title: Lethal dose and clinical signs of Aeromonas hydrophila in Arapaima gigas (Arapaimidae), the giant fish from Amazon.
abstract: Aeromonas hydrophila is causing substantial economic losses in world aquaculture. This study determined the tolerance limit (LD50-96h) of A. hydrophila in Arapaima gigas, and also investigated the clinical signs after intradermal inoculation. Arapaima gigas fingerlings were inoculated intraperitoneally with 0 (control), 1.0×10(5), 1.0×10(6), 1.0×10(7), 1.0×10(9) and 1.0×10(10)CFU/mL of A. hydrophila for the determination of LD50-96h, which was 1.8×10(8)CFU/mL. In another trial with intradermal inoculation of 1.8×10(8)CFU/mL A. hydrophila, there was a 91.6% of mortality between 8 and 23h, and several clinical signs were found. As follows: depigmentation in the tegument, lesions in the tail and fins, loss of balance, reduction of respiratory movements, hemorrhagic foci, necrotic hemorrhages in the kidney, liver and swim bladder, splenomegaly, ascites in the abdominal cavity and hyperemia, enlargement of the gall bladder, among other clinical signs observed. The results showed that A. gigas has a relative tolerance to A. hydrophila when compared to other Neotropical fish species.
authors.affiliation: Programa de Pós-graduação em Biodiversidade Tropical, Universidade Federal do Amapá, Macapá (UNIFAP), AP, Brazil.
authors.forename: Marcia K R
authors.initials: MK
authors.lastname: Dias
authors.affiliation: Laboratório de Microbiologia, Universidade Federal do Amapá (UNIFAP), Macapá, AP, Brazil, Brazil.
authors.forename: Luciana S
authors.initials: LS
authors.lastname: Sampaio
authors.affiliation: Laboratório de Microbiologia, Universidade Federal do Amapá (UNIFAP), Macapá, AP, Brazil, Brazil.
authors.forename: Aldo A
authors.initials: AA
authors.lastname: Proietti-Junior
authors.affiliation: Programa de Pós-graduação em Biodiversidade Tropical, Universidade Federal do Amapá, Macapá (UNIFAP), AP, Brazil; Laboratório de Sanidade de Organismos Aquáticos, Embrapa Amapá, Macapá, AP, Brazil.
authors.forename: Eliane T O
authors.initials: ET
authors.lastname: Yoshioka
authors.affiliation: Laboratório de Enterobactérias, FIOCRUZ, Rio de Janeiro, RJ, Brazil.
authors.forename: Dália P
authors.initials: DP
authors.lastname: Rodrigues
authors.affiliation: Programa de Pós-graduação em Biotecnologia e Biodiversidade, Universidade Federal do Acre (UFAC), AC, Brazil.
authors.forename: Anselmo F R
authors.initials: AF
authors.lastname: Rodriguez
authors.affiliation: Programa de Pós-graduação em Biotecnologia e Biodiversidade, Universidade Federal do Acre (UFAC), AC, Brazil.
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Ribeiro
authors.affiliation: Programa de Pós-graduação em Biotecnologia e Biodiversidade, Universidade Federal do Acre (UFAC), AC, Brazil.
authors.forename: Fernando S E D V
authors.initials: FS
authors.lastname: Faria
authors.affiliation: Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.
authors.forename: Rodrigo O A
authors.initials: RO
authors.lastname: Ozório
authors.affiliation: Programa de Pós-graduação em Biodiversidade Tropical, Universidade Federal do Amapá, Macapá (UNIFAP), AP, Brazil; Laboratório de Sanidade de Organismos Aquáticos, Embrapa Amapá, Macapá, AP, Brazil. Electronic address: marcos.tavares@embrapa.br.
authors.forename: Marcos
authors.initials: M
authors.lastname: Tavares-Dias
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology*; D000818:Animals; D005393:Fish Diseases / Q000382:microbiology* / Q000473:pathology*; D005399:Fishes; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D007928:Lethal Dose 50; D045483:Rivers; D014329:Tropical Climate
keywords: Aeromonas hydrophila; Bacteria; Infection; Pirarucu; Tolerance limit