MeSH definition : A family of small, gram-negative organisms, often parasitic in humans and other animals,
causing diseases that may be transmitted by invertebrate vectors.; A family of gram-negative bacteria belonging to the order Rickettsiales.;
MeSH annotation : a family: do not confuse with RICKETTSIEAE, a tribe; infection RICKETTSIACEAE INFECTIONS;
A family of small, gram-negative organisms, often parasitic in humans and other animals,
causing diseases that may be transmitted by invertebrate vectors. A family of gram-negative bacteria belonging to the order Rickettsiales.