Comparative studies of codon usage profile of Anisakis simplex (Nematoda) and Carassius gibelio (Prussian carp)

Aim: The aim of the present study was to understand the molecular relationship between nematode (parasite) and fish (host) through codon usage bias (CUB) analysis. Methodology: The Codon usage bias analysis has been performed in fish Carassius gibelio (Prussian carp) and nematode fish parasite Anisakis simplex. The complete coding sequences (CDS) of C. gibelio (Prussian carp) and A. simplex (Nematode) were retrieved from National Center for Biotechnology Information and followed to that we have performed bioinformatics analysis to understand the codon usage pattern between host and parasite. Results: Different CUB indices like Relative synonymous codon usage (RSCU), Effective number of codons (ENC), Codon adaptation index (CAI) and Codon bias index (CBI) revealed a similar pattern in the codon usage in C. gibelio and A. simplex. In addition, inclusive analysis using different plots (ENC, parity, neutrality) had shown the influence of both the evolutionary forces i.e mutational and translational selection on codon usage pattern. This describes the role of evolutionary forces in determining the conserved genome to establish species-specific function-level differences for efficient survival. Interpretation: The present study elucidated the association between Carassiusgibelio (host) and Anisakis simplex (parasite) based on the similar pattern of codon usage bias between both the species.

Nematode Parasites of Rockfish (Sebastes spp.) and Cod (Gadus spp.) from Waters near Kodiak Island Alaska, USA

Distribution and abundance of common parasitic nematodes in marine fishes is not well documented in many geographic regions. Understanding the influence of large-scale environmental changes on infection rates of fish by nematodes requires quantitative assessments of parasite abundance for multiple host species. We collected samples of two species of cod and eight species of rockfish (total of 232 specimens) from waters near Kodiak Island, Alaska, USA during Spring and Summer of 2015, and dissected and recorded all internal nematode parasites. We quantified the prevalence and intensity of nematode parasites in the ten host species, and tested for differences in prevalence among host species. We found three species of nematode: Anisakis simplex, sensu lato (Van Thiel), Pseudoterranova decipiens, sensu lato (Krabbe), and Hysterothylacium sp. (Ward and Magath). Eighty-two percent of the examined fish were infected with at least one parasitic nematode. The overall prevalence of P. decipiens, A. simplex, and Hysterothylacium sp. was 56%, 62%, and 2%, respectively. Anisakis simplex and P. decipiens were abundant and present in all ten species of host fish examined, whereas Hysterothylacium sp. was rare and found in only five of the host fish species. Prevalence and mean intensity of P. decipiens and A. simplex varied across the ten host species, and the number of parasites varied substantially among individual hosts within host species. The mean intensity of P. terranova and A. simplex in our study was substantially higher than the mean intensity for these same species from multiple other locations in a recent meta-analysis. This study provides a baseline of nematode parasite abundance in long-lived fish in waters near Kodiak Island, AK, and fills an important gap in our quantitative understanding of patterns of occurrence and abundance of these common and widespread parasites of marine fish.

Hybrid Genotype of Anisakis simplex (s.s.) and A. pegreffii Identified in Third- and Fourth-Stage Larvae from Sympatric and Allopatric Spanish Marine Waters

The sibling species Anisakis simplex (s.s.) and Anisakis pegreffii are parasites of marine mammals and fish worldwide and the main causative agents of human anisakiasis. In sympatric areas, a hybrid genotype between the two species has been identified, mainly in third-stage larvae, but rarely in fourth-stage and adult forms. The aim of this study was to confirm the presence of hybrid genotypes in larvae parasitizing fish caught in sympatric and allopatric Spanish marine waters, the North-East Atlantic and West Mediterranean, respectively, and to study possible differences in the growth behaviour between genotypes. Of the 254 molecularly analysed larvae, 18 were identified as hybrids by PCR-RFLP analysis of the rDNA ITS region, 11 of which were subsequently confirmed by EF1 α-1 nDNA gene sequencing. These results therefore indicate an overestimation of hybrid genotypes when identification is based only on the ITS region. We also report the detection of a hybrid specimen in a host from the West Mediterranean, considered an allopatric zone. Additionally, fourth-stage larvae with a hybrid genotype were obtained in vitro for the first time, and no differences were observed in their growth behaviour compared to larvae with A. simplex (s.s.) and A. pegreffii genotypes.

First Report Of IgE Sensitization To Anisakis Simplex In a Healthy Population in Colombia

The anisakiasis is little known in Colombia and rarely diagnosed. However, reports of fish parasitized by anisakid larvae in South America are increasing. The objective was determine the prevalence of sensitization to Anisakis simplex in a healthy population in Colombia. Cross-sectional survey of 150 volunteers from Universidad del Valle’s community, Cali, Colombia. Past medical history, including eating habits associated with fish consumption was assessed. Prevalence of IgE antibodies was determined by the ELISA- Trisakis 170 kit for the recombinant allergens Ani s 1 and Ani s 7. Two sera (1.3%) of blood tested were positive to the Ani s 7 antigen, while for Ani s 1 all sera were negative. This research is the first exploratory study on Anisakis prevalence conducted in Colombia, the results do not indicate a major problem. Nevertheless, more epidemiological studies are needed.

NEMÁTODOS ANISAKIDOS LARVARIOS DEL LENGUADO PARALICHTHYS ISOSCELES JORDAN, 1890 (PISCES: TELEOSTEI) EN BRASIL

Desde Octubre hasta Marzo, 2006, 60 ejemplares de Paralichthys isosceles fueron colectados en el litoral del Estado do Rio de Janeiro, Brasil, con el objetivo de hacer un inventario de nematodos anisákidos considerando su importancia en las zoonosis. Cinco especies larvales son representadas con un total de 1.900 parásitos, siendo 1.850 muestras de Hysterothylacium sp., 71 de Raphidascaris sp., cuatro of Terranova sp., tres de Anisakis simplex y dos de Contracaecum sp. Los parásitos fueron encontrados en la cavidad abdominal, mesenterio, intestino, hígado, mucosa estomacal, estomago, ovarios, musculatura abdominal, y en las serosas del corazón, bazo, estomago, riñones y ovarios. Larvas de Hysterothylacium sp. aparecieron con una prevalencia (P) de 100%, intensidad media (MI) de 30,3, amplitud de intensidad (RI) de 1 a 596 y abundancia media (MA) de 32, Raphidascaris sp. con P = 39%, MI = 3,2, RI = 1 a 29 y MA= 1,2, Anisakis simplex con P = 5%, Intensidad (I) = 1 y MA= 0,06, Terranova sp. con P = 5%, (I) = 1 y MA= 0,05, Contracaecum sp. con P = 3,0%, I =1 y MA = 0,03. Este es el primero reporte de índices parasitarios y sitios de infección de larvas de A. simplex, Contracaecum sp. Terranova sp., Hysterothylacium sp. y Raphidascaris sp. en Paralichthys isosceles que es un nuevo registro de hospedero para larvas de Anisakis simplex y Hysterothylacium sp.

CATASTRO DE LA FAUNA ENDOPARASITARIA DE LA POTA DOSIDICUS GIGAS (CEPHALOPODA) EN EL NORTE DEL PERÚ

La “pota” o “calamar gigante” Dosidicus gigas (Orbigny 1835) es uno de los cefalópodos de mayor tamaño y uno de los más abundantes en los ambientes pelágicos-oceánicos. Esta especie migratoria y endémica del Pacífico sureste es uno de los recursos hidrobiológicos de mayor importancia económica en el Perú. Durante el 2008 y 2009 se muestrearon 42 potas de longitud dorsal del manto entre 53, 5 cm y 93 cm, procedentes de Sechura (n= 22, 52,3%), Paita (n= 16, 38,1%), Chimbote (n= 2, 4,7%) y Bayovar (n= 2, 4,7%). Se registraron un total de cinco helmintos larvarios en el manto y fibras musculares con los siguientes descriptores de ecología parasitaria: principal Tentacularia coryphaenae Bosc, 1797 (Prevalencia = 90,4%; Abundancia media = 3,97); secundario Anisakis physeteris Baylis, 1923 (Prevalencia = 19,1%; Abundancia media = 0,33); raro Anisakis simplex (Dujardin, 1845) (Prevalencia = 4,7%; Abundancia media = 0,07); raro Porrocaecum sp. (Prevalencia = 2,3%; Abundancia media = 0,02); y raro Contracaecum sp. (Prevalencia = 2,3%; Abundancia media = 0,02). Se observó ausencia de relación lineal con la LDM del hospedero, y la prevalencia y abundancia media de T. coryphaenaey del parasitismo global. La prevalencia de A. physeteris no presentó una relación lineal con la talla del hospedero. En cambio únicamente, la abundancia media de A. physeteris tuvo una relación lineal directa con la LDM de D. gigas. Las dos especies de Anisakis emplean a la pota como hospedero paraténico (transporte ciclogénico) y pueden producir anisakiosis (o anisakiasis), una parasitosis zoonótica humana del tracto digestivo.