Experimental comparison of Baylisascaris procyonis definitive host competence between domestic dogs and raccoons (Procyon lotor)

Parasitology ◽  
2020 ◽  
Vol 147 (12) ◽  
pp. 1344-1351
Author(s):  
Sarah G. H. Sapp ◽  
David A. Elsemore ◽  
Rita Hanna ◽  
Michael J. Yabsley
Keyword(s):  
Definitive Host ◽  
Human Exposure ◽  
Low Dose ◽  
Control Measures ◽  
Domestic Dogs ◽  
Experimental Comparison ◽  
Laboratory Mice ◽  
Baylisascaris Procyonis ◽  
Infection Dynamics ◽  
Host Competence

AbstractDomestic dogs can function as either paratenic or definitive hosts for the zoonotic raccoon roundworm Baylisascaris procyonis. However, factors leading to development of patent infections in dogs are under-studied. Here we compared infection dynamics of B. procyonis in dogs vs the natural raccoon host. Dogs and raccoons were inoculated 5000 or 500 B. procyonis eggs (n = 3 per dose) or were fed B. procyonis-infected laboratory mice (n = 3 per dose; mice inoculated with 1000 or 250 eggs). Fecal samples were analysed via flotation and a commercial coproantigen ELISA designed for detection of Toxocara spp. Two of 12 dogs (both received low dose larvae) developed patent infections; all 12 raccoons became infected with 10 developing patent infections. Compared with dogs, prepatent periods were shorter in raccoons and maximum egg outputs were much greater. Baylisascaris procyonis coproantigens were detectable via ELISA in all raccoons and the patently infected dogs. Finally, dogs spontaneously lost infections while all patently infected raccoons shed eggs until conclusion of the study. Our results demonstrate that dogs are clearly suboptimal hosts showing limited parasite establishment and fecundity vs raccoons. Despite the low competence, patently infected dogs still pose a risk for human exposure, emphasizing the importance of control measures.

Perspective on control options forEchinococcus multiloculariswith particular reference to Japan

Parasitology ◽  
2003 ◽  
Vol 127 (S1) ◽  
pp. S159-S172 ◽  
Author(s):  
A. ITO ◽  
T. ROMIG ◽  
K. TAKAHASHI
Keyword(s):  
Close Contact ◽  
Integrated Control ◽  
Risk Behaviour ◽  
Control Measures ◽  
Domestic Dogs ◽  
Western China ◽  
Preventive Strategies ◽  
Preventive Chemotherapy ◽  
Information Campaigns ◽  
Control Options

Following a brief introduction of recent advances in molecular and immunological technology for detection of persons and animals infected withEchinococcus multilocularisand an overview of the current situation of alveolar echinococcosis (AE) in Japan, perspectives on control options are discussed with reference to different epidemiological situations. AE is considered the most serious parasitic zoonosis in temperate and arctic regions of the northern hemisphere. The number of human cases differs drastically among regions. While high numbers of patients are apparently associated with highE. multilocularisprevalence in domestic dogs, e.g. in parts of Alaska and western China, the number of cases is moderate or low in areas where the parasite is mainly transmitted by wild canid species (e.g. in central Europe or temperate North America). However, the severity of the disease, the absence of curative treatment for most cases, the high cost of long-term chemotherapy and the anxiety caused for the population in highly endemic areas call for the development of preventive strategies even in regions where human AE is rare. Furthermore, in view of (1) drastically increasing numbers and infection rates of foxes involved in transmission ofE. multilocularis, and (2) increasingly close contact between humans and foxes e.g. in Europe and Japan, there is considerable concern that AE incidences may in future increase in these regions. Control options depend on a variety of factors including the species of canid principally responsible for transmission and the socio-economic situation in the region. Where domestic dogs (stray or owned) are the principal hosts forE. multilocularis, control options can include those applicable toE. granulosus, i.e. reduction of the number of stray dogs, registration and regular preventive chemotherapy of owned dogs, and information campaigns for the population promoting low-risk behaviour for man and dogs. WhereE. multilocularisis mainly transmitted by wild canids, the situation is far more difficult with preventive strategies still being in trial stage. Integrated control measures could include prevention information campaigns, restricting access of pet animals (dogs and cats) to rodents, chemotherapy of foxes on local or regional scales, and strategies to minimize contacts between people and foxes.

scholarly journals Public farms: hygiene and zoonotic agents

2007 ◽  
Vol 135 (7) ◽  
pp. 1174-1183 ◽  
Author(s):  
A. E. HEUVELINK ◽  
S. M. VALKENBURGH ◽  
J. J. H. C. TILBURG ◽  
C. VAN HEERWAARDEN ◽  
J. T. M. ZWARTKRUIS-NAHUIS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Human Exposure ◽  
Public Awareness ◽  
Zoonotic Diseases ◽  
Control Measures ◽  
Public And Private ◽  
Faecal Material ◽  
Standard Questionnaire ◽  
Hygiene Measures

SUMMARYIn three successive years, we visited petting farms (n=132), care farms (n=91), and farmyard campsites (n=84), respectively, and completed a standard questionnaire with the objective of determining the hygienic status of these farms and describing hygiene measures implemented to reduce the risk of transmission of zoonotic agents from the animals to humans. For at least 85% of the farms, the overall impression of hygiene was recorded as good. However, more attention must be paid to: informing visitors on hygiene and handwashing, provision of handwashing facilities, and a footwear cleaning facility. Examination of samples of freshly voided faeces resulted in the detection of Shiga toxin-producingEscherichia coliO157 and/orSalmonellaspp. and/orCampylobacterspp. at almost two-thirds (64·9%) of the petting farms, and around half of the care farms (56·0%) and farmyard campsites (45·2%). These data reinforce the need for control measures for both public and private farms to reduce human exposure to livestock faeces and thus the risk of transmission of zoonotic diseases. Public awareness of the risk associated with handling animals or faecal material should be increased.

scholarly journals Serological detection of infection with canine distemper virus, canine parvovirus and canine adenovirus in communal dogs from Zimbabwe

2014 ◽  
Vol 85 (1) ◽  
Author(s):  
Anna McRee ◽  
Rebecca P. Wilkes ◽  
Jessica Dawson ◽  
Roger Parry ◽  
Chris Foggin ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Canine Distemper Virus ◽  
Wildlife Conservation ◽  
Canine Parvovirus ◽  
Control Measures ◽  
Domestic Dogs ◽  
Sub Saharan Africa ◽  
Enzyme Linked Immunosorbent Assay ◽  
Canine Distemper ◽  
The Impact

Domestic dogs are common amongst communities in sub-Saharan Africa and may serve as important reservoirs for infectious agents that may cause diseases in wildlife. Two agents of concern are canine parvovirus (CPV) and canine distemper virus (CDV), which may infect and cause disease in large carnivore species such as African wild dogs and African lions, respectively. The impact of domestic dogs and their diseases on wildlife conservation is increasing in Zimbabwe, necessitating thorough assessment and implementation of control measures. In this study, domestic dogs in north-western Zimbabwe were evaluated for antibodies to CDV, CPV, and canine adenovirus (CAV). These dogs were communal and had no vaccination history. Two hundred and twenty-five blood samples were collected and tested using a commercial enzyme-linked immunosorbent assay (ELISA) for antibodies to CPV, CDV, and CAV. Of these dogs, 75 (34%) had detectable antibodies to CDV, whilst 191 (84%) had antibodies to CPV. Antibodies to canine adenovirus were present in 28 (13%) dogs. Canine parvovirus had high prevalence in all six geographic areas tested. These results indicate that CPV is circulating widely amongst domestic dogs in the region. In addition, CDV is present at high levels. Both pathogens can infect wildlife species. Efforts for conservation of large carnivores in Zimbabwe must address the role of domestic dogs in disease transmission.

scholarly journals Efficacy of some insecticides and biopesticides for the management of white stem borer, Scirpophaga fusciflua Hampson in paddy

2018 ◽  
Author(s):  
Vikas Tandon ◽  
Ajai BSrivastava
Keyword(s):  
Field Experiment ◽  
Grain Yield ◽  
Untreated Control ◽  
Low Dose ◽  
Stem Borer ◽  
Control Measures ◽  
Effective Control ◽  
Viable Option ◽  
Efficacy Data

The field experiment was conducted on paddy at farmer’s field in the Kangra district, to find out the effectiveness and economically viable control measures for the management of white stem borer. Application of various insecticides viz. flubendiamide 48% SC @ 50 ml ha-1, rynaxypyr 20 SC @ 150 ml ha-1, dinotefuran 20 SG @ 200 g ha-1 , monocrotophos 36 SL @ 850 ml ha-1 and two biopesticides viz. melia 5% @ 2.5 L ha-1and eupatorium 5% @ 2.5 L ha-1, were tested along with untreated control. All the insecticidal treatments were found significantly superior to untreated control. Flubendiamide 48% SC @ 50 ml ha-1 and rynaxypyr 20 SC @ 150 ml ha-1 were found most promising with minimum dead heart and white ears. The data on dead heart, white ear incidence and grain yield showed that all the insecticides were found to have effective control against stem borer on paddy. Considering the efficacy data with very low dose of flubendiamide 48% SC proved to be better and economically viable option for management of stem borer.

scholarly journals Possible future waves of SARS-CoV-2 infection generated by variants of concern with a range of characteristics

2021 ◽  
Author(s):  
Louise Dyson ◽  
Edward M Hill ◽  
Sam Moore ◽  
Jacob Curran-Sebastian ◽  
Michael J Tildesley ◽  
...  
Keyword(s):  
Immune Escape ◽  
Deterministic Model ◽  
Control Measures ◽  
Transmission Model ◽  
Vaccination Rates ◽  
Infection Dynamics ◽  
Potential Impact ◽  
Age Structured ◽  
Ongoing Infection ◽  
Viral Reproduction

Ongoing infection with, and associated viral reproduction of, SARS-CoV-2 provides opportunities for the virus to acquire advantageous mutations, which may alter viral transmissibility and disease severity, and allow escape from natural or vaccine-derived immunity. The number of countries reporting Variants of Concern (VOCs) with such mutations continues to rise. Here, we investigate two scenarios for third waves of the COVID pandemic: one driven by increased transmissibility, and another driven by immune escape. We do this using three mathematical models: a parsimonious susceptible-latent-infectious-recovered (SEIR) deterministic model with homogeneous mixing, an age-structured SARS-CoV-2 transmission model and a stochastic importation model. We calibrated our models to the situation in England in May 2021, although the insights will generalise to other contexts. We therefore accurately captured infection dynamics and vaccination rates, and also used these to explore the potential impact of a putative new VOC-targeted vaccine. Epidemiological trajectories for putative VOCs are wide-ranging and heavily dependent on their transmissibility, immune escape capability, and the time at which a postulated VOC-targeted vaccine may be introduced. We demonstrate that a VOC with either a substantial transmission advantage over resident variants, or the ability to evade vaccine-derived and prior immunity, is expected to generate a wave of infections and hospitalisations comparable to those seen in the winter 2020-21 wave. Moreover, a variant that is less transmissible, but shows partial immune-escape could provoke a wave of infection that would not be revealed until control measures are further relaxed.

Generalised Model of the Effect of Different Control Measures in Reducing Health Risks from Waste Reuse†

1989 ◽  
Vol 21 (3) ◽  
pp. 235-235
Author(s):  
U. J. Blumenthal ◽  
M. Strauss ◽  
D. D. Mara ◽  
S. Cairncross
Keyword(s):  
Health Risks ◽  
Human Exposure ◽  
Waste Treatment ◽  
Health Protection ◽  
Control Measures ◽  
Local Context ◽  
Protection Measures ◽  
Waste Reuse ◽  
Treatment Processes ◽  
Definition Of

Health risks from wastewater and excreta reuse are assessed using an epidemiological definition of attributable risk instead of the presence of a microbiological hazard. Measures for health protection need not rely on total pathogen removal by waste treatment processes but may include ways to prevent direct human exposure to the wastes. The range of possible options for health protection includes: waste treatment, crop restriction, localised application methods, control of human exposure, and combinations of the different methods. A generalised model is used to show the effectiveness of each option in reducing health risks to agricultural workers and consumers of the crops grown. Three different regimes are available for rendering waste reuse ‘safe' to both workers and consumers, and several regimes are capable of reducing but not eliminating health risks. Case studies are given of the application of the model to wastewater and excreta reuse in agriculture and aquaculture in 6 different countries. The model can be used to aid decisions by planners and engineers to ensure that health protection measures are targetted towards specific exposed groups in the population, within their local context. † The full version of this article will appear in Water Science and Technology, 2l(6/7), 567-577 (1989).

Coronavirus: the science behind infection control and human exposure

2021 ◽  
Vol 26 (1) ◽  
pp. 14-17
Author(s):  
Alison Phillis
Keyword(s):  
Infection Control ◽  
Human Exposure ◽  
Control Measures ◽  
Infection Control Measures ◽  
Factors Influencing ◽  
Viral Particles ◽  
Therapeutic Development ◽  
Environmental Decontamination ◽  
The Individual ◽  
New Reservoir

Coronavirus SARS-2 (SARS-CoV-2) is the virus responsible for the disease known as COVID-19. The global community is struggling with the health and economic repercussions of this novel disease, and this article is part of a series that seeks to explore and explain the science behind the foci of infection control measures being considered at both the individual and population health levels. Understanding the factors influencing the ability of this virus to select an appropriate host, breach initial defences and successfully assume a new reservoir from which to disseminate and disperse infective viral particles is considered here. Brief reference is made to infection control measures such as effective hand hygiene, glove usage, environmental decontamination and social distancing guidance against the context of the specific evidence around COVID-19 transmission. Predictors of poorer outcome are introduced in the light of these being target themes for therapeutic development.

Generalised Model of the Effect of Different Control Measures in Reducing Health Risks from Waste Reuse

1989 ◽  
Vol 21 (6-7) ◽  
pp. 567-577 ◽  
Author(s):  
U. J. Blumenthal ◽  
M. Strauss ◽  
D. D. Mara ◽  
S. Cairncross
Keyword(s):  
Health Risks ◽  
Human Exposure ◽  
Waste Treatment ◽  
Health Protection ◽  
Control Measures ◽  
Local Context ◽  
Protection Measures ◽  
Waste Reuse ◽  
Treatment Processes ◽  
Definition Of

Health risks from wastewater and excreta reuse are assessed using an epidemiological definition of attributable risk instead of the presence of a microbiological hazard. Measures for health protection need not rely on total pathogen removal by waste treatment processes but may include ways to prevent direct human exposure to the wastes. The range of possible options for health protection includes: waste treatment, crop restriction, localised application methods, control of human exposure, and combinations of the different methods. A generalised model is used to show the effectiveness of each option in reducing health risks to agricultural workers and consumers of the crops grown. Three different regimes are available for rendering waste reuse ‘safe' to both workers and consumers, and several regimes are capable of reducing but not eliminating health risks. Case studies are given of the application of the model to wastewater and excreta reuse in agriculture and aquaculture in 6 different countries. The model can be used to aid decisions by planners and engineers to ensure that health protection measures are targetted towards specific exposed groups in the population, within their local context.

Light microscopical structure and ultrastructure of aBesnoitiasp. in the naturally infected lizardAmeiva ameiva(Teiidae) from north Brazil, and in experimentally infected mice

Parasitology ◽  
2001 ◽  
Vol 123 (3) ◽  
pp. 247-255 ◽  
Author(s):  
I. PAPERNA ◽  
R. LAINSON
Keyword(s):  
Endoplasmic Reticulum ◽  
Definitive Host ◽  
Domestic Cat ◽  
Laboratory Mice ◽  
Boa Constrictor ◽  
North Brazil ◽  
In Captivity ◽  
Juvenile Specimen ◽  
Structure And Ultrastructure ◽  
Intraperitoneal Inoculation

ABesnoitiaspecies of the teiid lizardAmeiva ameiva(L.), from north Brazil was established in laboratory mice and hamster by the intraperitoneal inoculation of bradyzoites in the tissue cysts. In the lizards all the cyst wall layers were closely apposed. In the mice the layers of the wall were distinguishable, and ultrastructurally the inner cytoplasmic layer contained either a tight network of endoplasmic reticulum or packed mitochondria or both. These components were less frequent or sparse in the inner cytoplasmic layer of cysts in the lizard. The only animals available for experiments in attempts to indicate the definitive host of the parasite were 3 kittens of the domestic cat and a juvenile specimen of the snakeBoa constrictorraised in captivity. No evidence of infection could be detected in these animals after feeding them with the tissues of mice harbouring cysts with very large number of bradyzoites.

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