Nematode infection in fish from Cartagena Bay, North of Colombia

De novo assembly and characterization of the liver transcriptome of Mugil incilis (lisa) using next generation sequencing

Mugil incilis (lisa) is an important commercial fish species in many countries, living along the coasts of the western Atlantic Ocean. It has been used as a model organism for environmental monitoring and ecotoxicological investigations. Nevertheless, available genomic and transcriptomic information for this organism is extremely deficient. The aim of this study was to characterize M. incilis hepatic transcriptome using Illumina paired-end sequencing. A total of 32,082,124 RNA-Seq read pairs were generated utilizing the HiSeq platform and subsequently cleaned and assembled into 93,912 contigs (N50 = 2,019 bp). The analysis of species distribution revealed that M. incilis contigs had the highest number of hits to Stegastes partitus (13.4%). Using a sequence similarity search against the public databases GO and KEGG, a total of 7,301 and 16,967 contigs were annotated, respectively. KEGG database showed genes related to environmental information, metabolism and organismal system pathways were highly annotated. Complete or partial coding DNA sequences for several candidate genes associated with stress responses/detoxification of xenobiotics, as well as housekeeping genes, were employed to design primers that were successfully tested and validated by RT-qPCR. This study presents the first transcriptome resources for Mugil incilis and provides basic information for the development of genomic tools, such as the identification of RNA markers, useful to analyze environmental impacts on this fish Caribbean species.

Anisakidae nematodes isolated from the flathead grey mullet fish (Mugil cephalus) of Buenaventura, Colombia

Anisakiasis is a parasitic infection caused by larval stages of nematodes of the genus Anisakis, Pseudoterranova and Contracaecum, of the Anisakidae family. The lifecycle of these nematodes develops in aquatic organisms and their final hosts are marine mammals. However, humans can act as accidental hosts and become infected with infective stage larvae (L3) by consuming raw or undercooked fish or shellfish carrying the parasite. Of this group of parasites, the genus Anisakis is the most studied: its presence in humans is associated with non-specific gastrointestinal symptoms or allergic responses that can trigger anaphylactic shock. The lack of studies in anisakiasis and Anisakis in Colombia has resulted in this infection being little-known by medical practitioners and therefore potentially underreported. The objective of this study was to identify anisakid nematodes in the flathead grey mullet fish (Mugil cephalus), caught by artisanal fishing methods and commercialized in Buenaventura. Morphological identification was carried out by classical taxonomy complemented by microscopy study using the histochemical technique Hematoxylin-Eosin. Nematodes of the genus Anisakis were found in the host M. cephalus. The Prevalence of Anisakis larvae in flathead grey mullet fish was 33%. The findings confirm the presence of Anisakis sp. in fish for human consumption in the Colombian Pacific region, a justification for further investigation into a possible emerging disease in this country.

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The research confirmed the presence of anisakids in the fish M. cephalus in Colombia.

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First report such anisakids in fish from Colombia's Pacific coast.

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Is confirmed the presence of the genus Anisakis in the country.

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Anisakis spp. is associated with allergic reactions and gastro-allergies in humans.

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The presence the anisakids suggests a possible emerging zoonotic disease in Colombia.