Thimiri, a new Simbu group virus, has been isolated in Vellore, India and 
twice in southward migrating warblers in Egypt. The presence of viremic 
southward migrants suggests that there are enzootic foci in Eurasia (other 
than Vellore), as yet unrecognized. The significance of this virus as a 
cause of human disease in Europe or Asia is not known. A related new-world 
virus, Oropouche, has caused severe, wide-spread human febrile illness in 
Brazil. 
The most frequently encountered viruses in the blood of palearctic 
migrants belong to the Tete group. At least two sero-types, Bahig (Watson 
al , 1969) and Matruh are recognized. They are characteristically found 
in fall migrants, primarily in warblers, thrushes, and finches. In one 
species^ Sylvia communis ^in 1968, 9.3% of 54 birds tested were infected. This 
is a regular annual virus introduction into Africa as evidenced by the NAMRU-3 
study in 1961 to 1963 and the present study 1966 to 1968. 
The current working hypothesis is that the Bahig and Matruh viruses are 
enzootic somewhere in Europe. This hypothesis is strenthened by the isolation 
of 2 viruses of the Bahig complex from migrating Fringilla in Gorizia Province, 
Italy in November 1968 (Balducci, personal communication). The actual European 
enzootic focus is yet to be found, however. One might also hypothesize that 
infected birds would be predominately juveniles since adults might be immune. 
In actual experience during 1968 when individual (rather than pooled) specimens 
were examined, there was no significant difference between isolation rates 
from juveniles and adults. There was also no sex difference. 
The 1968 isolates, typed by neutralization test, represented both Bahig 
and Matruh types (Table 16). On any given day, all of the Isolates were of 
one type. This might be explained in at least 3 ways, 1) that there was cross¬ 
contamination in the laboratory during bleeding or isolation attempts-unlikely 
80 
