Gastrointestinal Strongyles in Wild Ruminants

Parasitologists have long studied helminth infections in wildlife species and have documented the existence of many organisms from a diversity of mammalian hosts. With this accumulation of information has come improved understanding of the significance of these organisms and the diseases they produce in their mammalian hosts. Some of the most notable examples include the metastrongyloid lungworms, Trichinella spiralis, and Elaeophora schneideri, which are covered separately in this volume. It is, however, for the group of parasites referred to as gastrointestinal nematodes that we have accumulated the most data. Only recently has progress been made in determining the significance of these strongylate nematodes with respect to their potential impact on the morbidity and mortality of the ruminants that they infect. The accumulation of information on diseases of wild animals into a single combined volume has been slow, but progress has coincided with the proliferation of data for host and parasite interactions. Numerous references including Alaskan Wildlife Diseases (Dieterich 1981), Manual of Common Wildlife Diseases in Colorado (Adrian 1981), Field Manual of Wildlife Diseases in the Southeastern United States (Davidson and Nettles 1988), Zoo and Wildlife Medicine (Fowler 1993), and the previous editions of Parasitic Diseases of Wild Mammals (Davis and Anderson 1971) have all made significant contributions to our knowledge. Beyond North America, Dunn (1969) and Govorka et al. (1988) provided excellent compilations on the helminths in wild ruminants. In the 1971 printing of Parasitic Diseases of Mammals, however, there was no general coverage of gastrointestinal nematodes, and only T. spiralis was addressed. Herein, we present the first synoptic review of the strongylate nematodes that occur in the gastrointestinal system of wild ruminants from North America

Insights into the development of Ixodes scapularis: a resource for research on a medically important tick species

Ticks (Acari: Ixodida) are arthropod ectoparasites dependent on a bloodmeal from a vertebrate host at each developmental stage for completion of their life cycle. This tick feeding cycle impacts animal health by causing damage to hides, secondary infections, immune reactions and diseases caused by transmission of pathogens. The genus Ixodes includes several medically important species that vector diseases, including granulocytic anaplasmosis and Lyme disease. I. scapularis, commonly called the black-legged or deer tick, is a medically-important tick species in North America and therefore was the first tick genome to be sequenced, thus serving as an important resource for tick research. This Primer focuses on the normal developmental cycle and laboratory rearing of I. scapularis. Definition of normal morphology, along with a consistent source of laboratory-reared I. scapularis, are fundamental for all aspects of future research, especially the effects of genetic manipulation and the evaluation of tick vaccine efficacy. Recent research important for the advancement of tick research, namely the development of tick cell culture systems for study of ticks and tick-borne pathogens, RNA interference for genetic manipulation of ticks and discovery of candidate antigens for development of tick vaccines, are briefly presented along with areas to target for future research.The preparation of this chapter was partially supported by the EU FP7 ANTIGONE project number 278976, and the Walter R. Sitlington Endowed Chair for Food Animal Research to K.M. Kocan.Peer Reviewe

Polychlorinated Biphenyls and Their Hydroxylated Metabolites (OH-PCBs) in Pregnant Women from Eastern Slovakia

OBJECTIVE: Our aim in the present study was to characterize and quantify the levels of polychlorinated biphenyls (PCBs) and specific polychlorobiphenylol (OH-PCB) metabolites in maternal sera from women delivering in eastern Slovakia. DESIGN: During 2002–2004, blood samples were collected from women delivering in two Slovak locations: Michalovce district, where PCBs were formerly manufactured, and Svidnik and Stropkov districts, about 70 km north. PARTICIPANTS: A total of 762 and 341 pregnant women were sampled from Michalovce and Svidnik/Stropkov, respectively, and OH-PCBs were measured in 131 and 31. EVALUATION/MEASUREMENTS: We analyzed PCBs using gas chromatography (GC)/electron capture detection. OH-PCBs and pentachlorophenol (PCP) were determined as methyl derivatives using GC-electron capture negative ionization/mass spectrometry. We characterized distributions in the full cohort using inverse sampling weights. RESULTS: The concentrations of both PCBs and OH-PCB metabolites of Michalovce mothers were about two times higher than those of the Svidnik/Stropkov mothers (p < 0.001). The median weighted maternal serum levels of the sum of PCBs (∑PCBs) were 5.73 ng/g wet weight (Michalovce) and 2.82 ng/g wet weight (Svidnik/Stropkov). The median sum of OH-PCBs (∑OH-PCBs) was 0.55 ng/g wet weight in Michalovce mothers and 0.32 ng/g wet weight in Svidnik/Stropkov mothers. 4-OH-2,2′ ,3,4′ ,5,5′ ,6-Heptachlorobiphenyl (4-OH-CB187) was a primary metabolite, followed by 4-OH-2,2′ ,3,4′ ,5,5′ -hexachlorobiphenyl (4-OH-CB146). Only four PCB congeners—CBs 153, 138, 180, and 170—had higher concentrations than 4-OH-CB187 and 4-OH-CB146 (p < 0.001). The median ratio of the ∑OH-PCBs to the ∑PCBs was 0.10. CONCLUSIONS: Mothers residing in eastern Slovakia are still highly exposed to PCBs, and their body burdens of these pollutants and OH-PCB metabolites may pose a risk for adverse effects on health for themselves and their children

Naturally occurring Ehrlichia chaffeensis infection in coyotes from Oklahoma.

A nested polymerase chain reaction assay was used to determine the presence of Ehrlichia chaffeensis, E. canis, and E. ewingii DNA in blood samples of free-ranging coyotes from central and northcentral Oklahoma. Of the 21 coyotes examined, 15 (71%) were positive for E. chaffeensis DNA; none was positive for E. canis or E. ewingii. Results suggest that E. chaffeensis infections are common in free-ranging coyotes in Oklahoma and that these wild canids could play a role in the epidemiology of human monocytotropic ehrlichiosis

Infection with Anaplasma phagocytophilum in a seronegative patient in Sicily, Italy: Case Report

BACKGROUND: Anaplasma phagocytophilum causes human granulocytic anaplasmosis (HGA) in humans, which has been recognized as an emerging tick-borne disease in the United States and Europe. Although about 65 cases of HGA have been reported in Europe, some of them do not fulfill the criteria for confirmed HGA. Confirmation of HGA requires A. phagocytophilum isolation from blood, and/or identification of morulae in granulocytes and/or positive PCR results with subsequent sequencing of the amplicons to demonstrate specific rickettsial DNA. Seroconversion or at least fourfold increase in antibody titers to A. phagocytophilum has been used as criteria for confirmed HGA also. CASE PRESENTATION: Infection with A. phagocytophilum was confirmed by PCR in a patient in Sicily, Italy, who had negative serology for A. phagocytophilum. A fragment of A. phagocytophilum 16S rDNA was amplified by two independent laboratories and sequenced from two separate patient's blood samples. The 16S rDNA sequence was identical in both samples and identical to the sequence of the A. phagocytophilum strain USG3 originally obtained from a dog. CONCLUSION: Infection with A. phagocytophilum was confirmed in a patient without a detectable antibody response against the pathogen. The results reported herein documented the first case of confirmed HGA in Sicily, Italy. These results suggested the possibility of human infections with A. phagocytophilum strains that result in clinical symptoms and laboratory findings confirmatory of HGA but without detectable antibodies against the pathogen

Silencing of genes involved in Anaplasma marginale-tick interactions affects the pathogen developmental cycle in Dermacentor variabilis

<p>Abstract</p> <p>Background</p> <p>The cattle pathogen, <it>Anaplasma marginale</it>, undergoes a developmental cycle in ticks that begins in gut cells. Transmission to cattle occurs from salivary glands during a second tick feeding. At each site of development two forms of <it>A. marginale </it>(reticulated and dense) occur within a parasitophorous vacuole in the host cell cytoplasm. However, the role of tick genes in pathogen development is unknown. Four genes, found in previous studies to be differentially expressed in <it>Dermacentor variabilis </it>ticks in response to infection with <it>A. marginale</it>, were silenced by RNA interference (RNAi) to determine the effect of silencing on the <it>A. marginale </it>developmental cycle. These four genes encoded for putative glutathione S-transferase (GST), salivary selenoprotein M (SelM), H+ transporting lysosomal vacuolar proton pump (vATPase) and subolesin.</p> <p>Results</p> <p>The impact of gene knockdown on <it>A. marginale </it>tick infections, both after acquiring infection and after a second transmission feeding, was determined and studied by light microscopy. Silencing of these genes had a different impact on <it>A. marginale </it>development in different tick tissues by affecting infection levels, the densities of colonies containing reticulated or dense forms and tissue morphology. Salivary gland infections were not seen in any of the gene-silenced ticks, raising the question of whether these ticks were able to transmit the pathogen.</p> <p>Conclusion</p> <p>The results of this RNAi and light microscopic analyses of tick tissues infected with <it>A. marginale </it>after the silencing of genes functionally important for pathogen development suggest a role for these molecules during pathogen life cycle in ticks.</p