Malaria elimination: situation analysis of cases in India, the state of Madhya Pradesh in central India, and district Mandla of Madhya Pradesh

India contributed approximately 66% of the malaria cases in the WHO South-East Asia region in 2022. In India, approximately 44% of cases have been reported to be disproportionately contributed by approximately 27 districts. A comparative analysis of reported malaria cases between January 2017 and December 2022 was performed in Mandla district, which is the site of a model malaria elimination demonstration project (MEDP) in Madhya Pradesh (MP), India. Compared to 2017, the decrease in malaria cases in Mandla from 2018 to 2022 was higher than MP and the rest of the country. The reduction of cases was significant in 2018, 2019, and 2021 (p < 0.01) (Mandla vs. MP) and was highly significant during 2018-2022 (p < 0.001) (Mandla vs. India). Robust surveillance and real-time data-based decisions accompanied by appropriate management, operational controls, and independent reviews, all designed for resource optimisation, were the reasons for eliminating indigenous malaria in Mandla district. The increase in infection rates during the months immediately following rains suggests that surveillance, vector control, and case management efforts should be specifically intensified for eliminating imported and indigenous cases in the near-elimination districts to work towards achieving the national elimination goal of 2030.

Time series analysis of malaria cases to assess the impact of various interventions over the last three decades and forecasting malaria in India towards the 2030 elimination goals

BACKGROUND

Despite the progress made in this decade towards malaria elimination, it remains a significant public health concern in India and many other countries in South Asia and Asia Pacific region. Understanding the historical trends of malaria incidence in relation to various commodity and policy interventions and identifying the factors associated with its occurrence can inform future intervention strategies for malaria elimination goals.

METHODS

This study analysed historical malaria cases in India from 1990 to 2022 to assess the annual trends and the impact of key anti-malarial interventions on malaria incidence. Factors associated with malaria incidence were identified using univariate and multivariate linear regression analyses. Generalized linear, smoothing, autoregressive integrated moving averages (ARIMA) and Holt's models were used to forecast malaria cases from 2023 to 2030.

RESULTS

The reported annual malaria cases in India during 1990-2000 were 2.38 million, which dropped to 0.73 million cases annually during 2011-2022. The overall reduction from 1990 (2,018,783) to 2022 (176,522) was 91%. The key interventions of the Enhanced Malaria Control Project (EMCP), Intensified Malaria Control Project (IMCP), use of bivalent rapid diagnostic tests (RDT-Pf/Pv), artemisinin-based combination therapy (ACT), and involvement of the Accredited Social Health Activists (ASHAs) as front-line workers were found to result in the decline of malaria significantly. The ARIMA and Holt's models projected a continued decline in cases with the potential for reaching zero indigenous cases by 2027-2028. Important factors influencing malaria incidence included tribal population density, literacy rate, health infrastructure, and forested and hard-to-reach areas.

CONCLUSIONS

Studies aimed at assessing the impact of major commodity and policy interventions on the incidence of disease and studies of disease forecasting will inform programmes and policymakers of steps needed during the last mile phase to achieve malaria elimination. It is proposed that these time series and disease forecasting studies should be performed periodically using granular (monthly) and meteorological data to validate predictions of prior studies and suggest any changes needed for elimination efforts at national and sub-national levels.

Science of malaria elimination: using knowledge of bottlenecks and enablers from the Malaria Elimination Demonstration Project in Central India for eliminating malaria in the Asia Pacific region

Malaria poses a major public health challenge in the Asia Pacific. Malaria Elimination Demonstration Project was conducted as a public-private partnership initiative in Mandla between State government, ICMR, and FDEC India. The project employed controls for efficient operational and management decisions. IEC campaigns found crucial in schools and communities. Capacity building of local workers emphasized for better diagnosis and treatment. SOCH mobile app launched for complete digitalization. Better supervision for Indoor Residual Sprays and optimized Long Lasting Insecticidal Nets distribution. Significant malaria cases reduction in Mandla. Insights from MEDP crucial for malaria elimination strategies in other endemic regions of the Asia Pacific.

Assessment of Plasmodium falciparum drug resistance associated molecular markers in Mandla, Madhya Pradesh, India

BACKGROUND

Resistance against artemisinin-based combination therapy is one of the challenges to malaria control and elimination globally. Mutations in different genes (Pfdhfr, Pfdhps, Pfk-13 and Pfmdr1) confer resistance to artesunate and sulfadoxine-pyrimethamine (AS + SP) were analysed from Mandla district, Madhya Pradesh, to assess the effectiveness of the current treatment regimen against uncomplicated Plasmodium falciparum.

METHODS

Dried blood spots were collected during the active fever survey and mass screening and treatment activities as part of the Malaria Elimination Demonstration Project (MEDP) from 2019 to 2020. Isolated DNA samples were used to amplify the Pfdhfr, Pfdhps, Pfk13 and Pfmdr1 genes using nested PCR and sequenced for mutation analysis using the Sanger sequencing method.

RESULTS

A total of 393 samples were subjected to PCR amplification, sequencing and sequence analysis; 199, 215, 235, and 141 samples were successfully sequenced for Pfdhfr, Pfdhps, Pfk13, Pfmdr1, respectively. Analysis revealed that the 53.3% double mutation (C59R, S108N) in Pfdhfr, 89.3% single mutation (G437A) in Pfdhps, 13.5% single mutants (N86Y), and 51.1% synonymous mutations in Pfmdr1 in the study area. Five different non-synonymous and two synonymous point mutations found in Pfk13, which were not associated to artemisinin resistance.

CONCLUSION

The study has found that mutations linked to SP resistance are increasing in frequency, which may reduce the effectiveness of this drug as a future partner in artemisinin-based combinations. No evidence of mutations linked to artemisinin resistance in Pfk13 was found, suggesting that parasites are sensitive to artemisinin derivatives in the study area. These findings are a baseline for routine molecular surveillance to proactively identify the emergence and spread of artemisinin-resistant parasites.

A comparative assessment of the community frontline health workers for their knowledge and practices of malaria diagnosis and treatment in three contiguous districts Mandla, Balaghat, and Dindori of Madhya Pradesh, India

BACKGROUND

Global malaria cases rose by 14 million, and deaths by 69,000, in 2020. In India, a 46% decline has been reported between 2020 and 2019. In 2017, the Malaria Elimination Demonstration Project conducted a needs-assessment of the Accredited Social Health Activists (ASHAs) of Mandla district. This survey revealed the inadequate level of knowledge in malaria diagnosis and treatment. Subsequently, a training programme was launched for enhancing malaria-related knowledge of ASHAs. The present study was conducted in 2021 to evaluate the impact of training on malaria-related knowledge and practices of ASHAs in Mandla. This assessment was also done in two adjoining districts: Balaghat and Dindori.

METHODS

A cross-sectional survey using a structured questionnaire was administered to ASHAs to measure their knowledge and practices related to malaria etiology, prevention, diagnosis, and treatment. A comparison of information collected from these three districts was performed using simple descriptive statistics, comparison of means and multivariate logistic regression analysis.

RESULTS

Significant improvement was noted amongst ASHAs of district Mandla between 2017 (baseline) and 2021 (endline) in knowledge related to malaria transmission, preventive measures, adherence to the national drug policy, diagnosis using rapid diagnostic tests, and identification of age group-specific, colour-coded artemisinin combination therapy blister packs (p < 0.05). The multivariate logistic regression analysis revealed that odds of Mandla baseline was 0.39, 0.48, 0.34, and 0.07 times lower for malaria-related knowledge on disease etiology, prevention, diagnosis, and treatment, respectively (p < 0.001). Further, participants in districts Balaghat and Dindori showed significantly lower odds for knowledge (p < 0.001) and treatment practices (p < 0.01) compared to Mandla endline. Education, attended training, having a malaria learner's guide, and minimum 10 years' work experience were potential predictors for good treatment practices.

CONCLUSION

The findings of the study unequivocally establishes significant improvement in overall malaria-related knowledge and practices of ASHAs in Mandla as a result of periodic training and capacity building efforts. The study suggests that learnings from Mandla district could be helpful in improving level of knowledge and practices among frontline health workers.

Evaluation of the model malaria elimination strategy in Mandla district along with its neighbouring districts: a time series analysis from 2008 to 2020

BACKGROUND

Compared to 2017, India achieved a significant reduction in malaria cases in 2020. Madhya Pradesh (MP) is a tribal dominated state of India with history of high malaria burden in some districts. District Mandla of MP state showed a considerable decline in malaria cases between 2000 and 2013, except in 2007. Subsequently, a resurgence of malaria cases was observed during 2014 and 2015. The Malaria Elimination Demonstration Project (MEDP) was launched in 2017 in Mandla with the goal to achieve zero indigenous malaria cases. This project used: (1) active surveillance and case management using T4 (Track fever, Test fever, Treat patient, and Track patient); (2) vector control using indoor residual sprays and long-lasting insecticidal nets; (3) information education communication and behaviour change communication; and (4) regular monitoring and evaluation with an emphasis on operational and management accountability. This study has investigated malaria prevalence trends from 2008 to 2020, and has predicted trends for the next 5 years for Mandla and its bordering districts.

METHODS

The malaria prevalence data of the district Mandla for the period of January 2008 to August 2017 was obtained from District Malaria Office (DMO) Mandla and data for the period of September 2017 to December 2020 was taken from MEDP data repository. Further, the malaria prevalence data for the period of January 2008 to December 2020 was collected from DMOs of the neighbouring districts of Mandla. A univariate time series and forecast analysis was performed using seasonal autoregressive integrated moving average model.

FINDINGS

Malaria prevalence in Mandla showed a sharp decline [- 87% (95% CI - 90%, - 84%)] from 2017 to 2020. The malaria forecast for Mandla predicts zero cases in the next 5 years (2021-2025), provided current interventions are sustained. By contrast, the model has forecasted a risk of resurgence of malaria in other districts in MP (Balaghat, Dindori, Jabalpur, Seoni, and Kawardha) that were not the part of MEDP.

CONCLUSION

The interventions deployed as part of MEDP have resulted in a sustainable zero indigenous malaria cases in Mandla. Use of similar strategies in neighbouring and other malaria-endemic districts in India could achieve similar results. However, without adding extra cost to the existing intervention, sincere efforts are needed to sustain these interventions and their impact using accountability framework, data transparency, and programme ownership from state to district level.

Sinococuline, a bioactive compound of Cocculus hirsutus has potent anti-dengue activity

Dengue virus (DENV) infection has increased worldwide, with over 400 million infections annually, and has become a serious public health concern. Several drug candidates, new and repurposed, have failed to meet the primary efficacy endpoints. We have recently shown that Aqueous Extract of the stem of Cocculus hirsutus (AQCH) was effective in vitro and in vivo against DENV and was safe in humans. We now report that an active ingredient of AQCH, Sinococuline, protects against the antibody-mediated secondary-DENV infection in the AG129 mouse model. DENV infection markers were assessed, viz. serum viremia and vital organs pathologies-viral load, proinflammatory cytokines and intestinal vascular leakage. The treatment with Sinococuline at 2.0 mg/kg/day; BID (twice a day), was the most effective in protecting the severely DENV-infected AG129 mice. Also, this dose effectively reduced serum viremia and tissue-viral load and inhibited the elevated expression levels of proinflammatory cytokines (TNF-α and IL-6) in several vital organs. Based on these findings, it could be explored further for pre-clinical and clinical developments for the treatment of dengue.

Mass screening and treatment (MSaT) for identifying and treating asymptomatic cases of malaria-malaria elimination demonstration project (MEDP), Mandla, Madhya Pradesh

BACKGROUND

Mass screening and treatment (MSaT) aims at reducing the spread of malaria in communities by identifying and treating infected persons regardless of the symptoms. This study was conducted to identify and treat asymptomatic cases using MSaT approaches in the community.

METHODS

Three rounds of MSaT using cluster combination approaches were carried out during September 2018 to December 2019 to identify and treat asymptomatic malaria cases in the community. All individuals who were present in the household were screened using RDT irrespective of malaria related symptoms. Simultaneously thick and thin blood smear and blood spot were collected for further analysis using microscopy and diagnostic PCR done in a subset of the samples.

RESULTS

Logistic regression analysis revealed that asymptomatic malaria cases significantly less among the older age groups compared with < 5 years children (OR ranged between 0.52 and 0.61; p < 0.05), lowest in cluster 4 (OR = 0.01; p < 0.0001); during third round of MSaT survey (OR = 0.11; p < 0.0001) and significantly higher in moderate to high endemic areas (OR = 88.30; p < 0.0001).

CONCLUSION

Over the three rounds of MSaT, the number of asymptomatic cases were significantly less in the older age groups, and during third round. Similarly, the asymptomatic cases were significantly less in the low endemic area with API < 1 (cluster four). Therefore, the malaria elimination programme may consider the MSaT strategy to identify asymptomatic cases that would be otherwise missed by routine fever based surveillance. This MSaT strategy would help accomplish the malaria elimination goal in an expedited manner.

A qualitative study on community perceptions on quality of healthcare services they received in the Malaria Elimination Demonstration Project in district Mandla, India

BACKGROUND

The utilization and impact of the healthcare services depend on the perceived quality, appropriateness, ease of availability, and cost of the services. This study aimed to understand the community's perception of the quality of healthcare services delivered as part of the Malaria Elimination Demonstration Project (MEDP), Mandla, Madhya Pradesh, India.

METHODS

The study used qualitative techniques to analyze the community perceptions that emerged from the participants' narratives during the Focus Group Discussions (FGDs) and in-depth Interviews with Key Informants (IKIs) on the promptness and quality of healthcare service delivery, the behaviour of MEDP staff, Information, Education and Communication, and Behavioural Change Communication activities, coordination with community members and other health personnel, and capacity building of healthcare workers and the community.

RESULTS

36 FGDs and 63 IKIs with 419 respondents were conducted in nine blocks of district Mandla. Overall, 97% to 100% of beneficiaries associated MEDP with regularity and prompt service delivery, availability of diagnostics and drugs, friendly behaviour, good coordination, and community mobilization to enhance treatment-seeking behaviour.

CONCLUSIONS

The study's findings highlighted the importance of building and maintaining the community's participation and promoting the demand for optimal utilization of healthcare services inside the village to promptly achieve the malaria elimination goal.

Significance of nested PCR testing for the detection of low-density malaria infection amongst febrile patients from the Malaria Elimination Demonstration Project in Mandla, Madhya Pradesh, India

Background

Low-density malaria infections (LDMI) are defined as infections that are missed by the rapid diagnostic test (RDT) and/or microscopy which can lead to continued transmission and poses a challenge in malaria elimination efforts. This study was conducted to investigate the prevalence of LDMI in febrile cases using species-specific nested Polymerase Chain Reaction (PCR) tests in the Malaria Elimination Demonstration Project, where routine diagnosis was conducted using RDT.

Methods

Every 10th fever case from a cross-sectional community based fever surveillance was tested with RDT, microscopy and nested PCR. Parasite DNA was isolated from the filter paper using Chelex based method. Molecular diagnosis by nested PCR was performed targeting 18SrRNA gene for Plasmodium species.

Results

The prevalence of malaria was 2.50% (436/17405) diagnosed by PCR, 1.13% (196/17405) by RDT, and 0.68% (118/ 17,405) by microscopy. Amongst 17,405 febrile samples, the prevalence of LDMI was 1.51% (263/17405) (95% CI 1.33–1.70), which were missed by conventional methods. Logistic regression analysis revealed that illness during summer season [OR = 1.90 (p < 0.05)] and cases screened within three days of febrile illness [OR = 5.27 (p < 0.001)] were the statistically significant predictors of LDMI.

Conclusion

The prevalence of malaria among febrile cases using PCR was 2.50% (436/17405) as compared to 1.13% (196/17405) by RDT. Higher number of the LDMI cases were found in subjects with ≤ 3 days mean duration of reported fever, which was statistically significant (p < 0.001). This observation suggests that an early detection of malaria with a more sensitive diagnostic method or repeat testing of the all negative cases may be useful for curtailing malaria transmission. Therefore, malaria elimination programme would benefit from using more sensitive and specific diagnostic methods, such as PCR.

Clinical safety and pharmacokinetic evaluation of aqueous extract of Cocculus hirsutus, an anti-viral phytopharmacetical drug as a potential for the treatment of dengue and COVID-19

Background and aim

Dengue a worldwide concern for public health has no effective vaccine or drug available for its prevention or treatment. There are billions of people who are at risk of contracting the dengue virus (DENV) infections with only anti-mosquito strategies to combat this disease. Based on the reports, particularly in vitro studies and small animal studies showing anti-viral activity of aqueous extract of Cocculus hirsutus (AQCH), studies were conducted on AQCH tablets as a potential for the treatment of dengue and COVID-19 infections. The current study was part of the research on AQCH tablet formulation and was aimed to evaluate safety and pharmacokinetics in healthy human subjects.

Materials and methods

Sixty healthy adult human subjects were divided into 5 groups (cohorts: I to V; n = 12 per cohort) and randomized in the ratio of 3:1 to receive active treatment or placebo in a blinded manner. Five doses 100 mg, 200 mg, 400 mg, 600 mg and 800 mg tablets were administered three times daily at an interval of 8 h for days 01–09 under fasting conditions and a single dose in morning on day 10. Safety assessment was based on monitoring the occurrence, pattern, intensity, and severity of adverse events during study period. Blood samples were collected for measurement of the bio-active marker Sinococuline concentrations by a validated LC-MS/MS method followed by pharmacokinetic evaluation.

Results and conclusion

The test formulation was well tolerated in all cohorts. Sinococuline peak plasma concentration (C_max) and total exposure of plasma concentration (AUC) demonstrated linearity up to 600 mg and saturation kinetics at 800 mg dose. There was no difference observed in elimination half-life for all the cohorts, suggesting absence of saturation in rate of elimination. Dose accumulation was observed and steady state was achieved within 3 days. The information on human pharmacokinetics of AQCH tablets would assist in further dose optimization with defined pharmacokinetic-pharmacodynamic relationship.

Monitoring of the Village Malaria Workers to conduct activities of Malaria Elimination Demonstration Project in Mandla, Madhya Pradesh

Background

The capacity of the field staff to conduct activities related to disease surveillance, case management, and vector control has been one of the key components for successfully achieving malaria elimination. India has committed to eliminate malaria by 2030, and it has placed significance on monitoring and evaluation at the district level as one of the key strategies in its national framework. To support and guide the country’s malaria elimination objectives, the Malaria Elimination Demonstration Project was conducted in the tribal district of Mandla, Madhya Pradesh. Robust monitoring of human resources received special attention to help the national programme formulate a strategy to plug the gaps in its supply chain and monitoring and evaluation systems.

Methods

A monitoring tool was developed to test the capabilities of field workers to conduct activities related to malaria elimination work. Between November 2018 to February 2021, twenty-five Malaria Field Coordinators (MFCs) of the project utilized this tool everyday during the supervisory visits for their respective Village Malaria Workers (VMWs). The data was analysed and the scores were tested for variations against different blocks, educational status, duration of monitoring, and post-training scores.

Results

During the study period, the VMWs were monitored a total of 8974 times using the monitoring tool. Each VMW was supervised an average of 1.8 times each month. The critical monitoring indicators scored well in all seven quarters of the study as monitored by the MFCs. Monitoring by MFCs remained stable at 97.3% in all quarters. Contrary to expectations, the study observed longer diagnosis to treatment initiation time in urban areas of the district.

Conclusion

This study demonstrated the significance of a robust monitoring tool as an instrument to determine the capacity of the field workers in conducting surveillance, case management, and vector control related work for the malaria elimination programme. Similar tools can be replicated not only for malaria elimination, but other public health interventions as well.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-04040-2.

Cocculus hirsutus-Derived Phytopharmaceutical Drug Has Potent Anti-dengue Activity

Dengue is a serious public health concern worldwide, with ∼3 billion people at risk of contracting dengue virus (DENV) infections, with some suffering severe consequences of disease and leading to death. Currently, there is no broad use vaccine or drug available for the prevention or treatment of dengue, which leaves only anti-mosquito strategies to combat the dengue menace. The present study is an extension of our earlier study aimed at determining the in vitro and in vivo protective effects of a plant-derived phytopharmaceutical drug for the treatment of dengue. In our previous report, we had identified a methanolic extract of aerial parts of Cissampelos pareira to exhibit in vitro and in vivo anti-dengue activity against all the four DENV serotypes. The dried aerial parts of C. pareira supplied by local vendors were often found to be mixed with aerial parts of another plant of the same Menispermaceae family, Cocculus hirsutus, which shares common homology with C. pareira. In the current study, we have found C. hirsutus to have more potent anti-dengue activity as compared with C. pareira. The stem part of C. hirsutus was found to be more potent (∼25 times) than the aerial part (stem and leaf) irrespective of the extraction solvent used, viz., denatured spirit, hydro-alcohol (50:50), and aqueous. Moreover, the anti-dengue activity of stem extract in all the solvents was comparable. Hence, an aqueous extract of the stem of C. hirsutus (AQCH) was selected due to greater regulatory compliance. Five chemical markers, viz., Sinococuline, 20-Hydroxyecdysone, Makisterone-A, Magnoflorine, and Coniferyl alcohol, were identified in fingerprinting analysis. In a test of primary dengue infection in the AG129 mice model, AQCH extract at 25 mg/kg body weight exhibited protection when administered four and three times a day. The AQCH was also protective in the secondary DENV-infected AG129 mice model at 25 mg/kg/dose when administered four and three times a day. Additionally, the AQCH extract reduced serum viremia and small intestinal pathologies, viz., viral load, pro-inflammatory cytokines, and vascular leakage. Based on these findings, we have undertaken the potential preclinical development of C. hirsutus-based phytopharmaceutical, which could be studied further for its clinical development for treating dengue.

Learnings from two independent malaria elimination demonstration projects in India

PROBLEM

India and sub-Saharan Africa contributes about 85% of the global malaria burden, and India is committed to eliminating malaria by 2030.

APPROACH

Two novel initiatives-the Malaria Elimination Demonstration Project (MEDP) in Madhya Pradesh and Durgama Anchalare Malaria Nirakaran (DAMaN) in Odisha-were initiated independently to demonstrate that indigenous malaria can be eliminated in a short period of time.

LOCAL SETTING

These initiatives focused on rural, tribal areas where there is a high malaria burden and complex epidemiology.

RELEVANT CHANGES

The case management and vector control strategies used in these programmes were based on the national guidelines, with context-specific changes and introduction of accountability at management, operational, technical and financial levels. The MEDP achieved a 91% reduction in malaria cases and recorded zero transmission for 6 consecutive and a total of 9 mo. The DAMaN project brought about an 88% reduction in malaria cases.

LESSONS LEARNED

Malaria elimination will require robust surveillance and case management, monitoring of vector control interventions, community-centric information education communication and behaviour change communication initiatives and management controls, as well as regular internal and external reviews.

Arterolane-piperaquine-mefloquine versus arterolane-piperaquine and artemether-lumefantrine in the treatment of uncomplicated Plasmodium falciparum malaria in Kenyan children: a single-centre, open-label, randomised, non-inferiority trial

BACKGROUND

Triple antimalarial combination therapies combine potent and rapidly cleared artemisinins or related synthetic ozonides, such as arterolane, with two, more slowly eliminated partner drugs to reduce the risk of resistance. We aimed to assess the safety, tolerability, and efficacy of arterolane-piperaquine-mefloquine versus arterolane-piperaquine and artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Kenyan children.

METHODS

In this single-centre, open-label, randomised, non-inferiority trial done in Kilifi County Hospital, Kilifi, coastal Kenya, children with uncomplicated Plasmodium falciparum malaria were recruited. Eligible patients were aged 2-12 years and had an asexual parasitaemia of 5000-250 000 parasites per μL. The exclusion criteria included the presence of an acute illness other than malaria, the inability to tolerate oral medications, treatment with an artemisinin derivative in the previous 7 days, a known hypersensitivity or contraindication to any of the study drugs, and a QT interval corrected for heart rate (QTc interval) longer than 450 ms. Patients were randomly assigned (1:1:1), by use of blocks of six, nine, and 12, and opaque, sealed, and sequentially numbered envelopes, to receive either arterolane-piperaquine, arterolane-piperaquine-mefloquine, or artemether-lumefantrine. Laboratory staff, but not the patients, the patients' parents or caregivers, clinical or medical officers, nurses, or trial statistician, were masked to the intervention groups. For 3 days, oral artemether-lumefantrine was administered twice daily (target dose 5-24 mg/kg of bodyweight of artemether and 29-144 mg/kg of bodyweight of lumefantrine), and oral arterolane-piperaquine (arterolane dose 4 mg/kg of bodyweight; piperaquine dose 20 mg/kg of bodyweight) and oral arterolane-piperaquine-mefloquine (mefloquine dose 8 mg/kg of bodyweight) were administered once daily. All patients received 0·25 mg/kg of bodyweight of oral primaquine at hour 24. All patients were admitted to Kilifi County Hospital for at least 3 consecutive days and followed up at day 7 and, thereafter, weekly for up to 42 days. The primary endpoint was 42-day PCR-corrected efficacy, defined as the absence of treatment failure in the first 42 days post-treatment, of arterolane-piperaquine-mefloquine versus artemether-lumefantrine, and, along with safety, was analysed in the intention-to-treat population, which comprised all patients who received at least one dose of a study drug. The 42-day PCR-corrected efficacy of arterolane-piperaquine-mefloquine versus arterolane-piperaquine was an important secondary endpoint and was also analysed in the intention-to-treat population. The non-inferiority margin for the risk difference between treatments was -7%. The study is registered in ClinicalTrials.gov, NCT03452475, and is completed.

FINDINGS

Between March 7, 2018, and May 2, 2019, 533 children with P falciparum were screened, of whom 217 were randomly assigned to receive either arterolane-piperaquine (n=73), arterolane-piperaquine-mefloquine (n=72), or artemether-lumefantrine (n=72) and comprised the intention-to-treat population. The 42-day PCR-corrected efficacy after treatment with arterolane-piperaquine-mefloquine (100%, 95% CI 95-100; 72/72) was non-inferior to that after treatment with artemether-lumefantrine (96%, 95% CI 88-99; 69/72; risk difference 4%, 95% CI 0-9; p=0·25). The 42-day PCR-corrected efficacy of arterolane-piperaquine-mefloquine was non-inferior to that of arterolane-piperaquine (100%, 95% CI 95-100; 73/73; risk difference 0%). Vomiting rates in the first hour post-drug administration were significantly higher in patients treated with arterolane-piperaquine (5%, 95% CI 2-9; ten of 203 drug administrations; p=0·0013) or arterolane-piperaquine-mefloquine (5%, 3-9; 11 of 209 drug administrations; p=0·0006) than in patients treated with artemether-lumefantrine (1%, 0-2; three of 415 drug administrations). Upper respiratory tract complaints (n=26 for artemether-lumefantrine; n=19 for arterolane-piperaquine-mefloquine; n=23 for arterolane-piperaquine), headache (n=13; n=4; n=5), and abdominal pain (n=7; n=5; n=5) were the most frequently reported adverse events. There were no deaths.

INTERPRETATION

This study shows that arterolane-piperaquine-mefloquine is an efficacious and safe treatment for uncomplicated falciparum malaria in children and could potentially be used to prevent or delay the emergence of antimalarial resistance.

FUNDING

UK Department for International Development, The Wellcome Trust, The Bill & Melinda Gates Foundation, Sun Pharmaceutical Industries.

Assessing community knowledge, attitude and practices to strengthen communication strategy for Malaria Elimination Demonstration Project in Mandla

BACKGROUND

Changes in social, belief, and behavioural practices are essential for the success of any public health delivery programme. In the planning stages of the Malaria Elimination Demonstration Project (MEDP), priority was given to communication with a goal to develop capacity of health workers and to improve the knowledge, attitude and practices (KAP) of the people of Mandla. This paper describes the level of community knowledge on malaria, including its prevention, diagnosis, treatment-seeking behaviour, and the level of satisfaction with the services provided by the project.

METHODS

A cross sectional survey was undertaken in 1233 villages of Mandla to study the KAP and self-assessed improvement in knowledge and satisfaction level of the community. The goal of the study was to understand whether there is need for strengthening communication strategy of MEDP for better impact. The survey was conducted amongst the head/eligible members of the 733 households located in the nine blocks of the district using clustered random sampling.

RESULTS

Though four-fifths of the respondents were able to correlate the transmission of malaria with mosquitoes, misconceptions existed among them. The types of malaria were not known to everyone. Only 39% were aware of the Indoor Residual Spray (IRS) and 41% understood the value of Long-Lasting Insecticidal Nets (LLIN). Around 71% of subjects surveyed were aware of the proper diagnostic tests for malaria. A total of 87% of the respondents knew about the MEDP staff working in their respective villages.

CONCLUSION

The study reported gaps in knowledge on malaria at community level. The self-assessment of the community revealed that the communication strategy established by MEDP in Mandla district has been useful to them as they are becoming better informed about the prevention and treatment aspects of disease. The lessons learned as revealed in the KAP survey will improve malaria elimination outcomes in a timely manner.

Improvement of Indoor Residual Spraying and Long-Lasting Insecticidal Net services through structured monitoring and supervision as part of the Malaria Elimination Demonstration Project in Mandla, Madhya Pradesh

Background

The Government of Madhya Pradesh employed Indoor Residual Spraying (IRS) with alpha-cypermethrin synthetic pyrethroids in sub-centres with Annual Parasite Incidence (API) from 2 to 4.99. In sub-centres with API more than 5, Long-Lasting Insecticidal Nets (LLINs) were distributed. At the request of the State Government, the Malaria Elimination Demonstration Project (MEDP) staff observed and provided support to both IRS and LLINs campaigns. In the year 2017, the study team monitored only the IRS campaigns, however, in the year 2018, the supportive supervision was provided to the IRS campaign teams along with post-distribution monitoring of the LLINs.

Methods

The study was carried out during IRS spraying using a pre-tested, closed-ended monitoring checklist which consisted of two parts- observations of spraying team and observation of sprayed houses. For LLINs, a sample of the households that received the bed nets was taken for the study. For IRS, the spraying teams were monitored for quality and technique for a total of 159 times in 2017 and 183 times in the year 2018, respectively. For post spraying observations, a total of 1261 and 1791 households were observed in the years 2017 and 2018, respectively. The use of LLINs was observed in 5 % of the households in 2018 and 2020, which is about 2,000 houses in each survey where each house received about 2.5 LLINs per household. The results of surveys were compared to assess impact of supportive supervision and monitoring.

Results

Significant improvement was noted after supportive supervision in year 2018 in various aspects of spraying. Preparedness of spraying, such as advance information to villagers, presence of equipment and records improved by up to 70 %. The methodology of spraying preparation improved from 50 to 90 %, spraying technique improved from 54 to 80 %, and proper use equipment during spraying improved from 51 to 92 %. After eight months post distribution of the LLINs in 2019, improvement was seen in regular usage of LLINs by 28 %. It was found that on-spot demonstrations during distribution and carrying of LLINs when sleeping outside homes increased by 56 %. Results of IEC campaigns revealed the reduction in adverse effects by 64 % and increase in awareness by 97 %.

Conclusions

Effective supervision improved the quality of IRS and usage of LLINs in the study area. Based on these results, continued training and monitoring of staff that is deployed to spraying houses and distribute bed nets was suggested. The study also revealed that proper IEC/BCC drives help increase community acceptance of vector control measures and their rational usage.

A comprehensive mobile application tool for disease surveillance, workforce management and supply chain management for Malaria Elimination Demonstration Project

BACKGROUND

Health care technologies are now offering accountability, quality, robustness, and accuracy in disease surveillance and health care delivery programmes. With the advent of mobile hand-held devices, these technologies have become more accessible and adaptable for use by field staff working in remote areas. The Malaria Elimination Demonstration Project started collection of data and conduct of routine operations using paper-based reporting systems. Observing the need for a robust and quality digital mobile application, a comprehensive mobile application tool was developed that allowed the project to conduct disease surveillance, workforce management and supply chain management.

METHODS

In June 2017, the project conceptualized a comprehensive mobile application tool in the local language (Hindi) for disease surveillance, human resources management, and supply chain management. The tool is also available in English. Solution for Community Health-workers (SOCH) mobile app is an android native application developed using android SDK and web-based tool using MVC.net framework. Construction of the application started in November 2017 and rolled out its pilot in April 2018, followed by pan-district roll out in July 2018. The application uses self-validation tools to ensure high level of data quality and integrity.

RESULTS

The software is available in android based hand-held devices and web-screens with built-in data analytical capabilities. Using SOCH, the project has now successfully digitized its routine surveillance, attendance, tour plans, supply chain management components. The project has documented a reduction in 91% indigenous cases in the district, 60% improvement in stock accountability, and 99.6% accuracy in data collected through the mobile application.

CONCLUSION

SOCH is an excellent and user-friendly tool, which can be customized for any public health management programme. The system ensures accountability and data robustness, which is needed for malaria elimination efforts throughout the country. The mobile application can be adapted for English or any other Indian or international language for use for malaria or any other disease surveillance and control programme. Another expansion feature of this mobile application is incorporation of indicators for Indoor Residual Spraying (IRS), Long-Lasting Insecticidal Nets (LLINs), and minor engineering by the residents of community under surveillance. The authors believe that it would be highly desirable and appropriate for an international organization, such as the World Health Organization (WHO), to conduct an independent comparison of all available mobile e-surveillance tools, so that a high-performing and globally suitable system can be selected for use in malaria elimination programmes. The Foundation of Disease Elimination and Controlof India has decided to make the SOCH mobile application available to anyone who would like to use it for disease surveillance and health care programmes.

A model for malaria elimination based on learnings from the Malaria Elimination Demonstration Project, Mandla district, Madhya Pradesh

Background

Malaria Elimination Demonstration Project (MEDP) was started as a Public-Private-Partnership between the Indian Council of Medical Research through National Institute of Research in Tribal Health, Govt. of Madhya Pradesh and Foundation of Disease Elimination and Control of India, which is a Corporate Social Responsibility (CSR) initiative of the Sun Pharmaceutical Industries Limited. The project’s goal was to demonstrate that malaria can be eliminated from a high malaria endemic district along with prevention of re-establishment of malaria and to develop a model for malaria elimination using the lessons learned and knowledge acquired from the demonstration project.

Methods

The project employed tested protocols of robust surveillance, case management, vector control, and capacity building through continuous evaluation and training.  The model was developed using the learnings from the operational plan, surveillance and case management, monitoring and feedback, entomological investigations and vector control, IEC and capacity building, supply chain management, mobile application (SOCH), and independent reviews of MEDP.

Results

The MEDP has been operational since April 2017 with field operations from August 2017, and has observed: (1) reduction in indigenous cases of malaria by about 91 %; (2) need for training and capacity building of field staff for diagnosis and treatment of malaria; (3) need for improvement insecticide spraying and for distribution and usage of bed-nets; (4) need for robust surveillance system that captures and documents information on febrile cases, RDT positive individuals, and treatments provided; (5) need for effective supervision of field staff based on advance tour plan; (6) accountability and controls from the highest level to field workers; and (7) need for context-specific IEC.

Conclusions

Malaria elimination is a high-priority public health goal of the Indian Government with a committed deadline of 2030. In order to achieve this goal, built-in systems of accountability, ownership, effective management, operational, technical, and financial controls will be crucial components for malaria elimination in India. This manuscript presents a model for malaria elimination with district as an operational unit, which may be considered for malaria elimination in India and other countries with similar geography, topography, climate, endemicity, health infrastructure, and socio-economic characteristics.

Assessment of ASHA for knowledge, diagnosis and treatment on malaria in Mandla district of Madhya Pradesh as part of the malaria elimination demonstration project

Background

The role of Accredited Social Health Activist (ASHA) in the health care delivery services at the periphery level is crucial for achieving disease prevention, control and elimination goals. The objective of the study was to assess the knowledge, attitude, practices, priorities and capability of ASHA related to malaria diagnosis and treatment as part of the Malaria Elimination Demonstration Project in 1233 villages of district Mandla, Madhya Pradesh.

Methods

A cross sectional study was conducted using a fully structured, pre-tested interview schedule during June and July 2017 (before the field operations of MEDP were started). Two hundred twenty (17%) of the total ASHAs were selected for the interview from the 9 developmental blocks of Mandla district.

Results

Knowledge, Attitude and Practices (KAP) study revealed that most ASHAs knew that mosquitoes are the main agent for spread of malaria (97.7%). They mostly used Rapid Diagnostic Test (RDT) for diagnosis (91.8%). The majority (87.3%) correctly identified negative RDT result while only 15% and 10.5%, respectively, identified Plasmodium vivax and Plasmodium falciparum positive cases correctly. Further analysis showed that 85% ASHAs used chloroquine, 44.5% used artemisinin-based combination therapy (ACT), and 55.5% used primaquine for treatment of malaria. It was also found that only 38.2% ASHA gave PQ for 14 days in cases of P. vivax. At the time of the interview, 19.1% ASHAs did not have any RDTs for diagnosis and 47.7% reported not having ACT for treatment of P. falciparum malaria.

Conclusions

This study has revealed that ASHAs in the test district were not adequately trained or stocked for malaria parasite species identification and treatment, which are the major components of malaria elimination programme. This study has, therefore, revealed a need for training ASHAs on testing by RDT and proper treatment regimen for P. vivax and P. falciparum.

Significance of training, monitoring and assessment of malaria workers in achieving malaria elimination goal of Malaria Elimination Demonstration Project

Background

The Malaria Elimination Demonstration Project (MEDP) maintained a workforce of 235 Village Malaria Workers (VMWs) and 25 Malaria Field Coordinators (MFCs) to conduct disease surveillance, case management, IEC/BCC activities, capacity building, and monitoring of vector control activities in 1233 villages of Mandla, a high malaria endemic district of Madhya Pradesh in central India.

Methods

The induction training was conducted for 3 days on malaria diagnosis, treatment, prevention, and ethics. All trainings were assessed using a pre and post-training assessment questionnaire, with 70% marks as qualifying threshold. The questionnaire was divided into three thematic areas viz. general knowledge related to malaria (KAP), diagnosis and treatment (DXRX), and vector control (PVC).

Results

In 2017, the project trained 330 candidates, followed by 243 and 247 candidates in 2018 and 2019, respectively. 94.3% candidates passed after a single training session. Almost all (95%) candidates showed improvement in knowledge after the training with 4% showing no effect and 1% showing deterioration. Progressive improvement in scores of 2017 cohort was seen along with significant improvement in performance of candidates in 2019 after the introduction of systematic monitoring and ‘shadowing’ training exercises.

Conclusion

The project has successfully demonstrated the value of recruitment of workers from the study area, outcome of training, and performance evaluation of field staff in malaria elimination programme. This careful strategy of recruitment and training resulted in a work-force that was capable of independently conducting surveillance, case management, vector control, and Information Education Communication/Behaviour Change Communication (IEC/BCC). The learnings of this study, including the training modules and monitoring processes, can be used to train the health delivery staff for achieving national goal for malaria elimination by 2030. Similar training and monitoring programmes could also be used for other public health delivery programmes.

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.

A study of malaria vector surveillance as part of the Malaria Elimination Demonstration Project in Mandla, Madhya Pradesh

BACKGROUND

Understanding of malaria vector density, distribution, insecticide resistance, vector incrimination, infection status, and identification of sibling species are some of the essential components of vector control measures for achieving malaria elimination goals.

METHODS

As part of the malaria elimination demonstration project, entomological surveillance was carried out from October 2017 to October 2019 by collecting indoor resting mosquitoes using hand catch method. Susceptibility test was done for determining the insecticide resistance status of vector mosquito Anopheles culicifacies using standard protocols by the World Health Organization. The cone bioassay method was used for determining the efficacy and quality of insecticide sprayed. Mosquitoes collected from different ecotypes were identified and processed for parasite identification, vector incrimination and sibling species determination.

RESULTS

The two known malaria vector species (Anopheles culicifacies and Anopheles fluviatilis) were found in the study area, which have been previously reported in this and adjoining areas of the State of Madhya Pradesh. The prevalence of An. culicifacies was significantly higher in all study villages with peak in July while lowest number was recorded in May. Proportion of vector density was observed to be low in foothill terrains. The other anopheline species viz, Anopheles subpictus, Anopheles annularis, Anopheles vagus, Anopheles splendidus, Anopheles pallidus, Anopheles nigerrimus and Anopheles barbirostris were also recorded in the study area, although their prevalence was significantly less compared to the An. culicifacies. In 2017, An. culicifacies was found to be resistant to dichloro-diphenyl-trichloroethane (DDT) and malathion, with possible resistance to alphacypermethrin and susceptible to deltamethrin. However, in 2019, the species was found to be resistant to alphacypermethrin, DDT, malathion, with possible resistance to deltamethrin. The bioassays revealed 82 to > 98% corrected % mortality of An. culicifacies on day-one post-spraying and 35 to 62% on follow-up day-30. Anopheles culicifacies sibling species C was most prevalent (38.5%) followed by A/D and E while B was least pre-dominant (11.9%). Anopheles fluviatilis sibling species T was most prevalent (74.6%) followed by U (25.4%) while species S was not recorded. One An.culicifacies (sibling species C) was found positive for Plasmodium falciparum by PCR tests in the mosquitoes sampled from the test areas.

CONCLUSION

Based on the nine entomologic investigations conducted between 2017-2019, it was concluded that An. culicifacies was present throughout the year while An. fluviatilis had seasonal presence in the study areas. Anopheles culicifacies was resistant to alphacypermethrin and emerging resistance to deltamethrin was observed in this area. Anopheles culicifacies was confirmed as the malaria vector. This type of information on indigenous malaria vectors and insecticide resistance is important in implementation of vector control through indoor residual spraying (IRS) and use of insecticide-impregnated bed nets for achieving the malaria elimination goals.

Study design and operational framework for a community-based Malaria Elimination Demonstration Project (MEDP) in 1233 villages of district Mandla, Madhya Pradesh

Background

In the past decade substantial reduction in malaria morbidity and mortality has been observed through well-implemented case management and vector control strategies. India has also achieved a significant reduction in malaria burden in 2018 and has committed to eliminate malaria by 2030. The Mandla Malaria Elimination Demonstration Project (MEDP) was started in 2017 in 1233 villages of District Mandla to demonstrate malaria elimination in a tribal district with hard-to-reach areas was possible using active and passive surveillance, case management, vector control, and targeted information, education and communication campaigns. An operational plan was developed to strengthen the existing surveillance and malaria elimination systems, through fortnightly active case detection to ensure that all cases including those that are introduced into the communities are rapidly identified and treated promptly. The plan also focused on the reduction of human-mosquito contact through the use of Long-Lasting Insecticial Nets (LLINs) and Indoor Residual Spray (IRS). The operational plan was modified in view of the present COVID-19 pandemic by creating systems of assistance for the local administration for COVID-related work while ensuring the operational integrity of malaria elimination efforts.

Results

The use of MEDP study design and operational plan, with its built-in management control systems, has yielded significant (91%) reduction of indigenous cases of malaria during the period from June 2017 to May 2020. The malaria positivity rate was 0.33% in 2017–18, 0.13% in 2018–19, and 0.06% in 2019–20. Mass screening revealed 0.18% malaria positivity in September–October 2018, followed by 0.06% in June 2019, and 0.03% in December 2019, and these were mostly asymptomatic cases in the community. The project has been able to sustain the gains of the past three years during the ongoing COVID-19 pandemic.

Conclusion

This paper provides the study design and the operational plan for malaria elimination in a high-burden district of Central India, which presented difficulties of hard to reach areas, forest malaria, and complex epidemiology of urban and rural malaria. The lessons learned could be used for malaria elimination efforts in rest of the country and other parts of South Asia with comparable demography and epidemiology.

Demonstration of indigenous malaria elimination through Track-Test-Treat-Track (T4) strategy in a Malaria Elimination Demonstration Project in Mandla, Madhya Pradesh

BACKGROUND

Many malaria endemic countries are heading towards malaria elimination through the use of case management and vector control strategies, which employ surveillance, improving access to early diagnosis, prompt treatment., and integrated vector control measures. There is a consensus that elimination of malaria is feasible when rapid detection and prompt treatment is combined with mosquito-human contact interruption in an efficient and sustainable manner at community levels. This paper describes results of an integrated case management and vector control strategy for reducing malaria cases in 1233 villages over 3 years in district Mandla, Madhya Pradesh, India.

METHODS

The project enrolled the entire population (1,143,126) of Mandla district for fever surveillance followed by testing of febrile cases and treatment of positive subjects using T4 strategy, which is Track (by fever), Test (by RDTs), Treat (by ACT) and Track (for completion of treatment). In addition to the active and passive surveillance for detection and treatment of febrile cases, the project conducted mass screening and treatment to clear the asymptomatic reservoirs of infection. Febrile cases were also tested in the out-patient department of the District Hospital from June 2018 to September, 2018 and in a community-based medical camp from November 7 to 14, 2019. The project also used vector control measures for interrupting human-mosquito contact, and information, education and communication (IEC) campaigns to increase demand for malaria services at community level.

RESULTS

This project has revealed about 91% reduction of indigenous cases of malaria during the period from June 2017 to May 2020, through case management and vector control strategies. A total 357,143 febrile cases were screened, out of which 0.19% were found positive for the presence of malaria parasites, with Plasmodium falciparum and Plasmodium vivax ratio of 62:38. The prevalence of malaria was higher in individuals > 15 years of age (69% cases). The positivity rate was 0.33% in 2017-18, 0.13% in 2018-19, and 0.06% in 2019-20. In all of the 3 years of the project, the peak transmission correlated with rains. Mass screening revealed 0.18% positivity in Sep-Oct 2018, followed by 0.06% in June 2019, and 0.03% in December 2019, and these were mostly asymptomatic cases in the community. Imported cases into the district were mostly contributed by the distant state of Telangana (51.13%). Fever patients tested for malaria parasites in the District Hospital and medical camp revealed zero cases.

CONCLUSION

Using the current intervention and prevention tools along with optimum utilization of human resources, a 91% reduction in indigenous cases of malaria was seen in the district in 3 years. The reduction was similar in the three high prevalence blocks of the district. These results reveal that malaria elimination is achievable in India within a stipulated time frame. The reduction of malaria at the community level was further validated when zero malaria cases were diagnosed during hospital and community-based studies in Mandla. Prompt detection and treatment of imported/migratory cases may have prevented outbreaks in the district. This project has demonstrated that field programmes backed by adequate technical, management, operational, and financial controls with robust monitoring are needed for achieving malaria elimination.

Dengue and Zika virus infections are enhanced by live attenuated dengue vaccine but not by recombinant DSV4 vaccine candidate in mouse models

Background

A tetravalent live attenuated dengue vaccine, Dengvaxia, sensitised naïve recipients to severe dengue illness upon a subsequent natural dengue infection and is suspected to be due to antibody-dependent enhancement (ADE). ADE has also been implicated in the severe neurological outcomes of Zika virus (ZIKV) infection. It has become evident that cross-reactive antibodies targeting the viral pre-membrane protein and fusion-loop epitope are ADE-competent. A pre-clinical tetravalent dengue sub-unit vaccine candidate, DSV4, eliminates these ADE-competent epitopes.

Methods

We compared protective efficacy and ADE-competence of murine polyclonal antibodies induced by DSV4, Dengvaxia and an ‘in house’ tetravalent mixture of all four laboratory DENV strains, TV DENV, using established mouse models.

Findings

DSV4-induced antibodies, known to be predominantly type-specific, provided significant protection against lethal DENV challenge, but did not promote ADE of either DENV or ZIKV infection in vivo. Antibodies elicited by Dengvaxia and TV DENV, which are predominantly cross-reactive, not only failed to offer protection against lethal DENV challenge, but also promoted ADE of both DENV and ZIKV infection in vivo.

Interpretation

Protective efficacy against DENV infection may be linked to the induction of neutralising antibodies which are type-specific rather than cross-reactive. Whole virus-based dengue vaccines may be associated with ADE risk, despite their potent virus-neutralising capacity. Vaccines designed to eliminate ADE-competent epitopes may help eliminate/minimise ADE risk.

Funding

This study was supported partly by ICGEB, India, the National Biopharma Mission, DBT, Government of India, Sun Pharmaceutical Industries Limited, India, and NIAID, NIH, USA.

Malaria elimination: Using past and present experience to make malaria-free India by 2030

Malaria causes significant morbidity and mortality worldwide. Since 2005, malaria cases have been declining globally with many countries having eliminated malaria and several other countries heading towards malaria elimination. The World Health Organization's Global Technical Strategy for malaria targets at least 90% reduction in case incidences and mortality rates, and elimination in 35 countries by 2030. India along with other Asia-Pacific countries has pledged to eliminate malaria by 2030. Sustainable vector control and case management interventions have played a pivotal role in malaria control leading to elimination. Malaria is complex in India due to the presence of multiple parasites and vectors species, asymptomatic cases, resistance against antimalarials and insecticides, social, demographic, cultural and behavioural beliefs. Therefore, maintaining zero indigenous malaria transmission and preventing malaria through importation of cases requires well-planned multi-pronged intervention strategies. This article provides insights into the past and present malaria control and elimination efforts that may be useful for the national programme for eliminating malaria from India by 2030.

Comparison of multiplex RT-PCR with virus isolation for detection, typing and sub-typing of influenza virus from influenza-like illness cases

PURPOSE

Influenza epidemics and periodic pandemics occur worldwide resulting in significant mortality, morbidity and economic loss. There is need for a sensitive, rapid and cost-effective assay to detect, type and sub-type influenza viruses, as cell culture has a long turnaround time.

MATERIALS AND METHODS

Nasopharyngeal swabs were collected from patients presenting with influenza-like illness (ILI) at AIIMS OPD and Primary Health Centre Ballabhgarh (Haryana). From June 2007 to January 2009 and then from September to November 2009, of 1567 specimens collected, 544 were randomly selected and were tested by virus culture using Madin-Darby Canine Kidney (MDCK) cells and by reverse transcription polymerase chain reaction (RT-PCR) for influenza A using primers for matrix gene and for influenza B using non-structural gene (NS) primers. All influenza A positives were sub-typed using primers for HA and NA genes of A/H1, A/H3. A separate multiplex RT-PCR having primers from matrix and HA genes of pandemic A (H1N1) pdm09 viruses was carried out on samples collected after September 2009.

RESULTS

Of the 544 samples, 136 (25%) were positive for influenza by RT-PCR. Further typing analysis revealed 86 (63.2%) were typed as influenza A and 47 (34.5%) as influenza B viruses and 3 (2%) samples showed dual infection with influenza A and B. Of the 86 influenza A positive samples 48 (55.8%) were identified as seasonal influenza A/H1N1, 22 (25.6%) as A (H1N1) pdm09 and 16 (18.6%) as A/H3N2. Comparison of influenza positivity using virus culture revealed that only 97/136 (71.3%) were influenza positive. Sensitivity of viral detection was lowest for seasonal A/H1 (26/48; 54%), followed by H3N2 (11/16; 68.7%) and influenza B (38/47; 80.8%); all influenza A/H1N1pdm09 viruses were detected by both methods.

CONCLUSION

RT-PCR is a sensitive, low cost and rapid screening test for diagnosing influenza infection during epidemics and pandemics. mRT-PCR increased the detection rates for influenza by 28.6% as compared with virus isolation and thus is a useful assay in both diagnostic and epidemiological settings in resource poor countries.

Serological markers for monitoring historical changes in malaria transmission intensity in a highly endemic region of Western Kenya, 1994-2009

Background

Monitoring local malaria transmission intensity is essential for planning evidence-based control strategies and evaluating their impact over time. Anti-malarial antibodies provide information on cumulative exposure and have proven useful, in areas where transmission has dropped to low sustained levels, for retrospectively reconstructing the timing and magnitude of transmission reduction. It is unclear whether serological markers are also informative in high transmission settings, where interventions may reduce transmission, but to a level where considerable exposure continues.

Methods

This study was conducted through ongoing KEMRI and CDC collaboration. Asembo, in Western Kenya, is an area where intense malaria transmission was drastically reduced during a 1997–1999 community-randomized, controlled insecticide-treated net (ITN) trial. Two approaches were taken to reconstruct malaria transmission history during the period from 1994 to 2009. First, point measurements were calculated for seroprevalence, mean antibody titre, and seroconversion rate (SCR) against three Plasmodium falciparum antigens (AMA-1, MSP-1₁₉, and CSP) at five time points for comparison against traditional malaria indices (parasite prevalence and entomological inoculation rate). Second, within individual post-ITN years, age-stratified seroprevalence data were analysed retrospectively for an abrupt drop in SCR by fitting alternative reversible catalytic conversion models that allowed for change in SCR.

Results

Generally, point measurements of seroprevalence, antibody titres and SCR produced consistent patterns indicating that a gradual but substantial drop in malaria transmission (46-70%) occurred from 1994 to 2007, followed by a marginal increase beginning in 2008 or 2009. In particular, proportionate changes in seroprevalence and SCR point estimates (relative to 1994 baseline values) for AMA-1 and CSP, but not MSP-1₁₉, correlated closely with trends in parasite prevalence throughout the entire 15-year study period. However, retrospective analyses using datasets from 2007, 2008 and 2009 failed to detect any abrupt drop in transmission coinciding with the timing of the 1997–1999 ITN trial.

Conclusions

In this highly endemic area, serological markers were useful for generating accurate point estimates of malaria transmission intensity, but not for retrospective analysis of historical changes. Further investigation, including exploration of different malaria antigens and/or alternative models of population seroconversion, may yield serological tools that are more informative in high transmission settings.

Electronic supplementary material

The online version of this article (doi:10.1186/1475-2875-13-451) contains supplementary material, which is available to authorized users.

Development, Characterization and Immunogenicity of a Multi-Stage, MultivalentPlasmodium falciparumVaccine Antigen (FALVAC-1A) Expressed inEscherichia coli

A synthetic multistage, multi-epitope Plasmodium falciparum malaria antigen (FALVAC-1A) was designed and evaluated in silico, and then the gene was constructed and expressed in Escherichia coli. The FALVAC-1A protein was purified by inclusion body isolation, followed by affinity and ion exchange chromatography. Although FALVAC-1A was a synthetic antigen, it folded to a specific, but as yet incompletely defined, molecular conformation that was stable and comparable from lot to lot. When formulated with four different adjuvants, FALVAC-1A was highly immunogenic in rabbits, inducing not only ELISA reactivity to the cognate antigen and most of its component epitopes, but also in vitro activity against P. falciparum parasites as demonstrated by inhibition of sporozoite invasion, antibody dependent cellular inhibition and the immunofluorescence assay.

The need for targeted implementation research to improve coverage of basic vaccines and introduction of new vaccines

The Decade of Vaccines Collaboration (DoVC) Research and Development (R&D) Working Group identified implementation research as an important step toward achieving high vaccine coverage and the uptake of desirable new vaccines. The R&D Working Group noted that implementation research is highly complex and requires participation of stakeholders from diverse backgrounds to ensure effective planning, execution, interpretation, and adoption of research outcomes. Unlike other scientific disciplines, implementation research is highly contextual and depends on social, cultural, geographic, and economic factors to make the findings useful for local, national, and regional applications. This paper presents the broad framework for implementation research in support of immunization and sets out a series of research questions developed through a Delphi process (during a DoVC-supported workshop in Sitges, Spain) and a literature review.

Polymorphisms in genes of interleukin 12 and its receptors and their association with protection against severe malarial anaemia in children in western Kenya

Background

Malarial anaemia is characterized by destruction of malaria infected red blood cells and suppression of erythropoiesis. Interleukin 12 (IL12) significantly boosts erythropoietic responses in murine models of malarial anaemia and decreased IL12 levels are associated with severe malarial anaemia (SMA) in children. Based on the biological relevance of IL12 in malaria anaemia, the relationship between genetic polymorphisms of IL12 and its receptors and SMA was examined.

Methods

Fifty-five tagging single nucleotide polymorphisms covering genes encoding two IL12 subunits, IL12A and IL12B, and its receptors, IL12RB1 and IL12RB2, were examined in a cohort of 913 children residing in Asembo Bay region of western Kenya.

Results

An increasing copy number of minor variant (C) in IL12A (rs2243140) was significantly associated with a decreased risk of SMA (P = 0.006; risk ratio, 0.52 for carrying one copy of allele C and 0.28 for two copies). Individuals possessing two copies of a rare variant (C) in IL12RB1 (rs429774) also appeared to be strongly protective against SMA (P = 0.00005; risk ratio, 0.18). In addition, children homozygous for another rare allele (T) in IL12A (rs22431348) were associated with reduced risk of severe anaemia (SA) (P = 0.004; risk ratio, 0.69) and of severe anaemia with any parasitaemia (SAP) (P = 0.004; risk ratio, 0.66). In contrast, AG genotype for another variant in IL12RB1 (rs383483) was associated with susceptibility to high-density parasitaemia (HDP) (P = 0.003; risk ratio, 1.21).

Conclusions

This study has shown strong associations between polymorphisms in the genes of IL12A and IL12RB1 and protection from SMA in Kenyan children, suggesting that human genetic variants of IL12 related genes may significantly contribute to the development of anaemia in malaria patients.

Multilocus sequence typing and genetic structure of Cryptosporidium hominis from children in Kolkata, India☆

Endemicity of cryptosporidiosis in India has been documented with little genetic characterization of the parasites. Fifty Cryptosporidium-positive specimens collected between 2001 and 2004 from pediatric patients in Kolkata, India were analyzed for parasite genetic structure using multilocus sequence typing (MLST). Genotype analyses showed the presence of Cryptosporidium hominis, Cryptosporidium meleagridis and Cryptosporidium felis in 49, 2 and 1 patients, respectively (two patients had mixed infections of C. hominis and C. meleagridis). To assess the extent of genetic heterogeneity of C. hominis, minisatellites, microsatellites and polymorphic markers in three different chromosomes were sequenced, including genes encoding the 60kDa glycoprotein (GP60), a 47kDa protein (CP47), a mucin-like protein (Mucin1), a serine repeat antigen (MSC6-7), and a 56kDa trans-membrane protein (CP56) in chromosome 6, the 70kDa heat shock protein (HSP70) in chromosome 2, and a T-rich gene fragment (Chrom3T) in chromosome 3. Population sub-structure of C. hominis based on multilocus gene sequences showed that there were 25 multilocus subtypes defined by combined sequence length and nucleotide polymorphism, which formed four distinct groups in this population. Significant intra- and inter-genic linkage disequilibria were observed with minimum recombination or expansion of limited subtypes, all indicative of a mostly clonal population structure. The results highlight the importance of high resolution MLST in studying Cryptosporidium population sub-structure especially when length polymorphism may be inadequate in identifying unique subtypes. The significance of the diverse MLST within C. hominis in relation to geographical and temporal factors and clinical manifestations of disease warrants further investigations.

Evaluation of various methods of maternal placental blood collection for immunology studies

The collection of maternal placental intervillous blood (IVB), without contamination of fetal blood and with an accurate mononuclear cell profile, is essential for immunological studies of placental malaria and other infectious diseases of the placenta. We have compared five documented methods of IVB collection: perfusion, incision, biopsy, tissue grinding, and puncture (prick) for fetal blood contamination and mononuclear cell profiles using flow cytometry. Twenty-five placentas were obtained from Plasmodium falciparum and human immunodeficiency virus-negative primigravid and secundigravid women delivering at Nyanza Provincial Hospital in Kisumu, western Kenya. Each of the five methods was performed on the same placenta. Fetal red blood cell contamination was significantly lower for the prick and perfusion methods (4.1% and 8.3%, respectively) than for incision (59.5%), biopsy (42.6%), and tissue grinding (19.9%). Significant variation was noted among the five methods in the percentages of monocytes, total T cells, CD4+ and CD8+ T cells, B cells, and NK cells. Further, a pairwise comparison of prick and perfusion, the two methods with low fetal blood contamination, showed that they were not different for fetal red blood cell contamination levels; however, prick yielded significantly higher percentages of CD4 T cells and CD4 memory T cells than perfusion. Collection by prick was determined to be the best method of intervillous blood collection for immunology studies, and perfusion represented the next best method of choice due to high sample volume yield. Overall, in considering the advantages/disadvantages of the two methods with low fetal cell contamination, we conclude that a combination of prick and perfusion is most suitable for immunology studies.

A comparative study of the genetic diversity of the 42kDa fragment of the merozoite surface protein 1 in Plasmodium falciparum and P. vivax

We investigated the genetic diversity of the 42kDa fragment of the merozoite surface protein 1 (MSP-1) antigen in Plasmodium falciparum and P. vivax, as well as in non-human primate malarial parasites. This fragment undergoes a proteolytic cleavage generating two fragments of 19kDa (MSP-1(19)) and 33kDa (MSP-1(33)) that are critical in erythrocyte invasion. We found that overall the MSP-1(33) fragment exhibits greater genetic diversity than the MSP-1(19) regardless of the species. We have found evidence for positive natural selection only in the human malaria parasites by comparing the rate of non-synonymous versus synonymous substitutions. In addition, we found clear differences between the two major human malaria parasites. In the case of P. falciparum, positive natural selection is acting on the MSP-1(19) region while the MSP-1(33) is neutral or under purifying selection. The opposite pattern was observed in P. vivax. Our results suggest different roles of this antigen in the host-parasite immune interaction in each of the major human malarial parasites.

Molecular characterization of Cryptosporidium spp. from children in Kolkata, India

The intracellular parasite Cryptosporidium is responsible for severe diarrhea in immunocompromised persons in developing countries. Few studies on the characterization of the parasite in India are available. In this study, molecular characterization of the parasite from diarrheic children was carried out by PCR-restriction fragment length polymorphism analysis. At least three genotypes were identified. Out of 40 positive samples, 35 were positive for C. hominis, 4 were positive for C. parvum, and 1 was positive for C. felis. This study clearly suggests that cryptosporidiosis in this region is caused largely by anthroponotic transmission.

Genetic diversity in the Block 2 region of the merozoite surface protein 1 (MSP-1) of Plasmodium falciparum: additional complexity and selection and convergence in fragment size polymorphism

Fragment size in the Block 2 repetitive region of merozoite surface protein 1 (MSP1) has commonly been used as a molecular marker in studies of malaria transmission dynamics and host immunity in Plasmodium falciparum malaria. In this study, we further explore the genetic variation in MSP-1 Block 2 underlying potential problems faced while studying the immune responses elicited by this vaccine target and while using it as a molecular marker in epidemiologic investigations. We describe the distribution of a new Block 2 recombinant allele family in samples collected from western Kenya and other malarious regions of the world and provide evidence that this allele family is found worldwide and that all MR alleles most likely originated from a single recombination event. We test whether the number of tandem repeats (i.e. fragment size) can be considered neutral in an area of high transmission in western Kenya. In addition, we investigate the validity of the assumption that Block 2 alleles of the same size and allele family are identical by examining MSP1 Block 2 amino acid sequences obtained from full-length MSP-1 clones generated from infected Kenyan children and find that this assumption does not hold. We conclude that the worldwide presence of a new allele family, the effect of positive natural selection, and the lack of conserved amino acid motifs within alleles of the same size suggest a higher level of complexity that may hamper our ability to elucidate allele family specific immune responses elicited by this vaccine target and its overall use as genetic marker in other types of epidemiologic investigations.

Preliminary observations on the efficacy of a recombinant multistage Plasmodium falciparum vaccine in Aotus nancymai monkeys

A vaccine trial was conducted to determine the efficacy of a multicomponent candidate vaccine, FALVAC-1, against Plasmodium falciparum in Aotus nancymai monkeys. After two immunizations, animals were challenged intravenously with parasites of the Vietnam Oak Knoll (FVO) strain of P. falciparum. The primary outcome was to determine the protective response of the monkeys to immunization with the FALVAC-1 antigen produced in baculovirus when combined with different adjuvants (alum, QS-21, ASO2a, CRL1005/oil, and CRL1005/saline) as compared with FALVAC-1 with FCA/FIA and antigen alone. When compared with the monkeys immunized with FALVAC-1 alone, FALVAC-1 with FCA/FIA reduced the mean parasite count (to Day 11), reduced the mean accumulated parasitemia (through Day 11), and extended the number of days to treatment. None of the other 5 antigen-adjuvant combinations were able to provide discernable levels of protection based on log(parasitemia) and log(cumulative parasitemia) to Day 11.

Effect of CCR2 chemokine receptor polymorphism on HIV type 1 mother-to-child transmission and child survival in Western Kenya

The effect of CCR2 polymorphism on HIV-1 mother-to-child transmission and disease progression has not been explored in depth within Africa. As the CCR2-64I variant of this putative HIV coreceptor has been associated with slower progression to AIDS in adults, the current study was undertaken to examine the relationship between CCR2 polymorphism and HIV-1 perinatal transmission and child survival in western Kenya. CCR2 genotype was determined for 445 HIV-seropositive mothers and their infants. The CCR2-64I allele frequency of both mothers and children did not differ by HIV-1 transmission status, regardless of maternal viral load, viral subtype, immune status, or placental malaria status. For infants who acquired HIV perinatally (n = 78), there was no association between CCR2 genotype and viral load upon infection or survival rate over the 2-year follow-up. Our results do not indicate an effect of CCR2-64I on perinatal HIV transmission and survival in Kenyan children.

A monkey's tale: the origin of Plasmodium vivax as a human malaria parasite

The high prevalence of Duffy negativity (lack of the Duffy blood group antigen) among human populations in sub-Saharan Africa has been used to argue that Plasmodium vivax originated on that continent. Here, we investigate the phylogenetic relationships among 10 species of Plasmodium that infect primates by using three genes, two nuclear (beta-tubulin and cell division cycle 2) and a gene from the plastid genome (the elongation factor Tu). We find compelling evidence that P. vivax is derived from a species that inhabited macaques in Southeast Asia. Specifically, those phylogenies that include P. vivax as an ancient lineage from which all of the macaque parasites could originate are significantly less likely to explain the data. We estimate the time to the most recent common ancestor at four neutral gene loci from Asian and South American isolates (a minimum sample of seven isolates per locus). Our analysis estimates that the extant populations of P. vivax originated between 45,680 and 81,607 years ago. The phylogeny and the estimated time frame for the origination of current P. vivax populations are consistent with an "out of Asia" origin for P. vivax as hominoid parasite. The current debate regarding how the Duffy negative trait became fixed in Africa needs to be revisited, taking into account not only human genetic data but also the genetic diversity observed in the extant P. vivax populations and the phylogeny of the genus Plasmodium.

Genetic Distance in Housekeeping Genes Between Plasmodium falciparum and Plasmodium reichenowi and Within P. falciparum

The time to the most recent common ancestor of the extant populations of Plasmodium falciparum is controversial. The controversy primarily stems from the limited availability of sequences from Plasmodium reichenowi, a chimpanzee malaria parasite closely related to P. falciparum. Since the rate of nucleotide substitution differs in different loci and DNA regions, the estimation of genetic distance between P. falciparum and P. reichenowi should be performed using orthologous sequences that are evolving neutrally. Here, we obtained full-length sequences of two housekeeping genes, sarcoplasmic and endoplasmic reticulum Ca2+ -ATPase (serca) and lactate dehydrogenase (ldh), from 11 isolates of P. falciparum and 1 isolate of P. reichenowi and estimate the interspecific genetic distance (divergence) between the two species and intraspecific genetic distance (polymorphism) within P. falciparum. Interspecific distance and intraspecific distance at synonymous sites of interspecies-conserved regions of serca and ldh were 0.0672 +/- 0.0088 and 0.0011 +/- 0.0007, respectively, using the Nei and Gojobori method. Based on the ratio of interspecific distance to intraspecific distance, the time to the most recent common ancestor of P. falciparum was estimated to be (8.30 +/- 5.40) x 10(4) and (11.62 +/- 7.56) x 10(4) years ago, assuming the divergence time of the two parasite species to be 5 and 7 million years ago, respectively.

Enhanced expression of a recombinant malaria candidate vaccine in Escherichia coli by codon optimization

This study was conducted to compare the expression of three constructs of a multistage candidate vaccine (FALVAC-1) against Plasmodium falciparum in an Escherichia coli system: a synthetic gene with P. falciparum codons, a synthetic gene with optimized E. coli codons, and a synthetic gene with P. falciparum codons co-transformed with a RIG plasmid, which encodes three tRNAs (AG(A/G), ATA, GGA) that recognize rare E. coli codons. The expression of the protein increased at least threefold with codon optimization. The presence of the RIG plasmid in the co-transforming cells did not significantly increase the expression level of the gene with P. falciparum codons. The growth of cells transformed by the construct with P. falciparum codons was significantly slower than that of cells transformed by the construct with optimized E. coli codons after induction of protein expression with IPTG. The cells containing the non-codon optimized gene co-expressed with RIG plasmid had the slowest growth at all time points in culture. Thus, codon optimization significantly increases the yield of P. falciparum candidate vaccines in the E. coli expression system.

Detection and differentiation of Cryptosporidium oocysts in water by PCR-RFLP

Consumption of contaminated water has been implicated as a major source of Cryptosporidium infection in various outbreak investigations and case control studies. Surveys conducted in various regions of the United States demonstrated the presence of Cryptosporidium oocysts in 67-100% of wastewaters, 24-100% of surface waters, and 17-26.8% of drinking waters. The identity and human infective potential of these waterborne oocysts are not known, although it is likely that not all oocysts are from human-infecting Cryptosporidium species. Likewise, the source of the oocyst contamination is also not fully clear. Farm animals and human sewage discharge are generally considered to be the major sources of surface water contamination with C. parvum. Because Cryptosporidium infection is common in wildlife, it is conceivable that wildlife can also be a source for Cryptosporidium oocysts in waters. The presence of host-adapted Cryptosporidium spp. and genotypes makes it possible to develop molecular tools to assess the human infection potential and source of Cryptosporidium oocysts in water.Currently, the identification of Cryptosporidium oocysts in environmental samples is largely made by the use of immunofluorescent assay (IFA) after concentration processes (Environmental Protection Agency [EPA] recommended information collection rule [ICR] method or method 1622/1623 or similar techniques). Because IFA detects oocysts from all Cryptosporidium parasites, the species distribution of Cryptosporidium parasites in environmental samples cannot be assessed. Although many surface water samples contain Cryptosporidium oocysts, it is unlikely that all these oocysts are from human-pathogenic species or genotypes, because only five genotypes of Cryptosporidium parasites (the C. parvum human and bovine genotypes, C. meleagridis, C. canis, and C. felis) are responsible for most human infections. Information on the source of C. parvum contamination is necessary for effective evaluation and selection of management practices for reducing C. parvum contamination of surface water and the risk of cryptosporidiosis. Thus, identification of oocysts to species and genotype levels is of public health importance.

Polymorphism of Fc receptor IIa for immunoglobulin G is associated with placental malaria in HIV-1-positive women in western Kenya

BACKGROUND

Genetic polymorphism of the Fc receptor IIa for immunoglobulin (Ig) G (Fc gamma RIIa) determines IgG subclass binding. Previous studies have shown that individuals with the IgG1/3-binding Fc gamma RIIa-Arg/Arg131 genotype are relatively protected against high-density malaria, whereas individuals with the IgG2-binding Fc gamma RIIa-His/His131 genotype are at increased risk for developing cerebral malaria. The present study was undertaken to examine the relationship between Fc gamma RIIa polymorphism and placental malaria (PM) in pregnant women of known human immunodeficiency virus (HIV)-1 status.

METHODS

Fc gamma RIIa genotype was determined in 903 pregnant women who had participated in a study designed to assess the effect that PM has on vertical transmission of HIV-1. Fc gamma RIIa polymorphism was assessed in relation to PM.

RESULTS

Among HIV-negative women, there was no difference in the distribution of the Fc gamma RIIa polymorphism by PM status. However, among HIV-positive women, the frequency of the Fc gamma RIIa-His/His131 genotype was significantly higher in women with PM than in women without PM (31% vs. 22%, respectively [P=.032]). In multivariate analysis, the adjusted odds ratio for PM in HIV-positive women with the Fc gamma RIIa-His/His131 genotype versus women in the Fc gamma RIIa-His/Arg131 reference group was 1.72 (95% confidence interval, 1.11-2.69 [P=.016]).

CONCLUSIONS

The present study suggests that the IgG2-binding Fc gamma RIIa-His/His131 genotype is associated with enhanced susceptibility to PM in HIV-positive women but not in HIV-negative women.

Assessing the effect of natural selection in malaria parasites

There are few concepts that have been used across disciplines; one of them is natural selection. The impact that this process has on parasite genetic diversity is reviewed here by discussing examples on drug resistance and vaccine antigens. Emphasis is made on how mechanisms need to be addressed rather than associations, and how such investigations were out of reach of biomedical researchers only a decade ago.

Genetic diversity of Cryptosporidium spp. in captive reptiles

The genetic diversity of Cryptosporidium in reptiles was analyzed by PCR-restriction fragment length polymorphism and sequence analysis of the small subunit rRNA gene. A total of 123 samples were analyzed, of which 48 snake samples, 24 lizard samples, and 3 tortoise samples were positive for Cryptosporidium: Nine different types of Cryptosporidium were found, including Cryptosporidium serpentis, Cryptosporidium desert monitor genotype, Cryptosporidium muris, Cryptosporidium parvum bovine and mouse genotypes, one C. serpentis-like parasite in a lizard, two new Cryptosporidium spp. in snakes, and one new Cryptosporidium sp. in tortoises. C. serpentis and the desert monitor genotype were the most common parasites and were found in both snakes and lizards, whereas the C. muris and C. parvum parasites detected were probably the result of ingestion of infected rodents. Sequence and biologic characterizations indicated that the desert monitor genotype was Cryptosporidium saurophilum. Two host-adapted C. serpentis genotypes were found in snakes and lizards.

Polymorphism of Fc receptor IIa for IgG in infants is associated with susceptibility to perinatal HIV-1 infection

OBJECTIVE

To evaluate the effect of polymorphism of the Fc gamma receptor IIa, which is associated with differential human IgG subclass binding, on perinatal HIV-1 transmission.

METHODS

Fc gamma RIIa genotype was tested in 448 HIV-seropositive mothers and their infants from a cohort study designed to assess the effect of placental malaria on HIV vertical transmission conducted from 1996 to 2001 in western Kenya. Fc gamma RIIa polymorphism was analyzed for associations with susceptibility to perinatal HIV infection and all-cause child mortality in HIV-positive children.

RESULTS

Overall, 20% of infants were perinatally infected with HIV. There was no statistically significant association between maternal genotype and perinatal HIV-1 transmission. However, frequency of the infant Fc gamma RIIa His/His131 genotype was higher in HIV-positive compared with HIV-negative infants (35% and 21%, respectively), whereas the distribution was reversed (15% and 28%, respectively) for infants with the Fc gamma RIIa Arg/Arg131 genotype. Multivariate logistic regression controlling for maternal and infant confounding factors demonstrated that the odds of perinatal HIV infection in infants with the Fc gamma RIIa His/His131 versus Fc gamma RIIa His/Arg131 genotypes were significantly higher (adjusted odds ratio, 2.22; 95% confidence interval, 1.23-4.02; P = 0.009). There was no evidence for an association between HIV-positive child all-cause mortality and Fc gamma RIIa genotype.

CONCLUSIONS

This study provides the first evidence that the infant Fc gamma RIIa His/His131 genotype is associated with susceptibility to perinatal HIV-1 transmission and further suggests that there is a dose-response relationship for the effect of the Fc gamma RIIa His131 gene on transmission.

Triosephosphate isomerase gene characterization and potential zoonotic transmission of Giardia duodenalis

To address the source of infection in humans and public health importance of Giardia duodenalis parasites from animals, nucleotide sequences of the triosephosphate isomerase (TPI) gene were generated for 37 human isolates, 15 dog isolates, 8 muskrat isolates, 7 isolates each from cattle and beavers, and 1 isolate each from a rat and a rabbit. Distinct genotypes were found in humans, cattle, beavers, dogs, muskrats, and rats. TPI and small subunit ribosomal RNA (SSU rRNA) gene sequences of G. microti from muskrats were also generated and analyzed. Phylogenetic analysis on the TPI sequences confirmed the formation of distinct groups. Nevertheless, a major group (assemblage B) contained most of the human and muskrat isolates, all beaver isolates, and the rabbit isolate. These data confirm that G. duodenalis from certain animals can potentially infect humans and should be useful in the detection, differentiation, and taxonomy of Giardia spp.