Seasonal changes in infectivity of domestic populations of Triatoma infestans

This paper examines the infection rate of Trypanosoma cruzi in Triatoma infestans, the main vector of Chagas disease in Argentina and neighbouring countries. The study was carried out in 1986-1987 on 5 houses (ranchos) in the endemic area of central Argentina. Domestic T. infestans populations were sampled in each season with a constant capture effort (2.5 man-hours/house) using a chemical irritant. The rectal content of the bugs was examined for the presence of T. cruzi. The vector population density showed seasonal changes with highest values during the hot season (November-April). The percentage of infected bugs was higher in mid-spring (November) and autumn (April) than in winter (August) and early spring (October). The mean number of parasites (epimastigotes and trypomastigotes) per microliter of rectal material was very high during mid- and late spring (December). The percentage and number of metacyclic forms differed between seasons, reaching the highest values in late spring. The percentage of infected bugs in houses with children younger than 10 years old was higher than that in houses without children, during all the seasons. Late spring seemed to be the period when domestic populations of T. infestans had the highest vector potential.     

Comparison of techniques for detection of domestic infestations with Triatoma infestans in Brazil

The detection of infestations of Triatominae in houses in regions endemic for Chagas's disease is a criterion frequently used in the selection of areas, or of individual houses, for treatment in insecticide campaigns as well as in the evaluation of insecticide performance.Several different methods for detecting domestic infestations with Triatominae were compared: night capture, capture of live bugs with the aid of a flushing-out agent and use of card boxes of the Gómez-Núñez type. The flushing-out and Gómez-Núñez box methods were found to be equally sensitive, although each failed to detect some infestations which the other detected. The night capture method was slightly more sensitive but was found to be impractical for insecticide trials. Improvement to the flushing-out method, notably the introduction of a systematic search technique, made it much more sensitive than the Gómez-Núñez box method for heavily infested houses and for houses three months after insecticide treatment.Although the sensitivity of the Gómez-Núñez box method increases when the boxes are left in place for a long time, this also limits the value of the information obtained regarding the evaluation of insecticides. On the basis of the results presented, the flushing-out method using a systematic search of the house was found to be the most suitable sampling technique, but it is recognized that this method still has limitations.     

Density regulation of domestic populations of Triatoma infestans in Brazil

Twenty old houses in a rural area of central Brazil were sampled monthly for Triatoma infestans during 16 months. The samples indicated peak adult emergence between January and May, preceded by peak emergence of stage V, IV and III nymphs respectively. Stage I and II nymphs were rarely taken in the samples. A much smaller peak of adult emergence occurred in September; thus the two peaks of adult emergence during the year were consistent with the approximately six months duration of egg-to-adult development usually recorded in laboratory studies.During January, 1977, when the study began, all houses were searched for dead bugs, exuviae, eggs and eggshells. These samples were used to calculate stage mortalities, from which a simple life-table was constructed. These data were combined with laboratory data concerning stage development times and female longevity and fecundity. Sensitivity analysis of the life-table showed it to be most sensitive to small changes in daily mortality rate and total egg-to-adult development time.The data were used to advance an hypothesis that the size of domestic populations of T. infestans is mainly controlled by changes in the egg-to-adult development time and, to a lesser extent, by changes in female reproductivity. Both these factors are in turn controlled by the nutritional status of the bug population, which, if the supply of food, i.e. number of hosts, is constant, is dependent upon the density of the bug population. It is argued that this mechanism of density regulation functions within limits set by the prevailing ambient temperature.     

Fine-scale genetic structure of Triatoma infestans in the Argentine Chaco

The patterns of genetic structure in natural populations provide essential information for the improvement of pest management strategies including those targeting arthropod vectors of human diseases. We analyzed the patterns of fine-scale genetic structure in Triatoma infestans in a well-defined rural area close to Pampa del Indio, in the Argentine Arid-Humid Chaco transition, where a longitudinal study on house infestation and wing geometric morphometry is being conducted since 2007. A total of 228 insects collected in 16 domestic and peridomestic sites from two rural communities was genotyped for 10 microsatellite loci and analyzed. We did not find departures from Hardy–Weinberg expectations in collection sites, with three exceptions probably due to null alleles and substructuring. Domestic sites were more variable than peridomestic sites suggesting the presence of older bug populations in domestic sites or higher effective population sizes. Significant genetic structure was detected using F-statistics, a discriminant analysis of principal components and Bayesian clustering algorithms in an area of only 6.32 km². Microsatellite markers detected population structuring at a finer geographic scale (180–6300 m) than a previous study based on wing geometric morphometry (>4000 m). The spatial distribution of genetic variability was more properly explained by a hierarchical island than by an isolation-by-distance model. This study illustrates that, despite more than a decade without vector control interventions enhancing differentiation, genetic structure can be detected in T. infestans populations, particularly applying spatial information. This supports the potential of genetic studies to provide key information for hypothesis testing of the origins of house reinfestation.     

艾滋病患者粪便HIV-1 RNA的研究

目的研究艾滋病患者粪便HIV-1 RNA,分析其与血液HIV-1 RNA的相关性,并比较它们在治疗(抗反转录病毒治疗)和未治疗(未抗反转录病毒)患者中的区别。方法收集32例艾滋病患者粪便和血液标本,两者一一对应,根据临床资料将其分为治疗组和未治疗组,分析粪便和血液HIV-1 RNA的组内相关性和组间相关性。结果2组都表现出粪便HIV-1 RNA检出率低于血液且粪便中病毒载量低于血液,且2组间粪便和血液阳性率对比差异均有统计学意义(P<0.001),其中未治疗组粪便和血液的HIV-1 RNA阳性率较高。结论粪便中可以检测到HIV-1 RNA,其在未经过抗反转录病毒的患者中易检出,同一患者粪便中的HIV-1病毒载量比血液低。     

C-反应蛋白在HIV/AIDS的表达及其相关性研究

目的探讨在抗病毒治疗前血清C-反应蛋白(CRP)在人类免疫缺陷病毒感染者/获得性免疫缺陷综合征患者(HIV/AIDS)中的表达及其与WHO临床分期的关系,为研究HIV疾病进展和预后提供理论依据。方法分别测定173例HIV/AIDS及24名健康对照组血清CRP水平,对WHO临床各期及健康对照组的CRP水平进行比较,分析CRP水平与WHO临床分期的相关性。结果 WHO临床I、Ⅱ、Ⅲ、Ⅳ期、健康对照组CRP水平分别为0.05、0.14、3.85、6.10、0mg/L,组间差异有统计学意义(P<0.05);WHO临床Ⅱ、Ⅲ、Ⅳ期CRP水平均分别高于健康对照组(P<0.05),WHO临床Ⅲ、ⅣCRP水平分别高于Ⅱ、Ⅰ期(P<0.05),WHO临床Ⅰ期CRP水平和Ⅱ期差异无统计学意义,WHO临床Ⅲ期CRP水平和Ⅳ期差异无统计学意义;CRP的表达与性别、年龄、CD4细胞、WHO临床分期、体质量指数、血清白蛋白、血红蛋白均相关(P<0.05);调整年龄、性别后,CRP同CD4细胞、体质量指数、血清白蛋白、血红蛋白呈负相关(P<0.05),同WHO临床分期呈正相关(P<0.05)。结论 CRP在HIV/AIDS中呈高表达,与疾病进展呈正相关。     

HIV/AIDS患者的心理需求调查

目的 了解HIV／AIDS患者的心理需求。方法 对我国4个省111例HIV／AIDS进行流行病学问卷调查和个人深入访谈。结果 大部分感染者都表现出对结果的不相信，在知道感染后大部分感染者都选择不告诉其他人。对于是否愿意和其他感染者进行交流。在因吸毒和血液途径的感染者中均有较高的比例，分别是75．56％和87．10％，而且其中94．29％和100％的人将面对面交流作为首选。结论 HIV／AIDS患者承受的心理压力巨大，应采取有效措施加以改善。     

Nutritional status in patients with HIV infection and AIDS

The aim of this study was to evaluate the nutritional status of adults with HIV infection or with AIDS through the use of biochemical parameters. The study was performed on 43 patients (19 HIV+ and 24 AIDS patients), between 26 and 44 years of age, from low and medium socioeconomic status, with access to health care services; 35 patients were under highly active antiretroviral therapy (HAART) treatment. Body weight and height were determined, and the Body Mass Index calculated (kg/m2). Blood samples were collected from fasting patients. Plasma cholesterol (total, HDL and LDL), triacylglycerol, total protein, apolipoproteins A-I and B, albumin, transthyretin, retinol binding protein, and ceruloplasmin concentrations were determined. Plasma levels of zinc, copper, and selenium were determined in a haemolysis-free sample by flame atomic absorption spectrometry. Statistical analyses were performed with the Student's t-test. AIDS patients showed changes in biochemical parameters, particularly an increase in fibrinogen and a trend to decreased transthyretin levels. These findings stress the importance of the inclusion of functional biochemical parameters in the periodic evaluation of these patients. This would allow an early assessment of the need for appropriate nutritional support, implemented along with the specific retroviral treatment. This would aim at delaying the progression of the disease, and might improve the prospects of survival and quality of life.     

Time from infection with HIV to onset of AIDS in patients with haemophilia in the UK

The two-stage parametric regression model of Brookmeyer and Goedert has been adapted and fitted to data on the development of AIDS in haemophiliacs in the UK who are seropositive for HIV. The risk of developing AIDS by a given time following seroconversion increases with increasing age at seroconversion. It is likely that the risk increases smoothly with age, although the data have been analysed in three age categories, and it is estimated that by seven years after seroconversion 6 per cent of patients aged under 25 at seroconversion, 20 per cent of those aged 25-44 and 34 per cent of those aged 45 or more have developed AIDS. For a given age at seroconversion the annual risk of developing AIDS increases with increasing time after seroconversion, and at seven years the annual risks of developing AIDS during the next year in the three age groups are estimated to be 2 per cent for those aged less than 25 at seroconversion, and 10 and 11 per cent respectively for those aged 25-44 and 45 or more.     

2013-2017年贵州省艾滋病患者HIV亚型分布

目的  调查贵州省接受抗逆转录病毒治疗（antiretroviral therapy,ART）的人类免疫缺陷病毒/艾滋病（human immunodeficiency virus/acquired immune deficiency syndrome,HIV/AIDS）患者的HIV亚型分布特征,为艾滋病防治提供参考。 方法  采用方便抽样策略,收集贵州省2013-2017年间8 583份抗病毒治疗半年以上的在治艾滋病患者血浆,采用面对面问卷调查、HIV检测等横断面调查。 结果  其中有1 511例HIV病毒抑制失败（病毒载量,viral load,VL>1 000 copies/ml）,成功对1 410例（93.31%）HIV抑制失败患者的HIV pol基因进行基因分型。结果显示,51.42%为CRF01_AE基因型,26.67%为CRF07_BC基因型,16.1%为CRF08_BC基因型。 结论  通过对贵州省近年来HIV流行亚型和主要传播途径的变化分析,提示HIV基因突变引起亚型的改变应先于HIV主要传播途径的改变,及时监测HIV亚型变化可作为防治艾滋病的主要依据之一。     

Utilities derived from visual analog scale scores in patients with HIV/AIDS.

BACKGROUND: Visual analog scale (VAS) scores are used as global quality-of-life indicators and, unlike true utilities (which assess the desirability of health states v. an external metric), are often collected in HIV-related clinical trials. The purpose of this study was to derive and evaluate transformations relating aggregate VAS scores to utilities for current health in patients with HIV/AIDS. METHODS: HIV-specific transformations were developed using linear and nonlinear regression to attain models that best fit mean VAS and standard gamble (SG) utility values directly derived from 299 patients with HIV/AIDS participating in a multicenter study of health values. The authors evaluated the transformations using VAS and SG utility values derived directly from patients in other HIV/AIDS studies. Derived transformations were also compared with published transformations. RESULTS: A simple linear transformation was derived (u = 0.44v + 0.49), as was the exponent for a curvilinear model (u = 1 - [1 - v]1.6), where u = the sample mean utility and v the sample mean VAS score. The curvilinear transformation predicted values within 0.10 of the actual SG utility in 5 of 8 estimates and within 0.05 in 3 of 8 estimates (absolute error ranged from -0.01 to +0.21). The linear transformation performed somewhat better, predicting within 0.10 of the actual SG value in 6 of 8 cases and within 0.05 in 5 of 8 estimates (absolute error ranged from -0.05 to +0.13). An alternative linear model (u = v + 0.018) derived from the literature performed similarly to our linear model (7 of 8 predictions within 0.10, 1 of 8 estimates within 0.05, and absolute error ranging from -0.15 to +0.10), whereas an alternative published curvilinear model (u = 1 - [1 - v]2.3) performed the least well (2 of 8 estimates within 0.10 of the actual values and no estimates within 0.05). CONCLUSIONS: Predicted utilities are a reasonable alternative for use in HIV/AIDS decision analyses and cost-effectiveness analyses. Linear transformations performed better than curvilinear transformations in this context and can be used to convert aggregate VAS scores to aggregate SG values in large HIV/AIDS studies that collect VAS data but not utilities.     

24例HIV/AIDS流行病学及临床研究

江苏省系艾滋病低发区,艾滋病报道较少,但近年来该病有较迅速上升的势头,现就我院自2001年11月以来收治的24例艾滋病病毒感染者或病人(HIV／AIDS)的流行病学及临床资料报告如下。     

HIV and AIDS, stigma and AIDS support groups: Perspectives from women living with HIV and AIDS in central Thailand

In this paper, community attitudes toward women living with HIV and AIDS at the present time from the perspectives of women in Thailand are examined. We also look at strategies women use in order to deal with any stigma and discrimination that they may feel or experience in the community. The paper is based on our larger study of the experiences of women living with HIV and AIDS and their participation in clinical trials. In late 2007 and early 2008 we carried out a number of in-depth interviews with women living with HIV and AIDS in central Thailand. We find that women living with HIV and AIDS still deal with stigma and discrimination in their everyday life. However, from the women's narratives, we also find more positive attitudes from local communities. Some women deal with stigma and discrimination by joining and participating in HIV and AIDS support groups that have emerged in response to the AIDS epidemic in Thailand. We argue that women are not passive victims, but that they act in their own agencies to counteract any negativity they might encounter.     

144例HIV感染者及AIDS患者的感知歧视状态调查

目的 调查男男性行为者（Men who Have Sex with Men, MSM）和有偿献血者中的HIV感染者及艾滋病患者（People Living with HIV/AIDS, PLWHA）的感知歧视状态。方法 采用便利抽样方法,调查湖北省武汉市及随州市HIV感染者及艾滋病患者144例,使用Berger HIV感知歧视量表测量其感知歧视水平。结果 MSM人群的总分和4个维度得分均高于有偿献血人群。对于有偿献血者中的PLWHA,中年比老年的感知歧视水平更高（β=-23.1222,P＜0.0001）;对于MSM中的PLWHA,有固定收入者比无固定收入者的歧视感知更高(β=24.4629,P=0.0484)。结论 不同类型HIV感染者及艾滋病患者的感知歧视水平差异明显。在提供艾滋病行为干预和临床治疗等服务时,对于感知歧视敏感的患者,更要注重服务方式,避免患者对这些服务产生排斥。     

Temporal variations of fluctuating asymmetry in wing size and shape of Triatoma infestans populations from northwest Argentina

Environmentally-induced developmental instability has frequently been assessed using fluctuating asymmetry (FA) methods. For Triatoma infestans, the major vector of Chagas disease, the combined effects of host-feeding sources and habitats affected wing developmental instability depending on sex in Figueroa villages, northwest Argentina. Here we investigated whether habitat, sex, season/year and insecticide applications affected wing developmental instability in T. infestans populations from Amamá and other rural villages of northwest Argentina over a four-year period. We measured the occurrence and amount of wing size and shape FA in 423 adult triatomines collected in domiciles, goat corrals, pig corrals, storerooms and wood piles. Significant wing size and wing shape FA occurred in females and males from all habitats as determined by two-way mixed ANOVA and Procrustes ANOVA, respectively. For wing size and shape, the highest corrected indices of FA (FAI) for females occurred in wood piles, goat corrals and domiciles in late summer or early autumn, whereas for males, the largest FAIs consistently appeared in domiciles and storerooms. Wing size FAIs were significantly higher in recently infested goat corrals rather than in persistently infested goat corrals. The follow-up of four infested peridomestic sites showed that FA patterns were not stable over time or sites. Temporal variation of FA among habitats appears to be modified by the history of insecticide spraying, either through direct effects on insect development or through indirect effects related to flight dispersal and house invasion. Whether FA may provide another marker to identify the sources of reinfestant triatomines requires further investigation.