present with mild symptoms such as erythema infectiosum, especially in children. In rare cases, moderate-to-severe symptoms may occur, affecting blood cells and other systems, resulting in anemia, thrombocytopenia, and neutropenia. Non-immune pregnant women are at risk for fetal infection by parvovirus B19, with greater complications if transmission occurs in the first or second trimester. Infected fetuses may not show any abnormalities in most cases, but in more severe cases, there may be severe fetal anemia, hydrops, and even pregnancy loss. Maternal diagnosis of intrauterine parvovirus B19 infection includes IgG and IgM antibody testing. For fetal diagnosis, PCR is performed through amniocentesis. In addition to diagnosing the infection, it is important to monitor the peak of systolic velocity of the middle cerebral artery (PVS-MCA) Doppler to assess the presence of fetal anemia. There is no vaccine for parvovirus B19, and fetal management focuses on detecting moderate/severe anemia by fetal PVS-MCA Doppler, which, if diagnosed, should be treated with intrauterine transfusion by cordocentesis. Prevention focuses on reducing exposure in high-risk populations, particularly pregnant women. Full article