Individuals from 13 wild mammalian species collected in southwestern Tennessee were serologically positive for anti-Naegleria spp. antibodies (ANA). This is the first report of ANA in wild mammals. Interspecific differences in the occurrence of ANA and titers indicate that wild mammals have differing degrees of contact with Naegleria spp. based on ecological or behavioral adaptations, and possibly the innate ability of a species to produce ANA. Intraspecifically, it appears that if a mammal is exposed to Naegleria spp. in the environment, titers of ANA will not significantly differ, regardless of age or sex. Adults of many species had significantly higher occurrences of ANA. Populations of juvenile wild mammals are probably at higher risk than adults to naeglerial infection in the environment, not because of lower titers, but because their chance of having ANA is less than adults. Differences in the occurrence of ANA in wild mammals may also reflect how humans are exposed to Naegleria spp. in the environment.

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Aquarium-observations on a new paedophagous haplochromine species (Pisces, Cichlidae) showed that engulfing the snout of a brooding female to extract the brood, is a possible technique of gathering food, as was suggested by GREENWOOD (1959, 1974). Considering morphological information from various authors (GREENWOOD, 1959, 1974; BAREL et al., 1976, 1977) and notwithstanding some doubt expressed by FRYER & ILES (1972) and FRYER (1977), this snout-engulfing may be a widespread technique among the "larger mouthed" paedophages (i. e. in Lake Victoria: 6 out of 8 spp. described plus at least 8 new spp.). Snout-engulfing is the climax of a performance which resembles a fight, during which the paedophage also can force a brooding female to disgorge its brood by chasing and repeated attacks. The origin of snout-engulfing may be thought to lie in a modification of the fighting behaviour of a piscivorous ancestor, hunting on already jettisoned young still guarded by the female.

The stomachs and intestinal tracts of 253 raccoons, Procyon lotor, were examined for helminth parasites. Sixteen species of helminths were found including eight trematodes, two cestodes, five nematodes, and one acanthocephalan. Fourteen of these helminths are new geographic records for the state of Tennessee. Multivariate statistical techniques were used to analyze two-state and multistate character sets. Matrices of correlation among characters were computed and the first three principal components were extracted, accounting for 79.7% and 66.5% of the variation in the respective character sets. Three-dimensional projections of Tennessee's eight geographic localities onto two-state and multistate principal components demonstrated that raccoons in western localities were parasitized most heavily by Atriotaenia procyonis. Mesocestoides variabilis, Gnathostoma procyonis, and Pharyngostomoides procyonis. Parallelorchis diglossus, Euparyphium beaveri. Eurytrema procyonis, Euryhelmis squamala, Molineus barbatus, and Macracanthorhynchus ingens were most common to P. lotor from eastern areas.

B and rhodotorulic acid, iron-chelating agents of microbial origin, exerted a pronounced inhibitory effect on pathogenic Naegleria fowleri at microgram levels. This inhibition was diminished by adding iron to the chelators before incubation with Naegleria isolates. These and related microbial iron chelators occur naturally in the environment. This could be of considerable ecological significance and provides a novel hypothesis to account for the proliferation of pathogenic Naegleria spp. in certain aquatic habitats.

An avidin-biotin horseradish peroxidase method was used to detect antibodies to Naegleria fowleri and N. lovaniensis in human serum samples. Antibodies were detected in 101 specimens from 115 hospital patients ranging in age from 15 to 98 years. Class-specific anti-immunoglobulins identified antibodies as IgG and IgM. IgG antibody titers to both species ranged from 1:20 to 1:640. Seven of 15 serum samples collected from newborn infants also demonstrated IgG antibodies to these organisms with a titer range of 1:20 to 1:80. The immunoperoxidase test and Western blot analysis of selected serum samples demonstrated a close similarity in serological results between N. fowleri and N. lovaniensis.

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