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Algiers, Algeria

Socolovschi C.,French National Center for Scientific Research | Gaudart J.,Aix - Marseille University | Bitam I.,Institute Pasteur dAlgerie | Huynh T.P.,French National Center for Scientific Research | And 2 more authors.
PLoS Neglected Tropical Diseases | Year: 2012

Background: Rickettsia conorii conorii is the etiological agent of Mediterranean spotted fever, which is transmitted by the brown dog tick, Rhipicephalus sanguineus. The relationship between the Rickettsia and its tick vector are still poorly understood one century after the first description of this disease. Methodology/Principal Findings: An entomological survey was organized in Algeria to collect ticks from the houses of patients with spotted fever signs. Colonies of R. conorii conorii-infected and non-infected ticks were established under laboratory conditions. Gimenez staining and electron microscopy on the ovaries of infected ticks indicated heavy rickettsial infection. The transovarial transmission of R. conorii conorii in naturally infected Rh. sanguineus ticks was 100% at eleven generations, and the filial infection rate was up to 99% according to molecular analyses. No differences in life cycle duration were observed between infected and non-infected ticks held at 25°C, but the average weight of engorged females and eggs was significantly lower in infected ticks than in non-infected ticks. The eggs, larvae and unfed nymphs of infected and non-infected ticks could not tolerate low (4°C) or high (37°C) temperatures or long starvation periods. R. conorii conorii-infected engorged nymphs that were exposed to a low or high temperature for one month experienced higher mortality when they were transferred to 25°C than non-infected ticks after similar exposure. High mortality was observed in infected adults that were maintained for one month at a low or high temperature after tick-feeding on rabbits. Conclusion/Significance: These preliminary results suggest that infected quiescent ticks may not survive the winter and may help explain the low prevalence of infected Rh. sanguineus in nature. Further investigations on the influence of extrinsic factors on diapaused R. conorii-infected and non-infected ticks are required. © 2012 Socolovschi et al. Source

Kernif T.,Aix - Marseille University | Kernif T.,Institute Pasteur dAlgerie | Leulmi H.,Aix - Marseille University | Socolovschi C.,Aix - Marseille University | And 7 more authors.
Molecular Ecology | Year: 2014

Bartonella quintana is transmitted by the infected faeces of body lice. Recently, this bacterium was detected in cat fleas (Ctenocephalides felis) and in two humans with chronic adenopathy whose only risk factor was contact with cat fleas. In this study, a total of 960 C. felis were divided into 12 groups (2 control groups and 10 infected groups) each containing 80 fleas. The fleas were fed B. quintana-inoculated human blood at different dilutions (≈3.6 × 104 - 8.4 × 109 bacteria) for 4 days via an artificial membrane. Subsequently, all flea groups were fed uninfected blood until day 13 postinfection (dpi). On day 3 pi, B. quintana was detected with two specific genes by quantitative PCR in 60-100% of randomly chosen fleas per dilution: 52% (26/50) in the infected fleas in Trial 1 and 90% (45/50) of the fleas in Trial 2. B. quintana was also identified by molecular and culture assays in flea faeces. The average number of B. quintana as determined by qPCR decreased until the 11th dpi and was absent in both trials at the 13th dpi. Bacteria were localized only in the flea gastrointestinal gut by specific immunohistochemistry. Our results indicate that cat fleas can acquire B. quintana by feeding and release viable organisms into their faeces. Therefore, fleas may play a role as vectors of trench fever or other clinical manifestations that are caused by B. quintana. However, the biological role of C. felis in the transmission of B. quintana under natural conditions is yet to be defined. © 2014 John Wiley & Sons Ltd. Source

Drali R.,Aix - Marseille University | Drali R.,Institute Pasteur dAlgerie | Boutellis A.,Aix - Marseille University | Raoult D.,Aix - Marseille University | And 2 more authors.
PLoS ONE | Year: 2013

Background: Body louse or head louse? Once removed from their environment, body and head lice are indistinguishable. Neither the morphological criteria used since the mid-18th century nor the various genetic studies conducted since the advent of molecular biology tools have allowed body lice and head lice to be differentiated. In this work, using a portion of the Phum_PHUM540560 gene from the body louse, we aimed to develop a multiplex real-time polymerase chain reaction (PCR) assay to differentiate between body and head lice in a single reaction. Materials and Methods: A total of 142 human lice were collected from mono-infested hosts from 13 countries on five continents. We first identified the louse clade using a cytochrome b (CYTB) PCR sequence alignment. We then aligned a fragment of the Phum_PHUM540560 gene amplified from head and body lice to design-specific TaqMan© FAM- and VIC-labeled probes. Results: All the analyzed lice were Clade A lice. A total of 22 polymorphisms between the body and head lice were characterized. The multiplex real-time PCR analysis enabled the body and head lice to be distinguished in two hours. This method is simple, with 100% specificity and sensitivity. Conclusions: We confirmed that the Phum_PHUM540560 gene is a useful genetic marker for the study of lice. © 2013 Drali et al. Source

Raoult D.,Aix - Marseille University | Mouffok N.,Oran University of Science and Technology - Mohamed Boudiaf | Bitam I.,Institute Pasteur dAlgerie | Piarroux R.,Laboratoire Of Parasitologie Et Mycologie | And 2 more authors.
Journal of Infection | Year: 2013

Plague has caused ravaging outbreaks, including the Justinian plague and the "black death" in the Middle Ages. The causative agents of these outbreaks have been confirmed using modern molecular tests. The vector of plague during pandemics remains the subject of controversy. Nowadays, plague must be suspected in all areas where plague is endemic in rodents when patients present with adenitis or with pneumonia with a bloody expectorate. Diagnosis is more difficult in the situation of the reemergence of plague, as in Algeria for example, told by the first physician involved in that outbreak (NM). When in doubt, it is preferable to prescribe treatment with doxycycline while waiting for the test results because of the risk of fatality in individuals with plague. The typical bubo is a type of adenitis that is painful, red and nonfluctuating. The diagnosis is simple when microbiological analysis is conducted. Plague is a likely diagnosis when one sees gram-negative bacilli in lymph node aspirate or biopsy samples. Yersinia pestis grows very easily in blood cultures and is easy to identify by biochemical tests and MALDI-TOF mass spectrometry. Pneumonic plague and septicemic plague without adenitis are difficult to diagnose, and these diagnoses are often made by chance or retrospectively when cases are not part of an epidemic or related to another specific epidemiologic context. The treatment of plague must be based on gentamicin or doxycycline. Treatment with one of these antibiotics must be started as soon as plague is suspected. Analysis of past plague epidemics by using modern laboratory tools illustrated the value of epidemic buboes for the clinical diagnosis of plague; and brought new concepts regarding its transmission by human ectoparasites. © 2012 The British Infection Association. Source

Parola P.,Aix - Marseille University | Paddock C.D.,Centers for Disease Control and Prevention | Socolovschi C.,Aix - Marseille University | Labruna M.B.,University of Sao Paulo | And 8 more authors.
Clinical Microbiology Reviews | Year: 2013

Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases. © 2013, American Society for Microbiology. All Rights Reserved. Source

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