Seroepidemiology of upper respiratory tract disease in the desert tortoise in the western Mojave desert of California

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

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Several factors have combined with an upper respiratory tract disease (URTD) to produce declines on some population numbers of desert tortoises (Gopherus agassizii) in the western USA. This study was designed to determine the seroepidemiology of URTD in a population of wild adult tortoises at the Desert Tortoise Research Natural Area (DTNA) study site in Kern County (California, USA). Prior to initiation of the study, there was a dramatic decline in the number of individuals in this population. At each individual time point, samples were obtained from 12 to 20 tortoises with radiotransmitters during winter, spring, summer, and fall from 1992 through 1995. During the course of the study, 35 animals were sampled at one or more times Only 10 animals were available for consistent monitoring throughout the 4 yr period. Specific antibody (Ab) levels to Mycoplasma agassizii were determined for individual tortoises by an enzyme-linked immunosorbent assay (ELISA) test. Specific Ab levels were not influenced by the gender of the tortoise. Levels of Ab and distribution of ELISA+, ELISA- and suspect animals were not consistently affected by season within a single year or for a season among the study years. Significantly more tortoises presented with clinical signs in 1992 and 1995. The profile of ELISA+ animals with clinical signs shifted from 5% (1992) to 42% (1995). In 1992, 52% of tortoises lacked clinical signs and were ELISA-. In 1995, this category accounted for only 19% of tortoises. Based on the results of this study, we conclude that URTD was present in this population as evidenced by the presence of ELISA+ individual animals, and that the infectious agent is still present as evidenced by seroconversion of previously ELISA-animals during the course of the study. There is evidence to suggest that animals may remain ELISA+ without showing overt disease, a clinical pattern consistent with the chronic nature of most mycoplasmal infections. Further, there are trends suggesting that the clinical expression of disease may be cyclical. Continued monitoring of this population could provide valuable information concerning the spread of URTD in wild tortoise populations.

Original languageEnglish (US)
Pages (from-to)716-727
Number of pages12
JournalJournal of Wildlife Diseases
Volume35
Issue number4
StatePublished - Oct 1999

Fingerprint

Gopherus agassizii
Mojave Desert
Respiratory Tract Diseases
Turtles
tortoises
serological surveys
respiratory tract diseases
desert
enzyme-linked immunosorbent assay
Enzyme-Linked Immunosorbent Assay
assay
enzyme
animals
animal
Population
antibody
antibodies
Mycoplasma agassizii
Antibodies
mycoplasmosis

Keywords

  • Epidemiology
  • Gopherus agassizii
  • Mycoplasma agassizii
  • Serology
  • Upper respiratory tract disease

ASJC Scopus subject areas

  • veterinary(all)

Cite this

Seroepidemiology of upper respiratory tract disease in the desert tortoise in the western Mojave desert of California. / Brown, Mary B.; Berry, Kristin H.; Schumacher, Isabella M.; Nagy, Kenneth A.; Christopher, Mary M; Klein, Paul A.

In: Journal of Wildlife Diseases, Vol. 35, No. 4, 10.1999, p. 716-727.

Research output: Contribution to journalArticle

Brown, Mary B. ; Berry, Kristin H. ; Schumacher, Isabella M. ; Nagy, Kenneth A. ; Christopher, Mary M ; Klein, Paul A. / Seroepidemiology of upper respiratory tract disease in the desert tortoise in the western Mojave desert of California. In: Journal of Wildlife Diseases. 1999 ; Vol. 35, No. 4. pp. 716-727.
@article{7ea3ff92d1d2493faca31dadb903cdb4,
title = "Seroepidemiology of upper respiratory tract disease in the desert tortoise in the western Mojave desert of California",
abstract = "Several factors have combined with an upper respiratory tract disease (URTD) to produce declines on some population numbers of desert tortoises (Gopherus agassizii) in the western USA. This study was designed to determine the seroepidemiology of URTD in a population of wild adult tortoises at the Desert Tortoise Research Natural Area (DTNA) study site in Kern County (California, USA). Prior to initiation of the study, there was a dramatic decline in the number of individuals in this population. At each individual time point, samples were obtained from 12 to 20 tortoises with radiotransmitters during winter, spring, summer, and fall from 1992 through 1995. During the course of the study, 35 animals were sampled at one or more times Only 10 animals were available for consistent monitoring throughout the 4 yr period. Specific antibody (Ab) levels to Mycoplasma agassizii were determined for individual tortoises by an enzyme-linked immunosorbent assay (ELISA) test. Specific Ab levels were not influenced by the gender of the tortoise. Levels of Ab and distribution of ELISA+, ELISA- and suspect animals were not consistently affected by season within a single year or for a season among the study years. Significantly more tortoises presented with clinical signs in 1992 and 1995. The profile of ELISA+ animals with clinical signs shifted from 5{\%} (1992) to 42{\%} (1995). In 1992, 52{\%} of tortoises lacked clinical signs and were ELISA-. In 1995, this category accounted for only 19{\%} of tortoises. Based on the results of this study, we conclude that URTD was present in this population as evidenced by the presence of ELISA+ individual animals, and that the infectious agent is still present as evidenced by seroconversion of previously ELISA-animals during the course of the study. There is evidence to suggest that animals may remain ELISA+ without showing overt disease, a clinical pattern consistent with the chronic nature of most mycoplasmal infections. Further, there are trends suggesting that the clinical expression of disease may be cyclical. Continued monitoring of this population could provide valuable information concerning the spread of URTD in wild tortoise populations.",
keywords = "Epidemiology, Gopherus agassizii, Mycoplasma agassizii, Serology, Upper respiratory tract disease",
author = "Brown, {Mary B.} and Berry, {Kristin H.} and Schumacher, {Isabella M.} and Nagy, {Kenneth A.} and Christopher, {Mary M} and Klein, {Paul A.}",
year = "1999",
month = "10",
language = "English (US)",
volume = "35",
pages = "716--727",
journal = "Journal of Wildlife Diseases",
issn = "0090-3558",
publisher = "Wildlife Disease Association, Inc.",
number = "4",

}

TY - JOUR

T1 - Seroepidemiology of upper respiratory tract disease in the desert tortoise in the western Mojave desert of California

AU - Brown, Mary B.

AU - Berry, Kristin H.

AU - Schumacher, Isabella M.

AU - Nagy, Kenneth A.

AU - Christopher, Mary M

AU - Klein, Paul A.

PY - 1999/10

Y1 - 1999/10

N2 - Several factors have combined with an upper respiratory tract disease (URTD) to produce declines on some population numbers of desert tortoises (Gopherus agassizii) in the western USA. This study was designed to determine the seroepidemiology of URTD in a population of wild adult tortoises at the Desert Tortoise Research Natural Area (DTNA) study site in Kern County (California, USA). Prior to initiation of the study, there was a dramatic decline in the number of individuals in this population. At each individual time point, samples were obtained from 12 to 20 tortoises with radiotransmitters during winter, spring, summer, and fall from 1992 through 1995. During the course of the study, 35 animals were sampled at one or more times Only 10 animals were available for consistent monitoring throughout the 4 yr period. Specific antibody (Ab) levels to Mycoplasma agassizii were determined for individual tortoises by an enzyme-linked immunosorbent assay (ELISA) test. Specific Ab levels were not influenced by the gender of the tortoise. Levels of Ab and distribution of ELISA+, ELISA- and suspect animals were not consistently affected by season within a single year or for a season among the study years. Significantly more tortoises presented with clinical signs in 1992 and 1995. The profile of ELISA+ animals with clinical signs shifted from 5% (1992) to 42% (1995). In 1992, 52% of tortoises lacked clinical signs and were ELISA-. In 1995, this category accounted for only 19% of tortoises. Based on the results of this study, we conclude that URTD was present in this population as evidenced by the presence of ELISA+ individual animals, and that the infectious agent is still present as evidenced by seroconversion of previously ELISA-animals during the course of the study. There is evidence to suggest that animals may remain ELISA+ without showing overt disease, a clinical pattern consistent with the chronic nature of most mycoplasmal infections. Further, there are trends suggesting that the clinical expression of disease may be cyclical. Continued monitoring of this population could provide valuable information concerning the spread of URTD in wild tortoise populations.

AB - Several factors have combined with an upper respiratory tract disease (URTD) to produce declines on some population numbers of desert tortoises (Gopherus agassizii) in the western USA. This study was designed to determine the seroepidemiology of URTD in a population of wild adult tortoises at the Desert Tortoise Research Natural Area (DTNA) study site in Kern County (California, USA). Prior to initiation of the study, there was a dramatic decline in the number of individuals in this population. At each individual time point, samples were obtained from 12 to 20 tortoises with radiotransmitters during winter, spring, summer, and fall from 1992 through 1995. During the course of the study, 35 animals were sampled at one or more times Only 10 animals were available for consistent monitoring throughout the 4 yr period. Specific antibody (Ab) levels to Mycoplasma agassizii were determined for individual tortoises by an enzyme-linked immunosorbent assay (ELISA) test. Specific Ab levels were not influenced by the gender of the tortoise. Levels of Ab and distribution of ELISA+, ELISA- and suspect animals were not consistently affected by season within a single year or for a season among the study years. Significantly more tortoises presented with clinical signs in 1992 and 1995. The profile of ELISA+ animals with clinical signs shifted from 5% (1992) to 42% (1995). In 1992, 52% of tortoises lacked clinical signs and were ELISA-. In 1995, this category accounted for only 19% of tortoises. Based on the results of this study, we conclude that URTD was present in this population as evidenced by the presence of ELISA+ individual animals, and that the infectious agent is still present as evidenced by seroconversion of previously ELISA-animals during the course of the study. There is evidence to suggest that animals may remain ELISA+ without showing overt disease, a clinical pattern consistent with the chronic nature of most mycoplasmal infections. Further, there are trends suggesting that the clinical expression of disease may be cyclical. Continued monitoring of this population could provide valuable information concerning the spread of URTD in wild tortoise populations.

KW - Epidemiology

KW - Gopherus agassizii

KW - Mycoplasma agassizii

KW - Serology

KW - Upper respiratory tract disease

UR - http://www.scopus.com/inward/record.url?scp=0033203557&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033203557&partnerID=8YFLogxK

M3 - Article

VL - 35

SP - 716

EP - 727

JO - Journal of Wildlife Diseases

JF - Journal of Wildlife Diseases

SN - 0090-3558

IS - 4

ER -