A person-to-person transmission cluster of severe fever with thrombocytopenia syndrome characterized by mixed viral infections with familial and nosocomial clustering.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease with sporadic occurrence and high mortality. Herein, we report an example of the in-hospital transmission of SFTS virus (SFTSV) infections with familial and nosocomial clustering in Zhejiang Province, eastern China, from March to April 2023. The epidemiological investigation and genomic analysis revealed that at least eight suspected cases of SFTS occurred in this cluster, including one death and one asymptomatic case. Our report reemphasizes the risk of familial and nosocomial SFTSV infections in healthcare settings and the urgent need for the long-term systematic surveillance of SFTSV evolution in humans and animals in the eastern coastal regions of China.

Estimation of Incubation Period of Mpox during 2022 Outbreak in Pereira, Colombia.

We estimated the incubation period for mpox during an outbreak in Pereira, Colombia, using data from 11 confirmed cases. Mean incubation period was 7.1 (95% CI 4.9-9.9) days, consistent with previous outbreaks. Accurately estimating the incubation period provides insights into transmission dynamics, informing public health interventions and surveillance strategies.

[Human monkeypox (Mpox)]. / Humane Affenpocken (Mpox).

Until recently, human monkeypox (Mpox) were rarely observed outside of Africa, where the Mpox virus (MPXV) is endemic in some regions. In early May 2022, a global Mpox outbreak occurred. Crucial to this outbreak was human-to-human transmission during sexual activity. In particular, young men who have sex with men (MSM) became ill. In July 2022, this Mpox epidemic was declared a public health emergency of international concern by the World Health Organization. As of 26 September 2023, 90,618 confirmed cases of Mpox have been reported worldwide, with Germany accounting for around 3700 cases. The strongest increase in incidence occurred from May to mid-August 2022; since then, the number of cases has declined significantly as a result of intensive prevention efforts (education, vaccination). Currently, there are only sporadic, smaller outbreaks-in Germany (Berlin) most recently in August 2023. Despite the current calm epidemiological situation worldwide, isolated cases must therefore still be expected in Germany. The clinical picture of the "new" clade IIb-associated Mpox variant, which is mostly transmitted sexually from person to person, differs markedly from that of the "classical" Mpox (clades I and IIa), which, apart from rapidly breaking human infection chains, essentially occur as a zoonosis.

Potential for Person-to-Person Transmission of Henipaviruses: A Systematic Review of the Literature.

Nipah virus Bangladesh (NiVB) is a bat-borne zoonosis transmitted between people through the respiratory route. The risk posed by related henipaviruses, including Hendra virus (HeV) and Nipah virus Malaysia (NiVM), is less clear. We conducted a broad search of the literature encompassing both human infections and animal models to synthesize evidence about potential for person-to-person spread. More than 600 human infections have been reported in the literature, but information on viral shedding was only available for 40 case-patients. There is substantial evidence demonstrating person-to-person transmission of NiVB, and some evidence for NiVM. Less direct evidence is available about the risk for person-to-person transmission of HeV, but animals infected with HeV shed more virus in the respiratory tract than those infected with NiVM, suggesting potential for transmission. As the group of known henipaviruses continues to grow, shared protocols for conducting and reporting from human investigations and animal experiments are urgently needed.

Andes Virus Genome Mutations That Are Likely Associated with Animal Model Attenuation and Human Person-to-Person Transmission.

We performed whole-genome sequencing with bait enrichment techniques to analyze Andes virus (ANDV), a cause of human hantavirus pulmonary syndrome. We used cryopreserved lung tissues from a naturally infected long-tailed colilargo, including early, intermediate, and late cell culture, passages of an ANDV isolate from that animal, and lung tissues from golden hamsters experimentally exposed to that ANDV isolate. The resulting complete genome sequences were subjected to detailed comparative genomic analysis against American orthohantaviruses. We identified four amino acid substitutions related to cell culture adaptation that resulted in attenuation of ANDV in the typically lethal golden hamster animal model of hantavirus pulmonary syndrome. Changes in the ANDV nucleocapsid protein, glycoprotein, and small nonstructural protein open reading frames correlated with mutations typical for ANDV strains associated with increased virulence in the small-animal model. Finally, we identified three amino acid substitutions, two in the small nonstructural protein and one in the glycoprotein, that were only present in the clade of viruses associated with efficient person-to-person transmission. Our results indicate that there are single-nucleotide polymorphisms that could be used to predict strain-specific ANDV virulence and/or transmissibility. IMPORTANCE Several orthohantaviruses cause the zoonotic disease hantavirus pulmonary syndrome (HPS) in the Americas. Among them, HPS caused by Andes virus (ANDV) is of great public health concern because it is associated with the highest case fatality rate (up to 50%). ANDV is also the only orthohantavirus associated with relatively robust evidence of person-to-person transmission. This work reveals nucleotide changes in the ANDV genome that are associated with virulence attenuation in an animal model and increased transmissibility in humans. These findings may pave the way to early severity predictions in future ANDV-caused HPS outbreaks.

Clinical and Epidemiological Features of Hospitalized and Ambulatory Patients with Human Monkeypox Infection: A Retrospective Observational Study in Portugal.

Monkeypox, a neglected and re-emergent zoonotic disease caused by monkeypox virus (MPXV) infection, has been endemic in Central and Western Africa for decades. More recently, an outbreak has spread to a global level, occurring in sites with no previous reported cases and being clustered among men who have sex with men, suggesting new modes of transmission. There is an urgent need for research for a better understanding of the genomic evolution and changing epidemiology of the Orthopoxvirus group. Our work aimed to characterize the clinical and epidemiological features of a cohort of patients with MPXV infection in a Portuguese hospital, admitted between 5 May and 26 July 2022. In this retrospective observational study, aggregate data of a case series on the presentation, clinical course, and outcomes of confirmed MPXV infections are reported. The study included 40 men and 1 woman, with a mean age of 37.2 years old; 92.7% identified as men who have sex with men, 90.2% had unprotected sex or sex with multiple or anonymous partners in the previous month, and 39.0% reported to have had sex with an MPXV-confirmed case; 59.5% had previously known human immunodeficiency virus (HIV) infection, all of whom were under antiretroviral therapy, and no patients had acquired immunodeficiency syndrome (AIDS) criteria. About a quarter of patients were observed only a week after symptom onset. All patients had skin or mucosal lesions and the anogenital region was the most frequent lesion site. There were no statistically significant clinical differences between HIV-positive and negative individuals. Four patients were admitted to the inpatient clinic, two of whom had proctitis with difficult-to-manage anal pain. There were no reported deaths. Our findings suggest the sexual route as a relevant mode of transmission of MPXV and confirm the mostly benign presentation of this disease.

Oral and ocular transmission of severe fever with thrombocytopenia syndrome virus.

Background: Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne bunyavirus that could cause a severe hemorrhagic fever termed SFTS with a high fatality rate of up to 30%. Importantly, SFTSV is frequently transmitted from person-to-person and patients' blood or excreta are considered as the risk factors for transmission of SFTSV. However, the mechanism of person-to-person transmission of SFTSV is still elusive. Methods: In this study, wild-type (WT) C57BL/6 J mice and a lethal SFTSV mouse model IFNAR-/- A129 mice were utilized to evaluate whether SFTSV could be transmitted via oral or ocular routes. C57BL/6 J mice were inoculated with cell-cultured SFTSV via oral and ocular inoculation. IFNAR-/- A129 mice were inoculated with cell-cultured SFTSV or SFTSV infected mouse acute sera via oral and ocular inoculation. Results: We found that SFTSV antibody positive rates in C57BL/6 J mice were 70% (7/10) and 30% (3/10) in the oral inoculation group and ocular inoculation group, respectively on day 21 post SFTSV inoculation. The mortality rates of IFNAR-/- mice with oral and ocular inoculation of cell-cultured SFTSV were 100% and 83.33% (5/6), respectively on day 6 post inoculation. The mortality rates of IFNAR-/- mice with oral and ocular inoculation of SFTSV infected mouse acute serum were 100% and 66.67% (4/6), respectively on day 9 post inoculation. Conclusions: Together, our results show that SFTSV can be transmitted effectively through oral and ocular membrane, suggesting exposure to SFTS positive excreta may be a high-risk factor of nosocomial transmission of SFTSV in hospitals and/or families. Family members and healthcare workers should be protected properly during taking care of SFTS patients to prevent SFTSV nosocomial infection.

Occupational Characteristics and Management Measures of Sporadic COVID-19 Outbreaks From June 2020 to January 2021 in China: The Importance of Tracking Down "Patient Zero".

There are occupational disparities in the risk of contracting COVID-19. Occupational characteristics and work addresses play key roles in tracking down "patient zero." The present descriptive analysis for occupational characteristics and management measures of sporadic COVID-19 outbreaks from June to December 2020 in China offers important new information to the international community at this stage of the pandemic. These data suggest that Chinese measures including tracking down "patient zero," launching mass COVID-19 testing in the SARS-CoV-2-positive areas, designating a new high- or medium-risk area, locking down the corresponding community or neighborhood in response to new COVID-19 cases, and basing individual methods of protection on science are effective in reducing the transmission of the highly contagious SARS-CoV-2 across China.

Person-to-Person Transmission of Avian Influenza A (H7N9) Among Family Members in Eastern China, 2016.

OBJECTIVE: Human infections with avian influenza A (H7N9) virus are associated with exposure to poultry and live poultry markets, but the evidence of person-to-person transmission remains limited. This study reports a suspected person-to-person transmission of H7N9 virus, and explores what factors influenced this transmission. METHODS: We interviewed 2 patients with H7N9 infection and their family members as well as health-care workers. Samples from the patients and environments were tested by real-time reverse transcription-polymerase chain reaction. RESULTS: The index patient became ill 5 to 6 days after his last exposure to the poultry bought in the market of Weimiao town. The second patient, the sister of the index patient, who had sustained intensive and unprotected close contact with the index patient, had no exposure to poultry. This study documents that the H7N9 virus was transmitted directly from the index patient to his sister. CONCLUSIONS: Our findings suggest that person-to-person transmission may be associated with sustained close contact with the patient during his onset of early stage, when the H7N9 viral shedding increases sharply.

The Genomic Physics of COVID-19 Pathogenesis and Spread.

Coronavirus disease (COVID-19) spreads mainly through close contact of infected persons, but the molecular mechanisms underlying its pathogenesis and transmission remain unknown. Here, we propose a statistical physics model to coalesce all molecular entities into a cohesive network in which the roadmap of how each entity mediates the disease can be characterized. We argue that the process of how a transmitter transforms the virus into a recipient constitutes a triad unit that propagates COVID-19 along reticulate paths. Intrinsically, person-to-person transmissibility may be mediated by how genes interact transversely across transmitter, recipient, and viral genomes. We integrate quantitative genetic theory into hypergraph theory to code the main effects of the three genomes as nodes, pairwise cross-genome epistasis as edges, and high-order cross-genome epistasis as hyperedges in a series of mobile hypergraphs. Charting a genome-wide atlas of horizontally epistatic hypergraphs can facilitate the systematic characterization of the community genetic mechanisms underlying COVID-19 spread. This atlas can typically help design effective containment and mitigation strategies and screen and triage those more susceptible persons and those asymptomatic carriers who are incubation virus transmitters.

No Evidence of Re-infection or Person-to-Person Transmission in Cured COVID-19 Patients in Guangzhou, a Retrospective Observational Study.

Objectives: To clarify the clinical characteristics of cured patients with coronavirus disease (COVID-19), and to clarify the re-infection and person-to-person transmission in the cured. Methods: A total of 187 cured COVID-19 patients with antibody test were followed up every 2 weeks in this retrospective observational study. Assessment for general condition, symptoms, epidemiological contact history, polymerase chain reaction (PCR) assay, and antibody tests were performed and recorded. Information from Guangzhou CDC was also screened. Results: There were 33 (17.6%) patients with negative results for IgG and 35 (18.7%) patients with positive results for IgM. The average days of antibody detection from disease onset were 53.0. PCR assay was positive in 10 (5.3%) patients during the follow-up. Neither IgG nor IgM results showed a relationship with PCR test results (all P > 0.05). Neither re-infection nor person-to-person transmission was found in the cured patients. Factors associated with appearance of antibody comprised hospitalization days (OR: 1.06, 95%CI: 1.02-1.11, P = 0.006) and antibiotics treatment (OR: 3.50, 95%CI: 1.40-8.77, P = 0.007). Conclusions: In our study, no evidence of person-to-person transmission was found in cured COVID-19 patients. There seemed to be no re-infection in the cured COVID-19 patients in Guangzhou. These finding suggest that the cured do not cause the spread of disease. Additionally, neither IgG nor IgM can be used to replace the PCR test in cured patients.

The Social Distancing Imposed To Contain COVID-19 Can Affect Our Microbiome: a Double-Edged Sword in Human Health.

Hygienic measures imposed to control the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and contain COVID-19 have proven effective in controlling the pandemic. In this article, we argue that these measures could impact the human microbiome in two different and disparate ways, acting as a double-edged sword in human health. New lines of research have shown that the diversity of human intestinal and oropharyngeal microbiomes can shape pulmonary viral infection progression. Here, we suggest that the disruption in microbial sharing, as it is associated with dysbiosis (loss of bacterial diversity associated with an imbalance of the microbiota with deleterious consequences for the host), may worsen the prognosis of COVID-19 disease. In addition, social detachment can also decrease the rate of transmission of antibiotic-resistant bacteria. Therefore, it seems crucial to perform new studies combining the pandemic control of COVID-19 with the diversity of the human microbiome.

Three infection clusters related with potential pre-symptomatic transmission of coronavirus disease (COVID-19), Shanghai, China, January to February 2020.

We report three clusters related with potential pre-symptomatic transmission of coronavirus disease (COVID-19) between January and February 2020 in Shanghai, China. Investigators interviewed suspected COVID-19 cases to collect epidemiological information, including demographic characteristics, illness onset, hospital visits, close contacts, activities' trajectories between 14 days before illness onset and isolation, and exposure histories. Respiratory specimens of suspected cases were collected and tested for SARS-CoV-2 by real-time reverse-transcriptase polymerase chain reaction (rRT-PCR) assay. The interval between the onset of illness in the primary case and the last contact of the secondary case with the primary case in our report was 1 to 7 days. In Cluster 1 (five cases), illness onset in the five secondary cases was 2 to 5 days after the last contact with the primary case. In Cluster 2 (five cases) and Cluster 3 (four cases), the illness onset in secondary cases occurred prior to or on the same day as the onset in the primary cases. The study provides empirical evidence for transmission of COVID-19 during the incubation period and indicates that pre-symptomatic person-to-person transmission can occur following sufficient exposure to confirmed COVID-19 cases. The potential pre-symptomatic person-to-person transmission puts forward higher requirements for prevention and control measures.

The impact of novel coronavirus SARS-CoV-2 among healthcare workers in hospitals: An aerial overview.

The ongoing outbreak of COVID-19, caused by the novel coronavirus SARS-CoV-2, places healthcare workers at an increased risk of infection as they are in close contact with patients. In this article, we report an overview of cases of infected healthcare workers in China and Italy during the early periods of the COVID-19 epidemic. China's coronavirus response highlights the importance of implementing effective public health strategies. The authorities worldwide therefore, need to be extremely cautious when they implement stringent protective measures that safeguard healthcare workers in hospitals and counteract the threats created by the pandemic.

Person-to-Person Transmission of Andes Virus in Hantavirus Pulmonary Syndrome, Argentina, 2014.

Andes virus is unique among hantaviruses because it can be transmitted from person to person. This mechanism was previously supported by epidemiologic data and genetic evidence based only on partial sequences. We used full-length virus sequencing to confirm person-to-person transmission of this virus in a cluster of 3 cases in Argentina in 2014.

Transmission of bacteria in bronchiectasis and chronic obstructive pulmonary disease: Low burden of cough aerosols.

BACKGROUND AND OBJECTIVE: Aerosol transmission of Pseudomonas aeruginosa has been suggested as a possible mode of respiratory infection spread in patients with cystic fibrosis (CF); however, whether this occurs in other suppurative lung diseases is unknown. Therefore, we aimed to determine if (i) patients with bronchiectasis (unrelated to CF) or chronic obstructive pulmonary disease (COPD) can aerosolize P. aeruginosa during coughing and (ii) if genetically indistinguishable (shared) P. aeruginosa strains are present in these disease cohorts. METHODS: People with bronchiectasis or COPD and P. aeruginosa respiratory infection were recruited for two studies. Aerosol study: Participants (n = 20) underwent cough testing using validated cough rigs to determine the survival of P. aeruginosa aerosols in the air over distance and duration. Genotyping study: P. aeruginosa sputum isolates (n = 95) were genotyped using the iPLEX20SNP platform, with a subset subjected to the enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) assay to ascertain their genetic relatedness. RESULTS: Aerosol study: Overall, 7 of 20 (35%) participants released P. aeruginosa cough aerosols during at least one of the cough aerosol tests. These cough aerosols remained viable for 4 m from the source and for 15 min after coughing. The mean total aerosol count of P. aeruginosa at 2 m was two colony-forming units. Typing study: No shared P. aeruginosa strains were identified. CONCLUSION: Low viable count of P. aeruginosa cough aerosols and a lack of shared P. aeruginosa strains observed suggest that aerosol transmission of P. aeruginosa is an unlikely mode of respiratory infection spread in patients with bronchiectasis and COPD.

Immunocytochemical and Ultrastructural Evidence Supporting That Andes Hantavirus (ANDV) Is Transmitted Person-to-Person Through the Respiratory and/or Salivary Pathways.

In South America Andes hantavirus (ANDV) is hosted by the rodent Oligoryzomys longicaudatus (also known as pygmy rice rat). In humans, ANDV causes Hantavirus Pulmonary Syndrome (HPS), with a fatality rate of about 40%. Epidemiologic and molecular evidence has shown that ANDV can be transmitted from person to person. Sin Nombre hantavirus, occurring in North America, and ANDV are genetically related, and both cause HPS with similar clinical evolution and mortality rate. However, only ANDV is transmitted from person to person. A recent hantavirus outbreak in a small village in Southern Argentine, with 29 HPS cases and 11 deaths has brought to mind that person-to-person transmission continues to be a public health emergency. The present investigation was aimed to understand how does ANDV actually spread between persons. Tissue samples of lung and salivary glands from infected Oligoryzomys longicaudatus and lethal cases of human HPS were investigated by bright field immunocytochemistry, multichannel immunofluorescence, and transmission electron microscopy. The findings are consistent with ANDV infection and replication in the lung alveolar epithelium and macrophages, and in the secretory cells of the submandibular salivary glands. In the lung of infected Oligoryzomys longicaudatus and human cases HPS, the bulk of immunoreactive hantavirus antigens was localized in epithelial cells of the alveolar walls and macrophages. The ultrastructural study supports that in the lung of HPS patients the virus replicates in the alveolar epithelial cells with virus particles being discharged into the alveolar lumen. Virus-like particles were seen within vacuoles of the lung macrophages. Considering that these macrophages can reach the conductive segments of the airways, their expectoration becomes a deadly bullet for ANDV transmission. In the submandibular glands of infected rodents and HPS cases, ANDV antigens were in capillary endothelium, the secretory cells and filling the lumen of the excretory pathway. It is proposed that in patients with HPS caused by ANDV the alveolar epithelium and macrophages would be the gate for the airway spreading of the virus, while the salivary glands are a target for virus replication and an exit pathway through saliva.

Microevolution and Patterns of Transmission of Shigella sonnei within Cyclic Outbreaks Shigellosis, Israel.

Whole-genome sequencing unveiled host and environment-related insights to Shigella sonnei transmission within cyclic epidemics during 2000-2012 in Israel. The Israeli reservoir contains isolates belonging to S. sonnei lineage III but of different origin, shows loss of tetracycline resistance genes, and little genetic variation within the O antigen: highly relevant for Shigella vaccine development.

Molecular epidemiology of blastocystosis in Malaysia: does seasonal variation play an important role in determining the distribution and risk factors of Blastocystis subtype infections in the Aboriginal community?

BACKGROUND: Alternating wet and dry seasons may play an important role in the acquisition and distribution of Blastocystis subtype infection in the tropics. This cross-sectional study was therefore conducted to provide the prevalence of Blastocystis and to determine the potential risk factors associated with each subtype during the wet and dry seasons in the Aboriginal community, Pahang, Malaysia. METHODS: A total of 473 faecal samples were collected: 256 (54.1%) and 217 (45.9%) samples were obtained during the wet (October-November 2014) and the dry season (June 2015), respectively. All fresh faecal samples were subjected to molecular analysis for subtype and allele identification. RESULTS: Of the 473 samples, 42.6% and 37.8% were positive for Blastocystis ST1, ST2, ST3 and ST4 during wet and dry seasons, respectively. Prevalence of Blastocystis ST1 was significantly higher during the wet season compared to the dry season (Z = 2.146, P < 0.05). Analysis of the association of each Blastocystis subtype with socioeconomic characteristics showed the presence of other family members infected with Blastocystis ST3 and the use of stored river water for domestic activities were the significant risk factors for Blastocystis ST3 infections during both seasons. Untreated water supply and low monthly household income (less or equal to RM 500) were the other significant risk factors for Blastocystis ST3 infections during wet and dry season, respectively. The presence of other family members with Blastocystis ST1 and ST2 was the only significant risk factor associated with ST1 and ST2 infections during both seasons. We hypothesise that transmission of Blastocystis ST1, ST2 and ST3 occurred from person to person during both seasons. The waterborne transmission was also identified as a mode of transmission of Blastocystis ST3. CONCLUSION: The significant risk factors identified in this study were important in the dynamic transmission of Blastocystis infections during both seasons. Provision of treated water supply and health education are affirmative actions to be taken to control Blastocystis infections in this community.

Zika Virus Infection in Patient with No Known Risk Factors, Utah, USA, 2016.

In 2016, Zika virus disease developed in a man (patient A) who had no known risk factors beyond caring for a relative who died of this disease (index patient). We investigated the source of infection for patient A by surveying other family contacts, healthcare personnel, and community members, and testing samples for Zika virus. We identified 19 family contacts who had similar exposures to the index patient; 86 healthcare personnel had contact with the index patient, including 57 (66%) who had contact with body fluids. Of 218 community members interviewed, 28 (13%) reported signs/symptoms and 132 (61%) provided a sample. Except for patient A, no other persons tested had laboratory evidence of recent Zika virus infection. Of 5,875 mosquitoes collected, none were known vectors of Zika virus and all were negative for Zika virus. The mechanism of transmission to patient A remains unknown but was likely person-to-person contact with the index patient.