bims-mosdis Biomed News
on Mosquito distribution and disease
Issue of 2023–06–04
eleven papers selected by
Richard Halfpenny, Staffordshire University
  1. Entomological surveillance of invasive Aedes mosquitoes in Mazandaran Province, northern Iran from 2014 to 2020.
  2. Risk of dengue, Zika, and chikungunya transmission in the metropolitan area of Cucuta, Colombia: cross-sectional analysis, baseline for a cluster-randomised controlled trial of a novel vector tool for water containers.
  3. Characterizing seasonal changes in the reproductive activity of Culex mosquitoes throughout the fall, winter, and spring in Ohio.
  4. Distribution of Aedes (Stegomyia) cretinus in Türkiye
  5. An economic evaluation of Wolbachia deployments for dengue control in Vietnam.
  6. Natural vectors of Plasmodium knowlesi and other primate, avian and ungulate malaria parasites in Narathiwat Province, Southern Thailand.
  7. Vertical dispersal of Aedes albopictus within multi-story buildings in downtown Shanghai, China.
  8. Spatiotemporal and meteorological relationships in dengue transmission in the Dominican Republic, 2015-2019.
  9. Prevalence of dengue virus in Haripur district, Khyber Pakhtunkhwa, Pakistan.
  10. Effects of migration rates and vaccination on the spread of yellow fever in Latin American communities.
  11. No evidence of sustained nonzoonotic Plasmodium knowlesi transmission in Malaysia from modelling malaria case data.
  1. Sci Rep. 2023 05 29. 13(1): 8683
    Entomological surveillance of invasive Aedes mosquitoes in Mazandaran Province, northern Iran from 2014 to 2020.
    Seyed Hassan Nikookar, Ali Charkame, Asghar Nezammahalleh, Eslam Moradi-Asl, Ahmadali Enayati, Mahmoud Fazeli-Dinan, Mohammad Mehdi Sedaghat, Morteza Zaim.
      Mosquitoes are the most important vectors of serious infectious diseases in the world. Dengue, Zika, chikungunya and yellow fever are emerging and re-emerging infectious diseases, associated with the distribution of two key vectors i.e. Aedes aegypti and Aedes albopictus throughout the world including countries neighbouring Iran. Entomological surveillance was planned and performed monthly from May to December during 2014-2020 in selected counties of Mazandaran Province, North of Iran, by ovitrap, larval collection, hand catch and human baited trap. Overall, 4410 Aedes specimens including 2376 larvae (53.9%) and 2034 (46.1%) adults belonging to six species, namely Aedes vexans, Aedes geniculatus, Aedes caspius, Aedes echinus, Aedes pulcritarsis and Aedes flavescence were collected and morphologically identified. Over the seven years of surveillance, Ae. aegypti and Ae. albopictus were not found by any sampling method. Aedes vexans and Ae. geniculatus were the most abundant species, their populations peaked in October and November and was positively correlated with precipitation and relative humidity. Aedes flavescence was a new species record for the province. A flowchart for planning and implementation of invasive mosquito surveillance for provincial health authorities in the country is proposed. These surveillance efforts provide basic and timely information for the health system to act promptly on integrated and intensified surveillance and control programs should Ae. aegypti and Ae. albopictus detected in the province.
    DOI:  https://doi.org/10.1038/s41598-023-35860-8
  2. BMC Public Health. 2023 05 30. 23(1): 1000
    Risk of dengue, Zika, and chikungunya transmission in the metropolitan area of Cucuta, Colombia: cross-sectional analysis, baseline for a cluster-randomised controlled trial of a novel vector tool for water containers.
    Maria Angelica Carrillo, Rocio Cardenas, Johanna Yañez, Max Petzold, Axel Kroeger.
       BACKGROUND: Arbovirus diseases such as dengue, Zika, and chikungunya are a public health threat in tropical and subtropical areas. In the absence of a vaccine or specific treatment, vector management (in this case the control of the primary vector Aedes aegypti) is the best practice to prevent the three diseases. A good understanding of vector behaviour, ecology, human mobility and water use can help design effective vector control programmes. This study collected baseline information on these factors for identifying the arbovirus transmission risk and assessed the requirements for a large intervention trial in Colombia.
    METHODS: Baseline surveys were conducted in 5,997 households, randomly selected from 24 clusters (neighbourhoods with on average 2000 houses and 250 households inspected) in the metropolitan area of Cucuta, Colombia. The study established population characteristics including water management and mobility as well as larval-pupal indices which were estimated and compared in all clusters. Additionally, the study estimated disease incidence from two sources: self-reported dengue cases in the household survey and cases notified by the national surveillance system.
    RESULTS: In all 24 study clusters similar social and demographic characteristics were found but the entomological indicators and estimated disease incidence rates varied. The entomological indicators showed a high vector infestation: House Index = 25.1%, Container Index = 12.3% and Breteau Index = 29.6. Pupae per person Index (PPI) as an indicator of the transmission risk showed a large range from 0.22 to 2.04 indicating a high transmission risk in most clusters. The concrete ground tanks for laundry -mostly outdoors and uncovered- were the containers with the highest production of Ae. aegypti as 86.3% of all 17,613 pupae were identified in these containers. Also, the annual incidence of dengue was high: 841.6 self-reported cases per 100,000 inhabitants and the dengue incidence notified by the National surveillance system was 1,013.4 cases per 100,000 in 2019. Only 2.2% of the households used container water for drinking. 40.3% of the study population travelled during the day (when Aedes mosquitoes bite) outside their clusters.
    CONCLUSIONS: The production of Ae. aegypti mosquitoes occurred almost exclusively in concrete ground tanks for laundry (lavadero), the primary intervention target. The baseline study provides necessary evidence for the design and implementation of a cluster randomized intervention trial in Colombia.
    Keywords:  Aedes aegypti; Chikungunya; Dengue; Zika
    DOI:  https://doi.org/10.1186/s12889-023-15893-4
  3. Parasit Vectors. 2023 May 31. 16(1): 173
    Characterizing seasonal changes in the reproductive activity of Culex mosquitoes throughout the fall, winter, and spring in Ohio.
    Alden Siperstein, Laura W Pomeroy, Sydney Robare, Lucas Sarko, Hannah Dehus, Taylor Lowmiller, Lydia Fyie, Megan E Meuti.
       BACKGROUND: Culex mosquitoes are the primary vectors of West Nile virus (WNV) across the USA. Understanding when these vectors are active indicates times when WNV transmission can occur. This study determined the proportion of female Culex mosquitoes that were in diapause during the fall and winter and when they terminated diapause and began blood feeding in the spring.
    METHODS: Mosquitoes were collected from parks using various traps and/or aspirated from culverts in Franklin County, Ohio, from October to mid-May from 2019 to 2022. Culex mosquitoes were morphologically identified to species, and the ovaries of females were dissected to determine their diapause and parity statuses.
    RESULTS: By early October 2021, roughly 95% of Culex pipiens collected in culverts were in diapause and 98% of Cx. erraticus were in diapause. Furthermore, gravid and blood-fed Culex salinarius, Cx. pipiens, and Cx. restuans were collected in late November in 2019 and 2021 in standard mosquito traps. In the winter of 2021, the proportions of non-diapausing Culex decreased within culverts. The last non-diapausing Cx. erraticus was collected in late December 2021 while the final non-diapausing Cx. pipiens was collected in mid-January 2022, both in culverts. Roughly 50% of Cx. pipiens terminated diapause by mid-March 2022, further supported by our collections of gravid females in late March in all 3 years of mosquito collection. In fact, male mosquitoes of Cx. pipiens, Cx. restuans, and Cx. territans were collected by the 1st week of May in 2022, indicating that multiple species of Culex produced a second generation that reached adulthood by this time.
    CONCLUSIONS: We collected blood-fed and gravid Culex females into late November in 2 of the 3 years of our collections, indicating that it might be possible for WNV transmission to occur in late fall in temperate climates like Ohio. The persistence of non-diapausing Cx. pipiens and Cx. erraticus throughout December has important implications for the winter survival of WNV vectors and our overall understanding of diapause. Finally, determining when Culex terminate diapause in the spring may allow us to optimize mosquito management programs and reduce the spread of WNV before it is transmitted to humans.
    Keywords:  Culex erraticus; Culex pipiens; Culex restuans; Culvert; Diapause; Overwintering; Seasonality; West Nile virus
    DOI:  https://doi.org/10.1186/s13071-023-05806-0
  4. Turkiye Parazitol Derg. 2023 06 29. 47(2): 117-123
    Distribution of Aedes (Stegomyia) cretinus in Türkiye
    Fatih Mehmet Şimşek, Sare İlknur Yavaşoğlu.
       OBJECTIVE: Aedes cretinus, a white and black stripped Aedes species, shares morphological similarities with Aedes albopictus and Aedes aegypti which are among the most important vectors and invasive species in the world. Due to its limited distribution and low population density, information on the biology and ecology of the species has been limited so far. This study aimed to determine distribution of Ae. cretinus in Türkiye.
    METHODS: Field works have been carried out in the Mediterranean, Aegean and Marmara Regions of Türkiye. Larval samples were collected by larval dippers while adult mosquito catches were performed using the human landing catch method and CDC-light traps.
    RESULTS: A total of 44 different Ae. cretinus populations were identified in the Mediterranean, Aegean and Marmara Regions of Türkiye. The larval specimen collected from small containers, tires, tree holes and natural small habitats. A plane (Platanus orientalis), walnut (Juglans regia), Türkiye oak (Quercus cerris), chestnut (Castenea sativa) and cedar (Cedrus libani) tree holes are the main larval habitats in which the specimen collected. In some localities, larvae were found together with Anopheles plumbeus, Anopheles claviger and Aedes geniculatus larvae in tree holes. Human landing catch method captured a greater number of females than CDC-light traps.
    CONCLUSION: This study determined the distribution of Ae. cretinus in Türkiye for the first time. Information on respective geographic distribution of Ae. cretinus is fundamental for effective control programmes. Further studies are needed to understand the biology and ecology of these species.
    Keywords:  Aedes cretinus; Mediterranean; distribution; Aegean; Marmara
    DOI:  https://doi.org/10.4274/tpd.galenos.2023.72692
  5. PLoS Negl Trop Dis. 2023 May 30. 17(5): e0011356
    An economic evaluation of Wolbachia deployments for dengue control in Vietnam.
    Hugo C Turner, Duong Le Quyen, Reynold Dias, Phan Thi Huong, Cameron P Simmons, Katherine L Anders.
       INTRODUCTION: Dengue is a major public health challenge and a growing problem due to climate change. The release of Aedes aegypti mosquitoes infected with the intracellular bacterium Wolbachia is a novel form of vector control against dengue. However, there remains a need to evaluate the benefits of such an intervention at a large scale. In this paper, we evaluate the potential economic impact and cost-effectiveness of scaled Wolbachia deployments as a form of dengue control in Vietnam-targeted at the highest burden urban areas.
    METHODS: Ten settings within Vietnam were identified as priority locations for potential future Wolbachia deployments (using a population replacement strategy). The effectiveness of Wolbachia deployments in reducing the incidence of symptomatic dengue cases was assumed to be 75%. We assumed that the intervention would maintain this effectiveness for at least 20 years (but tested this assumption in the sensitivity analysis). A cost-utility analysis and cost-benefit analysis were conducted.
    RESULTS: From the health sector perspective, the Wolbachia intervention was projected to cost US$420 per disability-adjusted life year (DALY) averted. From the societal perspective, the overall cost-effectiveness ratio was negative, i.e. the economic benefits outweighed the costs. These results are contingent on the long-term effectiveness of Wolbachia releases being sustained for 20 years. However, the intervention was still classed as cost-effective across the majority of the settings when assuming only 10 years of benefits.
    CONCLUSION: Overall, we found that targeting high burden cities with Wolbachia deployments would be a cost-effective intervention in Vietnam and generate notable broader benefits besides health gains.
    DOI:  https://doi.org/10.1371/journal.pntd.0011356
  6. Sci Rep. 2023 Jun 01. 13(1): 8875
    Natural vectors of Plasmodium knowlesi and other primate, avian and ungulate malaria parasites in Narathiwat Province, Southern Thailand.
    Surasuk Yanmanee, Sunee Seethamchai, Napaporn Kuamsab, Sunate Karaphan, Wannapa Suwonkerd, Somchai Jongwutiwes, Chaturong Putaporntip.
      To date, four species of simian malaria parasites including Plasmodium knowlesi, P. cynomolgi, P. inui and P. fieldi have been incriminated in human infections in Thailand. Although the prevalence of malaria in macaque natural hosts has been investigated, their vectors remain unknown in this country. Herein, we performed a survey of Anopheles mosquitoes during rainy and dry seasons in Narathiwat Province, Southern Thailand. Altogether 367 Anopheles mosquitoes were captured for 40 nights during 18:00 to 06:00 h by using human-landing catches. Based on morphological and molecular identification, species composition comprised An. maculatus (37.06%), An. barbirostris s.l. (31.34%), An. latens (17.71%), An. introlatus (10.08%) and others (3.81%) including An. umbrosus s.l., An. minimus, An. hyrcanus s.l., An. aconitus, An. macarthuri and An. kochi. Analyses of individual mosquitoes by PCR, sequencing and phylogenetic inference of the mitochondrial cytochrome genes of both malaria parasites and mosquitoes have revealed that the salivary gland samples of An. latens harbored P. knowlesi (n = 1), P. inui (n = 2), P. fieldi (n = 1), P. coatneyi (n = 1), P. hylobati (n = 1) and an unnamed Plasmodium species known to infect both long-tailed and pig-tailed macaques (n = 2). The salivary glands of An. introlatus possessed P. cynomolgi (n = 1), P. inui (n = 1), P. hylobati (n = 1) and coexistence of P. knowlesi and P. inui (n = 1). An avian malaria parasite P. juxtanucleare has been identified in the salivary gland sample of An. latens. Three other distinct lineages of Plasmodium with phylogenetic affinity to avian malaria species were detected in An. latens, An. introlatus and An. macarthuri. Interestingly, the salivary gland sample of An. maculatus contained P. caprae, an ungulate malaria parasite known to infect domestic goats. Most infected mosquitoes harbored multiclonal Plasmodium infections. All Plasmodium-infected mosquitoes were captured during the first quarter of the night and predominantly occurred during rainy season. Since simian malaria in humans has a wide geographic distribution in Thailand, further studies in other endemic areas of the country are mandatory for understanding transmission and prevention of zoonotic malaria.
    DOI:  https://doi.org/10.1038/s41598-023-36017-3
  7. Parasit Vectors. 2023 Jun 01. 16(1): 176
    Vertical dispersal of Aedes albopictus within multi-story buildings in downtown Shanghai, China.
    Shuqing Jin, Jian Fan, Hui Cao, Zhendong Zhang, Peien Leng, Qiang Gao.
       BACKGROUND: Shanghai has numerous high-rise apartment and office buildings, but the effects of these high-rise spaces on the vertical dispersal, oviposition and blood feeding behavior of Aedes albopictus are unknown.
    METHODS: In six multi-story building blocks in downtown Shanghai, 174 mosq-ovitraps (MOT) were placed both indoors and outdoors for Ae. albopictus collection at different vertical heights from the 1st to 6th floors and a terrace on the 8th floor. Collections were made for 4 months. The human landing catch (HLC) method for Ae. albopictus monitoring was also conducted on 6 consecutive days on six floors of two of the six buildings to study the feeding behavior of Ae. albopictus at different heights.
    RESULTS: Both MOTs and HLCs collected Ae. albopictus at all monitored heights. The vertical distribution, oviposition pattern and biting behavior varied significantly among the seven heights (1st-6th floors and 8th floor) (mosq-ovitrap index (MOI): X2 = 140.616, df = 6, P < 0.001; HLC: F (5, 138) = 15.111, P < 0.001). The MOI at low heights (1st + 2nd floors) was significantly higher than that at medium (3rd + 4th floor, P < 0.001) and high heights (5th + 6th floors, P < 0.001), and there was no significant difference in the MOI for the 3rd-6th floors. The outdoor MOIs were significantly higher than indoor MOIs at all heights (outdoor 23.09% vs. indoor 9.58%, X2 = 74.121, df = 1, P < 0.001). Aedes albopictus HLC density on the ground floor was significantly higher than that on all other heights (5.04 vs. 0.13, 0.29, 0.58, 0.79 and 1.50 per half hour, P < 0.05), while no difference was detected among the heights above the ground floor (P > 0.05).
    CONCLUSIONS: Aedes albopictus is more common near the ground level, but it can easily disperse to higher floors in the multi-story buildings of urban Shanghai. No significant differences in Ae. albopictus density were detected within the 3rd-6th floors using MOT or HLC. This suggests that Ae. albopictus might also disperse to areas above the 6th floor and seek hosts there. Aedes albopictus prefers to oviposit outdoors; however, Ae. albopictus was also able to inhabit, oviposit and engage in blood-feeding behavior indoors on different floors. The three-dimensional dispersal pattern of Ae. albopictus in urban areas could facilitate arbovirus transmission and increase the difficulty of dengue control.
    Keywords:  Aedes albopictus; Downtown Shanghai; Human landing catch; Mosq-ovitrap; Multi-story building; Vertical dispersal
    DOI:  https://doi.org/10.1186/s13071-023-05732-1
  8. Trop Med Health. 2023 Jun 02. 51(1): 32
    Spatiotemporal and meteorological relationships in dengue transmission in the Dominican Republic, 2015-2019.
    Michael A Robert, Helena Sofia Rodrigues, Demian Herrera, Juan de Mata Donado Campos, Fernando Morilla, Javier Del Águila Mejía, María Elena Guardado, Ronald Skewes, Manuel Colomé-Hidalgo.
      Dengue has broadened its global distribution substantially in the past two decades, and many endemic areas are experiencing increases in incidence. The Dominican Republic recently experienced its two largest outbreaks to date with 16,836 reported cases in 2015 and 20,123 reported cases in 2019. With continued increases in dengue transmission, developing tools to better prepare healthcare systems and mosquito control agencies is of critical importance. Before such tools can be developed, however, we must first better understand potential drivers of dengue transmission. To that end, we focus in this paper on determining relationships between climate variables and dengue transmission with an emphasis on eight provinces and the capital city of the Dominican Republic in the period 2015-2019. We present summary statistics for dengue cases, temperature, precipitation, and relative humidity in this period, and we conduct an analysis of correlated lags between climate variables and dengue cases as well as correlated lags among dengue cases in each of the nine locations. We find that the southwestern province of Barahona had the largest dengue incidence in both 2015 and 2019. Among all climate variables considered, lags between relative humidity variables and dengue cases were the most frequently correlated. We found that most locations had significant correlations with cases in other locations at lags of zero weeks. These results can be used to improve predictive models of dengue transmission in the country.
    Keywords:  Correlation lags; Dengue; Dominican Republic; Spatial analysis
    DOI:  https://doi.org/10.1186/s41182-023-00517-9
  9. J Infect Public Health. 2023 Jul;pii: S1876-0341(23)00140-5. [Epub ahead of print]16(7): 1131-1136
    Prevalence of dengue virus in Haripur district, Khyber Pakhtunkhwa, Pakistan.
    Humera Qureshi, Muhammad Imran Khan, Suk Joo Bae, Sohail Akhtar, Aamer Ali Khattak, Ayesha Haider, Alisha Nisar.
      Dengue virus (DENV) has caused about 12 large outbreaks in Pakistan, resulting in 286,262 morbidities and 1108 deaths. The most affected province is Khyber Pakhtunkhwa (KP). This study was conducted to determine the average DENV prevalence in different areas of the Haripur endemic district of KP and the causing factors of DENV.
    METHODS: This work was a cross-sectional study that was performed in the DENV endemic district Haripur. A total of 761 individuals were included in this study. The data were categorized according to sex, age and symptoms (like fever, body aches, bleeding, and skin rash). For data analysis, SPSS 23 version was applied. ArcGIS version 10.8 was used to map the study area.
    RESULTS: In this study, there were 716 confirmed cases of DENV fever, including 421 males (58.8%) and 295 females (41.2%). The most affected age range, 16-30 years, reported by 301 (42.0%), was followed by 31-45 years, 184 (25.7%), above 46 years, 132 (18.4%), and 0-15 years, 99 (13.8%). The positive IgG cases were 581(81.0%). Those whose age ranges from 1 to 15 years 82 (8.7%) cases, 16-30 years 244 (34.1%), 31-45 years 156 (21.8%), above 46-year age 99 (13.8%) cases. In addition, this suggests that those between the ages of 16 and 30 are at the highest risk for DENV infection. However, this might be the fact that individuals in this age range are more likely to be out in the environment, making them more vulnerable to the virus.
    CONCLUSION: Over the past ten years, DENV fever has become increasingly prevalent in Pakistan. The risk is substantially higher for males. Dengue outbreaks hit those between the ages of 16 and 30 the hardest. The proper monitoring and assessment of DENV are necessary for prevention and controlling the disease. Disease surveillance includes identification and molecular characterization of infected persons and monitoring mosquito populations in high-risk locations for the purpose of vector surveillance. In order to assess the community's willingness to participate in DENV preventive efforts, behavioral impact surveillance is also necessary.
    Keywords:  DENV; Dengue virus; Kyber Pakhtunkhwa; Pakistan; Prevalence
    DOI:  https://doi.org/10.1016/j.jiph.2023.04.021
  10. Rev Panam Salud Publica. 2023 ;47 e86
    Effects of migration rates and vaccination on the spread of yellow fever in Latin American communities.
    Sabrina Simon, Marcos Amaku, Eduardo Massad.
       Objective: To assess how relevant the flow of people between communities is, compared to vaccination and type of vector, on the spread and potential outbreaks of yellow fever in a disease-free host community.
    Methods: Using a SEIRV-SEI model for humans and vectors, we applied numerical simulations to the scenarios: (1) migration from an endemic community to a disease-free host community, comparing the performance of Haemagogus janthinomys and Aedes aegypti as vectors; (2) migration through a transit community located on a migratory route, where the disease is endemic, to a disease-free one; and (3) effects of different vaccination rates in the host community, considering the vaccination of migrants upon arrival.
    Results: Results show no remarkable differences between scenarios 1 and 2. The type of vector and vaccination coverage in the host community are more relevant for the occurrence of outbreaks than migration rates, with H. janthinomys being more effective than A. aegypti.
    Conclusions: With vaccination being more determinant for a potential outbreak than migration rates, vaccinating migrants on arrival may be one of the most effective measures against yellow fever. Furthermore, H. janthinomys is a more competent vector than A. aegypti at similar densities, but the presence of A. aegypti is a warning to maintain vaccination above recommended levels.
    Keywords:  Latin America; Yellow fever; disease outbreaks; epidemiological models; human migration; public health; vaccination; vector borne diseases
    DOI:  https://doi.org/10.26633/RPSP.2023.86
  11. Nat Commun. 2023 Jun 01. 14(1): 2945
    No evidence of sustained nonzoonotic Plasmodium knowlesi transmission in Malaysia from modelling malaria case data.
    Kimberly M Fornace, Hillary M Topazian, Isobel Routledge, Syafie Asyraf, Jenarun Jelip, Kim A Lindblade, Mohammad Saffree Jeffree, Pablo Ruiz Cuenca, Samir Bhatt, Kamruddin Ahmed, Azra C Ghani, Chris Drakeley.
      Reported incidence of the zoonotic malaria Plasmodium knowlesi has markedly increased across Southeast Asia and threatens malaria elimination. Nonzoonotic transmission of P. knowlesi has been experimentally demonstrated, but it remains unknown whether nonzoonotic transmission is contributing to increases in P. knowlesi cases. Here, we adapt model-based inference methods to estimate RC, individual case reproductive numbers, for P. knowlesi, P. falciparum and P. vivax human cases in Malaysia from 2012-2020 (n = 32,635). Best fitting models for P. knowlesi showed subcritical transmission (RC < 1) consistent with a large reservoir of unobserved infection sources, indicating P. knowlesi remains a primarily zoonotic infection. In contrast, sustained transmission (RC > 1) was estimated historically for P. falciparum and P. vivax, with declines in RC estimates observed over time consistent with local elimination. Together, this suggests sustained nonzoonotic P. knowlesi transmission is highly unlikely and that new approaches are urgently needed to control spillover risks.
    DOI:  https://doi.org/10.1038/s41467-023-38476-8
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