Eco-epidemiologia de Haemonchus contortus bahienses, ecotipo presente en ovinos de zonas aridas de Venezuela

Haemonchus contortus bahiensis Grisi, 1974 parasita a los ovinos de zonas áridas de Venezuela. En las hembras de dicho ecotipo la distribución de frecuencias por nosotros observada fue de un 15,32% para el morfotipo con lengüeta supravulvar, de un 51,61% para el botonado y de un 33,07% para el liso. Correspondiéndole a dicho ecotipo un índice de diversidad de Shannon-Weaver de 1,44 bits. Las medidas corporales, el tamaño de los huevos y el symlophe son similares en los tres morfotipos. La disposición espacial tanto de los machos como de las hembras en el seno de la población de hospedadores es de tipo contagiosa siendo bien descrita por el parámetro K de la distibución binominal negativa. Se evidenció la existencia de una compleja interacción entre la abundancia, la agregación y la prevalencia de dicho ecotipo y se discute su importancia sobre el equilibrio hospedador-parásito.

The dermal leishmaniases of Brazil, with special reference to the eco-epidemiology of the disease in Amazonia

Six species of Leishmania are at present known to cause cutaneous and/or mucocutaneous leishamniasis in Brazil, and they are all to be found in the Amazon region of this country. The eco-epidemiology of each is discussed, with the observation that the Amazonian leishmaniases are all zoonoses, with their source in silvatic mammals and phlebotomine sandfly vectors. With man's destruction of the natural forest in southern Brazil, some sandfly species have survived by adapting to a peridomestic or domiciliary habitat in rural areas. Some domestic animals, such as dogs and equines are seemingly now involved in the epidemiology of the disease. No such process has yet been reported in the Amazon region, but may well take place with the continuing devastation of its forest.

American cutaneous leishmaniasis in Pernambuco, Brazil: eco-epidemiological aspects in "Zona da Mata" region

American cutaneous leishmaniasis (ACL) has been increasing in Pernambuco, thus becoming an important problem for Public Health. The incindence is predominant in the region called "Zona da Mata", in the east of this state. This region corresponds geographically to the primitive area of the Atlantic forest. In order to characterize the eco-epidemiology expression of ACL in this region, two localities situated in the municipalities of Amaraji e Cortes have been selected by the criterion of higher incindence of human cases. Five stocks of patients were characterized and identified on the basis of enzyme profiles as a new variant of Leishmania (V.) braziliensis. A survey of wild and domestic animals was carried out by means of a parasitological and serological diagnosis. Through the analysis of the spleen and liver imprints, were detected amastigotes compatible with Leishmania in five Nectomys s. squamipes, five Bolomys l. pixuna, two Rattus r. alexandrinus and one Rattus r. frugivorus. For two years we carried out monthly sandflies captures using CDC light traps as well as manual captures. Lutzomyia whitmani was predominant, which accounted for 97.4 por cento of the total. These data indicate a strong evidence on the vector and the potential reservoirs of L. braziliensis in this region.

Lutzomyia longipalpis and the eco-epidemiology of American visceral leishmaniasis, with particular reference to Brazil: a review

An historical review is given of American visceral leishmaniasis (AVL), with particular reference to the eco-epidemiology of the disease in Brazil. Following the first records of AVL in this country, in 1934, the sandfly Lutzomyia longipalpis (Lutz and Neiva, 1912) was incriminated as the principal vector. It is now generally accepted, however, that there exist a number of cryptic species under the name of Lu. longipalpis s.l. and that variations in the quantity of the vasodilatory peptide maxadilan in the saliva of flies from different populations of Lu. longipalpis s.l., may account for the variable clinical manifestations of AVL seen in different geographic regions. Distribution of AVL has been shown to extend throughout most of South and Central America, with the domestic dog serving as the principal reservoir of infection for man. However, while one hypothesis suggests that the causative parasite is Leishmania infantum, imported from Europe with the Portuguese and Spanish colonists, the demonstration of a high rate of benign, inapparent infection in foxes in Amazonian Brazil raised an opposing suggestion that the parasite is indigenous to the Americas. Recent reports of similar infections in native marsupials, and possibly rodents, tend to support this view, particularly as Lu. longipalpis is primordially a silvatic sandfly. Although effective control measures in foci of the disease will diminish the number of canine and human infections, the presence of such an enzootic in a variety of native animals will render the total eradication of AVL unlikely.

More productive in vitro culture of Cryptosporidium parvum for better study of the intra- and extracellular phases

The great difficulties in treating people and animals suffering from cryptosporidiosis have prompted the development of in vitro experimental models. Due to the models of in vitro culture, new extracellular stages of Cryptosporidium have been demonstrated. The development of these extracellular phases depends on the technique of in vitro culture and on the species and genotype of Cryptosporidium used. Here, we undertake the molecular characterization by polymerase chain reaction-restriction fragment lenght polymorphism of different Cryptosporidium isolates from calves, concluding that all are C. parvum of cattle genotype, although differing in the nucleotide at positions 472 and 498. Using these parasites, modified the in vitro culture technique for HCT-8 cells achieving greater multiplication of parasites. The HCT-8 cell cultures, for which the culture had not been renewed in seven days, were infected with C. parvum sporozoites in RPMI-1640 medium with 10% IFBS, CaCl2 and MgCl2 1 mM at pH 7.2. Percentages of cell parasitism were increased with respect to control cultures (71% at 48 h vs 14.5%), even after two weeks (47% vs 1.9%). Also, the percentage of extracellular stages augmented (25.3% vs 1.1% at 96 h). This new model of in vitro culture of C. parvum will enable easier study of the developmental phases of C. parvum in performing new chemotherapeutic assays.

Molecular approaches for eco-epidemiological studies of Paracoccidioides brasiliensis

Medical mycology has greatly benefited from the introduction of molecular techniques. New knowledge on molecular genetics has provided both theoretical and practical frameworks, permitting important advances in our understanding of several aspects of pathogenic fungi. Considering Paracoccidioides brasiliensis in particular, important eco-epidemiological aspects, such as environmental distribution and new hosts were clarified through molecular approaches. These methodologies also contributed to a better understanding about the genetic variability of this pathogen; thus, P. brasiliensis is now assumed to represent a species complex. The present review focuses on some recent findings about the current taxonomic status of P. brasiliensis, its phylogenetic and speciation processes, as well as on some practical applications for the molecular detection of this pathogen in environmental and clinical materials.

Bromeliad-inhabiting mosquitoes in an urban botanical garden of dengue endemic Rio de Janeiro - Are bromeliads productive habitats for the invasive vectors Aedes aegypti and Aedes albopictus?

Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus(0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats.

New scenarios of Trypanosoma cruzi transmission in the Orinoco region of Colombia

Rhodnius prolixus, a blood-sucking triatomine with domiciliary anthropophilic habits, is the main vector of Chagas disease. The current paradigm of Trypanosoma cruzi transmission in Columbia includes a sylvatic and domiciliary cycle co-existing with domestic and sylvatic populations of reservoirs. The aim of this study is to evaluate the population densities and relative abundance of triatomines and mammals that may be involved in the sylvatic cycle of Chagas disease to clarify the epidemiological scenario in an endemic area in the province of Casanare. Insect vectors on Attalea butyracea palms were captured using both manual searches and bait traps. The capture of mammals was performed using Sherman and Tomahawk traps. We report an infestation index of 88.5% in 148 palms and an index of T. cruzi natural infection of 60.2% in 269 dissected insects and 11.9% in 160 captured mammals. High population densities of triatomines were observed in the sylvatic environment and there was a high relative abundance of reservoirs in the area, suggesting a stable enzootic cycle. We found no evidence of insect domiciliation. Taken together, these observations suggest that eco-epidemiological factors shape the transmission dynamics of T. cruzi, creating diverse scenarios of disease transmission.

Biotechnology applied to Annona species: a review

Annonaceae is an ancient family of plants including approximately 50 genera growing worldwide in a quite restricted area with specific agroclimatic requirements. Only few species of this family has been cultivated and exploited commercially and most of them belonging to the genus Annona such as A. muricata, A. squamosa, the hybrid A. cherimola x A. squamosa and specially Annona cherimola: the cherimoya, commercially cultivated in Spain, Chile, California, Florida, México, Australia, Ecuador, Peru, Brazil, New Zealand and several countries in South and Central America. The cherimoya shows a high degree of heterozygosis, and to obtain homogeneous and productive orchards it is necessary to avoid the propagation by seeds of this species. Additionally, the traditional methods of vegetative propagation were inefficient and inadequate, due to the low morphogenetic potential of this species, and the low rooting rate. The in vitro tissue culture methods of micropropagation can be applied successfully to cherimoya and other Annona sp to overcome these problems. Most of the protocols of micropropagation and regeneration were developed using the cultivar Fino de Jete, which is the major cultivar in Spain. First it is developed the method to micropropagate the juvenile material of cherimoya (ENCINA et al., 1994), and later it was optimized a protocol to micropropagate adult cherimoya genotypes selected by outstanding agronomical traits (PADILLA and ENCINA, 2004) and further it was improved the process through micrografting (PADILLA and ENCINA, 2011).At the present time we are involved in inducing and obtaining new elite genotypes, as part of a breeding program for the cherimoya and other Annonas, using and optimizing different methodologies in vitro: a) Adventitious organogenesis and regeneration from cellular cultures (ENCINA, 2004), b) Ploidy manipulation of the cherimoya, to obtain haploid, tetraploid and triploid plants (seedless), c) Genetic transformation, for the genes introduction to control the postharvest processes and the genes introduction to provide resistance to pathogen and insects and d) Micropropagation and regeneration of other wild Annona or related Annonaceae species such as: Annona senegalensis, A. scleroderma, A. montana, A. reticulata, A. glabra, A. diversifolia and Rollinia sp.

STUDY ON THE SUGAR-ACID RATIO AND RELEVANT METABOLIZING ENZYME ACTIVITIES IN NAVEL ORANGE FRUITS FROM DIFFERENT ECO-REGIONS

ABSTRACT The flavor quality of citrus fruits is largely determined by the sugar-acid ratio, but it remains uncertain how sugar- and/or acid-metabolizing enzymes regulate the sugar-acid ratio of navel oranges and further affect the fruit quality. In the present study, Robertson navel oranges (Citrus sinesis Osb.) were collected from six representative habitats in three eco-regions of Sichuan, China. The changes in the sugar-acid ratio and the activities of sucrose phosphate synthase (SPS), sucrose synthase (SS), cytosolic cio-aconitase (ACO), and isocitrate dehydrogenase (IDH) were examined in navel oranges during fruit development. The results indicated that the sugar-acid ratio of fruits in different eco-regions changed significantly from 150 days after full bloom. The SPS and cytosolic ACO fruit activities had minor changes among different ecoregions throughout the experimental periods, whereas the activities of SS and IDH changed significantly in fruits among three eco-regions. Furthermore, the sugar-acid ratio and the activities of SS in the synthetic direction and IDH were the highest in south subtropics and the lowest in north mid-subtropics, probably due to the effects of climate conditions and/or other relevant eco-factors. It demonstrated that SS in the synthetic direction and IDH were of greater importance in regulating the sugar-acid ratio of navel oranges in different eco-regions, which provided new insights into the factors that determine the flavor quality of navel oranges and valuable data for guiding relevant agricultural practices.

Estudo comparativo entre marcadores ultra-sonográficos morfológicos preditores de parto pré-termo: sinal do afunilamento do colo e ausência do eco glandular endocervical

OBJETIVO: Avaliar o risco de parto pré-termo (PPT) espontâneo na população geral a partir do estudo comparativo dos marcadores ultra-sonográficos morfológicos do colo uterino, como o sinal do afunilamento e a ausência da área glandular endocervical. MATERIAIS E MÉTODOS: Foram arroladas 361 gestantes na população geral, submetidas a exame ultra-sonográfico transvaginal entre a 21ª e 24ª semana, e verificados os resultados perinatais. RESULTADOS: A incidência de PPT espontâneo foi de 5,0%. O sinal do afunilamento foi observado em 4,2% da população estudada e em 22,2% das pacientes que evoluíram para PPT espontâneo. Tal parâmetro mostrou associação significante com PPT (p < 0,001; risco relativo de 6,68). A ausência do eco glandular endocervical (EGE) foi detectada em 2,8% das pacientes estudadas e em 44,4% das pacientes que evoluíram para PPT espontâneo. Este parâmetro demonstrou forte associação com PPT espontâneo (p < 0,001; risco relativo de 28,57). A análise de regressão logística multivariada apontou a ausência do EGE como a única variável morfológica associada ao PPT espontâneo. CONCLUSÃO: A predição do PPT espontâneo a partir de sinais ultra-sonográficos deve ser realizada contemplando marcadores biométricos e morfológicos, entre estes, a ausência do EGE. Este estudo indica uma tendência clara da marcante importância da ausência do EGE como indicador do risco para PPT espontâneo, a ser confirmada futuramente em pesquisas multicêntricas.

Diferenciação entre cisto simples e hemangioma hepático utilizando seqüência de ressonância magnética ponderada em T2 com técnica gradiente-eco (B-FFE)

OBJETIVO: Estabelecer o valor das seqüências ponderadas em T2 para diferenciar cistos simples de hemangiomas hepáticos. MATERIAIS E MÉTODOS: Estudo prospectivo, observacional, transversal e duplo-cego em 52 pacientes com 91 lesões hepáticas (34 cistos simples e 57 hemangiomas) submetidos a ressonância magnética de abdome. A análise conjunta de todas as seqüências realizadas foi considerada o padrão-ouro. Dois observadores independentes avaliaram, subjetivamente, as seqüências TSE com TE longo e B-FFE, procurando diferenciar cistos de hemangiomas. Foram calculadas a eficácia das seqüências e a concordância interobservador e intra-observador por meio do teste kappa (κ) (p < 0,05*). RESULTADOS: As dimensões dos cistos variaram entre 0,5 e 6,5 cm (média de 1,89 cm) e as dos hemangiomas, entre 0,8 e 11 cm (média de 2,62 cm). A concordância entre a avaliação da seqüência com TE longo e o padrão-ouro foi insignificante (κ: 0,00-0,10). A concordância entre a avaliação da seqüência B-FFE e o padrão-ouro variou de substancial (κ: 0,62-0,71) a quase perfeita (κ: 0,86) para ambos os examinadores. A concordância interobservador e intra-observador para a seqüência B-FFE variou entre substancial (κ: 0,62-0,70) e quase perfeita (κ: 0,85-0,91). CONCLUSÃO: A técnica B-FFE apresenta eficácia e reprodutibilidade elevadas na diferenciação de cistos e hemangiomas.