Factors associated with community engagement in areas with high and low incidence of local malaria cases in Zanzibar

Introduction: the prevalence of asymptomatic infection in the general population in Zanzibar has declined from above 25% in 2005 to less than 1% in 2010. Despite these achievements, in 2021, the number of malaria cases increased by two folds. This study aimed at understanding the levels of community engagement towards malaria elimination and factors associated with them to provide recommendations that can be used to reinforce community engagement. Methods: a descriptive cross-sectional survey was conducted using structured questionnaires to 431 randomly selected households. The interviewees were the heads of households or representative adults above 18 years. Univariate and multivariate analysis was done to determine the association between social demographic characteristics, malaria knowledge, practicing malaria prevention interventions and status of community engagement. Statistical significance test was declared at P- value <0.05. Results: of all respondents, 261 (60.6%) were not engaged in either planning or implementation of malaria interventions, of which 120 (45.9%) participants were in the high malaria transmission and 141 (54.0%) from the low malaria transmission (P=0.018). Factors significantly associated with increased odds of community engagement were the level of knowledge on malaria (P= 0.002) and factors independently associated with reduced odds of community engagement was the level of malaria burden (P= 0.01). Conclusion: level of malaria knowledge and malaria burden were associated with community engagement. There is a need to increase malaria knowledge in the community based on the existing gaps as this study suggests that having high malaria knowledge can significantly contribute to increased opportunity for community engagement.

Time trends and changes in the distribution of malaria cases in the Brazilian Amazon Region, 2004-2013

Recent efforts to reduce malaria incidence have had some successes. Nevertheless, malaria persists as a significant public health problem in the Brazilian Amazon. The objective of this study was to describe changes in malaria case characteristics and to identify trends in malaria incidence in the Brazilian Amazon. This study used data from the Malaria Epidemiological Surveillance and Case Notification Information System from 2004 to 2013. The annual parasite incidence (API) was calculated and joinpoint regression was used to assess the trends in API over time. There was a sharp increase in API in the state of Acre, followed by two periods of decrease. Pará also presented inconsistent decreases over the study period. Amapá, Amazonas, Rondônia, and Roraima showed statistically significant decreases over the period. The sharpest decrease occurred in Rondônia, with a reduction of 21.7% in the average annual percent change (AAPC) (AAPC: -21.7%; 95% confidence interval: -25.4%, -17.8%; p < 0.05). This panorama of malaria incidence highlights the importance of integrating evidence-based malaria surveillance and control. Malaria is highly preventable, and eliminating its transmission should be a goal in coming decades.

Trend in Malaria Incidence Rates (2006-2013) in Edo State, Nigeria.

Background: Detailed information on the severity of malaria and other diseases across operational areas is a prerequisite to the judicious utilization of limited effective tools for the control in Africa. Methods: Records of Patients, from the 18 Local Government Areas (LGAs), who visited Health Centres across Edo State, 2006-2013, and stored in the Ministry of Health database in Benin City were analysed. Patients were placed in 3 groups (out-patients, In-patients, Pregnant Women). Human population data, in the 18 LGAs over the period were obtained from the National Population Commission. Malaria incidence rates were estimated. The proportions of patients in the 3 categories annually across LGAs were determined. Results: Malaria Incidence rates increased 2-13 folds over the period in all LGAs, except in Esan West where there was a significant reduction in 2011. The highest rates were recorded at Esan Central (13.66%) and Uhunmwonde (11.50%). The highest increases in the proportions of patients with severe malaria were at Uhunmwonde, Igueben and Orhionmwon LGAs. In contrast, reductions in the proportions of severe malaria were in Esan Northeast and Owan West. The highest increases in the proportions of pregnant women patients were in Esan central and Esan West; in contrast, major reductions were observed at Oredo and Igueben. Conclusion: The multi-faceted Federal and State Governments Intervention Policies and Strategies have apparently not been effective in the State. There is an urgent need for the intensification of efforts, including increase in the number of ITNs and upgrading of facilities at the Primary Health Care Centres for holistic diagnosis.

Impact of changing over of insecticide from synthetic pyrethroids to DDT for indoor residual spray in a malaria endemic area of Orissa, India.

Background & objectives: Development of insecticide resistance in malaria vectors has been a major problem for achieving effective vector control. Due to limited availability of insecticides, the only option is management of resistance by judiciously using the insecticides and rotating them to maintain their effectiveness. This study was carried out in a malaria endemic area of Sundergarh district in Orissa where synthetic pyrethroids (SP) were in use for the last couple of years. The change-over from SP to DDT was done in one arm of study, and the other two arms remained on SP and insecticide-treated nets (ITN). Entomological and parasitological monitoring was done to assess the impact. Methods: The study design comprised of three arms (i) two rounds of indoor residual spraying (IRS) with DDT 1g/m2 as a change-over insecticide in areas previously under synthetic pyrethroids; (ii) two rounds of IRS with synthetic pyrethroid (alphacypermethrin, ACM) @ 25 mg/m2; and (iii) an unsprayed area under ITN/long lasting insecticide nets (LNs). Indoor residual spraying was undertaken under strict supervision to maintain quality and coverage. Contact bioassays were conducted to know the persistence of insecticide on sprayed surfaces and adult vector density was monitored in fixed and randomly selected houses. Malaria incidence was measured through fortnightly domiciliary surveillance under primary health care system in all the study villages. Results: The insecticide susceptibility tests showed that An.culicifacies was resistant to DDT but susceptible to malathion and ACM. However, An. fluviatilis was susceptible to all the three insecticides. ACM was effective in killing An. culicifacies on mud and wooden sprayed surfaces and maintained effective bioefficacy ranging from 92 to 100 per cent up to five months, whereas DDT failed to achieve effective mortality in An.culicifacies. However, there was significant decline in the density of An.culicifacies in ACM and DDT areas in comparison to ITNs/LNs. There was 61 per cent reduction in the slide positivity rate in ACM area in comparison to 48 and 51 per cent in DDT and ITN/LNs areas, respectively. The adjusted incidence rate of malaria cases per 1000 population in three study areas also showed significant declines within each group. Interpretation & conclusions: The present findings show that the change-over of insecticide from synthetic pyrethroids to DDT brings about the same epidemiological impact as envisaged from continuing SP spray or distributing insecticide treated nets/long-lasting insecticidal nets provided there is a good quality spray and house coverage.

A ocorrência de malária em quatro municípios do estado do Pará, de 1988 a 2005, e sua relação com o desmatamento / Occurrence of malaria in four cities in the state of Pará during 1988 to 2005 and its relationships with deforestation

O objetivo deste trabalho foi estudar a ocorrência de malária em quatro diferentes regiões representativas do estado do Pará, buscando suas possíveis relações com as taxas de desmatamento. Foi realizado um estudo retrospectivo, com dados secundários, no período de 1988 a 2005, através de casos de malária registrados em quatro municípios do Estado (Anajás, Itaituba, Santana do Araguaia e Viseu), como também das taxas de desmatamento fornecidas pelo PRODES-INPE. Aplicou-se a técnica dos Quantis para se estabelecer cinco categorias ou classes de incidência da malária para cada município, sendo gerado posteriormente um IPA representativo para o Estado. De 1988 até 1994, as curvas de incidência de malária acompanham os números de desmatamento. A partir de 1995, evidenciaram-se anos consecutivos com altos índices de ocorrência da doença logo após os períodos de altas taxas de desmatamento, como registrado nos anos de 1995, 2000 e 2004. Percebeu-se que após a época de intenso desmatamento, os casos de malária variaram entre alto e muito alto no seu padrão de incidência, apontando que o desmatamento pode ser um fator de incremento na frequência e aumento no número de pessoas infectadas no estado do Pará.

The purpose of this paper is to study occurrence of malaria in four different regions of the state of Pará and its possible relationships with deforestation rates. A retrospective study using secondary data from 1988 to 2005, using malaria incidence records reported in four cities in the state (Anajás, Itaituba, Santana do Araguaia and Viseu), as well as deforestation rates provided by the PRODES-INPE. The quantiles method was applied to establish five categories or classes of malaria incidence for each city, and a state IPA was generated with the contributions of these cities. From 1988 to 1994, the curves of incidence of malaria follow deforestation rates. From 1995, there are consecutive years of high incidence levels after years of high deforestation rates, as registered in 1995, 2000 and 2004. It was noticed that after periods of intense deforestation the occurrence of malaria presented an incidence pattern between high and very high, suggesting that deforestation may be a factor in maintaining and increasing the number of cases in the state of Pará.

Field evaluation of ZeroFly® - an insecticide incorporated plastic sheeting against malaria vectors & its impact on malaria transmission in tribal area of northern Orissa.

Background & objectives: Insecticide incorporated plastic sheeting is a new technology to control mosquitoes in emergency shelter places and also temporary habitations in different locations. Therefore, field studies were conducted to assess the efficacy of ZeroFly® plastic sheeting treated with deltamethrin on prevailing disease vectors Anopheles culicifacies and An. fluviatilis and its impact on malaria transmission in one of the highly endemic areas of Orissa. Methods: The study was conducted in Birkera block of Sundargarh district, Orissa state. The study area comprised 3 villages, which were randomized as ZeroFly plastic sheet, untreated plastic sheet and no sheet area. ZeroFly plastic sheets and untreated plastic sheets were fixed in study and control villages respectively covering all the rooms in each household. Longitudinal studies were conducted on the bioefficacy with the help of cone bioassays, monitoring of the mosquito density through hand catch, floor sheet and exit trap collections and fortnightly domiciliary active surveillance in all the study villages. Results: In ZeroFly plastic sheeting area, there was a significant reduction of 84.7 per cent in the entry rate of total mosquitoes in comparison to pre-intervention phase. There was 56.2 per cent immediate mortality in total mosquitoes in houses with ZeroFly sheeting. The overall feeding success rate of mosquitoes in the trial village was only 12.5 per cent in comparison to 49.7 and 51.1 per cent in villages with untreated plastic sheet and no sheet respectively. There was a significant reduction of 65.0 and 70.5 per cent in malaria incidence in ZeroFly plastic sheeting area as compared to untreated plastic sheet and no sheet area respectively. Interpretation & conclusions: Our study showed that introduction of ZeroFly plastic sheets in a community-based intervention programme is operationally feasible to contain malaria especially in the high transmission difficult areas.

Vector bionomics and malaria transmission in the Upper Orinoco River, Southern Venezuela

A longitudinal epidemiological and entomological study was carried out in Ocamo, Upper Orinoco River, between January 1994 and February 1995 to understand the dynamics of malaria transmission in this area. Malaria transmission occurs throughout the year with a peak in June at the beginning of the rainy season. The Annual Parasite Index was 1,279 per 1,000 populations at risk. Plasmodium falciparum infections accounted for 64 percent of all infections, P. vivax for 28 percent, and P. malariae for 4 percent. Mixed P. falciparum/P. vivax infections were diagnosed in 15 people representing 4 percent of total cases. Children under 10 years accounted for 58 percent of the cases; the risk for malaria in this age group was 77 percent higher than for those in the greater than 50 years age group. Anopheles darlingi was the predominant anopheline species landing on humans indoors with a biting peak between midnight and dawn. A significant positive correlation was found between malaria monthly incidence and mean number of An. darlingi caught. There was not a significant relationship between mean number of An. darlingi and rainfall or between incidence and rainfall. A total of 7295 anophelines were assayed by ELISA for detection of Plasmodium circumsporozoite (CS) protein. Only An. darlingi (55) was positive for CS proteins of P. falciparum (0.42 percent), P. malariae (0.25 percent), and P. vivax-247 (0.1 percent). The overall estimated entomological inoculation rate was 129 positive bites/person/year. The present study was the first longitudinal entomological and epidemiological study conducted in this area and set up the basic ground for subsequent intervention with insecticide-treated nets.

THE COURSE OF MALARIA CONTROL AND PRESENT STATUS IN ZHEJIANG PROVINCE / 中国寄生虫学与寄生虫病杂志

Through forty years' sustained efforts in the prevention and treatment of malaria in Zhejiang Province, the malaria incidence dropped from 76. 65k in the Fifties to 0. 91 in the Eighties. Three malaria epidemics emerged in 1954 ,1962 and 1973, respectively, among them the epidemic in 1962 was the most serious one with 0. 88 million cases reported and an incidence of 330. The annual incidence of the overall counties/cities was below 1 after 1988. Only 172 malaria cases were found in 1992, the incidence being 0. 04. No indigenous malaria case was found in 38 counties in 1992, accounting to 43. 7% of the total malaria endemic counties. The number of imported malara cases was 3 829, amounting to 89. 2 % of the total number of cases. Through the spot-check of the Ministry of Public Health in 1993, it was confirmed that the criteria of basic elimination of malaria in the province was attained.