Geology Reports⌕ Search

Geology topics

E.R. Jacobson

Publications and source records attributed to E.R. Jacobson.

9 recordsLinked to original sources
USGS2002

Application of diagnostic tests for mycoplasmal infections of desert and gopher tortoises with management recommendations

Mycoplasmosis is a transmissible upper respiratory tract disease that has affected plans for management and conservation of wild desert and gopher tortoises in the United States. Although impact of mycoplasmosis on populations of desert and gopher tortoises is unknown, increased prevalence of seropositive animals as well as field observations of clinically ill tortoises have occurred in association with declining populations. In order to help in the identification of potentially infected animals, three tests have been developed to diagnose mycoplasmal infections of tortoises: 1) direct mycoplasmal culture; 2) detection of mycolplasmal chromosomal DNA by polymerase chain reaction (PCR); and 3) detection of anti-Mycoplasma antibodies in tortoise plasma by enzyme-linked immunosorbent assay (ELISA). Each test provides different, complementary information that collectively can be used to define tortoise mycoplasmal infection status. The types of samples required, the predictive value, interpretation, and cost vary among tests. These assays have been used for epidemiological surveys and in decision making for relocation, repatriation, or captive management of tortoises to minimize the risk of outbreaks of mycoplasmal respiratory disease and spread of the causative agent of this disease. Certain features of mycoplasmal infections of tortoises and other animals create a diagnostic dilemma. Multiple Mycoplasma species can cause respiratory disease with identical clinical presentations. Further, individual strains of a given species may vary with respect to their virulence potential, and some species may be commensals rather than pathogens. Current diagnostic tests may not differentiate among mycoplasmal species or strains or permit determination of pathogenicity of individual isolates. Thus, the information provided by testing is not a simple 'positive' vs. 'negative' issue. While these tests provide much needed information on the exposure of tortoise populations to Mycoplasma species, they do not provide a complete picture of the overall health status of individual tortoises or populations. Unfortunately, test results are often used to make life and death decisions concerning disposition of tortoises being displaced by land development without a complete understanding of the limitations of the diagnostic tests or any consideration of other infectious agents that might be present.

AZ, CA, FL, NV, UT↗
USGS2001

Mycoplasma agassizii sp., nov., isolated from the upper respiratory tract of the desert tortoise (Gopherus agassizii) and the gopher tortoise (Gopherus polyphemus).

Biochemical, serological and molecular genetic studies were performed on seven mycoplasma isolates that were recovered from the upper respiratory tract of clinically ill desert tortoises. The isolates were serologically related to each other but serologically distinct from previously described species. Unique mycoplasma species-specific 16S rRNA nucleotide sequences were found in the proposed type strain. The name Mycoplasma agassizii is proposed for these isolates. The type strain is PS6 T (=ATCC 700616 T ) which caused upper respiratory tract disease (URTD) in experimentally infected tortoises.

Nevada↗
USGS1998

Pathology of diseases in wild desert tortoises from California

Twenty-four ill or dead desert tortoises ( Gopherus agassizii ) were received between March 1992 and July 1995 for necropsies from the Mojave and Colorado deserts of California (USA). Diseases observed in these animals included cutaneous dyskeratosis ( n = 7); shell necrosis ( n = 2); respiratory diseases ( n = 7); urolithiasis ( n = 3); and trauma ( n = 5). In tortoises with cutaneous dyskeratosis the horn layer of shell was disrupted by multiple crevices and fissures and, in the most severe lesions, dermal bone showed osteoclastic resorption, remodeling, and osteopenia. In tortoises with shell necrosis, multiple foci of necrotic cell debris and heterophilic inflammation within the epidermal horn layer were subtended by necrotic dermal bone colonized by bacteria and fungi. Of the seven tortoises with respiratory disease, five were diagnosed with mycoplasmosis. The diagnosis of mycoplasmosis was based on the presence of chronic proliferative rhinitis and positive serologic tests and/or isolation of Mycoplasma sp. Chronic fungal pneumonia was diagnosed in one tortoise with respiratory disease. In the three tortoises with urolithiasis, two were discovered dead, and the live tortoise had renal and articular gout. Traumatic injuries consisted of one tortoise entombed within its burrow, one tortoise burned in a brush fire, two tortoises struck by moving vehicles, and one tortoise attacked by a predator. While the primary cause of illness could be attributed to one or two major disease processes, lesions were often found in multiple organ systems, and a variety of etiologies were responsible for morbidity and mortality.

Journal of Wildlife Diseases↗