Comparative study of four species of Trichuris roederer, 1761 (Nematoda, Trichurinae) by scanning electron microscopy

A comparative morphological study of Trichuris travassosi, T. vulpis, T. discolor and T. suis was perfomed using scanning electron microscopy. Cuticular inflation associated with the bacillar band, vulva and male external genital appendages were analyzed. Qualitative and quantitative analyses of these structures were made for each species; they are of taxonomic value.

Description of the fourth instar larva of Lutzomyia longipalpis, under scanning electron microscopy

The fourth instar larva of Lutzomyia (Lutzomyia) longipalpis (Phlebotomidae: Phlebotominae) was studied by scanning electron microscope. Based on three-dimensional observations, the fine structure and setal position (using of setal numeration) of the larva are presented.

Diagnostic Importance of Female External Genital Structure of Phlebotomine Sand Flies (Diptera:Psychodidae) as Observed by Scanning Electron Microscopy

Morphological description of sand flies has remained a neglected area. The different organs used in taxonomy have not yet been described adequately with the scanning electron microscopy (SEM). We have examined the external genital structures of females of three Old World phlebotomine sand flies under SEM and recorded the morphological variations of the organs. We have found the female external genital structures of the three species varied considerably in morphology. The importance of the female external genital structures in sand fly identification is indicated

Anopheles aquasalis Eggs from Two Venezuelan Localities Compared by Scanning Electron Microscopy

Anopheles (Nyssorhynchus) aquasalis, is the main coastal vector of malaria from northeastern Venezuela to southeastern Brazil. Several authors have argued that An. aquasalis is a highly polymorphic species while others indicated that it is a complex of closely related species. This investigation compared the morphology of An. aquasalis eggs from Sinamaica (Zulia State) and Yaguaraparo (Sucre State), the west and east of Venezuela, respectively. We were able to separate eggs from the two localities using discriminant analyses based on ratios and percentages of anterior and posterior tubercles measured by scanning electron microscopy. The results of this work suggest that An. aquasalis has high intraspecific variation

Update of the Gene Discovery Program in Schistosoma mansoni with the Expressed Sequence Tag Approach

Continuing the Schistosoma mansoni Genome Project 363 new templates were sequenced generating 205 more ESTs corresponding to 91 genes. Seventy four of these genes (81%) had not previously been described in S. mansoni. Among the newly discovered genes there are several of significant biological interest such as synaptophysin, NIFs-like and rho-GDP dissociation inhibitor

Morphological Study of Adult Male Worms of Schistosoma mansoni Sambon, 1907 by Scanning Electron Microscopy

Tubercles, spines and sensory receptors are the most studied structures of adult male worms of Schistosoma mansoni isolated in other countries. The purpose of this investigation was to properly define these structures in Brazilian worms. Specimens 7-8 weeks after infection were recovered from albino SW mice and from a wild rodent (Nectomys squamipes) and processed for scanning electron microscopy studies. Photomicrographs of the anterior region with the aspects related to the outer and inner regions of both suckers were considered. The ventral portion of the middle region was represented by the anterior of gynaecophoric canal while the dorsal surface was studied in its ventral and dorsal regions mainly focusing the aspect of the tubercles, spines and sensorial papillae. The outer surface of the oral sucker is spiny and spines are bigger, sharp with sensory receptors in their posterior edge. Tubercles with spines or receptors are more concentrated in the middle region and in one of the margins of the gynaecophoric canal. An excretory pore-like structure in the posterior portion was observed. The gynaecophoric canal has few sensory structures, spines broadned in their mid-region and are sharp pointed at the distal end. It was concluded that the presently studied characters are similar to those previously reported

Response to Heterologous Leishmanins in Cutaneous Leishmaniasis in Nigeria: Discovery of a New Focus

A pilot study was undertaken to preliminary illustrate the leishmanin skin test (LST) positivity to distinct antigen preparations (derived from promastigote of either Leishmania major or L. amazonensis, or pooled L. mexicana, L. amazonensis and L. guyanensis) in cutaneous leishmaniasis (CL) patients and healthy subjects living in two endemic foci in Nigeria. The study was designed to provide insights into whether cross-species leishmanin, such as that prepared from New World Leishmania could be useful to detect cases of Old World leishmanial infection and to compare the results with LST using L. major-derived leishmanin. The overall LST positivity in individuals from Keana tested with the cross-species leishmanin was 28.7% (27/94), while the positivity rate in the subjects from Kanana tested with the same leishmanin was 54.5% (6/11). Lower positivity values were obtained when L. major (12.5%; 11/88) or L. amazonensis (15.8%; 9/57) was tested as antigen in grossly comparable populations. Moreover, the pooled leishmanin identified most of the subjects (13/14; 92.9%) with active or healed CL, and the maximum reaction sizes were found among positive subjects in this group. No healthy controls (10 total) showed specific DTH response. The LST was useful for assessing the prevalence of subclinical infection and for measuring CL transmission over time. We report for the first time the occurrence of CL in Kanana village of Langtang South local government area of Plateau State

Scanning Electron Microscopy of Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae)

Lagochilascaris minor Leiper, 1909 is a parasitic nematode with its biological cycle still unknown, even though it was found in humans, domestic and silvatic animals. Adult worms, collected by surgical drainage from a human patient from the State of Pará, Brazil, were micrographed using a scanning electron microscope. Morphological aspects of males and females such as cephalic structures, caudal papillae and cuticular patterns were analyzed and compared with the previous descriptions adding new data for the identification of this species.

On a New Species of Hysterothylacium (Nematoda: Anisakidae) from Cauque mauleanum (Pisces: Atherinidae) by Brightfield and Scanning Electron Microscopy

Hysterothylacium geschei n. sp. (Nematoda, Anisakidae) is described from the intestine of Cauque mauleanum (Steindachner) (Pisces: Atherinidae) from Lake Panguipulli (39º43'S; 72º13'W), Chile. Eleven (78.6%) out of 14 fish were infected, with a mean intensity (range) of 14.4 (1-55) worms. The new species can be differentiated from the two previously described species of freshwater fishes from South America by the presence of lateral alae, the number of caudal papillae, and the length of the spicules, oesophagus, intestinal caecum, distance vulva-anterior extremity and the length ratio intestinal caecum: ventricular appendix. From the fishes examined in Lake Panguipulli, including the introduced salmonid species Oncorhynchus mykiss (Walbaum) and the authochthonous species Basilichthys australis Eigenmann (Atherinidae) and Percichthys trucha (Valenciennes) (Percichthyidae), only one specimen of P. trucha was found parasitized by a third-stage larva of this species.

Evolution of the clinical and epidemiological knowledge about Chagas disease 90 years after its discovery

Three different periods may be considered in the evolution of knowledge about the clinical and epidemiological aspects of Chagas disease since its discovery: (a) early period concerning the studies carried out by Carlos Chagas in Lassance with the collaboration of other investigators of the Manguinhos School. At that time the disease was described and the parasite, transmitters and reservoirs were studied. The coexistence of endemic goiter in the same region generated some confusion about the clinical forms of the disease; (b) second period involving uncertainty and the description of isolated cases, which lasted until the 1940 decade. Many acute cases were described during this period and the disease was recognized in many Latin American countries. Particularly important were the studies of the Argentine Mission of Regional Pathology Studies, which culminated with the description of the Romaña sign in the 1930 decade, facilitating the diagnosis of the early phase of the disease. However, the chronic phase, which was the most important, continued to be difficult to recognize; (c) period of consolidation of knowledge and recognition of the importance of Chagas disease. Studies conducted by Laranja, Dias and Nóbrega in Bambuí updated the description of Chagas heart disease made by Carlos Chagas and Eurico Villela. From then on, the disease was more easily recognized, especially with the emphasis on the use of a serologic diagnosis; (d) period of enlargement of knowledges on the disease. The studies on denervation conducted in Ribeirão Preto by Fritz Köberle starting in the 1950 decade led to a better understanding of the relations between Chagas disease and megaesophagus and other visceral megas detected in endemic areas.

Posterior spiracles of fourth instar larvae of four species of phlebotomine sand flies (Diptera: Psychodidae) under scanning electron microscopy

In the present study, posterior spiracles of laboratory-reared fourth instar larvae of Lutzomyia longipalpis, L. migonei, L. lenti, and L. whitmani (Diptera: Psychodidae) of the State of Ceará, Brazil, were examined under scanning electron microscopy. The number of papillae of spiracles examined varied according to the species examined, but no intraspecific differences were found. The importance of this structure to sand fly larva identification and phylogeny is commented.