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The conventional paper-based system for malaria surveillance is time-consuming, difficult to track and resource-intensive. Few digital platforms are in use but wide-scale deployment and acceptability remain to be seen. To address this issue, we created a malaria surveillance mobile app that offers real-time data to stakeholders and establishes a centralised data repository. The MoSQuIT app was designed to collect data from the field and was integrated with a web-based platform for data integration and analysis. The MoSQuIT app was deployed on mobile phones of accredited social health activists (ASHA) working in international border villages in the northeast (NE) Indian states of Assam, Tripura and Arunachal Pradesh for 20 months in a phased manner. This paper shares the challenges and opportunities associated with the use of MoSQuIT for malaria surveillance. MoSQuIT employs the same data entry formats as the NVBDCP's malaria surveillance programme. Using this app, a total of 8221 fever cases were recorded, which included 1192 (14.5%) cases of P. falciparum malaria, 280 (3.4%) cases of P. vivax malaria and 52 (0.6%) mixed infection cases. Depending on network availability, GPS coordinates of the fever cases were acquired by the app. The present study demonstrated that mobile-phone-based malaria surveillance facilitates the quick transmission of data from the field to decision makers. Geospatial tagging of cases helped with easy visualisation of the case distribution for the identification of malaria-prone areas and potential outbreaks, especially in hilly and remote regions of Northeast India. However, to achieve the full operational potential of the system, operational challenges have to be overcome.

Background: Malaria continues to be a major public health problem in the Northeastern part of India despite the implementation of vector control measures and changes in drug policies. To develop successful vaccines against malaria, it is important to assess the diversity of vaccine candidate antigens in field isolates. This study was done to assess the diversity of Plasmodium falciparum AMA-1 vaccine candidate antigen in a malaria-endemic region of Tripura in Northeast India and compare it with previously reported global isolates with a view to assess the feasibility of developing a universal vaccine based on this antigen., Methods: Patients with fever and malaria-like illness were screened for malaria and P. falciparum positive cases were recruited for the current study. The diversity of PfAMA-1 vaccine candidate antigen was evaluated by nested PCR and RFLP. A selected number of samples were sequenced using the Sanger technique., Results: Among 56 P. falciparum positive isolates, Pfama-1 was successfully amplified in 75% (n = 42) isolates. Allele frequencies of PfAMA-1 antigen were 16.6% (n = 7) for 3D7 allele and 33.3% (n = 14) in both K1 and HB3 alleles. DNA sequencing revealed 13 haplotypes in the Pfama-1 gene including three unique haplotypes not reported earlier. No unique amino-acid substitutions were found. Global analysis with 2761 sequences revealed 435 haplotypes with a very complex network composition and few clusters. Nucleotide diversity for Tripura (0.02582 ± 0.00160) showed concordance with South-East Asian isolates while recombination parameter (Rm = 8) was lower than previous reports from India. Population genetic structure showed moderate differentiation., Conclusions: Besides documenting all previously reported allelic forms of the vaccine candidate PfAMA-1 antigen of P. falciparum, new haplotypes not reported earlier, were found in Tripura. Neutrality tests indicate that the Pfama-1 population in Tripura is under balancing selection. This is consistent with global patterns. However, the high haplotype diversity observed in the global Pfama-1 network analysis indicates that designing a universal vaccine based on this antigen may be difficult. This information adds to the existing database of genetic diversity of field isolates of P. falciparum and may be helpful in the development of more effective vaccines against the parasite., (© 2022. The Author(s).)

Artemisinin-based combination therapy (ACT) has been used to treat uncomplicated Plasmodium falciparum infections in India since 2004. Since 2008, a decrease in artemisinin effectiveness has been seen throughout the Greater Mekong Subregion. The geographic proximity and ecological similarities of northeastern India to Southeast Asia may differentially affect the long-term management and sustainability of ACT in India. In order to collect baseline data on variations in ACT sensitivity in Indian parasites, 12 P. falciparum isolates from northeast India and 10 isolates from southwest India were studied in vitro Ring-stage survival assay (RSA) showed reduced sensitivity to dihydroartemisinin in 50% of the samples collected in northeast India in 2014 and 2015. Two of the 10 assayed samples from the southwest region of India from as far back as 2012 also showed decreased sensitivity to artemisinin. In both these regions, kelch gene sequences were not predictive of reduced artemisinin sensitivity, as measured by RSA. The present data justify future investments in integrated approaches involving clinical follow-up studies, in vitro survival assays, and molecular markers for tracking potential changes in the effectiveness of artemisinin against P. falciparum throughout India., (Copyright © 2019 Chakrabarti et al.)

Malaria remains a significant public health challenge and is of global importance. Imported malaria is a growing problem in non-endemic areas throughout the world and also in Qatar due to a massive influx of migrants from endemic countries. Antimalarial drug resistance is an important deterrent in our fight against malaria today. Molecular markers mirror intrinsic antimalarial drug resistance and their changes precede clinical resistance. Thus, in the present study, molecular markers of sulphadoxine-pyrimethamine ( Pfdhfr and Pfdhps ) and artemisinin ( PfATPase6 and Pfk13 ) were sequenced to determine the drug resistance genotypes among 118 imported P. falciparum isolates in Qatar, between 2013 and 2016. All the isolates had mutant Pfdhfr alleles, with either double mutant (51I/108N) (59.3%) or triple mutant (51I, 59R and 108N) (30.6%) genotypes. I164L substitution was not found in this study. In case of Pfdhps , majority of the samples were carriers of either single (S436A/ A437G/ K540E) mutant (47.2%) or double (S436A/K540E, A437G/K540E, K540E/A581G) mutant (39.8%). A single novel point mutation (431V) was observed in the samples originated from Nigeria and Ghana. Polymorphisms in PfATPase6 were absent and only one non-synonymous mutation in Pfk13 was found at codon G453A from a sample of Kenyan origin. High levels of sulphadoxine-pyrimethamine resistance in the present study provide potential information about the spread of antimalarial drug resistance and will be beneficial for the treatment of imported malaria cases in Qatar.

Imported malaria has been a great challenge for public health in Qatar due to influx of large number of migrant workers. Antimalarial drug resistance has emerged as one of the greatest challenges facing malaria control today. Monitoring parasite haplotypes that predict susceptibility to major antimalarial can guide treatment policies. This study aimed to determine molecular drug resistance pattern in imported malaria cases in Qatar. Blood samples from the uncomplicated P. falciparum malaria patients were collected at Hamad General Hospital, HMC, Doha, Qatar. The samples were further confirmed by nested-polymerase chain reaction (PCR) for P. falciparum. Molecular markers of chloroquine (Pfcrt and Pfmdr1) were analyzed by using nested PCR- RFLP method to determine the key point mutations associated with chloroquine (CQ) drug resistance. A total 118 blood samples were positive for P. falciparum. Overall, by RFLP, 72% harboured wild type allele (N86) of Pfmdr1 gene. The prevalence of Pfcrt mutant (T76), WT (K76) and mixed alleles (K76T) was 63.6% (n = 75), 22.9% (n = 27) and 13.5% (n = 16), respectively. Mean parasitaemia level was higher among the wild type alleles of Pfcrt gene as compared to the mixed/mutant alleles whereas mixed alleles of Pfmdr1 gene having high parasitaemia. Molecular surveillance strategy based on imported malaria cases can be used to detect and track CQ drug-resistant malaria. The data presented here might be helpful for enrichment of molecular surveillance of antimalarial resistance and will be useful for developing and updating antimalarial guidance for non-immune imported cases in Qatar.

Objective: To elucidate the genetic diversity of Plasmodium falciparum in residual transmission foci of northern India., Methods: Clinically suspected patients with malaria were screened for malaria infection by microscopy. 48 P. falciparum-infected patients were enrolled from tertiary care hospital in Chandigarh, India. Blood samples were collected from enrolled patients, genomic DNA extraction and nested PCR was performed for further species confirmation. Sanger sequencing was carried out using block 2 region of msp1, R2 region of glurp and pfs25-specific primers., Results: Extensive diversity was found in msp1 alleles with predominantly RO33 alleles. Overall allelic prevalence was 55.8% for RO33, 39.5% for MAD20 and 4.7% for K1. Six variants were observed in MAD20, whereas no variant was found in RO33 and K1 alleles. A phylogenetic analysis of RO33 alleles indicated more similarity to South African isolates, whereas MAD20 alleles showed similarity with South-East Asian isolates. In glurp, extensive variation was observed with eleven different alleles based on the AAU repeats. However, pfs25 showed less diversity and was the most stable among the targeted genes., Conclusion: Our findings document the genetic diversity among circulating strains of P. falciparum in an area of India with low malaria transmission and could have implications for control strategies to reach the national goal of malaria elimination., (© 2017 John Wiley & Sons Ltd.)

Malaria is a major public health concern in Northeast India with a preponderance of drug-resistant strains. Until recently the partner drug for artemisinin combination therapy (ACT) was sulphadoxine pyrimethamine (SP). Antifolate drug resistance has been associated with the mutations at dihydropteroate synthase (dhps) and dihydrofolatereductase (dhfr) genes. This study investigated antifolate drug resistance at the molecular level. A total of 249 fever cases from Arunachal Pradesh, NE India, were screened for malaria, and of these, 75 were found to be positive for Plasmodium falciparum . Samples were sequenced and analysed with the help of BioEdit and ClustalW. Three novel point mutations were found in the dhps gene with 10 haplotypes along with the already reported mutations. A single haplotype having quadruple mutation was found in the dhfr gene. The study reports higher degree of antifolate drug resistance as evidenced by the presence of multiple point mutations in dhps and dhfr genes. The findings of this study strongly discourage the use SP as a partner drug in ACT.

Antimalarial drug resistance is a major global challenge in malaria control and elimination. Mutations in six different genes of Plasmodium falciparum (crt, mdr1, dhfr, dhps, ATPase6 and K-13 propeller) that confer resistance to chloroquine, sulphadoxine-pyrimethamine and artemisinin-based combination therapy were analyzed in samples from Chhattisgarh. Seventy-eight percent of the samples were found to have a pfcrt mutation (53% double, 24% triple and 1% single mutant), and 59% of pfmdr1 genes were found to have an N86Y mutation. Double mutations were recorded in pfdhfr gene among 76% of the samples while only 6% of the samples harbored mutant genotypes in pfdhps. No mutation was found in the K-13 propeller gene, while only one sample showed a mutant genotype for the PfATPase6 gene. The Tajima test confirmed that there is no role of evolutionary natural selection in drug resistance, and gene pairwise linkage of disequilibrium showed significant intragenic association. The high level of pfcrt mutations suggests that parasite resistance to chloroquine is almost at a fixed level, whereas resistance to SP is evolving in the population and parasites remain sensitive to artemisinin derivatives. These findings provide potential information and understanding of the evolution and spread of different drug resistance alleles in Chhattisgarh.

Background & Objectives: Northeast (NE) India is one of the high endemic regions for malaria with a preponderance of Plasmodium falciparum, resulting in high morbidity and mortality. The P. falciparum parasite of this region showed high polymorphism in drug-resistant molecular biomarkers. However, there is a paucity of information related to merozoite surface protein 1 (msp-1) and glutamate-rich protein (glurp) which have been extensively studied in various parts of the world. The present study was, therefore, aimed at investigating the genetic diversity of P. falciparum based on msp-1 and glurp in Arunachal Pradesh, a State in NE India., Methods: Two hundred and forty nine patients with fever were screened for malaria, of whom 75 were positive for P. falciparum. Blood samples were collected from each microscopically confirmed patient. The DNA was extracted; nested polymerase chain reaction and sequencing were performed to study the genetic diversity of msp-1 (block 2) and glurp., Results: The block 2 of msp-1 gene was found to be highly polymorphic, and overall allelic distribution showed that RO33 was the dominant allele (63%), followed by MAD20 (29%) and K1 (8%) alleles. However, an extensive diversity (9 alleles and 4 genotypes) and 6-10 repeat regions exclusively of R2 type were observed in glurp., Interpretation & Conclusions: The P. falciparum population of NE India was diverse which might be responsible for higher plasticity leading to the survival of the parasite and in turn to the higher endemicity of falciparum malaria of this region.

Background & Objectives: The interactions between HIV and malaria co-infection have been shown to influence each other in their clinical outcomes in Sub-Saharan Africa. This study was carried out in the two States of north east India endemic for both HIV and malaria infections, to study the interactions between the two diseases in the HIV-infected population., Methods: In this prospective study, a total of 333 HIV-infected individuals were followed up for a period of 6-18 months in Mizoram and Manipur during 2010-2011. The study assessed the changes in viral load and also the therapeutic efficacy of artesunate plus sulphadoxine-pyrimethamine (AS+SP) combination therapy in HIV-infected and HIV-uninfected individuals with Plasmodium falciparum malaria., Results: Viral load in HIV-infected malaria patients on day zero (D0) ranged from 1110 to 147,000 copies/ml. The log transformation of the geometric means of HIV viral loads revealed no significant difference on different days of follow up. There was 100 per cent adequate clinical and parasitological response (ACPR) after treating with artemisinin based combination therapy (ACT) both in HIV-infected and HIV-uninfected P. falciparum-positive individuals. Similarly, chloroquine showed 100 per cent ACPR in P. vivax HIV-infected individuals., Interpretation & Conclusion: The study showed no significant increase in HIV viral load in malaria cases. All HIV-infected and HIV-uninfected P. falciparum malaria-positive cases responded to the treatment with 100 per cent ACPR.

North-east India, being a corridor to South-east Asia, is believed to play an important role in transmitting drug resistant Plasmodium falciparum malaria to India and South Asia. North-east India was the first place in India to record the emergence of drug resistance to chloroquine as well as sulphadoxine/pyrimethamine. Presently chloroquine resistance is widespread all over the North-east India and resistance to other anti-malarials is increasing. In this study both in vivo therapeutic efficacy and molecular assays were used to screen the spectrum of drug resistance to chloroquine and sulphadoxine/pyrimethamine in the circulating P. falciparum strains. A total of 220 P. falciparum positives subjects were enrolled in the study for therapeutic assessment of chloroquine and sulphadoxine/pyrimethamine and assessment of point mutations conferring resistances to these drugs were carried out by genotyping the isolates following standard methods. Overall clinical failures in sulphadoxine/pyrimethamine and chloroquine were found 12.6 and 69.5% respectively, while overall treatment failures recorded were 13.7 and 81.5% in the two arms. Nearly all (99.0%) the isolates had mutant pfcrt genotype (76 T), while 68% had mutant pfmdr-1 genotype (86 Y). Mutation in dhps 437 codon was the most prevalent one while dhfr codon 108 showed 100% mutation. A total of 23 unique haplotypes at the dhps locus and 7 at dhfr locus were found while dhps-dhfr combined loci revealed 49 unique haplotypes. Prevalence of double, triple and quadruple mutations were common while 1 haplotype was found with all five mutated codons (F/AGEGS/T) at dhps locus. Detection of quadruple mutants (51 I/59 R/108 N/164 L) in the present study, earlier recorded from Car Nicobar Island, India only, indicates the presence of high levels of resistance to sulphadoxine/pyrimethamine in north-east India. Associations between resistant haplotypes and the clinical outcomes and emerging resistance in sulphadoxine/pyrimethamine in relation to the efficacy of the currently used artemisinin combination therapy are discussed.

Background & Objectives: Severe anaemia in Plasmodium falciparum (Pf) associated malaria is a leading cause of death despite low levels of parasitaemia. In an effort to understand the pathogenesis of anaemia we studied expression level of RBC complement regulatory proteins, CR1 (CD35), CD55 and CD59 with haemoglobin status in a group of malaria cases from Assam, Goa and Chennai, and in healthy controls., Methods: Flowcytometry was used to study expression of CR1, CD55 and CD59 in 50 Pf cases and 30 normal healthy volunteers. Giemsa stained thick and thin blood films were used for microscopic detection and identification of malarial parasites and parasite count., Results: No correlation was found between degree of expression of RBC surface receptors CR1, CD55 and CD59 with haemoglobin level. However, expression of CD55 was less in malaria cases than in healthy controls., Interpretation & Conclusions: The present findings indicate that malaria infection changes the expression profile of complement regulatory protein CD55 irrespective of severity status of anaemia. Further studies are needed to explore the pathophysiology of anaemia in malaria cases in Assam where expression of RBC complement receptors appears to be low even in normal healthy population.

The Anopheles philippinensis and An. nivipes mosquitoes that form part of the An. annularis species group are morphologically very similar and difficult to differentiate as adults. In consequence, researchers generally refer to all field-collected individuals of these species simply as the An. philippinensis-nivipes species complex. Although this species complex is understood to play a role in the transmission of parasites causing human malaria in north-eastern India, the identity of the exact species involved, and the relative importance of the local An. philippinensis and An. nivipes, are far from clear. To settle this issue, house-frequenting female adults of the An. philippinensis-nivipes species complex were collected from 23 localities in the six north-eastern states, identified to species (using an allele-specific PCR to explore the insects' ribosomal-DNA internal-transcribed-spacer-2 sequences) and checked for Plasmodium DNA (using a nested PCR based on the 18S subunit of the parasite's ribosomal DNA). Of the 337 females of the An. philippinensis-nivipes species complex that were investigated, 275 were identified as An. nivipes and 62 as An. philippinensis. Malarial infection was detected in the heads/thoraces of just two specimens, with P. falciparum DNA detected in one An. nivipes from Nagaland state and one An. nivipes from Assam state. These results provide unambiguous evidence of the presence of both An. philippinensis and An. nivipes in the north-eastern region of India and the involvement of An. nivipes in transmitting P. falciparum in this area.

Chloroquine (CQ) and sulphadoxine/pyrimethamine (SP) are two first-line antimalarials used under the existing Indian National Drug Policy in the north-eastern region of India bordering several countries including Myanmar. Although widespread resistance to antimalarials in Plasmodium falciparum has been reported from western Myanmar, information from the Indian side of the border is scarce. We studied the therapeutic response to CQ and SP at four sites in Changlang and Lohit, two administrative districts of Arunachal Pradesh bordering Myanmar. We monitored uncomplicated falciparum malaria patients after treatment with standard regimens of CQ and SP for 28 days following the revised in-vivo protocol of the World Health Organization. A total of 236 patients, 95 in the CQ group and 141 in the SP group, participated. We recorded 23.8% early treatment failures to CQ and 14.1% to SP; late clinical failures of 14.3 and 12.6%; late parasitological failures of 10.7 and 8.1% and adequate clinical and parasitological responses of 51.2 and 65.2%, respectively. The significantly different treatment failure rates seen in Chowkham (furthest from Indo-Myanmar border) and Jairampur/Nampong (nearest to Indo-Myanmar border) for chloroquine (Cox proportion hazard ratio 9.1, P<0.0001) and SP (Cox proportion hazard ratio 7.35, P=0.001) denote a non-response gradient to the two antimalarials extending from the international border. The gradient is probably indicative of the direction of movement of the drug-resistant P. falciparum parasite. The utility of chloroquine as the first-line drug under the present National Drug Policy in these areas needs reconsideration.

In north-eastern India, Anopheles minimus, An. dirus and An. fluviatilis are considered the three major vectors of the parasites causing human malaria. The role in transmission of the other Anopheles species present in this region is not, however, very clear. To examine the vectorial role of the more common anopheline mosquitoes, the heads and thoraces of 4126 female Anopheles belonging to 16 species (collected using miniature light traps set in human dwellings in a foothill village in the Jorhat district of Assam state) were tested, in ELISA, for the circumsporozoite proteins (CSP) of Plasmodium falciparum or the VK-210 and VK-247 polymorphs of P. vivax. Sixty-five pools of head-thorax homogenates, representing 10 different species of Anopheles, were found reactive, giving an overall minimum prevalence of infection (MPI) of 1.58%, with a 95% confidence interval (CI) of 1.21%-2.0%. Among the CSP-reactive pools of mosquitoes, 31% were positive only for P. falciparum, 45% only for P. vivax VK 247, 6% only for P. vivax VK 210, and 18% for both P. falciparum and P. vivax VK 247. The results indicate that not only the proven vector, An. minimus s.l. (MPI = 0.71%), but also several species of Anopheles previously considered unimportant in the epidemiology of malaria, especially An. aconitus (MPI = 3.95%), An. annularis (MPI = 5.8%), the An. hyrcanus group (MPI = 0.48%), An. kochi (MPI = 1.28%), the An. philippinensis-nivipes complex (MPI = 0.94%), and An. vagus (MPI = 3.87%), are important vectors in the foothills of Assam.

Background & Objectives: Malaria is one of the major public health problems in the north eastern region of India. Antimalarial drug resistance is widespread and one of the important causes of recent resurgence of falciparum malaria in this region. Antimalarial drugs are seen to be used sequentially one after another in many areas of the region, when therapeutic failure is observed with a drug. In view of this, the present study was undertaken to assess the therapeutic efficacy of common antimalarial drugs viz., chloroquine, sulfadoxine+pyrimethamine (S-P) and quinine, administered sequentially to the patients with Plasmodium falciparum infection in a Myanmar bordering area of Arunachal Pradesh., Methods: A hospital based in vivo study was carried out with 53 patients with uncomplicated falciparum malaria. All patients were first treated with chloroquine and therapeutic efficacy assessed. In case of therapeutic failure of chloroquine combination drug (S-P) was given and those showing failure with S-P combination, oral quinine was administered and followed up for 28 days to assess both clinical and parasitological responses., Results: Therapeutic failure was observed with chloroquine in 83.1 per cent (44 of 53) and to both chloroquine and S-P combination drug in 44.1 per cent (19/43) patients. Further, 15.8 per cent patients (3 of 19) failed to respond even to quinine. Overall, 5.7 per cent patients (3 of 53) showed unresponsiveness to all the three drugs i.e., chloroquine, S-P combination and quinine. Asexual parasite clearance and also fever clearance was slowest with chloroquine and fastest with quinine., Interpretation & Conclusion: The findings of this study show the presence of multi drug failure P. falciparum in Jairampur-Nampong, a western Myanmar bordering area of Arunachal Pradesh. Anti malarial drug resistance is increasing in Indo-Myanmar border areas and systematic studies need to be done to review the situation.

Background: Assam, in north-east India, is extremely rich in hydrocarbon deposits and the oil industry is the major contributor to its economy. A large number of oil fields and related installations in Assam are located in forest areas or on their fringes where malaria is a serious problem among field staff and security personnel, adversely affecting oil production. We carried out an operational research study for one year in a forest-based industrial security camp of Dibrugarh district and developed an effective malaria control strategy for such areas., Methods: The specific strategy was formulated and implemented after taking into account the local epidemiology of malaria, vector's ecology and malaria risk behaviour of the camp inmates. The strategy was based on reducing the man-vector contact, using deltamethrin-treated mosquito nets in conjunction with mosquito repellent cream and weekly chemoprophylaxis with 300 mg chloroquine. The impact of the strategy was monitored entomologically and epidemiologically for one year after implementation., Results: The mean landing rate of Anopheles dirus, the vector mosquito in the camp area, was 5.03 per person per night during the monitoring. In spite of such a high density of the vector, the man-vector contact was effectively checked by the intervention measures adopted. As a result, the incidence of malaria in the camp was reduced by > 90% as compared to previous years and the number of malaria cases came down from 6.7 per 1000 man-nights in 1998-99 to 0.06 in 2000-01. Mortality due to malaria was completely eliminated., Conclusion: Control of malaria should be based on the local determinants of transmission. The use of insecticide-treated mosquito nets in conjunction with a mosquito repellent cream is a good intervention for controlling Anopheles dirus-transmitted malaria in the forests of north-east India. The control module developed on the principle of reducing man-mosquito contact is easy to implement, cost-effective and replicable in similar forest-based locations.

Two hundred and sixty seven patients of uncomplicated P. falciparum malaria completed study in a multicentric phase III clinical trial of Arteether. Arteether was given intramuscularly in a dose of 150 mg daily for three consecutive days. Each patient was followed upto 28 days of alpha, beta arteether therapy. The cure rate was 97% with fever clearance time between 1-7 days (24-168 hours) and parasite clearance time between 1-3 days (24-72 hours). Parasite reappearance rate was found to be 3% and reported at only three of the centres. Following the treatment no adverse effect was observed on haematological, biochemical and vital clinical parameters.

Background: The forested hilly and foothill regions of north-east India are highly endemic for malaria and have a distinct epidemiological pattern. Nearly half the reported cases of malaria are from these areas. A knowledge of the risk factors in this eco-geographic entity may be helpful in formulating a specific control strategy. Hence, we conducted a community-based epidemiological study in a hilly, forested terrain of Arunachal Pradesh and examined different socio-demographic factors to identify those predisposing to the occurrence of malaria, especially Plasmodium falciparum infection, in such areas., Methods: Four epidemiological surveys were carried out during 1997 in 7 villages located at the fringes of a forest (total population: 1177) under Nompong Primary Health Centre of Changlang district, Arunachal Pradesh. Blood slides were collected randomly from the inhabitants, irrespective of their fever status, ensuring at least 50% coverage. One hundred and thirty-four microscopically confirmed Plasmodium falciparum cases were identified and 536 controls were randomly selected from the list of uninfected inhabitants. Relevant socio-demographic information was obtained from both cases and controls. The data were analysed by simple and multiple logistic regression using the unconditional maximum likelihood method., Results: Factors which were found to be strongly associated with Plasmodium falciparum malaria on univariate analysis were age, ethnicity, village of residence and accessibility to the nearest health care facility. However, in multiple regression analysis, after controlling for the effects of confounding variables, the only risk factor identified was accessibility to the nearest health care facility (adjusted odds ratio: 4.5; 95% CI: 1.8-11.3; p < 0.0001 for those at a distance of 2-8 km and adjusted odds ratio: 11.1; 95% CI: 4.1-30.0; p < 0.0001 for those > 8 km away)., Conclusion: Distance, particularly non-motorable distance, from the place of residence to the nearest health care facility was a major risk factor for malaria in this hilly forested terrain. This indicates the need for special efforts to detect cases early and institute treatment promptly in such areas of the north-eastern region, so as to reduce the morbidity and mortality of malaria.

An investigation of a malaria epidemic was carried out in Tamulpur Primary Health Centre, district Nalbari, Assam during April 1995. The analysis revealed that children between 3 and 12 years of age who were treated and who recovered clinically from fever during the epidemic were instrumental in the progression of the epidemic by acting as Plasmodium falciparum gametocyte reservoirs. Special efforts are required for treatment of children below 12 years during an epidemic.

Thirty patients of uncomplicated Plasmodium falciparum malaria completed a clinical trial of arteether alpha/beta conducted in a malaria endemic tea garden of district Dibrugarh, Assam. Arteether was given intramuscularly in once a day dose of 150 mg for three consecutive days. The cure rate was 100 per cent with mean fever and parasite clearance time of 42.4 +/- 17.5 and 37.6 +/- 13.6 h respectively. Recrudescence/reinfection rate was 6.7 per cent. Palpable spleens of twenty out of twenty one cases on day 0 became non palpable within 28 days. Following the treatment, percentage of hemoglobin improved marginally with no remarkable change in total and differential leucocyte count. Arteether alpha/beta, besides being a potent and fast acting schizontocidal drug, also exhibited gametocytocidal action on P. falciparum.