scholarly journals Wolbachia: endosymbiont of onchocercid nematodes and their vectors

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ranju Ravindran Santhakumari Manoj ◽  
Maria Stefania Latrofa ◽  
Sara Epis ◽  
Domenico Otranto

Abstract Background Wolbachia is an obligate intracellular maternally transmitted, gram-negative bacterium which forms a spectrum of endosymbiotic relationships from parasitism to obligatory mutualism in a wide range of arthropods and onchocercid nematodes, respectively. In arthropods Wolbachia produces reproductive manipulations such as male killing, feminization, parthenogenesis and cytoplasmic incompatibility for its propagation and provides an additional fitness benefit for the host to protect against pathogens, whilst in onchocercid nematodes, apart from the mutual metabolic dependence, this bacterium is involved in moulting, embryogenesis, growth and survival of the host. Methods This review details the molecular data of Wolbachia and its effect on host biology, immunity, ecology and evolution, reproduction, endosymbiont-based treatment and control strategies exploited for filariasis. Relevant peer-reviewed scientic papers available in various authenticated scientific data bases were considered while writing the review. Conclusions The information presented provides an overview on Wolbachia biology and its use in the control and/or treatment of vectors, onchocercid nematodes and viral diseases of medical and veterinary importance. This offers the development of new approaches for the control of a variety of vector-borne diseases. Graphic Abstract

Chemoecology ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 277-286
Author(s):  
Collins K. Mweresa ◽  
W. R. Mukabana ◽  
J. J. A. van Loon ◽  
M. Dicke ◽  
W. Takken

Abstract Reliance on broad-spectrum insecticides and chemotherapeutic agents to control hematophagous insect vectors, and their related diseases is threatened by increasing insecticide and drug resistance, respectively. Thus, development of novel, alternative, complementary and effective technologies for surveillance and control of such insects is strongly encouraged. Semiochemicals are increasingly developed for monitoring and intervention of insect crop pests, but this has not been adequately addressed for hematophagous insects of medical and veterinary importance. This review provides an insight in the application of semiochemicals for control of hematophagous insects. Here, we provide specific information regarding the isolation and identification of semiochemical compounds, optimization approaches, detection, perception and discrimination by the insect olfactory system. Navigation of insects along wind-borne odor plumes is discussed and methods of odor application in field situations are reviewed. Finally, we discuss prospects and future challenges for the application of semiochemical-based tools with emphasis on mosquitoes. The acquired knowledge can guide development of more effective components of integrated vector management, safeguard against emerging resistance of insects to existing insecticides and reduce the burden of vector-borne diseases.


Nova Scientia ◽  
2020 ◽  
Vol 12 (25) ◽  
Author(s):  
Rafael Vázquez-Marroquín ◽  
Mónica Duarte-Andrade ◽  
Luis Miguel Hernández-Triana ◽  
Aldo Iván Ortega-Morales ◽  
Rahuel Jeremías Chan-Chable

Introduction: Many mosquitoes are of great medical and veterinary importance because they transmit numerous pathogens which cause diseases in animals and humans; thus, knowing their taxonomy and distribution is pivotal for implementing the correct control strategies. The aim of this study was to determine the occurrence of mosquito species and their distribution in La Comarca Lagunera in the state of Durango, Mexico.Method: Adult mosquitoes were collected at different resting sites in four municipalities between August and November 2018 using Insectzookas. Aquatic habitats were also sampled for immature stages. Adult specimens were killed using lethal chambers with triethylamine vapors; while larvae and pupae were stored in individual tubes to obtain the adult stages and associated exuviae. All material was transported to the Molecular Biology Laboratory of the Parasitology Department of the Universidad Autónoma Agraria Antonio Narro, Unidad Laguna (UAAAN-UL) for mounting and taxonomical identification. Species were identified using taxonomic keys for the region.Results: In total, 689 mosquito specimens (286 males and 403 females) were collected belonging to 15 species, among them Anopheles franciscanus McCracken, Culex erythrothorax Dyar, and Toxorhynchites moctezuma (Dyar and Knab) are new records for Durango State. The most abundant species was Cx. quinquefasciatus Say with 364 (56.2%) specimens, followed by Aedes aegypti (Linnaeus) (21.3%) and Ae. vexans (Meigen) (7.7%).Conclusion: 13 out of 15 species collected are associated with the transmission of an arbovirus of relevant medical or veterinary importance in Mexico. There are now 38 species recorded for Durango. The information in this study is directly relevant for the Health Ministry in Durango State for the control of vector borne diseases in the region.


2021 ◽  
Author(s):  
Winnie Paulson ◽  
Karuppusamy Balasubramani ◽  
Rashi Dixit ◽  
Savitha Chellappan ◽  
Sujit Kumar Behera ◽  
...  

Abstract BackgroundDengue and chikungunya (CHIKV) are the two major vector-borne diseases of serious public health concern in India. Studies on socio-economic and housing determinants of dengue and CHIKV at a pan-India level are lacking. Here, we took advantage of the recently carried out Longitudinal Ageing Study in India (LASI) carried across all the States and Union Territories of India to study the social determinants of dengue and CHIKV in India.MethodsLASI-1 (2017-2018) data on the self-reported period prevalence of dengue and CHIKV from 70,865 respondents aged ≥45 years were used for this analysis. The State-wise distribution of dengue and CHIKV was mapped. Prevalence was estimated for each study variable, and the difference was compared using the χ2 test. The adjusted odds ratios (AOR) of the socio-economic and housing variables for dengue and CHIKV were calculated using a multiple logistic regression model.ResultsUrban residence is the major socio-economic determinant of dengue and CHIKV (dengue: AOR: 1.57, 95% CI: 1.17-2.10; CHIKV: AOR 1.56, 95% CI: 1.20-2.02). Wealth status (richest) and less than primary schooling are associated with dengue and CHIKV prevalence. In addition to these factors, social group (scheduled and forward castes) is also associated with CHIKV prevalence. Water-source outside the dwelling (AOR: 1.20, 95% CI: 0.96-1.50), pucca or semi- pucca house type are also associated with increased odds of CHIKV. ConclusionsDespite the limitation that the data is only from adults ≥ 45, this analysis provides important insights into the socio-economic and housing variables that increase the odds of dengue and CHIKV in India. Understanding these determinants may assist in the national planning of prevention and control strategies for dengue and CHIKV.


2019 ◽  
Vol 33 (6) ◽  
pp. 478-493
Author(s):  
Shanker Bahadur Shrestha ◽  
Uttam Raj Pyakurel ◽  
Mukti Khanal ◽  
Murari Upadhyay ◽  
Kesara Na-Bangchang ◽  
...  

Purpose The purpose of this paper is to investigate epidemiology and control strategies of the four priority vector-borne diseases (VBDs) in Nepal, i.e. malaria, Kala-azar (visceral leishmaniasis), lymphatic filariasis (LF) and dengue fever/dengue hemorrhagic fever. Design/methodology/approach The study was a retrospective design to collect data during 1998–2016 from VBDs endemic districts of Nepal. All data were reviewed and epidemiological information of the four VBDs were analyzed. Findings The number of malaria cases during 1998–2016 of the 13 affected districts was declined from 8,498 to 991 cases with no record of deaths since 2012. The number of cases and deaths in the 12 kala-azar (visceral leishmaniasis) affected districts in 1998 was 1,409 and 42 cases, respectively, but was dramatically decreased in 2016 to 213 and 2 cases, respectively. LF cases of the 61 affected districts in 2011, 2014 and 2016 were 28,855, 30,000 and 33,517 cases, respectively. In total, 25 districts achieved elimination target and the remaining are expected to complete the needful cycles by 2018. Dengue incidence of the 31 affected districts during 2006–2015 was under controlled with reported cases of 642, 356 and 136 cases in 2013, 2014 and 2015, respectively, and only one death in 2015. Implementation of control strategies particularly disease management and community peoples’ awareness significantly reduced the cases and deaths of the target VBDs. Practical implications The results of this study clearly suggest that the current control strategies have been worked effectively. However, in particular of the VBDs, health education in communities in the endemic areas should be adopted for better community participation in the context of the primary health care approach and increase the effectiveness of disease control. Originality/value VBDs, i.e., malaria, kala-azar (visceral leishmaniasis), LF and dengue fever/dengue hemorrhagic fever, are major causes of morbidity and mortality in the least developed countries which include Nepal. Globalization of travel and trading, unplanned urbanization, environmental and climate change are having a significant impact on disease transmission. Therefore, the Ministry of Health of Nepal had brought some changes in strategies based on activities for disease control, vector control, preventive and preparedness for outbreak response. Consequently, the cases and deaths due to malaria, kala-azar (visceral leishmaniasis), lymphatic filaiasis and dengue fever/dengue hemorrhagic fever have been brought down markedly.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ana Mafalda Dordio ◽  
Relja Beck ◽  
Telmo Nunes ◽  
Isabel Pereira da Fonseca ◽  
Jacinto Gomes

Abstract Background Canine vector-borne diseases (CVBDs) are caused by a wide range of pathogens transmitted by arthropods. They have been an issue of growing importance in recent years; however, there is limited information about the vector-borne pathogens circulating in Portugal. The aim of the present study was to detect canine vector-borne bacteria and protozoa of veterinary and zoonotic importance using molecular methods. Methods One hundred and forty-two dogs from Lisbon, southern Portugal, were tested: 48 dogs from a veterinary hospital clinically suspected of vector-borne diseases and 94 apparently healthy dogs from shelters. Anaplasma spp./Ehrlichia spp., Babesia/Theileria spp., Hepatozoon spp., and Mycoplasma spp. infections were detected by PCR from blood samples and examined under light microscopy. Other information including clinical status and diagnostic test results were collected for each animal. Results Infections were detected by PCR in 48 (33.80%) dogs. Single infections were found in 35 dogs (24.64%), and co-infections were found in 13 (9.15%) dogs. Twenty-nine (20.42%) dogs were positive for Hepatozoon spp., 15 (10.56%) for Mycoplasma spp., 11 (7.75%) for Anaplasma spp./Ehrlichia spp., and six (4.21%) for Babesia spp. DNA sequencing was used to identify Babesia vogeli (2.81%), Babesia canis (1.40%), Hepatozoon canis (20.42%), Mycoplasma haematoparvum (2.11%), Mycoplasma haemocanis (8.45%), Anaplasma platys (7.04%), and Ehrlichia canis (0.70%). Conclusions This is the first molecular identification of B. canis and M. haematoparvum in dogs from southern Portugal. This study highlights the importance of molecular methods to identify CVBD pathogens in endemic areas and helps to guide the clinical approach of veterinarians in practice.


Author(s):  
Sadie J. Ryan ◽  
Catherine A. Lippi ◽  
Kevin L. Bardosh ◽  
Erika F. Frydenlund ◽  
Holly D. Gaff ◽  
...  

Vector borne diseases (VBDs) are often seen by the highly developed nations of the world as an issue of poor tropical countries. While framing the problem this way—through the paradigm of a poverty-trap—may leverage aid and motivate political will toward disease control, it misses a wide range of socio-political contexts both driving, and driven by, vector borne diseases. In this chapter, we present a series of global vignettes, to illustrate different facets of the broad remit of social drivers and interactions with VBDs. We approach the urban social-ecological context in Latin America and the Caribbean, impacts and aftermath of natural disasters such as earthquakes and tropical storms, struggles with trust in intervention implementation in Haiti, and drivers and impacts of ruminant arbovirus emergence events in Europe. We conclude that incorporating an understanding of social context, including political history and cultural perceptions, is a key part of VBD research and intervention practice.


2017 ◽  
Vol 31 (1) ◽  
Author(s):  
Ann M. Powers

SUMMARYBeginning in 2004, chikungunya virus (CHIKV) went from an endemic pathogen limited to Africa and Asia that caused periodic outbreaks to a global pathogen. Given that outbreaks caused by CHIKV have continued and expanded, serious consideration must be given to identifying potential options for vaccines and therapeutics. Currently, there are no licensed products in this realm, and control relies completely on the use of personal protective measures and integrated vector control, which are only minimally effective. Therefore, it is prudent to urgently examine further possibilities for control. Vaccines have been shown to be highly effective against vector-borne diseases. However, as CHIKV is known to rapidly spread and generate high attack rates, therapeutics would also be highly valuable. Several candidates are currently being developed; this review describes the multiple options under consideration for future development and assesses their relative advantages and disadvantages.


Author(s):  
Marilyn Joyce ◽  
Andrew J. Marcotte ◽  
Richard Barker ◽  
Edward J. Klinenberg

A methodology for identifying ergonomics risk factors and control strategies in office environments has been developed and pilot tested. Developed as part of an overall ergonomics program being implemented by the United States Air Force, the employees impacted include both civilian and military personnel performing a wide range of administrative tasks typically performed in offices. The research design included: a focused literature review; strategic site visits; and review of criteria established by the Air Force; an iterative developmental process of a Screening Survey and an Ergonomics Assessment Methodology Guide; and testing. The results indicate that the process can be used as an effective means for identifying and controlling ergonomics hazards in administrative work areas.


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