Ovicidal and toxicological effect of hydroalcoholic extracts of Euphorbia milli var splendens, Synadenium carinatum Boiss and Tagetes minuta L. against Ancylostoma spp.: In vitro study.

Nematodes of the Ancylostomidae family consist of important parasitic species. The control of such parasitosis represents an important challenge, given the constant high rate of reinfection of some hosts, among which the domestic dog, as well as the high environmental contamination. Another factor that can have a negative influence is the toxicity of the chemicals used for environmental decontamination, highlighting the need to design research to identify new control strategies for this parasitosis, among which the use of plant extracts. Thus, the objective of this research was to evaluate the toxicity and ovicidal activity of hydroalcoholic extracts obtained by percolation of three plants: Tagetes minuta L., Euphorbia milli var splendens (Bojer ex Hook.) Ursch & Leandri and Synadenium carinatum Boiss, against Ancylostoma spp. In addition, these extracts were tested at different concentrations for toxicity against Artemia salina L. and Allium cepa L. It was observed that the hydroalcoholic extract of all plant species evaluated induced moderate ovicide activity at all the tested concentration, with emphasis on E. milii, which was the only plant species that presented significantly low toxicity in the concentration of 12.5 µL/mL when compared to the other species evaluated.

Willis method modification with a view to improving routine coproparasitological diagnosis

Intestinal parasites still cause high morbidity and mortality, due to poor hygiene and sanitary conditions, and therefore indiscriminate treatment has been routine practice advocated by the Public Health staff. Although there is a consensus regarding the need to diagnose such diseases, this is not performed with the necessary care, due to great demand and the lack of a wide ranged and highly sensitive technique. In this sense, most clinical laboratories use routine methods for fecal examination such as the Lutz sedimentation or modified Ritchie methods, which are complete and easy to execute, but do not have adequate sensitivity to detect low density eggs and protozoan cysts, especially when there is a predominance of low parasite burdens. In contrast, there are methods that are based on the flotation of low density developmental forms, namely, the Willis method (NaCl flotation d=1.120), which is rapid, easy to perform and allows high density egg flotation but with low sensitivity for protozoan cysts; and the Faust method, which is based on centrifugal flotation of developmental forms in a 33% ZnSO4 (d=1.200) solution, but with the disadvantage of being lengthy and requiring a centrifuge. In this study, we verified the applicability of introducing an alteration in the Willis method, which consisted in the substitution of NaCl by ZnSO4 in order to combine the advantages of this method with the Faust method. 208 samples were assessed by the Willis and Ritchie methods and by the proposed method (modified Willis). The latter proved superior to the other two (ρ <0,0001 ­ X2) regarding the detection of protozoan cysts, but similar to the Ritchie method in regard to other diagnosed parasites, therefore demonstrating the high potential for the introduction of this modified method in the routine of fecal diagnosis