Survival, Population Size, and Gonotrophic Cycle Duration of Nyssomyia neivai (Diptera: Psychodidae) at an Endemic Area of American Cutaneous Leishmaniasis in Southeastern Brazil

The survival, absolute population size, gonotrophic cycle duration, and temporal and spatial abundance of Nyssomyia neivai (Pinto) were studied in a rural area endemic for American cutaneous leishmaniasis (ACL) in Conchal, Sao Paulo State, southeastern Brazil, using mark-release-recapture techniques and by monitoring population fluctuation. The monthly abundance exhibited a unimodal pattern, with forest and domicile habitats having the highest relative abundances. A total of 1,873 males and 3,557 females were marked and released during the six experiments, of which 4.1-13.0% of males and 4.1-11.8% of females were recaptured. Daily survivorship estimated from the decline in recaptures per day was 0.681 for males and 0.667 for females. Gonotrophic cycle duration was estimated to be 4.0 d. Absolute population size was calculated using the Lincoln Index and ranged from 861 to 4,612 males and from 2,187 to 19,739 females. The low proportion of females that reach the age when they are potentially infective suggests that N. neivai has a low biological capacity to serve as a vector and that factors such as high biting rates and opportunistic feeding behavior would be needed to enable Leishmania (Viannia) braziliensis Vianna transmission. This agreed with the epidemiological pattern of ACL in southeastern Brazil that is characterized by low incidence, with isolated cases acquired principally within domiciliary habitats.

Observations on the feeding habits of Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) in Campo Grande, an endemic area of visceral leishmaniasis in Mato Grosso do Sul, Brazil

Sand flies were captured weekly with CDC light traps from December 2003 to November 2005 in three areas of Campo Grande, in the Brazilian state of Mato Grosso do Sul. These areas incorporated two patches of remnant forest and five houses. The blood meals of engorged female sand flies were identified using the avidin-biotin system of immunoenzymatic ELISA capture. Most (327/355) of the females analysed were Lutzomyia longipalpis, of which 66.4% reacted with human blood, 64.8% with that of birds and 8.9% with that of dogs. Females that had taken human blood predominated in the residential areas and two forest patches. The following combinations of blood were also detected for L. longipalpis in some of the samples analysed: bird + human (43.4%), bird + human + dog (6.1%). The combination bird + human + dog + pig was also found for Nyssomyia whitmani. Dogs and pigs appear to have little attractiveness for L. longipalpis. The results obtained demonstrate the eclecticism and high anthropophily of L. longipalpis and raise new questions with regard to the importance of dogs in VL epidemiology and the possible role of man as a source of infection for sand flies. (C) 2008 Elsevier B.V. All rights reserved.

Seasonal variation of Lutzomyia longipalpis (Lutz & neiva, 1912) (Diptera : Psychodidae : Phlebotominae) in endemic area of visceral leishmaniasis, Campo Grande, state of Mato Grosso do Sul, Brazil

The seasonal distribution of Lutzomyia longipalpis was studied in two forested and five domiciliary areas of the urban area of Campo Grande; MS, from December 2003 to November 2005. Weekly captures were carried out with CDC light traps positioned on ground and in the canopy inside a residual forest and on the edge (ground) of a woodland and in at least one of the following ecotopes in peridomiciles-a cultivated area, a chicken coop, a pigsty, a kennel, a goat and sheep shelter and an intradomicile. A total of 9519 sand flies were collected, 2666 during the first year and 6853 during the second. L. longipalpis was found throughout the 2-year period, presenting smaller peaks at intervals of 2-3 months and two greater peaks, the first in February and the second in April 2005, soon after periods of heavy rain. Only In one of the woodlands was a significant negative correlation (p < 0.05) between the number of insects and temperature during the first year and the climatic factors (temperature, RHA and rain) was observed. In the domiciliary areas in four domiciles some positive correlations (p < 0.05) occurred in relation to one or more climatic factors; however, the species shows a clear tendency to greater frequency (72%) in the rainy season than in the dry (28%). Thus, we recommend an intensification of the VL control measures applied in Campo Grande, MS, during the rainy season with a view to reducing the risk of the transmission of the disease. (C) 2007 Elsevier B.V. All fights reserved.

Clonal Relationship among Atypical Enteropathogenic Escherichia coli Strains Isolated from Different Animal Species and Humans

Forty-nine typical and atypical enteropathogenic Escherichia coli (EPEC) strains belonging to different serotypes and isolated from humans, pets (cats and dogs), farm animals (bovines, sheep, and rabbits), and wild animals (monkeys) were investigated for virulence markers and clonal similarity by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The virulence markers analyzed revealed that atypical EPEC strains isolated from animals have the potential to cause diarrhea in humans. A close clonal relationship between human and animal isolates was found by MLST and PFGE. These results indicate that these animals act as atypical EPEC reservoirs and may represent sources of infection for humans. Since humans also act as a reservoir of atypical EPEC strains, the cycle of mutual infection of atypical EPEC between animals and humans, mainly pets and their owners, cannot be ruled out since the transmission dynamics between the reservoirs are not yet clearly understood.

Molecular detection of enterotoxins in environmental strains of Aeromonas hydrophila and Aeromonas jandaei

Aeromonas species are widely distributed in aquatic environments and recent studies include the genus in the emergent pathogens group because of its frequent association with local and systemic infections in immunocompetent humans. Aiming to search for virulence genes in environmental strains of Aeromonas hydrophila and Aeromonas jandaei, we designed specific primers to detect act/hly A/aer complex and alt genes. Primers described elsewhere were used to detect ast. Eighty-seven strains previously identified using phenotypic and genotypic tests as A. hydrophila (41) and A. jandaei (46) were analysed for the presence of the virulence genes using PCR. DNA fragments of expected size were purified and directly sequenced. Among the 41 strains of A. hydrophila 70.7% (29), 97.6% (40) and 26.8% (11) possessed act/hly A/aer complex, ast and alt genes, respectively. Among the 46 strains of A. jandaei, 4.4% (2), 0% (0) and 32.6% (15) were positive for act/hly A/aer complex, ast and alt genes, respectively. Sequencing allowed for the confirmation of amplified products using BLAST. The present work proposes a specific and rapid diagnostic method to detect the main virulence determinants of Aeromonas, a genus potentially pathogenic to humans.

Color inheritance and pigment characterization of red (wild-type), greenish-brown, and green strains of Gracilaria birdiae (Gracilariales, Rhodophyta)

Species of Gracilaria are some of the most useful algae in the world for the production of agar. As a consequence of its economic importance, the genus has been the subject of many studies worldwide. Color variants of Gracilaria birdiae have been found in the natural population on the Brazilian coast, and they have also been isolated from plants cultivated in laboratory. These findings raised new questions regarding intraspecific variation and the prospects of cultivating such variants for their agar production. Therefore, this work aimed to determine the mode of color inheritance for two G. birdiae strains: a greenish-brown strain (gb) found in a natural population and a green strain (gr) which had arisen as a spontaneous mutation in a red plant cultured in the laboratory. The pigment contents of these strains, as well as the red wildtype (rd), were also characterized. Crosses between female and male plants of the same color (rd, gr, or gb) and between different colors were performed. Crosses between plants of the same color showed tetrasporophytic and gametophytic descendents of the parental color. Recessive nuclear inheritance was found in the greenish-brown strain, and cytoplasmic maternal inheritance was found in the green strain; both had lower phycoerythrin and higher concentrations of allophycocyanin and phycocyanin than the wild-type. Chlorophyll a contents were similar among all strains. Taken together, our results contribute to knowledge about the variability of this important red algae. In addition, since greenish-brown and green strains showed stability of color, both could be selected and tested in experimental sea cultivation to evaluate if mutants have advantageous performance when compared with red strain.

Effects of kinetin and nitrogen on growth rates, pigment and protein contents in wild and phycoerythrin-deficient strains of Hypnea musciformis (Rhodophyta)

Hypnea musciformis (Wulfen in Jacqu.) J.V. Lamour. is the main source for carrageenan production in Brazil and strains with selected characteristics could improve the production of raw material. The effects of kinetin on growth rates, morphology, protein content, and concentrations of pigments (chlorophyll a, phycoerythrin, phycocyanin, and allophycocyanin) were assessed in the wild strain (brown phenotype) and in the phycoerythrin-deficient strain (green phenotype) of H. musciformis. Concentrations of kinetin ranging from 0 to 50 mu M were tested in ASP 12-NTA synthetic medium with 10 mu M nitrate (N-limited) and 100 mu M nitrate (N-saturated). In N-limited condition, kinetin stimulated growth rates of the phycoerythrin-deficient strain and formation of lateral branches in both colour strains. Kinetin stimulated protein biosynthesis in both strains. However, differences between both nitrogen conditions were significant only in the phycoerythrin-deficient strain. In the wild strain, effects of kinetin on concentrations of phycobiliproteins were not significant in both nitrogen conditions, except for chlorophyll content. However, the phycoerythrin-deficient strain showed an opposite response, and kinetin stimulated the phycobiliprotein biosynthesis, with the highest concentrations of phycoerythrin in N-saturated medium, while the highest concentrations of allophycocyanin and phycocyanin were observed in N-limited medium. These results indicate that the effects of kinetin on growth, morphology, protein and phycobiliprotein contents are influenced by nitrogen availability, and the main nitrogen storage pools in phycoerythrin-deficient strain of H. musciformis submitted to N-limited conditions were phycocyanin and allophycocianin, the biosynthesis of which was enhanced by kinetin.

Seed dispersal and predation in the endemic Atlantic rainforest palm Astrocaryum aculeatissimum across a gradient of seed disperser abundance

Tropical forests have been subject to intense hunting of medium and large frugivores that are important in dispersing large-seeded species. It has been hypothesized that in areas with extinction or low abundance of medium and large-bodied animals the density of small rodents may increase. Therefore, this increment in the density of small rodents may compensate for the absence or low abundance of medium and large frugivores on seed removal and seed dispersal. Here, we fill up this gap in the literature by determining if seed removal, seed dispersal, and seed predation by small rodents (spiny rats, Trinomys inheringi and squirrels, Sciurus ingrami) are maintained in defaunated areas. We accessed seed removal, seed dispersal, seed predation, and seedling recruitment of an endemic Atlantic rainforest palm, Astrocaryum aculeatissimum, in a gradient of abundance of agoutis. We found that seed removal, scatter hoarding, and seed predation increase with the abundance of agoutis. In contrast, the proportion of dispersed but non-cached seeds decreased with the abundance of agoutis. We did not find any effect of the abundance of agoutis on seed dispersal distance, but we did find a positive trend on the density of seedlings. We concluded that small rodents do not compensate the low abundance of agoutis on seed removal, scatter hoarding, and seed predation of this palm tree. Moreover, areas in which agoutis are already extinct did not present any seed removal or scatter hoarding, not even by small rodents. This study emphasizes both the importance of agoutis in dispersing seeds of A. aculeatissimum and the collapse in seed dispersal of this palm in areas where agoutis are already extinct.

Isolation and characterization of microsatellite loci in Epidendrum puniceoluteum, an endemic orchid from the Atlantic Rainforest

Epidendrum puniceoluteum is an endemic orchid of Atlantic Rainforest, restricted to few populations only due to the destruction and fragmentation of its native habitat. Here, we report on the development of 10 microsatellite markers isolated from this orchid species. Genetic variability was characterized in two distant populations from Brazil coast. The number of alleles observed for each locus ranged from two to 12 and with an average of 6.4 alleles per locus. These microsatellites should be valuable tools for studying both fine-scale genetic structure of scattered E. puniceoluteum population and patterns will be useful genetic markers for other closely related taxa.

Patterns of Antibodies Against Latent and Lytic Antigens of Human Herpesvirus 8 in an Endemic Population and Patients With Kaposi`s Sarcoma in Mozambique

The patterns of antibodies against latent and lytic antigens of human herpesvirus 8 (HHV-8) were assessed using immunofluorescence assays of samples from 155 persons seropositive for HHV-8 seen at public health centers and 24 patients with Kaposi`s sarcoma (KS) from Mozambique. Of the 155 persons without KS, 48(31%) had antibodies against latent antigens only, 29 (18.7%) had antibodies against lytic antigens only, and 78 (50.3%) had antibodies against both types of antigen. The HHV-8 antibody titer tended to increase with age until age 40, after which it began to decrease. High titers of antibodies against latent and lytic antigens of HHV-8 were detected mostly in persons co-infected with HIV, and these increased titers could have a predictive value. All patients with KS except four patients who were seronegative for HHV-8 had elevated titers of HHV-8 antibodies, predominantly against latent antigens. The data suggest the potential for an increase in the development of KS in this endemic area for HHV-8. J. Med. Virol. 82:1576-1581, 2010. (C) 2010 Wiley-Liss, Inc.

Seroprevalence of Human Herpesvirus 8 Infection in Individuals From Health Care Centers in Mozambique: Potential for Endemic and Epidemic Kaposi`s Sarcoma

Human herpesvirus 8 (HHV-8) infection is common in sub-Saharan Africa, but its prevalence in Mozambique is unknown. The seroprevalence of HHV-8 in a cohort of individuals seen at public health centers in Northern (n = 208), Central (n = 226), or Southern (n = 318) Mozambique was examined. All individuals were interviewed to obtain socioeconomic, demographic and clinical data and were tested for serum anti-HHV-8 antibodies using an immunofluorescence assay. The overall frequency of HHV-8 antibodies was 21.4% and, in spite of the diversity of epidemiological characteristics of the tested individuals, did not differ significantly among regions: 18.7%, 24.3% and 21.4% in the North, Center, and South, respectively (chi(2), 2.37; P = 0.305). The variables that were associated significantly with the presence of HHV-8 antibodies were gender, age, level of education, number of siblings and HIV serostatus, but these differed across the regions. In the North, although tested individuals lived under poor socioeconomic conditions, no association between HHV-8 infection and household variables was detected, with the exception of the number of siblings (P = 0.042). In the Central region, HHV-8 infection was associated with gender (P = 0.010), the number of household members (P = 0.031), and the place of attendance (P = 0.021). In the South, HHV-8 infection was associated with the number of siblings (P = 0.023) and HIV status (P = 0.002). The overall prevalence of HHV-8 seropositivity increased with age. These results demonstrate that Mozambique is another country in Africa with endemic HHV-8 infection, and, because of the AIDS epidemic, continued access to antiretroviral treatment is necessary to avert an outbreak of AIDS-Kaposi`s sarcoma. J. Med. Virol. 82:1216-1223, 2010. (C) 2010 Wiley-Liss, Inc.

Clinical correlations of human cytomegalovirus strains and viral load in kidney transplant recipients

Little is known about clinical differences associated with cytomegalovirus (CMV) infection by distinct strains in renal transplant patients. Different clinical pictures may be associated with specific viral genotypes. viral load, as well as host factors. The objective of this study was to identify CMV strains to determine viral load (antigenemia), and their correlation with clinical data in renal transplant recipients. Seventy-one patients were enrolled, comprising 91 samples. After selection, polymorphonuclear cells were used to amplify and sequence the gB region of CMV DNA. The sequences were analyzed to ascertain the frequency of different genotypes. Additionally, the results of this Study showed that the gB coding gene presents a great variability, revealing a variety of patterns: classical gB (1.4%), gB1V (46.4%), classical gB2 (35.2%), gB2V (2.8%), gB3 (1.4%), classical gB4 (4.9%) and gB4V (4.9%). The mean viral load in kidney transplant patient was 75.1 positive cells (1-1000). A higher viral load was observed in patients with genotype 4 infection. Statistically significant differences were detected between gB1 and gB4 (p=0.010), and between gB2 and gB4 (p=0.021). The average numbers of positive cells in relation to clinical presentation were: 34.5 in asymptomatic, 49.5 in CMV associated syndrome and 120.7 in patients with invasive disease (p=0.048). As a group, gB1 was the most frequent strain and revealed a potential risk for developing invasive disease. Viral load also seemed to be important as a marker associated with clinical presentation of the disease. (C) 2008 Elsevier B.V. All rights reserved.

Strain variation in ppGpp concentration and RpoS levels in laboratory strains of Escherichia coli K-12

Laboratory strains and natural isolates of Escherichia coli differ in their level of stress resistance due to strain variation in the level of the sigma factor sigma(S) (or RpoS), the transcriptional master controller of the general stress response. We found that the high level of RpoS in one laboratory strain (MC4100) was partially dependent on an elevated basal level of ppGpp, an alarmone responding to stress and starvation. The elevated ppGpp was caused by two mutations in spoT, a gene associated with ppGpp synthesis and degradation. The nature of the spoT allele influenced the level of ppGpp in both MC4100 and another commonly used K-12 strain, MG1655. Introduction of the spoT mutation into MG1655 also resulted in an increased level of RpoS, but the amount of RpoS was lower in MG1655 than in MC4100 with either the wild-type or mutant spoT allele. In both MC4100 and MG1655, high ppGpp concentration increased RpoS levels, which in turn reduced growth with poor carbon sources like acetate. The growth inhibition resulting from elevated ppGpp was relieved by rpoS mutations. The extent of the growth inhibition by ppGpp, as well as the magnitude of the relief by rpoS mutations, differed between MG1655 and MC4100. These results together suggest that spoT mutations represent one of several polymorphisms influencing the strain variation of RpoS levels. Stress resistance was higher in strains with the spoT mutation, which is consistent with the conclusion that microevolution affecting either or both ppGpp and RpoS can reset the balance between self-protection and nutritional capability, the SPANC balance, in individual strains of E coli.