Pyrethroid Susceptibility in Culex quinquefasciatus Say. (Diptera: Culicidae) Populations from Delta State, Niger-Delta Region, Nigeria

Author(s):  
Chioma C Ojianwuna ◽  
Ahmed I Omotayo ◽  
Victor N Enwemiwe ◽  
Fouad A Adetoro ◽  
Destiny N Eyeboka ◽  
...  

Abstract The development of insecticide resistance in different species of mosquitoes to Pyrethroids is a major challenge for vector-borne diseases transmitted by mosquitoes. Failure of Pyrethroids in control of mosquitoes would impact negatively on the gains recorded in control of mosquito-borne diseases in previous years. In anticipation of a country-wide deployment of Pyrethroid-treated nets for control of mosquito-borne diseases in Nigeria, this study assessed susceptibility of Culex quinquefasciatus Say. (Diptera: Culicidae) to Pyrethroids in Owhelogbo, Ejeme and Oria-Abraka communities in Delta State, Niger-Delta, Nigeria. Three to five day old Cx. quinquefasciatus were exposed to Deltamethrin (0.05%), Permethrin (0.75%), and Alphacypermethrin (0.05%) using World Health Organization bioassay method. Polymerase chain reaction (PCR) was employed in characterization of species and knockdown mutation. Results revealed that Cx. quinquefasciatus were generally susceptible (98-100%) to Deltamethrin, Permethrin, and Alphacypermethrin in the three communities with the exception of Owhelogbo where resistance to Deltamethrin (97%) was suspected. Knockdown time to Deltamethrin (11.51, 11.23, and 12.68 min), Permethrin (28.75, 13.26, and 14.49 min), and Alphacypermethrin (15.07, 12.50, and 13.03 min) were considerably low for Owhelogbo, Ejeme, and Oria-Abraka Cx. quinquefasciatus populations, respectively. Species identification result showed that all amplified samples were Cx. quinquefasciatus; however, no kdr allele was found in the three populations. Deployment of pyrethroid-treated nets for control of mosquito-borne diseases in Niger-Delta region of Nigeria is capable of reducing burden of diseases transmitted by Cx. quinquefasciatus as well as addressing nuisance value of the vector; however, caution must be entertained so as not to increase selection pressure thereby aiding resistance development.

Author(s):  
Mara Moreno-Gómez ◽  
Rubén Bueno-Marí ◽  
Andrea Drago ◽  
Miguel A Miranda

Abstract Vector-borne diseases are a worldwide threat to human health. Often, no vaccines or treatments exist. Thus, personal protection products play an essential role in limiting transmission. The World Health Organization (WHO) arm-in-cage (AIC) test is the most common method for evaluating the efficacy of topical repellents, but it remains unclear whether AIC testing conditions recreate the mosquito landing rates in the field. This study aimed to estimate the landing rate outdoors, in an area of Europe highly infested with the Asian tiger mosquito (Aedes albopictus (Skuse, 1894, Diptera: Culididae)), and to determine how to replicate this rate in the laboratory. To assess the landing rate in the field, 16 individuals were exposed to mosquitoes in a highly infested region of Italy. These field results were then compared to results obtained in the laboratory: 1) in a 30 m3 room where nine volunteers were exposed to different mosquito abundances (ranges: 15–20, 25–30, and 45–50) and 2) in a 0.064 m3 AIC test cage where 10 individuals exposed their arms to 200 mosquitoes (as per WHO requirements). The highest mosquito landing rate in the field was 26.8 landings/min. In the room test, a similar landing rate was achieved using 15–20 mosquitoes (density: 0.50–0.66 mosquitoes/m3) and an exposure time of 3 min. In the AIC test using 200 mosquitoes (density: 3,125 mosquitoes/m3), the landing rate was 229 ± 48 landings/min. This study provides useful reference values that can be employed to design new evaluation standards for topical repellents that better simulate field conditions.


Author(s):  
Kalé Kponee ◽  
Jamaji Nwanaji-Enwerem ◽  
Xianqiang Fu ◽  
Iyenemi Kakulu ◽  
Marc Weisskopf ◽  
...  

The implications of environmental contamination on human health in the Niger Delta region of Nigeria remain a topic of growing international public health interest. To better understand ongoing air pollution and initiate remediation efforts, the United Nations Environmental Programme (UNEP) report recommended the monitoring of volatile organic compounds (VOCs) across different media (water, soil, and air) in Ogoniland, an at-risk population in the Niger Delta region of Nigeria. In this pilot study, we measured indoor VOC concentrations in the indoor air of 20 households in Ogale, an Ogoniland community whose groundwater system is contaminated with benzene at levels 900 times the World Health Organization guidelines and evaluated self-reported health conditions and predicted cancer risks and hazards from inhalation exposure to VOCs. We detected higher concentrations of benzene (mean = 25.7 μg/m3, SD = 23.2 μg/m3) and naphthalene (mean = 7.6 μg/m3, SD = 13.8 μg/m3) than has been reported in other regions. Although study participants reported health symptoms consistent with VOC exposure, we were underpowered to detect a significant association between select indoor VOCs and these self-reported health symptoms using univariate logistic regression models. These findings suggest that that the health symptoms reported by participants may be poor proxies for the underlying disease processes associated with adverse health outcomes due to VOC exposure in this community and that the burden of adverse health effects due to VOC exposure may stem from the contaminated groundwater system. We estimated a non-cancer hazard quotient of 3 from exposure to naphthalene and lifetime excess cancer risks from exposure to naphthalene, benzene, p-dichlorobenzene, carbon tetrachloride, and ethylbenzene of 3 × 10−4, 2 × 10−4, 6 × 10−5, 6 × 10−6, and 1 × 10−5, respectively. These results exceed common risk benchmarks in the United States, suggesting a need for further studies to characterize VOC exposures, sources, and associated health risks in the Niger Delta.


Author(s):  
Emily Chan ◽  
Tiffany Sham ◽  
Tayyab Shahzada ◽  
Caroline Dubois ◽  
Zhe Huang ◽  
...  

Climate change is expanding the global at-risk population for vector-borne diseases (VBDs). The World Health Organization (WHO) health emergency and disaster risk management (health-EDRM) framework emphasises the importance of primary prevention of biological hazards and its value in protecting against VBDs. The framework encourages stakeholder coordination and information sharing, though there is still a need to reinforce prevention and recovery within disaster management. This keyword-search based narrative literature review searched databases PubMed, Google Scholar, Embase and Medline between January 2000 and May 2020, and identified 134 publications. In total, 10 health-EDRM primary prevention measures are summarised at three levels (personal, environmental and household). Enabling factor, limiting factors, co-benefits and strength of evidence were identified. Current studies on primary prevention measures for VBDs focus on health risk-reduction, with minimal evaluation of actual disease reduction. Although prevention against mosquito-borne diseases, notably malaria, has been well-studied, research on other vectors and VBDs remains limited. Other gaps included the limited evidence pertaining to prevention in resource-poor settings and the efficacy of alternatives, discrepancies amongst agencies’ recommendations, and limited studies on the impact of technological advancements and habitat change on VBD prevalence. Health-EDRM primary prevention measures for VBDs require high-priority research to facilitate multifaceted, multi-sectoral, coordinated responses that will enable effective risk mitigation.


Author(s):  
Antonio Ligsay ◽  
Olivier Telle ◽  
Richard Paul

Cities worldwide are facing ever-increasing pressure to develop mitigation strategies for all sectors to deal with the impacts of climate change. Cities are expected to house 70% of the world’s population by 2050 and developing related resilient health systems is a significant challenge. Because of their physical nature, cities’ surface temperatures are often substantially higher than that of the surrounding rural areas, generating the so-called Urban Heat Island (UHI) effect. Whilst considerable emphasis has been placed on strategies to mitigate against the UHI-associated negative health effects of heat and pollution, the World Health Organization estimates that one of the main consequences of global warming will be an increased burden of such vector-borne diseases. Many of the major mosquito-borne diseases are urban and thus the global population exposed to these pathogens will steadily increase. Mitigation strategies beneficial for one sector may, however, be detrimental for another. Implementation of inter-sectoral strategies that can benefit many sectors (such as water, labour and health) do exist and would enable optimal use of the meagre resources available. Discussion among inter-sectoral stakeholders should be actively encouraged.


2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Tamuno-owunari Perri ◽  
Vincent Ezikornwor Weli ◽  
Bright Poronakie ◽  
Tombari Bodo

Due to the visibility of soot in the environment of the Niger Delta especially Rivers State that has led to the increase of  espiratory Tract Infections (RTIs) in the region, this study was undertaken to determine the relationship between Particulate Matter (PM2.5) concentration and the incident of Respiratory Tract Infections (RTIs) in selected urban centres of the Niger Delta. Data on RTIs were collected from the Hospital Management Boards of the Ministries of Health of Rivers, Bayelsa and Delta States and the data for PM2.5 were remotely sensed from 2016 to 2019, and subsequently analyzed with ANOVA and Spearman’s rank correlation statistics. The findings of this study revealed that there was significant variation in the occurrence of PM2.5 across the selected urban centres in the Niger Delta Region. The PM2.5 for the reviewed years was far above the World Health Organization (WHO) annual permissible limit of 10 µg/m3 thereby exacerbating Respiratory Tract Infections (RTIs).The epidemiology of the RTIs showed that there are basically four (4) prominent RTI diseases: Asthma, Tuberculosis, Pneumonia and Chronic Obstructive Pulmonary Disease (COPD). The result of this study showed that the concentration of PM2.5 varies in all the selected cities, and the mean monthly variation (2016-2019) showed that Port Harcourt had 47.27 µg/m3 for January while Yenagoa and Asaba had 46 µg/m3 and 47.51 µg/m3 respectively for January; while the lowest mean value in the cities were seen within the month of September and October, which also had a strong seasonal influence on the concentration of PM2.5. The concentration of PM2.5 and the numbers of RTIs also gradually increases in the study areas from 2016 to 2019. The study recommends that the necessary regulatory bodies should closely monitor the activities of the companies likely to cause such pollution; guild them through their operations and give prompt sanctions and heavy fines to defaulters of the accepted standards.


2016 ◽  
Vol 81 (5) ◽  
pp. 273-280 ◽  
Author(s):  
O.M. Adedokun ◽  
◽  
M. Kyalo ◽  
B. Gnonlonfin ◽  
J. Wainaina ◽  
...  

Author(s):  
Oboshenure Kingsley Karo ◽  
Francis Emeka Egobueze ◽  
Davidson E. Egirani

The spatial variations in groundwater quality in parts of the Yenagoa watershed (YWS) in the Niger Delta Region of Nigeria has been investigated using Geographic Information System (GIS). An understanding of the factors responsible for groundwater vulnerability could facilitate the use of geographic information system in the control and management of groundwater quality. This study is due to the fact that the spatial distribution maps of groundwater quality in the YWS obtained by GIS modeling are not documented. The quality of groundwater accounts for the environmental and human health status of the residents in the YWS. Therefore, twenty (20) water samples obtained from shallow boreholes were analyzed for physicochemical properties. The physicochemical parameters such as pH, conductivity, total dissolved solids, sulphate, nitrate, sodium, chloride, magnesium, total hardness and iron contents were measured using standard laboratory procedure. Except for the iron content, the results obtained from the physicochemical analyses were within limits of the World Health Organization Standards for drinking water. These results were transformed into spatial distribution maps using GIS modeling and interpretation. The Index Overlay method and Inverse Distance weighted method form component parts of the GIS modeling used in the generation of the spatial distribution maps for each physicochemical parameter. These modeled results were related to the World Health Organization (WHO) Standard for drinking water. The maps generated from GIS modeling indicated zones that were suitable for groundwater extraction as opposed to zones unsuitable for groundwater extraction. In conclusion, 55% of the boreholes in the Yenagoa watershed were affected by high iron content.


2005 ◽  
Vol 20 (6) ◽  
pp. 399-403 ◽  
Author(s):  
Collette Roure ◽  
Asheena Khalakdina ◽  
Kumnuan Ungchusak ◽  
Media Yulizar ◽  
P. Ravindran ◽  
...  

AbstractThis is a summary of the presentations and discussion of Surveillance, Early Warning Alert and Response at the Conference, Health Aspects of the Tsunami Disaster in Asia, convened by the World Health Organization (WHO)in Phuket, Thailand, 04–06 May 2005. The topics discussed included issues related to the surveillance, early warning alert, and response to communicable and vector-borne diseases as pertaining to the responses to the damage created bythe Tsunami. It is presented in the following major sections: (1) key questions; (2) needs assessment; (3) coordination(4) gap filling; and (5) capacity building. The key questions section is presented in six sub-sections: (1) communicable diseases; (2) early warning; (3) laboratory capacity and referral networking; (4) coordination of disease surveillance, early warning, and response; (5) health infrastructure rebuilding; and (6) using existing national surveillance plans toenhance disease surveillance and early warning systems.


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