Geographical distribution of Amblyomma cajennense (sensu lato) ticks (Parasitiformes: Ixodidae) in Brazil, with description of the nymph of A. cajennense (sensu stricto).

BACKGROUND: Until recently, Amblyomma cajennense (Fabricius, 1787) was considered to represent a single tick species in the New World. Recent studies have split this taxon into six species. While the A. cajennense species complex or A. cajennense (sensu lato) (s.l.) is currently represented by two species in Brazil, A. cajennense (sensu stricto) (s.s.) and Amblyomma sculptum Berlese, 1888, their geographical distribution is poorly known. METHODS: The distribution of the A. cajennense (s.l.) in Brazil was determined by morphological examination of all lots of A. cajennense (s.l.) in two large tick collections of Brazil, and by collecting new material during three field expeditions in the possible transition areas between the distribution ranges of A. cajennense (s.s.) and A. sculptum. Phylogenetic analysis inferred from the ITS2 rRNA gene was used to validate morphological results. Morphological description of the nymphal stage of A. cajennense (s.s.) is provided based on laboratory-reared specimens. RESULTS: From the tick collections, a total 12,512 adult ticks were examined and identified as 312 A. cajennense (s.s.), 6,252 A. sculptum and 5,948 A. cajennense (s.l.). A total of 1,746 ticks from 77 localities were collected during field expeditions, and were identified as 249 A. cajennense (s.s.), 443 A. sculptum, and 1,054 A. cajennense (s.l.) [these A. cajennense (s.l.) ticks were considered to be males of either A. cajennense (s.s.) or A. sculptum]. At least 23 localities contained the presence of both A. cajennense (s.s.) and A. sculptum in sympatry. DNA sequences of the ITS2 gene of 50 ticks from 30 localities confirmed the results of the morphological analyses. The nymph of A. cajennense (s.s.) is morphologically very similar to A. sculptum. CONCLUSION: Our results confirmed that A. cajennense (s.l.) is currently represented in Brazil by only two species, A. cajennense (s.s.) and A. sculptum. While these species have distinct distribution areas in the country, they are found in sympatry in some transition areas. The current distribution of A. cajennense (s.l.) has important implications to public health, since in Brazil A. sculptum is the most important vector of the bacterium Rickettsia rickettsii, the etiological agent of Brazilian spotted fever.

Rickettsial infection in ticks (Acari: Ixodidae) of wild animals in midwestern Brazil.

Ticks collected in the last two decades from free-living and captive wild animals from 28 municipalities of the Brazilian state of Mato Grosso were identified and tested using molecular methods for the presence of rickettsial agents. A total of 4467 ticks (229 larvae, 1676 nymphs, 1565 males, 997 females) representing 27 ixodid species were collected from 235 species of amphibians, reptiles, birds, and mammals from three different ecoregions (Pantanal, Cerrado, and Amazonia). The species Amblyomma parkeri, Amblyomma romitii, Amblyomma varium and Ixodes luciae are reported for the first time in the state of Mato Grosso. Amongst 538 ticks tested by molecular methods for rickettsial infection, we detected 'Candidatus Rickettsia amblyommii' infecting Amblyomma cajennense sensu stricto and Amblyomma coelebs, Rickettsia sp. strain Atlantic rainforest infecting Amblyomma ovale, Rickettsia sp. strain NOD infecting Amblyomma nodosum, and 'Candidatus Rickettsia andeanae' infecting Amblyomma sculptum. Our results represent an impressive expansion of knowledge on tick fauna and rickettsiae and are essential for understanding the ecology of ticks and tick-borne diseases in the Neotropical region, particularly in midwestern Brazil.

Efficacy of Duddingtonia flagrans and Arthrobotrys robusta in controlling sheep parasitic gastroenteritis.

The aim of this study was to evaluate the efficacy of formulations of sodium alginate matrix (pellets) of the nematode predatory fungi, Duddingtonia flagrans (AC001 isolate) and Arthrobotrys robusta (I-31 isolate), in the biological control of sheep gastrointestinal nematode infections. Thirty young Bergamacia ewes were allocated into three groups: In group 1 (control), the animals received 2 g/10 kg of live weight (l.w.) of pellets without fungus; in group 2, each animal received 2 g/10 kg of l.w. of pellets of D. flagrans (0.2 g of fungus/10 kg l.w.); and in group 3, each animal received 2 g/10 kg of l.w. of pellets of A. robusta (0.2 g of fungus/10 kg l.w.). The animals of each group were kept separately under rotational grazing. Pellets, with or without fungi, were mixed with 1 kg animal food and administered twice a week for 6 months. There was no significant difference in mean live weight and packed cell volume among groups (P > 0.05). Mean nematode fecal egg counts (FEC) did not significantly differ between the control and the remaining groups, except in one or two collections, when FEC was higher in the control group than in group 2 and group 3, respectively. The group that received A. robusta pellets needed less salvage anthelmintic treatments. Haemonchus contortus was the predominant species recovered from tracer lambs. The nematophagous fungi, D. flagrans and A. robusta, did not provide satisfactory results in the prophylaxis of parasitic gastroenteritis in sheep, under the conditions of the present study.

Predatory activity of Pochonia chlamydosporia fungus on Toxocara (syn. Neoascaris) vitulorum eggs.

Toxocara (Neoascaris) vitulorum is a gastrointestinal nematode parasite of young ruminants, responsible for high mortality rates in parasitized cattle and buffalo calves. The objective of this work was to compare the predatory capacity under laboratory conditions of four fungal isolates of the nematophagous fungus Pochonia chlamydosporia (VC1, VC4, VC5 and VC12) on T. vitulorum eggs in 2% water-agar (2% WA). T. vitulorum eggs were plated on 2% WA Petri dishes which contained cultured fungal isolates and control plates without fungi. After 10 and 15 days one hundred eggs were removed and classified according to the following parameters: type 1, biochemical and physiological effect without morphological damage to the eggshell, type 2, lytic effect with morphological alteration of the eggshell and embryo and type 3, lytic effect with morphological alteration of eggshell and embryo in addition to hyphal penetration and internal egg colonization. The fungal isolates were effective in the destruction of T. vitulorum eggs presenting the type 3 effect at 10 and 15 days after contact with the fungus. No nematophagous fungi were observed in the control group during the experiment. There was no variation in the predatory capacity of the fungal isolates (P > 0.01) at the intervals of 10 and 15 days. These results indicate that P. chlamydosporia (VC1, VC4, VC5 and VC12) negatively influenced the development of T. vitulorum eggs and can be considered a potential candidate for the biological control of nematodes.

[In vitro evaluation of nematode predacious fungus Duddingtonia fagrans on cyathostomes infective larvae of equines (Nematoda: Cyathostominae)]. / Avaliação in vitro do fungo predador de nematoides Duddingtonia flagrans sobre larvas infectantes de ciatostomíneos de equinos (Nematoda: Cyathostominae).

The predatory capacity of one isolate of nematode-trapping fungus Duddingtonia flagrans (AC001) on infective larvae of cyathostomes was evaluated in laboratorial conditions in medium water-agar 2% (WA 2%). There was significant reduction (p<0.01) of 93.64% in the average of infective larvae of cyathostomes recovered of medium WA 2% at seven day. These results show that the isolated AC001 could be used in the biological control of cyathostomes of horses.

Avaliação in vitro do fungo predador de nematoides Duddingtonia flagrans sobre larvas infectantes de ciatostomíneos de equinos (Nematoda: Cyathostominae) / In vitro evaluation of nematode predacious fungus Duddingtonia flagrans on cyathostomes infective larvae of equines (Nematoda: Cyathostominae)

A capacidade predatória de um isolado de fungo predador de nematoides Duddingtonia flagrans (AC001) sobre larvas infectantes de ciatostomíneos foi avaliada em condições laboratoriais em ensaio experimental em meio ágar-água 2% (AA 2%). Houve redução significativa (p < 0,01) de 93,64% na média de larvas infectantes de ciatostomíneos recuperadas do meio AA2%, ao final de sete dias. Os resultados desse ensaio evidenciam que o isolado fúngico AC001 poderia ser utilizado no controle biológico de ciatostomíneos de equinos.

The predatory capacity of one isolate of nematode-trapping fungus Duddingtonia flagrans (AC001) on infective larvae of cyathostomes was evaluated in laboratorial conditions in medium water-agar 2% (WA 2%). There was significant reduction (p < 0. 01) of 93.64% in the average of infective larvae of cyathostomes recovered of medium WA 2% at seven day. These results show that the isolated AC001 could be used in the biological control of cyathostomes of horses.

Resistance of different fungal structures of Duddingtonia flagrans to the digestive process and predatory ability on larvae of Haemonchus contortus and Strongyloides papillosus in goat feces.

The dynamics of the passage of conidia, chlamydospores, and mycelia of the fungus Duddingtonia flagrans through the digestive tracts of goats was evaluated. Four groups with five goats each were formed. In the group conidia, each animal received 1 x 10(6) D. flagrans conidia per kilogram of live weight. In the group chlamydospore, each animal received 1 x 10(6) chlamydospores per kilogram of live weight. In the group mycelia, each animal received 1 g of mycelium mass per kilogram of live weight. In the control group, the animals received no fungal structure. Feces were obtained 3 h before and 12, 24, 30, 36, 42, 48, 60, 72, 84, and 96 h after the inoculation. The feces were placed in Petri dishes containing water-agar. The Petri dishes were examined to detect the fungus and trapped nematodes. A second trial evaluated the effect of the fungal structures on the number of gastrointestinal larvae of Haemonchus contortus and Strongyloides papillosus harvested from the fecal cultures of the goats. The feces were obtained from the goats in the 12-24, 24-30, 30-36, 42-48, 60-72, 72-84, and 84-96 intervals after the inoculation. D. flagrans survived the digestive process of the goats and maintained its predatory activity, being observed from 12 to 96 h before inoculation in the animals that received chlamydospores and conidia.

Interaction and ovicidal activity of nematophagous fungus Pochonia chlamydosporia on Taenia saginata eggs.

The ovicidal activity of the nematophagous fungi Pochonia chlamydosporia (isolates VC1 and VC4), Duddingtonia flagrans (isolate AC001) and Monacrosporium thaumasium (isolate NF34) on Taenia saginata eggs was evaluated under laboratory conditions. T. saginata eggs were plated on 2% water-agar with fungal isolates and controls without fungus and examined after 5, 10 and 15 days. At the end of the experiment P. chlamydosporia showed ovicidal activity against T. saginata eggs (p<0.05), mainly for internal egg colonization with results of 12.8% (VC1) and 2.2% (VC4); 18.1% (VC1) and 7.0% (VC4); 9.76% (VC1) and 8.0% (VC4) at 5, 10 and 15 days, respectively. The other fungi showed only lytic effect without morphological damage to the eggshell. Results demonstrated that P. chlamydosporia was effective in vitro against T. saginata eggs unlike the other fungi.

[In vitro observation of the action of isolates of the fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamydosporium on the eggs of Ascaris lumbricoides (Linnaeus, 1758)]. / Observação in vitro da ação dos isolados fúngicos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides (Lineu, 1758).

The in vitro action of the nematophagous fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamydosporium on eggs of Ascaris lumbricoides was observed. After 7, 10 and 14 days of interaction, the fungus showing most promise for use in biologically control over Ascaris lumbricoides was Verticillium chlamydosporium (26-30%). The other fungi did not present satisfactory results.

[The relationship between larvae recovered of pasture and counting eggs per grams of feces (epg) of the gastrointestinal nematodes of cattle in the Microrregion of Viçosa, State of Minas Gerais]. / Relação entre larvas recuperadas da pastagem e contagem de ovos por gramas de fezes (opg) de nematóides gastrintestinais de bovinos na Microrregião de Viçosa, Minas Gerais.

Eight calves with one year old approximately, Holstein-zebu cross-breeding, were stocked in paddock to analysis the relation between the eggs per grams of feces (EPG) and larvae number recovered of pastures, from February to September 2005, at municipality of Viçosa, Zona da Mata region, State of Minas Gerais, Brazil. During this time, feces and pastures were collected for examination of EPG and larvae recovered from pastures, respectively. The genera Cooperia, Haemonchus and Oesophagostomum larvae were harvested in paddock until 20 centimeters and between 20 and 40 cm far distance of fecal cake. The genus Cooperia (60.97%) was the most prevalent in the pastures. In coprocultures, Haemonchus (42.65%) was the most prevalent genus of nematode. The coefficient of correlation of the larvae recovered of pasture and the EPG was not significant (P < 0.05). It can indicate that this relation can be influenced possibly by several factors related on the nematodes, the host and the climate conditions.

Observação in vitro da ação dos isolados fúngicos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides (Lineu, 1758) / In vitro observation of the action of isolates of the fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamydosporium on the eggs of Ascaris lumbricoides (Linnaeus, 1758)

Observou-se a ação in vitro dos fungos nematófagos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides. Após sete, dez e quatorze dias de interação, o fungo promissor a ser utilizado no controle biológico de Asaris lumbricoides foi o Verticillium chlamydosporium (26-30 por cento). Os outros fungos não foram satisfatórios.

The in vitro action of the nematophagous fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamydosporium on eggs of Ascaris lumbricoides was observed. After 7, 10 and 14 days of interaction, the fungus showing most promise for use in biologically control over Ascaris lumbricoides was Verticillium chlamydosporium (26-30 percent). The other fungi did not present satisfactory results.

[Evaluation of nematode predacious fungus Duddingtonia flagrans on infective Haemonchus contortus and Strongyloides papillosus larvae of goats]. / Avaliação do fungo predador de nematóides Duddingtonia flagrans sobre larvas infectantes de Haemonchus contortus e Strongyloides papillosus de caprinos.

One brazilian isolate of nematode-trapping fungus Duddingtonia flagrans AC 001 was evaluated regarding the capacity of supporting passage through the gastrointestinal tract of goats without losing the ability to entrap infective Haemonchus contortus and Strongyloides papillosus larvae (L3). Ten saneen goats of eight months old, males and infected naturally were divided in two groups of five animals. In the group 1, the animals received orally 20 g of pellets of the D. flagrans. In the group 2 (control), the animals received orally 20 g of pellets without fungi. Fecal Samples were collected at 14, 20, 24, 36 and 46 hours after the treatments and were allocated in fecal cultures at 25 degrees C during fifteen days. There was significant reduction (p<0.05) of the average number of S. papillosus larvae recovered of the fecal cultures in the animals treated with fungus when compared with the control animals at 14 and 46 hours, in the end of the experiment, this difference was 82.3%. There was significant reduction (p<0.05) of the average number of H. contortus larvae recovered of the fecal cultures in the animals treated with fungus when compared with the control animals at 14, 20 and 46 hours, in the end of the experiment, this difference was 59.3%. Such evidences confirm the transit of these fungi pellets by the digestive tract of the goats without loss of the predatory viability on L3 of H. contortus and S. papillosus.

[Viability of nematophagous fungi Arthrobotrys robusta, Duddingtonia flagrans and Monacrosporium thaumasium after sporulation in different culture media]. / Viabilidade sobre larvas infectantes de Ancylostoma spp. dos fungos nematófagos Arthrobotrys robusta, Duddingtonia flagrans E Monacrosporium thaumasium após esporulação em diferentes meios de cultura.

Due to the shortage of studies that indicate the culture mediums that optimize the sporulation of namatophagous fungi for use in researche, the sporulation of the fungal isolates A. robusta (I31), D. flagrans (CG768) and M. thaumasium (NF34A) was evaluated in laboratorial conditions for 10 days in the means water-agar 2% (WA 2%), potato-dextrose-agar 2% (PDA 2%), corn-meal-agar 2% (CMA 2%) and yeast-phosphate-sulphate-sucrose-agar (YPSSA). The largest conidia production (P < 0.05) for the isolate CG768 happened in BDA 2% while in the isolates I31 and NF34A produced larger conidia number in YPSSA (P < 0.05). The viability of the conidia to prey infective Ancylostoma spp. larvae did not lose its effectiveness (P < 0.05) independent of the culture medium. The middle of culture did not influence in the viability of the conidia (P > 0.05).

Identification of an expressed gene in Dipylidium caninum.

Recombinant DNA studies have been focused on developing vaccines to different cestodes. But few studies involving Dipylidium caninum molecular biology and genes have been done. Only partial sequences of mitochondrial DNA and ribosomal RNA gene are available in databases. Any molecular work with this parasite, including epidemiology, study of drug-resistant strains, and vaccine development, is hampered by the lack of knowledge of its genome. Thus, the knowledge of specific genes of different developmental stages of D. caninum is crucial to locate potential targets to be used as candidates to develop a vaccine and/or new drugs against this parasite. Here we report, for the first time, the sequencing of a fragment of a D. caninum expressed gene.

Identification of specific male and female genes in adult Ancylostoma caninum.

The hookworm Ancylostoma canium represents a serious health problem, not only for animals but also for humans. These blood-feeding parasites produce various proteolytic enzymes in order to digest the host hemoglobin. The female worm ingests more blood than does the male. It is not known whether this difference is accompanied by expression of sex-specific proteinases. The identification of new genes related either to the developmental process of maturation of each sex or to the proteinases secreted by these worms could provide researchers with new tools to be used in control programs for this important parasite. The differential-display technique was used to compare the gene expression patterns of adult male and female worms in order to find specific genes that could be used as new targets in the control strategies for this parasite.