There is lack of evidence on which of the two highly recommended malaria prevention methods, insecticide treated bednets and indoor residual spraying, is more effective than the other. There is also limited peer reviewed literature that compares the characteristics of people who use the two malaria prevention methods. Based on the Health Belief Model, the research questions tested whether there is any relationship between the use of mosquito bednet or the use of indoor residual spraying and contracting malaria, and whether there is any relationship between sociodemographic and socioeconomic factors and the use of malaria prevention methods. Using a quantitative research design, secondary data from the 2011 Angola malaria indicator survey were analyzed. Chi-square for association, logistic regression, and multinomial logistic regression tests were used. There was no statistically significant association between the use of mosquito bednet and having malaria. However, the use of indoor residual spraying significantly reduced the likelihood of getting malaria. There was also a statistically significant association between place of residence, wealth index, level of education, and number of household members and using mosquito bednet and between wealth index and using indoor residual spraying. In conclusion, the malaria prevention programs should focus on indoor residual spraying. It is recommended that all households in southern Africa malaria prone areas should be regularly sprayed. The findings of this study contribute to positive social change in the sense that by using more effective malaria prevention method, individuals will be able to function normally on daily basis, save on expenses related to employment loses or treatment and care of the sick, as well as loss of life and improve own economic status.

Background: Malaria causes over 400,000 estimated deaths annually worldwide, with about 90% in sub-Saharan Africa. Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are two vector-control interventions proven to reduce malaria transmission, but their use together compared to separate has shown mixed results. Methodology: We used a mathematical model to examine the impact of LLINs and IRS on malaria transmission. Time-series analyses and basic reproductive numbers (R0) were developed using MATLAB. We also assessed IRS timing and performed a sensitivity analysis on R0. Results: Modelling scenarios combining LLINs with IRS were similar to those with LLINs alone. Shorter IRS impulses had greater reductions in mosquito populations. The LLIN feeding-inhibition rate was a key parameter with a negative correlation to R0. Discussion/Conclusion: We developed an understanding of the effect of vector-control strategies on malaria transmission. IRS, when paired with LLINs, showed only small improvements in reducing malaria transmission compared to LLINs alone. These results can assist vector-control programmes.

Background Malaria remains a serious epidemic threat in the Lowveld region of Mpumalanga Province. In order to appropriately target interventions to achieve substantial reductions in malaria morbidity and mortality, there is a need to assess the impact of current control interventions such as indoor residual spraying (IRS) for vector control. This study aimed to assess long-term changes in the burden of malaria in Mpumalanga Province during the past eight years (2001-2009) and whether IRS and climate variability had an effect on these changes. Methods All malaria cases and deaths notified to the Malaria Control Programme, Department of Health was reviewed for the period 2001 to 2009. Data were retrieved from the provincial Integrated Malaria Information System (IMIS) database. Climate and population data were obtained from the South Africa Weather Service and Statistics South Africa, respectively. Descriptive statistics were computed to determine any temporal changes in malaria morbidity and mortality. Autoregressive integrated moving average (ARIMA) models were developed to assess the effect of climatic factors on malaria. Results Within the eight-year period of the study, a total of 35,191 cases and 164 deaths-attributed to malaria were notified in Mpumalanga Province. There was a significant decrease in the incidence of malaria in Mpumalanga Province from 385 in 2001/02 to 50 cases per 100,000 population in 2008/09 (P < 0.005). The overall incidence and case fatality rates were 134 cases per 100,000 and 0.54%, respectively. Malaria incidence and case fatality rate by gender showed significant differences, higher in males than in L.M. Ngomane University of Pretoria, 2012 iv females (166.9 versus 106.4; P < 0.001; CFR 0.41% versus 0.55%). The incidence of malaria increased from age 5-14 years (70), reaching a peak at age 25-34 years (190), declining thereafter (50 in those >65 years). Mortality due to malaria was higher in those >65 years, the mean CFR reaching a 2.1% peak. Almost half (47.8%) of the notified cases originated from Mozambique and Mpumalanga Province itself constituted 50.1%. The distribution of malaria varied across the districts, highest in Ehlanzeni district (96.5%), lowest in Nkangala (<1%) and Gert Sibande (<1%). A notable decline in malaria case notification was observed following the increased IRS coverage from 2006/07 to 2008/09 malaria seasons. A distinct seasonal transmission pattern was found to be significantly related to changes in rainfall patterns (P = 0.007). Conclusion Decades of continuous IRS with insecticides have proved to be successful in reducing the burden of malaria morbidity and mortality in Mpumalanga Province between 2001 and 2009. A decline of above 50% in malaria morbidity and mortality was observed following expanded IRS coverage. These results highlight the need to continue with IRS together with other control strategies until interruption in local malaria transmission is completely achieved and alternative vector control strategies implemented. Efforts need to be directed towards the control of imported cases, interruption of local transmission and focus on research into sustainable and cost-effective combination of control interventions. / Dissertation (MSc)--University of Pretoria, 2012. / School of Health Systems and Public Health (SHSPH) / Unrestricted

Past and present uses of DDT and pyrethroids have led to their incorporation into humans, mainly through the food chain and sometimes by direct exposure. The present work focuses on establishing the levels of DDT, its analogous compounds (DDE and DDD), and pyrethroids in humans and the human environment in Manhiça, a rural area where they have been used as insecticides for indoor residual spraying (IRS) and insecticide treated nets (ITN) in malaria control programs. Thatch samples from human dwellings, breast milk from pregnant women and cord blood from newborns were analyzed for assessment of the concentration levels of these compounds. The results showed that DDT and its analogues were already present in humans and dwellings before reintroduction of this insecticide for IRS. As consequence of these applications DDT concentrations increased significantly. The higher proportion of 4,4’-DDT than 4,4’-DDE evidenced that the observed amounts were due to recent applications of this insecticide. Concerning pyrethroids, their presence has been identified in both breast milk and human dwellings showing that both agricultural applications and use for ITN may be responsible for their occurrence in humans and human environments of Manhiça. / L’ús en el passat i en temps actuals del DDT i piretroides ha donat lloc a la seva incorporació en els humans, principalment mitjançant la cadena tròfica i a vegades per exposició directa. Aquest treball té com objectiu establir els nivells de DDT i els seus compostos anàlegs (DDE i DDD), i piretroides en humans i l’ambient humà a Manhiça, una àrea rural on aquests s’han utilitzat com insecticides per aplicació interna (indoor residual spraying, IRS) i tractament de xarxes de protección (insecticide treated nets, ITN) en programes de control de la malària. Per a esbrinar els nivells de concentració d’aquests compostos s’analitzaren mostres de palla de cabanes, de llet materna i de sang de cordó de nou nats. Els resultats mostraren que el DDT i els seus compostos anàlegs ja eren presents en humans i cabanes abans de la reintroducció d’aquest insecticida per IRS. L’ús del DDT en aquest programa féu augmentar considerablement les concentracions d’aquest insecticida. La major proporció de 4,4’-DDT que 4,4’-DDE posà de manifest que les quantitats observades corresponien a aplicacions recents d’aquest insecticida. Respecte als piretroides, s’han trobat en mostres de llet materna i cabanes tot mostrant que tant les aplicacions agrícoles com el seu ús en ITN poder esser la causa de la seva presència en els humans i els ambients humans de Manhiça.

Malgré les efforts national et international pour contrôler le paludisme, de nombreux pays d’Afrique Sub-saharienne restent à risque d’infection, de morbidité et de décès liés au paludisme. L’objectif de cette thèse est d’évaluer l’efficacité « théorique » et l’efficacité « réelle » des outils de la lutte anti-vectorielle (LAV) en utilisant des indicateurs parasitologiques et cliniques. Pour évaluer l’efficacité « théorique » d’une mesure de LAV (étude expérimentale), il faut effectuer un essai contrôlé randomisé à unité de randomisation collective. L’évaluation de l’efficacité « réelle » des outils de LAV est possible grâce à l’utilisation d’un essai contrôlé randomisé à condition que le groupe témoin soit couvert au minimum par les moustiquaires imprégnées d’insecticide à longue durée d’action (MILD) de référence ou les outils de LAV déjà en utilisation dans la population d’étude. Mais, elle nécessite d’énormes moyens techniques, logistiques et financiers. Les résultats de cet essai ont permis de noter que ni la couverture universelle en MILD, ni les combinaisons de MILD+Pulvérisation intra-domiciliaire (PID) ou de MILD+bâches imprégnées d’insecticides n’ont pas apporté une protection supplémentaire contre l’infection et l’accès palustre non compliqué (APNC) par rapport à la MILD en couverture sélective. L’évaluation de l’efficacité réelle des outils de LAV en post-distribution requiert un type d’étude épidémiologique plus souple dans la faisabilité. Face aux contraintes éthiques et financières de l’étude longitudinale, nous avons validé l’utilisation d’une étude cas-témoin à cet effet. Elle a été réalisée en premier chez les enfants de 0-5 ans puis appliquée à toute la population. Les résultats obtenus indiquent que l’efficacité des MILD est variable d’une région à l’autre. En zone rurale, les MILD ont conféré sur l’APNC une efficacité de 40-50 % en ouverture sélective en MILD chez les enfants de zéro à cinq ans. Une réduction de 49 % des APNC a été notée dans toute la population si les MILD (en couverture universelle) sont associées à la PID. En zone urbaine, les MILD en couverture universelle n’ont pas permis de réduire le nombre d’APNC dans toute la population. Elles ont cependant permis une réduction de 50 % des infections palustres dans un seul quartier de la zone d’étude. Les limites de cette étude cas-témoin peuvent être intrinsèques aux mesures de lutte (défaut de couverture, résistance des vecteurs aux insecticides etc.). La mesure de l’exposition peut également être soumise à des biais. Plusieurs facteurs interférant avec la réussite de la LAV ont été évoqués. Le premier facteur défavorable à l’efficacité de la MILD est son défaut d’utilisation. De même, la description de la pièce où se joue la LAV montre que l’espace disponible pour que tous les acteurs puissent jouer convenablement leur rôle (MILD, PID, Homme et vecteur) est assez restreint. Cet espace est souvent mal éclairé. De même la présence des flammes libres participe à la dégradation de l’intégrité physique des MILD. La présence de trous sur les moustiquaires indique une perte de leur efficacité car à partir d’un certain indice > 100, les individus sont fortement exposés aux piqûres de vecteurs. En plus, An. funestus, un des principaux vecteurs assurant la transmission dans les zones d’études concernées peut piquer au-delà de 6 h du matin et assure une bonne partie de la transmission à l’extérieur des habitations. Enfin, les moustiquaires peuvent également créer des dommages corporels à partir d’incendie auxquelles elles participent de part leur caractère inflammable. A l’étape actuelle de la lutte contre le paludisme, il est nécessaire de trouver de meilleurs outils pour améliorer la qualité de la prévention par la LAV. La recherche opérationnelle nous semble en outre primordiale dans la mesure où les outils de LAV utilisés à large échelle ont déjà fourni de bons résultats d’efficacité au laboratoire. / Despite national and international efforts, malaria remains a major public health in many countries. Health systems are hindered by the lack of information on the actual burden of malaria and the effectiveness of vector control tools. Vector-control measures are a component of integrated malaria control strategies. The objective of our thesis was to evaluate the efficacy and the effectiveness of malaria vector control tools using parasitological and clinical criteria.With a block randomized control trial, we investigated whether the combination of long-lasting insecticidal mosquito nets (LNs) with indoor residual spraying (IRS) or Carbamate-treated Plastic Sheeting (CTPS) conferred better protection against malaria vectors than did LNs alone. The clinical incidence density of malaria was not reduced in the children from the "Universal LN" group (incidence density rate (0.95, 95% CI 0.67–1.36, p=0.79), nor in those from the "Target LN + IRS" group (1.32, 0.90–1.93, p=0.15) or from the "Universal LN + CTPS group (1.05, 0.75–1.48, p=0.77) compared with the reference group "Target LN". The same trend was observed with the prevalence and parasite density of asymptomatic infections. The evaluation of the effectiveness of vector control tools is possible but requires enormous technical, logistic and financial resources. The evaluation of the effectiveness of malaria vector control tools after distribution requires a more flexible epidemiological study. Considering the ethical and financial constraints of the longitudinal study, we validated the use of a case-control study to this purpose. It was conducted primarily among children aged 0-5 years old and then applied to the entire population. Results were spatial dependant when taking into account age and compliance to chemoprophylaxis as confusion factors, use of other vector control tools, sex, and economic status, school level of the mother or the head of the house. In the rural area, the use of LNs provided significant level of protection (40-50%) against clinical cases among children aged 0-5 years old. This significant protection was obtained among all population only if the LNs were associated to IRS. In the urban area, the use of LN was not provided protection against clinical cases but reduce 50% of the risk of Plasmodium falciparum infection in one neighbourhood. The limits of this case-control study may be intrinsic to control measures (lake of coverage, vector resistance to insecticides etc.). The exposure of vector control tools measures may also be subject to bias. Several factors interfering with the success of malaria control were discussed. The first negative factor to the effectiveness of vector control tools was the "no use of LNs". Then follows the immediate environment where the fight against vectors took place. The description of the room where played vector control fighting shows that the space available for all the actors (LNs, IRS, humans and vectors) to play their role properly is quite limited. This space is often poorly enlightened. Similarly the presence of open flames is involved in the degradation of the physical integrity of LNs. The presence of holes on the bed-nets indicates a loss of effectiveness because from a hole index above 100, individuals are highly exposed to the bites of vectors. In addition, An. funestus, one of the main vectors of malaria transmission in the study area, bitted after 6:00 am and provides much of the transmission in outdoor. Finally, the nets can also create personal injury as fire. At the end our work, we conclude that the innovative vector control tools are required to improve malaria vector control. But, operational research seems now essential as the vector control tools used on a large scale have provided good efficacy results in the laboratory. The challenge then is to obtain comparable results in real condition of use and look for effectiveness barriers.