Hopland Research and Extension Center
University of California
Hopland Research and Extension Center

Entomology, Parasitology, and Public Health

#67-84 “Tick-borne Disease Agents in the Pacific Coast”

Robert S. Lane, Dept. of Environmental Science, Policy, & Management, UC Berkeley

past 67-84 HREC
Following the initial discovery of the causative agent of Lyme Disease in a tick collected at Hopland in 1984, subsequent research defined the unique cycle of this disease on the West Coast.  Here, the spirochete bacteria Borrelia burgdorferi sensu stricto is reservoired primarily in the western gray squirrel (Sciurus griseus) and in other rodents.  Humans and other victim acquire the disease when bitten by the western black-legged tick, Ixodes pacificus.  Recent research investigated the host-seeking behavior of I. pacificus nymphs in relation to environmental parameters and to risk of human exposure.  Previous research established that dense woodlands are primary biotopes of I. pacificus nymphs, and that contact with either leaf litter and wood, but especially wood (e.g., logs), can elevate the risk of human exposure.

#65-86 “Lizard Malaria Host Parasite Ecology”

Joseph H. Schall, Dept. of Biology, University of Vermont
Anne Vardo-Zalik, Penn State University-York

past 65-86 HREC
Since the 1980s, studies of a malarial parasite, Plasmodium mexicanum, that infects western fence lizards Sceloporus occidentalis have focused on understanding the life cycle and the genetics of this parasitic organism, which is a useful model for malarial parasites that are a major human health problem in tropical climates.  At Hopland, the insect vectors of this disease are two species of sand flies (Lutzomyia spp.) that live in the burrows of California ground squirrels (Otospermophilus beecheyi), emerging at night during spring and summer to take blood meals from lizards.  These sand flies are also known to be vectors of visceral Leishmania parasites in South America and in dogs in the U.S.  Recent field research efforts have included investigations of how the lizard’s immune system responds to malaria infection.  This work has importance for both veterinary and human health, especially as climate changes alter the geographic range and behavior of biting insects.

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