{'fraction_non_alphanumeric': 0.03258472846059616, 'fraction_numerical': 0.01976316864026133, 'mean_word_length': 5.361558441558442, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Lymphocystic Disease in Wild Croaker (Micropogonias furnieri) and Flounder (Paralichthys orbignyanus)

Lymphocystis disease has been reported worldwide in several species of freshwater fish and marine fish, naturally infected in the wild environment, or in intensive crops in farms. Nodular warty lesions of irregular surface were observed in the tegument and fins and mouth in a species of croaker (Micropogonias furnieri) caught in Cassino beach Rio Grande RS, Brazil and flounder (Paralichthys orbignyanus) caught in the city of San Clemente, Argentina. The skin lesions fragments were fixed in 20% buffered formalin, and the histological sections were stained with hematoxylin and eosin and Original Research Article Pedrosa et al.; AJRIZ, 3(3): 29-36, 2020; Article no.AJRIZ.60333 30 Periodic Acid-Schiff (PAS), where microscopic alterations were visualized in the form of hyaline capsule with small basophilic structures in nodules and fibroblastic cells proliferation. The reported cases were based on the disease macroscopic findings characteristic of a lymphocystis disease, along with the histopathology, which confirmed the presence of the disease in the analyzed tissues.


INTRODUCTION
Lymphocystis disease is a viral disease caused by an iridovirus and one of the first viral diseases reported in fish in the 19th century, being first diagnosed in the year 1874 [1]. However, the viral agent was identified by means of electronic microscopy only in 1962 [2] and, subsequently, the virus was isolated from the lineage BF-2 [3]. Structurally, they are large icosahedral viral particles, with variable size from 120 to 340 nm in diameter, depending on the host fish species [4,5]. Although there are studies about the agent of the disease, the disease pathogenesis is still not clearly known [6], being reported as belonging to the genus Lymphocystivirus, within which is inserted the lymphocystis disease virus 1 (LCDV-1) originally isolated from the European flounder Platichthys flesus (Linnaeus, 1758) and from the European plaice, Pleuronectes platessa (Linnaeus, 1758), also included three candidates to the virus in this genus: LCDV-2, isolated from common Limanda limanda (Linnaeus, 1758); LCDVC, isolated from the Japanese plaice, Paralichthys olivaceus (Temminck and Schlegel, 1846); and LCDV-RF, isolated from the black scabbardfish, Sebastes schlegelii (Hilgendorf, 1880). The virus of the lymphocystis disease 1 and other related viruses are identified by means of host specificity, histopathology and profile of viral protein and DNA sequences [7].
The virus structure has stability to the pH between 6-9, being resistant to treatment with ultrasound [8], but demonstrate thermal instability, may be inactivated in Ether, glycerol, 5-iododeoxyuridine and UV treatments [1,9], in addition to the decrease of viral infectivity after freezing -thawing cycles at 20°C [3].
The lymphocytic disease has been reported worldwide in several species of freshwater fish and marine, naturally infected in the wild environment, or in intensive crops in farms [5,[10][11][12][13][14][15][16][17]. The viral transmission among animals is an important fact in the spread of the disease, since it can occur horizontally through the skin and gills of fish by direct contact among them, being facilitated by traumas in handling, parasitism and animals' aggressive behavior when maintained at high population densities, and simply by exposure in the virus presence in the water [1,18,19] and in feeding, since artemia nauplii (Artemia sp.) and rotifers (Brachionus plicatilis) may act as virus reservoirs [20,21]. The vertical form of viral transmission may also occur through infected eggs [21].
The disease although is not considered a fatal course and not be a zoonotic disease, has characteristics in fish affected that hinder their commercialization, mainly due to external lesions, where this aspect generates repulsion from the consumer, which leads to economic losses to producers [22]. These characteristics include nodular lesions on the skin of infected animals, being observed microscopically hypertrophy of fibroblasts in the dermis connective tissue, proliferating occasionally as true epithelial tumors on the body surface area [23]. The nodular lesions may be isolated or grouped, rarely being found in the internal organs. Each node represents an infected host cell, which is called lymphocyst or lymphocyst cell [24,25], usually associated to the tissue of the skin and fins, with probable viral multiplication only in fibroblastic cells [26].
The illness itself does not generate high mortalities, since the host in general recovers in a few weeks [27], however, when there is an invasion of bacteria in the lymphocyst lesion site, such infections can be fatal to the animal, already being reported a mortality rate of 90% in Paralichthys olivaceus after possible bacterial infection secondary to the lymphocyte disease [28].
The lymphocyst disease is often confused with neoplastic lesions or parasitary etiology being necessary a proper diagnosis to take appropriate prophylactic measures in the spread of the disease, since the transmission occurs quickly, and may cause serious mortalities without identifying the cause correctly. Here two cases are reported of the disease in different places, with some similar climatic characteristics, which may be a relevant point in their occurrence. Both species are considered to have potential for aquaculture, with studies showing good condition factors for M. furnieri raised in net tanks [29] and the flounder, P. orbignyanus, is already a known species in the commercial and recreational area, inhabiting marine and estuarine waters from Brazil (Rio de Janeiro) to Argentina (San Matías Golfo) [30].  species are considered to have potential for aquaculture, with studies showing good condition raised in net tanks [29] , is already a known species in the commercial and recreational area, inhabiting marine and estuarine waters from Brazil (Rio de Janeiro) to Argentina (San Matías Golfo) [30]. (Figueiredo e HODS Nodular warty lesions were observed of irregular surface in the tegument and fins and mouth in a Micropogonias furnieri) measuring 19 cm in length and 70.4 g in weight ( Fig. 1) a group of animals kept in Cassino beach Rio Grande RS, Brazil and wild flounder (Paralichthys orbignyanus) measuring 36 cm in length and 575 g in weight, captured in the city of San Clemente, in Buenos Aires, Argentina (Fig. 2).
The animals were euthanized in benzocaine hydrochloride (300 mg/L) and the autopsy was performed for material collection for histopathological analysis. The skin lesions fragments were fixed in 20% buffered formalin. The tissue samples were subjected to histological processing (LEICA TP 1020) and included in paraplast. The tissue sections were performed to a thickness of 5µ in the microtome Leica RM2245. The histological sections were stained with hematoxylin and eosin and periodic acid-Schiff (PAS).

Paralichthys orbignyanus nodular, warty aspect and congestive lesions in the oral region (arrow)
; Article no. AJRIZ.60333 ) measuring 36 cm in length and 575 g in weight, captured in the city of enos Aires, Argentina The animals were euthanized in benzocaine hydrochloride (300 mg/L) and the autopsy was performed for material collection for histopathological analysis. The skin lesions fragments were fixed in 20% buffered formalin. The tissue samples were subjected to stological processing (LEICA TP 1020) and included in paraplast. The tissue sections were performed to a thickness of 5µ in the microtome Leica RM2245. The histological sections were stained with hematoxylin and eosin and periodic with warty aspect nodular lesions in the tegument nodular, warty aspect and congestive lesions in

RESULTS AND DISCUSSION
In the histopathological examination, microscopic changes were observed in the form of hyaline capsule with small basophilic structures in nodules and proliferation of fibroblastic cells (Fig. 3). These cases of LCDV were diagnosed in wild animals which imply that the virus is found in the natural environment. These cases of LCDV were diagnosed in wild animals which imply that the virus is found in the natural environment. This fact is reported in the literature that most cases are of animals raised in aquaculture farms [5,6,8,17,31]. Macroscopically, the animals had nodular lesions measuring approximately 1-2 mm, warty aspect and irregular surface, with coloring cream to reddish ( Figs. 1 and 2), each node representing a cell infected by LCDV, also called lymphocyst or lymphocyst cell [25]. The infected cell staining (nodules), or infected clustered cells may vary when the dermis epithelial tissue is rich in chromatophores, which can modify the coloring to darker shades [32].
The virus shows affinity for replication in dermal fibroblasts, resulting in hypertrophied cells mainly on the dermis and flippers [26], which can be evidenced in the lesion microscopic characteristics (Fig. 3). In addition to the fibroblasts, some authors suggest other cell types target of infection, such as hepatocytes and cells of mononuclear phagocytic system [33], not being frequent cases of localized lesions in the eyes and internal organs with systemic involvement [1], which has been discussed by some authors that describe the systemic involvement being considered only in experimental cases, while other authors reported the occurrence of disease by natural means [34,35,36]. In a study on the virus tissue location after experimental infection intravenously,the hypothesis was raised that the distribution of antigen in blood cells was negative for the presence of LCDV, revealing that the virus could infect red blood cells which can only infect certain types of leukocytes, which would probably cause the entry of the virus structure in the bloodstream, generating a systemic infection [37]. The cytoplasm undergoes changes, developing intracytoplasmic basophilic inclusion bodies as dense vacuolated bodies [26], which can be seen in Fig. 3. This cell standard has already been reported in other studies [38], which indicate that the histopathology allows us a diagnosis of the disease characterized by fibroblastic cells with basophilic cytoplasm and prominent nuclei, discarding the differential diagnosis of a neoplastic lesion or parasitic etiology. The presence of hyaline capsule can also be evidenced by means of the Periodic Acid-Schiff (PAS) technique (Fig. 4), where a thick hyaline capsule can be observed circling the infected hypertrophied fibroblast, which according to some authors can be seen especially in mature lymphocyst cells [26]. The disease molecular diagnosis, although provides accuracy in the agent identification, represents a method that is more expensive and, depending on the virus protein profiles, needs more time for the diagnosis conclusion [26].
The two cases here reported in different regions, but with similar climatic characteristics, raises an important point in the occurrence of the disease, since some authors have already reported the importance of temperature in the virus persistence on the Japanese plaice tissue, where it was noted that at temperatures of 10°C, LCDV may persist for long periods on the fish epidermis in the form of a subclinical infection, coming to demonstrate clinical signs and presence of lymphocyst cells at temperatures of 20°C, considered ideal for the virus infectivity [39]. Inadequate conditions in cultivation may also influence in the disease clinical manifestation, such as high densities in the tanks, excessive manipulation, low salinity, low dissolved oxygen, nutritional deficiencies and water biological pollution [18,25,40,41,42,43,44,45,46], which is a point to be considered, since the fish could be in stress situations in the tanks where they were being kept.

CONCLUSION
The reported cases were based on the clinical and macroscopic aspects of lymphocyst disease, along with the histopathology, which confirmed the presence of the disease in the analyzed tissues, demonstrating that it is a method that is fast and effective, not being necessary to resort to other methods for a conclusive diagnosis of the disease.