Annals of the New York Academy of Sciences
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Ann. N. Y. Acad. Sci. · May 2009
Deciphering the relationships between Rickettsia conorii conorii and Rhipicephalus sanguineus in the ecology and epidemiology of Mediterranean spotted fever.
Mediterranean spotted fever is the most important tick-borne disease occurring in Southern Europe and North Africa. The first case of this life-threatening zoonosis was reported in 1910. In the 1930s, the role of the brown dog tick, Rhipicephalus sanguineus, and the causative agent, Rickettsia conorii were described. ⋯ The long-recognized phenomenon known as reactivation has been suggested as a cause of negative effects--that is, the change in temperature and physiology of the tick host induces the agent to emerge from dormancy and attain infectivity with bad effects on ticks. However, naturally infected colonies of ticks have been maintained in laboratory conditions over several generations. We discuss here several aspects that have been recently studied to better understand Rh. sanguineus-R. conorii relationships, including comparison between the fitness of infected and non-infected ticks in laboratory conditions and the role of external factors such as temperature and starvation.
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Familial episodic ataxias are inherited channelopathies that manifest as episodes of vertigo and ataxia triggered by emotional stress and physical exertion. Mutations in two neuronal ion-channel genes KCNA1 and CACNA1A abundantly expressed in the cerebellum account for the majority of the identified cases of episodic ataxia. Overlapping features between episodic ataxia and the more common recurrent vertigo and ataxia syndromes, particularly those associated with migraine, suggest shared underlying mechanisms. ⋯ Given the familial aggregation of migraine and migrainous vertigo, our objective was to identify predisposing genetic factors. Preliminary findings demonstrate that migrainous vertigo is genetically heterogeneous and complex. Efforts are ongoing to perform genomewide association studies to identify risk alleles for migrainous vertigo, which may also be relevant to migraine in general.
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The rickettsial diseases of Australia are described in their chronological order of discovery. The include epidemic typhus (R. prowazekii); murine typhus (R. typhi) found Australia-wide; scrub typhus (O. tsutsugamushi) only in tropical, northen Australia; Q. fever (C. burnetti) found Australia-wide; Queensland tick typhus (R. australis) along the east coast of Australia; Flinders Island spotted fever (R. honei) in southeast Australia; Variant Flinders Island spotted fever (R. honei, strain "marmionii") in eastern Australia; Rickettsia felis, Western Australia; eight new RFG rickettsiae from ticks (of unknown pathogenicity); and two nonhuman pathogens in A. platys (dogs) and A. marginale (cattle).
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Ann. N. Y. Acad. Sci. · May 2009
ReviewQ Fever during pregnancy: a cause of poor fetal and maternal outcome.
Q fever is a worldwide zoonosis caused by Coxiella burnetii. Q fever may be present as an acute or a chronic infection and can be reactivated during subsequent pregnancies. Although its exact prevalence remains unknown, it is likely that the number of cases of Q fever in pregnant women is underestimated. ⋯ Such treatment should be used to treat pregnant women with Q fever. Women with previous history of Q fever should have a regular serological follow up. Obstetricians' knowledge about Q fever must be improved.