My name is Myrtha and I am a graduate student in the Biology Department at Western Illinois University. I am currently working with Dr. Richard Musser on the genetic expression of caterpillars that feed on Maize plants treated with the fungus Phialocephala fortinii. Taking medical mycology with Dr. Porras-Alfaro has exposed me to a variety of fungus and I have gained essential knowledge that I am able to apply to my current research. In this blog I will introduce you to an interesting fungi Lacazia loboi. 

Lobomycosis: Lacazia loboi

Taxonomy

Domain: Eukaryote

Kingdom: Fungi

Phylum: Ascomycota

Order: Onygenales

Genus: Lacazia

Species: loboi (only known species) 

General description

            Lacazia loboi is a fungal pathogen and the causative agent of an infection called lobomycosis. Lobomycosis commonly called lacaziosis, Jorge’s Disease, and Jorge Lôbo’s Disease is a chronic disease that affects humans and dolphins following traumatic injuries to the skin (2, 6, 7). The disease can manifest as cutaneous or subcutaneous lobomycosis characterized by smooth, verrucoses, or ulcerated nodules on the ear lobes and limbs in humans; on the head, flippers, flukes, dorsal fin, and peduncle in dolphins (2, 6, 8).  

Fig 1.Stained tissues infected with Lacazia loboi (Doctor fungus)

The onset of the disease varies from a few months to several years (1). Analysis of biopsied tissues taken from patients reveals chains of spherical yeast-like cells (5 to 12μm) connected with tubules, and thick-walled cell (1, 6).  The cells are engulfed and digested by histiocytes (5).  Most fungal stains can be used to successfully detect the presence of L. loboi. Because of its strong resistance to in vitro cultivation, biological and epidemiological features of L. loboi remain unknown  (1, 6, 10). However, results of phylogenetic analysis allow researchers to place this pathogenic fungus in the order Onygenales and as the sister taxon of the fungal pathogen Paracoccidioides brasiliensis (1, 6). 

 Lacazia loboi has been given various names over the years such as Glenosporella loboi, Glenosporosis amazonica, Lobomyces loboi and Loboa loboi (5, 9, 11). Humans and a few species of dolphins, Tusiops truncates and Sotalia guianensi, are the major hosts of this disease (4). Lobomycosis seems to affect older population of dolphins with immunosuppressed systems (2). Although the disease shows similar symptoms in humans and dolphins, microscopic shows some morphological differences in the size of the lesions and the destruction of the cell.  The fungal structures that affect human are significantly larger than those that affect dolphins (5). 

Fig. 2 Verrucoid lesions on a person infected with Lacazia loboi   http://www.mycology.adelaide.edu.au/Mycoses/Subcutaneous/Lobomycosis/

Fig 3. Dolphin showing signs of lobomycosis
(http://wwwnc.cdc.gov/eid/article/15/4/08-1358-f2.htm)on

Distribution

             Lacazia loboi is found in tropical regions such as Brazil, Bolivia, Colombia, Costa Rica, Guyana, Ecuador, French Guiana, Mexico, Peru, Panama, Surinam, and Venezuela (1, 6, 8). The endemic regions are humid, with large forests and rivers, and have over 200 cm of rain annually (9).  Several human cases have also been reported in Holland, Bangladesh, Canada, the United States in Florida and Georgia (1, 3).  And the few individuals infected reported traveling in the endemic areas several years preceding the onset of the disease (1). Numerous cases of L. loboi  in dolphins have been reported in several areas of Florida (Gulf coast, Vero Beach, the Atlantic coast and Marineland) and the Surinam River estuary, the Spanish-French coast, the south Brazilian coast, the Indian River Lagoon, and the Texas coast of the Gulf of Mexico (10). 

Habitat

Lacazia loboi’s natural reservoir is still unknown, though its occurrence in dolphins led researchers to believe that L. loboi lives in aquatic environments (8, 12). Based on the results of molecular testing it is known that L. loboi is indeed a dimorphic fungus that exists as a hyphae in nature (7).

Look Alikes

            Paracoccidioides brasiliensis and L. loboi share similar yeast-like cells. Due to the presence of melanin in the cell wall of L. loboi it was thought to be related to the black fungi Cladosporium sphaerospermum (6). 

Case study 1

            A 42-year-old male from Georgia came to a general surgeon with a raised 3.5 by 2 cm smooth nodule on his chest. The nodule appeared reddish purple surrounded by keloidal scar tissue. The biopsied tissues were stained and examined microscopically (1). The results showed:

-       inflamed infiltrate of foamy histiocytes with globose and subglobose lemon-shaped budding cells with diameter between 5 to 11 μm.

-       narrow tubular connections between daughter and mother cells.

-       multinucleated giant cells

-       scattered lymphocytes

The patient reported traveling to Venezuela, one of the lobomycosis-endemic countries a few years prior to the onset of the disease.

Treatment: The patient was treated by excising the lesion via an uncomplicated procedure. It was reported that the patient recovered fully (1).

Click on this link http://www.ncbi.nlm.nih.gov/pubmed/10699043 for more information on the case.

 

Case study 2

            A 42-year-old female from Canada presented to her doctor with a plaque-like lesion on her upper right arm. The lesion appeared red with a diameter of 1.5cm surrounded by keloidal scar tissue and emerged on the same spot where a lesion was removed a few years earlier. The patient not only travelled to lobomycosis endemic regions such as Mexico, Costa Rica but also lived in Guyana and Venezuela for 2 years. Biopsied tissues taken from the patient were stained and examined (3). The results showed:

-       multinucleated giant cells

-       thick-walled and spherical or lemon-shaped budding cells with a diameter of 10 μm

-       Cells were in chains and joined by narrow tubular connections

Treatment: The lesion was excised and the patient recovered completely (3).

Click on this link http://wwwnc.cdc.gov/eid/article/10/4/pdfs/03-0416.pdf for more details on the case. 

Case study 3
Two cases of lobomycosis in bottlenose dolphins (Tusiops truncates) in North Carolina. The first dolphin, a male Atlantic bottlenose, was found dead on the North Carolina coast. Multiple areas of the dolphin’s skin were covered with raised, ulcerated, and papillary nodules, and cutaneous lesions (10). 

Fig. 4 A. Serpigenous dermal nodules on a dolphin.
        B. Microscopic view of spherical fungi connected to each other

http://wwwnc.cdc.gov/eid/article/15/4/08-1358_article.htm

Microscopic stains of the lesions revealed:

-       cutaneous and subcutaneous nodule with   
     giant cells

-       lymphocytes

-       plasma cells

-       epithelioid macrophages

-       spherical fungi with diameters between 6 and 10 μm connected to each other by small tubules.

The second dolphin was a live male and was also found in North Carolina. Dermal nodules enclosing fungal yeast like structures (10).

Treatment: No treatment was listed for this case study.

Click on this link http://wwwnc.cdc.gov/eid/article/15/4/08-1358_article.htm for more details on the cases.

Glossary

Histiocytes: multinucleated giant cells

Keloidal scar: is a result of an overgrowth of tissue at the site of skin injury.

References

1. Burns, R.A., Roy, J. S., Woods, C., Padhye, A.A., Warnock, D.W. (2000). Report of the first human case of Lobomycosis in the United States. Journal of Clinical Microbiology. 38(3): 1283-1285.

2. Durden, W.N., St. Leger, J., Stolen, M., Mazza, T., Londono, C. (2009). Lacaziosis in bottlenose dolphins (Tursiops truncates) in the Indian river Lagoon, FL, USA. Journal of Wildlife Diseases. 45(3): 849-856.

3. Elsayed, S., Kuhn, S.M., Barber, D., Church, D.L., Adams, S., Kasper, R. (2004). Human case of Lobomycosis. Centers for Disease Control and Prevention. 10(4).

4. Hart, L. (2009). The prevalence and progression of lobomycosis in Sarasota Bay dolphins. Health and Physiology. Retrieved from http://wwwnc.cdc.gov/eid/article/15/4/08-1358_article.htm 3/4/2013.

5. Haubold, E.M., Cooper Jr., C.R., Wen, J.W., McGinnis, M.R., Cowan, D.F.(2000). Comparative morphology of Lacazia loboi (syn. Loboa loboi) in dolphins and humans. Journal of Medical Mycology. (38): 9-10.

6. Herr, R.A., Tarcha, E.J., Taborda, P.R., Taylor, J.W., Ajello, L., Mendoza, L. (2000). Phylogenetic analysis of Lacazia loboi  places this previously uncharacterized pathogen within the dimorphic Onygenales. Journal of Clinical Microbiology. 39(1): 309-314. 

7. Mendoza, L., Ajello, L., Taylor, J.W. (2001). The taxonomic status of Lacazia loboi and Rhinosporidium seeberi has been finally resolved with the use of molecular tools. Revista Iberoamericana de Micología. 18: 95-98.

8. Murdoch, M.E., Reif, J.S., Mazzoil, M., McCulloch, S.D., Fair, P.A., Bossart, G.D. (2008). Lobomycosis in Bottlenose Dolphins (Tursiops truncates) from the Indian River Lagoon,  Florida: Estimation of prevalence, temporal trends, and spatial distribution. International Association for Ecology and Health. 5: 289-297.

9. Reiss, E., Shadomy, H.J., Lyon, G.M. 2012. Fundamental Medical Mycology. New Jersey, NY: John Wiley & Sons, Inc.

10. Rotsein, D.S., Burdett, L.G., McLellan, W., Schwacke, L., Rowles, T, Terio, K.A., …Pabst, A. (2009). Lobomycosis in offshore bottlenose dolphins (Tursiops truncates), North Carolina. Emerging Infectious Diseases. 15(4):588-590.

11.  Taborda, P.R., Taborda, V.A., McGinnis, M.R. (1999). Lacazia loboi gen. nov., comb. nov.,  the etiologic agent of Lobomycosis. Journal of Clinical Microbiology. 37 (6): 2031-2033.

12.  Vilela, R., Mendoza, L., Rosa, P.S., Belone, A.F.F.B., Madeira, S., Opromolla, D.V.A., de Resende, M.A. (2005). Molecular model for studying the uncultivated fungal pathogen Lacazia loboi. Journal of Clinical Microbiology. 43(8): 3657-33661.