Neorickettsia are bacterial endosymbionts of Digenea (=endoparasitic flukes) capable of infecting the vertebrate hosts of flukes. In humans, N. sennetsu has been identified as a probable cause of unexplained, incapacitating fevers in Laos and Thailand - a region where people routinely eat raw fish and may ingest fluke parasites harboring the bacteria. There are many gaps in our knowledge about Neorickettsia and this proposal seeks to fill some of those gaps. Objectives are three-fold. First, vector incrimination studies will be conducted in N. sennetsu endemic areas of Laos to determine which of the several fluke species that parasitize the people living in the Mekong River basin harbor N. sennetsu and thus are likely vectors of N. sennetsu. Identification of the key vector fluke species involved in sennetsu transmission is a critical step towards establishing risk factors of the disease and in formulating strategies and recommendations for its prevention. Second, a large-scale screening of banked specimens of human digenean parasites, including schistosomes, will be conducted to determine the taxonomic and geographic distribution of Neorickettsia among medically important digenean species. Third, the role of horizontal and vertical transmission will be examined using a non-pathogenic species of Neorickettsia to determine how uninfected fluke lineages acquire the endosymbiont. This project will utilize undergraduate and graduate students to conduct fundamental studies on a little-studied, but potentially widespread bacterial disease agent of humans and their domestic animals.

Public Health Relevance

Neorickettsia are bacterial endosymbionts of parasitic flukes capable of infecting the vertebrate host of the fluke and causing neorickettsial disease. Neorickettsiosis is a little-studied but potentially wide-spread disease associated with digenean parasitism of humans. Understanding its prevalence and mode of transmission will determine the severity and range of this infection and increase the awareness of neorickettsiosis as a probable cause of unexplained febrile illnesses. Correct recognition and diagnosis of neorickettsioses can lead to correct treatment (i.e., doxycycline) and relief of patient suffering.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Academic Research Enhancement Awards (AREA) (R15)
Project #
1R15AI092622-01
Application #
8038833
Study Section
Vector Biology Study Section (VB)
Program Officer
Perdue, Samuel S
Project Start
2011-01-15
Project End
2014-12-31
Budget Start
2011-01-15
Budget End
2014-12-31
Support Year
1
Fiscal Year
2011
Total Cost
$414,000
Indirect Cost
Name
University of North Dakota
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
102280781
City
Grand Forks
State
ND
Country
United States
Zip Code
58202
Greiman, Stephen E; Vaughan, Jefferson A; Elmahy, Rasha et al. (2017) Real-time PCR detection and phylogenetic relationships of Neorickettsia spp. in digeneans from Egypt, Philippines, Thailand, Vietnam and the United States. Parasitol Int 66:1003-1007
Voronova, A N; Chelomina, G N; Besprozvannykh, V V et al. (2017) Genetic divergence of human pathogens Nanophyetus spp. (Trematoda: Troglotrematidae) on the opposite sides of the Pacific Rim. Parasitology 144:601-612
Fischer, Kerstin; Tkach, Vasyl V; Curtis, Kurt C et al. (2017) Ultrastructure and localization of Neorickettsia in adult digenean trematodes provides novel insights into helminth-endobacteria interaction. Parasit Vectors 10:177
Greiman, Stephen E; Rikihisa, Yasuko; Cain, Jacob et al. (2016) Germs within Worms: Localization of Neorickettsia sp. within Life Cycle Stages of the Digenean Plagiorchis elegans. Appl Environ Microbiol 82:2356-2362
Greiman, Stephen E; Kent, Michael L; Betts, John et al. (2016) Nanophyetus salmincola, vector of the salmon poisoning disease agent Neorickettsia helminthoeca, harbors a second pathogenic Neorickettsia species. Vet Parasitol 229:107-109
Greiman, Stephen E; Tkach, Maksym; Vaughan, Jefferson A et al. (2015) Laboratory maintenance of the bacterial endosymbiont, Neorickettsia sp., through the life cycle of a digenean, Plagiorchis elegans. Exp Parasitol 157:78-83
Uhrig, Emily J; Spagnoli, Sean T; Tkach, Vasyl V et al. (2015) Alaria mesocercariae in the tails of red-sided garter snakes: evidence for parasite-mediated caudectomy. Parasitol Res 114:4451-61
Greiman, Stephen E; Tkach, Vasyl V; Pulis, Eric et al. (2014) Large scale screening of digeneans for Neorickettsia endosymbionts using real-time PCR reveals new Neorickettsia genotypes, host associations and geographic records. PLoS One 9:e98453
Greani, Samuel; Quilichini, Yann; Foata, Joséphine et al. (2014) Vitellogenesis of the digenean Plagiorchis elegans (Rudolphi, 1802) (Plagiorchioidea, Plagiorchiidae). Parasitol Int 63:537-43
Greiman, Stephen E; Tkach, Vasyl V; Vaughan, Jefferson A (2013) Transmission rates of the bacterial endosymbiont, Neorickettsia risticii, during the asexual reproduction phase of its digenean host, Plagiorchis elegans, within naturally infected lymnaeid snails. Parasit Vectors 6:303

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