Mechanism of infection and colonization of Rhipicephalus sanguineus eggs by Mertarhizium anisopliae as revealed by scanning eletron microscopy and histopathology

Garcia, Marcos Valério; Monteiro, Ana Ruth Macêdo; Szabo, Matias Juan Pablo; Prette, Nancy; Bechara, Gervásio Henrique

doi:10.1590/s1517-83822005000400012

Cited by 34 publications

(25 citation statements)

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“…A similar result was found in a study on the infection of eggs of Rhipicephalus sanguineus by M. anisopliae (GARCIA et al, 2005). This shows that both fungi present the same process of infection.…”

Section: Infection Of P Americana Females and Oothecaesupporting

confidence: 88%

“…Electron microscopy scanning of pathogenic action of isolate JAB 42 A. westerdijkiae in P. americana oothecae Forty five P. americana oothecae aged between 7 to 15 days were immersed for three minutes in suspension containing 6 x 10 8 con./ mL of the isolate JAB 42 of A. westerdijkiae according to the protocol described by GARCIA et al (2005). It was used the methodology of SANTOS & MAIA (1997), described below, to conduct the electron micrographs.…”

Section: Infection Of P Americana Females and Oothecaementioning

confidence: 99%

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Pathogenicity of Aspergillus westerdijkiae to females and oothecae of Periplaneta Americana

et al. 2015

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Section: Infection Of P Americana Females and Oothecaesupporting

confidence: 88%

Section: Infection Of P Americana Females and Oothecaementioning

confidence: 99%

Pathogenicity of Aspergillus westerdijkiae to females and oothecae of Periplaneta Americana

et al. 2015

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“…Resultados semelhantes foram obtidos por Garcia et al (2005) Na análise histológica das larvas do grupo-teste, a adesão conidial pôde ser observada pela presença de pequenos grumos negros, aderidos na região posterior do corpo da larva (Fig. 1A), mas no, grupo-controle, nada foi encontrado (Fig.…”

Section: Resultado E Discussãounclassified

Eventos externos e internos da infecção de larvas e ninfas de Rhipicephalus sanguineus por Metarhizium anisopliae

Garcia

Monteiro

Szabó

et al. 2008

Arq. Bras. Med. Vet. Zootec.

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RESUMOExaminaram-se a adesão, a germinação, a penetração e a colonização de larvas e ninfas de Rhipicephalus sanguineus por Metarhizium anisopliae, assim como as lesões infringidas pelo fungo nas respectivas fases do ciclo de vida do ácaro. Realizaram-se infecções experimentais em 11 grupos contendo 250 larvas e 11 grupos contendo 75 ninfas de R. sanguineus, por meio de banho, durante três minutos sob agitação manual, em suspensão contendo 10 8 conídios/ml do fungo. Nos grupos-controles, o banho foi realizado usando o veículo da suspensão. Larvas e ninfas foram processadas para um estudo histopatológico e de microscopia eletrônica de varredura nos seguintes tempos após a infecção: uma e 18 horas, e um, dois, três, quatro, cinco, seis, sete, nove e 11 dias. A germinação dos conídios ocorreu em até 18 horas pós-inoculação, e o fungo penetrou nas larvas e ninfas através do tegumento, dois e três dias após a infecção, respectivamente. Após penetração, o fungo invadiu o corpo das larvas e ninfas, promovendo uma colonização difusa, sem preferência aparente por tecidos específicos. Lesões significativas não foram observadas. A morte das larvas e ninfas ocorreu no terceiro e quarto dias pós-infecção, e a esporulação do patógeno sobre o cadáver foi iniciada no sexto dia pós-infecção.Palavras-chave: cão, carrapato, controle biológico, controle microbiano, fungo entomopatogênico ABSTRACT The adhesion, germination and colonization of Rhipicephalus sanguineus larvae and nymphs by Metarhizium anisopliae as well as the lesions caused by the fungus were studied. For this purpose, 11 groups of 250 larvae each and 11 groups of 75 nymphs each were bathed during 3 minutes under manual shaking in a 108 conidia/ml suspension. Corresponding control groups were bathed only in the suspension vehicle. Ticks were also submitted to both conventional microscopy and scanning eletronmicrocopy analyses at several post-infection periods (1 and 18 hours and 1, 2, 3, 4, 5, 6, 7, 9, and 11 days)

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“…In surveys conducted by Kaaya & Garcia [26,27] it was described that suspensions of M. Anisopliae in high concentrations resulted in considerable reduction in egg hatching rate of engorged female ticks, when compared to the control.…”

Section: Discussionmentioning

confidence: 99%

Selection of Filamentous Fungi for the Biocontrol of Rhipicephalus (Boophilus) Microplus in Tropical Regions

Abrão¹

2017

JDVAR

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Rhipicephalus microplus is an ectoparasite that causes significant losses to livestock due to spoliation of cattle and the high cost of current control techniques. The control of this parasite is chemically accomplished, but the incorrect use of this method is causing resistance in this species. An alternative to control would be the use of fungi, as they do not need to be ingested by the host, being only necessary to have contact with the target such that it can grow and colonize. Thus, the present study aimed to isolate, identify and select efficient fungal strains in the biological control of Rhipicephalus microplus in tropical weather, such as found in Brazil. Soil and Brachiaria brizantha forage samplings were carried out for isolation, quantification and identification of fungal species. Engaged females of R. microplus were collected for the bioassay of colonization rate, hatchability of eggs and production of mycotoxins. A total of 2x10 -3 CFU g -1 fungi were found and five genera were identified. Aspergillus spp. was the most frequent genus amidst the isolates obtained from both environments. The forage presented a greater amount of fungal colonies.g -1 when compared to the soil. We identified entomopathogenic, saprophytic, pathogenic and keratinophilic species with biotechnological potential as well as for use for biological control. Aspergillus was the most prevalent genus in both soil and forage of tropical regions. Elevated fungal variety was observed in the ecosystems we studied. Metarhizium anisopliae efficiently colonized the parasites in an 80% rate, and differed from other treatments (p< 0.01). These study open doors for investigations concerning the evaluation of other fungi colony counting's, forms of manipulation and other bioassays.Keywords: Dairy cattle; Tick; Biological control; In vitro tests; Microbiology; R. microplus; Rhipicephalus microplus; Aspergillus IntroductionTicks are ectoparasites characterized mainly by blood feeding, independently of family, genus or species [1], and the species Rhipicephalus microplus causes substantial losses for beef and milk cattle due to spoliation of cattle and the high cost of current control techniques [2][3][4]. These parasites have a lifecycle in the host and another in the pasture, and only females fill with blood, after they release themselves from the host and fall to the ground, where they seek a dark and humid place, suitable to lay their eggs [5]. The weather conditions in Brazil contribute to the development of the ectoparasite, allowing ticks populations to be virtually established in the entire country [6]. The chemical control is currently the preferred for the combat of ticks; however, the incorrect use of this method favors the occurrence of multiple or cross resistance [7,8]. In addition, the permanence of residues in animals and their products, thereby, alternatives to the control of this parasite are highly relevant [9].There are several natural enemies that contribute to the control of this parasite in the host or in the soi...

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Mechanism of infection and colonization of Rhipicephalus sanguineus eggs by Mertarhizium anisopliae as revealed by scanning eletron microscopy and histopathology

Cited by 34 publications

References 16 publications

Pathogenicity of Aspergillus westerdijkiae to females and oothecae of Periplaneta Americana

Pathogenicity of Aspergillus westerdijkiae to females and oothecae of Periplaneta Americana

Eventos externos e internos da infecção de larvas e ninfas de Rhipicephalus sanguineus por Metarhizium anisopliae

Selection of Filamentous Fungi for the Biocontrol of Rhipicephalus (Boophilus) Microplus in Tropical Regions

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