Splenic Granulomas Research Articles

Comparative pathogenicity and histopathological analysis of Edwardsiella anguillarum intraperitoneal infection in milkfish (Chanos chanos), Nile tilapia (Oreochromis niloticus) and Asian seabass (Lates calcarifer).

Edwardsiella anguillarum, a highly virulent species within the Edwardsiella genus, causes significant mortality in milkfish farms in Taiwan. This study aimed to investigate the comparison of milkfish susceptibility, a newly identified host species in Taiwanese aquaculture, with other species Nile tilapia (Oreochromis niloticus) and Asian seabass (Lates calcarifer), to E. anguillarum, elucidating its pathogenicity across both seawater and freshwater aquaculture environments. The results showed milkfish exhibited the highest mortality rate of 85% within 48 h of infection, whereas Nile tilapia exhibited a mortality rate of 70% between the second- and tenth-day post challenge, and seabass exhibited a mortality rate of 25% between the second- and sixth-day post challenge. Gross lesions observed in milkfish included splenomegaly and haemorrhage, whereas Nile tilapia exhibited signs of ascites, exophthalmia and brain haemorrhage. Seabass displayed spleen granulomas and haemorrhage at the injection site. Histopathological analysis revealed common features across all three species, including multifocal necrosis, bacterial presence in the necrotic areas, serositis and oedema. Asian seabass also exhibited chronic lesions in the form of splenic granulomas. This study highlights the high susceptibility of milkfish and Nile tilapia to E. anguillarum, emphasizing the urgent need for further investigation into targeted vaccine development for these fish species. These results not only deepen our understanding of the differing levels of pathogenicity among the three species but also offer valuable insights for improving disease prevention and management strategies in aquaculture, including those applied within polyculture systems and for the maintenance of aquaculture water environments.

Nocardia seriolae mediates granulomatous chronic inflammation of spleen in Micropterus salmoides through necroptosis

Granulomatous chronic inflammation is a typical pathological characteristic of largemouth bass (Micropterus salmoides) infected by Nocardia seriolae, and it is also an important breakthrough to solve the problem of pathogen prevention and treatment.Spleen, the target organ of N. seriolae infection, is significant for studying pathogenic mechanism. However, histopathological characteristics and immunological molecular mechanisms of the development of splenic granulomas in fish have not been extensively studied. In the initial process of exploring the molecular mechanism of N. seriolae infectious splenic granuloma formation, we accidentally found positive signals of necroptosis-related gene by immunohistochemical staining, suggesting that necroptosis may be involved in the formation of granulomas.Nevertheless, the role of necroptosis in the formation of splenic granuloma is still unclear. In this study, we established a granuloma model in the spleen of largemouth bass infected by N. seriolae. Through multiple tissue staining, we compared splenic granulomas with hepatic and renal granulomas, and preliminarily clarified the histopathological characteristics of splenic granulomas and the formation pattern of fibrosis, calcium salt deposition and other lesions. Notably, we found that the expression of inflammatory factors and necroptosis-related molecules in spleen were significantly upregulated during N. seriolae infection. Further immunohistochemical staining showed that the splenic granulomas were accompanied by extensive and intense p-MLKL-positive signals in the peripheral tissue. In addition, western blot and immunofluorescence results showed that N. seriolae could induce necroptosis in primary spleen cells of largemouth bass in vitro. Our data indicated that necroptosis is closely related to the formation of splenic granulomas in largemouth bass, and provide some ideas for the study of the formation mechanism of fish granuloma.

Splenic Lesions as a Soft Pointer Towards the Diagnosis of Enteric Fever: A Case Series.

To the Editors: Enteric fever is a major public health problem in developing countries.1 The highest incidence is in children between 5 and 9 years-of-age.2 Splenic abscess (SA) is a rare extra-intestinal complication of salmonellosis with a reported incidence of 0.29%–2%.3,4 Salmonella SA is rare but carries a high risk of morbidity and mortality if unrecognized and untreated.5 This case series presents 3 cases of enteric fever complicated with splenic lesions. Case 1: A 5-year-old female patient presented with fever, pain in the abdomen, vomiting and loose stools for 10 days. On examination, she had a tender abdomen with hepatomegaly. She was started on ceftriaxone due to suspicion of enteric fever. Ultrasonography (USG) of the whole abdomen on admission day was normal. Widal serology on day 11 of illness was positive (1:320 for Titre of H antibody and Titre of O antibody). Blood culture grew nalidixic acid-resistant Salmonella typhi (Table 1). Because she continued to remain febrile, azithromycin was added on day 7 of the hospital stay, and a repeat USG was performed on day 10 of the stay, showing SA (1.4 × 2.1 × 2.3 cm) at the lower pole. USG-guided needle aspiration was performed, and antibiotics continued. She became afebrile over the next few days, was started on oral cefixime and discharged. TABLE 1. - Baseline Characteristics, Clinical, Lab and Management Details of Cases Patient Characteristics Case 1 Case 2 Case 3 Age at presentation (years) 5 12 4 Symptoms (duration in days) Fever Yes (10) Yes (21) Yes (10) Pain abdomen Yes (8) Yes (18) Yes (3) Vomiting Yes (8) No Yes (3) Loose stools Yes (8) No No Per abdomen examination Tenderness Yes Yes Yes Hepatomegaly (liver span) Yes (11 cm) Yes (12 cm) Yes (12 cm) Splenomegaly No Palpable spleen tip No Investigations at admission Haemoglobin (gm/dL) 9.3 11 11.5 TLC (per mm3) 7,800 8,260 5800 DLC (N%/ L %/ M %) 74/20/3 76/14/4 56/33/10 Platelet count (per mm3) 39,000 3,69,000 1,54,00 CRP (mg/dL) 97 36 43 Widal test (titres) Positive (1:320) Negative Positive (1:320) Antibiotics (days) Ceftriaxone (14) f/b cefixime (7) Azithromycin (14) Ceftriaxone (14) f/b cefixime (7) Ceftriaxone (14) f/b cefixime (7) Follow up USG 1 × 1.06 × 1 cm abscess, 1-month postdischarge. Resolution of splenic abscess, 2-month postdischarge Resolution of splenic abscess Resolution of splenic granuloma Typhoid vaccine status Unvaccinated Unvaccinated Unvaccinated CRP, C-reactive protein; DLC, Differential leukocyte count; f/b indicates followed by; TLC, Total leukocyte count; USG, ultrasonography. Case 2: A 12-year-old male presented with 3 weeks of high-grade fever and left abdominal pain. Examination revealed tenderness and palpable spleen tip. Ceftriaxone was initiated empirically. Widal serology was negative, and the blood culture was sterile. Other investigations to evaluate for the etiology of fever, including tuberculosis, were negative. USG abdomen revealed 3 SA, the largest 2.5 × 2.2 cm in splenic parenchyma. Ultrasound-guided aspiration of the largest abscess was performed. Pus culture grew Salmonella paratyphi A. Ceftriaxone was continued as per the sensitivity report. Subsequently, he became afebrile and was started on cefixime and discharged. Case 3: A 4-year-old female presented with fever for 10 days, pain in the abdomen, and vomiting for 3 days. She was started on intravenous ceftriaxone empirically, keeping a possibility of enteric fever. Due to persistent abdominal pain, USG of the abdomen was performed, which revealed multiple hypo-echoic foci in the spleen suggestive of splenic granuloma. Blood investigations revealed a positive Widal test (1:320 dilution titers for Titre of H antibody and Titre of O antibody) and blood culture grew Salmonella typhi. She became afebrile by day 4 of the hospital stay. She was given 7 days of intravenous ceftriaxone, followed by 7 days of cefixime. USG whole abdomen repeated 1-week post-discharge, showed no splenic granuloma. Salmonella SA is rare but carries a high risk of morbidity and mortality if unrecognized and untreated.5 Diagnosis is often delayed in children due to its rarity and nonspecific symptoms. USG abdomen is usually the first investigation performed in suspected cases, and sensitivity can be as high as 90% in the hands of an experienced operator. Percutaneous needle aspiration and antibiotics for 2–3 weeks may be sufficient in many cases, though the actual duration of antibiotics required is not known. The splenic abscess could be a pointer toward the diagnosis of enteric fever in high-burden settings like India. Though radiologic clearing can require 2–3 months, patients usually become asymptomatic after 2–3 weeks of adequate antibiotics and drainage.

Ataxic Gait and Back Pain in an Immunocompetent 5-Year-Old Boy

<em>Bartonella henselae</em> is a Gram-negative bacterium and the causative agent of Cat Scratch Disease (CSD). Atypical presentations of <em>B. henselae</em> that involve musculoskeletal, hepatosplenic, or neurologic systems are rare. In this case report, we describe a case of <em>B. henselae</em> osteomyelitis involving the thoracic spine at the level of T2, complicated by both hepatic and splenic granulomas in a 5-year-old generally healthy male patient. Although <em>B. henselae</em> is a rare cause of osteomyelitis, it should be considered in patients with a possible cat exposure, who present with fever, pain, and lymphadenopathy.

Concurrent occurrence of primary mesenteric hydatid cyst with multiple calcified splenic granulomas: A rare presentation

Concurrent occurrence of primary mesenteric hydatid cyst with multiple calcified splenic granulomas: A rare presentation

Conundrums in leishmaniasis

Parasites of the genus Leishmania cause the disease leishmaniasis. As the sandfly vector transfers the promastigotes into the skin of the human host, the infection is either cured or exacerbated. In the process, there emerge several unsolved paradoxes of leishmaniasis. Chronologically, as the infections starts in skin, the role of the salivary proteins in supporting the infection or the host response to these proteins influencing the induction of immunological memory becomes a conundrum. As the parasite invokes inflammation, the infiltrating neutrophils may act as “Trojan Horse” to transfer parasites to macrophages that, along with dendritic cells, carry the parasite to lymphoid organs to start visceralization. As the visceralized infection becomes chronic, the acutely enhanced monocytopoiesis takes a downturn while neutropenia and thrombocytopenia ensue with concomitant rise in splenic colony-forming-units. These responses are accompanied by splenic and hepatic granulomas, polyclonal activation of B cells and deviation of T cell responses. The granuloma formation is both a containment process and a form of immunopathogenesis. The heterogeneity in neutrophils and macrophages contribute to both cure and progression of the disease. The differentiation of T-helper subsets presents another paradox of visceral leishmaniasis, as the counteractive T cell subsets influence the curing or non-curing outcome. Once the parasites are killed by chemotherapy, in some patients the cured visceral disease recurs as a cutaneous manifestation post-kala azar dermal leishmaniasis (PKDL). As no experimental model exists, the natural history of PKDL remains almost a black box at the end of the visceral disease.

Salmonella-Driven Polarization of Granuloma Macrophages Antagonizes TNF-Mediated Pathogen Restriction during Persistent Infection

Many intracellular bacteria can establish chronic infection and persist in tissues within granulomas composed of macrophages. Granuloma macrophages exhibit heterogeneous polarization states, or phenotypes, that may be functionally distinct. Here, we elucidate a host-pathogen interaction that controls granuloma macrophage polarization and long-term pathogen persistence during Salmonella Typhimurium (STm) infection. We show that STm persists within splenic granulomas that are densely populated by CD11b+CD11c+Ly6C+ macrophages. STm preferentially persists in granuloma macrophages reprogrammed to an M2 state, in part through the activity of the effector SteE, which contributes to the establishment of persistent infection. We demonstrate that tumor necrosis factor (TNF) signaling limits M2 granuloma macrophage polarization, thereby restricting STm persistence. TNF neutralization shifts granuloma macrophages toward an M2 state and increases bacterial persistence, and these effects are partially dependent on SteE activity. Thus, manipulating granuloma macrophage polarization represents a strategy for intracellular bacteria to overcome host restriction during persistent infection.

&lt;i&gt;Salmonella&lt;/i&gt;-Driven Polarization of Granuloma Macrophages Counteracts TNF-Mediated Pathogen Restriction During Persistent Infection

Many intracellular bacteria can establish chronic infection and persist in tissues within granulomas comprised of macrophages. Granuloma macrophages exhibit heterogeneous polarized states, or phenotypes, that may be functionally distinct. Here, we elucidate a host-pathogen interaction that controls granuloma macrophage polarization and long-term pathogen persistence during Salmonella Typhimurium (STm) infection in vivo. We show that STm persists within splenic granulomas that are predominated by CD11b+CD11c+Ly6C+ macrophages. STm preferentially persists in granuloma macrophages reprogrammed to an M2 state, in part through the activity of the virulence factor SteE, which contributes to the establishment of persistent infection. We demonstrate that tumor necrosis factor (TNF) signaling limits M2 granuloma macrophage polarization thereby restricting STm persistence. Strikingly, in mice infected with ∆steE mutant STm, TNF signaling becomes dispensable for limiting M2 granuloma macrophages and pathogen persistence. Thus, manipulation of granuloma macrophage polarization represents a crucial pathogenesis strategy for intracellular bacteria to overcome host restriction during persistent infection.

Salmonella Persist in Activated Macrophages in T Cell-Sparse Granulomas but Are Contained by Surrounding CXCR3 Ligand-Positioned Th1 Cells

Salmonella enterica (Se) bacteria cause persistent intracellular infections while stimulating a robust interferon-γ-producing CD4+ T (Th1) cell response. We addressed this paradox of concomitant infection and immunity by tracking fluorescent Se organisms in mice. Se bacteria persisted in nitric oxide synthase (iNOS)-producing resident and recruited macrophages while inducing genes related to protection from nitric oxide. Se-infected cells occupied iNOS+ splenic granulomas that excluded Tcells but were surrounded by mononuclear phagocytes producing the chemokines CXCL9 and CXCL10, and Se epitope-specific Th1 cells expressing CXCR3, the receptor for these chemokines. Blockade of CXCR3 inhibited Th1 occupancy of CXCL9/10-dense regions, reduced activation of the Th1 cells, and led to increased Se growth. Thus, intracellular Se bacteria survive in their hosts by counteracting toxic products of the innate immune response and by residing in Tcell-sparse granulomas, away from abundant Th1 cells positioned via CXCR3 in a bordering region that act to limit infection.

Mycobacterium marinum is the causative agent of splenic and renal granulomas in half-smooth tongue sole (Cynoglossus semilaevis Günther) in China

The half-smooth tongue sole (Cynoglossus semilaevis Günther) is a major cultivated marine fish species of high economic value. However, splenic and renal granulomas disease is a major disease of C. semilaevis and results in high mortality; its first outbreak was reported in 2009, and the pathogen responsible was believed to be associated with an unidentified virus. In this study, we investigated the prevalence of this disease in three fish farms located in different cities; we isolated homogeneous colonies from affected fish from each farm. Healthy half-smooth tongue sole were subjected to bacterial challenge tests by intraperitoneal injection of 0.5 × 107 cfu/fish of the isolates from each farm. The accumulative mortality rate was >80% within 30 days post infection. Diseased sole displayed symptoms similar to those seen in naturally infected fish. These strains were all identified as Mycobacterium marinum based on bacterial morphology, analytical profile index identification and 16S rDNA sequencing. The results of this study suggest that M. marinum is the causal agent of splenic and renal granulomas disease in half-smooth tongue sole; therefore, more attention should be paid to the occurrence of this bacterium in the flat fish aquaculture industry in China.

Acute Brucella melitensis M16 infection model in mice treated with tumor necrosis factor-alpha inhibitors.

There is limited data in the literature about brucellosis related to an intracellular pathogen and anti-tumor necrosis factor alpha (anti-TNFα) medication. The aim of this study was to evaluate acute Brucella infections in mice receiving anti-TNFα drug treatment. Anti-TNFα drugs were injected in mice on the first and fifth days of the study, after which the mice were infected with B. melitensis M16 strain. Mice were sacrificed on the fourteenth day after infection. Bacterial loads in the liver and spleen were defined, and histopathological changes were evaluated. Neither the liver nor the spleen showed an increased bacterial load in all anti-TNFα drug groups when compared to a non-treated, infected group. The most significant histopathological findings were neutrophil infiltrations in the red pulp of the spleen and apoptotic cells with hepatocellular pleomorphism in the liver. There was no significant difference among the groups in terms of previously reported histopathological findings, such as extramedullary hematopoiesis and granuloma formation. There were no differences in hepatic and splenic bacterial load and granuloma formation, which indicate worsening of the acute Brucella infection in mice; in other words, anti-TNFα treatment did not exacerbate the acute Brucella spp. infection in mice.

An unusual presentation of Chlamydia pneumoniae infection in a Royal Python (Python regius)

Chlamydia species are a relatively newly recognised and emerging pathogen in reptile species. Chlamydia pneumoniae has been reported to cause infections in several snake species, as well as other reptiles...

Systemic lupus erythematosus with hepatosplenic granuloma: a rare case.

Background. Systemic lupus erythematosus (SLE) is an autoimmune disease which is known to present with a wide variety of clinical manifestations. Case Report. A 15-year-old male presented with complaints of moderate grade fever and generalized body swelling. There was no history of cough, weight loss, joint pain, oral ulcerations, skin rash, photosensitivity, loss of hair, pain abdomen, jaundice, or any significant illness in the past. Contrast enhanced computerized tomography of the abdomen revealed hypodense lesions in both liver and spleen (without contrast enhancement), suggestive of granulomas along with few retroperitoneal and mesenteric lymph nodes. On the basis of immunological tests and renal biopsy report, SLE with hepatosplenic granulomatosis diagnosis was made. He was given pulse methylprednisolone 500 mg, for 3 days and he showed dramatic improvement clinically. Conclusion. Hepatic and splenic granulomas are not common in SLE, but this should be kept in differential diagnosis.

613 cases of splenic rupture without risk factors or previously diagnosed disease: a systematic review.

BackgroundRupture of the spleen in the absence of trauma or previously diagnosed disease is largely ignored in the emergency literature and is often not documented as such in journals from other fields. We have conducted a systematic review of the literature to highlight the surprisingly frequent occurrence of this phenomenon and to document the diversity of diseases that can present in this fashion.MethodsSystematic review of English and French language publications catalogued in Pubmed, Embase and CINAHL between 1950 and 2011.ResultsWe found 613 cases of splenic rupture meeting the criteria above, 327 of which occurred as the presenting complaint of an underlying disease and 112 of which occurred following a medical procedure. Rupture appeared to occur spontaneously in histologically normal (but not necessarily normal size) spleens in 35 cases and after minor trauma in 23 cases. Medications were implicated in 47 cases, a splenic or adjacent anatomical abnormality in 31 cases and pregnancy or its complications in 38 cases.The most common associated diseases were infectious (n = 143), haematologic (n = 84) and non-haematologic neoplasms (n = 48). Amyloidosis (n = 24), internal trauma such as cough or vomiting (n = 17) and rheumatologic diseases (n = 10) are less frequently reported. Colonoscopy (n = 87) was the procedure reported most frequently as a cause of rupture. The anatomic abnormalities associated with rupture include splenic cysts (n = 6), infarction (n = 6) and hamartomata (n = 5). Medications associated with rupture include anticoagulants (n = 21), thrombolytics (n = 13) and recombinant G-CSF (n = 10). Other causes or associations reported very infrequently include other endoscopy, pulmonary, cardiac or abdominal surgery, hysterectomy, peliosis, empyema, remote pancreato-renal transplant, thrombosed splenic vein, hemangiomata, pancreatic pseudocysts, splenic artery aneurysm, cholesterol embolism, splenic granuloma, congenital diaphragmatic hernia, rib exostosis, pancreatitis, Gaucher's disease, Wilson's disease, pheochromocytoma, afibrinogenemia and ruptured ectopic pregnancy.ConclusionsEmergency physicians should be attuned to the fact that rupture of the spleen can occur in the absence of major trauma or previously diagnosed splenic disease. The occurrence of such a rupture is likely to be the manifesting complaint of an underlying disease. Furthermore, colonoscopy should be more widely documented as a cause of splenic rupture.

Role of Cytopathologic Diagnosis in a Case of Splenic Granulomata in an HIV Patient

Splenic granulomata are rare entities. These have typically been associated with the uncommon condition of splenic tuberculosis or part of miliary tuberculosis. Furthermore, the diagnosis of splenic granuloma is complex and makes the identification of the agent difficult, and this entity has rarely been diagnosed by cytopathologic methods. Review of the medical records revealed …

Pathology and molecular diagnosis of paratuberculosis of camels

Camels are the prime source of meat and milk in many desert regions of the world including Saudi Arabia. Paratuberculosis of camels, locally called Silag, is a serious and invariably fatal disease in the Arabian camel. Six camels were used in this study. Five camels with clinical paratuberculosis were used to study the pathology of the disease and confirm its aetiology. The sixth camel was clinically healthy and used as a control. The camels were examined clinically and bled for haematological and blood chemistry analysis. They were then humanely killed with a high intravenous dose of thiopental sodium (10 mg/kg) for pathological studies as well as obtaining tissues for microbiological and molecular studies. The clinical signs of the disease were emaciation, diarrhoea, alopecia, wry neck and pale mucous membranes. Laboratory diagnosis showed reduced haemoglobin concentration, low haematocrit and high activity of the serum enzyme alanine aminotransferase. Serum creatinine concentration was normal. These results indicated the infected camels were anaemic and the function of their livers was affected. Postmortem examination showed thickened and corrugated intestinal mucosa, enlarged granulomatous mesenteric lymph nodes, miliary and diffuse granulomas in the liver (in four camels), generalized lymph node granulomas (in one camel), splenic granuloma (in one camel) and mediastinal lymph node granuloma (in two camels). Histopathological examination showed diffuse infiltration of macrophages in all organs showing lesions. Ziehl-Neelsen staining of tissue scraping and tissue sections showed masses of acid fast bacilli, except for the spleen. Infection with Mycobacterium avium subsp. paratuberculosis was confirmed by PCR by targeting the IS900 gene.

Thein vivoimmunomodulatory effect of recombinant tumour necrosis factor-alpha in guinea pigs vaccinated withMycobacterium bovisbacille Calmette–Guérin

Previous studies from our laboratory demonstrated that treatment in vitro with recombinant guinea pig tumour necrosis factor TNF (rgpTNF)-α-enhanced T cell and macrophage functions. Similarly, injection of Mycobacterium tuberculosis-infected guinea pigs with anti-TNF-α altered splenic granuloma organization and caused inflammatory changes and reduced the cell-associated mycobacteria in the tuberculous pluritis model. In this study, rgpTNF-α was injected into bacille Calmette-Guérin (BCG)-vaccinated guinea pigs to modulate immune functions in vivo. Guinea pigs were vaccinated intradermally with BCG, 2 × 10(3) colony-forming units (CFU) and injected intraperitoneally with either rgpTNF-α (25 µg/animal) or 1% bovine serum albumin (BSA) for a total of 12 injections given every other day. Treatment with rgpTNF-α significantly enhanced the skin test response to purified protein derivative (PPD), reduced the number of CFUs and increased the PPD-induced proliferation in the lymph nodes at 6 weeks after vaccination. The levels of interleukin (IL)-12 mRNA were increased in the lymph node and spleen cells stimulated with PPD. TNF-α treatment induced a decrease in TNF-α, IL-12p40 and IL-10 mRNA levels in peritoneal cells following PPD stimulation while live M. tuberculosis caused an increase in TNF-α mRNA and a decrease in the IL-10 mRNA expression. TNF-α injection also induced an increase in the infiltration of mononuclear cells and in the proportions of CD3(+) T cells in the lymph nodes. These results indicate that rgpTNF-α enhances some aspects of T cell immunity and promotes control of mycobacteria in the tissues. Future studies will address the role of TNF-α in BCG-vaccinated guinea pigs following low-dose pulmonary challenge with virulent M. tuberculosis.

Splenic granulomas in a patient with severe Crohnʼs disease associated with multiple extraintestinal manifestations

Splenic granulomas in a patient with severe Crohnʼs disease associated with multiple extraintestinal manifestations

Milzbefall – seltene extraintestinale Manifestation bei Morbus Crohn

Extraintestinal manifestations of inflammatory bowel disease occur frequently in parallel to the inflammation in the bowel. The activity of extraintestinal manifestations is often divergent to the activity of intestinal inflammation. We here present the case of a rare extraintestinal manifestation of Crohn's disease and report on a 52-year-old patient with known Crohn's disease and primary sclerosing cholangitis (PSC) in clinical remission. Multiple lesions of the spleen were observed in routine MR tomography. The histological examination of a specimen obtained by MR-guided fine needle biopsy showed non-caseating epitheloid cell granulomas. The splenic granulomas regressed completely and spontaneously without specific immunmodulatory therapy.

Low prevalence of splenic mycobacteriosis in migratory striped bass Morone saxatilis from North Carolina and Chesapeake Bay, USA

Mycobacteriosis is a chronic bacterial disease causing an ongoing epizootic in striped bass Morone saxatilis in Chesapeake Bay, U.S.A. Prevalence of disease is high in pre-migratory fish, and multiple species of Mycobacterium spp. have been isolated. However, prevalence of mycobacteriosis in the coastal migratory population is unknown and is of concern to multiple coastal states, as disease-related mortality may impact the long-term health of the population. Histological examinations of spleens collected from fish caught by recreational anglers during the winter fishery in coastal North Carolina (2005-2006, n=249) and during the spring fishery in Chesapeake Bay (2006, n=120) indicated a low prevalence of mycobacteriosis (6.8% of all fish examined) in comparison to smaller, pre-migratory Chesapeake Bay fish. Genus-level PCR and subsequent sequencing of the 16-23S intergenic transcribed spacer (ITS) region revealed that all bacteria were phylogenetically related, but species is unknown. Location of survey, gender of fish, and total length of fish had no significant effect on prevalence of mycobacteriosis, parasitic granulomas, or the density of splenic granulomas (p > 0.05). These results may indicate that either granulomas resolve after Chesapeake Bay fish enter the coastal migratory population, or that there is disease-related mortality among pre-migratory Chesapeake Bay fish.