Papers by Tyla Holsomback
The American journal of tropical medicine and hygiene, 2005
What is currently known about the ecology of North American hantaviruses has come largely from st... more What is currently known about the ecology of North American hantaviruses has come largely from studies on Sin Nombre virus (SNV). We conducted a longitudinal study of Bayou virus (BAYV), the second-leading agent of hantavirus pulmonary syndrome in the United States. Antibodies to hantavirus were detected from Oryzomys palustris (most commonly infected species), Sigmodon hispidus, Peromyscus leucopus, Reithrodontomys fulvescens, and Baiomys taylori. However, only O. palustris had viral RNA in tissues and excreta, suggesting that antibodies detected in other species may have resulted from spill-over infection. Seroprevalence rates averaged around 16% for O. palustris and varied seasonally. The heaviest males exhibited the highest levels of seroprevalence. Seroprevalence was higher in coastal prairie (20.0%) than old-fields (10.5%) and was associated with host abundance. These patterns are similar to those of SNV and can be used in identification of potentially at-risk areas.
The Southwestern Naturalist, 2007
A B S T R A C T -A~~~~~~~ the swimming behavior of Olyzomys palustrir has been described, little ... more A B S T R A C T -A~~~~~~~ the swimming behavior of Olyzomys palustrir has been described, little is known about how long this species will remain in an area that is inundated by several centimeters of water. This study documents the response of an 0. palustris population to habitat inundation in a coastal prairie locality of southeastern Texas. During a mark-recapture study conducted during 2002 and 2003, we livetrapped 0. pnlustris on a grid in an area that experienced prolonged ( 2 5 mo) inundation during 2 of our 6 quarterly trapping periods. We describe a trapping technique, using foam rafts to support rodent live-traps, that is suitable for use in inundated areas. Despite long-term inundation, little available refuge, and an apparent complete turnover of the population, we estimated population densities of ca. 29 individuals per hectare during inundation, only a moderate decrease from the higher levels encountered befbre and after inundation.
Correlaciones ecológicas del estatus serológico para el virus Bayou en Oryzomys palustris (Rodentia: Sigmodontinae)
Mastozoología neotropical, Jun 1, 2009
Home range size and habitat use of seropositive Oryzomys palustris, primary host for the Bayou st... more Home range size and habitat use of seropositive Oryzomys palustris, primary host for the Bayou strain of hantavirus, were compared to that of seronegative individuals from March 2002-August 2003 in a longitudinal field population study. There were significant macrohabitat associations with serological status, but selection for most microhabitat variables did not differ between seropositive and seronegative animals. Seropositive adult males moved farther (had larger home ranges) than did seronegatives and were larger in ...
Mastozoología neotropical, Jun 1, 2009
ABSTRACT: Home range size and habitat use of seropositive Oryzomys palustris, primary host for th... more ABSTRACT: Home range size and habitat use of seropositive Oryzomys palustris, primary host for the Bayou strain of hantavirus, were compared to that of seronegative individuals from March 2002-August 2003 in a longitudinal field population study. There were significant macrohabitat associations with serological status, but selection for most microhabitat variables did not differ between seropositive and seronegative animals. Seropositive adult males moved farther (had larger home ranges) than did seronegatives and were larger in ...
Journal of Vector Ecology, 2009
In the United States, Bayou virus (BAYV) ranks second only to Sin Nombre virus (SNV) in terms of ... more In the United States, Bayou virus (BAYV) ranks second only to Sin Nombre virus (SNV) in terms of hantavirus pulmonary syndrome (HPS) incidents, having been confirmed in cases from Texas and Louisiana since its discovery in 1994. This study on BAYV infection among sympatric, non-oryzomyine rodents ("spillover") in Freeport, TX, is the first to link patterns of hantavirus interspecific spillover with the spatiotemporal ecology of the primary host (marsh rice rat, Oryzomys palustris). Mark-recapture and/or harvest methods were employed from March 2002 through May 2004 in two macrohabitat types. Rodent blood samples were screened for the presence of IgG antibody to BAYV antigen by IFA after which Ab-positive blood, saliva, and urine were analyzed for the presence of viral RNA by nested RT-PCR. From 727 non-oryzomyine captures, five seropositive (but not viral RNA positive) individuals were detected: one each of Baiomys taylori, Peromyscus leucopus, and Reithrodontomys fulvescens; and two Sigmodon hispidus. Spillover hosts were not associated with macrohabitat where O. palustris abundance, density, or seroprevalence was highest. Rather, spillover occurred in the macrohabitat indicative of greater overall disturbance (as indicated by grazing and exotic plant diversity) and overall biodiversity. Spillover occurred during periods of high seroprevalence detected elsewhere within the study region. Spillover locations differed significantly from all other capture locations in terms of percent water, shrub, and grass cover. Although greater habitat and mammal diversity of old-fields may serve to reduce seroprevalence levels by tempering intraspecific contacts between rice rats, greater diversity also may create an ecologically opportunistic setting for BAYV spillover. Impacts of varying levels of disturbance and biodiversity on transmission dynamics represent a vastly uncharacterized component of the evolutionary ecology of hantaviruses. Journal of Vector Ecology 34 (1): 9-21. 2009. Keyword Index: Bayou virus (BAYV) spillover, Oryzomys palustris, virus-host specificity, host switching, marsh rice rat.
Uploads
Papers by Tyla Holsomback