Parasites of Callinectes amnicola and Cardisoma armatum Crabs in Degema LGA, Rivers State, Nigeria

Abstract

Aim: Parasite infestation/infection of crabs are a public health concern in Nigeria especially in the riverine regions due to possible zoonoses after crab consumption by humans. Therefore, a comparative study was conducted to evaluate the parasites of Callinectes amnicola and Cardisoma armatum crabs in Degema LGA, Rivers State, Nigeria. Study Design: A cross-sectional randomized study Place and Duration of Study: The study was conducted in Bakana town, Degema Local Government Area, Rivers State, Nigeria from July to December 2024. Methodology: In this study, 700 randomly selected crabs (350 Callinectes amnicola and 350 Cardisoma armatum) from the Bakana reaches of the New Calabar River, Nigeria were examined. The body parts (appendages, external regions, gills, gastro-intestinal tract and haemolymph) of the crabs were analyzed for parasites using standard laboratory techniques. All data generated were analyzed statistically using student T test and analysis of variance (ANOVA) with Turkey’s HDS post hoc as well as all statistical results were considered significant at P<0.05. Results: An overall parasite prevalence of 530 (75.7%) was recorded (P < 0.05); parasite prevalence of 250 (71.4%) and 280 (80.0%) were recorded for C. amnicola and C. armatum respectively. Male and female crabs had an overall parasite prevalence of 240 (77.4%) and 290 (74.4%) respectively. For weight, C. amnicola had a parasite prevalence of 40 (66.7%), 110 (78. 6%) and 100 (66.7%) for 21 – 50g, 51 – 80g, 81 – 120g respectively (P > 0.05) while C. armatum had a parasite prevalence of 180 (75.0%), 70 (87.5%) and 30 (100.0%) for 61 – 120g, 121 – 180g and 181 – 240g respectively. For carapace width, C. amnicola had a parasite prevalence of 40 (66.7%), 110 (78. 6%) and 100 (66.7%) for 7.1 – 9.0cm, 9.1 – 11.0cm, 11.1 – 14.0cm respectively while C. armatum had a parasite prevalence of 250 (78.1%) and 30 (100.0%) for 4.1 – 7.0cm and 7.1 – 10.0cm respectively. The parasites observed in this study were Cheloniba, Ergasilus, Monocystis, Gregarine, Myxidium, Hystherothylacium, Enterobius, Neoaplectana, Branchionus, Habrotrocha, Scepanotrocha, Otostephanos and Adineta with parasite abundance of 112 (23.4%) and 234 (67.6%) for Callinectes amnicola and Cardisoma armatum crabs respectively P<0.05). Conclusion: Although most parasites recorded in the study were not of zoonotic importance, crabs should always be washed and cooked properly before human consumption.