Spatio-temporal analysis of the visceral leishmaniasis in the state of Alagoas, Brazil / Análise espacial-temporal da leishmaniose visceral no estado de Alagoas

Visceral leishmaniosis is a neglected tropical disease. We evaluated the spatial distribution of cases of visceral leishmaniosis in the state of Alagoas, Brazil. All cases of VL, registered by the health department, were analyzed and georeferenced. Results: Between 2008 and 2017, 97.1% of the municipalities presented sporadic classification of transmission. With temporal evolution, the incidence of cases of visceral leishmaniosis was concentrated in most municipalities in the microregion of Santana do Ipanema-AL. Space-time analysis, if considered, may promote the improvement of surveillance and control actions of visceral leishmaniosis.

A leishmaniose visceral é uma doença tropical negligenciada. Foram avaliadas a distribuição espacial dos casos de leishmaniose visceral no estado de Alagoas. Todos os casos de LV, registrados pela secretaria de saúde, foram analisados e georreferenciados. Entre 2008 e 2017, 97,1% dos municípios apresentaram classificação esporádica de transmissão. Com a evolução temporal, a incidência de casos de leishmaniose visceral se concentrou na maioria dos municípios da microrregião de Santana do Ipanema-AL. A análise espaço-tempo, se considerada, pode promover o aprimoramento das ações de vigilância e controle da leishmaniose visceral.

Spatio-temporal analysis of the visceral leishmaniasis in the state of Alagoas, Brazil

Abstract Visceral leishmaniosis is a neglected tropical disease. We evaluated the spatial distribution of cases of visceral leishmaniosis in the state of Alagoas, Brazil. All cases of VL, registered by the health department, were analyzed and georeferenced. Results: Between 2008 and 2017, 97.1% of the municipalities presented sporadic classification of transmission. With temporal evolution, the incidence of cases of visceral leishmaniosis was concentrated in most municipalities in the microregion of Santana do Ipanema-AL. Space-time analysis, if considered, may promote the improvement of surveillance and control actions of visceral leishmaniosis.

Resumo A leishmaniose visceral é uma doença tropical negligenciada. Foram avaliadas a distribuição espacial dos casos de leishmaniose visceral no estado de Alagoas. Todos os casos de LV, registrados pela secretaria de saúde, foram analisados e georreferenciados. Entre 2008 e 2017, 97,1% dos municípios apresentaram classificação esporádica de transmissão. Com a evolução temporal, a incidência de casos de leishmaniose visceral se concentrou na maioria dos municípios da microrregião de Santana do Ipanema-AL. A análise espaço-tempo, se considerada, pode promover o aprimoramento das ações de vigilância e controle da leishmaniose visceral.

The Influence of Cement Removal Techniques on In Situ Bacterial Adhesion and Biodegradation at the Marginal Interface of Ceramic Laminates.

OBJECTIVES: This in situ study aimed to analyze the influence of different resin cement removal techniques on bacterial adhesion and biodegradation at the marginal interface of ceramic laminates. METHODS AND MATERIALS: Eighty feldspathic ceramic (F) blocks were prepared and cemented onto bovine enamel slabs (7×2.5×2 mm). Excess cement was removed using a microbrush (MBR), a scalpel blade (SCP), or a Teflon spatula (TSP). For the biodegradation analysis, 40 disc-shaped resin cement specimens were prepared (7×1.5 mm) using a Teflon mold. The specimens were randomly allocated into two groups: (1) No finishing procedure (only Mylar strip), and (2) with finishing and polishing procedures using the Jiffy system (Ultradent, South Jordan, UT, USA) (n=20). The in situ phase consisted of using an intraoral palatal device by 20 volunteers for 7 days. Each device contained five cylindrical wells (8×3 mm), where three dental blocks and two cement specimens were included in the wells. Surface roughness (Ra) was measured using a contact profilometer. A micromorphological analysis was performed under a stereomicroscope and a scanning electron microscope. Bacterial adhesion was quantitated based on the number of colony-forming units (CFU/mL) and their biofilm development potential. RESULTS: The cement removal techniques directly affected surface roughness at the marginal interface (p<0.001), and the SCP technique produced higher mean roughness, regardless of the surface area analyzed. Surface polishing protected cement specimens from further biodegradation (p=0.148). There were no differences in CFU counts between the groups after the in situ phase (p=0.96). All specimens showed CFU with a strong ability to develop a biofilm. CONCLUSIONS: The techniques used for cement removal increased the surface roughness of ceramic laminates, particularly SCP, but they did not affect bacterial adhesion at the marginal interface. Surface polishing of the resin cement is recommended to mitigate biodegradation.

Spatio-temporal analysis of the visceral leishmaniasis in the state of Alagoas, Brazil.

Visceral leishmaniosis is a neglected tropical disease. We evaluated the spatial distribution of cases of visceral leishmaniosis in the state of Alagoas, Brazil. All cases of VL, registered by the health department, were analyzed and georeferenced. Results: Between 2008 and 2017, 97.1% of the municipalities presented sporadic classification of transmission. With temporal evolution, the incidence of cases of visceral leishmaniosis was concentrated in most municipalities in the microregion of Santana do Ipanema-AL. Space-time analysis, if considered, may promote the improvement of surveillance and control actions of visceral leishmaniosis.

American visceral leishmaniasis in a state of northeastern Brazil: clinical, epidemiological and laboratory aspects / Leishmaniose visceral americana em estado do nordeste brasileiro: aspectos clínicos, epidemiológicos e laboratoriais

In Brazil, American visceral leishmaniasis (AVL) has become a public health concern due to its high incidence and lethality. This study aimed to analyze the clinical, epidemiological, and laboratory aspects of AVL in a state of Brazil. This descriptive, cross-sectional, retrospective, and quantitative study of notified cases of AVL was carried out in Alagoas between 2008 and 2017 from data obtained from DATASUS/SINAN. Sociodemographic, clinical, and laboratory variables were analyzed. A descriptive analysis was performed using absolute values and valid percentages, using tables and/or graphs. Data processing was performed using Stata 12.0®. Results with P <0.05 were considered statistically significant. During the study period, 352 cases of AVL were reported, of which 6.82% died and 38.92% had met a cure criterion. Male patients were predominant (66.76%). Of the total infected patients, 16.76% had attended only the 1st to the 4th grades, with those most affected aged 1 to 4 years (28.69%). Laboratory diagnostic criteria were most commonly used to confirm the notified cases (76.42%), whereas 51.70% and 8.52% of the cases had positive parasitological and immunofluorescence diagnoses, respectively. Finally, the study showed a higher prevalence of the disease in children, men and in rural residents. Although with low lethality, the expressive frequency of AVL in the State of Alagoas was still verified, since there was an increase in the number of cases during the years of the study.

No Brasil, a leishmaniose visceral americana (LVA) tornou-se uma preocupação de saúde pública devido à sua alta incidência e letalidade. Este estudo teve como objetivo analisar os aspectos clínicos, epidemiológicos e laboratoriais da AVL em um estado brasileiro. Este estudo descritivo, transversal, retrospectivo e quantitativo dos casos notificados de AVL foi realizado em Alagoas entre 2008 e 2017 a partir de dados obtidos do DATASUS/SINAN. Foram analisadas variáveis sociodemográficas, clínicas e laboratoriais. Foi realizada uma análise descritiva utilizando-se valores absolutos e percentuais válidos, utilizando tabelas e/ou gráficos. O processamento dos dados foi realizado por meio do Stata 12.0®. Os resultados com P<0,05 foram considerados estatisticamente significativos. Durante o período de estudo, foram notificados 352 casos de LVA, dos quais 6,82% morreram e 38,92% atenderam a um critério de cura. Os pacientes do sexo masculino foram predominantes (66,76%). Do total de pacientes infectados, 16,76% tinham sido atendidos apenas do 1º ao 4º ano, com os mais afetados entre 1 e 4 anos (28,69%). Os critérios de diagnóstico laboratorial foram mais utilizados para confirmar os casos notificados (76,42%), enquanto 51,70% e 8,52% dos casos apresentaram diagnósticos positivos parasitológicos e imunofluorescência, respectivamente. Por fim, o estudo demonstrou maior prevalência da doença em crianças, homens e nos residentes em zona rural. Embora com letalidade baixa, constatou-se ainda a expressiva frequência da LVA no Estado de Alagoas, uma vez que houve aumento do número de casos durante os anos do estudo.

American visceral leishmaniasis in a state of northeastern Brazil: clinical, epidemiological and laboratory aspects

Abstract In Brazil, American visceral leishmaniasis (AVL) has become a public health concern due to its high incidence and lethality. This study aimed to analyze the clinical, epidemiological, and laboratory aspects of AVL in a state of Brazil. This descriptive, cross-sectional, retrospective, and quantitative study of notified cases of AVL was carried out in Alagoas between 2008 and 2017 from data obtained from DATASUS/SINAN. Sociodemographic, clinical, and laboratory variables were analyzed. A descriptive analysis was performed using absolute values and valid percentages, using tables and/or graphs. Data processing was performed using Stata 12.0®. Results with P 0.05 were considered statistically significant. During the study period, 352 cases of AVL were reported, of which 6.82% died and 38.92% had met a cure criterion. Male patients were predominant (66.76%). Of the total infected patients, 16.76% had attended only the 1st to the 4th grades, with those most affected aged 1 to 4 years (28.69%). Laboratory diagnostic criteria were most commonly used to confirm the notified cases (76.42%), whereas 51.70% and 8.52% of the cases had positive parasitological and immunofluorescence diagnoses, respectively. Finally, the study showed a higher prevalence of the disease in children, men and in rural residents. Although with low lethality, the expressive frequency of AVL in the State of Alagoas was still verified, since there was an increase in the number of cases during the years of the study.

Resumo No Brasil, a leishmaniose visceral americana (LVA) tornou-se uma preocupação de saúde pública devido à sua alta incidência e letalidade. Este estudo teve como objetivo analisar os aspectos clínicos, epidemiológicos e laboratoriais da AVL em um estado brasileiro. Este estudo descritivo, transversal, retrospectivo e quantitativo dos casos notificados de AVL foi realizado em Alagoas entre 2008 e 2017 a partir de dados obtidos do DATASUS/SINAN. Foram analisadas variáveis sociodemográficas, clínicas e laboratoriais. Foi realizada uma análise descritiva utilizando-se valores absolutos e percentuais válidos, utilizando tabelas e/ou gráficos. O processamento dos dados foi realizado por meio do Stata 12.0®. Os resultados com P 0,05 foram considerados estatisticamente significativos. Durante o período de estudo, foram notificados 352 casos de LVA, dos quais 6,82% morreram e 38,92% atenderam a um critério de cura. Os pacientes do sexo masculino foram predominantes (66,76%). Do total de pacientes infectados, 16,76% tinham sido atendidos apenas do 1º ao 4º ano, com os mais afetados entre 1 e 4 anos (28,69%). Os critérios de diagnóstico laboratorial foram mais utilizados para confirmar os casos notificados (76,42%), enquanto 51,70% e 8,52% dos casos apresentaram diagnósticos positivos parasitológicos e imunofluorescência, respectivamente. Por fim, o estudo demonstrou maior prevalência da doença em crianças, homens e nos residentes em zona rural. Embora com letalidade baixa, constatou-se ainda a expressiva frequência da LVA no Estado de Alagoas, uma vez que houve aumento do número de casos durante os anos do estudo.

American visceral leishmaniasis in a state of northeastern Brazil: clinical, epidemiological and laboratory aspects / Leishmaniose visceral americana em estado do nordeste brasileiro: aspectos clínicos, epidemiológicos e laboratoriais

In Brazil, American visceral leishmaniasis (AVL) has become a public health concern due to its high incidence and lethality. This study aimed to analyze the clinical, epidemiological, and laboratory aspects of AVL in a state of Brazil. This descriptive, cross-sectional, retrospective, and quantitative study of notified cases of AVL was carried out in Alagoas between 2008 and 2017 from data obtained from DATASUS/SINAN. Sociodemographic, clinical, and laboratory variables were analyzed. A descriptive analysis was performed using absolute values and valid percentages, using tables and/or graphs. Data processing was performed using Stata 12.0®. Results with P <0.05 were considered statistically significant. During the study period, 352 cases of AVL were reported, of which 6.82% died and 38.92% had met a cure criterion. Male patients were predominant (66.76%). Of the total infected patients, 16.76% had attended only the 1st to the 4th grades, with those most affected aged 1 to 4 years (28.69%). Laboratory diagnostic criteria were most commonly used to confirm the notified cases (76.42%), whereas 51.70% and 8.52% of the cases had positive parasitological and immunofluorescence diagnoses, respectively. Finally, the study showed a higher prevalence of the disease in children, men and in rural residents. Although with low lethality, the expressive frequency of AVL in the State of Alagoas was still verified, since there was an increase in the number of cases during the years of the study.

No Brasil, a leishmaniose visceral americana (LVA) tornou-se uma preocupação de saúde pública devido à sua alta incidência e letalidade. Este estudo teve como objetivo analisar os aspectos clínicos, epidemiológicos e laboratoriais da AVL em um estado brasileiro. Este estudo descritivo, transversal, retrospectivo e quantitativo dos casos notificados de AVL foi realizado em Alagoas entre 2008 e 2017 a partir de dados obtidos do DATASUS/SINAN. Foram analisadas variáveis sociodemográficas, clínicas e laboratoriais. Foi realizada uma análise descritiva utilizando-se valores absolutos e percentuais válidos, utilizando tabelas e/ou gráficos. O processamento dos dados foi realizado por meio do Stata 12.0®. Os resultados com P<0,05 foram considerados estatisticamente significativos. Durante o período de estudo, foram notificados 352 casos de LVA, dos quais 6,82% morreram e 38,92% atenderam a um critério de cura. Os pacientes do sexo masculino foram predominantes (66,76%). Do total de pacientes infectados, 16,76% tinham sido atendidos apenas do 1º ao 4º ano, com os mais afetados entre 1 e 4 anos (28,69%). Os critérios de diagnóstico laboratorial foram mais utilizados para confirmar os casos notificados (76,42%), enquanto 51,70% e 8,52% dos casos apresentaram diagnósticos positivos parasitológicos e imunofluorescência, respectivamente. Por fim, o estudo demonstrou maior prevalência da doença em crianças, homens e nos residentes em zona rural. Embora com letalidade baixa, constatou-se ainda a expressiva frequência da LVA no Estado de Alagoas, uma vez que houve aumento do número de casos durante os anos do estudo.

American visceral leishmaniasis in a state of northeastern Brazil: clinical, epidemiological and laboratory aspects.

In Brazil, American visceral leishmaniasis (AVL) has become a public health concern due to its high incidence and lethality. This study aimed to analyze the clinical, epidemiological, and laboratory aspects of AVL in a state of Brazil. This descriptive, cross-sectional, retrospective, and quantitative study of notified cases of AVL was carried out in Alagoas between 2008 and 2017 from data obtained from DATASUS/SINAN. Sociodemographic, clinical, and laboratory variables were analyzed. A descriptive analysis was performed using absolute values ​​and valid percentages, using tables and/or graphs. Data processing was performed using Stata 12.0®. Results with P <0.05 were considered statistically significant. During the study period, 352 cases of AVL were reported, of which 6.82% died and 38.92% had met a cure criterion. Male patients were predominant (66.76%). Of the total infected patients, 16.76% had attended only the 1st to the 4th grades, with those most affected aged 1 to 4 years (28.69%). Laboratory diagnostic criteria were most commonly used to confirm the notified cases (76.42%), whereas 51.70% and 8.52% of the cases had positive parasitological and immunofluorescence diagnoses, respectively. Finally, the study showed a higher prevalence of the disease in children, men and in rural residents. Although with low lethality, the expressive frequency of AVL in the State of Alagoas was still verified, since there was an increase in the number of cases during the years of the study.

Antibacterial effects of the lectin from pomegranate sarcotesta (PgTeL) against Listeria monocytogenes.

AIMS: To investigate the effects of the lectin from Punica granatum sarcotesta (PgTeL) on growth, viability, cell structure, biofilm formation and chitinase activity of Listeria monocytogenes. In addition, the effect of PgTeL on the adhesion and invasion of human cells (HeLa) was determined. METHODS AND RESULTS: PgTeL showed bacteriostatic and bactericidal effects on the strains L. monocytogenes N53-1 and EGD-e, causing morphometric alterations, cell aggregation, strong deformation and cell disruption. PgTeL inhibited biofilm formation by EGD-e and N53-1 and also interfered with the adhesion and invasion processes of EGD-e and N53-1 in HeLa cells. Finally, the chitinase activity of L. monocytogenes EGD-e was reduced in the presence of PgTeL, which can be involved in the inhibition of adhesion process. CONCLUSION: PgTeL is an antibacterial agent against L. monocytogenes, inhibiting growth and promoting cell death, as well as impairing biofilm formation and bacterial adhesion and invasion into human cells. SIGNIFICANCE AND IMPACT OF THE STUDY: The results stimulate future investigations on the potential of PgTeL for protection of contamination in food products.

Barbatic acid from Cladia aggregata (lichen): Cytotoxicity and in vitro schistosomicidal evaluation and ultrastructural analysis against adult worms of Schistosoma mansoni.

Schistosomiasis is one of the most significant neglected tropical diseases, affecting around 260 million people worldwide, and Praziquantel is currently the only available drug for the treatment of infected persons. Thus, the search for new schistosomicidal compounds is urgent. The objective of this study was to investigate of the schistosomicidal effect of barbatic acid, a lichen metabolite, on adult worms of Schistosoma mansoni. The in vitro schistosomicidal effect was evaluated through the assessment of motility and mortality, cellular viability of the worms and ultrastructural analysis through scanning electron microscopy. To evaluate the cytotoxicity of barbatic acid, a cell viability assay was performed with human peripheral blood mononuclear cells. Barbatic acid showed a schistosomicidal effect after 3 h of exposure. At the end of 24 h the concentrations of 50-200 µM presented lethality on the worms. Motility changes were observed at sublethal concentrations. The IC50 obtained by the cell viability assay for S. mansoni was 99.43 µM. Extensive damage to the worm's tegument was observed from 25 µM. No cytotoxicity was observed on human peripheral blood mononuclear cells. This report provides data showing the schistosomicidal effect of barbatic acid on S. mansoni, causing death, motility changes and ultrastructural damage to worms. In addition, barbatic acid was shown to be non-toxic to human peripheral blood mononuclear cells at concentrations that are effective against S. mansoni.

Hemocytes of the Rose Sawfly Arge ochropus (Gmelin) (Hymenoptera: Argidae).

We characterized individual morphological types of the rose sawfly, Arge ochropus (Gmelin) (Hymenoptera: Argidae), hemocytes for the first time by means of light and differential interference contrast microscopy and scanning and transmission electron microscopy. Four types of hemocytes were identified in the hemolymph of larvae and pupae of A. ochropus: prohemocytes, plasmatocytes, granulocytes, and oenocytoids. Prohemocytes are the smallest type of hemocytes, rounded to ovoid cells with large nuclei. Plasmatocytes are polymorphic and variable in size. Granulocytes are oval and spherical cells variable in size, with variable number of rough endoplasmic reticulum, mitochondria, and microtubules in the cytoplasm. Oenocytoids contain eccentric nucleus and cytoplasm with small mitochondria and few rough endoplasmic reticula. Differential hemocyte counts indicated that plasmatocytes are the most abundant hemocyte type during early instars while granulocytes are the most abundant hemocyte type in the last instar. The pattern of total hemocyte count changed during rose sawfly development and reached its peak in prepupae and then declined slowly in the pupal stage.

Hemocytes of Rhipicephalus sanguineus (Acari: Ixodidae): Characterization, Population Abundance, and Ultrastructural Changes Following Challenge with Leishmania infantum.

Few studies have examined the cellular immune response of ticks, and further research on the characterization of the hemocytes of ticks is required, particularly on those of Rhipicephalus sanguineus (Latreille) because of the medical and veterinary importance of this tick. The aims of this study were to characterize the morphology and the ultrastructure of the different types of hemocytes of adult R. sanguineus and to determine the population abundance and the ultrastructural changes in the hemocytes of ticks infected with Leishmania infantum. The hemocytes were characterized through light and transmission electron microscopy. Within the variability of circulating cells in the hemolymph of adult R. sanguineus, five cell types were identified, which were the prohemocytes, plasmatocytes, granulocytes, spherulocytes, and adipohemocytes. The prohemocytes were the smallest cells found in the hemolymph. The plasmatocytes had polymorphic morphology with vesicles and cytoplasmic projections. The granulocytes had an elliptical shape with the cytoplasm filled with granules of different sizes and electrodensities. The spherulocytes were characterized by several spherules of uniform shapes and sizes that filled the entire cytoplasm, whereas the adipohemocytes had an irregular shape with multiple lipid inclusions that occupied almost the entire cytoplasmic space. The total counts of the hemocyte population increased in the group that was infected with L. infantum. Among the different cell types, the numbers increased and the ultrastructural changes occurred in the granulocytes and the plasmatocytes in the infected group of ticks.

Characterization of the bacterial microbiota of Biomphalaria glabrata (Say, 1818) (Mollusca: Gastropoda) from Brazil.

UNLABELLED: Roughly 200 000 000 people in 74 countries infected with schistosomes all share the fact that they came in contact freshwater harbouring infected snails. The aim of the study is to characterize the microbiota of wild and laboratory-reared snails of Biomphalaria glabrata from Pernambuco, Brazil. The microbiota of these molluscs was identified biochemically by the VITEK 2 automated microbiological system. Antimicrobial susceptibility testing was carried out by the disc diffusion method with ß-lactam antibiotics, aminoglycosides, quinolones, folate pathway inhibitors, fenicols and tetracyclines. The results showed that all bacteria identified were gram-negative, including 11 bacterial genera: Aeromonas, Citrobacter, Enterobacter, Cupriavidus, Rhizobium, Stenotrophomonas, Pseudomonas, Klebsiella, Acinetobacter, Vibrio and Sphingomonas. Regarding the antimicrobial susceptibility, all the isolates exhibited resistance to amoxicillin and sensitivity to meropenem (beta-lactam antimicrobials). The microbiota of the wild snails consisted predominantly of Enterobacter cloacae, while the laboratory-reared snails predominantly showed Citrobacter freundii and Aeromonas sobria. SIGNIFICANCE AND IMPACT OF THE STUDY: Biomphalaria glabrata is a Brazilian freshwater Planorbidae of great medical relevance as an intermediate host of Schistosoma mansoni. About a month after being infected by one or more miracidia larvae of a compatible schistosome, B. glabrata sheds thousands of cercariae into the water where they seek human skin and, if successful, penetrate to establish infection, eventually taking up residence and maturing in blood vessels of the small intestine. Results obtained from this study aim at targeting novel biological control strategies for schistosomiasis such as paratransgenesis. This is the first study on the microbiota of B. glabrata from Brazil.

Morphological characterization of hemocytes from Biomphalaria glabrata and Biomphalaria straminea.

Biomphalaria glabrata and Biomphalaria straminea have been identified as intermediate hosts for Schistosoma mansoni. Several studies have found two cell types in the hemolymph of B. glabrata (hyalinocytes and granulocytes). However, there are no studies describing the hemocytes of B. straminea. With the aim of further describing the hemocyte subsets in B. glabrata and B. straminea, we conducted a detailed study using optical microscopy and transmission electron microscopy. Based on the morphological characteristics of the cells, we identified the same types of hemocytes in two species of molluscs, namely: blast-like cells, granulocytes, type I hyalinocytes, type II hyalinocytes and type III hyalinocytes. Blast-like cells had a spherical profile with a central nucleus filling almost the whole cell. Granulocytes were characterized by presenting variable numbers of granules. Type I hyalinocytes were the most abundant cell type and displayed various cytoplasmic projections. Type II and type III hyalinocytes had never previously been reported. They were few in number and were characterized by having an eccentric nucleus. From these results, it is concluded that there are five types of cells in the hemolymph of B. glabrata and B. straminea. Further studies are now needed to identify the role of these hemocytes in the immune response of these snails.

Ultrastructural analysis of microfilariae of Wuchereria bancrofti obtained from persistent carriers after repeated courses of diethylcarbamazine.

Single dose of diethylcarbamazine (DEC) used in control programs is effective in breaking the transmission of filariasis. In order to investigate the effect of aggressive therapy on Wuchereria bancrofti (Wb) microfilariae, DEC was given to 29 patients who were positive for the circulating filarial antigen (CFA) assay but did not have clinical manifestations of filariasis, at 6 mg/kg/day for 12 days and again six months later using the same dosing regimen. For each patient, microfilarial density and serum CFA were followed up for two years. Ultrastructural analyses on Wb microfilariae obtained after repeated treatment with DEC were also performed. Microfilaremia and antigenemia decreased significantly after 12 months but returned to the initial levels after 24 months. This could indicate, as shown by other authors, that aggressive repeated therapy with DEC alone is ineffective in eradicating adult W. bancrofti, particularly in infected but asymptomatic individuals. The objective of the present study was to analyze the microfilaremic and antigenemic behavior and ultrastructural changes caused by different DEC concentrations in vitro in Wb microfilariae obtained from individuals who were sensitive and refractory to treatment. After in vitro treatment of the microfilariae using 5 and 10 microg/ml of DEC for 1h, ultrastructural analysis revealed low levels of cell damage compared with embryos obtained from individuals from a different area who had never received DEC treatment before. The results obtained suggest that microfilariae from patients who receive repeated aggressive therapy are less sensitive to DEC in vitro.

Ultrastructural and cytochemical aspects of Schistosoma mansoni cercaria.

An alternative to identify the critical processes necessary to the parasite establishment of the host is to focus on the evolutionary stage responsible for the primary invasion, i.e. the infection structure. The objective of this study was to ultrastructurally characterize Schistosoma mansoni cercariae, using cytochemical techniques. In order to identify basic proteins, techniques such as ethanolic phosphotungstic acid (EPTA) and ammoniacal silver staining were used. Calcium sites location was achieved using the Hepler technique and to evidence anionic groups, we used cationic ferritin particles and enzyme treatment with trypsin Vibrio cholerae, chondroitinase and neuraminidase. The EPTA technique highlighted the presence of basic tegument proteins, nucleus and nucleolus from subtegumental cells, inclusion bodies and preacetabular glands. After using ammoniacal silver, we observed a strong staining in all infective larvae, particularly in the nuclei of muscle cells, circular muscle tissue and preacetabular glands. Calcium site locations were shown to be uniform, thereby limiting the inner spaces of the larvae, especially muscle cells. Samples treated with cationized ferritin particles presented strong staining at the cuticular level. Neuraminidase treatment did not alter the stained shape of such particles on the trematode surface. However, trypsin or chondroitinase treatment resulted in absence of staining on the larval surface. This information on the biochemical composition of the infecting S. mansoni larvae provides data for a better understanding of the biology of this parasite and background on the intriguing parasite-host relationship.

Hemocytes ultrastructure of Aedes aegypti (Diptera: Culicidae).

Mosquitoes have an efficient defence system against infection. Insect blood cells (hemocytes) play an essential role in defense against parasites and other pathogenic organisms that infect insects. We have identified by light and transmission electron microscopy six hemocytes cell types from the hemolymph of Aedes aegypti. They were: prohemocytes (20%), adipohemocytes (29%), granulocytes (16%), plasmatocytes (27%), oenocytoids (7%) and thrombocytoids (0.9%). The prohemocytes were the smallest hemocytes found in the hemolymph. Its cytoplasm occupies only a narrow area around the nucleus. The adipohemocytes were the most abundant cell type presented. These hemocytes exhibited a large lipid like vesicle and mitochondria. In electron micrographs, the granulocytes showed cytoplasm containing dilated rough endoplasmic reticulum (RER) and a round or elongated mitochondria. Electron-dense granules with a proteinaceous material were also present. The plasmatocytes were polymorphic and exhibited plasma membrane with irregular processes, philopodia and pseudopodia. Ultrastructural investigation revealed that the reticular cytoplasm showed a well-developed RER, a Golgi and vacuoles. Oenocytoids showed homogeneous cytoplasm with many mitochondria and ribosomes are scattered throughout the cytoplasm, abundant RER and a small smooth endoplasmic reticulum (SER) present at the cell poles. Thrombocytoids were very fragile and few in number. Similar characteristics were found in oenocytoids, possessing a homogeneous cytoplasm with poorly developed organelles, few mitochondria and granules.