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Prototheca zopfii Genotype 2-induced Nasal Dermatitis in a Cat
J. Comp. Path. 2015, Vol. 152, 287e290
Available online at www.sciencedirect.com
ScienceDirect www.elsevier.com/locate/jcpa
INFECTIOUS DISEASE
Prototheca zopfii Genotype 2-induced Nasal Dermatitis in a Cat N. Huth*, R. F. Wenkel†, N. Roschanski‡, U. R€ osler‡, L. Plaggex and S. Sch€ oniger* * Institute of Pathology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 33, Leipzig, † Veterinary Clinic for Small Animals Dr. Ralph Wenkel, Anhalter Straße 3, Halle/Saale, ‡ Institute for Animal Hygiene and Environmental Health, Free University Berlin, Robert-von-Ostertag-Straße 7-13, Berlin and x Institute of Virology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 29, Leipzig, Germany
Summary Few published cases of feline protothecosis exist; all of these were restricted to the skin and speciation of the causative organism revealed an infection with Prototheca wickerhamii in each case. This report describes Prototheca zopfii genotype 2-induced inflammation of the nasal skin and cutaneous mucosa of the right nostril in a 14-yearold neutered female domestic shorthair cat. Microscopical examination revealed marked pyogranulomatous inflammation with numerous intralesional algae. These had a round to ovoid shape, were 8e21 mm in diameter, formed endospores and displayed a positive immunoreaction for Prototheca zopfii antigen. By 18S rRNA gene amplification and sequencing the intralesional algae were confirmed as Prototheca zopfii and further characterized as Prototheca zopfii genotype 2. This case report reveals Prototheca zopfii as an additional Prototheca species associated with feline protothecosis. Ó 2015 Elsevier Ltd. All rights reserved. Keywords: cat; dermatitis; gene sequencing; Prototheca zopfii genotype 2
The genus Prototheca belongs to the achlorophyllous algae, which are unicellular organisms with an asexual reproductive cycle resulting in an irregular cleavage and the release of sporangiospores (Pal et al., 2014). Prototheca species are saprophytes with a worldwide distribution that have been isolated from plants, water and soil as well as the skin, respiratory tract and faeces of healthy human beings and domestic animals (Pore et al., 1983; Lass-Fl€orl and Mayr, 2007; Pal et al., 2014). The genus encompasses different species including the facultative pathogens Prototheca zopfii genotype 2, Prototheca wickerhamii and Prototheca blaschkeae (Roesler et al., 2006). In human beings and dogs protothecosis is rare and occurs sporadically (Lass-Fl€orl and Mayr, 2007; Pal et al., 2014). Three main forms of human protothecosis are recognized: cutaneous or disseminated infections Correspondence to: S. Sch€oniger (e-mail: Sandra.Schoeniger@vetmed. uni-leipzig.de). 0021-9975/$ - see front matter http://dx.doi.org/10.1016/j.jcpa.2015.02.001
and olecranon bursitis (Lass-Fl€orl and Mayr, 2007). In dogs, protothecosis is usually disseminated and often associated with primary colitis (Stenner et al., 2007; Pal et al., 2014), while an infection restricted to the skin is rare (Gross et al., 2005). In cattle, mastitis is the most frequently observed form of protothecosis (Ahrholdt et al., 2012). Protothecosis in human beings and dogs is either caused by Prototheca wickerhamii or Prototheca zopfii (Lass-Fl€orl and Mayr, 2007; Stenner et al., 2007). A genotypic analysis of Prototheca zopfii isolates from diseased human beings and dogs showed the presence of Prototheca zopfii genotype 2 (Ahrholdt et al., 2012). In more than 90% of the cases, Prototheca-induced bovine mastitis is evoked by Prototheca zopfii genotype 2 (M€oller et al., 2007; Marques et al., 2008; Ahrholdt et al., 2012). So far, only few cases of feline protothecosis have been published and all were cutaneous infections (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). In Ó 2015 Elsevier Ltd. All rights reserved.
288
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all but one of these cases (Finnie and Coloe, 1981) further speciation was performed and Prototheca wickerhamii was identified. To the best of our knowledge this is the first case report describing Prototheca zopfii genotype 2-associated nasal dermatitis in a cat. A 14-year-old neutered female domestic shorthair cat was presented with mild respiratory signs and nodular lesions (up to 0.5 cm diameter) of the skin of the nasal bridge and within the cutaneous mucosa of the right nostril. Reportedly, the non-pruritic cutaneous lesions were first noted approximately 1 year previously. The affected skin was mildly thickened, partially alopecic and covered by serohaemorrhagic crusts (Fig. 1). The alterations within the cutaneous mucosa caused mild stenosis of the right nostril, resulting in mild respiratory problems. The cat had no evidence of a systemic disease. Since the cat was difficult to handle, general anaesthesia was administered in order to undertake venipuncture, radiography of lungs and the head, rhinoscopy and the collection of biopsy samples of affected skin and cutaneous mucosa. Results of the haematological examination were unremarkable. Polymerase chain reaction (PCR) on blood samples for the detection of feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) was negative. Radiographs did not show alterations of the lungs or head. Rhinoscopy revealed a circumferential slightly elevated mass in the cutaneous mucosa of the right nostril. The biopsy samples, measuring up to 0.3 0.3 0.1 cm, were submitted fixed in 4% neutral buffered formalin for histopathological exam-
Fig. 1. The skin of the nasal bridge contains a few partially alopecic, crusted nodular lesions.
ination. The specimens were processed routinely, embedded in paraffin wax, sectioned (2 mm) and stained with haematoxylin and eosin (HE). In addition, Grocott, Gomori and Gridley stains as well as a periodic acideSchiff (PAS) reaction were performed. Microscopical examination revealed marked pyogranulomatous inflammation characterized by infiltration of the dermis and lamina propria of the nasal cutaneous mucosa with numerous epithelioid macrophages and small aggregates of neutrophils mixed with a few lymphocytes and plasma cells. Numerous intralesional infectious organisms were noted, which were located within the cytoplasm of epithelioid macrophages and extracellularly within the tissue (Fig. 2). These infectious agents were unicellular, round to oval in shape and measured 8e21 mm. They were surrounded by a 2e3 mm thick clear halo consistent with a cell wall, and their cytoplasm was slightly basophilic. Some displayed internal septations reflecting multiplication in the form of endosporulation. Others were degenerate, and in a few only, the collapsed outer capsule was preserved (Figs. 2 and 3). They were highlighted by Grocott, Gomori and Gridley stains (Fig. 3) as well as being PAS positive. Histomorphological features of these organisms were consistent with algae and an infection with a Prototheca species was considered most likely, since no green discolouration of affected tissues was observed grossly. In comparison, infection with the green alga Chlorella spp. commonly causes a green discolouration of affected tissues (Ramırez-Romero et al., 2010).
Fig. 2. The affected skin shows marked pyogranulomatous dermatitis characterized by infiltration with numerous epithelioid macrophages (black arrows) and fewer neutrophils (white arrows) with numerous intralesional infectious organisms consistent with algae (arrowheads). HE. Bar, 75 mm.
Protothecal Dermatitis in a Cat
Fig. 3. Intralesional infectious organisms measure 8e21 mm and are surrounded by a thick cell wall (arrowheads); some show internal septations (thin arrow), others are degenerate (thick arrow). Gridley stain. Bar, 50 mm.
To further characterize the intralesional infectious agents, immunohistochemistry (IHC) and molecular analysis were performed. For IHC, a polyclonal rabbit antiserum against Prototheca zopfii (Roesler et al., 2003), the peroxidase anti-peroxidase complex method and 3, 30 -diaminobenzidine tetrahydrochloride as chromogen were used. In addition, DNA was isolated from formalin-fixed and paraffin waxembedded tissue and four overlapping fragments of the 18S rRNA gene were amplified, using the previously described primer pairs Proto18-1, Proto18-2, Proto18-3 and Proto18-4, and sequenced (Roesler et al., 2006). The sequence data were compared with the 18S rRNA genes of the major Prototheca species using the Lasergene DNA software package 10 (DNAStar, Madison, Wisconsin, USA). Intralesional infectious agents were immunopositive for Prototheca zopfii antigen (Fig. 4). Molecular analysis confirmed an infection with Prototheca zopfii and further characterized the causative agent as Prototheca zopfii genotype 2. The histopathological findings together with the results of the IHC and molecular analysis were consistent with pyogranulomatous inflammation of the nasal skin and cutaneous mucosa of the right nostril caused by Prototheca zopfii genotype 2. Immediately after the microscopical diagnosis, treatment was initiated. The cat received ketoconazole (10 mg/kg) together with food twice a day for 20 days followed by the local application of terbinafine hydrochloride once a day for a further 6 weeks. The mucocutaneous lesions showed partial regression. Over the following 6 months, the cat progressively lost weight and finally showed seizure
289
activity. The owners elected for humane destruction, but a post-mortem examination was not permitted. Thus, it could not be determined if the Prototheca zopfii infection was restricted to the nasal area or had spread to other organs. To the authors’ knowledge, feline Prototheca zopfii genotype-2 induced disease has not been reported previously. In all five feline cases with speciation, Prototheca wickerhamii was identified (Kaplan et al., 1976; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). For characterization of the causative algae species, an immunofluorescent antibody (Kaplan et al., 1976) or biochemical methods (Kaplan et al., 1976; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010) were used. In the present case, however, a detailed molecular analysis was applied resulting in the identification of Prototheca zopfii genotype 2. The molecular characterization of Prototheca isolates will likely be beneficial for the identification of strain- or even genotype-specific treatment options in the future (Pal et al., 2014). Previously published cases of feline protothecosis were diagnosed in six adult cats aged 3e16 years; five of these were male and in one case the gender was unknown (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). Skin lesions of affected cats consisted of focal or multifocal (pyo) granulomatous dermatitis or cellulitis (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). The lesions measured 0.6 cme5 cm in diameter (Kaplan et al., 1976; Finnie and Coloe, 1981; Dillberger et al., 1988) and were located on the head, including the nasal area, ear and forehead, the distal limb and the
Fig. 4. Intralesional algae label positively for Prototheca zopfii antigen (arrowhead). IHC. Bar, 20 mm.
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290
tail (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). Reported locations together with the present case indicate that the head may be a predilection site for feline protothecosis. Prototheca-induced dermatitis in human beings and dogs as well as bovine Prototheca-caused mastitis is likely initiated by a traumatic inoculation or wound contamination by the algae (Pal et al. 2014). This was also considered the most likely route of infection in the present case. Immunosuppression predisposes to protothecosis in human beings (Lass-Fl€orl and Mayr, 2007) and has also been discussed as a possible influencing factor in dogs (Stenner et al., 2007). Despite the detection of numerous algae in all published cases of feline protothecosis (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010), evidence of an impaired immune defence existed only in one cat that had a marked leucopenia, but tested negative for infection with FeLV and FIV (Endo et al., 2010). In this case and the previously published cases, no evidence for a disseminated disease was detected (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). In one cat, however, there was involvement of the regional lymph node (Coloe and Allison, 1982). It has been postulated that certain Prototheca species and their subtypes may exist within a particular environmental niche (Blaschke-Hellmessen et al., 1985) and that they differ in regard to their virulence (Ahrholdt et al., 2012). The latter may explain the higher susceptibility of some domestic animals to infection with a particular Prototheca species or even genotypes. In conclusion, Protoheca zopfii genotype 2 has been identified as a pathogenic Prototheca species in cats and protothecosis should be included as a differential diagnosis for nodular (muco)cutaneous disease in this species.
References Ahrholdt J, Murugaiyan J, Straubinger RK, Jagielski T, Roesler U (2012) Epidemiological analysis of worldwide bovine, canine and human clinical Prototheca isolates by PCR genotyping and MALDI-TOF mass spectrometry proteomic phenotyping. Medical Mycology, 50, 234e243. Blaschke-Hellmessen R, Schuster H, Bergmann V (1985) Differenzierung von Varianten bei Prototheca zopfii Kr€ uger 1894. Archiv f€ur experimentelle Veterin€armedizin, 39, 387e397. Coloe PJ, Allison JF (1982) Protothecosis in a cat. Journal of the American Veterinary Medical Association, 180, 78e79.
Dillberger JE, Homer B, Daubert D, Altman NH (1988) Protothecosis in two cats. Journal of the American Veterinary Medical Association, 192, 1557e1559. Endo S, Sekiguchi M, Kishimoto Y, Kano R, Aoki S et al. (2010) The first case of feline Prototheca wickerhamii infection in Japan. Journal of Veterinary Medical Science, 72, 1351e1353. Finnie JW, Coloe PJ (1981) Cutaneous protothecosis in a cat. Australian Veterinary Journal, 57, 307e308. Gross TL, Ihrke PJ, Walder EJ, Affolter VK (2005) Infectious nodular and diffuse granulomatous and pyogranulomatous diseases of the skin. In: Skin Diseases of the Dog and Cat, 2nd Edit, TL Gross, PJ Ihrke, EJ Walder, VK Affolter, Eds., Blackwell Publishing, pp. 272e319. Kaplan W, Chandler FW, Holzinger EA, Plue RE, Dickinson O (1976) Protothecosis in a cat: first recorded case. Sabouraudia, 14, 281e286. Lass-Fl€ orl C, Mayr A (2007) Human protothecosis. Clinical Microbiology Reviews, 20, 230e242. Marques S, Silva E, Kraft C, Carvalheira J, Videira A et al. (2008) Bovine mastitis associated with Prototheca blaschkae. Journal of Clinical Microbiology, 46, 1941e1945. M€ oller A, Truyen U, Roesler U (2007) Prototheca zopfii genotype 2: the causative agent of bovine protothecal mastitis? Veterinary Microbiology, 120, 370e374. Pal M, Abraha A, Rahman MT, Dave P (2014) Protothecosis: an emerging algal disease of humans and animals. International Journal of Life Sciences, Biotechnology and Pharma Research, 3, 1e13. Pore RS, Barnett EA, Barnes WC, Walker JD, Walker JR (1983) Prototheca ecology. Mycopathologia, 81, 49e62. Ramırez-Romero R, Rodrıguez-Tovar LE, Nev arezGarza AM, L opez A (2010) Chlorella infection in a sheep in Mexico and minireview of published reports from humans and domestic animals. Mycopathologia, 169, 461e466. Roesler U, M€ oller A, Hensel A, Baumann D, Truyen U (2006) Diversity within the current algal species Prototheca zopfii: a proposal for two Prototheca zopfii genotypes and description of a novel species, Prototheca blaschkeae sp. nov. International Journal of Systematic and Evolutionary Microbiology, 56, 1419e1425. Roesler U, Scholz H, Hensel A (2003) Emended phenotypic characterization of Prototheca zopfii: a proposal for three biotypes and standards for their identification. International Journal of Systematic and Evolutionary Microbiology, 53, 1195e1199. Stenner VJ, Mackay B, King T, Barrs VR, Irwin P et al. (2007) Protothecosis in 17 Australian dogs and a review of the canine literature. Medical Mycology, 45, 249e266.
November 28th, 2014 ½ Received, Accepted, February 3rd, 2015
Available online at www.sciencedirect.com
ScienceDirect www.elsevier.com/locate/jcpa
INFECTIOUS DISEASE
Prototheca zopfii Genotype 2-induced Nasal Dermatitis in a Cat N. Huth*, R. F. Wenkel†, N. Roschanski‡, U. R€ osler‡, L. Plaggex and S. Sch€ oniger* * Institute of Pathology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 33, Leipzig, † Veterinary Clinic for Small Animals Dr. Ralph Wenkel, Anhalter Straße 3, Halle/Saale, ‡ Institute for Animal Hygiene and Environmental Health, Free University Berlin, Robert-von-Ostertag-Straße 7-13, Berlin and x Institute of Virology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 29, Leipzig, Germany
Summary Few published cases of feline protothecosis exist; all of these were restricted to the skin and speciation of the causative organism revealed an infection with Prototheca wickerhamii in each case. This report describes Prototheca zopfii genotype 2-induced inflammation of the nasal skin and cutaneous mucosa of the right nostril in a 14-yearold neutered female domestic shorthair cat. Microscopical examination revealed marked pyogranulomatous inflammation with numerous intralesional algae. These had a round to ovoid shape, were 8e21 mm in diameter, formed endospores and displayed a positive immunoreaction for Prototheca zopfii antigen. By 18S rRNA gene amplification and sequencing the intralesional algae were confirmed as Prototheca zopfii and further characterized as Prototheca zopfii genotype 2. This case report reveals Prototheca zopfii as an additional Prototheca species associated with feline protothecosis. Ó 2015 Elsevier Ltd. All rights reserved. Keywords: cat; dermatitis; gene sequencing; Prototheca zopfii genotype 2
The genus Prototheca belongs to the achlorophyllous algae, which are unicellular organisms with an asexual reproductive cycle resulting in an irregular cleavage and the release of sporangiospores (Pal et al., 2014). Prototheca species are saprophytes with a worldwide distribution that have been isolated from plants, water and soil as well as the skin, respiratory tract and faeces of healthy human beings and domestic animals (Pore et al., 1983; Lass-Fl€orl and Mayr, 2007; Pal et al., 2014). The genus encompasses different species including the facultative pathogens Prototheca zopfii genotype 2, Prototheca wickerhamii and Prototheca blaschkeae (Roesler et al., 2006). In human beings and dogs protothecosis is rare and occurs sporadically (Lass-Fl€orl and Mayr, 2007; Pal et al., 2014). Three main forms of human protothecosis are recognized: cutaneous or disseminated infections Correspondence to: S. Sch€oniger (e-mail: Sandra.Schoeniger@vetmed. uni-leipzig.de). 0021-9975/$ - see front matter http://dx.doi.org/10.1016/j.jcpa.2015.02.001
and olecranon bursitis (Lass-Fl€orl and Mayr, 2007). In dogs, protothecosis is usually disseminated and often associated with primary colitis (Stenner et al., 2007; Pal et al., 2014), while an infection restricted to the skin is rare (Gross et al., 2005). In cattle, mastitis is the most frequently observed form of protothecosis (Ahrholdt et al., 2012). Protothecosis in human beings and dogs is either caused by Prototheca wickerhamii or Prototheca zopfii (Lass-Fl€orl and Mayr, 2007; Stenner et al., 2007). A genotypic analysis of Prototheca zopfii isolates from diseased human beings and dogs showed the presence of Prototheca zopfii genotype 2 (Ahrholdt et al., 2012). In more than 90% of the cases, Prototheca-induced bovine mastitis is evoked by Prototheca zopfii genotype 2 (M€oller et al., 2007; Marques et al., 2008; Ahrholdt et al., 2012). So far, only few cases of feline protothecosis have been published and all were cutaneous infections (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). In Ó 2015 Elsevier Ltd. All rights reserved.
288
N. Huth et al.
all but one of these cases (Finnie and Coloe, 1981) further speciation was performed and Prototheca wickerhamii was identified. To the best of our knowledge this is the first case report describing Prototheca zopfii genotype 2-associated nasal dermatitis in a cat. A 14-year-old neutered female domestic shorthair cat was presented with mild respiratory signs and nodular lesions (up to 0.5 cm diameter) of the skin of the nasal bridge and within the cutaneous mucosa of the right nostril. Reportedly, the non-pruritic cutaneous lesions were first noted approximately 1 year previously. The affected skin was mildly thickened, partially alopecic and covered by serohaemorrhagic crusts (Fig. 1). The alterations within the cutaneous mucosa caused mild stenosis of the right nostril, resulting in mild respiratory problems. The cat had no evidence of a systemic disease. Since the cat was difficult to handle, general anaesthesia was administered in order to undertake venipuncture, radiography of lungs and the head, rhinoscopy and the collection of biopsy samples of affected skin and cutaneous mucosa. Results of the haematological examination were unremarkable. Polymerase chain reaction (PCR) on blood samples for the detection of feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) was negative. Radiographs did not show alterations of the lungs or head. Rhinoscopy revealed a circumferential slightly elevated mass in the cutaneous mucosa of the right nostril. The biopsy samples, measuring up to 0.3 0.3 0.1 cm, were submitted fixed in 4% neutral buffered formalin for histopathological exam-
Fig. 1. The skin of the nasal bridge contains a few partially alopecic, crusted nodular lesions.
ination. The specimens were processed routinely, embedded in paraffin wax, sectioned (2 mm) and stained with haematoxylin and eosin (HE). In addition, Grocott, Gomori and Gridley stains as well as a periodic acideSchiff (PAS) reaction were performed. Microscopical examination revealed marked pyogranulomatous inflammation characterized by infiltration of the dermis and lamina propria of the nasal cutaneous mucosa with numerous epithelioid macrophages and small aggregates of neutrophils mixed with a few lymphocytes and plasma cells. Numerous intralesional infectious organisms were noted, which were located within the cytoplasm of epithelioid macrophages and extracellularly within the tissue (Fig. 2). These infectious agents were unicellular, round to oval in shape and measured 8e21 mm. They were surrounded by a 2e3 mm thick clear halo consistent with a cell wall, and their cytoplasm was slightly basophilic. Some displayed internal septations reflecting multiplication in the form of endosporulation. Others were degenerate, and in a few only, the collapsed outer capsule was preserved (Figs. 2 and 3). They were highlighted by Grocott, Gomori and Gridley stains (Fig. 3) as well as being PAS positive. Histomorphological features of these organisms were consistent with algae and an infection with a Prototheca species was considered most likely, since no green discolouration of affected tissues was observed grossly. In comparison, infection with the green alga Chlorella spp. commonly causes a green discolouration of affected tissues (Ramırez-Romero et al., 2010).
Fig. 2. The affected skin shows marked pyogranulomatous dermatitis characterized by infiltration with numerous epithelioid macrophages (black arrows) and fewer neutrophils (white arrows) with numerous intralesional infectious organisms consistent with algae (arrowheads). HE. Bar, 75 mm.
Protothecal Dermatitis in a Cat
Fig. 3. Intralesional infectious organisms measure 8e21 mm and are surrounded by a thick cell wall (arrowheads); some show internal septations (thin arrow), others are degenerate (thick arrow). Gridley stain. Bar, 50 mm.
To further characterize the intralesional infectious agents, immunohistochemistry (IHC) and molecular analysis were performed. For IHC, a polyclonal rabbit antiserum against Prototheca zopfii (Roesler et al., 2003), the peroxidase anti-peroxidase complex method and 3, 30 -diaminobenzidine tetrahydrochloride as chromogen were used. In addition, DNA was isolated from formalin-fixed and paraffin waxembedded tissue and four overlapping fragments of the 18S rRNA gene were amplified, using the previously described primer pairs Proto18-1, Proto18-2, Proto18-3 and Proto18-4, and sequenced (Roesler et al., 2006). The sequence data were compared with the 18S rRNA genes of the major Prototheca species using the Lasergene DNA software package 10 (DNAStar, Madison, Wisconsin, USA). Intralesional infectious agents were immunopositive for Prototheca zopfii antigen (Fig. 4). Molecular analysis confirmed an infection with Prototheca zopfii and further characterized the causative agent as Prototheca zopfii genotype 2. The histopathological findings together with the results of the IHC and molecular analysis were consistent with pyogranulomatous inflammation of the nasal skin and cutaneous mucosa of the right nostril caused by Prototheca zopfii genotype 2. Immediately after the microscopical diagnosis, treatment was initiated. The cat received ketoconazole (10 mg/kg) together with food twice a day for 20 days followed by the local application of terbinafine hydrochloride once a day for a further 6 weeks. The mucocutaneous lesions showed partial regression. Over the following 6 months, the cat progressively lost weight and finally showed seizure
289
activity. The owners elected for humane destruction, but a post-mortem examination was not permitted. Thus, it could not be determined if the Prototheca zopfii infection was restricted to the nasal area or had spread to other organs. To the authors’ knowledge, feline Prototheca zopfii genotype-2 induced disease has not been reported previously. In all five feline cases with speciation, Prototheca wickerhamii was identified (Kaplan et al., 1976; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). For characterization of the causative algae species, an immunofluorescent antibody (Kaplan et al., 1976) or biochemical methods (Kaplan et al., 1976; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010) were used. In the present case, however, a detailed molecular analysis was applied resulting in the identification of Prototheca zopfii genotype 2. The molecular characterization of Prototheca isolates will likely be beneficial for the identification of strain- or even genotype-specific treatment options in the future (Pal et al., 2014). Previously published cases of feline protothecosis were diagnosed in six adult cats aged 3e16 years; five of these were male and in one case the gender was unknown (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). Skin lesions of affected cats consisted of focal or multifocal (pyo) granulomatous dermatitis or cellulitis (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). The lesions measured 0.6 cme5 cm in diameter (Kaplan et al., 1976; Finnie and Coloe, 1981; Dillberger et al., 1988) and were located on the head, including the nasal area, ear and forehead, the distal limb and the
Fig. 4. Intralesional algae label positively for Prototheca zopfii antigen (arrowhead). IHC. Bar, 20 mm.
N. Huth et al.
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tail (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). Reported locations together with the present case indicate that the head may be a predilection site for feline protothecosis. Prototheca-induced dermatitis in human beings and dogs as well as bovine Prototheca-caused mastitis is likely initiated by a traumatic inoculation or wound contamination by the algae (Pal et al. 2014). This was also considered the most likely route of infection in the present case. Immunosuppression predisposes to protothecosis in human beings (Lass-Fl€orl and Mayr, 2007) and has also been discussed as a possible influencing factor in dogs (Stenner et al., 2007). Despite the detection of numerous algae in all published cases of feline protothecosis (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010), evidence of an impaired immune defence existed only in one cat that had a marked leucopenia, but tested negative for infection with FeLV and FIV (Endo et al., 2010). In this case and the previously published cases, no evidence for a disseminated disease was detected (Kaplan et al., 1976; Finnie and Coloe, 1981; Coloe and Allison, 1982; Dillberger et al., 1988; Endo et al., 2010). In one cat, however, there was involvement of the regional lymph node (Coloe and Allison, 1982). It has been postulated that certain Prototheca species and their subtypes may exist within a particular environmental niche (Blaschke-Hellmessen et al., 1985) and that they differ in regard to their virulence (Ahrholdt et al., 2012). The latter may explain the higher susceptibility of some domestic animals to infection with a particular Prototheca species or even genotypes. In conclusion, Protoheca zopfii genotype 2 has been identified as a pathogenic Prototheca species in cats and protothecosis should be included as a differential diagnosis for nodular (muco)cutaneous disease in this species.
References Ahrholdt J, Murugaiyan J, Straubinger RK, Jagielski T, Roesler U (2012) Epidemiological analysis of worldwide bovine, canine and human clinical Prototheca isolates by PCR genotyping and MALDI-TOF mass spectrometry proteomic phenotyping. Medical Mycology, 50, 234e243. Blaschke-Hellmessen R, Schuster H, Bergmann V (1985) Differenzierung von Varianten bei Prototheca zopfii Kr€ uger 1894. Archiv f€ur experimentelle Veterin€armedizin, 39, 387e397. Coloe PJ, Allison JF (1982) Protothecosis in a cat. Journal of the American Veterinary Medical Association, 180, 78e79.
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November 28th, 2014 ½ Received, Accepted, February 3rd, 2015