Schistosomiasis: new occurrence of Biomphalaria straminea in Belo Horizonte, Minas Gerais

In Belo Horizonte, Minas Gerais, Brazil, the snail Biomphalaria straminea was found in the Pampulha region. Recently the snail was found in ditches in the old Santa Lúcia Reservoir, a now-extinct focus of schistosomiasis transmission by B. glabrata. The snails were collected and examined to verify whether they were naturally infected with Schistosoma mansoni. Negative specimens were used for breeding or infection with the LE strain of S. mansoni from the laboratory and another strain obtained from eggs found in the feces of a schoolchild (VGS) from Belo Horizonte. Among the 1890 snails collected from 1994 to 1995, none were infected with S. mansoni. Among 87 snails collected and exposed to the LE strain, 9 (10.3%) shed cercariae; among 83 snails from F1, and exposed to LE, 10 (12.0%) shed cercariae. Among 88 snails exposed to VGS, 10 (11.3%) shed cercariae. In Belo Horizonte, schistosomiasis is transmitted by B. glabrata and B. tenagophila. However, currently there exists the risk of appearance of a focus in which B. straminea could be the host if prophylactic measures are not taken by the authorities responsible for the construction of a park and lake at that site.     

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.     

A malacological survey in city parks in Belo Horizonte, Minas Gerais, Brasil

The Greater Metropolitan Area of Belo Horizonte currently contains 18 city parks (also known as "ecological parks") with various bodies of water (lakes, springs, streams, etc). Initial research in 17 of these parks showed the occurrence of intermediate mollusk hosts for Schistosoma mansoni in at least 4. Monthly captures done from August 1994 to February 1996 showed the following results for these planorbids: Julien Rien Park: 1,145 specimens of Biomphalaria glabrata (2 to 13 mm); Betania Park: 149 specimens of B. glabrata (4 to 13 mm); Santa Lúcia Park: 2,431 specimens of B. straminea (3 to 9 mm); and Lagoa do Nado Park: 3 specimens of B. tenagophila (3 to 10 mm). Visits to the parks will continue, and after a diagnosis of each park's situation, control and/or eradication measures suitable for each one will be proposed to the municipal authorities.     

Schistosomiasis mansoni in the southwest of the State of Minas Gerais (Brazil)

A new focus of schistosomiasis mansoni at Passos, a town in the Southwest of the State of Minas Gerais (Brazil), region until now considered free of the disease is reported. Malacological surveys showed Biophalaria glabrata naturally infected with Schistosoma mansoni in a country club near Passos. All B. straminea captured at the pisciculture station of the Furnas hydroelectric dam were negative. Six out of seven individuals living in the country club were found to be infected with S. mansoni, including four children who had never been out of Passos. The epidemiological importance of these findings is discussed.     

Abundance and infection of Biomphalaria glabrata with Schistosoma glabrata in the state of Rio de Janeiro, Brazil]

OBJECTIVES: To investigate the spatial distribution, abundance and natural schistosomiasis infection levels in the snail Biomphalaria glabrata, the intermediate host of Schistosoma mansoni in an area of the State of Rio de Janeiro, Brazil. METHODS: In the Pamparr?o area, Sumidouro county, RJ, Brazil, snail captures were carried out every other month from June 1991 to November 1995. There were 23 collecting sites along the Pamparr?o stream and its three tributaries (A, B and C). Captured snails were examined in the laboratory for infection. Data analyses were performed using Spearman coefficient (0.5% significance level) and Qui-square test. RESULTS: The abundance of B. glabrata was variable in both time and space. Most of the collection sites showed a negative correlation with rainfall. The tributary B had the highest and most steady infection rates (more than 25% in some sites). There were found significantly more infected snail in the dry season (chi2 = 20.08; p=0.001). CONCLUSIONS: B. glabrata population in the Pamparr?o valley was negatively influenced by rainfall, especially at the Pamparr?o stream. The dry season seems to promote the infection probably due to the lower water volume, increasing the chance of interaction between the intermediate host and the parasite.     

The distribution of Biomphalaria (Gastropoda, Planorbidae) in the states of Rio Grande do Sul and Santa Catarina, Brazil]

An analysis to determine new localities colonized by the intermediate snail hosts (B. straminea, B. tenagophila and B. tenagophila tenagophila) of Schistosoma mansoni from Rio Grande do Sul and Santa Catarina States (Brazil) was carried out. As regards the geographical distribution of the schistosomiasis vector, the possible extension of the endemic disease to Southernmost Brazil is commented on.     

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.     

Assessment of schistosomiasis in the Dominican Republic

Active transmission of intestinal schistosomiasis is currently limited to the southeastern part of the Dominican Republic. A population-based stool survey in 1980 detected 4 asymptomatic individuals among 114 selected at random in 2 towns and a rural community in El Seibo Province. The distribution of the transmitting snail, Biomphalaria glabrata, considerably exceeds that of Schistosoma mansoni, extending to the National District and capital city of Santo Domingo and well into certain central valley provinces. There is evidence that transmission sites have shifted during the past three decades because of urban development, molluscicidal activities and, perhaps, introduction of competing mollusks. In spite of intermittent control activities, the combination of domestic and recreational use of streams with consequent fecal contamination, and the extended distribution of B. glabrata indicates that the potential for new transmission foci is as great today as it was 10 years ago. This potential transmission of S. mansoni is a continuing threat to public health in the Dominican Republic.     

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.     

Miracidial attraction by Biomphalaria straminea, Lymnaea columella and Physa sp on miracidia of Schistosoma mansoni BH strain]

The attraction exercised over Schistosoma mansoni miracidia by Biomphalaria straminea, Lymnaea columella and Physa sp using a specially designed apparatus consisting of two circular glass chambers joined by an open channel were studied. The molluscs or their snail-conditioned water (SCW) was placed in one of the chambers (randomly chosen). In the channel ten miracidia was deposited and the count of miracidia in each of the three compartments (the two chambers and the channel) was recorded during fifteen minutes. Ten replications of each experiment with different specimens of molluscs and miracidia were made. Statistical and ad-hoc exploratory data analysis showed that: a) the three species of molluscs and their SCW attract the miracidia; b) Physa sp attract more miracidia then L. columella. There was an isolated single B. straminea specimen that had a repulsive effect to the miracidia.     

Outcome in critically ill patients with candidal fungaemia: Candida albicans vs. Candida glabrata

In a retrospective study (1 January 1992-12 December 1998), we investigated population characteristics and outcome in critically ill patients with fungaemia involving C. albicans (n=41) and C. glabrata (n=15). Patients with C. glabrata fungaemia were significantly older compared with patients in the C. albicans group (P=0.024). There were no other differences in population characteristics or severity of illness. Logistic regression analysis showed age (P=0.021), the presence of a polymicrobial blood stream infection (P=0.039), and renal failure (P=0.044) to be independent predictors of mortality. There was no significant difference in in-hospital mortality between the C. glabrata and C. albicans groups (60.0% vs. 41.5%; P=0.24). Since age was an independent predictor of mortality, the trend towards a higher mortality in patients with C. glabrata can be explained by this population being significantly older. In conclusion, we found no difference in mortality between patients with fungaemia involving C. albicans and C. glabrata.     

Enhanced detection of Candida in blood cultures with the BACTEC 460 system by use of the aerobic-hypertonic (8B) medium

The blood culture records during the 6-year period 1984-9 were reviewed to compare the performance of the BACTEC aerobic (6B) and aerobic-hypertonic (8B) media for the recovery of Candida spp. and Torulopsis glabrata from blood. There were 137 positive blood culture sets that contained both a 6B and an 8B bottle. Sixty-eight different yeasts were recovered from 65 patients including 35 Candida albicans, 19 C. tropicalis, 6 C. parapsilosis, 4 C. krusei, 1 C. pseudotropicalis and 3 Torulopsis glabrata. The 8B medium detected 120 of the positive cultures (87.6%) and was the only positive medium in 35 (25.6%) sets, while the 6B medium detected 102 positive cultures (74.4%) and was the only positive medium in 17 (12.4%) sets (P less than 0.04). For those sets in which both bottles were positive, radiometric detection occurred first in the 8B bottle in 39 sets and first in the 6B bottle in 11 sets (P less than 0.001). The superior performance of the 8B bottle was not related to the administration of amphotericin B. Cultures of stock strains of C. albicans, C. tropicalis, and C. parapsilosis in 6B and 8B media with and without added blood confirmed the finding that 8B was substantially superior to 6B for the detection of candidaemia. It is concluded that an 8B bottle should be included in the blood culture set whenever candidaemia is suspected.     

Spatial analysis of Biomphalaria glabrata foci and human cases of mansoni schistosomiasis in Porto de Galinhas, Pernambuco State, Brazil, in the year 2000

This article provides information on the spatial distribution of schistosomiasis, correlating snail foci with human cases using spatial analysis. The locations studied were Merepe III, Pantanal, Salinas, and Socó, comprising 70% of the populated area of Porto de Galinhas. Malacological and parasitological surveys by a CPqAM/ FIOCRUZ team at the location where an epidemic occurred in 2000 identified 15 foci of infected B. glabrata. Human cases were also diagnosed and recorded according to residential block. Spatial analysis was performed using the TerraView computer program and Kernel intensity estimation. Total infection rates, considering all collection stations marked out per location, varied from 15% to 32.4%. The 15 infected B. glabrata foci included 9 in Merepe, 2 in Socó, 3 in Salinas, and 1 in Pantanal. The results suggest a strong spatial trend in the risk of schistosomiais transmission in Salinas and Socó. In Merepe, with the most foci and where foci were closer together, individual focal infection rates were lower. Spatial analysis thus showed less concentration of risk as compared to other locations studied. As for human cases, two high-intensity areas were observed, shown on the map in darker colors.     

复发性外阴阴道假丝酵母菌病的病原真菌学与耐药性研究

目的了解引起复发性外阴阴道假丝酵母菌病(RVVC)的主要病原菌及其对10种抗真菌药物的耐药性,为临床治疗选择抗真菌药物提供依据。方法将诊断为RVVC的病例阴道分泌物标本,接种予科玛嘉假丝酵母菌显色培养基进行菌种鉴定,采用Rosco纸片扩散法进行药敏试验。结果159例RVVC病例中分离出假丝酵母菌属178株,其中白色假丝酵母菌122株(68.5%)、光滑假丝酵母菌49株(27.5%);122株白色假丝酵母菌敏感性最高的是两性霉素B(100.0%)、克霉唑(100.0%)、制霉菌素(99.2%)、酮康唑(99.2%),最低的是咪康唑(36.9%);56株非白色假丝酵母菌敏感性最高的是制霉菌素(100.0%)、两性霉素B(98.2%)、益康唑(96.4%),最低的是特比萘芬(0)、氟康唑(60.7%)。结论RVVC的主要致病菌是白色假丝酵母菌和光滑假丝酵母菌,非白色假丝酵母菌感染明显上升,在治疗RVVC时必须进行真菌培养和药敏试验,选择敏感药物,在无药敏结果时可选用制霉菌素、酮康唑、克霉唑。     

Relationship between the pathogenicity of Schistosoma mansoni in mice and the susceptibility of the vector mollusc. I. Cercariae infectivity and worm burden]

The possible influence of the immune mechanisms of the molluscs on the development of the sporocysts and the resultant behavior of the adult worm in the vertebrate host were studied. Two strains of Schistosoma mansoni (BH and SJ) were used. These were genetically selected for their susceptibility and maintained, respectively, in Biomphalaria glabrata and Biomphalaria tenagophila, the natural invertebrate hosts. Experimental groups of mice infected with cercariae proceeding from the two species of molluscs, belonging to generations P, F1, F2, F3 and F4, were formed. The infection rates of the snails, the number of the penetrant cercariae and the worm burden in mice were evaluated. It was concluded that the higher susceptibility of Biomphalaria tenagophila results in a greater ability on the part of the cercarial to develop into adult worms. The higher susceptibility of B. glabrata results in greater power of penetration into mice tegument on the part of the cercariae.     

A one-year survey of candidemia in Belgium in 2002

A total of 211 episodes of bloodstream yeast infections in 207 patients, hospitalized in 28 Belgian hospitals participating in a National Surveillance Program, were evaluated. A total of 81% of the patients were more than 50 years of age. Candida albicans was the cause of infections in 55% of patients, 22% were due to C. glabrata and 13% to C. parapsilosis. The most common predisposing factors were antibacterial therapy (42%), residence in an intensive care unit (32.9%) and presence of an intravascular catheter (29.7%). Most patients had more than one predisposing factor. Fluconazole alone or in association with another antifungal agent was the treatment of choice for 89.7% of the cases. In vitro susceptibility testing of the isolates revealed that 99% were susceptible to amphotericin B, 95% to 5-fluorocytosine, 82% to fluconazole and 69% to itraconazole. Resistance to azoles was more common among C. glabrata isolates in the elderly. We conclude that the frequency of C. albicans infection is decreasing in Belgium and this is associated with the emergence of other species, most notably, C. glabrata.     

Declining prevalence of hepatitis B virus infection in Catalonia (Spain) 12 years after the introduction of universal vaccination

AIMS: To analyze the prevalence of hepatitis B virus infection markers and hepatitis B vaccination in a representative sample of the juvenile and adult population of Catalonia and to evaluate the changes with respect to seroepidemiological surveys carried out in 1989 and 1996. DESIGN: In all subjects anti-HBc and anti-HBs antibodies and HBsAg were determined using an ELISA test. The possible association between sociodemographic variables and the prevalence of markers was analysed by calculating the adjusted odd ratio (simple logistic regression). SETTING: The study was carried out in 2002 in representative samples of the juvenile (5-14 years) and adult population (>or= 15 years) of Catalonia (Spain). MAIN RESULTS: In 2002 the global prevalence of HBsAg+ was 0.7% (95% CI: 0.4-1.0) and that of anti-HBc+ 8.7% (95% CI: 7.6-9.8), values higher than those obtained in 1989 of 1.5% (95% CI: 1.0-2.1) and 15.6 (95% CI: 13.9-17.3). The prevalence of markers of infection increased with age. The only sociodemographic variable significantly associated with the prevalence of hepatitis B virus infection was the place of birth. The risk of infection was twice as high in subjects born outside Catalonia (p<0.01), adjusted OR 2.0 (95% CI: 1.34-2.98) compared with those born in Catalonia. CONCLUSIONS: The results of this study show that the prevalence of hepatitis B virus infection (anti-HBc+) in Catalonia (Spain) is currently the lowest it has ever been and suggest that there has been a change in the pattern of endemicity of hepatitis B virus infection in Catalonia, which has become a country of low endemicity.     

Biomphalaria glabrata in Haiti

Biomphalaria glabrata, an intermediate host for Schistosoma mansoni, was first reported in Haiti in 1891 at one location in the Départment du Nord and in 1977 it was reported at several sites in one additional watershed. Our study identifies two additional locations each on a different watershed plus a third possible site. A wide but discontinuous distribution of the snail on the north coast of Haiti is confirmed (no autochthonous infections with S. mansoni have been reported). While there are many possible explanations for this discontinuous distribution, a role for the competitor Thiara granifera in shaping the current distribution of B. glabrata is suggested. The incursion of B. glabrata into Haiti is not recent but at the same time is not expanding.     

Prevalence and antifungal susceptibility of vaginal yeasts in outpatients attending a gynecological center in Ancona, Italy

Between February 1993 and May 1994 we studied the prevalence of fungal vulvovaginitis among women attending the Obstetric and Gynecology Clinic of the University of Ancona. Out of the 222 patients, 18 (8.2%) women had symptomatic vaginitis and 24 (10.8%) were carriers. Candida albicans was the species most frequently isolated (44.2%), followed by Torulopsis glabrata (28%) and Saccharomyces cerevisiae (16.2%), from symptomatic and carrier patients. The activity of acid proteinase was determined for C. albicans isolated from both symptomatic and carrier patients. All 13 carriers showed low activity for aspartyl proteinase (score 1+), while 5 of 6 symptomatic patients showed higher activity (score 2+), with a significant difference (p = 0.026). In general, isolates of T. glabrata and S. cerevisiae were less susceptible in vitro to fluconazole than isolates of C. albicans. We did not find any differences in fluconazole MIC results among the C. albicans strains isolated from symptomatic and carrier patients. On the other hand, the fluconazole MICs of T. glabrata and S. cerevisiae isolates showed statistically significant differences between symptomatic and carrier patients (p = 0.009 and p = 0.000, respectively). The differences in proteinase secretion between the isolates from symptomatic and carrier patients suggest a correlation between proteinase production and vaginal candidiasis caused by C. albicans. Torulopsis glabrata, however, was found to be the most common causative agent of vaginitis (7 out 19 episodes), followed by C. albicans (6 out of 19 episodes). Due to the varying patterns of antifungal susceptibility, mainly to fluconazole for the yeast isolates considered in this study, an in vitro susceptibility testing program might be useful for monitoring the outcome of this infection.     

Schistosomiasis in an ecotourism area in Minas Gerais State, Brazil

This paper discusses schistosomiasis transmission in S?o José da Serra, a village with a population of 500 in the county of Jaboticatubas, Minas Gerais State, Brazil. The area receives thousands of visitors a year for ecotourism. The study was motivated by a case of acute schistosomiasis involving a couple that spent the 2007 Carnival (Mardi Gras) holiday in the area. Stool tests from 268 local residents (53.6% of the population) showed that 35 (13%) were positive for the infection. A comparison with a previous survey (2005) in the same location showed an increase in the schistosomiasis-positive rate from 9.6% to 12.5%, among the 56 individuals who participated in both surveys. A malacological survey of 65 Biomphalaria glabrata snails showed one specimen (1.5%) eliminating cercariae. In a similar survey in 2005, no positive snail specimens were found. The study indicates that active schistosomiasis transmission is occurring in the area, and that integrated educational programs are needed for both the local community and tourists.