The thesis is concerned with what should be done to decrease the incidence of human salmonellosis in Canada. The present high incidence of Salmonella contaminated poultry is reviewed and evidence is given that links Salmonella contaminated poultry carcasses at the retail level to human salmonellosis. The question is raised as to whether control or eradication should be the goal in Canada, and present regulations involving various levels of Governments are examined. The incidence of Salmonella contaminated poultry in some other countries is reviewed, together with some of the Salmonella control programmes that have been instituted by these countries. Finally, certain recommendations are made, as to what could be done in Canada to decrease the incidence of human salmonellosis. These recommendations stress the need for further research to develop ways of decreasing the incidence of Salmonella contaminated poultry at the retail level. The colonization of the gut of day-old chickens with the intestinal flora of adult chickens is a method that shows promise. The use of radiation and chlorination of the poultry carcasses would also help to reduce the incidence of carcass contamination. If Canada is determined to reduce human salmonellosis, then steps must be taken to coordinate the many different branches of both the Federal and Provincial Governments, and regulations, when promulgated, must be enforced. Caterers and those cooking in their own homes must be educated on correct food handling practices and cooking techniques. Human salmonellosis will probably never be eradicated, but its present incidence could certainly be reduced. / Medicine, Faculty of / Population and Public Health (SPPH), School of / Graduate

Objective: To determine whether dosage adjustment of enoxaparin during pregnancy, in order to maintain a peak anti-Xa of 1.0-1.2 U/ml, is safe for women with mechanical prosthetic heart valves (MPHV). Methods: This was a prospective observational study performed at Charlotte Maxeke Johannesburg Academic Hospital from 2007 to 2009. 15 women with MPHVs were treated with enoxaparin with dosage adjustment throughout pregnancy to achieve a peak anti-Xa of 1.0-1.2 U/ml. Main outcomes measured were prosthetic valve thrombosis, bleeding and maternal mortality. Results: There was no maternal mortality. None of the women developed valvular thrombosis during pregnancy. Two women developed epistaxis and another developed spotting per vagina. There was no foetal mortality. Conclusion: Our data show that enoxaparin may be administered safely during pregnancy to pregnant women with mechanical prosthetic heart valves when there is dosage adjustment throughout pregnancy in order to maintain an anti-Xa of 1.0-1.2 U/ml.

A dissertation submitted to the Faculty of Health Sciences, University of Witwatersrand, Johannesburg in fulfillment of the requirements for the degree of Master of Science in Medicine, Johannesburg , 2013 / South Africa’s Prevention of Mother-to-Child Transmission (PMTCT) programme is critical for eliminating vertical HIV transmission and reducing infant mortality. Early treatment of HIV-infection to curb infant deaths requires earlier diagnostic testing than the currently recommended six-week test. This study describes the continuum of PMTCT care at a Johannesburg hospital to identify interventions for improvement and investigates birth HIV testing for infants. Data from a cohort study at the hospital evaluating diagnostic assays in HIV-exposed infants were collated with routine clinical data, validated and analysed. Among 838 mother-infant pairs, 38% of mothers attended antenatal clinics early enough to receive optimal antenatal prophylaxis. Only 72% of infants accessed six-week testing at the hospital; a further 10% underwent testing elsewhere. Of 38 HIV-infected infants, 29 were infected in-utero and could have been identified at birth (sensitivity of 76.3% for birth testing), compared to only 26 (68%) diagnosed by six-week testing at the hospital. Majority (88%) of these 26 infants accessed antiretroviral therapy, but treatment was only initiated at a median age of 16.0 weeks and 43% of HIV-infected infants who initiated treatment had defaulted or died before the end of the study. Mathematical modelling demonstrated that birth testing would be superior to a six-week test to maximise infants diagnosed and life years saved, with the ideal algorithm being a birth and ten-week test. The PMTCT programme can be enhanced by earlier antenatal care for women and earlier infant diagnosis. Birth testing would diagnose HIV-infection before infants die or default from the PMTCT programme, thereby enabling effective monitoring of MTCT, and would allow earlier treatment initiation to reduce early infant mortality.

Thesis (M.Sc.D.)--Boston University, School of Graduate Dentistry, 1975. Periodontology. / Includes bibliographic references: leaves 112-131. / One hundred-twenty subjects were assigned to AP-100 enzyme mouthwash, used twice daily, in a doubleblind treatment schedule for six weeks. They were divided equally into Part A and Part B, sixty subjects each. In Part A, subjects ,vere scored, then half of them were randomly assigned to placebo and half to AP-100 enzyme. Removal of pre-existing plaque and treatment of gingivitis only were considered in this part. Part B, focused on reducing plaque accumulation and treatment of gingivitis. Therefore, all subjects in Part B underwent complete prophylaxis with a base line score equal to zero. Gingivitis only was scored in this group and the subjects were randomly assigned half to AP-100 and the other half to placebo. Plaque and gingivitis were scored at three and six weeks. [TRUNCATED]

Malaria is transmitted by the mature, blood feeding portion of mosquito vector populations. Malaria vector control programs based on indoor residual spraying (IRS) of insecticides are designed to target resting adult Anopheles mosquitoes before or after they have blood fed. When a female mosquito acquires a blood meal, she could also ingest harmful xenobiotics that are present in the blood. During the resting period after feeding, many processes are initiated in order to assist in the digestion and assimilation of the blood. Ultimately, this enables the mosquito to absorb those amino acids needed for the biosynthesis of yolk proteins, which are essential for subsequent egg maturation. Since the regulation of xenobiotic (including insecticides) detoxification enzyme systems is likely to be altered in response to the ingestion of blood, this study aimed to investigate the effect of a blood meal on insecticide tolerance in insecticide resistant and susceptible southern African strains of the major malaria vector Anopheles funestus. Through the use of CDC bottle bioassays it was demonstrated that blood fed An. funestus carrying a pyrethroid resistant phenotype are even more tolerant of pyrethroid intoxication than their unfed counterparts. Using another major malaria vector, An. gambiae, microarray analysis revealed that a general increase in delta class glutathione-s-transferase (GST) expression occured in response to a blood meal. One gene, GSTD3, was over-expressed in both blood fed An. gambiae and An. funestus. Although this gene could not be validated with real time quantitative PCR, it serves as a viable target for future investigations. Since the pyrethroid resistant phenotype of southern African An. funestus has been linked to the over-expression of the duplicate copy gene CYP6P9, the expression levels of both copies of this gene were investigated. CYP6P9 and its copy, CYP6P13, showed a small but significant increase in expression in response to a blood meal. The increased expression of these major effect genes in response to blood feeding may be responsible for the increase in insecticide tolerance seen in the bottle bioassays. In an effort to repeat these experiments on wild caught An. funestus, field material was collected from Karonga in northern Malawi. Specimens were morphologically identified as members of the An. funestus group. However, attempts to molecularly identify them to species level failed. Through the use of ITS2 and D3 sequence analysis, cytogenetics and cross mating studies it was possible to conclude that these wild caught specimens were a new species. They have been provisionally named An. funestus-like.

A research report submitted to the Faculty of Health Sciences, School of Public Health, University of the Witwatersrand, South Africa, in partial fulfilment of the requirements for the degree of Masters in Public Health-Social and Behaviour Change Communication.November 2012 / Aim of the study: The main aim of this study was to determine socio-demographic characteristics associated with being diagnosed with TB by a health care worker among adult males and females aged between18-49 years in Ntcheu district, Malawi. Method: This was a descriptive and analytical cross-sectional study. A total of 121 adult women and men were sampled using a three-stage simple sampling technique. The 2008 Population and Housing Census enumeration areas (EAs) were used as a sampling frame. The first stage involved simple sampling of two Traditional Authorities (TAs) out of nine (9). Stage two involved selection of ten villages in each sampled TA. The third level of sampling was a selection of six households from each selected village where the first dwelling was also sampled. A structured questionnaire was developed in English and translated into Chichewa. The questionnaire was administered by a trained interviewer at each respondent’s household. Three research assistants were employed to collect data. Results The awareness of TB was universal with every participant reporting that they had heard about TB. Of the 121 participants, more than half were male (53.7%; n=65).The median age of the respondents was 28 years (range 18-49 years) and approximately a third of the respondents (34.4%; n=31) had 1-2 children. The study found that higher education (p=0.01), higher ownership of household assets (p=0.01), higher average monthly household income (p=0.02) and higher socio-economic status of the respondents (p=0.01) were significantly associated with higher knowledge of causes of TB. It was found that education was also associated with knowledge of the transmission of TB (P=0.01). The lower the level of education the lower the knowledge level on the correct modes of TB transmission. There was also an association between knowledge of symptoms of TB and occupation (p=0.05). It was found that farmers were less likely to know symptoms of the disease compared to other forms of occupation namely: business persons, those participants who were employed and those not employed. The study found that women had significantly lower risk perceptions of the disease (p=0.01). No association was found between socio-economic and cultural factors of the respondent and self-reported TB diagnosis. Conclusion The findings of this study show that a comprehensive health promotion programme is required in order to address significant gaps on knowledge of causes of TB, transmission, symptoms and risk perceptions and other related socio-economic and cultural factors in Ntcheu district.

The aim o f the study w as to determ ine the know ledge and concerns about HIV/AIDS among childbearing w om en in M ahalapye, Botswana. A descriptive study design using an inri-view schedule was used. The sam ple o f 166 respondents (aged 18-29 years) w as draw n from a population o f w om en w ho attended M ahalapye clinics. D ata w ere analysed by use o f a com puter and descriptive statistics including frequencies and percentages. The dem ographic data showed that the m ajority (85.5%) o f the respondents w ere not m arried, o f w hom 78% had partners and 9% w ere cohabiting. Seventy percent had secondary education and 70.4% w ere unem ployed, hence their dependence on their partners and relatives for econom ic support. The results show ed that the respondents had a high level o f know ledge about HIV/AIDS including risk factors, m ode o f transm ission and prevention. A ll respondents (100%) seem to be aware that a person can contract H IV through having m ultiple sexual partners. The m ajority (98%) stated that H IV can be transm itted sexually and 97% said that infected pregnant w om en can transm it H IV to their babies. N inety seven percent o f w om en said that the spread o f H IV can be prevented by \ h g condom s, 21.1 % said by having sex less frequently and 98.8% said people can protect them selves from contracting H IV by through sharing utensils and food w ith an infected person, 38% believed that mosquitoes and insects can transm it H IV and 41.6% did not believe that a person infected with HIV m ight look healthy. Thirty six (21.7% ) w om en perceived them selves not to be at risk o f H IV ow ing to current m onogam ous relationships and their trust in their partners. Radio and health personnel w ere m entioned as the m ain sources o f inform ation about HIV/AIDS. All (100% ) respondents revealed that they w ere afraid o f becom ing infected w ith the virus and 98.2% said that they w ere concerned that m en do not like using condom s. Even though 93.4% said that they w ere free to discuss sexual activities w ith their partners, 83.7% said that they w ould not find it easy to reveal their H IV status to their partner for fear o f rejection and stigm atisation. The results show ed that know ledge was related to education level. A ll w om en w ho had post secondary education indicated that AIDS cannot be cured by consulting traditional doctors ( 9 -0 0v'7) and W estern doctors (p=0.046) as com pared w ith those w ho did /iOf hav-'-post secondary education. A ge and m arital status seem not to be related to know ledge (p>0.05). Educational program m es targeted at these w om en should address the m isconceptions about the m ode o f transm ission. W om en should be equipped w ith effective com m unication and decision m aking skills that w ill em power them to adopt behaviours that will protect them from becom ing infected or infecting others. Further research is needed to determ ine the extent to w hich concerns expressed by w om en in this study are expressed by other groups o f women.

Hypertensive left ventricular hypertrophy (LVH) increases the risk for the development of heart failure with systolic chamber dysfunction. However, the exact mechanisms and hence best therapeutic approach to prevent this transition process is uncertain. One potential mechanism is through excessive β-adrenergic receptor (-AR) activation, but the risks of β-AR blocker therapy may outweigh the benefits. Since activation of -AR augments function of the renin-angiotensin-aldosterone system, I therefore explored whether mineralocorticoid receptor (MR) blockade prevents the transition from hypertensive LVH to systolic chamber decompensation produced by excessive β-AR activation, and the mechanisms thereof. The role of hypertensive LVH as a predisposing factor to systolic chamber decompensation post-myocardial infarction (MI) is controversial. In the present thesis I therefore also evaluated this question. The effect of spironolactone (SPIRO, 80 mg.kg-1.day-1), an MR blocker, on LV chamber remodelling and function was evaluated in spontaneously hypertensive rats (SHR) in whom decompensation was induced by administering a low dose of the -AR agonist, isoproterenol (ISO) for 4.5 months. ISO administration resulted in an increased urinary aldosterone excretion and LV cavity dimensions, a right shift in LV diastolic pressure-volume relations, and a decreased LV relative wall thickness without further enhancing an increased myocardial norepinephrine (NE) release in SHR. ISO reduced LV systolic chamber function (decreased LV endocardial fractional shortening and the slope of the LV systolic pressure- volume relationship) without modifying intrinsic myocardial systolic function (as assessed from LV midwall fractional shortening and the slope of systolic stress-strain relationship). SPIRO abolished ISO-induced chamber dilatation, wall thinning and systolic dysfunction, but failed to modify blood pressure, volume preloads, intrinsic myocardial systolic function, or myocardial NE release. These results suggest that MR activation, through load-independent effects, may be critical in mediating the transition from compensated hypertensive LVH to dilatation and LV systolic chamber dysfunction. In SHR, ISO increased myocardial matrix metalloproteinase (MMP)-2 activity (zymography) after only 4-5 days of administration, a change that was associated with MMP-2, but not TIMP expression. The increased MMP-2 activity persisted until 4.5 months of the study and these changes were prevented by SPIRO. At 4.5 months, ISO resulted in increased non-cross-linked, but not cross-linked myocardial collagen concentrations in SHR, an effect that was abolished by SPIRO. Although at 4.5 months ISO administration was not associated with an increased cardiomyocyte apoptosis (TUNEL), an early (4-5 days) ISO-induced apoptotic effect was noted, which was prevented by SPIRO. Neither ISO nor SPIRO influenced cardiomyocyte length (image analysis and flow cytometry) in SHR. Thus MR blockade may prevent the adverse effects of β-AR activation in hypertensive LVH through alterations in the cardiac interstitium and cardiomyocyte apoptosis. Six-to-seven months after ligation of the left anterior descending coronary artery, LV myocardial systolic function as assessed from % shortening of the non-infarcted lateral wall segmental length determined over a range of filling pressures (ultrasonic transducers placed in the lateral wall in anaesthetized, open-chest, ventilated rats) and % thickening of the posterior wall (echocardiography) was reduced in infarcted SHR (SHR-MI) (p<0.05), but not in normotensive Wistar Kyoto (WKY-MI) animals as compared to corresponding controls (SHR-Sham, WKY-Sham). This change in regional myocardial function in SHR-MI, but not in WKY- MI, occurred despite a similar degree of LV dilatation in SHR-MI and WKY-MI rats and a lack of difference in LV relative wall thinning, LV wall stress, apoptosis (TUNEL) or necrosis (pathological score) between SHR-MI and WKY-MI rats. Although the change in regional myocardial function in the SHR-MI group was not associated with a greater reduction in resting global LV chamber systolic function (endocardial fractional shortening-FSend and end-systolic elastance [LV Ees] determined in the absence of an adrenergic stimulus), in the presence of an ISO challenge a reduction in LV Ees in SHR-MI compared to WKY-MI and SHR and WKY-Sham rats was noted (p<0.04). These data suggest that with chronic MI, the hypertensive heart is susceptible to development of viable tissue myocardial dysfunction, a change which cannot be attributed to excessive chamber dilatation, apoptosis or necrosis, but which in-turn, contributes toward a reduced cardiac adrenergic-inotropic reserve. The present thesis therefore suggests that MR blockade may prevent the transition from hypertensive LVH to systolic chamber decompensation, and that pre-existing hypertensive LVH increases the susceptibility to a depressed LV regional myocardial systolic function in the non-infarcted LV myocardium subsequent to MI, an effect that translates into a reduced inotropic reserve.

Hepatitis B virus (HBV) is a major global public health burden, with over 350 million people chronically infected. This results in approximately 600,000 liver cancer-related deaths annually. Chronic HBV infections are normally managed with long-term anti-HBV therapeutics, such as reverse transcription inhibitors, which target post-transcriptional viral processes without affecting the cccDNA. Treatment failure however is largely as a result of the stability of this episomal viral DNA. The cccDNA minichromosome serves as a reservoir of HBV DNA and is capable of re-establishing viral replication following withdrawal of treatment. Designer nucleases, like transcription activator-like effector nucleases (TALENs), have recently been used to create double stranded breaks (DSBs) at target-specific endogenous DNA loci. These nucleases are designed as pairs, which upon dimerisation cleave double-stranded DNA. Subsequent activation of the cellular non-homologous end-joining (NHEJ) pathway often results in targeted mutagenesis at the DSB site. As TALENs may be designed to bind to any DNA sequence, they are commonly used as genetic engineering agents. Inactivation of HBV cccDNA, using these engineered TALENs, presents a unique approach to disabling viral replication permanently. To investigate this, a panel of TALENs targeting the core (C), surface (S) and two different polymerase (P1 and P2) regions of HBV cccDNA were generated using a Golden gate modular assembly approach. TALENs were initially tested in two liver-derived cell lines. Firstly as transient co-transfections in Huh7 cells using a HBV replication competent plasmid, followed by long term investigations in HepG2.2.15 cells which model HBV replication in vitro. Inactivation of HBV was determined by measuring markers of viral replication, whilst TALEN-mediated targeted disruption was verified by T7 endonuclease 1 (T7E1) or CELI endonuclease assays and sequencing. In vitro, the S TALEN inhibited HBsAg secretion by 80% in Huh7 cells and 60% in HepG2.2.15 cells. Furthermore, S TALEN-mediated targeted disruption occurred in 35-47% of cccDNA copies, whilst the C TALEN resulted in 11% targeted disruption of cccDNA in without inhibition of HBsAg expression. The P2 TALEN showed no anti-HBV efficacy, however the P1 TALEN inhibited HBsAg expression by up to 60% without any evidence of site-directed cleavage. As this TALEN binding site spans the HBV Enhancer I sequence, knock-down of HBsAg expression is most likely to occur as a result of transient transcriptional repression. To confirm whether permanent repression of HBV transcription could be achieved, a KRAB-based transcription activator-like repressor (rTALE) targeting the HBV pre-S2 promoter was generated. Using an in vitro reporter gene assay, the pre-S2 rTALE inhibited luciferase expression by up to 90%. However this was only achieved using high molar concentrations of the repressor, suggesting multiple rTALEs may improve HBV transcriptional repression. As the S and C TALENs displayed significant anti-HBV efficiency in vitro, they were tested in a murine hydrodynamic injection model of HBV replication. In vivo, the S TALEN inhibited HBsAg secretion by 95% and induced disruption in 77–87% of HBV DNA targets. In addition the C TALEN inhibited HBcAg expression and induced disruption in 78-93% of HBV DNA targets. Additionally, serological analysis showed a reduction in circulating virions and no apparent liver toxicity, as determined by real-time PCR (qPCR) and aspartate transaminase (AST)/ alanine aminotransferase (ALT) liver function tests respectively. Deep sequencing at the S and C TALEN binding sites showed targeted mutagenesis of HBV DNA in samples extracted from murine hepatocytes transfected with TALENs, however wild-type sequences were exclusively detected in mice that had not been treated with anti-HBV TALENs. Furthermore, frameshift deletions were predominantly detected indicating major disruptions in the HBV surface and core sequences. These results indicate that TALENs designed to disable and silence HBV cccDNA are effective both in vitro and in vivo and as such provide a promising therapeutic approach to treat this serious infection.

Anopheles funestus is a major vector of malaria in the southern African region. Insecticide resistance to pyrethroid and carbamate insecticides has been recorded in populations of this species in South Africa and Mozambique. This study aimed to determine the relationship between pyrethroid resistance and gene expression of two closely related genes, CYP6P9 and CYP6P13, by age and sex in a resistant strain An. funestus from southern Africa, FUMOZ-R. The insecticide susceptibility assays showed that percentage survival in both FUMOZ-R sexes significantly decreased as age increased. The mRNA expressions of CYP6P9 and CYP6P13 were higher in FUMOZ-R relative to the insecticide susceptible strain (FANG). The expression of permethrin resistance varies with age in An. funestus FUMOZ-R. The results indicate that other genes may also be involved in insecticide resistance. In addition to this, the expression profile of other metabolic genes involved in insecticide resistance was also investigated. A microarray based approach was used to identify genes differentially expressed in FUMOZ-R and FANG. As the full set of detoxification genes in An. funestus are unknown, this study investigated the utility of the An. gambiae detox chip to screen for differentially expressed detoxification genes in An. funestus. After optimization of the hybridisation conditions, over 90% of the probes showed a positive signal. Only three genes were significantly (P<0.001) differentially expressed in the females, CYP6P9, COI and CYP6M7. The same genes were also significantly differentially expressed in the adult males, together with an additional 21 transcripts. The third part of this study investigated the gene expression in the first instar, fourth instar and 3-day old adults in FUMOZ-R using the An. gambiae detox chip. The variation in metabolic enzyme gene transcription at the different developmental stages in An. funestus are not known. The identification of differentially transcribed genes at the different life stages provides some insight into the role and function of these genes. A large number of cytochrome P450s (monooxygenases), esterases, glutathione S-transferases (GSTs) and other additional genes were differentially expressed in all life stages. This study provided vital information regarding genes potentially involved in pyrethroid resistant and is the first to provide metabolic or detoxifying transcription gene information in An. funestus.