Presence of Leptospiras spp. in populations of Caiman latirostris (Crocodylia, Alligatoridae)

BAUSO, J.; SIMONCINI, MELINA S.; CHIANI, Y.; VAÑASCO, N.V.; LARRIERA, A.; PIÑA, C.I.

Santa Fe

Congreso; 25th Working Meeting of the IUCN-SSC Crocodile Specialist Group; 2018

Leptospirosis is a disease caused by pathogenic spirochetes of the genus Leptospira, transmitted by wild and domestic animals. To know the variables related to the eventual acquisition of infection in animals have great importance for the design of sanitary policies. Our objective was to assess the prevalence of antibodies anti-leptospira and the presence of leptospiras spp. in Caiman latirostris in captivity and in the wild, in the north of Santa Fe province. Blood samples were taken from 45 individuals (20 wild animals and 25 in captivity). Before the extraction, we cleaned the neck of caimans, in order to prevent samples contamination. Anticoagulant blood with heparin was cultivated in two specials media, EMJH and Fletcher. From serum, the presence ofantibodies was determined by microscopic agglutination test (MAT) and polymerasechain reaction (PCR) to detect DNA of the bacteria. In addition we determined pH of the urine in captivity animals. pH was 8 (slightly alkaline pH). We excluded 9 of the 45 samples analyzed by MAT, because 5 had lipemic serum and 4 were contaminated. In 15 of 19 captivity samples and 11 of 17 wild samples, anti-leptospira antibodies were detected by MAT. In 69.2% (18 of 26) of these samples the presumably infecting serogroup was Pyrogenes, presenting coagglutinations with Icterohaemorrhagiae (23.1%) and with Icterohaemorrhagiae and Grippothyphosa (3.8%). Other serogroups detected were: Canicola, Autumnalis, Copenhageni, Grippothyphosa, Tarassovi, Wolffi and Javanica. On the samples analyzed by PCR, one of a captivity animal was positive; from this sample we could not isolate leptospires because of agar contamination. Blood agar media were negative, but 17.8% (8 of 45) of them were contaminated. This work allows to determine the presence of Leptospira spp. in one caiman, and the high prevalence of antibodies, both in captivity and nature. In this way, it concludes thatcaiman are in frequent contact with the bacteria at some point in their lives, and that they could present an acute infection without any obvious symptoms. According to the pH obtained, to the seroprevalence found and that the caimans spend time taking in the margins of the bodies of water, where the water is very shallow and the temperature is high, there would be adequate conditions for the transmission of this disease in the studied area and in places where this species frequently lives.