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Human leptospirosis in Tanzania: sequencing and phylogenetic analysis confirm that pathogenic Leptospira species circulate among agro-pastoralists living in Katavi-Rukwa ecosystem.
BMC Infect Dis 2016; 16:273BI

Abstract

BACKGROUND

Leptospirosis is a neglected zoonotic disease of worldwide public health importance. The disease affects humans, domestic animals and wildlife. However, leptospirosis is challenging in its diagnosis in humans. Culture technique, which is time consuming, is not recommended for clinical diagnosis. For these reasons, serological and molecular techniques remain the test of choice. The major objective of this study was to explore the genetic characteristic of Leptospira species which are prevalent among agro-pastoralists living in Katavi-Rukwa Ecosystem, Tanzania.

METHODS

A cross-sectional epidemiological study was carried out in the Katavi-Region South-west, Tanzania between August, 2013 and November, 2014. A total of 267 participants were randomly recruited for the study. Microscopic agglutination test (MAT) was used to detect antibody against six Leptospira antigens including local serogroups Icterohaemorrhagiae, Ballum, Grippotyphosa, Sejroe and reference serogroups Hebdomadis, and Australis. Samples with MAT titers ≥ 1:160 were scored as positive, samples with MAT titers ranging from 1:20 to 1:80 were scored as exposed to Leptospira, and absence of agglutination titers was scored as negative. All MAT positive samples, including the low titre samples were subjected to PCR using the respective 16S rRNA primers for the pathogenic and non-pathogenic species.

RESULTS

Out of 267 samples tested, 80 (29.9 %) were positive with MAT. The major circulating leptospiral serogroups were Sejroe (15.7 %,), Icterohaemorrhagiae (8.9 %), Grippotyphosa (4.8 %), Hebdomadis (3.37 %), Australis (1.49 %) and Ballum (1.19 %). By using PCR, 33 (15.7 %) out of 210 samples were pathogenic Leptospira while no saprophytic Leptospira spp. was detected. Partial 16S rRNA gene sequences of Leptospira species which were obtained from this study were submitted to GenBank and acquired accession numbers KP313246 and KP313247. Phylogenetic analysis of the nucleotide sequences revealed that species obtained from Katavi-Rukwa ecosystem clustered in the same group with several published pathogenic Leptospira specifically Leptospira interrogans and Leptospira kirschneri. To the best of the authors' knowledge(,) this is the first study from Tanzania to confirm pathogenic Leptospira in human subjects using genomic typing technique.

CONCLUSION

These findings provide ultimate evidence of pathogenic Leptospira species circulating among agro-pastoralists living in Katavi-Rukwa Ecosystem suggesting that active disease surveillance should be undertaken in order to achieve greater protection of the agro-pastoral communities in Tanzania.

Authors+Show Affiliations

Sokoine University of Agriculture, Morogoro, Tanzania. Shabanikmuller@yahoo.com. National Institute for Medical Research (NIMR), MOMS clinical Trial, Morogoro, Tanzania. Shabanikmuller@yahoo.com.Sokoine University of Agriculture, Morogoro, Tanzania.National Institute for Medical Research (NIMR), MOMS clinical Trial, Morogoro, Tanzania.Sokoine University of Agriculture, Morogoro, Tanzania.Sokoine University of Agriculture, Morogoro, Tanzania.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27287703

Citation

Muller, Shabani K., et al. "Human Leptospirosis in Tanzania: Sequencing and Phylogenetic Analysis Confirm That Pathogenic Leptospira Species Circulate Among Agro-pastoralists Living in Katavi-Rukwa Ecosystem." BMC Infectious Diseases, vol. 16, 2016, p. 273.
Muller SK, Assenga JA, Matemba LE, et al. Human leptospirosis in Tanzania: sequencing and phylogenetic analysis confirm that pathogenic Leptospira species circulate among agro-pastoralists living in Katavi-Rukwa ecosystem. BMC Infect Dis. 2016;16:273.
Muller, S. K., Assenga, J. A., Matemba, L. E., Misinzo, G., & Kazwala, R. R. (2016). Human leptospirosis in Tanzania: sequencing and phylogenetic analysis confirm that pathogenic Leptospira species circulate among agro-pastoralists living in Katavi-Rukwa ecosystem. BMC Infectious Diseases, 16, p. 273. doi:10.1186/s12879-016-1588-x.
Muller SK, et al. Human Leptospirosis in Tanzania: Sequencing and Phylogenetic Analysis Confirm That Pathogenic Leptospira Species Circulate Among Agro-pastoralists Living in Katavi-Rukwa Ecosystem. BMC Infect Dis. 2016 06 10;16:273. PubMed PMID: 27287703.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Human leptospirosis in Tanzania: sequencing and phylogenetic analysis confirm that pathogenic Leptospira species circulate among agro-pastoralists living in Katavi-Rukwa ecosystem. AU - Muller,Shabani K, AU - Assenga,Justine A, AU - Matemba,Lucas E, AU - Misinzo,Gerald, AU - Kazwala,Rudovick R, Y1 - 2016/06/10/ PY - 2015/10/21/received PY - 2016/05/21/accepted PY - 2016/6/12/entrez PY - 2016/6/12/pubmed PY - 2017/7/8/medline KW - Katavi-Rukwa Ecosystem KW - Leptospirosis KW - Phylogenetic Analysis KW - Sequencing KW - Tanzania SP - 273 EP - 273 JF - BMC infectious diseases JO - BMC Infect. Dis. VL - 16 N2 - BACKGROUND: Leptospirosis is a neglected zoonotic disease of worldwide public health importance. The disease affects humans, domestic animals and wildlife. However, leptospirosis is challenging in its diagnosis in humans. Culture technique, which is time consuming, is not recommended for clinical diagnosis. For these reasons, serological and molecular techniques remain the test of choice. The major objective of this study was to explore the genetic characteristic of Leptospira species which are prevalent among agro-pastoralists living in Katavi-Rukwa Ecosystem, Tanzania. METHODS: A cross-sectional epidemiological study was carried out in the Katavi-Region South-west, Tanzania between August, 2013 and November, 2014. A total of 267 participants were randomly recruited for the study. Microscopic agglutination test (MAT) was used to detect antibody against six Leptospira antigens including local serogroups Icterohaemorrhagiae, Ballum, Grippotyphosa, Sejroe and reference serogroups Hebdomadis, and Australis. Samples with MAT titers ≥ 1:160 were scored as positive, samples with MAT titers ranging from 1:20 to 1:80 were scored as exposed to Leptospira, and absence of agglutination titers was scored as negative. All MAT positive samples, including the low titre samples were subjected to PCR using the respective 16S rRNA primers for the pathogenic and non-pathogenic species. RESULTS: Out of 267 samples tested, 80 (29.9 %) were positive with MAT. The major circulating leptospiral serogroups were Sejroe (15.7 %,), Icterohaemorrhagiae (8.9 %), Grippotyphosa (4.8 %), Hebdomadis (3.37 %), Australis (1.49 %) and Ballum (1.19 %). By using PCR, 33 (15.7 %) out of 210 samples were pathogenic Leptospira while no saprophytic Leptospira spp. was detected. Partial 16S rRNA gene sequences of Leptospira species which were obtained from this study were submitted to GenBank and acquired accession numbers KP313246 and KP313247. Phylogenetic analysis of the nucleotide sequences revealed that species obtained from Katavi-Rukwa ecosystem clustered in the same group with several published pathogenic Leptospira specifically Leptospira interrogans and Leptospira kirschneri. To the best of the authors' knowledge(,) this is the first study from Tanzania to confirm pathogenic Leptospira in human subjects using genomic typing technique. CONCLUSION: These findings provide ultimate evidence of pathogenic Leptospira species circulating among agro-pastoralists living in Katavi-Rukwa Ecosystem suggesting that active disease surveillance should be undertaken in order to achieve greater protection of the agro-pastoral communities in Tanzania. SN - 1471-2334 UR - https://www.unboundmedicine.com/medline/citation/27287703/Human_leptospirosis_in_Tanzania:_sequencing_and_phylogenetic_analysis_confirm_that_pathogenic_Leptospira_species_circulate_among_agro_pastoralists_living_in_Katavi_Rukwa_ecosystem_ L2 - https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-016-1588-x DB - PRIME DP - Unbound Medicine ER -