Present aspects of immunodiagnosis of schistosomiasis

Facilitated and improved by advances in molecular biology, techniques for the immunodiagnosis of schistosomiasis, including assays based on the detection of antigens circulating in the serum and/or excreted in the urine, have now reached the stage of multi-centre trials. There is a need to complement parasitological techniques as some national programmes are becoming increasingly succesful in establishng control of the disease and the classical approach frequently fails to reveal low-intensity infection. Epidemiological survey teams in some areas have tentatively started to use serology and their experience indicates that antibody detection suffies in eradicated or controlled areas with low expected prevalence but that detection of circulating antigens is needed for assessment of the incidence of infection or reinfection in areas recently brought under control. Before reagents and procedures can be recommended for routine use of national control programmes, the assays must be standardized with sera from clinically well-characterized patients in geographically defined regions, hence emphasizing the need for a reference serum bank. Implementation of serological testing, carried out by nationsl public health laboratories using standardized testing systems, would permit valid comparisons between different areas providing support for decisions regarding national health polices.

Epidemiological aspects of American Cutaneous Leishmaniasis in a periurban area of the metropolitan region of Belo Horizonte, Minas Gerais, Brazil

In order to characterize the epidemiology of American Cutaneous Leishmaniasis (ACL) in a periurban area of the municipality of Sabará in the metropolitan region of Belo Horizonte (MRBH), an area until then considered free of the disease, a cross sectional survey was undertaken in 1990. The survey of the population consisted of 1119 interviews and 881 clinical examinations using Montenegro's skin test (MST). A low prevalence (3.7%) of positive MST was encountered. The disease had been occuring in the area for about 20 years in the form of sporadic cases. The predominant species of sandfly both in domestic areas and nearby areas of secondary vegetation was Lutzomyia whitmani. A canine survey of delayed hypersensitivity to the antigen P10,000 identified only one dog with a positive reaction out of 113 examined. The transmission of ACL in MRBH was confirmed. The occurrence of the disease in women, children and individuals with no contact with forest areas as well as the presence of potential vector species in the domiciliar environment, suggests the transmission of the disease in this environment.

Morphologic and morphometric aspects of oenocytes of Apis mellifera queens and workers in different phases of life

Oenocytes of adult workers and queens of Apis mellifera L. were studied in different ages or life stages, by means of morphometric and histologic techniques. In workers, the oenocytes were found in the head, near the mandibles and in the abdomen, immersed in the parietal fat body mainly below the sterna, close to the wax gland. In queens, two populations of oenocytes different in size and localization were found within the parietal and visceral fat body, respectively. The oenocytes of workers and queens show the presence of acid lipids and acid phosphatase. The role of these cells in the castes differences is discussed.

Ultrastructural aspects of virus replication in one fatal case and several other isolates from a dengue type 2 outbreak in Rio de Janeiro

Dengue virus replication in mosquito cell cultures was observed by electron microscopy in one fatal and 40 classical isolates from a dengue type 2 outbreak in Rio de Janeiro and compared with the prototype New Guinea C strain. All the Brazilian isolates presented, beside the classical structured dengue virus particles, fuzzy coated virus-like particles, never observed in thereferencial New Guinea C virus strain. more numerous DEN-2 virus particles, fuzzy coated virus-like particles, defective virus particles and smooth membrane structures inside the rough endoplasmic reticulum characterized the unique fatal isolate examined.

Morphological aspects of the myocarditis and myositis in Calomys callosus experimentally infected with Trypanosoma cruzi: fibrogenesis and spontaneous regression of fibrosis

Calomys callosus a wild rodent, is a natural host of Trypanosoma cruzi. Twelve C. callosus were infected with 10(5) trypomastigotes of the F strain (a myotropic strain) of T. cruzi. Parasitemia decreased on the 21 st day becoming negative around the 40th day of infection. All animals survived but had positive parasitological tests, until the end of the experiment. The infected animals developed severe inflammation in the myocardium and skeletal muscle. This process was pronounced from the 26 th to the 30th day and gradually subsided from the 50 th day becoming absent or residual on the 64 th day after infection. Collagen was identified by the picro Sirius red method. Fibrogenesis developed early, but regression of fibrosis occurred between the 50th and 64th day. Ultrastructural study disclosed a predominance of macrophages and fibroblasts in the inflammatory infiltrates, with small numbers of lymphocytes. Macrophages had active phagocytosis and showed points of contact with altered muscle cells. Different degrees of matrix expansion were present, with granular and fibrilar deposits and collagen bundles. These alterations subsided by the 64th days. Macrophages seem to be the main immune effector cell in the C. callosus model of infection with T. cruzi. The mechanisms involved in the rapid fibrogenesis and its regression deserve further investigation.

Ecoepidemiological aspects of american cutaneous leishmaniasis in the state of São Paulo, Brazil

The aim of this study is to review some of the ecoepidemiological aspects of american cutaneous leishmaniasis (ACL) in the state of São Paulo, Brazil. During the first half of this century ACL occured in São Paulo, predominantly on the bank of the Tietê river, where there were railroad constructions and there was inevitable contact between and forested areas. Man's activities resulted in a drastic reduction of the forested regions of the state and molded the present landscape found in São Paulo, which brought a gradual change in the epidemiology of ACL during this century. Currently ACL can be considered as an endemic disease. Nowadays, ACL is found in different regions of São Paulo state, and is no longer limited to the bank of the Tietê river. The disease occurs in all age groups and sexes. Lack of knowledge about wild reservoir hosts of Leishmania (V.) braziliensis has simulated speculation about the possible role played by domestic animals (dogs and equines). Man's activities also favoured Lutzomyia intermedia a sandfly species which can clearly thrive in changed environments L. (V.) braziliensis continues to be transmitted, even after decades of forest destruction in São Paulo.

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.

Personal experience with diagnostic and therapeutic aspects of human Leishmania (Viannia) braziliensis in Três Braços

Diagnostic and therapeutic aspects of human infection with Leishmania (Viannia) braziliensis found in the littoral forest of the state of Bahia are reviewed. There is pressing need for alternative cheap oral drug therapy.

Aspects of immunity for the AMA-1 family of molecules in humans and non-human primates malarias

The apical membrane antigen (AMA-1) family of malaria merozoite proteins is characterised by a high degree of inter-species conservation. Evidence that the protein (PK66/AMA-1) from the simian parasite Plasmodium knowlesi was protective in rhesus monkeys suggested that the 83kDa P. falciparum equivalent (PF83/AMA-1) should be investigated for protective effects in humans. Here we briefly review pertinent comparative data, and describe the use of an eukaryotic full length recombinant PF83/AMA-1 molecule to develop a sensitive ELISA for the determination of serological responses in endemic populations. The assay has revealed surprisingly high levels of humoral response to this quantitatively minor antigen. We also show that PK66/AMA-1 inhibitory mAb's are active against merozoites subsequent to release from schizont-infected red cells, further implicating AMA-1 molecules in red cell invasion.

Molecular aspects of Schistosoma mansoni female maturation

Incubation of total protein extracts of Schistosoma mansoni with 3H 17-beta-estradiol and 20-hydroxyecdysone, revealed steroid binding proteins in both, male and female worms. The interaction of nuclear proteins with restriction fragments of the gender and stage-specific gene F-10 was investigated using the "Band-Shift" technique. Distinct male and female nuclear proteins bound to the fragments of this gene. Among the nuclear proteins, only those rich in cysteine residues bound to DNA. In vitro incubation of live worms with the estrogen antagonist Tamoxifen, altered the pattern of the DNA binding proteins, producing in females, a band profile similar to that obtained with male worm protein extracts. When Tamoxifen was injected into schistosome infected mice, the eggs produced by females presented an abnormal morphology, compatible with non-viable eggs. These results suggest that the regulation of transcription of the F-10 gene might involve steroid receptors.

Ultrastructural aspects of spermatogonesis in Metamicrocotyla macracantha (Alexander, 1954) Koratha, 1955 (Monogenea; Microcotylidae)

Ultrastructural aspects of spermatogenesis, spermiogenesis and of the mature spermatozoon of a microcotylid monogenean Metamicrocotyla macracantha parasite from Mugil liza, are described. The irregularly-shaped spermatogonia divides by successive mitoses, forming the primary spermatocytes, identified by the presence of synaptonemal complexes in their nuclei. The spermatids formed by meiotic cell divisions of the secondary spermatocytes, differentiate into a mature spermatozoon. Cross sections of the head and the middle region of mature spermatozoa show the nucleus with strong condensed chromatin, the mitochondria with short cristae, peripheral microtubules and two axonemes with a 9+1 pattern, confirming the characteristics of this genus.

Thermal effect on the life-cycle parameters of the medically important freshwater snail species Lymnaea (Radix) luteola (Lamarck)

The snails Lymnaea (Radix) luteola exhibited marked variations in growth, longevity, and attaining sexual maturity at different temperatures and diets. At 10°C, irrespective of foods, pH and salinity of water, the snails had minimum life span, maximum death rate and lowest growth rate. At 15°C, the growth rate was comparatively higher and the snails survived for a few more days. But at these temperatures they failed to attain sexual maturity. Snails exposed to pH 5 and 9 at 20°, 25°, 30°, 35°C and room temperatures (19.6°-29.6°C); to 0.5, 1.5 and 2.5 NaCl ‰ at 20° and 35ºC; to 2.5 NaCl ‰ at 25°C and room temperatures failed to attain sexual maturity. The snails exposed to pH 7 and different salinity grades at 20°, 25°, 30°, 35°C and room temperatures became sexually mature between 25-93 days depending upon the type of foods used in the culture.

Morphological Aspects of the Larval Instars of Chrysomya albiceps (Diptera, Calliphoridae) Reared in the Laboratory

In order to study the morphology of young Chrysomya albiceps forms, newly hatched larvae were collected at 2 hr intervals, during the first 56 hr; after this time the collection was made at 12 hr intervals. For identification and drawing, larvae were placed between a slide and a coverslip. The cephalopharyngeal skeletons along with the first and last segments were cut off for observation of their structures and spiracles. The larvae present microspines, which are distributed randomly throughout the 12 segments of the body surface; the cephalopharyngeal skeleton varies in shape and extent of sclerotization according to larval instar; the second and third instars have relatively long processes (tubercles) on the dorsal, lateral and ventral surfaces, with microspine circles on the terminal portion

Reproductive Aspects of Haemaphysalis leporis-palustris

The adult stage of Haemaphysalis leporis-palustris was studied. Two infestations consisted of male and female ticks on two rabbits (Oryctolagus cuniculus). Other two infestations consisted of only female ticks on two O. cuniculus. Females fed without males showed differences in some biological parameters when compared to females fed with males. Parthenogenesis is reported for the first time by one H. leporis-palustris female