The Laroche Lab studies the epidemiology, transmission and
pathogenesis of bacteria infecting the endothelium. The current main
projects are listed below:
- Investigate the ecology of Rickettsia rickettsii in the U.S. and Latin America. Rocky
Mountain spotted fever is a life-threatening, yet neglected, bacterial
vector-borne disease transmitted by ticks in the
Americas. The fatality rates are significantly
higher in Latin America. We use tick/animal transmission models,
virulence studies etc. to explore the bases of this observation and
explain whether these disparities in mortality
rates are due to the tick vectors, the
rickettsial clades or other factors.
- Acute febrile illnesses in displaced populations.
Refugee camps are a favorable environment for the emergence,
maintenance and spread of human pathogens. We determine the burden of
vector-borne bacterial diseases among
other etiologies of acute undifferentiated
fevers in refugee populations from East-Africa and migrant populations
from South America. Isolates from febrile patients, arthropods and
animals are fully characterized and transmission
models are performed in order to confirm vector
transmission. Rickettsia and Bartonella spp. isolates are further used for pathogenesis studies.
- Pathogenesis of Bartonella species. Bartonella
species are vector-borne bacteria commonly associated with domestic
animals and small wild rodents and transmitted by fleas and lice. They
are highly sensitive
to antibiotics and rarely cause severe
infections in immunocompetent patients. In immunocompromised patients,
they can cause a wide range of clinical manifestations that include
endocarditis, bacillary angiomatosis, bacillary peliosis,
encephalopathy, neuroretinitis etc. We study the
pathogenesis of Bartonella species in the endothelium using in vitro and in vivo models of severe bartonellosis.