Bacteriophages to control Vibrio alginolyticus in live feeds prior to their administration in larviculture.

AIMS: This study aimed to evaluate the efficiency of two phages [VB_VaC_TDDLMA (phage TDD) and VB_VaC_SRILMA (phage SRI)] alone and in a cocktail to control Vibrio alginolyticus in brine shrimp before their administration in larviculture. METHODS AND RESULTS: Phages were isolated from seawater samples and characterized by host spectrum, growth parameters, adsorption rate, genomic analysis, and inactivation efficiency. Both phages belong to the Caudoviricetes class and lack known virulence or antibiotic-resistance genes. They exhibit specificity, infecting only their host, V. alginolyticus CECT 521. Preliminary experiments in a culture medium showed that phage TDD (reduction of 5.8 log CFU ml-1 after 10 h) outperformed phage SRI (reduction of 4.6 log CFU ml-1 after 6 h) and the cocktail TDD/SRI (reduction of 5.2 log CFU ml-1 after 8 h). In artificial marine water experiments with Artemia franciscana, both single phage suspensions and the phage cocktail, effectively inactivated V. alginolyticus in culture water (reduction of 4.3, 2.1, and 1.9 log CFU ml-1 for phages TDD, SRI, and the phage cocktail, respectively, after 12 h) and in A. franciscana (reduction of 51.6%, 87.3%, and 85.3% for phages TDD, SRI, and the phage cocktail, respectively, after 24 h). The two phages and the phage cocktail did not affect A. franciscana natural microbiota or other Vibrio species in the brine shrimp. CONCLUSIONS: The results suggest that phages can safely and effectively control V. alginolyticus in A. franciscana prior to its administration in larviculture.

Detection of rabies virus in cranial cavity lavage of naturally infected bats.

The rabies virus (RABV) has been isolated in several bats species in the world, and among them, hematophagous, frugivorous and insectivorous species. Bats found in Brazil are small, which can lead to situations in which there are limitations in the collection of the central nervous system (CNS) and the amount of material may be insufficient to carry out laboratory diagnostic techniques for rabies. The objective of this work was to evaluate an alternative sample collection for the diagnosis of rabies in bats. A total of 92 bat samples, 82 positives and 10 negatives were selected. The cranial cavity was scraped with the aid of sterile tips and a virus diluent was added to create a suspension. All samples were submitted to Rabies Tissue Culture Infection Test (RTCIT) and reverse transcription polymerase chain reaction (RT-PCR). The diagnostic sensitivity and specificity of the RTCIT and RT-PCR using the cranial cavity lavage were calculated in comparison with the results of the laboratory routine (DFAT and RTCIT) performed with the CNS (considered gold standard). The results of the RTCIT show that the cranial cavity lavage is not an adequate sample for viral isolation, since the diagnostic sensitivity was low (37.8 %) when compared with the tests with the CNS. However, the RT-PCR of the cranial cavity lavage may be a tool to assist in the diagnosis, since it presented a sensitivity of 76.8 %. The results of this study suggest that cranial cavity lavage is an interesting alternative to enable the diagnosis of rabies in bats and increases the possibility of diagnosis contributing to rabies surveillance and control.

Brown booby (Sula leucosgaster) envenomation and death caused by toadfish (Porichthys porosissimus) ingestion in Southeastern Brazil / Envenenamento e morte de atobás-marrons (Sula leucogaster) causados pela ingestão de magangá-liso (Porichthys porosissimus) no sudeste do Brasil

Abstract A case report of six brown booby (Sula leucogaster) envenomation following the ingestion of toadfish (Porichthys porosissimus) specimens in Rio de Janeiro, Southeastern Brazil is discussed herein. Several macro- and microscopic pathological alterations were observed in the examined brown booby specimens, and rapid envenomation (<24 h) is suggested due to the digestion stage of the fish found in their gastrointestinal tracts. This is the first report to mention the death of adult and juvenile brown boobies due to envenomation by the toadfish P. porosissimus. Further studies assessing the role of discarded fish as a driving force of negative effects on seabirds, such as envenomations, for example, along the southeastern coast of Brazil are recommended.

Resumo Um relato de caso sobre o envenenamento de seis indivíduos de atobás-marrons (Sula leucogaster) após a ingestão de espécimes de mangagá-liso (Porichthys porosissimus) no Rio de Janeiro, sudeste do Brasil, é discutido neste estudo. Diversas alterações patológicas macro e microscópicas foram observadas nos espécimes de atobá-marrom examinados, e um envenenamento rápido (<24 h) é sugerido devido ao estágio de digestão dos peixes encontrados em seus tubos digestórios. Este é o primeiro registro que menciona a morte de indivíduos juvenis e adultos de atobás marrons por envenenamento devido a ingestão do magangá-liso P. porosissimus. Novos estudos avaliando o papel dos peixes descartados como uma força motriz dos efeitos negativos sobre as aves marinhas como, por exemplo, envenenamentos, ao longo da costa sudeste do Brasil são recomendados.