Lymnic molluscs from an Alto Araguaia area (Brazil)]

An analysis was carried out to determine the natural population of freshwater molluscs from 5 municipalities within the area of influence of the Couto Magalh?es hydroelectric project. These municipalities cover a large area of the State of Goiás and Mato Grosso do Sul (Brazil). In this study 624 molluscs of the following species were examined: Drepanotrema anatinum, D. lucidum, D. depressissimum, Biomphalaria straminea, D. schrammi, Physa marmorata, Lymnaea columella, Pomacea and Eupera. One to their importance in public health, the discovery of Biomphalaria straminea and Lymnaea columella, intermediate hosts, respectively, of Shistosoma mansoni and Fasciola hepatica, deserves special mention.     

Miracidial attraction by Biomphalaria tenagophila genetically selected for susceptibility]

The attraction of Schistosoma mansoni miracidea by snails genetically selected for susceptibility to infection is considered. Miracidea were exposed to snails or to snail conditioned water in a specially devised three-chamber glass apparatus. Ten miracidea were used for each test and were deposited in the middle chamber (a passage); after 15 minutes, them in each of the number of the three chambers were recorded. In one of the chambers, chosen randomly at each trial, either snails or SCW were used. The snails and the SCW were chosen from either selected snails (highly susceptible) or unselected. The miracidea were of two groups: they came either from susceptible snails in previous generation or were of unselected traits. The results show that only snail generation has importance for the attraction: selected molluscs of susceptible traits do attract the miracidea more.     

Schistosomiasis mansoni and distribution of freshwater mollusks in natural bodies of water in Niterói,Rio de Janeiro State,Brazil

The authors report on the distribution of freshwater mollusks in Niterói, Rio de Janeiro State, Brazil, and notification of schistosomiasis cases in this municipality from 1995 to 2000. All breeding sites favorable to freshwater mollusks were surveyed, showing the following species: Antillorbis nordestensis (Lucena, 1954), Biomphalaria straminea (Dunker, 1848), Biomphalaria tenagophila (Orbigny, 1835), Drepanotrema anatinum (Orbigny, 1835), Lymnaea columella Say, 1817, Melanoides tuberculatus (Müller, 1774), Physa cubensis Pfeiffer, 1839, Physa marmorata Guilding, 1828, and Pomacea sordida (Swainson, 1823). Some 3,691 specimens of snail hosts for Schistosoma mansoni Sambon, 1907 were examined by exposure to artificial light and crushing. No S. mansoni cercariae were found, although other types of cercariae were observed.     

蛋白质分子对日本血吸虫毛蚴趋向作用的观察

目的采用自制的钉螺(Oncomelania hupensis)模拟装置法对比法,初步观察蛋白质对日本血吸虫毛蚴(Schistosoma japanicummiracidia)的趋向作用及其在"模拟钉螺"中的应用。方法采用自制的钉螺模拟装置——玻璃盲管,取钉螺模拟装置四支,标号为A、B、C、D。A管装满去氯水,B管装满螺SCW液,C管装满去离子的SCW液,D管装满去离子去蛋白质的SCW液。在玻璃平底圆盘中注入刚孵出的毛蚴悬液200 ml(毛蚴密度约20个/ml),静置3 min,让毛蚴在容器内自由活动并均匀分布。然后将钉螺模拟装置同时放入玻璃圆盘中,5 min后将装置同时取出,进行观察和计数比较。结果 B管与C管毛蚴数明显高于A管,且差异有统计学意义(P0.05);C管与D管差异无统计学意义(P0.05)。结论蛋白质分子对毛蚴的吸引作用很小,没有明显的排斥作用,也没有明显的吸引作用,在钉螺吸引毛蚴的理论方面可以不考虑蛋白质分子的趋向影响。     

Low level of bacterial contamination of mist tents used in home treatment of cystic fibrosis patients

Mist tents are recommended by the Stockholm cystic fibrosis (CF) centre for small children with CF. Daily disinfection of some parts of the tent with 2% acetic acid is recommended, and for other parts boiling water followed by air-drying without rinsing. The plastic tent is discarded each day. We have studied whether these prescribed routines are followed by the patients and whether they are sufficient to prevent bacterial contamination. The mist tent equipment of 20 CF patients (mean age 7 years, range 1-15 years), two of whom were chronically colonized with Pseudomonas aeruginosa, were investigated. All patients were visited at home in the morning after 6-12 hours aerosol therapy. Liquid from the nebulizing chambers and swabs from the aerosol tube were examined by culture on four different media. Seventeen of 20 patients claimed that they cleaned and disinfected the tubes every day, two patients every other day and one once a week. Seventeen of 19 claimed they cleaned and disinfected the chambers daily, one once a week and, one twice a week. No or insignificant growth was found in 16/20 aerosol tubes: moulds in three, Pseudomonas species in one. Twelve of 19 chambers showed no or insignificant growth: moulds or yeasts were present in three and Pseudomonas sp. in four. In four of the seven patients moulds or yeasts and/or Pseudomonas sp. grew both from chambers and from aerosol tubes; in the remaining three only from chambers. None of these seven patients had followed our prescribed cleaning and disinfection recommendations, the other 13 claimed they had. Of the patients whose equipment yielded Pseudomonas sp, none was colonized with these strains, although one had P. aeruginosa. We conclude that our disinfection recommendations are adequate when followed. However, our disinfection recommendations concerning the nebulizing chamber had not been followed satisfactorily. The different forms of non-compliance would not have been detected without a home visit, emphasizing the importance of such visits. The importance of drying the equipment and of using the correct concentration of acetic acid is stressed.     

Host-parasite relationship of Bulinus truncatus and Schistosoma haematobium in Iran. 2. Effect of exposure dosage of miracidia on the biology of the snail host and the development of the parasites

Laboratory experiments were carried out to study the development of Bulinus truncatus and the larval stages of Schistosoma haematobium after the snails had been exposed to various numbers of miracidia. The results showed: (1) that in the cercarial-incubation period the growth and survival rate of snails was not influenced by the development of the larval stages of S. haematobium, but that in the cercaria-shedding period the life-span of the infected snails was shorter than that of the non-infected controls; (2) that reduction of oviposition was proportional to the exposure of miracidia; (3) that the length of the cercarial-incubation period in snails was inversely proportional to the exposure number of miracidia; (4) that all the snails exposed to 20 miracidia (the maximum exposure number used) shed cercariae; (5) that snails exposed to one miracidium each shed fewer cercariae than those exposed to two or more miracidia each; and (6) that the peak of cercaria-shedding occurred 40 to 90 days after the shedding had started, varying in different groups.     

Acute toxicity of cadmium, lead, zinc, and their mixtures to stream-resident fish and invertebrates

The authors conducted 150 tests of the acute toxicity of resident fish and invertebrates to Cd, Pb, and Zn, separately and in mixtures, in waters from the South Fork Coeur d'Alene River watershed, Idaho, USA. Field-collected shorthead sculpin (Cottus confusus), westslope cutthroat trout (Oncorhynchus clarkii lewisi), two mayflies (Baetis tricaudatus and Rhithrogena sp.), a stonefly (Sweltsa sp.), a caddisfly (Arctopsyche sp.), a snail (Gyraulus sp.), and hatchery rainbow trout (Oncorhynchus mykiss), were tested with all three metals. With Pb, the mayflies (Drunella sp., Epeorus sp., and Leptophlebiidae), a Simuliidae black fly, a Chironomidae midge, a Tipula sp. crane fly, a Dytiscidae beetle, and another snail (Physa sp.), were also tested. Adult westslope cutthroat trout were captured to establish a broodstock to provide fry of known ages for testing. With Cd, the range of 96-h median effect concentrations (EC50s) was 0.4 to >5,329 μg/L, and the relative resistances of taxa were westslope cutthroat trout ≈ rainbow trout ≈ sculpin < other taxa; with Pb, EC50s ranged from 47 to 3,323 μg/L, with westslope cutthroat trout < rainbow trout < other taxa; and with Zn, EC50s ranged from 21 to 3,704 μg/L, with rainbow trout < westslope cutthroat trout ≈ sculpin < other taxa. With swim-up trout fry, a pattern of decreasing resistance with increasing fish size was observed. In metal mixtures, the toxicities of the three metals were less than additive on a concentration-addition basis.     

The incidence of disability pensions and mortality among semi-skilled construction workers in Copenhagen. A retrospective cohort study with two control groups

The aim of the present study was to discover whether the incidence of disability pensions and mortality was higher amongst semi-skilled construction workers (SCW) in Copenhagen than in two control groups from the same geographic area. The population investigated consisted of a fixed cohort of 3537 SCW from Copenhagen as per 1/5/1975. The two control groups comprised 3818 Copenhagen members of the Warehouse Workers' union and a group of Copenhagen members of the Semi-skilled Worker's Union age-matched to the SCW cohort, both as per 1/5/75. Up to 31/12/79, a total of 102 SCW were granted disability pensions, compared with 89 and 77 in the two control groups respectively, i.e. a significantly higher frequency of award of disability pension among SCW than among warehouse workers (p less than 0.05). This was due especially to a higher frequency of disability pensions granted because of musculoskeletal diseases and cancer in SCW. The number of deaths was recorded from 1/5/75 to 30/11/78. No differences in overall mortality were found among the three groups, although slightly fewer deaths from lung cancer and ischaemic heart diseases and more suicides were observed among the construction workers. Selection bias and the effect of the working environment are discussed against the background of a concurrent investigation of the state of health and working conditions of SCW.     

Long-term controlled field experiment on the competition between two species of Biomphalaria (Mollusca, Basommatophora), the snail vectors of Schistosoma mansoni in Northeastern Brazil

A long-term controlled field experiment on the interactions of the populations of Biomphalaria glabrata (target population) and B. straminea (competitor) was carried out in the county of Alhandra, state of Paraíba, Brazil, during the period 1980 through 1989. Results obtained in the current paper show that the snail B. straminea has strong competitive advantages over B. glabrata. In six out of nine streams the native population of B. glabrata were totally excluded and replaced by B. straminea. There is evidence showing that seasonal dryness has marked influence on the phenomenon studied in this paper. In all the streams were B. straminea already predominated, return of B. glabrata was never observed.     

Host-parasite relationship of Bulinus truncatus and Schistosoma haematobium in Iran. 3. Effect of water temperature on the ability of miracidia to infect snails

Laboratory studies were made in Iran to test the effect of water temperature on the ability of the miracidia of S. haematobium to penetrate B. truncatus. Snails three to four weeks old were exposed to two miracidia each for two hours at nine water temperatures ranging from 10°C to 38°C. After exposure, all the snails were kept in aquaria at room temperature. The cercaria-positive rates of these nine groups of snails showed that the optimum exposure temperature was in the range 20°C-30°C. The infection rate was low at temperatures outside this range. It is concluded that the optimum transmission seasons in bilharziasis-endemic areas in Iran are spring and autumn but that transmission still occurs in hot summer and cold winter months although to a much smaller extent.     

Discriminant analysis of free fatty acids of some Egyptian snails as a step for schistosomiasis control: new trends

Schistosomiasis is still the most common occupational health problem of rural workers in Egypt. The use of molluscicides, either chemical or biological, and environmental changing are the most successful methods of snail control. The new trend in Schistosoma control programs is to study the ecological factors that attract miracidium Schistosoma specific snails, to emphasizing to find out new environmental safe control methods. Since Schistosoma worms do not make fatty acids de novo, they require host lipids for survival and to complete their life cycle. Discriminate analysis of the estimated free fatty acids was done in this study in Biomphalaria alexandrina, Biomphalaria glabrata, and Bulinus truncatus, viz. Lymnaea truncatula and Physa acuta (Schistosoma intermediate and non-intermediate respectively). With the objective of determination of the biochemical difference that attract the infestation of Schistosoma miracidium to the target snails, as a step of the new control trends. Caprylic acid (C8:0), and Oleic acid (C18:1) are significantly lower in the tissues of Schistosoma intermediate snails compared to the non-intermediate snails. While, Capric acid (C10:0), Margaric acid (C17:0), and Lenoleic acid (C18:2) of the intermediate snails are significantly higher than that of non-intermediate snails. The percent of correct medical classification of snails are more than 80% according to Caprylic acid, Margaric acid, and Lenoleic acid, the other 15 fatty acids are less than 80%. These three free fatty acids could be chemoattractive of Schistosoma miracidium, and could be used as safe environmental control compounds, which needs further research.     

Occurrence of schistosomiasis mansoni vectors on the Northern coast of the State of São Paulo, Brazil

This article comments on the detection of Biomphalaria tenagophila (d'Orbigny, 1835) infected with Schistosoma mansoni Sambon, 1907 in Caraguatatuba and the introduction of Biomphalaria straminea (Dunker, 1848) in Ilha Bela, two municipalities on the Northern coast of the State of S?o Paulo, Brazil. Infected snails were collected from a ditch located in the Olaria district. B. straminea and B. tenagophila were living in syntopy in a stream situated in Barra Velha. Such epidemiological findings indicate the risk of spread of schistosomiasis mansoni in the region, a consequence of inadequate basic sanitation.     

Assessment of the potential of competitor snails and African catfish (Clarias gariepinus) as biocontrol agents against snail hosts transmitting schistosomiasis

The objective of this study was to assess the potential of the snails Physa acuta and Melanoides tuberculata and the African catfish Clarias gariepinus as biological control agents against the Schistosoma mansoni intermediate host Biomphalaria pfeifferi under laboratory conditions. Groups of five target and five competitor snails were raised together in experimental aquaria and same number in separate aquaria as controls. Shell size, number of eggs and mortality rate were recorded for twelve consecutive weeks. The stocking density for C. gariepinus was one fish per aquarium. Fish were provided with adequate or inadequate supplementary food and fifteen B. pfeifferi were added to each aquarium. The snails and their eggs were counted daily. Significant differences in shell growth and fecundity were noted between B. pfeifferi and M. tuberculata. Physa acuta was noted to be voracious in food consumption. Snail consumption was faster by fish provided with inadequate supplementary food. Based on the present findings, it is suggested that the two competitor snails and African catfish could be used as biological control agents against B. pfeifferi. Nevertheless, the susceptibility of the competitor snails to other trematodes in Ethiopia must first be ruled out before introducing these snails into new habitats. Follow-up field observation and rigorous laboratory studies remain areas for further research.     

Feasibility of single-isocenter,multi-arc non-coplanar volumetric modulated arc therapy for multiple brain tumors using a linear accelerator with a 160-leaf multileaf collimator: a phantom study

The feasibility of single isocenter, multi-arc non-coplanar volumetric modulated arc therapy (VMAT) for multiple brain tumors was studied using an Elekta Synergy linear accelerator with an Agility multileaf collimator and a Monaco treatment planning system. Two VMAT radiosurgery plans consisting of a full arc and three half arcs were created with a prescribed dose of 20 Gy in a single fraction. After dose delivery to a phantom, ionization chambers and radiochromic films were used for dose measurement. The first VMAT radiosurgery plan had nine targets inside the phantom, and the doses were measured by the chambers at two different points and by the films on three sagittal and three coronal planes. The differences between the calculated dose and the dose measured by a Farmer ionization chamber and a pinpoint ionization chamber were <1.00% and <2.30%, respectively, and the average pass rates of gamma indices among the six planes under each of 3%/3 mm and 2%/2 mm criteria were 98.6% and 92.6%, respectively. The second VMAT radiosurgery plan was based on a clinical 14 brain metastases. Differences between calculated and film-measured doses were evaluated on two sagittal planes. The average pass rates of the gamma indices on the planes under each of 3%/3 mm and 2%/2 mm criteria were 97.8% and 88.8%, respectively. It was confirmed that single-isocenter, non-coplanar multi-arc VMAT radiosurgery for multiple brain metastases was feasible using Elekta Synergy with Agility and Monaco treatment planning systems. It was further shown that film dosimetry was accurately performed for a dose of up to nearly 25 Gy.     

The bioecology of snail vectors for schitosomiasis in Brazil

This paper describes the ecology of two species of Biomphalaria: B. glabrata and B. straminea. These species have been intensively studied in Brazil and in other countries since the 1950s. The literature in this area can be broadly subdivided into three categories, linked to three distinct historical periods: 1) an accumulated store of early studies carried out in the laboratory and in the field; 2) the development of quantitative ecological models; and 3) the development of an alternative methodology for breeding snails under seminatural conditions.     

滑车上动脉蒂额部三叶瓣修复鼻尖鼻翼及鼻小柱缺损的疗效分析

目的：探讨应用滑车上动脉蒂额部三叶瓣同时修复鼻尖鼻翼及鼻小柱缺损的临床疗效及治疗经验。方法：选取2008年9月-2013年2月本院收治的5例同时存在鼻尖鼻翼及鼻小柱缺损的患者,均采用滑车上动脉蒂额部三叶瓣修复。手术分2期进行：Ⅰ期行皮肤扩张器置入额部帽状腱膜及额肌下扩张充足的皮肤软组织;Ⅱ期设计滑车上动脉额部三叶瓣转移修复鼻尖鼻翼及鼻小柱缺损。结果：本组5例滑车上动脉蒂额部三叶瓣全部存活,随访4-12个月,平均随访8个月,鼻外形、功能良好,皮瓣色泽、质地与周围皮肤基本一致。结论：滑车上动脉蒂额部三叶瓣能同时修复鼻尖鼻翼及鼻小柱缺损,修复后鼻外形、功能良好,疗效可靠,是治疗同时存在鼻尖鼻翼及鼻小柱缺损较理想的方法。     

The role of hygienic bathing after defecation in the transmission of Schistosoma mansoni

Transmission of Schistosoma mansoni depends on fecal eggs reaching water, but the way this happens is poorly understood. We studied the role of hygienic bathing after defecation in the contamination of water with S. mansoni eggs. Individuals in an endemic community in Northern Senegal (n=991) were examined for S. mansoni infection and a random sample (22%) was interviewed about stool disposal practices and hygienic behavior. We assessed the presence and viability of S. mansoni eggs adhering to the peri-anal region of 13 infected volunteers, by counting the miracidia in the water they had used for hygienic washing; for 10 of them (77%) miracidia were demonstrated. From the population infection distribution, average number of defecations per day, proportion of individuals bathing after defecation, and association between miracidial counts and infection intensity, we calculated a daily population miracidial output of approximately 30,000 through hygienic bathing. For comparison, one complete stool reaching the water was calculated to yield approximately 2500 miracidia. Thus, 12 individuals in this population should defecate into the water every day to produce the same number of miracidia as through hygienic bathing. Our results suggest a major role of hygienic bathing after defecation in the transmission of S. mansoni.     

Developing a novel method to analyse Gafchromic EBT2 films in intensity modulated radiation therapy quality assurance

Recently individual intensity modulated radiation therapy quality assurances (IMRT QA) have been more and more performed with Gafchromic? EBT series films processed in red–green–blue (R–G–B) channel due to their extremely high spatial resolution. However, the efficiency of this method is relatively low, as for each box of film, a calibration curve must be established prior to the film being used for measurement. In this study, the authors find a novel method to process the Gafchromic? EBT series, that is, to use the 16-bit greyscale channel to process the exposed film rather than the conventional 48-bit R–G–B channel, which greatly increases the efficiency and even accuracy of the whole IMRT procedure. The main advantage is that when processed in greyscale channel, the Gafchromic? EBT2 films exhibits a linear relationship between the net pixel value and the dose delivered. This linear relationship firstly reduces the error in calibration-curve fitting, and secondly saves the need of establishing a calibration curve for each box of films if it is only to be used for relative measurements. Clinical testing for this novel method was carried out in two radiation therapy centres that involved a total of 743 IMRT cases, and 740 cases passed the 3 mm 3 % gamma analysis criteria. The cases were also tested with small ionization chambers (cc-13) and the results were convincing. Consequently the authors recommend the use of this novel method to improve the accuracy and efficiency of individual IMRT QA procedure using Gafchromic EBT2 films.     

A microbiological study of bottled mineral water marketed in Ludhiana

The microbiological quality of bottled mineral water marketed in Ludhiana was examined, Twenty three brands were analyzed for presumptive coliform count by multiple tube tests, and E. coli count was confirmed by Eijkman test. Bacterial and fungal loads were tested by membrane filtration test. Out of 23 only one sample (4.4%) showed the presumptive coliform count to be 460 most probable number (MPN)l 1 00ml,and 1 was found to be positive when tested by Eijkman test for Ecoli. In the membrane filtration test three samples (13%) showed more than two types of bacteria. Different types of bacteria isolated included Bacillus sp (19/23). Pseudomonas spp (13123), Ecoli, Klebsiella sp and S.albus one each Fungi was isolated from five of twenty three. (22%) samples. Only one brand of mineral water was unfit for human consumption. The rest of the samples were contaminated with non pathogenic flora.     

Diptera of sanitary importance associated with composting of biosolids in Argentina

OBJECTIVE: Odorous compounds produced at the biosolids composting plant in Bariloche (NW Patagonia) attract a variety of insects, mainly belonging to the order Diptera. In order to characterize these flies, collected specimens were taxonomically identified, their community characteristics were described and their sanitary and synanthropic importance and autochthonous or introduced character were determined. METHODS: Sampling was performed from October 1999 until March 2000. Adults were collected using an entomological net, and larvae and puparia were obtained from the composting material and incubated to obtain adults. Richness, abundance and sex ratio were calculated. RESULTS: A total of 9 taxa of Diptera were identified: Sarconesia chlorogaster, Phaenicia sericata, Calliphora vicina, Cochliomya macellaria, Ophyra sp, Muscina stabulans, Musca domestica, Sarcophaga sp and Fannia sp. Specimens of Anthomyiidae, Acaliptratae and one larva of Eristalis tenax were also found. Ophyra sp. was the most abundant taxa. All the captured Diptera belonged to introduced taxa. Most of them are considered to be eusynanthropic and/or hemisynanthropic and have sanitary importance as they may cause myiasis and pseudomyiasis. The high number of females registered and the finding of immature stages indicated that flies can develop their complete life cycle on biosolid composting windrows. CONCLUSIONS: The characterization of flies obtained in this study may be useful for defining locations of urban or semi-urban composting facilities. It also highlights the importance of sanitary precautions at such plants.