Prevalence and force of Plasmodium vivax blood-stage infection and associated clinical malaria burden in the Brazilian Amazon

BACKGROUND Understanding the epidemiology of malaria through the molecular force of the blood-stage infection of Plasmodium vivax (molFOB) may provide a detailed assessment of malaria transmission. OBJECTIVES In this study, we investigated risk factors and spatial-temporal patterns of incidence of Plasmodium infection and clinical malaria episodes in three peri-urban communities of Manaus, Western Brazilian Amazon. METHODS Monthly samples were collected in a cohort of 1,274 individuals between April 2013 and March 2014. DNA samples were subject to Plasmodium species. molFOB was calculated by counting the number of genotypes observed on each visit, which had not been present in the preceding two visits and adjusting these counts by the respective times-at-risk. FINDINGS Respectively, 77.8% and 97.2% of the population remained free of P. vivax and P. falciparum infection. Expected heterozygosity for P. vivax was 0.69 for MSP1_F3 and 0.86 for MS2. Multiplicity of infection in P. vivax was close to the value of 1. The season was associated with P. vivax positivity [adjusted hazard ratio (aHR) 2.6 (1.9-5.7)] and clinical disease [aHR 10.6 (2.4-47.2)]. P. falciparum infection was associated with previous malarial episodes [HR 9.7 (4.5-20.9)]. Subjects who reported possession of a bed net [incidence rate ratio (IRR) 1.6 (1.2-2.2)] or previous malaria episodes [IRR 3.0 (2.0-4.5)] were found to have significantly higher P. vivax molFOB. MAIN CONCLUSIONS Overall, P. vivax infection prevailed in the area and infections were mostly observed as monoclonal. Previous malaria episodes were associated with significantly higher P. vivax molFOB.

Prevalence of P. falciparum Gametocyte Carrying between Two Sympatric Ethnic Groups Living in Seasonal Malaria Transmission Setting of Burkina Faso after Universal Bed Nets Coverage Campaigns

Aims: This study aimed to compare the prevalence of P. falciparumgametocyte carriage in two sympatric ethnic groups living in seasonal malaria transmission setting in Burkina Faso.Study Design: A cross-sectional survey was conducted from September to November 2017 in children aged from 2 to 12 years and living in Barkoundouba, avillage located at the Northeast part of Ouagadougou, capital city of Burkina Faso. The study participants were subject to clinical examination including axillary temperature. Blood samples were collected from finger pricks to performed RDT and blood smears for malaria diagnosis and on filter paper for molecular detection of the parasite. Any case of fever (temperature ≥ 37.5°C) with RDT positive was treated according to national guideline.Methodology:We included 461 patients in this study. P. falciparumpresence and densities were determined by microscopy using Giemsa-stained thick blood smears. The nested PCR was used toconfirm the presence of the asexual parasites assessed by the microscopy. Results: P. falciparumprevalence assessed by microscopy was 83 (32.55%) and 103 (50%) for Fulani and Mossirespectively,whereas the prevalence by nested PCR was 88 (39.11%) for Fulani and 121 (68.75%) for Mossi. The gametocyte carriage in the two ethnic groups was: 3.53% for Fulani and 11.65% for Mossi. The prevalence ratio for P. falciparumasymptomatic and gametocyte carriers was 1.5 and 3 in favor of Mossi group respectively.Conclusion:This study showed that the Fulani have a lower prevalence of P. falciparumcompared to the Mossi group despite the decrease of parasitemia and prevalence in both groups compared to previous studies

Malaria transmission in Tripura: disease distribution & determinants.

Background & objectives: Malaria is a major public health problem in Tripura and focal disease outbreaks are of frequent occurrence. The State is co-endemic for both Plasmodium falciparum and P. vivax and transmission is perennial and persistent. The present study was aimed to review data on disease distribution to prioritize high-risk districts, and to study seasonal prevalence of disease vectors and their bionomical characteristics to help formulate vector species-specific interventions for malaria control. Methods: Data on malaria morbidity in the State were reviewed retrospectively (2008-2012) for understanding disease distribution and transmission dynamics. Cross-sectional mass blood surveys were conducted in malaria endemic villages of South Tripura district to ascertain the prevalence of malaria and proportions of parasite species. Mosquito collections were made in human dwellings of malaria endemic villages aiming at vector incrimination and to study relative abundance, resting and feeding preferences, and their present susceptibility status to DDT. Results: The study showed that malaria was widely prevalent and P. falciparum was the predominant infection (>90%), the remaining were P. vivax cases. The disease distribution, however, was uneven with large concentration of cases in districts of South Tripura and Dhalai coinciding with vast forest cover and tribal populations. Both Anopheles minimus s.s. and An. baimaii were recorded to be prevalent and observed to be highly anthropophagic and susceptible to DDT. Of these, An. minimus was incriminated (sporozoite infection rate 4.92%), and its bionomical characteristics revealed this species to be largely indoor resting and endophagic. Interpretation & conclusions: For effective control of malaria in the State, it is recommended that diseases surveillance should be robust, and vector control interventions including DDT spray coverage, mass distribution of insecticide-treated nets/ long-lasting insecticidal nets should be intensified prioritizing population groups most at risk to avert impending disease outbreaks and spread of drug-resistant malaria.

Monitoring the durability of long-lasting insecticidal nets in field conditions in Nepal.

Understanding and improving the durability of long-lasting insecticidal nets (LLINs) in the field is critical for the success of malaria prevention using mosquito nets, as well as contributing to procurement decisions based on the number of years of protection, rather than the current practice of unit cost. Using the recently published guidelines from the World Health Organization (WHO) some progress has been made in the monitoring and assessment of performance of nets in the field. This paper describes the protocol of an ongoing retrospective study of the attrition rate, physical integrity and bioefficacy of three polyester LLIN products that were distributed during 2010 to 2013 in Nepal. It is hoped that robust and auditable data on net survival (physical integrity and bioefficacy) of these three brands in different environments will assist the Nepal National Malaria Control Programme in planning future LLIN-replacement strategies, including behaviourchange communication about LLIN care and maintenance. The advantages and disadvantages of prospective and retrospective cross-sectional approaches are discussed, including appropriate strategies to validate the timing for mass distribution of nets. Similar studies should be done in other countries to (i) track LLIN durability to support management of resupply, and (ii) inform procurement decisions at the global level. New, more predictive, textile laboratory testing is also urgently needed.

Safety of polyethylene glycol recombinant human granulocyte colony-stimulating factor in treating non-small cell lung cancer patients at I b stage

OBJECTIVE@#To investigate resistance and safety of HHPG-19K in treating non-small cell lung cancer patients.@*METHODS@#A total of 30 cases were selected and randomly divided into 5 groups: three HHPG-19K groups of different dosage (60 μg/kg/day, 100 μg/kg/day, 200 μg/kg/day), positive control group (Filgrastim, namely G-CSF5 μg/kg/day) and negative control group. Safety indexes of 5 groups were observed and compared.@*RESULTS@#All patients had adverse event (100%) in three HHPG-19K groups, and increased ALP, ALT and AST were main events. The degree was mild to moderate. There was no significant difference in the incidence of adverse event between dosage groups and positive control group no difference. But the incidence of negative control group was 13%, which was significantly lower than dosage groups and positive control group.@*CONCLUSIONS@#non-small cell lung cancer patients have satisfactory tolerance to HHPG-19K, and have no resistance. Besides, dosage at 100 μ g/kg is the most safe.

Impact of dams and irrigation schemes in Anopheline (Diptera: Culicidae) bionomics and malaria epidemiology / Impacto de hidrelétricas e campos de irrigação na bionomia dos anofelinos (Diptera:Culicidae) e na epidemiologia da malária

Irrigation schemes and dams have posed a great concern on public health systems of several countries, mainly in the tropics. The focus of the present review is to elucidate the different ways how these human interventions may have an effect on population dynamics of anopheline mosquitoes and hence, how local malaria transmission patterns may be changed. We discuss different studies within the three main tropical and sub-tropical regions (namely Africa, Asia and the Pacific and the Americas). Factors such as pre-human impact malaria epidemiological patterns, control measures, demographic movements, human behaviour and local Anopheles bionomics would determine if the implementation of an irrigation scheme or a dam will have negative effects on human health. Some examples of successful implementation of control measures in such settings are presented. The use of Geographic Information System as a powerful tool to assist on the study and control of malaria in these scenarios is also highlighted.

Intervenções humanas como projetos de irrigação e usinas hidrelétricas, tem se transformado em graves problemas de saúde em muitos países, especialmente naqueles localizados nos trópicos. No presente artigo discutimos os efeitos que essas intervenções causam a dinâmica populacional dos anofelinos e nos padrões de transmissão de malaria. Foram revisados estudos feitos nas três principais regiões geográficas dos trópicos e sub-trópicos (África, Ásia e o Pacífico e Américas). Constatamos que os padrões da transmissão da malária antes da introdução dos empreendimentos, as medidas de controle, os movimentos demográficos, os padrões comportamentais das comunidades humanas e a bionomia dos anofelinos locais determinarão se o estabelecimento de campos de irrigação e/ou usinas hidrelétricas podem influenciar negativamente na saúde das pessoas. São apresentados exemplos de medidas de controle bem sucedidas nesses cenários. A utilização de Sistemas de Informação Geográfico tem sido destacada como uma importante ferramenta para subsidiar o estudo e controle da malária em áreas sob impacto ambiental.

Appropriate Time for Primaquine Treatment to Reduce Plasmodium falciparum Transmission in Hypoendemic Areas

Artemesinin-combination therapies (ACT) for falciparum malaria reduce gametocyte carriage, and therefore reduce transmission. Artemisinin derivatives will act against only young gametocytes whereas primaquine acts on mature gametocytes which are present usually in the circulation at the time when the patient presents for treatment. Both artemisinin derivatives and primaquine have short half-lives, less than 1 hr and 7 hr, respectively. Therefore, asexual parasites or young gametocytes remain after completed ACT. A single dose of primaquine (0.50-0.75 mg base/kg) at the end of ACT can kill only mature gametocytes but cannot kill young gametocytes (if present). Remaining asexual forms after completion of ACT course, e.g., artesunate-mefloquine for 3 days, may develop to mature gametocytes 7-15 days later. Thus, an additional dose of primaquine (0.50-0.75 mg base/kg) given 2 weeks after ACT completion may be beneficial for killing remaining mature gametocytes and contribute to more interruption of Plasmodium falciparum transmission than giving only 1 single dose of primaquine just after completing ACT.

Entomological assessment of the potential for malaria transmission in Kibera slum of Nairobi, Kenya.

Background & objectives: Malaria in urban and highland areas is emerging as a significant public health threat in Kenya which has seen a dramatic increase in malaria transmission in low risk highland areas. The objectives of the study were to find and incriminate potential vectors of malaria in Kibera, Nairobi. Methods: One hundred and twenty houses within Lindi area of the southern central section of Kibera slum in Nairobi were chosen randomly and global positioning system (GPS) mapped. Day resting indoor mosquitoes were collected from January 2001 to December 2003. Larvae were collected between 2002 and 2004 and reared in the insectary to adults. Results: A total of 176,993 mosquitoes were collected. Out of this, 176,910 were Culex fatigans and 83 were Anopheles gambiae s.l. Mosquito population peaked during the long rains in April to May and the short rains in November and December. Blood meal analysis of An. gambiae s.l. female mosquitoes revealed 0.97 human blood index. No mosquito was found positive for Plasmodium falciparum sporozoites. Anopheles gambiae s.l. mosquitoes were found breeding in polluted water and 95% of the larvae were identified as An. arabiensis. Interpretation & conclusion: Anopheles gambiae s.l., malaria vector is present in Nairobi and it breeds in polluted water. Anopheles arabiensis is predominantly preferring humans as blood meal source, thus, showing ecological flexibility within the species.

Impact of etofenprox (Vectron® 20 WP) indoor residual spray on malaria transmission.

Background & objectives: A longitudinal study was carried out to assess the impact of indoor residual spray with Vectron® 20 WP (etofenprox) against Anopheles culicifacies and on malaria transmission in a selected village of Dadri primary health centre (PHC), District Gautam Budh Nagar, Uttar Pradesh, India. Methods: Two villages, namely Patadi and Anandpur in District Gautam Budh Nagar, Uttar Pradesh, with similar malaria incidence and vector prevalence were selected for the present evaluation. In one village two rounds of indoor spraying of etofenprox (0.1 g/m2) were done at an interval of 12 wk and the other village was kept as control where no intervention except intensive active surveillance for early detection and prompt treatment (EDPT) was undertaken during the study period. Entomological and epidemiological data were collected using standard procedures. Results: Persistence of the effectiveness of etofenprox against An. culicifacies was observed up to 12 wk. Spraying of etofenprox signifi cantly reduced the density signififi (P<0.001) and proportion of parous An. culicifacies mosquitoes (P<0.05) in the experimental village. There was a signififi cant reduction in malaria cases in the experimental village during the post-spray period when compared to the control village (P<0.05). No adverse effect was reported by the spraymen and inhabitants during and after the spray. Interpretation & conclusion: Indoor residual spray of etofenprox (0.1 g/m2) with an interval of three months in between two rounds of spray produced the desired impact in reducing the indoor resting density of vector mosquitoes and also in curtailing malaria transmission in the sprayed village when compared with the control village without spray.

Anopheles darlingi bionomics and transmission of Plasmodium falciparum, Plasmodium vivax and Plasmodium malariae in Amerindian villages of the Upper-Maroni Amazonian forest, French Guiana

French Guiana is one of the areas in South America most affected by malaria and where the disease has become a serious public health problem. In spite of this situation, little recent entomological data are available from the main localities where the disease occurs, even though they are crucial for development of an effective vector control strategy. A longitudinal entomological survey was carried out from March 2000-February 2002 in three Amerindian villages, namely Twenké, Taluène and Cayodé, located in the Amazonian forest of the Upper-Maroni area, to assess anopheline mosquitoes and malaria transmission dynamics. Anopheles darlingi (Diptera: Culicidae) was the most abundant mosquito species caught during the study. This efficient American malaria vector was active the entire year, but showed an evident peak of abundance during the main rainfall season, from April-June, with an average human biting rate of 255.5 bites per person per night. Parity rates were homogeneous all year, indicating no significant seasonal variability in female survival rates. Estimated vectorial capacity indices were higher during the rainy season, even though the risk of transmission was present throughout the year (VCI > 1). A total of 14 An. darlingi were found infected with Plasmodium falciparum, Plasmodium vivax or Plasmodium malariae. The annual circumsporozoite indices were 0.15, 0.14 and 0.05, and the entomological inoculation rates were 22.8, 27.4 and 14.4 infected bites per person per year in Twenké, Taluène and Cayodé, respectively. An. darlingiwas endo-exophagic and rather exophilic in these localities. The species was collected throughout the night but was more aggressive between 21:30-03:30 h and after 05:30 h. Parity rates were homogeneous during the entire night. Impregnated hammock and/or bed nets, coupled with the use of mosquito repellents, as well as the early treatment of malarial cases, appear to be the most suitable tools for fighting...

Risk of Malaria Transmission by Blood Donation from Army Soldiers in Korea / 감염

BACKGROUND: Screening of donor blood for malaria has not been activated in Korea yet in spite of the recent resurgence of tertian malaria among Korean army soldiers in Delimited Militarized Zone areas. Prospective donors (travelers, immigrants, refugees, citizens or residents) following a visit to or coming from an endemic area who have had malaria or taken antimalarial prophylaxis should be deferred for 3 years after cessation of therapy or after departure from malarial area. We studied the risk of the transmission of malaria, especially through army blood donation which comprised up to 57.8% of whole blood donation in Korea. METHODS: The data were collected by personal interview and review of donation records of Korea Red Cross Center and medical records from 174 army soldiers with malaria who admitted to Army Hospital from May 1995 to October 1996. We analyzed the time interval between onset of illness and blood donation, and geographic distribution of the patients. RESULTS: About 70.7% (123/174) of the patients donated blood before the onset of illness, and the interval between blood donation and onset of illness ranged from 2 days to 2,750 days (mean 377, standard deviation 488). Patients who donated blood within 3 years before onset of illness were 87.8%(n=108) of the total blood donation. All donation (n=18) after treatment were within 3 years from 46 days to 342 days (mean 138, standard deviation 80.7). The frequent of blood donations were from the prevalent areas of malaria such as Pajoo City (40%), Younchon Kun (29%), Cholwon Kun (15.5%) and others(15.5%). CONCLUSION: We showed that donated army blood a risk of malaria transmission. Therefore the blood bank needs to set strict guidelines for blood donation especially from Korean army soldiers to control malaria transmission.

STUDIES ON DISTRIBUTION AND BEHAVIOR OF ANOPHELES MINIMUS AND ITS ROLE OF MALARIA TRANSMISSION IN HAINAN PROVINCE AT PRESENT / 中国寄生虫学与寄生虫病杂志

Anopheles minimus was once a main malaria vector in Hainan Island and had been e-liminated basically through the campaign of indoor residual spraying launched in 1959. It again became an incriminated vector of some focal malaria outbreaks in recent years. The present study was conducted in a selected county-Danxian and a typical hilly area-Feibar in the west part of Danxian county in 1989-1990.An. minimus was found in 50% and 62. 5 % of the surveyed sites at mountainous and hilly area of Danxian county,but not found in coastal region. An. minimus was found in all 18 sites surveyed in Feibar district constituting 52% of anopheline composition. Man-biting rate made by human-baited collection was 3. 2 before midniaght and 38. 2 when collected through whole night in some sites. However, the behaviour characteristics of An. minimus has changed. It has become exophilic,exophagic, and has an equal preference for man and cattle. The vectorial capacity of An. minimus estimated by quantitative data was in accord with malaria infection rate in Feibar district ,and the malaria infection rate among the inhabitants in three types of residential quarter with different socioeconomic conditions. Malaria infection rates of residential quarter of land-reclamation outcomers, villagers and state farm residents were 10%,2. 9% and 0. 5% respectively during 40 days from July to August,1990.Owing to the fact that An. minimus has become a secondary vector only next to An. dirus, with a wide range of distribution and a considerable different characteristics in behaviour compared to that before spraying campaign , it is suggested that a malaria control programme must be seriously planned to adjust the new problem of malaria epidemiology in Hainan Province.

GIS/RS/GPS Application in the Study of Relationship between Natural Factors and Malaria Transmission / 中国寄生虫学与寄生虫病杂志

Malaria transmission is highly related to the natural factors such as temperature, rainfall and topography.Recently, the GIS/RS/GPS techniques were developed based on computer science and spatial analysis technology, which were widely used in data collection and analysis, establishment of mathematics model.This paper reviews the applications and development of GIS/RS/GPS techniques in the studies of relationship between natural factors and malaria transmission.