Neorickettsia sennetsu as a Neglected Cause of Fever in South-East Asia.

Neorickettsia sennetsu infection is rarely recognized, with less than 100 globally reported patients over the last 50 years. The disease is thought to be contracted by eating raw fish, a staple of many South-East Asian cuisines. In 2009, the first patient with sennetsu was identified in the Lao PDR (Laos), raising the question as to how common this organism and related species are in patients presenting with fever.

Co-circulation of multiple species of Rickettsiales bacteria in one single species of hard ticks in Shenyang, China.

Bacteria in the order Rickettsiales include some of the most important zoonotic (re)emerging pathogens for animals and humans. In 2012, a total of 1267 adult Haemaphysalis longicornis ticks were collected from domestic animals (cattle and sheep) in Shenyang of Liaoning Province, China. These ticks were grouped into 181 pools (each pool with 6-7 ticks).

Extensive diversity of Rickettsiales bacteria in two species of ticks from China and the evolution of the Rickettsiales.

Background: Bacteria of the order Rickettsiales (Alphaproteobacteria) are obligate intracellular parasites that infect species from virtually every major eukaryotic lineage. Several rickettsial genera harbor species that are significant emerging and re-emerging pathogens of humans. As species of Rickettsiales are associated with an extremely diverse host range, a better understanding of the historical associations between these bacteria and their hosts will provide important information on their evolutionary trajectories and, particularly, their potential emergence as pathogens.

A morphological and molecular study of Anaplasma phagocytophilum transmission events at the time of Ixodes ricinus tick bite.

Background: Anaplasma phagocytophilum is the causative agent of human granulocytic anaplasmosis (HGA) in humans and tick-borne fever (TBF) in ruminants. The bacterium invades and replicates in phagocytes, especially in polymorphonuclear granulocytes.

Methods: In the present study, skin biopsies and ticks (Ixodes ricinus) were collected from tick feeding lesions on 38 grazing lambs between two and three weeks after access to pastures.