Tuberculosis cross-species transmission in Tanzania: towards a One-Health concept

Prioritization of neglected tropical zoonotic diseases: A one health perspective from Tigray region, Northern Ethiopia

Neglected tropical zoonotic diseases (NTZDs) continue to have a major effect on the health of humans and animals. In this study, a one health approach was used to prioritize and rank neglected tropical zoonotic diseases at the regional and zonal levels in Tigray National Regional State, Ethiopia. For prioritization of NTZDs a cross-sectional study through a structured questionnaire was administered to 313 health experts from human and animal health sectors. In addition, focus group discussions (FGD) were held with purposively selected key informants. Descriptive, and Multivariable analysis was applied to report the results and a ranked list of diseases was developed at the zonal and regional level. In the region, 8 of the 12 World Health Organization listed NTZDs were considered major diseases including anthrax, brucellosis, bovine tuberculosis, taeniasis, leishmaniasis, rabies, schistosomiasis, and soil-transmitted helminths. Considering the zoonotic and socioeconomic importance of the diseases at the regional level, rabies ranked 1^stwhereas anthrax, bovine tuberculosis, leishmaniasis, and brucellosis were ranked from 2^nd to 5^th, respectively. The FGD result also supported the prioritization result. The Multivariable analysis showed a statistically significant difference in the zonal distribution of anthrax (р = 0.009, OR = 1.16), taeniasis (p<0.001, OR = 0.82), leishmaniasis (p<0.001, OR = 1.91), rabies (p = 0.020, OR = 0.79) and soil-transmitted helminths (p = 0.007, OR = 0.87) but not for brucellosis (p = 0.585), bovine tuberculosis (p = 0.505), and schistosomiasis (p = 0.421). Anthrax (p<0.001, OR = 26.68), brucellosis (p<0.001, OR = 13.18), and taeniasis (p<0.001, OR = 6.17) were considered as the major zoonotic diseases by veterinary practitioners than human health practitioners whereas, leishmaniasis was recognized as a major health challenge by human health professionals. Understanding the priority diseases in the region is supportive for informed decision-making and prioritizes the limited resources to use. Furthermore, strengthening the collaboration between human and animal health professions is important to control the diseases.

Isolation, identification and associated risk factors of non-tuberculous mycobacteria infection in humans and dromedary camels in Samburu County, Kenya

Non-tuberculous mycobacteria are of public health significance, and zoonotic infection is attributed to the sociocultural practice of consumption of raw milk and the close human-livestock contact in pastoral communities. This study aimed at isolation, identification of mycobacteria from human sputum and camel milk and risk factors assessment in Samburu East, Kenya. Six hundred and twelve camels and 48 people presumed to have tuberculosis (TB) from 86 households in Wamba and Waso regions were screened. Camels were categorized into Somali, Turkana and Rendile breeds. Single intradermal comparative tuberculin test (SICTT) was used as a herd-screening test on lactating camels and a milk sample collected from reactive camels. Sputum samples were collected from eligible members of participating households. A standard questionnaire on possible risk factors for both humans and camels was administered to respective household heads or their representatives. Total camel skin test reactors were 238/612 (38.9%). Milk and sputum samples were analysed at KEMRI/TB research laboratory for microscopy, GeneXpert^® , culture and identification. Isolates were identified using 16S rRNA gene sequencing at Inqaba biotec in South Africa. Sixty-four isolates were acid-fast bacilli (AFB) positive of which M. fortuitum (3), M. szulgai (20), M. monacense (5), M. lehmanni (4), M. litorale (4), M. elephantis (3), M. duvalii (3), M. brasiliensis (1), M. arcueilense (1) and M. lentiflavum (1) were from milk; M. fortuitum (1), M. szulgai (2) and M. litorale (1) were from humans. Risk factors included the following: Turkana breed (OR = 3.4; 95% CI: 1.2-9.3), replacements from outside the County (OR = 2.1; 95% CI: 0.3-12.3), presence of other domestic species (small stock; OR = 4.6) and replacement from within the herd (OR = 3.2; 95% CI: 0.7-14.7). Zoonotic risk practices included raw milk consumption, shared housing and handling camels. Monitoring of zoonotic NTM through surveillance and notification systems is required.

Bovine tuberculosis in eastern Ethiopia: prevalence, risk factors and its public health importance

BACKGROUND

Bovine tuberculosis is among the primary zoonotic disease caused by Mycobacterium bovis which has significant impact on the health of livestock and human. It has been significantly a cause for great economic loss in animal production.

METHODOLOGY

A cross-sectional study was conducted from December 2014 to June 2016 on 315 cattle in selected areas of eastern Ethiopia, aiming to estimate the occurrence of bovine tuberculosis using comparative intradermal tuberculin skin test and assess cattle owners' awareness on its public health implication. Random sampling method was applied in order to select animals from farm/household and associated risk factors were recorded before purified protein derivative (PPD) injection. Forty three farm/household owners of tuberculin tested animals were interviewed using pre-tested structured questionnaires.

RESULTS

The overall prevalence of bovine tuberculosis was 20.3% (n = 64) in dairy cattle at recommended cut off > 4 mm. From a total of 43 farms/households tested, 22 were positive; each farm exhibited at least one tuberculin positive reactor animal with a total herd level prevalence of 51.2%. The prevalence of bovine tuberculosis in individual animal level was significantly different (χ2 = 45.2; P-value = 0.000) in different sites with a higher prevalence (50%) in Dire Dawa. Farming system, herd size and other risk factors were significantly (p < 0.05) associated with bovine tuberculosis occurrence. Of the total interviewed farm owners, only 33% had the knowledge of or had heard about bovine tuberculosis and 23% respondents were aware of the zoonotic importance of the disease. More than 50% of the interviewees had shown their preference of raw milk consumption. Out of the total interviewed households, 3 (7%) farm workers had TB cases that had direct contact with the animals.

CONCLUSION

The study showed bovine tuberculosis is highly prevalent. Associated risk factors contributed to the prevalence of the disease in cattle and its transmission. Moreover, the majority of cattle owners lack awareness about the disease and its public health significance. Awareness rising about the disease, its transmission and zoonotic implication is of great importance for reduction and control measures. Evidence of tuberculosis patient farm attendants calls also for further detail investigation.

Mapping of Mycobacterium tuberculosis Complex Genetic Diversity Profiles in Tanzania and Other African Countries

The aim of this study was to assess and characterize Mycobacterium tuberculosis complex (MTBC) genotypic diversity in Tanzania, as well as in neighbouring East and other several African countries. We used spoligotyping to identify a total of 293 M. tuberculosis clinical isolates (one isolate per patient) collected in the Bunda, Dar es Salaam, Ngorongoro and Serengeti areas in Tanzania. The results were compared with results in the SITVIT2 international database of the Pasteur Institute of Guadeloupe. Genotyping and phylogeographical analyses highlighted the predominance of the CAS, T, EAI, and LAM MTBC lineages in Tanzania. The three most frequent Spoligotype International Types (SITs) were: SIT21/CAS1-Kili (n = 76; 25.94%), SIT59/LAM11-ZWE (n = 22; 7.51%), and SIT126/EAI5 tentatively reclassified as EAI3-TZA (n = 18; 6.14%). Furthermore, three SITs were newly created in this study (SIT4056/EAI5 n = 2, SIT4057/T1 n = 1, and SIT4058/EAI5 n = 1). We noted that the East-African-Indian (EAI) lineage was more predominant in Bunda, the Manu lineage was more common among strains isolated in Ngorongoro, and the Central-Asian (CAS) lineage was more predominant in Dar es Salaam (p-value<0.0001). No statistically significant differences were noted when comparing HIV status of patients vs. major lineages (p-value = 0.103). However, when grouping lineages as Principal Genetic Groups (PGG), we noticed that PGG2/3 group (Haarlem, LAM, S, T, and X) was more associated with HIV-positive patients as compared to PGG1 group (Beijing, CAS, EAI, and Manu) (p-value = 0.03). This study provided mapping of MTBC genetic diversity in Tanzania (containing information on isolates from different cities) and neighbouring East African and other several African countries highlighting differences as regards to MTBC genotypic distribution between Tanzania and other African countries. This work also allowed underlining of spoligotyping patterns tentatively grouped within the newly designated EAI3-TZA lineage (remarkable by absence of spacers 2 and 3, and represented by SIT126) which seems to be specific to Tanzania. However, further genotyping information would be needed to confirm this specificity.

Identificação e genotipagem de Mycobacterium bovis em bovinos positivos no teste intradérmico para tuberculose em Mato Grosso do Sul

Neste estudo, realizou-se genotipagem de isolados de Mycobacterium bovis, provenientes de amostras de tecidos de bovinos positivos no teste cervical comparativo (TCC) para tuberculose em Mato Grosso do Sul, por meio da técnica de spoligotyping. Tecidos de 13 bovinos positivos, oriundos de diferentes municípios do estado, foram cultivados em meio de Stonebrink. As colônias resultantes foram submetidas à coloração de Ziehl-Neelsen e todos os isolados apresentaram características tintoriais de BAAR. Os 13 isolados de BAAR foram identificados por PCR multiplex (mPCR). O gene hsp65 foi alvo para identificação de Mycobacterium spp, a sequência de inserção IS6110 foi alvo para identificação de complexo Mycobacterium tuberculosis (CMT) e a região rvd1rv2031c foi explorada para detecção de M. bovis. Os isolados micobacterianos foram genotipados pela técnica de spoligotyping. Dos 13 bovinos, sete tinham pelo menos uma lesão sugestiva de tuberculose em linfonodos retrofaríngeos, parotídeos e pulmonares ou no pulmão, e em seis não foram encontradas lesões visíveis sugestivas da doença. Na mPCR, 11/13 (84,6%) isolados foram positivos para Mycobacterium spp; 8/13 (61,5%) positivos para CMT e 7/13 (53,8%) positivos para M. bovis. Com base no spoligotyping, oito isolados de BAAR foram agrupados dentro de três diferentes agrupamentos de genótipos e uma amostra remanescente apresentou perfil único, sendo quatro isolados com padrão de espoligotipo SB0121, dois SB1145, dois SB0881 e um SB0140. A técnica de spoligotyping demonstrou que há diversidade genética entre os espoligotipos presentes no estado de Mato Grosso do Sul, embora predomine o perfil SB0121

Detection of Mycobacterium bovis in bovine and bubaline tissues using nested-PCR for TbD1

In the present study, a nested-PCR system, targeting the TbD1 region, involving the performance of conventional PCR followed by real-time PCR, was developed to detect Mycobacterium bovis in bovine/bubaline tissue homogenates. The sensitivity and specificity of the reactions were assessed with DNA samples extracted from tuberculous and non-tuberculous mycobacteria, as well as other actinomycetales species and DNA samples extracted directly from bovine and bubaline tissue homogenates. In terms of analytical sensitivity, the DNA of M. bovis AN5 was detected up to 1.56 ng with conventional PCR, 97.6 pg with real-time PCR, and 1.53 pg with nested-PCR in the reaction mixture. The nested-PCR exhibited 100% analytical specificity for M. bovis when tested with the DNA of reference strains of environmental mycobacteria and closely-related Actinomycetales. A clinical sensitivity value of 76.0% was detected with tissue samples from animals that exhibited positive results in the comparative intradermal tuberculin test (CITT), as well as from those with lesions compatible with tuberculosis (LCT) that rendered positive cultures. A clinical specificity value of 100% was detected with tissue samples from animals with CITT- results, with no visible lesions (NVL) and negative cultures. No significant differences were found between the nested-PCR and culture in terms of detecting CITT+ animals with LCT or with NVL. No significant differences were recorded in the detection of CITT- animals with NVL. However, nested-PCR detected a significantly higher number of positive animals than the culture in the group of animals exhibiting LCT with no previous records of CITT. The use of the nested-PCR assay to detect M. bovis in tissue homogenates provided a rapid diagnosis of bovine and bubaline tuberculosis.

Molecular characterization of Mycobacterium bovis isolates from pastoral livestock at Mikumi-Selous ecosystem in the eastern Tanzania

Domestic ruminants and Wild ungulates can act as reservoir hosts for Mycobacterium bovis, causative agent for bovine tuberculosis (BTB) in animals and man. Bovine tuberculosis (BTB) is endemic in pastoral livestock in Tanzania. There is lack of information on genotypic distribution of M. bovis in animals at wildlife-livestock interface areas and in wildlife conserved areas. The objectives of this study were to characterize and determine the spatial distribution of M. bovis isolates. Tissue samples from cattle and wildlife were cultured and analyzed using deletion typing and spoligotyping techniques. Eight (8.9%) M. bovis strains were isolated from cattle and confirmed by RD4 and RD9 polymerize chain reaction (PCR) assays. Spoligotype SB1467 was the dominant pattern 62.5% (n = 8) in infected animals, two isolates belonged to a newly reported type SB2190, and one isolate belonged to SB0133. The spoligotype patterns of SB1467 and SB0133 were closely related (96.9%) while SB2190 was less related (59.4%) to SB0133, the relatedness amongst spoligotypes were associated with spacer position 15. No M. bovis was isolated from hunted wild animals. The current study has identified a novel spoligotype SB2190. The current data suggest that wild animals in Mikumi-Selous ecosystem are at risk of acquiring M. bovis infection due to occasional interaction by sharing of pasture and water sources between wildlife and livestock. Integrated efforts by all stakeholders are crucial for controlling spread of tuberculosis at livestock/wildlife/human interface areas.

Prevalence and significant geospatial clusters of bovine tuberculosis infection at livestock-wildlife interface ecosystem in Eastern Tanzania

Bovine tuberculosis (BTB) is an important neglected zoonosis that affects livestock, wildlife and human. A study to determine prevalence and geospatial clusters for BTB was conducted from June 2010 to March 2012 at livestock-wildlife interface areas (LWIA). A total of 1,288 cattle located in vicinity of Mikumi-Selous ecosystem Tanzania were tested. Single Intradermal Comparative Tuberculin Test and spatial scan statistic analysis were applied to establish the status of the disease and identify significant spatial BTB clusters. Overall individual prevalence was 3.7 % (n=1,288) (95 % CI=2.8-4.9) and 7.8 % (95 % CI=6.4-9.4) with cut-off of >4 and >2 mm, respectively. Villages with at least one reactor were 55.8 % (n=43). Reactivity was significantly higher in Mvomero and Kilosa districts compared with Kilombero and Ulanga districts (χ (2) =15.9; P<0.001). Significant spatial BTB clusters were revealed at 11 villages. BTB clustering was significant in Kilosa and Mvomero districts compared with Kilombero and Ulanga districts. There was overlap and aggregation of BTB clusters covering south and south-east of Kilosa district bordering Mikumi National Park (MNP) and Mvomero. Generally, clustering occurred around major rivers. The current study provides useful information on the dynamics and epidemiological status of BTB around the wildlife-livestock-human interface, it reveals that the wildlife are at risk of BTB from infected livestock. The study revealed hotspots for BTB that can be applied to guide implementation of participatory intervention at LWIA and control strategies in marginalised pastoralist communities. This study calls for similar studies in other Tanzania's LWIA for efficient intervention of BTB countrywide.