A latex cryptococcal antigen agglutination test for diagnosis and monitoring of therapy for cryptococcosis

SUMMARY: A latex cryptococcal antigen agglutination test (LCAT) was performed on sera obtained during the first 14 days of treatment from 58 animals (46 cats, 9 dogs, 2 koalas and 1 long billed corella) with cryptococcosis. The same commercial kit was used for all samples, and most serum samples were treated with pronase before testing. Sera from all 58 cases tested positive with the qualitative LCAT protocol (using undiluted sera), while sera from all 26 cats without cryptococcosis tested negative. Titres determined using the quantitative protocol ranged from 1 to 131 072 (median titre between 2048 and 4096), with 57 of 58 cases (including all 8 animals that presented for neurological signs) having titres 2 and thus considered positive according to the manufacturer's recommendations. The LCAT titre was positively correlated with disease severity (r = 0.4169; P = 0.0011), and patients with disseminated skin and/or lymph node involvement had significantly higher titres than those that did not (P = 0.0157). The presence of neurological signs, the species of the patient, concurrent viral disease (in cats) and the biotype of the isolate had no significant association with the LCAT titre. Cats that died of active cryptococcosis despite treatment did not have significantly higher titres (P = 0.3010) than those that responded to treatment. Sequential LCAT determinations obtained in 37 patients during treatment provided a useful quantitative indication of clinical progress, although the decline in titre lagged somewhat behind clinical improvement. Generally, the antigen titre declined by 2 to 4 fold per month during successful therapy. Although there are insufficent data to make unequivocal recommendations, we suggest that either antifungal therapy be continued until the LCAT titre declines to less than 1, or therapy be discontinued after a 32 fold or greater reduction in titre, with periodic monitoring of the serum antigen titre. Treatment of serum samples with pronase substantially increased the sensitivity of the LCAT.     

新生隐球菌病研究进展

隐球菌是条件致病性深部真菌,易发于细胞免疫功能受损的人群.新生隐球菌是隐球菌属的重要致病菌,属环境腐生菌,可从土壤和鸽粪中分离到,并被认为是人和动物最主要的传染源.医学方面,近年来由新生隐球菌引起的感染有逐渐增多的趋势,主要引起人的脑膜炎和肺炎.动物医学方面,可引起马的呼吸道病、牛羊的乳腺炎.鸽是隐球菌的自然宿主,但并不引起发病.该文从隐球菌病的病原特征、分类、毒力因子、致病性等生物学特性进行了概述,并对人和动物新生隐球菌病的传染和流行的基本环节、发病机制、临床表现、防治等方面的研究进展进行了综述.     

Feline cryptococcosis: a review and seven case reports

Systemic infection of the cat with the yeast-like fungus, Cryptococcus neoformans , is reviewed. Seven cases of the disease are reported, two of which were treated unsuccessfully with the anti-fungal agent, amphotericin B.     

Cryptococcosis in captive cheetah (Acinonyx jubatus): two cases

Cryptococcus neoformans is a yeast-like organism associated with pulmonary, meningoencephalitic, or systemic disease. This case report documents 2 cases of cryptococcosis with central nervous system involvement in captive cheetah (Acinonyx jubatus). In both cases the predominant post mortal lesions were pulmonary cryptococcomas and extensive meningoencephalomyelitis. Both cheetahs tested negative for feline immunodeficiency virus and feline leukaemia virus. The organism isolated in Case 2 was classified as Cryptococcus neoformans var. gattii, which is mainly associated with disease in immunocompetent hosts.     

Cryptococcosis in seven horses

The clinical, radiographic and post-mortem findings in 6 horses with cryptococcal pneumonia and one horse with an abdominal cryptococcal granuloma are described. In pulmonary cryptococcosis, the lesions were either diffuse and multiple, with bilateral lung involvement, or localised mainly to the dorsocaudal region of one lung. The cases of diffuse multiple cryptococcosis were thought to be associated with haematogenous spread of the fungus after gastrointestinal infection and dissemination from regional lymph nodes. The localised form of the disease was thought to have been associated with inhalation of cryptococci. In all cases of pulmonary cryptococcosis, encapsulated yeast-like organisms were demonstrated in Wright's-stained sediment of tracheal washes. In the horse with the abdominal granuloma, cryptococci were present in a fine needle aspirate sample. Isolates of Cryptococcus neoformans var gattii were recovered from 2 of the 5 horses in which cultures were attempted. In addition to a history of previous illness that may have predisposed to infection, most horses in this report had been in areas in which Eucalyptus camaldulensis, or the closely related E rudis, were growing. In humans, an epidemiological relationship between E camaldulensis and infection with C neoformans var gattii has been suggested. Cases of equine cryptococcosis carry a poor prognosis and treatment was not attempted in any of these cases.     

CRYPTOCOCCOSIS IN DOGS: A REPORT ON 6 CASES

The main features of Cryptococcus neoformans infection in 6 dogs, all of which were of large breed, were central nervous system involvement in all cases and diversity of the initial presenting signs. The respiratory tract was affected in one case, but the bronchopneumonia did not appear to be of cryptococcal origin. Immunosuppressive factors and other diseases which are believed to increase the susceptibility of man and animals to cryptococcal infection did not appear to be of importance in these cases.     

Inflammatory cerebrospinal fluid analysis in cats: clinical diagnosis and outcome

The medical records of 62 cats with clinical signs of central nervous system disease and accompanying inflammatory cerebrospinal fluid (CSF) analysis were examined retrospectively to determine if signalment, clinical signs, CSF analysis and ancillary testing could accurately predict the type of central nervous system disease that was present. An inflammatory CSF was defined as one in which a total nucleated cell count was greater than 5 cells/microl or one in which the total nucleated cell count was normal but the nucleated cell differential count was abnormal. Sex, degree of CSF inflammation, neuroanatomical location and systemic signs provided little contributory information to the final diagnosis. In 63% of the cases a presumptive diagnosis could be made based on a combination of clinical signs, clinicopathological data and ancillary diagnostic tests. CSF analysis alone was useful only in the diagnosis of cats with feline infectious peritonitis, Cryptococcus species infection, lymphoma and trauma. Overall, despite extensive diagnostic evaluation, a specific diagnosis could not be made in 37% of cats. The prognosis for cats with inflammatory CSF was poor with 77% of cats surviving less than 1 year.     

Systemic Cryptococcus albidus infection in a Doberman Pinscher.

Cryptococcus albidus is a saprophytic, encapsulated yeast usually found in air, both outdoor and indoor, and sometimes on human skin. It is not usually considered to be a primary pathogen. Most cryptococcal infections of humans and animals are caused by Cryptococcus neoformans. Several cases of C. albidus infection have been reported in humans over the past 20 years. In the veterinary literature, 2 equine cases have been described: genital infection and mycotic keratitis. The present report is the first documented case of C. albidus systemic infection in a dog. Veterinarians and diagnosticians should be aware that C. albidus may be a potential canine pathogen.     

Nasopharyngeal cryptococcosis

Naturally occurring cryptococcosis in five cats, a dog and a koala is described. Involvement of the nasopharynx was documented in all patients, and nasopharyngeal mass lesions accounted for the major presenting complaints in four. Signs referable to nasopharyngeal disease included snoring, stertor, inspiratory dyspnoea and aerophagia. Diagnoses were made by caudal rhinoscopy using a retroverted flexible endoscope, vigorous orthograde flushing with saline, or at necropsy. Concurrent cryptococcal rhinitis was present in all cases, although involvement appeared limited to the caudal nasal cavity in most cases. Typical signs of nasal cavity disease, such as sneezing and nasal discharge, were often absent. Treatment of nasopharyngeal cryptococcosis should include physical dislodgement or debulking of lesion(s) to provide immediate alleviation of upper airway obstruction, followed by systemic antifungal therapy to eliminate residual infection from the nasal cavity. Infections caused by Cryptococcus neoformans var gattii accounted for a disproportionately large number of these cases.     

Decreased Serum Lecithin:Cholesterol Acyltransferase Activity in Spontaneous Cases of Fatty Liver in Cows

Nakagawa, H., Oikawa, S., Oohashi, T. and Katoh, N., 1997. Decreased serum lecithin:cholesterol acyltransferase activity in spontaneous cases of fatty liver in cows. Veterinary Research Communications, 21 (1), 1-8. Lecithin:cholesterol acyltransferase (LCAT) activity in serum was evaluated in spontaneous cases of fatty liver in cows. The enzyme activity of 631 ± 62 U (mean ± SEM, decrease in nmol of free cholesterol per h per ml of serum) in cows with fatty liver (n = 16) was significantly (p < 0.01) lower than that in cows without fatty liver (979 ± 22 U; n = 16). In addition to the decrease in LCAT activity, the concentrations of phosphatidylcholine (a fatty aryl donor for esterification of free cholesterol) and of cholesteryl esters (products of the LCAT reaction) were reduced in the high-density lipoprotein fractions from cows with fatty livers. The concentration in the serum of apolipoprotein A-I, an activator of LCAT, was also reduced in cows with fatty livers. These results suggest that the decreased LCAT activity, which may be attributable to impaired hepatic secretion or to the suppression of the activity in the plasma by reduced concentrations of phosphatidylcholine and apolipoprotein A-I, resulted in the lower concentrations of cholesteryl esters. Because cholesteryl esters are utilized in steroidogenic tissues for the synthesis of steroid hormones such as progesterone and glucocorticoids, an insufficient supply of the cholesterols may be of relevance to the reduced fertility and immune competence observed in cows with fatty livers.     

Reduction in Serum Lecithin:Cholesterol Acyltransferase Activity in Natural Cases of Pneumonia in Calves

In experimental calf pneumonia induced by inoculations of Pasteurella haemolytica or bovine herpesvirus-1, lipoprotein lipid concentrations and lecithin:cholesterol acyltransferase (LCAT) activity decrease. The purpose of this study was to examine whether similar changes in lipoproteins occur in natural cases of calf pneumonia. When monitored in a time-course study, the activity of LCAT, and the concentrations of free cholesterol, cholesteryl esters, phospholipids and triglycerides were steadily decreased. No significant decreases in LCAT activity or lipid concentrations were detected in sera from cows with mastitis. These results, coupled with the previous findings on experimental calf pneumonia, indicate that, while decreases in LCAT activity and the LCAT-related lipid concentrations are involved in the pathogenesis of calf pneumonia, this is not the case for all inflammatory diseases.     

Cryptococcosis in ferrets: a diverse spectrum of clinical disease

Cryptococcosis was diagnosed in seven ferrets (five from Australia; two from western Canada) displaying a wide range of clinical signs. Two of the ferrets lived together. One (5-years-old) had cryptococcal rhinitis and presented when the infection spread to the nasal bridge. Its sibling developed cryptococcal abscessation of the right retropharyngeal lymph node 12 months later, soon after developing a severe skin condition. DNA fingerprinting and microsatellite analysis demonstrated that the two strains isolated from these siblings were indistinguishable. Two ferrets (2- to 3-years-old) developed generalised cryptococcosis: one had primary lower respiratory tract disease with pneumonia, pleurisy and mediastinal lymph node involvement, while in the other a segment of intestine was the primary focus of infection with subsequent spread to mesenteric lymph nodes, liver and lung. The remaining three ferrets (1.75 to 4-years-old) had localised disease of a distal limb, in one case with spread to the regional lymph node. Cryptococcus bacillisporus (formerly C. neoformans var gattii) accounted for three of the four infections in Australian ferrets where the biotype could be determined. The Australian ferret with intestinal involvement and the two ferrets from Vancouver had C. neoformans var grubii infections.     

Cryptococcus neoformans granuloma in the lung and spinal cord of a free-ranging cheetah (Acinonyx jubatus). A clinical report and literature review

A 6-year-old, male, wild-born, free-ranging cheetah (Acinonyx jubatus) was evaluated for acute onset of progressive lameness in the right hind limb. Survey radiographs were unrewarding and myelography indicated an intramedullary compressive mass at the L3-L4 region. A fine needle aspirate of the lesion indicated the presence of Cryptococcus organisms. Necropsy confirmed the presence of granulomas (cryptococcoma) in the lung and the spinal cord (meningomyelitis) caused by Cryptococcus neoformans var. gattii. Cryptococcus neoformans is a yeast-like organism that is a potential pathogen to many species. Initial infection is thought to be of respiratory origin and then it commonly disseminates systemically from the nasal cavity or lungs to the skin, eyes and central nervous system in particular. The cheetah tested negative for both feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV), as have all the previously reported cheetah cases. C. neoformans is a non-contagious, opportunistic organism and is the most common systemic mycoses in domestic cats and the cheetah.     

Feline pyothorax: a retrospective study of 27 cases in Australia

Pyothorax was diagnosed in 27 cats between 1983 and 2002. In 21 (78%) of the cases, pleural fluid culture and/or cytology was consistent with a mixed anaerobic bacterial infection of oropharyngeal origin. In six cases (22%), infection was caused by unusual pathogens or pathogens of non-oropharyngeal origin, including a Mycoplasma species, Cryptococcus gattii, Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. The overall mortality rate was 22%. Treatment was successful in 18 of 19 cases (95%) where closed thoracostomy tubes were inserted. One case resolved only after thoracotomy. Actinomyces species were isolated in three cases and in contrast to dogs where thoracotomy is recommended, they were resolved with tube thoracostomy. Mechanical complications occurred in 58% of the cats with indwelling chest tubes. Probable mechanisms of pleural space infection were identified in 18 cats (67%) including haematogenous infection (n=1), direct inoculation of bacteria into the pleural space (n=1), intrathoracic oesophageal rupture (n=1) and parapneumonic extension of infection (n=15; 56%). Of the latter, perioperative aspiration was suspected in two cats, parasitic migration in two and antecedent upper respiratory tract infection was implicated in seven. Parapneumonic spread of infection after colonisation and invasion of lung tissue by oropharyngeal flora appears to be the most frequent cause of feline anaerobic polymicrobial pyothorax and contests the widespread belief that direct inoculation of pleural cavity by bite wounds is more common.     

Reduced serum lecithin:cholesterol acyltransferase activity and cholesteryl ester concentration in calves experimentally inoculated with Pasteurella haemolytica and bovine herpes virus-1

Lecithin:cholesterol acyltransferase (LCAT), the enzyme responsible for esterification of cholesterol in plasma, is reported to be implicated in the regulation of inflammation in laboratory animals. The purpose of the present study was to elucidate the possible relevance of LCAT in the pathogenesis of calf pneumonia induced by inoculations of Pasteurella haemolytica and bovine herpes virus-1 into the calf lung. Serum LCAT activity was significantly (P < 0.01) reduced in calves inoculated with Pasteurella haemolytica. The concentration of cholesteryl esters (CE), the product of the LCAT reaction, was also decreased in the inoculated group. Decreases in LCAT activity and the CE concentration were similarly observed in calves in which bovine herpes virus-1 was inoculated. In both bacteria- and virus-inoculated calves, CE concentrations in the high-density lipoprotein fractions were distinctly decreased, whereas those in the low-density lipoprotein fractions were practically unaltered. The acute-phase proteins haptoglobin and serum amyloid A were detected in sera from the bacteria- and virus-inoculated calves; however, the two acute-phase proteins were also found in sera from the control calves. These results suggest that decreases in LCAT activity and the CE concentration are involved in the pathogenesis of pneumonia induced by inoculation of calves with Pasteurella haemolytica and bovine herpes virus-1, and also that the change in the LCAT system is more intimately related to the occurrence of calf pneumonia than the induction of acute-phase proteins such as haptoglobin.     

Use of terbinafine in the treatment protocol of intestinal Cryptococcus neoformans in a dog

A 2.5 yr old sexually intact male vizsla was admitted to the Iowa State University Veterinary Teaching Hospital for persistent diarrhea, weight loss, and panhypoproteinemia. Examination revealed an emaciated condition and melena. Two masses were palpated in the cranial abdomen. Hematology and serum biochemistry exhibited a regenerative anemia and confirmed the presence of panhypoproteinemia, suggestive of a protein-losing eneteropathy. Distinct areas of thickened intestinal wall and enlarged mesenteric lymph nodes were found on abdominal ultrasound. Cytology from those nodes showed the presence of suspected Cryptococcus spp., and infection was confirmed utilizing a cryptococcal antigen titer. Medical therapy with lipid-complexed amphotericin B and fluconazole was unsuccessful. Two surgical procedures were performed to remove the affected areas of intestine and lymph nodes, but the disease persisted as evidenced by a persistently elevated cryptococcal antigen titer. Terbinafine was prescribed, which resulted in complete resolution of clinical signs and a steadily decreasing cryptococcal antigen titer. Very few cases of intestinal cryptococcosis have been reported. In this case, infection resulted in a protein-losing enteropathy. In addition, this article describes the use of terbinafine in the treatment of intestinal cryptococcal infection in the dog, which has not been previously reported.     

A retrospective analysis of feline bronchoalveolar lavage cytology and microbiology (1995-2000)

A retrospective study of 88 bronchoalveolar lavage specimens from 80 cats presenting to the University of Sydney Veterinary Centre between 1995 and 2000 was performed. Bronchoalveolar lavage cytology and microbiology in conjunction with other diagnostic aids and patient records were used to classify cases as lower respiratory tract infections (LTRIs), LRTI revisits, feline bronchial disease, cardiac disease, neoplastic disease and multisystemic disease. Cases for which a definitive diagnosis could not be made were classified as inconclusive. Infectious agents identified were Mycoplasma spp., Pasteurella spp., Bordetella bronchiseptica, Salmonella typhimurium, Pseudomonas sp., Cryptococcus neoformans, Aelurostrongylus abstrusus and Eucoleus aerophilus. The study highlights the importance of bronchoalveolar lavage cytology and microbiology in the evaluation of feline lower respiratory tract disease.     

犬隐球菌病病原分离与ITS区序列分析鉴定

为确定引起格力犬皮肤病发生的病原菌种属并提供科学的诊治方案,从病犬发病部位真皮层刮取病料,采用沙氏培养基对病料进行分离、培养,根据菌落形态特征与镜检结果对分离到的病原菌进行初步鉴定。采用真菌鉴定通用引物ITS1及ITS4对分离菌的ITS区序列进行PCR扩增、测序,将测序结果与GenBank中的新生隐球菌进行比对分析并构建系统发育树。结果表明,分离到的病原菌经形态学鉴定初步判定为隐球菌属真菌,其ITS区序列与GenBank中的新生隐球菌（JN939462.1和JN939461.1）的ITS序列相似性为99%,且在系统发育树上属同一分支,提示引起该犬隐球菌病的病原菌为隐球菌属新生隐球菌。