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White spot syndrome virus (WSSV) is one of the most prevalent, widespread and devastating pathogen associated with shrimp population. The present study was aimed at screening the wild caught shrimps from Andaman and Nicobar Islands (ANI) for WSSV infection. Shrimp samples of different penaeid species including and collected from nine different landing centers across the coast of ANI were screened for WSSV infection. Presence of white spots, a typical clinical sign of white spot disease was observed on the exoskeleton of WSSV infected shrimp samples. Out of 241 shrimp samples, 39 samples of were found positive for WSSV by nested PCR. Histopathological examination revealed eosinophilic to basophilic intranuclear inclusion bodies in gill tissue which are typical characteristics of WSSV infection. Nucleotide sequence of WSSV isolated from ANI showed 100% identity to the sequences of WSSV reported from Thailand, Taiwan, China, Egypt, Mexico, Korea, France and 99% identity to WSSV reported from India. The detection of WSSV in wild of ANI further confirms the virus spread and biogeography.

In the present study, we investigated the in vitro immunostimulatory effects of inactivated form of two potential probiotics, Bacillus amyloliquefaciens FPTB16 and B. subtilis FPTB13 in catla (Catla catla). Catla head kidney leukocytes (HK) were incubated with the bacteria alive or inactivated with heat shock (2 h at 60 °C), UV light (for 2.5 h) and formalin (1.0%, v/v) treatment (for 24 h at 4 °C) at different concentrations (10(7), 10(8) and 10(9) cells ml(-1)). After incubation, different cellular immune parameters such as respiratory burst activity, nitric oxide production, leukocyte peroxidase content and proliferative response were analyzed. The inactivated probiotic preparations stimulated all the cellular immune parameters of catla HK leukocytes in vitro. Among the different inactivated preparations, heat-treated form exhibited the best result. The lowest dose (10(7) cells ml(-1)) of both the strains showed the maximum stimulation. The results collectively suggest the efficacy of inactivated preparations to be used as immunostimulant in aquaculture.

In the present study, occurrence of branchial parasitic cymothoid, from the marine finfish, is reported for the first time from Andaman Islands. Morphological characterization was carried out which confirmed the parasite as Molecular characterization using 28S rDNA revealed 443 bp sequence which has been submitted to NCBI GenBank under the accession no. KX090447. Ten female and one male parasite () were collected from the branchial cavity of the individual host fishes (). The displacement of gill filament and cavity formation in the gill chamber of the host fish was observed. The report of this species from Andaman Islands gives further information on its geographic range extension, since they are currently known from West coast of India and Thailand.

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