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Kenyeres Z. Drivers of autochthonous malaria cases over time: could the Central European present the African future? Malar J 2024; 23:181. [PMID: 38858778 PMCID: PMC11163750 DOI: 10.1186/s12936-024-05004-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Accepted: 05/28/2024] [Indexed: 06/12/2024] Open
Abstract
BACKGROUND Results of spatial and temporal comparison of malaria hotspots and coldspots could improve the health measures of malaria control and eradication strategies. The study aimed to reveal the spatially and temporally independent correlations between the potentially most effective background variables and the number of autochthonous malaria cases. METHODS Relationships between malaria cases and background variables were studied in 2 km × 2 km sized quadrates (10 Central European and 10 African). In addition to the current habitat structure of the African sites, annual precipitation, and annual mean temperature, data of the above parameters detected in the nineteenth and twentieth centuries and currently in the Central European sites were included in the analyses (n = 40). Mann-Whitney tests, Principal Component Analysis, and Generalized Linear Models were used for the examinations. RESULTS In addition to the apparent significant positive correlation of malaria cases with annual rainfall and mean temperature, several correlations were found for habitat parameters. The cover of marshlands in the 19th-century habitat structure of Central European quadrates was considerably the same as in the recent African ones. The extent of rural residential areas was significantly smaller in the 19th-century habitat structure of Central European quadrats than in present-day African ones. According to the revealed correlations, the surface cover of rural residential areas is the main driver of the number of autochthonous malaria cases that we can directly impact. CONCLUSIONS The study confirmed with historical comparison that not only the annual rainfall and mean temperature, the cover of marshlands and other habitats with breeding sites, but also the elements of the rural human environment play a significant role in the high number of autochthonous malaria cases, probably through the concentration and enhancing sites for vector mosquitoes. The latter confirms that a rapid urbanization process could reduce malaria cases in the most infected areas of Africa. Until the latter happens, extensive biological control of Anopheles larvae and chemical control (both outdoor and indoor) of their imagoes, further mosquito nets, repellents, and carbon dioxide traps will need to be applied more widely in the most heavily infested areas.
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Affiliation(s)
- Zoltán Kenyeres
- Acrida Conservational Research L.P., Deák F. St. 7., Tapolca, 8300, Hungary.
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Wu D, Zhu H, Wan L, Zhang J, Lin W, Sun L, Zhang H, Liu S, Cleary E, Tatem AJ, Xia J, Lai S. Imported and indigenous Plasmodium Vivax and Plasmodium Falciparum malaria in the Hubei Province of China, 2005-2019. Malar J 2023; 22:334. [PMID: 37932775 PMCID: PMC10629024 DOI: 10.1186/s12936-023-04752-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 10/11/2023] [Indexed: 11/08/2023] Open
Abstract
BACKGROUND The Hubei Province in China reported its last indigenous malaria case in September 2012, but imported malaria cases, particularly those related to Plasmodium vivax and Plasmodium falciparum, threaten Hubei's malaria-free status. This study investigated the epidemiological changes in P. vivax and P. falciparum malaria in this province to provide scientific evidence for preventing malaria resurgence. METHODS The prevalence, demographic characteristics, seasonal features, and geographical distribution of malaria were assessed using surveillance data and were compared across three stages: control stage (2005-2009) and elimination stages I (2010-2014) and II (2015-2019). RESULTS In 2005-2019, 8483 malaria cases were reported, including 5599 indigenous P. vivax cases, 275 imported P. vivax cases, 866 imported P. falciparum cases, and 1743 other cases. Imported P. falciparum cases accounted for 0.07% of all cases reported in 2005, but increased to 78.81% in 2019. Most imported P. vivax and P. falciparum malaria occurred among males, aged 21-60 years, during elimination stages I and II. The number of regions affected by imported P. falciparum and P. vivax increased markedly in Hubei from the control stage to elimination stage II. Overall, 1125 imported P. vivax and P. falciparum cases were detected from 47 other nations. Eight imported cases were detected from other provinces in China. From the control stage to elimination stage II, the number of cases of malaria imported from African countries increased, and that of cases imported from Southeast Asian countries decreased. CONCLUSIONS Although Hubei has achieved malaria elimination, it faces challenges in maintaining this status. Hence, imported malaria surveillance need to be strengthened to reduce the risk of malaria re-introduction.
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Affiliation(s)
- Dongni Wu
- Institute of Parasitic Disease Control, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China
| | - Hong Zhu
- Institute of Parasitic Disease Control, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China
| | - Lun Wan
- Institute of Parasitic Disease Control, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China
| | - Juan Zhang
- Institute of Parasitic Disease Control, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China
| | - Wen Lin
- Institute of Parasitic Disease Control, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China
| | - Lingcong Sun
- Institute of Parasitic Disease Control, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China
| | - Huaxun Zhang
- Institute of Parasitic Disease Control, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China
| | - Si Liu
- Institute of Parasitic Disease Control, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China
| | - Eimear Cleary
- WorldPop, School of Geography and Environmental Science, University of Southampton, Southampton, SO17 1BJ, UK
| | - Andrew J Tatem
- WorldPop, School of Geography and Environmental Science, University of Southampton, Southampton, SO17 1BJ, UK
| | - Jing Xia
- Institute of Parasitic Disease Control, Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China.
| | - Shengjie Lai
- WorldPop, School of Geography and Environmental Science, University of Southampton, Southampton, SO17 1BJ, UK.
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Mustufa MA, Bibi S, Raza SJ, Hasan SF, Siddiqui TR, Rakhia A, Munir MA, Merchant AA, Ahmed W. Seasonal Trends with the Comparison of Venous and Capillary Blood for Diagnosis of Malaria among Children in Karachi, Pakistan. IRANIAN JOURNAL OF PARASITOLOGY 2023; 18:342-350. [PMID: 37886248 PMCID: PMC10597885 DOI: 10.18502/ijpa.v18i3.13757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/14/2023] [Indexed: 10/28/2023]
Abstract
Background More than 250 million people are infected by malaria parasites annually while around one million children less than 5 years of age die every year due to malaria. We aimed to assess the seasonal trends and usefulness of capillary and venous blood for rapid diagnosis of malaria. Methods This cross-sectional study of 18 months duration was conducted at the National Institute of Child Health (NICH), Karachi. All patients reporting fever as chief complaint were recruited as study subjects. A semi-structured questionnaire was used to collect demographic information, presenting complaints, awareness of caregivers regarding malaria, preventive measures and history of malaria fever. Three ml Venous (2-3ml) as well as peripheral blood (3-4 drops) samples of all patients were collected for microscopy and rapid diagnostic tests (RDTs). Results Out of total 477 patients with fever Venous and Capillary Blood RDTs methods detected 33(6.9%) and 30(6.3%) as the malaria positive while Venous and Capillary Blood Microscopy detected 30(6.1%) and 32(6.7%) cases respectively. Plasmodium Vivax infection was the most prevalent (87.9%) and majority (39.39%) of the cases occurred in the quarter, July to September. Conclusion July to September is the peak season for malaria and P. Vivax (87.9%) is the predominant strain in Karachi. Venous and capillary blood are equally useful for malaria diagnosis however, convenience and less invasiveness may justify the preference of capillary blood over venous blood for early diagnosis of malaria.
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Affiliation(s)
| | - Safia Bibi
- National Institute of Health, Health Research Institute, Research Centre, National Institute of Child Health, Karachi, Pakistan
| | | | | | - Taranum Ruba Siddiqui
- National Institute of Health, Health Research Institute, Research Centre, Jinnah Post Graduate Medical Center, Karachi, Pakistan
| | - Allah Rakhia
- National Institute of Health, Health Research Institute, Research Centre, National Institute of Child Health, Karachi, Pakistan
| | - Muhammad Arif Munir
- National Institute of Health, Health Research Institute, Islamabad, Pakistan
| | | | - Waquarudin Ahmed
- National Institute of Health, Health Research Institute, Research Centre, Jinnah Post Graduate Medical Center, Karachi, Pakistan
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González-Sanz M, Berzosa P, Norman FF. Updates on Malaria Epidemiology and Prevention Strategies. Curr Infect Dis Rep 2023; 25:1-9. [PMID: 37361492 PMCID: PMC10248987 DOI: 10.1007/s11908-023-00805-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2023] [Indexed: 06/28/2023]
Abstract
Purpose of Review The objective of this review was to provide an update on recent malaria epidemiology, both globally and in non-endemic areas, to identify the current distribution and repercussions of genetically diverse Plasmodium species and summarize recently implemented intervention and prevention tools. Recent Findings Notable changes in malaria epidemiology have occurred in recent years, with an increase in the number of total cases and deaths globally during 2020-2021, in part attributed to the COVID-19 pandemic. The emergence of artemisinin-resistant species in new areas and the expanding distribution of parasites harbouring deletions of the pfhrp2/3 genes have been concerning. New strategies to curb the burden of this infection, such as vaccination, have been implemented in certain endemic areas and their performance is currently being evaluated. Summary Inadequate control of malaria in endemic regions may have an effect on imported malaria and measures to prevent re-establishment of transmission in malaria-free areas are essential. Enhanced surveillance and investigation of Plasmodium spp. genetic variations will contribute to the successful diagnosis and treatment of malaria in future. Novel strategies for an integrated One Health approach to malaria control should also be strengthened.
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Affiliation(s)
- Marta González-Sanz
- Infectious Diseases Department, National Referral Unit for Tropical Diseases, Ramón y Cajal University Hospital, IRYCIS, Universidad de Alcalá, CIBER de Enfermedades Infecciosas, Madrid, Spain
| | - Pedro Berzosa
- Malaria and Neglected Tropical Diseases Laboratory, National Centre for Tropical Medicine, Carlos III Health Institute, CIBER de Enfermedades Infecciosas, Madrid, Spain
| | - Francesca F. Norman
- Infectious Diseases Department, National Referral Unit for Tropical Diseases, Ramón y Cajal University Hospital, IRYCIS, Universidad de Alcalá, CIBER de Enfermedades Infecciosas, Madrid, Spain
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Spatio-temporal patterns of malaria in Nepal from 2005 to 2018: a country progressing towards malaria elimination. Spat Spatiotemporal Epidemiol 2023. [DOI: 10.1016/j.sste.2023.100576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Affiliation(s)
- Madeleine C Thomson
- From the Climate and Health Challenge Area, the Wellcome Trust, London (M.C.T.); and the Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, New York (L.R.S.)
| | - Lawrence R Stanberry
- From the Climate and Health Challenge Area, the Wellcome Trust, London (M.C.T.); and the Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, New York (L.R.S.)
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Baird JK, Warsame M, Recht J. Survey and Analysis of Chemoprophylaxis Policies for Domestic Travel in Malaria-Endemic Countries. Trop Med Infect Dis 2022; 7:tropicalmed7070121. [PMID: 35878133 PMCID: PMC9325288 DOI: 10.3390/tropicalmed7070121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/23/2022] [Accepted: 05/31/2022] [Indexed: 02/04/2023] Open
Abstract
The prevention of malaria in travelers with the use of antimalarials often occurs in connection with international travel to areas of significant risk of infection. Although these travelers sometimes cause outbreaks in their malaria-free home countries, the cardinal objective of prescribed chemoprophylaxis is to protect the traveler from patent malaria during travel. Here we consider the chemoprophylaxis of domestic travelers from malaria-free but -receptive areas within malaria-endemic countries. The main objective in this setting is the protection of those areas from reintroduced malaria transmission. In order to better understand policy and practices in this regard, we surveyed malaria prevention and treatment guidelines of 36 malaria-endemic countries and 2 that have recently eliminated malaria (Sri Lanka, China) for recommendations regarding malaria chemoprophylaxis for domestic travel. Among them, just 8 provided specific and positive recommendations, 1 recommended without specific guidance, and 4 advised against the practice. Most nations (25/38; 66%) did not mention chemoprophylaxis for domestic travel, though many of those did offer guidance for international travel. The few positive recommendations for domestic travel were dominated by the suppressive prophylaxis options of daily doxycycline or atovaquone-proguanil or weekly mefloquine. The incomplete protection afforded by these strategies, along with impractical dosing in connection with the typically brief domestic travel, may in part explain the broad lack of policies and practices across malaria-endemic nations regarding chemoprophylaxis.
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Affiliation(s)
- John Kevin Baird
- Eijkman-Oxford Clinical Research Unit, Eijkman Institute of Molecular Biology, Jakarta 10430, Indonesia
- The Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
- Correspondence:
| | - Marian Warsame
- School of Public Health and Social Medicine, Institute of Medicine, Gothenburg University, 41390 Gothenburg, Sweden;
| | - Judith Recht
- Independent Researcher, North Bethesda, MD 20852, USA;
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Yin J, Yan H, Li M. Prompt and precise identification of various sources of infection in response to the prevention of malaria re-establishment in China. Infect Dis Poverty 2022; 11:45. [PMID: 35436964 PMCID: PMC9014402 DOI: 10.1186/s40249-022-00968-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 04/07/2022] [Indexed: 11/10/2022] Open
Abstract
Prompt and precise diagnosis of patients is an essential component of malaria control and elimination strategies, it is even more vital for the prevention of malaria re-establishment in the post elimination phase. After eliminating malaria in China, the strategy for prevention of malaria re-establishment was updated in a timely manner from the elimination strategy focusing on each case/focus to the prevention of re-establishment focusing on timely identification of the source of infection. However, there are numerous challenges, such as the persistent large number of imported malaria cases, the long-term threat of border malaria, unknown levels of asymptomatic infections and Plasmodium falciparum HRP2/3 gene deletions, and the continuous spreading of antimalarial drug resistance. Meanwhile, the detection capacity also need to be further improved to meet the timely detection of all sources of infection, otherwise it is bound to occur introduced malaria cases and malaria re-establishment in the presence of malaria vector mosquitoes. Therefore, it is necessary to continuously strengthen the malaria detection competency at all levels, promote the research and development on the malaria parasitological testing technologies, thus improving the timely detection of various sources of infection, and preventing the re-establishment of malaria.
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Affiliation(s)
- Jianhai Yin
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 200025, China.
| | - He Yan
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 200025, China
| | - Mei Li
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 200025, China
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Kondrashin AV, Morozova LF, Stepanova EV, Turbabina NA, Maksimova MS, Morozov AE, Anikina AS, Morozov EN. Global Climate Change and Human Dirofilariasis in Russia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19053096. [PMID: 35270788 PMCID: PMC8910145 DOI: 10.3390/ijerph19053096] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/02/2022] [Accepted: 03/04/2022] [Indexed: 02/05/2023]
Abstract
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.
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Affiliation(s)
- Anatoly V. Kondrashin
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector-Borne Diseases, Sechenov University, 119435 Moscow, Russia; (A.V.K.); (L.F.M.); (E.V.S.); (N.A.T.); (M.S.M.); (A.E.M.); (A.S.A.)
| | - Lola F. Morozova
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector-Borne Diseases, Sechenov University, 119435 Moscow, Russia; (A.V.K.); (L.F.M.); (E.V.S.); (N.A.T.); (M.S.M.); (A.E.M.); (A.S.A.)
| | - Ekaterina V. Stepanova
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector-Borne Diseases, Sechenov University, 119435 Moscow, Russia; (A.V.K.); (L.F.M.); (E.V.S.); (N.A.T.); (M.S.M.); (A.E.M.); (A.S.A.)
| | - Natalia A. Turbabina
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector-Borne Diseases, Sechenov University, 119435 Moscow, Russia; (A.V.K.); (L.F.M.); (E.V.S.); (N.A.T.); (M.S.M.); (A.E.M.); (A.S.A.)
| | - Maria S. Maksimova
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector-Borne Diseases, Sechenov University, 119435 Moscow, Russia; (A.V.K.); (L.F.M.); (E.V.S.); (N.A.T.); (M.S.M.); (A.E.M.); (A.S.A.)
| | - Aleksandr E. Morozov
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector-Borne Diseases, Sechenov University, 119435 Moscow, Russia; (A.V.K.); (L.F.M.); (E.V.S.); (N.A.T.); (M.S.M.); (A.E.M.); (A.S.A.)
| | - Alina S. Anikina
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector-Borne Diseases, Sechenov University, 119435 Moscow, Russia; (A.V.K.); (L.F.M.); (E.V.S.); (N.A.T.); (M.S.M.); (A.E.M.); (A.S.A.)
| | - Evgeny N. Morozov
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector-Borne Diseases, Sechenov University, 119435 Moscow, Russia; (A.V.K.); (L.F.M.); (E.V.S.); (N.A.T.); (M.S.M.); (A.E.M.); (A.S.A.)
- Department of Tropical, Parasitic Diseases and Disinfectology, Russian Medical Academy of Continuous Professional Education, 125993 Moscow, Russia
- Correspondence:
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Shartova N, Mironova V, Zelikhina S, Korennoy F, Grishchenko M. Spatial patterns of West Nile virus distribution in the Volgograd region of Russia, a territory with long-existing foci. PLoS Negl Trop Dis 2022; 16:e0010145. [PMID: 35100289 PMCID: PMC8803152 DOI: 10.1371/journal.pntd.0010145] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 01/05/2022] [Indexed: 11/25/2022] Open
Abstract
Southern Russia remains affected by West Nile virus (WNV). In the current study, we identified the spatial determinants of WNV distribution in an area with endemic virus transmission, with special reference to the urban settings, by mapping probable points of human infection acquisition and points of virus detection in mosquitoes, ticks, birds, and mammals during 1999-2016. The suitability of thermal conditions for extrinsic virus replication was assessed based on the approach of degree-day summation and their changes were estimated by linear trend analysis. A generalized linear model was used to analyze the year-to-year variation of human cases versus thermal conditions. Environmental suitability was determined by ecological niche modelling using MaxEnt software. Human population density was used as an offset to correct for possible bias. Spatial analysis of virus detection in the environment showed significant contributions from surface temperature, altitude, and distance from water bodies. When indicators of location and mobility of the human population were included, the relative impact of factors changed, with roads becoming most important. When the points of probable human case infection were added, the percentage of leading factors changed only slightly. The urban environment significantly increased the epidemic potential of the territory and created quite favorable conditions for virus circulation. The private building sector with low-storey houses and garden plots located in the suburbs provided a connection between urban and rural transmission cycles.
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Affiliation(s)
- Natalia Shartova
- Faculty of Geography, Lomonosov Moscow State University, Moscow, Russia
| | - Varvara Mironova
- Faculty of Geography, Lomonosov Moscow State University, Moscow, Russia
| | | | - Fedor Korennoy
- FGBI Federal Center for Animal Health (FGBI ARRIAH), Vladimir, Russia
| | - Mikhail Grishchenko
- Faculty of Geography, Lomonosov Moscow State University, Moscow, Russia
- Faculty of Geography and Geoinformatics, HSE University, Moscow, Russia
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Bellin N, Calzolari M, Callegari E, Bonilauri P, Grisendi A, Dottori M, Rossi V. Geometric morphometrics and machine learning as tools for the identification of sibling mosquito species of the Maculipennis complex (Anopheles). INFECTION GENETICS AND EVOLUTION 2021; 95:105034. [PMID: 34384936 DOI: 10.1016/j.meegid.2021.105034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/28/2021] [Accepted: 08/07/2021] [Indexed: 11/29/2022]
Abstract
Geometric morphometrics allows researchers to use the specific software to quantify and to visualize morphological differences between taxa from insect wings. Our objective was to assess wing geometry to distinguish four Anopheles sibling species of the Maculipennis complex, An. maculipennis s. s., An. daciae sp. inq., An. atroparvus and An. melanoon, found in Northern Italy. We combined the geometric morphometric approach with different machine learning alghorithms: support vector machine (SVM), random forest (RF), artificial neural network (ANN) and an ensemble model (EN). Centroid size was smaller in An. atroparvus than in An. maculipennis s. s. and An. daciae sp. inq. Principal component analysis (PCA) explained only 33% of the total variance and appeared not very useful to discriminate among species, and in particular between An. maculipennis s. s. and An. daciae sp. inq. The performance of four different machine learning alghorithms using procrustes coordinates of wing shape as predictors was evaluated. All models showed ROC-AUC and PRC-AUC values that were higher than the random classifier but the SVM algorithm maximized the most metrics on the test set. The SVM algorithm with radial basis function allowed the correct classification of 83% of An. maculipennis s. s. and 79% of An. daciae sp. inq. ROC-AUC analysis showed that three landmarks, 11, 16 and 15, were the most important procrustes coordinates in mean wing shape comparison between An. maculipennis s. s. and An. daciae sp. inq. The pattern in the three-dimensional space of the most important procrustes coordinates showed a clearer differentiation between the two species than the PCA. Our study demonstrated that machine learning algorithms could be a useful tool combined with the wing geometric morphometric approach.
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Affiliation(s)
- Nicolò Bellin
- University of Parma, Department of Chemistry, Life Sciences and Environmental Sustainability, Parco Area delle Scienze, 11/A, 43124 Parma, Italy.
| | - Mattia Calzolari
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "B. Ubertini" (IZSLER), Brescia, Italy
| | - Emanuele Callegari
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "B. Ubertini" (IZSLER), Brescia, Italy
| | - Paolo Bonilauri
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "B. Ubertini" (IZSLER), Brescia, Italy
| | - Annalisa Grisendi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "B. Ubertini" (IZSLER), Brescia, Italy
| | - Michele Dottori
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna "B. Ubertini" (IZSLER), Brescia, Italy
| | - Valeria Rossi
- University of Parma, Department of Chemistry, Life Sciences and Environmental Sustainability, Parco Area delle Scienze, 11/A, 43124 Parma, Italy
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Chen TT, Ljungqvist FC, Castenbrandt H, Hildebrandt F, Ingholt MM, Hesson JC, Ankarklev J, Seftigen K, Linderholm HW. The spatiotemporal distribution of historical malaria cases in Sweden: a climatic perspective. Malar J 2021; 20:212. [PMID: 33933085 PMCID: PMC8088552 DOI: 10.1186/s12936-021-03744-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/20/2021] [Indexed: 12/03/2022] Open
Abstract
Background Understanding of the impacts of climatic variability on human health remains poor despite a possibly increasing burden of vector-borne diseases under global warming. Numerous socioeconomic variables make such studies challenging during the modern period while studies of climate–disease relationships in historical times are constrained by a lack of long datasets. Previous studies have identified the occurrence of malaria vectors, and their dependence on climate variables, during historical times in northern Europe. Yet, malaria in Sweden in relation to climate variables is understudied and relationships have never been rigorously statistically established. This study seeks to examine the relationship between malaria and climate fluctuations, and to characterise the spatio-temporal variations at parish level during severe malaria years in Sweden 1749–1859. Methods Symptom-based annual malaria case/death data were obtained from nationwide parish records and military hospital records in Stockholm. Pearson (rp) and Spearman’s rank (rs) correlation analyses were conducted to evaluate inter-annual relationship between malaria data and long meteorological series. The climate response to larger malaria events was further explored by Superposed Epoch Analysis, and through Geographic Information Systems analysis to map spatial variations of malaria deaths. Results The number of malaria deaths showed the most significant positive relationship with warm-season temperature of the preceding year. The strongest correlation was found between malaria deaths and the mean temperature of the preceding June–August (rs = 0.57, p < 0.01) during the 1756–1820 period. Only non-linear patterns can be found in response to precipitation variations. Most malaria hot-spots, during severe malaria years, concentrated in areas around big inland lakes and southern-most Sweden. Conclusions Unusually warm and/or dry summers appear to have contributed to malaria epidemics due to both indoor winter transmission and the evidenced long incubation and relapse time of P. vivax, but the results also highlight the difficulties in modelling climate–malaria associations. The inter-annual spatial variation of malaria hot-spots further shows that malaria outbreaks were more pronounced in the southern-most region of Sweden in the first half of the nineteenth century compared to the second half of the eighteenth century.
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Affiliation(s)
- Tzu Tung Chen
- Regional Climate Group, Department of Earth Sciences, University of Gothenburg, 405 30, Gothenburg, Sweden.
| | - Fredrik Charpentier Ljungqvist
- Department of History, Stockholm University, 106 91, Stockholm, Sweden.,Bolin Centre for Climate Research, Stockholm University, 106 91, Stockholm, Sweden.,Swedish Collegium for Advanced Study, Linneanum, Thunbergsvägen 2, 752 38, Uppsala, Sweden
| | | | - Franziska Hildebrandt
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Mathias Mølbak Ingholt
- PandemiX Center, Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Jenny C Hesson
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Johan Ankarklev
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Kristina Seftigen
- Regional Climate Group, Department of Earth Sciences, University of Gothenburg, 405 30, Gothenburg, Sweden.,Dendro Sciences Group, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Hans W Linderholm
- Regional Climate Group, Department of Earth Sciences, University of Gothenburg, 405 30, Gothenburg, Sweden
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Abstract
Cindy S Chu and co-authors review options for diagnosis, safe and radical cure, and relapse prevention of Plasmodium Vivax.
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Affiliation(s)
- Cindy S. Chu
- Shoklo Malaria Research Unit-Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Headington, Oxford, United Kingdom
- * E-mail:
| | - Nicholas J. White
- Shoklo Malaria Research Unit-Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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