All Posts Tagged With: "ticks"

Link: http://www.ajtmh.org/cgi/content/full/79/6/971

Excerpt:

These findings suggest that deer tick-borne POWV may present a public health risk to human residents of and visitors to infested sites. 
Paradoxically, despite the apparent increase in the incidence of human infection, the proportion of ticks infected remained constant between the 1990s and the present. 
The increased geographic distribution of deer ticks and concomitant increases in their populations might produce a greater number of infected ticks overall, or might facilitate spillover from cryptic enzootic foci, which might produce additional human POWV infections. 

It may be that a proportion of the recent increase in the recognition of POWV encephalitis in North America is attributable to the emergence of DTV. 
Ongoing studies will therefore more completely characterize the transmission cycle and molecular epidemiology of DTV within this focus. 

Importantly, infection by viruses within the TBE serologic complex results in a wide range of clinical outcomes, ranging from asymptomatic to severe: DTV may be less pathogenic than prototypical POWV, as has been suggested previously. 

Experimental studies are required to evaluate this hypothesis. In the absence of this data, clinicians should consider tick-borne flavivirus infection in patients presenting 1) with neurologic symptoms and 2) residence or travel to tick-infested sites.

Link: http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=20711724&retmode=ref&cmd=prlinks

Excerpt:

An increasing number of studies reveal that ticks and their hosts
are infected with multiple pathogens, suggesting that coinfection
might be frequent for both vectors and wild reservoir hosts.
Whereas the examination of associations between coinfecting
pathogen agents in natural host-vector-pathogen systems is a
prerequisite for a better understanding of disease maintenance
and transmission, the associations between pathogens within
vectors or hosts are seldom explicitly examined. We examined the
prevalence of pathogen agents and the patterns of associations
between them under natural conditions, using a previously
unexamined host-vector-pathogen system-green lizards Lacerta
viridis, hard ticks Ixodes ricinus, and Borrelia, Anaplasma, and
Rickettsia pathogens. We found that immature ticks infesting a
temperate lizard species in Central Europe were infected with
multiple pathogens. Considering I. ricinus nymphs and larvae, the
prevalence of Anaplasma, Borrelia, and Rickettsia was 13.1% and
8.7%, 12.8% and 1.3%, and 4.5% and 2.7%, respectively. The
patterns of pathogen prevalence and observed coinfection rates
suggest that the risk of tick infection with one pathogen is not
independent of other pathogens. Our results indicate that
Anaplasma can play a role in suppressing the transmission of
Borrelia to tick vectors. Overall, however, positive effects of
Borrelia on Anaplasma seem to prevail as judged by
higher-than-expected Borrelia-Anaplasma coinfection rates.

Article:

Excerpt:

To determine whether and which spirochetes are cleared from
Ixodes ricinus ticks while feeding on ruminants, ticks were
removed from goats and cattle grazing on tick-infested pastures.
Al-though about a quarter of ticks questing on the pasture was
infected by spirochetes, no molted ticks that had previously
engorged to repletion on ruminants harbored Lyme disease
spirochetes. Ixodes ricinus ticks, however, appear not
to be eliminated. Thus, the more subadult ticks are diverted from
reservoir competent hosts to zooprophylactic ruminants, the
smaller the risk of infection by Lyme disease spirochetes.

Full article: http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=20846013&retmode=ref&cmd=prlinks

Excerpt:

Abstract From May until October 2007, a total of 658 Ixodes
ricinus ticks were collected off birds (189), rodents (273), and
vegetation (196) in a certain area of Middle Germany and
investigated for infection with Babesia spp., Anaplasma
phagocytophilum, and Rickettsia spp. Overall, 13.1% (86/658) of
the ticks were infected with at least one pathogen; co-infections
occurred in 0.6% (4/658).
Babesia spp. specific DNA was detected in 9.7% (64/658) of the
ticks, 1.4%
(9/658) were infected with A. phagocytophilum, and 2.6% (17/658)
harbored rickettsiae. At least two different Rickettsia species
were identified:
Rickettsia monacensis and Rickettsia helvetica. Our study
provides first interesting insights into the circulation and
co-circulation of several emerging pathogens not only in ticks
parasitizing birds and small mammals as potential reservoirs but
also in questing ticks in a single natural habitat.

Full article: http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=20842825&retmode=ref&cmd=prlinks

Excerpt:

Lyme borreliosis is a multisystem disease and when involves the
nervous system it is termed neuroborreliosis. The symptomatology
of peripheral neuroborreliosis is rich and varied. The early
symptoms are asymmetric polyradiculopathies and paralysis of the
cranial nerves (most commonly facial nerve). Thereafter, there
are multifocal mononeuropathies and
sensory-motorpolyneuropathies. Difficulties in making a correct
diagnosis can result from the long time lag between tick bite and
the occurrence of neurological symptoms. In the treatment the
most important role play antibiotics. 
CASE REPORTS: We report the cases of three patients with symptoms
of damage to various structures of the peripheral nervous system
in the course of Borrelia burgdorferi infection. In all cases,
clinical improvement was obtained after treatment with
antibiotics, which further confirms the diagnosis of
neuroborreliosis. 
CONCLUSIONS: About neuroborreliosis
as a cause of peripheral neuropathy we should always think in the
case of vague symptoms of peripheral nervous system lesions in
patients with potential exposure to tick bites. Peripheral
neuropathies may occur a long interval from the tick bite and are
not always preceded by other forms of the disease.

Full article: http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=20844223&retmode=ref&cmd=prlinks

Excerpt:

Members of the genus Borrelia are among the most common
infectious agents causing tick-borne disease in humans worldwide.
Here, we developed a Light Upon
eXtension(TM) (LUX) real-time PCR assay that can detect and
quantify Borrelia species in ticks that have fed on humans, and
we applied the assay to 399 such ticks. Borrelia PCR-positive
ticks were identified to species by sequencing the products of
conventional PCR performed using Borrelia group-specific primers.
There was a 19% prevalence of Borrelia spp. in the detached
ticks, and the number of spirochetes per Borrelia PCR-positive
tick ranged from 2.0 x 10(2) to
4.9 x 10(5) with a median of 7.8 x 10(3) spirochetes. Adult ticks
had a significantly larger number of spirochetes with a median of
8.4 x 10(4) compared to the median of nymphs 4.4 x 10(4). Adult
ticks also exhibited higher prevalence of Borrelia (33%) compared
to nymphs (14%). Among the identified species, Borrelia afzelii
was found to predominate (61%), followed by B. garinii (23%), B.
valaisiana (13%), B. burgdorferi sensu stricto (1%), B.
lusitaniae (1%), and B. miyamotoi-like (1%). Also, 3% of the
ticks were co-infected with multiple strains of B. afzelii.
Notably, this is the first report of B.
lusitaniae being detected in ticks in Sweden. 

Full article: http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=20823366&retmode=ref&cmd=prlinks

Excerpt:

RESULTS: B. henselae and related
bacterial species are transmitted among cats and dogs by
arthropod vectors. In the absence of these vectors, disease does
not spread amongst the animals. On the other hand, disease can be
spread to humans by bite and scratch as well as by arthropod
vectors. Animals commonly infected with B. henselae and arthropod
vectors are discussed. 
CONCLUSIONS: Clinicians should be aware that a common illness,
cat scratch disease, can be transmitted by arthropod vectors and
a history of an animal scratch or bite is not necessary for
disease transmission.

Full article: http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=20618664&retmode=ref&cmd=prlinks

Excerpt:

Ixodes affinis, which is similar morphologically to Ixodes
scapularis, is widely distributed in North Carolina. Collections
have documented this species in 32 of
41 coastal plain counties, but no piedmont or mountain counties.
This coastal plain distribution is similar to its distribution in
Georgia and South Carolina, where it is considered an enzootic
vector of Borrelia burgdorferi sensu stricto.
An updated list of hosts for I. affinis in the U.S.A. is
included, increasing the number to 15 mammal and one bird
species. The presence of questing adults of I. affinis from April
to November reinforces the need for confirmed identifications of
suspected tick vectors of Borrelia spirochetes collected during
warm months.

Excerpt:

Lyme disease is reported across Canada, but pinpointing the source of infection has been problematic. In this three-year, bird-tick-pathogen study (2004–2006), 366 ticks representing 12 species were collected from 151 songbirds (31 passerine species/subspecies) at 16 locations Canada-wide. Of the 167 ticks/pools tested, 19 (11.4%) were infected with Borrelia burgdorferi sensu lato (s.l.). Sequencing of the rrf-rrl intergenic spacer gene revealed four Borrelia genotypes: B. burgdorferi sensu stricto (s.s.) and three novel genotypes (BC genotype 1, BC genotype 2, BC genotype 3). All four genotypes were detected in spirochete-infected Ixodes auritulus (females, nymphs, larvae) suggesting this tick species is a vector for B. burgdorferi s.l. We provide first-time records for: ticks in the Yukon (north of 60° latitude), northernmost collection of Amblyomma americanum in North America, and Amblyomma imitator in Canada. First reports of bird-derived ticks infected with B. burgdorferi s.l. include: live culture of spirochetes from Ixodes pacificus (nymph) plus detection in I. auritulus nymphs, Ixodes scapularis in New Brunswick, and an I. scapularis larva in Canada. We provide the first account of B. burgdorferi s. l. in an Ixodes muris tick collected from a songbird anywhere. Congruent with previous data for the American Robin, we suggest that the Common Yellowthroat, Golden-crowned Sparrow, Song Sparrow, and Swainson’s Thrush are reservoir-competent hosts. Song Sparrows, the predominant hosts, were parasitized by I. auritulus harboring all four Borrelia genotypes. Our results show that songbirds import B. burgdorferi s.l.-infected ticks into Canada. Bird-feeding I. scapularis subadults were infected with Lyme spirochetes during both spring and fall migration in eastern Canada. Because songbirds disperse millions of infected ticks across Canada, people and domestic animals contract Lyme disease outside of the known and expected range.

Full article: http://www.news-medical.net/news/20100416/International-experts-discuss-threats-posed-by-ticks-and-fleas.aspx

Excerpt:

As experts from around the world met in New York this week they discussed the need for greater understanding of the threat posed by ticks, fleas and sand flies. Leading scientists called on veterinarians and dog-owners around the world to take action to protect dogs and humans from potentially lethal diseases.

Ticks, mosquitoes, fleas and, in some countries, sand flies are critical in the transmission of diseases to both dogs and humans, including life-threatening conditions such as Lyme Disease, Leishmaniasis and other important diseases such as Ehrlichiosis.