Revista Brasileira de Parasitologia Veterinária (Dec 2009)

Possibilidade de ocorrência de resistência adquirida em cães sucessivamente infestados por ninfas de Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) Possible acquired resistance of dogs successively infested by Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) nymphs

  • Carolina Maria Vianna de Freitas,
  • Romário Cerqueira Leite,
  • Eduardo Bastianetto,
  • Arildo Pinto da Cunha,
  • Ana Cristina Passos de Paiva Belo

DOI
https://doi.org/10.4322/rbpv.018e1007
Journal volume & issue
Vol. 18
pp. 40 – 42

Abstract

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O presente trabalho teve por objetivo avaliar a ocorrência de resistência imune em cães, frente a infestações sucessivas por ninfas de Amblyomma cajennense. Para tanto, cinco animais foram submetidos a quatro infestações consecutivas por ninfas de A. cajennense em intervalos de quatorze dias. Foram aplicadas 50 ninfas em cada animal por infestação e os dados referentes aos períodos parasitários e não parasitários, foram registrados. As taxas médias de recuperação de ninfas ingurgitadas, verificadas nas sucessivas infestações foram de 52,0, 29,2, 9,6 e 12,8%, sendo observada uma redução significativa (p The present study aimed to evaluate the occurrence of immune resistance in dogs successively infested with Amblyomma cajennense nymphs. Five animals were submitted to four consecutive infestations with A. cajennense nymphs, at fourteen-day intervals. For each infestation, 50 nymphs were used per animal and data on the parasitic and non-parasitic periods were recorded. The average recovering rate of engorged nymphs in the successive infestations were 52.0, 29.2, 9.6 and 12.8%, respectively, with a significant reduction (p < 0.05) of this parameter from the second infestation onwards. The modal drop-off day of engorged nymphs was Day 4 of parasitism in all infestations. The average mortality rates of nymphs seen on the first, second, third and fourth infestations were 3.6, 3.2, 2.0 and 2.8%, respectively, with no significant differences among them (p < 0.05). In addition, no significant differences were seen among the ecdysis rates for specimens recovered from successive parasitic challenges. The study results suggest that the acquired resistance of infested dogs had a negative effect on recovery rate of A. cajennense nymphs; however, it did not affect the other biological parameters evaluated.

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