ABSTRACT
A pulga Ctenocephalides felis felis é um parasita causador dermatites alérgicas e também pode transmitir diversos agentes etiológicos aos animais domésticos e aos homens. O objetivo deste trabalho foi verificar o desenvolvimento do fungo sobre a cutícula da pulga, através da microscopia eletrônica de varredura. Os isolados fúngicos testados foram o Metarhizium anisopliae 959 e Beauveria bassiana 986, ambos na concentração 10(8) conídios/ml. Após a exposição dos isolados fúngicos no período de duas, 15, 26 e 96 horas , o material foi processado para a microscopia eletrônica de varredura. Com a obtenção das micrografias, pode-se observar que com 2 horas após exposição aos fungos, os conídios estavam aderidos por toda a cutícula, situando-se preferencialmente nas membranas intersegmentais do abdome. Com 15 horas observou-se a formação do tubo de germinação e a cabeça do apressório e após 26 horas foi possível observar as ramificações e o engrossamento das hifas sobre a cutícula das pulgas. Os resultados indicam que os fungos testados foram capazes de se desenvolver sobre a cutícula de C. f. felis.
The flea Ctenocephalides felis felis is a parasite that causes allergic dermatitis and also may transmit etiologic agents to domestic animals and humans. This study investigated by scanning electron microscopy the development of entomopathogenic fungi on flea cuticle. Fleas were exposed to conidia (10(8) ml-1) of Metarhizium anisopliae (isolate 959) or Beauveria bassiana (isolate 986). Following standard protocols for electron microscopy, the specimens were prepared 2, 15, 26 and 96 h after infection. The micrography revealed that 2 h after fungus exposure, conidia attachments encompassed the entire flea cuticle, especially on abdominal intersegmental membranes. The emergence of germ tubes and appressoria formation occurred at 15 h, thickening and branching of hyphae on the flea cuticle was noted at 26 h. Therefore, both of these fungal isolates were able to develop on cuticular surfaces of C. f. felis.
Subject(s)
Animals , Beauveria/growth & development , Metarhizium/growth & development , Siphonaptera/microbiology , Beauveria/ultrastructure , Microscopy, Electron, Scanning , Metarhizium/ultrastructureABSTRACT
Rhipicephalus sanguineus is responsible for transmitting several pathogenic agents, such as: Babesia sp. and Ehrlichia sp.. This species is known as the brown dog tick and has wide geographical distribution. The purpose of this work was to evaluate the pathogenicity of biological formulations of Beauveria bassiana and Metarhizium anisopliae applied to the fed nymphs and adults of R. sanguineus under laboratory conditions. The following treatments were evaluated: control, distilled water with tween 80, emulsible concentrated, cellulose polymerized gel, fungus mixed with emulsible concentrated, fungus mixed with cellulose polymerized gel and fungus mixed with emulsible concentrated and cellulose polymerized gel. Each treatment was repeated ten times. The survival of fed nymphs and unfed adults was evaluated on the 5th, 10th, 15th and the 20th days after treatments. Significant differences were observed between the treatments (p<0.05). The treatment with M. anisopliae mixed with emulsible concentrated and cellulose polymerized gel showed the lower survival on the 15th and 20th days after treatment. We can conclude that the fungi formulation is harmful to fed nymphs and unfed adults of R. sanguineus in vitro, on this account it is suggested its use for the microbial control of this tick.
