scholarly journals Evidence of circulation of Orthobunyaviruses in diverse mosquito species in Kwale County, Kenya

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Hellen Koka ◽  
Joel Lutomiah ◽  
Solomon Langat ◽  
Edith Koskei ◽  
Albert Nyunja ◽  
...  

Abstract Background Arbovirus surveillance and recurrence of outbreaks in Kenya continues to reveal the re-emergence of viruses of public health importance. This calls for sustained efforts in early detection and characterization of these agents to avert future potential outbreaks. Methods A larval survey was carried out in three different sites in Kwale County, Vanga, Jego and Lunga Lunga. All containers in every accessible household and compound were sampled for immature mosquitoes. In addition, adult mosquitoes were also sampled using CO2-baited CDC light traps and BG-Sentinel traps in the three sites and also in Tsuini. The mosquitoes were knocked down using trimethylamine and stored in a liquid nitrogen shipper for transportation to the laboratory where they were identified to species, pooled and homogenized ready for testing. Results A total of 366 houses and 1730 containers were inspected. The House Index (HI), Container Index (CI) and Breateau Index (BI) for Vanga Island were (3%: 0.66: 3.66) respectively. In Jego, a rural site, the HI, CI and BI were (2.4%: 0.48: 2.4) respectively. In Lunga Lunga, a site in an urban area, the HI, CI and BI were (22.03%: 3.97: 29.7) respectively. The indices suggest that this region is at risk of arbovirus transmission given they were above the WHO threshold (CI > 1, HI > 1% and BI > 5). The most productive containers were the concrete tanks (44.4%), plastic tank (22.2%), claypot (13.3%), plastic drums (8.9%), plastic basins (4%), jerricans (1.2%) and buckets (0.3%). Over 20,200 adult mosquitoes were collected using CDC light traps, and over 9,200 using BG- sentinel traps. These mosquitoes were screened for viruses by inoculating in Vero cells. Eleven Orthobunyavirus isolates were obtained from pools of Ae. pembaensis (4), Ae. tricholabis (1), Cx. quinquefasciatus (3), Culex spp. (1) and Cx. zombaensis (2). Five of the Orthobunyaviruses were sequenced and four of these were determined to be Bunyamwera viruses while one isolate was found to be Nyando virus. One isolate remained unidentified. Conclusions These results indicate circulation of Orthobunyaviruses known to cause diverse grades of febrile illness with rash in humans in this region and highlights the need for continued monitoring and surveillance to avert outbreaks.

2009 ◽  
Vol 46 (6) ◽  
pp. 1494-1497 ◽  
Author(s):  
Stephanie L. White ◽  
Michael P. Ward ◽  
Christine M. Budke ◽  
Tracy Cyr ◽  
Rudy Bueno

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 194 ◽  
Author(s):  
Anthony J. Cornel ◽  
Jodi Holeman ◽  
Catelyn C. Nieman ◽  
Yoosook Lee ◽  
Charles Smith ◽  
...  

The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas.


F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 194 ◽  
Author(s):  
Anthony J. Cornel ◽  
Jodi Holeman ◽  
Catelyn C. Nieman ◽  
Yoosook Lee ◽  
Charles Smith ◽  
...  

The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas.


F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 194 ◽  
Author(s):  
Anthony J. Cornel ◽  
Jodi Holeman ◽  
Catelyn C. Nieman ◽  
Yoosook Lee ◽  
Charles Smith ◽  
...  

The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas.


Author(s):  
Timothy D McNamara ◽  
Thomas A O’Shea-Wheller ◽  
Nicholas DeLisi ◽  
Emily Dugas ◽  
Kevin A Caillouet ◽  
...  

Abstract West Nile virus (WNV) is the most prevalent arbovirus found throughout the United States. Surveillance of surface breeding Culex vectors involved in WNV transmission is primarily conducted using CDC Gravid traps. However, anecdotal claims from mosquito abatement districts in Louisiana assert that other trap types may be more suited to WNV surveillance. To test the validity of these assertions, we conducted a series of trapping trials and WNV surveillance over 3 yr to compare the efficacy of multiple trap types. First, we compared the CDC Gravid trap, CO2-baited New Standard Miniature Blacklight traps, and CO2-baited CDC light traps with either an incandescent light, a red light, or no light. We found that the CDC Gravid trap and CO2-baited no-light CDC Light trap collected the most mosquitoes. Second, we conducted additional, long-term trapping and WNV surveillance to compare these two trap types. We found that CO2-baited no-light CDC traps collected more of the local WNV vector, Culex quinquefasciatus (Say, Diptera, Culicidae), and detected WNV with greater sensitivity. Finally, we conducted trapping to compare the physiological states of Cx. quinquefasciatus and diversity of collected mosquitoes. CO2-baited no-light CDC light traps collected more unfed Cx. quinquefasciatus while Gravid traps collected more blooded Cx. quinquefasciatus; both traps collected the same number of gravid Cx. quinquefasciatus. Additionally, we found that CO2-baited no-light CDC light traps collected a larger diversity of mosquito species than Gravid traps.


F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 82 ◽  
Author(s):  
Lyle R. Petersen ◽  
Ann M. Powers

Chikungunya virus is a mosquito-borne alphavirus that causes fever and debilitating joint pains in humans. Joint pains may last months or years. It is vectored primarily by the tropical and sub-tropical mosquito, Aedes aegypti, but is also found to be transmitted by Aedes albopictus, a mosquito species that can also be found in more temperate climates. In recent years, the virus has risen from relative obscurity to become a global public health menace affecting millions of persons throughout the tropical and sub-tropical world and, as such, has also become a frequent cause of travel-associated febrile illness. In this review, we discuss our current understanding of the biological and sociological underpinnings of its emergence and its future global outlook.


2021 ◽  
pp. 14-17
Author(s):  
B.Bhaskar Rao ◽  
Jayakrishnan Thayyil ◽  
Biju George ◽  
Athira. T

Effective surveillance and monitoring of Aedes albopictus is essential for the possible prediction and implementation of the preventive measures. We tested BG sentinel mosquitito traps with BG lure to collect adults as an alternative surveillance tool in relation to larval indices. Study was carried out in Calicut District, Kerala, India. Three villages in the district were selected by random sampling as study area. In each village, 50 houses were selected as study site for trap collection, larval survey and fever surveillance. Study was conducted for six months from July to December, 2017. Number of adults of Ae.albopictus collected in BG sentinel traps was only 84 in 22 collections spanning over six months (mean 3.82, 95% CI-2.57-5.06).Though the larval indices were high; no epidemic was reported from the study area. There was no correlation between adults collected and larval indices. Adult collection showed a positive correlation with most of meteorological parameters. Larval indices showed no correlation with climatic factors.BG mosquitito trap was found to be not successful for adult surveillance in the area. More studies are required using different traps to suggest adult traps as an alternative to currently used larval indices. Larval indices were high but no cases reported. Our study shows that a more reliable monitoring mechanism is required for Ae.albopictus to enable prevention, to introduce abatement and its evaluation.


2021 ◽  
Vol 1 (1) ◽  
pp. 27-35
Author(s):  
Nantip F. Miri

Background: Despite the public health importance of dengue infections, it is less investigated by clinicians and rarely considered in the differential diagnosis of febrile illnesses in Nigeria. The objective was to detect the presence of Dengue IgG/IgM antibodies and Plasmodium species in the blood of febrile patients. Methods: This is a cross sectional study conducted among ninety-four (94) consenting febrile patients suspected of malaria in Jos. Duo detection of dengue antibodies (IgG/IgM) were determined by ELISA technique. Total DNA was extracted from patient serum and quantified to determine concentration and quality of the extraction process. Malaria was detected by Real Time Polymerase Chain Reaction. Results: Dengue antibodies were detected in 55.3% (52/94) of the febrile patients. The mean age was 29.9±1.2. Highest dengue prevalence of 75% (39/52), 50% (26/52) and 59.6% (31/52) were recorded among females, students and non-users of mosquito nets, respectively. In all. 11.7% (11/94) of the samples tested positive for malaria. Age group 11-20 years recorded the highest prevalence of malaria, 63.6% (7/11). Dengue and Malaria co-infection was documented in 5.3% (5/94). There was a significant difference in the prevalence of dengue and malaria among febrile subjects. Conclusion: No association of dengue infection with gender and use of Insecticide Treated Nets was found. The lower malaria prevalence compared to dengue suggests that febrile illness in this population is shown to be associated more with dengue infection. We recommend a continuous surveillance of dengue infection in this population and consideration of dengue in the differential diagnosis of febrile illnesses.


the dosages used to kill mosquitoes, non-target organisms are safe. Both of these products, especially Bacillus, break down quickly and should therefore present no hazard to water quality. Given that a site such as Big Bay may become a mecca for those wishing to swim, sail or even fish, a surveillance programme and some environmental modifications are necessary. The deeper open waters of this bay coupled with a vegetation-free foreshore as a buffer zone, perhaps 400 m on either side of a swimming zone, should minimize or even negate swimmer’s itch. Adjacent Hydrilla and other macrophytes will require clearing as these will also present a physical hazard to swimmers and watercraft. The monitoring programmes could ideally be done three to four weeks prior to extensive public usage to allow time for any remedial action. The prevalence of key mosquito species and of large Austropeplea (and Gyraulus and Amerianna) snails can be established quickly as can cercarial infection in the snails. If it is found necessary to establish infection rates in mosquitoes, the newly developed Ross River and Barmah Forest virus testing procedures using mosquito cell cultures and enzyme immunosorbent assay (Oliveira et al. 1995) would require six days processing time. This offers considerable economy over previous methods using intracerebral inoculation of baby suckling mice. We would suggest that prior to selected recreational events, especially those from March to May, the Water Supply Board should initiate the action shown in Figure 9.6. The information supplied in response to a request should be communicated to recreational users to ensure that they are aware of the risks. Perhaps mosquito, arbovirus, and schistosome status could be displayed in the same way as fire hazard status is commonly indicated. It would be remiss of us to generate the impression that we had all the answers to the Ross River dam. The stage 2A lake and its surrounds are undergoing a process of ecological change and realization of this must remain paramount. There are issues relating to mosquito biology and behaviour and to do with snail ecology generally that would repay further study. Thus further selective monitoring and research should not be forsaken. References

1998 ◽  
pp. 155-157

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