bims-mosdis 2023-03-12 papers

bims-mosdis

Biomed News

on Mosquito distribution and disease

Issue of 2023–03–12
nine papers selected by
Richard Halfpenny, Staffordshire University

Current evidences of the efficacy of mosquito mass-trapping interventions to reduce Aedes aegypti and Aedes albopictus populations and Aedes-borne transmission.
Impact of regional climate change on the mosquito vector Aedes albopictus in a tropical island environment: La Réunion.
Resistance to Pyrethroids in the Malaria Vector Anopheles albimanus in Two Important Villages in the Soconusco Region of Chiapas, Mexico, 2022.
Release of sterile Aedes aegypti mosquitoes: chilling effect on mass-reared males survival and escape ability and on irradiated males sexual competitiveness.
International modified Delphi study on malaria preventive behaviour: new themes, contexts and framework for future research on Plasmodium knowlesi malaria.
Malaria in the eco-epidemiological region of the Colombian Caribbean, 1960-2019.
Usutu virus: An emerging flavivirus with potential threat to public health in Africa: Nigeria as a case study.
Malaria knowledge, attitude, and practice among communities involved in a seasonal malaria chemoprevention study in Nanyumbu and Masasi districts, Tanzania.
Effectiveness of Dengue Awareness Calendar on Indigenous Population: Impact on Knowledge, Belief and Practice.

PLoS Negl Trop Dis. 2023 Mar 06. 17(3): e0011153

Current evidences of the efficacy of mosquito mass-trapping interventions to reduce Aedes aegypti and Aedes albopictus populations and Aedes-borne transmission.

Ali Jaffal, Johanna Fite, Thierry Baldet, Pascal Delaunay, Frédéric Jourdain, Ronald Mora-Castillo, Marie-Marie Olive, David Roiz.

BACKGROUND: Over the past decades, several viral diseases transmitted by Aedes mosquitoes-dengue, chikungunya, Zika-have spread outside of tropical areas. To limit the transmission of these viruses and preserve human health, the use of mosquito traps has been developed as a complement or alternative to other vector control techniques. The objective of this work was to perform a systematic review of the existing scientific literature to assess the efficacy of interventions based on adult mosquito trap to control Aedes population densities and the diseases they transmit worldwide.
METHODS AND FINDINGS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted using the PubMed and Scopus databases. Among the 19 selected papers, lethal ovitraps were used in 16 studies, host-seeking female traps in 3 studies. Furthermore, 16 studies focused on the control of Ae. aegypti. Our review showed great heterogeneity in the indicators used to assess trap efficacy: e.g., the number of host-seeking females, the number of gravid females, the proportion of positive containers, the viral infection rate in female mosquitoes or serological studies in residents. Regardless of the type of studied traps, the results of various studies support the efficacy of mass trapping in combination with classical integrated vector control in reducing Aedes density. More studies with standardized methodology, and indicators are urgently needed to provide more accurate estimates of their efficacy.
CONCLUSIONS: This review highlights gaps in the demonstration of the efficacy of mass trapping of mosquitoes in reducing viral transmission and disease. Thus, further large-scale cluster randomized controlled trials conducted in endemic areas and including epidemiological outcomes are needed to establish scientific evidence for the reduction of viral transmission risk by mass trapping targeting gravid and/or host-seeking female mosquitoes.

DOI: https://doi.org/10.1371/journal.pntd.0011153
Sci Total Environ. 2023 Mar 06. pii: S0048-9697(23)01100-2. [Epub ahead of print]875 162484

Impact of regional climate change on the mosquito vector Aedes albopictus in a tropical island environment: La Réunion.

K Lamy, A Tran, T Portafaix, M D Leroux, T Baldet.

  The recent expansion of Aedes albopictus across continents in both tropical and temperate regions and the exponential growth of dengue cases over the past 50 years represent a significant risk to human health. Although climate change is not the only factor responsible for the increase and spread of dengue cases worldwide, it might increase the risk of disease transmission at global and regional scale. Here we show that regional and local variations in climate can induce differential impacts on the abundance of Ae. albopictus. We use the instructive example of Réunion Island with its varied climatic and environmental conditions and benefiting from the availability of meteorological, climatic, entomological and epidemiological data. Temperature and precipitation data based on regional climate model simulations (3 km × 3 km) are used as inputs to a mosquito population model for three different climate emission scenarios. Our objective is to study the impact of climate change on the life cycle dynamics of Ae. albopictus in the 2070-2100 time horizon. Our results show the joint influence of temperature and precipitation on Ae. albopictus abundance as a function of elevation and geographical subregion. At low-elevations areas, decreasing precipitation is expected to have a negative impact on environmental carrying capacity and, consequently, on Ae. albopictus abundance. At mid- and high-elevations, decreasing precipitation is expected to be counterbalanced by a significant warming, leading to faster development rates at all life stages, and consequently increasing the abundance of this important dengue vector in 2070-2100.

Keywords:  Aedes albopictus; Climate change; Regional climate models; Reunion Island; Tropical environment; Vector-borne diseases

DOI:  https://doi.org/10.1016/j.scitotenv.2023.162484
Int J Environ Res Public Health. 2023 Feb 27. pii: 4258. [Epub ahead of print]20(5):

Resistance to Pyrethroids in the Malaria Vector Anopheles albimanus in Two Important Villages in the Soconusco Region of Chiapas, Mexico, 2022.

Francisco Solis-Santoyo, Cuauhtémoc Villarreal-Treviño, Alma D López-Solis, Lilia González-Cerón, José Cruz Rodríguez-Ramos, Farah Z Vera-Maloof, Rogelio Danis-Lozano, Rosa Patricia Penilla-Navarro.

  Chiapas State comprises the largest malaria foci from Mexico, and 57% of the autochthonous cases in 2021, all with Plasmodium vivax infections, were reported in this State. Southern Chiapas is at constant risk of cases imported due to migratory human flow. Since chemical control of vector mosquitoes is the main entomological action implemented for the prevention and control of vector-borne diseases, this work aimed to investigate the susceptibility of Anopheles albimanus to insecticides. To this end, mosquitoes were collected in cattle in two villages in southern Chiapas in July-August 2022. Two methods were used to evaluate the susceptibility: the WHO tube bioassay and the CDC bottle bioassay. For the latter, diagnostic concentrations were calculated. The enzymatic resistance mechanisms were also analyzed. CDC diagnostic concentrations were obtained; 0.7 μg/mL deltamethrin, 12 μg/mL permethrin, 14.4 μg/mL malathion, and 2 μg/mL chlorpyrifos. Mosquitoes from Cosalapa and La Victoria were susceptible to organophosphates and to bendiocarb, but resistant to pyrethroids, with mortalities between 89% and 70% (WHO), and 88% and 78% (CDC), for deltamethrin and permethrin, respectively. High esterase levels are suggested as the resistance mechanism involved in the metabolism of pyrethroids in mosquitoes from both villages. Mosquitoes from La Victoria might also involve cytochrome P450. Therefore, organophosphates and carbamates are suggested to currently control An. albimanus. Its use might reduce the frequency of resistance genes to pyrethroids and vector abundance and may impede the transmission of malaria parasites.

Keywords:  Anopheles albimanus; esterases; forced oviposition; imported malaria; insecticide resistance; pyethroids

DOI:  https://doi.org/10.3390/ijerph20054258
Sci Rep. 2023 Mar 07. 13(1): 3797

Release of sterile Aedes aegypti mosquitoes: chilling effect on mass-reared males survival and escape ability and on irradiated males sexual competitiveness.

Génesis Alejandra Sánchez-Aldana-Sánchez, Pablo Liedo, J Guillermo Bond, Ariane Dor.

In the sterile insect technique, it is important to measure the impact of mass-rearing and handling of sterile males to allow a successful control of the target wild population. This study evaluates the effect of pre-release chilling on the survival, escape ability, and sexual competitiveness of male Aedes aegypti. To determine survival and escape ability, mosquitoes were chilled at 4 °C using four different treatments of either one exposure (25 min) or two consecutive exposures (25 + 25 min, 25 + 50 min, 25 + 100 min). For sexual competitiveness, two different treatments were evaluated, chilling for 25 min once and twice. Results showed that the longest exposure to chilling caused a significant reduction of survival time, from 67 to 54 days. Escape ability was reduced by the first chilling from 25 to 7% and with the second chilling, it was reduced from 30 to 24% in the control to 4.9, 2.0 and 0.5% for 25, 50 and 100 min, respectively. Sexual competitiveness index was reduced from 1.16 in the control, to 0.32 and - 0.11 for treatments involving one and two chilling periods, respectively. It is recommended to increase the chilling temperature and reduce the exposure time to reduce the harmful effects on sterile males.

DOI: https://doi.org/10.1038/s41598-023-30722-9
BMJ Open. 2023 Mar 10. 13(3): e067451

International modified Delphi study on malaria preventive behaviour: new themes, contexts and framework for future research on Plasmodium knowlesi malaria.

Nurul Athirah Naserrudin, Rozita Hod, Mohammad Saffree Jeffree, Kamruddin Ahmed, Mohd Rohaizat Hassan.

   INTRODUCTION: Plasmodium knowlesi malaria is a non-human simian malaria that threatens Southeast Asian rural communities. Studies indicate that non-compliant bednet usage, travelling into the forest and working as farmers and rubber tappers put communities at risk for infection. Despite guidelines, malaria incidence increases yearly and has become a public health concern. In addition to research gaps addressing factors that influence malaria prevention behaviour in these communities, there are no specific guidelines to facilitate strategies against the threat of P. knowlesi malaria.
METHOD: To examine potential factors that influence malaria-prevention behaviour in communities exposed to P. knowlesi malaria, 12 malaria experts participated in a modified Delphi study; every participant maintained their anonymity throughout the study. Three Delphi rounds were conducted via different online platforms between 15 November 2021 and 26 February 2022, and consensus was achieved when 70% of the participants agreed on a particular point with a 4-5 median. The results from the open-ended questions were then subjected to thematic analysis, and the dataset generated by this study was analysed using a deductive and inductive approach.
RESULTS: After a systematic, iterative process, knowledge and belief, social support, cognitive and environmental factors, past experience as a malaria patient, and the affordability and feasibility of a given intervention were critical contributors to malaria-prevention behaviour.
CONCLUSION: Future research on P. knowlesi malaria could adapt this study's findings for a more nuanced understanding of factors that influence malaria-prevention behaviour and improve P. knowlesi malaria programmes based on the expert consensus.

Keywords:  EPIDEMIOLOGY; Epidemiology; INFECTIOUS DISEASES; PUBLIC HEALTH; Public health; TROPICAL MEDICINE

DOI:  https://doi.org/10.1136/bmjopen-2022-067451
Rev Peru Med Exp Salud Publica. 2022 Oct-Dec;39(4):39(4): 463-468

Malaria in the eco-epidemiological region of the Colombian Caribbean, 1960-2019.

Luis Acuña-Cantillo, Mario J Olivera, Julio Cesar Padilla-Rodríguez.

OBJECTIVES.: Motivation for the study: the information available on the epidemiology of malaria in the Colombian Caribbean region is incomplete, poorly systematized and its dissemination is limited. This has led to a lack of knowledge of its magnitude and a low perception of its importance as a public health problem. Main findings: the behavior of malaria is endemic-epidemic, with low to very low transmission, focused and with irregular outbreaks. Plasmodium vivax infections predominate. Implications: the results of this study contribute to improve evidence-based decision making for the implementation of malaria eradication plans. Malaria has a heterogeneous and variable behavior among Colombian regions. In order to establish its epidemiological behavior in the Colombian Caribbean region between 1960 and 2019, we carried out an observational, descriptive and retrospective study based on records from the Ministry of Health and other secondary sources. We defined epidemiological variables and used measures of frequency and central tendency. A total of 155,096 cases were registered. The decades with the highest number of cases were 1990-1999 (20.5%) and 1980-1989 (18.9%). The average number of cases per decade was 25,849.3. The highest parasite rates were recorded in 1970 (3.3 per 1000 population) and 1981 (3.9 per 1000 population). Plasmodium vivax was the most frequent species and most of the burden by age group was found in people under 29 years of age, between 2010-2019. Malaria showed an endemic-epidemic pattern of low and very low transmission intensity, with a decreasing trend.

DOI: https://doi.org/10.17843/rpmesp.2022.394.11359
Front Vet Sci. 2023 ;10 1115501

Usutu virus: An emerging flavivirus with potential threat to public health in Africa: Nigeria as a case study.

Olalekan Chris Akinsulie, Ridwan Olamilekan Adesola, Adetolase Bakre, Oluwawemimo Oluseun Adebowale, Richard Adeleke, Seto Charles Ogunleye, Ifeoluwa Peace Oladapo.

  Usutu virus (USUV) is an arthropod-borne virus (arbovirus) of the flaviviridae family (genus Flavivirus) which belong to the Japanese encephalitis virus complex. Culex mosquitoes have been implicated in the transmission of this pathogen. The major susceptible hosts of USUV are migratory birds, thereby potentiating its ability to spread from one region to another globally. Nigeria has the largest economy in Africa with a significant percentage of the gross domestic product relying on the agricultural and animal production industry. This review explores the zoonotic potentials of the virus in Africa, especially Nigeria, with special focus on the devastating sequelae this might lead to in the future if necessary precautionary policies are not enacted and adopted to bolster the surveillance system for mosquito-borne viruses.

Keywords:  Culex mosquitoes; Usutu virus; flavivirus; migratory birds; public health

DOI:  https://doi.org/10.3389/fvets.2023.1115501
Front Public Health. 2023 ;11 976354

Malaria knowledge, attitude, and practice among communities involved in a seasonal malaria chemoprevention study in Nanyumbu and Masasi districts, Tanzania.

Billy Ngasala, Richard O Mwaiswelo, Frank Chacky, Fabrizio Molteni, Ally Mohamed, Samwel Lazaro, Bushukatale Samuel, Bruno P Mmbando.

   Background: Utilization of malaria interventions is influenced by, among other things, the level of knowledge and attitude that the community has toward the infection as well as the available interventions. This study assessed malaria knowledge, attitudes, and practices on malaria infection and interventions in Masasi and Nanyumbu districts, Tanzania.
Methods: A community-based cross-sectional survey was conducted between August and September 2020, among the heads of households having at least one under-five child. Information on knowledge, attitudes, and practices on malaria infection and interventions was gathered from the heads of the households using a structured questionnaire. The knowledge level was classified into low, moderate, and high. Attitudes were classified into positive and negative, whereas the practices were classified into good and poor. Children aged between 3 and 59 months were screened for malaria infection using a malaria rapid diagnostic test (mRDT). The proportion of the households' heads with high level of knowledge was the primary outcome. Proportions were compared using Chi-square or fisher's test, and logistic regression analysis was used as appropriate.
Results: A total of 1,556 household heads were interviewed, 1,167 (75.00%) were male, and according to marital status, 1,067 (68.57%) were couples. All the household heads had some knowledge of malaria, but 47.33% (736/1,555) and 13.83% (215/1,555) of them had moderate and high knowledge, respectively. The level of knowledge on malaria was significantly influenced by gender [adjusted odds ratio (aOR) = 0.72, 95.00% confidence interval (CI) = 0.56-0.94, p = 0.017], level of education (aOR = 1.50, 95.00% CI = 1.04-2.16, p = 0.03), and the occupation of the household head (aOR = 1.90, 95.00% CI = 1.22-2.96, p = 0.004). Majority of the households [83.87% (1,305/1,556)] had bed nets hanging on the sleeping spaces. Of the household heads possessing bed nets, 85.10% (514/604), 79.62% (586/736), and 95.35% (205/215) of them had a low, moderate, and high level of knowledge on malaria infection, respectively (trend x 2 = 31.53, p < 0.001). The majority [95.04% (1,474/1,551)] of the household heads perceived sleeping under the bed net to be beneficial. Furthermore, 15.56% (94/604), 14.67% (108/736), and 7.44% (16/215) of the household heads with low, moderate, and high knowledge, respectively, had children with malaria infection (trend x 2 = 9.172, p = 0.01).
Conclusion: The study population had a good level of knowledge about malaria infection, and a good attitude toward malaria interventions, and the majority of them were using bed nets.

Keywords:  Masasi; Nanyumbu; Tanzania; attitude; knowledge; malaria control; utilization

DOI:  https://doi.org/10.3389/fpubh.2023.976354
Healthcare (Basel). 2023 Feb 21. pii: 637. [Epub ahead of print]11(5):

Effectiveness of Dengue Awareness Calendar on Indigenous Population: Impact on Knowledge, Belief and Practice.

Li Ping Wong, Arulvani Rajandra, Juraina Abd Jamil, Sazaly AbuBakar, Yulan Lin, Hai Yen Lee.

   BACKGROUND: Dengue is prevalent among the indigenous community due to impoverished living conditions near the forest fringe areas and lack of health awareness. The study aims to determine the effect of a dengue awareness calendar on knowledge, belief, and practices (KBP) among the indigenous population.
METHOD: A cross-sectional study was conducted in nine selected indigenous villages in Selangor, Malaysia. A dengue awareness calendar was distributed to the indigenous communities after pre-intervention. The KBP scores were compared between the pre-and post-intervention.
RESULT: A total of 609 paired responses were obtained. Knowledge, perceived severity, cues to action, self-efficacy, and prevention practices were significantly improved after the intervention (p > 0.00). Participants with primary (Odds Ratio (OR) 2.627; 95% CI 1.338-5.160) and secondary level education (OR 2.263; 95% Cl 1.126-4.550) reported a high increment in practices score. High increments in dengue knowledge scores (OR 2.190; 95% CI 1.521-3.757, p < 0.00) were significantly more likely to report a high increment in practices score. Housewives (OR 0.535; 95% Cl 0.289-0.950), perceived severity (OR 0.349; 95% CI 0.184-0.662), and perceived susceptibility (OR 0.474; 95% CI 0.286-0.785) were significantly less likely to report an increment in prevention practices score.
CONCLUSION: Findings inferred that the dengue awareness calendar significantly improved knowledge and practices. Our findings revealed the effectiveness of the dengue awareness calendar in dengue prevention among indigenous communities.

Keywords:  belief; dengue fever; indigenous community; knowledge; prevention practices

DOI:  https://doi.org/10.3390/healthcare11050637