Isolation of Cokeromyces recurvatus, initially misidentified as Coccidioides immitis, from peritoneal fluid in a cat with jejunal perforation

Cokeromyces recurvatus, a zygomycete, was isolated by fungal culture from the peritoneal fluid of a cat with jejunal perforation secondary to intestinal lymphosarcoma. This organism has not been recovered previously from a veterinary patient. The tissue form of C. recurvatus is morphologically similar to those of Coccidioides immitis and Paracoccidioides brasiliensis and may be misdiagnosed as 1 of these organisms on the basis of cytologic or histopathologic specimens, particularly in geographic regions where these organisms are not endemic.

Coccidioidomycosis: A Diagnostic Challenge

Coccidioidomycosis is a systemic fungal infection acquired endemically in the southwestern United States. Clinical disease is quite common in the dog; though less frequently recognized in the cat, disease is often severe at the time of diagnosis. Diagnosis can be a challenge because serology, while specific, is not very sensitive and quantitative titration of antibodies does not correlate entirely with clinical disease in dogs. Radiographs, serum biochemistry tests and complete blood counts are beneficial additions to the database when establishing a diagnosis; cytology, histopathology, and culture are definitive when available. Advanced imaging can detect central nervous system and subtle skeletal lesions. Disease can occur in most organs of the body and may prove a diagnostic challenge requiring several modalities. Coccidioidomycosis may need to be considered both in animals in the endemic region and in those with a travel history through it.

Fungal Infections of the Central Nervous System in the Dog and Cat

Fungal infections of the central nervous system (CNS) in dogs and cats are uncommon. The purpose of this paper is to review the clinical signs, diagnostic tests, and therapeutic options of fungal infections of the CNS in the dog and cat. Clinical signs are dependent on lesion location and are often multifocal. Extraneural involvement is common. Antemortem diagnosis can be difficult and is definitively made via cytology, biopsy, or culture of an affected organ or cerebrospinal fluid (CSF). Magnetic resonance imaging can support a diagnosis and may assist in therapeutic decisions. Fungal serology can support a diagnosis when direct visualization of the organism is not possible. Long-term azole maintenance therapy is suggested to enhance survival and prevent relapse. Serial cerebrospinal fluid evaluation and magnetic resonance imaging may identify early relapse.

Posaconazole therapy for systemic coccidioidomycosis in a chimpanzee (Pan troglodytes): a case report

Systemic coccidioidomycosis was diagnosed in a 4-year-old male chimpanzee (Pan troglodytes) with ascites and failure to thrive. Physical examination, laboratory and radiological studies, and exploratory laparotomy showed signs of systemic fungal infection that included penetration into the central nervous system (CNS). Serum and cerebrospinal fluid (CSF) titres, along with ascites cytology findings, confirmed the presence of Coccidioides immitis. However, the organism could not be cultured from the CSF. Treatment with fluconazole 10 mg kg(-1) daily for 6 months was not associated with clinical improvement. Subsequent treatment with posaconazole 50 mg kg(-1) daily for approximately 24 months resulted in negative serum titres and improved clinical status. Illness not directly related to the C. immitis infection caused the chimpanzee's deterioration and eventual killing. Histological examination performed during necropsy provided no evidence of coccidioidomycosis; however, a positive C. immitis serum antibody titre was noted. The successful suppression of coccidioidomycosis observed in this chimpanzee suggests that posaconazole may have a role in the treatment of CNS infections caused by susceptible fungi.

Subtotal pericardectomy and epicardial excision for treatment of coccidioidomycosis-induced effusive-constrictive pericarditis in dogs: 17 cases (1999-2003)

OBJECTIVE

To determine the history, clinicopathologic findings, and results of surgery for effusive-constrictive pericarditis associated with Coccidioides immitis infection in dogs.

DESIGN

Retrospective study.

ANIMALS

17 client-owned dogs that underwent a subtotal pericardectomy and epicardial excision.

PROCEDURE

Hospital records from May 1999 to June 2003 were reviewed. Data collected included history, clinicopathologic findings, treatments, and outcome. Follow-up information was obtained via recheck examination and by use of standardized telephone interviews with referring veterinarians and owners.

RESULTS

All dogs were of large breeds, and most were male (mean age, 4.66 years). Ten dogs had no prior history of C. immitis infection, and 7 dogs had chronic infection with C. immitis. Having a chronic C. immitis infection reduced the odds of survival, compared with no previous infection. All dogs had clinical signs of right-sided heart failure. All dogs had serum titers (range, 1:8 to 1:256) for antibodies against C. immitis prior to surgery, and titers were not significantly associated with outcome. Predominant echocardiographic findings were thickened pericardium, reduced right ventricular filling, and pleural or pericardial effusion. All dogs underwent a subtotal pericardectomy and epicardial excision and had fibrosing pyogranulomatous pericarditis in biopsy specimens obtained during surgery. The perioperative mortality rate was 23.5%, and the 2-year postdischarge survival rate was 82%.

CONCLUSIONS AND CLINICAL RELEVANCE

Surgical treatment via subtotal pericardectomy and epicardial excision is successful at relieving right-sided heart failure in dogs with effusive-constrictive pericarditis secondary to C. immitis infection, but long-term treatment with antifungal agents may still be required.

Incidence of coccidioides infection among dogs residing in a region in which the organism is endemic

OBJECTIVE

To determine the incidence of Coccidioides infection among dogs residing in a region in which the organism is endemic (Pima and Maricopa counties, Arizona) and estimate the rate of clinical illness.

DESIGN

Community-based longitudinal and cross-sectional studies.

ANIMALS

124 healthy 4- to 6-month-old seronegative puppies (longitudinal study) and 381 4- to 18-month-old dogs with unknown serostatus (cross-sectional study).

PROCEDURE

Dogs in the longitudinal study were tested at 6-month intervals for at least 1 year for anticoccidioidal antibodies. Dogs that became ill were evaluated for coccidioidomycosis. Dogs in the cross-sectional study were tested for anticoccidioidal antibodies once, and clinical abnormalities were recorded.

RESULTS

28 of the 104 (27%) dogs that completed the longitudinal study developed anticoccidioidal antibodies. Thirty-two of the 381 (8%) dogs in the cross-sectional study had anticoccidioidal antibodies. Five seropositive dogs in the longitudinal study and 13 seropositive dogs in the cross-sectional study had clinical signs of disease. The remaining seropositive dogs were otherwise healthy and were classified as subclinically infected. Survival analysis indicated that the cumulative probability of infection by 2 years of age was 28%, and the cumulative probability of clinical infection by 2 years of age was 6%. Titers for clinically and subclinically infected dogs overlapped.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that young dogs living in the study area had a high likelihood of becoming infected with Coccidioides spp, but few developed clinical illness. Serologic testing alone was insufficient for a diagnosis of clinical disease because of the overlap in titers between clinically and subclinically infected dogs.

Risk factors associated with Coccidioides infection in dogs

OBJECTIVE

To evaluate potential risk factors for Coccidioides infection among dogs living in a region in which the organism is endemic (Pima and Maricopa counties, Arizona).

DESIGN

Community-based longitudinal and cross-sectional studies.

ANIMALS

104 healthy 4- to 6-month-old puppies (longitudinal study) and 381 4- to 18-month-old dogs with unknown serostatus (cross-sectional study).

PROCEDURE

Dogs in the longitudinal study were tested 3 times at 6-month intervals for anticoccidioidal antibodies; dogs in the cross-sectional study were tested only once. Owners of all dogs completed a questionnaire on potential environmental exposures.

RESULTS

In the longitudinal study, the relative risk of infection for dogs that were outdoors during the day was 4.9 times the risk for dogs that were kept indoors. Seropositive dogs in the cross-sectional study were 6.2 times as likely to have access to > 1 acre to roam as were seronegative dogs. Logistic regression analysis indicated that the odds of infection increased with age (odds ratio [OR], 1.1), amount of roaming space (OR, 2.4), and walking in the desert (OR, 2.2). Walking on sidewalks had a protective effect (OR, 0.4).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that in regions in which the organism is endemic, dogs that spend more time outdoors or have more land in which to roam are at greater risk of infection with Coccidioides spp.

Seroprevalence of antibodies against Coccidioides immitis in healthy horses

OBJECTIVE

To determine the seroprevalence of antibodies against Coccidioides immitis in healthy horses residing in an area in which the organism is endemic.

DESIGN

Prospective study.

ANIMALS

197 healthy horses (in which coccidioidomycosis had not been previously diagnosed) that resided in an area of Arizona in which coccidioidomycosis is endemic.

PROCEDURE

Of the horses evaluated at the Arizona Equine Medical and Surgical Center during a 6-month period, 197 with no clinical signs of coccidioidomycosis were randomly selected for inclusion in the study; sera were evaluated for IgM and IgG antibodies against C immitis via an immunodiffusion assay (IgG-positive samples were assessed quantitatively). Within 6 months, recheck titer evaluations were attempted for all seropositive horses.

RESULTS

Serum antibodies against C immitis were detected in 8 of 197 horses (seroprevalence, 4.06%). Results of serologic assays were positive for IgG antibodies and negative for IgM antibodies in 7 horses and positive for both IgG and IgM antibodies in 1 horse; reciprocal serum IgG antibody titers were low (none > 8). Follow-up serologic data were obtained from 5 horses; compared with initial findings, horses had become seronegative or titers were unchanged or decreased. Duration of residence in the area was significantly shorter for seropositive horses than for seronegative horses.

CONCLUSIONS AND CLINICAL RELEVANCE

Serum antibodies against C immitis may rarely be detected in healthy horses residing in an area in which the disease is endemic; any horse with a detectable serum antibody titer should be reevaluated after an interval of at least 3 weeks.

Draining skin lesion from a desert Poodle

A 16-month-old intact female Poodle in Arizona had a history of intermittent coughing of a few weeks duration. Coccidiomycosis antibody screening test results were negative for immunoglobulin (Ig) M, but were positive (1:64) for IgG. Fine needle aspiration specimens of a draining lesion on the right palmar front foot contained large numbers of neutrophils, many of which contained bacteria, and lower numbers of macrophages. A few small structures also were observed, 2-5 microm in diameter with thin, nonstaining capsules and small, round to oval densely aggregated, eccentric nuclei. Cytologic findings were consistent with septic pyogranulomatous inflammation with Coccidiodes immitis endospores. Fungal culture of a sample from the draining lesion yielded white growth with barrel-shaped arthroconidia. Identification of the organism as C immitis was confirmed by a commercial DNA probe test. Although coccidioidomycosis often is diagnosed by microscopic identification of C immitis spherules in cytologic specimens, in this case only endospores, which are released from mature spherules, were observed. In cases of suspected coccidiodomycosis, the unique morphology of endospores may be useful in making a cytologic diagnosis.

Coccidioidomycosis in Przewalski's horses (Equus przewalskii)

Coccidioidomycosis is a rare, often subclinical infection in domestic animals caused by the fungus Coccidioides immitis. Because of an apparent high incidence of coccidioidomycosis in Przewalski's horses (Equus przewalskii) housed at a single facility, necropsy records and biomaterials from animals that died between 1984 and 2000 were reviewed (n = 30, 15 males, 15 females). Coccidioidomycosis was the leading cause of death (33%) in this population with lesions in the lungs and tracheobronchial lymph nodes of all animals and variable involvement of the skeletal muscle, heart, kidney, liver, skin, brain, spinal cord, spleen, as well as other regional lymph nodes. At the time of death, affected horses tended to be younger than unaffected animals, were from multiple lineages, and males were over represented. During the same time period, no other exotic equids (n = 76) housed at the same facility were diagnosed with coccidioidomycosis, suggesting that environmental factors are not the sole cause of the high incidence in E. przewalskii. Numbers of the lymphocyte subsets (CD3, CD4, CD5, CD8, CD21+ cells) quantified by flow cytometry were similar between Przewalski's horses and domestic horses (Equus caballus). Although responses of lymphocyte blastogenesis assays were similar between Przewalski's (n = 5) and domestic horses (n = 5) in response to the T cell mitogen concanavalin A, lymphocytes from two of the Przewalski's horses failed to proliferate in response to Coccidioides. One of these horses had systemic disease and the second developed coccidioidomycosis 2 yr later. These results suggest that the immune system of some Przewalski's horses fails to respond appropriately to Coccidioides.

Update on canine and feline fungal diseases

Systemic fungal diseases cause significant morbidity and mortality in dogs and cats. Blastomycosis, histoplasmosis, coccidiomycosis, and cryptococcosis represent the four most common systemic fungal diseases. Young adult, large breed dogs generally are predisposed; cats usually do not have predictable predispositions. Intact cell-mediated immunity is essential to initial resistance to infection and response to treatment in animals. Several body systems can be affected. Diagnosis can be confirmed on the basis of clinical signs and demonstration of the causative organism. Serology is helpful with coccidiomycosis and cryptococcosis. Treatment is complicated by limited availability of fungicidal antimicrobials and the necessity of long-term treatment with expensive drugs.

Clinical, clinicopathologic, and radiographic findings in dogs with coccidioidomycosis: 24 cases (1995-2000)

OBJECTIVE

To determine clinical, clinicopathologic, and radiographic abnormalities in dogs with coccidioidomycosis.

DESIGN

Retrospective case series.

ANIMALS

24 dogs.

PROCEDURE

Clinical information and results of clinicopathologic testing were obtained from medical records. Thoracic radiographs were reviewed to characterize abnormalities.

RESULTS

Dogs ranged from 1 to 10 years old at the time of diagnosis, with 12 dogs being between 1 and 3 years old. Historical complaints included cough, lameness, signs of head or neck pain, and difficulty breathing. Mild anemia, neutrophilia, and monocytosis were common. All dogs had hypoalbuminemia, and 8 of 15 had hyperglobulinemia. Thoracic radiographs of 19 dogs were reviewed. Pulmonary infiltrates were seen in 13 dogs, with an interstitial pattern of infiltration being most common. Hilar lymphadenopathy was seen radiographically in 10 dogs. Serum from 20 dogs was tested for antibodies against Coccidioides immitis. One dog was positive for IgM antibodies, 5 were positive for IgM and IgG antibodies, and 14 were positive for IgG antibodies. Quantitative IgG titers measured in 14 dogs ranged from 1:2 to 1:128 (median and mode, 1:32). In 6 dogs, histologic examination of biopsy samples revealed fungal spherules ranging from 8 to 70 microm in diameter.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that in dogs, coccidioidomycosis may be associated with a wide spectrum of nonspecific respiratory and musculoskeletal abnormalities. The chronic nature of the disease makes diagnosis difficult, even in regions in which the organism is endemic.

Multicentric lymphoma and disseminated coccidioidomycosis in a dog

An 11-year-old, spayed female Alaskan malamute with a history of coccidioidal osteomyelitis was evaluated for inappetance and lethargy. Findings included generalized lymphadenopathy, pale mucous membranes, tachycardia, and labored breathing. Laboratory findings and radiographic imaging were consistent with generalized lymphoma and disseminated coccidioidomycosis. Treatment consisted of antibiotics, chemotherapeutic agents, and antifungals.

Pulmonary coccidioidomycosis in a neonatal foal

A 13-day-old foal with profound tachypnoea and respiratory distress was examined. Thoracic radiographs revealed a severe, diffuse miliary pattern, and the foal was markedly hypoxaemic. It failed to improve with empirical treatment, and was euthanased. Lesions associated with Coccidioides immitis infection were identified at postmortem examination, and were limited to the lower respiratory tract.

Coccidioides immitis isolated from armadillos (Dasypus novemcinctus) in the state of Piauí, northeast Brazil

Natural infection of armadillos with Coccidioides immitis was studied in the state of Piauí, northeast of Brazil, endemic for coccidioidomycosis. In 1998, 26 nine-banded armadillos (Dasypus novemcinctus) were captured in 4 different counties. The animals were sacrificed under deep anesthesia with ether. At necropsy fragments of spleen, liver, lungs and heart were homogenized and seeded onto Sabouraud dextrose agar with and without cycloheximide (BBL, USA). Part of each organ was also processed for histological examination. Suspected colonies of filamentous fungi observed after the second week of incubation at room temperature, exhibiting barrel-shaped arthroconidia alternating with empty spaces, were inoculated intraperitoneally into mice. Three armadillos proved to be infected with C. immitis. Mice inoculated with suspected colonies obtained from homogenized spleen of three and liver of two armadillos developed disseminated coccidioidomycosis and immature and mature spherules of C. immitis were disclosed in several organs. For the first time armadillos (D. novemcinctus) were found naturally infected with C. immitis, adding new data on the ecology and on a possible role of these ancestral mammals in the evolutionary life cycle of this fungus.

Constrictive pericarditis secondary to Coccidioides immitis infection in a dog

A 4-year-old castrated male mixed-breed dog with a history of coccidioidomycosis was referred for evaluation of abdominal and pleural effusion. Results of radiography, ultrasonography, cytologic evaluation of thoracic fluid, and serologic testing supported a diagnosis of constrictive pericarditis secondary to infection with Coccidioides immitis. Aggressive treatment for presumptive coccidioidomycosis was begun, but the dog's condition continued to deteriorate, and the dog was euthanatized. At necropsy, the pericardium was thicker than normal and fibrotic and adhered to the epicardium. Microscopically, the pericardium and 1 section of epicardium contained lymphoplasmacytic infiltrates with a few macrophages and neutrophils. Coccidioides immitis was cultured from pericardial fluid. A search of records from the Arizona Veterinary Diagnostic Laboratory for 1988 through 1998 revealed that of 46 dogs in which a diagnosis of coccidioidomycosis was confirmed at necropsy, 13 had involvement of the heart or pericardium.

Canine systemic fungal infections

The principal route of infection for the disseminated fungal diseases discussed in this article is inhalation. In some cases, direct wound contamination and ingestion may also have an important role in the pathogenesis of the disease, especially in histoplasmosis. Another common theme of these diseases is the response of the immune system. If the inoculum is small and the animal is not immunocompromised, the infection may be limited to the respiratory tract and may resolve with few or no clinical signs. Dogs are usually presented to the veterinarian when the fungus has disseminated throughout the body via the circulatory or lymphatic systems, thus causing clinical signs secondary to specific organ infection. Draining skin tracts and lymphadenopathy occur in several of the diseases. The ocular location that is frequently affected is the choroid, where the organisms cause cell-mediated chorioretinitis. Early detection of these changes is important for saving vision and for diagnosing the systemic nature of the disease. Treatment is often effective, especially early in the disease, although it is expensive and long-term, with many animals needing over a year of treatment. Sometimes the treatment must continue lifelong. Ocular disease may not respond to treatment even when respiratory and other organ system clinical signs are rapidly improving. This isolation of the eye is similar to that of the CNS and requires regular monitoring of ocular disease, especially in the fundus, to ensure that systemic drugs are penetrating into the eye. Once the disease progresses to the anterior segment, the ocular prognosis worsens. Better penetration of the blood-retinal and blood-aqueous barriers may be achieved with fluconazole when compared with the other antifungal drugs. Secondary inflammatory ocular disease must also be monitored and treated appropriately to prevent scarring, which may cause vision loss or glaucoma.

Feline systemic fungal infections

Systemic fungal diseases are important diagnostic considerations in all sick cats, particularly in cats with ocular symptoms. The most common ocular manifestation of these diseases is posterior uveitis (choroiditis); however, anterior uveitis is sometimes present and is usually secondary to the inflammation in the posterior segment. Occasionally, adnexal diseases such as blepharitis, inflammation of the nictitating membrane, and ocular discharge may be present in cats with systemic mycoses. The prognosis for cats with systemic fungal diseases has changed with the advent of the triazole antifungal drugs. In the past, the prognosis was guarded to poor for survival of the cat. Today, with prolonged antifungal therapy, many cats recover completely from their disease. The prognosis for return of vision for eyes affected with systemic fungal disease is still guarded. Often, even if the infection is controlled systemically, the retina is severely damaged and may remain nonfunctional.

Peritoneal coccidioidomycosis in a mountain lion in California

An adult mountain lion (Felis concolor) from the vicinity of Weldon, California (USA) was necropsied following euthanasia due to emaciation and proximity to semi-rural housing. There were spherules consistent with Coccidioides immitis within peritoneal surfaces with granulomatous inflammation and fungi consistent with C. immitis were cultured from abdominal fluid. This is the first reported case of coccidioidomycosis in a wild mountain lion.

Inflammatory diseases of the central nervous system in dogs

Inflammatory diseases of the central nervous system (CNS) are important causes of seizures in dogs. Specific diseases include canine distemper, rabies, cryptococcosis, coccidioidomycosis, toxoplasmosis, neosporosis, Rocky Mountain spotted fever, ehrlichiosis, granulomatous meningoencephalomyelitis, and pug dog encephalitis. Inflammatory disorders should be considered when a dog with seizures has persistent neurological deficits, suffers an onset of seizures at less than 1 or greater than 5 years of age, or exhibits signs of systemic illness. A thorough history, examination, and analysis of cerebrospinal fluid are important in the diagnosis of inflammatory diseases. However, even with extensive diagnostic testing, a specific etiology is identified in less than two thirds of dogs with inflammatory diseases of the CNS.

Coccidioidomycosis in a bottlenose dolphin

A stranded bottlenose dolphin (Tursiops truncatus gilli) succumbed to a pulmonary infection of Coccidioides immitis. The dolphin initially presented with mild inspiratory dyspnea that rapidly worsened over 48 hr to include buoyancy abnormalities and finally death. At necropsy, caseous nodules were observed throughout the lungs and perihilar lymph nodes. On histological examination of tissues, double walled organisms containing endospores characteristic of C. immitis were observed in lung, perihilar lymph nodes, and brain. Pyogranulomatous infiltrates were observed in the lung and perihilar lymph nodes only. A DNA Gen-Probe test performed on a purified isolate confirmed infection by C. immitis. Serum was positive for antibodies to C. immitis at a titer of 1:128 and was negative for all known marine morbilliviruses. Although there have been reports of C. immitis infections in free ranging marine wildlife, including California sea lions (Zalophus californianus) and sea otters (Enhydra lutris), this is the first reported case of coccidioidomycosis in a cetacean.

Disseminated coccidioidomycosis in a mandrill baboon (Mandrillus sphinx): a case report

A case of disseminated coccidioidomycosis caused by a dimorphic fungus Coccidioides immitis in a mandrill baboon (Mandrillus sphinx) was diagnosed following radiography, ultrasound-guided aspiration of thoracic lesions, and aspiration cytology of skeletal lesions of the left sixth rib. The diagnosis was confirmed by fungal culture and serum quantitative immunodiffusion for antibodies against C. immitis.

Granulomatous meningitis caused by Coccidioides immitis in a dog

Granulomatous meningitis attributable to Coccidioides immitis was diagnosed on postmortem examination in a 4-year-old Border Collie. Clinical signs included CNS disease, aspiration pneumonia secondary to a megaesophagus, and otitis externa. Central nervous system signs included central vestibular and cranial nerve dysfunction. Cerebellar and medullary infiltrates seen on histologic examination affected cranial nerves VIII, IX, and X. Despite extensive diagnostics, diagnosis was not made antemortem. Analysis of CSF suggested suppurative meningitis, but bacteriologic culture results were negative. Coccidioides endospores were identified on reexamination of brain tissue. The clinical course of disease and rate of Coccidioides immitis infection is variable. Causative agents of granulomatous or inflammatory CNS disease may include fungal infection more often than is currently suspected.