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Previous issue date: 2008-02-19 / The snail, Achatina fulica (Giant African snail), is registered in almost all Brazilian territory,
and may act as an intermediate host of parasites of the man. This study aimed to describe the
morphology of the nematode larvae found in A. fulica, through light (LM) and scanning
electron microscopy (SEM), and to relate the prevalence of infection to the collection places
of the snails and to the antropic activity. Sixty snails were collected from April/2006 to
April/2007, in the Mesquita City, RJ, transferred to laboratory, kept in terraria, measured and
dissected to verify the infection, distribution of the cysts in tissues of the snails. The cysts
were collected and the larvae were separated. The material thus obtained was used to LM and
SEM. The occurrence of A. fulica in the less conserved area was greater than that in the more
conserved area. However, there was not a significant relation between the intensity of
infection and the collection places and the antropic activity. Fourteen snails (23%) were
infected and the biggest number of cysts/snail verified was 130 and the minor was 1, in snails
that with 106 and 55mm of shell length, respectively. A strong correlation was observed
between the size of the snail and the number of cysts and there was a greater concentration of
these in the pallial cavity, 87%. Of this total, 49% were in the area more vascularized and
38% in the less vascularized area of this cavity. The cysts presented spherical shape, light
pink colored and measured 0.97-1.57mm in diameter and with an unique larva involved by an
amorphous material. Two hundred twenty two encysted larvae were recovered, 30 larvae were
used to the morphological studies. The length of the larvae varied of 2.57-5.8mm, being
classified in: small - until 3.5mm; medium - of 3.53-4.5mm and great - above of 4.52mm. The
average length of the larvae in the three groups was of 2.85; 3.87 and 5.23mm, respectively,
and the total average of 4.2mm. The larvae presented white cuticle, shining, transversally
striated and the lateral line extending to the posterior extremity of the body. In the anterior
end, it is observed mouth provided with three lips, with amphids and papillae, followed by a
muscular oesophagus with average length of 0.61mm, ending in an esophagus bulb. The
nervous ring it was observed in the medium third of the oesophagus and the intestine ends in
an opening located next to the posterior end. The tail had a length varying of 0.15-0.42mm, is
located after this opening may present two types of endings: abrupt or that it sharpens
gradually. The difference in the ending of the tail may suggest sexual dimorphism, although
not to have been observed reproductive structures. The identification to the specific level was
not possible, this pointed to the necessity of continuation of this study. The expressive
population density of A.fulica observed in the conserved area less it confirms the influence of the antropic action on the dispersion of this snail. / O molusco Achatina fulica (Caramujo gigante africano) ? registrado em quase todo territ?rio
nacional, havendo a possibilidade de atuar como hospedeiro de parasitos do homem. Este
estudo objetivou descrever a morfologia dos est?gios larvais de nemat?ides encontrados em A.
fulica, atrav?s de microscopia de luz e eletr?nica de varredura, e relacionar a preval?ncia de
infec??o aos locais de coleta dos moluscos e ? atividade antr?pica. Sessenta moluscos foram
coletados de abril de 2006 a abril de 2007, no munic?pio de Mesquita, RJ, transferidos para o
laborat?rio, mantidos em terr?rios, medidos e dissecados para verifica??o da infec??o,
distribui??o dos cistos pelos tecidos do molusco, coleta dos cistos e obten??o das larvas.
Procedeu-se a fixa??o e o processamento para microscopia de luz e eletr?nica de varredura. A
ocorr?ncia de A. fulica na ?rea menos conservada foi maior que na ?rea mais conservada.
Por?m n?o houve uma rela??o significativa entre a intensidade de infec??o aos locais de
coleta e ? atividade antr?pica. Quatorze moluscos (23%) estavam infectados e o maior
n?mero de cistos verificado por molusco foi de 130 e o menor de 01, em moluscos que
apresentavam 106 e 55mm de comprimento de concha, respectivamente. Foi observada uma
forte correla??o entre o tamanho do molusco e o n?mero de cistos encontrados e maior
concentra??o destes na cavidade paleal, 87%. Desse total, 49% estavam na ?rea mais
vascularizada e 38% na menos vascularizada da cavidade. Os cistos apresentavam formato
esf?rico, colora??o rosada e mediam de 0,97 a 1,57mm de di?metro e na maioria das vezes
com uma ?nica larva que se encontrava envolvida por um material amorfo. Foram
recuperadas 222 larvas encistadas. Destas, 30 foram utilizadas no estudo morfol?gico. O
comprimento das larvas variou de 2,57 a 5,8mm, sendo classificados em: pequeno at?
3,5mm; m?dio de 3,53 a 4,5mm e grande - acima de 4,52mm. O comprimento m?dio das
larvas nos tr?s grupos foi de 2,85; 3,87 e 5,23mm, respectivamente, e a m?dia total de 4,2mm.
As larvas apresentavam cut?cula branca, brilhante e estriada no sentido transversal e linha
lateral at? a extremidade posterior do corpo. Na extremidade anterior, observa-se a boca
provida de tr?s l?bios, com anf?dios e papilas, seguida por um es?fago musculoso com
comprimento m?dio de 0,61mm, terminando em um bulbo esofagiano. O anel nervoso foi
observado no ter?o m?dio do es?fago e o intestino termina em uma abertura localizada pr?ximo ? extremidade posterior. A cauda, com comprimento variando de 0,15 a 0,42mm, se
forma a partir desta abertura e apresenta dois tipos de termina??es: abrupta ou que afina
gradativamente. A diferen?a na termina??o da cauda pode sugerir dimorfismo sexual, apesar
de n?o terem sido observados prim?rdios de ?rg?os reprodutores. Com os resultados obtidos
n?o foi poss?vel a identifica??o ao n?vel espec?fico, havendo dessa forma a necessidade de
continua??o deste estudo. A densidade populacional expressiva de A. fulica observada na ?rea
menos conservada confirma a influ?ncia da a??o antr?pica sobre a dispers?o deste molusco.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:tede/758 |
| Date | 19 February 2008 |
| Creators | Acu?a, Daniela de Oliveira Franco |
| Contributors | Silva, Jairo Pinheiro da, Brandolini, Solange Viana Paschoal Blanco |
| Publisher | Universidade Federal Rural do Rio de Janeiro, Curso de P?s-Gradua??o em Ci?ncias Veterin?rias, UFRRJ, Brasil, Parasitologia Veterin?ria |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFRRJ, instname:Universidade Federal Rural do Rio de Janeiro, instacron:UFRRJ |
| Rights | info:eu-repo/semantics/openAccess |
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