Pythium insidiosum belongs to the phylum Oomycota. It is capable of infecting mammals causing a serious condition called pythiosis, which affects mainly horses in Brazil and humans in Thailand. The objective of the present study was to verify the in vitro anti-P. insidiosum activity of a biogenic silver nanoparticle (bio-AgNP) formulation. The in vitro assays were evaluated on P. insidiosum isolates (n = 38) following the M38-A2 protocol. Damage to the P. insidiosum hyphae ultrastructure was verified by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Bio-AgNP inhibition concentrations on P. insidiosum isolates ranged from 0.06 to 0.47 μg/ml. It was observed through SEM that P. insidiosum hyphae treated showed surface roughness, as well as cell walls with multiple retraction areas, loss of continuity, and rupture in some areas. The TEM of treated hyphae did not differentiate organelle structures; also, the cellular wall was rarefied, showing wrinkled and partly ruptured borders. The bio-AgNP evaluated has excellent in vitro anti-P. insidiosum activity. However, further studies on its in vivo action are necessary as so to determine the possibility of its use in the treatment of the disease in affected hosts.

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Pythiosis is a rapidly progressing disease that can be lethal to affected individuals due to resistance to available therapeutic protocols. The disease affects mammals, with the largest number of reports in horses and humans. The present study investigated the activity of biogenic silver nanoparticles (bioAgNP) in the treatment of experimental pythiosis. The disease was reproduced in nine female 90-day-old New Zealand rabbits. Animals were divided into three groups: group1 (control, n = 3) daily and topically treated with a nonionized gel-based formulation and 1 ml of sterile distilled water intralesion administered every 48 hours; group 2 (n = 3), daily and topically treated with gel-based formulation containing 1 μg/ml bio-AgNP; group 3 (n = 3), treated with 1 ml bio-AgNP in 1 μg/ml aqueous solution intralesion administered every 48 hours. Animals were treated for 45 days, and the area of subcutaneous lesions was measured every 5 days. Results showed that groups 2 and 3 differed from control group (P < .05) in the lesion area, as well as the amount of hyphae within the lesions. It was observed that lesions of treated animals (groups 2 and 3) did not differ from each other, showing that the application route did not influence the regression of lesions. However, it was observed that one animal from group 2 reached clinical cure at 35 days of treatment. This research is pioneer in the application of nanocomposites for the treatment of experimental pythiosis and showed that bio-AgNP can be powerful allies of integrative medicine and can be included in pythiosis therapeutic protocols.

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This study investigated the frequency of oocysts of Cryptosporidium spp. in feces from dogs and cats in five municipalities in the southern region of the state of Rio Grande do Sul. The risk factors associated with infection were also investigated. Feces samples from 110 dogs and 18 cats were stained using the auramine method. At the time of feces sampling, a questionnaire with semi-open-ended questions was applied to the animal guardians and all data obtained underwent statistical analysis. The real frequency of oocysts of Cryptosporidium spp. was 24.63% (27 dogs and two cats). Only four samples of dog feces were diarrheic and no presence of oocysts was observed in any of them. Variables that represented risk factors for infection were: homemade food, untreated water, circulation of animals on grassy terrain and living in the same environment as other animals (cattle). The results made it possible to inferring that within the population studied, the frequency of parasitism due to Cryptosporidium spp. in dogs was relevant and emphasize the asymptomatic nature of this infection. The adopting control measures are highlighted, particularly in relation to variables that represent risk factors for this infection.

Pythium insidiosum is an important aquatic oomycete which can cause pythiosis in both animals and humans. This microorganism shows low susceptibility to antifungal drugs available. This study analyzed the in vitro antimicrobial activity of Melaleuca alternifolia in its free oil (FO) and nanoemulsion (NE) formulations against Brazilian P. insidiosum isolates. The antimicrobial activity evaluation was performed by the broth microdilution method according to CSLI M38-A2 document adapted to phytopharmaceuticals. Twenty-six P. insidiosum isolates were evaluated, and the minimum inhibitory concentration was determined at 100 % growth inhibition. Melaleuca alternifolia essential oil or FO was obtained commercially. The NE containing 1 % M. alternifolia essential oil was prepared by the spontaneous emulsification method. All P. insidiosum isolates evaluated showed minimum inhibitory concentrations (MIC) ranging from 531.5 to 2125 μg/mL for the FO formulation; MIC and MIC showed values between 1062.5 and 2125 μg/mL, respectively. When the NE formulation was evaluated, MIC values ranged from 132.7 to 2125 μg/mL and both MIC and MIC corresponded to 1062.5 μg/mL. FO and NE formulations of M. alternifolia showed antimicrobial activity against P. insidiosum. This study demonstrated that M. alternifolia oil can be an additional therapy in pythiosis treatment; however, further studies are needed to evaluate the applicability of the plant essential oils in the treatment of clinical pythiosis.

RESUMO Este trabalho investigou a influência da adiposidade em éguas Crioulas gestantes sobre o peso e o acúmulo de gordura de seus potros do nascimento aos quatro meses de vida. Foram avaliadas 28 éguas Crioulas no terço final de gestação, divididas em dois grupos (normais e obesas) quanto ao peso, à circunferência de pescoço, à altura da crista do pescoço e à gordura subcutânea na base da cauda, bem como quanto à relação dessas medidas com as de seus potros, do parto aos 120 dias de idade. Os filhos de éguas obesas apresentaram maior deposição de gordura na base da cauda, no segundo mês (P<0,05), e na crista do pescoço (P=0,0022), no quarto mês de idade. Houve correlação positiva da altura da crista do pescoço da égua com o peso dos potros ao nascer (P=0,01; r= 0,54) e do peso corporal das éguas com gordura na base da cauda dos potros ao nascimento (P=0,03; r=0,49), além de forte associação entre gordura na base da cauda das éguas obesas com essa medida nos seus potros aos quatro meses (P=0,01; r=0,71). Essa diferença entre os grupos de potros quanto à adiposidade sugere que filhos de éguas obesas são mais propensos a acumular mais gordura já nos primeiros meses de vida.