Les polérovirus infectent une large gamme de plantes d’intérêt économique. Ils sont transmis par un insecte vecteur, le puceron, selon le mode circulant non-multipliant. Le virus, acquis par le puceron lors de l’ingestion de sève sur une plante infectée, traverse l’épithélium des cellules intestinales puis celui des glandes salivaires par un mécanisme de transcytose impliquant des récepteurs encore inconnus. Le récepteur de l’éphrine (Eph) est une protéine membranaire dont un domaine est capable de se lier dans la levure aux protéines structurales des polérovirus. En développant des techniques basées sur l’ARN interférence, nous avons montré que l’acquisition orale d’ARN double brin ciblant Eph chez le puceron Myzus persicae permet de réduire de manière reproductible l’internalisation des polérovirus dans le corps du puceron. Les pucerons ainsi traités transmettent le virus avec une efficacité réduite. Eph pourrait donc assurer la fonction de récepteur des polérovirus chez M. persicae. / Poleroviruses infect a wide range of economically important plants. They are transmitted in a circulative and non-propagative mode by an insect vector, the aphid. The virus particles are acquired by aphids when ingesting the sap from an infected plant and cross successively the epithelia of the midgut and the salivary gland cells by a transcytosis mechanism that relies on the presence of unknown receptors.The ephrin receptor (Eph) is a membrane protein which contains a domain able to bind in yeast to the structural proteins of poleroviruses. By developing methods based on RNA interference, we have shown that oral acquisition of double-stranded RNA targeting Eph in the aphid Myzus persicae can reproducibly reduce polerovirus internalization into the aphid's body. Such treated aphids transmit the virus to plants with a lower efficiency. Eph could therefore function as a receptor for poleroviruses in M. persicae.

Thesis (MScMedSc))--Stellenbosch University, 2012. / Includes bibliography / ENGLISH ABSTRACT: Despite the availability of Hepatitis B virus (HBV) vaccination for over three decades, this infection remains a major public health problem. Whilst the WHO recommends giving a birth dose of the vaccine, in South Africa, routine infant HBV vaccination commences at six weeks of age. This schedule is based on data from the pre-HIV era which showed transmission occurred via the horizontal, rather than the vertical route. In the era of HIV however, maternal HIV co-infection may release HBV from immune control, resulting in higher HBV loads and increasing the risk of vertical transmission. The aim of this study was to determine the prevalence and character of HBV infection in HIV-exposed infected and uninfected infants. Residual plasma samples from routine HIV nucleic acid testing of 1000 HIV-exposed infants aged between 0 and 18 months from the Western Cape were tested. Samples were tested for HBsAg by ELISA (Murex HBsAg Version 3) and confirmed by neutralisation. HBV DNA was quantified using an in-house real-time PCR assay. Infants with HBsAg positive samples were followed up and a blood sample was collected from mother and child. Those HBsAg positive samples were tested for HBeAg/antiHBe (Diasorin) and HBsAg negative samples were tested for antiHBs. HBV DNA was quantified. The surface gene was sequenced and the HBV genotype determined by phylogenetic analysis using HepSEQ (www.hepseq.org.uk). Whole genome sequencing was also performed. Of 1000 samples tested, four samples were positive for HBsAg and/or HBV DNA, indicating a prevalence of HBV transmission of 0.4%. At follow-up, two of three infected infants were positive for HBsAg, with HBV viral loads of greater than 108 IU/ml. The third infant was found to have cleared his infection and the fourth child was lost to follow up. These infected infants had all received HBV vaccination. All four mothers were HBeAg positive. Sequencing analysis showed the HBV strains from the two infants and four mothers belonged to subgenotype A1. The two mother-child paired sequences were identical. The data from this study shows that vertical transmission of HBV infection in HIV-exposed infants from the Western Cape is occurring, despite vaccination. Data from the Western Cape, showing an HBV prevalence of 3.4% in HIV-infected pregnant women, and those presented here suggest a vertical transmission rate of HBV of 12%. This is despite the widespread use of tenofovir and lamivudine in HIV-infected women with low CD4 counts. This study provides data supporting calls to bring HBV vaccination closer to the time of birth. Further work is urgently needed to confirm these findings and to determine the rates of transmission in HIV-unexposed infants. / AFRIKAANSE OPSOMMING: Ten spyte van die beskikbaarheid van die Hepatitis B virus (HBV) inenting vir meer as drie dekades, hierdie infeksie bly 'n groot openbare gesondheid probleem. Terwyl die WGO aan beveel dat'n geboorte dosis van die entstof, in Suid-Afrika, roetine baba HBV inenting op die ouderdom van ses weke gegee word. Hierdie skedule is gebaseer op data van die pre-MIV era wat getoon het dat die oordrag plaasgevind het via die horisontale, eerder as die vertikale roete. In die era van MIV egter, moeder MIV ko-infeksie kan HBV vrylaat van immuun beheer, wat lei in hoër HBV vlakke en die verhoging van die risiko van vertikale oordrag. Die doel van hierdie studie was om die voorkoms en karakter van die HBV infeksie in MIV-besmette en onbesmette babas te bepaal. Residuele plasma monsters van roetine-MIV-nukleïensuur toetse van 'n 1000 MIV-blootgestelde babas tussen die ouderdomme van 0 en 18 maande van die Wes-Kaap was getoets. Monsters was getoets vir HBsAg deur ELISA (Murex HBsAg Version 3) en bevestig deur neutralisering. HBV DNA is gekwantifiseer deur gebruik te maak van 'n in-huis real-time PCR assay. Babas met HBsAg positiewe monsters was opgevolg en 'n bloedmonster is versamel van moeder en kind. Die HBsAg positiewe monsters was getoets vir HBeAg/antiHBe (Diasorin) en HBsAg negatiewe monsters was getoets vir antiHBs. HBV DNA was gekwantifiseer. Die oppervlak gene volgorde en genotipes was bepaal deur filogenetiese analise met behulp van HepSEQ (www.hepseq.org.uk). Die hele genoom-volgordebepaling was ook uitgevoer. Van die 1000 monsters wat getoets was, was vier monsters positief vir HBsAg en of HBV DNA, dit dui op 'n voorkoms van HBV oordrag van 0.4%. By op volg, twee van die drie besmette babas was positief vir HBsAg, met HBV virale vlakke van groter as 108 IE/ml. Die derde baba was gevind dat sy infeksie opgeklaar het en die vierde kind was verlore as gevolg van op volg. Hierdie besmette babas het almal HBV inenting ontvang. Al vier moeders was HBeAg positief. Volgordebepaling analise het getoon die HBV stamme van die twee babas en vier moeders behoort aan subgenotype A1. Die twee moeder-kind gepaarde rye was homoloë. Die data van hierdie studie toon dat die vertikale oordrag van HBV infeksie in MIV-blootgestelde babas van die Wes-Kaap vind plaas, ten spyte van inenting. Data van die Wes-Kaap, wat 'n HBV voorkoms van 3.4% in MIV-besmette swanger vroue, en dié wat hier aangebied is dui op 'n vertikale oordrag koers van 12% van die HBV. Dit is ten spyte van die wydverspreide gebruik van tenofovir en lamivudine in MIV-geïnfekteerde vroue met 'n lae CD4-telling. Hierdie studie bied data wat ondersteunende oproepe van HBV inenting nader aan die tyd van die geboorte bring. Verdere werk is dringend nodig om die bevindinge te bevestig en die pryse van die oordrag in MIV-blootgestelde babas te bepaal. / National Health Laboratory Service Research Trust / Poliomyelitis Research Foundation (PRF) / Harry Crossley Foundation / Stellenbosch University

O Vírus Sincicial Respiratório (RSV) é reconhecido como agente causador de infecção nosocomial entre receptores de pacientes de células-tronco hematopoéticas causando morbidade e mortalidade consideráveis nesses pacientes. O objetivo desse estudo foi caracterizar as cepas do RSV isoladas de receptores de transplante de células-tronco hematopoéticas (TCTH) do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo durante sua estação. As cepas do RSV foram tipadas (em grupo A ou B) e genotipadas. Das sete cepas analisadas dos receptores de TCTH durante o ano de 2001, somente duas pertenciam ao grupo B, as outras cinco eram pertencentes ao grupo A. Dessas sete cepas, três eram altamente relacionadas e haviam infectados pacientes que freqüentavam o ambulatório. Em 2002, das doze cepas analisadas, três pertenciam ao grupo A e as outras nove pertenciam ao grupo B. Sete cepas eram altamente relacionadas entre elas e eram também de pacientes de ambulatório sugerindo que a transmissão em hospital-dia era mais provável. Enfim, múltiplços genótipos do RSV co-circularam nas unidades de TCTH (ambulatório e enfermaria) do Hospital das Clínicas entre 2001 e 2002. A transmissão nosocomial foi mais provável ocorrer no ambulatório da unidade de TCTH quando comparada à enfermaria. Políticas de controle de infecção devem ser também implementadas em ambulatórios para evitar transmissão nosocomial do RSV e outros vírus respiratórios em pacientes de ambulatório. / Respiratory Syncytial Virus is recognized as the leading cause of nosocomial respiratory infection among recipients of hematopoietic stem cell transplant (HSCT) causing considerable morbity and mortality among theses patients. The aim this study was characterize the strains of Respiratory Syncytial Virus in recipients Hematopoietic Stem Cell Transplant Unit (HSCT) at Hospital das Clínicas, University of São Paulo Medical School during RSV season in symptomatic HSCT recipients at Hospital das Clínicas. The strains of RSV was typed (in group A or B) and genotyped. Of the seven strains analyzed from HSCT recipients during 2001, only two belonged to group B, the other five belonged to group A. Of these seven strains, three were closely related and were from outpatients. In 2002 , of the twelve strains analyzed, three belonged to group A and the other nine belonged to group B. Seven strains were closely related and were also from outpatients suggesting that nosocomial transmission in hospital-day was more likely. In conclusion, multiples genotypes of RSV co-circulated in the Hematopoietic Stem Cell Transplant units (ward and dayhospital) of Hospital das Clínicas between 2001 and 2002. Nosocomial transmission was more likely to occur at the HSCT Day-hospital as compared to the HSCT ward. Infection control practices should be also implemented at Day-hospital Units to avoid nosocomial transmission of RSV and other respiratory viruses in outpatient units.

O Vírus Sincicial Respiratório (RSV) é reconhecido como agente causador de infecção nosocomial entre receptores de pacientes de células-tronco hematopoéticas causando morbidade e mortalidade consideráveis nesses pacientes. O objetivo desse estudo foi caracterizar as cepas do RSV isoladas de receptores de transplante de células-tronco hematopoéticas (TCTH) do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo durante sua estação. As cepas do RSV foram tipadas (em grupo A ou B) e genotipadas. Das sete cepas analisadas dos receptores de TCTH durante o ano de 2001, somente duas pertenciam ao grupo B, as outras cinco eram pertencentes ao grupo A. Dessas sete cepas, três eram altamente relacionadas e haviam infectados pacientes que freqüentavam o ambulatório. Em 2002, das doze cepas analisadas, três pertenciam ao grupo A e as outras nove pertenciam ao grupo B. Sete cepas eram altamente relacionadas entre elas e eram também de pacientes de ambulatório sugerindo que a transmissão em hospital-dia era mais provável. Enfim, múltiplços genótipos do RSV co-circularam nas unidades de TCTH (ambulatório e enfermaria) do Hospital das Clínicas entre 2001 e 2002. A transmissão nosocomial foi mais provável ocorrer no ambulatório da unidade de TCTH quando comparada à enfermaria. Políticas de controle de infecção devem ser também implementadas em ambulatórios para evitar transmissão nosocomial do RSV e outros vírus respiratórios em pacientes de ambulatório. / Respiratory Syncytial Virus is recognized as the leading cause of nosocomial respiratory infection among recipients of hematopoietic stem cell transplant (HSCT) causing considerable morbity and mortality among theses patients. The aim this study was characterize the strains of Respiratory Syncytial Virus in recipients Hematopoietic Stem Cell Transplant Unit (HSCT) at Hospital das Clínicas, University of São Paulo Medical School during RSV season in symptomatic HSCT recipients at Hospital das Clínicas. The strains of RSV was typed (in group A or B) and genotyped. Of the seven strains analyzed from HSCT recipients during 2001, only two belonged to group B, the other five belonged to group A. Of these seven strains, three were closely related and were from outpatients. In 2002 , of the twelve strains analyzed, three belonged to group A and the other nine belonged to group B. Seven strains were closely related and were also from outpatients suggesting that nosocomial transmission in hospital-day was more likely. In conclusion, multiples genotypes of RSV co-circulated in the Hematopoietic Stem Cell Transplant units (ward and dayhospital) of Hospital das Clínicas between 2001 and 2002. Nosocomial transmission was more likely to occur at the HSCT Day-hospital as compared to the HSCT ward. Infection control practices should be also implemented at Day-hospital Units to avoid nosocomial transmission of RSV and other respiratory viruses in outpatient units.

La maladie pied-main-bouche (PMB) et l’herpangine sont deux maladies pédiatriques bénignes causées par les entérovirus (EV), en particulier les sérotypes de l’espèce A (EV-A). Le sérotype EV-A71 fait l’objet d’une surveillance dans les pays du Sud Est de l’Asie car il est associé à des atteintes neurologiques sévères chez les très jeunes enfants, parfois mortelles (défaillance cardio-pulmonaire). Les infections causées par les autres EV-A tel que le coxsackievirus A16 (CV-A16) provoquent rarement des atteintes sévères. En Europe, les cas de maladie PMB causés par l’EV-A71 ne font pas l’objet d’une déclaration obligatoire, car ce virus ne cause pas d’épidémies de grande ampleur. L’objectif général de la thèse était d’étudier l’épidémiologie des EV-A en Europe et nous avons utilisé une approche phylogénétique bayésienne pour analyser un échantillon de 500 souches. Nous montrons la circulation discontinue de l’EV-A71 de deux populations virales principales (sous génogroupes C1 et C2), ce qui explique la rareté des épidémies en Europe. L’épidémiologie de ce virus est aussi caractérisée par des transports de souches entre les pays Européens et sporadiquement entre l’Europe et l’Asie (sous génogroupes B5 et C4). La recombinaison génétique intertypique survient rarement parmi les populations d’EV-A71 en circulation et ne contribue pas significativement à leur diversité génétique. Cependant, ce mécanisme génétique est relié à l’émergence d’un sous génogroupe CV-A16 qui circule en France depuis 2011. Comparés à l’EV-A71, les sérotypes CV-A2, CV-A4, CV-A6 sont plus fréquemment sujets à des événements de recombinaison intertypiques. L’analyse de la sélection à l’échelle moléculaire indique que la fixation des mutations dans les protéines de capside de l’EV-A71 est lente, probablement à cause des contraintes structurales et fonctionnelles. La surveillance des infections à EV-A71 en Europe devrait être renforcée à cause de la neurovirulence de ce virus, de l’introduction récente et répétée de souches variantes « asiatiques » et de l’existence d’une grande diversité de génogroupes en Afrique et en Inde encore peu explorée. / Hand-Foot and Mouth Disease (HFMD) and Herpangina are two benign pediatric diseases caused by Enteroviruses (EV), especially enterovirus A species serotypes (EV-A). Infections caused by the EV-A71 serotype are monitored in countries of South East Asia because they are associated with severe neurological symptoms in young children and may be fatal (cardiopulmonary failure). Infections caused by the other EV-A serotypes, e.g. coxsackievirus A16 (CV-A16), rarely induce severe symptoms. In Europe, EV-A71 HFMD cases are not notifiable because this virus does not cause large-scale epidemics. The overall objective of this thesis was to study the EV-A epidemiology in Europe and we used a Bayesian phylogenetic approach to analyze 500 viral strains. We show a discontinued circulation of two EV-A71 populations (C1 and C2 subgenogroups), which explains the rare outbreaks in Europe. The epidemiology of this virus is characterized by transportation events of viral strains between European countries and sporadically between Europe and Asia (C4 and B5 subgenogroups). Intertypic genetic recombination occur rarely among circulating EV-A71 populations and does not contribute significantly to their genetic diversity. We found that genetic mechanism was related to the emergence of a new CV-A16 subgenogroup, which is circulating in France since 2011. In comparison with EV-A71, a number of serotypes (CV-A2, CV-A4, and CV-A6) are more frequently involved in intertypic recombination events. The structural and functional constraints are possible factors involved in the slow mutation fixation in the EV-A71 capsid proteins as determined by analyses of molecular selection. Neurovirulence, the recent and repeated introductions of variants “Asian” strains, and the diversity of genogroups in Africa and India call for strengthened surveillance of EV-A71 infections among European countries.

The aim of this study was to assess the extent on how effective was the prevention of mother-to-child transmission of Human Immunodeficiency Virus (HIV) infection at Oshakati District Health Centre. Explanatory survey was used to conduct the research. A total of 160 nurses experienced in prevention of mother-to-child transmission and women who attended antenatal care and post natal care services participated in the study. Respondents expressed unsatisfactory with the promoting involvement of male partners, high quality voluntary counselling and testing services, couple counselling and testing, integration of Highly Active Antiretroviral Therapy services, administration of short course of Zidovudine to pregnant mothers and the provision of antiretroviral drugs to infants. Therefore, promoting involvement of male partners, couple counselling and testing, administration of short course of Zidovudine to pregnant mothers and educating women about exclusive breastfeeding prior to delivery are some of recommendations for effective prevention of mother-to-child transmission of HIV infections. / Health Studies / (M.A. (Public Health))

Thesis (MScMedSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Hepatitis B virus (HBV) immunisation protocols in much of Africa are based on data from the pre-human immunodeficiency virus (pre-HIV) era that indicated that HBV transmission occurs predominantly horizontally between siblings and play-mates rather than vertically from mother to child. The immunosuppression associated with HIV infection however may release HBV from immune control resulting in higher HBV viral loads, which may increase the risk of perinatal mother to child transmission of HBV. The aim of this study was to determine the prevalence and characteristics of chronic HBV infection in HIV-infected pregnant women compared to HIV-uninfected pregnant women in the Western Cape province of South Africa. Ethical approval was obtained to conduct a retrospective, matched case-control, unlinked anonymous study using residual plasma samples from the 9355 pregnant women included in the Western Cape's 2008 National HIV and Syphilis Antenatal Survey. Samples were tested for HBsAg on the AxSYM (Abbott, Chicago, IL) and confirmed by neutralization. Confirmed HBsAg-positive samples were tested for HBeAg, anti-HBe and anti-HD (Diasorin, Saluggia, Italy) and had HBV viral load and genotyping done. In addition, HBsAg-negative samples were tested for anti-HBc. Samples from 1549 HIV-infected pregnant women were included and matched to the same number of samples from age- and race-matched HIV-uninfected women. Median age of 26 years, parity and education were similar in the two groups. The prevalence of HBsAg was 3.4% for the HIV-infected group and 2.9% for the HIV-uninfected group. HBV DNA loads of greater than 104 IU/ml were detected in 32.1% of HBsAg-positive, HIV/HBV co-infected women, and in 14.3% HBsAg positive, HBV mono-infected women. Among the HIV-infected group 18.9% of HBsAg-positive were HBeAg positive, with a median viral load of 7.93 log10 IU/ml; whilst 15.5% HIV-uninfected women were positive for HBeAg with a median viral load of 6.07 log10 IU/ml. Genotype A was seen in 92.6% of the isolates while 7.4% of the isolates were genotype D. Serum total anti-HBc antibodies that are a marker of past infection were detected in 42.2% of HIV-infected and in 24.1% of HIV-uninfected women that were negative for HBsAg. No positive sample for anti-HD was seen among all HBsAg-positive samples. This data indicates that there is increased exposure to HBV in HIV-infected pregnant women than in HIV-uninfected women and that a greater proportion of HIV-infected pregnant women compared to HBV mono-infected pregnant women may be at increased risk of transmitting HBV to their infants. Further studies are needed to determine the rate of vertical transmission of HBV in the HIV era. / AFRIKAANSE OPSOMMING: Hepatitis B virus (HBV) immunisasie protokolle vir meeste dele van Afrika is gebaseer op data versamel in die era voor MIV. Die data dui aan dat HBV oordrag hoofsaaklik deur horisontale transmissie tussen broers, susters en speelmaats eerder as vertikale transmissie van moeder na kind plaasvind. Die onderdrukking van die immuunstelsel as gevolg van MIV infeksie kan egter lei tot 'n verhoogde risiko van perinatale HBV oordrag van moeder na kind. Die doel van hierdie studie was om die voorkoms en karakter van chroniese HBV infeksie in MIV-positiewe swanger vroue te vergelyk met die van MIV-negatiewe swanger vroue. Etiese goedkeuring is verkry om 'n retrospektiewe, deursnee-, ongekoppelde anonieme studie uit te voer wat gebruik maak van oorblywende plasma monsters van 9355 swanger vroue wat ingesluit is in die Wes-Kaap 2008 Nasionale MIV en Sifilis Voorgeboortelike Opname. Die monsters was getoets vir HBsAg antiliggame (AxSYM, Abbott, Chicago, IL) en bevestig deur neutralisasie toetse. Positiewe monsters was getoets vir HBeAg en anti-HBe (Diasorin, Saluggia, Italië). HBV viruslading en genotipering was ook op HBsAg positiewe monsters gedoen. Die HBsAg negatiewe monsters was getoets vir die teenwoordigheid van anti-HBc. Monsters van 1549 MIV-positiewe swanger vroue was ingesluit in die studie. Dieselfde aantal monsters van MIV-negatiewe vroue, met ooreenstemende ouderdom en etnisiteit, was ingesluit as kontroles. Die gemiddelde ouderdom van albei groepe was 26 jaar. Pariteit en opvoeding was dieselfde in albei groepe. Die voorkomssyfer van HbsAg was 3.4% in die MIV-positiewe groep en 2.8% in die MIV-negatiewe groep. HBV DNS ladings van meer as 104 IU/ml was waargeneem in 32.1% van die MIV-mede-geinfekteerde vroue en in 14.3% van die MIV-negatiewe groep. In die MIV-positiewe groep was 18.9% vroue HBeAg positief, met 'n gemiddelde virale lading van 7.93 log10 IU/ml, terwyl 15.5% MIV-negatiewe vroue positief was vir HBeAg met 'n gemiddelde virale lading van 6.07 log10 IU/ml. In ons studie was 92.6% van die monsters genotipe A en 7.4% genotipe D. Toatale anti-HBc antiliggame, 'n merker van vorige infeksie, was gevind in 42.2% van MIV-mede-geïnfekteerde vroue en 24.1% van MIV-negatiewe vroue wat negatief was vir HBsAg antiliggame. Data van ons studie dui op 'n verhoogde risiko vir vertikale HBV transmissie van MIV-positiewe moeders na hul babas. Verdere studies word benodig om vas te stel of vertikale transmissie van HBV van MIV-positiewe vroue na hul babas plaasvind. / Wellcome Trust / Poliomyelitis Research Foundation

The aim of this study was to assess the extent on how effective was the prevention of mother-to-child transmission of Human Immunodeficiency Virus (HIV) infection at Oshakati District Health Centre. Explanatory survey was used to conduct the research. A total of 160 nurses experienced in prevention of mother-to-child transmission and women who attended antenatal care and post natal care services participated in the study. Respondents expressed unsatisfactory with the promoting involvement of male partners, high quality voluntary counselling and testing services, couple counselling and testing, integration of Highly Active Antiretroviral Therapy services, administration of short course of Zidovudine to pregnant mothers and the provision of antiretroviral drugs to infants. Therefore, promoting involvement of male partners, couple counselling and testing, administration of short course of Zidovudine to pregnant mothers and educating women about exclusive breastfeeding prior to delivery are some of recommendations for effective prevention of mother-to-child transmission of HIV infections. / Health Studies / M.A. (Public Health)

La dengue circule en Polynésie française sur un mode épidémique depuis plus de 35 ans. Néanmoins, en dépit de la taille relativement faible de la population de Polynésie française, la circulation de la dengue peut persister à de faibles niveaux pendant de nombreuses années. L’objectif de ce travail de thèse est de déterminer si l'épidémiologie de la dengue dans le système insulaire de la Polynésie française répond aux critères d’un contexte de métapopulation. Après avoir constitué une base de données regroupant les cas de dengue répertoriés sur les 35 dernières années, nous avons réalisé des analyses épidémiologiques descriptives et statistiques. Celles-ci ont révélé des disparités spatio-temporelles distinctes pour l’incidence de la dengue des archipels et des îles, mais la structure de l'épidémie globale à l’échelle de la Polynésie française pour un même sérotype ne semble pas être affectée. Les analyses de la métapopulation ont révélé l'incidence asynchrone de la dengue dans un grand nombre d’îles. Celle-ci s’observe plus particulièrement par la différence de dynamique de l’incidence entre les îles plus peuplées et celles ayant une population plus faible. La taille critique de la communauté nécessaire à la persistance de la dengue n’est même pas atteinte par la plus grande île de Polynésie Française, Tahiti. Ce résultat suggère que la dengue peut uniquement persister grâce à sa propagation d’île en île. L'incorporation de la connectivité des îles à travers des modèles de migration humaine dans un modèle mathématique a produit une dynamique de la dengue davantage en adéquation avec les données observées, que les tentatives de modélisation traitant la population dans son ensemble. Le modèle de la métapopulation a été capable de simuler la même dynamique que les cas de dengue observés pour l'épidémie et la transmission endémique qui a suivi pour la période de 2001 à 2008. Des analyses complémentaires sur la différenciation de l'incidence de la maladie et de l'infection seront probablement instructives pour affiner le modèle de métapopulation de l'épidémiologie de la dengue en Polynésie française. / Dengue has been epidemic in French Polynesia for the past 35 years. Despite the relatively small population size in French Polynesia, dengue does not disappear and can persist at low levels for many years. In light of the large number of islands comprising French Polynesia, this thesis addresses the extent to which a metapopulation context may be the most appropriate to describe the epidemiology and persistence of dengue in this case. After compiling a database of dengue cases over the last 35 years, we used a number of descriptive and statistical epidemiological analyses that revealed distinct spatio-temporal disparity in dengue incidence for archipelago and islands. But the global structure of the epidemics of the same serotype were not affected. Metapopulation analyses revealed asynchronous dengue incidence among many of the islands and most notably larger islands lagged behind the smaller islands. The critical community size, which determines dengue persistence, was found to exceed even the largest island of Tahiti, suggesting that dengue can only exist by island-hopping. Incorporation of island connectedness through patterns of human migration into a mathematical model enabled a much better fit to the observed data than treating the population as a whole. The metapopulation model was able to capture to some extent the epidemic and low level transmission dynamics observed for the period of 2001-2008. Further analyses on differentiating incidence of disease and infection will likely prove informative for the metapopulation model of dengue epidemiology in French Polynesia.