Guppy (Poecilia) Poeciliidae fish naturally infected with Lernaea cyprinacea parasites (Linnaeus 1758) in KSA

Background: The ornamental fish guppy (Poecilia reticulata) is a small colorful tropical cyprinid teleost fish. Lernaea cyprinacea (Anchor worm) are worldwide, crustacean copepod parasites that cause disease and mortality in several fish species of cultured or natural populations, especially wild-caught and pond-raised species of Poecilia. This study may be considered as a novel report from Kingdom of Saudi Arabia (KSA). Objective: The present study is an investigation of Lernaea isolates infecting apparently healthy Poecilia reticulate from KSA. Material and Methods: Guppy fish (Poecilia reticulata) were purchased two weeks prior to experiments. They were examined for parasitic infection and allowed to breed in the laboratory. They were observed for 15 days for appearance of infection by Lernaea spp. larva and adult parasites. The copepod specimens were removed by forceps, from different parts of the infected fish. Specimens were fixed in 70% alcohol, cleared in 90% lactic acid, mounted, and microscopically examined to identify the morphological features of L. cyprinacea. Results: After 15 days, L. cyprinacea were detected in the ventral, anal and caudal fins of several P. reticulata. Intense focal inflammation and hemorrhage was easily observed at the attachment site, which appeared red and ulcerated. Total prevalence of infection was 68.1% (32/47). The prevalence of infection in females (29/38; 76.3%) was greater than in males (3/9; 33.3%). Conclusion: P. reticulata may be considered as a newly recorded host of L. cyprinacea from KSA. PARASITOLOGISTS UNITED JOURNAL 142 Guppy (P. reticulata) is a small and colorful tropical ornamental teleost. It is a member of the family Poeciliidae(15) that undergo internal fertilization(16). Guppies, whose natural habitat is in northeast South America, were introduced to many countries and are now found all over the world. They are highly adaptable and thrive in many different environmental and ecological conditions(15). Male guppies, which are smaller than females, have ornamental caudal and dorsal fins, while females are duller in color. In several tropical countries they were used for biological control of mosquito larvae, the vectors of infectious malaria disease(17,18) and filariasis(19-21). The guppy became a model for biological studies because of its short generation interval, ease of breeding in laboratories, and the availability of many different strains(22-24). Although L. cyprinacea parasites infect a wide range of both fish culture and natural populations fishes, few species of Lernaea were described especially those infecting ornamental fishes that still require further research. This study investigates Lernaea infections in guppy (P. reticulata), the ornamental, small and colorful fish, in a sample from KSA. MAtEriAl And MEtHodS The present study was carried out in the laboratory of Zoological Research, Biology Department, Faculty of Science, Taif University, KSA. From a local breeder in El-Taif, KSA, 47 fish (38 females and 9 males) guppy (P. reticulata) specimens (only colored, active, healthy and sexually mature males and females) were purchased (Figure 1) and transferred to the aquaria two weeks prior to the examination. They were allowed to breed in the laboratory. The fish were daily examined for external copepod parasitic infection. All aquaria were provided with thermostats 100 W, thermometers, air pumps, air lines, and gravel cleaner or dip tube (Figure 2). The water in the aquaria was obtained from a header tank containing constantly aerated (dechlorinated) water composed of deionized water mixed with local tap water (5:1). The tap water was analyzed, and its specifications were as follows: pH 8.46; total dissolved saline 2.52 ppm; conductivity 0.0054 mS/cm. After 15 days, infection with the larvae and adult of copepod parasites was observed. The adult copepod specimens were removed by forceps from different parts of the infected fish; skin and pectoral, ventral and dorsal fins. Specimens fixed in 70% alcohol were cleared in 90% lacto phenol and mounted in dibutylphthalate polystyrene xylene (DPX). The mounted specimens were examined and photographed using a Zeiss light microscope(25). The morphological identification of the L. cyprinacea specimens was performed according to Robinson(26). Animal use followed a protocol approved and authorized by Institutional Animal Care and Use Committee (IACUC). Statistical analysis: The copepod preference for attachment sites on the host was recorded. Infestation parameters, prevalence and intensity were calculated by QP3.0 (Quantitative Parasitology 3.0). This parasitology software provides statistically correct medians to analyze the highly aggregated (right-skewed) frequency distributions exhibited by parasites. QP3.0 describes parasitic infections within a sample of hosts and compares parasitic infections across different samples of hosts. Mann-Whitny test was applied to test the significance difference in parasite number at ≤0.05 using SPSS.