Transovarial passage of borreliae -Lyme disease
From: JWissmille (jwissmille_at_aol.com)
Date: 09/17/04
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Date: 17 Sep 2004 01:30:02 GMT
".................. The borreliae received transovarially to larvae of the 1st
generation then were transmitted to 100% nymphs and imago of this generation
and two next generations......."
[Transovarial and transphasic transmissions of Borrelia by the taiga tick
Ixodes persulcatus (Ixodidae)].
[Article in Russian]
Balashov IS, Amosova LI, Grigor'eva LA
Three generations of the taiga tick Ixodes persulcatus, the descendants from
naturally infected females, have been examined by means of dark field and
phase
contrast microscopies and indirect immunofluorescent reactions with monoclonal
antibodies. Location of borreliae in oocytes was examined by means of electron
microscopy. The examined ticks derived from 9 females collected in the
Novgorod
Province, from 6 females of 1st laboratory generation and 5 females of the 2nd
generation. In total, 250 larvae, 178 nymphs, 59 females and 70 males of three
consequent generation have been examined. Almost 100% of descendants of
naturally infected females were infected with Borrelia burgdorferi s. l.[sensu
lato] and similar infection rate was observed in unfed tick larvae collected
in
field conditions. The borreliae received transovarially to larvae of the 1st
generation then were transmitted to 100% nymphs and imago of this generation
and two next generations.
PMID: 10188171
_______________________________
"....... 15.6% of clusters of unengorged larvae harbored B. burgdorferi,
suggesting transovarial passage of the spirochete......"
Comparison of rates of infection by the Lyme disease spirochete in selected
populations of Ixodes dammini and Amblyomma americanum (Acari: Ixodidae).
Zentralbl Bakteriol Mikrobiol Hyg [A] 1986 Dec;263(1-2):72-8 (ISSN:
0176-6724)
Schulze TL; Lakat MF; Parkin WE; Shisler JK; Charette DJ; Bosler EM
At a major endemic focus in New Jersey, 50% of 290 adult Ixodes dammini
collected in the fall of 1984 were infected with the Lyme disease spirochete
(Borrelia burgdorferi), which was statistically higher than the rate found in
the 202 adult ticks (39.6%) examined during the spring. Neither sex nor site
of
collection within the focus significantly affected the infection rate. The
observed infection rates were similar to those reported in endemic areas of
New
York and Connecticut. Borrelia burgdorferi also infected all active stages of
Amblyomma americanum ticks. Rates of infection were 5.4% in adults (n = 467)
and 3.4% in nymphs (n = 289); 15.6% of clusters of unengorged larvae harbored
B. burgdorferi, suggesting transovarial passage of the spirochete. Comparison
of the rates of infection in I. dammini and A. americanum and their potential
impact on Lyme disease transmission is discussed.
Indexing Check Tags: Comparative Study; Female; Male
Language: English
MEDLINE Indexing Date: 198706
Publication Type: Owner: NLM
Publication Type: Journal Article
PreMedline Identifier: 0003577494
Journal Code:
_________________________________________________
Science, June 11, 1993 v260 n5114 p1610(7)
The biological and social phenomenon of Lyme disease. Alan G. Barbour;
Durland Fish.
Author's Abstract: COPYRIGHT American Association for the Advancement of
Science 1993
The endemic cycle of B. burgdorferi, and the consequent epidemiology of
Lyme disease, varies among geographic locations. In the southern United
States, immature I. scapularis feeds primarily on lizards, which are
reservoir-incompetent (43). Consequently, nymphal and adult infection
rates are < 1 %, about the expected rate for transovarial passage (44).
Spirochete infection rates are also 1 to 5% in I. pacificus. Although
transovarial passage contributes to this infection rate, it is not
sufficient to explain the maintenance of endemic foci in the western
United States (45). A transmission cycle involving I. neotomae and the
dusky-footed woodrat Neotoma fuscipes was found responsible for the
maintenance of endemic foci in California. Because I. neotomae is
host-specific and not anthropophilic, the few larval and nymphal I.
pacificus that feed on reservoir-competent mammals rather than lizards
are
responsible for transmitting B. burgdorferi to humans (33, 46).
_______________________________________
Source: Eur J Clin Microbiology Infect Dis (2001) 20:1-5
Editorial
Arthropod-Borne Spirochetosis: A Historical Perspective
W. Burgdorfer
...........
"Koch's work with spirochetes came to an end in 1904, when he was called
to East Africa to investigate the widely distributed East Coast Fever in
cattle. He soon learned that most Europeans traveling the caravan routes
leading from the coast into the intrior regions had been suffering from
relapsing fever, which was first though to be malalria. The African tampan
Ornithodooros moubata, a soft-shelled tick, was incriminated as the
transmitting vector. Koch established the susceptibility of monkeys to the
spirochete and also found that infected female ticks may transmit the
spirochetes to their progeny (transovarial transmission) [6].
___________________________________________________
Clin Microbiol. 2003 Dec;41(12):5557-62. Related Articles, Links
Evidence of Borrelia lonestari DNA in Amblyomma americanum (Acari:
Ixodidae) removed from humans.
Stromdahl EY, Williamson PC, Kollars TM Jr, Evans SR, Barry RK,
Vince MA, Dobbs NA.
Entomological Sciences Program, U.S. Army Center for Health
Promotion and Preventive Medicine, Aberdeen Proving Ground, Maryland
21010-5403, USA. Ellen.Stromdahl@apg.amedd.army.mil
We used a nested PCR with Borrelia flagellin gene (flaB) primers
and DNA sequencing to determine if Borrelia lonestari was present in
Amblyomma americanum ticks removed from military personnel and sent to
the Tick-Borne Disease Laboratory of the U.S. Army Center for Health
Promotion and Preventive Medicine. In our preliminary investigation,
we detected Borrelia sequences in 19 of 510 A. americanum adults and
nymphs from Ft. A. P. Hill, Va. During the 2001 tick season, the flaB
primers were used to test all A. americanum samples as they were
received, and 29 of 2,358 A. americanum samples tested individually or
in small pools were positive. PCRs with 2,146 A. americanum samples in
2002 yielded 26 more Borrelia-positive samples. The positive ticks in
2001 and 2002 were from Arkansas, Delaware, Kansas, Kentucky,
Maryland, New Jersey, North Carolina, Tennessee, and Virginia. The
last positive sample of the 2001 season was a pool of larvae. To
further investigate larval infection, we collected and tested questing
A. americanum larvae from Aberdeen Proving Ground, Md.; 4 of 33 pools
(40 larvae per pool) were positive. Infection of unfed larvae provides
evidence of the maintenance of B. lonestari by means of transovarial
transmission. Sequence analysis revealed that the amplicons were
identical to sequences of the B. lonestari flaB gene in GenBank.
Despite the low prevalence of infection, the risk of B. lonestari
transmission may be magnified because A. americanum is often abundant
and aggressive, and many tick bite victims receive multiple bites.
PMID: 14662940 [PubMed - in process]
___________________________________________________
Soft bodies ticks - relapsing fever
>From Mandell, Douglas and Bennett's Principles and Practice of
Infectious
Diseases Fourth Edition
Borrelia Species (Relapsing Fever)
Warren D. Johnson, Jr.
Tick borne relapsing fever is caused by at least 15 Borrelia spp. and
is
transmitted to man by soft ticks of the genus Ornithodoros. Many
rodents and
small animals serve as natural resovoirs for these borreliae
(chipmunks,
suirrels, rabbits, rats, mice, owls, lizards) ...Transovarial passage
of
borreliae to the tick progeny is an important mechanism for
perpetuation of
the spirochete, because ticks can survive for up to 15 years without
feeding........"
_____________________________________
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