Yes / Buruli ulcer (BU) is an insidious neglected tropical disease. Cases are reported around the world but the rural regions of West and Central Africa are most affected. How BU is transmitted and spreads has remained a mystery, even though the causative agent, Mycobacterium ulcerans, has been known for more than 70 years. Here, using the tools of population genomics, we reconstruct the evolutionaryhistoryofM. ulceransbycomparing165isolatesspanning48yearsandrepresenting11endemiccountriesacrossAfrica. The genetic diversity of African M. ulcerans was found to be restricted due to the bacterium’s slow substitution rate coupled with its relatively recent origin. We identified two specific M. ulcerans lineages within the African continent, and inferred that M. ulcerans lineage Mu_A1 existed in Africa for several hundreds of years, unlike lineage Mu_A2, which was introduced much more recently, approximately during the 19th century. Additionally, we observed that specific M. ulcerans epidemic Mu_A1 clones were introduced during the same time period in the three hydrological basins that were well covered in our panel. The estimated time span of the introduction events coincides with the Neo-imperialism period, during which time the European colonial powers divided the African continent among themselves. Using this temporal association, and in the absence of a known BU reservoir or—vector on the continent, we postulate that the so-called "Scramble for Africa" played a significant role in the spread of the disease across the continent. / K.V. was supported by a PhD-grant of the Flemish Interuniversity Council—University Development Cooperation (Belgium). B.d.J. and C.M. were supported by the European Research Council-INTERRUPTB starting grant (no. 311725). T.P.S. was supported by a fellowship from the National Health and Medical Research Council of Australia (1105525). Funding for this work was provided by the Department of Economy, Science and Innovation of the Flemish Government, the Stop Buruli Consortium supported by the UBS Optimus Foundation, and the Fund for Scientific Research Flanders (Belgium) (FWO grant no. G.0321.07N). The computational resources used in this work were provided by the HPC core facility CalcUA and VSC (Flemish Supercomputer Center), funded by the University of Antwerp, the Hercules Foundation and the Flemish Government—department EWI. Aspects of the research in Cameroon and Benin were funded by the Raoul Follereau Fondation France.

Anthropozoonotic diseases, defined as infectious diseases caused by pathogens transmitted from humans to wildlife, pose a significant health threat to wildlife populations. Many of these pathogens are also able to move from wildlife reservoirs to humans, termed zoonotic diseases, creating the possibility for bi-directional transmission between humans and wildlife. Recent studies show that a significant proportion of emerging infectious diseases in humans originate in wildlife reservoirs and that the frequency of emergence is increasing, yet the specific transmission pathways still remain speculative in most cases. Human fecal waste is persistent across human-modified landscapes and has been identified as a potential source of disease exposure for wildlife populations living near humans. As part of a long-term study of banded mongoose (Mungos mungo) that live in close association with humans and human fecal waste I used Escherichia coli and banded mongoose (Mungos mungo) for evaluating exchange of fecal waste-borne microorganisms at the human-wildlife interface. Antibiotic resistance was found in 57.5% ° 10.3% (n=87) of mongoose fecal samples and 37.2% ° 5.9% of isolates (n=253). Multidrug resistance was detected in 13.8% ° 4.2% of isolates (n=253). Mongoose and human fecal waste isolates consistently clustered together in phylogenetic analyses and statistical analysis of genetic variation showed no significant differences (p=0.18) between E. coli from human and mongoose populations. These results suggest that human fecal waste contamination is an important mechanism for the transmission of pathogens to both humans and animals, including the spread of antibiotic resistance in the environment, an emerging global health threat. / Master of Science

abstract: Epidemiological theory normally does not predict host extinction from infectious disease because of a host density threshold below which pathogens cannot persist. However, host extinction can occur when a biotic or abiotic pathogen reservoir allows for density-independent transmission. Amphibians are facing global population decline and extinction from the emerging infectious disease chytridiomycosis, caused by the fungus Batrachochytrium dentrobatidis (Bd). I use the model species Eleutherodactylus coqui to assess the impact of Bd on terrestrial direct-developing frog species, a common life history in the tropics. I tested the importance of two key factors that might influence this impact and then used laboratory experiments and published field data to model population-level impacts of Bd on E. coqui. First, I assessed the ontogenetic susceptibility of E. coqui by exposing juvenile and adult frogs to the same pathogen strain and dose. Juveniles exposed to Bd had significantly lower survival rates compared with control juveniles, while adult frogs often cleared infection. Second, I conducted experiments to determine whether E. coqui can become infected with Bd indirectly from contact with zoospores shed onto vegetation by an infected frog and from direct exposure to an infected frog. Both types of transmission were observed, making this the first demonstration that amphibians can become infected indirectly in non-aquatic habitats. Third, I tested the hypothesis that artificially-maintained cultures of Bd attenuate in pathogenicity, an effect known for other fungal pathogens. Comparing two cultures of the same Bd strain with different passage histories revealed reduced zoospore production and disease-induced mortality rates for a susceptible frog species (Atelopus zeteki) but not for the less-susceptible E. coqui. Finally, I used a mathematical model to project the population-level impacts of chytridiomycosis on E. coqui. Model analysis showed that indirect transmission, combined with either a high rate of zoospore production or low rate of zoospore mortality, is required for Bd to drive E. coqui populations below an extinction threshold. High rates of transmission plus frequent re-infection could lead to poor recruitment of infected juveniles and population decline. My research adds further insight into how emerging infectious disease is contributing to the loss of amphibian biodiversity. / Dissertation/Thesis / Ph.D. Biology 2013

Yes / Buruli ulcer is a neglected tropical disease of skin and subcutaneous tissue caused by infection with the pathogen Mycobacterium ulcerans. Many critical issues for disease control, such as understanding the mode of transmission and identifying source reservoirs of M. ulcerans, are still largely unknown. Here, we used genomics to reconstruct in detail the evolutionary trajectory and dynamics of M. ulcerans populations at a central African scale and at smaller geographical village scales. Whole-genome sequencing (WGS) data were analyzed from 179 M. ulcerans strains isolated from all Buruli ulcer foci in the Democratic Republic of the Congo, The Republic of Congo, and Angola that have ever yielded positive M. ulcerans cultures. We used both temporal associations and the study of the mycobacterial demographic history to estimate the contribution of humans as a reservoir in Buruli ulcer transmission. Our phylogeographic analysis revealed one almost exclusively predominant sublineage of M. ulcerans that arose in Central Africa and proliferated in its different regions of endemicity during the Age of Discovery. We observed how the best sampled endemic hot spot, the Songololo territory, became an area of endemicity while the region was being colonized by Belgium (1880s). We furthermore identified temporal parallels between the observed past population fluxes of M. ulcerans from the Songololo territory and the timing of health policy changes toward control of the Buruli ulcer epidemic in that region. These findings suggest that an intervention based on detecting and treating human cases in an area of endemicity might be sufficient to break disease transmission chains, irrespective of other reservoirs of the bacterium.

No description available.

Infectious disease transmission is driven by a complex suite of drivers with behavior and landscape dynamics contributing to epidemics across host-pathogen systems. However, our understanding of the interaction between landscape, behavior, and infectious disease remains limited. In the banded mongoose (Mungos mungo), a novel tuberculosis pathogen, Mycobacterium mungi, has emerged in Northern Botswana that is transmitted through olfactory communication behaviors. Using this host-pathogen system, this thesis explores the influence of various land use areas along the human-wildlife interface on animal behavior, and ultimately, pathogen transmission potential. Using behavior data from remote sensing camera traps, a generalized linear mixed model identified vigilance behavior, land use, and their interaction as important factors in predicting olfactory behavior. Cluster and Classification and Regression Tree (CART) analysis of active den sites (n= 308, across 23 troops) identified the important characteristics of dens across land use areas. In human-modified environments, man-made den sites persisted longer than did natural dens which became unsuitable through environmental processes (e.g., collapse). We also document the occurrence of nighttime activity for this species, perceived to be strictly diurnal. These data provide information critical to the development of robust computational models and underscore the importance of both landscape and behavior in accurately predicting and managing infectious disease outbreaks. / M. S.

As brássicas compreendem diversas espécies de grande relevância comercial dentre as demais espécies olerícolas cultivadas no Brasil. A região localizada próxima à cidade de São Paulo (SP) tem se destacado no cultivo de brássicas, especialmente do repolho, da couve-flor e do brócolis. Em campos de cultivo destas espécies, tem sido observadas plantas exibindo redução de tamanho, inflorescências mal formadas, avermelhamento de folhas e necrose dos vasos condutores. Investigações tem mostrado que estas anormalidades estão associadas aos fitoplasmas e a doença tem sido denominada enfezamento. Ainda, estudos anteriores têm sugerido a ocorrência de algumas espécies de cigarrinhas potencialmente vetoras destes fitoplasmas. Considerando estas informações, o presente trabalho teve por objetivo identificar espécies transmissoras de fitoplasmas para plantas de brócolis, buscando aumentar os conhecimentos sobre os vetores de fitoplasmas envolvidos com o enfezamento desta cultura. Para isto, foram coletados insetos no interior e áreas marginais de campos cultivados. Estes insetos foram separados em grupos, identificados taxonomicamente e confinados em plantas sadias de brócolis. A avaliação da transmissão foi feita com base na detecção de fitoplasmas nos tecidos dos insetos e das plantas, usando-se a técnica de PCR duplo, com primers específicos para identificação de fitoplasmas do grupo 16SrIII. A sobrevivência dos insetos nas plantas de brócolis foi pouco duradoura, não excedendo 48 horas. A transmissão experimental foi constatada em 30% das plantas inoculadas. Dentre as 8 potenciais espécies de vetores que foram testadas, as espécies Atanus nitidus, Balclutha hebe, Agalliana sticticollis e Agallia albidula transmitiram fitoplasma para plantas de brócolis. Os resultados deste estudo confirmaram aqueles obtidos nas investigações anteriores, as quais sugeriam a ocorrência de potenciais espécies vetoras de fitoplasmas dentre aquelas presentes nos campos de cultivo. No entanto, o conhecimento de detalhes sobre a transmissão necessita de estudos com populações sadias e infectivas das espécies vetoras, sob condições controladas. Apesar desta necessidade, uma etapa importante foi cumprida no presente trabalho, o qual se constitui numa contribuição relevante tanto para o conhecimento de aspectos epidemiológicos relacionados à disseminação do agente causal do enfezamento do brócolis como para a área de conhecimento relacionada à transmissão de patógenos por insetos vetores, nas condições brasileiras. / Cole crops include several species of commercial importance among the vegetable crops cultivated in Brazil. The region located near the city of São Paulo (SP) has excelled in the cultivation of brassica, especially cabbage, cauliflower and broccoli. In cultivated fields with these species have been observed plants showing reduction of size, malformed inflorescences, reddening of leaves and necrosis of region of vessels. Previous investigations have shown that these abnormalities are associated with phytoplasmas and the disease has been called stunt. In addition, previous studies have suggested the occurrence of some species of leafhoppers potentially vectors of phytoplasmas. Considering this information, the present study aimed to identify species that transmit phytoplasmas to plants of broccoli, seeking to increase knowledge about vectors of phytoplasmas involved with this culture. Thus, insects were collected within and in marginal areas of cultivated fields. These insects were separated into groups, taxonomically identified and confined in healthy plants of broccoli. The evaluation of transmission was based on detection of phytoplasmas in the tissues of plants and insects using the technique of nested PCR with specific primers for identification of phytoplasmas group 16SrIII. The survival of insects on plants of broccoli was short-lived, not exceeding 48 hours. The experimental transmission was observed in 30% of inoculated plants. Among the 8 potential vector species that were tested, the species Atanus nitidus, Balclutha hebe, Agalliana sticticollis and Agallia albidula transmitted phytoplasma to plants of broccoli. The results of the present study confirmed those obtained in previous research, which suggested the occurrence of potential vector species of phytoplasmas among those present in crop fields. However, details about these species as vectors require the creation of healthy populations of these species and infective for broadcast demonstration in controlled conditions. Despite this need, an important step has been accomplished in this work, which constitutes a significant contribution both to the knowledge of epidemiological aspects related to the spread of causal agent of broccoli stunt and the area of knowledge related to the transmission of pathogens by insects vectors, the Brazilian conditions.

<p>Background. Platelets (thrombocytes) are the smallest cells in the blood. Platelet fulfils functions as formation of blood clots when bleeding. Low levels leads to bleeding while high levels increase the risk of thrombosis (obstruction of the circulatory flow system). Platelet transfusions may be required for patients with systemic bleeding and for patients at higher risk of bleeding because of coagulation defects, sepsis (presence of bacteria in the bloodstream), or platelet dysfunction related to medication or disease. A pathogen-reduction system for platelet components would be a useful method since it reduces the risk of bacterial, protozoa, viral and white blood cell contamination. The Intercept Blood System method (IBS) for platelets, destroys DNA and RNA and was validated against the routine method in order to reduce pathogen transmission risk during transfusion. The validation of IBS, the trombocyte count for100 buffy coat concentrates from 2007 were compared to values for 100 buffy coat concentrates from 2006 that had been treated with gamma-radiation. Akademiska sjukhuset in Uppsala has a requirement that 75% of the platelet concentrates contain at least 300*10 9 platelets per unit. IBS fulfilled to 94% compared to 98% for the routine method.</p><p>Thus, the IBS-method was well above the required value and is now used at</p><p>Akademiska sjukhuset in Uppsala.</p>

Background. Platelets (thrombocytes) are the smallest cells in the blood. Platelet fulfils functions as formation of blood clots when bleeding. Low levels leads to bleeding while high levels increase the risk of thrombosis (obstruction of the circulatory flow system). Platelet transfusions may be required for patients with systemic bleeding and for patients at higher risk of bleeding because of coagulation defects, sepsis (presence of bacteria in the bloodstream), or platelet dysfunction related to medication or disease. A pathogen-reduction system for platelet components would be a useful method since it reduces the risk of bacterial, protozoa, viral and white blood cell contamination. The Intercept Blood System method (IBS) for platelets, destroys DNA and RNA and was validated against the routine method in order to reduce pathogen transmission risk during transfusion. The validation of IBS, the trombocyte count for100 buffy coat concentrates from 2007 were compared to values for 100 buffy coat concentrates from 2006 that had been treated with gamma-radiation. Akademiska sjukhuset in Uppsala has a requirement that 75% of the platelet concentrates contain at least 300*10 9 platelets per unit. IBS fulfilled to 94% compared to 98% for the routine method. Thus, the IBS-method was well above the required value and is now used at Akademiska sjukhuset in Uppsala.

As brássicas compreendem diversas espécies de grande relevância comercial dentre as demais espécies olerícolas cultivadas no Brasil. A região localizada próxima à cidade de São Paulo (SP) tem se destacado no cultivo de brássicas, especialmente do repolho, da couve-flor e do brócolis. Em campos de cultivo destas espécies, tem sido observadas plantas exibindo redução de tamanho, inflorescências mal formadas, avermelhamento de folhas e necrose dos vasos condutores. Investigações tem mostrado que estas anormalidades estão associadas aos fitoplasmas e a doença tem sido denominada enfezamento. Ainda, estudos anteriores têm sugerido a ocorrência de algumas espécies de cigarrinhas potencialmente vetoras destes fitoplasmas. Considerando estas informações, o presente trabalho teve por objetivo identificar espécies transmissoras de fitoplasmas para plantas de brócolis, buscando aumentar os conhecimentos sobre os vetores de fitoplasmas envolvidos com o enfezamento desta cultura. Para isto, foram coletados insetos no interior e áreas marginais de campos cultivados. Estes insetos foram separados em grupos, identificados taxonomicamente e confinados em plantas sadias de brócolis. A avaliação da transmissão foi feita com base na detecção de fitoplasmas nos tecidos dos insetos e das plantas, usando-se a técnica de PCR duplo, com primers específicos para identificação de fitoplasmas do grupo 16SrIII. A sobrevivência dos insetos nas plantas de brócolis foi pouco duradoura, não excedendo 48 horas. A transmissão experimental foi constatada em 30% das plantas inoculadas. Dentre as 8 potenciais espécies de vetores que foram testadas, as espécies Atanus nitidus, Balclutha hebe, Agalliana sticticollis e Agallia albidula transmitiram fitoplasma para plantas de brócolis. Os resultados deste estudo confirmaram aqueles obtidos nas investigações anteriores, as quais sugeriam a ocorrência de potenciais espécies vetoras de fitoplasmas dentre aquelas presentes nos campos de cultivo. No entanto, o conhecimento de detalhes sobre a transmissão necessita de estudos com populações sadias e infectivas das espécies vetoras, sob condições controladas. Apesar desta necessidade, uma etapa importante foi cumprida no presente trabalho, o qual se constitui numa contribuição relevante tanto para o conhecimento de aspectos epidemiológicos relacionados à disseminação do agente causal do enfezamento do brócolis como para a área de conhecimento relacionada à transmissão de patógenos por insetos vetores, nas condições brasileiras. / Cole crops include several species of commercial importance among the vegetable crops cultivated in Brazil. The region located near the city of São Paulo (SP) has excelled in the cultivation of brassica, especially cabbage, cauliflower and broccoli. In cultivated fields with these species have been observed plants showing reduction of size, malformed inflorescences, reddening of leaves and necrosis of region of vessels. Previous investigations have shown that these abnormalities are associated with phytoplasmas and the disease has been called stunt. In addition, previous studies have suggested the occurrence of some species of leafhoppers potentially vectors of phytoplasmas. Considering this information, the present study aimed to identify species that transmit phytoplasmas to plants of broccoli, seeking to increase knowledge about vectors of phytoplasmas involved with this culture. Thus, insects were collected within and in marginal areas of cultivated fields. These insects were separated into groups, taxonomically identified and confined in healthy plants of broccoli. The evaluation of transmission was based on detection of phytoplasmas in the tissues of plants and insects using the technique of nested PCR with specific primers for identification of phytoplasmas group 16SrIII. The survival of insects on plants of broccoli was short-lived, not exceeding 48 hours. The experimental transmission was observed in 30% of inoculated plants. Among the 8 potential vector species that were tested, the species Atanus nitidus, Balclutha hebe, Agalliana sticticollis and Agallia albidula transmitted phytoplasma to plants of broccoli. The results of the present study confirmed those obtained in previous research, which suggested the occurrence of potential vector species of phytoplasmas among those present in crop fields. However, details about these species as vectors require the creation of healthy populations of these species and infective for broadcast demonstration in controlled conditions. Despite this need, an important step has been accomplished in this work, which constitutes a significant contribution both to the knowledge of epidemiological aspects related to the spread of causal agent of broccoli stunt and the area of knowledge related to the transmission of pathogens by insects vectors, the Brazilian conditions.