Evaluation of techniques for recovery of Angiostrongylus vasorum from Achatina fulica, a potential intermediate host

Mollusks are intermediate hosts of Angiostrongylus vasorum, which is a parasite with zoonotic potential for which canids are the definitive host. In this study, 180 specimens of Achatina fulica that had been experimentally infected with 1,000 L1 of A. vasorum were finely chopped to evaluate four tissue digestion techniques: 1% potassium hydroxide (group I); 3% hydrochloric acid (group II); 1% hydrochloric acid and pepsin (group III) with procedures at 37 ºC in a double boiler; and Baermann at 42 °C (group IV). On the first, eighth and thirtieth days after infection, L1, L2 and L3 were obtained, and 240 L3 recovered from group III were offered to a dog. The results were the following: group I: 59% L1, 7% L2, 13% L3; group II: 31% L1, 13% L2, 27% L3; group III: 23% L1, 22% L2, 30% L3; and group IV: 0.3% L1, 0.02% L2, 5% L3. Live larvae wereobserved in group III: 15.5% L1, 8.22% L3; group II: 9.8% L3; and group IV: 100% L1, L2 and L3. Larvae were detected 56 days after the dog became infected. All larvae stages of A. vasorum were recovered and identified through the techniques evaluated, thus confirming the potential of A. fulica as an intermediate host of the nematode

Soil contaminatoon in public squares in belo hoizonte, minas gerais, by caninee parasites in different developmentalsstages / Contaminacao do solo em pracas de Belo Horizonte, MG, por estadios evolutivos de parasitos de caes

SUMMARY To evaluate soil contamination by parasites in different developmental stages in public squares used as recreation and leisure areas for children in Belo Horizonte (MG, Brazil), 210 soil samples and 141 canine fecal samples were collected from 42 squares in the city. These samples were analyzed by the Caldwell and Caldwell technique and the Hoffman, Pons, and Janer technique. Of the samples analyzed, 89 (42.4%) soil samples and 104 (73.5%) fecal samples were contaminated with Ancylostoma sp., Toxocara sp., Trichuris sp., or Dipylidium sp. eggs; Giardia sp. cysts; or Isospora sp. oocysts. The commonest parasite was Ancylostoma sp., found in 85% soil and 99% fecal samples, followed by Toxocara sp., found in 43.7% soil and 30.7% fecal samples. .

RESUMO Visando avaliar a contaminação do solo por estágios evolutivos de parasitos em praças públicas utilizadas como áreas de lazer e recreação infantil em Belo Horizonte (MG, Brasil) foram coletadas 210 amostras de solo e 141 amostras de fezes de cães em 42 praças do município. Estas amostras foram analisadas pelas técnicas de Caldwell & Caldwell, Hoffmann, Pons, Janer. Do total das amostras analisadas, 89 (42,4%) amostras de solo e 104 (73,5%) amostras de fezes estavam contaminadas com ovos de Ancylostoma sp., Toxocara sp., Trichuris sp. e Dipylidium sp.; cistos de Giardia sp; oocistos de Isospora sp., sendo o parasito mais freqüente Ancylostoma sp. com 85% no solo e 99% nas fezes, seguido por 43,7% no solo e 30,7% nas fezes de Toxocara sp. .

Optimization of protease production by the fungus Monacrosporium thaumasium and its action against Angiostrongylus vasorum larvae / Otimização da produção de protease pelo fungo Monacrosporium thaumasium e sua ação contra larvas de Angiostrongylus vasorum

The objectives of this study were to optimize protease production from the nematophagous fungus Monacrosporium thaumasium (NF34a) and evaluate its larvicidal activity and biological stability. An isolate of the nematophagous fungus Monacrosporium thaumasium (NF34a) was used to produce the enzyme. The Plackett-Burman design was used in order to scan which components of the culture medium could have a significant influence on protease production by the fungus NF34a. An in vitro assay was also performed to evaluate the larvicidal activity of NF34a. It was observed that only one component of the culture medium (yeast extract), at the levels studied, had any significant effect (p < 0.05) on protease production. There was a reduction (p < 0.01) in the mean number of larvae recovered from the treated groups, compared with the control groups. The results confirm previous reports on the efficiency of nematophagous fungi for controlling nematode larvae that are potentially zoonotic. Thus, given the importance of biological control, we suggest that further studies should be conducted on the protease produced by the fungus Monacrosporium thaumasium.

O objetivo deste trabalho foi otimizar a produção de proteases do fungo nematófago Monacrosporium thaumasium (NF34a), avaliar sua atividade larvicida e sua estabilidade biológica. Foi utilizado um isolado do fungo nematófago Monacrosporium thaumasium (NF34a) para a produção de enzima. O delineamento Plackett-Burman foi utilizado com o objetivo de se escanear quais componentes do meio de cultura, poderiam ter influência significava na produção de protease pelo fungo NF34a. Foi realizado um ensaio in vitro para avaliar a atividade larvicida de NF34a. Observou-se que apenas um dos componentes do meio de cultura (extrato de levedura), nos níveis avaliados, apresentou um efeito significativo (p < 0,05) sobre a produção de protease. Houve redução (p < 0,01) entre as médias de larvas recuperadas dos grupos tratados em relação às dos grupos controle. Os resultados confirmam trabalhos anteriores da eficiência de fungos nematófagos no controle de larvas de nematóides potencialmente zoonóticos. Assim, devido a importância do controle biológico, os autores sugerem estudos mais aprofundados sobre a protease produzida pelo fungo Monacrosporium thaumasium.

In vitro predatory activity of conidia of fungal isolates of the Duddingtonia flagrans on Angiostrongylus vasorum first-stage larvae

INTRODUCTION:Angiostrongylus vasorum is a nematode that parasitizes molluscs, dogs, and even man. METHODS:The objective was to evaluate the predatory activity of the conidia of two fungal isolates of Duddingtonia flagrans (AC001 and CG722) on first-stage larvae (L1) of A. vasorum in laboratory conditions. RESULTS: At the end of the experiment, there were significant reductions (p<0.01) of 74.5% and 63.2%, on average, in the A. vasorum (L1) recovered in the AC001 and CG722 treatment conditions, respectively. CONCLUSIONS: The two isolates of fungi were efficient in the capture and destruction of A. vasorum (L1).

Atividade larvicida do extrato bruto enzimático do fungo Duddingtonia flagras sobre larvas de primeiro estádio de Angiostrongylus vasorum / Larvicidal activity of a crude enzyme extract of the fungus Duddingtonia flagrans on first-stage larvae of Angiostrongylus vasorum

INTRODUÇÃO: Angiostrongylus vasorum é um nematóide que parasita cães domésticos e eventualmente o homem. MÉTODOS: O objetivo deste trabalho foi observar a atividade predatória in vitro do extrato bruto enzimático do fungo Duddingtonia flagrans sobre larvas de primeiro estádio A. vasorum em condições laboratoriais no meio ágar-água 2 por cento. RESULTADOS: Ao final do experimento, os percentuais de redução das L1 de A. vasorum observados foram de: 53,5 por cento (24h) e 71,3 por cento (48h) CONCLUSÕES: O extrato bruto enzimático do fungo D. flagrans destruiu in vitro as L1, podendo ser utilizado como controle biológico desse nematóide.

INTRODUCTION: Angiostrongylus vasorum is a nematode parasite of domestic dogs and potentially of humans. METHODS: This study aimed to observe the predatory activity in vitro of a crude enzyme extract of the fungus Duddingtonia flagrans on first-stage larvae of A. vasorum in laboratory conditions on 2 percent water-agar. RESULTS: At the end of the experiment, the percentage reductions observed for A. vasorum L1 were 53.5 percent (24h) and 71.3 percent (48h). CONCLUSIONS: Crude enzyme extract of the fungus D. flagrans destroyed the L1 in vitro and can be used as a biological control for this nematode.