Acute oral intragastric pathogenicity and toxicity in mice of Paecilomyces fumosoroseus isolated from whiteflies

Effects on Meccus pallidipennis (Hemiptera: Reduviidae) Eggs Exposed to Entomopathogenic Fungi: Exploring Alternatives to Control Chagas Disease

Meccus pallidipennis Stål is a vector for Chagas disease. The extensive use of pyrethroid insecticides to control triatomines in Mexico has resulted in the development of resistant populations. As an alternative control approach, the effects on M. pallidipennis eggs of two entomopathogenic fungi, Isaria fumosorosea Wize (Hypocreales: Cordycipitaceae) EH-511/3 and Metarhizium anisopliae (Metschn.) Sorokin (Hypocreales: Clavicipitaceae) EH-473/4, were examined. Egg mortality was estimated 1 mo after egg infection, based on hyphal growth and unsuccessful hatching as proxies for infection and death. Sporulation and conidial production rates were also recorded. Mortality rates caused by I. fumosorosea and Me. anisopliae were 92% ± 3.1 and 88% ± 3.7, respectively. Sporulation rate and conidial production were greater in I. fumosorosea than in Me. anisopliae. Transmission electron microscopy revealed hyphal penetration by both fungal species and damage to embryonic epidermal and cuticular cells. Our results demonstrated that I. fumosorosea and Me. anisopliae are promising candidates for controlling M. pallidipennis eggs and offer alternatives to control the transmission of Chagas disease under natural conditions.

Modulation of Human Immune Response by Fungal Biocontrol Agents

Although the vast majority of biological control agents is generally regarded as safe for humans and environment, the increased exposure of agriculture workers, and consumer population to fungal substances may affect the immune system. Those compounds may be associated with both intense stimulation, resulting in IgE-mediated allergy and immune downmodulation induced by molecules such as cyclosporin A and mycotoxins. This review discusses the potential effects of biocontrol fungal components on human immune responses, possibly associated to infectious, inflammatory diseases, and defective defenses.

Lack of pathogenicity and toxicity of the mycoinsecticide Metarhizium anisopliae var. acridum following acute gastric exposure in mice

Metarhizium anisopliae var. acridum, monospore culture EH-502/8 (CNRCB MaPL40), isolated in Mexico from Schistocerca piceifrons ssp. piceifrons (Orthoptera: Acrididae) was tested for acute oral intragastric pathogenicity and toxicity in CD-1 mice. Animals were inoculated with one dose (10(8) conidia/animal) of viable (72 mice), non-viable (24 mice) conidia and compared to 18 control mice. Clinical observations were done daily; mycological and histological tests were performed during necropsies after the inoculation. No mice showed clinical symptoms of illness or died during the study. The fungus was able to persist in some organs until day 3, but did not cause any damage to the host. The gross pathology observed was splenomegaly in mice inoculated with viable and non-viable conidia. Non-germinated conidia, observed in several organs, suggest hematogenous spread, but without any histopathological tissue reaction. Results support the non-pathogenic and non-toxic status of this fungal strain when administered in a single intragastric dose to mice.