Interaction of the nematophagous fungus Pochonia chlamydosporia and Parascaris equorum eggs in different culture media.

Research involving the use of nematophagous fungi in the biological control of parasites of interest to veterinarians has occurred over recent years, with promising results. This article reports the infection of Parascaris equorum eggs by the fungus Pochonia chlamydosporia (isolates VC1 and VC4). Six groups were formed for each isolate, with six different culture media: 2% water-agar (2% WA); agar-chitin (AC); YPSSA (yeast extract, K2HPO4, MgSO4 ·7H2O, soluble starch); AELA extract (starch + water + agar); 2% corn-meal-agar (2% CMA); and 2% potato dextrose-agar (2% PDA). A total of 1000 eggs of P. equorum were transferred to each plate containing isolates grown for a period of 7 days (treatment group). Also, 1000 eggs were added to each plate without fungus (controlgroup). The plates were kept in an environmental chamber at 25 °C in the dark for 21 days. After, we analyzed the effects on ovicidal activity: effect 1 (accession shell); effect 2 (penetration hyphae); and effect 3 (destruction of the eggs). No differences were observed in the destruction of eggs between the two isolates. The decreasing effectiveness of the different culture media was: PDA (38.9%); CMA (38.3%); WA (36.7%); YPSSA (36.45%); and AC (32.5%). The highest percentage egg destruction was observed when the strains were grown in culture medium AELA (44.9%); this was the best medium.

Effect of the fungus Pochonia chlamydosporia on Echinostoma paraensei (Trematoda: Echinostomatidae).

Echinostoma paraensei is a trematode of the genus Echinostoma that causes echinostomiasis in humans. The objectives of this study were to: evaluate the ovicidal activity of the nematophagous fungus Pochonia chlamydosporia (VC1 and VC4) on a solid medium 2% water-agar (2% WA) against E. paraensei eggs (assay A); evaluate ovicidal effect (destruction of eggs) of the isolate VC4 in supplemented culture media (assay B); and evaluate the ovicidal ability of the crude extract (VC4) on E. paraensei eggs (assay C). Eggs of E. paraensei (assay A) were placed in Petri dishes containing 2% WA with an isolate of the fungus P. chlamydosporia (VC1 and VC4) grown for 10 days, and without fungus as a control and evaluated regarding their destruction. In assay B, eggs of E. paraensei were placed in Petri dishes with different supplemented culture media and with VC4 isolate and the destruction of eggs was examined at the end of 25 days of interaction. In assay C, effects of the crude extract of P. chlamydosporia (VC4) on eggs were evaluated at the end of 7 days. In assay A, there was no difference (p>0.05) in ovicidal activity among the tested isolates (VC1 and VC4); however, the highest percentage for ovicidal activity (type 3 effect) was demonstrated by the isolate VC4. In assay B, the culture medium starch-agar showed the best results for the destruction of the eggs, with a percentage of 46.6% at the end of the assay. In assay C, the crude extract of VC4 was effective in the destruction of E. paraensei eggs, with a percentage reduction of 53%. The results of this study demonstrate that a rich culture medium with a greater availability of carbon and nitrogen may interfere directly in the predatory characteristics of ovicidal fungi.

Population dynamics of Libyostrongylus dentatus and L. douglassii of ostriches raised in the Northern Rio de Janeiro State, Brazil.

Libyostrongylus genus contains three species of gastrointestinal nematodes that infect ostriches. Of these, only Libyostrongylus douglassii has been implicated in diseases and lower productivity. A morphological diagnosis method allowing the discrimination of infective larvae of L. douglassii and Libyostrongylus dentatus and the evaluation of eggs per gram of feces (EPG) was used to determine the population dynamics of both species from two ostrich farms located in the northern region of the state of Rio de Janeiro, Brazil. The presence of these nematodes was monitored every 15 days for two years. The average EPG was 4631 and 587 on farms 1 and 2, respectively. Overall, the highest values of EPG were associated with the rainy season on both farms. However, only on farm 1 the rainy season correlated statistically with EPG. Both species of Libyostrongylus occurred on both farms with a higher predominance (86%) of L. douglassii on farm 1, whereas the distribution of infection on farm 2 was more heterogeneous with a slight predominance of L. douglassii. The infection and the prevalence of these species may vary considerably according to the farm facilities, management adopted, and season.

First report of the activity of predatory fungi on Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) first-stage larvae.

The nematode Angiostrongylus cantonensis causes eosinophilic meningoencephalitis in humans and thus alternative methods of control should be studied. The objective of this work was to evaluate the predatory capacity of eight fungal isolates of the species Duddingtonia flagrans (AC001, CG768 and CG722), Monacrosporium thaumasium (NF34), M. sinense (SF53) and Arthrobotrys robusta (I31), A. cladodes (CG719) and A. conoides (I40) on first-stage larvae (L1) of A. cantonensis under laboratory conditions. The treated groups contained 1000 conidia of the fungal isolates and 1000 A. cantonensis L1 in Petri dishes containing 2% water-agar medium (2% WA). The control group (without fungi) contained only 1000 A. cantonensis L1 in 2% WA. Evidence of predation was observed at the end of 7 days. Percentage reductions in L1 were: AC001, 82.8%; CG768, 71.0%; CG722, 72.8%; NF34, 86.7%; SF53, 89.7%; I40, 48.3%; CG719, 84.7%; and I31, 80.4%. No significant difference was observed (p>0.01) between the actions of the isolates used; however, a difference was noted (p<0.01) in relation to the control group. The results of the present work, confirm previous reports of the effectiveness of the fungi D. flagrans, M. thaumasium, M. sinense and A. robusta in controlling larvae of potentially zoonotic nematodes, this being the first report on A. cantonensis L1.

Efficacy of albendazole and moxidectin and resistance to ivermectin against Libyostrongylus douglassii and Libyostrongylus dentatus in ostriches.

Anthelmintic resistance has emerged globally as a problem amongst nematode of livestock and has been particularly well documented in equine and small ruminants. There are no studies regarding the efficacy of anthelmintics against the hematophagous nematodes in ostriches, Libyostrongylus dentatus; and just a few on L. douglassii. Here the efficacy of albendazole, ivermectin and moxidectin were evaluated against these two species in an ostrich farm in Minas Gerais state, Brazil. The feces were collected on the day of treatment and after 13 days of an oral dose of albendazole (6 mg/kg), or an injected dose (0.2mg/kg) of ivermectin or moxidectin. The fecal egg count reduction test and coprocultures were performed to determine possible resistance against the drugs used. An efficacy of 60% was found for ivermectin, while albendazole and moxidectin were 100% effective. Both worm species appeared to have reduced sensitivity to ivermectin.

Occurrence of nematodes and anthelmintic management of ostrich farms from different Brazilian states: Libyostrongylus douglassii dominates mixed infections.

Ostriches were imported to Brazil in the early 1990s without appropriate parasite control leading to a co-importation of parasites. Libyostrongylus douglassii, Libyostrongylus dentatus and Codiostomum struthionis are nematodes of the ostriches that have been reported on some Brazilian farms but no national survey has been performed. Moreover, little is known about anthelmintic usage to control these parasites in Brazil. Therefore, the occurrence of L. douglassii, L. dentatus and C. struthionis and the anthelmintic management practices in Brazilian ostrich farms were studied. A questionnaire about management practices and information on how to collect, store and ship feces to the laboratory were sent to 17 farms located in 9 Brazilian states. Received fecal samples were submitted to fecal cultivation and larval harvested. Infective larvae were morphologically analyzed and quantified. The majority of the farms (88%) used an anthelmintic at least once a year. Ivermectin was the principal anthelmintic. Libyostrongylus sp. and C. struthionis were found in samples from 76 and 18% of the examined farms, respectively. The presence of L. douglassii (61-97%) was higher than L. dentatus (3-57%) and C. struthionis (2-30%). At the farm level, both species of Libyostrongylus were always found together. Sheath tail measurements of their infective larvae were crucial for morphological diagnosis. L. dentatus and L. douglassii are well adapted to Brazil and are widely distributed in the Brazilian territory, proving that this mixed infection in Brazilian ostrich's farms is common.