Animal models of intestinal nematode infections of humans

Parasitology ◽  
2000 ◽  
Vol 121 (S1) ◽  
pp. S97-S111 ◽  
Author(s):  
J. BOES ◽  
A.B. HELWIGH

In this paper we discuss several established and potential animal models for human parasitic infection, with a focus on rodent, pig and primate models and the nematodes Ascaris, Trichuris and Toxocara spp. Firstly, we discuss the relevance of choosing a suitable animal host to fit the particular study hypothesis, and the interaction between mathematical modelling and animal models. Secondly, we review the use of animal models for the study of nutrition-parasite interaction, evaluation of treatment and control strategies, and bacteria-parasite interactions. We show that rodent, pig and primate models are all very useful in parasitological research, and that each model has its limitations. However, based on recent experience with the pig-Ascaris and pig-Trichuris models, a more extensive use of the pig-parasite model is advocated, especially for the study of the interaction between human malnutrition and helminth infection, and congenital helminth infection.

2018 ◽  
Vol 10 (7) ◽  
pp. 1
Author(s):  
Mavianis Pinilla ◽  
Julio C. Giraldo ◽  
Lucy M. Villafañe ◽  
Jaime Lorduy ◽  
Sandy Rocha ◽  
...  

Cysticercosis is a parasitic infection caused by the larvae of the pork tapeworm, Taenia solium. It is acquired through fecal-oral contamination, and it can affect humans and pigs. In Colombia, this is an endemic infection especially in locations where breeding and commercialization of pigs are performed under poorly hygienic conditions, such as in Maria La Baja, Department of Bolívar. However, seroprevalence of anti-cysticercus antibodies in pigs or pig breeders at these locations has not been determined. Thus, using indirect immunoassays we quantified anti-cysticercus antibodies in serum samples of pigs (n=254) and pig breeders (n=121) in Maria La Baja. Furthermore, a questionnaire was applied in order to determine environmental, cultural, and socioeconomic variables. Anti-cysticercus antibodies were detected in 36.6% (93/254) of pigs and 44.6% (54/121) of pig breeders. A significant causal association was identified for daily cleaning of pigsties and having anti-cysticercus antibodies with an aOR = 15.16 (CI 95%: 2.13 - 107.86; p = 0.0002). No significant associations were identified between the evaluated variables and seroprevalence of anti-cysticercus antibodies in pigs. Our study indicates that there is a high seroprevalence of anti-cysticercus antibodies in humans and pigs in locations where handling of pigs is performed under poor hygienic conditions. Our results suggest that there is a need to design and implement prevention and control strategies in Maria La Baja in order to reduce transmission of this disease.      


2021 ◽  
Vol 15 (5) ◽  
pp. e0009449
Author(s):  
Maylis Layan ◽  
Simon Dellicour ◽  
Guy Baele ◽  
Simon Cauchemez ◽  
Hervé Bourhy

Background Rabies is a fatal yet vaccine-preventable disease. In the last two decades, domestic dog populations have been shown to constitute the predominant reservoir of rabies in developing countries, causing 99% of human rabies cases. Despite substantial control efforts, dog rabies is still widely endemic and is spreading across previously rabies-free areas. Developing a detailed understanding of dog rabies dynamics and the impact of vaccination is essential to optimize existing control strategies and developing new ones. In this scoping review, we aimed at disentangling the respective contributions of mathematical models and phylodynamic approaches to advancing the understanding of rabies dynamics and control in domestic dog populations. We also addressed the methodological limitations of both approaches and the remaining issues related to studying rabies spread and how this could be applied to rabies control. Methodology/principal findings We reviewed how mathematical modelling of disease dynamics and phylodynamics have been developed and used to characterize dog rabies dynamics and control. Through a detailed search of the PubMed, Web of Science, and Scopus databases, we identified a total of n = 59 relevant studies using mathematical models (n = 30), phylodynamic inference (n = 22) and interdisciplinary approaches (n = 7). We found that despite often relying on scarce rabies epidemiological data, mathematical models investigated multiple aspects of rabies dynamics and control. These models confirmed the overwhelming efficacy of massive dog vaccination campaigns in all settings and unraveled the role of dog population structure and frequent introductions in dog rabies maintenance. Phylodynamic approaches successfully disentangled the evolutionary and environmental determinants of rabies dispersal and consistently reported support for the role of reintroduction events and human-mediated transportation over long distances in the maintenance of rabies in endemic areas. Potential biases in data collection still need to be properly accounted for in most of these analyses. Finally, interdisciplinary studies were determined to provide the most comprehensive assessments through hypothesis generation and testing. They also represent new avenues, especially concerning the reconstruction of local transmission chains or clusters through data integration. Conclusions/significance Despite advances in rabies knowledge, substantial uncertainty remains regarding the mechanisms of local spread, the role of wildlife in dog rabies maintenance, and the impact of community behavior on the efficacy of control strategies including vaccination of dogs. Future integrative approaches that use phylodynamic analyses and mechanistic models within a single framework could take full advantage of not only viral sequences but also additional epidemiological information as well as dog ecology data to refine our understanding of rabies spread and control. This would represent a significant improvement on past studies and a promising opportunity for canine rabies research in the frame of the One Health concept that aims to achieve better public health outcomes through cross-sector collaboration.


Author(s):  
Getachew Belay ◽  
Pawlos Reji ◽  
Berhanu Erko ◽  
Mengistu Legesse ◽  
Mulugeta Belay

Background: A survey of intestinal parasitic infections and malnutrition in different regions or localities is a very important step in developing appropriate prevention and control strategies.Objectives: The objective of this study was to investigate the magnitude of intestinal parasitic infections and malnutrition amongst first-cycle primary schoolchildren in Adama town,Ethiopia.Method: A total of 358 children from four primary schools in Adama town were included for stool examination, weight for age, height for age, weight for height and socio-economic status of the family.Results: The result of stool examinations showed that 127 (35.5%) of the study subjects were infected by one or more parasite. The most frequent parasites were Entamoeba histolytica/dispar (12.6%) and Hymenolopis nana (8.9%). The rate of intestinal parasitic infection was not significantly associated with sex, age or socio-economic factors and nutrition (P > 0.05). The overall prevalence of malnutrition was 21.2%. Those children whose families had a monthly income of less than 200 ETB (Ethiopian birr) were highly affected by malnutrition (P < 0.05),but family education was not identified as a factor for malnutrition amongst schoolchildren.Conclusion: The prevalence of E. histolytica/dispar and H. nana could be of public health importance and calls for appropriate control strategies, and the high prevalence of malnutrition amongst children from poor families requires intervention.


2019 ◽  
Vol 51 (6) ◽  
pp. 817-826 ◽  
Author(s):  
Tadesse Menjetta ◽  
Serkadis Debalke ◽  
Daniel Dana

AbstractSchistosomiasis is a neglected tropical parasitic disease caused by different species of genus Schistosoma. Schistosoma mansoni causes a severe intestinal parasitic infection of high public and medical importance in Ethiopia. This study aimed to determine the prevalence of, and risk factors for, S. mansoni infection among the fishermen of Lake Hawassa, southern Ethiopia, using a cross-sectional study design. A total of 243 fishermen were selected from the Hawassa Town Fishermen Association’s list in 2013. Data on socio-demographic characteristics and risk factors were collected from the fishermen using semi-structured questionnaires. Stool samples were collected and processed using the Kato–Katz thick smear technique. The overall prevalence of S. mansoni among the fishermen was 29.21% and the mean intensity of infection was 158.88 eggs per gram (EPG). The overall prevalence of intestinal helminths, including S. mansoni, was 69.54%. Similar prevalences of S. mansoni were recorded in age groups 15–19, 20–24 and 25–29 years: 31.82%, 31.75% and 31.94%, respectively. Fishermen who swam a minimum of once a week in Lake Hawassa were 2.92 times (95% CI: 1.554, 5.502) more likely to have acquired S. mansoni infection than those who swam in the lake less than once a week. The results indicate moderate endemicity of S. mansoni infection among the fishermen of Lake Hawassa. These fishermen could be a potentially high-risk group for S. mansoni infection and might be responsible for the transmission of infection to other segments of the community visiting the lake for recreation. Moreover, a high prevalence of soil-transmitted helminths (STHs) was recorded among the fishermen. Integrated prevention and control strategies for schistosomiasis and STHs by different sectors are needed to tackle this problem.


2020 ◽  
Author(s):  
Daniel Poremski ◽  
Sandra Henrietta Subner ◽  
Grace Lam Fong Kin ◽  
Raveen Dev Ram Dev ◽  
Mok Yee Ming ◽  
...  

The Institute of Mental Health in Singapore continues to attempt to prevent the introduction of COVID-19, despite community transmission. Essential services are maintained and quarantine measures are currently unnecessary. To help similar organizations, strategies are listed along three themes: sustaining essential services, preventing infection, and managing human and consumable resources.


1989 ◽  
Vol 24 (3) ◽  
pp. 463-477
Author(s):  
Stephen G. Nutt

Abstract Based on discussions in workshop sessions, several recurring themes became evident with respect to the optimization and control of petroleum refinery wastewater treatment systems to achieve effective removal of toxic contaminants. It was apparent that statistical process control (SPC) techniques are finding more widespread use and have been found to be effective. However, the implementation of real-time process control strategies in petroleum refinery wastewater treatment systems is in its infancy. Considerable effort will need to be expended to demonstrate the practicality of on-line sensors, and the utility of automated process control in petroleum refinery wastewater treatment systems. This paper provides a summary of the discussions held at the workshop.


Author(s):  
Ivan Herreros

This chapter discusses basic concepts from control theory and machine learning to facilitate a formal understanding of animal learning and motor control. It first distinguishes between feedback and feed-forward control strategies, and later introduces the classification of machine learning applications into supervised, unsupervised, and reinforcement learning problems. Next, it links these concepts with their counterparts in the domain of the psychology of animal learning, highlighting the analogies between supervised learning and classical conditioning, reinforcement learning and operant conditioning, and between unsupervised and perceptual learning. Additionally, it interprets innate and acquired actions from the standpoint of feedback vs anticipatory and adaptive control. Finally, it argues how this framework of translating knowledge between formal and biological disciplines can serve us to not only structure and advance our understanding of brain function but also enrich engineering solutions at the level of robot learning and control with insights coming from biology.


Sign in / Sign up

Export Citation Format

Share Document