Electron micrograph shows foot-and- 

 mouth disease virus particles 

 (about one-millionth inch in diam- 

 eter). One polystyrene reference 

 particle is at left center. 



mm mmimm 



^ Pioneered in the use of tissue-culture monolayers in the 

 study of animal viruses. 



^ Adapted vesicular stomatitis virus to growth in tissue 

 culture. ^ 



^ Isolated vesicular ston^»atitis virus from an infected hu- 

 man being. 



► Developed a tissue culture plaque assay for foot-and- 

 mouth disease virus (FMDV). 



► Developed a line of lamb testis cells, which supports the 

 growth of the seven types of FMDV. 



^ Viewed foot-and-mouth disease vims in the electron mi- 

 croscope, and described it as a paiticle approximately 

 23 millimicrons (about one-millionth inch) in diameter, 

 made up of a protein coat which protects a core of 

 ribonucleic acid (RNA). 



^ Confirmed that the protein coat may be removed from 

 the RNA core of FMDV, and that the RNA core is the 

 infectious portion. 



► Established that ribonuclease (RNase) — an enzvme 

 widespread in animal tissues — rapidly digests RNA, but 

 does not affect intact FMDV. Developed methods to 

 inactivate RNase. 



► Showed that FMDV is heat resistant, but mav be inacti- 

 vated by heating at 8.V C. for 6 hours. 



► Demonstrated that RNA, capable of producing infection, 

 may be obtained from, boiled FMDV. 



^ Found that FMDV multiplies without clinical signs of 

 infection in several species of animals not known to be 

 naturally susceptible. 



Confirmed that the separated RNA core can reproduce 

 whole FMDV when ino(n}lated in cattle. 



Established that FMDV survives in lymph nodes and 

 blood of beef carcasses for as long as 60 days, in bone 

 marrow for more than 6 months, and in l\ni])h nodes of 

 wet, salt-cured meat for as long as 50 days. 



Determined that FMDV persists in cattle kidneys after 

 clinical signs of disease disappear. 



Demonstrated that glycolylic metabolism (nonoxidative 

 breakdown of sugar) is more essential to FMD viral 

 reproduction than are oxidative reactions. 



Found that FMDV is inacli^ated by organic acids, and 

 by ethylene oxide gas. when sufllcient humidity is pres- 

 ent, and that beta-propiola('i()n(\ acetylethyleneiniine, 

 and ethylene oxide may be us(;d as inactivants when 

 retention of antigenicity is desired. 



Determined that FVIDV may be j)resent in semen of 

 infected bulls and may be transmitted to cows by arli- 

 ficial insemination. 



Developed a rapid laboratory diagnostic test for African 

 swine fever, in cooperation witli thf^ Fast African Vet- 

 erinary Research Organization. 



Attenuated a strain of rinderpest virus, which shows 

 promise as a live-viriis vacM-ine for catt:le. 



Found that rinderpest viiris suspensions contain at least 

 two different ])articles. 



Developed a rapid serological test for diagnosis of 

 rinderpest. 



Improved procedures for differentiating the types of 

 vesicular exanthema virus. 



