scholarly journals Activation of mosquito immunity blocks the development of transmission-stage filarial nematodes

2020 ◽  
Vol 117 (7) ◽  
pp. 3711-3717 ◽  
Author(s):  
Elizabeth B. Edgerton ◽  
Abigail R. McCrea ◽  
Corbett T. Berry ◽  
Jenny Y. Kwok ◽  
Letitia K. Thompson ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Pathogen Transmission ◽  
Susceptible Strain ◽  
Helminth Infections ◽  
Immune Signaling Pathway ◽  
Filarial Nematodes ◽  
Canine Heartworm Disease ◽  
Heartworm Disease ◽  
Transmission Stage ◽  
Nematode Development

Mosquito-borne helminth infections are responsible for a significant worldwide disease burden in both humans and animals. Accordingly, development of novel strategies to reduce disease transmission by targeting these pathogens in the vector are of paramount importance. We found that a strain of Aedes aegypti that is refractory to infection by Dirofilaria immitis, the agent of canine heartworm disease, mounts a stronger immune response during infection than does a susceptible strain. Moreover, activation of the Toll immune signaling pathway in the susceptible strain arrests larval development of the parasite, thereby decreasing the number of transmission-stage larvae. Notably, this strategy also blocks transmission-stage Brugia malayi, an agent of human lymphatic filariasis. Our data show that mosquito immunity can play a pivotal role in restricting filarial nematode development and suggest that genetically engineering mosquitoes with enhanced immunity will help reduce pathogen transmission.

scholarly journals Canine heartworm disease in Porto Velho: first record, distribution map and occurrence of positive mosquitoes

2013 ◽  
Vol 22 (4) ◽  
pp. 559-564 ◽  
Author(s):  
Guilherme Maerschner Ogawa ◽  
Edson Neves da Cruz ◽  
Príscila Nayara Araújo Cunha ◽  
Luís Marcelo Aranha Camargo
Keyword(s):  
Disease Transmission ◽  
Pulmonary Nodules ◽  
First Record ◽  
Blood Samples ◽  
Canine Heartworm ◽  
Blood Smears ◽  
Canine Heartworm Disease ◽  
Heartworm Disease ◽  
The City ◽  
Porto Velho

The aim of this study was to make the first report on canine heartworm disease in the state of Rondônia and confirm its transmission in this state. Blood samples were randomly collected from 727 dogs in the city of Porto Velho. The samples were analyzed to search for microfilariae and circulating antigens, using three different techniques: optical microscopy on thick blood smears stained with Giemsa; immunochromatography; and PCR. Mosquitoes were collected inside and outside the homes of all the cases of positive dogs and were tested using PCR to search for DNA of Dirofilaria immitis. Ninety-three blood samples out of 727 (12.8%) were positive according to the immunoassay technique and none according to the thick smear method. Among the 93 positive dogs, 89 (95.7%) were born in Porto Velho. No difference in the frequency of infection was observed between dogs raised indoors and in the yard. PCR on the mosquitoes resulted in only one positive pool. This result shows that the transmission of canine heartworm disease is occurring in the city of Porto Velho and that there is moderate prevalence among the dogs. The techniques of immunochromatography and PCR were more effective for detecting canine heartworm than thick blood smears. The confirmation of canine heartworm disease transmission in Porto Velho places this disease in the ranking for differential diagnosis of pulmonary nodules in humans in Rondônia.

scholarly journals Quantity and Quality of Aquaculture Enrichments Influence Disease Epidemics and Provide Ecological Alternatives to Antibiotics

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 335
Author(s):  
Anssi Karvonen ◽  
Ville Räihä ◽  
Ines Klemme ◽  
Roghaieh Ashrafi ◽  
Pekka Hyvärinen ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Bacterial Infections ◽  
Environmental Heterogeneity ◽  
Pathogen Transmission ◽  
Central Component ◽  
Flavobacterium Columnare ◽  
Disease Epidemics ◽  
The Impact ◽  
Environmental Microbes

Environmental heterogeneity is a central component influencing the virulence and epidemiology of infectious diseases. The number and distribution of susceptible hosts determines disease transmission opportunities, shifting the epidemiological threshold between the spread and fadeout of a disease. Similarly, the presence and diversity of other hosts, pathogens and environmental microbes, may inhibit or accelerate an epidemic. This has important applied implications in farming environments, where high numbers of susceptible hosts are maintained in conditions of minimal environmental heterogeneity. We investigated how the quantity and quality of aquaculture enrichments (few vs. many stones; clean stones vs. stones conditioned in lake water) influenced the severity of infection of a pathogenic bacterium, Flavobacterium columnare, in salmonid fishes. We found that the conditioning of the stones significantly increased host survival in rearing tanks with few stones. A similar effect of increased host survival was also observed with a higher number of unconditioned stones. These results suggest that a simple increase in the heterogeneity of aquaculture environment can significantly reduce the impact of diseases, most likely operating through a reduction in pathogen transmission (stone quantity) and the formation of beneficial microbial communities (stone quality). This supports enriched rearing as an ecological and economic way to prevent bacterial infections with the minimal use of antimicrobials.

Promising Role of Wolbachia as Anti-parasitic Drug Target and Eco-Friendly Biocontrol Agent

2019 ◽  
Vol 14 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Tooran Nayeri Chegeni ◽  
Mahdi Fakhar
Keyword(s):  
Drug Target ◽  
Biocontrol Agent ◽  
Pathogen Transmission ◽  
Parasitic Diseases ◽  
Pests And Diseases ◽  
Filarial Nematodes ◽  
Reproductive Incompatibility ◽  
Vector Borne ◽  
Potential Strategy

Background: Wolbachia is the most common endosymbiotic bacteria in insectborne parasites and it is the most common reproductive parasite in the world. Wolbachia has been found worldwide in numerous arthropod and parasite species, including insects, terrestrial isopods, spiders, mites and filarial nematodes. There is a complicated relationship between Wolbachia and its hosts and in some cases, they create a mutual relationship instead of a parasitic relationship. Some species are not able to reproduce in the absence of infection with Wolbachia. Thus, the use of existing strains of Wolbachia bacteria offers a potential strategy for the control of the population of mosquitoes and other pests and diseases. Methods: We searched ten databases and reviewed published papers regarding the role of Wolbachia as a promising drug target and emerging biological control agents of parasitic diseases between 1996 and 2017 (22 years) were considered eligible. Also, in the current study several patents (WO008652), (US7723062), and (US 0345249 A1) were reviewed. Results: Endosymbiotic Wolbachia bacteria, which are inherited from mothers, is transmitted to mosquitoes and interferes with pathogen transmission. They can change the reproduction of their host. Wolbachia is transmitted through the cytoplasm of eggs and have evolved different mechanisms for manipulating the reproduction of its hosts, including the induction of reproductive incompatibility, parthenogenesis, and feminization. The extensive effects of Wolbachia on reproduction and host fitness have made Wolbachia the issue of growing attention as a potential biocontrol agent. Conclusion: Wolbachia has opened a new window to design a costly, potent and ecofriendly drug target for effective treatment and elimination of vector-borne parasitic diseases.

An investigation of the role of immunologic factors in anemia associated with canine heartworm disease

1984 ◽  
Vol 7 (3-4) ◽  
pp. 285-292 ◽  
Author(s):  
L.L. Werner ◽  
R.E.W. Halliwell ◽  
R.F. Jackson ◽  
T.C. Needham ◽  
M. Limpach
Keyword(s):  
Canine Heartworm ◽  
Canine Heartworm Disease ◽  
Heartworm Disease ◽  
Immunologic Factors

scholarly journals Feeder density enhances house finch disease transmission in experimental epidemics

2018 ◽  
Vol 373 (1745) ◽  
pp. 20170090 ◽  
Author(s):  
Sahnzi C. Moyers ◽  
James S. Adelman ◽  
Damien R. Farine ◽  
Courtney A. Thomason ◽  
Dana M. Hawley
Keyword(s):  
Radio Frequency Identification ◽  
Disease Transmission ◽  
Bacterial Pathogen ◽  
Pathogen Transmission ◽  
House Finch ◽  
Resource Subsidies ◽  
House Finches ◽  
Bird Feeders ◽  
Group Members ◽  
Radio Frequency Identification Devices

Anthropogenic food provisioning of wildlife can alter the frequency of contacts among hosts and between hosts and environmental sources of pathogens. Despite the popularity of garden bird feeding, few studies have addressed how feeders influence host contact rates and disease dynamics. We experimentally manipulated feeder density in replicate aviaries containing captive, pathogen-naive, groups of house finches ( Haemorhous mexicanus ) and continuously tracked behaviours at feeders using radio-frequency identification devices. We then inoculated one bird per group with Mycoplasma gallisepticum (Mg), a common bacterial pathogen for which feeders are fomites of transmission, and assessed effects of feeder density on house finch behaviour and pathogen transmission. We found that pathogen transmission was significantly higher in groups with the highest density of bird feeders, despite a significantly lower rate of intraspecific aggressive interactions relative to the low feeder density groups. Conversely, among naive group members that never showed signs of disease, we saw significantly higher concentrations of Mg-specific antibodies in low feeder density groups, suggesting that birds in low feeder density treatments had exposure to subclinical doses of Mg. We discuss ways in which the density of garden bird feeders could play an important role in mediating the intensity of Mg epidemics. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife'.

scholarly journals Ungulate use of locally infectious zones in a re-emerging anthrax risk area

2020 ◽  
Vol 7 (10) ◽  
pp. 200246 ◽  
Author(s):  
Morgan A. Walker ◽  
Maria Uribasterra ◽  
Valpa Asher ◽  
José Miguel Ponciano ◽  
Wayne M. Getz ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Control Strategies ◽  
Pathogen Transmission ◽  
Camera Traps ◽  
Risk Area ◽  
Southwestern Montana ◽  
Increased Risk ◽  
Anthrax Spores ◽  
Causative Bacterium ◽  
And Control

Environmentally mediated indirect pathogen transmission is linked to host movement and foraging in areas where pathogens are maintained in the environment. In the case of anthrax, spores of the causative bacterium Bacillus anthracis are released into the environment following host death and create locally infectious zones (LIZs) around carcass sites; by grazing at LIZs, herbivores are potentially exposed to spores. Here, we used camera traps to assess how ungulate species use carcass sites in southwestern Montana and evaluated how these behaviours may promote indirect anthrax transmission, thus providing, to our knowledge, the first detailed documentation and study of the fine-scale mechanisms underlying foraging-based disease transmission in this ecosystem. We found that carcasses at LIZs significantly increased aboveground biomass of vegetation and concentrations of sodium and phosphorus, potentially making these sites more appealing to grazers. Host behavioural responses to LIZs varied depending on species, sex, season and carcass age; but, overall, our results demonstrated that carcasses or carcass sites serve as an attractant to herbivores in this system. Attraction to LIZs probably represents an increased risk of exposure to B. anthracis and, consequently, increased anthrax transmission rates. Accordingly, continued anthrax surveillance and control strategies are critical in this system.

Seroprevalence of canine heartworm disease (Dirofilaria immitis) on Tenerife Island: an epidemiological update

2006 ◽  
Vol 100 (1) ◽  
pp. 103-105 ◽  
Author(s):  
J. A. Montoya ◽  
M. Morales ◽  
M. C. Juste ◽  
A. Bañares ◽  
F. Simon ◽  
...  
Keyword(s):  
Dirofilaria Immitis ◽  
Canine Heartworm ◽  
Canine Heartworm Disease ◽  
Heartworm Disease ◽  
Tenerife Island
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