Canine gastrointestinal pythiosis: a case report in Brazilian Pantanal from a diagnostic approach / Pitiose gastrointestinal canina: relato de caso no Pantanal brasileiro a partir de uma abordagem diagnóstica

Pythiosis is caused by an aquatic fungus-like organism (Pythium insidiosum). It is considered an important public health issue as it can affect both animals and humans. This paper reports a case of gastrointestinal pythiosis in a dog. The patient was hospitalized for four days, during which the animal received supportive and symptomatic treatment. But the applied treatment was unsuccessful and the dog's clinical condition worsened, culminating in death. Complementary imaging tests such as radiography and ultrasonography, as well as hematological tests, were performed during the hospitalization period. The definitive diagnosis was reached in the postmortem as macroscopic and microscopic characteristics suggested the presence of intestinal granuloma and accentuated multifocal suppurative necrotic enteritis. Additionally, the histological evaluation revealed morphological structures compatible with P. insidiosum. Also, the results of nested PCR performed showed partial amplification (105 bp) of the ITS1 region of the ribosomal gene of P. insidiosum.(AU)

A pitiose é causada por um organismo aquático semelhante a um fungo (Pythium insidiosum) e considerada um importante problema de saúde pública, pois pode afetar animais e humanos. Este artigo relata um caso de pitiose gastrointestinal em um cão. O paciente ficou internado por quatro dias, período em que o animal recebeu tratamento de suporte e sintomático. No entanto, o tratamento aplicado não teve sucesso e o quadro clínico do cão piorou, culminando com a morte. Exames de imagem complementares, como radiografia e ultrassonografia, bem como exames hematológicos, foram realizados durante o período de internação. O diagnóstico definitivo foi feito na autópsia, pois as características macroscópicas e microscópicas sugeriam a presença de granuloma intestinal e acentuada enterite necrótica multifocal supurativa. Além disso, a avaliação histológica revelou estruturas morfológicas compatíveis com P. insidiosum. Além disso, a nested PCR foi realizada e mostrou amplificação parcial (105 pb) da região ITS1 do gene ribossomal de P. insidiosum.(AU)

Eosinophils participate in modulation of liver immune response and tissue damage induced by Schistosoma mansoni infection in mice.

The severity of chronic schistosomiasis has been mainly associated with the intensity and extension of the inflammatory response induced by egg-secreted antigens in the host tissue, especially in the liver and intestine. During acute schistosomiasis, eosinophils account for approximately 50% of the cells that compose the liver granulomas; however, the role of this cell-type in the pathology of schistosomiasis remains controversial. In the current study, we compared the parasite burden and liver immunopathological changes during experimental schistosomiasis in wild-type (WT) BALB/c mice and BALB/c mice selectively deficient for the differentiation of eosinophils (ΔdblGATA). Our data demonstrated that the absence of eosinophil differentiation did not alter the S. mansoni load or the liver retention of parasite eggs; however, there were significant changes in the liver immune response profile and tissue damage. S. mansoni infection in ΔdblGATA mice resulted in significantly lower liver concentrations of IL-5, IL-13, IL-33, IL-17, IL-10, and TGF-ß and higher concentrations of IFN-γ and TNF-α, as compared to WT mice. The changes in liver immune response observed in infected ΔdblGATA mice were accompanied by lower collagen deposition, but higher liver damage and larger granulomas. Moreover, the absence of eosinophils resulted in a higher mortality rate in mice infected with a high parasite load. Therefore, the data indicated that eosinophils participate in the establishment and/or amplification of liver Th-2 and regulatory response induced by S. mansoni, which is necessary for the balance between liver damage and fibrosis, which in turn is essential for modulating disease severity.

Case Report: Granulomatous Amebic Encephalitis due to Acanthamoeba spp. in an Immunocompetent Pediatric Patient.

Granulomatous amebic encephalitis (GAE) caused by Acanthamoeba is a rare infection with central nervous system (CNS) involvement usually with fatal consequences. Currently, information regarding GAE in children is scarce and is limited only to case reports and case series. A 13-year-old immunocompetent male patient with a 6-month history of progressive and intermittent headaches presented to our institution. One week before hospital admission, the patient showed signs of CNS involvement. Magnetic resonance imaging revealed multiple lesions with supra- and infratentorial cerebral abscesses. An empiric treatment with combined antibiotics was given, but the patient died after 20 days of hospital stay. A postmortem diagnosis confirmed GAE. Although it is a rare disease in pediatric patients, GAE should be considered in children with a chronic history of fever, headache, and vomiting with CNS involvement.

The potent effect of silymarin combination with Praziquantel or mirazid for Schistosoma mansoni treatment in infected male swiss albino mice.

This work was carried out to investigate the effect of silymarin combination in the therapeutic plane of schistosomiasis with praziquantel or mirazid to enhance the liver and reduce fibrosis. Mice were divided into 2 main groups, the 1st uninfected group served as control and the 2nd group infected subcutaneously with 60 cercaria of S. mansoni per each. The infected group was subdivided into 5 subgroups, the 1st kept untreated, the 2nd and 3rd treated at the 7th week of infection with (600 mg/kg) of PZQ orally for 3 consecutive days, while the 3rd treated also orally with (150 mg/kg) of silymarin daily for 11 weeks. The 4th and 5th groups treated orally at the 7th week of infection with 600 mg/kg of MZ for 3 consecutive days, while the 5th group treated orally also with 150 mg/kg of silymarin daily for 11weeks. IgG determination showed high level in the untreated infected group. Furthermore, the infected groups treated with PZQ and PZQ with silymarin displayed the lower levels than treated with MZ. Additionally, the untreated infected group showed severe pathological changes as hyaline degeneration, inflammation, presence of worm burdens in dilated portal veins, granulomas as well as depositions of collagenous and reticular fibers indicated intense fibrosis. Treatment with PZQ alone resulted in reduction of pathological signs and decreasing of granulomas. Combination with silymarin to PZQ therapy revealed more improvement for liver besides to lowering of granulomas areas and volumes and decreasing of fibrosis. Whereas, treatment with MZ was less effective than PZQ to reduce granulomas areas, volumes and fibrosis. Although, combination of silymarin to MZ treatment resulted in more curative signs and reduction of granulomas areas, volumes and fibrosis. Furthermore, the present study concluded that PZQ still the more effective drug of schistosomiasis treatment than MZ. The silymarin is very useful in schistosomiasis treatment when combined with PZQ or MZ due to its anti-fibrotic effect.

Identification of Metabolically Quiescent Leishmania mexicana Parasites in Peripheral and Cured Dermal Granulomas Using Stable Isotope Tracing Imaging Mass Spectrometry.

Leishmania are sandfly-transmitted protists that induce granulomatous lesions in their mammalian host. Although infected host cells in these tissues can exist in different activation states, the extent to which intracellular parasites stages also exist in different growth or physiological states remains poorly defined. Here, we have mapped the spatial distribution of metabolically quiescent and active subpopulations of Leishmania mexicana in dermal granulomas in susceptible BALB/c mice, using in vivo heavy water labeling and ultra high-resolution imaging mass spectrometry. Quantitation of the rate of turnover of parasite and host-specific lipids at high spatial resolution, suggested that the granuloma core comprised mixed populations of metabolically active and quiescent parasites. Unexpectedly, a significant population of metabolically quiescent parasites was also identified in the surrounding collagen-rich, dermal mesothelium. Mesothelium-like tissues harboring quiescent parasites progressively replaced macrophage-rich granuloma tissues following treatment with the first-line drug, miltefosine. In contrast to the granulomatous tissue, neither the mesothelium nor newly deposited tissue sequestered miltefosine. These studies suggest that the presence of quiescent parasites in acute granulomatous tissues, together with the lack of miltefosine accumulation in cured lesion tissue, may contribute to drug failure and nonsterile cure.IMPORTANCE Many microbial pathogens switch between different growth and physiological states in vivo in order to adapt to local nutrient levels and host microbicidal responses. Heterogeneity in microbial growth and metabolism may also contribute to nongenetic mechanisms of drug resistance and drug failure. In this study, we have developed a new approach for measuring spatial heterogeneity in microbial metabolism in vivo using a combination of heavy water (2H2O) labeling and imaging mass spectrometry. Using this approach, we show that lesions contain a patchwork of metabolically distinct parasite populations, while the underlying dermal tissues contain a large population of metabolically quiescent parasites. Quiescent parasites also dominate drug-depleted tissues in healed animals, providing an explanation for failure of some first line drugs to completely eradicate parasites. This approach is broadly applicable to study the metabolic and growth dynamics in other host-pathogen interactions.

The effect of ivermectin alone and in combination with cobicistat or elacridar in experimental Schistosoma mansoni infection in mice.

Schistosoma mansoni is less susceptible to the antiparasitic drug ivermectin than other helminths. By inhibiting the P-glycoprotein or cytochrome P450 3A in mice host or parasites in a murine model, we aimed at increasing the sensitivity of S. mansoni to the drug and thus preventing infection. We assigned 124 BALB/c mice to no treatment, treatment with ivermectin only or a combination of ivermectin with either cobicistat or elacridar once daily for three days before infecting them with 150 S. mansoni cercariae each. The assignment was done by batches without an explicit randomization code. Toxicity was monitored. At eight weeks post-infection, mice were euthanized. We determined number of eggs in intestine and liver, adult worms in portal and mesenteric veins. Disease was assessed by counting granulomas/cm2 of liver and studying organ weight indices and total weight. IgG levels in serum were also considered. No difference between groups treated with ivermectin only or in combination with cobicistat or elacridar compared with untreated, infected controls. Most mice treated with ivermectin and elacridar suffered severe neurological toxicity. In conclusion, systemic treatment with ivermectin, even in the presence of pharmacological inhibition of P-glycoprotein or cytochrome P450 3A, did not result in effective prophylaxis for S. mansoni infection in an experimental murine model.

Diagnostic Utility of Biplex/Multiplex Polymerase Chain Reaction in Infectious Granulomatous Dermatitis in North Indian Population.

BACKGROUND: A definite diagnosis of infectious granulomatous dermatitis (IGD) is difficult for both practicing dermatologists and dermatopathologists due to overlapping clinical and histomorphological features. We aimed to explore the role of multiplex polymerase chain reaction (PCR) for identifying a definite etiological agent for diagnosis and appropriate treatment in IGD in formalin-fixed paraffin-embedded tissue. MATERIALS AND METHODS: Sixty-two cases of IGD were included, excluding leprosy. The histochemical stains including Ziehl-Neelsen, periodic acid-Schiff, and Giemsa were performed in all cases. A multiplex PCR was designed for detection of tuberculosis (TB) (IS6110 and mpt64), fungal infections (ITS1, ITS2; ZM1, and ZM3), and leishmaniasis (kDNA). The results of histomorphology, histochemical stains, and multiplex PCR were compared. RESULTS: Among 62 cases, the sensitivity rate of PCR detection for organisms was 16.7%, 0%, 100%, 72%, 75%, and 66.7% in patients with TB, suggestive of TB, leishmaniasis, fungal infections, and granulomatous dermatitis not otherwise specified and granulomatous dermatitis suggestive of fungus, respectively. The TB PCR using IS6110 primers was negative in all cases; however, PCR using mpt64 primers was positive in 33.33% cases of scrofuloderma. The histochemical stains including Ziehl-Neelsen for acid-fast bacilli, periodic acid-Schiff for fungus, and Giemsa for Leishman-Donovan bodies showed positivity in 11.3%, 43.5%, and 3.2%, respectively. CONCLUSION: A multiplex PCR (Mycobacterium tuberculosis, Leishmania, and panfungal) is highly recommended in all cases of IGD where an etiological agent is difficult to establish by skin biopsy and histochemical stains along with a clinicopathological correlation. This will augment in appropriate treatment and will reduce empirical treatment and morbidity in such patients.

Schistosoma mansoni Eggs Modulate the Timing of Granuloma Formation to Promote Transmission.

Schistosome eggs provoke the formation of granulomas, organized immune aggregates, around them. For the host, the granulomatous response can be both protective and pathological. Granulomas are also postulated to facilitate egg extrusion through the gut lumen, a necessary step for parasite transmission. We used zebrafish larvae to visualize the granulomatous response to Schistosomamansoni eggs and inert egg-sized beads. Mature eggs rapidly recruit macrophages, which form granulomas within days. Beads also induce granulomas rapidly, through a foreign body response. Strikingly, immature eggs do not recruit macrophages, revealing that the eggshell is immunologically inert. Our findings suggest that the eggshell inhibits foreign body granuloma formation long enough for the miracidium to mature. Then parasite antigens secreted through the eggshell trigger granulomas that facilitate egg extrusion into the environment. In support of this model, we find that only mature S. mansoni eggs are shed into the feces of mice and humans.

Granuloma formation and tissue pathology in Schistosoma japonicum versus Schistosoma mansoni infections.

Schistosomiasis is the most important helminth disease in the world from a public health perspective. S mansoni and S japonicum account for the majority of global intestinal schistosomiasis cases, and the pathogenesis is widely assumed to be fundamentally similar. However, the majority of research on schistosomiasis has been carried out on S mansoni and comparisons between the two species are rarely made. Here, we will discuss aspects of both older and recent literature where such comparisons have been made, with a particular focus on the pathological agent, the host granulomatous response to the egg. Major differences between the two species are apparent in features such as egg production patterns and cellular infiltration; however, it is also clear that even subtle differences in the cascade of various cytokines and chemokines contribute to the different levels of pathology observed between these two main species of intestinal schistosomiasis. A better understanding of such differences at species level will be vital when it comes to the development of new treatment strategies and vaccines.

Diffuse Unilateral Subacute Neuroretinitis Evolving With Submacular Granuloma.

DUSN is an infectious ocular disease that can lead to severe visual impairment and blindness. It usually occurs in young healthy individuals and depending on the stage of the disease, clinical presentation may range from mild vitritis and multifocal gray-white lesions in outer retina to optic atrophy.Parasites of different sizes and species have been proposed as the etiological agent of this disease. Thus, it is hypothesized that different infectious worms may be considered as the likely cause of a both autoimmune and toxic form of nematode retinopathy.Most patients present with already severe visual impairment and in the later stages of the disease, where the likelihood of improvement is low, despite therapy. In cases of early diagnosis, prompt treatment, whether with oral antihelmintic or direct photocoagulation of the worm, patients may show considerable visual improvement and have a more favorable prognosis.

Granulomas in parasitic diseases: the good and the bad.

Parasitic diseases affect more than one billion people worldwide, and most of them are chronic conditions in which the treatment and prevention are difficult. The appearance of granulomas, defined as organized and compact structures of macrophages and other immune cells, during various parasitic diseases is frequent, since these structures will only form when individual immune cells do not control the invading agent. Th2-typering various parasitic diseases are frequent, since these structures will only form when individual immune cells do not control the invading agent. The characterization of granulomas in different parasitic diseases, as well as recent findings in this field, is discussed in this review, in order to understand the significance of the granuloma and its modulation in the host-parasite interaction and in the immune, pathological, and parasitological aspects of this interaction. The parasitic granulomatous diseases granulomatous amebic encephalitis, toxoplasmosis, leishmaniasis, neurocysticercosis, and schistosomiasis mansoni are discussed as well as the mechanistic and dynamical aspects of the infectious granulomas.

Immunometabolism of Leishmania granulomas.

Leishmania are parasitic protists that cause a spectrum of diseases in humans characterized by the formation of granulomatous lesions in the skin or other tissues, such as liver and spleen. The extent to which Leishmania granulomas constrain or promote parasite growth is critically dependent on the host T-helper type 1/T-helper type 2 immune response and the localized functional polarization of infected and noninfected macrophages toward a classically (M1) or alternatively (M2) activated phenotype. Recent studies have shown that metabolic reprograming of M1 and M2 macrophages underpins the capacity of these cells to act as permissive or nonpermissive host reservoirs, respectively. In this review, we highlight the metabolic requirements of Leishmania amastigotes and the evidence that these parasites induce and/or exploit metabolic reprogramming of macrophage metabolism. We also focus on recent studies highlighting the role of key macrophage metabolic signaling pathways, such as mechanistic target of rapamycin, adenosine monophosphate-activated protein kinase and peroxisome proliferator receptor gamma in regulating the pathological progression of Leishmania granulomas. These studies highlight the intimate connectivity between Leishmania and host cell metabolism, the need to investigate these interactions in vivo and the potential to exploit host cell metabolic signaling pathways in developing new host-directed therapies.

An Insight into the Potential Parasitological Effect of Schistosoma mansoni Antigens in Infected Mice: Prophylactic Role of Cercarial Antigen.

Schistosomiasis is a multifactorial disease that includes environmental, behavioral, parasitic, vector, and host factors. This study aimed to assess the protective effect of single and polyvalent antigens from cercarial antigen preparations (CAPs), soluble worm antigen preparations (SWAPs), and soluble egg antigens (SEAs) which were used as candidate vaccines in an experimental model of Schistosoma mansoni-infected mice. The efficiency of the antigens was tested by determining their effects on fecal egg count, egg viability analysis, and tissue egg counts. Histological and morphometric analyses of granulomas in liver and intestine tissues were performed. In the present study, all immunized groups showed a significant reduction in the average fecal egg count and tissue egg load compared with infected mice. The most substantial reduction in fecal egg count was observed in the combined vaccinated group (23.23 ± 3.2). The group vaccinated with CAP before infection showed the highest reduction in tissue egg load (liver and intestine: 85.22 and 91.70%, respectively). Immunized animals showed a highly significant reduction in the numbers of hepatic granulomas compared with the infected non-immunized group. In conclusion, combining these different antigens (CAP, SWAP, and SEA) augments the protective immunity compared with other immunized groups.

IL-17A-producing γδ T cells promote liver pathology in acute murine schistosomiasis.

BACKGROUND: The main symptoms of schistosomiasis are granuloma and fibrosis, caused by Schistosoma eggs. Numerous types of cells and cytokines are involved in the progression of Schistosoma infection. As a class of innate immune cells, γδ T cells play critical roles in the early immune response. However, their role in modulating granuloma and fibrosis remains to be clarified. METHODS: Liver fibrosis in wild-type (WT) mice and T cell receptor (TCR) δ knockout (KO) mice infected with Schistosoma japonicum was examined via Masson's trichrome staining of collagen deposition and quantitative reverse transcriptase-PCR (RT-PCR) of fibrosis-related genes. Granuloma was detected by hematoxylin-eosin (H&E) staining and quantified. Flow cytometry was used for immune cell profiling and for detecting cytokine secretion. The abundance of the related cytokines was measured using quantitative RT-PCR. RESULTS: The livers of S. japonicum-infected mice had significantly increased proportions of interleukin (IL)-17A producing γδ T cells and secreted IL-17A. Compared with the WT mice, TCR δ deficiency resulted in reduced pathological impairment and fibrosis in the liver and increased survival in infected mice. In addition, the profibrogenic effects of γδ T cells in infected mice were associated with enhanced CD11b+Gr-1+ cells, concurrent with increased expression of transforming growth factor (TGF)-ß in the liver. CONCLUSIONS: In this mouse model of Schistosoma infection, γδ T cells may promote liver fibrosis by recruiting CD11b+Gr-1+ cells. These findings shed new light on the pathogenesis of liver pathology in murine schistosomiasis.

A Surviving Case of Acanthamoeba Granulomatous Amebic Encephalitis in a Hematopoietic Stem Cell Transplant Recipient.

BACKGROUND Acanthamoeba are free-living amoebae with potential to infect immunocompromised hosts. The mortality rate of granulomatous amebic encephalitis (GAE) due to Acanthamoeba exceeds 90% and there are currently no reports of survival of this infection in recipients of hematopoietic stem cell transplant. CASE REPORT We report herein the case of a 32-year-old man presenting to our service with abrupt neurological deterioration and seizures 5 months after allogeneic stem cell transplantation for Hodgkin lymphoma. Clinical and imaging findings were non-specific at presentation. Multiple circumscribed, heterogenous, mass-like lesions were identified on MRI. Brain biopsy was performed and revealed multiple cysts and trophozoites suggesting a diagnosis of granulomatous amebic encephalitis. PCR testing confirmed Acanthamoeba. Treatment with miltefosine, metronidazole, azithromycin, fluconazole, pentamidine isethionate, and co-trimoxazole was instituted and the patient survived and shows continued improvement with intensive rehabilitation. CONCLUSIONS We report the first successful outcome in this setting. The diagnosis would have been missed on cerebrospinal fluid analysis alone, but was rapidly made by histological analysis of brain biopsy. This diagnostically challenging infection is likely under-recognized. Early brain biopsy and commencement of a prolonged miltefosine-containing anti-ameba regimen can be curative.

Dynamics of infection and pathology induced by the aporocotylid, Cardicola laruei, in Spotted Seatrout, Cynoscion nebulosus (Sciaenidae).

The sciaenid Spotted Seatrout (Cynoscion nebulosus) are infected by blood flukes (Cardicola spp.). A 2 year survey in estuaries of South Carolina, USA, showed that adult flukes and granulomas occurred throughout the year but their prevalence was highest in summer (61% and 84%, respectively), indicating an unusually high level of infection for wild fish. Granulomas remained after adult flukes could no longer be found. PCR-Restriction Fragment Length Polymorphism (RFLP) of a subsample of specimens allowed identification of Cardicola laruei as the only species infecting these seatrout during the period of study. Mean intensity of infection by flukes was higher in female seatrout, suggesting endocrine and/or immune system involvement. The prevalence of granulomas declined sharply in winter, indicating possible mortality of infected seatrout as this species is known to be cold-sensitive. Granulomas were studied using histology, immunohistochemistry, and transmission electron microscopy. Eggs were encapsulated by an inner core of dark epithelioid cells, and an outer core of large epithelioid cells undergoing epithelialization. Fibrosis was observed around granulomas and some granulomas detached from the surrounding damaged myocardium. Numerous inflammatory cells appeared mobilised around granulomas and pathology could be severe, in some cases showing grossly visible blister-like extrusions scattered in the damaged epicardium. At the gross level, some granulomas possessing eggs with live miracidia were observed at the surface of the epicardium. These findings suggest that granulomas carrying both dead and live eggs can clear the fish heart by host-mediated transport through the myocardium, as is known to occur in related human Schistosoma infections.

Schistosoma mansoni granulomas in the skeletal striated muscles in the murine model of neuroschistosomiasis: histological findings.

Schistosomiasis mansoni presents many clinical manifestations during migration of schistosomes in their hosts, including diarrhea, hepatomegaly, splenomegaly, liver abscesses, skinlesions, brain tumors and myeloradiculopathy. No lesions have been reported in skeletal striated muscles due to schistosomiasis mansoni in the literature. This short communication reports the histopathological findings on skeletal musculature in a murine model of neuroeschistosomiasis mansoni. Lesions were found in the tongue, masseter muscle, buccinator muscle, digastric muscle and temporalis muscle. Worm recovery was carried out to confirm the infection. We describe here, for the first time in the literature, injuries in the skeletal musculature due to Schistosoma mansoni nfection.

Suspected ocular toxocariasis and macular heterotopia.

We report a case of an asymptomatic Caucasian male who attended our clinic for a routine check-up and macular heterotopia associated with lesions compatible with ocular toxocariasis were found.

Bevacizumab as a potential anti-angiogenic therapy in schistosomiasis: A double-edged, but adjustable weapon.

AIM: Investigating the anti-angiogenic effect of bevacizumab on chronic schistosomiasis mansoni in a trial to hinder the Schistosome-induced angiogenesis and porto-systemic shunting complications. METHODS: The immunohistochemical expression of CD34, VEGF-R1, PCNA and α-SMA (angiogenesis markers) was analysed in the lung, liver and gastrointestinal junctions of chronic S mansoni infected mice after intraperitoneal injection of bevacizumab. The effect of prolonged administration of bevacizumab with praziquantel was also assessed through parasitic load, protective index, granuloma and fibrous tissue evaluation. RESULTS: A regression in the vascular activity and microvascular density was observed in the infected mice after receiving bevacizumab. They had a significantly less VEGF-R1, PCNA, CD-34 and α-SMA expression in comparison to the infected untreated mice. The least tissue egg count was reported in mice received bevacizumab for 6 weeks (Mean = 27 120). However, they had persistent liver granulomas, and massively amalgamated fibrosis. Interestingly, the least faecal egg and tissue worms counts (Mean = 112, 13.4), and the highest protection index (39.26) were reported in mice received bevacizumab for 3 weeks, with marked granuloma, and fibrous tissue resolution. CONCLUSIONS: Bevacizumab has a promising protective effect against the Schistosoma-induced angiogenesis. As an adjuvant to praziquantel, it is important to adjust the appropriate duration of administration that achieves the best schistosomicidal effect without impeding granuloma and fibrous tissue resolution.