HIV-1 Transmission During Recent Infection and During Treatment Interruptions as Major Drivers of New Infections in the Swiss HIV Cohort Study.

BACKGROUND: Reducing the fraction of transmissions during recent human immunodeficiency virus (HIV) infection is essential for the population-level success of "treatment as prevention". METHODS: A phylogenetic tree was constructed with 19 604 Swiss sequences and 90 994 non-Swiss background sequences. Swiss transmission pairs were identified using 104 combinations of genetic distance (1%-2.5%) and bootstrap (50%-100%) thresholds, to examine the effect of those criteria. Monophyletic pairs were classified as recent or chronic transmission based on the time interval between estimated seroconversion dates. Logistic regression with adjustment for clinical and demographic characteristics was used to identify risk factors associated with transmission during recent or chronic infection. FINDINGS: Seroconversion dates were estimated for 4079 patients on the phylogeny, and comprised between 71 (distance, 1%; bootstrap, 100%) to 378 transmission pairs (distance, 2.5%; bootstrap, 50%). We found that 43.7% (range, 41%-56%) of the transmissions occurred during the first year of infection. Stricter phylogenetic definition of transmission pairs was associated with higher recent-phase transmission fraction. Chronic-phase viral load area under the curve (adjusted odds ratio, 3; 95% confidence interval, 1.64-5.48) and time to antiretroviral therapy (ART) start (adjusted odds ratio 1.4/y; 1.11-1.77) were associated with chronic-phase transmission as opposed to recent transmission. Importantly, at least 14% of the chronic-phase transmission events occurred after the transmitter had interrupted ART. CONCLUSIONS: We demonstrate a high fraction of transmission during recent HIV infection but also chronic transmissions after interruption of ART in Switzerland. Both represent key issues for treatment as prevention and underline the importance of early diagnosis and of early and continuous treatment.

A retrospective study of deep sternal wound infections: clinical and microbiological characteristics, treatment, and risk factors for complications.

Deep sternal wound infection (DSWI) is a feared complication following cardiac surgery. This study describes clinical, microbiological, and treatment outcomes of DSWI and determines risk factors for complications. Of 55 patients with DSWI, 66% were male and mean age was 68.2years. Initial sternotomy was for coronary artery bypass graft in 49% of patients. Sternal debridement at mean 25.4±18.3days showed monomicrobial (94%), mainly Gram-positive infection. Secondary sternal wound infection (SSWI) occurred in 31% of patients, was mostly polymicrobial (71%), and was predominantly due to Gram-negative bacilli. Risk factors for SSWI were at least 1 revision surgery (odds ratio [OR] 4.8 [95% confidence interval {CI} 1.0-22.4], P=0.047), sternal closure by muscle flap (OR 4.6 [1.3-16.8], P=0.02), delayed sternal closure (mean 27 versus 14days, P=0.03), and use of vacuum-assisted closure device (100% versus 58%, P=0.008). Hospital stay was significantly longer in patients with SSWI (69days versus 48days, P=0.04).

Maladie des griffes du chat et autres bartonelloses [Cat scratch disease and other human infections caused by Bartonella species].

The different Bartonella species can cause various human infections such as cat scratch disease, chronic bacteremia (homeless patient with nonspecific symptom), endocarditis, bacillary angiomatosis, peliosis, and Carrion's disease. Diagnostic approaches include serology, culture and molecular approaches. PCR is especially useful on lymph nodes biopsies from patients with cat-scratch disease and on valvular samples taken from culture-negative endocarditis. Serology exhibits a very high sensitivity in the latter situation. The treatment should be chosen according to the clinical presentation.

Is Switzerland doing enough regarding the prevention of syphilis, gonorrhea and chlamydia infections ?

Sexually transmitted infections are a major problem for medicine and for public health services worldwide. More than 30 sexually transmittable pathogenic micro-organisms are known, including bacteria, viruses, fungi, protozoa and ectoparasites. According to estimates from the World Health Organisation more than 333 million of bacterial sexually transmitted infections occur worldwide per year. Sexually transmitted infections, by their nature, affect individuals, within partnerships and larger sexual networks, and in turn populations. This report focuses on three bacterial sexually transmitted infections in Switzerland that are Chlamydia trachomatis, Neisseria gonorrhea and Treponema pallidum (syphilis) in Switzerland. The prevalence of these infections has been increasing alarmingly for a decade. All three infections can be asymptomatic and their diagnosis and treatment can therefore occur too late or worse not at all, even though treatments are available. This is an important problem as untreated sexually transmitted infections may cause complications such as ascending infections, infertility, ectopic pregnancies and serious long-term neurological sequels. The consequences of these infections should not be underestimated. They constitute a significant public health burden as well as serious financial burden. The increases in chlamydia, syphilis and gonorrhea infections have also been observed in many European countries. Countries, where rising numbers of sexually transmitted infections have been observed, have reacted in different ways. Some have developed clinical guidelines or implemented screening programs, while others are still in their observational phase. The aim of this mémoire is to assess whether Switzerland is doing enough regarding the prevention of chlamydial, syphilis and gonorrheal infections. After first describing the infections, surveillance systems of sexually transmitted infections are assessed, then the epidemiological trends of these three infections are described, and finally the prevention measures implemented in Switzerland to respond to the increasing number of infections are described. The reaction of the United Kingdom to the same problem is reported for comparison. [Author, p. 7]

Predator or prey? Chlamydophila abortus infections of a free-living amoebae, Acanthamoeba castellani 9GU.

Limited evidence exists to suggest that the ability to invade and escape protozoan host cell bactericidal activity extends to members of the Chlamydiaceae, intracellular pathogens of humans and animals and evolutionary descendants of amoeba-resisting Chlamydia-like organisms. PCR and microscopic analyses of Chlamydophila abortus infections of Acanthamoeba castellani revealed uptake of this chlamydial pathogen but, unlike the well-described inhabitant of A. castellani, Parachlamydia acanthamoebae, Cp. abortus did not appear to propagate and is likely digested by its amoebal host. These data raise doubts about the ability of free-living amoebae to serve as hosts and vectors of pathogenic members of the Chlamydiaceae but reveal opportunities, via comparative genomics, to understand virulence mechanisms used by Chlamydia-like organisms to avoid amoebal digestion.

Virus Infections in Early Childhood, Cow’s Milk Formula Exposure and Genetic Predisposition in the Development of Diabetes-Associated Autoimmunity

Varhaislapsuuden virusinfektioiden, lehmänmaitopohjaisen äidinmaitovastikeen ja geneettisen alttiuden merkitys diabetekseen liittyvän autoimmuniteetin kehittymisessä Tyypin 1 diabetes on autoimmuunisairaus, joka syntyy haiman insuliinia tuottavien beta-solujen tuhouduttua elimistön oman immuunipuolustusjärjestelmän hyökkäyksen seurauksena. Sekä perimän että ympäristötekijöiden arvellaan vaikuttavan tautiprosessiin, mutta taudin tarkkaa syntymekanismia ei tunneta. Tutkimuksen tarkoituksena oli selvittää varhaislapsuuden ympäristötekijöiden vaikutusta beta-soluautoimmuniteetin syntyyn, erityispaino tutkimuksessa oli ympäristötekijöiden yhteisvaikutuksessa sekä geneettisten riskitekijöiden ja ympäristötekijöiden vuorovaikutuksessa. Varhaislapsuudessa sairastettu sytomegalovirus- tai enterovirusinfektio ei lisännyt beta-soluautoimmuniteetin riskiä lapsilla, joilla on geneettisesti kohonnut riski sairastua tyypin 1 diabetekseen. Ennen puolen vuoden ikää sairastettu rotavirusinfektio lisäsi hieman tyypin 1 diabetekseen liittyvän autoimmuniteetin riskiä. Tarkemmassa analyysissa varhaislapsuuden enterovirusinfektio osoittautui kuitenkin autovasta-aineiden muodostumisen riskitekijäksi niiden lasten joukossa, jotka olivat saaneet lehmänmaitopohjaista äidinmaidon vastiketta ensimmäisten elinkuukausien aikana. Tämä löydös viittaa enterovirusinfektion ja lehmänmaitopohjaisen vastikkeen yhteisvaikutukseen tyypin 1 diabetekseen liittyvän autoimmuniteetin synnyssä. Löydösten mukaan PTPN22 geenin C1858T polymorfismi vaikuttaa CD4+ T solujen aktivaatioon ja proliferaatiovasteeseen, 1858T alleeliin liittyy alentunut T-soluresepto-rivälitteinen aktivaatio. 1858T alleelin kantajuuteen liittyy lisäksi lisääntynyt autovasta-aineiden ja kliinisen diabeteksen ilmaantuvuus. Tämä yhteys rajoittui yksilöihin, jotka olivat altistuneet lehmänmaitopohjaiselle vastikkeelle ennen kuuden kuukauden ikää. Tulosten mukaan sekä ympäristötekijöiden väliset yhteisvaikutukset että perimä vaikuttavat yksittäisen ympäristötekijän merkitykseen tyypin 1 diabetekseen liittyvän autoimmuniteetin synnyssä. Nämä yhteisvaikutukset ympäristötekijöiden kesken ja perimän ja ympäristötekijöiden välillä selittävät aiemmin julkaistujen tulosten ristiriittaisuutta tutkimuksissa, joissa on analysoitu vain yhden ympäristötekijän vaikutusta diabeteksen ilmaantuvuuteen.

Fronts with continuous waiting-time distributions: Theory and application to virus infections

We generalize to arbitrary waiting-time distributions some results which were previously derived for discrete distributions. We show that for any two waiting-time distributions with the same mean delay time, that with higher dispersion will lead to a faster front. Experimental data on the speed of virus infections in a plaque are correctly explained by the theoretical predictions using a Gaussian delay-time distribution, which is more realistic for this system than the Dirac delta distribution considered previously [J. Fort and V. Méndez, Phys. Rev. Lett.89, 178101 (2002)]

Effects of single and double infections with Potato virus X and Tobacco mosaic virus on disease development, plant growth, and virus accumulation in tomato

The tomato cv. Fukuju nº. 2 was used for studying the effect of single and double infections with Potato virus X (PVX) and Tobacco mosaic virus (TMV). Mixed infection resulted in a synergistic increase of disease severity, where more growth reduction was seen with simultaneous inoculations than with sequential inoculations at four-day intervals. At five and 12 days post-inoculation, the increased severity of the disease coincided with enhancement of virus accumulation in the rapidly expanding upper leaves. The PVX concentration in leaves nº 5 to 7 of doubly infected plants was three to six fold that of singly infected ones, as determined by DAS-ELISA. Mixed infection with the L strain led to higher enhancement of PVX than with the TMV-L11A strain. The concentration of TMV-L was lower in double infection and significantly higher than TMV-L11A in both singly and doubly infected plants. Analyses of the PVX ORF2 by Western blot and Northern hybridization revealed the pattern of accumulation of the 25 kDa protein and the RNAs, respectively, following those of the virion and coat protein. The strain TMV-L11A overcame the resistance gene in cv. GCR 237 (Tm-1). In the upper leaf nº. 8, the concentration of PVX was three times higher in plants with mixed infection than with L11A. The concentrations of the L and OM (TMV strains) in both singly and doubly infected plants were at very low levels, and the synergistic effect on PVX concentration and disease severity was not observed.

The Role of Integrins in Enterovirus Infections and in Metastasis of Cancer

Integrins are a family of transmembrane glycoproteins, composed of two different subunits (alpha and beta). Altered expression of integrins in tumor cells contributes to metastasis tendency by influencing on the cells‟ attachment to adjacent cells and their migration. Viral pathogens, including certain enteroviruses, use integrins as receptors. Enteroviruses have also been suggested to be involved in the etiopathogenesis of type 1 diabetes. The study focuses on the role of integrins in the pathogenesis of metastasis to cortical bone and on type 1 diabetes (T1D) and echovirus 1 infection. In the first part of the thesis, the role of different integrins in the initial attachment of MDA-MD-231 breast cancer cells to bovine cortical bone disks was studied. A close correlation between alpha2beta1 and alpha3beta1 integrin receptor expression and the capability of the tumor to attach to bone were observed. In the second part, a possible correlation between susceptibility to enterovirus infections in diabetic children and differences in enterovirus receptor genes, including certain integrins, was investigated. In parallel, virus-specific neutralizing antibodies and diabetic risk alleles were studied. In the diabetic group, an amino acid change was detected in the polio virus receptor and the neutralizing antibody titers against echovirus 30 were lower. However, to obtain statistically sustainable results, a larger number of individuals should be analyzed. Echovirus 1 (EV1) enters cells by attaching to the alpha2I domain of the alpha2beta1 integrin. In the third part EV1 was shown to attach to a chimeric receptor construct of the transferrin receptor and the alpha2I domain and to enter cells through clathrin-mediated endocytosis that is normally not used by the virus. The chimeric receptor was recycled to the plasma membrane, whereas the virus remained in intracellular vesicles. The virus replication cycle was initiated in these cells, suggesting that evolution pressure could possibly cause the virus to evolve to use a different entry mechanism. Moreover, a cDNA microarray analysis of host gene expression during EV1 replication showed that 0.53% of the total genes, including several immediate early genes, were differently expressed.

Outcomes of cervical human papillomavirus (HPV) infections among mothers in the Finnish Family HPV Study

To understand the natural history of cervical human papillomavirus (HPV)-infections, more information is needed on their genotype-specific prevalence, acquisition, clearance, persistence and progression. This thesis is part of the prospective Finnish Family HPV study. 329 pregnant women (mean age 25.5 years) were recruited during the third trimester of pregnancy and were followed up for 6 years. The outcomes of cervical HPV infections were evaluated among all the mothers participating in the study. Generalized estimating equation (GEE)-models and Poisson regression were used to estimate the risk factors of type-specific acquisition, clearance, persistence and progression of Species 7 and 9 HPV-genotypes. Independent protective factors against incident infections were higher number of life-time sexual partners, initiation of oral contraceptive use after age 20 years and becoming pregnant during FU. Older age and negative oral HR-HPV DNA status at baseline were associated with increased clearance, whereas higher number of current sexual partners decreased the probability of clearance. Early onset of smoking, practicing oral sex and older age increased the risk of type-specific persistence, while key predictors of CIN/SIL were persistent HR-HPV, abnormal Pap smear and new sexual partners. HPV16, together with multiple-type infections were the most frequent incident genotypes, most likely to remain persistent and least likely to clear. Collectively, LR-HPV types showed shorter incidence and clearance times than HR-HPV types. In multivariate models, different predictors were associated with these main viral outcomes, and there is some tentative evidence to suggest that oral mucosa might play a role in controlling some of these outcomes.

Histopathological features of infections caused by Fusarium oxysporum and F. solani in purple passionfruit plants (Passiflora edulis Sims)

The purple passionfruit plant, Passifloraedulis Sims, ranks second in fruit exportation in Colombia, and its main destination is the European market. However, its production is affected by several diseases, including fusariosis. This paper presents the histopathological features of different tissues affected by the pathogens Fusarium oxysporum and Fusarium solani. Both microorganisms produce similar responses on the plant: colonization of xylem vessels by hyphae and microconidia, hypertrophy and hyperplasia of the cambium, xylem and phloem; destruction of xylem fibers and amyloplasts in parenchymatous cells; and production of gels by the plant. However, there are differences in the colonization mechanism, F. solani penetrates and is concentrated especially at the collar zone, while F. oxysporum penetrates the roots and moves through the vascular system to colonize the plant.

Pikornavirusten käyttö geenivektoreina ja syöpäterapiassa sekä Coxsackievirus A7 -isolaattien sekvenssianalyysi

Kirjallisessa osassa tarkasteltiin pikornavirusten käyttöä geenivektoreina ja syöpäterapiassa. Pikornavirukset ovat positiivissäikeisiä RNA-viruksia, ja niiden genomi koostuu rakenteellisista kuoriproteiineista VP1-VP4 sekä ei-rakenteellisista proteiineista 2A-2C ja 3A-3D. Geenivektoritutkimukset ovat keskittyneet erilaisten inserttien kloonaamiseen virusten VP1-VP4-alueelle ja genomin 5'-päähän sekä näiden muutosten vaikutusten seuraamiseen virusten elinkierrossa solu- ja hiirimalleissa. Geenivektoreina on parhaiten toimineet coxsackievirukset B3, B4 ja A9 sekä mengo- ja poliovirus. Niitä on käytetty hiirissä mm. neuronien motorisen BDNF-reseptorin ilmentämiseen sekä hiiren interleukiini-10:n tuottamiseen selkäydinkanavan vaurioiden korjaamiseksi. Syöpäterapiatutkimuksissa on saatu lupaavia tuloksia coxsackieviruksilla A21, A13, A15 ja A18 sekä echo-, Seneca Valley 001- ja EMCV-viruksilla. Viruksilla on saatu mm. rintasyövän pääkasvain ja metastasoituneet etäpesäkkeet häviämään sekä eturauhassyövän kasvaimia pienenemään. Seneca Valley 001 -virus on osoittautunut tehokkaaksi syöpiä vastaan, joilla on neuroendokriinisiä ominaisuuksia. Viruksen käyttämistä faasi 2:n kliinisiin kokeisiin ollaan parhaillaan suunnittelemassa pienisoluisen keuhkosyövän ja lasten neuroendokriinisen syövän kohdalla. Kokeellisessa osassa optimoitiin RT-PCR-menetelmä coxsackievirus A7:n (CV-A7) genomin tuottamiseksi PCR-reaktiolla (FL-PCR). FL-PCR:n optimointi tehtiin vektoreilla, joihin oli kloonattu CV-A7-USSR- (USSR-pcDNA3) ja CV-A7-Parkerisolaattien (Parker-TA) genomit. Menetelmää käytettiin myöhemmin muiden CV-A7- virusisolaattien (275/58, ET1080 ja SVK) tutkimiseen. Näistä isolaateista eristettiin virus-RNA, joka käännettiin cDNA:ksi RT-entsyymillä. PCR:ssä käytetyt, CV-A7- spesifiset koettimet oli suunniteltu aiemmin sekvensoidun CV-A7-sekvenssin (GenBank AY421765) pohjalta. Infektiivisen kloonin tuottamiseksi USSR-pcDNA3- ja Parker-TA-vektoreista tuotettiin PCR:n avulla (T7-PCR) virusgenomin sisältävä DNAjakso, jonka 5'-päähän muodostui alukkeiden avulla T7RNA-polymeraasipromoottori ja 3'-päähän polyA-häntä. Työssä myös sekvensoitiin ja analysoitiin CV-A7-virusisolaatit Parker, USSR, 275/58, ET1080 ja SVK sekä kloonattiin täyspitkiä virusgenomeja cDNA-muodossa mutaatiokokeita varten. FL-PCR:n optimointi onnistui, ja neljä viidestä CV-A7-isolaatista sekvensoitiin. Virusgenomien pituus vaihteli 7403–7405 nt:n välillä. CV-A7-ET1080, -Parker ja - USSR osoittautuivat yli 99 % ja CV-A7-275/58 82,6 % nt samankaltaisiksi koko genomin pituudelta AY421765:en suhteen. Yksittäisten geenien ja proteiinien osalta CV-A7-275/58 oli 75,8–90,4 % nt ja 93,7–98,8 % aa samankaltainen muiden suhteen. Simplot-analyysissä 3B-geenialue oli heterogeenisin. CV-A7-SVK-isolaatti osoittautui echovirus kolmeksi. Infektiivistä kloonia ei saatu tuotettua T7-PCR-tuotteista.