P. Brouqui

Transmission of Rickettsia massiliae in the tick, Rhipicephalus turanicus

Abstract.  Rickettsia massiliae, strain Bar29, was detected in engorged female ticks of the Rhiphicephalus sanguineus group collected in Corsica, a French Mediterranean island. Ticks were identified by molecular analysis as Rhipicephalus turanicus (Pomerantsev) (Acari: Ixodidae). Twenty larvae of the second generation obtained from a R. massiliae‐infected, engorged female were tested by polymerase chain reaction (PCR) and all were positive for R. massiliae. Larvae of the same cohort were fed on rabbits and specimens of subsequent stages of the second and third generation of ticks were tested by PCR. Both transovarial and transstadial transmission were demonstrated; the transovarial transmission rate was estimated at 100%. A high filial infection rate was demonstrated; 132 out of 134 larvae obtained from five infected females of the fourth generation were infected. When saliva samples from half‐engorged Rh. turanicus of the second generation were tested by PCR, four out of five were positive. Rickettsia massiliae was detected in faeces of infected ticks by PCR and immunofluorescence assay, although no rickettsiae could be maintained in culture. Co‐feeding/transsexual transmission of R. massiliae Bar29 was demonstrated by feeding male Rh. turanicus on a rabbit with Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) females (the latter were the only uninfected ticks available). Infection was subsequently detected in nine out of the thirteen females (69.2%). These results suggest that Rh. turanicus ticks are potential vectors and reservoirs for R. massiliae Bar29.

Human louse-transmitted infectious diseases

Several of the infectious diseases associated with human lice are life-threatening, including epidemic typhus, relapsing fever, and trench fever, which are caused by Rickettsia prowazekii, Borrelia recurrentis, and Bartonella quintana, respectively. Although these diseases have been known for several centuries, they remain a major public health concern in populations living in poor-hygiene conditions because of war, social disruption, severe poverty, or gaps in public health management. Poor-hygiene conditions favour a higher prevalence of body lice, which are the main vectors for these diseases. Trench fever has been reported in both developing and developed countries in populations living in poor conditions, such as homeless individuals. In contrast, outbreaks of epidemic typhus and epidemic relapsing fever have occurred in jails and refugee camps in developing countries. However, reports of a significantly high seroprevalence for epidemic typhus and epidemic relapsing fever in the homeless populations of developed countries suggest that these populations remain at high risk for outbreaks of these diseases. Additionally, experimental laboratory studies have demonstrated that the body louse can transmit other emerging or re-emerging pathogens, such as Acinetobacter baumannii and Yersinia pestis. Therefore, a strict survey of louse-borne diseases and the implementation of efficient delousing strategies in these populations should be public health priorities.

Experimental infection of Rhipicephalus sanguineus with Rickettsia conorii conorii

Little is known about the relationships between Rickettsia conorii conorii, the agent of Mediterranean spotted fever (MSF), and its main vector, the brown dog tick Rhipicephalus sanguineus [1]. Matsumoto et al. recently reported a high mortality of Rh. sanguineus group ticks infected with R. conorii conorii by several methods including the use of a bacteraemic rabbit [2]. It had been speculated that reasons for this reduction in fitness might include the geographic origin of the ticks, which came from Thailand where R. conorii conorii has not been reported, or was associated with the pathogen load acquired during laboratory experiments. Here we present complementary experiments to test these hypotheses.

Facing highly infectious diseases: new trends and current concepts

Abstract A highly infectious disease (HID) that is transmissible from person to person causes life-threatening illness and presents a serious hazard in the healthcare setting and in the community that requires specific control measures. Due to environmental factors, changes in lifestyle and many other unknown factors, the emergence of such HIDs is becoming more and more likely. As has already been demonstrated during the SARS outbreak, healthcare facilities are likely to be the origin of future HID outbreaks. Preparedness planning will be essential in helping facilities manage future outbreaks of emerging or resurgent infectious diseases. Guidelines have been developed by national and international institutions. To avoid contamination of healthcare workers, the care of HID patients should follow the same infection control rules that are applied to laboratory workers exposed to similar agents. Here, the current knowledge concerning the clinical care of patients with HIDs is reviewed, and specific aspects of the management of such diseases are introduced.

Detection of Anaplasmataceae in ticks collected in Morocco

Bacteria within the Anaplasmataceae include Gram-negative intracellular bacteria that have been known for a long time as the agents of veterinary diseases. However, in the recent years, five members of Anaplasmataceae have been reported to infect humans, including Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis, Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis, and E. ewingii, E. canis and Neorickettsia sennetsu [1]. The abundance of ticks in North Africa represents potential risks for animal and human public health. However, agents within the Anaplasmataceae family have been poorly investigated in North Africa, including in Morocco. In this work, we analysed ticks collected in this country for evidence of infection by Anaplasmataceae.