Background: Although there is evidence of person-to-person transmission of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in household and healthcare settings, more data are needed to describe and better understand the risk factors and transmission routes in both settings, as well as the extent that disease severity affects transmission. Methods: A sero-epidemiological investigation was conducted among Middle East Respiratory Syndrome Coronavirus (MERS-CoV) case-patients and their household contacts to investigate transmission risk in Abu Dhabi, United Arab Emirates. Cases diagnosed between January 1, 2013-May 9, 2014 and their household contacts were approached for enrollment. Demographic, clinical, and exposure history data were collected. Sera were screened by MERS-CoV nucleocapsid protein (N) ELISA and indirect immunofluorescence, with results confirmed by microneutralization assay. Results: Ninety-one percent (n=31/34) of case-patients were asymptomatic or mildly symptomatic and did not require oxygen during hospitalization. MERS-CoV antibodies were detected in 13 of 24 (54%) cases with available sera, including 3 asymptomatic, 9 mildly symptomatic, and 1 severely symptomatic case-patient. No serologic evidence of MERS-CoV transmission was found among 105 household contacts with available sera. Conclusions: Transmission of MERS-CoV was not documented in this investigation of mostly asymptomatic and mildly symptomatic cases and their household contacts. These results have implications for clinical management of cases and formulation of isolation policies to reduce the risk of transmission.

Middle East respiratory syndrome coronavirus, MERS-CoV, was identified in Saudi Arabia in 2012, and as of January 29, 2018, there were 2,123 laboratory-confirmed MERS-CoV cases reported to WHO (WHO, 2018, https://www.who.int/emergencies/mers-cov/en/). Multiple studies suggest that dromedary camels are a source for human MERS-CoV infection. MERS-CoV-specific antibodies have been detected in the serum of dromedary camels across Northern Africa and across the Arabian Peninsula. Israel's geographic location places Israel at risk for MERS-CoV infection. To date, MERS-CoV-related illness has not been reported and the burden of MERS-CoV infection in the Israeli population is unknown. The seroprevalence of MERS-CoV-specific antibodies in Israeli dromedary camels is unknown. The objective of this study was to determine the prevalence of MERS-CoV seropositivity in dromedary camels in Israel. The prevalence of MERS-CoV antibodies in Israeli camels was examined in 71 camel sera collected from four farms across Israel by MERS-CoV-specific microneutralization (Mnt) assay and confirmed by MERS-CoV-specific immunofluorescence assay (IFA). Although this study cannot rule out potential antibody cross-reactivity by IFA, the presence of bovine coronavirus-specific antibodies do not appear to impact detection of MERS-CoV antibodies by Mnt. MERS-CoV neutralizing antibodies were detectable in 51 (71.8%) camel sera, and no association was observed between the presence of neutralizing antibodies and camel age or gender. These findings extend the known range of MERS-CoV circulation in Middle Eastern camels. The high rate of MERS-CoV-specific antibody seropositivity in dromedary camels in the absence of any reported human MERS cases suggests that there is still much to be learned about the dynamics of camel-to-human transmission of MERS-CoV.

RSV continues to be a high priority for vaccine and antiviral drug development. Unfortunately, no safe and effective RSV vaccine is available and treatment options are limited. Over the past decade, several studies have focused on the role of RSV G protein on viral entry, viral neutralization, and RSV-mediated pathology. Anti-G murine monoclonal antibody (mAb) 131-2G treatment has been previously shown to reduce weight loss, bronchoalveolar lavage (BAL) cell number, airway reactivity, and Th2-type cytokine production in RSV-infected mice more rapidly than a commercial humanized monoclonal antibody (mAb) against RSV F protein (Palivizumab). In this study, we have tested two human anti-RSV G mAbs, 2B11 and 3D3, by both prophylactic and therapeutic treatment for RSV in the BALB/c mouse model. Both anti-G mAbs reduced viral load, leukocyte infiltration and IFN-gamma and IL-4 expression in cell-free BAL supernatants emphasizing the potential of anti-G mAbs as anti-inflammatory and antiviral strategies.

Middle East Respiratory Syndrome coronavirus (MERS-CoV) causes a highly lethal pulmonary infection with approximately 35% mortality. The potential for a future pandemic originating from animal reservoirs or healthcare-associated events is a major public health concern. There are no vaccines or therapeutic agents currently available for MERS-CoV. Using a probe-based single B cell-cloning strategy, we have identified and characterized multiple neutralizing mAbs specifically binding to the receptor binding domain (RBD) or S1 (non-RBD) regions from a convalescent MERS-CoV-infected patient and from immunized rhesus macaques. RBD-specific mAbs tended to have greater neutralizing potency than non-RBD S1-specific mAbs. Six RBD-specific and five S1-specific mAbs could be sorted into four RBD and three non-RBD distinct binding patterns, based on competition assays, mapping neutralization escape variants, and structural analysis. We determined co-crystal structures for two mAbs targeting RBD from different angles and show they can only bind RBD in the "out" position. We then showed that selected RBD-specific, non-RBD S1, and S2-specific mAbs given prophylactically prevented MERS-CoV replication in lungs and protected mice from lethal challenge. Importantly, combining RBD- and non-RBD mAbs delayed the emergence of escape mutations in a cell-based virus-escape assay. These studies identify mAbs targeting different antigenic sites on S that will be useful for defining mechanisms of MERS-CoV neutralization, and for developing more effective interventions to prevent or treat MERS-CoV infections.IMPORTANCE: MERS-CoV causes a highly lethal respiratory infection for which no vaccines or antiviral therapeutic options are currently available. Based on continuing exposure from established reservoirs in dromedary camels and bats, transmission of MERS-CoV into humans and future outbreaks are expected. Using structurally-defined probes for the MERS-CoV Spike (S) glycoprotein, the target for neutralizing antibodies, single B cells were sorted from a convalescent human and immunized non-human primates (NHPs). mAbs produced from paired immunoglobulin gene sequences were mapped to multiple epitopes within and outside the receptor-binding domain (RBD) and protected against lethal MERS infection in a murine model following passive immunization. Importantly, combining mAbs targeting distinct epitopes prevented viral neutralization escape from RBD-directed mAbs. These data suggest that antibody responses to multiple domains on CoV Spike may improve immunity and will guide future vaccine and therapeutic development efforts.

The Second Year of Life project of the Global Health Security Agenda aims to improve immunization systems and strengthen measles and rubella surveillance, including building laboratory capacity. A new laboratory assessment tool was developed by the Centers for Disease Control and Prevention to assess the national laboratory in Ghana to improve molecular surveillance for measles and rubella. Results for the tool showed that the laboratory is well organized, has a good capacity for handling specimens, has a good biosafety system, and is proficient for diagnosis of measles and rubella by serologic analysis. However, there was little knowledge about molecular biology and virology activities (i.e., virus isolation on tissue culture was not available). Recommendations included training of technical personnel for molecular techniques and advocacy for funding for laboratory equipment, reagents, and supplies.

Respiratory Syncytial Virus (RSV) infects respiratory epithelial cells and deregulates host gene expression by many mechanisms including expression of RSV G protein (RSV G). RSV G protein encodes a central conserved region (CCR) containing a CX3C motif that functions as a fractalkine mimic. Disruption of the CX3C motif (a.a. 182-186) located in the CCR of the G protein has been shown to affect G protein function in vitro and the severity of RSV disease pathogenesis in vivo. We show that infection of polarized Calu3 respiratory cells with recombinant RSV having point mutations in Cys173 and 176 (C173/176S) (rA2-GC12), or Cys186 (C186S) (rA2-GC4) is associated with a decline in the integrity of polarized Calu-3 cultures and decreased virus production. This is accompanied with downregulation of miRNAs let-7f and miR-24 and upregulation of interferon lambda (IFNlambda), a primary antiviral cytokine for RSV in rA2-GC12/rA2-GC4 infected cells. These results suggest that residues in the cysteine noose region of RSV G protein can modulate IFN lambda expression accompanied by downregulation of miRNAs, and are important for RSV G protein function and targeting.

Respiratory syncytial virus (RSV) belongs to the family Paramyxoviridae and is the single most important cause of serious lower respiratory tract infections in young children, yet no highly effective treatment or vaccine is available. Through a CX3C chemokine motif (182CWAIC186) in the G protein, RSV binds to the corresponding chemokine receptor, CX3CR1. Since RSV binding to CX3CR1 contributes to disease pathogenesis, we investigated whether a mutation in the CX3C motif by insertion of an alanine A186 within the CX3C motif to CX4C (182CWAIAC187), known to block binding to CX3CR1, might decrease disease. We studied the effect of the CX4C mutation in two strains of RSV (A2 and r19F) in a mouse challenge model. We included the RSV r19F because it induces mucous production and airway resistance, two manifestations of RSV infection in humans, in mice. Compared to wildtype virus (wt), mice infected with the CX4C had a 0.7 to 1.2 log10-fold lower virus titer in the lung at 5 days p.i. and had markedly reduced weight loss, pulmonary inflammatory cell infiltration, mucous production, and airway resistance after challenge. This decrease in disease was not dependent on decrease in virus replication but did correspond to a decrease in pulmonary Th2 and inflammatory cytokines. Mice infected with CX4C viruses also had higher antibody titers and a Th1 biased T cell memory response at 75 days pi. These results suggest that the CX4C mutation in the G protein could improve the safety and efficacy of a live attenuated RSV vaccine.Importance RSV binds to the corresponding chemokine receptor, CX3CR1, through a CX3C chemokine motif (182CWAIC186) in the G protein. RSV binding to CX3CR1 contributes to disease pathogenesis, therefore, we investigated whether a mutation in the CX3C motif by insertion of an alanine A186 within the CX3C motif to CX4C (182CWAIAC187), known to block binding to CX3CR1, might decrease disease. The effect of this mutation and treatment with the F(ab')2 form of the anti-RSV G 131-2G mAb show that mutating the CX3C motif to CX4C blocks much of the disease and immune modulation associated with the G protein and should improve the safety and efficacy of a live attenuated RSV vaccine.

To determine how long antibodies against Middle East respiratory syndrome coronavirus persist, we measured long-term antibody responses among persons serologically positive or indeterminate after a 2012 outbreak in Jordan. Antibodies, including neutralizing antibodies, were detectable in 6 (86%) of 7 persons for at least 34 months after the outbreak.

Defective interfering viral particles have been reported as important determinants of the course of viral infection, and they can markedly temper the virulence of the infection. Here, we describe a simple method, based on limiting dilution, for the removal of defective interfering particles from RSV. This method results in a high-titer viral preparation from both HEp-2 and Vero cell lines. We evaluated two concentrations of sucrose to stabilize the virus preparation, and demonstrate that RSV is stable when prepared and stored in 25 % sucrose at -152 degrees C. In addition, this chapter describes some commonly used methods of RSV titration, detection using microtitration and quantitative real-time RT-PCR, and the use of immunostaining for antigenic characterization.

Risk factors for human-to-human transmission of Middle East respiratory syndrome coronavirus (MERS-CoV) are largely unknown. After MERS-CoV infections occurred in an extended family in Saudi Arabia in 2014, relatives were tested by using real-time reverse transcription PCR (rRT-PCR) and serologic methods. Among 79 relatives, 19 (24%) were MERS-CoV positive; 11 were hospitalized, and 2 died. Eleven (58%) tested positive by rRT-PCR; 8 (42%) tested negative by rRT-PCR but positive by serology. Compared with MERS-CoV-negative adult relatives, MERS-CoV-positive adult relatives were older and more likely to be male and to have chronic medical conditions. Risk factors for household transmission included sleeping in an index patient's room and touching respiratory secretions from an index patient. Casual contact and simple proximity were not associated with transmission. Serology was more sensitive than standard rRT-PCR for identifying infected relatives, highlighting the value of including serology in future investigations.

In January 2013, several months after Middle East respiratory syndrome coronavirus (MERS-CoV) was first identified in Saudi Arabia, Abu Dhabi, United Arab Emirates, began surveillance for MERS-CoV. We analyzed medical chart and laboratory data collected by the Health Authority-Abu Dhabi during January 2013-May 2014. Using real-time reverse transcription PCR, we tested respiratory tract samples for MERS-CoV and identified 65 case-patients. Of these patients, 23 (35%) were asymptomatic at the time of testing, and 4 (6%) showed positive test results for >3 weeks (1 had severe symptoms and 3 had mild symptoms). We also identified 6 clusters of MERS-CoV cases. This report highlights the potential for virus shedding by mildly ill and asymptomatic case-patients. These findings will be useful for MERS-CoV management and infection prevention strategies.

Middle East respiratory syndrome coronavirus (MERS-CoV) infections sharply increased in the Arabian Peninsula during spring 2014. In Abu Dhabi, United Arab Emirates, these infections occurred primarily among healthcare workers and patients. To identify and describe epidemiologic and clinical characteristics of persons with healthcare-associated infection, we reviewed laboratory-confirmed MERS-CoV cases reported to the Health Authority of Abu Dhabi during January 1, 2013-May 9, 2014. Of 65 case-patients identified with MERS-CoV infection, 27 (42%) had healthcare-associated cases. Epidemiologic and genetic sequencing findings suggest that 3 healthcare clusters of MERS-CoV infection occurred, including 1 that resulted in 20 infected persons in 1 hospital. MERS-CoV in healthcare settings spread predominantly before MERS-CoV infection was diagnosed, underscoring the importance of increasing awareness and infection control measures at first points of entry to healthcare facilities.

Middle East respiratory syndrome coronavirus (MERS-CoV) infection causes an acute respiratory illness and is associated with a high case fatality rate; however, the pathogenesis of severe and fatal MERS-CoV infection is unknown. We describe the histopathologic, immunohistochemical, and ultrastructural findings from the first autopsy performed on a fatal case of MERS-CoV in the world, which was related to a hospital outbreak in the United Arab Emirates in April 2014. The main histopathologic finding in the lungs was diffuse alveolar damage. Evidence of chronic disease, including severe peripheral vascular disease, patchy cardiac fibrosis, and hepatic steatosis, was noted in the other organs. Double staining immunoassays that used anti-MERS-CoV antibodies paired with immunohistochemistry for cytokeratin and surfactant identified pneumocytes and epithelial syncytial cells as important targets of MERS-CoV antigen; double immunostaining with dipeptidyl peptidase 4 showed colocalization in scattered pneumocytes and syncytial cells. No evidence of extrapulmonary MERS-CoV antigens were detected, including the kidney. These results provide critical insights into the pathogenesis of MERS-CoV in humans.

BACKGROUND: Respiratory syncytial virus (RSV) is a major cause of severe lower respiratory tract illness in young children worldwide. Treatment options for severe RSV disease remain limited and the development of therapeutic treatment strategies remains a priority. LL-37, a small cationic host defense peptide involved in anti-inflammatory and anti-bacterial responses, reduces replication of or infection by multiple viruses, including influenza virus, in vitro, and protects against lethal challenge with influenza virus in vivo. LL-37 also protects against RSV infection of HEp-2 cells in vitro; however, HEp-2 are not reflective of polarized airway epithelial cells and respond differently to RSV infection. An air-liquid interface (ALI) Calu-3 model that more closely mimics the human airway epithelium was established. Using this in vitro model, the effectiveness of LL-37 in preventing RSV infection and replication was examined. RESULTS: LL-37, when pre-incubated with virus prior to RSV infection (prophylactic), significantly reduced the level of viral genome detected in infected Calu-3 cells, and decreased chemokine expression associated with RSV infection in vitro. In contrast, therapeutic treatment of RSV-infected ALI Calu-3 at 24 h and 3 days post-infection had minimal impact on RSV infection. CONCLUSIONS: Differences in the efficacy of LL-37 at reducing RSV infection under prophylactic and therapeutic conditions may in part be ascribed to differences in the method of peptide exposure. However, the efficacy of LL-37 at reducing RSV infection under prophylactic conditions indicates that further studies examining the efficacy of LL-37 as a small peptide inhibitor of RSV are warranted.

In May 2014, a traveler from the Kingdom of Saudi Arabia was the first person identified with Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the United States. To evaluate transmission risk, we determined the type, duration, and frequency of patient contact among health care personnel (HCP), household, and community contacts by using standard questionnaires and, for HCP, global positioning system (GPS) tracer tag logs. Respiratory and serum samples from all contacts were tested for MERS-CoV. Of 61 identified contacts, 56 were interviewed. HCP exposures occurred most frequently in the emergency department (69%) and among nurses (47%); some HCP had contact with respiratory secretions. Household and community contacts had brief contact (e.g., hugging). All laboratory test results were negative for MERS-CoV. This contact investigation found no secondary cases, despite case-patient contact by 61 persons, and provides useful information about MERS-CoV transmission risk. Compared with GPS tracer tag recordings, self-reported contact may not be as accurate.

Respiratory syncytial virus (RSV) belongs to the family Paramyxoviridae and is the single most important cause of serious lower respiratory tract infections in young children, yet no highly effective treatment or vaccine is available. To clarify the potential for an anti-G mAb, 131-2G which has both anti-viral and anti-inflammatory effects, to effectively treat RSV disease, we determined the kinetics of its effect compared to the effect of the anti-F mAb, 143-6C on disease in mice. Treatment administered three days after RSV rA2-line19F (r19F) infection showed 131-2G decreased breathing effort, pulmonary mucin levels, weight loss, and pulmonary inflammation earlier and more effectively than treatment with mAb 143-6C. Both mAbs stopped lung virus replication at day 5 post-infection. These data show that, in mice, anti-G protein mAb is superior to treating disease during RSV infection than an anti-F protein mAb similar to Palivizumab. This combination of anti-viral and anti-inflammatory activity makes 131-2G a promising candidate for treating for active human RSV infection.

BACKGROUND: Incidence estimates of hospitalizations for community-acquired pneumonia among children in the United States that are based on prospective data collection are limited. Updated estimates of pneumonia that has been confirmed radiographically and with the use of current laboratory diagnostic tests are needed. METHODS: We conducted active population-based surveillance for community-acquired pneumonia requiring hospitalization among children younger than 18 years of age in three hospitals in Memphis, Nashville, and Salt Lake City. We excluded children with recent hospitalization or severe immunosuppression. Blood and respiratory specimens were systematically collected for pathogen detection with the use of multiple methods. Chest radiographs were reviewed independently by study radiologists. RESULTS: From January 2010 through June 2012, we enrolled 2638 of 3803 eligible children (69%), 2358 of whom (89%) had radiographic evidence of pneumonia. The median age of the children was 2 years (interquartile range, 1 to 6); 497 of 2358 children (21%) required intensive care, and 3 (<1%) died. Among 2222 children with radiographic evidence of pneumonia and with specimens available for bacterial and viral testing, a viral or bacterial pathogen was detected in 1802 (81%), one or more viruses in 1472 (66%), bacteria in 175 (8%), and both bacterial and viral pathogens in 155 (7%). The annual incidence of pneumonia was 15.7 cases per 10,000 children (95% confidence interval [CI], 14.9 to 16.5), with the highest rate among children younger than 2 years of age (62.2 cases per 10,000 children; 95% CI, 57.6 to 67.1). Respiratory syncytial virus was more common among children younger than 5 years of age than among older children (37% vs. 8%), as were adenovirus (15% vs. 3%) and human metapneumovirus (15% vs. 8%). Mycoplasma pneumoniae was more common among children 5 years of age or older than among younger children (19% vs. 3%). CONCLUSIONS: The burden of hospitalization for children with community-acquired pneumonia was highest among the very young, with respiratory viruses the most commonly detected causes of pneumonia. (Funded by the Influenza Division of the National Center for Immunization and Respiratory Diseases.).

Respiratory syncytial virus (RSV) is the single most important cause of serious lower respiratory tract infections in young children, yet no highly effective treatment or vaccine is available. In the present study, we investigated the effect of prophylactic treatment with the intact and F(ab')2 forms of an anti-G protein monoclonal antibody (mAb), 131-2G, on the humoral and cellular adaptive immune response to RSV rA2-line19F (r19F) challenge in BALB/c mice. The F(ab')2 form of 131-2G does not decrease virus replication but intact 131-2G does. The serum specimens for antibodies and spleen cells for memory T cell responses to RSV antigens were analyzed at 30, 45, 75 and 95 p.i. with/without prior treatment with 131-2G. The ratios of Th2/Th1 antibody isotypes at each time p.i indicated that both forms of mAb 131-2G shifted the subclass response from a Th2 (IgG1 and IgG2b) to a Th1 (IgG2A) bias. The ratio of IgG1/IgG2A antibody titer was 3-fold to 10-fold higher for untreated than mAb treated mice. There was also some increase in IgG (22%+/-13 increase) and neutralization (32% increase) in antibodies with mAb 131-2G prophylaxis at 75 days p.i. Treatment with 131-2G significantly (p≤0.001) decreased the percent of IL-4 positive CD4 and CD8 in RSV stimulated spleen cells at all times p.i. while percent of IFN-gamma T cells significantly (p≤0.001) increased ≥75 days p.i. The shift from a Th2 to a Th1 biased T cell response in treated compared to untreated mice likely was directed by the much higher levels of T-box transcription factor (Tbet) (≥45% vs <10%) in CD4 and CD8 T cells and lower levels of Gata-3 (≤2% vs ≥6%) in CD4 T cells in peptide stimulated, day 75 p.i. spleen cells. These data show that the RSV G protein affects both humoral and cellular adaptive immune responses and induction of 131-2G-like antibodies might improve the safety and long term efficacy of an RSV vaccine. IMPORTANCE: The data in this report suggest that the RSV G protein not only contributes to disease but also dampens the host immune response to infection. Both effects of G likely contribute to difficulties in achieving an effective vaccine. The ability of mAb 131-2G to block these effects of G suggests that inducing antibodies similar to 131-2G should prevent disease and enhance the adaptive immune response with later RSV infection. The fact that 131-2G binds to the 13 aa region conserved among all strains and flanking sequences are conserved within Group A or within Group B strains, simplifies the task of developing a vaccine to induce 131-2G-like antibodies. If our findings in mice apply to humans, then including the 131-2G binding region of G in a vaccine should improve its safety and efficacy.

BACKGROUND: In April 2012, the Jordan Ministry of Health (JMoH) investigated an outbreak of lower respiratory illnesses at a hospital in Jordan; two fatal cases were retrospectively confirmed by rRT-PCR to be the first detected cases of Middle East Respiratory Syndrome (MERS-CoV). METHODS: Epidemiologic and clinical characteristics of selected potential cases were assessed through serum blood specimens, medical chart reviews and interviews with surviving outbreak members, household contacts, and healthcare personnel. Cases of MERS-CoV infection were identified using three U.S. Centers for Disease Control and Prevention (CDC) serologic tests for detection of anti-MERS-CoV antibodies. RESULTS: Specimens and interviews were obtained from 124 subjects. Seven previously unconfirmed individuals tested positive for anti-MERS-CoV antibodies by at least two of three serologic tests, in addition to two fatal cases identified by rRT-PCR. The case fatality rate among the nine total cases was 22%. Six cases were healthcare workers at the outbreak hospital, yielding an attack rate of 10% among potentially exposed outbreak hospital personnel. There was no evidence of MERS-CoV transmission at two transfer hospitals having acceptable infection control practices. CONCLUSION: Novel serological tests allowed for the detection of otherwise unrecognized cases of MERS-CoV infection among contacts of a Jordan hospital-associated respiratory illness outbreak in April 2012, resulting in a total of nine test-positive cases. Serologic results suggest that further spread of this outbreak to transfer hospitals did not occur. Most cases had no major, underlying medical conditions; none were on hemodialysis. Our observed case fatality was lower than has been reported from outbreaks elsewhere.

Since mid-March 2014, the frequency with which cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection have been reported has increased, with the majority of recent cases reported from Saudi Arabia and United Arab Emirates (UAE). In addition, the frequency with which travel-associated MERS cases have been reported and the number of countries that have reported them to the World Health Organization (WHO) have also increased. The first case of MERS in the United States, identified in a traveler recently returned from Saudi Arabia, was reported to CDC by the Indiana State Department of Health on May 1, 2014, and confirmed by CDC on May 2. A second imported case of MERS in the United States, identified in a traveler from Saudi Arabia having no connection with the first case, was reported to CDC by the Florida Department of Health on May 11, 2014. The purpose of this report is to alert clinicians, health officials, and others to increase awareness of the need to consider MERS-CoV infection in persons who have recently traveled from countries in or near the Arabian Peninsula. This report summarizes recent epidemiologic information, provides preliminary descriptions of the cases reported from Indiana and Florida, and updates CDC guidance about patient evaluation, home care and isolation, specimen collection, and travel as of May 13, 2014.

We conducted an epidemiologic investigation among survivors of a Middle East Respiratory Syndrome coronavirus (MERS-CoV) outbreak in Jordan.A second trimester stillbirth occurred during the course of an acute respiratory illness which was attributed to MERS-CoV, based on exposure history and positive MERS-CoV serology.This is the first occurrence of stillbirth during an infection with MERS-CoV and may have bearing upon the surveillance and management of pregnant women in settings of unexplained respiratory illness potentially due to MERS-CoV. Future prospective investigations of MERS-CoV should ascertain pregnancy status and obtain further pregnancy-related data, including biological specimens for confirmatory testing.

Respiratory syncytial virus (RSV) is a respiratory tract pathogen that causes significant morbidity and mortality in children aged <5 years (most disease occurs at age <1 year) and is a major public health burden worldwide. More than 90% of children are infected at least once with RSV before the age of 2 years [1–3]. RSV accounts for approximately 70% of hospitalizations due to bronchiolitis [1, 4]. In the United States alone, the estimated healthcare costs associated with RSV hospitalizations exceed $950 million, making it a significant economic burden [5]. Further, the RSV burden is disproportionately greater in children aged <5 years living in developing countries [3]. RSV infection does not confer long-term protection, as reinfections occur throughout life, which poses a significant disease risk in individuals with cardiopulmonary disease, immunocompromised patients, and the elderly [7]. In the elderly, complications of RSV infection often result from exacerbation of underlying pulmonary and cardiac disease. [7]. | A member of the Paramyxoviridae family, Pneumovirus genus, RSV exists as an enveloped virus containing a negative-sense, single-stranded RNA genome. The genome encodes for the following 11 proteins: nonstructural proteins (NS1, NS2, and M2-2), the viral nucleocapsid protein (N), phosphoprotein (P), matrix (M), RNA-dependent RNA polymerase (L), M2-1, and 3 surface glycoproteins (G [attachment], F [fusion], and SH [small hydrophobic]). There are 2 RSV major groups, A and B, and multiple genotypes within each group. The protective immune response to RSV infection is primarily directed against the 2 major surface viral glycoproteins, F and G. The F glycoprotein seems most important for induction of protective immunity and is associated with a high serum neutralizing antibody response as well as activation of CD14 and Toll-like receptor-4 (TLR-4) [8]. RSV F protein undergoes structural rearrangement during the fusion process. Antigenic sites on the postfusion form of the protein have been associated with a range of neutralizing activity. However, recent evidence suggests that most of the F protein–specific neutralizing antibodies in human sera are directed against the prefusion form of the RSV F protein. Thus, the antigenic nature of the RSV F protein may have important implications for prophylaxis and vaccine development [9]. The RSV G protein has been implicated in the pathogenesis of disease after primary infection and formalin-inactivated (FI-RSV)–enhanced disease [6]. The highest degree of antigenic diversity in RSV is found in the RSV G protein. This diversity may play an important role in viral pathogenesis by facilitating immune evasion. The ability of this protein to evade or inhibit the host immune response may complicate vaccine development. RSV binds to several surface ligands, including cellular glycosaminoglycans, CX3CR1 [10], ICAM-I [11], Annexin-II [12], and nucleolin [13].

Respiratory syncytial virus (RSV) is a high priority target for vaccine development. One concern in RSV vaccine development is that a non-live virus vaccine would predispose for enhanced disease similar to that seen with the formalin inactivated RSV (FI-RSV) vaccine. Since a mAb specific to RSV G protein can reduce pulmonary inflammation and eosinophilia seen after RSV infection of FI-RSV vaccinated mice, we hypothesized that RSV G peptides that induce antibodies with similar reactivity may limit enhanced disease after subunit or other non-live RSV vaccines. In support of this hypothesis, we show that FI-RSV vaccinated mice administered RSV G peptide vaccines had a significant reduction in enhanced disease after RSV challenge. These data support the importance of RSV G during infection to RSV disease pathogenesis and suggest that use of appropriately designed G peptide vaccines to reduce the risk of enhanced disease with non-live RSV vaccines merits further study.

Respiratory syncytial virus (RSV) belongs to the family Paramyxoviridae and is the single most important cause of serious lower respiratory tract infections in young children, yet no highly effective treatment or vaccine is available. Increased airway resistance and increased airway mucin production are two manifestations of RSV infection in children. RSV rA2-line19F infection induces pulmonary mucous production and increased breathing effort in BALB/c mice and provides a way to assess these manifestations of RSV disease in an animal model. In the present study, we investigated the effect of prophylactic treatment with the F(ab')2 form of the anti-G protein monoclonal antibody (MAb) 131-2G on disease in RSV rA2-line19F-challenged mice. F(ab')2 131-2G does not affect virus replication. It and the intact form that does decrease virus replication prevented increased breathing effort and airway mucin production, as well as weight loss, pulmonary inflammatory-cell infiltration, and the pulmonary substance P and pulmonary Th2 cytokine levels that occur in mice challenged with this virus. These data suggest that the RSV G protein contributes to prominent manifestations of RSV disease and that MAb 131-2G can prevent these manifestations of RSV disease without inhibiting virus infection.

The apical and basolateral surfaces of airway epithelial cells demonstrate directional responses to pathogen exposure in vivo. Thus, ideal in vitro models for examining cellular responses to respiratory pathogens polarize, forming apical and basolateral surfaces. One such model is differentiated normal human bronchial epithelial cells (NHBE). However, this system requires lung tissue samples, expertise isolating and culturing epithelial cells from tissue, and time to generate an air-liquid interface culture. Calu-3 cells, derived from a human bronchial adenocarcinoma, are an alternative model for examining the response of proximal airway epithelial cells to respiratory insult, pharmacological compounds, and bacterial and viral pathogens, including influenza virus, rhinovirus and severe acute respiratory syndrome - associated coronavirus. Recently, we demonstrated that Calu-3 cells are susceptible to respiratory syncytial virus (RSV) infection in a manner consistent with NHBE . Here, we detail the establishment of a polarized, liquid-covered culture (LCC) of Calu-3 cells, focusing on the technical details of growing and culturing Calu-3 cells, maintaining cells that have been cultured into LCC, and we present the method for performing respiratory virus infection of polarized Calu-3 cells. To consistently obtain polarized Calu-3 LCC, Calu-3 cells must be carefully subcultured before culturing in Transwell inserts. Calu-3 monolayer cultures should remain below 90% confluence, should be subcultured fewer than 10 times from frozen stock, and should regularly be supplied with fresh medium. Once cultured in Transwells, Calu-3 LCC must be handled with care. Irregular media changes and mechanical or physical disruption of the cell layers or plates negatively impact polarization for several hours or days. Polarization is monitored by evaluating trans-epithelial electrical resistance (TEER) and is verified by evaluating the passive equilibration of sodium fluorescein between the apical and basolateral compartments. Once TEER plateaus at or above 1,000 Omegaxcm(2), Calu-3 LCC are ready to use to examine cellular responses to respiratory pathogens.

Therapeutic options to control respiratory syncytial virus (RSV) are limited, thus development of new therapeutics is high priority. Previous studies with a monoclonal antibody (mAb) reactive to an epitope proximal to the central conserved region (CCR) of RSV G protein (mAb 131-2G) showed therapeutic efficacy for reducing pulmonary inflammation RSV infection in BALB/c mice. Here, we show a protective effect in RSV-infected mice therapeutically treated with a mAb (130-6D) reactive to an epitope within the CCR of G protein, while treatment with a mAb specific for a carboxyl G protein epitope had no effect. Combined treatment with mAbs 130-6D and 131-2G significantly decreased RSV-associated pulmonary inflammation compared to either antibody alone. The results suggest that anti-RSV G protein mAbs that react at or near the CCR and can block RSV G protein-mediated activities are effective at preventing RSV disease and may be an effective strategy for RSV therapeutic treatment.

Respiratory syncytial virus (RSV) is the most common cause of serious lower respiratory illness in infants and young children worldwide, making it a high priority for development of strategies for prevention and treatment. RSV can cause repeat infections throughout life, with serious complications in elderly and immunocompromised patients. Previous studies indicate that the RSV G protein binds through a CX3C chemokine motif to the host chemokine receptor, CX3CR1, and modulates the inflammatory immune response. In the current study, we examined the contribution of CX3CR1 to the immune response to RSV infection in mice. CX3CR1-deficient mice showed an impaired innate immune response to RSV infection, characterized by substantially decreased NK1.1(+) natural killer, CD11b(+), and RB6-8C5(+) polymorphonuclear cell trafficking to the lung and reduced IFNgamma production compared with those in wildtype control mice. Leukocytes from CX3CR1-deficient mice were poorly chemotactic toward RSV G protein and CX3CL1. These results substantiate the importance of the RSV G CX3C-CX3CR1 interaction in the innate immune response to RSV infection.

Human coronaviruses are one of the main causes of upper respiratory tract infections in humans. While more often responsible for mild illness, they have been associated with illnesses that require hospitalization. In this study, an assay for one of the human coronaviruses, OC43, was developed using a truncated recombinant nucleocapsid (N) protein antigen in an enzyme immunosorbent assay (ELISA) and evaluated using serum collected from HCoV-OC43-infected patients, healthy adults, and patients with other respiratory virus infections. Results showed that the diagnostic sensitivity and specificity of the assay were 90.9% (10/11) and 82.9% (39/47), respectively. To evaluate the clinical utility of the ELISA, serum samples collected from patients during an outbreak of HCoV-OC43 infection and previously identified as positive by HCoV-OC43 whole N ELISA were screened resulting in 100% diagnosis agreement between the testing methods. These results suggest that this assay offers a reliable method to detect HCoV-OC43 infection and may be a useful tool in coronavirus seroepidemiological studies.

Respiratory syncytial virus (RSV) replication is primarily limited to the upper respiratory tract epithelium and primary, differentiated normal human bronchial epithelial cells (NHBE) have, therefore, been considered a good system for in vitro analysis of lung tissue response to respiratory virus infection and virus-host interactions. However, NHBE cells are expensive, difficult to culture, and vary with the source patient. An alternate approach is to use a continuous cell line that has features of bronchial epithelial cells such as Calu-3, an epithelial cell line derived from human lung adenocarcinoma, as an in vitro model of respiratory virus infection. The results show that Calu-3 fully polarize when grown on permeable supports as liquid-covered cultures. Polarized Calu-3 are susceptible to RSV infection and release infectious virus primarily from the apical surface, consistent with studies in NHBE cells. The data demonstrate that polarized Calu-3 may serve as a useful in vitro model to study host responses to RSV infection.

Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in infants and young children and an important pathogen of the elderly and immune suppressed. The only intervention currently available is a monoclonal antibody against the RSV fusion protein, which has shown utility as a prophylactic for high-risk premature infants, but which has not shown postinfection therapeutic efficacy in the specific RSV-infected populations studied. Thus, for the major susceptible populations, there remains a great need for effective treatment. Recent results support monoclonal antibody targeting of the RSV G-protein for therapeutic use. This objective encompasses a dual mechanism: reduction in the ability of RSV G-protein to distort the host innate immune response, and direct complement-mediated antiviral activity.