An Outbreak of Leptospirosis among U. S. Army Troops in the Canal Zone

II. Isolation and Characterization of the Isolates

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  • Veterinary Laboratory Corozal, Balboa Heights, Canal Zone, and WHO/FAO Leptospirosis Reference Laboratory, Division of Veterinary Medicine, Walter Reed Army Institute of Research, Walter Reed Army Medical Center, Washington, D. C.


Serological studies were conducted on 29 leptospiral isolates obtained during an epidemiological investigation of an outbreak of human leptospirosis. The isolates were derived from urine of 2 of 6 patients, from 1 of 15 samples of surface water obtained at the locus of infection and from 15 of 106 trapped mammals as follows: 11 of 27 spiny rats (Proechimys semispinosus), 2 of 14 spiny pocket mice (Liomys adspersus), 1 of 3 opossums (Didelphis marsupialis) and 1 of 3 four-eyed opossums (Philander opossum). No leptospiras were isolated from 49 short-tailed bats (Carollia perspicillata), 6 small-eared bats (Micronycteris megalotis), and 4 long-tongued bats (Glossophaga soricina).

On the basis of cross-agglutination and agglutinin adsorption tests, seven different and hitherto unreported serologic types were classified and designated as follows: serotype bravo (hyos group) isolated from man, spiny rat and spiny pocket mouse; serotype weaveri (icterohaemorrhagiae group) isolated from man and spiny rat; serotypes canalzoni (cynopteri group) isolated from spiny rat, spiny pocket mouse and four-eyed opossum; kobbe (bataviae group) isolated from spiny rat; serotype pomona, subserotype tropica, isolated from spiny rat and spiny pocket mouse; maru (hebdomadis group) isolated from spiny rat and surface water; and panama (possible new group) isolated from opossum. Evidence of mixed infections was obtained in five animals. The bacteriological findings affirmed previous serological indications that Panama is an area of multiple leptospirosis.

Author Notes

Veterinary Laboratory Corozal, Box 459, Balboa Heights, Canal Zone. Present address: The Los Angeles Zoo, Los Angeles, California.

Division of Veterinary Medicine, Walter Reed Army Institute of Research, Washington, D. C. 20012.

Veterinary Laboratory Corozal.