ajellomyces capsulatus is the holomorphic name for histoplasma capsulatum , the etiological agent of histoplasmosis , a systemic mycosis .
this thermo - dependent dimorphic fungus is soil - borne   and in organic nitrogen rich soils fungal growth and sporulation are accelerated .
therefore , places where bird and bat droppings enrich the soil with organic nitrogen , represent a potential environment for proliferation of the fungus and increases the risk of infection .
in this environment , the fungus exists in mycelial form , whereas in the host it exists as a yeast - like form .
commonly , exposure occurs when histoplasma spores become airborne and are inhaled , less frequently , ingestion and infection via open wounds can occur [ 4,810 ] . in its most severe form (
disseminated ) histoplasmosis can affect almost any part of the body ; which depends strongly on the genetic predisposition of the subject , according to recent experimental evidence
. severe clinical disease can result from high doses of infectious spores or if the infected host is immunocompromised ( 10 ) .
h. capsulatum is distributed worldwide   with certain evidence of its origin in latin america . despite this knowledge ,
there are still few reports published about histoplasmosis in domestic animals in this region [ 9,1315 ] , considering that it is common in latin america for domestic animals to live in backyards with poultry where the potential risk of infection is higher . here
, we report a case of histoplasmosis with multifocal lymphadenopathy , skin and gingival lesions in a dog that lived in close proximity to bird guano , used as fertilizer .
a 4-year - old female sterilized dog ( schnauzer ) presented initially mild gastrointestinal problems ( mucous diarrhea ) and respiratory affections ( sneezing ) , which were treated with oral hydration ( day 0 ) after veterinary evaluation . in day + 20 , the patient returned to the veterinary hospital because several dermatological problems appeared . these consisted of multiple crusted papules located over lips , back of head , neck , thorax and lumbar region ( fig .
furthermore , the dog presented swelling of submandibular and popliteal lymph nodes and left maxillary gingiva ( fig .
cytological examination using diff - quick staining method of a fine needle aspiration of papules and submandibular and popliteal lymph nodes , showed mixed cellularity represented by lymphocytes , plasma cells , neutrophils , eosinophils and epithelioid histiocytes in the background inflammatory component .
the latter contained numerous rounded to oval yeast - like structures in their cytoplasm , 24  m in diameter , surrounded by a thin clear halo and an eccentric purple core of crescent shape , compatible with h. capsulatum ( fig .
excisional biopsy of a skin nodule located in the dorsal neck was submitted for histopathology .
macroscopic examination revealed that the sample consisted of crusted papules composed of a well - defined , solid , yellow and firm granuloma ( fig .
microscopy showed a partially delimited non - encapsulated pyogranuloma inside the epidermis , dermis and adipose tissues ( fig . 2c ) .
the inflammatory cells were mainly comprised of neutrophils ( many degenerated ) , epithelioid macrophages ( some binucleated ) and a few reactive lymphocytes . inside the macrophages cytoplasm , numerous yeast - like structures ( 24  m in diameter ) were present , with shapes from round to oval , and surrounded by a clear thin halo , and an eccentric nucleus , compatible with yeast - like structures of h. capsulatum .
fungal samples obtained by fine needle aspiration of submandibular and popliteal lymph nodes were cultured in potato dextrose agar ( pda ) and brain heart agar ( bha)+5% human blood ; both media were supplemented with antibacterial agents , amoxicillin / clavulanate 5  g / ml , tobramycin 2  g / ml and chloramphenicol 5  g / ml . in order to obtain the filamentous form of the fungus and yeast - like structures , pda and bha plates were 28 days incubated at 25  c ( fig .
pda plates showed the filamentous form of the fungus and bha plates the yeast - like form , as expected .
microscopic structures of filamentous growth were examined with an optical microscope , the slide was prepared by placing a drop of methylene blue over the culture sample ( fig .
genomic dna of filamentous and yeast - like forms was extracted using the high pure pcr template preparation kit ( roche ) . the amplification and sequencing of the internal spacer ( its ) region was carried out with universal primers its1 ( 5-tccgtaggtgaacctgcgg-3  ) and its4 ( 5-tcctccgcttattgatatgc-3  ) .
the amplification protocol consisted of 1 cycle of initial denaturation for 5  min at 95  c , 30 cycles of denaturation for 1  min at 95  c , annealing for 30  s at 52  c , and extension for 1  min at 72  c , and a final extension for 5  min at 72  c .
the mz&zudla1 its sequence was analyzed using blast , then compared with previously described sequences via an upgma analysis ( geneious 5.6.4 .
after histochemical confirmation of initial diagnosis ( day + 33 ) , the treatment plan included cephalexin : 25  mg / kg taken orally every 12  h for 21 days , and ketoconazole : 10  mg / kg taken orally every 12  h for 60 days . during examination at day + 140 the dog exhibited a 95% skin lesion recovery ( fig .
it was unnecessary to proceed with further examinations due to the dog s full recovery and discharge .
during the first veterinary evaluation ( day 0 ) , the patient showed mild digestive and respiratory problems .
as these symptoms are not specific to histoplasmosis , the first diagnosis was missed . in the second medical evaluation ( day + 20 ) ,
the patient presented lymphadenopathy ( submandibular and popliteal ) , cutaneous and gingival lesions and thrombocytopenia .
it is known that disseminated histoplasmosis usually presents dermatological problems   and thrombocytopenia may be observed in up to half of dogs with histoplasmosis ( 10 ) ; thus , at the second examination there were signs indicating the disease .
furthermore , the data provided by the dog s owner revealed that they lived in the valley around quito where the weather is warm and humid , suitable conditions for h. capsulatum 
 . the owner also revealed that bird guano is used to fertilize her garden and , as reported previously , this material enhances the growth and sporulation of this fungus , suggesting that infection was via inhalation or ingestion of h. capsulatum spores .
results of cytological , histopathological and histochemical tests were compatible with disseminated histoplasmosis , due to the presence of intracellular yeast - like structures in lymph nodes and skin .
in addition to biochemical analyses , molecular tools provided important information about the pathogen genotype .
the its region has been used successfully in the identification of pathogenic and non - pathogenic fungal species . in our study
although itraconazole is the recommended treatment for histoplasmosis due to its effectiveness and lesser secondary effects , ketoconazole was used having the advantage of being less expensive , not nephrotoxic and excreted in low amounts by the kidneys   and proved just as effective in treatment . in conclusion ,
the current case report describes a case of histoplasmosis in a female canine diagnosed via cytology and culture of h. capsulatum from the lesions .
it is widely accepted that the use of itraconazole is the treatment of choice for histoplasmosis in dogs ; however , the use of ketoconazole , in this case , proved to be an adequate treatment option .
this sreport mainly helps veterinarians , but also doctors and researchers , to better understand the epidemiology , symptoms and laboratory diagnosis of this disease .
finally , we suggest that histoplasmosis should be considered for diagnosis in cases with mild symptoms , especially in areas with identified environmental risk factors .
 histoplasmosis is a zoonotic systemic mycosis caused by histoplasma capsulatum . 
 we report a case of a female canine , 4 years old , presenting multifocal lymphadenitis and skin and gingival lesions , in ecuador . based on cytological , histopathological , histochemical analyses , fungal culture and dna sequencing of the its region of the fungus 
 , the diagnosis confirmed the presence of h. capsulatum as the agent of infection . 
 the treatment plan included ketoconazole with a satisfactory outcome . 
Introduction
Case
Discussion
Conflict of interest