Caudal Polymorphism and Cephalic Morphology among First-Stage Larvae of \u3ci\u3eParelaphostrongylus odocoilei\u3c/i\u3e (Protostrongylidae: Elaphostrongylinae) in Dall’s Sheep from the Mackenzie Mountains, Canada

We demonstrate polymorphism in the structure of the tail among first-stage larvae of Parelaphostrongylus odocoilei (Protostrongylidae). Two distinct larvae, both with a characteristic dorsal spine, include (1) a morphotype with a kinked conical tail marked by three distinct transverse folds or joints and a symmetrical terminal tail spike and (2) a morphotype with a digitate terminal region lacking folds or joints and with an asymmetrical, subterminal tail spike. These divergent larval forms had been postulated as perhaps representing distinct species of elaphostrongyline nematodes. Application of a multilocus approach using ITS-2 sequences from the nuclear genome and COX-II sequences from the mitochondrial genome confirmed the identity of these larvae as P. odocoilei. Additionally, based on scanning electron microscopy (low-temperature field emission), the cephalic region of these larvae consisted of a cuticular triradiate stoma surrounded by six single circumoral papillae of the inner circle, ten papillae of the outer circle (four paired and two single), and two lateral amphids. Ours is the first demonstration of structural polymorphism among larval conspecifics in the Metastrongyloidea and Strongylida. The basis for this polymorphism remains undetermined, but such phenomena, if discovered to be more widespread, may contribute to continued confusion in discriminating among first-stage larvae for species, genera, and subfamilies within Protostrongylidae

Investigations of leptospira in small mammalian host species in the Hawaiian islands

Ph.D. University of Hawaii at Manoa 2012.Includes bibliographical references.Considered the most widespread and prevalent of zoonoses, the emergent infectious leptospirosis disease is found throughout tropical regions in particular, with annual mean incidence rates in Hawaii consistently the highest in the United States. As a tropical archipelago with relatively low host and leptospiral diversity, Hawaii represents an exceptional opportunity for investigations in the ecology and evolution of this bacterial pathogen. In an effort to gain a better understanding of disease transmission dynamics and environmental drivers in Hawaii, the studies presented in this dissertation each take a distinct approach to examining the associations between three main components underlying the ecology of leptospirosis across the archipelago; namely, the Leptospira pathogen, animal hosts, and climate. First, I employed a longitudinal dataset of animal infection prevalence from a period of 14 consecutive years across five maintenance host species and three main islands to describe the epizootiological distribution of pathogenic leptospires in Hawaii. In a second study, I combined field biology and molecular lab techniques to characterize the 16S rRNA genetic diversity of Leptospira amongst a community of small mammals in a local rainforest. Finally, Hosmer-Lemeshow goodness-of-fit and Wald assessments of multivariate logistic regression models were used to investigate the association between rainfall and leptospiral animal infection prevalence at multiple spatio-temporal scales. The key findings in this dissertation address evolutionary patterns of host specificity, provide a preliminary examination of leptospiral genetic diversity in host vectors, and show that precipitation is an environmental driver of host infection prevalence at specific spatial and temporal scales. These results shed light on leptospiral transmission dynamics in a tropical region enzootic for the bacterial pathogen, and lay the foundation for an integrated eco-evolutionary model of leptospirosis in Hawaii

Caudal Polymorphism and Cephalic Morphology among First-Stage Larvae of \u3ci\u3eParelaphostrongylus odocoilei\u3c/i\u3e (Protostrongylidae: Elaphostrongylinae) in Dall’s Sheep from the Mackenzie Mountains, Canada

We demonstrate polymorphism in the structure of the tail among first-stage larvae of Parelaphostrongylus odocoilei (Protostrongylidae). Two distinct larvae, both with a characteristic dorsal spine, include (1) a morphotype with a kinked conical tail marked by three distinct transverse folds or joints and a symmetrical terminal tail spike and (2) a morphotype with a digitate terminal region lacking folds or joints and with an asymmetrical, subterminal tail spike. These divergent larval forms had been postulated as perhaps representing distinct species of elaphostrongyline nematodes. Application of a multilocus approach using ITS-2 sequences from the nuclear genome and COX-II sequences from the mitochondrial genome confirmed the identity of these larvae as P. odocoilei. Additionally, based on scanning electron microscopy (low-temperature field emission), the cephalic region of these larvae consisted of a cuticular triradiate stoma surrounded by six single circumoral papillae of the inner circle, ten papillae of the outer circle (four paired and two single), and two lateral amphids. Ours is the first demonstration of structural polymorphism among larval conspecifics in the Metastrongyloidea and Strongylida. The basis for this polymorphism remains undetermined, but such phenomena, if discovered to be more widespread, may contribute to continued confusion in discriminating among first-stage larvae for species, genera, and subfamilies within Protostrongylidae

Human-Associated \u3cem\u3eBacteroides\u3c/em\u3e spp. and Human Polyomaviruses as Microbial Source Tracking Markers in Hawaii

Identification of sources of fecal contaminants is needed to (i) determine the health risk associated with recreational water use and (ii) implement appropriate management practices to mitigate this risk and protect the environment. This study evaluated human-associated Bacteroides spp. (HF183TaqMan) and human polyomavirus (HPyV) markers for host sensitivity and specificity using human and animal fecal samples collected in Hawaii. The decay rates of those markers and indicator bacteria were identified in marine and freshwater microcosms exposed and not exposed to sunlight, followed by field testing of the usability of the molecular markers. Both markers were strongly associated with sewage, although the cross-reactivity of the HF183TaqMan (also present in 82% of canine [n = 11], 30% of mongoose [n = 10], and 10% of feline [n = 10] samples) needs to be considered. Concentrations of HF183TaqMan in human fecal samples exceeded those in cross-reactive animals at least 1,000-fold. In the absence of sunlight, the decay rates of both markers were comparable to the die-off rates of enterococci in experimental freshwater and marine water microcosms. However, in sunlight, the decay rates of both markers were significantly lower than the decay rate of enterococci. While both markers have their individual limitations in terms of sensitivity and specificity, these limitations can be mitigated by using both markers simultaneously; ergo, this study supports the concurrent use of HF183TaqMan and HPyV markers for the detection of sewage contamination in coastal and inland waters in Hawaii. IMPORTANCE: This study represents an in-depth characterization of microbial source tracking (MST) markers in Hawaii. The distribution and concentrations of HF183TaqMan and HPyV markers in human and animal fecal samples and in wastewater, coupled with decay data obtained from sunlight-exposed and unexposed microcosms, support the concurrent application of HF183TaqMan and HPyV markers for sewage contamination detection in Hawaii waters. Both markers are more conservative and more specific markers of sewage than fecal indicator bacteria (enterococci and Escherichia coli). Analysis of HF183TaqMan (or newer derivatives) is recommended for inclusion in future epidemiological studies concerned with beach water quality, while better concentration techniques are needed for HPyV. Such epidemiological studies can be used to develop new recreational water quality criteria, which will provide direct information on the absence or presence of sewage contamination in water samples as well as reliable measurements of the risk of waterborne disease transmission to swimmers