EXTRACELLULAR AND INTRACELLULAR RICKETTSIA-LIKE MICROORGANISMS IN GONADS OF MOSQUITOS

The mosquitoes Culex tigripes, C. decens and C. quinquefasciatus have been investigated by electron microscopy. An intracytoplasmic ricketts ia-like microorganism is present in ovaries and testes of the three sp ecies. An extracellular form of a rickettsia-like microorganism is des cribed in the testis of C. tigripes in which it sometimes appears in g reat number. The extra- and intracellular forms present ultrastructura l differences. The possibility they represent two different morphotype s of the same microorganism or simply two different types is discussed . They both disappear after treatment with tetracycline. This is belie ved to be the first electron microscope description of extracellular r ickettsia-like cells in mosquitoes.