Previously, nine fecal isolates from wild birds and a domestic swine were identified as helicobacters by phenotypic characterization and reaction with a helicobacter genus-specific DNA probe. These isolates fell into three biotypes by analysis of phenotypic traits. To further characterize these isolates, full 16s rRNA sequences were determined for strains representing each biotype, and sequence comparison indicated that the strains represented three novel, phylogenetically defined Helicobucter species. Three 16s rRNA-based DNA probes were designed and used to identify the remaining strains. Probe reactivity divided the strains into the same three groups identified phenotypically. Six of the isolates represented a new species of the genus Helicobucter for which we propose the name Helicobacter pumetensis sp. nov. The following phenotypic features distinguished H. pametensis from other Helicobucter and Cumpylobucter species: positive tests for oxidase, catalase, alkaline phosphatase, nitrate reduction, growth at 42"C, and growth in the presence of 1% glycine; negative tests for urease, gamma glutamyl transpeptidase, indoxyl acetate hydrolysis, and hippurate hydrolysis; and susceptibility to nalidixic acid and cephalothin. H. pametensis cells were motile and possessed one subterminal sheathed flagellum at each end. The two additional Helicobucter species were similar to H. pametensis except that they were urease positive, hydrolyzed indoxyl acetate, and were resistant to cephalothin. Because these two additional species are phenotypically similar and are represented by only two isolates for one species and one isolate for the other, they are not formally named but are referred to as Helicobucter sp. "Bird-B" and Helicobucter sp. "Bird-C." These three new Helicobacter species can easily be confused with Cumpylobucter coli, Cumpylobucter luri, and Cumpylobucter jejuni if only a limited number of phenotypic traits are used for identification. Since it is now known that birds can harbor Helicobacter as well as Cumpybbucter species, methods which clearly distinguish these genera should be used to identify bird campylobacter-like isolates or bacterial strains traceable to bird fecal contamination. The zoonotic potential of these new Helicobucter species should be examined.

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Ecologic studies of Venezuelan encephalitis (VE) virus at a marsh habitat near the epicenter of the 1969 outbreak in Guatemala revealed that the virus was enzootic there. VE virus was isolated yearly during 1968-1973 from sentinel hamsters exposed during the rainy seasons and from mosquitoes collected during July and August 1970. Hamsters yielded 41 strains of VE virus and virus was detected within 2 km of the edge of the marsh, in its interior, and at its western extreme 18 km from the central study site at La Avellana. One strain of virus came from a hamster that died in the dry season of January 1970. Culex mosquitoes yielded 20 strains of VE virus and Mansonia and Aedes one each. Culex (Melanoconion) and Aedes taeniorhynchus were most prevalent near the marsh. Hemagglutination-inhitibion (HI) and neutralization antibody tests of sera showed that wild terrestrial mammals (opossums and rodents), humans, and dogs, but not wild birds, were frequently infected. Seven of 16 susceptible residents of villages at the edge of the marsh developed antibodies without symptoms during an 18-month period between September 1971 and February 1973. Only 1 of 5 sentinel rabbits, and none of 30 sentinel chickens developed VE HI antibody during August-September 1971, a period when virus activity was readily detected by the use of sentinel hamsters. Five strains of group C arbovirus (one identified as Nepuyo) were recovered from sentinel hamsters during 1968 to 1970, and one strain of Nepuyo virus was isolated from the blood of a person with a febrile illness during 1972. Two strains of Patois group arboviruses were isolated from Culex mosquitoes during 1970.