All Posts Tagged With: "Vector-Borne Infectious Diseases"

Full article: http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=20519614&retmode=ref&cmd=prlinks

Excerpt:

To determine the role of Bartonella species as causes of acute
febrile illness in humans from Thailand, we used a novel strategy
of co-cultivation of blood with eukaryotic cells and subsequent
phylogenetic analysis of Bartonella-specific DNA products.
Bartonella species were identified in 14 blood clots from febrile
patients. Sequence analysis showed that more than one-half of the
genotypes identified in human patients were similar or identical
to homologous sequences identified in rodents from Asia and were
closely related to B. elizabethae, B. rattimassiliensis, and B.
tribocorum. The remaining genotypes belonged to B. henselae, B.
vinsonii, and B. tamiae. Among the positive febrile patients,
animal exposure was common: 36% reported owning either dogs or
cats and 71% reported rat exposure during the 2 weeks before
illness onset. The findings suggest that rodents are likely
reservoirs for a substantial portion of cases of human Bartonella
infections in Thailand.

Excerpt:

In the far-western United States, the nymphal stage of the
western black-legged tick, Ixodes pacificus, has been implicated
as the primary vector to humans of Borrelia burgdorferi sensu
stricto (hereinafter referred to as B. burgdorferi), the
causative agent of Lyme borreliosis in North America. In the
present study, we sought to determine if infection prevalence
with B. burgdorferi in I.
pacificus nymphs and the density of infected nymphs differ
between dense-woodland types within Mendocino County, California,
and to develop and evaluate a spatially-explicit model for
density of infected nymphs in dense woodlands within this
high-incidence area for Lyme borreliosis. In total, 4.9%
(264) of 5431 I. pacificus nymphs tested for the presence of B.
burgdorferi were infected. Among the 78 sampling sites, infection
prevalence ranged from 0 to 22% and density of infected nymphs
from 0 to 2.04 per 100 m(2). Infection prevalence was highest in
woodlands dominated by hardwoods (6.2%) and lowest for redwood
(1.9%) and coastal pine (0%). Density of infected nymphs also was
higher in hardwood-dominated woodlands than in conifer-dominated
ones that included redwood or pine. Our spatial risk model, which
yielded an overall accuracy of 85%, indicated that warmer areas
with less variation between maximum and minimum monthly water
vapor in the air were more likely to include woodlands with
elevated acarological risk of exposure to infected nymphs. We
found that 37% of dense woodlands in the county were predicted to
pose an elevated risk of exposure to infected nymphs, and that
94% of the dense-woodland areas that were predicted to harbor
elevated densities of infected nymphs were located on
privately-owned land.