16th ICID Abstracts / International Journal of Infectious Diseases2014, 21S: 1–460Background: Leptospirosis is a neglected zoonotic disease of worldwide public health importance which affects both humans, domestic and wildlife. Our previous study in Katavi ecosystem showed that prevalence of leptospirosis in livestock was 28%. This predisposes the agro-pastoralist communities at high risk of the diseases. Microscopic agglutination test (MAT) is the gold standard technique for diagnosis of Leptospirosis. This cross sectional study intended to provide serological data for the circulating Leptospira species in Western part of Tanzania. Methods & Materials: 265 blood samples from healthy partici- pants living in Katavi ecosystem were collected in plain vacutainer tubes, centrifuged for sera collection and stored in liquid nitro- gen. Urine samples were also collected and cultured in Fletcher Leptospira media for isolation of live organism. To be certain of other causes of febrile illness in the region; Screening tests for malaria and brucellosis (mRDT and Rose Bengal) were done respec- tively. All samples were processed at Mpanda District Hospital and transported to Sokoine University of Agriculture (SUA) for further analysis. (MAT) was done using six known Leptospira interrogans serovars: Pomona, Icterohaemorrhagiae, Ballum, Tarassovi, Grippotyphosa and Hardjo. Starting with Serovar Grippothy- posa. Resulting agglutination titers were read using dark field microscopy. Results: Confirmed leptospirosis was outlined as a ≥ 4-fold increase in microscopic agglutination test (MAT) titer. Out of 265 participants, 3.8% were exposed to Leptospira Serovar Gryppoty- phosa, 5.6% (15) had significant positive titer for Leptospira Serovar Gryppotyphosa. Apart from Leptospirosis; 13.8% of participants were malaria positive and 1.4% were brucellosis positive. Among those negative for malaria and brucellosis; 13 (5.7%) had high pos- itive titer for Leptospirosis. 2 participants were co- infected with malaria and Leptospirosis. This is just preliminary results, results of other serovars will be completed in December 2013 Conclusion: This study detected the circulating Leptospira Serovars in agro-pastoralist communities living in Katavi ecosys- tem. Serovar Gryppotyphosa is among the circulating Leptospira serovars in Katavi region. This information is significant for better understanding of epidemiology of Leptospirosis in Katavi Region. Molecular techniques like PCR, whole order sequencing ought to be thought of in future studies.