Production of Urban Space and the occurrence of malaria in the Brazilian Amazon: the Porto Velho case

Due to intense ongoing urbanization in the Amazon, the urban pattern of malaria may be changing, both in its spatial distribution and epidemiological profile. The purpose of this paper is to analyze how the process of production of urban space in Porto Velho, the capital of the state of Rondonia, Brazil has contributed to the occurrence and maintenance of urban malaria. Using data collected from the Malaria Epidemiological Surveillance System (SIVEP-Malaria), we calculated malaria indices for the districts of Porto Velho from 2005 to 2018. We also developed two typologies for classifying urban space based on functional characteristics and features of the landscape. While the former considers characteristics of urban space in Porto Velho, the latter is based on suitability for malaria vectors. We found that the annual parasite index declined in Porto Velho during the study period. However, changes in the index were not uniform across the districts of the city. Periurban areas showed no decline in the index, which we attribute to these areas’ high vegetation density and hydrological characteristics.

Human mobility and urban malaria risk in the main transmission hotspot of Amazonian Brazil

Malaria in the Amazon is often perceived as an exclusively rural disease, but transmission has been increasingly documented within and near urban centers. Here we explore patterns and causes of urban-to-rural mobility, which places travelers at risk of malaria in Mâncio Lima, the main malaria hotspot in northwestern Brazil. We also analyze rural-to-urban mobility caused by malaria treatment seeking, which poses an additional risk of infection to urban residents. We show that the rural localities most frequently visited by urban residents–typically farming settlements in the vicinity of the town–are those with the most intense malaria transmission and also the most frequent source localities of imported malaria cases diagnosed in the town. The most mobile urban residents are typically poor males 16 to 60-years old from multi-sited households who lack a formal job. Highly mobile residents represent a priority target for more intensive and effective malaria control interventions, that cannot be readily delivered to the entire community, in this and similar urbanized endemic settings across the Amazon.

Urban malaria prevalence and its associated risk factors: the case of Batu town, East Shoa, Oromia Regional State, Ethiopia

Background- Malaria is one of the leading causes of morbidity and mortality particularly in sub-Saharan Africa including Ethiopia. Approximately, 68% of its population is at a risk of malaria infection and nearly three-fourth of the Ethiopia landmass is considered as malarious. Most of the malaria related researches are being conducted in the rural areas; however, urban malaria should be also targeted without which malaria elimination is impossible. Therefore, the aim of this study was to assess the magnitude of malaria, prevalence of P. falciparum and P. vivax and its associated risk factors during low transmission season (April to July, 2018) in Batu town, East Shoa, Oromia Regional state, Ethiopia.Methods – Finger pricked blood samples were collected from 356 febrile individuals visiting health facilities in Batu town from April to July, 2018 supplemented with questionnaire survey to assess socio-demographic and risk factors associated with malaria infection.Results – In the current study an overall prevalence of 17.13% (61/356) malaria infection was observed of which 50.8% (31/61) were positive for P. vivax, 45.95% (28/61) were positive for P. falciparum and 3.3% (2/61) were mixed infections of P. falciparum and P. vivax. Male individuals (32 (9%)) were more infected with malaria than females (29 (8.2%)). Sex had no statistical significance association with malaria (χ2 = 2.026, P = 0.156). Logistic regression analysis revealed that individuals who possessed ITN (OR = 0.38, 95% CI (0.194, 0.743) and P = 0.005) and whose houses were sprayed with insecticides (OR = 0.18, 95% CI (0.097, 0.34) and P < 0.001) were found less likely to get malaria infection. Individuals living closer to stagnant water had more chance (almost three-fold times) of malaria infection than those who were found at a distant from stagnant water (OR= 2.97, 95% CI (1.68, 5.26) and P < 0.001).Conclusion- The current study revealed that malaria is still public health problem in Batu town, which might indicate the same in other urban areas of the country. Therefore, in order to get the national picture about the prevalence of urban malaria and its associated risk factors, we recommend large scale investigation of the situation.

Modelling and mapping the intra-urban spatial distribution of Plasmodium falciparum parasite rate using very-high-resolution satellite derived indicators

Background The rapid and often uncontrolled rural–urban migration in Sub-Saharan Africa is transforming urban landscapes expected to provide shelter for more than 50% of Africa’s population by 2030. Consequently, the burden of malaria is increasingly affecting the urban population, while socio-economic inequalities within the urban settings are intensified. Few studies, relying mostly on moderate to high resolution datasets and standard predictive variables such as building and vegetation density, have tackled the topic of modeling intra-urban malaria at the city extent. In this research, we investigate the contribution of very-high-resolution satellite-derived land-use, land-cover and population information for modeling the spatial distribution of urban malaria prevalence across large spatial extents. As case studies, we apply our methods to two Sub-Saharan African cities, Kampala and Dar es Salaam. Methods Openly accessible land-cover, land-use, population and OpenStreetMap data were employed to spatially model Plasmodium falciparum parasite rate standardized to the age group 2–10 years (PfPR2–10) in the two cities through the use of a Random Forest (RF) regressor. The RF models integrated physical and socio-economic information to predict PfPR2–10 across the urban landscape. Intra-urban population distribution maps were used to adjust the estimates according to the underlying population. Results The results suggest that the spatial distribution of PfPR2–10 in both cities is diverse and highly variable across the urban fabric. Dense informal settlements exhibit a positive relationship with PfPR2–10 and hotspots of malaria prevalence were found near suitable vector breeding sites such as wetlands, marshes and riparian vegetation. In both cities, there is a clear separation of higher risk in informal settlements and lower risk in the more affluent neighborhoods. Additionally, areas associated with urban agriculture exhibit higher malaria prevalence values. Conclusions The outcome of this research highlights that populations living in informal settlements show higher malaria prevalence compared to those in planned residential neighborhoods. This is due to (i) increased human exposure to vectors, (ii) increased vector density and (iii) a reduced capacity to cope with malaria burden. Since informal settlements are rapidly expanding every year and often house large parts of the urban population, this emphasizes the need for systematic and consistent malaria surveys in such areas. Finally, this study demonstrates the importance of remote sensing as an epidemiological tool for mapping urban malaria variations at large spatial extents, and for promoting evidence-based policy making and control efforts.

Urban Malaria Prevalence and Its Associated Risk Factors: The Case of Batu Town, East Shoa, Oromia Regional State, Ethiopia

Background- Malaria is one of the leading causes of morbidity and mortality particularly in sub-Saharan Africa including Ethiopia. Approximately, 68% of its population is at a risk of malaria infection and nearly three-fourth of the Ethiopia landmass is considered as malarious. Most of the malaria related researches are being conducted in the rural areas; however, urban malaria should be also targeted without which malaria elimination is impossible. Therefore, the aim of this study was to assess the prevalence of malaria and its associated risk factors in Batu town, Oromia Regional state, Ethiopia.Methods – Finger pricked blood samples were collected from 356 febrile individuals visiting health facilities in Batu town from April to July, 2018 supplemented with questionnaire survey to assess socio-demographic and risk factors associated with malaria infection.Results – In the current study an overall prevalence of 17.13% (61/356) malaria infection was observed of which 50.8% (31/61) were positive for P. vivax, 45.95% (28/61) were positive for P. falciparum and 3.3% (2/61) were mixed infections of P. falciparum and P. vivax. Males (32 (9%)) were more infected with malaria than females (29 (8.2%)). Sex had no statistical significance association with malaria (χ2 = 2.026, P = 0.155). Logistic regression analysis revealed that individuals who possessed ITN (OR = 0.38, 95% CI (0.194, 0.743) and P = 0.005) and whose houses were sprayed with insecticides (OR = 0.18, 95% CI (0.097, 0.34) and P <0.001) were found less likely to get malaria infection. Individuals living closer to stagnant water had more chance of malaria infection than those who were found at a distant from stagnant water (OR = 0.34, 95% CI (0.19, 0.59) and P<0.001).Conclusion- The current study revealed that malaria is still public health problem in Batu town, which might indicate the same in other urban areas of the country. Therefore, in order to get the national picture about the prevalence of urban malaria and its associated risk factors, we recommend large scale investigation of the situation.