Seroepidemiology of Upper Respiratory Tract Disease in the Desert Tortoise in the Western Mojave Desert of California

Brown, Mary Bomberger; Berry, Kristin H.; Schumacher, Isabella M.; Nagy, Kenneth A.; Christopher, Mary M.; Klein, Paul

doi:10.7589/0090-3558-35.4.716

Cited by 48 publications

(43 citation statements)

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“…If swollen, the dimensions of each gland should be measured to estimate volume (see Alberts et al, 1994 for measurements and formula). The surface of the eye, appearance of palpebrae (eyelids), and periocular region should be examined closely for abnormal color; presence of dampness, mucus or drainage; and edema-all of which may be signs of URTD (Jacobson et al, 1991;Brown et al, 1994), rhinitis (Jackson, 1991) or other illnesses. The palpebrae are normally dry, unscaled, wrinkled, and delicate in appearance (Fig.…”

Section: The Health Profile Formmentioning

confidence: 99%

“…Permanent photographic records have proved invaluable for retrospective analyses of progression and regression of signs of diseases in individual animals and populations, including cutaneous dyskeratosis and other shell lesions Homer et al, 1998); URTD (Brown et al, 1999); traumatic injuries; and epidemiological research. Photographs also have proven to be a valid and reliable approach for grading trachoma in humans (West and Taylor, 1990).…”

Section: Permanent Photographic Recordsmentioning

confidence: 99%

“…Two recently described diseases, upper respiratory tract disease (URTD) and cutaneous dyskeratosis, were associated with population declines in some areas Jacobson et al, 1995;Berry, 1997b). Upper respiratory tract disease is caused by Mycoplasma agassizii (Jacobson et al, 1991;Brown et al, 1994) and an as yet unnamed new mycoplasma organism (Brown et al, 1995). An enzyme-linked immunosorbent assay (ELISA) test was developed to measure antibodies to Mycoplasma agassizii in tortoises .…”

Section: Introductionmentioning

confidence: 99%

“…An enzyme-linked immunosorbent assay (ELISA) test was developed to measure antibodies to Mycoplasma agassizii in tortoises . URTD and exposure to mycoplasma, as evidenced by positive ELISA tests and presence of mycoplasma in nasal secretions by cultures or polymerase chain reaction tests, have been documented in tortoises at multiple sites in the Mojave Desert (Jacobson et al, 1995;Dickinson et al, 1995;Homer et al, 1998;Brown et al, 1999). Upper respiratory tract disease is a transmissible disease, often subclinical and generally chronic Jacobson et al, 1995;Homer et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…Techniques for recording journal notes and information about live tortoises were developed, tested, and revised between 1971 and 1998 at 27 study plots in the California deserts (e.g., Berry and Medica 1995;Berry 1997b) with Ͼ20,000 captures of wild tortoises. Most techniques for assessing health and disease were developed and tested between 1988 and 1998 at 36 sites in California with Ͼ5,000 captures of tortoises (e.g., Berry, 1997b;Henen et al, 1998;Homer et al, 1998;Brown et al 1999;Christopher et al, 1999). These standardized field methods represent a productive collaboration between wildlife biologists, veterinarians and pathologists, and are applicable to other chelonians and reptiles.…”

Section: Introductionmentioning

confidence: 99%

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Guidelines for the Field Evaluation of Desert Tortoise Health and Disease

Berry

Christopher

2001

Journal of Wildlife Diseases

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Field evaluation of free-ranging wildlife requires the systematic documentation of a variety of environmental conditions and individual parameters of health and disease, particularly in the case of rare or endangered species. In addition, defined criteria are needed for the humane salvage of ill or dying animals. The purpose of this paper is to describe, in detail, the preparation, procedures, and protocols we developed and tested for the field evaluation of wild desert tortoises (Gopherus agassizii). These guidelines describe: preparations for the field, including developing familiarity with tortoise behavior and ecology, and preparation of standardized data sheets; journal notes to document background data on weather conditions, temperature, rainfall, locality, and historic and recent human activities; procedures to prevent the spread of disease and parasites; data sheets for live tortoises to record tortoise identification, location, sex, body measurements and activity; health profile forms for documenting and grading physical abnormalities of tortoise posture and movements, general condition (e.g., lethargy, cachexia), external parasites, and clinical abnormalities associated with shell and upper respiratory diseases; permanent photographic records for the retrospective analysis of progression and regression of upper respiratory and eye diseases, analysis of shell lesions and evaluation of growth and age; and indications and methods for salvaging ill or dying tortoises for necropsy evaluation. These guidelines, tested on 5,000 to 20,000 tortoises over a 10 to 27 yr period, were designed to maximize acquisition of data for demographic, ecological, health and disease research projects; to reduce handling and stress of individual animals; to avoid spread of infectious disease; to promote high quality and consistent data sets; and to reduce the duration and number of field trips. The field methods are adapted for desert tortoise life cycle, behavior, anatomy, physiology, and pertinent disease; however the model is applicable to other species of reptiles. Comprehensive databases of clinical signs of disease and health are crucial to research endeavors and essential to decisions on captive release, epidemiology of disease, translocation of wild tortoises, breeding programs, and euthanasia.

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Section: The Health Profile Formmentioning

confidence: 99%

Section: Permanent Photographic Recordsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Guidelines for the Field Evaluation of Desert Tortoise Health and Disease

Berry

Christopher

2001

Journal of Wildlife Diseases

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Distance to human populations influences epidemiology of respiratory disease in desert tortoises

et al. 2014

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We explored variables likely to affect health of Agassiz's desert tortoises (Gopherus agassizii) in a 1,183-km 2 study area in the central Mojave Desert of California between 2005 and 2008. We evaluated 1,004 tortoises for prevalence and spatial distribution of 2 pathogens, Mycoplasma agassizii and M. testudineum, that cause upper respiratory tract disease. We defined tortoises as test-positive if they were positive by culture and/ or DNA identification or positive or suspect for specific antibody for either of the two pathogens. We used covariates of habitat (vegetation, elevation, slope, and aspect), tortoise size and sex, distance from another test-positive tortoise, and anthropogenic variables (distances to roads, agricultural areas, playas, urban areas, and centroids of human-populated census blocks). We used both logistic regression models and regression trees to evaluate the 2 species of Mycoplasma separately. The prevalence of test-positive tortoises was low: 1.49% (15/1,004) for M. agassizii and 2.89% (29/1,004) for M. testudineum. The spatial distributions of testpositive tortoises for the 2 Mycoplasma species showed little overlap; only 2 tortoises were test-positive for both diseases. However, the spatial distributions did not differ statistically between the 2 species. We consistently found higher prevalence of test-positive tortoises with shorter distances to centroids of humanpopulated census blocks. The relationship between distance to human-populated census blocks and tortoises that are test-positive for M. agassizii and potentially M. testudineum may be related to release or escape of captive tortoises because the prevalence of M. agassizii in captive tortoises is high. Our findings have application to other species of chelonians where both domestic captive and wild populations exist. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

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The Catastrophic Decline of Tortoises at a Fenced Natural Area

Berry

Yee

Shields³

et al. 2020

Wildlife Monographs

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Agassiz's desert tortoise (Gopherus agassizii), a threatened species of the southwestern United States, has severely declined to the point where 76% of populations in critical habitat (Tortoise Conservation Areas) are below viability. The potential for rapid recovery of wild populations is low because females require 12-20 years to reach reproductive maturity and produce few eggs annually. We report on a 34-year mark-recapture study of tortoises initiated in 1979 at the Desert Tortoise Research Natural Area in the western Mojave Desert, California, USA, and provide substantive data on challenges faced by the species. In 1980, the United States Congress designated the Research Natural Area and protected the land from recreational vehicles, livestock grazing, and mining with a wildlife-permeable fence. The 7.77-km 2 study area, centered on interpretive facilities, included land both within the Natural Area and outside the fence. We expected greater benefits to accrue to the tortoises and habitat inside compared to outside. Our objectives were to conduct a demographic study, analyze and model changes in the tortoise population and habitat, and compare the effectiveness of fencing to protect populations and habitat inside the fence versus outside, where populations and habitat were unprotected. We conducted surveys in spring in each of 7 survey years from 1979, when the fence was under construction, through 2012. We compared populations inside to those outside the fence by survey year for changes in distribution, structure by size and relative age, sex ratios, death rates of adults, and causes of death for all sizes of tortoises. We used a Bayesian implementation of a Jolly Seber model for mark-recapture data. We modeled detection, density, growth and transition of tortoises to larger size-age classes, movements from inside the protective fence to outside and vice versa, and survival. After the second and subsequent survey years, we added surveys to monitor vegetation and habitat changes, conduct health assessments, and collect data on counts of predators and predator sign. At the beginning of the study, counts and densities for all sizes of tortoises were high, but densities were approximately 24% higher inside the fence than outside. By 2002, the low point in densities, densities had declined 90% inside the fence and 95% outside. Between 2002 and 2012, the population inside the fence showed signs of improving with a 54% increase in density. Outside the fence, densities remained low. At the end of the study, when we considered the initial differences in location, densities inside the fence were roughly 2.5 times higher than outside. The pattern of densities was similar for male and female adults. When evaluating survival by blocks of years, survivorship was higher in 1979-1989 than in 1989-2002 (the low point) and highest from 2002 to 2012. Recruitment and survival of adult females into the population was important for growing the population, but survival of all sizes, including juveniles, was also critical.Major ...

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Seroepidemiology of Upper Respiratory Tract Disease in the Desert Tortoise in the Western Mojave Desert of California

Cited by 48 publications

References 9 publications

Guidelines for the Field Evaluation of Desert Tortoise Health and Disease

Guidelines for the Field Evaluation of Desert Tortoise Health and Disease

Distance to human populations influences epidemiology of respiratory disease in desert tortoises

The Catastrophic Decline of Tortoises at a Fenced Natural Area

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