Stadse teken

[Sproetje]

Ixodes ricinus en zijn overdraagbare ziekteverwekkers in stedelijke en peri-stedelijke gebieden in Europa:
Nieuwe gevaren en relevantie voor de volksgezondheid.


door A Rizzoli
Online gepubliceerd: 1 dec. 2014
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4248671/

"Door teken overgedragen ziekten vormen grote volks en diergezonheids problemen wereldwijd.
Ixodes ricinus, vnl. geassocieerd met loof en gemengde bossen, is de belangrijkste vector van de verwekkers van
virale, bacteriële en protozoaire zoönotische ziekten in Europa.
Onlangs zijn er overvloedige teken populaties waargenomenin Europese stedelijke groene gebieden,
die relevant zijn voor de volksgezondheid als gevolg van de bloodstelling van mensen en gedomesticeerde dieren
met potentieel besmette teken.
In stedelijke habitats, kleine en middelgrote zoogdieren, vogels, gezelschapsdieren en grotere zoogdieren
spelen een rol in het onderhoud van de teken bevolking en als reservoir van de door teken overgedragen pathogenen.
Aanwezigheid van de teken besmet met tekenencefalitis virusen de hoge prevalentie van de teken besmet
met borrelia burgdorferi sl, waardoor lyme borreliose ontstaat, zijn gemeld uit vertedelijkte gebieden in Europa.
Opkomende ziekteverwekkers, zoals bacterién van de Rickettsiales (anaplasma phagocytophilum, candidatus Neoehrlichia mikurensis,
rickettttsia helvetica en R. monacensis), borrelia miyamotoi en protozoa babesia divergens, B venatorum en B microti
werden ook waargenomen in stedelijke teek populaties
Inzicht in de ecologie van teken en hun verenigingen met gastheren in een
Europese verstedelijkte omgeving is cruciaal om de parameters die nodig zijn voor risico-pre-assessment
en overgedragen ziekten te kwantificeren."

Nu hoef je tegenwoordig dus niet meer naar het buitengebied om lyme en co-infecties op te lopen.
Kan gewoon terwijl je via het park nog even snel een boodschapje wilt doen.....

[NMDA]

Interessante publicatie met erg veel relevante informatie.

Maar de volgende publicatie waarin in de andere publicatie naar verwezen werd is ook nogal belangijk:

A case of meningoencephalitis by the relapsing fever spirochaete Borrelia miyamotoi in Europe

On April 1 2012, a 70-year-old patient came to our clinic reporting slow cognitive processing, memory deficits, and a disturbed gait, all of which had gradually developed over several months and progressed during the last few weeks before the patient’s initial visit. He did not report fever, and he had not been outside the country for several years. He had recently been treated with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone), poly chemotherapy, and rituximab (last dose on Aug 2, 2011) for a stage 4 diffuse large B cell lymphoma. His medical history also included Pneumocystis jirovecii pneumonia, un explained chronic diarrhoea, a splenectomy, extensive tick exposure, and two tick bites in the summer and fall before onset of symptoms. On neurological examination there was a distinct bradyphrenia, and on cognitive assessment, the patient scored 26 of 30 points on the mini mental state examination. Vital signs were normal and body temperature was 36·4°C. Cranial MRI showed no abnormalities, but two lumbar punctures showed cerebrospinal fluid pleocytosis with raised protein values. The cause of this chronic meningitis was not identified by wide-ranging micro biological, pathological, and haematological diagnostic testing (appendix). A C6-immunofluorescence assay for Borrelia burgdorferi in serum, but not in cerebrospinal fluid, was weakly positive (index 1·8). However, a B burgdorferi IgG and IgM immunoblot were non-conclusive and negative, respectively. A B burgdorferi sl qPCR in cerebrospinal fluid was negative. Nonetheless, because of the absence of an alternative diagnosis and the progression of symptoms, on April 17, 2012, the patient was treated for a possible Lyme neuroborreliosis with once daily 2000 mg ceftriaxone intravenously for 2 weeks.

Supported by the recent evidence of the presence of B miyamotoi in Ixodes ricinus ticks across Europe,1,2 the relation in time of the patient’s symptoms with the tick bites, and his immunocompromised status, we retrospectively considered B miyamotoi as the causative agent. We identified motile spirochaetes in stored pre-treatment cerebrospinal fluid by dark-field microscopy (appendix). Additionally, a 16S rDNA pan-relapsing fever Borrelia quantitative (q)PCR and a qPCR targeting the B miyamotoi flagellin gene was positive in two separate pre-treatment cerebrospinal fluid samples and one pre-treatment blood sample (appendix). Notably, 2·2% of 352 I ricinus nymphal ticks from the vicinity of the patient’s recreational house in the dunes of Zandvoort, the Netherlands, proved to be positive for B miyamotoi by qPCR (appendix). Amplification and sequencing of the glpQ and p66 genes confirmed B miyamotoi as the causative agent and showed 100% identical sequences in ticks and the patient’s clinical samples

Dus een 70 jarige Nederlander die al jaren niet meer in het buitenland is geweest werd opgenomen met Lyme achtige symptomen. De C6 bloedtest was licht positief en de overige Lyme testen allemaal negatief. Echter werd er toch overgegaan tot een antibiotica behandeling van 2 weken die overigens de klachten bij de patiënt compleet deden verdwijnen.

In zijn hersenvocht werden later met een dark-field microscoop spirocheten waargenomen. Latere PCR testen specifiek voor Borrelia Miyamotoi toonde ook positieve resultaten aan in zijn hersenvocht en bloedmonster. Ook wordt er gerefereerd aan het feit dat er in de buurt van de vakantiewoning van de patiënt in kwestie in duinen van Zandvoort bij 2,2 % van de nymphen schapenteken Borrelia Miyamotoi werd aangetoond met PCR diagnostiek.

Dus ja Borrelia Miyamotoi komt nu officieel ook voor in Nederland en de normale Lyme testen op de C6 test na tonen hem niet aan.

[Sproetje]

Dat Borrelia Miyamotoi niet in Nederland voorkomt kan niet meer gezegd worden.

Borrelia Miyamotoi werd ontdekt in Japan in 1995:

https://sites.google.com/site/drjoneski ... -miyamotoi

Wat die testen betreft, het blijft allemaal een beetje vaagjes eerlijk gezegd.
Zoals ik het had begrepen kan ook een PCR niet altijd 100% zekerheid geven, omdat wanneer
PCR tests gebaseerd zijn op het OspA gen of andere afwijkende Borrelia Miyamotoi genen zal de bacterie niet aangetoond kunnen worden.
De C6 peptide Elisa testen zijn dacht ik ook niet volledig 100% ?
In Europa wordt nogal een lage gevoeligheid gevonden voor deze C6

Daarom ook dat het RIVM samen met J.Hovius een goede test hiervoor wil ontwikkelen, zo had ik gelezen op de site van het RIVM.
Ik hoop dat het een beetje voortgang heeft, ben benieuwd waar ze mee komen....

Hoewel Lee al een gevoelige PCR-sequencing test heeft ontwikkeld die zowel Borrelia Burgdorferi als Borrelia Miyamotoi kan aantonen en waarover al veel studies gepubliceerd zijn........

Ehm, begrijp jij het nog?

[Sproetje]

Nou, het RIVM en J. Hovius hoeven niet meer verder te zoeken hoor, kijk hier maar eens:

DNA Sequencing Diagnosis of Off-Season Spirochetemia with Low Bacterial Density in Borrelia burgdorferi and Borrelia miyamotoi Infections

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4139787/
Door: Sin Hang Lee, Jessica S. Vigliotti, Veronica S. Vigliotti, William Jones, Thomas A. Moorcroft, and Katherine Lantsman
Juli 2014

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1. Introduction

Reliable diagnosis of Lyme disease caused by Borrelia burgdorferi at its early stage of infection is important for the timely implementation of appropriate treatments to prevent tissue damages and to achieve a “cure” of the disease [1]. However, the diagnosis of Lyme disease is primarily based on evaluating the highly variable symptoms, physical findings (e.g., rash), and the possibility of exposure to infected ticks [2,3]. The commonly used 2-tier serology laboratory test which usually only turns positive during convalescence of the infection is reported to be negative or non-diagnostic in 75% of the “clinically confirmed” cases of early Lyme disease [4]. Blood culture at the stage of bacteremia has met only limited success in specialized laboratories and offers little help to the timely management of patients suffering from early Lyme disease bacterial infection due to the slow growth rate of the spirochetes in artificial media [5]. Conventional polymerase chain reaction (PCR) amplification of the bacterial DNA for detection is not sensitive enough for routine diagnostic purpose because the copies of the target DNA extracted from the very low number of spirochetes in the patient blood samples are often below the limit of detection [6,7]. False positive PCR results have also been reported, and may be due to non-specific PCR amplification of irrelevant DNA in the patient samples [8,9]. Using species-specific primers, such as the LD1 and LD2 [10,11], and TEC1 [12] primers to amplify a highly conserved segment of the 16S ribosomal RNA gene DNA (16S rDNA) of B. burgdorferi sensu lato for detection, followed by direct DNA sequencing of the nested PCR amplicon for validation, has been used to provide sensitive and specific molecular diagnosis of Lyme arthritis [13] and early Lyme disease at the spirochetemic stage [14].

Recently, human infections by Borrelia miyamotoi—a spirochete distantly related to B. burgdorferi, but classified in the relapsing fever Borrelia group—have been reported in the United States [15,16]. Since B. miyamotoi is transmitted by the same Ixodes vector as B. burgdorferi sensu stricto [17], and may cause clinical symptoms similar to those of Lyme disease, including skin rashes [18], B. miyamotoi infection should be included in the differential diagnosis of patients presenting with unexplained fever, headache and myalgia with or without skin rash in Lyme disease-endemic areas during the seasons when ticks are active. Molecular assays are the only option to test for B. miyamotoi infection because this spirochete is hard to culture in modified Barbour-Stoenner-Kelly medium and the currently available two-tier serology test offers little help for its diagnosis [15,18].

In this paper, we introduce a pair of common PCR primers for same-nested PCR amplification of a highly conserved segment with hypervariable regions of the 16S rDNA of B. burgdorferi and B. miyamotoi followed by direct DNA sequencing of the PCR amplicon for the molecular diagnosis of these two borrelial infections in patients with spirochetemia. This highly sensitive, DNA sequencing-based test can even diagnose off-season spirochetemias with low bacterial density in the deep winter months in the Northeast of the United States when human exposure to tick bites was very limited.

2. Results and Discussion

Nested PCR amplification of a 600-nucleotide fragment of the 16S rDNA followed by direct DNA sequencing of the PCR amplicon has been used for construction of the phylogenetic tree of various Borrelia species [18,19]. One obstacle in transferring this methodology to diagnosing Lyme disease for patient care is the very low number of spirochetes in the blood of the patients even at the spirochetemic stage of the infection [6,20], and B. burgdorferi sensu stricto contains only one copy of 16S rDNA per cell [21]. PCR amplification of a 600-bp target DNA for direct DNA sequencing is technically challenging in a routine diagnostic laboratory because the sensitivity of 16S rDNA PCR amplification in diagnostic clinical microbiology is inversely related to the size of the PCR amplicon [22]. In addition, to construct the phylogenetic tree it is desirable to perform DNA sequencing on a segment of the gene with highly variable regions for its discriminatory power to distinguish different closely related species. The 600-nucleotide fragment of 16S rDNA selected for borrelial speciation [18,19] encompasses the highly discriminatory V-regions 1, 2, 3 and 4 of the 16S rDNA [23]. However, for molecular diagnostic nucleic acid amplification tests it is more beneficial to target less species-specific regions for amplification so that one fixed set of primers may detect as many clinically relevant pathogens of the same group as possible for timely diagnosis and patient management. For the latter reason, clinical laboratory diagnosticians are most interested in developing general PCR primers capable of amplifying a highly conserved segment of the 16S rDNA for all of the three tick-borne pathogenic borrelial species known to be prevalent in Europe and in the U.S.A., namely the species of B. burgdorferi sensu stricto, B. garinii and B. afzelii, often collectively referred to as B. burgdorferi sensu lato [24].

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