Raphidascaris Larvae (Nematoda: Anisakidae) in Marine Fish Mugil cephalus Linn., 1758 from Karachi Coast, Pakistan

Faiza Saleem1, Aly Khan2*, Rafia Rehana Ghazi3, Nasira Khatoon1, Samina Waheed1, Mian Sayed Khan4

1Department of Zoology, University of Karachi, Karachi-75270, Pakistan; 2CDRI, Pakistan Agricultural Research Council, University of Karachi, Karachi-75270, Pakistan; 3VPCI, Southern Zone Agriculture Research Council, University of Karachi, Karachi-75270, Pakistan; 4Department of Zoology, University of Swabi, Khyber Pakhtunkhwa, Pakistan.

Received | April 22, 2022; Accepted | June 16, 2022; Published | June 24, 2022

*Correspondence | Aly Khan, CDRI, Pakistan Agricultural Research Council, University of Karachi, Karachi-75270, Pakistan; Email: aly.khan@hotmail.com

Citation | Saleem, F., Khan, A., Ghazi, R.R., Khatoon, N., Waheed, S., Khan, M.S., 2022. Raphidascaris larvae (Nematoda: Anisakidae) in marine fish Mugil cephalus Linn., 1758 from Karachi coast, Pakistan. Pakistan Journal of Nematology, 40(1): 62-64.

DOI | https://dx.doi.org/10.17582/journal.pjn/2022/40.1.62.64

Keywords | Raphidascaris, 3rd stage larvae, Mugil cephalus, Karachi coast, Pakistan

Copyright: 2022 by the authors. Licensee ResearchersLinks Ltd, England, UK.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

Introduction

Fish diseases due to nematode family Anisakidae are widespread (Buchmann and Mehrdana, 2016). It has an indirect life cycle. Crustaceans along with marine mammals are definitive hosts whereas crustaceans (Euphausiacea) act as intermediate host. These crustaceans may be eaten by fish or cephalopods which are third stage larvae (Santos et al., 2022; Guardone et al., 2016; Daschner et al., 2000). Various types of anisakid larvae belonging to the genus namely Anisakis, Raphidascaris, Contracaecum and Hysterothylacium are found in fish.

In a study to examine nematodes of the fish Mugil cephalus Linn, 1758 from Karachi coast, Sindh, Pakistan. Larvae of the genus Raphidascaris (Railliet and Henry, 1915) were recorded in large numbers. The larvae belonged to the genus Raphidascaris (Railliet and Henry, 1915). This nematode genus belonging to the family Raphidascarididae. Different species of the genus are found in Northern America, Europe and Australia (GBIF Secretariat, 2021).

Materials and Methods

During a period of 6 months from March to August 2000, 30 fish (Mugil cephalus Linn., 1758) were examined for larval nematodes. A total of 5000 larvae were recovered from the tissue of visceral organs more frequently from stomach and liver. Larvae were fixed and stored in 70% alcohol and glycerine in the ratio of 1:1. Diagrams were prepared using a camera Lucida. Measurements are given length by width in millimeters. The specimens are in possession of senior author (F.S).

Phylum: Nematoda

Class: Chromadorea

Order: Rhabditida

Superfamily: Ascaridoidea

Family: Raphidascarididae

Genus: Raphidascaris

Raphidascaris larvae

(Figure 1a-c)

Host: Mugil cephalus Linn, 1758

Location: Small intestine and stomach tissue

Locality: Karachi coast, Pakistan

Number of hosts examined: 12

Number of parasites recovered: 5000 from 4 hosts

Number of specimens studied: 30

Description

Small translucent worms, 30-40 mm long, 0.035-0.0056 wide at the cephalic region, while the width at oesophageal junction is 0.29-0.30. The anterior head is transformed into membranous flap like structure which indicates probably the developing lips, this leads into a well developed oesophagus 1.015 long and 0.04-0.05 at the base, further into simple intestine. The cuticle is thin and does not appear to be striated. An excretory pore is situated at a distance of 0.26-0.28 from the head end, this leads into excretory tube. Nerve ring is anterior to excretory pore. The anterior head end is comparatively broader while the posterior caudal end is pointed. The anal opening lies at a distance of 0.20-0.25 from posterior end.

Remarks

The present larval forms appear to be 3rd stage developing larvae. The first two stages occur in eggs. In the present specimens the membranous lips does not indicate proper development except the formation of an oesophagus and a proper intestine which leads into anal opening. Bilqees and Fatima (1986) reported Anisakis larvae type 1=PA1 from fish Cybium guttatum, Pseudosciaena diacanthus, Muraenesox cinereus, Pampus argenteus, Chondroplites chinensis, Parastromateus niger, Arius serratus, Hilsa ilisha, Pomadasys olivaceus, Chiloscyllium griseum, Stegostoma varium, Galeocerdo arcticus, and Mugil spp. in stomach, intestine, liver, spleen, heart, testes, visceral mesenteries, connective tissues and body cavity. Anisakis larva type 2=PA2 from fish Cybium guttatum, Pseudosciaena diacanthus, Muraenesox cinereus, Pampus argenteus, Chondroplites chinensis, Parastromateus niger, Arius serratus, Hilsa ilisha, Pomadasys olivaceus, Chiloscyllium griseum, Stegostoma varium, Galeocerdo arcticus, and Mugil spp. in stomach, intestine, liver, spleen, testes, visceral mesenteries and connective tissues.

Further surveys are required for Anisakis species larvae present in fish of Karachi coast, Pakistan is crucial to ensure food safety, since the worms being present in the fish may be a threat to their health.

Acknowledgement

The authors are thankful to Dr. D.I. Gibson British Museum, Natural History, London for helping in identifying the worms.

Novelty Statement

Severe infection was seen in fish Mugil cephalus with Raphidascaris larvae.

Author’s Contribution

Aly Khan and Faiza Saleem: Prepared manuscript.

Rafia Rehana Ghazi: Prepared diagrams.

Nasira Khatoon and Mian Sayed Khan: Provided literature.

Samina Waheed: Typed the manuscript.

Conflict of interest

The authors have declared no conflict of interest.

References

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