Cryptococcus albidus infection in a California sea lion (Zalophus californianus)

A case report of cryptococcosis in a captive Cape hyrax (Procavia capensis)

Cryptococcosis, a globally distributed mycotic disease caused by Cryptococcus neoformans or C. gattii, has been extensively studied in various domestic animals and humans. However, non-domestic species have often been overlooked in the literature, with limited attention given to their susceptibility and contribution to the epidemiology of the disease. In this study, a captive two-year-old Cape hyrax in a Japanese zoo exhibited neurological symptoms and torticollis, ultimately succumbing to the infection. Necropsy and pathological analyses, including histopathological techniques and PCR, revealed the presence of C. neoformans in the lungs, cerebrum, and internal auditory canal. While cryptococcosis has been reported in various wild animals globally, this case represents the first documented cryptococcosis in Cape hyrax.

RETROSPECTIVE REVIEW OF NEUROLOGIC DISEASE IN STRANDED ATLANTIC HARBOR SEALS (PHOCA VITULINA CONCOLOR) ALONG THE NEW ENGLAND COAST

Harbor seals (Phoca vitulina) are a common species admitted to marine mammal rehabilitation facilities. As important indicators of marine ecosystem health, monitoring trends of disease in harbor seal populations is critical. However, few studies have evaluated neurologic disease in this species. The general objective of this study was to retrospectively review and delineate neurologic disease in free-ranging Atlantic harbor seals (P. vitulina concolor) that stranded along the New England (United States) coast and entered a rehabilitation facility between 2006 and 2019. Any Atlantic harbor seal that stranded live along the New England coast during the study period and was diagnosed with neurologic disease on either antemortem or postmortem evaluation was included; medical records and pathologic reports were reviewed. From 211 records, 24 animals met the inclusion criteria. Prevalence of neurologic disease was 11% in the study population and six major categories of neurologic disease were identified including: inflammatory (54%), idiopathic (33%), trauma (4%), congenital (4%), and degenerative (4%). Of the seals diagnosed with neurologic disease, 13 (54%) seals died during rehabilitation, 10 (42%) seals were euthanized, and 1 (4%) seal survived to release. Unique cases seen included a seal with Dandy-Walker-like malformation and another seal with histopathologic findings compatible with neuroaxonal dystrophy, a degenerative process that has not been previously reported in marine mammals. This study contributes to the overall knowledge of the health of free-ranging Atlantic harbor seals and may aid clinicians in characterizing neurologic conditions that may be present in seals undergoing rehabilitation.

Cryptococcus in Wildlife and Free-Living Mammals

Cryptococcosis is typically a sporadic disease that affects a broad range of animal species globally. Disease is a consequence of infection with members of the Cryptococcus neoformans or Cryptococcus gattii species complexes. Although cryptococcosis in many domestic animals has been relatively well-characterized, free-living wildlife animal species are often neglected in the literature outside of occasional case reports. This review summarizes the clinical presentation, pathological findings and potential underlying causes of cryptococcosis in various other animals, including terrestrial wildlife species and marine mammals. The evaluation of the available literature supports the hypothesis that anatomy (particularly of the respiratory tract), behavior and environmental exposures of animals play vital roles in the outcome of host–pathogen–environment interactions resulting in different clinical scenarios. Key examples range from koalas, which exhibit primarily C. gattii species complex disease presumably due to their behavior and environmental exposure to eucalypts, to cetaceans, which show predominantly pulmonary lesions due to their unique respiratory anatomy. Understanding the factors at play in each clinical scenario is a powerful investigative tool, as wildlife species may act as disease sentinels.

Plasma concentrations of itraconazole following a single oral dose in juvenile California sea lions (Zalophus californianus)

The objective of this study was to establish a single-dose pharmacokinetic profile for orally administered itraconazole in California sea lions (Zalophus californianus). Twenty healthy rehabilitated juvenile California sea lions were included in this study. Itraconazole capsules were administered orally with food at a target dose of 5-10 mg/kg. Blood samples were collected from each animal at 0 hr and at two of the following timepoints: 0.5, 1, 2, 4, 6, 8, 12, 24, 48, and 72 hr. Quantitative analysis of itraconazole in plasma samples was performed by high-performance liquid chromatography. An average maximum concentration of 0.22 µg/ml ± 0.11 was detected 4 hr after administration. The average concentration fell to 0.12 µg/ml ± 0.11 by 6 hr and 0.02 µg/ml ± 0.02 at 12 hr. At no point did concentrations reach 0.5 µg/ml, the concentration commonly accepted for therapeutic efficacy. While this formulation was well tolerated by the sea lions, oral absorption was poor and highly variable among individuals. These data indicate that a single oral dose of itraconazole given as a capsule at 5-10 mg/kg, under the conditions used in this study, does not achieve therapeutic plasma concentrations in California sea lions.

Cryptococcus gattii Type VGIIa Infection in Harbor Seals ( Phoca vitulina ) in British Columbia, Canada

Cryptococcosis has been reported in marine mammals in the northeastern Pacific with increasing frequency in the last 15 yr. Although a variety of cetaceans have been diagnosed with cryptococcosis, Cryptococcus gattii has not been reported in pinnipeds. We document C. gattii VGIIa in a harbor seal ( Phoca vitulina ) pup and in an unrelated adult. Both animals were presented to Vancouver Aquarium's Marine Mammal Rescue Centre (VAMMRC) with generalized weakness, dehydration, respiratory compromise, minimally responsive mentation, and suboptimal body condition. Necropsy and histopathology findings were consistent in both animals and featured generalized lymphadenopathy, bronchopneumonia, and meningoencephalitis with intralesional yeast and fungemia. Cryptococcal serum antigen titers were ≥1,024 in both animals. Fungal culture of lung and lymph nodes confirmed C. gattii . Exposure was likely via inhalation prior to presentation to VAMMRC, and C. gattii infection was the proximate cause of death. This report expands the range of susceptible host species as C. gattii continues to emerge as a pathogen of concern in marine mammals in the northeastern Pacific.

Coccidioidomycosis and other systemic mycoses of marine mammals stranding along the central California, USA coast: 1998-2012

A wide range of systemic mycoses have been reported from captive and wild marine mammals from North America. Examples include regionally endemic pathogens such as Coccidioides and Blastomyces spp., and novel pathogens like Cryptococcus gattii, which appear may have been introduced to North America by humans. Stranding and necropsy data were analyzed from three marine mammal stranding and response facilities on the central California coast to assess the prevalence, host demographics, and lesion distribution of systemic mycoses affecting locally endemic marine mammals. Between 1 January 1998 and 30 June 2012, >7,000 stranded marine mammals were necropsied at the three facilities. Necropsy and histopathology records were reviewed to identify cases of locally invasive or systemic mycoses and determine the nature and distribution of fungal lesions. Forty-one animals (0.6%) exhibited cytological, culture- or histologically confirmed locally invasive or systemic mycoses: 36 had coccidioidomycosis, two had zygomycosis, two had cryptococcosis, and one was systemically infected with Scedosporium apiospermum (an Ascomycota). Infected animals included 18 California sea lions (Zalophus californianus), 20 southern sea otters (Enhydra lutris nereis), two Pacific harbor seals (Phoca vitulina richardsi), one Dall's porpoise (Phocoenoides dalli), and one northern elephant seal (Mirounga angustirostris). Coccidioidomycosis was reported from 15 sea lions, 20 sea otters, and one harbor seal, confirming that Coccidioides spp. is the most common pathogen causing systemic mycosis in marine mammals stranding along the central California coast. We also report the first confirmation of C. gattii infection in a wild marine mammal from California and the first report of coccidioidomycosis in a wild harbor seal. Awareness of these pathogenic fungi during clinical care and postmortem examination is an important part of marine mammal population health surveillance and human health protection. Temporal-spatial overlap may be observed for pathogenic mycoses infecting coastal marine mammals and adjacent human populations.

Cryptococcosis: epidemiology, fungal resistance, and new alternatives for treatment

Cryptococcosis is an important systemic mycosis and the third most prevalent disease in human immunodeficiency virus (HIV)-positive individuals. The incidence of cryptococcosis is high among the 25 million people with HIV/acquired immunodeficiency syndrome (AIDS), with recent estimates indicating that there are one million cases of cryptococcal meningitis globally per year in AIDS patients. In Cryptococcus neoformans, resistance to azoles may be associated with alterations in the target enzyme encoded by the gene ERG11, lanosterol 14α-demethylase. These alterations are obtained through mutations, or by overexpressing the gene encoding. In addition, C. gattii and C. neoformans present a heteroresistance phenotype, which may be related to increased virulence. Other species beyond C. neoformans and C. gattii, such as C. laurentii, have been diagnosed mainly in patients with immunosuppression. Infections of C. albidus have been isolated in cats and marine mammals. Recent evidence suggests that the majority of infections produced by this pathogen are associated with biofilm growth, which is also related with increased resistance to antifungal agents. Therefore, there is a great need to search for alternative antifungal agents for these fungi. The search for new molecules is currently occurring from nanoparticle drugs of plant peptide origin. This article presents a brief review of the literature regarding the epidemiology of cryptococcosis, as well as fungal resistance and new alternatives for treatment.