Mycobacteria in Terrestrial Small Mammals on Cattle Farms in Tanzania

The control of bovine tuberculosis and atypical mycobacterioses in cattle in developing countries is important but difficult because of the existence of wildlife reservoirs. In cattle farms in Tanzania, mycobacteria were detected in 7.3% of 645 small mammals and in cow's milk. The cattle farms were divided into “reacting” and “nonreacting” farms, based on tuberculin tests, and more mycobacteria were present in insectivores collected in reacting farms as compared to nonreacting farms. More mycobacteria were also present in insectivores as compared to rodents. All mycobacteria detected by culture and PCR in the small mammals were atypical mycobacteria. Analysis of the presence of mycobacteria in relation to the reactor status of the cattle farms does not exclude transmission between small mammals and cattle but indicates that transmission to cattle from another source of infection is more likely. However, because of the high prevalence of mycobacteria in some small mammal species, these infected animals can pose a risk to humans, especially in areas with a high HIV-prevalence as is the case in Tanzania

Prevalence and factors associated with of bovine leptospirosis in small scale dairy farms in Tanga region, Tanzania

PREVALENCE ET FACTEURS LIES A LA LEPTOSPIROSE BOVINE DANS DES PETITES EXPLOITATIONS DE FERMES LAITIERES DANS LA REGION DE TANGA EN TANZANIE Résumé Des prélèvements de sérum à des bovins laitiers croisés (n = 230) issus de 120 fermes choisies au hasard dans la région de Tanga ont été testés en vue de déterminer la présence des anticorps contre les leptospires pendant la période janvier - avril 1999. Les prélèvements de sérum étaient examinés à l\'aide d\'un test d\'agglutination microscopique (TAM) contre 5 sérovars de Leptospira interrogans. Vingt-et-une (21) des 120 fermes 17,5% [ Intervalle de confiance (IC) 95% = 11,2 ; 25,3)] avaient au moins un animal positif pour un ou deux sérotypes de leptospire et 10,8% [ IC 95% = 7,15 ; 15,62] des animaux examinés étaient positifs pour la leptospirose. Les anticorps les plus fréquents détectés étaient ceux contre les antigènes de sérovars Tarassovi (44%), Hardjo (32%), Pomona (12%), Bataviae (8%) et Grippotyphosa (4%). En utilisant des modèles à effet mixte (avec une ferme comme facteur aléatoire), l\'animal dans le district de Lushoto et la race zébu étaient liés à la baisse de risque de séropositivité [ratio de probabilité (RP) = 0,12 ; P = 0,050 pour l\'animal de Lushoto et RP = 0,31 ; P = 0,019 pour la race zébu, respectivement]. En revanche, la race Boran était identifiée comme étant un facteur de risque à la leptospirose (RP = 2,7 ; P = 0,050). La séroprévalence est probablement due à une exposition aux leptospires par le passé ou à l\'infection asymptomatique par la leptospirose parce que l\'on n\'a pas effectué de vaccination contre la leptospirose dans la région de Tanga. Mots-clés : Leptospirose, épidémiologie, séroprévalence, facteurs de risque, petite exploitation, bétail laitier, Tanga, Tanzanie. Summary Cross-bred dairy cattle serum samples (n =230) from 120 hundred randomly selected farms in the Tanga region were tested for the presence of leptospira antibodies during the period January to April 1999. Serum samples were screened using microscopic agglutination test (MAT) against 5 serovars of Leptospira interrogans. Twenty-one (17.5%, 95% Confidence interval [CI] = 11.2, 25.3) of the farms had at least one individual animal positive for one or two of the leptospira serotype and 10.8 %( 95%CI = 7.15, 15.62) of the animals were positive for leptospirosis. The most common antibodies detected were those against antigens of serovars Tarassovi (44%), Hardjo (32%), Pomona (12%), Bataviae (8%) and Grippotyphosa (4%). Using mixed-effect models (with farm as a random effect), animal located in Lushoto district and Zebu breed were associated with decreased risk of seropositivity (Odd ratio [OR] = 0.12, P = 0.050 for Lushoto and OR = 0.31, P = 0.019 for Zebu, respectively). Boran breed was identified as a risk factor to leptospirosis (OR = 2.7, P = 0.050). The seroprevalence probably reflects a past exposure to leptospiral organisms or asymptomatic leptospirosis infection because vaccination against leptosprosis has not been practiced in Tanga region. Keywords: Leptospirosis, epidemiology, seroprevalence, risk factors, smallholder, dairy cattle, Tanga, Tanzania Bull Anim. Hlth. Prod. Afr. (2004) 53, 51-5

New Leptospira serovar Sokoine of serogroup Icterohaemorrhagiae from cattle in Tanzania

The prevalence of leptospirosis is generally high in domestic animals and rodents in Tanzania. Identification of Leptospira isolates from cattle was carried out to establish prevalent Leptospira serovars. Serological typing was done based on monoclonal antibodies and the standard cross-agglutination absorption test. Molecular typing involved pathogenic- and saprophytic-specific PCRs and a PCR specifically amplifying DNA from the species Leptospira kirschneri. DNA fingerprinting with primers derived from sequences of insertion elements IS1500 and IS1533 was carried out. Both serological and molecular characterization indicated that one of the Leptospira isolates, coded RM1, represents a new serovar of the species L. kirschneri of serogroup Icterohaemorrhagiae. The serovar name Sokoine is proposed for this new Leptospira isolat

The prevalence of Mycobacterium bovis-infection and atypical mycobacterioses in cattle in and around Morogoro, Tanzania

A study was conducted to determine the prevalence of Mycobacterium bovis-infection and atypical mycobacterioses in different cattle herd management systems in and around Morogoro, Tanzania. Between April and June 2005, a total of 728 bovines from 49 herds were tested for M. bovis-infection and atypical mycobacterioses. Milk samples were taken from tuberculin positive animals and analysed for the presence of mycobacteria. Total prevalences of 2.5% and 10.1% were found for M. bovis-infection and atypical mycobacterioses respectively, with more M. bovis-infection in cattle in the extensive management system and more atypical mycobacterioses in cattle in the intensive management system. From 8 out of 42 milk samples (19%) atypical mycobacteria were cultured. A higher prevalence of M. bovis-infection in the extensive sector could be due to several factors. In addition, such high prevalence puts herd owners and their families at risk for BTB. Therefore control of BTB, as well as education of cattle owners is important, especially in the extensive sector

Multilocus sequence typing method for identification and genotypic classification of pathogenic Leptospira species

Annals of Clinical Microbiology and Antimicrobials 2006, Vol. 5:28Leptospira are the parasitic bacterial organisms associated with a broad range of mammalian hosts and are responsible for severe cases of human Leptospirosis. The epidemiology of leptospirosis is complex and dynamic. Multiple serovars have been identified, each adapted to one or more animal hosts. Adaptation is a dynamic process that changes the spatial and temporal distribution of serovars and clinical manifestations in different hosts. Serotyping based on repertoire of surface antigens is an ambiguous and artificial system of classification of leptospiral agents. Molecular typing methods for the identification of pathogenic leptospires up to individual genome species level have been highly sought after since the decipherment of whole genome sequences. Only a few resources exist for microbial genotypic data based on individual techniques such as Multiple Locus Sequence Typing (MLST), but unfortunately no such databases are existent for leptospires. We for the first time report development of a robust MLST method for genotyping of Leptospira. Genotyping based on DNA sequence identity of 4 housekeeping genes and 2 candidate genes was analyzed in a set of 120 strains including 41 reference strains representing different geographical areas and from different sources. Of the six selected genes, adk, icdA and secY were significantly more variable whereas the LipL32 and LipL41 coding genes and the rrs2 gene were moderately variable. The phylogenetic tree clustered the isolates according to the genome-based species. The main advantages of MLST over other typing methods for leptospires include reproducibility, robustness, consistency and portability. The genetic relatedness of the leptospires can be better studied by the MLST approach and can be used for molecular epidemiological and evolutionary studies and population genetics

Multilocus sequence typing method for identification and genotypic classification of pathogenic Leptospira species

Annals of Clinical Microbiology and Antimicrobials 2006, Vol. 5:28Leptospira are the parasitic bacterial organisms associated with a broad range of mammalian hosts and are responsible for severe cases of human Leptospirosis. The epidemiology of leptospirosis is complex and dynamic. Multiple serovars have been identified, each adapted to one or more animal hosts. Adaptation is a dynamic process that changes the spatial and temporal distribution of serovars and clinical manifestations in different hosts. Serotyping based on repertoire of surface antigens is an ambiguous and artificial system of classification of leptospiral agents. Molecular typing methods for the identification of pathogenic leptospires up to individual genome species level have been highly sought after since the decipherment of whole genome sequences. Only a few resources exist for microbial genotypic data based on individual techniques such as Multiple Locus Sequence Typing (MLST), but unfortunately no such databases are existent for leptospires. We for the first time report development of a robust MLST method for genotyping of Leptospira. Genotyping based on DNA sequence identity of 4 housekeeping genes and 2 candidate genes was analyzed in a set of 120 strains including 41 reference strains representing different geographical areas and from different sources. Of the six selected genes, adk, icdA and secY were significantly more variable whereas the LipL32 and LipL41 coding genes and the rrs2 gene were moderately variable. The phylogenetic tree clustered the isolates according to the genome-based species. The main advantages of MLST over other typing methods for leptospires include reproducibility, robustness, consistency and portability. The genetic relatedness of the leptospires can be better studied by the MLST approach and can be used for molecular epidemiological and evolutionary studies and population genetics