Risk Of Malaria Transmission Research Articles

Impact of cattle on the abundance of indoor and outdoor resting malaria vectors in southern Malawi

BackgroundUnderstanding the blood feeding preferences and resting habits of malaria vectors is important for assessing and designing effective malaria vector control tools. The presence of livestock, such as cattle, which are used as blood meal hosts by some malaria vectors, may impact malaria parasite transmission dynamics. The presence of livestock may provide sufficient blood meals for the vectors, thereby reducing the frequency of vectors biting humans. Alternatively, the presence of cattle may enhance the availability of blood meals such that infectious mosquitoes may survive longer, thereby increasing the risk of malaria transmission. This study assessed the effect of household-level cattle presence and distribution on the abundance of indoor and outdoor resting malaria vectors.MethodsHouses with and without cattle were selected in Chikwawa district, southern Malawi for sampling resting malaria vectors. Prokopack aspirators and clay pots were used for indoor and outdoor sampling, respectively. Each house was sampled over two consecutive days. For houses with cattle nearby, the number of cattle and the distances from the house to where the cattle were corralled the previous night were recorded. All data were analysed using generalized linear models fitted with Poisson distribution.ResultsThe malaria vectors caught resting indoors were Anopheles gambiae sensustricto (s.s.), Anopheles arabiensis and Anopheles funestuss.s. Outdoor collections consisted primarily of An. arabiensis. The catch sizes of indoor resting An. gambiae sensulato (s.l.) were not different in houses with and without cattle (P = 0.34). The presence of cattle near a house was associated with a reduction in the abundance of indoor resting An. funestuss.l. (P = 0.04). This effect was strongest when cattle were kept overnight ≤ 15 m away from the houses (P = 0.03). The blood meal hosts varied across the species.ConclusionThese results highlight differences between malaria vector species and their interactions with potential blood meal hosts, which may have implications for malaria risk. Whereas An. arabiensis remained unaffected, the reduction of An. funestuss.s. in houses near cattle suggests a potential protective effect of cattle. However, the low abundance of mosquitoes reduced the power of some analyses and limited the generalizability of the results to other settings. Therefore, further studies incorporating the vectors’ host-seeking behaviour/human biting rates are recommended to fully support the primary finding.

Impact of an accelerated melting of Greenland on malaria distribution over Africa

Studies about the impact of future climate change on diseases have mostly focused on standard Representative Concentration Pathway climate change scenarios. These scenarios do not account for the non-linear dynamics of the climate system. A rapid ice-sheet melting could occur, impacting climate and consequently societies. Here, we investigate the additional impact of a rapid ice-sheet melting of Greenland on climate and malaria transmission in Africa using several malaria models driven by Institute Pierre Simon Laplace climate simulations. Results reveal that our melting scenario could moderate the simulated increase in malaria risk over East Africa, due to cooling and drying effects, cause a largest decrease in malaria transmission risk over West Africa and drive malaria emergence in southern Africa associated with a significant southward shift of the African rain-belt. We argue that the effect of such ice-sheet melting should be investigated further in future public health and agriculture climate change risk assessments.

Diversity of Anopheles Gambiae s.l., Giles (Diptera: Culicidae) Larval Habitats in Urban Areas and Malaria Transmission in Bouaké, Côte d'Ivoire.

Malaria vectors are supposedly uncommon in urban areas owing to the lack of suitable breeding sites for their development. However, the maintenance in urban areas of traditional rural practices along with humanitarian crisis can create favorable conditions for malaria transmission. This study aimed to provide relevant entomological data on the risk of malaria transmission in the city of Bouaké, after the military-political crisis from 2002 to 2011 in Côte d'Ivoire. Adults mosquitoes were collected by human landing catches in Dar Es Salam, Kennedy and N'gattakro neighborhoods. Potential breeding sites were georeferenced and mapped using a GPS. Mosquito species were identified morphologically and by molecular methods. Plasmodium infections were detected by quantitative PCR. Anopheline larvae were found in rice and vegetable crops, puddles, and footprints. A total of 939 Anopheles gambiae s.l. were caught during the surveys. The average human biting rate was 8.8 bites/person/night. The A. gambiae s.l. species were A. gambiae s.s (89.6%) and Anopheles coluzzii (10.4%). The average infectivity rate was 0.74% and the average annual entomological inoculation rate was estimated at 19 infected bites/person/year ranging from 0 in Dar Es Salam and N'gattakro to 58 in Kennedy. The risk of malaria transmission exists in Bouaké city, although Plasmodium infections are low.

Malaria and Insecticide-Treated Net (ITN) Utilization among Orphans and Vulnerable Children in Nigeria

Abstract Background: The lack of empirical data on the malaria status of orphans and vulnerable children (OVC), access to long-lasting insecticide-treated nets (LLINs), and knowledge about the disease can hamper the development of effective policies and programs to address their malaria-related needs. Aim: The aim of this study was to evaluate knowledge of malaria transmission and utilization of LLINs among OVC in Ondo metropolis, Nigeria. Materials and Methods: A cross-sectional study was conducted in Ondo City, Ondo State, Nigeria, between January and March 2018. The study was carried out among 66 OVC (age 5–19 years) using questionnaires. Information on socio-demography, LLIN utilization, knowledge and risks of malaria transmission among OVC was sought. Results: The use of LLINs (80.9%) among OVC was significantly higher than the use of insecticide spray (6.1%) and mosquito coils (12.1%) (p <0.0001). Knowledge about malaria transmission was relatively high, and the majority of children (60.6%) believed malaria is mostly transmitted during the dry season. Fewer children (21.2%) had a history of malaria in the last 3 months. Conclusions: The risk of malaria transmission was low among OVC. Continuous accessibility of orphanage homes to LLINs should be sustained to prevent malaria transmission among OVC.

Malaria in migrant agricultural workers in western Ethiopia: entomological assessment of malaria transmission risk

BackgroundEthiopia has made great strides in malaria control over the last two decades. However, this progress has not been uniform and one concern has been reported high rates of malaria transmission in large agricultural development areas in western Ethiopia. Improved vector control is one way this transmission might be addressed, but little is known about malaria vectors in this part of the country.MethodsTo better understand the vector species involved in malaria transmission and their behaviour, human landing collections were conducted in Dangur woreda, Benishangul-Gumuz, between July and December 2017. This period encompasses the months with the highest rain and the peak mosquito population. Mosquitoes were identified to species and tested for the presence of Plasmodium sporozoites.ResultsThe predominant species of the Anopheles collected was Anopheles arabiensis (1,733; i.e. 61.3 % of the entire Anopheles), which was also the only species identified with sporozoites (Plasmodium falciparum and Plasmodium vivax). Anopheles arabiensis was collected as early in the evening as 18:00 h-19:00 h, and host-seeking continued until 5:00 h-6:00 h. Nearly equal numbers were collected indoors and outdoors. The calculated entomological inoculation rate for An. arabiensis for the study period was 1.41 infectious bites per month. More An. arabiensis were collected inside and outside worker’s shelters than in fields where workers were working at night.ConclusionsAnopheles arabiensis is likely to be the primary vector of malaria in the agricultural development areas studied. High rates of human biting took place inside and outdoor near workers’ residential housing. Improved and targeted vector control in this area might considerably reduce malaria transmission.

Multi-Indicator and Multistep Assessment of Malaria Transmission Risks in Western Kenya.

Malaria risk factor assessment is a critical step in determining cost-effective intervention strategies and operational plans in a regional setting. We develop a multi-indicator multistep approach to model the malaria risks at the population level in western Kenya. We used a combination of cross-sectional seasonal malaria infection prevalence, vector density, and cohort surveillance of malaria incidence at the village level to classify villages into malaria risk groups through unsupervised classification. Generalized boosted multinomial logistics regression analysis was performed to determine village-level risk factors using environmental, biological, socioeconomic, and climatic features. Thirty-six villages in western Kenya were first classified into two to five operational groups based on different combinations of malaria risk indicators. Risk assessment indicated that altitude accounted for 45-65% of all importance value relative to all other factors; all other variable importance values were < 6% in all models. After adjusting by altitude, villages were classified into three groups within distinct geographic areas regardless of the combination of risk indicators. Risk analysis based on altitude-adjusted classification indicated that factors related to larval habitat abundance accounted for 63% of all importance value, followed by geographic features related to the ponding effect (17%), vegetation cover or greenness (15%), and the number of bed nets combined with February temperature (5%). These results suggest that altitude is the intrinsic factor in determining malaria transmission risk in western Kenya. Malaria vector larval habitat management, such as habitat reduction and larviciding, may be an important supplement to the current first-line vector control tools in the study area.

Prevalence of simian malaria parasites in macaques of Singapore.

Plasmodium knowlesi is a simian malaria parasite currently recognized as the fifth causative agent of human malaria. Recently, naturally acquired P. cynomolgi infection in humans was also detected in Southeast Asia. The main reservoir of both parasites is the long-tailed and pig-tailed macaques, which are indigenous in this region. Due to increased urbanization and changes in land use, there has been greater proximity and interaction between the long-tailed macaques and the general population in Singapore. As such, this study aims to determine the prevalence of simian malaria parasites in local macaques to assess the risk of zoonosis to the general human population. Screening for the presence of malaria parasites was conducted on blood samples from 660 peridomestic macaques collected between Jan 2008 and Mar 2017, and 379 wild macaques collected between Mar 2009 and Mar 2017, using a Pan-Plasmodium-genus specific PCR. Positive samples were then screened using a simian Plasmodium species-specific nested PCR assay to identify the species of parasites (P. knowlesi, P. coatneyi, P. fieldi, P. cynomolgi, and P. inui) present. All the peridomestic macaques sampled were tested negative for malaria, while 80.5% of the 379 wild macaques were infected. All five simian Plasmodium species were detected; P. cynomolgi being the most prevalent (71.5%), followed by P. knowlesi (47.5%), P. inui (42.0%), P. fieldi (32.5%), and P. coatneyi (28.5%). Co-infection with multiple species of Plasmodium parasites was also observed. The study revealed that Singapore’s wild long-tailed macaques are natural hosts of the five simian malaria parasite species, while no malaria was detected in all peridomestic macaques tested. Therefore, the risk of simian malaria transmission to the general human population is concluded to be low. However, this can be better demonstrated with the incrimination of the vectors of simian malaria parasites in Singapore.

Identification and characterisation of mosquitoes from different locations in Qatar in 2017-2019.

Mosquito-borne infections have considerable consequences for public health. The mere presence of a single case of vector-borne disease (VBD) introduces a risk to the local community particularly when associated with the compatible vector, host, and suitable environmental factors. Presently, there is no well-established vector control and surveillance programme in Qatar; therefore, the likelihood of VBDs spreading is undetermined. As a result, there is a pressing need to address this gap and enable successful management of VBDs. This study presents the results of three consecutive field surveys conducted between 2017 and 2019 with the aim of defining the types and distribution of mosquitoes that are of public health importance in Qatar. The results of the adult mosquito trappings show that the southern house mosquito Culex quinquefasciatus is the most widespread and abundant mosquito species, followed by Cx. perexiguus, both species representing a risk of West Nile virus transmission. All sampling methods show that the malaria vector Anopheles stephensi is widespread including in urbanised areas, suggesting a risk of local malaria transmission. The wetland mosquito Aedes caspius is also widespread, representing a risk of Rift Valley fever virus transmission. The dengue vector Ae. aegypti was not detected and can be considered neither widespread nor abundant, suggesting a minimal risk for local transmission of dengue, chikungunya and Zika viruses. Interestingly, the study detected Culiseta longiareolata for the first time in Qatar. Regular field studies are needed to further address the knowledge gaps in terms of distribution, ecology, and biting habits of different mosquito species currently present in Qatar to accurately assess the risk of mosquito-borne diseases.

Preliminary validation of the use of IgG antibody response to Anopheles gSG6-p1 salivary peptide to assess human exposure to malaria vector bites in two endemic areas of Cameroon in Central Africa.

The specific immune response to the Anopheles salivary peptide could be a pertinent and complementary tool to assess the risk of malaria transmission and the effectiveness of vector control strategies. This study aimed to obtain first reliable data on the current state of the Anopheles gSG6-P1 biomarker for assess the level of exposure to Anopheles bites in high malaria endemic areas in Cameroon. Blood smears were collected from people living in the neighborhoods of Youpwe (suburban area, continental) and Manoka (rural area, Island), both areas in the coastal region of Cameroon. Malaria infection was determined using thick blood smear microscopy, whereas the level of specific IgG response to gSG-P1 peptide was assessed by enzyme-linked immunosorbent assay from the dried blood spots. Of 266 (153 from Youpwe, 113 from Manoka) malaria endemic residents (mean age: 22.8±19.8 years, age range: 6 months–94 years, male/female sex ratio: 1/1.2, with Manoka mean age: 23.71±20.53, male/female sex ratio:1/1.13 and Youpwe mean age: 22.12±19.22, male/female sex ratio 1/0.67) randomly included in the study, Plasmodium infection prevalence was significantly higher in Manoka than in Youpwe (64.6% vs 12,4%, p = 0.0001). The anti-gSG6-P1 IgG response showed a high inter-individual heterogeneity and was significantly higher among individuals from Manoka than those from Youpwe (p = 0.023). Malaria infected individuals presented a higher anti-gSG6-P1 IgG antibody response than non-infected (p = 0.0004). No significant difference in the level of specific IgG response to gSG-P1 was observed according to long lasting insecticidal nets use. Taken together, the data revealed that human IgG antibody response to Anopheles gSG-P1 salivary peptide could be also used to assess human exposure to malaria vectors in Central African region. This finding strengthens the relevance of this candidate biomarker to be used for measuring human exposure to malaria vectors worldwide.

Malaria vector species composition and entomological indices following indoor residual spraying in regions bordering Lake Victoria, Tanzania

BackgroundVector control through long-lasting insecticidal nets (LLINs) and focal indoor residual spraying (IRS) is a major component of the Tanzania national malaria control strategy. In mainland Tanzania, IRS has been conducted annually around Lake Victoria basin since 2007. Due to pyrethroid resistance in malaria vectors, use of pyrethroids for IRS was phased out and from 2014 to 2017 pirimiphos-methyl (Actellic® 300CS) was sprayed in regions of Kagera, Geita, Mwanza, and Mara. Entomological surveillance was conducted in 10 sprayed and 4 unsprayed sites to determine the impact of IRS on entomological indices related to malaria transmission risk.MethodsWHO cone bioassays were conducted monthly on interior house walls to determine residual efficacy of pirimiphos-methyl CS. Indoor CDC light traps with or without bottle rotator were hung next to protected sleepers indoors and also set outdoors (unbaited) as a proxy measure for indoor and outdoor biting rate and time of biting. Prokopack aspirators were used indoors to capture resting malaria vectors. A sub-sample of Anopheles was tested by PCR to determine species identity and ELISA for sporozoite rate.ResultsAnnual IRS with Actellic® 300CS from 2015 to 2017 was effective on sprayed walls for a mean of 7 months in cone bioassay. PCR of 2016 and 2017 samples showed vector populations were predominantly Anopheles arabiensis (58.1%, n = 4,403 IRS sites, 58%, n = 2,441 unsprayed sites). There was a greater proportion of Anopheles funestus sensu stricto in unsprayed sites (20.4%, n = 858) than in sprayed sites (7.9%, n = 595) and fewer Anopheles parensis (2%, n = 85 unsprayed, 7.8%, n = 591 sprayed). Biting peaks of Anopheles gambiae sensu lato (s.l.) followed periods of rainfall occurring between October and April, but were generally lower in sprayed sites than unsprayed. In most sprayed sites, An. gambiae s.l. indoor densities increased between January and February, i.e., 10–12 months after IRS. The predominant species An. arabiensis had a sporozoite rate in 2017 of 2.0% (95% CI 1.4–2.9) in unsprayed sites compared to 0.8% (95% CI 0.5–1.3) in sprayed sites (p = 0.003). Sporozoite rates were also lower for An. funestus collected in sprayed sites.ConclusionThis study contributes to the understanding of malaria vector species composition, behaviour and transmission risk following IRS around Lake Victoria and can be used to guide malaria vector control strategies in Tanzania.

Threshold and stability results in a periodic model for malaria transmission with partial immunity in humans

We develop a periodic compartmental population model for the spread of malaria, dividing the human population into two classes: non-immune and semi-immune. The effect of seasonal changes in weather on the malaria transmission is considered by applying a non-autonomous model where mosquito birth, death and biting rates are time-dependent. We show that the global dynamics of the system is determined by the basic reproduction number, which we define as the spectral radius of a linear integral operator. For values of the basic reproduction number less than unity, the disease-free periodic solution is globally asymptotically stable, while if R0>1, then the disease remains endemic in the population. We show simulations in accordance with the analytic results. Finally, we show that the time-average reproduction rate gives an underestimation for malaria transmission risk.

Housing quality improvement is associated with malaria transmission reduction in Costa Rica

Housing quality has been identified as a key factor for malaria transmission risk. Here, we study the macroecological association between housing quality, measured by construction materials, and water access with malaria transmission at the county level in Costa Rica. We used SCAN cluster analysis to identify spatio-temporal clusters of malaria transmission using county level annual malaria records from 1976 to 2018. Data on housing materials and water access collected in the 1973, 1984, 2000 and 2011 national population censuses were analyzed using principal component analysis to derive housing quality and water access indices at the county level. Negative binomial rate generalized linear models, and Akaike Information Criterion (AIC) based model selection, were used to study the association between malaria cases and the percent of houses with metallic roofs, housing quality and water access indices. We found that Malaria was clustered in southern Huétar Caribe Region (Relative Risk, RR = 62.61 for 1990–2008), Huétar Norte Region (RR = 13.73, for 1991–2000) and Puntarenas county (RR = 5.77, for 1995–2002). From 1984 to 2011 most of the counties where malaria was clustered were in the lowest 20th percentile of housing quality in Costa Rica. The regression analysis showed that malaria cases significantly decreased with increasing housing quality at rates that accelerated through time. Our results suggest that housing quality improvement is one among several factors that led Costa Rica to the malaria pre-elimination stage. We propose that housing quality improvement should be considered a component of long-term policies aiming to reduce, or eliminate, major vector-borne and other neglected tropical diseases from Costa Rica, regionally in Mesoamerica, and globally elsewhere.

Studying Land Cover Changes in a Malaria-Endemic Cambodian District: Considerations and Constraints

Malaria control is an evolving public health concern, especially in times of resistance to insecticides and to antimalarial drugs, as well as changing environmental conditions that are influencing its epidemiology. Most literature demonstrates an increased risk of malaria transmission in areas of active deforestation, but knowledge about the link between land cover evolution and malaria risk is still limited in some parts of the world. In this study, we discuss different methods used for analysing the interaction between deforestation and malaria, then highlight the constraints that can arise in areas where data is lacking. For instance, there is a gap in knowledge in Cambodia about components of transmission, notably missing detailed vector ecology or epidemiology data, in addition to incomplete prevalence data over time. Still, we illustrate the situation by investigating the evolution of land cover and the progression of deforestation within a malaria-endemic area of Cambodia. To do so, we investigated the area by processing high-resolution satellite imagery from 2018 (1.5 m in panchromatic mode and 6 m in multispectral mode) and produced a land use/land cover map, to complete and homogenise existing data from 1988 and from 1998 to 2008 (land use/land cover from high-resolution satellite imagery). From these classifications, we calculated different landscapes metrics to quantify evolution of deforestation, forest fragmentation and landscape diversity. Over the 30-year period, we observed that deforestation keeps expanding, as diversity and fragmentation indices globally increase. Based on these results and the available literature, we question the mechanisms that could be influencing the relationship between land cover and malaria incidence and suggest further analyses to help elucidate how deforestation can affect malaria dynamics.

Antibody Responses Against Anopheles darlingi Immunogenic Peptides in Plasmodium Infected Humans.

Introduction: Malaria is still an important vector-borne disease in the New World tropics. Despite the recent decline in malaria due to Plasmodium falciparum infection in Africa, a rise in Plasmodium infections has been detected in several low malaria transmission areas in Latin America. One of the main obstacles in the battle against malaria is the lack of innovative tools to assess malaria transmission risk, and the behavioral plasticity of one of the main malaria vectors in Latin America, Anopheles darlingi.Methods: We used human IgG antibodies against mosquito salivary gland proteins as a measure of disease risk. Whole salivary gland antigen (SGA) from Anopheles darlingi mosquitoes was used as antigen in Western blot experiments, in which a ~65 kDa protein was visualized as the main immunogenic band and sent for sequencing by mass spectrometry. Apyrase and peroxidase peptides were designed and used as antigens in an ELISA-based test to measure human IgG antibody responses in people with different clinical presentations of malaria.Results: Liquid chromatography–mass spectrometry revealed 17 proteins contained in the ~65 kDa band, with an apyrase and a peroxidase as the two most abundant proteins. Detection of IgG antibodies against salivary antigens by ELISA revealed a significant higher antibody levels in people with malaria infection when compared to uninfected volunteers using the AnDar_Apy1 and AnDar_Apy2 peptides. We also detected a significant positive correlation between the anti-peptides IgG levels and antibodies against the Plasmodium vivax and P. falciparum antigens PvMSP1 and PfMSP1. Odd ratios suggest that people with higher IgG antibodies against the apyrase peptides were up to five times more likely to have a malaria infection.Conclusion: Antibodies against salivary peptides from An. darlingi salivary gland proteins may be used as biomarkers for malaria risk.

Anopheles arabiensis and Anopheles funestus biting patterns in Dielmo, an area of low level exposure to malaria vectors

BackgroundIn Dielmo, Senegal, the widespread use of long-lasting insecticidal nets has decreased both the incidence of malaria and the density of the Anopheles population. However, persistent low-level malaria transmission may hamper efforts to eliminate the disease. Therefore, continuous monitoring of the vector population is needed in order to improve knowledge of Anopheles biting behaviour and to readjust control interventions.MethodsIn 2015, Anopheles were collected every month for a whole year and each specimen was identified using morphological and molecular techniques. The biting pattern of each species was analysed according to night (7 pm–7am) and morning (7am–11am) periods, the place of biting and the season. The ELISA CSP technique was used to assess the Plasmodium falciparum sporozoite rate to evaluate the entomological inoculation rate (EIR).ResultsAnopheles arabiensis and Anopheles funestus sensu stricto were found to be the main vectors biting humans. Overall, the biting rate was low, at 3.84bites per night (bpn) and 1.27 bites per morning (bpm), respectively (IRR = 3.04, CI [1.84–5.00], p < 0.001). The EIR was 2.51 and 5.03 infectious bites per year during the night and morning, respectively. During the night, the An. arabiensis and An. funestus biting rate was 1.81 bpn and 1.71 bpn, respectively (IRR = 0.95, CI [0.46–1.92], p = 0.88). During the morning, their density decreased to 0.51 bpm and 0.73 bpm for An. arabiensis and An. funestus, respectively (IRR = 1.47, CI [0.58–3.71], p = 0.41). During the night and the morning, no specific trend of indoor or outdoor biting was observed in the dry and rainy season for both vectors.ConclusionThis study highlighted low level Anopheles nocturnal and diurnal biting and the associated risk of malaria transmission. It showed also the influence of the season on the indoor and outdoor biting pattern, indicating that the human population could be exposed all year round to a low level of Anopheles bites. Control programmes should increase awareness of the use of bed nets throughout the year and promote the development and implementation of complimentary tools to target Anopheles biting shortly after dawn when people are still indoors and outside the bed nets.

Remote Sensing and Multi-Criteria Evaluation for Malaria Risk Mapping to Support Indoor Residual Spraying Prioritization in the Central Highlands of Madagascar

The National Malaria Control Program (NMCP) in Madagascar classifies Malagasy districts into two malaria situations: districts in the pre-elimination phase and districts in the control phase. Indoor residual spraying (IRS) is identified as the main intervention means to control malaria in the Central Highlands. However, it involves an important logistical mobilization and thus necessitates prioritization of interventions according to the magnitude of malaria risks. Our objectives were to map the malaria transmission risk and to develop a tool to support the Malagasy Ministry of Public Health (MoH) for selective IRS implementation. For the 2014–2016 period, different sources of remotely sensed data were used to update land cover information and substitute in situ climatic data. Spatial modeling was performed based on multi-criteria evaluation (MCE) to assess malaria risk. Models were mainly based on environment and climate. Three annual malaria risk maps were obtained for 2014, 2015, and 2016. Annual parasite incidence data were used to validate the results. In 2016, the validation of the model using a receiver operating characteristic (ROC) curve showed an accuracy of 0.736; 95% CI [0.669–0.803]. A free plugin for QGIS software was made available for NMCP decision makers to prioritize areas for IRS. An annual update of the model provides the basic information for decision making before each IRS campaign. In Madagascar and beyond, the availability of the free plugin for open-source software facilitates the transfer to the MoH and allows further application to other problems and contexts.

Entomological profile and new registers of the genera Anopheles (Diptera, Culicidae) in a Brazilian rural community of the District of Coxipó do Ouro, Cuiabá, Mato Grosso

The order Diptera is constituted of insects that possess numerous varieties of habitats, these winged, commonly called mosquitoes, comprise a monophyletic group. Malaria transmitters in Brazil are represented by mosquitoes of the Anopheles genus, being it principal vector species Anopheles (Nyssorhynchus) darlingi Root. Collectings were accomplished in the rural area of Cuiabá in the region of Coxipó do Ouro/MT, and a total 4,773 adult mosquitoes of the genus Anopheles were obtained. The prevailing species in the collectings where An. (Nys.) darlingi with 3,905 (81.8%), considered the vector of major epidemiological expression in the region, followed by Anopheles (Nyssorhynchus) argyritarsis (Robineau-Desvoidy) 267 (5.6%) and Anopheles (Nyssorhynchus) triannulatus (Neiva &amp; Pinto) 226 (4.7%). This report might be useful to entomological surveillance, demonstrating that the Coxipó do Ouro/MT locality might be elected as an area to be monitored, once the presence of such vector in this type of environment indicates a potential malaria transmission risk for the neighbouring regions in the state of Mato Grosso.

Shifting transmission risk for malaria in Africa with climate change: a framework for planning and intervention

BackgroundMalaria continues to be a disease of massive burden in Africa, and the public health resources targeted at surveillance, prevention, control, and intervention comprise large outlays of expense. Malaria transmission is largely constrained by the suitability of the climate for Anopheles mosquitoes and Plasmodium parasite development. Thus, as climate changes, shifts in geographic locations suitable for transmission, and differing lengths of seasons of suitability will occur, which will require changes in the types and amounts of resources.MethodsThe shifting geographic risk of malaria transmission was mapped, in context of changing seasonality (i.e. endemic to epidemic, and vice versa), and the number of people affected. A published temperature-dependent model of malaria transmission suitability was applied to continental gridded climate data for multiple future AR5 climate model projections. The resulting outcomes were aligned with programmatic needs to provide summaries at national and regional scales for the African continent. Model outcomes were combined with population projections to estimate the population at risk at three points in the future, 2030, 2050, and 2080, under two scenarios of greenhouse gas emissions (RCP4.5 and RCP8.5).ResultsEstimated geographic shifts in endemic and seasonal suitability for malaria transmission were observed across all future scenarios of climate change. The worst-case regional scenario (RCP8.5) of climate change predicted an additional 75.9 million people at risk from endemic (10-12 months) exposure to malaria transmission in Eastern and Southern Africa by the year 2080, with the greatest population at risk in Eastern Africa. Despite a predominance of reduction in season length, a net gain of 51.3 million additional people is predicted be put at some level of risk in Western Africa by midcentury.ConclusionsThis study provides an updated view of potential malaria geographic shifts in Africa under climate change for the more recent climate model projections (AR5), and a tool for aligning findings with programmatic needs at key scales for decision-makers. In describing shifting seasonality, it was possible to capture transitions between endemic and epidemic risk areas, to facilitate the planning for interventions aimed at year-round risk versus anticipatory surveillance and rapid response to potential outbreak locations.

Plasmodium Detection using Machine Learning

Plasmodium is one of India's biggest public health problems. Early prediction of a malaria epidemic is that the secret to malaria morbidity management, mortality as well as reducing the risk of malaria transmission in the community will benefit politicians, health care providers, medical officers, health ministry and other health organizations to better target medical resources to areas of greatest need. In this project, we acquire data sets from hospital databases, which have the information about the causes of malaria, and the images of cells infected with malaria. We then analyze these data sets and feed them to our machine-learning model. Here we are using contour detection and random forest algorithms for training the model and predicting the output

Determination of cut-off and correlates of delay in treatment-seeking of febrile illness: a retrospective analysis

BackgroundEarly diagnosis and treatment of malaria symptoms reduces the risk of severe complication and malaria transmission. However, delay in malaria diagnosis and treatment is a major public health problem in India. The primary aim of the study was to determine cut-off for the delay in seeking treatment of fever, and the secondary aim was to identify the factors associated with delay in malaria-endemic areas of Assam, Northeast India.MethodsThe present study analysed data from two prior cross-sectional surveys (community- and hospital-based) that was conducted to study the health-seeking behaviour of people residing in high malaria-endemic areas of Assam, Northeast India. The hospital-based survey data were used to determine optimal cut-off for the delay in reporting, and further, used to identify the factors associated with delay using community-based data.ResultsMean age of fever cases was similar in both community- and hospital-based surveys (23.1 years vs 24.2 years, p = 0.229). Delay in reporting fever was significantly higher among hospital inpatients compared to community-based fever cases (3.6 ± 2.1 vs 4.0 ± 2.6 days; p = 0.006). Delay of > 2 days showed higher predictive ability (sensitivity: 96.4%, and ROC area: 67.5%) compared to other cut-off values (> 3, > 4, and > 5 days). Multivariable logistic regression analysis revealed that the adjusted odds ratio (aOR) of delay was significantly higher for people living in rural areas (1.52, 95%CI: 1.11–2.09), distance (> 5 km) to health facility (1.93, 95%CI: 1.44–2.61), engaged in agriculture work (2.58, 95%CI: 1.97–3.37), and interaction effect of adult male aged 20–40 years (1.71, 95%CI: 1.06–2.75).ConclusionThe delay (> 2 days) in seeking treatment was likely to be twice among those who live in rural areas and travel > 5 km to assess health care facility. The findings of the study are useful in designing effective intervention programmes for early treatment of febrile illness to control malaria.