Eurytrema coelomaticum: influence of the infection on the reproduction and nucleic acids contents in the albumen gland and ovotestis of Bradybaena similaris

The number of eggs laid per snail in Bradybaena similaris and the nucleic acids (DNA and RNA) in the albumen gland and ovotestis were quantified in snails infected with sporocysts of the digenetic trematode Eurytrema coelomaticum. The total number of eggs laid per mollusc was reduced by 96.32% at the end of the larval development. The DNA concentration increased by 700% and the RNA concentration was reduced by 8,38% by the time when the daughter sporocysts of E. coelomaticum were released from B. similaris. The relation between these values and the inhibition of the reproduction observed in infected molluscs is discussed.

Compositional Constraints in the Extremely GC-poor Genome of Plasmodium falciparum

We have analyzed the compositional properties of coding (protein encoding) and non-coding sequences of Plasmodium falciparum, a unicellular parasite characterized by an extremely AT-rich genome. GC% levels, base and dinucleotide frequencies were studied. We found that among the various factors that contribute to the properties of the sequences analyzed, the most relevant are the compositional constraints which operate on the whole genome

Molecular Epidemiology of Human Polyomavirus JC in the Biaka Pygmies and Bantu of Central Africa

Polyomavirus JC (JCV) is ubiquitous in humans and causes a chronic demyelinating disease of the central nervous system , progressive multifocal leukoencephalopathy which is common in AIDS. JCV is excreted in urine of 30-70% of adults worldwide. Based on sequence analysis of JCV complete genomes or fragments thereof, JCV can be classified into geographically derived genotypes. Types 1 and 2 are of European and Asian origin respectively while Types 3 and 6 are African in origin. Type 4, a possible recombinant of European and African genotypes (1 and 3) is common in the USA. To delineate the JCV genotypes in an aboriginal African population, random urine samples were collected from the Biaka Pygmies and Bantu from the Central African Republic. There were 43 males and 25 females aged 4-55 years, with an average age of 26 years. After PCR amplification of JCV in urine, products were directly cycle sequenced. Five of 23 Pygmy adults (22%) and four of 20 Bantu adults (20%) were positive for JC viruria. DNA sequence analysis revealed JCV Type 3 (two), Type 6 (two) and one Type 1 variant in Biaka Pygmies. All the Bantu strains were Type 6. Type 3 and 6 strains of JCV are the predominant strains in central Africa. The presence of multiple subtypes of JCV in Biaka Pygmies may be a result of extensive interactions of Pygmies with their African tribal neighbors during their itinerant movements in the equatorial forest.

Profile of organic acid concentrations in the digestive gland and hemolymph of Biomphalaria glabrata under estivation

Using high performance liquid chromatography (HPLC) analysis it was possible to determine simultaneously the concentration of organic acids (pyruvate, lactate, succinate, fumarate, malate, acetate, propionate, acetoacetate, and ß-hydroxybutyrate) in the digestive gland and the extracellular concentration of these same acids in the hemolymph of estivating Biomphalaria glabrata, the intermediate host of Schistosoma mansoni. After a 7 day period of estivation, there was a significant increase in the tissue levels of lactate, succinate, malate and acetate compared to non-estivating snails. After 14 days of estivation, the levels of lactate and acetate were also significantly elevated. The hemolymph concentrations of pyruvate and acetate increased significantly after 7 days and acetate concentrations continued to be significantly increased up to 14 days of estivation. The other organic acids studied, such as ketone body acetoacetate and ß-hydroxybutyrate or the volatile acid propionate, did not accumulate. Their tissue concentrations, however, increased on the 7th day of estivation and reached normal levels within two weeks of estivation for some of them. One should take into consideration how the reduction in metabolism can be handled under aerobic conditions, and what role anaerobic pathways may play in both energy formation and redox balance processes.

Fibrogenesis and collagen resorption in the heart and skeletal muscle of Calomys callosus experimentally infected with Trypanosoma cruzi: immunohistochemical identification of extracellular matrix components

Intense inflammatory lesions and early development of interstitial fibrosis of the myocardium and skeletal muscle with spontaneous regression, have been described in Calomys callosus infected with Trypanosoma cruzi. The genetic types of collagen present in this model were investigated through immunohistochemistry using specific antibodies, combined with histopathology and Picro-Sirius staining of collagen. Thirty-five calomys were infected with the Colombian strain of T. cruzi and sacrificed at 24, 30, 40, 60 and 90 days post-infection. Inflammatory lesions and fibrogenesis were prominent at the early phase of infection and significantly decreased during late infection. Immunoisotyping of the matrix components was performed by indirect immunofluorescence on 5 µm thick cryostat sections using specific antibodies against laminin, fibronectin and isotypes I, III and IV of collagen. In the early phase, positive deposits of all the matrix components were present, with predominance of fibronectin, laminin and collagens types I and III in the myocardium and of types III and IV in the skeletal muscles. From the 40th day, type IV collagen predominates in the heart. At the late phase of infection (60th to 90th day), a clear fragmentation and decrease of all the matrix components were detected. Findings of the present study indicate that a modulation of the inflammatory process occurs in the model of C. callosus, leading to spontaneous regression of fibrosis independent of the genetic types of collagen involved in this process.

Monitoring of the dissemination of Salmonella in the chicken Frankfurt-sausage productionline of a sausage factory in the state of São Paulo, Brazil

Poultry meat and its derivatives are among the foodstuffs considered by environmental health authorities to present the highest risks to the public. A total of 185 samples were collected in five monthly batches, from different processing stages in a sausage plant that uses mechanically-deboned chicken meat (MDCM), and testedfor the presence of Salmonella. Enrichment was carried out in both Kauffman's tetrathionate broth and Rappaport-Vassiliadis broth and isolation on Salmonella-Shigella agar and brilliant-green agar. Live Salmonella bacteria were isolated from six samples of the raw meat and from the emulsion, in batches three, four, and five, but not from any sample in batches one or two. The six isolated strains were all classified as Salmonella Albany, which has not previously been reported in MDCM. Of the two enrichment broths, Rappaport-Vassiliadis gave the better results. The pattern of contamination suggests a probable common source, given that a new supplier was used in the third, fourth, and fifth months. It was also shown that the industrial cooking was effective in preventing Salmonella surviving in the final product.

Detection of Mycobacterium leprae DNA by polymerase chain reaction in the blood and nasal secretion of Brazilian household contacts

DNA samples from blood and nasal swabs of 125 healthy household contacts was submitted to amplification by polymerase chain reaction (PCR) using a Mycobacterium leprae-specific sequence as a target for the detection of subclinical infection with M. leprae.All samples were submitted to hybridization analysis in order to exclude any false positive or negative results. Two positive samples were confirmed from blood out of 119 (1.7%) and two positive samples from nasal secretion out of 120 (1.7%). The analysis of the families with positive individuals showed that 2.5% (n = 3) of the contacts were relatives of multibacilary patients while 0.8% of the cases (n = 1) had a paucibacilary as an index case. All positive contacts were followed up and after one year none of them presented clinical signs of the disease. In spite of the PCR sensitivity to detect the presence of the M. leprae in a subclinical stage, this molecular approach did not seem to be a valuable tool to screen household contacts, since we determined a spurious association of the PCR positivity and further development of leprosy.

Participation of cytokines in the necrotic-inflammatory lesions in the heart and skeletal muscles of Calomys callosus infected with Trypanosoma cruzi

Calomys callosus, a sylvatic reservoir of Trypanosoma cruzi, when infected with the Colombian strain (Biodeme Type III, T. cruzi I ) develops necrotic-inflammatory lesions and intense early fibrogenesis in the heart and skeletal muscles, that spontaneously regress. Participation of pro-inflammatory and pro-fibrogenic cytokines, such as tumor necrosis factor-alpha (TNF-alpha), gamma interferon (IFN-gamma) , and tumor growth factor-beta (TGF-beta), in the pathogenesis of the lesions is herein studied. Eighty C. callosus weighing 20 to 30 g were used. Seventy of them were inoculated with the Colombian strain (10(5) blood forms) and 10 were maintained as intact non-infected controls. After infection, C. callosus were sacrificed at different time-points from 15 to 70 days. The heart and skeletal muscle were processed for histopathology and cryopreserved for immunohistochemistry. Early necrotic lesions of parasitized skeletal muscle and myocardium with intense inflammatory lesions were present. Search for the in situ presence of TNF-alpha and IFN-gamma, was performed using rat-IgG anti-mouse antibodies against these cytokines. For the in situ search of TGF-beta, rabbit IgG anti-mouse antibodies were used. Immunolabeling of the cytokines in tissues of infected C. callosus was successful. The cytokines TNF-alpha, IFN-gamma , and TGF-beta were detected in the cytoplasm of macrophages and in the necrotic material from 15 to 45 days post-infection, decreasing their intensity until complete disappearance by the 65th day, which correlated with subsiding histopathological lesions. These findings suggest the participation of these cytokines in the control of parasite multiplication, in the development of an early fibrogenesis and in the regression of fibrotic-inflammatory lesions observed in C. callosus.

Taxonomic revision of phlebotomine sand fly species in the series davisi and panamensis of the subgenus Psychodopygus Mangabeira, 1941 (Diptera: Psychodidae: Phlebotominae)

Several species of the subgenus Psychodopygus Mangabeira, 1941 are known to be leishmaniosis vectors in Brazil. Some of them are morphologically similar, which makes their identification quite difficult concerning epidemiological studies. The aim of the current work is to study the morphology of adult specimens of the subgenus Psychodopygus, in accordance with the morphological similarity and still taking into account the epidemiological importance of some species. Thus 11 species have been studied, including four subspecies of adult specimens deposited in the phlebotomine collection of Centro de Pesquisas René Rachou-Fiocruz. Morphological characters found in the literature and new features observed in this study were recorded in a taxonomic discussion format. These characters make it easy to separate such species. Four taxa, previously considered as subspecies, were raised to the category of species.

Tuberculosis in the New World: a study of ribs from the Schild Mississippian population, West-Central Illinois

Vertebral lesions have been the main evidence for infection by the Mycobacterium tuberculosis complex (MTC) in paleopathology. Skeletal involvement is expected in a small percentage of infected individuals. Recently, several authors report a correlation between rib lesions and tuberculosis (TB) complex infection. This study tests the hypothesis that rib lesions can serve as a useful marker for MTC infection within the Mississippian Schild skeletal collection from West-Central Illinois. Ribs from 221 adults and juveniles were examined, and affected individuals were tested for TB complex infection. DNA from rib samples of affected individuals was amplified with primers targeting the IS6110 insertion element, which is common to all members of the TB complex. Although it cannot allow discrimination between different species of TB, IS6110 is present in many copies within their genomes, and its presence is thus an indication of MTC infection. The results support the use of rib lesions as a marker for TB infection. Additionally, we demonstrate that MTC DNA can be recovered from ribs that lack lesions in individuals who have lesions of other bones. We recommend that an examination of ribs be incorporated into investigations for TB.

The role of triple infection with hepatitis B virus, hepatitis C virus, and human immunodeficiency virus (HIV) type-1 on CD4+ lymphocyte levels in the highly HIV infected population of North-Central Nigeria

We set out to determine the seroprevalence of hepatitis B and C among human immunodeficiency virus type-1 (HIV-1) infected individuals in North-Central Nigeria to define the influence of these infections on CD4+ lymphocytes cells among our patients as access to antiretroviral therapy improves across the Nigerian nation. The CD4+ values of 180 confirmed HIV-1 infected individuals were enumerated using a superior fluorescence-activated cell sorter system. These patients were tested for the presence of hepatitis B surface antigen and anti-hepatitis C virus (HCV) using third generation enzyme-linked immunosorbent assays. Fifty (27.8%) patients had active hepatitis B virus (HBV) infection while 33 (18.3%) tested positive for anti-HCV antibody. Of these infections, 110 (61.1%), 37 (20.6%), and 20 (11.1%) had HIV only, HBV/HIV-only, and HCV/HIV-only respectively. A HBV/HCV/HIV coinfection prevalence of 7.2% (13 patients) was recorded. Patients coinfected with HIV/HBV/HCV appeared to have lower CD4+ counts (mean = 107 cells/µl; AIDS defining) when compared to HBV/HIV-only (mean = 377 cells/µl), HCV/HIV-only (mean = 373 cells/µl) and patients with mono HIV infection (mean = 478 cells/µl). Coinfection with HBV or HCV is relatively common among HIV-infected patients in Nigeria and should be a big consideration in the initiation and choice of therapy.

Intragenomic variation in the second internal transcribed spacer of the ribosomal DNA of species of the genera Culex and Lutzia (Diptera: Culicidae)

Culex is the largest genus of Culicini and includes vectors of several arboviruses and filarial worms. Many species of Culex are morphologically similar, which makes their identification difficult, particularly when using female specimens. To aid evolutionary studies and species distinction, molecular techniques are often used. Sequences of the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) from 16 species of the genus Culex and one of Lutzia were used to assess their genomic variability and to verify their applicability in the phylogenetic analysis of the group. The distance matrix (uncorrected p-distance) that was obtained revealed intragenomic and intraspecific variation. Because of the intragenomic variability, we selected ITS2 copies for use in distance analyses based on their secondary structures. Neighbour-joining topology was obtained with an uncorrected p-distance. Despite the heterogeneity observed, individuals of the same species were grouped together and correlated with the current, morphology-based classification, thereby showing that ITS2 is an appropriate marker to be used in the taxonomy of Culex.

Human rhinovirus in the lower respiratory tract infections of young children and the possible involvement of a secondary respiratory viral agent

Human rhinoviruses (HRV) are usually associated with mild respiratory symptoms in children. However, some studies have found that HRV can cause severe disease, especially when the patient is co-infected with a second virus. In this study, 532 nasopharyngeal aspirates (NPAs) were collected over a nine-year period from children at the Clinics Hospital of Uberlândia. The collected NPAs were then tested for HRV RNA using the reverse transcription-polymerase chain reaction. Eighty-three specimens from children diagnosed with lower respiratory tract illness (LRTI) were positive for HRV RNA and were then tested for the presence of eight other respiratory viruses. A second virus was detected in 37.3% (31/83) of the samples. The most frequent clinical diagnosis was bronchiolitis, followed by other LRTI and then pneumonia. The frequency of severe disease in children infected with more than one virus was not significantly different from the frequency of severe disease in children infected with HRV alone. Children infected with both HRV and parainfluenza virus (1.5 m.o.) were significantly younger than those infected by HRV alone (5.0 m.o.) (p = 0.0454). Overall, these results suggest that infection with a second virus does not lead to a higher frequency of severe syndromes in children presenting with LRTI.

Proteolytic activity in the adult and larval stages of the human roundworm parasite Angiostrongylus costaricensis

Angiostrongylus costaricensis is a nematode that causes abdominal angiostrongyliasis, a widespread human parasitism in Latin America. This study aimed to characterize the protease profiles of different developmental stages of this helminth. First-stage larvae (L1) were obtained from the faeces of infected Sigmodon hispidus rodents and third-stage larvae (L3) were collected from mollusks Biomphalaria glabrata previously infected with L1. Adult worms were recovered from rodent mesenteric arteries. Protein extraction was performed after repeated freeze-thaw cycles followed by maceration of the nematodes in 40 mM Tris base. Proteolysis of gelatin was observed by zymography and found only in the larval stages. In L3, the gelatinolytic activity was effectively inhibited by orthophenanthroline, indicating the involvement of metalloproteases. The mechanistic class of the gelatinases from L1 could not be precisely determined using traditional class-specific inhibitors. Adult worm extracts were able to hydrolyze haemoglobin in solution, although no activity was observed by zymography. This haemoglobinolytic activity was ascribed to aspartic proteases following its effective inhibition by pepstatin, which also inhibited the haemoglobinolytic activity of L1 and L3 extracts. The characterization of protease expression throughout the A. costaricensis life cycle may reveal key factors influencing the process of parasitic infection and thus foster our understanding of the disease pathogenesis.

Cells and mediators of inflammation (C-reactive protein, nitric oxide, platelets and neutrophils) in the acute and convalescent phases of uncomplicated Plasmodium vivax and Plasmodium falciparum infection

The haematological changes and release of soluble mediators, particularly C-reactive protein (CRP) and nitric oxide (NO), during uncomplicated malaria have not been well studied, especially in Brazilian areas in which the disease is endemic. Therefore, the present study examined these factors in acute (day 0) and convalescent phase (day 15) patients infected with Plasmodium falciparum and Plasmodium vivax malaria in the Brazilian Amazon. Haematologic parameters were measured using automated cell counting, CRP levels were measured with ELISA and NO plasma levels were measured by the Griess reaction. Our data indicate that individuals with uncomplicated P. vivax and P. falciparum infection presented similar inflammatory profiles with respect to white blood cells, with high band cell production and a considerable degree of thrombocytopaenia during the acute phase of infection. Higher CRP levels were detected in acute P. vivax infection than in acute P. falciparum infection, while higher NO was detected in patients with acute and convalescent P. falciparum infections. Although changes in these mediators cannot predict malaria infection, the haematological aspects associated with malaria infection, especially the roles of platelets and band cells, need to be investigated further.