Intensity of Echinorhynchus Veli (George and Nadakal) Infection in Relation to the Sex of the Host Synaptura Orientalis (Bloch and Schneider)

Received: 27/Jul/2018, Accepted: 18/Aug/2018, Online: 31/Oct/2018 AbstractIntensity of Echinorhynchusveli infection is more common in the fish. This study was conducted in department of Zoology, Mar Ivanios College, Nalanchira, Thiruvananathapuram, Kerala, India during the period of 2011-13. The fish samples were collected regular sampling of fish from Veli on the south-west coast of Kerala. In this state the winter season includes the months of January and February, followed by summer months of March, April and May. The rest of the year is the rainy season, which is divided into the South West Monsoon (June, July, August and September) and the North East Monsoon (October, November and December). The samples were collected and studied. In male and female the intensity of infection was high during the Monsoon season in the two annual cycles and low in summer and SW monsoon respectively. Echinorhynchusveli infection is more common in the rainy season.


INTRODUCTION
Parasites affected fish health, growth, behaviour, fecundity and mortality and also regulate host population dynamics and their community structure. Parasite development, parasite intensity and their consequences on host phenotype alteration should be studied simultaneously, as has been done in a few cases [1]. Echinorhynchusveli is an acanthocephalid worm, infecting the brackish water flat fish Synapturaorientalis, first reported from the Research Division, Department of Zoology, Mar Ivanios College, Thiruvananthapuram, Kerala [2]. The present study attributes towards the rate of infestation in fish and their intensity in different seasons. Extensive damage caused by acanthcephalan parasites on fish indirectly effect its growth, development and reproduction and thus, may leads to further decline in the population of the host fish. Heavy infestation of endoparasites interrupts the normal growth of fish. Kerala, experiences clear cut seasonal variations and host animals are available in all seasons of the year.A lot of studies were carried out on the intensity of Acanthocephala and other helminths. Prevalence and intensity of parasitic helminths of thicklip grey mullet Chelonlabrosus in hosts in Beymelek Lagoon Lake in Antalya, Turkey, according to season, host size, age, and sex of the host [3]. The effects of parasite age and intensity on variability in acanthocephalan induced behavioural manipulation [4].

II. MATERIALS AND METHODS
The study was conducted at Veli lake of Trivandrum district in Kerala. The flat fish Synapturaorientalis were collected from the fishermen of the locality during specific and definite intervals. The specimens were cut open to examine the intestines for the presence of the parasite, E. veli. The intestine of the host fish is placed in physiological saline for extraction of the parasite and for counting. ANOVA was used for statistical analysis.

III. RESULTS
In Kerala, the winter season includes the months of January and February. This is followed by summer months of March, April and May. The rest of the year is the rainy season, which is divided into the South West Monsoon (SW) (June, July, August and September) and the North East Monsoon (NE) (October, November and December).In male hosts, the mean and the seasonal intensity for the two annual cycles were NE monsoon 24.40, SW Monsoon 24.80, Summer 14.5 and Winter 14.10 (Table-2 and Figure-1). The highest intensity was observed in SW Monsoon months of June, July, August and September in both annual cycles and comparatively low in summer and winter (  Figure-2). Statistically there was no significant difference.

IV. DISCUSSION
In the present study, a total of 664 host fish were examined in a span of two years on a seasonal basis. During the first year 304 fish were examined and the second year, 360. Out of 664, 448 were infected. In this study was to assess the intensity of infection of male and female hosts. In males, the highest intensity was observed in monsoon and the lowest in summer. In females the highest was in NE monsoon and lowest in winter. In a study the parasites in edible fish species, they reported a mean intensity of 3.8 parasites/fish. The highest mean intensity (9.5) was recorded in April and zero intensity in May. In the present study the lowest male and female intensity was recorded in May (9.48 &10.58). The higher male and female intensity observed in the two monsoon seasons [5]. In the present study strengthens the view that feeding behaviour influences the intensity or the density of parasite population in the host fish. In the study reported higher helminth infection in female than in male host, Channapunctatus [6]. Highest mean intensity of infection (1270±942) in female horses [7]. The odds for males being infected with intestinal parasites were 2.8 higher than for females (P < 0.0001) [8]. Female guineafowls had a mean of 151.9 (CI 128.4-177.8) nematodes per host which was significantly more than the males that had a mean of 79.6 (CI 66.8-94) [9]. The present study revealed that seasons play a vital role in the intensity of E. veli infecting the host fish, S. orientalis.

V. CONCLUSION AND FUTURE SCOPE
The main conclusion of the study is rain session is the most common period for infection. Less number of samples was studied that is the major limitation of the study. There is a requirement of future histological studies for better results.  (NS*-Not Significant)