Socio-economic determinants for malaria transmission risk in an endemic primary health centre in Assam, India

Living Conditions and Malaria: A Longitudinal Study in a Rural Malaria-Endemic Area of Sri Lanka

This study was conducted in a rural malaria-endemic community in Sri Lanka in 2014-2015 because malaria was no longer endemic in the area as of November 2012. Data on sociodemographic factors, living conditions, malaria infections, and use of mosquito protection methods during the period from 1990 to 2015 were collected through a household survey in a systematically selected sample of 724 households, covering >10% of the population in the area. Malaria incidence data were obtained from Anti-Malaria Campaign, and Malaria Research Unit of the University of Colombo. A total of 24,549 malaria cases were reported and a considerable improvement in living conditions was noted during the period covered. The association of malaria case incidence with living conditions of the community was evaluated using Spearman Rank Correlation at P <0.05. Sixty-six percent of households reported a history of malaria. The percentage of poorest type of houses (type 1) declined from 38.8% in the 1990-1994 period to 1.6% by 2015, whereas the best houses (type 5) doubled from 49.1% to 92.1% during the same period. Malaria case incidence was reported to be lowest in the best type houses (r = -0.933, P = 0.007), when pipe-borne water was available within the premises (for drinking: r = -0.846, P = 0.034; for personal hygiene: r = -0.859, P = 0.029), when water-sealed sanitary facilities were available (r = -0.956, P = 0.003), and when mosquito nets were used (r = -0.98, P = 0.001). This observed negative association may have been due to reduced human-mosquito contact.

A systematic review of the factors associated with malaria infection among forest rangers

INTRODUCTION

Malaria is a vector-borne disease that initially manifests as fever, headache, and chills. The illness could progress to more severe conditions, including lethargy, impaired consciousness, convulsions, shortness of breath, blood in urine, jaundice, and haemorrhage if left untreated. The risk of contracting malaria is considerably heightened in specific occupational settings, particularly among forest rangers, following frequent exposure to natural habitats. Consequently, advancing the understanding of malaria and emphasising how specific occupational environments (including those of forest rangers) contribute to disease risk and management is imperative.

OBJECTIVE

The present study aims to determine the factors associated with malaria infection among forest rangers by systematically reviewing electronic articles from three databases (EBSCOhost, ScienceDirect, and ResearchGate).

METHODS

The current review was prepared based on the updated preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. First, three independent reviewers screened the titles and abstracts of the data collected. The information was then stored in Endnote20 based on the inclusion and exclusion criteria. The articles were critically appraised with the mixed methods appraisal tool (MMAT) to assess their quality.

RESULT

A total of 103, 31, and 51 articles from EBSCOhost, ScienceDirect, and ResearchGate, respectively, were selected, resulting in 185 unique hits. Nevertheless, only 63 full-text publications were assessed following a rigorous selection screening, from which only five were included in the final review. The studies revealed that several factors contribute to malaria infection among forest rangers. The parameters were classified into sociodemographic, individual, and living condition-related.

CONCLUSION

A better understanding of malaria progresses and identifying its potential risk factors is essential to impact worker well-being. The findings might be utilised to improve malaria infection prevention programme implementations, hence maximising their success. Pre-employment and regular health screenings could also aid in evaluating and identifying potential risks for malaria infection among forest rangers.

Vegetation index and livestock practices as predictors of malaria transmission in Nigeria

Nigeria is the most malaria-endemic country in the world. Vegetation and livestock practices have been linked to malaria transmission but little is known about these in Nigeria. The study aimed to evaluate the influence of vegetation and livestock as predictors of malaria transmission in Nigeria. Secondary data obtained from the Nigerian Demographic and Health Survey's Geospatial Covariate Datasets Manual were used for the analysis. The survey was carried out successfully in 1389 clusters of thirty (30) households each using a two-stage stratified random sampling design. Hierarchical beta regression models were used to model the associations between malaria incidence, enhanced vegetation index (EVI), and livestock practices. The correlation coefficients for vegetation index and livestock-related variables ranged from - 0.063 to 0.074 and varied significantly with the incidence of malaria in Nigeria (P < 0.001). The model showed vegetation index, livestock goats, and sheep as positive predictors of malaria transmission. Conversely, livestock chicken and pigs were observed to reduce the risk of malaria. The study recommends the need to take into account local differences in transmission when developing malaria early warning systems that utilize environmental and livestock predictors.

Assessment of malaria prevention knowledge, attitude, and practice and associated factors among households living in rural malaria-endemic areas in the Afar Pastoral Region of Ethiopia

Background

Malaria morbidity has reduced significantly in most regions of Ethiopia, but it is still a serious issue in the northeast, particularly in the Afar region.

Objective

The study aimed to evaluate household heads' knowledge, attitudes, and practices toward malaria prevention and its associated factors in rural Ada'ar woreda district in the Afar region.

Methods

A community-based cross-sectional study was conducted among 422 households living in Ada'ar woreda district. A systematic sampling technique was used to select households. A pre-tested, structured questionnaire was used to interview randomly selected adult household heads. Frequency and percentage were computed. Logistic regression was used to determine the association between independent and dependent variables. Statistical significance was considered to be a p-value <0.05.

Results

Nearly two-thirds (64.2%) of household heads had good knowledge of malaria prevention, and 46.9% had a positive attitude toward it. About 17.3 and 56.9% of study participants had good malaria prevention practices and good healthcare seeking behaviors, respectively. Illiterate (AOR = 2.62, 95% CI: 1.49-4.63) and low-income (AOR = 2.6, 95% CI: 1.2-5.6) participants were more likely to have poor knowledge of malaria prevention (malaria signs and symptoms, malaria transmissions, and malaria prevention methods). Married participants (AOR = 2.52, 95% CI: 1.02-6.29) and illiterates (AOR = 2.83, 95% CI: 1.69-4.73) had negative attitudes toward malaria prevention. Household heads with poor knowledge of malaria prevention had 85% higher rates of practicing poor malaria prevention methods (regular bed nets used; AOR = 1.85, 95% CI: 1.2-2.8). Young adults (18-25 years) were more likely to have poor healthcare seeking behaviors (AOR = 3.5, 95% CI: 1.73-7.1), while pastoralists had a lower likelihood (AOR = 0.46, 95% CI: 0.28-0.8).

Conclusion

Knowledge, attitude, and practices toward malaria prevention remain a problem in malaria-endemic rural areas of the Afar region of Ethiopia. There is a need for the implementation of interventions that will focus on increasing knowledge of malaria prevention and encouraging positive attitudes toward it, as well as promoting regular bed net usage and healthcare seeking behaviors.

Prevalence and predictors of asymptomatic malaria infection in Boricha District, Sidama Region, Ethiopia: implications for elimination strategies

BACKGROUND

Malaria remains a major public health threat in Ethiopia despite the tremendous progress made towards the 2030 elimination targets. The silent transmission of asymptomatic infection is one of the factors that enhance the persistence of the disease as a public health issue and impedes efforts to eliminate malaria. Thus, this study aimed at investigating the prevalence and risk factors of asymptomatic malaria infection in Boricha district, Sidama region of Ethiopia.

METHODS

A community-based cross-sectional study was conducted in eight selected kebeles (smallest administrative unit) in Boricha district. Representative households were chosen using a multi-stage sampling technique. A total of 573 participants were included in the study. Malaria diagnosis was performed using rapid diagnostic test (RDT) and microscopy. A structured questionnaire was administered to collect socio-demographic information. Epi data 3.1 was employed for data entry, and SPSS version 25 was used for analysis.

RESULTS

Of the 573 asymptomatic participants tested, 6.1% were found to be positive by RDT and 4.0% by microscopy. Participants aged under 5 years (AOR = 1.57, 95% CI 0.46-5.39) and 5-14 years old (AOR = 2.42, 95% CI 1.08-5.40), Insecticide-treated net utilization (AOR = 8.41; 95% CI 1.09-65.08), travel history (AOR = 6.85, 95% CI 2.32-20.26) and living in a house with windows (AOR = 2.11, 95% CI 1.02-4.36) were significantly associated with the asymptomatic malaria infection.

CONCLUSION

The findings of this study revealed that prevalence of asymptomatic malaria infection was higher in the study area. As a result, rigorous implementation of existing interventions, such as vector control and anti-malaria drugs, is strongly recommended. In addition, devising new ones that are suited to the contextual situations is highly suggested.

Impact assessment of Intensified Malaria Control Project in transitioning a high malaria-endemic district to a low-endemic district: an epidemiological aspect

Intensified Malaria Control Project (IMCP) was implemented in 2005 to control malaria in all North-Eastern and Odisha states of India. The present study aimed to investigate the impact of IMCP in reducing the malaria burden in Udalguri district, Assam state of North-East India. Malaria epidemiological data were obtained for IMCP intervention (Udalguri) and nonintervention district (West Singhbhumi, Jharkhand state). IMCP activities include introducing bi-valent rapid diagnostic kits (RDTs), Artemether-Lumefantrine drug in North-East India, long-lasting insecticidal nets (LLINs) distribution, and creating awareness programs about malaria in an intensified mode. The data revealed a significant decline in annual parasite incidence (API) from 14.94 (2005) to 2.61 (2018), -37% (95%CI: -57%, -19%, p = 001) after using LLINs in 2009 and -64% (95%CI: -116%, -14%, p = 013) after the introduction of RDTs in district Udalguri. Whereas control district showed a -28% (95%CI: -63%, 6.3%, p = 0.051) decrease in API using LLINs and a 10% (95%CI: -7.6%, 28%, p = 0.122) increase after the introduction of RDTs. Plasmodium falciparum (Pf) and P. vivax (Pv) were the major malarial parasites in Udalguri. Pv-malaria was much higher (71%) than Pf-malaria (29%) during the study period. An increasing trend of Pf cases was observed in Udalguri. Udalguri and Khoirabari BPHCs showed an overall reduction of 94% (95%CI: -143%, -45%, p = 0.001) and 84% (95%CI: -126%, -39%, p = 0.003), respectively; however, only a 10% (95%CI: -65%, -41%, p = 0.360) reduction in API was observed in Orang BPHC. An overall decrease in malaria indicates the effective implementation of vector and disease control strategies in the Udalguri district.

Do climatic and socioeconomic factors explain population vulnerability to malaria? Evidence from a national survey, India

Background

Malaria remains a public health challenge across several African and South-East Asia Region countries, including India, despite making gains in malaria-related morbidity and mortality. Poor climatic and socioeconomic factors are known to increase population vulnerability to malaria. However, there is scant literature from India exploring this link using large population-based data.

Objectives

This study aims to study the role of climatic and socioeconomic factors in determining population vulnerability to malaria in India.

Materials and Methods

We used logistic regression models on a nationally representative sample of 91,207 households, obtained from the National Sample Survey Organization (69^th round), to study the determinants of household vulnerability.

Results

Households that resided in high (odds ratio [OR]: 1.876, P < 0.01) and moderately high (OR: 3.427, P < 0.01), compared to low climatically vulnerable states were at greater odds of suffering from malaria. Among households that faced the problem of mosquitoes/flies compared to the reference group, the urban households were at higher risk of suffering from malaria (OR: 8.318, P < 0.01) compared to rural households (OR: 2.951, P < 0.01). Households from the lower income quintiles, caste, poor physical condition of their houses, poor garbage management, and water stagnation around the source of drinking water, strongly predicted malaria vulnerability.

Conclusion

Household's vulnerability to malaria differed according to state climatic vulnerability level and socioeconomic factors. More efforts by integrating local endemicity, epidemiological, and entomological information about malaria transmission must be considered while designing malaria mitigation strategies for better prevention and treatment outcomes.

Climate Drivers of Malaria Transmission Seasonality and Their Relative Importance in Sub-Saharan Africa

A new database of the Entomological Inoculation Rate (EIR) was used to directly link the risk of infectious mosquito bites to climate in Sub-Saharan Africa. Applying a statistical mixed model framework to high-quality monthly EIR measurements collected from field campaigns in Sub-Saharan Africa, we analyzed the impact of rainfall and temperature seasonality on EIR seasonality and determined important climate drivers of malaria seasonality across varied climate settings in the region. We observed that seasonal malaria transmission was within a temperature window of 15°C-40°C and was sustained if average temperature was well above 15°C or below 40°C. Monthly maximum rainfall for seasonal malaria transmission did not exceed 600 in west Central Africa, and 400 mm in the Sahel, Guinea Savannah, and East Africa. Based on a multi-regression model approach, rainfall and temperature seasonality were found to be significantly associated with malaria seasonality in all parts of Sub-Saharan Africa except in west Central Africa. Topography was found to have significant influence on which climate variable is an important determinant of malaria seasonality in East Africa. Seasonal malaria transmission onset lags behind rainfall only at markedly seasonal rainfall areas such as Sahel and East Africa; elsewhere, malaria transmission is year-round. High-quality EIR measurements can usefully supplement established metrics for seasonal malaria. The study's outcome is important for the improvement and validation of weather-driven dynamical mathematical malaria models that directly simulate EIR. Our results can contribute to the development of fit-for-purpose weather-driven malaria models to support health decision-making in the fight to control or eliminate malaria in Sub-Saharan Africa.

Renal and hepatic dysfunction parameters correlate positively with gender among patients with recurrent malaria cases in Birnin Kebbi, Northwest Nigeria

Background

Simultaneous increase in transaminases and bilirubin is an indicator of hepatic dysfunction in malaria. Malaria-induced hyperbilirubinemia has been associated with acute kidney injury and pathogenesis of cerebral malaria which are significantly associated with mortality in malaria infection. This retrospective study was designed to assess the lipid profile, and hematological, renal and hepatic function data of malaria patients in Sir Yahaya Memorial hospital Birnin Kebbi from 2016 to 2020 who are 18 years and above.

Methods

The data of all patients between 2016 and 2020 who are 18 years and above were collected. Complete data of 370 subjects who met the inclusion criteria which consist of 250 malaria subjects and 120 control subjects were analyzed.

Results

The results showed that females constitute 65.2% of malaria patients with complete records while the remaining 34.8% were males. Age distribution of the patients showed that the infection was more prevalent among 26–45 years and least among 65 years and above. Anemia and thrombocytopenia were prevalent among the female malaria patients compared to the male patients. Liver and kidney function parameters analyzed correlate positively with the gender. The infected male showed higher dysfunction in liver parameters while infected female patients showed significant dysfunction in kidney function parameters and lipid profile.

Conclusions

In conclusion, to prevent the potential widespread of acute renal and hepatic failure with the attendant morbidity and mortality among malaria patients, it is recommended that liver and kidney function tests be mandated for patients with recurring malaria and those with a history of treatment failure in the endemic area to ensure early diagnosis of malarial induced kidney and liver injury among malaria patients.

Moderate Rainfall and High Humidity During the Monsoon Season, Negligence in Using Malaria Protection Methods and High Proportion of Mild Symptomatic Patients Were the Driving Forces for Upsurge of Malaria Cases in 2018 Among Tea Tribe Populations in Endemic Dolonibasti Health Sub-center, Udalguri District, Assam State, North-East India

Malaria elimination is a global priority, which India has also adopted as a target. Despite the malaria control efforts like long-lasting insecticidal nets distribution, rounds of indoor residual spray, the introduction of bi-valent rapid diagnostic tests and artemisinin combination therapy, malaria remained consistent in Dolonibasti sub-center of Orang block primary health center (BPHC) under the district Udalguri, Assam state followed by abrupt rise in cases in 2018. Therefore, we aimed to investigate the factors driving the malaria transmission in the outbreak area of Dolonibasti sub-center. Malaria epidemiological data (2008–2018) of Udalguri district and Orang BPHC was collected. The annual (2011-2018) and monthly (2013–2018) malaria and meteorological data of Dolonibasti sub-center was collected. An entomological survey, Knowledge, Attitude and Practices study among malaria cases (n = 120) from Dolonibasti was conducted. In 2018, 26.1 % (2136/ 8188) of the population of Dolonibasti were found to be malaria positive, of which 55% were adults (n = 1176). Majority of cases were from tea tribe populations (90%), either asymptomatic or with fever only, 67.5 % (81/120) had experienced malaria infection during past years. The outbreak was characterized by a strong increase in cases in June 2018, high proportion of slide falciparum rate of 26.1% (other years average, 15.8%) and high proportion of P. falciparum of 81.2 % (other years average, 84.3%). Anopheles minimus s.l. was the major vector with 28.6% positivity and high larval density in paddy fields/ drainage area. Annual relative humidity was associated with rise in malaria cases, annual parasite incidence (r_s = 0.69, 90%CI; p = 0.06) and slide positivity rate (r_s = 0.83, 95%CI; p = 0.01). Older people were less educated (r_s = −0.66; p < 0.001), had lesser knowledge about malaria cause (r_s = −0.42; χ²=21.80; p < 0.001) and prevention (r_s = −0.18; p = 0.04). Malaria control practices were followed by those having knowledge about cause of malaria (r_s = 0.36; χ² = 13.50; p < 0.001) and prevention (r_s = 0.40; χ² = 17.71; p < 0.001). Altogether, 84.6% (44/52) of the respondents did not use protective measures. We described a sudden increase in malaria incidence in a rural, predominantly tea tribe population group with high illiteracy rate and ignorance on protective measures against malaria. More efforts that are concerted needed to educate the community about malaria control practices.

Guiding placement of health facilities using multiple malaria criteria and an interactive tool

BACKGROUND

Access to healthcare is important in controlling malaria burden and, as a result, distance or travel time to health facilities is often a significant predictor in modelling malaria prevalence. Adding new health facilities may reduce overall travel time to health facilities and may decrease malaria transmission. To help guide local decision-makers as they scale up community-based accessibility, the influence of the spatial allocation of new health facilities on malaria prevalence is evaluated in Bunkpurugu-Yunyoo district in northern Ghana. A location-allocation analysis is performed to find optimal locations of new health facilities by separately minimizing three district-wide objectives: malaria prevalence, malaria incidence, and average travel time to health facilities.

METHODS

Generalized additive models was used to estimate the relationship between malaria prevalence and travel time to the nearest health facility and other geospatial covariates. The model predictions are then used to calculate the optimisation criteria for the location-allocation analysis. This analysis was performed for two scenarios: adding new health facilities to the existing ones, and a hypothetical scenario in which the community-based healthcare facilities would be allocated anew. An interactive web application was created to facilitate efficient presentation of this analysis and allow users to experiment with their choice of health facility location and optimisation criteria.

RESULTS

Using malaria prevalence and travel time as optimisation criteria, two locations that would benefit from new health facilities were identified, regardless of scenarios. Due to the non-linear relationship between malaria incidence and prevalence, the optimal locations chosen based on the incidence criterion tended to be inequitable and was different from those based on the other optimisation criteria.

CONCLUSIONS

This study findings underscore the importance of using multiple optimisation criteria in the decision-making process. This analysis and the interactive application can be repurposed for other regions and criteria, bridging the gap between science, models and decisions.

Malaria infection and anemia status in under-five children from Southern Tanzania where seasonal malaria chemoprevention is being implemented

BACKGROUND

Malaria and anemia remain major public health challenges in Tanzania. Household socioeconomic factors are known to influence these conditions. However, it is not clear how these factors influence malaria transmission and anemia in Masasi and Nanyumbu Districts. This study presents findings on malaria and anemia situation in under-five children and its influencing socioeconomic factors in Masasi and Nanyumbu Districts, surveyed as part of an ongoing seasonal malaria chemoprevention operational study.

METHODS

A community-based cross-sectional survey was conducted between August and September 2020. Finger-prick blood samples collected from children aged 3-59 months were used to test for malaria infection using malaria rapid diagnostic test (mRDT), thick smears for determination of asexual and sexual parasitemia, and thin smear for parasite speciation. Hemoglobin concentration was measured using a HemoCue spectrophotometer. A structured questionnaire was used to collect household socioeconomic information from parents/caregivers of screened children. The prevalence of malaria was the primary outcome. Chi-square tests, t-tests, and logistic regression models were used appropriately.

RESULTS

Overall mRDT-based malaria prevalence was 15.9% (373/2340), and was significantly higher in Nanyumbu (23.7% (167/705) than Masasi District (12.6% (206/1635), p<0.001. Location (Nanyumbu), no formal education, household number of people, household number of under-fives, not having a bed net, thatched roof, open/partially open eave, sand/soil floor, and low socioeconomic status were major risks for malaria infection. Some 53.9% (1196/2218) children had anemia, and the majority were in Nanyumbu (63.5% (458/705), p<0.001. Location (Nanyumbu), mRDT positive, not owning a bed net, not sleeping under bed net, open/partially open eave, thatched window, sex of the child, and age of the child were major risk factors for anemia.

CONCLUSION

Prevalence of malaria and anemia was high and was strongly associated with household socioeconomic factors. Improving household socioeconomic status is expected to reduce the prevalence of the conditions in the area.

Malaria Epidemiology Along the Indian Districts Bordering Bhutan and Implications for Malaria Elimination in the Region

It is important for malaria-endemic countries to address malaria control across international borders, and in particular to prioritize appropriate rapid diagnosis, treatment and surveillance. Bhutan and India aim to achieve malaria elimination by 2023 and 2030 respectively. Malaria elimination along the Indo-Bhutan border is of common concern. We delineated malaria epidemiology along the border to provide a blueprint for focusing malaria control efforts in key foci within this region. Epidemiological data from 2015 to 2019 were analyzed, as the most drastic reductions in malaria burden across most parts of India were witnessed in this time frame. Several areas of concern include low surveillance in most border districts, favorable climatic conditions for perennial malaria transmission, and movement of potential parasite carriers because of the porous borders. India and Bhutan need to control the importation/exportation of malaria cases. We highlight the foci of concern for which implementing tailor-made malaria control strategies may benefit both countries.

Risk Factors Analysis of Malaria Transmission at Cross-Boundaries Area in Menoreh Hills, Java, Indonesia

Background:

Risk factors of Malaria transmission at cross-boundaries area is important to be identified. This study aimed to identify the risk factors of Malaria transmission at cross-boundaries area in Menoreh Hills, Java, Indonesia.

Methods:

The design of the study was an observational study with a case-control design. Data on malaria cases and controls were obtained from the Primary Health Care in Menoreh. All malaria positive patients with clinical and laboratory examinations recorded in health services during 1 Jan 2015–31 Dec 2015. Overall, 138 cases and 138 controls were included. Several variables were collected such as altitude, night out behavior, the use of mosquito nets, nighttime bed, travel history, mosquito bite prevention activities, cattle ownership, distance to mosquito breeding site, etc. Data were obtained by structured questionnaires and observation. Data were analyzed by univariate, bivariate and multivariate

Results:

The altitude of house >500 m above sea level proved to be influential as a risk factor for Malaria (OR 3.62, 95% CI 1.61–8.16, P=0.002). Several variables were identified as a risk factor of Malaria such as the wall of the house from bamboo/wood, no insecticide and distance of house <100 m from mosquito breeding site.

Conclusion:

An awareness for the local health sector particularly to provide a recommendation for house construction to protect a community from Malaria transmission.

Risk factor of plasmodium knowlesi infection in Sabah Borneo Malaysia, 2020: A population-based case-control study

BACKGROUND

In the Malaysian state of Sabah, P. knowlesi notifications increased from 2% (59/2,741) of total malaria notifications in 2004 to 98% (2030/2,078) in 2017. There was a gap regarding P. knowlesi acquisition risk factors related to practice specifically in working age group. The main objective of this study was to identify the risk factors for acquiring P. knowlesi infection in Sabah among the working age group.

METHODS AND METHODS

This retrospective population-based case-control study was conducted in Ranau district to assess sociodemographic, behavioural and medical history risk factors using a pretested questionnaire. The data were entered and analyzed using IBM SPSS version 23. Bivariate analysis was conducted using binary logistic regression whereas multivariate analysis was conducted using multivariable logistic regression. We set a statistical significance at p-value less than or equal to 0.05.

RESULTS

A total of 266 cases and 532 controls were included in the study. Male gender (AOR = 2.71; 95% CI: 1.63-4.50), spending overnight in forest (AOR = 1.92; 95% CI: 1.20-3.06), not using mosquito repellent (AOR = 2.49; 95% CI: 1.36-4.56) and history of previous malaria infection (AOR = 49.34; 95% CI: 39.09-78.32) were found to be independent predictors of P. knowlesi infection.

CONCLUSIONS

This study showed the need to strengthen the strategies in preventing and controlling P. knowlesi infection specifically in changing the practice of spending overnight in forest and increasing the usage of personal mosquito repellent.

Socio-economic and household determinants of malaria in adults aged 45 and above: analysis of longitudinal ageing survey in India, 2017-2018

Background

Even though malaria cases have drastically come down in the last decade, malaria remains a serious public health concern in many parts of India. National Framework for Malaria Elimination in India (2016–2030) has been launched with the goal to eliminate malaria by 2030. Understanding the socio-economic and household determinants of malaria at the national level will greatly aid India’s malaria elimination efforts.

Methods

The data from Longitudinal Ageing Survey of India (LASI) Wave 1 (2017–2018) survey comprising 70,671 respondents ≥ 45 years across all the States and Union Territories were used for the analysis. Simple and multiple logistic regressions were used to obtain the unadjusted and adjusted odds ratio respectively of the socio-economic and household variables.

Results

The major socio-economic variables that increase the likelihood of malaria are caste (‘scheduled tribes’), low education levels and rural residence. The scheduled tribes have 1.8 times higher odds of malaria than the scheduled castes (AOR: 1.8; 95% CI: 1.5–2.1). Respondents with high school education (6–12 grade) (AOR: 0.7; 95% CI: 0.6–0.8) and college education (AOR: 0.5; 95% CI: 0.4–0.6) had a very low risk of malaria than those with no school years. Rural residence and occupation (agriculture and allied jobs) also increases the odds of malaria. The major housing determinants are household size (≥ 6), housing type (kutcha), use of unclean fuel, outside water source, improper sanitation (toilet facilities) and damp wall/ceiling.

Conclusions

The study has identified the major socio-economic and housing factors associated with malaria in adults aged 45 and above. In addition to vector and parasite control strategies in the tribal dominated regions of India, improving literacy and housing conditions may help India’s malaria elimination efforts.

Asymptomatic low-density Plasmodium infection during non-transmission season: a community-based cross-sectional study in two districts of North Eastern Region, India

BACKGROUND

Malaria elimination requires targeting asymptomatic and low-density Plasmodium infections that largely remain undetected. Therefore we conducted a cross-sectional study to estimate the burden of asymptomatic and low-density Plasmodium infection using conventional and molecular diagnostics.

METHODS

A total of 9118 participants, irrespective of age and sex, were screened for malaria using rapid diagnostic tests (RDTs), microscopy and polymerase chain reaction.

RESULTS

Among the participants, 707 presented with symptoms and 8411 without symptoms, of which Plasmodium was present in 15.6% (110/707) and 8.1% (681/8411), respectively. Low-density infection was found in 5.1% (145/2818) of participants and 8327 of 9118 were Plasmodium negative. Endemicity was propotional to asymptomatic infections (high endemicity 11.1% [404/3633] vs low endemicity 5.8% [277/4778]; odds ratio [OR] 2.0 [95% confidence interval {CI} 1.7 to 2.4]) but inversely related to low-density infection (high endemicity 3.7% [57/1545] vs low endemicity 6.9% [88/1273]; OR 1.9 [95% CI 1.4 to 2.7]). The spleen rate in children 2-9 y of age was 17.9% (602/3368) and the enlarged spleen index was 1.6. Children between 8 and 14 y showed higher odds for asymptomatic (adjusted OR [aOR] 1.75 [95% CI 1.4 to 2.2]) and low-density infections (aOR 0.63 [95% CI 0.4 to 1.0)] than adults.

CONCLUSIONS

The prevalence of asymptomatic and low-density Plasmodium infection undermines the usefulness of standard diagnostic tools used by health agencies. This necessitates deploying molecular tools in areas where malaria microscopy/RDTs indicate a dearth of infection.

Estimating the local spatio-temporal distribution of malaria from routine health information systems in areas of low health care access and reporting

BACKGROUND

Reliable surveillance systems are essential for identifying disease outbreaks and allocating resources to ensure universal access to diagnostics and treatment for endemic diseases. Yet, most countries with high disease burdens rely entirely on facility-based passive surveillance systems, which miss the vast majority of cases in rural settings with low access to health care. This is especially true for malaria, for which the World Health Organization estimates that routine surveillance detects only 14% of global cases. The goal of this study was to develop a novel method to obtain accurate estimates of disease spatio-temporal incidence at very local scales from routine passive surveillance, less biased by populations' financial and geographic access to care.

METHODS

We use a geographically explicit dataset with residences of the 73,022 malaria cases confirmed at health centers in the Ifanadiana District in Madagascar from 2014 to 2017. Malaria incidence was adjusted to account for underreporting due to stock-outs of rapid diagnostic tests and variable access to healthcare. A benchmark multiplier was combined with a health care utilization index obtained from statistical models of non-malaria patients. Variations to the multiplier and several strategies for pooling neighboring communities together were explored to allow for fine-tuning of the final estimates. Separate analyses were carried out for individuals of all ages and for children under five. Cross-validation criteria were developed based on overall incidence, trends in financial and geographical access to health care, and consistency with geographic distribution in a district-representative cohort. The most plausible sets of estimates were then identified based on these criteria.

RESULTS

Passive surveillance was estimated to have missed about 4 in every 5 malaria cases among all individuals and 2 out of every 3 cases among children under five. Adjusted malaria estimates were less biased by differences in populations' financial and geographic access to care. Average adjusted monthly malaria incidence was nearly four times higher during the high transmission season than during the low transmission season. By gathering patient-level data and removing systematic biases in the dataset, the spatial resolution of passive malaria surveillance was improved over ten-fold. Geographic distribution in the adjusted dataset revealed high transmission clusters in low elevation areas in the northeast and southeast of the district that were stable across seasons and transmission years.

CONCLUSIONS

Understanding local disease dynamics from routine passive surveillance data can be a key step towards achieving universal access to diagnostics and treatment. Methods presented here could be scaled-up thanks to the increasing availability of e-health disease surveillance platforms for malaria and other diseases across the developing world.

Spatial and temporal village-level prevalence of Plasmodium infection and associated risk factors in two districts of Meghalaya, India

BACKGROUND

Despite declining incidence over the past decade, malaria remains an important health burden in India. This study aimed to assess the village-level temporal patterns of Plasmodium infection in two districts of the north-eastern state of Meghalaya and evaluate risk factors that might explain these patterns.

METHODS

Primary Health Centre passive malaria case data from 2014 to 2018 were analysed to characterize village-specific annual incidence and temporal trends. Active malaria case detection was undertaken in 2018 and 2019 to detect Plasmodium infections using PCR. A questionnaire collected socio-demographic, environmental, and behavioural data, and households were spatially mapped via GPS. Adult mosquitoes were sampled at a subset of subjects' houses, and Anopheles were identified by PCR and sequencing. Risk factors for Plasmodium infection were evaluated using bivariate and multivariate logistic regression analysis, and spatial cluster analysis was undertaken.

RESULTS

The annual malaria incidence from PHC-based passive surveillance datasets in 2014-2018 was heterogenous but declining across villages in both districts. Active surveillance in 2018 enrolled 1468 individuals from 468 households (West Jaintia Hills) and 1274 individuals from 359 households (West Khasi Hills). Plasmodium falciparum prevalence per 100 people varied from 0 to 4.1% in the nine villages of West Jaintia Hills, and from 0 to 10.6% in the 12 villages of West Khasi Hills. Significant clustering of P. falciparum infections [observed = 11, expected = 2.15, Relative Risk (RR) = 12.65; p < 0.001] was observed in West Khasi Hills. A total of 13 Anopheles species were found at 53 houses in five villages, with Anopheles jeyporiensis being the most abundant. Risk of infection increased with presence of mosquitoes and electricity in the households [Odds Ratio (OR) = 1.19 and 1.11], respectively. Households with reported animals had reduced infection risk (OR = 0.91).

CONCLUSION

Malaria incidence during 2014-2018 declined in all study villages covered by the passive surveillance data, a period that includes the first widespread insecticide-treated net campaign. The survey data from 2018 revealed a significant association between Plasmodium infection and certain household characteristics. Since species of Plasmodium-competent mosquito vectors continue to be abundant, malaria resurgence remains a threat, and control efforts should continue.

Socio-economic determinants of malaria in tribal dominated Mandla district enrolled in Malaria Elimination Demonstration Project in Madhya Pradesh

Background

Malaria is known as a disease of poverty because of its dominance in poverty-stricken areas. Madhya Pradesh state in central India is one of the most vulnerable states for malaria morbidity and mortality. Socio-economic, environmental and demographic factors present challenges in malaria control and elimination. As part of the Malaria Elimination Demonstration Project in the tribal district of Mandla in Madhya Pradesh, this study was undertaken to assess the role of different social-economic factors contributing to malaria incidence.

Methods

The study was conducted in the 1233 villages of district Mandla, where 87% population resides in rural areas. The data was collected using the android based mobile application—SOCH for a period of 2 years (September 2017 to August 2019). A wealth index was computed along with analysis of the socio-economic characteristics of houses with malaria cases. Variables with significant variation in malaria cases were used in logistic regression.

Results

More than 70% of houses in Mandla are Kuccha (made of thatched roof or mud), 20% do not have any toilet facilities, and only 11% had an annual income of more than 50,000 INR, which converts to about $700 per year. Households with younger heads, male heads, more number of family members were more likely to have malaria cases. Kuccha construction, improper water supply, low household income houses were also more likely to have a malaria case and the odds doubled in houses with no toilet facilities.

Conclusion

Based on the results of the study, it has been found that there is an association between the odds of having malaria cases and different household variables such as age, gender, number of members, number of rooms, caste, type of house, toilet facilities, water supply, cattle sheds, agricultural land, income, and vector control interventions. Therefore, a better understanding of the association of various risk factors that influence the incidence of malaria is required to design and/or deploy effective policies and strategies for malaria elimination. The results of this study suggest that appropriate economic and environmental interventions even in low-income and poverty-stricken tribal areas could have huge impact on the success of the national malaria elimination goals.

Assessing the Correlation between Malaria Case Mortality Rates and Access to Health Facilities in the Malaria Region of Vhembe District, South Africa

Background

Local villages in the Vhembe district of South Africa have experienced high malaria infection rates and a high variability of malaria case mortality rates over the past 20 years. This research project sets out to determine if specific socioeconomic factors have influence on the varying malaria case mortality rates.

Methods

The study used existing malaria records of all reported malaria cases in the Vhembe district between 1998 and 2017. The data set was sampled using maximum variation sampling combined with a stratified sampling approach to select the source locations with the highest reported variations in malaria case mortality. The number of medical facilities used, distances to the medical facilities, and proximity to significant water sources were subsequently spatially and statistically analysed for potential correlations between these factors and the malaria case fatality rates of the source locations.

Results

Within the period of study, a total of 57,974 malaria infections were reported from 850 source locations across the villages and neighbourhoods. The result of the sampling methods gave 30 source locations with highest reported variations in malaria case mortality. The statistical analysis indicated a significant negative correlation between the case mortality rates and the number of medical facilities used, the number of infections reported, and the maximum and mean distances travelled to the medical facilities used. In addition, the analysis indicated a positive correlation between the minimum distances travelled to the medical facilities used and the case mortality rates. The spatial analysis supported the majority of the findings from the statistical analysis. Proximity to significant water bodies was not found to have any significant impact on case mortality rates.

Conclusion

The results suggested that malaria patients from larger communities, those who had financial or other means to consult more advanced facilities, or those with a larger variety of services had a significantly lower risk of mortality. The findings of this study could assist societies and authorities in mitigating the negative effects of malaria infections on human life expectancies through improved socioeconomic development.

Predicting Malaria Transmission Dynamics in Dangassa, Mali: A Novel Approach Using Functional Generalized Additive Models

Mali aims to reach the pre-elimination stage of malaria by the next decade. This study used functional regression models to predict the incidence of malaria as a function of past meteorological patterns to better prevent and to act proactively against impending malaria outbreaks. All data were collected over a five-year period (2012-2017) from 1400 persons who sought treatment at Dangassa's community health center. Rainfall, temperature, humidity, and wind speed variables were collected. Functional Generalized Spectral Additive Model (FGSAM), Functional Generalized Linear Model (FGLM), and Functional Generalized Kernel Additive Model (FGKAM) were used to predict malaria incidence as a function of the pattern of meteorological indicators over a continuum of the 18 weeks preceding the week of interest. Their respective outcomes were compared in terms of predictive abilities. The results showed that (1) the highest malaria incidence rate occurred in the village 10 to 12 weeks after we observed a pattern of air humidity levels >65%, combined with two or more consecutive rain episodes and a mean wind speed <1.8 m/s; (2) among the three models, the FGLM obtained the best results in terms of prediction; and (3) FGSAM was shown to be a good compromise between FGLM and FGKAM in terms of flexibility and simplicity. The models showed that some meteorological conditions may provide a basis for detection of future outbreaks of malaria. The models developed in this paper are useful for implementing preventive strategies using past meteorological and past malaria incidence.

Inference and prediction of malaria transmission dynamics using time series data

BACKGROUND

Disease surveillance systems are essential for effective disease intervention and control by monitoring disease prevalence as time series. To evaluate the severity of an epidemic, statistical methods are widely used to forecast the trend, seasonality, and the possible number of infections of a disease. However, most statistical methods are limited in revealing the underlying dynamics of disease transmission, which may be affected by various impact factors, such as environmental, meteorological, and physiological factors. In this study, we focus on investigating malaria transmission dynamics based on time series data.

METHODS

A data-driven nonlinear stochastic model is proposed to infer and predict the dynamics of malaria transmission based on the time series of prevalence data. Specifically, the dynamics of malaria transmission is modeled based on the notion of vectorial capacity (VCAP) and entomological inoculation rate (EIR). A particle Markov chain Monte Carlo (PMCMC) method is employed to estimate the model parameters. Accordingly, a one-step-ahead prediction method is proposed to project the number of future malaria infections. Finally, two case studies are carried out on the inference and prediction of Plasmodium vivax transmission in Tengchong and Longling, Yunnan province, China.

RESULTS

The results show that the trained data-driven stochastic model can well fit the historical time series of P. vivax prevalence data in both counties from 2007 to 2010. Moreover, with well-trained model parameters, the proposed one-step-ahead prediction method can achieve better performances than that of the seasonal autoregressive integrated moving average model with respect to predicting the number of future malaria infections.

CONCLUSIONS

By involving dynamically changing impact factors, the proposed data-driven model together with the PMCMC method can successfully (i) depict the dynamics of malaria transmission, and (ii) achieve accurate one-step-ahead prediction about malaria infections. Such a data-driven method has the potential to investigate malaria transmission dynamics in other malaria-endemic countries/regions.

Haematological Profile of Adults with Malaria Parasitaemia Visiting the Volta Regional Hospital, Ghana

Background

Malaria is known to cause severe health consequences due to its marked effects and alteration on the haematological parameters of infected individuals. This study evaluated the haematological profile of adult individuals infected with the malaria parasite.

Methods

A retrospective study was conducted using archived data of malaria positive cases from January 2017 to March 15, 2019. Data retrieved included subjects' demographics, malaria parasite count, malaria parasite species, and full blood count parameters. A total of 236 malaria positive subjects were included in the study.

Results

The study showed that more females were infected with the malaria parasite than males (69.07% and 30.93%, respectively). A total of 87.3% of the study population were infected with Plasmodium falciparum as compared to 12.7% infected with Plasmodium malariae. The commonest haematological abnormalities that were seen in this study were lymphopenia (56.78%), anaemia (55.51%), thrombocytopenia (47.46%), eosinopenia (45.76%), neutropenia (29.24%), monocytosis (21.19%), and leucocytosis (17.37%) in the infected subjects. The mean platelet count of P. falciparum-infected subjects was decreased as compared to the mean platelet count of P. malariae-infected subjects. There was a significant (P value <0.05) decrease in the number of platelet count with every unit increase in parasite density.

Conclusion

Study participants infected with malaria demonstrated vital changes in haematological parameters with anaemia, thrombocytopenia, lymphopenia, monocytosis, and eosinopenia being the most important predictors of malaria infection especially with P. falciparum species.P. falciparum-infected subjects was decreased as compared to the mean platelet count of.

Childhood malaria case incidence in Malawi between 2004 and 2017: spatio-temporal modelling of climate and non-climate factors

BACKGROUND

Malaria transmission is influenced by a complex interplay of factors including climate, socio-economic, environmental factors and interventions. Malaria control efforts across Africa have shown a mixed impact. Climate driven factors may play an increasing role with climate change. Efforts to strengthen routine facility-based monthly malaria data collection across Africa create an increasingly valuable data source to interpret burden trends and monitor control programme progress. A better understanding of the association with other climatic and non-climatic drivers of malaria incidence over time and space may help guide and interpret the impact of interventions.

METHODS

Routine monthly paediatric outpatient clinical malaria case data were compiled from 27 districts in Malawi between 2004 and 2017, and analysed in combination with data on climatic, environmental, socio-economic and interventional factors and district level population estimates. A spatio-temporal generalized linear mixed model was fitted using Bayesian inference, in order to quantify the strength of association of the various risk factors with district-level variation in clinical malaria rates in Malawi, and visualized using maps.

RESULTS

Between 2004 and 2017 reported childhood clinical malaria case rates showed a slight increase, from 50 to 53 cases per 1000 population, with considerable variation across the country between climatic zones. Climatic and environmental factors, including average monthly air temperature and rainfall anomalies, normalized difference vegetative index (NDVI) and RDT use for diagnosis showed a significant relationship with malaria incidence. Temperature in the current month and in each of the 3 months prior showed a significant relationship with the disease incidence unlike rainfall anomaly which was associated with malaria incidence at only three months prior. Estimated risk maps show relatively high risk along the lake and Shire valley regions of Malawi.

CONCLUSION

The modelling approach can identify locations likely to have unusually high or low risk of malaria incidence across Malawi, and distinguishes between contributions to risk that can be explained by measured risk-factors and unexplained residual spatial variation. Also, spatial statistical methods applied to readily available routine data provides an alternative information source that can supplement survey data in policy development and implementation to direct surveillance and intervention efforts.

Prevalence of malaria and its risk factors in Sabah, Malaysia

OBJECTIVES

The aim of this study was to determine the prevalence of malaria in Sabah and its potential risk factors.

METHODS

This cross-sectional study analysed secondary data obtained from the health clinics in Sabah, Malaysia from January to August 2016. The Pearson Chi-square test was used to analyse the relationships between malaria infection and socio-demographic characteristics. Multivariable logistic regression was performed in order to determine the risk factors for malaria in Sabah.

RESULTS

Out of 1222 patients, 410 (33.6%) had a laboratory-confirmed malaria infection. Infection by Plasmodium knowlesi accounted for the majority of malaria reports in Sabah (n=340, 82.9%). Multivariable analysis indicated that males (prevalence odds ratio 0.023, 95% confidence interval 0.012-0.047) and those living in a rural area (prevalence odds ratio 0.004, 95% confidence interval 0.002-0.009) were at higher risk 24.0-95.9) and those living in a rural area (adjusted odds ratio 212.6, 95% confidence interval 105.8-427.2) were at higher risk of acquiring a malaria infection.

CONCLUSIONS

Malaria infections in Sabah, Malaysia are common, with P. knowlesi being the most common malaria parasite. The infection was associated with several socio-demographic and geographical factors. Thus, mitigation measures should be considered to address modifiable risk factors for malaria infection.

Intervention on malaria awareness among 'Bedia' tribal community in West Bengal, India

Background:

Tribals have a vulnerable health status because of malarial morbidities, yet they ignore their illnesses and do not go to physicians during sickness for several reasons including poverty.

Objective:

This qualitative research project attempted to create awareness among ‘Bedia’ tribal to initiate preventive and other personal protective measures against malaria.

Methods:

Initially, efforts were made to create malaria awareness by literate ‘Bedia’ volunteers who were trained to do so; however, their tribal fellows were reluctant to receive awareness efforts from them. After thorough analysis and interaction, a novel “interprofessional team” of composer, vocalist, and instrumentalists approach was made to impart malaria awareness by composing songs in the language of the aborigine. Then health education was imparted to the ‘Bedia’ participants by the trained ‘Bedia’ through theme songs with their rustic music instruments and group dance performances in the intermingled media from the team. An evaluation was done to assess usefulness of the health education intervention by the researchers.

Results:

Overall, 137 adult ‘Bedias’ in 42 families (M = 74; F = 63) participated in our study. In the informal feedback session, only 51 adult males and 46 adult females could furnish expected results. Out of the 42 families residing in the village, 11 houses consistently used mosquito bed nets before the awareness program; after the awareness program, it became 15 as was demonstrated by using social mapping.

Conclusions:

Our project activities on the Bedia tribes could unearth required interventions of awareness about malaria. However, it was possible to create awareness and confidence among them so that they could themselves take necessary preventive measures and positive approaches toward malaria.

Geo-visual integration of health outcomes and risk factors using excess risk and conditioned choropleth maps: a case study of malaria incidence and sociodemographic determinants in Ghana

Background

Recently, exploratory spatial data analysis is for problem solving, hypothesis generation and knowledge construction. Unless geographically weighted regression, sophisticated spatial regression models best control spatial heterogeneity in outcomes and the associated risk factors but cannot visually display and identify areas of the significant associations. The under-utilised excess risk maps (ERMs) and conditioned choropleth maps (CCMs) are useful to address this issue and simplify epidemiological information to public health stakeholders without much statistical backgrounds. Using malaria and sociodemographic determinants in Ghana as case study, this paper applied ERM and CCM techniques for identification of areas at elevated risk of disease-risk factor co-location.

Method

We computed and smoothed mean district-specific malaria incidences for the period 2010 to 2014 as a function of sociodemographic determinants. The spatial distribution of malaria was investigated through global and local spatial autocorrelations, and the association with sociodemographic risk factors evaluated with bivariate correlations. ERMs and CCMs were produced for the statistically significant risk factors.

Results

The incidence of malaria increased over time with cluster locations detected, predominantly at the northern parts but later few spread to the middle parts of the country. Our results suggested that with respect to sociodemographic determinants, district variations in malaria rates might be explained by inequalities in seven sociodemographics, including an unexpected significant negative association with non-religious affiliation. The sociodemographics had positive spatial autocorrelations, exhibited statistically significant interactions and the strongest was observed in urbanisation-basic education correlation (p< 0.01, r = +0.969). The ERMs and CCMs specifically identified locations with lower or higher than expected rates with respect to particular risk factor(s) where improving risk factor(s) such as employment-to-population ratio in rural areas, basic education could have cascade effects to reduce the expected malaria incidence in endemic areas.

Conclusion

Ghana remains malaria hyperendemic region with district-level spatial heterogeneity. Significant association between malaria and sociodemographics was detected and the ERMs and CCMs geo-visually pinpointed locations of these significant associations. To complement sophisticated spatial regression models, the easily interpretable ERMs and CCMs could be used to specify where disease-risk factor associations are significant, simplifying complex spatial epidemiological information for efficient public health administration.

Individual and contextual factors predicting self-reported malaria among adults in eastern Indonesia: findings from Indonesian community-based survey

BACKGROUND

Malaria is still an important parasitic infectious disease that affecting poor and vulnerable communities in many developing countries, including Indonesia. During the period of 2010-2017, there have been approximately 2.2 million confirmed malaria cases reported across Indonesia. This study aimed to identify individual, household and village-level factors associated with self-reported malaria among adults more than 15 years of age in Maluku, West Papua and Papua province.

METHODS

This study analysed a subset of the data from nationally representative population-based Indonesian National Basic Health Research (Riset Kesehatan Dasar) (N = 1,027,763 in 294,959 households in 33 provinces) in 2013. Total of 41,079 individuals (20,326 males and 20,753 females) aged ≥ 15 years in 19,269 households in Maluku, West Papua and Papua provinces were included. Participants were interviewed if they ever had been diagnosed and laboratory confirmed of having malaria by physician in the past 12 months. A mixed effects multilevel logistic regression models were developed to assess the associations between socio-demographical variables at individual, household and village level and self-reported malaria.

RESULTS

Individuals aged ≥ 15 years in 701 villages in Maluku (n = 11,919), West Papua (n = 8003) and Papua (n = 21,157) were analysed. In all provinces, gender distribution was equally-represented. The prevalence of self-reported malaria was 4.1% (Maluku), 12.4% (West Papua) and 18.8% (Papua). At the individual level, primary industry workers (OR 1.29, 95% CI 1.15-1.46 [Maluku]; OR 1.17, 95% CI 1.09-1.25 [Papua]) and having higher education were associated with self-reporting malaria (OR 0.67, 95% CI 0.53-0.83 [Maluku]; OR 1.27, 95% CI 1.15-1.40 [Papua]). Household level factors include having bed net and better off wealth index were associated with increased self-reporting malaria among West Papua (OR 1.21; 95% CI 1.09-1.34 and OR 1.38; 95% CI 1.17-1.65, respectively) and Papuan (OR 1.12; 95% CI 1.02-1.23 and OR 1.33; 95% CI 1.11-1.57, respectively) adults. Increased odds of self-reporting malaria was associated with time required to reach healthcare facility (OR 1.30, 95% CI 1.01-1.67 [Maluku]). Contextual village-level characteristics such as living in rural (OR 1.31, 95% CI 1.12-1.54 [Maluku]; OR 1.56, 95% CI 1.17-2.07 [West Papua]), higher community education level (OR 1.28, 95% CI 1.02-1.63 [West Papua]; OR 1.45, 95% CI 1.23-1.72 [Papua]), higher community bed net ownerships (OR 0.59 95% CI 0.45-0.77 [West Papua]) were associated with self-reported malaria.

CONCLUSIONS

Factors associated with self-reported malaria were varied between provinces suggesting locally-specific determinants were exist at individual, household and community-level. This study highlights the need for specific interventions by taking into consideration the contextual factors within the region and involving multi-sectoral collaboration between health authorities and related stakeholders (e.g., bureau of education, bureau of public works and infrastructure) to improve designs in planning and intervention strategies to succesfully eliminate malaria in Maluku and Papua.

Are malaria elimination efforts on right track? An analysis of gains achieved and challenges ahead

Background

Malaria causes significant morbidity and mortality each year. In the past few years, the global malaria cases have been declining and many endemic countries are heading towards malaria elimination. Nevertheless, reducing the number of cases seems to be easy than sustained elimination. Therefore to achieve the objective of complete elimination and maintaining the elimination status, it is necessary to assess the gains made during the recent years.

Main text

With inclining global support and World Health Organisation (WHO) efforts, the control programmes have been implemented effectively in many endemic countries. Given the aroused interest and investments into malaria elimination programmes at global level, the ambitious goal of elimination appears feasible. Sustainable interventions have played a pivotal role in malaria contraction, however drug and insecticide resistance, social, demographic, cultural and behavioural beliefs and practices, and unreformed health infrastructure could drift back the progress attained so far. Ignoring such impeding factors coupled with certain region specific factors may jeopardise our ability to abide righteous track to achieve global elimination of malaria parasite. Although support beyond the territories is important, but well managed integrated vector management approach at regional and country level using scrupulously selected area specific interventions targeting both vector and parasite along with the community involvement is necessary. A brief incline in malaria during 2016 has raised fresh perturbation on whether elimination could be achieved on time or not.

Conclusions

The intervention tools available currently can most likely reduce transmission but clearing of malaria epicentres from where the disease can flare up any time, is not possible without involving local population. Nevertheless maintaining zero malaria transmission and checks on malaria import in declared malaria free countries, and further speeding up of interventions to stop transmission in elimination countries is most desirable. Strong collaboration backed by adequate political and financial support among the countries with a common objective to eliminate malaria must be on top priority. The present review attempts to assess the progress gained in malaria elimination during the past few years and highlights some issues that could be important in successful malaria elimination.

Electronic supplementary material

The online version of this article (10.1186/s40249-019-0524-x) contains supplementary material, which is available to authorized users.

Prevalence of malaria in HIV positive and HIV negative pregnant women attending antenatal clinics in south eastern Nigeria

INTRODUCTION

Globally, malaria in pregnancy is a public health challenge. Malaria and HIV are among the two most important diseases contributing to the global health burden of our time. HIV positive pregnant women are at increased risk of all the adverse outcomes of malaria in pregnancy.

OBJECTIVE

The objective of this study was to compare malaria parasitaemia between HIV positive and HIV negative pregnant women attending antenatal clinics offering Preventing Maternal to Child Transmission (PMTCT) services in Enugu metropolis, south-eastern Nigeria.

METHODS

A descriptive cross sectional study was conducted among 200 HIV positive and 200 HIV negative pregnant women attending antenatal clinics in Enugu. Two out of five hospitals that provide PMTCT services were selected through balloting. Finger pricked blood samples were collected and thick blood films were examined for malaria parasite using giemsa expert microscopy. A structured interviewer administered questionnaire was used for data collection. Data was analysed using SPSS version 22.

RESULTS

The HIV positive pregnant women (152) (76%) and HIV negative women (137) (68.5%) studied were mostly in the age range of 25-34 years. Mean gestational age of HIV positive and HIV negative participants were 23.4±10.7 and 23.2±10.1 weeks respectively (P=0.001). The prevalence of malaria infection among HIV positive pregnant mothers was 81% (162/200) and 75% (150/200) among HIV negative pregnant women (P < 0.001). The HIV positive mothers had more moderate parasitaemia (86/200: 53.1%) compared to 43/200: 28.7% in HIV negative mothers (P<0.001). Even though more HIV positive mothers (54.5%) used insecticide treated nets ITNs during pregnancy compared to 41.5% in HIV negative mothers, moderate malaria parasitaemia was higher in HIV positive mothers. HIV positive nulliparous pregnant women had the highest rate of malaria parasitaemia (32/36: 88.9%).

CONCLUSION

Moderate malaria parasitaemia was higher among HIV positive pregnant women. All malaria preventive strategies should be intensified in pregnancy as ITNs provided little protection.

Prevalence and Predictors of Malaria in Human Immunodeficiency Virus Infected Patients in Beira, Mozambique

Co-infection between malaria and HIV has major public health implications. The aims of this study were to assess the malaria prevalence and to identify predictors of positivity to malaria Test in HIV positive patients admitted to the health center São Lucas of Beira, Mozambique. A retrospective cross-sectional study was performed from January 2016 to December 2016. Overall, 701 adult HIV patients were enrolled, positivity to malaria test was found in 232 (33.0%). These patients were found to be more frequently unemployed (76.3%), aged under 40 (72.0%), with a HIV positive partner (22.4%) and with a CD4 cell count <200 (59.9%). The following variables were predictors of malaria: age under 40 (O.R. = 1.56; 95%CI: 1.22–2.08), being unemployed (O.R. = 1.74; 95%CI: 1.24–2.21), irregularity of cotrimoxazole prophylaxis’s (O.R. = 1.42; 95%CI: 1.10–1.78), CD4 cell count <200 (O.R. = 2.01; 95%CI: 1.42–2.32) and tuberculosis comorbidity (O.R. = 1.58; 95%CI: 1.17–2.79). In conclusion, high malaria prevalence was found in HIV patients accessing the out-patients centre of São Lucas of Beira. Our findings allowed us to identify the profile of HIV patients needing more medical attention: young adults, unemployed, with a low CD4 cell count and irregularly accessing to ART and cotrimoxazole prophylaxis.

Manifestation of malaria in Mangaluru, southern India

BACKGROUND

Severe and fatal vivax malaria is increasingly reported from India. In Mangaluru, southern India, malaria is focused in urban areas and associated with importation by migrant workers. In Wenlock Hospital, the largest governmental hospital, the clinical, parasitological and biochemical characteristics of malaria patients were assessed.

METHODS

During the peak malaria season in 2015 (June to December), outpatients were interviewed and clinically assessed. Malaria was ascertained by microscopy and PCR assays, concentrations of haemoglobin, creatinine and bilirubin, as well as thrombocyte count, were determined, and severe malaria was defined according to WHO criteria.

RESULTS

Among 909 malaria patients, the vast majority was male (93%), adult (median, 26 years) and of low socio-economic status. Roughly half of them were migrants from beyond the local Karnataka state, mostly from northern and northeastern states. Vivax malaria (69.6%) predominated over mixed Plasmodium vivax-Plasmodium falciparum infection (21.3%) and falciparum malaria (9.0%). The geometric mean parasite density was 3412/µL. As compared to vivax malaria, patients with falciparum malaria had higher parasite density and more frequently showed impaired general condition, affected consciousness and splenomegaly. Also, they tended to more commonly have anaemia and increased creatinine levels, and to be hospitalized (7.3%). Mixed-species infections largely assumed an interim position. Severe malaria (3.5%) was not associated with parasite species. No fatality occurred.

CONCLUSION

In this study, uncomplicated cases of malaria predominated, with P. falciparum causing slightly more intense manifestation. Severe malaria was infrequent and fatalities absent. This contrasts with the reported pattern of manifestation in other parts of India, which requires the analysis of underlying causes.

Socioeconomic Condition and Prevalence of Malaria Fever in Pakistani Children: Findings from a Community Health Survey

OBJECTIVE

We assessed the prevalence of malarial fever and its association with demographic and socioeconomic factors in children <5 years of age.

METHODS

Using the data of Pakistan Demographic and Health Survey (PDHS), the socioeconomic condition (SEC) was assessed by using a household wealth index as a proxy indicator, generated through principal component analysis. Two-stage sampling was used for selection of households, and multilevel logistic regression analysis was performed.

RESULTS

The PDHS contains 10 935 children <5 years of age with valid information about malaria fever. In total, 36% (3930) children have malaria 2 weeks before the survey. A decreasing trend in prevalence of malaria fever was found with increasing SEC. Compared with SEC Quintile V, children of SEC Quintile I were more likely to get fever [adjusted odds ratio (AOR)=1.40 (1.15-1.69)] and of SEC Quintile II [AOR = 1.23 (1.03-1.45)].

CONCLUSION

SEC has a significant impact on the prevalence of malaria fever in the context of different regions in Pakistan.

Host genetics in malaria: lessons from mouse studies

Malaria remains a deadly parasitic disease caused by Plasmodium, claiming almost half a million lives every year. While parasite genetics and biology are often the major targets in many studies, it is becoming more evident that host genetics plays a crucial role in the outcome of the infection. Similarly, Plasmodium infections in mice also rely heavily on the genetic background of the mice, and often correlate with observations in human studies, due to their high genetic homology with humans. As such, murine models of malaria are a useful tool for understanding host responses during Plasmodium infections, as well as dissecting host-parasite interactions through various genetic manipulation techniques. Reverse genetic approach such as quantitative trait loci studies and random mutagenesis screens have been employed to discover novel host genes that affect malaria susceptibility in mouse models, while other targeted studies utilize mouse models to validate observation from human studies. Herein, we review the findings from the past and present studies on murine models of hepatic and erythrocytic stages of malaria and speculate on how the current mouse models benefit from the recent development in CRISPR/Cas9 gene editing technology.

Assessment of household ownership of bed nets in areas with and without artemisinin resistance containment measures in Myanmar

BACKGROUND

Myanmar lies in the Greater Mekong Subregion where there is artemisinin-resistant Plasmodium falciparum malaria. As the artemisinin compound is the pillar of effective antimalarial therapies, containing the spread of artemisinin resistance is a national and global priority. The use of insecticide-treated bed nets/long-lasting insecticidal nets (ITNs/LLINs) is the key intervention for ensuring the reduction of malaria transmission and the spread of resistant strains, and for eventually eliminating malaria. This study aimed at assessing household ownership of, access to, and utilization of bed nets in areas of Myanmar with and without artemisinin resistance containment measures.

METHODS

Secondary data from a nationwide community-based malaria survey conducted by the National Malaria Control Program in 2014 were analyzed. Based on evidence of artemisinin resistance, Myanmar was divided into tiers 1, 2, and 3: townships in tiers 1 and 2 were aggregated as the Myanmar Artemisinin Resistance Containment (MARC) areas and were compared with tier 3 townships, which were defined as non-MARC areas. The chi-square test was used to compare groups, and the level of significance was set at P ≤ 0.05.

RESULTS

Of the 6328 households assessed, 97.2% in both MARC and non-MARC areas had at least one bed net (any type), but only 63% of households had ITNs/LLINs. Only 44% of households in MARC areas and 24% in non-MARC areas had adequate numbers of ITNs/LLINs (one ITN/LLIN per two persons, P <  0.001). Nearly 44% of household members had access to ITNs/LLINs. Regarding the utilization of ITNs/LLINs, 45% of household members used them in MARC areas and 36% used them in non-MARC areas (P <  0.001, desired target = 100%). Utilization of ITNs/LLINs among children aged below five years and pregnant women (high malaria risk groups) was low, at 44% and 42%, respectively.

CONCLUSIONS

This study highlights the nationwide shortfalls in the ownership of, access to, and utilization of ITNs/LLINs in Myanmar, which is of particular concern in terms of containing the spread of artemisinin resistance. It highlights the need for priority attention to be paid and mobilization of resources in order to improve bed net coverage and utilization through bed net distribution and/or social marketing, information dissemination, and awareness-raising.

Molecular characterization of Plasmodium falciparum in Arunachal Pradesh from Northeast India based on merozoite surface protein 1 & glutamate-rich protein

Background & objectives:

Northeast (NE) India is one of the high endemic regions for malaria with a preponderance of Plasmodium falciparum, resulting in high morbidity and mortality. The P. falciparum parasite of this region showed high polymorphism in drug-resistant molecular biomarkers. However, there is a paucity of information related to merozoite surface protein 1 (msp-1) and glutamate-rich protein (glurp) which have been extensively studied in various parts of the world. The present study was, therefore, aimed at investigating the genetic diversity of P. falciparum based on msp-1 and glurp in Arunachal Pradesh, a State in NE India.

Methods:

Two hundred and forty nine patients with fever were screened for malaria, of whom 75 were positive for P. falciparum. Blood samples were collected from each microscopically confirmed patient. The DNA was extracted; nested polymerase chain reaction and sequencing were performed to study the genetic diversity of msp-1 (block 2) and glurp.

Results:

The block 2 of msp-1 gene was found to be highly polymorphic, and overall allelic distribution showed that RO33 was the dominant allele (63%), followed by MAD20 (29%) and K1 (8%) alleles. However, an extensive diversity (9 alleles and 4 genotypes) and 6-10 repeat regions exclusively of R2 type were observed in glurp.

Interpretation & conclusions:

The P. falciparum population of NE India was diverse which might be responsible for higher plasticity leading to the survival of the parasite and in turn to the higher endemicity of falciparum malaria of this region.

The contribution of malaria control interventions on spatio-temporal changes of parasitaemia risk in Uganda during 2009-2014

BACKGROUND

In Uganda, malaria vector control interventions and case management with Artemisinin Combination Therapies (ACTs) have been scaled up over the last few years as a result of increased funding. Data on parasitaemia prevalence among children less than 5 years old and coverage of interventions was collected during the first two Malaria Indicator Surveys (MIS) conducted in 2009 and 2014, respectively. In this study, we quantify the effects of control interventions on parasitaemia risk changes between the two MIS in a spatio-temporal analysis.

METHODS

Bayesian geostatistical and temporal models were fitted on the MIS data of 2009 and 2014. The models took into account geographical misalignment in the locations of the two surveys and adjusted for climatic changes and socio-economic differentials. Parasitaemia risk was predicted over a 2 × 2 km2 grid and the number of infected children less than 5 years old was estimated. Geostatistical variable selection was applied to identify the most important ITN coverage indicators. A spatially varying coefficient model was used to estimate intervention effects at sub-national level.

RESULTS

The coverage of Insecticide Treated Nets (ITNs) and ACTs more than doubled at country and sub-national levels during the period 2009-2014. The coverage of Indoor Residual Spraying (IRS) remained static at all levels. ITNs, IRS, and ACTs were associated with a reduction in parasitaemia odds of 19% (95% BCI: 18-29%), 78% (95% BCI: 67-84%), and 34% (95% BCI: 28-66%), respectively. Intervention effects varied with region. Higher socio-economic status and living in urban areas were associated with parasitaemia odds reduction of 46% (95% BCI: 0.51-0.57) and 57% (95% BCI: 0.40-0.53), respectively. The probability of parasitaemia risk decline in the country was 85% and varied from 70% in the North-East region to 100% in Kampala region. The estimated number of children infected with malaria declined from 2,480,373 in 2009 to 825,636 in 2014.

CONCLUSIONS

Interventions have had a strong effect on the decline of parasitaemia risk in Uganda during 2009-2014, albeit with varying magnitude in the regions. This success should be sustained by optimizing ITN coverage to achieve universal coverage.

Principal component analysis of socioeconomic factors and their association with malaria and arbovirus risk in Tanzania: a sensitivity analysis

Principal component analysis (PCA) is frequently adopted for creating socioeconomic proxies in order to investigate the independent effects of wealth on disease status. The guidelines and methods for the creation of these proxies are well described and validated. The Demographic and Health Survey, World Health Survey and the Living Standards Measurement Survey are examples of large data sets that use PCA to create wealth indices particularly in low and middle-income countries (LMIC), where quantifying wealth-disease associations is problematic due to the unavailability of reliable income and expenditure data. However, the application of this method to smaller survey data sets, especially in rural LMIC settings, is less rigorously studied.In this paper, we aimed to highlight some of these issues by investigating the association of derived wealth indices using PCA on risk of vector-borne disease infection in Tanzania focusing on malaria and key arboviruses (ie, dengue and chikungunya). We demonstrated that indices consisting of subsets of socioeconomic indicators provided the least methodologically flawed representations of household wealth compared with an index that combined all socioeconomic variables. These results suggest that the choice of the socioeconomic indicators included in a wealth proxy can influence the relative position of households in the overall wealth hierarchy, and subsequently the strength of disease associations. This can, therefore, influence future resource planning activities and should be considered among investigators who use a PCA-derived wealth index based on community-level survey data to influence programme or policy decisions in rural LMIC settings.

Disappearance of Anopheles minimus and Anopheles dirus from Certain Malaria Endemic Areas of Assam, India

BACKGROUND

Orang Primary Health Centre (OPHC) and Balipara Primary Health Centre (BPHC) of Assam (India) report mosquito borne diseases annually. Current study was performed to ascertain the prevalence of known malaria and Japanese Encephalitis (JE) vectors and their possible role in disease transmission.

METHODS

Malaria epidemiological data for 2006-2010 and JE data for 2008-2013 of Assam, India were obtained from the health authority. Mosquitoes were collected using CDC light traps and identified morpho-taxonomically.

RESULTS

Plasmodium falciparum cases (81.5%, 95% CI= 72.0-91.1) were statistically higher in OPHC (P< 0.0001, t= 8.0) during the recent years. There was 4.4 folds rise in the confirmed acute encephalitis syndrome (AES) and 3.2 folds increase in the confirmed JE cases during 2013 as compared to 2008. Altogether 9,218 mosquito specimens (PTND= 153.6), comprising of 44.1% anophelines (PTND= 67.7), 42.3% culicines (PTND= 65.0) and 9.5% mansonia (PTND= 14.6) were recorded. In BPHC, Anopheles vagus was recorded in high density (P< 0.0001), whereas Culex quinquefasciatus was the predominant JE vector (P= 0.04). In OPHC, among the known malaria vectors, the density of Anopheles annularis was significantly high (P< 0.0001). However Culex bitaeniorhynchus was the predominant known JE vector (P< 0.0001) followed by Cx. quinquefasciatus.

CONCLUSION

Even in the absence of known efficient vectors, many Anopheles species are still involved in malaria transmission. There was disappearance of Anopheles minimus and Anopheles dirus and establishment of An. annularis, An. vagus and An. philippinensis/nivipes mosquitoes in study area.

Malaria elimination in India and regional implications

The malaria situation in India is complex as a result of diverse socio-environmental conditions. India contributes a substantial burden of malaria outside sub-Saharan Africa, with the third highest Plasmodium vivax prevalence in the world. Successful malaria control in India is likely to enhance malaria elimination efforts in the region. Despite modest gains, there are many challenges for malaria elimination in India, including: varied patterns of malaria transmission in different parts of the country demanding area-specific control measures; intense malaria transmission fuelled by favourable climatic and environment factors; varying degrees of insecticide resistance of vectors; antimalarial drug resistance; a weak surveillance system; and poor national coordination of state programmes. Prevention and protection against malaria are low as a result of a weak health-care system, as well as financial and socioeconomic constraints. Additionally, the open borders of India provide a potential route of entry for artesunate-resistant parasites from southeast Asia. This situation calls for urgent dialogue around tackling malaria across borders-between India's states and neighbouring countries-through sharing of information and coordinated control and preventive measures, if we are to achieve the aim of malaria elimination in the region.

Major parasitic diseases of poverty in mainland China: perspectives for better control

Significant progress has been made in the prevention, control, and elimination of human parasitic diseases in China in the past 60 years. However, parasitic diseases of poverty remain major causes of morbidity and mortality, and inflict enormous economic costs on societies.In this article, we review the prevalence rates, geographical distributions, epidemic characteristics, risk factors, and clinical manifestations of parasitic diseases of poverty listed in the first issue of the journal Infectious Diseases of Poverty on 25 October 2012. We also address the challenges facing control of parasitic diseases of poverty and provide suggestions for better control.

Public awareness of malaria in the middle stage of national malaria elimination programme. A cross-sectional survey in rural areas of malaria-endemic counties, China

BACKGROUND

Remarkable progress in the elimination of malaria has been achieved by the Chinese government in the past 5 years. However, imported cases have increased rapidly, and it is a critical threat to the national malaria elimination programme. This study aims to investigate the current status of the public awareness of malaria in the middle stage of the national malaria elimination progress.

METHODS

A cross-sectional survey with multi-stage stratified randomized sampling was undertaken between June 2015 and March 2016. A total of 1321 residents from nine malaria-endemic counties, 27 townships and 81 villages were interviewed using a structured questionnaire.

RESULTS

The results showed 51.6 % of the respondents had sufficient malaria knowledge. The malaria awareness of the public in type I counties was better than that in type II, whereas that in type III was the lowest. Approximately 74.9 % of the respondents were aware of at least one form of prevention of malaria, and 85.2 % of them would seek treatment when suffering from malaria. However, the awareness of fever, chills, sweating as common symptoms of malaria were 53.4, 56.2 and 31.6 %, respectively. The level of malaria awareness of the at-risk population was similar to that of the general population, it seemingly increased along with age and declined with the distance away from township hospitals.

CONCLUSION

The public awareness of malaria needs to improve continuously. Health education campaigns should focus on basic malaria knowledge and cover target populations. The multi-sectoral or even international collaboration should be further intensified. Careful planning is required to ensure that scattered villages are incorporated into the malaria health promotion system to sustain elimination.

Determination of demographic, epidemiological, and socio-economic determinants and their potential impact on malaria transmission in Mannar and Trincomalee districts of Sri Lanka

Background

Malaria was an endemic problem in Mannar and Trincomalee districts of Sri Lanka until the recent past. Currently, no local case has been found since October 2012. Therefore, the present study was conducted to identify existing demographic, epidemiological and socio-cultural factors in Mannar and Trincomalee districts of Sri Lanka, since there is limited information available on the potential influence of above variables responsible for low malaria transmission.

Methods

An analytical cross-sectional survey was carried out on selected demographic, epidemiological and socio-economic variables in 32 localities under eight sentinel sites (Each sentinel with four localities) using a pre-defined questionnaire during June–September 2012. Household heads of 45 houses from each locality were selected randomly to participate in the present study. Data were analysed using the Paired Chi Square test and Bray–Curtis method.

Results

A total of 1440 household heads were interviewed. Both districts indicated statistically acceptable similarities (p > 0.05) in age structure, gender, family size and presence of animals. The knowledge on malaria was observed under “Poor” category. The protective measures against mosquito bites, spraying status of houses and occupation pattern were varied significantly in both districts (p < 0.05). Educational level was statistically similar (p > 0.05) in both districts. Majority of the families were identified as living in “Moderate” house type under low economic condition. Both populations were indicated 85 % similarity according to Bray–Curtis analysis.

Conclusion

Lack of awareness in these communities about the disease may facilitate to the re-emerge of malaria.

The effects of electricity network development besides routine malaria control measures in an underdeveloped region in the pre-elimination phase

Background

The main purpose of this study was to investigate the effects of electricity network development on malaria transmission. The study was performed in the rural areas of three districts in Sistan-va-Baluchestan Province, Iran.

Methods

From the mentioned districts, 122 rural communities were selected. The data of the years 2005–2009 were collected retrospectively from data banks of the district health centres and the offices of the local electricity network. Fixed and random effects panel data regression models were fitted to determine the effects of electrification and other variables on malaria transmission during the elimination phase.

Results

It seems that access to electricity of rural communities, if not harmful, has no obvious effect on malaria control and prevention at least during the elimination phase in an underdeveloped region. Elevation above sea level and precipitation during spring and summer were found to be the other important, respectively, time-invariant and time-dependent variables associated with decreasing and increasing malaria transmission. Indoor residual spraying and the use of insecticide-treated mosquito nets were not found to be effective in decreasing malaria transmission in the elimination phase.

Conclusions

The introduction of electricity to a rural community does not guarantee an absolutely good effect on the reduction of malaria transmission.

Geography and social distribution of malaria in Indonesian Papua: a cross-sectional study

Background

Despite being one of the world’s most affected regions, only little is known about the social and spatial distributions of malaria in Indonesian Papua. Existing studies tend to be descriptive in nature; their inferences are prone to confounding and selection biases. At the same time, there remains limited malaria-cartographic activity in the region. Analysing a subset (N = 22,643) of the National Basic Health Research 2007 dataset (N = 987,205), this paper aims to quantify the district-specific risk of malaria in Papua and to understand how socio-demographic/economic factors measured at individual and district levels are associated with individual’s probability of contracting the disease.

Methods

We adopt a Bayesian hierarchical logistic regression model that accommodates not only the nesting of individuals within the island’s 27 administrative units but also the spatial autocorrelation among these locations. Both individual and contextual characteristics are included as predictors in the model; a normal conditional autoregressive prior and an exchangeable one are assigned to the random effects. Robustness is then assessed through sensitivity analyses using alternative hyperpriors.

Results

We find that rural Papuans as well as those who live in poor, densely forested, lowland districts are at a higher risk of infection than their counterparts. We also find age and gender differentials in malaria prevalence, if only to a small degree. Nine districts are estimated to have higher-than-expected malaria risks; the extent of spatial variation on the island remains notable even after accounting for socio-demographic/economic risk factors.

Conclusions

Although we show that malaria is geography-dependent in Indonesian Papua, it is also a disease of poverty. This means that malaria eradication requires not only biological (proximal) interventions but also social (distal) ones.

Evaluation of Insecticides Susceptibility and Malaria Vector Potential of Anopheles annularis s.l. and Anopheles vagus in Assam, India

During the recent past, development of DDT resistance and reduction to pyrethroid susceptibility among the malaria vectors has posed a serious challenge in many Southeast Asian countries including India. Current study presents the insecticide susceptibility and knock-down data of field collected Anopheles annularis sensu lato and An. vagus mosquito species from endemic areas of Assam in northeast India. Anopheles annularis s.l. and An. vagus adult females were collected from four randomly selected sentinel sites in Orang primary health centre (OPHC) and Balipara primary health centre (BPHC) areas, and used for testing susceptibility to DDT, malathion, deltamethrin and lambda-cyhalothrin. After insecticide susceptibility tests, mosquitoes were subjected to VectorTest™ assay kits to detect the presence of malaria sporozoite in the mosquitoes. An. annularis s.l. was completely susceptible to deltamethrin, lambda-cyhalothrin and malathion in both the study areas. An. vagus was highly susceptible to deltamethrin in both the areas, but exhibited reduced susceptibility to lambda-cyhalothrin in BPHC. Both the species were resistant to DDT and showed very high KDT50 and KDT99 values for DDT. Probit model used to calculate the KDT50 and KDT99 values did not display normal distribution of percent knock-down with time for malathion in both the mosquito species in OPHC (p<0.05) and An. vagus in BPHC (χ2 = 25.3; p = 0.0), and also for deltamethrin to An. vagus in BPHC area (χ2 = 15.4; p = 0.004). Minimum infection rate (MIR) of Plasmodium sporozoite for An. vagus was 0.56 in OPHC and 0.13 in BPHC, while for An. annularis MIR was found to be 0.22 in OPHC. Resistance management strategies should be identified to delay the expansion of resistance. Testing of field caught Anopheles vectors from different endemic areas for the presence of malaria sporozoite may be useful to ensure their role in malaria transmission.