Population dynamics of Enterogyrus cichlidarum (Monogenea: Ancyrocephalinae) from the stomach of Tilapia spp. in Egypt

Prevalencia de helmintos parásitos en peces (Salmo trutta y Schizothorax plagiostomus) en India

“…This can be attributed to many factors, viz., exposure time to different intermediate hosts, increase in body length and immunity with advancement of age. The above observations are in conformity with numerous findigns 1,10,14,15,17,18,24,25,26,28,29 . Another investigators studied the factors shaping the parasite communities of trout-perch found that the most prevalent parasite species increased with host age, relating to increased food intake and (or) shifts in dietary preference towards larger food items 26 .…”

“…Investigators have found an increase in mean worm burden with an increase in fish length 15 . The increased prevalence with increase in fish length may be due to the increase in growth of the internal organs of the hosts leading to the increase in the surface areas of infection 10,14,18 or could be due to the exposure time of infection 26 . Some investigators, while working on dynamics of Pseudodactylogrus anguilla in Eel, Anguilla anguilla (England), found that there exists a positive correlation between host size and parasitic burden 29 .…”

“…In order to study the relation between age and prevalence of helminth infection in fishes, the examined specimens were categorized into three groups: less than one year, 1-2 years, and above 2 years. It was observed that the prevalence was higher in age group of 1-2 years i.e., 18 (Nº E = n examined; Nº I = n infected; Nº AO = A. oreini; Nº RG = R.guptii; Nº CF = C. fotedari). 18.18% and 12% of C. fotedari in the age group of 1-2 years, above 2 years and below 1 year was observed respectively (Table 6).…”

Infestation Level and Spatial Distribution of Protoancylodiscoides Mansovrensis El-Naggar 1987, a Monogenean Gill Parasite From the Long Fin Catfish Chrysichthysauratus Geoffroy, 1809

“…The increase in the surface area of the gills of older and perhaps longer fish hosts (Cone and Burt, 1984) could be also an attribution. Khidr (1990) hypothesized that Oreochromis niloticus niloticus and Tilapia zillii accumulate more and more parasites as they get older. Similar increase of the infestation level with an increase in fish length was reported by Srivastava and James (1967) in Gyrodacfyhis inedius from Onosmvstehts species and by Buchmann (1989) in Pseudodactyhgyrus cmguiliae and P. bin?…”

“…1989;Hayward ei al.. 1998;Hagras ei al., 2001), Host length was reported by many authors to exhibit either a positive (Buchmann, 1989;Lo et aU 1998;and Zelmer and AraL 1998) or negative (Shotter, 1973: Khidr, 1990) relationship with the prevalence and/or intensity offish parasites. Haas (1994) assumed that parasites that locate fish hosts through chemotaxis or phototaxis should have an infrapopulation size that is dependent on host size as larger hosts make better targets.…”