Viabilidade de miracídios de Schistosoma mansoni, obtidos de fezes e de granulomas hepáticos de camundongos experimentalmente infectados com a linhagem BH

Zanotti-Magalhães, Eliana Maria; Paiva, Sônia Minervino de; Magalhães, Luiz Augusto; Carvalho, José Ferreira de

doi:10.1590/s0034-89101988000600002

Cited by 3 publications

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References 10 publications

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“…Certainly a potentially important practical factor for evaluating temperature effects in miracidia is the source of eggs used for experimental studies. Eggs can be obtained from host tissues, sexually mature worms, or from naturally emitted routes and their origins can determine both the duration of egg embryonation and miracidial survival and viability (Weina, 1986; Zanotti-Magalhaes et al 1988; McKindsey and McLaughlin, 1994). The available evidence on temperature and miracidial survival suggests that overall there are significant differences between individuals hatched from eggs removed from adult flukes and eggs passed naturally in the host faeces.…”

Section: Discussionmentioning

confidence: 99%

Thermodynamics of miracidial survival and metabolism

Morley

2012

Parasitology

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Miracidia are short-lived, non-feeding (lecithotrophic) free-living stages of trematodes, whose survival is potentially influenced by temperature. Climate change may result in elevated temperatures affecting trematode transmission. Therefore understanding their thermobiology forms an important step in determining the future dynamics of parasite populations. An empirical relationship exists between the mean expected life span of lecithotrophic larvae and the half life of their population (t(0·5)) and therefore t(0·5) is a good indicator of glycogen utilization. In this study experimental data on the effects of temperature on miracidial survival were compiled from the scientific literature and evaluated in terms of metabolism using Q 10 and Arrhenius activation energy (E* or μ). Temperature poorly influenced survival/metabolism with all miracidia having distinct zone(s) of thermostability. Overall there were few differences in Q(10) and E* values between most species temperature ranges whilst there were only limited strain-specific variations in thermal responses of laboratory-maintained Schistosoma mansoni. Miracidia demonstrated a trend of greater thermal resistance than cercariae. In particular, comparative studies on 4 strains of the same species of miracidia and cercariae showed little correlation in thermal biology between the 2 life-history stages. The importance of these results for trematode transmission under global climate change is discussed.

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Section: Discussionmentioning

confidence: 99%

Thermodynamics of miracidial survival and metabolism

Morley

2012

Parasitology

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Relação entre patogenicidade do Schistosoma mansoni em camundongos e susceptibilidade do molusco vetor. IV - Infecciosidade dos miracidios

1997

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OBJETIVO: Comparar a capacidade de infecção de miracídios das linhagens BH e SJ de S. mansoni, obtidos de camundongos infectados com cercárias oriundas de Biomphalaria glabrata e B. tenagophila, selecionadas geneticamente para a susceptibilidade, com miracídios obtidos de camundongos infectados com larvas procedentes de moluscos não selecionados. MATERIAL E MÉTODO: Progenies de S. mansoni foram obtidas das passagens sucessivas pelos moluscos selecionados, obtendo-se assim gerações de miracídios selecionados. A seleção de B. glabrata e B. tenagophila foi realizada através da autofecundação dos moluscos susceptíveis, frente às respectivas linhagnes BH e SJ do trematódeo. Foram obtidas 5 gerações de moluscos (P a F4). Os testes de infecciosidade dos miracídios foram realizados utilizando-se 10 larvas e a susceptibilidade verificada após 30 dias e durante 3 meses, através da detecção da eliminação de cercárias. RESULTADOS: Evidenciou-se que a susceptibilidade de moluscos selecionados, confrontada com as respectivas linhagens simpátricas, não foi alterada pelo processo de selecão das linhagens do trematódeo, porém miracídios BHF4 foram mais infectantes frente a B. glabrata não selecionada do que miracídios BHP. A seleção de B. glabrata propiciou sua infecção de modo semelhante com miracídios BHP, SJP e BHF3 . Esses moluscos não apresentaram a mesma capacidade de infecção frente a miracídios alopátricos selecionados (SJF4). A passagem sucessiva do S. mansoni SJ em B. tenagophila selecionada ajustou essa linhagem para essa espécie de molusco. B. tenagophila nunca foi susceptível à linhagem BH, mesmo utilizando moluscos e trematódeos selecionados. A susceptibilidade/infecciosidade do binomio B. tenagophila - linhagem SJ só foi alterada pelo processo de seleção do molusco. CONCLUSÕES: Como miracídios BH selecionados infectaram, de forma mais intensa, B. glabrata não selecionada do que miracídios BH não selecionados, conclui-se que a maior patogenicidade do S. mansoni, oriundo de moluscos mais susceptíveis, implica maior capacidade de infecção desses miracídios.

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Biological and morphological characteristics of Schistosoma mansoni from Ribeira Valley, State of São Paulo, Brazil: I - susceptibility of Biomphalaria tenagophila snail to sympatric S. mansoni strain

Figueiredo¹,

Dias²,

Marques³

1992

Rev. Inst. Med. trop. S. Paulo

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In the São Paulo State, Brazil, where the Biomphalaria tenagophila is the intermediate host, the Ribeira Valley is an important endemic schistosomiasis mansoni area. During last eleven years there has been intense control measures focusing on schistosomiasis. The efforts have been concentrated in the municipalities of Pedro de Toledo and Itariri. We determined the susceptibility of B. tenagophila to sympatric strain of S. mansoni, both recently isolated from Itariri field. In 1988, this strain was isolated and maintained in the experimental model: Swiss mice - sympatric B. tenagophila. The second generation of the worm was evaluated. The snail were divided in the three groups of 60 snails each. One group was exposed to 1 miracidium and other to 10. The third group was the control. The mortality and the shedding of cercariae were checked during 78 days. After that, the positive snails were observed until they ceased to shed cercariae. The exposed molluscs showed mortality rates of 23% and 31% and infection indexes were of 8% and 60% to 1 and 10 miracidia respectively. The mortality was of 22% in the control group. The periods of shedding cercariae in the two groups were 82 and 104 days. We can conclude that B. tenagophila is an effective intermediate host to the sympatric strain of S. mansoni sympatric strain

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Viabilidade de miracídios de Schistosoma mansoni, obtidos de fezes e de granulomas hepáticos de camundongos experimentalmente infectados com a linhagem BH

Cited by 3 publications

References 10 publications

Thermodynamics of miracidial survival and metabolism

Thermodynamics of miracidial survival and metabolism

Relação entre patogenicidade do Schistosoma mansoni em camundongos e susceptibilidade do molusco vetor. IV - Infecciosidade dos miracidios

Biological and morphological characteristics of Schistosoma mansoni from Ribeira Valley, State of São Paulo, Brazil: I - susceptibility of Biomphalaria tenagophila snail to sympatric S. mansoni strain

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