Indigenous Malaria Transmission Research Articles

From eradication to reemergence: the growing threat of malaria in Turkey.

According to WHO, between 2000 and 2021, there were approximately 247 million malaria cases and 627,000 deaths globally, with the majority of cases occurring in sub-Saharan Africa. In Turkey, indigenous P. vivax malaria was a major public health problem until its eradication was achieved in 2010. Although indigenous malaria transmission has been significantly reduced since 2010, the country is challenged with imported malaria due to increasing global travel and migration from endemic regions. In this study, all imported malaria cases admitted to Dr. Sadi Konuk Research and Training Hospital, Istanbul, between 2018 and 2023 were included. DNA extraction was performed using archived slides and EDTA blood samples. Real-time PCR was performed to identify samples at the species level using previously reported primers and probes. In addition, all available patient demographics are presented. During the six years between 2018 and 2023, 157 patients were diagnosed with imported malaria. According to the real-time PCR results, 149 cases were P. falciparum (94.9%), five cases were P. vivax (3.2%), two cases were P. ovale (1.3%), and one case was P. malariae (0.6%). The male/female ratio among diagnosed patients was 2.34 (110♂/47♀) among diagnosed patients. Plasmodium falciparum was detected in patients from all African regions, whereas P. vivax was detected only in patients from Liberia and Djibouti. Although malaria cases in Turkey have significantly decreased due to elimination efforts and effective public health interventions, the recent increase in both imported and indigenous cases, as well as the presence of suitable vector species in the country, indicates that malaria still remains a serious public health problem for Turkey.

Linkages between malaria and malnutrition in co-endemic regions of India

IntroductionMalaria and malnutrition are key public health challenges in India. However, the relationship between them is poorly understood. Here, we aimed to elucidate the potential interactions between the two health...

Knowledge, attitudes, and practices regarding malaria control among the slash and burn cultivators in Rangamati Hill tracts of Bangladesh

BackgroundSlash and burn cultivators are a significant risk group for malaria in South-East Asia. As envisaged in the National Strategic Plan for Malaria Elimination, Bangladesh aims to achieve zero indigenous malaria transmission by 2030. For the national plan to move from malaria control to malaria elimination, targeting the population of slash and burn cultivators is of overriding importance.MethodsThe study used an explorative mixed method design to investigate the knowledge, attitudes, and practices (KAP) regarding malaria prevention and treatment in an endemic area of Bangladesh. Adult slash and burn cultivators in two sub-districts of the Rangamati District were selected and interviewed. Four focus group discussions were conducted, and this was followed by a cross-sectional quantitative survey with 200 participants.ResultsThe respondents’ general knowledge about malaria transmission and modes of prevention and treatment was good. However, there were some gaps regarding knowledge about specific aspects of malaria transmission and in particular about the increased risk associated with their occupation. Despite a much-reduced incidence of malaria in the study area, the respondents perceived the disease as life-threatening and knew that it needs rapid attention from a health worker. Moreover, the specific services offered by the local community health workers for malaria diagnosis and treatment were highly appreciated. Finally, the use of insecticide-treated mosquito nets (ITN) was considered as important and this intervention was uniformly stated as the main malaria prevention method.ConclusionsThe findings from this study on promising KAP characteristics in the slash and burn cultivator population are reassuring that the goal of malaria elimination by the year 2030 can be achieved in Bangladesh.

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.

Variation in species composition and infection rates of Anopheles mosquitoes at different altitudinal transects, and the risk of malaria in the highland of Dirashe Woreda, south Ethiopia

BackgroundThe transmission of malaria is heterogeneous, and varies due to altitude. The information on whether the transmission of malaria is indigenous or imported to highland areas is scarce. Therefore, this study aimed to assess the species composition and infection rates of Anopheles at different altitudinal transects, and the risk of malaria if any in the highland of Dirashe Woreda, South Ethiopia.MethodsThis study was conducted in Gato (low altitude; average elevation of 1273 m), Onota (mid-altitude; average elevation of 1707 m) and Layignaw-Arguba (high altitude; average elevation of 2337 m) from August 2015 to April 2016. Anopheles mosquitoes were sampled using Centers for Disease Control and Prevention (CDC) light traps from thirty houses (ten houses from each village). The circum-sporozoite proteins (CSPs) rate and entomological inoculation rate (EIR) of Anopheles mosquitoes were estimated. For the epidemiological survey, malaria cases were collected from laboratory registration books of selected health facilities from (August 2015-April 2016). A cross-sectional survey was done to collect data on malaria vector control activities in each village (August-September 2015).ResultsOne thousand two hundred sixty-eight Anopheles mosquitoes comprising Anopheles arabiensis, An. demeilloni, An. cinereus, An. pharoensis, An. funestus-group, An. pretoriensis, An. christyi, An. ardensis and An. tenebrosus were identified in the study area. Anopheles arabiensis was the dominant species in Gato, whereas An. demeilloni was the dominant species in Layignaw-Arguba. Five mosquitoes, three An. arabiensis from Gato and two An. demeilloni from Layignaw-Arguba, were positive for Plasmodium falciparum CSPs. Plasmodium falciparum CSP rate was 0.4% (95% CI: 0.08–1.15) for An. arabiensis in Gato, and it was 0.64% (95% CI: 0.08–2.3) for An. demeilloni from Layignaw-Arguba. The P. falciparum EIR of An. arabiensis was 8.6 (95% CI: 2.4–33.4) infectious bites/person/nine-months in Gato. Plasmodium falciparum parasite was dominant in Gato (88%) and Onota (57.5%), whereas in Layignaw-Arguba P. vivax (59.4%) occurred most frequently. Increased malaria cases were observed in children age 5–14 years in Gato (P < 0.05), whereas in Onota and Layignaw-Arguba there was no statistically significant difference in malaria cases among the age groups. Households owning at least one long lasting insecticidal net were 92.7% in the study area, and 77.6% slept under the net during the preceding night of the survey. About 64.4% of the households in Gato were protected by the indoor residual spray. However, the spraying was done when the density of local malaria vectors was low.ConclusionIncrimination of Plasmodium CSP positive Anopheles species and the presence of malaria in children under five years in high altitude Layignaw-Arguba may justify the existence of indigenous malaria transmission and the need for effective malaria control. Further investigation and confirmation using more sensitive molecular techniques are however needed to consider An. demeilloni as a proven vector of malaria in Ethiopia.

Strengthening malaria and climate research in Ethiopia

The project “Ethiopian Malaria Prediction System” implemented from 2007 to 2012 combined new population-based malaria transmission information with climate and land use variability data to develop an early warning tool to predict malaria epidemics in Ethiopia. Scientists from Ethiopia and Norway collaborated to incorporate climate variability and forecast information for malaria epidemics. Our study shows that the association between weather and malaria is complex. Statistical models can predict malaria for large areas. However, as malaria transmission varies and depends on local environmental conditions, we need to have good and local knowledge about each area. However, weather variability is the main driver of malaria in Ethiopia. While the generation of precipitation depends on local ascent and cooling of the air, our research provided new data on the transport of moisture into the country that may improve weather forecasting. We developed a new classification of climate zones, have mapped drought episodes in Ethiopia during the last decades, and have improved seasonal weather forecasting. Our hydrology studies show that potential climate change differs among the Ethiopian river basins, with river flows being sensitive to variations in rainfall, and less to temperature changes. The computer model, Open Malaria Warning, incorporates hydrological, meteorological, mosquito-breeding, land-use data, and cattle densities to find out when and where outbreaks are likely to occur. We validated the model with data for malaria transmission in the highlands and lowlands, characterizing malaria transmission over some years in both highlands and lowlands. This provided us with new knowledge on malaria transmission in Ethiopia, how intense the seasonal transmission is, and how malaria occurs in different populations and areas. Our study showed that indigenous malaria transmission during a non-epidemic year takes place above 2000 m altitude. We also showed the ideal temperature for malaria transmission is about 25°C, underlining that global warming may lead to increased risk of malaria in highland areas, and less in the lowlands with already high average temperatures. However, to validate such models, there is a need for several years of active monitoring of malaria cases and mosquito densities. Unfortunately, such data is rare in Africa, and we need to invest in long-term monitoring of malaria transmission.

Operational research to inform a sub-national surveillance intervention for malaria elimination in Solomon Islands

BackgroundSuccessful reduction of malaria transmission to very low levels has made Isabel Province, Solomon Islands, a target for early elimination by 2014. High malaria transmission in neighbouring provinces and the potential for local asymptomatic infections to cause malaria resurgence highlights the need for sub-national tailoring of surveillance interventions. This study contributes to a situational analysis of malaria in Isabel Province to inform an appropriate surveillance intervention.MethodsA mixed method study was carried out in Isabel Province in late 2009 and early 2010. The quantitative component was a population-based prevalence survey of 8,554 people from 129 villages, which were selected using a spatially stratified sampling approach to achieve uniform geographical coverage of populated areas. Diagnosis was initially based on Giemsa-stained blood slides followed by molecular analysis using polymerase chain reaction (PCR). Local perceptions and practices related to management of fever and treatment-seeking that would impact a surveillance intervention were also explored using qualitative research methods.ResultsApproximately 33% (8,554/26,221) of the population of Isabel Province participated in the survey. Only one subject was found to be infected with Plasmodium falciparum (Pf) (96 parasites/μL) using Giemsa-stained blood films, giving a prevalence of 0.01%. PCR analysis detected a further 13 cases, giving an estimated malaria prevalence of 0.51%. There was a wide geographical distribution of infected subjects. None reported having travelled outside Isabel Province in the previous three months suggesting low-level indigenous malaria transmission. The qualitative findings provide warning signs that the current community vigilance approach to surveillance will not be sufficient to achieve elimination. In addition, fever severity is being used by individuals as an indicator for malaria and a trigger for timely treatment-seeking and case reporting. In light of the finding of a low prevalence of parasitaemia, the current surveillance system may not be able to detect and prevent malaria resurgence.ConclusionAn adaption to the malERA surveillance framework is proposed and recommendations made for a tailored provincial-level surveillance intervention, which will be essential to achieve elimination, and to maintain this status while the rest of the country catches up.

Malaria elimination in Isabel Province, Solomon Islands: establishing a surveillance-response system to prevent introduction and reintroduction of malaria

BackgroundThe Solomon Islands National Malaria Programme is currently focused on intensified control and progressive elimination. Recent control efforts in Isabel Province have reduced their malaria incidence to 2.6/1,000 population in 2009 [1] whereas most neighbouring provinces have much higher incidences. A malaria surveillance-response system that involves testing all travellers entering Isabel Province using rapid diagnostic tests (RDT) to prevent cases being imported had been proposed by local health authorities. This study provides information on the feasibility and acceptability of implementing a new approach of surveillance and response in the context of low levels of indigenous malaria transmission in Isabel Province.MethodsA total of 13 focus group discussions (FGD) and 22 key informant interviews (KII) were conducted in Isabel Province, Solomon Islands. Key topics included: the travel patterns of people to, from and within Isabel Province; the acceptability, community perceptions, attitudes and suggestions towards the proposed surveillance programme; and management of suspected malaria cases. This information was triangulated with data obtained from port authorities, airlines and passenger ships travelling to and from Isabel Province in the preceding two years.ResultsTravel within Isabel Province and to and from other provinces is common with marked seasonality. The majority of inter-provincial travel is done on scheduled public transport; namely passenger ships and aircrafts. In Isabel Province there is a healthy community spirit as well as high concern regarding malaria and its importation and there is currently effective malaria passive case detection and management. Conducting malaria screening at ports and airports would be acceptable to the community.ConclusionA robust surveillance-response system is essential when moving towards malaria elimination. Many factors contribute positively towards the feasibility of an RDT based malaria surveillance system in Isabel Province. Due to financial and logistical restraints local health authorities have concluded that a system of community-based vigilance to identify new arrivals in villages and direct them to have malaria testing is more feasible than formal screening at ports and airports. A surveillance response system to prevent introduction of malaria into Isabel Province can be integrated into the National Malaria Control Programme provided the operational steps are carefully planned with regards to human and financial resources.

An indigenous malaria transmission in the outskirts of Addis Ababa, Akaki Town and its environs

Background: In recent years malaria is becoming endemic in highland areas beyond its previously known upper limit of transmission. Assessment of the situation of the disease in such areas is necessary in order to institute appropriate control activities. Objectives: The objectives of the study were to determine the prevalence of malaria, the parasite species involved and Anopheles species responsible in local malaria transmission. Methods: A systematic sampling technique was used to select survey households. Blood films were collected monthly between October and December 1999 from all household members by a trained and experienced laboratory technician. Larval and adult mosquitoes were monthly collected using different methods from September 1999 to October 2000. Results: Among 2136 examined blood films, 78(3.7%) of them were malaria positive of which 54(69%) were due to Plasmodium vivax and 24 (31%) due to P. falciparum. Anopheles gambiae s. l. (presumably An. arabiensis) and An. christyi were the dominant man-biting species, with the former being the major vector in the area. Both these species were found to be more of exophagic and active in the early evening, unlike An. pharoensis, which showed an endophagic tendency. Conclusion: This study indicated that indigenous transmission of malaria occurs in the study area. Transmission is reckoned to be maintained by low density of vector species for short period of time under favorable conditions. Therefore, the acquisition of communal immunity is interrupted by long duration of non-malaria season leading to the occurrence of recurrent malaria epidemics. [Ethiop.J.Health Dev. 2004;18(1):2-7]

Geographic Information System in Malaria Surveillance: Mosquito Breeding and Imported Cases in Israel, 1992

Although a significant resurgence of malaria in Israel is unlikely at present, the risk for a localized outbreak of malaria cases due to infection of local anopheline mosquitoes by imported cases does exist. A national computerized surveillance system of breeding sites of Anopheles mosquitoes and imported malaria cases was established in 1992 using a geographic information system (GIS). Distances between population centers and breeding sites were calculated, and maps associating epidemiologic and entomologic data were generated. Risk of malaria transmission was assessed with consideration of vectorial capacity and flight range of each Anopheles species. The GIS-based surveillance system ensures that if a localized outbreak does occur, it will be associated rapidly with a likely breeding site, a specific Anopheles vector, and a probable human source, so that prompt control measures can be most efficiently targeted. This cost-effective GIS-based surveillance system can be expanded and adapted for countries with indigenous malaria transmission.