Further determination of DNA relatedness between serogroups and serovars in the family Leptospiraceae with a proposal for Leptospira alexanderi sp. nov. and four new Leptospira genomospecies.

DNA relatedness was determined among 303 strains of Leptospira and Leptonema. Included in the analysis were reference strains from 228 well-characterized and recognized serovars. The study included 268 serovars from 29 named and one or more unnamed serogroups. The strains clustered into 17 DNA hybridization groups, representing 12 previously described species (292 strains) and five new genomospecies (11 strains). The largest groups included Leptospira interrogans (91 strains from 82 serovars), Leptospira santarosai (65 strains from 59 serovars), Leptospira borgpetersenii (49 strains from 43 serovars), Leptospira kirschneri (29 strains from 26 serovars) and Leptospira noguchii (20 strains from 20 serovars). The new genomospecies include Leptospira genomospecies 1 (two strains, serovars pinagchang and sichuan), Leptospira genomospecies 2 (six strains, serovars lushui, manhao 3, manzhuang, nanding, mengla and yunnan), Leptospira genomospecies 3 (one strain, serovar holland), Leptospira genomospecies 4 (one strain, serovar hualin) and Leptospira genomospecies 5 (one strain, serovar saopaulo). With the exception of Ballum, all serogroups with greater than one serovar studied were genetically heterogeneous. Phenotypic tests, including optimal growth temperature, lipase activity and growth inhibition by copper sulfate or 2,6-diaminopurine, were of little use in differentiating DNA relatedness groups. The name Leptospira alexanderi sp. nov. is proposed for Leptospira genomospecies 2 (type strain L 60T = ATCC 700520T, serovar manhao 3).

Immunofluorescent staining of Treponema in tissues fixed with formalin.

Immunofluorescent examination of formalin-fixed tissue for Treponema pallidum has generally been unsatisfactory because of nonspecific background fluorescence and poor contrast. We examined the process of treating deparaffinized formalin-fixed tissue sections with 1% ammonium hydroxide (NH4OH) to improve fluorescent staining. Treponema pallidum- and Treponema pertenue-infected rabbit testes or human tissue biopsy specimens fixed in 10% buffered formalin and embedded in paraffin were examined. Sections were cut one week to five years after embedment. Tissues were then stained with fluorescein- or rhodamine-labeled human anti- T pallidum globulin for 30 minutes at 37 degrees C. Treponemes were consistently stained and background staining was generally reduced after NH4OH treatment in both fresh and stored tissue. Cutting sections at a thickness of approximately 2 micron was critical to achieve optimal fluorescence.

Bim, a new serovar of Leptospira interrogans isolated from a dog in Barbados.

A new serovar of Leptospira interrogans was isolated from a dog in Barbados. The proposed name of the new serovar is bim, and the designated type strain is 1051. The serogroup of the new serovar is the Autumnalis serogroup. The new serovar was subsequently isolated from six patients with leptospirosis in Barbados.

Six new leptospiral serovars isolated from wild animals in Peru.

Six new serovars of Leptospira interrogans were isolated from opossums (Didelphis marsupialis and Philander opossum) trapped in the Peruvian jungle. The proposed names, type strain designation, and serogroup of the serovars, respectively, were: huallaga, strain M-7, Djasiman serogroup; luis, strain M-6, Tarassovi serogroup; machiguenga, strain MMD-3, Icterohaemorrhagiae serogroup; rioja, strain MR-12, Bataviae serogroup; rupa rupa, strain M-3, Sejroe serogroup; and tingomaria, strain M-13, Cynopteri serogroup.

Isolations of Leptospira interrogans serovars hardjo, balcanica, and pomona from cattle at slaughter.

Kidneys were cultured for leptospires and blood was collected for leptospiral serologic examination from 306 cattle slaughtered in Florida during June, July, and August 1980. Leptospires were found in 82(36%) of 226 otherwise bacterial-free cultures. Forty-five isolates were identified as Leptospira interrogans serovar hardjo, 3 as serovar balcanica, and 3 as serovar pomona. Leptospiral antibodies were found in 218 (71%) of the cattle. Serum titers to hardjo were found in 162 cattle (53%) and to pomona in 28 (9%). Low titers to tarassovi were found in 14 cattle (4.5%).

Canine leptospirosis in Puerto Rico.

Among 116 stray dogs in Puerto Rico surveyed for leptospiral agglutinins, 73 (62.9%) has significant titers to one or more leptospiral serotypes. The most common serogroup identified serologically was icterohaemorrhagiae accounting for 53 (72.6%) of the infections. Although the infection rates were comparable for male and female dogs the older were found to be more frequently infected. The significance of the canine in the epidemiology of leptospirosis in Puerto Rico is probably of paramount importance due to the extensive direct and indirect contact dogs have with rats and the human population.

Leptospira interrogans serovars hardjo and pomona: causes of infections in dairy cows and humans in Florida.

Leptospirosis was diagnosed in 11 milkers on 3 dairy farms in a Florida county. Serologic test results identified Leptospira interrogans serovar hardjo as the infecting organism in milkers and cows on one farm, and hardjo was isolated from two cows. On the second farm, serovars hardjo and pomona were implicated serologically in the cows and milkers, and pomona was isolated from two milkers. On the third farm, hardjo infection was identified by serologic tests in one milker, and hardjo was isolated from another.This was the first isolation of hardjo from a human being reported in the United States. Leptospiral infection is an occupational hazard for dairy milkers in some areas of the United States. Thus, the authors recommend that preventive measures should be taken. These measures should include boots and other protective clothing and protection from urine spray for the eyes and nose.

Study of coinciding foci of malaria and leptospirosis in the Peruvian Amazon area.

A hyperendemic malaria focus, found in 1973 in a secluded valley in South-eastern Peru, was restudied in 1975. Tests for antibodies to Plasmodium and Leptospira were performed on blood serum and blood slides collected at three locations on the Rio Ene and confluent streams and at two locations in the neighbouring highlands. The hyperendemic focus of P. vivax-P. malariae found at Mission Cutivirini in 1973 was confirmed in this study. Another hyperendemic focus of predominantly P. vivax was found at the village of Saoreni. Lesser amounts of malaria were found at other locations. Serology indicated past or present contact with Leptospira of from 50 to 75% of individuals at all locations. The two hyperendemic malaria foci therefore were embedded in a much larger hyperendemic focus of leptospirosis. The value of the indirect immunofluorescence test for malarial antibodies as a sero-epidemiological tool was emphasized by this study.