Seasonal variation in toxicity of citral against Fasciola larva

Objective:To test whether the larvicidal activity of citral against Fasciola varies by season. Methods:Mortality of Fasciola larva in different month of year (2011-2012) in in vitro and in vivo condition were observed at 2 h, 4 h, 6 h and 8 h exposure of citral. Results:In vitro toxicity of citral against redia was highest in between the June to August (8 h LC50: 2.58-2.62 mg/L), whereas against cercaria 8 h LC50 was in between 3.44-2.62 mg/L. Highest in vivo toxicity against redia was noted in between June to August (8h LC50: 4.20-5.09 mg/L). The lowest toxicity was observed from November to April. The highest temperature, free carbon dioxide, and lowest pH, dissolved oxygen were observed from June to August. Conclusions:The present study conclusively shows that varying a biotic factor can significantly alter the in vitro and in vivo toxicity of citral against sporocyst redia and cercaria larva.

Fasciolosis Control: Phytotherapy of Host Snail Lymnaea acuminata by Allicin to Kill Fasciola gigantica Larvae.

Aims: Fasciolosis is a widely distributed disease affecting the lives of herbivorous animals and human. The causative agents are Fasciola hepatica and F. gigantica. Snail Lymnaea acuminata is the intermediate host of Fasciola species. Sporocyst, redia and cercaria are the larval stages found in the snail body. Methodology: The destruction of these larvae in intermediate host is one of the important methods to abolish the incidences of fasciolosis without, killing the snail. Mortality of larvae in in vitro and in vivo condition was observed at 2h, 4h, 6h and 8h, exposure of allicin an active component of Allium sativum. Results: Abiotic factors alter the toxicity of allicin against F. gigantica larvae in different months of year 2011-2012. Highest in vitro toxicity of allicin against redia larva was noted in July (8h LC50 0.001 mg/ml), where as in case of cercaria larva it was in month of June (8h LC50 0.005 mg/ml). Highest toxicity in in vivo treatments against redia and cercaria larvae was observed in February (8h LC50 0.013mg/L and 0.010 mg/L, respectively). The highest temperature, free carbon dioxide, lowest pH and dissolved oxygen were noted in the months of June to August. Conclusion: In vitro and in vivo treatment of allicin against Fasciola larvae is one of the new approaches to control the fasciolosis, without killing the host snail.

In vitro PHYTOTHERAPY OF VECTOR SNAILS BY BINARY COMBINATIONS OF LARVICIDAL ACTIVE COMPONENTS IN EFFECTIVE CONTROL OF FASCIOLIASIS / Fitoterapia in vitro de caramujos vetores por combinações binárias de componentes ativos larvicidas como controle efetivo de fasciolíase

SUMMARY A food-borne trematode infection fascioliasis is one among common public health problems worldwide. It caused a great economic loss for the human race. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. The life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria inside of the snail Lymnaea acuminata. In vitro toxicity of different binary combinations (1:1 ratio) of plant-derived larvicidal active components such as citral, ferulic acid, umbelliferone, azadirachtin and allicin against Fasciola redia and cercaria were tested. The mortality of larvae was observed at 2h, 4h, 6h and 8h of treatment. In in vitro condition azadirachtin + allicin (1:1 ratio) was highly toxic against redia and cercaria (8h LC50 0.006 and 0.005 mg/L). Toxicity of citral + ferulic acid was lowest against redia and cercaria larvae. .

RESUMO A infecção alimentar pelo trematóide da fasciolíase é uma dentre os mais comuns problemas de saúde pública mundiais, causando grande prejuízo econômico para a humanidade. Controle da população de caramujos abaixo de determinado nível é um dos métodos no campo mais importantes para a redução da incidência da fasciolíase. O ciclo de vida do parasita pode ser interrompido pela morte do caramujo ou da larva redia e cercária da Fasciola dentro da Lymnaea acuminata. Foi testada a toxicidade in vitro das diferentes combinações binárias (relação 1:1) entre os vários componentes larvicidas ativos da planta tais como citral, ácido ferúlico, umbeliferone, azadiractina, e alicina contra a Fasciola redia e a cercária. A mortalidade das larvas foi observada após duas, quatro, seis e oito horas de tratamento. A condição in vitro azadiractina + alicina (relação 1:1) foi altamente tóxica contra redia e cercária (8h LC50 0,006 e 0,005 mg/L). Toxicidade do citral + ácido ferúlico foi a mais baixa contra redia e larvas de cercária. .