scholarly journals Impact of housing condition on indoor-biting and indoor-resting Anopheles arabiensis density in a highland area, central Ethiopia

2013 ◽  
Vol 12 (1) ◽  
Author(s):  
Abebe Animut ◽  
Meshesha Balkew ◽  
Bernt Lindtjørn
2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Kasahun Eba ◽  
Tibebu Habtewold ◽  
Delenasaw Yewhalaw ◽  
George K. Christophides ◽  
Luc Duchateau

Abstract Background Understanding malaria vector’s population dynamics and their spatial distribution is important to define when and where the largest infection risks occur and implement appropriate control strategies. In this study, the seasonal spatio-temporal dynamics of the malaria vector population and transmission intensity along intermittent rivers in a semi-arid area of central Ethiopia were investigated. Methods Mosquitoes were collected monthly from five clusters, 2 close to a river and 3 away from a river, using pyrethrum spray catches from November 2014 to July 2016. Mosquito abundance was analysed by the mixed Poisson regression model. The human blood index and sporozoite rate was compared between seasons by a logistic regression model. Results A total of 2784 adult female Anopheles gambiae sensu lato (s.l.) were collected during the data collection period. All tested mosquitoes (n = 696) were identified as Anopheles arabiensis by polymerase chain reaction. The average daily household count was significantly higher (P = 0.037) in the clusters close to the river at 5.35 (95% CI 2.41–11.85) compared to the clusters away from the river at 0.033 (95% CI 0.02–0.05). Comparing the effect of vicinity of the river by season, a significant effect of closeness to the river was found during the dry season (P = 0.027) and transition from dry to wet season (P = 0.032). Overall, An. arabiensis had higher bovine blood index (62.8%) as compared to human blood index (23.8%), ovine blood index (9.2%) and canine blood index (0.1%). The overall sporozoite rate was 3.9% and 0% for clusters close to and away from the river, respectively. The overall Plasmodium falciparum and Plasmodium vivax entomologic inoculation rates for An. arabiensis in clusters close to the river were 0.8 and 2.2 infective bites per person/year, respectively. Conclusion Mosquito abundance and malaria transmission intensity in clusters close to the river were higher which could be attributed to the riverine breeding sites. Thus, vector control interventions including targeted larval source management should be implemented to reduce the risk of malaria infection in the area.


Author(s):  
Trần Thanh Đức

<p>Vietnam is a country that is suffered from frequent natural disasters. The most common types of natural disasters experienced are typhoon and flood. From 1951 to 2010, there were 166 typhoons come to Vietnam, of which 67 % hit the central region, 25 % to the north and 8 % to the south of the country. Typhoons bring heavy rains and high tides which accelerate floods, particularly in the coastal and lagoon areas of Central Vietnam. Identification of vulnerability to flooding and coping behavior of local people is required in the efforts to strengthen local capacity related to livelihood security in the study area. This study aims at characterizing the vulnerability of housing condition to flooding and the coping behaviors of local people after experienced big floods in Tam Giang lagoon area, Central Vietnam. Measurement of house’s foundation, observation of types of housing, interview to collect information about the water level during the events of big floods, year of construction and change of people’s behavior after the 1999’s flood were conducted with 427 households in Van Quat Dong village where four big flooding occurred in 1983, 1999, 2007 and 2009 during the last 30 years. The study shows that the 1999’s flood was the biggest flood with water height reached to 148.7 ± 23.9 cmfrom house floor and 222.6 ± 15.4 cmfrom ground level. The households located in the eastern part of the village are recognized more vulnerable to flood due to the lower altitude. The temporary and semi-permanent houses, which share 77.0 % to the entire houses, are considered to be relatively vulnerable to flooding due to weak housing materials and low height of foundation. The houses which categorized to permanent and semi-permanent types constructed after the 1999’s flood have higher foundation than the other houses constructed before the 1999’s flood. The raising of foundation height of permanent and semi-permanent houses, as well as an increase in numbers of two-storey houses, are recognized to be a behavior of local people to cope with flooding. The study also shows the relationship between the poverty level and the coping behaviors of households. Some of poor households in the village are still not in good preparedness to flooding. It suggests that poverty level of household concerns to the vulnerability to flooding and, therefore, rural development assistance to improve household economy for poverty alleviation is required in the efforts to strengthen local capacity related to livelihood security.<strong></strong></p>


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Blaženka D. Letinić ◽  
Marinela Contreras ◽  
Yael Dahan-Moss ◽  
Ingrid Linnekugel ◽  
José de la Fuente ◽  
...  

Abstract Background Anopheles arabiensis is an opportunistic malaria vector that rests and feeds outdoors, circumventing current indoor vector control methods. Furthermore, this vector will readily feed on both animals and humans. Targeting this vector while feeding on animals can provide an additional intervention for the current vector control activities. Previous results have displayed the efficacy of using Subolesin/Akirin ortholog vaccines for the control of multiple ectoparasite infestations. This made Akirin a potential antigen for vaccine development against An. arabiensis. Methods The efficacy of three antigens, namely recombinant Akirin from An. arabiensis, recombinant Akirin from Aedes albopictus, and recombinant Q38 (Akirin/Subolesin chimera) were evaluated as novel interventions for An. arabiensis vector control. Immunisation trials were conducted based on the concept that mosquitoes feeding on vaccinated balb/c mice would ingest antibodies specific to the target antigen. The antibodies would interact with the target antigen in the arthropod vector, subsequently disrupting its function. Results All three antigens successfully reduced An. arabiensis survival and reproductive capacities, with a vaccine efficacy of 68–73%. Conclusions These results were the first to show that hosts vaccinated with recombinant Akirin vaccines could develop a protective response against this outdoor malaria transmission vector, thus providing a step towards the development of a novel intervention for An. arabiensis vector control. Graphic Abstract


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