Investigation of Investigation of Chronic Disease in a Chronic Disease in a Captive Mara ColonyCaptive Mara Colony
MexicoMexico
Index Case Index Case
July 21, 2001July 21, 2001 2 year old captive born male mara (2 year old captive born male mara (DolichotisDolichotis
patagonumpatagonum) died shortly after presenting with ) died shortly after presenting with weakness and anorexiaweakness and anorexia
Index Case-con’tIndex Case-con’t
Animal had disseminated fungal infection affecting Animal had disseminated fungal infection affecting mostly the liver, adrenal and lymph nodesmostly the liver, adrenal and lymph nodes
Cytology evaluation of the lymph node, adrenal and liver Cytology evaluation of the lymph node, adrenal and liver revealed numerous cytoplasmic yeast-like organismsrevealed numerous cytoplasmic yeast-like organisms 2-4 um in diameter2-4 um in diameter Clear halo surrounding themClear halo surrounding them In the cytoplasm of phagocytic cells and adrenocortical cellsIn the cytoplasm of phagocytic cells and adrenocortical cells
Gomori’s methenamine silver stain positive Gomori’s methenamine silver stain positive Histoplasma capsulatum var capsulatumHistoplasma capsulatum var capsulatum was isolated was isolated
from spleenfrom spleen
Case ConfirmationCase Confirmation
Gross necropsy findingsGross necropsy findings Histological findingsHistological findings Other testingOther testing
Special stainsSpecial stains Transmission electron microscopyTransmission electron microscopy Organism isolationOrganism isolation Exoantigen testExoantigen test ImmunohistochemistryImmunohistochemistry
Establishing Endemic LevelsEstablishing Endemic Levels
Intradermal testingIntradermal testing Common test in humans and equineCommon test in humans and equine Test location on abdomenTest location on abdomen 18/29 animals negative at 72 hours18/29 animals negative at 72 hours
No clinical, hematolgical, radiographic or No clinical, hematolgical, radiographic or immunologic evidence of histoplasmosis in immunologic evidence of histoplasmosis in these animalsthese animals
No prior cases of histoplasmosis in this No prior cases of histoplasmosis in this collectioncollection
Is There An outbreak?Is There An outbreak?
There is no evidence of histoplasmosis previous There is no evidence of histoplasmosis previous to these cases in the entire collectionto these cases in the entire collection
Is there the probability that more animals in the Is there the probability that more animals in the mara colony could have been exposed ot the mara colony could have been exposed ot the disease?disease? Maras use dens dug in the ground, each den is used Maras use dens dug in the ground, each den is used
several times by different femalesseveral times by different females The intradermal testing, that is the only practical The intradermal testing, that is the only practical
way to detect positive animals, was negative.way to detect positive animals, was negative.
Descriptive EpidemiologyDescriptive Epidemiology
Herd historyHerd history Environmental factorsEnvironmental factors
Herd HistoryHerd History
Mara colony at park for >20 yearsMara colony at park for >20 years 1997: 5 animals from Argentina added to group1997: 5 animals from Argentina added to group
1 male, 4 females1 male, 4 females Reproduction good since introduction (66 births)Reproduction good since introduction (66 births)
During time of the index caseDuring time of the index case Herd composed of 29 animalsHerd composed of 29 animals
Environmental FactorsEnvironmental Factors DietDiet
Water Water ad libitumad libitum Oranges, carrots, chopped alfalfa and rabbit pelletsOranges, carrots, chopped alfalfa and rabbit pellets
EnclosureEnclosure 120m120m22
Fenced with 1.20m high wire mesh and bamboo on one sideFenced with 1.20m high wire mesh and bamboo on one side Sandy substrateSandy substrate Often see squirrels (Often see squirrels (Spermophilus variegatusSpermophilus variegatus), Mice (), Mice (Mus musculusMus musculus) )
and various birds inside the enclosure.and various birds inside the enclosure. Often see opossum (Often see opossum (Didelphis virginianaDidelphis virginiana), ringtail cat (), ringtail cat (Bassariscus Bassariscus
astutusastutus) and stray cats () and stray cats (Felis domesticusFelis domesticus) inside the park.) inside the park. Several wild colonies of insectivorous bats (Several wild colonies of insectivorous bats (Tadarida brasiliensisTadarida brasiliensis))
Subsequent CasesSubsequent Cases
April 25, 2002April 25, 2002 Died after presenting with progressive weight Died after presenting with progressive weight
lossloss Severe granulomatous typhlocolitis and Severe granulomatous typhlocolitis and
moderate granulomatous gastrohepatic moderate granulomatous gastrohepatic lymphadenitis lymphadenitis
Similar organisms in the cytoplasm of Similar organisms in the cytoplasm of macrophagesmacrophages
Case #2Case #2 Gross necropsy findingsGross necropsy findings
Thickening of the large intestinal mucosaThickening of the large intestinal mucosa Watery to mucoid small intestinal contentsWatery to mucoid small intestinal contents
HistopathologyHistopathology Severe, chronic grnaulomatous and fibrosing Severe, chronic grnaulomatous and fibrosing
hepatitis and adrenalitis with foci of hepatitis and adrenalitis with foci of necrosuppurative inflammationnecrosuppurative inflammation
Granulomatous typhlocolitisGranulomatous typhlocolitis Adrenocortical cells had abundant similar organisms Adrenocortical cells had abundant similar organisms
in their cytoplasm with no associated lesionin their cytoplasm with no associated lesion Histoplasma capsulatum var. capsulatumHistoplasma capsulatum var. capsulatum was was
isolated from the liver and adrenal gland.isolated from the liver and adrenal gland.
Is This An Outbreak?Is This An Outbreak?
Retrospective review of 54 animals Retrospective review of 54 animals revealed no other lesions compatible with revealed no other lesions compatible with HistoplasmosisHistoplasmosis
Previously non-tested animals were tested Previously non-tested animals were tested with high-dose antigen testingwith high-dose antigen testing All animals negativeAll animals negative
Investigate immune status of animals and Investigate immune status of animals and contamination status of environmentcontamination status of environment
Immune Status and Immune Status and EnvironmentEnvironment
No previous evidence of histoplasmosis in this No previous evidence of histoplasmosis in this mara colonymara colony
High probability that more animals in the colony High probability that more animals in the colony could have been exposed to diseasecould have been exposed to disease
Intradermal testing is the only practical way to Intradermal testing is the only practical way to test these animalstest these animals questionable accuracyquestionable accuracy
Immunological status of the colony would Immunological status of the colony would contribute to presence of disseminated contribute to presence of disseminated histoplasmosis in more animalshistoplasmosis in more animals
HypothesesHypotheses
Unusual susceptibility of this species to Unusual susceptibility of this species to the diseasethe disease
Low immunological status of the groupLow immunological status of the group Predisposing them to diseasePredisposing them to disease
High environmental contaminationHigh environmental contamination
Investigate HypothesisInvestigate Hypothesis
Review literature for similar casesReview literature for similar cases Environmental InvestigationEnvironmental Investigation
Literature ReviewLiterature Review
No reports of disseminated histoplasmosis No reports of disseminated histoplasmosis in maras or any rodent speciesin maras or any rodent species
Report of a localized mucocutaneous Report of a localized mucocutaneous histoplasmosis in a rabbithistoplasmosis in a rabbit
Reports of histoplasmosis affecting the Reports of histoplasmosis affecting the skin and lymph nodes of Badgers in skin and lymph nodes of Badgers in EuropeEurope
Environmental InvestigationEnvironmental Investigation
Environmental sampling of mara areasEnvironmental sampling of mara areas No growthNo growth Mice inoculated with extracts of environmental Mice inoculated with extracts of environmental
samples DID seroconvertsamples DID seroconvert Demonstrates presence of organism in the Demonstrates presence of organism in the
enclosureenclosure
2 bat colonies in the park were sampled2 bat colonies in the park were sampled No culture growthNo culture growth NO seroconversion in miceNO seroconversion in mice
Environmental InvestigationEnvironmental Investigation
Climatic conditions of park does not promote the Climatic conditions of park does not promote the proliferation of the fungusproliferation of the fungus Sandy substrate, low humidity, lack of bird or bat Sandy substrate, low humidity, lack of bird or bat
droppingsdroppings But indirect evidence of fungal presence was foundBut indirect evidence of fungal presence was found
Bats play an important role in fungal Bats play an important role in fungal disseminationdissemination Abundance of insectivorous bats in parkAbundance of insectivorous bats in park
Other carnivorous wild animals in the park could Other carnivorous wild animals in the park could disseminate the fungusdisseminate the fungus Serology is pendingSerology is pending
Treatment and InterventionTreatment and Intervention
DisinfectDisinfect Foot baths with phenolic base productsFoot baths with phenolic base products Dedicated tools to affected areasDedicated tools to affected areas 80cm of dirt removed from enclosure and replaced80cm of dirt removed from enclosure and replaced Disinfection of holding areaDisinfection of holding area
Communicate to staffCommunicate to staff Provided with masksProvided with masks Review of personal hygiene Review of personal hygiene
QuarantineQuarantine All maras moved to quarantineAll maras moved to quarantine
Long TermLong Term
Control of immune status of the colonyControl of immune status of the colony Review sex ratio and demographicsReview sex ratio and demographics Review geneticsReview genetics
Monitor wild bat colonies within the parkMonitor wild bat colonies within the park
ReferencesReferences Chavez-Tapia D.B., R. Vargas-Yañes, G. Rodríguez-Arellanes, G. R. Peña-Sandoval, J. J. Chavez-Tapia D.B., R. Vargas-Yañes, G. Rodríguez-Arellanes, G. R. Peña-Sandoval, J. J.
Flores-Estrada, M Reyes-Mo0ntes, M. L. Taylor. 1998. El murciélago como reservorio y Flores-Estrada, M Reyes-Mo0ntes, M. L. Taylor. 1998. El murciélago como reservorio y responsable de la dispersión de responsable de la dispersión de Histoplasma capsulatumHistoplasma capsulatum en la naturaleza. Rev. Inst. Nal. Enf. en la naturaleza. Rev. Inst. Nal. Enf. Resp. Mex. 11(3):187-191Resp. Mex. 11(3):187-191
Kapustin N. Kanitz C. and Muech T. 1999. Identification of a retrovirus in Bennett`s (Kapustin N. Kanitz C. and Muech T. 1999. Identification of a retrovirus in Bennett`s (Macropus Macropus rufrogriseus fruticarufrogriseus frutica) and Dama () and Dama (Tammar) (Tammar) (Macrophus eugenniMacrophus eugenni) Wallabies. Proc. Am. As. Zoo ) Wallabies. Proc. Am. As. Zoo Vet. Pp; 262Vet. Pp; 262
Morita T., M. Kishimoto, A. Shimada, Y. Matsumoto and J. Shindo. 2001. Disseminated Morita T., M. Kishimoto, A. Shimada, Y. Matsumoto and J. Shindo. 2001. Disseminated histoplasmosis in a Sea Otter (histoplasmosis in a Sea Otter (Enhydra lutrisEnhydra lutris). J. Comp. Path . 125: 219-223.). J. Comp. Path . 125: 219-223.
Rezabek G. B., J. M. Donahue, R. C. Giles, M. B. Petrites-Murphy, K. B. Poonacha, J. R. Rezabek G. B., J. M. Donahue, R. C. Giles, M. B. Petrites-Murphy, K. B. Poonacha, J. R. Rooney, B, J, Smith, T. W. Swerczek and R. R. Tramontin. 1993. Histoplasmosis in Horses., Rooney, B, J, Smith, T. W. Swerczek and R. R. Tramontin. 1993. Histoplasmosis in Horses., J. Comp Path . 109:47-55.J. Comp Path . 109:47-55.
Rosas-Rosas A., C. J. Salles, G. Rodríguez-Arellanes, M. L. Taylos, M. M. Garner. 2004. Rosas-Rosas A., C. J. Salles, G. Rodríguez-Arellanes, M. L. Taylos, M. M. Garner. 2004. Disseminated Disseminated Histoplasma capsulatum var. capsulatumHistoplasma capsulatum var. capsulatum infection infection in a captive mara in a captive mara ( ( Dolichotis patagonumDolichotis patagonum) In Press……) In Press……
Taylor M. L., C. B. Chavez-Tapia, R. Vargas-Yañez, G. Rodríguez-Arellanes, G.R Peña-Taylor M. L., C. B. Chavez-Tapia, R. Vargas-Yañez, G. Rodríguez-Arellanes, G.R Peña-Sandoval, C Toriello, A. Perez and M. RSandoval, C Toriello, A. Perez and M. R. Reyez-Montes. . Reyez-Montes. 1999. Environmental conditions 1999. Environmental conditions Favouring Bat infection with histoplasma capsulatum in Mexican shelters. Am J. Trop. Med. Favouring Bat infection with histoplasma capsulatum in Mexican shelters. Am J. Trop. Med. Hyg. 61(6):914-919.Hyg. 61(6):914-919.
Taylos M.L, Reyes-Montes M. Chavez-Tapia C. B. Curiel-Quesada E. Duarte-Escalante E. Taylos M.L, Reyes-Montes M. Chavez-Tapia C. B. Curiel-Quesada E. Duarte-Escalante E. Rodríguez-Arellanes G. Peña-Sandoval G. R., and Valenzuela-Tovar F. Rodríguez-Arellanes G. Peña-Sandoval G. R., and Valenzuela-Tovar F. 2000. Ecology and 2000. Ecology and molecular epidemiology findings of Histoplasma capsulatum, in Mexico. Res. Adv. In molecular epidemiology findings of Histoplasma capsulatum, in Mexico. Res. Adv. In Microbiology. 1:29-35.Microbiology. 1:29-35.