Land public transport is an important link within and between cities, and how to control the transmission of COVID-19 in land public transport is a critical issue in our daily lives. However, there are still many inconsistent opinions and views about the spread of SARS-CoV-2 in land public transport, which limits our ability to implement effective interventions. The purpose of this review is to overview the literature on transmission characteristics and routes of the epidemic in land public transport, as well as to investigate factors affecting its spread and provide feasible measures to mitigate the infection risk of passengers. We obtained 898 papers by searching the Web of Science, Pubmed, and WHO global COVID database by keywords, and finally selected 45 papers that can address the purpose of this review. Land public transport is a high outbreak area for COVID-19 due to characteristics like crowding, inadequate ventilation, long exposure time, and environmental closure. Different from surface touch transmission and drop spray transmission, aerosol inhalation transmission can occur not only in short distances but also in long distances. Insufficient ventilation is the most important factor influencing long-distance aerosol transmission. Other transmission factors (e.g., interpersonal distance, relative orientation, and ambient conditions) should be noticed as well, which have been summarized in this paper. To address various influencing factors, it is essential to suggest practical and efficient preventive measures. Among these, increased ventilation, particularly the fresh air (i.e., natural ventilation), has proven to effectively reduce indoor infection risk. Many preventive measures are also effective, such as enlarging social distance, avoiding face-to-face orientation, setting up physical partitions, disinfection, avoiding talking, and so on. As research on the epidemic has intensified, people have broken down many perceived barriers, but more comprehensive studies on monitoring systems and prevention measures in land public transport are still needed.

Healthcare-associated transmission was the second most common hepatitis B (HBV) and hepatitis C (HCV) transmission route according to 2006-2012 European surveillance data, but data quality and completeness issues hinder comprehensive characterisation of this important issue. We carried out a systematic review of published literature on healthcare-associated transmission of HBV or HCV in European Union (EU) and European Economic Area (EEA) countries and the United Kingdom to complement surveillance data and identify higher-risk settings. We searched the PubMed and Embase databases and grey literature over the period January 2006 to September 2021, for publications reporting transmission events after 2000 in the EU/EEA and UK related to a healthcare setting or procedure. We collected data on the country, number of patients, setting type and route of transmission. In 65 publications from 16 countries, 43 HBV and 48 HCV events were identified resulting in 442 newly infected patients. Most events were reported from Italy (7 HBV and 12 HCV), Germany (8 HBV and 5 HCV) and the United Kingdom (8 HBV and 5 HCV). The number of patients infected from a single source within an event ranged from 1 to 53. Five large outbreaks of over 20 cases were identified, including two in Poland and one each in Belgium, Hungary and Slovakia. The majority of transmission events occurred through blood transfusions or in dialysis units. However, there were a number of outbreaks in seemingly low risk settings such as CT/MRI scanning units. A failure to adequately follow infection prevention control (IPC) precautions was reported in 30% of included studies. Healthcare-associated transmission of hepatitis B and C continues to occur in a range of community and hospital settings across EU/EEA countries and often results in large outbreaks, although the true extent of the situation cannot be fully determined due to under-reporting. Strict IPC precautions should be implemented across all healthcare settings and regularly audited, and surveillance systems strengthened and standardised to allow for comprehensive and consistent reporting of nosocomial transmission of hepatitis across the EU.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has lasted for two years and caused millions of infections and deaths in humans. Although the origin of SARS-CoV-2 infection in humans remains unknown, infection in animals has been frequently reported in varieties of animals all over the world. Both experimental and natural infections of SARS-CoV-2 in different animal species provide useful information on viral host range and pathogenicity. As the pandemic continues to evolve, SARS-CoV-2 infection in animals will be expanding. In this review, we summarized SARS-CoV-2 testing and infection in animals as well as SARS-CoV-2 strains and transmission in animals. Current data showed that at least 18 different animal species tested positive for SARS-CoV-2. These 18 animal species belong to pet, captive, farmed, and wild animals. Fifteen of the eighteen animal species were known to be positive for the Delta variant and ten animal species were infected with two different types of variants. Human-to-animal, animal-to-animal, and animal-to-human transmission events were suggested in different outbreaks involved in animal infection with SARS-CoV-2. Continued testing, immunization, and surveillance are warranted.

The coronavirus disease 2019 (COVID-19) pandemic is still spreading all over the world. Although China quickly brought the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) under control in 2020, sporadic outbreaks have recurred from time to time. Outbreaks since June 2020 have suggested that the imported cold food supply chain is a major cause for the recurrence and spread of COVID-19. Here we review recurrent outbreaks in China from June 2020 to March 2021, and we analyse the main causes for recurrence and transmission by the supply of imported cold food from port to fork. Contaminated cold food or food packaging material can transmit the virus through \'person-to-thing-to-person\', by contrast with the classical \'person-to-person\' pathway. We decribe safety precautions for the food system, operating environment and people along the cold chain logistics. Surface disinfection and nucleic acid inspection are needed in each stage of the logistics of imported cold food supply.

The outbreak of Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2). Thus far, the virus has killed over 2,782,112 people and infected over 126,842,694 in the world (state 27 March 2021), resulting in a pandemic for humans. Based on the present data, SARS-CoV-2 transmission from animals to humans cannot be excluded. If mutations allowing breaking of the species barrier and enhancing transmissibility occurred, next changes in the SARS-CoV-2 genome, leading to easier spreading and greater pathogenicity, could happen. The environment and saliva might play an important role in virus transmission. Therefore, there is a need for strict regimes in terms of personal hygiene, including hand washing and surface disinfection. The presence of viral RNA is not an equivalent of active viral infection. The positive result of the RT-PCR method may represent either viral residues or infectious virus particles. RNA-based tests should not be used in patients after the decline of disease symptoms to confirm convalescence. It has been proposed to use the test based on viral, sub-genomic mRNA, or serological methods to find the immune response to infection. Vertical transmission of SARS-CoV-2 is still a little-known issue. In our review, we have prepared a meta-analysis of the transmission of SARS-CoV-2 from mother to child depending on the type of delivery. Our study indicated that the transmission of the virus from mother to child is rare, and the infection rate is not higher in the case of natural childbirth, breastfeeding, or contact with the mother. We hope that this review and meta-analysis will help to systemize knowledge about SARS-CoV-2 with an emphasis on diagnostic implications and transmission routes, in particular, mother-to-child transmission.

Droplets provide a well-known transmission media in the COVID-19 epidemic, and the particle size is closely related to the classification of the transmission route. However, the term \"aerosol\" covers most particle sizes of suspended particulates because of information asymmetry in different disciplines, which may lead to misunderstandings in the selection of epidemic prevention and control strategies for the public. In this review, the time when these droplets are exhaled by a patient was taken as the initial time. Then, all available viral loads and numerical distribution of the exhaled droplets was analyzed, and the evaporation model of droplets in the air was combined with the deposition model of droplet nuclei in the respiratory tract. Lastly, the perspective that physical spread affects the transmission risk of different size droplets at different times was summarized for the first time. The results showed that although the distribution of exhaled droplets was dominated by small droplets, droplet volume was proportional to the third power of particle diameter, meaning that the viral load of a 100 μm droplet was approximately 106 times that of a 1 μm droplet at the initial time. Furthermore, the exhaled droplets are affected by heat and mass transfer of evaporation, water fraction, salt concentration, and acid-base balance (the water fraction > 98%), which lead them to change rapidly, and the viral survival condition also deteriorates dramatically. The time required for the initial diameter (do) of a droplet to shrink to the equilibrium diameter (de, about 30% of do) is approximately proportional to the second power of the particle diameter, taking only a few milliseconds for a 1 μm droplet but hundreds of milliseconds for a 10 μm droplet; in other words, the viruses carried by the large droplets can be preserved as much as possible. Finally, the infectious droplet nuclei maybe inhaled by the susceptible population through different and random contact routes, and the droplet nuclei with larger de decompose more easily into tiny particles on account of the accelerated collision in a complex airway, which can be deposited in the higher risk alveolar region. During disease transmission, the infectious droplet particle size varies widely, and the transmission risk varies significantly at different time nodes; therefore, the fuzzy term \"aerosol\" is not conducive to analyzing disease exposure risk. Recommendations for epidemic prevention and control strategies are: 1) Large droplets are the main conflict in disease transmission; thus, even if they are blocked by a homemade mask initially, it significantly contains the epidemic. 2) The early phase of contact, such as close-contact and short-range transmission, has the highest infection risk; therefore, social distancing can effectively keep the susceptible population from inhaling active viruses. 3) The risk of the fomite route depends on the time in contact with infectious viruses; thus, it is important to promote good health habits (including frequent hand washing, no-eye rubbing, coughing etiquette, normalization of surface cleaning), although blind and excessive disinfection measures are not advisable. 4) Compared with the large droplets, the small droplets have larger numbers but carry fewer viruses and are more prone to die through evaporation.

The present article reviews the status of Chagas disease in Venezuela during the period 2003-2018, based on the detection of Trypanosoma cruzi-infection in 3,343 blood samples of individuals from rural localities and 182 patients referred from health centers to confirm presumptive clinical diagnostic. The study involved samples from 81 rural localities of 17 states located at different regions and ecological life zones of the country. Analysis by parasitological (fresh microscopic observation, hemoculture and Giemsa stained blood smears), serological (DAT, IFAT-polyvalent, IgM, IgG tests) and molecular (PCR) tests, revealed 10.7% seroprevalence and 42.8% T. cruzi-infection, in individuals from rural localities and referred patients, respectively. In both groups T. cruzi-infection was detected at any age, revealing active transmission in children under 10-years-old. Clinical profile detected in referred patients, showed significantly major number of symptoms in orally infected patients than in infected by vectorial route (P<0.01). Genetic characterization of T. cruzi isolates obtained from orally and vectorial transmitted acute Chagas disease in western Venezuela, revealed the circulation of DTUI and DTUIII in the former, and DTUI, DTUII and DTUIII in patients infected by vectorial route. DTUI predominated in both cases, and haplotype Ib was the most frequently found in this genotype. Statistical analysis of clinical profile - T. cruzi DTUs - transmission route relationships did not show association among these variables and, consequently, chagasic patient\'s clinical condition did not depend of T. cruzi genotype or its route of transmission. In addition, differences in clinical severity may be associated with host susceptibility and/or parasite load received by the human receptor in spite of the T. cruzi genotype itself. The epidemiological implications of the present findings are discussed, and the need for developing efficient tools as well as implementation of urgent and radical changes in the public health policy to control Chagas disease transmission in the Venezuelan territory are suggested.