Ixodes Ricinus as a potential vector of toxoplasma gondhi

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Ixodes Ricinus as a potential vector of toxoplasma gondhi

Post by Yvonne » Sun 6 Sep 2009 12:59


The presence of Toxoplasma gondii DNA was detected by polymerase chain
reaction (PCR) test in 2 out of 92 Ixodes ricinus ticks (2.8%) collected in the woodlands
of eastern Poland. This suggests that ticks of this species may be involved in the spread
of toxoplasmosis under natural conditions

Toxoplasmosis, caused by parasitic protozoan Toxoplasma
gondii, is an usually asymptomatic zoonotic disease common
in man and over 100 species of mammals and birds. In
humans, toxoplasmosis may pose a severe medical problem
as a congenital infection causing cerebral and ocular
damage in newborns, and as an acquired infection in
immunocomprised individuals, such as AIDS patients [5, 8].
The sexual reproduction of the parasites has been
observed until recently only in intestine of felids. Oral
transmission, by consumption of raw meat or food contaminated
with cat feces containing T. gondii oocysts, is
regarded as the only route of primary infection. However,
this route hardly explains the common occurrence of T.
gondii in variety of hosts, such as herbivorous mammals,
wild rodents and birds that are unlikely to contract primary
infection orally with meat or cat feces. Thus, some
additional routes of transmission suggested by earlier
authors should be also considered, including infection by
skin lesions, and transmission by arthropods [3, 7, 9, 13, 19].
The possible role of arthropods in transmission of
Toxoplasma is discussed with respect to passive spreading
by flies and cockroaches [13], and to active transmission
by blood-sucking insects and arachnids. Of the latter
most concern was directed towards ticks (Ixodida) as
potential vectors of infection in man and warm-blooded
animals. Cases of human toxoplasmosis associated with
tick bite were described [2, 14, 15], Toxoplasma strains
were isolated from naturally infected ticks [3, 9, 11, 15], and
possibility of experimental transmission of infection by
various tick species was evidenced [6, 7, 19]. 'HU\áRet al.
[7] have demonstrated experimentally the transmission of
Toxoplasma gondii infection by nymphs of Ixodes ricinus and
found microscopically the presence of T. gondii tachyzoites
and bradyzoites in the tissues of nymphs and females.
Based on above-mentioned findings, we have examined
Ixodes ricinus ticks collected from the natural habitats in
eastern Poland for the presence of T. gondii with the use
polymerase chain reaction (PCR

Detection of the Toxoplasma gondii DNA in Ixodes
ricinus ticks suggests a possibility of tick transmission as
a new way of spreading this parasite in nature. This confirms
earlier reports [2, 3, 6, 7, 9, 11, 15, 19] indicating ticks as
potential vectors of toxoplasmosis.
Ixodes ricinus is the most common tick species in
Europe [16]. Thus, the ability of transmission of T. gondii
by this species would be of significant epidemiological
importance. This could explain, at least in part, the high
incidence of seropositive reactions in direct agglutination
test for toxoplamosis (68.6%) found by Sroka [17] among
forestry workers in the Sobibór area. This author has also
described a case of clinical toxoplasmosis in a forester
from this area [17]. A high, exceeding 50%, prevalence of
anti-Toxoplasma antibodies among cows in eastern Poland
[17] seems to indicate that besides the oral route of T.
gondii infection, an additional route of infection should be
considered, possibly by tick-borne transmission. I. ricinus
ticks are common in woodlands of eastern Poland where
they play an important epidemiological role as vectors of
Lyme borreliosis and tick-borne encephalitis [4].
So far, our hypothesis on the possible role of ticks in
epidemiology of toxoplasmosis must be regarded with some
caution, as some authors were not successful in isolation
of T. gondii from ticks collected in natural habitats or in
experimental transmission of the infection by these arachnids
[1, 10, 12]. Also, it is unknown which stage(s) of Ixodes
ricinus might be involved in the transmission of T. gondii
and how the life cycle of parasites looks in the tick body.
In this work, T. gondii DNA was found only in the adult
female ticks but in an earlier study 'HU\áR et al. [7]
evidenced the transmission of Toxoplasma by intermittent
blood sucking of I. ricinus nymphs, but not larvae and
females. However, in the present work, no nymphs were
found in the locality where infected I. ricinus females were
collected. Thus, further studies are needed for elucidation
of all the questions concerning possible transmission of
Toxoplasma gondii by Ixodes ricinus ticks
Listen to all,
plucking a feather from every passing goose,
but follow no one absolutely

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Re: Ixodes Ricinus as a potential vector of toxoplasma gondhi

Post by Yvonne » Sun 7 Feb 2010 11:00

The occurence of Toxoplasma gondii and Bb sensu lato in ixodes ricinus ticks from eastern Poland with the use of PCR :

Listen to all,
plucking a feather from every passing goose,
but follow no one absolutely

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