Jatobal virus antigenic characterization by ELISA and neutralization test using EIA as indicator, on tissue culture

A virus antigenic characterization methodology using an indirect method of antibody detection ELISA with virus-infected cultured cells as antigen and a micro virus neutralisation test using EIA (NT-EIA) as an aid to reading were used for antigenic characterization of Jatobal (BeAn 423380). Jatobal virus was characterized as a Bunyaviridae, Bunyavirus genus, Simbu serogroup virus. ELISA using infected cultured cells as antigen is a sensitive and reliable method for identification of viruses and has many advantages over conventional antibody capture ELISA's and other tests: it eliminates solid phase coating with virus and laborious antigen preparation; it permits screening of large numbers of virus antisera faster and more easily than by CF, HAI, or plaque reduction NT. ELISA and NT using EIA as an aid to reading can be applicable to viruses which do not produce cytopathogenic effect. Both techniques are applicable to identification of viruses which grow in mosquito cells.

On Pomacea sordida (Swainson, 1823) (Prosobranchia, Ampullariidae)

A description of Pomacea sordida (Swainson, 1823) collected in Caxias and Nova Iguaçu, state of Rio de Janeiro, is presented. The shell is globose, heavy, whith greenish or horn-colored periostracum and dark spinal bands; apex subelevated, 4-5 moderately shoudered whorls, increasing rather rapidly and separated by deep suture. Aperture large, moderately round, yellowish or violaceous; lip thick and sometimes dark brown; umbilicus large and deep; operculum corneous and heavy, entirely closing the aperture. Ratios: shell width/shell length = 0.81-0.91 (mean 0.86); aperture length/shell length = 0.66-0.75 (mean 0.70). Testis, spermiduct and penis pouch as in Pomacea lineata (Spix, 1827). Seminal vesicle whitish and bean-shaped. Prostate cylindric and narrow, cream in coloar as the testis. Penis whiplike whith a closed circular spermiduct. Penial sheath elongated and tapered, with its distal tip turned to the right; outer basal gland situated on the left; inner median gland rounded; apical gland elongated and wrinkled. Ovary composed of branched whitish tubules lying superficially on the digestive gland; oviduct and seminal receptacle as in P. lineata; albumen gland yellowish - orange. Vestigial male copulatory apparatus (penis and its sheath) present in all females examined.

Harmonization of research and control in schistosomiasis

I have been employed by several different organizations during over 30 years working on schistosomiasis, the majority spent in endemic areas of Caribean, South America, Africa and the Western Pacific. Much of the work is best classified as applied research but sometimes it strayed to the extremes of either public health control programmes or pure research. Over this period, there have been several significant research developments that have altered our whole approach to control. Ideally, research and control should complement each other but, in reality, they sometimes have conflicting objectives. Public health workers understandably wish to provide immediate, shot-term protection to the communities in their care, but research workers may, within ethical limits, reasonably want to observe untreated communities for extended periods in order to understand the underluing process of transmission, disease pathogenesis and immunity to help develop more effective control measures. An example of this situation has occured recently in Senegal where water development projects seem to have favoured the introduction and spreed of Schistosoma mansoni in the Senegal River Basin. I have been asked to be the scientific consultant to the newly formed ESPOIR programme, linking European research organizations and the Senegal Ministry of Health, to reconcile the conflictiong aims of public health workers, wishing to use whatever funds can be obtained for an immediate chemotherapy to try to eliminate the focus, at present confined to the vicinity of a relatively small, commercially run sugar irrigation scheme; and research workers who see a rare chance to study the development of immune mechanisms in a adults in a community not previously exposed to the infection. This information could prove invaluable in understanding the development of immunity and the pathogenesis of disease, leading eventually to the development of vaccines to revolutionise the future approach to schistosomiasis...

Factors conditioning the habitat and the density of Biomphalaria tenagophila (Orbigny, 1835) in an isolated schistosomiasis focus in Rio de Janeiro city

The present work was carried out in a watercress garden in Alto da Boa Vista, in the city of Rio de Janeiro, Brazil. The investigation was carried out in two phases. The first one (1985-86) involved the sampling of Biomphalaria tenegophila in two areas to determine its relative populational densities. The results showed that the populations presented similar densities and dynamics. The second phase (1988-89) involved the study of the influence of some environmental factors on the establishment of B. tenagophila in watercress garden. Two factors were identified as responsible for the establishment of B. tenagophila in the garden: (1) the quality of the water entering the irrigation system, to which domestic sewage is added, and (2) alterations in the nature of the substrate, due to inadequate fertilization techniques, which employ organic matter from adjacent pigsties. Aquatic plants and hydrological parameters of the irrigation system were subsidiary factors to the establishment of B. tenagophila in the garden.

Molluscicidal action of the latex of Euphorbia splendens var. hislopii N.E.B. ("Christ's Crown") (Euphorbiaceae) against Lymnaea columella (Say, 1817) (Pulmonata: Lymnaeidae), intermediate host of Fasciola hepatica Linnaeus, 1758 (Trematode: Fasciolidae): 1- test in laboratory

The latex action of Euphorbia splendens var. hislopii (Christ's Crown) against snails Lymnaea columella, intermediate host of Fasciola hepatica, derived from irrigation ditches of the Station of Pisciculture at Universidade Federal Rural do Rio de Janeiro, was studied in the laboratory. Lab bioassays, using aqueous solutions of the latex, varying between 0.1 and 10 mg/l, have proven molluscicidal activity of the product collected on the same day the tests were performed, during the four seasons of the year, finding the following lethal concentrations (LC90): 1.51 mg/l in the spring; 0.55 mg/l in the summer; 0.74 mg/l in the fall and 0.93 mg/l in winter, after 24 h exposure of the snails, showing significant differences among the seasons of the year (ANOVA test, F = 11.01, G.L.= 3/33, p < 0.05), as well as among the concentrations (ANOVA test, F = 27.38, G.L.= 11/33, p < 0.05). In the summer, mortality reached 100% from concentration at 0.6 mg/l, the same during fall and in winter as of 1 mg/l, while in spring it only reached 100% mortality as of 2 mg/l. Mortality in the controls was low, reaching 5% in the summer and winter and 10% in the fall and spring. None of the samples died. During the assay, with an aqueous solution of the latex at a concentration of 5 mg/l, in order to check the time of duration of the product effect, in the laboratory, it was observed that the molluscicidal activity remained stable up to the 15th day after the beginning of the test with 100% mortality of L. columella, gradually losing its effect until the 23rd day, when we no longer observed animal mortality. In the control group, there was a random daily variation in mortality rate ranging 0-50% after 48 h of observation for 30 days.

Activity of Euphorbia splendens var. hislopii N.E.B. (Euphorbiaceae) latex against Lymnaea columella (Say, 1817) (Pulmonata: Lymnaeidae), intermediate host of Fasciola hepatica, Linnaeus, 1758 (Trematoda: Fasciolidae). 2: limited field-testing

The molluscicidal evaluation of Euphorbia splendens var. hislopii (Crown of thorns) against Lymnaea columella snails, intermediate host of Fasciola hepatica, in irrigation ditches of the Pisciculture Station at Universidade Federal Rural do Rio de Janeiro, was studied under limited field conditions. An aqueous solution of the latex at 5 mg/l was tested in two irrigation ditches (experimental and control ditches), after initial sampling of the snail population present. Twenty-four hours after application of the product, it was verified that 97.4% of free L. columella snails and 100% of snails of the same species captive in cages and used as sentinels at three points equidistant from the application site in the experimental ditch, died. For Biomphalaria tenagophila and Melanoides tuberculata snails, present in the experimental ditch, the mortality was 100%, for the species Pomacea spp. the mortality was 40%. No mortality was verified in the free mollusks, or in the sentinels in the ditch used as control. E. splendens var. hislopii latex is thus an efficient natural molluscicide, which may be used as an alternative control agent against L. columella.

The origin and dispersion of human parasitic diseases in the Old World (Africa, Europe and Madagascar)

The ancestors of present-day man (Homo sapiens sapiens) appeared in East Africa some three and a half million years ago (Australopithecs), and then migrated to Europe, Asia, and later to the Americas, thus beginning the differentiation process. The passage from nomadic to sedentary life took place in the Middle East in around 8000 BC. Wars, spontaneous migrations and forced migrations (slave trade) led to enormous mixtures of populations in Europe and Africa and favoured the spread of numerous parasitic diseases with specific strains according to geographic area. The three human plasmodia (Plasmodium falciparum, P. vivax, and P. malariae) were imported from Africa into the Mediterranean region with the first human migrations, but it was the Neolithic revolution (sedentarisation, irrigation, population increase) which brought about actual foci for malaria. The reservoir for Leishmania infantum and L. donovani - the dog - has been domesticated for thousands of years. Wild rodents as reservoirs of L. major have also long been in contact with man and probably were imported from tropical Africa across the Sahara. L. tropica, by contrast, followed the migrations of man, its only reservoir. L. infantum and L. donovani spread with man and his dogs from West Africa. Likewise, for thousands of years, the dog has played an important role in the spread and the endemic character of hydatidosis through sheep (in Europe and North Africa) and dromadary (in the Sahara and North Africa). Schistosoma haematobium and S. mansoni have existed since prehistoric times in populations living in or passing through the Sahara. These populations then transported them to countries of Northern Africa where the specific, intermediary hosts were already present. Madagascar was inhabited by populations of Indonesian origin who imported lymphatic filariosis across the Indian Ocean (possibly of African origin since the Indonesian sailors had spent time on the African coast before reaching Madagascar). Migrants coming from Africa and Arabia brought with them the two African forms of bilharziosis: S. haematobium and S. mansoni.

Distribution and Schistosoma mansoni infection of Biomphalaria glabrata in different habitats in a rural area in the Jequitinhonha Valley, Minas Gerais, Brazil: environmental and epidemiological aspects

This paper examines the distribution and infection of Biomphalaria glabrata with Schistosoma mansoni in all aquatic snail habitats in a rural area in the state of Minas Gerais, Brazil, in relation to physico/biotic and behavioral factors. Snail and environmental surveys were carried out semi-annually between July 2001 and November 2002 at 106 sites. Collected snails were examined in the laboratory for infection. B. glabrata densities were highest in overflow ponds, irrigation ponds, springs, canals and wells, and lowest in fishponds and water tanks. Snail densities were higher during the hot, rainy season except for streams and canals and were statistically associated with the presence of fish, pollution, and vegetation density. Tilapia fish and an unidentified Diptera larva were found to be predators of B. glabrata but ducks were not. Twenty-four of the 25 infected snails were collected in 2001(1.4% infection rate) and only one in 2002, after mass chemotherapy. The occurrence of B. glabrata in all 11 snail habitats both at and away from water contact sites studied indicates widespread risk of human infection in the study area. In spite of the strong association between B. glabrata and tilapia in fishponds we do not recommend its use in schistosomiasis control for ecological reasons and its relative inefficiency in streams and dams.

Biomphalaria spp. (Preston, 1910) snails in the municipality of Juiz de Fora, Zona da Mata Mineira mesoregion, ate of Minas Gerais, Brazil

This study focuses on the geographic distribution of the snail of the genus Biomphalaria and evaluates its infectivity by Schistosoma mansoni in 5264 specimens collected in the municipality of Juiz de Fora, Minas Gerais, Brazil. Of the 31 locations studied, 6 were reservoirs, 11 rudimentary holding ponds, 7 irrigation ditches, 5 lakes, 1 ornamental pond, and 1 waterfall. Intermediate hosts were found only in the rudimentary ponds and ditches, which were 100% positive. Using morphological and molecular analysis techniques, B. tenagophila, B. peregrina, and B. straminea were identified. This is the first report of B. stramínea in the municipality, and evaluation of its infective potential revealed susceptibility of 25.4%. Although we did not find specimens of Biomphalaria infected by S. mansoni, the data obtained indicate the presence of intermediate hosts, especially in the irrigation ditches in Juiz de Fora, and their proximity to contaminated areas.

New record and larval habitats of Culex eduardoi (Diptera: Culicidae) in an irrigated area of Patagonia, Chubut Province, Argentina

The object of the present work was to identify the larval habitats of Culex eduardoi and to determine the microenvironmental conditions related to their presence in different artificial freshwater environments (temporary, semi-permanent, irrigation ditches, and drainage ditches) in tillable areas of Chubut Province, Argentina. This report represents the first record of Cx. eduardoi from this Province and extends its range to latitude 45°S. Immature stages of Cx. eduardoi were found in 8 out of 109 (7.3 %) freshwater habitats and were significantly more prevalent in semi-permanent water bodies. Positive sites had significantly larger surface areas and more vegetation cover than negative sites.

Distribution of Lymnaeidae (Mollusca: Pulmonata), intermediate snail hosts of Fasciola hepatica in Venezuela

An extensive malacological survey was carried out between 2005-2009 in order to clarify the exact number of lymnaeid species which may be intermediate hosts of Fasciola hepatica in Venezuela. Four species were discovered during this survey, including two local species: Lymnaea cubensis and Lymnaea cousini and two exotic species: Lymnaea truncatula and Lymnaea columella. The most common local species was L. cubensis which was found at 16 out of the 298 sampling sites. This species has a large distribution area throughout the Northern part of Venezuela and was encountered from sea level to an altitude of 1,802 m in state of Trujillo. The second local species L. cousini was collected at only two sites of the Andean Region at altitudes of 3,550 m and 4,040 m, respectively. The European L. truncatula was found at 24 sites all located in the states of Mérida and Táchira at an altitude varying between 1,540-4,000 m. The respective distribution areas of L. cubensis and L. truncatula do not appear to overlap, but more detailed malacological surveys are needed. The fourth lymnaeid species, L. columella was collected in a canal from Mérida at an altitude of 1,929 m and in an irrigation canal from the state of Guárico, at an altitude of 63 m. The role of these four lymnaeid species in the transmission of fascioliasis in Venezuela is discussed.