Effects of Climate Change and Heterogeneity of Local Climates оn the Development of Malaria Parasite (Plasmodium vivax) in Moscow Megacity Region

Evaluation of Outbreak Preparedness to Prevent the Reintroduction of Malaria in Ramanagara District: A Descriptive Epidemiological Study

Background Malaria is a vector-borne disease transmitted by female anopheline mosquitoes. It is also a multidimensional disease influenced by social factors such as poor environmental conditions and awareness gaps. India has witnessed a substantial reduction in malaria cases and has declared three regions as malaria-free, with Karnataka being one of the states. However, Karnataka witnesses significant population movement and migration, which influences the spread of malaria. Ramanagara, a district in Karnataka, reported zero indigenous cases over the past three years. Hence, we selected this district to evaluate outbreak preparedness to prevent the reintroduction of malaria. This choice underscores the district's significance as a valuable model for preventing the reintroduction of malaria. Methodology Baseline survey data on malaria cases and vector survey data were evaluated for the period spanning 2018 to 2022. The data were gathered from both the regional office and the Ramanagara district health office. In addition to the documenting system, because there was no regular submission of Form-P and Form-L of the Integrated Disease Surveillance Project and Integrated Health Information Platform from the private sector, to complete the missing data, a cross-sectional study was conducted among private sector practitioners and pharmacies in Ramanagara from April 2023 to June 2023. Data was collected via interviews using a malaria surveillance assessment toolkit sourced from the National Centre for Vector Borne Diseases Control and World Health Organization protocols to assess six core areas of malaria elimination. Data collected via interviews were compiled in MS Excel and analyzed using SPSS Statistics for Windows, version 26.0 (IBM Corp., Armonk, NY, USA). Results Malaria control measures in the selected district achieved >80% coverage with notable improvements in the National Health Mission-National Vector Borne Disease Control Programme fund utilization, logistics availability, and physical performance over the past five years. The Annual Parasite Index was <1 at 0.0061 in 2018 and 0.0017 in 2022. The annual blood examination rate was consistently >10 from 22.05 in 2018 to 24.36 in 2022. The primary vectors identified were Anopheles culicifacies and Anopheles stephensi. In 2018, there were six cases of Plasmodium vivax and one case of Plasmodium falciparum reported as imported cases. In 2021 and 2022, two cases of P. vivax were reported. Notably, there were no instances of mixed infections or indigenous cases documented from 2018 to 2022 Conclusions Although the level of outbreak preparedness in the region is satisfactory, the effectiveness of vector control measures appears to be lacking. Increased government funding is needed along with comprehensive training and workshops for healthcare workers. Adequate financial resources and enhanced skills among healthcare workers are crucial to reinforce the existing efforts to control vectors and prevent potential outbreaks effectively.

Teles CB, Medeiros JF, Pereira DB, Vinetz JM, Gazzinelli RT, Araújo MS. Transmission-blocking activity of antimalarials for Plasmodium vivax malaria in Anopheles darlingi

Malaria is caused by parasite of the genus Plasmodium and is still one of the most important infectious diseases in the world. Several biological characteristics of Plasmodium vivax contribute to the resilience of this species, including early gametocyte production, both of which lead to efficient malaria transmission to mosquitoes. This study evaluated the impact of currently used drugs on the transmission of P. vivax. Participants received one of the following treatments for malaria: i) chloroquine [10 mg/kg on day 1 and 7.5 mg/kg on day 2 and 3] co-administered with Primaquine [0.5 mg/kg/day for 7 days]; ii) Chloroquine [10 mg/kg on day 1 and 7.5 mg/kg on day 2 and 3] co-administered with one-dose of Tafenoquine [300 mg on day 1]; and iii) Artesunate and Mefloquine [100 mg and 200 mg on day 1, 2 and 3] co-administered with Primaquine [0.5 mg/kg/day for 14 days]. Patient blood was collected before treatment and 4 h, 24 h, 48 h and 72 h after treatment. The blood was used to perform a direct membrane feeding assay (DMFA) using Anopheles darlingi mosquitoes. The results showed 100% inhibition of the mosquito infection after 4 h using ASMQ+PQ, after 24 h for the combination of CQ+PQ and 48 h using CQ+TQ. The density of gametocytes declined over time in all treatment groups, although the decline was more rapid in the ASMQ+PQ group. In conclusion, it was possible to demonstrate the transmission-blocking efficacy of the malaria vivax treatment and that ASMQ+PQ acts faster than the two other treatments.

Simulation of the potential impact of climate change on malaria incidence using artificial neural networks (ANNs)

Climate change can increase the spread of infectious diseases and public health concerns. Malaria is one of the endemic infectious diseases of Iran, whose transmission is strongly influenced by climatic conditions. The effect of climate change on malaria in the southeastern Iran from 2021 to 2050 was simulated by using artificial neural networks (ANNs). Gamma test (GT) and general circulation models (GCMs) were used to determine the best delay time and to generate the future climate model under two distinct scenarios (RCP2.6 and RCP8.5). To simulate the various impacts of climate change on malaria infection, ANNs were applied using daily collected data for 12 years (from 2003 to 2014). The future climate of the study area will be hotter by 2050. The simulation of malaria cases elucidated that there is an intense increasing trend in malaria cases under the RCP8.5 scenario until 2050, with the highest number of infections occurring in the warmer months. Rainfall and maximum temperature were identified as the most influential input variables. Optimum temperatures and increased rainfall provide a suitable environment for the transmission of parasites and cause an intense increase in the number of infection cases with a delay of approximately 90 days. ANNs were introduced as a practical tool for simulating the impact of climate change on the prevalence, geographic distribution, and biological activity of malaria and for estimating the future trend of the disease in order to adopt protective measures in endemic areas.

Plasmodium vivax: the potential obstacles it presents to malaria elimination and eradication

Initiatives to eradicate malaria have a good impact on P. falciparum malaria worldwide. P. vivax, however, still presents significant difficulties. This is due to its unique biological traits, which, in comparison to P. falciparum, pose serious challenges for malaria elimination approaches. P. vivax's numerous distinctive characteristics and its ability to live for weeks to years in liver cells in its hypnozoite form, which may elude the human immune system and blood-stage therapy and offer protection during mosquito-free seasons. Many malaria patients are not fully treated because of contraindications to primaquine use in pregnant and nursing women and are still vulnerable to P. vivax relapses, although there are medications that could radical cure P. vivax. Additionally, due to CYP2D6's highly variable genetic polymorphism, the pharmacokinetics of primaquine may be impacted. Due to their inability to metabolize PQ, some CYP2D6 polymorphism alleles can cause patients to not respond to treatment. Tafenoquine offers a radical treatment in a single dose that overcomes the potentially serious problem of poor adherence to daily primaquine. Despite this benefit, hemolysis of the early erythrocytes continues in individuals with G6PD deficiency until all susceptible cells have been eliminated. Field techniques such as microscopy or rapid diagnostic tests (RDTs) miss the large number of submicroscopic and/or asymptomatic infections brought on by reticulocyte tropism and the low parasitemia levels that accompany it. Moreover, P. vivax gametocytes grow more quickly and are much more prevalent in the bloodstream. P. vivax populations also have a great deal of genetic variation throughout their genome, which ensures evolutionary fitness and boosts adaptation potential. Furthermore, P. vivax fully develops in the mosquito faster than P. falciparum. These characteristics contribute to parasite reservoirs in the human population and facilitate faster transmission. Overall, no genuine chance of eradication is predicted in the next few years unless new tools for lowering malaria transmission are developed (i.e., malaria elimination and eradication). The challenging characteristics of P. vivax that impede the elimination and eradication of malaria are thus discussed in this article.

Reimagining zoonotic malaria control in communities exposed to Plasmodium knowlesi infection

Plasmodium knowlesi malaria infection in humans has been reported throughout southeast Asia. The communities at risk are those living in areas where Macaque monkeys and Anopheles mosquito are present. Zoonotic malaria control is challenging due to the presence of the reservoir host and the possibility of human-vector-human transmission. Current control measures, including insecticide-treated nets (ITNs) and indoor residual spraying (IRS), are insufficient to address this threat due to gaps in protection associated with outdoor and early evening vector biting and social and economic activities, such as agricultural and forest work. Understanding the challenges faced by affected communities in preventing mosquito bites is important for reducing disease transmission. This opinion paper discusses opportunities to improve P. knowlesi malaria control through understanding the challenges faced by communities at risk and increasing community engagement and ownership of control measures. The paper highlights this issue by describing how the concept of reimagining malaria can be adapted to zoonotic malaria control measures including identifying current gaps in vector control, understanding interactions between environmental, economic, and human behavioral factors, and increasing community participation in and ownership of control measures.

Global Climate Change and Human Dirofilariasis in Russia

Human dirofilariasis is a vector-borne helminth disease caused by two species of Dirofilaria: D. repens and D. immitis. The vectors of the helminth are mosquitoes in the family Culicidae. The definitive hosts of Dirofilaria are dogs and, to a lesser extent, cats. Humans are accidental hosts. Dirofilariasis has been reported in the territory of Russia since 1915. Sporadic cases of the disease have been reported occasionally, but the number of cases showed a distinct increasing trend in the late 1980s–early 1990s, when the number of cases reached several hundred in the southern territories of Russia, with geographic coordinates of 43° N–45° N. A comparison of the timing of the global trend of climate warming during the 1990s with the temporal pattern of the incidence of dirofilariasis in the territory of Russia indicated a close association between the two phenomena. At present, the northern range of Dirofilaria includes latitudes higher than 58° in both the European and Asian parts of the country. The phenomenon of climate warming in the territory of Russia has shaped the contemporary epidemiology of the disease. The emerging public health problem of dirofilariasis in Russia warrants the establishment of a comprehensive epidemiological monitoring system.

Anthology of Dirofilariasis in Russia (1915-2017)

Dirofilariasis is a helminths vector-borne disease caused by two species of Dirofolaria—D. repens and D. immitis. The former is overwhelmingly associated with human dirofilariasis. The vector of the worm are mosquitoes of the family Culicidae (largely Culex, Aedes and Anopheles). The definitive hosts of Dirofilaria are dogs and to a lesser extent cats. Humans are an accidental host. A total of 1200 human cases caused by Dirofilaria were registered in the territory of the ex-USSR during the period 1915–2016. Zonal differences have been seen in the prevalence of infected dogs and mosquitoes. Studies undertaken in the southern part of the Russian Federation (RF) revealed the prevalence of Dirofilaria in dogs to be 20.8% with wild variations of larva density. Studies carried out in the central part of the RF found that the prevalence of parasites in dogs was 4.1%. Aedes mosquitoes were infected less than Culex and Anopheles mosquitoes. The latter were infected by D. repens more often than Culex and Aedes. Zonal differences were also traced in regard to Dirofilaria prevalence in humans, thus allowing identification of three zones of risk of infection (low, moderate, and stable), reflected in a series of constructed maps. Although Dirofilariasis was known on the territory of Russia from 1915, only sporadic cases of the disease were reported occasionally. Its number was showed an increasing trend only during the 1980s–1990s, reaching the level of hundreds of cases. The majority of cases were confined to the southern parts of Russia with geographic coordinates of 43°–45° on the northern latitude. Comparison of the timing of the global trend of climate warming during the 1990s with the temporal pattern of Dirofilaria on the territory of Russia during the same period demonstrated a close association between two phenomena. With the continuous process of global climate warming, the incidence of dirofilariasis both in man and dogs goes unabated exemplified by the territorial expansion of the disease northwards and eastwards attaining the latitude of 56°–57° on the northern latitude in the European and Asian parts of Russia. It appears that within the period of the last 20–25 years, the population at risk has doubled. Under these circumstances, dirofilariases in Russia should be considered as an emerging public health problem necessitating the establishment of a comprehensive epidemiological monitoring system with strong entomological and veterinary components. Based on the results obtained, an appropriate control intervention could be developed.

Re-introduction of vivax malaria in a temperate area (Moscow region, Russia): a geographic investigation

Background

Between 1999 and 2008 Russia experienced a flare-up of transmission of vivax malaria following its massive importation with more than 500 autochthonous cases in European Russia, the Moscow region being the most affected. The outbreak waned soon after a decrease in importation in mid-2000s and strengthening the control measures. Compared with other post-eradication epidemics in Europe this one was unprecedented by its extension and duration.

Methods

The aim of this study is to identify geographical determinants of transmission. The degree of favourability of climate for vivax malaria was assessed by measuring the sum of effective temperatures and duration of season of effective infectivity using data from 22 weather stations. For geospatial analysis, the locations of each of 405 autochthonous cases detected in Moscow region have been ascertained. A MaxEnt method was used for modelling the territorial differentiation of Moscow region according to the suitability of infection re-emergence based on the statistically valid relationships between the distribution of autochthonous cases and environmental and climatic factors.

Results

In 1999–2004, in the beginning of the outbreak, meteorological conditions were extremely favourable for malaria in 1999, 2001 and 2002, especially within the borders of the city of Moscow and its immediate surroundings. The greatest number of cases occurred at the northwestern periphery of the city and in the adjoining rural areas. A significant role was played by rural construction activities attracting migrant labour, vegetation density and landscape division. A cut-off altitude of 200 m was observed, though the factor of altitude did not play a significant role at lower altitudes. Most likely, the urban heat island additionally amplified malaria re-introduction.

Conclusion

The malariogenic potential in relation to vivax malaria was high in Moscow region, albeit heterogeneous. It is in Moscow that the most favourable conditions exist for vivax malaria re-introduction in the case of a renewed importation. This recent event of large-scale re-introduction of vivax malaria in a temperate area can serve as a case study for further research.

Sensitivity of Radiative and Thermal Properties of Building Material in the Urban Atmosphere

In the context of the impact of urbanization on climate change, this work aims to evaluate the sensitivity of the thermal and radiative properties of building surfaces in urban areas to the urban heat island intensity, a local scale meteorological phenomenon. For this, variations of albedo values, emissivity, thermal conductivity and heat capacity of roofs, streets and walls were simulated through an urban scheme coupled with the BRAMS mesoscale atmospheric model for the metropolitan area of São Paulo, considering two main urban types. The simulations show that, in general, looking for cold surface situations, the change of building material can contribute to a reduction of up to 3 °C for São Paulo. In addition, the role of orientation and the typological characteristics of constructions should be taken into account. In this sense, it is expected that this work guides civil engineers and builders to search for new materials in order to reduce the effects of urbanization on the local climate.

Plasmodium infection in Kerteszia cruzii (Diptera: Culicidae) in the Atlantic tropical rain forest, southeastern Brazil

In Southeastern Brazil, Kerteszia cruzii (former Anopheles cruzii), a bromeliad mosquito species, is considered an efficient human Plasmodium spp. vector. In this region, recent studies showed asymptomatic or sub-patent Plasmodium falciparum infection. In areas of the Atlantic coast in Rio de Janeiro, Plasmodium simium infection was recently reported in both human and howler monkey. Considering that (1) few malaria cases are reported each year in areas across the tropical Atlantic rain forest in southeastern Brazil; (2) malaria elimination in Atlantic forest is challenged by circulation of P. falciparum and P. simium in humans; (3) the complexity of malaria epidemiology in this region; and (4) the public health importance of Kerteszia cruzii as a sylvatic vector; the major goal of this study is to evaluate Plasmodium infection in Ke. cruzii. Mosquito sampling collections were conducted in Esteiro do Morro and Sítio Itapuan, in Cananeia municipality, and Tapiraí municipality in Ribeira Valley, southeastern São Paulo state, Brazil. Influence of climate and landscape factors in Plasmodium infection in Ke. cruzii was addressed. Among the 1719 mosquitoes tested, 3 females collected in Sítio Itapuan and three from Tapiraí were found infected with either P. vivax or P. simium. Results of statistical analyses did not demonstrate association between Plasmodium infection in mosquito and the landscape. Mosquito infection was found in two landscape clusters, with Plasmodium detected in forest fringe mosquitoes. This finding shows that Ke. cruzii can facilitate transmission among human and non-human primates. Plasmodium falciparum was not identified in the samples analyzed. Spatiotemporal variation in local malaria incidence, low prevalence of Plasmodium, variations in humidity and temperature can explain the absence of mosquitoes infected with P. falciparum in the study.

Multi-Temporal Effects of Urban Forms and Functions on Urban Heat Islands Based on Local Climate Zone Classification

Urban forms and functions have critical impacts on urban heat islands (UHIs). The concept of a “local climate zone” (LCZ) provides a standard and objective protocol for characterizing urban forms and functions, which has been used to link urban settings with UHIs. However, only a few structure types and surface cover properties are included under the same climate background or only one or two time scales are considered with a high spatial resolution. This study assesses multi-temporal land surface temperature (LST) characteristics across 18 different LCZ types in Beijing, China, from July 2017 to June 2018. A geographic information system-based method is employed to classify LCZs based on five morphological and coverage indicators derived from a city street map and Landsat images, and a spatiotemporal fusion model is adopted to generate hourly 100-m LSTs by blending Landsat, Moderate Resolution Imaging Spectroradiometer (MODIS), and FengYun-2F LSTs. Then, annual and diurnal cycle parameters and heat island and cool island (HI or CI) frequency are linked to LCZs at annual, seasonal, monthly, and diurnal scales. Results indicate that: (1) the warmest zones are compact and mid and low-rise built-up areas, while the coolest zones are water and vegetated types; (2) compact and open high-rise built-up areas and vegetated types have seasonal thermal patterns but with different causes; (3) diurnal temperature ranges are the highest for compact and large low-rise settings but the lowest for water and dense or scattered trees; and (4) HIs are the most frequent summertime and daytime events, while CIs occur primarily during winter days, making them more or less frequent for open or compact and high- or low-rise built-up areas. Overall, the distinguishable LSTs or UHIs between LCZs are closely associated with the structure and coverage properties. Factors such as geolocation, climate, and layout also interfere with the thermal behavior. This study provides comprehensive information on how different urban forms and functions are related to LST variations at different time scales, which supports urban thermal regulation through urban design.

Asymmetric Soil Warming under Global Climate Change

Daily surface soil temperature data from 360 weather stations in China during 1962–2011 were retrieved and analyzed. The data revealed two aspects of asymmetric soil warming. Firstly, there was asymmetry between day and night in terms of increases in soil temperature. The daily maximum surface soil temperature (STmax) and daily minimum surface soil temperature (STmin) increased at rates of 0.031 and 0.055 °C/year over the 50-year interval, respectively. As a consequence of the more rapid increases in STmin, the soil diurnal temperature range (SDTR) decreased at most stations (average rate of –0.025 °C/year), with the most profound decrease in winter (–0.08 °C/year). The solar duration (SD) was positively related to SDTR and is regarded as the key underlying cause of the decreasing SDTR. Secondly, there was asymmetry between the soil and air in the temperature increase. The differences between soil and air temperature (TD) were highest in summer (2.76 °C) and smallest in winter (1.55 °C), which decreased by 0.3 °C over the study interval, this meant agricultural practice plans based on air temperature alone may be severely limited. The difference between soil temperature and air temperature reduces at night. This would facilitate the wintering of perennials in areas near the zero-contour line.