bims-mosdis Biomed News
on Mosquito distribution and disease
Issue of 2022–07–10
fourteen papers selected by
Richard Halfpenny, Staffordshire University
  1. The resting behavior of malaria vectors in different ecological zones of Ghana and its implications for vector control.
  2. First comprehensive analysis of Aedes aegypti bionomics during an arbovirus outbreak in west Africa: Dengue in Ouagadougou, Burkina Faso, 2016-2017.
  3. Resistance intensity status of Anopheles gambiae s.l. species at KOLOKOPE, eastern plateau Togo: A potential site to assess new vector control tools.
  4. Characterization of the Blood-Feeding Patterns of Culex quinquefasciatus (Diptera: Culicidae) in San Bernardino County, California.
  5. Expanded geographic distribution and host preference of Anopheles gibbinsi (Anopheles species 6) in northern Zambia.
  6. City puzzles: Does urban land scape affect genetic population structure in Aedes aegypti?
  7. Evaluation of the residual efficacy and physical durability of five long-lasting insecticidal nets (LLINs) in Senegal.
  8. Malaria Prevalence and Distribution of Plasmodium Species in Southern Region of Ethiopia.
  9. Accelerating malaria elimination in Cambodia: an intensified approach for targeting at-risk populations.
  10. Status of malaria and its implications for elimination in an endemic province of South Africa: retrospective analysis.
  11. An ecological niche model to predict the geographic distribution of Haemagogus janthinomys, Dyar, 1921 a yellow fever and Mayaro virus vector, in South America.
  12. The influence of the environment and indoor residual spraying on malaria risk in a cohort of children in Uganda.
  13. Seroprevalence Rates against West Nile, Usutu, and Tick-Borne Encephalitis Viruses in Blood-Donors from North-Western Romania.
  14. Epidemiology and costs of dengue in Brazil: a systematic literature review.
  1. Parasit Vectors. 2022 Jul 08. 15(1): 246
    The resting behavior of malaria vectors in different ecological zones of Ghana and its implications for vector control.
    Akua Obeng Forson, Isaac A Hinne, Shittu B Dhikrullahi, Isaac Kwame Sraku, Abdul Rahim Mohammed, Simon K Attah, Yaw Asare Afrane.
       BACKGROUND: In sub-Saharan Africa there is widespread use of long-lasting insecticidal nets and indoor residual spraying to help control the densities of malaria vectors and decrease the incidence of malaria. This study was carried out to investigate the resting behavior, host preference and infection with Plasmodium falciparum of malaria vectors in Ghana in the context of the increasing insecticide resistance of malaria vectors in sub-Saharan Africa.
    METHODS: Indoor and outdoor resting anopheline mosquitoes were sampled during the dry and rainy seasons in five sites in three ecological zones [Sahel savannah (Kpalsogo, Pagaza, Libga); coastal savannah (Anyakpor); and forest (Konongo)]. Polymerase chain reaction-based molecular diagnostics were used to determine speciation, genotypes for knockdown resistance mutations (L1014S and L1014F) and the G119S ace1 mutation, specific host blood meal origins and sporozoite infection in the field-collected mosquitoes.
    RESULTS: Anopheles gambiae sensu lato (s.l.) predominated (89.95%, n = 1718), followed by Anopheles rufipes (8.48%, n = 162) and Anopheles funestus s.l. (1.57%, n = 30). Sibling species of the Anopheles gambiae s.l. revealed Anopheles coluzzii accounted for 63% (95% confidence interval = 57.10-68.91) and 27% (95% confidence interval = 21.66-32.55) was Anopheles gambiae s. s.. The mean resting density of An. gambiae s.l. was higher outdoors (79.63%; 1368/1718) than indoors (20.37%; 350/1718) (Wilcoxon rank sum test, Z = - 4.815, P < 0.0001). The kdr west L1014F and the ace1 mutation frequencies were higher in indoor resting An. coluzzii and An. gambiae in the Sahel savannah sites than in the forest and coastal savannah sites. Overall, the blood meal analyses revealed that a larger proportion of the malaria vectors preferred feeding on humans (70.2%) than on animals (29.8%) in all of the sites. Sporozoites were only detected in indoor resting An. coluzzii from the Sahel savannah (5.0%) and forest (2.5%) zones.
    CONCLUSIONS: This study reports high outdoor resting densities of An. gambiae and An. coluzzii with high kdr west mutation frequencies, and the presence of malaria vectors indoors despite the use of long-lasting insecticidal nets and indoor residual spraying. Continuous monitoring of changes in the resting behavior of mosquitoes and the implementation of complementary malaria control interventions that target outdoor resting Anopheles mosquitoes are necessary in Ghana.
    Keywords:  Anopheles gambiae sensu lato; Ghana; Human blood index; Insecticide resistance; Resting behavior; Sporozoite rates
    DOI:  https://doi.org/10.1186/s13071-022-05355-y
  2. PLoS Negl Trop Dis. 2022 Jul 06. 16(7): e0010059
    First comprehensive analysis of Aedes aegypti bionomics during an arbovirus outbreak in west Africa: Dengue in Ouagadougou, Burkina Faso, 2016-2017.
    Athanase Badolo, Aboubacar Sombié, Félix Yaméogo, Dimitri W Wangrawa, Aboubakar Sanon, Patricia M Pignatelli, Antoine Sanon, Mafalda Viana, Hirotaka Kanuka, David Weetman, Philip J McCall.
       BACKGROUND: Dengue's emergence in West Africa was typified by the Burkina Faso outbreaks in 2016 and 2017, the nation's largest to date. In both years, we undertook three-month surveys of Aedes populations in or near the capital city Ouagadougou, where the outbreaks were centered.
    METHODOLOGY: In 1200LG (urban), Tabtenga (peri-urban) and Goundry (rural) localities, we collected indoor and outdoor resting mosquito adults, characterized larval habitats and containers producing pupae and reared immature stages to adulthood in the laboratory for identification. All mosquito adults were identified morphologically. Host species (from which bloodmeals were taken) were identified by PCR. Generalized mixed models were used to investigate relationships between adult or larval densities and multiple explanatory variables.
    RESULTS: From samples in 1,780 houses, adult Ae. aegypti was significantly more abundant in the two urban localities (Tabtenga and 1200 LG) in both years than in the rural site (Goundry), where Anopheles spp. were far more common. Results from adult collections indicated a highly exophilic and anthropophilic (>90% bloodmeals of human origin) vector population, but with a relatively high proportion of bloodfed females caught inside houses. Habitats producing most pupae were waste tires (37% of total pupae), animal troughs (44%) and large water barrels (30%). While Stegomyia indices were not reliable indicators of adult mosquito abundance, shared influences on adult and immature stage densities included rainfall and container water level, collection month and container type/purpose. Spatial analysis showed autocorrelation of densities, with a partial overlap in adult and immature stage hotspots.
    CONCLUSION: Results provide an evidence base for the selection of appropriate vector control methods to minimize the risk, frequency and magnitude of future outbreaks in Ouagadougou. An integrated strategy combining community-driven practices, waste disposal and insecticide-based interventions is proposed. The prospects for developing a regional approach to arbovirus control in West Africa or across Africa are discussed.
    DOI:  https://doi.org/10.1371/journal.pntd.0010059
  3. Heliyon. 2022 Jun;8(6): e09770
    Resistance intensity status of Anopheles gambiae s.l. species at KOLOKOPE, eastern plateau Togo: A potential site to assess new vector control tools.
    Koffi Mensah Ahadji-Dabla, Joseph Chabi, Yawo Georges Apetogbo, Edoh Koffi, Melinda Patricia Hadi, Guillaume Koffivi Ketoh.
      According to WHO recommendations, the deployment of the next generation of Long-Lasting Insecticidal Nets (LLINs) for malaria vector control requires appropriate investigations on the insecticide resistance profile of the vector. Most of the next generation of LLINs are impregnated with a combination of pyrethroid insecticides and piperonyl butoxide (PBO), a synergist with an additional impact on the increase in the mortality rate of Anopheles gambiae s.l. (Diptera: Culicidae). Kolokopé is a cotton-growing area in the central region of Togo characterized by an intensive use of agricultural pesticides and insecticides where there is a phase II experimental hut station. For the characterization of the site, WHO susceptibility tests using diagnostic doses of ten insecticides, PBO synergist assays and intensity assays of three pyrethroids (5x and 10x) were conducted on adult female mosquitoes obtained from larvae collected around the site. Anopheles gambiae s.l. from Kolokopé showed high resistance to pyrethroids and DDT, but to a lesser extent to carbamates and organophosphates. Likewise, high intensity of resistance to pyrethroid was observed with less than 40% mortality at 10x deltamethrin, 52 and 29% mortality at 10x permethrin and 10x alphacypermethrin, respectively. Also, PBO treatment resulted in increased mortality which was higher than the mortality rate at 10x doses of pyrethroids. The high pyrethroid intensity resistance recorded at Kolokopé could be mainly due to the selection pressure on An. gambiae s.l. caused by the excessive use of insecticide in agriculture. These results can be used to assess the next generation of LLINs either in experimental hut or at a community trial.
    Keywords:  Anopheles gambiae s.l.; Next-generation LLINs; Piperonyl butoxide; Resistance intensity
    DOI:  https://doi.org/10.1016/j.heliyon.2022.e09770
  4. J Med Entomol. 2022 Jul 09. pii: tjac077. [Epub ahead of print]
    Characterization of the Blood-Feeding Patterns of Culex quinquefasciatus (Diptera: Culicidae) in San Bernardino County, California.
    Aelish Guinn, Tianyun Su, Jennifer Thieme, Min-Lee Cheng, Michelle Q Brown, Tara Thiemann.
      West Nile virus (WNV) is a zoonotic disease that is endemic in North America and is known to cause a range of symptoms from mild to life threatening in humans. Culex quinquefasciatus is one of the most prominent vectors of WNV in Southern California. The goal of this study was to identify which animal species are most fed upon by these mosquitoes in various habitats in the West Valley area of San Bernardino County, California, and determine the relationship between blood-feeding patterns and WNV activity in the region. Culex quinquefasciatus specimens were collected by West Valley Mosquito and Vector Control District during 2011 from 32 different sites. The bloodmeals of 683 individuals (92.4% of those tested) were identified using the mitochondrial gene cytochrome c oxidase 1 (COI). These bloodmeals comprised 29 vertebrate species across four different habitats. Species richness (ranging from 10 to 17) was not significantly different between habitats when rarified to account for sample size. Across habitats, the highest percentage of avian bloodmeals were taken from house sparrows (18.8-39.1%) and house finches (2.6-31.5%). Bloodmeals were identified from five mammalian species, accounting for 5.1-59.2% of bloodmeals by habitat, including humans (0-4.1%). A seasonal shift towards increased mammalian bloodmeal prevalence, specifically for domestic dog and human bloodmeals, was observed in urban habitats. The WNV activity during 2011 in San Bernardino County occurred mostly in urban and suburban areas as indicated by minimum infection rate (MIR) in Culex quinquefasciatus, notable as all human bloodmeals were identified from these two habitats.
    Keywords:   Culex quinquefasciatus ; blood-feeding; host identification; mosquito
    DOI:  https://doi.org/10.1093/jme/tjac077
  5. Malar J. 2022 Jul 03. 21(1): 211
    Expanded geographic distribution and host preference of Anopheles gibbinsi (Anopheles species 6) in northern Zambia.
    Southern Africa International Centers of Excellence for Malaria Research
       BACKGROUND: Nchelenge District in northern Zambia suffers from holoendemic malaria transmission despite a decade of yearly indoor residual spraying (IRS) and insecticide-treated net (ITN) distributions. One hypothesis for this lack of impact is that some vectors in the area may forage in the early evening or outdoors. Anopheles gibbinsi specimens were identified in early evening mosquito collections performed in this study area, and further insight was gleaned into this taxon, including characterizing its genetic identity, feeding preferences, and potential role as a malaria vector.
    METHODS: Mosquitoes were collected in July and August 2019 by CDC light traps in Nchelenge District in indoor sitting rooms, outdoor gathering spaces, and animal pens from 16:00-22:00. Host detection by PCR, COI and ITS2 PCR, and circumsporozoite (CSP) ELISA were performed on all samples morphologically identified as An. gibbinsi, and a subset of specimens were selected for COI and ITS2 sequencing. To determine risk factors for increased abundance of An. gibbinsi, a negative binomial generalized linear mixed-effects model was performed with household-level variables of interest.
    RESULTS: Comparison of COI and ITS2 An. gibbinsi reference sequences to the NCBI database revealed > 99% identity to "Anopheles sp. 6" from Kenya. More than 97% of specimens were morphologically and molecularly consistent with An. gibbinsi. Specimens were primarily collected in animal pen traps (59.2%), followed by traps outdoors near where humans gather (24.3%), and traps set indoors (16.5%). Host DNA detection revealed a high propensity for goats, but 5% of specimens with detected host DNA had fed on humans. No specimens were positive for Plasmodium falciparum sporozoites. Animal pens and inland households > 3 km from Lake Mweru were both associated with increased An. gibbinsi abundance.
    CONCLUSIONS: This is the first report of An. gibbinsi in Nchelenge District, Zambia. This study provided a species identity for unknown "An. sp. 6" in the NCBI database, which has been implicated in malaria transmission in Kenya. Composite data suggest that this species is largely zoophilic and exophilic, but comes into contact with humans and the malaria parasites they carry. This species should continue to be monitored in Zambia and neighbouring countries as a potential malaria vector.
    Keywords:  Anopheles gibbinsi; Anopheles species 6; ICEMR; Malaria; Vectors; Zambia
    DOI:  https://doi.org/10.1186/s12936-022-04231-5
  6. PLoS Negl Trop Dis. 2022 Jul 06. 16(7): e0010549
    City puzzles: Does urban land scape affect genetic population structure in Aedes aegypti?
    Lucía Maffey, Viviana Confalonieri, Esteban Hasson, Nicolás Schweigmann.
      Cities usually offer a suitable environment for the dengue vector Aedes aegypti, providing oviposition sites, accessibility to human hosts and nectar meals. However, large urban centres are highly heterogeneous environments, forming a patched landscape that could affect Ae. aegypti population dynamics and dispersal. Here, we performed a genome-wide analysis using Rad-seq data from 99 Ae. aegypti specimens collected in three areas within Buenos Aires city with varying levels of urbanization/land use: highly urbanized Area 1, intermediate Area 2 and poorly urbanized Area 3. We found an inverse association between urbanization levels and spatial genetic structure. Populations from highly urbanized Area 1 did not present genetic structure whereas two and three clusters were detected in Areas 2 and 3, respectively. In the case of Area 3, initial analyses showed separation in clusters was mostly due to elevated consanguinity within sites although three clusters were still detected after closely related individuals were discarded. Mosquitoes around each site displayed a high degree of isolation, evidencing a close dependence between the vector and human dwellings. Interestingly, specimens from distant boroughs (within the limits of the city) and the city's outskirts formed a single cluster with inner city sites (Area 1), highlighting the role of passive transport in shaping population structure. Genetic distances were poorly correlated with geographic distances in Buenos Aires, suggesting a stronger influence of passive than active dispersal on population structure. Only Area 2 displayed a significant isolation-by-distance pattern (p = 0.046), with males dispersing more than females (p = 0.004 and p = 0.016, respectively). Kinship analyses allowed us to detect full-siblings located 1.5 km apart in Area 1, which could be due to an extreme event of active female dispersal. Effective population size was higher in Area 2 confirming that cemeteries represent highly favourable environments for Ae. aegypti and need to be specifically targeted. Our results suggest that control programs should take into account urban landscape heterogeneity in order to improve vector control.
    DOI:  https://doi.org/10.1371/journal.pntd.0010549
  7. Malar J. 2022 Jul 02. 21(1): 210
    Evaluation of the residual efficacy and physical durability of five long-lasting insecticidal nets (LLINs) in Senegal.
    El Hadji Diouf, Mbaye Diouf, Constentin Dieme, Isabel Swamidoss, El Hadji Malick Ngom, Massila Wagué Senghor, Modou Mbaye, Abdoulaye Konaté, Youssouph Coulibaly, Dome Tine, Ibrahima Dia, Ellen Marie Dotson, Ousmane Faye, Lassana Konaté.
       BACKGROUND: The preventive and curative strategies of malaria are based on promoting the use of long-lasting insecticidal nets (LLINs) and treating confirmed cases with artemisinin-based combination therapy. These strategies have led to a sharp decline in the burden of malaria, which remains a significant public health problem in sub-Saharan countries. The objective of this study was to determine and compare the residual efficacy of LLINs recommended by the World Health Organization.
    METHODS: The study was conducted in six villages in two sites in Senegal located in the Sahelo-Sudanian area of the Thiès region, 70 km from Dakar and in Mbagame, a semi-urban zone in the Senegal River Valley. A census was conducted of all sleeping places in each household to be covered by LLINs. Five brands of LLIN were distributed, and every six months, retention rates, net use, maintenance, physical integrity, insecticide chemical content, and biological efficacy were examined for each type of LLIN.
    RESULTS: A total of 3012 LLINs were distributed in 1249 households in both sites, with an average coverage rate of 94% (95% CI 92.68-95.3). After 36 months, the average retention rate was 12.5% and this rate was respectively 20.5%, 15.1%, 10%, 7%, and 3% for Olyset Net®, Dawa Plus® 2.0, PermaNet® 2.0, NetProtect® and Life Net®, respectively. The proportion of LLINs with holes and the average number of holes per mosquito net increased significantly during each follow-up, with a large predominance of size 1 (small) holes for all types of LLINs distributed. During the three-year follow-up, bioassay mortality rates of a susceptible strain of insectary reared Anopheles coluzzii decreased in the following net types: in Dawa Plus® 2.0 (100% to 51.7%), PermaNet® 2.0 (96.6% to 83%), and Olyset Net® (96.6% to 33.3%). Mortality rates remained at 100% in Life Net® over the same time period. After 36 months, the average insecticide content per brand of LLIN decreased by 40.9% for Dawa Plus® 2.0, 31% for PermaNet® 2.0, 39.6% for NetProtect® and 51.9% for Olyset Net® and 40.1% for Life Net.
    CONCLUSIONS: Although some net types retained sufficient insecticidal activity, based on all durability parameters measured, none of the net types survived longer than 2 years.
    Keywords:  Durability; LLINs; Residual biological efficacy; Retention; Senegal
    DOI:  https://doi.org/10.1186/s12936-022-04230-6
  8. J Parasitol Res. 2022 ;2022 5665660
    Malaria Prevalence and Distribution of Plasmodium Species in Southern Region of Ethiopia.
    Anmut Assemie.
      Malaria is caused by Plasmodium species and transmitted by Anopheles mosquitoes, which is the most common medical concern all over the world, including in Ethiopia. The current systematic review's goal was to determine the overall malaria prevalence and Plasmodium species distribution in Ethiopia's southern area. To achieve these objectives, 716 articles were manually searched from online databases such as PubMed, Scopus, Google Scholar, Science Direct, and Web of Science. The pooled metalogistic regression was calculated with the STATA 16 software to present the pooled prevalence with a 95% confidence interval (CI). Eighteen full-text articles met the inclusion criteria and were included in the study, out of the 716 studies initially identified. The majority of the articles in the systematic review used a cross-sectional study design, with sample sizes ranging from 160 to 583,668 participants. The study's lowest and highest malaria prevalence was 0.93% and 82.84%, respectively. During the current systematic review, the estimated malaria prevalence was 19.19% (95% CI: 14.67-23.70). There were 263,476 positive individuals in the study, accounting for 148,734, 106,946, and 7,796 cases of P. falciparum, P. vivax, and mixed infections, respectively. The overall prevalence of P. falciparum and P. vivax was 8.97% (95% CI: 6.31, 11.63) and 7.94% (95% CI: 6.56, 9.33), respectively. According to the systematic review, the most predominant Plasmodium species responsible for malaria disease in the study area was P. falciparum. The highest malaria rates were found in this systematic review. In the systematic review, P. falciparum was the most dominant Plasmodium species that was responsible for malaria disease in the study area. This systematic review indicates the highest malaria prevalence in the southern regions of Ethiopia. Therefore, existing malaria prevention and control strategies in the southern region of Ethiopia should be revised.
    DOI:  https://doi.org/10.1155/2022/5665660
  9. Malar J. 2022 Jul 02. 21(1): 209
    Accelerating malaria elimination in Cambodia: an intensified approach for targeting at-risk populations.
    Siv Sovannaroth, Pengby Ngor, Vichka Khy, Julia C Dunn, Michelle K Burbach, Sovann Peng, Sarath Mak, Krung Siv, Giulia Manzoni, Jean Olivier Guintran, Luciano Tuseo, Rekol Huy.
       BACKGROUND: Malaria in Cambodia has decreased by 90.8% between 2010 and 2020, driven by the commitment of the National Center for Parasitology, Entomology and Malaria (CNM) and the achievements of the roll-out of a village malaria worker programme. However, in the first seven months of 2018, CNM identified a 207% increase (11,969 to 36,778) in confirmed malaria cases compared to the same months in the previous year. To address this increase, CNM developed the "Intensification Plan" (IP), implemented between October 2018 and December 2020.
    METHODS: The structure of the IP was summarized, including the selection of sites, the interventions implemented in the selected health facility catchment areas (HFCAs) and the monitoring and evaluation process. Data on IP interventions were collected by CNM and civil society organisations. Data on malaria cases and tests from all HFCAs in Cambodia from January 2018 to December 2020 were sourced from the Cambodia Malaria Information System (MIS) and WHO Malaria Elimination Database. Malaria data from IP HFCAs and non-IP HFCAs was analysed and compared to present the changes in malaria testing and confirmed cases before and during implementation of the IP.
    RESULTS: Between October 2018 and December 2020, through the IP 16,902 forest packs and 293,090 long-lasting insecticide treated nets were distributed. In the 45 HFCAs included in the IP, 431,143 malaria tests were performed and 29,819 malaria cases were diagnosed, 5364 (18%) of which were Plasmodium falciparum/mixed cases. During the intervention period, over all HFCAs included in IP, P. falciparum/mixed cases declined from 1029 to 39, a 96.2% decrease, and from 25.4 P. falciparum/mixed cases per HFCA to 0.9. HFCAs not included in IP declined from 468 to 43 cases, a 90.8% decrease, showing that routine malaria activities in Cambodia were also playing an important contribution to malaria control.
    CONCLUSIONS: Over the course of IP implementation there was a substantial increase in malaria testing and both overall malaria cases and P. falciparum/mixed cases decreased month on month. The initiative yields lessons learned for Cambodia to reach the final stage of elimination as well as for other countries aiming to accelerate their malaria control programmes.
    DOI:  https://doi.org/10.1186/s12936-022-04234-2
  10. Pan Afr Med J. 2022 ;41 275
    Status of malaria and its implications for elimination in an endemic province of South Africa: retrospective analysis.
    Joyce Mahlako Tsoka-Gwegweni.
      South Africa set a target to eliminate malaria by 2018. Kwa-Zulu-Natal (KZN) province was earmarked to reach the elimination goal first. However, recent evidence suggests that the province has not yet achieved the elimination goal. This study set out to assess the status of malaria in KZN province of South Africa and its implications for elimination. Using retrospective analysis, the study quantified and described 5 787 cases of malaria for the years 2010-2019 in KZN province of South Africa. Data on reported malaria cases were obtained from the Malaria Information System of the KZN Provincial Department of Health. More than 65% of the cases came from male patients aged 16 years and above. A high number of cases were reported in the years 2014, 2017 and 2018. More than 40% of the cases were imported from countries outside of South Africa. The study confirms an increase in malaria cases, especially during the elimination year. The imported malaria cases and other related factors pose a threat to achieving the elimination goal. The KZN province needs to strengthen elimination efforts, including strategies to prevent imported malaria cases to achieve the new elimination goal.
    Keywords:  KwaZulu-Natal; South Africa; elimination; malaria
    DOI:  https://doi.org/10.11604/pamj.2022.41.275.26774
  11. PLoS Negl Trop Dis. 2022 Jul 08. 16(7): e0010564
    An ecological niche model to predict the geographic distribution of Haemagogus janthinomys, Dyar, 1921 a yellow fever and Mayaro virus vector, in South America.
    Michael Celone, David Brooks Pecor, Alexander Potter, Alec Richardson, James Dunford, Simon Pollett.
      Yellow fever virus (YFV) has a long history of impacting human health in South America. Mayaro virus (MAYV) is an emerging arbovirus of public health concern in the Neotropics and its full impact is yet unknown. Both YFV and MAYV are primarily maintained via a sylvatic transmission cycle but can be opportunistically transmitted to humans by the bites of infected forest dwelling Haemagogus janthinomys Dyar, 1921. To better understand the potential risk of YFV and MAYV transmission to humans, a more detailed understanding of this vector species' distribution is critical. This study compiled a comprehensive database of 177 unique Hg. janthinomys collection sites retrieved from the published literature, digitized museum specimens and publicly accessible mosquito surveillance data. Covariate analysis was performed to optimize a selection of environmental (topographic and bioclimatic) variables associated with predicting habitat suitability, and species distributions modelled across South America using a maximum entropy (MaxEnt) approach. Our results indicate that suitable habitat for Hg. janthinomys can be found across forested regions of South America including the Atlantic forests and interior Amazon.
    DOI:  https://doi.org/10.1371/journal.pntd.0010564
  12. Sci Rep. 2022 Jul 07. 12(1): 11537
    The influence of the environment and indoor residual spraying on malaria risk in a cohort of children in Uganda.
    Margaux L Sadoine, Audrey Smargiassi, Ying Liu, Philippe Gachon, Guillaume Dueymes, Grant Dorsey, Michel Fournier, Joaniter I Nankabirwa, John Rek, Kate Zinszer.
      Studies have estimated the impact of the environment on malaria incidence although few have explored the differential impact due to malaria control interventions. Therefore, the objective of the study was to evaluate the effect of indoor residual spraying (IRS) on the relationship between malaria and environment (i.e. rainfall, temperatures, humidity, and vegetation) using data from a dynamic cohort of children from three sub-counties in Uganda. Environmental variables were extracted from remote sensing sources and averaged over different time periods. General linear mixed models were constructed for each sub-counties based on a log-binomial distribution. The influence of IRS was analysed by comparing marginal effects of environment in models adjusted and unadjusted for IRS. Great regional variability in the shape (linear and non-linear), direction, and magnitude of environmental associations with malaria risk were observed between sub-counties. IRS was significantly associated with malaria risk reduction (risk ratios vary from RR = 0.03, CI 95% [0.03-0.08] to RR = 0.35, CI95% [0.28-0.42]). Model adjustment for this intervention changed the magnitude and/or direction of environment-malaria associations, suggesting an interaction effect. This study evaluated the potential influence of IRS in the malaria-environment association and highlighted the necessity to control for interventions when they are performed to properly estimate the environmental influence on malaria. Local models are more informative to guide intervention program compared to national models.
    DOI:  https://doi.org/10.1038/s41598-022-15654-0
  13. Int J Environ Res Public Health. 2022 Jul 04. pii: 8182. [Epub ahead of print]19(13):
    Seroprevalence Rates against West Nile, Usutu, and Tick-Borne Encephalitis Viruses in Blood-Donors from North-Western Romania.
    Mircea Coroian, Andrei Daniel Mihalca, Gerhard Dobler, Kathrin Euringer, Philipp Girl, Silvia-Diana Borșan, Zsuzsa Kalmár, Violeta Tincuța Briciu, Mirela Flonta, Adriana Topan, Amanda Lelia Rădulescu, Andrei Ungur, Mihaela Sorina Lupșe.
       INTRODUCTION: West Nile virus (WNV), Usutu virus (USUV), and the tick-borne encephalitis virus (TBEV) are all arboviruses belonging to Flaviviridae family. All are characterized by vectorial transmission and sometimes associated with neuroinvasive infections. The circulation of these viruses is considered endemic in parts of Europe, with human cases reported in many countries. Among hosts, the viruses are vectored by hematophagous arthropods, such as mosquitoes (WNV, USUV) and ticks (TBEV). Considering the currently outdated knowledge regarding the epidemiology of these viruses in Romania, the aim of our study was to assess the seroprevalence rates of WNV, USUV, and TBEV among healthy blood donors in north-western Romania.
    METHODS: Human blood samples from healthy donors were collected between November 2019 and February 2020 in six counties from the north-western region of Romania. The samples were serologically tested by ELISA and serum neutralization test.
    RESULTS: Overall, we obtained a seroprevalence of 3.17% for WNV, 0.08% for TBEV, and 0% for USUV.
    CONCLUSION: Despite the low seroprevalence of WNV, USUV, and TBEV in our study, we highlight the need for continuous nationwide vector and disease surveillance and implementation of control measures. Further research is required for an optimal overview of the epidemiological status of the Romanian population regarding these flaviviruses together with countrywide awareness campaigns.
    Keywords:  Usutu virus; West Nile virus; arboviruses; public health; tick-borne encephalitis virus; vector-borne diseases
    DOI:  https://doi.org/10.3390/ijerph19138182
  14. Int J Infect Dis. 2022 Jul 03. pii: S1201-9712(22)00383-6. [Epub ahead of print]
    Epidemiology and costs of dengue in Brazil: a systematic literature review.
    João Bosco Siqueira Junior, Eduardo Massad, Abner Lobao-Neto, Randee Kastner, Louisa Oliver, Elaine Gallagher.
       BACKGROUND: Dengue infection is a growing public health problem, with the number of reported cases increasing in the Americas and Worldwide. This review characterizes the epidemiological and cost burden of dengue in Brazil.
    METHODS: Embase, MEDLINE, Evidence Based Reviews databases and grey literature sources were searched for published literature and surveillance reports on epidemiology (between 2000-2019) and costs (between 2009-2019) of dengue in Brazil. Studies were included if they reported data on incidence, seroprevalence, serotype distribution, expansion factors, hospitalisation, mortality, or costs. Data were summarized descriptively and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.
    RESULTS: A total of 344 publications were included (167 peer-reviewed and 177 grey literature). Dengue outbreaks increased in incidence and frequency, with the highest incidence observed in 2015 at 807 cases per 100,000 population. Outbreaks were related to alternating predominant serotypes. Dengue was more frequent in young adults (20-39) and in the Midwest. Cost and societal impacts are substantial and varied across regions, age and public/private delivery of healthcare services.
    CONCLUSIONS: The burden of dengue in Brazil is increasing and likely underestimated. Therefore, it is important to develop and implement new strategies, including vaccination, to reduce the disease burden.
    Keywords:  Brazil; dengue; economic impact; epidemiology; incidence; serotype
    DOI:  https://doi.org/10.1016/j.ijid.2022.06.050
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