Comparative efficiency of infecting laboratory animals via intravenous and subcutaneous administration of Schistosoma mansoni cercaria

Comparative study on effectiveness of intravenous and subcutaneous methods of infection of animals has shown that infection rate of helminths after the injection of equal dozes of cercariae under skin, into portal and femoral veins of golden hamsters does not differ significantly (42.6 +/- 4.2, 37.8 +/- 5.8 and 26.0 +/- 6.6 schistosomes, respectively). When using the above methods for cotton rats the infection rate was lower than that in golden hamsters. The most insignificant infection rate of parasites was recorded in both species after the injection of cercariae into the femoral vein. Results of the infection of golden hamsters with different dozes of cercariae have shown that with the increase of dozes of infectious material the infection rate of helminths rises during the experimental intestinal schistosomiasis only to a definite level, which is attained by the injection of cercariae into the portal vein in dozes lower than those used for subcutaneous infection.     

Nematodes as host resistance models for detection of immunotoxicity

Greater susceptibility to infection is a hallmark of compromised immune function in humans and animals, and is often considered the benchmark against which the predictive value of immune function tests are compared. The focus of this paper is resistance to infection with the parasitic nematode Trichinella spiralis as a model of host resistance. Topics include overviews of parasite biology, host immune responses that limit infection and methods used to evaluate the host response to infection. Detailed protocols are provided for adult and larval parasite counts, female parasite fecundity, parasite antigen-driven lymphocyte proliferation and antibody responses to infection.     

人胚胎干细胞支原体感染的检测和控制

目的：优化检测人胚胎干细胞支原体感染的方法,寻找控制支原体感染的途径。方法：利用hoeshest33258染色检测感染支原体的人胚胎干细胞,接触感染培养基的人胚胎成纤维细胞,比较两种方法检测效果;利用RNApolymeraseⅡ作为新的鉴定指标,直接检测感染支原体的人胚胎干细胞;利用抗支原体药物对感染细胞进行处理,检测处理后细胞的感染状态。结果：hoechest33258染色后,受支原体感染人胚胎干细胞检测效果不明显,接触感染培养基的人胚胎成纤维细胞在培养7天后有拉丝状染色分布;RNApolymeraseⅡ染色则能直接检测出受感染的人胚胎干细胞表面粘附的支原体;利用抗支原体药物Plasmocin对感染细胞进行处理后hoechest33258拉丝状染色基本消失,但持续培养后重新出现。结论：间接法使用hoechest33258染色或者直接利用RNApolymeraseⅡ染色都能够很好地检测人胚胎干细胞培养过程中的支原体感染。抗支原体药物Plasmocin能够有效减轻支原体感染情况,但是不能完全杀灭支原体。     

Monitoring adenovirus infections with on-line and off-line methods

Several known process monitoring methods were tested for their efficacy in the detection of adenovirus infections. The methods that we explored include several indirect indications of viral infections, including metabolic rate analysis, secondary gauges of respiration, cell size measurement, cell number and cell viability determination, and changes in capacitance. Direct indications of the adenovirus infection were also applied, including total viral particle and infectious particle measurements, as well as a flow cytometry method for detecting infected cells. All of the methods tested in the study provide some positive indication of an adenovirus infection. Many of the methods require repeated sampling, which may limit their utility in a manufacturing process. All of the indirect measures of viral infection may be limited by the fact that they do not uniquely identify an infection. The simplest monitoring methods appear to be detection of changes in respiration or the capacitance of the culture, both of which seem to provide a clear indication of an infection. Further work will be required to demonstrate that these indications are characteristic of only a successful and productive adenovirus infection.     

腹部大手术术后深部真菌感染的临床与真菌学分析

目的探讨腹部大手术术后深部真菌感染的危险因素及诊治措施。方法回顾性分析2006年1月～2009年6月期间我科腹部大手术术后合并深部真菌感染48例患者的临床和真菌学资料。结果 48例真菌感染患者共分离出56株菌株,其中白念珠菌占41.1%,是最主要的致病菌株。患者基础疾病和术后长期、多种广谱抗生素联合使用是深部真菌感染的重要因素。结论深部真菌感染是腹部大手术术后的重要并发症,白念珠菌仍然是主要病原菌。对术后患者深部真菌感染应采取积极预防、及时发现和有效治疗。     

Estimating treatment effects in studies of perinatal transmission of HIV

Fetal loss often precludes the ascertainment of infection status in studies of perinatal transmission of HIV. The standard analysis based on liveborn babies can result in biased estimation and invalid inference in the presence of fetal death. This paper focuses on the problem of estimating treatment effects for mother-to-child transmission when infection status is unknown for some babies. Minimal data structures for identifiability of parameters are given. Methods using full likelihood and the inverse probability of selection-weighted estimators are suggested. Simulation studies are used to show that these estimators perform well in finite samples. Methods are applied to the data from a clinical trial in Dar es Salaam, Tanzania. To validly estimate the treatment effect using likelihood methods, investigators should make sure that the design includes a mini-study among uninfected mothers and that efforts are made to ascertain the infection status of as many babies lost as possible. The inverse probability weighting methods need precise estimation of the probability of observing infection status. We can further apply our methodology to the study of other vertically transmissible infections which are potentially fatal pre- and perinatally.     

Comparative analysis of mycobacterial infections in wild striped bass Morone saxatilis from Chesapeake Bay

During an ongoing epizootic of mycobacteriosis, wild striped bass Morone saxatilis from Chesapeake Bay were analyzed using 3 methods for detection of either mycobacterial infection or associated granulomatous pathology. The specific detection techniques, which utilized aseptically collected splenic tissue, were histology, quantitative culture and nested PCR. Based on analysis of 118 samples, detection of infection differed significantly between the 3 methods (chi-square, p = 0.0007). Quantitative culture and nested PCR detected similar, higher rates of infection (69 and 75%, respectively) than the histological method (52%). Although primary PCR assays for a 924 to 940 bp segment of the mycobacterial 16S rRNA gene were positive for genomic DNA from mycobacterial cultures, a secondary, nested PCR reaction for an internal 300 bp gene segment was required in order to detect mycobacteria within splenic tissue. A similar rate of mycobacterial infection was present in fish collected from all sites tested. Although all detection methods found that striped bass age 4.0 to 4.9 yr had the highest positive incidence, nested PCR detected a higher frequency of mycobacterial infection in fish > or = 6.0 yr of age than the other 2 methods. Quantitative bacteriology was a more sensitive detection technique when the fish tissue contained < or = 10(3) mycobacteria g(-1).     

Inferring the Source of Transmission with Phylogenetic Data

Identifying the source of transmission using pathogen genetic data is complicated by numerous biological, immunological, and behavioral factors. A large source of error arises when there is incomplete or sparse sampling of cases. Unsampled cases may act as either a common source of infection or as an intermediary in a transmission chain for hosts infected with genetically similar pathogens. It is difficult to quantify the probability of common source or intermediate transmission events, which has made it difficult to develop statistical tests to either confirm or deny putative transmission pairs with genetic data. We present a method to incorporate additional information about an infectious disease epidemic, such as incidence and prevalence of infection over time, to inform estimates of the probability that one sampled host is the direct source of infection of another host in a pathogen gene genealogy. These methods enable forensic applications, such as source-case attribution, for infectious disease epidemics with incomplete sampling, which is usually the case for high-morbidity community-acquired pathogens like HIV, Influenza and Dengue virus. These methods also enable epidemiological applications such as the identification of factors that increase the risk of transmission. We demonstrate these methods in the context of the HIV epidemic in Detroit, Michigan, and we evaluate the suitability of current sequence databases for forensic and epidemiological investigations. We find that currently available sequences collected for drug resistance testing of HIV are unlikely to be useful in most forensic investigations, but are useful for identifying transmission risk factors.     

A lethal model of Leptospira infection in hamster nasal mucosa

Leptospirosis is a fatal zoonosis caused by contact between skin or a mucosal surface and contaminated soil or water. Hamsters were infected by intraperitoneal injection fto establish experimental leptospirosis, which is not a natural route of infection. There are no reports of nasal mucosal infection in hamsters. In this study, infection of the nasal mucosa was performed to establish a model of natural infection. Both methods of infection can cause lethal models with similar symptoms in the later stages of infection, such as weight loss, blood concentration, increased neutrophils (GRAN), and decreased lymphocytes (LYM) in the blood, severe organ damage and liver function obstruction. The burden of Leptospira in the organs and blood was lower in the mucosal inoculation groups at 1 day after infection. However, mucosal infection induced a higher Leptospira burden in urine than intraperitoneal infection in the late stages of infection. After nasal mucosal infection, antibody levels were higher and lasted longer. These results indicated that the route of nasal mucosal infection is a good choice for studying leptospirosis in hamsters.     

Dioctophyme renale (Goeze, 1782) (Nematoda,Dioctophymidae) parasitic in mammals other than humans: A comprehensive review

A comprehensive review of the infection of mammals with the nematode Dioctophyme renale (Goeze, 1782) (Nematoda, Dioctophymidae) is presented. Mammals, including man, are the definitive hosts for this parasite. Several aspects of the infection with the parasite in mammals other than humans are critically evaluated: geographical distribution, host species recorded so far and the relative importance of the different hosts, location of parasites within the host, prevalence and intensity of the infection, diagnostic methods, pathology induced by the parasites, epidemiology and the methods of control and treatment. The authors provide an updated review about the infection, based on a extensive bibliographic search worldwide, and point out the most relevant aspects of the biology of the parasite as well as several research topics which need to be explored for a better understanding of the biology of this interesting and important parasitic nematode.     

儿童幽门螺杆菌感染

幽门螺杆菌感染不仅能引起胃炎、消化性溃疡,诱发胃癌等胃肠道的病变,还与许多胃肠外疾病密切相关,如果不经过特殊治疗将终生带菌,严重的影响小儿的生长发育和身心健康。这些问题引起了儿科医生和儿童保健医生的共同关注。儿童期既是幽门螺杆菌感染的特殊时期,也是控制感染的关键时期。本文将从小儿幽门螺杆菌国内外的感染状况、相关疾病、诊断方法、治疗及预防等几个方面综述如下。     

Ontological model of multi-agent Smart-system for predicting drug properties based on modified algorithms of artificial immune systems

Estimating HIV incidence is crucial for monitoring the epidemiology of this infection, planning screening and intervention campaigns, and evaluating the effectiveness of control measures. However, owing to the long and variable period from HIV infection to the development of AIDS and the introduction of highly active antiretroviral therapy, accurate incidence estimation remains a major challenge. Numerous estimation methods have been proposed in epidemiological modeling studies, and here we review commonly-used methods for estimation of HIV incidence. We review the essential data required for estimation along with the advantages and disadvantages, mathematical structures and likelihood derivations of these methods. The methods include the classical back-calculation method, the method based on CD4+ T-cell depletion, the use of HIV case reporting data, the use of cohort study data, the use of serial or cross-sectional prevalence data, and biomarker approach. By outlining the mechanistic features of each method, we provide guidance for planning incidence estimation efforts, which may depend on national or regional factors as well as the availability of epidemiological or laboratory datasets.     

Chicken anemia virus causes apoptosis of thymocytes after in vivo infection and of cell lines after in vitro infection.

After infection of 1-day-old chickens, chicken anemia virus (CAV) causes a complete depletion of the thymic cortex by day 14. Since cell death can be caused either by necrosis or by apoptosis, we investigated which type of cell death occurs after in vivo and in vitro infections with CAV. Using electron microscopy and biochemical methods, we demonstrated that CAV induces apoptosis of cortical thymocytes after in vivo infection and of lymphoblastoid cell lines after in vitro infection. At day 13 after in vivo infection, virus-like particles were detected in apoptotic bodies that were absorbed by epithelial cells. These results show that apoptosis, a phenomenon that has been observed for a few other viruses, is also an important phenomenon during the pathogenesis of CAV.     

Rapid early diagnosis of cytomegalovirus infection

Cytomegalovirus infection can now be diagnosed rapidly in the laboratory by methods which are reviewed here. Together with the clinical investigation of patients early in their infection before extensive tissue damage has occurred, these methods offer the option of considering therapeutic intervention in some patients.     

A comparison of eight methods for the dual-endpoint evaluation of efficacy in a proof-of-concept HIV vaccine trial

To support the design of the world's first proof-of-concept (POC) efficacy trial of a cell-mediated immunity-based HIV vaccine, we evaluate eight methods for testing the composite null hypothesis of no-vaccine effect on either the incidence of HIV infection or the viral load set point among those infected, relative to placebo. The first two methods use a single test applied to the actual values or ranks of a burden-of-illness (BOI) outcome that combines the infection and viral load endpoints. The other six methods combine separate tests for the two endpoints using unweighted or weighted versions of the two-part z, Simes', and Fisher's methods. Based on extensive simulations that were used to design the landmark POC trial, the BOI methods are shown to have generally low power for rejecting the composite null hypothesis (and hence advancing the vaccine to a subsequent large-scale efficacy trial). The unweighted Simes' and Fisher's combination methods perform best overall. Importantly, this conclusion holds even after the test for the viral load component is adjusted for bias that can be introduced by conditioning on a postrandomization event (HIV infection). The adjustment is derived using a selection bias model based on the principal stratification framework of causal inference.     

Multicenter evaluation of the novel enzyme immunoassay based on P1-enriched protein for the detection of Mycoplasma pneumoniae infection

The aim of the study was to evaluate new Mycoplasma pneumoniae IgG, IgA and IgM EIA methods based on the enrichment of P1-protein (ThermoLabsystems, Helsinki, Finland) (L) for the detection of acute infection. This evaluation was performed in two independent routine clinical microbiology laboratories. The first laboratory used samples preselected by IgG and IgM Platelia enzyme immunoassay (P) and the second used samples preseleced by Serion ELISA Classic M. pneumoniae IgG, IgM (V). The L method was also compared to the FDA approved method of ImmunoWell M. pneumoniae IgG and IgM (G). When the agreement of two methods was applied as a serologic criteria for an acute infection, the following ratios of acute to nonacute infection were calculated 32/86 (totally 118) in the first and 20/72 (totally 92) in the second laboratory. In the first laboratory, the corresponding ratios by methods were 35/83 (sensitivity 100%, specificity 96.5%), 31/87 (sensitivity 97%, specificity 100%), and 55/63 (sensitivity 100%, specificity 79%) for the L, P and G methods, respectively. In the second laboratory, the ratios were 21/71 (sensitivity 100%, specificity 99%), 16/76 (sensitivity 83%, specificity 100%), and 53/39 (sensitivity 100, specificity 69%) for the L, V and G methods, respectively. Taking into account that the tested sample material was preselected by the P and V methods, which may have introduced some bias in their favor, the newly developed L method utilizing P1-enriched protein was found reliable for serodiagnosis of acute M. pneumoniae infection. The method G was the least specific in detection of acute infection.     

Estimating Temporal Transmission Parameters from Infectious Disease Household Data, with Application to Taiwan SARS Data

Taking households having at least one infective as standard units and considering both a within-household infection rate and a global infection rate, we propose a Bayesian two level mixing S-I-R (susceptible-infective-removed) counting process model in which the transmission parameters may change over time and the parameters of interest are the within-household infection rate and the removal rate. Customized Markov chain Monte Carlo methods are developed for generating samples from the posterior distribution for inference purpose, based only on the removal times. The numerical performance of this method is examined in a simulation study. Applying this method to 2003 Taiwan SARS data, we find that the within-household infection rate decreases, the removal rate increases and their ratio is less than one and decreases significantly during the epidemic. This method allows the estimation of these parameters during the epidemic. For a rapidly transmitted disease, it provides a method to nearly real-time tracking of infection measures.     

A formula for the mean infection success per miracidium and a method of proving the homogeneous susceptibility of snail populations to trematode infection

A formula for computing the mean infection success per miracidium (“infection index”) is given for every permutation of the numbers of snails and miracidia in miracidial exposure experiments. This “infection index” allows the comparison of the results from quantitatively different exposure methods and may be important for characterizing special trematode- intermediate host systems. By means of the “infection index” it is shown that a laboratory population of Lymnaea stagnalis is homogeneous with regard to its susceptibility to Isthmiophora melis miracidia, i.e. that there is no appreciable rate of resistant individuals. Some experimental results which have been published by other authors and have been interpreted by them as indicating the resistance of a portion of snail populations can be numerically explained by means of the formula of the “infection index” and without necessarily assuming resistance.     

Polymerase chain reaction is superior to serology for the diagnosis of acute Mycoplasma pneumoniae infection and reveals a high rate of persistent infection

Background  

Diagnosis of Mycoplasma pneumoniae (MP) infection is traditionally based on serology, which may require more than two weeks for diagnostic antibodies to develop. PCR-based methods offer earlier diagnosis. During a community outbreak of MP infection, we compared semi-nested and real-time PCR of oropharyngeal swabs with serology for diagnosis of MP infection at different time points after disease onset. PCR-positive individuals were followed longitudinally to assess the persistence of MP DNA in throat secretions. We also studied carriage of MP among household contacts and school children.