Detection of Brucella spp. in free-living Amazon river dolphin (Inia geoffrensis) in Mamiraua reserve, in Tefé, Amazonas, Brazil

Author(s)

Mayra Pereira Rocca

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2014-07-03

Examining board members

Lara Borges Keid; Adriana Cortez; Leonardo José Richtzenhain

• Advisor: Lara Borges Keid

Abstract

There is a growing concern among several countries and international institutions of animal health and conservation regarding the surveillance of infectious diseases in wildlife populations, because these infections may cause impact on the dynamics and conservation of wildlife species, as well as on the health of livestock and public health. Brucellosis has been reported in several species of marine mammals in various research centers worldwide. However, there is no data about the occurrence of brucellosis in aquatic mammals in Brazil. Brucellosis in cetacean is caused by Brucella ceti and has been associated to reproductive problems, meningoencephalitis and lymphoid tissues infections. The objective of this study was to investigate the occurrence of Brucella spp. infection in free living amazon river dolphin (Inia geoffrensis), from Mamirauá Sustainable Development Reserve, in Tefé municipality, Amazonas State, Brazil. Samples were collected from free-living animals from both sexes and different ages during two expeditions, in 2010 and 2011. Samples of serum, whole blood and milk as well as genital, anal, nasal, oral and cutaneous lesions swabs were collected. One hundred and sixty one animals were samples. Serodiagnosis was performed using the acidified buffered antigen test (ABAT), the 2-mercaptoethanol (2ME) test and the fluorescent polarization assay (FPA). Milk and swabs samples were submitted to microbiological culture and polymerase chain reaction (PCR) to the direct diagnosis of Brucella spp. Bacterial colonies showing morphologies compatible with Brucella spp. were tested by a PCR using specific primers directed to the 16S-23S interpace region of the ribosomal DNA of Brucella (ITS-PCR). Samples with positive results by ITS-PCR were amplified using primers specific to the gene recA (PCR-recA), and the amplicon was sequenced. ITSPCR was also used to diagnosis of Brucella spp. infections directly in samples of blood, milk and swabs which were characterized as the bacterial colonies. All 67 serum samples were negative in the three serological tests used. Eleven of the 128 (8.59%) animals showed positive results by ITS-PCR in at least one biological sample. Of the 369 samples tested by microbiological culture, two had positive results in ITS-PCR. Accroding to the characterization of recA gene, one of them was identified as Ochrobactrum intermedium and the other sample could not be characterized because it was not isolated in pure culture. Of the 118 whole blood samples, six (7.08%) were positive by ITS-PCR. Five of the 248 (17.24%) milk samples and one of the 248 (0.4%) swab samples were positive by ITS-PCR. Of the 12 psoitive samples by ITS-PCR, only two were amplified by the recA-PCR and sequenced. According to the phylogenetic analysis, one sample clustered with Cellulomonas fimi, Cellulomonas flavigena e Cellvibrio gilvus group showing major similarity with C. fimi. The other sample clustered with the bacteria Propionicimonas paludicola, Micropruina glycogenica, Naumannella halotolerans, being more similar to Propionibacterium propionicum. An Ochrobactrum intermedium strain was isolated from a dolphin, however, the sanitary importance of the detection could not be determined. (AU)

• FAPESP's process: 12/18065-9 - Detection of Brucella spp. and Morbillivirus infection in free-living Amazon river dolphin (Inia geoffrensis) spp. in Mamiraua Reserve, in Tefé, Amazonas, Brazil
• Grantee: Mayra Pereira Rocca
• Support Opportunities: Scholarships in Brazil - Master