Host-parasite relationship between Biomphalaria amazonica (Paraense, 1966) and Schistosoma mansoni (Sambon, 1907) / Relação parasito-hospedeiro entre Biomphalaria amazonica e Schistosoma mansoni

Abstract Biomphalaria amazonica is a planorbid species considered a potential host of Schistosoma mansoni. It is widely distributed in the Neotropical zone, particularly in the North and Centre-West of Brazil and in the North of Bolivia. The aim of the present study was to determine the host-parasite relationship between B. amazonica and S. mansoni (BH and SJ strains). Specimens of B. amazonica and their snail-conditioned water were examined in terms of their ability to attract miracidia. The infectivity of the mollusks was determined by exposing them to 20 miracidia of both strains. Sporocyst development and amebocyte reactions were studied after each mollusk specimen was exposed to 100 miracidia. Although no cercariae were eliminated, specimens of B. amazonica proved capable of attracting 77% of the miracidia they were exposed to. Viable sporocysts with no amebocyte reaction were found 96 hours after the exposure to miracidia. These results indicate the susceptibility of B. amazonica to the BH and SJ strains of S. mansoni, and therefore demonstrate the importance of this planorbid species as a potential vector of the trematode in the areas where it occurs.

Resumo Biomphalaria amazonica é uma espécie de planorbídeo considerada vetora potencial do Schistosoma mansoni. É amplamente distribuída na zona neotropical, especialmente no Norte e Centro-Oeste do Brasil e Norte da Bolívia. O presente trabalho teve por objetivo estudar a relação parasito-hospedeiro entre B. amazonica e S. mansoni (linhagens BH e SJ). Espécimes de B. amazonica e sua água de condicionamento foram examinados em relação à sua capacidade de atração miraxonal. A infectividade dos moluscos foi testada expondo-os a 20 miracídios de ambas as linhagens. A viabilidade dos esporocistos e o desenvolvimento de reações amebocitárias foram estudados após cada molusco ser exposto a 100 miracídios. Apesar de não eliminarem cercárias, B. amazonica provou ser capaz de atrair 77% dos miracídios a que foram expostos. Esporocistos viáveis sem reação amebócitaria foram encontrados 96 horas após a exposição aos miracídios. Esses resultados indicam a suscetibilidade de B. amazonica às linhagens BH e SJ de S. mansoni e, portanto, demonstram a importância desta espécie de planorbídeo como um vetor potencial do trematodeo na área onde ele ocorre.

Host-parasite relationship between Biomphalaria amazonica (Paraense, 1966) and Schistosoma mansoni (Sambon, 1907).

Biomphalaria amazonica is a planorbid species considered a potential host of Schistosoma mansoni. It is widely distributed in the Neotropical zone, particularly in the North and Centre-West of Brazil and in the North of Bolivia. The aim of the present study was to determine the host-parasite relationship between B. amazonica and S. mansoni (BH and SJ strains). Specimens of B. amazonica and their snail-conditioned water were examined in terms of their ability to attract miracidia. The infectivity of the mollusks was determined by exposing them to 20 miracidia of both strains. Sporocyst development and amebocyte reactions were studied after each mollusk specimen was exposed to 100 miracidia. Although no cercariae were eliminated, specimens of B. amazonica proved capable of attracting 77% of the miracidia they were exposed to. Viable sporocysts with no amebocyte reaction were found 96 hours after the exposure to miracidia. These results indicate the susceptibility of B. amazonica to the BH and SJ strains of S. mansoni, and therefore demonstrate the importance of this planorbid species as a potential vector of the trematode in the areas where it occurs.

Egg Developmental Time and Survival of Chrysomya megacephala and Chrysomya putoria (Diptera: Calliphoridae) Under Different Temperatures.

Chrysomya megacephala (F.) and Chrysomya putoria (Wiedemann) (Diptera: Calliphoridae) are considered of forensic, medical, and veterinary importance in Brazil because of their necrophagous and synanthropic behaviour. The development of flies can be influenced by temperature, and species from the same genus usually have different responses to external variables. The egg development of blow fly can be a useful complementary technique to estimate the minimum postmortem interval. Thus, this study aimed to compare the egg developmental time and survival of C. megacephala and C. putoria at different temperatures to determine the optimal temperature for egg development and the linear regression for developmental time and temperature, thereby determining the minimum threshold (t) and thermal summation constant (K) for each species. Adults of both species were collected in the region of Campinas city, São Paulo state, Brazil. Eggs were incubated at eight constant temperatures between 05 ± 1°C and 35 ± 1°C and the egg developmental time and survival were evaluated. There was no egg survival at 5 and 10°C. The K for C. megacephala and C. putoria were 179.41 HD and 189.94 HD, respectively. The regression slopes and t (10°C) were similar for both species. The optimal temperature for egg survival was between 25 and 35°C, for C. megacephala and 20 and 30°C, for C. putoria. The present data were similar to most data available in the literature, but differences in the same species are a possibility.

Seasonal composition and temporal succession of necrophagous and predator beetles on pig carrion in central Argentina.

Insects are the most important components of the terrestrial fauna associated with carrion because they recycle organic matter back into the ecosystem. They can be classified into four ecological categories comprising: necrophages; parasites and predators of necrophagous species; omnivores, and incidentals. To determine the composition and temporal succession of necrophagous and predator beetles on pig carrion, four experiments, one in each season, were carried out during 2004 in a rural area of Cordoba, central Argentina. Two pigs (Sus scrofa L.), weighing approximately 8 kg each, were used in each of the four experiments. The animals were killed by a sharp blow to the head and immediately placed in an appropriate trap. One pig was placed in the shade and the other in direct sunlight. Beetle fauna were collected daily during the first 4 weeks and thereafter every 2 or 3 days. Five stages of decomposition were observed and a total of 1586 adults and 4309 immatures of Coleoptera belonging to the Staphylinidae, Nitidulidae, Cleridae, Dermestidae, Histeridae, Anthicidae and Trogidae families were collected during the four experiments. The necrophagous community was represented by Dermestes maculates (De Geer), nitidulid species and members of the Trox genus. Staphylinidae, Cleridae and Histeridae species were considered to be the main predators of the necrophagous species.

Effect of nandrolone decanoate on the development of three species of Chrysomya (Diptera:Calliphoridae), flies of forensic importance in Brazil.

Necrophagous insects are valuable tools for postmortem interval (PMI) estimation or for determining the cause of death. Due to the increase in deaths related to drug abuse, it is crucial to know how these substances affect the development of flies that feed on corpses, to avoid errors in the PMI estimates. This study evaluated the effect of nandrolone decanoate, an anabolic androgenic steroid, on the development ofimmatures of Chrysomya megacephala (F.), Chrysomya putoria (Wiedemann), and Chrysomya albiceps (Wiedemann) (Diptera:Calliphoridae) when added to an artificial rearing diet. Four experimental groups were delineated: three of them were given diets containing 4.5, 22.5, or 45 mg/kg nandrolone decanoate; and a drug-free control group. Weights were recorded at 12-h intervals from larval eclosion to pupation. No statistically significant differences were observed in mean larval weights, emergence interval, or emergence rates for all groups. However, differences in the three species were observed during the larval development. Initially, C. putoria reared in the highest concentration of decanoate showed greater weight gain. However, at older ages, immatures reached lower mean weights than the control group. For C. albiceps, the highest concentration of decanoate contributed to an effective lack of weight gain during almost the entire course of larval development. Therefore, the influence of any drug on development should always be considered.

Attraction of Schistosoma mansoni Sambon, 1907 miracidia to Biomphalaria glabrata (Say, 1818) in the presence of Angiostrongylus costaricensis Morera and Céspedes, 1971 infection.

The attraction exerted by Biomphalaria glabrata infected with Angiostrongylus costaricensis on Schistosoma mansoni miracidia of the BH strain was tested, using a glass apparatus composed by two circular chambers connected to a channel. One mollusk or a sample of a snail conditioning water (SCW) was placed in one of the chambers, randomly selected, and the remaining of the apparatus was filled with chlorine-free water. Ten miracidia were placed in the centre of the channel and their behaviour was observed for 15 minutes. Ten replicates were made for each treatment (snail or SCW), using different specimens of mollusks or different samples of SCW. Mollusks infected with A. costaricensis attracted significantly less S. mansoni miracidia than non-infected B. glabrata. In addition, miracidia were also significantly more attracted to SCW from mollusks infected with A. costaricensis.

Behavior of Angiostrongylus costaricensis in planorbids.

Some terrestrial mollusks are natural hosts of Angiostrongylus costaricensis. In the laboratory, this nematode can be maintained in certain planorbids, which are aquatic mollusks and intermediate hosts of Schistosoma mansoni. Mollusks can be infected with Angiostrongylus costaricensis by ingestion of or active penetration by the first-stage larvae. In this work we assessed the ability of Biomphalaria glabrata to attract first-stage larvae of A. costaricensis. Movement of the nematode larvae towards the mollusks was observed after 15 min, 30 min and 1 h. B. glabrata did not attract the first-stage larvae of A. costaricensis in any of the three intervals. The susceptibility of two populations of Biomphalaria tenagophila to infection by A. costaricensis was also determined. One population was genetically selected for the susceptibility to S. mansoni while the other was not. Third-stage larvae were recovered from the snails 30 days after exposure of the two populations to 120 first-stage larvae. All the mollusks were infected. However, a significantly higher number of third-stage larvae were recovered in mollusks not genetically selected.

Behavior of Angiostrongylus costaricensis in planorbids

Alguns moluscos terrestres são hospedeiros naturais do Angiostrongylus costaricensis. No laboratório, esse nematódeo pode ser mantido em planorbídeos, que são moluscos aquáticos e hospedeiros intermediários do Schistosoma mansoni. Os moluscos podem ser infectados com A. costaricensis por ingestão ou por penetração ativa de larvas de primeiro estágio. Neste trabalho, testamos a habilidade de Biomphalaria glabrata em atrair larvas de primeiro estágio de A. costaricensis. A movimentação das larvas do nematódeo em direção aos moluscos foi observada após 15 minutos, 30 minutos e 1 hora. B. glabrata não atraiu as larvas de primeiro estágio de A. costaricensis nos três intervalos de tempo. Verificamos também a suscetibilidade de duas populações de Biomphalaria tenagophila à infecção por A. costaricensis. Uma população era selecionada geneticamente para a susceptibilidade ao S. mansoni, enquanto a outra não o era. Larvas de terceiro estágio foram recuperadas dos moluscos 30 dias após a exposição das duas populações a 120 larvas de primeiro estágio. Todos os moluscos estavam infectados. Entretanto, um número significativamente maior de larvas de terceiro estágio foi recuperado em moluscos não geneticamente selecionados.

Muscoid dipterous collected from cattle dung pats in pastures in Itumbiara, Goiás, Brazil

A coleta de Diptera em fezes bovinas depositadas nas pastagens foi conduzida de janeiro a agosto de 2001 em Itumbiara, Goiás. As fezes foram expostas nas pastagens por 24, 48, 72, 96, 120, 144, 168, 192, 216 e 240 horas e posteriormente levadas para laboratório para extraçäo e separaçäo dos dípteros. Um total de 100 fezes bovinas foram expostas nas pastagens, das quais 3099 dípteros muscóides foram coletados. As espécies mais abundantes foram: Palaeosepsis spp. e Sarcophagula occidua. A maioria dos exemplares foi coletada em fezes bovinas expostas nos períodos de 72 e 144 horas no campo

Determination of drug levels and the effect of diazepam on the growth of necrophagous flies of forensic importance in southeastern Brazil.

Larvae of Chrysomya albiceps (Wiedemann) and Chrysomya putoria (Wiedemann) (Diptera: Calliphoridae) were reared on tissues from rabbits administered twice the lethal dosage of diazepam in order to study the effects of this drug on the development of these two species. The rabbits were given 50mg of diazepam via ear vein infusion. From 18 to 54h, larvae feeding on tissues containing the drug developed more rapidly than larvae from the control colony for both fly species. The time required for pupariation and adult emergence was significantly greater for colony fed on tissues from diazepam dosed rabbits than for the control ones. These differences are significant for they are large enough to alter the estimate of postmortem interval based on fly development. The presence of diazepam could be detected through gas chromatography-mass spectrometer (GC-MS) in all rabbit samples and in almost all diptera samples in this experiment.

Seasonality of insect succession and pig carcass decomposition in a natural forest area in southeastern Brazil.

In this study, successional patterns, relative abundance of larvae and adults of sarcosaprophagous insects, carcass decay, diversity and seasonality of species, and their potential as forensic indicators were studied. Four experiments were carried out in each season in a natural area of southeastern Brazil. Two pigs (Sus scrofa L.) were used in each experiment and were exposed to sunlight and shade, respectively. The Calliphoridae outnumbered the Sarcophagidae in specimens collected and reared from the carcasses. More insects were collected from carcasses exposed to the sun, while a larger number of specimens were reared from those in the shade. Temperature and rainfall influenced the stages of carcass decay and insect activity and abundance. Chrysomya albiceps was the most abundant species in all four experiments. The carcasses were used as a protein source and substratum for oviposition. The dark putrefaction and fermentation stages yielded more flies than the other stages. These results show that flies are important in carcass decay and are, therefore, also of forensic importance. Seven species can be considered valuable forensic indicators in Southeastern Brazil. However, only three species were useful as forensic indicators in wooded areas: P. intermutans, H. segmentaria, and H. semidiaphana.

First report of Paraganaspis egeria Díaz & Gallardo (Hymenoptera: Eucoilidae) parasiting horn fly, Haematobia irritans L. (Diptera: Muscidae) in the Southeastern Brazil

Este trabalho relata a primeira ocorrência do parasitóide Paraganapis egeria Diaz & Gallardo (Hymenoptera: Eucoilidae) parasitando pupas de Haematobia irritans L. (Diptera: Muscidae) na regiäo Neotropical. As fezes bovinas foram coletadas nas pastagens da Fazenda Canchim da Embrapa de Säo Carlos-SP, de abril de 1993 a abril de 1994. As pupas foram separadas das fezes bovinas por flutuaçäo em baldes com água. As recolhidas foram acondicionadas individualmente em cápsulas de gelatina até a emergência dos dípteros ou dos seus parasitóides. Foram obtidas 718 pupas de H. irritans, das quais duas emergiram parasitóides. Constatou-se parasitismo de 0,26 por cento

Dípteros muscóides associados com carcaça de suíno e seus parasitóides em área de pastagem e de mata em Goiás / Muscoids dipterous insects associated with pig carcass and their parasitoids collected in areas of pasture and of wood in Goiás, Brazil

Muscoid dipterous insects associated with pig carcass and their parasitoids collected in pasture and wood were collected from savanna (cerrado) at Goiás, Brazil. The species collected more often were: Chrysomya albiceps (89.5 per cent ), Ophyra sp. (6.9 per cent) (flies) and Pachycrepoideus vindemiae (33.3 per cent) and Spalangia endius (38.8 per cent) (parasitoids). The parasitism rate was 0.4 per cent

Dípteros muscóides associados com fezes bovinas e seus parasitóides em Goiás / Muscoid dipterous insects associated with cattle feces and their parasitoids in Goiás State, Brazil

A total number of 8779 pupae of Diptera were collected in stables in the municipal district of Itumbiara, GO, Brazil, from June to December 1999. The principal fly and parasitoid species found were Musca domestica L. (38.4 per cent), Sarcophagula occidua Fabricius (51.5 per cent) (flies), Pachycrepoideus vindemiae (Rondani) (28.0 per cent) and Paraganaspis egeria Diaz & Gallardo (29.3 per cent)

Espécies de Spalangia (Hymenoptera: Pteromalidae Spalanginae) em fezes bovinas como parasitóides pupais de dípteros muscóides em Goiás / Species of Spalangia (Hymenoptera: Pteromalidae: Spalangiane) as parasitoid pupa of muscoid dipterous insects in cattle feces in Goiás State, Brazil

Species of parasitoids of dung-breeding Diptera were collected at a range pasture in Itumbiara, GO, Brazil. The samples of bovine dung, approximately seven and eight day-old, were collected and carried to the laboratory and the pupae were extracted by water flotation. The pupae were individually placed in transparent gelatin capsules until the emergence of the adult flies or their parasitoids. Spalangia drosophilae (40.8 per cent) Ashmead and Spalangia nigroaenea (35.6 per cent) were the predominant species that parasitized pupae of dipterous muscoids. The rate of parasitism was 3.8 per cent

Trichobius joblingi, Aspidoptera falcata, and Megistopoda proxima (Diptera : Streblidae) parasitic on Carollia perspicallata and Sturnia lillium (Chiroptera : Phyllostomidae) in southeastern Brazil: sex ratios, seasonality, host site preference, and effect of parasitism on the host.

This note examines the effect of parasitism on host size, the preference of the parasite for a specific host body area, and the seasonal abundance for the 3 most abundant bat flies (i.e., Trichobius joblingi Wenzel, a parasite of the bat Carollia perspicillata [Linnaeus], and Aspidoptera falcata Wenzel and Megistopoda proxima [Séguy], parasites on Sturnira lilium [Geoffroy]). Trichobius joblingi and A. falcata are moderately dorsoventrally flattened and were collected on the wing membranes of their hosts, and M. proxima is moderately laterally compressed, has long, thin hind legs, and was collected in the body fur of the host. These 3 parasites also showed distinct seasonal patterns. There was a significant negative correlation between the simultaneous occurrence of A. falcata and M. proxima on the host. Parasitism by M. proxima was correlated with a significant weight loss in male S. lilium, which may reflect the large size, high activity, and constant feeding of this parasite, thereby causing a significant negative effect on the host. Sex ratios favoring male flies could be explained by the tendency of female flies to leave the host immediately before the bat leaves the shelter in search for food or immediately after bats are collected but could also be a consequence of higher mortality among females, especially gravid ones. Finally, collecting may have influenced the skewed sex ratio because male flies, being more active, were more evident to the collector.

A checklist of arthropods associated with pig carrion and human corpses in southeastern brazil.

Necrophagous insects, mainly Diptera and Coleoptera, are attracted to specific stages of carcass decomposition, in a process of faunistic succession. They are very important in estimating the postmortem interval, the time interval between the death and the discovery of the body. In studies done with pig carcasses exposed to natural conditions in an urban forest (Santa Genebra Reservation), located in Campinas, State of São Paulo, southeastern Brazil, 4 out of 36 families of insects collected - Calliphoridae, Sarcophagidae, Muscidae (Diptera) and Dermestidae (Coleoptera) - were considered of forensic importance, because several species were collected in large numbers both visiting and breeding in pig carcasses. Several species were also observed and collected on human corpses at the Institute of Legal Medicine. The species belonged to 17 different families, 6 being of forensic importance because they were reared from human corpses or pig carcasses: Calliphoridae, Sarcophagidae, Muscidae, Piophilidae (Diptera), Dermestidae, Silphidae and Cleridae (Coleoptera). The most important species were: Diptera - Chrysomya albiceps, Chrysomya putoria, Hemilucilia segmentaria, Hemilucilia semidiaphana (Calliphoridae), Pattonella intermutans (Sarcophagidae), Ophyra chalcogaster (Muscidae), Piophila casei (Piophilidae); Coleoptera - Dermestes maculatus (Dermestidae), Oxyletrum disciolle (Silphidae) and Necrobia rufipes (Cleridae).

Primeira ocorrência de Triplasta atrocoxalis Ashmead (Hymenoptera: Educoilidae) em pupas de Cyrtoneurina pararescita Couri (Diptera: Muscidae) em currais de bovinos no Brasil / First occurrence of Triplasta atrocoxalis Ashmead (Hymenoptera: Eucoilidae) in pupae of Cyrtoneurina pararescita Couri (Diptera: Muscidae) of catlle dung in Brazil

This work reports, for the first time, the occurrence of Triplasta atrocoxalis (Hymenoptera: Eucoilidae) parasitizing pupae of Cyrtoneurina pararescita (Diptera: Muscidae) in catlle dung in Brazil

A checklist of arthropods associated with pig carrion and human corpses in Southeastern Brazil

Necrophagous insects, mainly Diptera and Coleoptera, are attracted to specific stages of carcass decomposition, in a process of faunistic succession. They are very important in estimating the postmortem interval, the time interval between the death and the discovery of the body. In studies done with pig carcasses exposed to natural conditions in an urban forest (Santa Genebra Reservation), located in Campinas, State of São Paulo, southeastern Brazil, 4 out of 36 families of insects collected - Calliphoridae, Sarcophagidae, Muscidae (Diptera) and Dermestidae (Coleoptera) - were considered of forensic importance, because several species were collected in large numbers both visiting and breeding in pig carcasses. Several species were also observed and collected on human corpses at the Institute of Legal Medicine. The species belonged to 17 different families, 6 being of forensic importance because they were reared from human corpses or pig carcasses: Calliphoridae, Sarcophagidae, Muscidae, Piophilidae (Diptera), Dermestidae, Silphidae and Cleridae (Coleoptera). The most important species were: Diptera - Chrysomya albiceps, Chrysomya putoria, Hemilucilia segmentaria, Hemilucilia semidiaphana (Calliphoridae), Pattonella intermutans (Sarcophagidae), Ophyra chalcogaster (Muscidae), Piophila casei (Piophilidae); Coleoptera - Dermestes maculatus (Dermestidae), Oxyletrum disciolle (Silphidae) and Necrobia rufipes (Cleridae).

Diapause, pupation sites and parasitism of the horn fly, Haematobia irritans, in south-eastern Brazil.

In order to verify the occurrence of diapause, preference for pupation sites and hymenopteran parasitism, the pupae of the horn fly, Haematobia irritans (Diptera: Muscidae), were collected from undisturbed cattle dung pats in pastures, and adults of the fly were sampled from cattle in São Paulo State, south-eastern Brazil, from April 1993 to July 1994. Diapause was verified in 7.7% of pupae sampled from pastures in June and July of 1993 and in 9.9% of those sampled in May, June and July of 1994 (overall rate of 9.1%). Approximately 8.3% of the pupae were parasitized by microhymenopterans, mostly Spalangia nigroaenea and S. cameroni (Hymenoptera: Pteromalidae). Horn fly pupae were found almost exclusively inside the pat or in the soil immediately beneath and adjacent to it, and very few were collected elsewhere. Pupa mortality was 54.4% and did not change significantly during the year, but mortality was greater among pupae collected in pastures when compared to those obtained from experimental pats, lacking natural enemies.