Browsing by Author "Jarvi, Susan I."

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    Addressing angiostrongyliasis on Hawai'i Island with research, education outreach, and host control
    (2016-12) Howe, Mary Kathleen; Jarvi, Susan I.; Tropical Conservation Biology & Environmental Science
    Hawaii Island has the highest incidence of rat lungworm disease (RLWD) of all the Hawaiian Islands and the mainland United States. The relatively recent introduction of the semi-slug Parmarion martensi, an effective intermediate host, and the wide-spread use of rainwater catchment systems may play a role. Studies were designed to investigate the ability of drowned gastropods to shed larvae, the location in a water column where larvae would most likely be found, the potential for larval passage through a 20μm filter, and the ability of the larvae to survive outside the slug/snail host. Whole P. martensi shed many, viable A. cantonensis larvae with >90% of larvae found in samples taken from the bottom of the water column, suggesting they may settle near the bottom of a catchment tank. Larvae that were able to pass through a 20μm sieve could not survive acid, were active for at least 56 days outside the slug host, and tested positive for RLW by qPCR. Larvae that could not pass through a 20μm sieve were able to survive HCl-pepsin, were active for at least 21 days, and tested positive for RLW. First stage larvae can survive gut acid when swallowed after migration from the lungs but cannot withstand acid immersion again until they become third stage larvae.The study results merit further investigation into the potential link between poorly maintained rainwater catchment systems and the high incidence of RLWD on Hawaii Island, and the studies clearly demonstrate the need for control of hosts of Angiostrongylus cantonensis. Hawaii’s remote location makes food security an important issue. State-wide efforts to promote the Grow Local, Eat Local movement are reflected in the growing number of residential gardens, small farms, farmers’ markets, school and youth garden projects, and the recent passage of the Farm to School Bill. However, efforts to educate farmers, food handlers, and consumers about rat lungworm disease and the need for disease prevention and host control has not been similarly supported. In collaboration with five partner schools on Hawaii Island, the University of Hawaii, Daniel K. Inouye College of Pharmacy’s Hawaii Island Rat Lungworm Working Group worked with students and teachers to develop an integrated pest management plan for school garden projects. Integrated pest management allows for the careful consideration of applications available to control a pest event and chooses those practices that are least harmful to human and environmental health. These best practices include preventative cultural practices, monitoring, mechanical control, biological control, and the responsible use of pesticides. Students were intensively educated about RLWD, the parasite’s life cycle, and prevention measures. Using best management practices, we set up traps and collected data on gastropod species abundance, and shelter-type capture rate. Integrating STEM curriculum makes the project attractive to schools as it supports student academic success. Adoption of this management project by the many school and youth garden projects in areas of RLWD can exponentially increase community awareness, encourage control efforts, and potentially map disease risk.
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    Efficacy of a commercial cararypox vaccine for protecting Hawai`i `Amakihi from field isolates of avipoxvirus.
    (2010-09) Atkinson, Carter T.; Wiegand, Kimberly C.; Triglia, Dennis A.; Jarvi, Susan I.
    At least three variants of avian pox virus are present in Hawai’i - Fowlpox from domestic poultry and a group of genetically distinct viruses that cluster within two clades (Pox Variant 1 and Pox Variant 2) that are most similar to Canarypox based on DNA sequence of the virus 4b core protein gene. We tested whether Hawai’i ‘Amakihi can be protected from wild virus isolates with an attenuated live Canarypox vaccine that is closely related to isolates that cluster within clade 1 (Pox Variant 1) based on sequence of the attenuated Canarypox virus 4b core protein. Thirty-one (31) Hawai`i ‘Amakihi (Hemignathus virens) with no prior physical evidence of pox infection were collected on Mauna Kea from xeric, high elevation habitats with low pox prevalence and randomly divided into two groups. One group of 16 was vaccinated with Poximmune C® while the other group received a sham vaccination with virus diluent. Four of 15 (27%) vaccinated birds developed potentially life-threatening disseminated lesions or lesions of unusually long duration, while one bird never developed a vaccine-associated lesion or “take”. After vaccine-associated lesions healed, vaccinated birds were randomly divided into three groups of five and challenged with either a wild isolate of Fowlpox, a Hawai`i `Amakihi isolate of a Canarypox-like virus from clade 1 (Pox Variant 1) or a Hawai`i `Amakihi isolate of a Canarypox-like virus from clade 2 (Pox Variant 2). Similarly, three random groups of five unvaccinated ‘Amakihi were challenged with the same virus isolates. Vaccinated and unvaccinated ‘Amakihi challenged with Fowlpox had transient infections with no clinical signs of infection. Mortality in vaccinated ‘Amakihi that were challenged with Pox Variant 1 and Pox Variant 2 ranged from 0% (0/5) for Pox Variant 1 to 60% (3/5) for Pox Variant 2. Mortality in unvaccinated ‘Amakihi ranged from 40% (2/5) for Pox Variant 1 to 100% (5/5) for Pox Variant 2. While the vaccine provided some protection against Pox Variant 1, serious side effects and low efficacy against Pox Variant 2 make it risky to use in captive or wild honeycreepers.