FAMILY I. RICKETTSIACEAE 



955 



gates in the lumen of the alimentary tract 

 and passes out with the feces. This is the 

 supposed means of transmission between 

 lice. The original lice were taken from 

 horses, but the latter are not presumed 

 hosts of the organism as the lice do not suck 

 the blood of their hosts. 



6. Wolbachia linognathi (Hindle, 1921) 

 Philip, 1956. (Rickettsm linognathi Hindle, 

 Parasitology, 13, 1921, 157; Philip, Canad. 

 Jour. Microbiol., 2, 1956, 267.) 



li.nog.na'thi. M.L. noun Linognafhus a 

 genus of sucking lice; M.L. gen. noun 

 linognathi of Linognathus. 



Resembles Wolbachia trichodectae in ap- 

 pearance. Stain bluish with Giemsa's stain. 



Cultivation: Not reported. 



Source: Observed in two of 57 goat lice 

 {Linognathus stenopsis), where it was found 

 extracellularly in the lumen of the gut. 

 Probably not pathogenic for the host, but 

 also not adapted to the point of occurring 

 in a high percentage of neighboring hosts. 



7. Wolbachia melophagi (Noller, 1917) 

 Philip, 1956. (Rickettsia melophagi Noller, 

 Arch. f. Schiffs- u. Tropen-Hyg., 21, 1917, 

 70; Philip, Canad. Jour. Microbiol., 2, 1956, 

 267.) 



me.lo'pha.gi. M.L. mas.n. Melophagus a 

 genus of sheep keds (sometimes incorrectly 

 called "ticks"); M.L. gen. noun melophagi of 

 Melophagus. 



Minute, rickettsia-like, extracellular, coc- 

 coid, ellipsoidal and, occasionaly, short 

 rods occurring characteristically in pairs of 

 fairly uniform size, 0.3 to 0.6 micron in 

 diameter. In eggs of the wingless-fly host, 

 the organisms are more rod-shaped with a 

 tendency to pleomorphism. In cultures, the 

 rods may measure up to 1.0 micron in length. 

 Stain purple with Giemsa's stain and reddish 

 with Macchiavello's stain. Gram-negative. 



Cultivation: This is the only one of the 

 rickettsia-like microorganisms that has 

 been confirmed as cultivable on non-living 

 media (glucose-blood-bouillon-agar). Also 

 grows in embryonated chicken eggs. 



Pathogenicity and source: Occurs as con- 

 tinuous or broken masses lining the intesti- 

 nal epithelium; occurs extracellularly in the 

 sheep ked ("sheep tick") (Melophagus 



ovinus). Intracellular growth has been 

 disputed and is not generally credited at 

 present. Injury to the host has not been re- 

 ported, and since this organism is almost 

 universally present, including the larvae of 

 the viviparous host, s3^mbiosis is an ad- 

 vanced stage approaching the condition in 

 Syinbiotes lectularius without the develop- 

 ment of mycetomes. Infection in ked-in- 

 fested sheep is disputed, and cultivation 

 from sheep's blood has been claimed. At 

 least such an infection is low-grade or in- 

 apparent as far as symptoms are concerned. 

 Laboratory animals, including vitamin-de- 

 ficient guinea pigs, have failed to become 

 infected by injection of cultures. 



8. Wolbachia dermacentrophila (Stein- 

 haus, 1942) Philip, 1956. (Rickettsia derma- 

 centrophila Steinhaus, U. S. Public Health 

 Rept., 57, 1942, 1376; Philip, Canad. Jour. 

 Microbiol., 2, 1956, 267.) 



der.ma.cen.tro'phi.la. M.L. noun Derma- 

 censor a genus of ticks; Gr. adj. philus 

 loving; M.L. adj. dermacentrophilus Derma- 

 centor -\o\mg. 



Minute, rickettsia-like organisms, meas- 

 uring 0.3 to 0.8 by 0.5 to 2.8 microns. May 

 occur joined in short chains of two or three 

 organisms or occasionally as filaments. On 

 the average, larger in size than Rickettsia 

 rickettsii. Stain reddish with Machiavello's 

 stain and bluish with Giemsa's stain. Not 

 acid-fast. Gram-negative. 



Cultivation : Failed to grow on 14 ordinary 

 cell-free, bacteriological media. Readily 

 cultivated in embryonated chicken eggs, 

 growing chiefly in yolk sacs and apparently 

 in the embryonic fluids. 



Pathogenicity and source: Found most 

 abundantly in the epithelial cells of the 

 intestinal diverticula of the Rocky Moun- 

 tain wood tick (Dermacentor andersoni) , but 

 may also occur throughout the various tis- 

 sues of the host. Extracellular occurrence is 

 also possible. Observed in every stage of the 

 tick host including the egg. Not lethal for 

 the tick host. Attempts at infecting various 

 laboratory animals susceptible to spotted 

 fever failed; such animals were not 

 immune to challenge with strains of tick- 

 borne, rickettsial pathogens. Spotted-fever- 



