ABSTRACT
An outbreak of severe pneumonia of unknown cause was reported in December 2019 in Wuhan, Hubei Province, China. The infectious virus was soon identified and named as 2019 novel coronavirus (2019-nCov). The name of the coronavirus infectious disease (COVID-19) was given by WHO on 11 February 2020. It has so far caused about 118 000 cases in 114 countries including China and was characterized as a pandemic by WHO on 11 March. We still face great challenges in control of the epidemic: uncertain initial source of infection, infected populations widely scattered, complex routs of transmission, populations generally susceptible, high contagiousness of the virus, and finally vaccines unlikely available in the near future.
ABSTRACT
One of the commonly accepted merits of cohort studies (CSs) refers to the exposure precedes outcome superior to other observational designs.We use Directed Acyclic Graphs to construct a causal graph among research populations under CSs.We notice that the substitution of research population in place of a susceptible one can be used for effect estimation.Its correctness depends on the outcome-free status of the substituted population and the performance of both screening and diagnosis regarding the outcomes under study at baseline.The temporal precedence of exposure over outcome occurs theoretically,despite the opposite happens in realities.Correct effect estimate is affected by both the suitability of population substitution and the validities of outcome identification and exclusion.
ABSTRACT
One of the commonly accepted merits of cohort studies (CSs) refers to the exposure precedes outcome superior to other observational designs.We use Directed Acyclic Graphs to construct a causal graph among research populations under CSs.We notice that the substitution of research population in place of a susceptible one can be used for effect estimation.Its correctness depends on the outcome-free status of the substituted population and the performance of both screening and diagnosis regarding the outcomes under study at baseline.The temporal precedence of exposure over outcome occurs theoretically,despite the opposite happens in realities.Correct effect estimate is affected by both the suitability of population substitution and the validities of outcome identification and exclusion.
ABSTRACT
The number of studies emphasizing the possible damage that acaricidal spray formulations can cause on engorged female ticks' reproductive parameters is small. The present study evaluated the deleterious effects of a spray formulation (dichlorvos 60% + chlorpyrifos 20%) on the reproductive parameters of a susceptible population of Rhipicephalus (B.) microplus females, using the Stall Test. The ticks were allocated randomly to treatments according to the mean numbers of females detached from each cow on days -3, -2 and -1 and the cattle pen location. The numbers of engorged female ticks that naturally detached from the cattle were counted daily from day 1 to day 30. For each group, 20 detached engorged female ticks or the available number collected daily were evaluated regarding reproductive parameters. Associations of organophosphates demonstrated elevated acaricidal efficacy, as well as deleterious effects on the reproductive parameters of R. (B.) microplus females. The engorged female weight (days 1 to 7), weight of egg masses (days 5 to 10) and larval hatching percentage (days 5 to 19) were decreased (P ≤ 0.05). It is possible that a formulation can lead to deleterious effects on R. (B.) microplus females when the tick population analyzed shows elevated sensitivity towards a particular formulation. However, further studies need to be conducted.
É relativamente pequeno o número de estudos que enfatiza os danos que uma formulação acaricida spray pode desencadear sobre os parâmetros reprodutivos das teleóginas. O presente estudo teve como objetivo avaliar os efeitos deletérios de uma formulação spray comercial (dichlorvos 60% + Clorpirifós 20%), sobre os parâmetros reprodutivos de uma população susceptível de R. (B.) microplus, desprendidas de bovinos experimentalmente infestados, utilizandose o teste de estábulo. Os animais foram alocados aos grupos de tratamentos de acordo com a contagem média de fêmeas desprendidas dos bovinos nos dias -3, -2 e -1. O número de teleóginas desprendidas foi quantificado do dia 1 ao 30. Para cada grupo, diariamente 20 fêmeas, ou a quantidade disponível, foram selecionadas e submetidas à avaliação dos parâmetros reprodutivos. A associação de organofosforados demonstrou elevada eficácia acaricida e também apresentou efeitos deletérios sob os parâmetros reprodutivos de Rhipicephalus (B.) microplus, diminuindo (P≤0,05) o peso das teleóginas (dos dias 1 ao 7), o peso da massa de ovos (dos dias 5 ao 10) e a eclodibilidade das larvas (dos dias 5 ao 19). Talvez uma formulação pode apresentar efeitos deletérios sobre os parâmetros reprodutivos de fêmeas de R. (B.) microplus, quando existe um elevado grau de sensibilidade dessa cepa de carrapato a um determinado composto. De qualquer maneira, futuros estudos devem ser realizados.
Subject(s)
Aged , Female , History, 17th Century , Humans , Male , Antimetabolites, Antineoplastic/therapeutic use , Floxuridine/therapeutic use , Fluorouracil/therapeutic use , Serous Membrane/pathology , Stomach Neoplasms/drug therapy , Chemotherapy, Adjuvant , Lymphatic Metastasis , Neoplasm Invasiveness , Neoplasm Staging , Prognosis , Postoperative Care/methods , Survival Rate , Stomach Neoplasms/pathologyABSTRACT
Objective To determine the genetic subtypes and susceptible population of Cryptoccocus neoformans in China. Methods We analyzed 129 strains of Cryptococcus neoformans isolated during the period from 1980 through 2006 in 18 Prov-inces and municipalities of central and eastern China using epidemiological method,PCR fingerprint,and multilocus sequence typing (MLST).Results About 71.5% (91/129)of the clinical strains were isolated from the patients without any recognizable immunodeficiency.Only 8.5% (11/129)of the strains were from AIDS patients.The remaining 20.9% (27/129)were from patients with underlying diseases other than HIV infection.Furthermore,PCR fingerprinting and MLST showed that serotype A strains exhibited a unique VNⅠsubtype,which was distinguishable from the reference VNⅠmolecular types.For convenience we named this unique genotype as VNⅠc.Conclusions People without any recognizable immunodeficiency are the main susceptible population of the 129 clinical strains of Cryptococcus neoformans ,which contrasts with the reports from other countries.The different genetic subtypes of Cryptococcus neoformans between China and other countries may contribute to such a difference.
ABSTRACT
The Korean peninsula has a long history of spring time dust clouds blown by winds from the arid deserts of Mongolia and China, these are called Yellow sand or Asian dust event. Public concern about the possible adverse effects of these dust events has increased, because the dust arrives in Korea after having passed over heavily industrialized eastern China. Most studies on the Asian dust have been focused on the physiochemical properties of the dust. Just several studies have been published on the matter of the health effects of the Asian dust both domestically and internationally. Even though the dust of crustal origin like the Asian dust is not considered as harmful as the dust from the exhaust gas, many people have experienced the eye symptoms and the respiratory symptoms such as cough, sputum, and chest tightness during the yellow sand period. However it is not clear that the increased risk of experiencing respiratory symptoms during the dust period leads to increased risk of hospitalization or mortality. Limited epidemiologic studies suggest that the aged people and the patients with cardiopulmonary disease are more susceptible to possible harmful effects of the Asian dust.