Controle biológico de Ancylostoma spp. e de Toxocara canis por fungos nematófagos

• Autor(a) principal: Carvalho, Rogério Oliva
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1468
• topic: Fungo; Ancylostoma SPP.; Toxocara Cati; Fungi; Ancylostoma SPP.; Toxocara Cati; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::MEDICINA VETERINARIA PREVENTIVA

The interaction of man with dogs and cats is not limited to a situation of cohabitation family. These animals also frequent public areas and leisure for the human population and often defecate on these sites. Feces of infected animals, deposited in the environment may become contaminated soil with eggs and larvae of parasitic worms, which often are agents of zoonosis, especially Ancylostoma spp. and Toxocara sp. because they are zoonotic and are most prevalent in dogs.The control of the adult stage of these nematodes is based on the use of anti-helminthic; however, the use of biocontrol agents may be an additional measure reducing the population of preparasitic stages in development in the soil. Among the biocontrol organisms, it is known that nematode- trapping fungi have been effective against nematodes of domestic animals. In order to determine the best fungus for control of Ancylostoma spp., the predatory capacity of nematophagous fungi Duddingtonia flagrans (AC001), Monacrosporium thaumasium (NF34a), M. appendiculatum (CGI), M. sinense (SF53), Arthrobotrys conoides (I-40), A. cladodes (CG719) and A. robusta (I-31) on infective Ancylostoma spp. larvae (L 3) was evaluated. Isolates AC001, I-31 and NF34a were more effective in capturing L3 during the in vitro assay. Isolates were then in vivo evaluated for the capacity to remain viable after passing through the gastrointestinal tract of dogs, while still maintaining their predatory activity against L3. Fungal isolates survived the passage and showed efficient predation 48 h after fungal administration to the dogs (P<0.05). After this time, only the isolate NF34a remained effective up to 96h after administration (P<0.05) and was used in the in vivo test. In order to evaluate the efficiency of the nematophagous fungus Monacrosporium thaumasium (isolate NF34a) in the biological control of dog hookworm, 12 adult animals, average weight between 7 and 19 kg, were separated into groups and kept in 2 different kennels: control group (without fungus) and a group treated with 0.5 g of fungal mycelium per kilogram of body weight, during six months, twice a week (Monday and Thursday). Every 15 days soil samples were collected from each group and examined for infective larvae (L3) in the period between March and September 2008. From June to the end of the experiment (September), means of L3 recovered from the kennel soil of the control group were higher than the means of the kennel soil of the treated group (p>0.05), confirming the action of M. thaumasium against larvae in the soil, and can be therefore considered as an alternative environmental control of Ancylostoma spp. in dogs. In order to determine the best fungus for control of Toxocara canis, an assessment was made of the ovicidal activity of egg-parasitizing fungi Pochonia chlamydosporia (isolates VC1 and VC4) and Paecilomyces lilacinus on Toxocara canis eggs in vitro. All the fungal isolates showed ovicidal activity (type 3 effect) on T. canis eggs and can be considered a potential candidate to biological controller of those nematodes.