Paracoccidioides brasiliensis-associated dermatitis and lymphadenitis in a dog

Disseminated paracoccidioidomycosis in a captive western black-handed tamarin (Saguinus niger)

Paracoccidioidomycosis (PCM) is an endemic fungal disease that occurs in Latin America and primarily affects humans. The disease has been rarely documented in non-human primates. This report details a disseminated and fatal case of PCM caused by Paracoccidioides brasiliensis in a western black-handed tamarin (Saguinus niger) under human care. Histopathological examination revealed extensive pyogranulomatous inflammation in the lungs, spleen, liver, lymph nodes, kidneys, epididymis, right testicle, heart, adrenal gland and intestines, associated with characteristic yeast forms consistent with Paracoccidioides spp and confirmed by immunohistochemistry. Molecular analysis indicated a high nucleotide similarity with P. brasiliensis sequences for both the 18S rRNA and gp43 genes. This naturally occurring infection highlights the susceptibility of these animals to PCM and their role in ecoepidemiology warrants further investigation.

An atypical case of chronic paracoccidioidomycosis in a dog caused by a fungus from the Paracoccidioides brasiliensis complex

Paracoccidioidomycosis (PCM) is a systemic mycosis endemic in Latin American countries and one of the most important fungal diseases regarding incidence and mortality in humans. PCM has also been described in some animal species such as dogs. In this study we describe a new case of PCM disease in a dog that differed from previous records in the literature which includes a progressive evolution of fungal dermatitis causing a deforming lesion in the nose, like those found in human patients, and humoral response against gp70 instead of gp43, the major diagnostic antigen for human PCM. The clinical isolate through the ITS and partial gp43 gene phylogenetic analysis was grouped in the Paracoccidioides brasiliensis complex. This case describes several features which may contribute to improving diagnosis and understanding of canine paracoccidioidomycosis.

The pathology of canine mammary candidiasis with embolic dissemination in a dog

Candidiasis is a fungal disease caused by Candida albicans or other members of the genus Candida. Descriptions of candidiasis are comparatively reduced in veterinary relative to human medicine, with no cases of mammary candidiasis being identified in pet animals. This report presents the cytological, pathological, and molecular findings of mammary candidiasis with embolic dissemination in a postpartum dog. A 1-year-old, female Shih-tzu dog that had recently given birth was admitted to a veterinary teaching hospital in Southern Brazil after repeated episodes of intermittent mammary disease and a neurological syndrome. The dog was euthanized due to worsened clinical status and poor prognosis despite adequate clinical therapy and was submitted for routine post-mortem evaluation to determine the cause of the neurological manifestations. Cytological analysis of purulent mastitis identified intralesional fungal hyphae. Gross evaluation revealed multiple masses within the kidneys, liver, myocardium, pancreas, and brain. Routine histopathology and histochemistry identified fungal nephritis, hepatitis, myocarditis, pancreatitis, and encephalitis associated with intralesional fungal hyphae, frequently with fungal emboli and vasculitis. Pure cultures of C. albicans were obtained from fragments of the masses observed at the myocardium and kidneys, with the typical germ tube of C. albicans being identified by microscopic evaluation. A PCR assay that targeted the ITS1 and 4 generic regions of fungi, amplified the desired amplicon, and direct sequencing confirmed C. albicans. Immunohistochemical and molecular assays designed to identify common infectious disease pathogens of dogs did not confirm the participation of canine distemper virus, canine parvovirus, or canine adenovirus in the target tissues of this dog. These findings suggest that this dog suffered an initial cutaneous lesion, that probably served as portal of entry to the mammary gland, resulting in mammary candidiasis with subsequent embolic dissemination to multiple organs. This report represent the first description of mammary candidiasis in pet animals and probably one of the few pathological descriptions of mammary candidiasis in domestic animals. In this case, the cause of the fungal infection was probably associated with factors intrinsic to abdominal surgery, pregnancy, and the utilization of antibiotics.

Epidemiologic, Clinical and Immunological Consequences of Co-Infections during Canine Leishmaniosis

Simple Summary

Canine leishmaniosis (CanL), the most severe, visceralizing form of disease caused by Leishmania infantum transmitted by phlebotomine sand flies. CanL is frequently diagnosed in the Mediterranean basin and South America, although it is also found in other regions, including the United States (U.S.). Dogs in these regions are at risk for co-infections, prominently tick-borne diseases. Our review examines epidemiologic, clinical, and immunologic mechanisms found during the most common eight CanL co-infections reported in published literature. Co-infections alter immunologic processes and disease progression impacting CanL diagnosis, therapeutic responses, and prognosis.

Abstract

Canine leishmaniosis (CanL) is a vector-borne, parasitic disease. CanL is endemic in the Mediterranean basin and South America but also found in Northern Africa, Asia, and the U.S. Regions with both competent sand fly vectors and L. infantum parasites are also endemic for additional infectious diseases that could cause co-infections in dogs. Growing evidence indicates that co-infections can impact immunologic responses and thus the clinical course of both CanL and the comorbid disease(s). The aim for this review is to summarize epidemiologic, clinical, and immunologic factors contributing to eight primary co-infections reported with CanL: Ehrlichia spp., Anaplasma spp., Borrelia spp., Babesia spp., Trypanosoma cruzi, Toxoplasma gondii, Dirofilaria immitis, Paracoccidioides braziliensis. Co-infection causes mechanistic differences in immunity which can alter diagnostics, therapeutic management, and prognosis of dogs with CanL. More research is needed to further explore immunomodulation during CanL co-infection(s) and their clinical impact.

Updates in Paracoccidioides Biology and Genetic Advances in Fungus Manipulation

The dimorphic fungi of the Paracoccidioides genus are the causative agents of paracoccidioidomycosis (PCM). This disease is endemic in Latin America and primarily affects workers in rural areas. PCM is considered a neglected disease, despite being a disabling disease that has a notable impact on the public health system. Paracoccidioides spp. are thermally dimorphic fungi that present infective mycelia at 25 °C and differentiate into pathogenic yeast forms at 37 °C. This transition involves a series of morphological, structural, and metabolic changes which are essential for their survival inside hosts. As a pathogen, the fungus is subjected to several varieties of stress conditions, including the host immune response, which involves the production of reactive nitrogen and oxygen species, thermal stress due to temperature changes during the transition, pH alterations within phagolysosomes, and hypoxia inside granulomas. Over the years, studies focusing on understanding the establishment and development of PCM have been conducted with several limitations due to the low effectiveness of strategies for the genetic manipulation of Paracoccidioides spp. This review describes the most relevant biological features of Paracoccidioides spp., including aspects of the phylogeny, ecology, stress response, infection, and evasion mechanisms of the fungus. We also discuss the genetic aspects and difficulties of fungal manipulation, and, finally, describe the advances in molecular biology that may be employed in molecular research on this fungus in the future.

Diagnosis by molecular pathology of an early and atypical histoplasmosis lesion in the duodenum of an immunocompromised patient: A case report

Histoplasmosis is a fungal infection caused by Histoplasma capsulatum (HC), which can occasionally be aggressive resulting in the formation of granulomatous lesions. These are usually located in the lungs; however, immunocompromised patients may occasionally develop disseminated lesions in other organs as well. Human immunodeficiency virus (HIV) primarily infects cells of the immune system expressing CD4 molecules. Not only does HIV multiply within these cells, but it can also kill them or otherwise cause loss of cellular function, leading to an immunocompromised state. As a result, in an immunocompromised patient, infection with HC can have serious implications, often the development of visceral histoplasmosis in different organs. Although several types of lesions are formed in HC-infected organs, it may be difficult to distinguish the causative organism from other pathogens based on morphology alone. The present case report describes the case of a 57-year-old woman, from South America, who may have been infected with HC >20 years previously, remaining asymptomatic over the years. She later developed a lesion in the duodenum associated with immunodeficiency caused by HIV infection. The differential diagnosis of this case was made on the basis of several specific morphological findings using histopathological analysis and molecular pathological techniques. The pathogenesis of characteristic lesions caused by HC in the presence of HIV infection was also reviewed.

Diphtheric aspergillosis tracheitis with gastrointestinal dissemination secondary to viral infections in a dairy calf

Diphtheric aspergillosis tracheitis is an uncommon syndrome described in human pathology, usually associated with immunosuppression in the affected individuals. Interestingly, no comparative/equivalent cases were found in domestic animals. This report describes the pathological and mycological findings associated with diphtheric aspergillosis tracheitis in an immunocompromised calf. The main pathological findings were diphtheric tracheitis and rhinitis, and necrotizing ruminitis associated with intralesional septate, acute branching fungal hyphae consistent with Aspergillus spp. Mycological culture and isolation confirmed the fungal hyphae as A. fumigatus due to characteristic features. Immunohistochemistry (IHC) assays identified intralesional antigens of bovine viral diarrhea virus (BVDV) and malignant catarrhal fever virus (MCFV) at the trachea and small intestine; IHC detected intralesional antigens of bovine alphaherpesvirus 1 (BoHV-1) only at the trachea. These findings confirmed the simultaneous occurrence of A. fumigatus with concomitant infections due to BVDV, MCFV, and BoHV-1 in this calf. Since ovine gammaherpesvirus-2 (OvHV-2) is the cause of MCF in Brail, it is likely that the intralesional MCFV antigens identified were those of OvHV-2. In this case, disseminated aspergillosis was probably associated with the undeveloped immunological status of the calf that was further impaired due to the combined immunodepressive effects of BVDV and BoHV-1 infections. Although BVDV and BoHV-1 are infectious disease pathogens frequently associated with the development of bovine respiratory disease (BRD) in feedlot and dairy cattle, the identification of intralesional OvHV-2-like antigens in several parts of the lungs suggest that this MCFV also played a role in the BRD-associated lesions identified in this calf.

•

An unusual presentation of fungal diphtheric tracheitis associated with Aspergillus fumigatus is described in a dairy calf.

•

A Malignant Catarrhal Fever Virus, most likely, OvHV-2, was associated with the development of pneumonia in this calf.

•

Simultaneous infections in dairy calves may be more frequent than previously reported.

•

OvHV-2 should be considered as a possible disease pathogen associated with the development of bovine respiratory disease.

•

The immunodepressive effects of BVDV and BoHV-1 were fundamental for the development of the fungal disease observed in this calf.

Characterisation and outcome of idiopathic pyogranulomatous lymphadenitis in 64 English springer spaniel dogs

OBJECTIVES

To describe the history, clinicopathological abnormalities, diagnostic imaging findings, lymph node cytological/histological appearance, treatment and outcome of English springer spaniels diagnosed with idiopathic pyogranulomatous lymphadenitis.

MATERIALS AND METHODS

In this retrospective UK-based multicentre study, 64 dogs were recruited from 10 referral centres, 32 first-opinion practices and three histopathology/cytology laboratories, between 2010 and 2016.

RESULTS

The median age at presentation was 6 years (range: 0.17 to 11.75). Neutered females were frequently affected. Pyrexia (83.8%), peripheral lymphadenomegaly (78.4%), dermatological lesions (72.9%), lethargy (67.6%), hyporexia (54%), diarrhoea (29.7%), coughing (24.3%), epistaxis, sneezing or nasal discharge (21.6%), ocular signs (21.6%) and vomiting (16.2%) were reported in dogs for which the history and physical examination records were available. Popliteal (45.3%), superficial cervical (35.9%) and submandibular (37.5%) lymphadenomegaly were frequently reported. Haematology and serum biochemistry revealed non-specific changes. When undertaken, testing for infectious diseases was negative in all cases. Lymph node cytology, histopathology or both demonstrated mixed inflammatory (27%), pyogranulomatous (24%), neutrophilic (20%) or granulomatous (11%) lymphadenitis. Treatment details were available for 38 dogs, with 34 receiving prednisolone for a median duration of 15 weeks (range: 1 to 28 weeks). A good to excellent clinical response was reported in all but one case. Ten dogs relapsed after discontinuing prednisolone.

CLINICAL SIGNIFICANCE

Idiopathic pyogranulomatous lymphadenitis should be considered as a differential diagnosis for lymphadenopathy and pyrexia in English springer spaniels. The characteristics of the disease, absence of identifiable infectious aetiology and response to glucocorticoid therapy suggest an immune-mediated aetiology.

The Curious Case of "Case Report" of Infections Caused by Human and Animal Fungal Pathogens: An Educational Tool, an Online Archive, or a Format in Need of Retooling

Case reports describe the unusual occurrence and complications of diseases, diagnostic challenges, and notable therapeutic successes. Some journals have discontinued the case reports, while new case report journals have appeared in recent years. During the eightieth anniversary of Mycopathologia, it is fitting to examine the relevance of the case report since the journal continues to traverse the boundaries of basic and clinical sciences. A random sample of recent case reports and other articles were selected from Mycopathologia. Springer Nature individual article download statistics, and Google Scholar and Scopus citations numbers were compared to assess the reader access and bibliometric impact of case reports. Our analysis indicated that the case report format continues to be a vital element of publication in a cross-disciplinary journal such as Mycopathologia. Medical and veterinary case reports covering fungal pathogens are widely read as evident from their download numbers. The download numbers have a positive correlation with the completeness of the report, the topics and geographic origin of reports have a neutral influence, and the recency leads to lower downloads. There is no discernible trend between the download numbers and the citations of case reports as measured by Google Scholar and Scopus. A specially designed checklist for Mycopathologia case reports and new format MycopathologiaIMAGES are being introduced to improve the quality and relevance of case reports further.

Molecular detection of fungi of public health importance in wild animals from Southern Brazil

Some animals have an important relationship with fungal infections, and searching for pathogens in animal samples may be an opportunity for eco-epidemiological research. Since studies involving wildlife are generally restricted, using samples from road kills is an alternative. The aim of this study was to verify whether pathogenic fungi of public health importance occur in wildlife road kills from Santa Catarina State, Brazil. Organ samples (n = 1063) from 297 animals were analysed according to Polymerase Chain Reaction (PCR) using universal primers to detect fungi in general and, subsequently, using primers specific to Paracoccidioides brasiliensis, Histoplasma capsulatum and Cryptococcus spp. There were 102 samples positive for fungal species. Eight samples were positive for P. brasiliensis, three samples were positive for Cryptococcus spp. and one sample had coinfection by these two fungi. No sample was positive for Histoplasma spp. according to the molecular detection. Genetic sequencing allowed the identification of Fungal sp. in 89 samples, Cryptococcus neoformans in two samples and Aspergillus penicillioides in three samples. This study shows the importance of wild animals in the epidemiology of fungal infections and assists in the mapping of pathogen occurrence in a region that was not previously evaluated.

Serological Evidence of Infection by Paracoccidioides brasiliensis in Dogs with Leishmaniasis

Paracoccidioidomycosis is a systemic mycosis prevalent in Latin American countries, caused by the dimorphic fungi Paracoccidioides brasiliensis and P. lutzii. The habitat of these fungi in nature remains undefined, although it is believed that infection occurs by inhalation of infective propagules present in soil. Sentinel animals, such as dogs, can be valuable epidemiological markers of paracoccidioidomycosis. Taking into account that paracoccidioidomycosis and visceral leishmaniasis may occur in the same area, the objective of this study was to evaluate the occurrence of P. brasiliensis infection in dogs positive for Leishmania sp. Serum samples of dogs positive (n = 199) and negative (n = 101) for Leishmania sp. were analyzed by the immunodiffusion test using P. brasiliensis exoantigen, and 22 samples (7.3%) were positive. The serum samples positive in the immunodiffusion test were also analyzed by Western blotting using the P. brasiliensis gp43 recombinant protein, and 86% of the samples were positive. A high positive correlation (r = 0.96) between positivity for Leishmania sp. and P. brasiliensis was observed. These data suggest an association between leishmaniasis and paracoccidioidomycosis in dogs.